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Sample records for severe slipped capital

  1. Slipped capital femoral epiphysis: A modern treatment protocol

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    Slavković Nemanja

    2009-01-01

    Full Text Available The treatment of a patient with slipped capital femoral epiphysis begins with an early diagnosis and accurate classification. On the basis of symptom duration, clinical findings and radiographs, slipped capital femoral epiphysis is classified as pre-slip, acute, acute-on-chronic and chronic. The long-term outcome of slipped capital femoral epiphysis is directly related to severity and the presence or absence of avascular necrosis and/or chondrolysis. Therefore, the first priority in the treatment of slipped capital femoral epiphysis is to avoid complications while securing the epiphysis from further slippage. Medical treatment of patients with acute and acute-on-chronic slipped capital femoral epiphysis, as well as those presented in pre-slip stage, is the safest, although time-consuming. Manipulations, especially forced and repeated, are not recommended due to higher avascular necrosis risk. The use of intraoperative fluoroscopy to assist in the placement of internal fixation devices has markedly increased the success of surgical treatment. Controversy remains as to whether the proximal femoral epiphysis in severe, chronic slipped capital femoral epiphysis should be realigned by extracapsular osteotomies or just fixed in situ. The management protocol for slipped capital femoral epiphysis depends on the experience of the surgeon, motivation of the patient and technical facilities.

  2. The role of capital realignment versus in situ stabilization for the treatment of slipped capital femoral epiphysis.

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    Souder, Christopher D; Bomar, James D; Wenger, Dennis R

    2014-12-01

    Slipped capital femoral epiphysis (SCFE) can be treated by a variety of methods with the traditional method of in situ pin fixation being most commonly used. More recently, the Modified Dunn (Mod. Dunn) procedure consisting of capital realignment has been popularized as a treatment method for SCFE, particularly for more severe cases. Over the last 5 years, our institution has selectively used this method for more complex cases. The purpose of this article is to evaluate the differences between these 2 treatment methods in terms of avascular necrosis (AVN) rate, reoperation rate, and complication rate. Eighty-eight hips that were surgically treated for SCFE between July 2004 and June 2012 met our inclusion criteria. The in situ fixation group included 71 hips, whereas 17 hips were anatomically reduced with the Mod. Dunn procedure. Loder classification, severity, acuity, complication rate, and reoperation rate were determined for the 2 cohorts. The χ analysis was performed to evaluate the relationship between the treatment method and outcome. As expected, stable slips did well with in situ pinning with no cases of AVN, even in more severe slips. Ten stable slips were treated with the Mod. Dunn approach and 2 (20%) developed AVN. Unstable slips were more difficult to treat with 3 of the 7 hips stabilized in situ developing AVN (43%). Two of the 7 unstable slips treated by the Mod. Dunn procedure developed AVN (29%). The other outcomes studied (reoperation rate and complication rate) were not significantly related to the surgical treatment method (P = 0.732 and 0.261, respectively). In situ pinning remains a safe and predictable method for treatment of stable SCFE with no AVN noted, even in severe slips. Attempts to anatomically reduce stable slips led to severe AVN in 20% of cases, thus this treatment approach should be considered with caution. Treatment of unstable slips remains problematic with high AVN rates noted whether treated by in situ fixation or capital

  3. Outcome of pinning in patients with slipped capital femoral epiphysis: risk factors associated with avascular necrosis, chondrolysis, and femoral impingement.

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    Ulici, Alexandru; Carp, Madalina; Tevanov, Iulia; Nahoi, Catalin Alexandru; Sterian, Alin Gabriel; Cosma, Dan

    2018-06-01

    Objective This study aimed to assess the principal risk factors that could lead to the most common long-term complications of slipped capital femoral epiphysis, such as avascular necrosis, chondrolysis, and hip impingement. Methods We conducted a single-centre, retrospective study and evaluated patients (70 patients, 81 hips) who were treated for slipped capital femoral epiphysis from 2010 to 2015 and who underwent pinning. We measured the severity of displacement radiologically using the Southwick angle. Postoperative radiographs were evaluated for the most frequent long-term complications of avascular necrosis (AVN), chondrolysis, and femoral acetabular impingement (FAI). Results We found seven cases of AVN, 14 cases of chondrolysis, and 31 hips had an α angle of 60°. Sex, ambulation, and symptoms did not affect development of these complications. Patients with a normal weight were almost two times more likely to develop FAI. Patients with moderate and severe slips had a similar percentage of AVN. In severe slips, 85.7% of patients had an α angle higher than 60°. Conclusions This study shows that severe slips have a higher risk of developing AVN and hip impingement. Every patient who suffers from SCFE (even the mildest forms) should be regularly checked for FAI.

  4. Case of slipped capital femoral epiphysis following radiation

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    Terada, Hiroshi; Usui, Hiroshi; Nakamura, Yutaka; Chiba, Masahiro; Yamaji, Shushin; Oba, Yoshihiro

    1987-06-01

    A 12-year-old boy presented with pain of the right hip joint and claudication. At the age of 7 months, the patient had received prophylactic irradiation of 30 Gy to the pelvic area including lumbar vertebrae and bilateral hip joints following extirpation of the right undescended testicle for embryonal carcinoma. Roentgenograph showed slipped capial femoral epiphysis. A review of the literature suggests that bone growth and hormonal changes in the early stage of puberty are involved, in addition to radiation damaged epiphyseal cartilage, in the pathophysiologic mechanisms of radiation induced slipped capital femoral epiphysis. (Namekawa, K.).

  5. Multiplanar CT assessment of femoral head displacement in slipped capital femoral epiphysis

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    Monazzam, Shafagh [Rady Children' s Hospital and Health Center, Department of Orthopedics, San Diego, CA (United States); Dwek, Jerry R. [Rady Children' s Hospital and Health Center, Department of Radiology, San Diego, CA (United States); Hosalkar, Harish S. [Center for Hip Preservation, Department of Orthopedic Surgery, TriCity Medical Center, Oceanside, CA (United States)

    2013-12-15

    With recent changing approaches to the management of slipped capital femoral epiphysis (SCFE), the accurate radiographic assessment of maximum extent of displacement is crucial for planning surgical treatment. To determine what plane best represents the maximum SCFE displacement as quantified by the head-neck angle difference (HNAD), whether HNAD can quantitatively differentiate the SCFE cohort from the normal cohort, based on CT, and how Southwick slip angle (SSA) compares to HNAD. We reviewed 19 children with SCFE (23 affected hips) with preoperative CT scans and 27 age- and sex-matched children undergoing abdominal CT for non-orthopedic problems. Head-neck angle (HNA), the angle between the femoral epiphysis and the neck axis, was measured in three planes on each hip and the HNAD (affected - unaffected hip) was determined. SSA was measured on radiographs. The coronal HNAD (mean 8.7 ) was less than both the axial-oblique (mean 30.7 ) and sagittal (mean 37.4 ) HNADs, which were also greater than the HNADs of the normal cohort. Grouping HNAD measurements by SSA severity classification did not consistently distinguish between SCFE severity levels. Axial-oblique and sagittal planes best represent the maximum SCFE displacement while biplanar radiograph may underestimate the extent of the displacement, thereby potentially altering the management between in situ pinning and capital realignment. (orig.)

  6. Progressive slip after removal of screw fixation in slipped capital femoral epiphysis: two case reports

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    Engelsma, Y.; Morgenstern, P.; van der Sluijs, J.A.; Witbreuk, M.M.

    2012-01-01

    Introduction. In slipped capital femoral epiphysis the femoral neck displaces relative to the head due to weakening of the epiphysis. Early recognition and adequate surgical fixation is essential for a good functional outcome. The fixation should be secured until the closure of the epiphysis to

  7. Surgical hip dislocation in treatment of slipped capital femoral epiphysis

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    Elmarghany Mohammed

    2017-01-01

    Full Text Available Background: Most surgeons advocate in situ fixation of the slipped epiphysis with acceptance of any persistent deformity in the proximal femur [Aronsson DD, Loder RT, Breur GJ, Weinstein SL (2006 Slipped capital femoral epiphysis: current concepts. J Am Acad Orthop Surg 14, 666–679]. This residual deformity can lead to osteoarthritis due to femoroacetabular cam impingement (FAI [Leunig M, Slongo T, Ganz R (2008 Subcapital realignment in slipped capital femoral epiphysis: surgical hip dislocation and trimming of the stable trochanter to protect the perfusion of the epiphysis. Instr Course Lect 57, 499–507]. Objective: The primary aim of our study was to report the results of the technique of capital realignment with Ganz surgical hip dislocation and its reproducibility to restore hip anatomy and function. Patients and methods: This prospective case series study included 30 patients (32 hips, 13 left (Lt hips, 19 right (Rt hips with stable chronic slipped capital femoral epiphysis (SCFE after surgical correction with a modified Dunn procedure. This study included 22 males and eight females. The mean age of our patients was 14 years (10–18 years. The mean follow-up period was 14.5 months (6–36 months. Results: Thirty hips had excellent and good clinical and radiographic outcomes with respect to hip function and radiographic parameters. Two patients had fair to poor clinical outcome including three patients who developed Avascular Necrosis (AVN. The difference between those who developed AVN and those who did not develop AVN was statistically significant in postoperative clinical scores (p = 0.0000. The mean slip angle of the femoral head was 52.5° ± 14.6 preoperatively and was corrected to a mean value of 5.6° ± 8.2° with mean correction of 46.85° ± 14.9° (p = 0.0000. The mean postoperative alpha angle was 51.15° ± 4.2° with mean correction of 46.70 ± 14.20 (p = 0.0000. In our series, the mean postoperative

  8. Slip of the capital femoral epiphysis: Revival of a method of assessment

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    Billing, L.; Ekloef, O.

    1984-01-01

    A simple and exact method for evaluation of suspected or overt slip of the femoral capital epiphysis is revived. This procedure gives an estimate of all degrees of abnormality from the early stages to those with gross deformity. In our experience slip of the femoral capital epiphysis is always posterior and in approximately 80% of cases bilateral. Therefore, bot hips should be examined whenever this condition is suspected. The method provides for examination of each hip separately. Strict adherence to the procedure also provides a precise way of assessing the femoral anteversion angle, significant in many orthopedic disorders. For the latter purpose access to a particular nomogram is mandatory. (orig.)

  9. Slipped upper femoral epiphysis: Outcome after in situ fixation and capital realignment technique

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    Sanjay Arora

    2013-01-01

    Results: Clinical outcome as assessed by Merle d′ Aubigne score was excellent in 6, good in 10, fair in 6 and poor in 1. Half of the in situ fixation patients underwent osteoplasty procedure for femoroacetabular impingement and 5 more were symptomatic. The head neck offset and α angle after in situ pinning were -1.12 ± 3 mm and 66.05 ± 9.7°, respectively and this improved to 8.7 mm and 49°, respectively, after osteoplasty. One child in the pinning group had chondrolysis. Eight patients with severe slip underwent capital realignment. Mean followup was 20.15 months. The anterior head neck offset and α angle were corrected to 6.8 ± 1.72 mm and 44.6 ± 7.0° mm, respectively. Two children with unstable slip in the capital realignment group had avascular necrosis which was diagnosed at presentation by bone scan. Conclusion: High BMI, vitamin D deficiency and endocrine disorders are associated with SUFE in India and should be evaluated as some of these are amenable to prevention and treatment. Most patients treated with in situ pinning developed femoroacetabular impingement. The early results after capital realignment procedure are encouraging and help to avoid a second procedure which is needed in a majority of patients who underwent in situ pinning.

  10. Magnetic resonance imaging at primary diagnosis cannot predict subsequent contralateral slip in slipped capital femoral epiphysis

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    Wensaas, Anders [Akershus University Hospital, Department of Orthopaedic Surgery, Loerenskog (Norway); Wiig, Ola; Terjesen, Terje [Oslo University Hospital, Department of Orthopaedic Surgery, Rikshospitalet (Norway); Castberg Hellund, Johan; Khoshnewiszadeh, Behzad [Oslo University Hospital, Department of Radiology and Nuclear Medicine, Ullevaal (Norway)

    2017-12-15

    Prophylactic fixation of the contralateral hip in slipped capital femoral epiphysis (SCFE) is controversial, and no reliable method has been established to predict subsequent contralateral slip. The main purpose of this study was to evaluate if magnetic resonance imaging (MRI) performed at primary diagnosis could predict future contralateral slip. Twenty-two patients with unilateral SCFE were included, all had MRI of both hips taken before operative fixation. Six different parameters were measured on the MRI: the MRI slip angle, the greatest focal widening of the physis, the global widening of the physis measured at three locations (the midpoint of the physis and 1 cm lateral and medial to the midpoint), periphyseal (epiphyseal and metaphyseal) bone marrow edema, the presence of pathological joint effusion, and the amount of joint effusion measured from the lateral edge of the greater trochanter. Mean follow-up was 33 months (range, 16-63 months). Six patients were treated for contralateral slip during the follow-up time and a comparison of the MRI parameters of the contralateral hip in these six patients and in the 16 patients that remained unilateral was done to see if subsequent contralateral slip was possible to predict at primary diagnosis. All MRI parameters were significantly altered in hips with established SCFE compared with the contralateral hips. However, none of the MRI parameters showed any significant difference between patients who had a subsequent contralateral slip and those that remained unilateral. MRI taken at primary diagnosis could not predict future contralateral slip. (orig.)

  11. Valgus Slipped Capital Femoral Epiphysis in Patient with Hypopituitarism

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    Yoshihiro Kotoura

    2017-01-01

    Full Text Available Slipped capital femoral epiphysis (SCFE is a common disease of adolescent and the epiphysis is positioned more posteromedially in relation to the femoral neck shaft with varus SCFE; however, posterolateral displacement of the capital epiphysis, valgus SCFE, occurs less frequently. We report a case of valgus SCFE in a 17-year-old boy with hypopituitarism. After falling down, he experienced difficulty in walking. The radiographs were inconclusive; however three-dimensional computed tomography images showed lateral displacement of the epiphysis on the right femoral head. Valgus SCFE was diagnosed. The patient underwent in situ pinning of both sides. In situ pinning on the left side was performed as a prophylactic pinning because of endocrine abnormalities. At the 1-year follow-up, he could walk without any difficulty and there were no signs of pain. The epiphysis is commonly positioned more posteromedially in relation to the femoral neck shaft with most SCFE, but, in this case, the epiphysis slipped laterally. Differential diagnosis included femoral neck fracture (Delbet-Colonna type 1; however, this was less likely due to the absence of other clinical signs. Therefore, we diagnosed the patient as SCFE. When children complain of leg pain and limp, valgus SCFE that may not be visualized on anteroposterior radiographs needs to be considered.

  12. Analysis of slipped capital femoral epiphysis

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    Magid, D.; Fishman, E.K.; Sponseller, P.D.; Griffin, P.P.

    1988-01-01

    CT with multiplanar reconstruction (CT/MPR) was used to assess 25 adolescents with known or suspected slipped capital femoral epiphysis (SCFE). CT/MPR localizes the epiphysis in three planes, establishing its relationship to the acetabulum and the metaphyseal neck. MPR facilitates measurements of head-neck angles, residusal head-neck contact, and relative retrovision. CT/MPR may establish the true age of the epiphyseal failure and can reveal subtle SCFE in the face of normal plain films. Patients often present with confusing histories; clues to the true age of failure include subtle signs of healing, remodeling, or new bone buttressing. Characterization of acute versus chronic conditions influences preoperative planning. Postoperatively, CT/MPR confirms early results and follows epiphyseal fusion and remodelling. It also detects complications, such as pin or graft migration avascular necrosis (AVN), or chondrolysis

  13. Bilateral slipped capital femoral epiphysis occuring in an adult with acromegalic gigantism.

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    Feydy, A; Carlier, R Y; Mompoint, D; Rougereau, G; Patel, A; Vallée, C

    1997-03-01

    The etiology of slipped capital femoral epiphysis is still unknown. Traumatic, endocrine, toxic, and mechanical causes have all been hypothesized. It is well documented that the highest incidence occurs during the adolescent growth spurt, suggesting the role of an endocrine abnormality. We report a case that supports this hypothesis.

  14. Fluid Pressures at the Shoe-Floor-Contaminant Interface During Slips: Effects of Tread & Implications on Slip Severity

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    Beschorner, Kurt E.; Albert, Devon L.; Chambers, April J.; Redfern, Mark S.

    2018-01-01

    Previous research on slip and fall accidents has suggested that pressurized fluid between the shoe and floor is responsible for initiating slips yet this effect has not been verified experimentally. This study aimed to 1) measure hydrodynamic pressures during slipping for treaded and untreaded conditions; 2) determine the effects of fluid pressure on slip severity; and 3) quantify how fluid pressures vary with instantaneous resultant slipping speed, position on the shoe surface, and throughout the progression of the slip. Eighteen subjects walked on known dry and unexpected slippery floors, while wearing treaded and untreaded shoes. Fluid pressure sensors, embedded in the floor, recorded hydrodynamic pressures during slipping. The maximum fluid pressures (mean+/−standard deviation) were significantly higher for the untreaded conditions (124 +/−75 kPa) than the treaded conditions (1.1 +/−0.29 kPa). Maximum fluid pressures were positively correlated with peak slipping speed (r = 0.87), suggesting that higher fluid pressures, which are associated with untreaded conditions, resulted in more severe slips. Instantaneous resultant slipping speed and position of sensor relative to the shoe sole and walking direction explained 41% of the fluid pressure variability. Fluid pressures were primarily observed for untreaded conditions. This study confirms that fluid pressures are relevant to slipping events, consistent with fluid dynamics theory (i.e. the Reynolds equation), and can be modified with shoe tread design. The results suggest that the occurrence and severity of unexpected slips can be reduced by designing shoes/floors that reduce underfoot fluid pressures. PMID:24267270

  15. Long-term evolution of slipped capital femoral epiphysis treated by in situ fixation: a 26 years follow-up of 11 hips

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    Jérôme Murgier

    2014-06-01

    Full Text Available Slipped capital femoral epiphysis (SFCE may lead to femoro acetabular impingement and long-term function impairment, depending on initial displacement and treatment. There are several therapeutic options which include in situ fixation (ISF. The objective of this study was to evaluate long-term functional and radiographic outcomes of patients with SFCE treated with ISF. We conducted a single-center, retrospective study evaluating the clinical and radiographic outcomes of SCFE in situ fixation with a mean follow-up of 26 years (10- 47. Analysis of preoperative and last follow up radiographs was performed. The functional status of the hip was evaluated according to the Oxford hip score-12 and the radiographic osteoarthritis stage was rated according to Tönnis classification. Signs of femoro acetabular impingement were sought. Ten patients (11 hips were included. The average initial slip was 33.5° (10-62. At final follow up, the average Oxford hip score was 19.3 (12-37, it was good for groups who had a small initial slip (16.7 or moderate (17 and fair for the severe group (27. Average Tönnis grade was 1.3 (0- 3. The average alpha angle was 65.3° (50- 80°. Femoro acetabular impingement was likely in 100% of patients with severe slip, in 50% of patients with moderate slip and in 33% of patients with a slight slip. In situ fixation generated poor functional results, substantial hip osteoarthritis and potential femoro acetabular impingement in moderate to severe SCFE’s. However, in cases with minor displacement, functional and radiographic results are satisfactory. The cut off seems to be around 30° slip angle, above which other treatment options should be considered.

  16. Asynchronous slipped capital femoral epiphysis in a patient with a seizure disorder: case report and review of the literature.

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    Patterson, Diana C; Price, Andrew E

    2018-05-01

    Debate remains about the appropriate treatment of the asymptomatic side following treatment of a unilateral slipped capital femoral epiphysis (SCFE). A 12-year-old boy with a seizure disorder presented with an unstable SCFE on the left hip following a seizure. He underwent percutaneous pinning of the left only. At 8 months postoperatively, he returned with an unstable slip of the right hip, again following a seizure. No literature discussing the treatment of patients with risk of SCFE and seizure disorders was identified. Further study may identify an increased incidence of contralateral slip following an initial slip in this population. If a greater risk exists, contralateral prophylactic fixation at time of index surgery may be indicated.

  17. Chronic Bilateral Slipped Capital Femoral Epiphysis as an Unusual Presentation of Congenital Panhypopituitarism due to Pituitary Hypoplasia in a 17-Year-Old Female

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    Sasigarn A. Bowden

    2009-01-01

    Full Text Available We report an interesting case of a 17-year-old normal-statured female who was diagnosed with congenital panhypopituitarism due to pituitary hypoplasia at the presentation of bilateral slipped capital femoral epiphysis. We emphasized the importance of endocrinologic evaluation in patients with atypical slipped capital femoral epiphysis to prevent potential complication of adrenal crisis during surgery. This case also demonstrates growth without growth hormone which resulted in a delay in diagnosis of congenital hypopituitarism in this patient.

  18. Chronic Bilateral Slipped Capital Femoral Epiphysis as an Unusual Presentation of Congenital Panhypopituitarism due to Pituitary Hypoplasia in a 17-Year-Old Female

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    Klingele KevinE

    2009-11-01

    Full Text Available We report an interesting case of a 17-year-old normal-statured female who was diagnosed with congenital panhypopituitarism due to pituitary hypoplasia at the presentation of bilateral slipped capital femoral epiphysis. We emphasized the importance of endocrinologic evaluation in patients with atypical slipped capital femoral epiphysis to prevent potential complication of adrenal crisis during surgery. This case also demonstrates growth without growth hormone which resulted in a delay in diagnosis of congenital hypopituitarism in this patient.

  19. [Growth and deformity after in situ fixation of slipped capital femoral epiphysis].

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    Druschel, C; Placzek, R; Funk, J F

    2013-08-01

    For mild to moderate slipped capital femoral epiphysis (SCFE) in situ fixation is the current treatment standard. However, concerning the implant selection (screw versus k-wires) as well as the prophylactic stabilisation of the non-affected hip, controversies still exist. The aim of this study was to analyse femoral residual growth and femoral deformities after in situ fixation of SCFE either with k-wires or screws. We conducted a retrospective analysis of the radiographs of adolescents treated for SCFE in our department between 01/2003 and 02/2011. To evaluate femoral growth the articulo-trochanteric distance, centro-trochanteric distance, caput-collum-diaphyseal angle, pin-joint ratio and pin-physis ratio were determined. The femoral deformity was assessed by measuring the sphericity of the femoral head. Degenerative changes were evaluated in the final radiographs. Statistical analysis was performed concerning differences between therapeutically and prophylactically treated hips as well as stabilisations with k-wires and screws. A total of 22 patients (female : male = 14 : 8, mean age girls: 11 ± 1 years, boys: 13 ± 2 years) with 26 slipped capital femoral epiphyses was analysed. K-wires were used for fixation in 4 hips each therapeutically and prophylactically, 22 hips with SCFE and 14 non-affected hips were stabilised with screws. Treatment with screws did not lead to significantly earlier physeal closure than k-wire pinning. Regarding the femoral growth parameters a significant decrease in the articulo-trochanteric distance and CCD angle was detectable in all groups. The pin-joint ratio revealed an adequate residual growth in 58 % of the therapeutically and in 72 % of the prophylactically treated hips without significant difference between k-wires and screws. The pin-physis ratio demonstrated similar values. Regarding the femoral deformity the SCFE hips resulted in a significantly reduced sphericity, which remained unchanged during follow-up. The

  20. Slipped Capital Femoral Epiphysis as a Complication of Growth Hormone Therapy

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    Shuo-Yu Wang

    2007-01-01

    Full Text Available Slipped capital femoral epiphysis (SCFE is a rare complication of growth hormone (GH therapy. Here, we report three patients who developed SCFE during GH therapy. The first two patients had hypopituitarism and had started GH therapy at the age of 15 years 6 months and 13 years 9 months, respectively. SCFE developed 4 years and 1 year after GH therapy, respectively. The third patient had Prader-Willi syndrome with obesity and hypogonadism and began GH therapy at the age of 12 years and 11 months. SCFE developed 2 months after starting GH therapy. Pain over the hip joints or over the knees is an early sign of SCFE. Despite recommendation, none of the three patients continued GH therapy. A high index of suspicion during GH therapy in patients at high risk of SCFE is important for early diagnosis and appropriate management. [J Formos Med Assoc 2007;106(2 Suppl:S46-S50

  1. Biomechanical considerations in slipped capital femoral epiphysis and insights into prophylactic fixation.

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    Leblanc, E; Bellemore, J M; Cheng, T; Little, D G; Birke, O

    2017-04-01

    Slipped capital femoral epiphysis (SCFE) is a deformity of the proximal femur secondary to widened and unstable physis. In stabilising the slip, gold standard treatments stop growth and involve premature physeal closure, which prevents the remodelling of the acquired deformity and creates a leg length discrepancy that may be significant in younger patients. We measured the impact of placing threaded screws across the proximal femoral physis by measuring the centre-trochanteric distance (CTD) and articulo-trochanteric distance (ATD) in participants with or without prophylactic fixation. We then compared the mechanical performance of static (stainless and titanium cannulated Synthes screws) and potentially growing implants (Synthes SCFE screw and Pega Medical Free Gliding screw) in a validated synthetic bone model. In the review of 30 non-fixed and 60 fixated hips over a mean follow-up of 1.9 years, we have noted a significant difference in pre/post CTD and ATD, as well as the change in CTD and ATD over time. In the biomechanical study, the newer implants allowing growth (Synthes SCFE screw and Pega Medical Free Gliding screw) were both shown to be at least non-inferior. The primary deformity of a SCFE in itself alters hip mechanics. Also, as confirmed in this study, there is a secondary deformity that is created by static fixation and relative trochanteric overgrowth. To help remodel mild deformities and prevent secondary trochanteric overgrowth, growing implants seem to be non-inferior to the more standard means of fixation in static testing.

  2. The role of pre-treatment MRI in established cases of slipped capital femoral epiphysis

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    Tins, Bernhard; Cassar-Pullicino, Victor; McCall, Iain

    2009-01-01

    Background: Slipped capital femoral epiphysis (SCFE) often results in functional impairment and premature osteoarthritis despite surgical treatment. Treatment decisions are commonly based on the clinical history and radiographic appearance. This study assesses the pre-treatment features of SCFE and correlates them to the clinical history to: (1) define the underlying pathological mechanisms; (2) correlate the morphological hip abnormalities with the clinical classifications; (3) identify specific magnetic resonance imaging (MRI) features that could carry prognostic implications for treatment approach and outcome. Methods: Clinical history and pre- and posttreatment radiographs and pre-treatment MRIs of 14 patients with 15 affected hips were reviewed. Alignment, impingement, fulcrum formation, remodelling, osteopenia, synovitis, joint effusion, bone marrow and soft tissue oedema and status of the physis and the periosteal sleeve were assessed and related to the clinical history, in particular history of trauma, duration of clinical symptoms and ability to bear weight. Results: Bone marrow oedema around the growth plate and joint effusion occurred in all patients. Synovitis occurred in 13/15 patients. 6 patients had a fall before presenting with SCFE. 5/6 had periarticular soft tissue oedema, complete disruption of the physis and partial periosteal sleeve disruption. 9 patients had no fall prior to presentation, physis and periost were intact in 7/9; periarticular oedema was not seen. 14/15 showed evidence of chronic remodelling. Despite an acute clinical history remodelling was present. A fulcrum-like alignment, impingement of the epiphysis on the metaphysis with a small area of physical contact, was seen in 8 patients, 6/8 had a prior fall. There was no case of avascular necrosis. Spontaneous reduction of SCFE occurred in 1 case, the only case without chronic remodelling. With MRI as gold standard radiographs underestimate the severity of SCFE. Conclusion

  3. The role of pre-treatment MRI in established cases of slipped capital femoral epiphysis

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    Tins, Bernhard [Department of Radiology, Robert Jones and Agnes Hunt Orthopaedic and District Hospital, Oswestry, Shropshire SY 10 7 AG (United Kingdom)], E-mail: Bernhard.Tins@rjah.nhs.uk; Cassar-Pullicino, Victor; McCall, Iain [Department of Radiology, Robert Jones and Agnes Hunt Orthopaedic and District Hospital, Oswestry, Shropshire SY 10 7 AG (United Kingdom)

    2009-06-15

    Background: Slipped capital femoral epiphysis (SCFE) often results in functional impairment and premature osteoarthritis despite surgical treatment. Treatment decisions are commonly based on the clinical history and radiographic appearance. This study assesses the pre-treatment features of SCFE and correlates them to the clinical history to: (1) define the underlying pathological mechanisms; (2) correlate the morphological hip abnormalities with the clinical classifications; (3) identify specific magnetic resonance imaging (MRI) features that could carry prognostic implications for treatment approach and outcome. Methods: Clinical history and pre- and posttreatment radiographs and pre-treatment MRIs of 14 patients with 15 affected hips were reviewed. Alignment, impingement, fulcrum formation, remodelling, osteopenia, synovitis, joint effusion, bone marrow and soft tissue oedema and status of the physis and the periosteal sleeve were assessed and related to the clinical history, in particular history of trauma, duration of clinical symptoms and ability to bear weight. Results: Bone marrow oedema around the growth plate and joint effusion occurred in all patients. Synovitis occurred in 13/15 patients. 6 patients had a fall before presenting with SCFE. 5/6 had periarticular soft tissue oedema, complete disruption of the physis and partial periosteal sleeve disruption. 9 patients had no fall prior to presentation, physis and periost were intact in 7/9; periarticular oedema was not seen. 14/15 showed evidence of chronic remodelling. Despite an acute clinical history remodelling was present. A fulcrum-like alignment, impingement of the epiphysis on the metaphysis with a small area of physical contact, was seen in 8 patients, 6/8 had a prior fall. There was no case of avascular necrosis. Spontaneous reduction of SCFE occurred in 1 case, the only case without chronic remodelling. With MRI as gold standard radiographs underestimate the severity of SCFE. Conclusion

  4. Evaluation of femoral head vascularization in slipped capital femoral epiphysis before and after cannulated screw fixation with use of contrast-enhanced MRI: initial results

    International Nuclear Information System (INIS)

    Staatz, G.; Honnef, D.; Hohl, C.; Schmidt, T.; Guenther, R.W.; Kochs, A.; Roehrig, H.

    2007-01-01

    In this study we used contrast-enhanced magnetic resonance imaging (MRI) to evaluate the vascularization of the femoral head in children with slipped capital femoral epiphysis (SCFE) before and after cannulated screw fixation. Eleven consecutive children with SCFE, seven boys and four girls, aged 10-15 years were included in the study. There were no preslips; four children had acute, three acute-on-chronic, and four chronic SCFE. The MRI examinations were performed in a 1.5 Tesla MR scanner with use of a coronal STIR sequence, a coronal contrast-enhanced T1-weighted spin-echo sequence, and a sagittal three-dimensional gradient-echo sequence. Morphology, signal intensities, and contrast-enhancement of the femoral head were assessed by two radiologists in consensus. Morphologic distortion of the physis, bone marrow edema within the metaphysis and epiphysis, and joint effusion were the preoperative MRI findings of SCFE in each child. In nine children, the vascularization of the femoral head before and after surgery was normal. In one child, a preoperative avascular zone in the superolateral aspect of the epiphysis revascularized completely after surgery. One child with severe SCFE developed avascular necrosis of the femoral head after open reduction of the slip. We conclude that MRI allows for accurate evaluation of the femoral head vascularization before and after surgery in children with SCFE. (orig.)

  5. Evaluation of femoral head vascularization in slipped capital femoral epiphysis before and after cannulated screw fixation with use of contrast-enhanced MRI: initial results

    Energy Technology Data Exchange (ETDEWEB)

    Staatz, G. [Friedrich-Alexander-University Erlangen-Nuernberg, Department of Radiology, Division of Pediatric Radiology, Erlangen (Germany); University Hospital of the RWTH Aachen, Department of Diagnostic Radiology, Aachen (Germany); Honnef, D.; Hohl, C.; Schmidt, T.; Guenther, R.W. [University Hospital of the RWTH Aachen, Department of Diagnostic Radiology, Aachen (Germany); Kochs, A.; Roehrig, H. [University Hospital of the RWTH Aachen, Department of Orthopaedic Surgery, Aachen (Germany)

    2007-01-15

    In this study we used contrast-enhanced magnetic resonance imaging (MRI) to evaluate the vascularization of the femoral head in children with slipped capital femoral epiphysis (SCFE) before and after cannulated screw fixation. Eleven consecutive children with SCFE, seven boys and four girls, aged 10-15 years were included in the study. There were no preslips; four children had acute, three acute-on-chronic, and four chronic SCFE. The MRI examinations were performed in a 1.5 Tesla MR scanner with use of a coronal STIR sequence, a coronal contrast-enhanced T1-weighted spin-echo sequence, and a sagittal three-dimensional gradient-echo sequence. Morphology, signal intensities, and contrast-enhancement of the femoral head were assessed by two radiologists in consensus. Morphologic distortion of the physis, bone marrow edema within the metaphysis and epiphysis, and joint effusion were the preoperative MRI findings of SCFE in each child. In nine children, the vascularization of the femoral head before and after surgery was normal. In one child, a preoperative avascular zone in the superolateral aspect of the epiphysis revascularized completely after surgery. One child with severe SCFE developed avascular necrosis of the femoral head after open reduction of the slip. We conclude that MRI allows for accurate evaluation of the femoral head vascularization before and after surgery in children with SCFE. (orig.)

  6. Demographics and clinical presentation of slipped capital femoral epiphysis in Singapore: comparing the East with the West.

    Science.gov (United States)

    Lim, Yi-Jia; Kagda, Fareed; Lam, Khee Sien; Hui, James H P; Lim, Kevin B L; Mahadev, Arjandas; Lee, Eng Hin

    2008-11-01

    This study examines the demographics and clinical presentation of slipped capital femoral epiphysis in Singapore. Sixty-six patients (53 boys, 13 girls) with 77 involved hips were reviewed retrospectively. Local prevalence was 1.2/100,000 children. Twenty-four patients were Chinese, 12 were Malay, 27 were Indians, and three patients were Eurasians. A total of 76.6% of patients above the 90th percentile for body weight were present; 16.7% of patients had bilateral involvement. Seventeen patients had endocrine-related problems. We had a high male preponderance, and a disproportionately high number of Indian patients. A high proportion of patients were obese. Our incidence of bilateral involvement seems to be higher than our Indonesian neighbors. The differences seen may be due to genetic and sociocultural variations.

  7. Closed reduction of slipped capital femoral epiphysis: high-risk factor for avascular necrosis.

    Science.gov (United States)

    Kitano, Toshio; Nakagawa, Keisuke; Wada, Mayuko; Moriyama, Michiko

    2015-07-01

    How should we treat acute/unstable slipped capital femoral epiphysis (SCFE) without the development of avascular necrosis (AVN)? To answer this question, we investigated the risk factors of AVN development after SCFE. Seventy-six hips of 64 patients were classified using two kinds of classification systems, Loder's classification based on instability and the conventional classification based on the duration of symptom, because both classifications are related to AVN development. Of 21 unstable SCFEs, seven hips developed AVN. Of 35 hips defined as acute or acute on chronic, nine hips developed AVN. Two stable SCFEs of Loder's classification developed AVN, one was acute and the other was acute on chronic. No hips of chronic SCFE developed AVN. The factor that had influenced AVN development was only closed reduction, whether purposefully or inadvertently, in an acute or unstable SCFE. On the basis of the findings of this study, one should not embark on any modality of closed reduction for an unstable or acute form of SCFE, as there is a high risk for occurrence of AVN. For the same reason, a traction table should not be used for SCFE fixation, so as to avoid an inadvertent reduction or force that can lead to AVN.

  8. Delay in the Diagnosis of Stable Slipped Capital Femoral Epiphysis.

    Science.gov (United States)

    Hosseinzadeh, Pooya; Iwinski, Henry J; Salava, Jonathon; Oeffinger, Donna

    2017-01-01

    Delays in the diagnosis of stable slipped capital femoral epiphysis (SCFE) is common due to the vague symptomatology and the lack of awareness of this entity by healthcare providers. Delays in the diagnosis of this condition can lead to poor outcomes for the patients. This study was designed to identify factors that contributed to delays in the diagnosis or the treatment of patients with SCFE seen at our institution. A retrospective chart review of patients with the diagnosis of a stable SCFE who had undergone screw stabilization between 1989 and 2010 at our hospital was performed. For each patient, demographic data, the date of initial onset of symptoms, the date of the first visit to the medical provider, the type of provider seen initially (orthopaedic surgeon or not), the date of diagnosis of SCFE, the type of physician who made the diagnosis (orthopaedic surgeon or not), and the date of surgery were recorded. For each patient, the presenting symptom was recorded as hip, thigh, or knee pain. The effect of demographic data, presenting symptoms, and the type of initial provider seen on the delay to diagnosis was studied using 2 Cox models. A total of 149 patients with 196 stable SCFE were included. The average time from the first physician visit to diagnosis was 94 days in the group seen by a nonorthopaedic provider compared with an average of 2.9 days in the group seen by an orthopaedist (Pprovider versus 97% in the group seen by orthopaedic surgeons. It took significantly longer to be diagnosed with SCFE in patients who presented with initial knee pain (P=0.0097) compared with those who presented with hip pain at the initial visit. This study shows a significant delay in the diagnosis of SCFE in the United States, particularly in patients seen by nonorthopaedic providers initially. Level III-prognostic.

  9. Canadian capital spending to slip 4.7% in 1993

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Total capital and exploration spending by the Canadian petroleum industry is estimated at $6.579 billion in 1993, a drop of 4.7% from estimated 1992 outlays. Last year Canadian capital spending of $6.9 billion represented a drop of 8.9% from 1991 outlays, according to an Oil and Gas Journal survey. All survey related spending estimates in this paper are in U.S. dollars. All individual company spending estimates are in Canadian dollars

  10. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), after slipped capital femoral epiphysis

    Energy Technology Data Exchange (ETDEWEB)

    Zilkens, Christoph, E-mail: Christoph.Zilkens@med.uni-duesseldorf.de [Department of Orthopaedics, Heinrich-Heine University Medical School, Moorenstrasse 5, 40225 Duesseldorf (Germany); Miese, Falk [Department of Radiology, Heinrich-Heine University Medical School, Moorenstrasse 5, 40225 Duesseldorf (Germany); Bittersohl, Bernd; Jaeger, Marcus; Schultz, Johannes [Department of Orthopaedics, Heinrich-Heine University Medical School, Moorenstrasse 5, 40225 Duesseldorf (Germany); Holstein, Arne [Department of Radiology, Heinrich-Heine University Medical School, Moorenstrasse 5, 40225 Duesseldorf (Germany); Kim, Young-jo; Millis, Michael B. [Department of Orthopaedic Surgery, Childrens Hospital Boston, Harvard Medical, School, 300 Longwood Avenue, Boston, MA 02115 (United States); Mamisch, Tallal C. [Department of Orthopaedic Surgery, Inselspital Bern, University Hospital, Bern (Switzerland); Krauspe, Ruediger [Department of Orthopaedics, Heinrich-Heine University Medical School, Moorenstrasse 5, 40225 Duesseldorf (Germany)

    2011-09-15

    Objective: The aim of this study was to assess the glycosaminoglycan (GAG) content in hip joint cartilage in mature hips with a history of slipped capital femoral epiphysis (SCFE) using delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). Methods: 28 young-adult subjects (32 hips) with a mean age of 23.8 {+-} 4.0 years (range: 18.1-30.5 years) who were treated for mild or moderate SCFE in adolescence were included into the study. Hip function and clinical symptoms were evaluated with the Harris hip score (HHS) system at the time of MRI. Plain radiographic evaluation included Tonnis grading, measurement of the minimal joint space width (JSW) and alpha-angle measurement. The alpha-angle values were used to classify three sub-groups: group 1 = subjects with normal femoral head-neck offset (alpha-angle <50{sup o}), group 2 = subjects with mild offset decrease (alpha-angle 50{sup o}-60{sup o}), and group 3 = subjects with severe offset decrease (alpha-angle >60{sup o}). Results: There was statistically significant difference noted for the T1{sub Gd} values, lateral and central, between group 1 and group 3 (p-values = 0.038 and 0.041). The T1{sub Gd} values measured within the lateral portion were slightly lower compared with the T1{sub Gd} values measured within the central portion that was at a statistically significance level (p-value <0.001). HHS, Tonnis grades and JSW revealed no statistically significant difference. Conclusion: By using dGEMRIC in the mid-term follow-up of SCFE we were able to reveal degenerative changes even in the absence of joint space narrowing that seem to be related to the degree of offset pathology. The dGEMRIC technique may be a potential diagnostic modality in the follow-up evaluation of SCFE.

  11. A Kinematic Model of Slow Slip Constrained by Tremor-Derived Slip Histories in Cascadia

    Science.gov (United States)

    Schmidt, D. A.; Houston, H.

    2016-12-01

    We explore new ways to constrain the kinematic slip distributions for large slow slip events using constraints from tremor. Our goal is to prescribe one or more slip pulses that propagate across the fault and scale appropriately to satisfy the observations. Recent work (Houston, 2015) inferred a crude representative stress time history at an average point using the tidal stress history, the static stress drop, and the timing of the evolution of tidal sensitivity of tremor over several days of slip. To convert a stress time history into a slip time history, we use simulations to explore the stressing history of a small locked patch due to an approaching rupture front. We assume that the locked patch releases strain through a series of tremor bursts whose activity rate is related to the stressing history. To test whether the functional form of a slip pulse is reasonable, we assume a hypothetical slip time history (Ohnaka pulse) timed with the occurrence of tremor to create a rupture front that propagates along the fault. The duration of the rupture front for a fault patch is constrained by the observed tremor catalog for the 2010 ETS event. The slip amplitude is scaled appropriately to match the observed surface displacements from GPS. Through a forward simulation, we evaluate the ability of the tremor-derived slip history to accurately predict the pattern of surface displacements observed by GPS. We find that the temporal progression of surface displacements are well modeled by a 2-4 day slip pulse, suggesting that some of the longer duration of slip typically found in time-dependent GPS inversions is biased by the temporal smoothing. However, at some locations on the fault, the tremor lingers beyond the passage of the slip pulse. A small percentage (5-10%) of the tremor appears to be activated ahead of the approaching slip pulse, and tremor asperities experience a driving stress on the order of 10 kPa/day. Tremor amplitude, rather than just tremor counts, is needed

  12. Slip initiation in alternative and slip-resistant footwear.

    Science.gov (United States)

    Chander, Harish; Wade, Chip; Garner, John C; Knight, Adam C

    2017-12-01

    Slips occur as a result of failure of normal locomotion. The purpose of this study is to analyze the impact of alternative footwear (Crocs™, flip-flops) and an industry standard low-top slip-resistant shoe (SRS) under multiple gait trials (normal dry, unexpected slip, alert slip and expected slip) on lower extremity joint kinematics, kinetics and muscle activity. Eighteen healthy male participants (age: 22.28 ± 2.2 years; height: 177.66 ± 6.9 cm; mass: 79.27 ± 7.6 kg) completed the study. Kinematic, kinetic and muscle activity variables were analyzed using a 3(footwear) × 4(gait trials) repeated-measures analysis of variance at p = 0.05. Greater plantar flexion angles, lower ground reaction forces and greater muscle activity were seen on slip trials with the alternative footwear. During slip events, SRS closely resembled normal dry biomechanics, suggesting it to be a safer footwear choice compared with alternative footwear.

  13. How informative are slip models for aftershock forecasting?

    Science.gov (United States)

    Bach, Christoph; Hainzl, Sebastian

    2013-04-01

    Coulomb stress changes (ΔCFS) have been recognized as a major trigger mechanism for earthquakes, in particular aftershock distributions and the spatial patterns of ΔCFS are often found to be correlated. However, the Coulomb stress calculations are based on slip inversions and the receiver fault mechanisms which both contain large uncertainties. In particular, slip inversions are usually non-unique and often differ strongly for the same earthquakes. Here we want to address the information content of those inversions with respect to aftershock forecasting. Therefore we compare the slip models to randomized fractal slip models which are only constrained by fault information and moment magnitude. The uncertainty of the aftershock mechanisms is considered by using many receiver fault orientations, and by calculating ΔCFS at several depth layers. The stress change is then converted into an aftershock probability map utilizing a clock advance model. To estimate the information content of the slip models, we use an Epidemic Type Aftershock Sequence (ETAS) model approach introduced by Bach and Hainzl (2012), where the spatial probability density of direct aftershocks is related to the ΔCFS calculations. Besides the directly triggered aftershocks, this approach also takes secondary aftershock triggering into account. We quantify our results by calculating the information gain of the randomized slip models relative to the corresponding published slip model. As case studies, we investigate the aftershock sequences of several well-known main shocks such as 1992 Landers, 1999 Hector Mine, 2004 Parkfield, 2002 Denali. First results show a huge difference in the information content of slip models. For some of the cases up to 90% of the random slip models are found to perform better than the originally published model, for some other cases only few random models are found performing better than the published slip model.

  14. Transtrochanteric rotational osteotomy for avascular necrosis of the femoral head after unstable slipped capital femoral epiphysis: 10-year clinical results.

    Science.gov (United States)

    Nakashima, Yasuharu; Yamamoto, Takuaki; Fukushi, Jun-Ichi; Motomura, Goro; Hamai, Satoshi; Kohno, Yusuke; Iwamoto, Yukihide

    2016-11-01

    Avascular necrosis of the femoral head (AVN) is the most serious complication after unstable slipped capital femoral epiphysis (SCFE), and is often unsalvageable. We report a minimum 10 years of clinical results for transtrochanteric rotational osteotomy of the femoral head (TRO) for AVN. This study included 7 patients (7 hips) with a mean age at surgery of 13.3 years, and the follow-up period was 15.8 years. All patients had prior treatment via closed reduction and pinning of the unstable SCFE, and showed severely collapsed femoral heads. The direction of rotation was anterior in 3 hips and posterior in 4. The Merle d'Aubigné-Postel score (MDPS) was used for clinical assessment, and joint degeneration was assessed with the Kellgren and Lawrence classification (KL-grade). The spherical intact area of the femoral head was moved to the weight-bearing portion, and subluxation was corrected via rotation combined with intentional varus positioning. The mean MDPS improved from 10.3 points to 15.6 points at 5 years, and it was maintained at 15.0 points by 10 years; 3 hips were excellent, 1 was good, 2 were fair, and 1 showed poor outcomes. No patient experienced re-collapse after TRO or required conversion to hip replacement or arthrodesis. After 10 years, degenerative changes became evident over time, and 2 hips progressed to KL-4 with a decreased MDPS. Although some joint degeneration is inevitable in the long-term, TRO is an effective salvage procedure for treating AVN after unstable SCFE. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

  15. Duration of slip-resistant shoe usage and the rate of slipping in limited-service restaurants: results from a prospective and crossover study.

    Science.gov (United States)

    Verma, Santosh K; Zhao, Zhe; Courtney, Theodore K; Chang, Wen-Ruey; Lombardi, David A; Huang, Yueng-Hsiang; Brennan, Melanye J; Perry, Melissa J

    2014-01-01

    Several studies have indicated that slip-resistant shoes may have a positive effect on reducing the risk of slips and falls, a leading cause of injury at work. Few studies, however, have examined how duration of shoe usage affects their slip-resistance properties. This study examined the association between the duration of slip-resistant shoes usage and the self-reported rate of slipping in limited-service restaurant workers. A total of 475 workers from 36 limited-service restaurants in the USA were recruited to participate in a 12-week prospective study of workplace slipping. Of the 475 participants, 83 reported changing to a new pair of shoes at least once during the 12-week follow-up. The results show that slip-resistant shoes worn for less than six months were moderately more effective than those worn for more than six months. Changing to a new pair of shoes among those wearing slip-resistant shoes at baseline was associated with a 55% reduction in the rate of slipping (RR = 0.45, 95% CI = 0.23-0.89). Further research is needed to develop criteria for the replacement of slip-resistant shoes.

  16. What causes an icy fault to slip? Investigating strike-slip failure conditions on Ganymede at Dardanus and Tiamat Sulcus.

    Science.gov (United States)

    Cameron, M. E.; Smith-Konter, B. R.; Burkhard, L. M.; Collins, G. C.; Seifert, F.; Pappalardo, R. T.

    2015-12-01

    Ganymede exhibits two geologically distinct terrains known as dark and light (grooved) terrain. The mechanism for a transition from dark to light terrain remains unclear; however, inferences of strike-slip faulting and distributed shear zones suggest that strike-slip tectonism may be important to the structural development of Ganymede's surface and in this transition. Here we investigate the role of tidal stresses on Ganymede in the formation and evolution of strike-slip structures in both dark and grooved terrains. Using numerical code SatStress, we calculate both diurnal and non-synchronous rotation (NSR) tidal stresses at Ganymede's surface. Specifically, we investigate the role of fault friction and orbital eccentricity in the development of ~45 km of right-lateral offset at Dardanus Sulcus and a possible case of study with a detailed morphological mapping of strike-slip morphologies (en echelon structures, strike-slip duplexes, laterally offset pre-existing features, and possible strained craters) at Nun Sulcus and several other locations. These structures serve as example regions to provide improved constraints for global stress mechanisms responsible for strike-slip fault evolution on Ganymede.

  17. Early diagnosis of slipped capital femoral epiphysis on magnetic resonance imaging: A case report with review of literature

    Directory of Open Access Journals (Sweden)

    Sanjay M Khaladkar

    2015-01-01

    Full Text Available Slipped capital femoral epiphysis (SCFE is a common hip condition occurring in adolescents, with a prevalence of 10 cases per 100,000 children. It usually affects younger age group from 10 to 17 years. The condition is usually found to be coexistent with various other conditions such as obesity, growth surges, and endocrine disorders such as hypothyroidism, growth hormone supplementation, hypogonadism, and pan-hypopituitarism. Patients present with limping and a poorly localized pain in the hip, groin, thigh, or knee. Diagnosis of the condition is often delayed due to its nonassociation with trauma and hence increases the chances of developing various complications such as avascular necrosis, chondrolysis and deformity. Majority of researches of SCFE are from Europe and North America, while studies in Asian populations are rare. Delay in diagnosis of SCFE is usually due to patients presenting with knee pain. Imaging can thus aid in early diagnosis and appropriate treatment of the disease, which in turn reduces incidence of deformity and disability in the affected children. Bilateral hip radiography - anteroposterior and frog′s-leg lateral views and magnetic resonance imaging (MRI are the radiological techniques that help in early diagnosis. MRI detects early physeal changes of both preslip and SCFE even when radiographs and computed tomography are normal. MRI should be routinely used to diagnose early SCFE in preslip stage to avoid further complications.

  18. Learning and Prediction of Slip from Visual Information

    Science.gov (United States)

    Angelova, Anelia; Matthies, Larry; Helmick, Daniel; Perona, Pietro

    2007-01-01

    This paper presents an approach for slip prediction from a distance for wheeled ground robots using visual information as input. Large amounts of slippage which can occur on certain surfaces, such as sandy slopes, will negatively affect rover mobility. Therefore, obtaining information about slip before entering such terrain can be very useful for better planning and avoiding these areas. To address this problem, terrain appearance and geometry information about map cells are correlated to the slip measured by the rover while traversing each cell. This relationship is learned from previous experience, so slip can be predicted remotely from visual information only. The proposed method consists of terrain type recognition and nonlinear regression modeling. The method has been implemented and tested offline on several off-road terrains including: soil, sand, gravel, and woodchips. The final slip prediction error is about 20%. The system is intended for improved navigation on steep slopes and rough terrain for Mars rovers.

  19. External debt and capital flight in Nigeria: Is there a revolving door?

    Directory of Open Access Journals (Sweden)

    OT Ajilore

    2014-10-01

    Full Text Available Using the residual method of capital flight estimation, this paper estimates Nigerian capital flight over the period 1970 - 2001 and finds a close correlation between external debt and capital flight flows. This phenomenon suggests a paradoxical revolving door of a bi-directional flow of capital, i.e. where capital enters the country in the guise of external borrowing and simultaneously slips out of the country as private capital flight. The research question addressed by this paper is whether such a financial revolving door relationship exists in Nigeria, just as previous empirical researches had established in a number of countries. The paper utilises a simultaneous equation model and three stage least square estimation technique (3SLS, in addition to two-way Granger causality tests, to obtain statistical evidence that confirms the existence of a financial revolving door relationship between the two endogenous variables. In addition, existence of stronger causality from debt to capital flight is instrumental in showing that growing public deficit and the resulting increase in external debt is being used as a transfer mechanism for capital flight.

  20. Stick-slip friction and wear of articular joints

    Science.gov (United States)

    Lee, Dong Woog; Banquy, Xavier; Israelachvili, Jacob N.

    2013-01-01

    Stick-slip friction was observed in articular cartilage under certain loading and sliding conditions and systematically studied. Using the Surface Forces Apparatus, we show that stick-slip friction can induce permanent morphological changes (a change in the roughness indicative of wear/damage) in cartilage surfaces, even under mild loading and sliding conditions. The different load and speed regimes can be represented by friction maps—separating regimes of smooth and stick-slip sliding; damage generally occurs within the stick-slip regimes. Prolonged exposure of cartilage surfaces to stick-slip sliding resulted in a significant increase of surface roughness, indicative of severe morphological changes of the cartilage superficial zone. To further investigate the factors that are conducive to stick-slip and wear, we selectively digested essential components of cartilage: type II collagen, hyaluronic acid (HA), and glycosaminoglycans (GAGs). Compared with the normal cartilage, HA and GAG digestions modified the stick-slip behavior and increased surface roughness (wear) during sliding, whereas collagen digestion decreased the surface roughness. Importantly, friction forces increased up to 2, 10, and 5 times after HA, GAGs, and collagen digestion, respectively. Also, each digestion altered the friction map in different ways. Our results show that (i) wear is not directly related to the friction coefficient but (ii) more directly related to stick-slip sliding, even when present at small amplitudes, and that (iii) the different molecular components of joints work synergistically to prevent wear. Our results also suggest potential noninvasive diagnostic tools for sensing stick-slip in joints. PMID:23359687

  1. Effective slip lengths for flows over surfaces with nanobubbles: the effects of finite slip

    International Nuclear Information System (INIS)

    Hendy, S C; Lund, N J

    2009-01-01

    We consider effective slip lengths for flows of simple liquids over surfaces contaminated by gaseous nanobubbles. In particular, we examine whether the effects of finite slip over the liquid-bubble interface are important in limiting effective slip lengths over such surfaces. Using an expression that interpolates between the perfect slip and finite slip regimes for flow over bubbles, we conclude that for the bubble dimensions and coverages typically reported in the literature the effects of finite slip are secondary, reducing effective slip lengths by only 10%. Further, we find that nanobubbles do not significantly increase slip lengths beyond those reported for bare hydrophobic surfaces.

  2. Evidence for slip partitioning and bimodal slip behavior on a single fault: Surface slip characteristics of the 2013 Mw7.7 Balochistan, Pakistan earthquake

    Science.gov (United States)

    Barnhart, William; Briggs, Richard; Reitman, Nadine G.; Gold, Ryan D.; Hayes, Gavin

    2015-01-01

    Deformation is commonly accommodated by strain partitioning on multiple, independent strike-slip and dip-slip faults in continental settings of oblique plate convergence. As a corollary, individual faults tend to exhibit one sense of slip – normal, reverse, or strike-slip – until whole-scale changes in boundary conditions reactivate preexisting faults in a new deformation regime. In this study, we show that a single continental fault may instead partition oblique strain by alternatively slipping in a strike-slip or a dip-slip sense during independent fault slip events. We use 0.5 m resolution optical imagery and sub-pixel correlation analysis of the 200+ km 200+km"> 2013 Mw7.7 Balochistan, Pakistan earthquake to document co-seismic surface slip characteristics and Quaternary tectonic geomorphology along the causative Hoshab fault. We find that the 2013 earthquake, which involved a ∼6:1 strike-slip to dip-slip ratio, ruptured a structurally segmented fault. Quaternary geomorphic indicators of gross fault-zone morphology reveal both reverse-slip and strike-slip deformation in the rupture area of the 2013 earthquake that varies systematically along fault strike despite nearly pure strike-slip motion in 2013. Observations of along-strike variations in range front relief and geomorphic offsets suggest that the Hoshab fault accommodates a substantial reverse component of fault slip in the Quaternary, especially along the southern section of the 2013 rupture. We surmise that Quaternary bimodal slip along the Hoshab fault is promoted by a combination of the arcuate geometry of the Hoshab fault, the frictional weakness of the Makran accretionary prism, and time variable loading conditions from adjacent earthquakes and plate interactions.

  3. The influence of slip velocity and temperature on permeability during and after high-velocity fault slip

    Science.gov (United States)

    Tanikawa, W.; Mukoyoshi, H.; Tadai, O.; Hirose, T.; Lin, W.

    2011-12-01

    Fluid transport properties in fault zones play an important role in dynamic processes during large earthquakes. If the permeability in a fault zone is low, high pore-fluid pressures caused by thermal pressurization (Sibson, 1973) or shear-induced compaction (Blanpied et al., 1992) can lead to an apparent reduction of fault strength. Changes in porosity and permeability of fault rocks within a fault zone during earthquakes and the subsequent progressive recovery of these properties may have a large influence on earthquake recurrence (Sleep and Blanpied, 1992). A rotary shear apparatus was used to investigate changes of fluid transport properties in a fault zone by real-time measurement of gas flow rates during and after shearing of hollow sandstone and granite cylinders at various slip rates. Our apparatus measures permeability parallel to the slip plane in both the slip zone and wall rocks. In all cases, permeability decreased rapidly with an increase of friction, but recovered soon after slip, reaching a steady state within several tens of minutes. The rate of reduction of permeability increased with increasing slip velocity. Permeability did not recover to pre-slip levels after low-velocity tests but recovered to exceed them after high-velocity tests. Frictional heating of gases at the slip surface increased gas viscosity, which increased gas flow rate to produce an apparent permeability increase. The irreversible permeability changes of the low-velocity tests were caused by gouge formation due to wearing and smoothing of the slip surface. The increase of permeability after high-velocity tests was caused by mesoscale fracturing in response to rapid temperature rise. Changes of pore fluid viscosity contributed more to changes of flow rate than did permeability changes caused by shear deformation, although test results from different rocks and pore fluids might be different. References Blanpied, M.L., Lockner, D.A., Byerlee, J.D., 1992. An earthquake mechanism

  4. Slipping on pedestrian surfaces: methods for measuring and evaluating the slip resistance.

    Science.gov (United States)

    Wetzel, Christoph; Windhövel, Ulrich; Mewes, Detlef; Ceylan, Orhan

    2015-01-01

    Tripping, slipping and falling accidents are among the types of accident with a high incidence. This article describes the requirements concerning slip resistance, as well as the state of the art of slip resistance measurement standards in the European Community and the USA. The article also describes how risk assessment can be performed in the field.

  5. States of stress and slip partitioning in a continental scale strike-slip duplex: Tectonic and magmatic implications by means of finite element modeling

    Science.gov (United States)

    Iturrieta, Pablo Cristián; Hurtado, Daniel E.; Cembrano, José; Stanton-Yonge, Ashley

    2017-09-01

    Orogenic belts at oblique convergent subduction margins accommodate deformation in several trench-parallel domains, one of which is the magmatic arc, commonly regarded as taking up the margin-parallel, strike-slip component. However, the stress state and kinematics of volcanic arcs is more complex than usually recognized, involving first- and second-order faults with distinctive slip senses and mutual interaction. These are usually organized into regional scale strike-slip duplexes, associated with both long-term and short-term heterogeneous deformation and magmatic activity. This is the case of the 1100 km-long Liquiñe-Ofqui Fault System in the Southern Andes, made up of two overlapping margin-parallel master faults joined by several NE-striking second-order faults. We present a finite element model addressing the nature and spatial distribution of stress across and along the volcanic arc in the Southern Andes to understand slip partitioning and the connection between tectonics and magmatism, particularly during the interseismic phase of the subduction earthquake cycle. We correlate the dynamics of the strike-slip duplex with geological, seismic and magma transport evidence documented by previous work, showing consistency between the model and the inferred fault system behavior. Our results show that maximum principal stress orientations are heterogeneously distributed within the continental margin, ranging from 15° to 25° counter-clockwise (with respect to the convergence vector) in the master faults and 10-19° clockwise in the forearc and backarc domains. We calculate the stress tensor ellipticity, indicating simple shearing in the eastern master fault and transpressional stress in the western master fault. Subsidiary faults undergo transtensional-to-extensional stress states. The eastern master fault displays slip rates of 5 to 10 mm/yr, whereas the western and subsidiary faults show slips rates of 1 to 5 mm/yr. Our results endorse that favorably oriented

  6. Quantifying slip balance in the earthquake cycle: Coseismic slip model constrained by interseismic coupling

    KAUST Repository

    Wang, Lifeng; Hainzl, Sebastian; Mai, Paul Martin

    2015-01-01

    The long-term slip on faults has to follow, on average, the plate motion, while slip deficit is accumulated over shorter time scales (e.g., between the large earthquakes). Accumulated slip deficits eventually have to be released by earthquakes and aseismic processes. In this study, we propose a new inversion approach for coseismic slip, taking interseismic slip deficit as prior information. We assume a linear correlation between coseismic slip and interseismic slip deficit, and invert for the coefficients that link the coseismic displacements to the required strain accumulation time and seismic release level of the earthquake. We apply our approach to the 2011 M9 Tohoku-Oki earthquake and the 2004 M6 Parkfield earthquake. Under the assumption that the largest slip almost fully releases the local strain (as indicated by borehole measurements, Lin et al., 2013), our results suggest that the strain accumulated along the Tohoku-Oki earthquake segment has been almost fully released during the 2011 M9 rupture. The remaining slip deficit can be attributed to the postseismic processes. Similar conclusions can be drawn for the 2004 M6 Parkfield earthquake. We also estimate the required time of strain accumulation for the 2004 M6 Parkfield earthquake to be ~25 years (confidence interval of [17, 43] years), consistent with the observed average recurrence time of ~22 years for M6 earthquakes in Parkfield. For the Tohoku-Oki earthquake, we estimate the recurrence time of~500-700 years. This new inversion approach for evaluating slip balance can be generally applied to any earthquake for which dense geodetic measurements are available.

  7. Quantifying slip balance in the earthquake cycle: Coseismic slip model constrained by interseismic coupling

    KAUST Repository

    Wang, Lifeng

    2015-11-11

    The long-term slip on faults has to follow, on average, the plate motion, while slip deficit is accumulated over shorter time scales (e.g., between the large earthquakes). Accumulated slip deficits eventually have to be released by earthquakes and aseismic processes. In this study, we propose a new inversion approach for coseismic slip, taking interseismic slip deficit as prior information. We assume a linear correlation between coseismic slip and interseismic slip deficit, and invert for the coefficients that link the coseismic displacements to the required strain accumulation time and seismic release level of the earthquake. We apply our approach to the 2011 M9 Tohoku-Oki earthquake and the 2004 M6 Parkfield earthquake. Under the assumption that the largest slip almost fully releases the local strain (as indicated by borehole measurements, Lin et al., 2013), our results suggest that the strain accumulated along the Tohoku-Oki earthquake segment has been almost fully released during the 2011 M9 rupture. The remaining slip deficit can be attributed to the postseismic processes. Similar conclusions can be drawn for the 2004 M6 Parkfield earthquake. We also estimate the required time of strain accumulation for the 2004 M6 Parkfield earthquake to be ~25 years (confidence interval of [17, 43] years), consistent with the observed average recurrence time of ~22 years for M6 earthquakes in Parkfield. For the Tohoku-Oki earthquake, we estimate the recurrence time of~500-700 years. This new inversion approach for evaluating slip balance can be generally applied to any earthquake for which dense geodetic measurements are available.

  8. Seeding Social Capital? Urban Community Gardening and Social Capital

    DEFF Research Database (Denmark)

    Christensen, Søren

    2017-01-01

    There is a continuing debate regarding urban community gardening’s benefits to local communities, and a particularly interesting branch of this debate has focused on community gardens capacity to encourage and facilitate social interaction, which may generate social capital. Social capital...... is an increasingly important concept in international research and measures of social capital have been associated with various measures of health. In a meta-analysis of literature published between 2000 and 2016 regarding community gardens’ social advantages, through the lens of the concept of social capital......, it is demonstrated that several studies substantiate that urban community gardens create social capital, both bonding and bridging, and exhibit indications of linking. It is moreover identified how there is much to be learned from future research, illuminating how urban community gardens can foster social capital...

  9. Soil slips and debris flows on terraced slopes

    Science.gov (United States)

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

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

  10. Imbricated slip rate processes during slow slip transients imaged by low-frequency earthquakes

    Science.gov (United States)

    Lengliné, O.; Frank, W.; Marsan, D.; Ampuero, J. P.

    2017-12-01

    Low Frequency Earthquakes (LFEs) often occur in conjunction with transient strain episodes, or Slow Slip Events (SSEs), in subduction zones. Their focal mechanism and location consistent with shear failure on the plate interface argue for a model where LFEs are discrete dynamic ruptures in an otherwise slowly slipping interface. SSEs are mostly observed by surface geodetic instruments with limited resolution and it is likely that only the largest ones are detected. The time synchronization of LFEs and SSEs suggests that we could use the recorded LFEs to constrain the evolution of SSEs, and notably of the geodetically-undetected small ones. However, inferring slow slip rate from the temporal evolution of LFE activity is complicated by the strong temporal clustering of LFEs. Here we apply dedicated statistical tools to retrieve the temporal evolution of SSE slip rates from the time history of LFE occurrences in two subduction zones, Mexico and Cascadia, and in the deep portion of the San Andreas fault at Parkfield. We find temporal characteristics of LFEs that are similar across these three different regions. The longer term episodic slip transients present in these datasets show a slip rate decay with time after the passage of the SSE front possibly as t-1/4. They are composed of multiple short term transients with steeper slip rate decay as t-α with α between 1.4 and 2. We also find that the maximum slip rate of SSEs has a continuous distribution. Our results indicate that creeping faults host intermittent deformation at various scales resulting from the imbricated occurrence of numerous slow slip events of various amplitudes.

  11. Co-seismic slip, post-seismic slip, and largest aftershock associated with the 1994 Sanriku-haruka-oki, Japan, earthquake

    Science.gov (United States)

    Yagi, Yuji; Kikuchi, Masayuki; Nishimura, Takuya

    2003-11-01

    We analyzed continuous GPS data to investigate the spatio-temporal distribution of co-seismic slip, post-seismic slip, and largest aftershock associated with the 1994 Sanriku-haruka-oki, Japan, earthquake (Mw = 7.7). To get better resolution for co-seismic and post-seismic slip distribution, we imposed a weak constraint as a priori information of the co-seismic slip determined by seismic wave analyses. We found that the post-seismic slip during 100 days following the main-shock amount to as much moment release as the main-shock, and that the sites of co-seismic slip and post-seismic slip are partitioning on a plate boundary region in complimentary fashion. The major post-seismic slip was triggered by the mainshock in western side of the co-seismic slip, and the extent of the post-seismic slip is almost unchanged with time. It rapidly developed a shear stress concentration ahead of the slip area, and triggered the largest aftershock.

  12. Observing and modeling the spectrum of a slow slip event: Constraints on the scaling of slow slip and tremor

    Science.gov (United States)

    Hawthorne, J. C.; Bartlow, N. M.; Ghosh, A.

    2017-12-01

    We estimate the normalized moment rate spectrum of a slow slip event in Cascadia and then attempt to reproduce it. Our goal is to further assess whether a single physical mechanism could govern slow slip and tremor events, with durations that span 6 orders of magnitude, so we construct the spectrum by parameterizing a large slow slip event as the sum of a number of subevents with various durations. The spectrum estimate uses data from three sources: the GPS-based slip inversion of Bartlow et al (2011), PBO borehole strain measurements, and beamforming-based tremor moment estimates of Ghosh et al (2009). We find that at periods shorter than 1 day, the moment rate power spectrum decays as frequencyn, where n is between 0.7 and 1.4 when measured from strain and between 1.2 and 1.4 when inferred from tremor. The spectrum appears roughly flat at periods of 1 to 10 days, as both the 1-day-period strain and tremor data and the 6-day-period slip inversion data imply a moment rate power of 0.02 times the the total moment squared. We demonstrate one way to reproduce this spectrum: by constructing the large-scale slow slip event as the sum of a series of subevents. The shortest of these subevents could be interpreted as VLFEs or even LFEs, while longer subevents might represent the aseismic slip that drives rapid tremor reverals, streaks, or rapid tremor migrations. We pick the subevent magnitudes from a Gutenberg-Richter distribution and place the events randomly throughout a 30-day interval. Then we assign each subevent a duration that scales with its moment to a specified power. Finally, we create a moment rate function for each subevent and sum all of the moment rates. We compute the summed slow slip moment rate spectra with two approaches: a time-domain numerical computation and a frequency-domain analytical summation. Several sets of subevent parameters can allow the constructed slow slip event to match the observed spectrum. One allowable set of parameters is of

  13. Factors associated with use of slip-resistant shoes in US limited-service restaurant workers.

    Science.gov (United States)

    Verma, Santosh K; Courtney, Theodore K; Corns, Helen L; Huang, Yueng-Hsiang; Lombardi, David A; Chang, Wen-Ruey; Brennan, Melanye J; Perry, Melissa J

    2012-06-01

    Slips and falls are a leading cause of injury at work. Several studies have indicated that slip-resistant shoes can reduce the risk of occupational slips and falls. Few studies, however, have examined the determinants of slip-resistant shoe use. This study examined the individual and workplace factors associated with slip-resistant shoe use. 475 workers from 36 limited-service restaurants in the USA participated in a study of workplace slipping. Demographic and job characteristic information about each participant was collected. Restaurant managers provided information on whether slip-resistant shoes were provided and paid for by the employer and whether any guidance was given regarding slip-resistant shoe use when they were not provided. Kitchen floor coefficient of friction was measured. Slip-resistant status of the shoes was determined by noting the presence of a 'slip-resistant' marking on the sole. Poisson regression with robust SE was used to calculate prevalence ratios. 320 participants wore slip-resistant shoes (67%). In the multivariate analysis, the prevalence of slip-resistant shoe use was lowest in 15-19-year age group. Women were more likely to wear slip-resistant shoes (prevalence ratio 1.18, 95% CI 1.07 to 1.31). The prevalence of slip-resistant shoe use was lower when no guidance regarding slip-resistant shoes was given as compared to when they were provided by the employer (prevalence ratio 0.66, 95% CI 0.55 to 0.79). Education level, job tenure and the mean coefficient of friction had no significant effects on the use of slip-resistant shoes. Provision of slip-resistant shoes was the strongest predictor of their use. Given their effectiveness and low cost, employers should consider providing slip-resistant shoes at work.

  14. Debates sobre teoría del capital On some debates in capital theory

    Directory of Open Access Journals (Sweden)

    Sen Amartya

    1998-12-01

    Full Text Available En este articulo, Amartya Sen pone en escena una de las discusiones mas candentes en el debate económico de los años sesenta y setenta -la controversia de la teoría de capital entre las escuelas de Cambridge, la inglesa y la norteamericana- a traves de dos personajes: Euda y Subhuti, este ultimo un antiguo discípulo suyo que debido a algunos deslices debe reencarnar como economista en el siglo XX. La pieza esta llena de humor e ironía y, también, de agudas observaciones sobre este debate. Joan Robinson, (1954 abrio la discusión cuando pregunto como se media el capital en funcion de de producción agregada neoclásica. Sraffa (1960 mostro que la medida de capital no es independiente de la distribución y de los precios, y Garegnani (1970, que una funcion neoclasica bien comportada descansa en supuestos y restricciones demasiado exigentes e irreales. Sen , a traves de Buda, recomienda a su discípulo: "oh, Subhuti, no gastes tu vida en un problema que qiza sea trivial".In this article, Amartya Sen dramatizes one of the most heated discussions in the economic debates of the sixties and seventies the controversy over the theory of capital between the Cambridge schools of England and America- by means of two characters: Buddha and Subhuti, the latter an old disciple who, owing to some slips, must reincarnate as an economist in the twentieth century. The piece is full of humor and irony, as well as sharp observations about this debate. Joan Robinson (1954 opened the deba te when she asked how capital was measured in the neoclassical aggregated production function. Sraffa (1960 showed that the measurement of capital is not independent from the distribution of prices, and Garegnani (1970 showed that a well behaved neoclassical production function rests upon assumptions and restrictions that are too demanding and unreal. Sen, through Buddha, recommends to his disciple: "Do not spend your life, oh Subhuti, on a problem that may be trivial.

  15. Seismic slip on clay nano-foliation

    Science.gov (United States)

    Aretusini, S.; Pluemper, O.; Passelègue, F. X.; Spagnuolo, E.; Di Toro, G.

    2017-12-01

    Deformation processes active at seismic slip rates (ca. 1 m/s) on smectite-rich slipping zones are not well understood, although they likely control the mechanical behaviour of: i) subduction zone faults affected by tsunamigenic earthquakes (e.g. Japan Trench affected by Tohoku-Oki 2011 earthquake), ii) plate-boundary faults (e.g. San Andreas Fault), and iii) landslide decollements (e.g. 1963 Vajont landslide). Here we present a set of rotary experiments performed on water-dampened 2 mm thick clay-rich (70% wt. smectite and 30% wt. opal) gouge layers sheared at slip rates V ranging from 0.01 to 1.3 m/s, for 3 m of displacement under 5 MPa normal stress. Microstructural analyses were conducted on pre- and post-sheared gouges using focused ion beam scanning electron and transmission electron microscopy. All sheared gouges were slip weakening in the first 0.1 m of displacement, with friction coefficient decreasing from 0.3-0.45 to 0.5-0.15. Then, with progressive slip, gouges evolved to slip-strengthening (final friction coefficient of 0.35-0.48) at V ≤0.1 m/s and slip-neutral (final friction of 0.05) at V=1.3 m/s. Despite the large difference in the imposed slip rate and frictional behaviour, the slipping zone always consisted of a nano-foliation defined by sub-micrometric smectite crystals wrapping opal grains. The nano-foliated layer thickness decreased from 1.5 mm at V≤0.1 m/s to 0.15 mm at V=1.3 m/s. The presence of a similar nano-foliation in all the smectite-rich wet gouges suggests the activation of similar deformation processes, dominated by frictional slip on grain boundary and basal planes. The variation of deformed thickness with slip rate shows that dynamic weakening, occurring only at seismic slip rates, is controlled by strain localization.

  16. Simulation of engine auxiliary drive V-belt slip motion. Part 1. Development of belt slip model; Engine hoki V belt slip kyodo no simulation. 1. Belt slip model no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kurisu, T [Mazda Motor Corp., Hiroshima (Japan)

    1997-10-01

    V-belts are widely used for driving auxiliary components of an engine. Inadequet design of such belt system sometimes results in troubles such as belt squeak, side rubber separation and/or bottom rubber crack. However, there has been no design tools which can predict belt slip quantitatively. The author developed a motion simulation program of Auxiliary Drive V-Belt System considering belt slip. The program showed good prediction accuracy for belt slip motion. This paper describes the simulation model. 1 ref., 12 figs.

  17. Electro-optical hybrid slip ring

    Science.gov (United States)

    Hong, En

    2005-11-01

    The slip ring is a rotary electrical interface, collector, swivel or rotary joint. It is a physical system that can perform continuous data transfer and data exchange between a stationary and a rotating structure. A slip ring is generally used to transfer data or power from an unrestrained, continuously rotating electro-mechanical system in real-time, thereby simplifying operations and eliminating damage-prone wires dangling from moving joints. Slip rings are widely used for testing, evaluating, developing and improving various technical equipment and facilities with rotating parts. They are widely used in industry, especially in manufacturing industries employing turbo machinery, as in aviation, shipbuilding, aerospace, defense, and in precise facilities having rotating parts such as medical Computerized Tomography (CT) and MRI scanners and so forth. Therefore, any improvement in slip ring technology can impact large markets. Research and development in this field will have broad prospects long into the future. The goal in developing the current slip ring technology is to improve and increase the reliability, stability, anti-interference, and high data fidelity between rotating and stationary structures. Up to now, there have been numerous approaches used for signal and data transfer utilizing a slip ring such as metal contacts, wires, radio transmission, and even liquid media. However, all suffer from drawbacks such as data transfer speed limitations, reliability, stability, electro-magnetic interference and durability. The purpose of the current research is to break through these basic limitations using an optical solution, thereby improving performance in current slip ring applications. This dissertation introduces a novel Electro-Optical Hybrid Slip Ring technology, which makes "through the air" digital-optical communication between stationary and rotating systems a reality with high data transfer speed, better reliability and low interference susceptibility

  18. Active strike-slip faulting in El Salvador, Central America

    Science.gov (United States)

    Corti, Giacomo; Carminati, Eugenio; Mazzarini, Francesco; Oziel Garcia, Marvyn

    2005-12-01

    Several major earthquakes have affected El Salvador, Central America, during the Past 100 yr as a consequence of oblique subduction of the Cocos plate under the Caribbean plate, which is partitioned between trench-orthogonal compression and strike-slip deformation parallel to the volcanic arc. Focal mechanisms and the distribution of the most destructive earthquakes, together with geomorphologic evidence, suggest that this transcurrent component of motion may be accommodated by a major strike-slip fault (El Salvador fault zone). We present field geological, structural, and geomorphological data collected in central El Salvador that allow the constraint of the kinematics and the Quaternary activity of this major seismogenic strike-slip fault system. Data suggest that the El Salvador fault zone consists of at least two main ˜E-W fault segments (San Vicente and Berlin segments), with associated secondary synthetic (WNW-ESE) and antithetic (NNW-SSE) Riedel shears and NW-SE tensional structures. The two main fault segments overlap in a dextral en echelon style with the formation of an intervening pull-apart basin. Our original geological and geomorphologic data suggest a late Pleistocene Holocene slip rate of ˜11 mm/yr along the Berlin segment, in contrast with low historical seismicity. The kinematics and rates of deformation suggested by our new data are consistent with models involving slip partitioning during oblique subduction, and support the notion that a trench-parallel component of motion between the Caribbean and Cocos plates is concentrated along E-W dextral strike-slip faults parallel to the volcanic arc.

  19. SMEs capital structure determinants during severe economic crisis: The case of Greece

    Directory of Open Access Journals (Sweden)

    D. Balios

    2016-12-01

    Full Text Available The objective of this paper was to explore whether and how the main capital structure determinants of SMEs affected capital structure determination in different ways during the years of economic crisis. We used panel data of 8,052 SMEs operating in Greece during 2009–2012. We found that the effect of capital structure determinants on leverage does not change in an environment of economic crisis; larger SMEs continued to show higher debt ratios, the relationship between profitability and tangibility of assets with leverage continued to be negative, and growth was positively related to leverage.

  20. Quantitative numerical method for analysing slip traces observed by AFM

    International Nuclear Information System (INIS)

    Veselý, J; Cieslar, M; Coupeau, C; Bonneville, J

    2013-01-01

    Atomic force microscopy (AFM) is used more and more routinely to study, at the nanometre scale, the slip traces produced on the surface of deformed crystalline materials. Taking full advantage of the quantitative height data of the slip traces, which can be extracted from these observations, requires however an adequate and robust processing of the images. In this paper an original method is presented, which allows the fitting of AFM scan-lines with a specific parameterized step function without any averaging treatment of the original data. This yields a quantitative and full description of the changes in step shape along the slip trace. The strength of the proposed method is established on several typical examples met in plasticity by analysing nano-scale structures formed on the sample surface by emerging dislocations. (paper)

  1. Development of roller type side slip tester; Roller shiki side slip tester no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Nishiyama, S [Hiroshima City Industrial Technology Institute, Hiroshima (Japan); Harada, S; Harada, K

    1997-10-01

    This paper presents a new development of roller type side slip tester (RTSSI). The test equipment consists of four parts, which are developed in this research. These are a roller part, a control part, a remote control part and a CRT part. In this study, we especially investigated the mechanism and performance between tire and roller. We analyzed the amount of side slip with various toe angles. The developed tester is examined under the conditions that is considered in industrial applications. We investigated the influences of toe angle, size of tire, pressure of tire, coefficient of friction between tire and roller, pushing force of tire, revolution velocity of roller, axle load and so on. The validity of the developed RTSST is confirmed under these conditions. It was found that the RTSST can be used in practical use. Some measurement results are presented in the form of parametric plots. And we also compared measurements data between the RTSST and that of flat type using several automobiles. 4 refs., 8 figs., 4 tabs.

  2. Unravelling the Mysteries of Slip Histories, Validating Cosmogenic 36Cl Derived Slip Rates on Normal Faults

    Science.gov (United States)

    Goodall, H.; Gregory, L. C.; Wedmore, L.; Roberts, G.; Shanks, R. P.; McCaffrey, K. J. W.; Amey, R.; Hooper, A. J.

    2017-12-01

    The cosmogenic isotope chlorine-36 (36Cl) is increasingly used as a tool to investigate normal fault slip rates over the last 10-20 thousand years. These slip histories are being used to address complex questions, including investigating slip clustering and understanding local and large scale fault interaction. Measurements are time consuming and expensive, and as a result there has been little work done validating these 36Cl derived slip histories. This study aims to investigate if the results are repeatable and therefore reliable estimates of how normal faults have been moving in the past. Our approach is to test if slip histories derived from 36Cl are the same when measured at different points along the same fault. As normal fault planes are progressively exhumed from the surface they accumulate 36Cl. Modelling these 36Cl concentrations allows estimation of a slip history. In a previous study, samples were collected from four sites on the Magnola fault in the Italian Apennines. Remodelling of the 36Cl data using a Bayesian approach shows that the sites produced disparate slip histories, which we interpret as being due to variable site geomorphology. In this study, multiple sites have been sampled along the Campo Felice fault in the central Italian Apennines. Initial results show strong agreement between the sites we have processed so far and a previous study. This indicates that if sample sites are selected taking the geomorphology into account, then 36Cl derived slip histories will be highly similar when sampled at any point along the fault. Therefore our study suggests that 36Cl derived slip histories are a consistent record of fault activity in the past.

  3. Fixed recurrence and slip models better predict earthquake behavior than the time- and slip-predictable models 1: repeating earthquakes

    Science.gov (United States)

    Rubinstein, Justin L.; Ellsworth, William L.; Chen, Kate Huihsuan; Uchida, Naoki

    2012-01-01

    The behavior of individual events in repeating earthquake sequences in California, Taiwan and Japan is better predicted by a model with fixed inter-event time or fixed slip than it is by the time- and slip-predictable models for earthquake occurrence. Given that repeating earthquakes are highly regular in both inter-event time and seismic moment, the time- and slip-predictable models seem ideally suited to explain their behavior. Taken together with evidence from the companion manuscript that shows similar results for laboratory experiments we conclude that the short-term predictions of the time- and slip-predictable models should be rejected in favor of earthquake models that assume either fixed slip or fixed recurrence interval. This implies that the elastic rebound model underlying the time- and slip-predictable models offers no additional value in describing earthquake behavior in an event-to-event sense, but its value in a long-term sense cannot be determined. These models likely fail because they rely on assumptions that oversimplify the earthquake cycle. We note that the time and slip of these events is predicted quite well by fixed slip and fixed recurrence models, so in some sense they are time- and slip-predictable. While fixed recurrence and slip models better predict repeating earthquake behavior than the time- and slip-predictable models, we observe a correlation between slip and the preceding recurrence time for many repeating earthquake sequences in Parkfield, California. This correlation is not found in other regions, and the sequences with the correlative slip-predictable behavior are not distinguishable from nearby earthquake sequences that do not exhibit this behavior.

  4. Is the timing of surgery associated with avascular necrosis after unstable slipped capital femoral epiphysis? A multicenter study.

    Science.gov (United States)

    Kohno, Yusuke; Nakashima, Yasuharu; Kitano, Toshio; Irie, Taichi; Kita, Atsushi; Nakamura, Tomoyuki; Endo, Hirosuke; Fujii, Yosuke; Kuroda, Takayuki; Mitani, Shigeru; Kitoh, Hiroshi; Matsushita, Masaki; Hattori, Tadashi; Iwata, Koji; Iwamoto, Yukihide

    2017-01-01

    An unstable slipped capital femoral epiphysis (SCFE) is associated with a high rate of avascular necrosis (AVN). The etiology of AVN seems to be multifactorial, although it is not thoroughly known. The aims of our study were to determine the rate of AVN after an unstable SCFE and to investigate the risk factors for AVN, specifically evaluating the notion of an "unsafe window", during which medical interventions would increase the risk for AVN. This retrospective multicenter study included 60 patients with an unstable SCFE diagnosed between 1985 and 2014. Timing of surgery was evaluated for three time periods, from acute onset of symptoms to surgery: period I, 7 days. Multivariate logistic regression analysis was used to identify risk factors for AVN. Closed reduction and pinning was performed in 43 patients and in situ pinning in 17. Among these cases, 16 patients (27%) developed AVN. The rate of AVN was significantly higher in patients treated by closed reduction and pinning (15/43, 35%) than in those treated by in situ pinning (1/17, 5.9%) (p = 0.022). In patients treated by closed reduction and pinning, the incidence of AVN was 2/11 (18%) in period I, 10/13 (77%) in period II and 3/15 (20%) in period III, showing the significantly higher rate in period II (p = 0.002). The surgery provided in period II was identified as an independent risk factor for the development of AVN. Our rate of AVN was 27% using two classical treatment methods. Time-to-surgery, between 24 h and 7 days, was independently associated with AVN, supporting the possible existence of an "unsafe window" in patients with unstable SCFE treated by closed reduction and pinning. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

  5. Velocity- and slip-dependent weakening on the Tohoku plate boundary fault: shallow coseismic slip facilitated by foreshock afterslip

    Science.gov (United States)

    Ito, Y.; Ikari, M.; Ujiie, K.; Kopf, A.

    2016-12-01

    Understanding of role of slow earthquakes as they relate to the occurrence of both megathrust earthquakes and tsunami earthquakes is necessary to mitigate these disasters in the near future. Laboratory shearing experiments is one of important approach to evaluate these relationships. Here, we use powdered gouge samples from JFAST (IODP Expedition 343) Hole C0019E, core sample 17R-1, which is the plate boundary fault zone in the Japan Trench subduction zone. In this region, both large coseismic slip during the 2011 Tohoku-Oki earthquake as well as discrete slow slip events (SSE) have occurred. Experiments were conducted in a single-direct shear apparatus under normal stress of 16 MPa, with total shear displacements of up to 16 mm. We evaluate both the velocity- and slip-dependence of friction by extracting the velocity-dependent friction parameters a, b, and Dc, and measuring the rate of change in friction coefficient with shear displacement as the slip-dependence of friction. We report that in friction experiments using the Tohoku fault zone samples, an increase in sliding velocity exceeding that of earthquake afterslip can induce a change from steady-state frictional strength or slip hardening friction to slip-weakening frictional behavior. Our results show that the slip weakening is observed when the slip velocity exceeds 1 x 10-6 m/s during our experiments, while steady-state frictional strength or slip hardening is observed below 1x10-6 m/s. In the Japan Trench region, two slow events were observed at the downdip edge of the mainshock coseismic slip zone (< 30 m) were observed. These are an episodic SSE with a slip velocity of 0.1 x 10-6, and afterslip after the largest foreshock with a slip velocity of 2 x 10-6 m/s. This suggests that the afterslip may have facilitated the large coseismic slip during the mainshock on the plate boundary fault of the Tohoku-Oki earthquake.

  6. Spatiotemporal evolution of premonitory fault slip prior to stick-slip instability: New insight into the earthquake preparation

    Science.gov (United States)

    Zhuo, Y. Q.; Liu, P.; Guo, Y.; Ji, Y.; Ma, J.

    2017-12-01

    Premonitory fault slip, which begins with quasistatic propagation followed by quasidynamic propagation, may be a key clue bridging the "stick" state and "slip" state of a fault. More attentions have been paid for a long time to the temporal resolution of measurement than the spatial resolution, leading to the incomplete interpretation for the spatial evolution of premonitory slip, particularly during the quasistatic phase. In the present study, measurement of the quasistatic propagation of premonitory slip is achieved at an ultrahigh spatial resolution via a digital image correlation method. Multiple premonitory slip zones are observed and found to be controlled spatially by the fault contact heterogeneity, particularly the strong contact patches that prevent the propagation of premonitory slip and accumulate strain. As a result, premonitory slip is accelerated within constrained week contact spaces and consequently triggers the breakout of quasidynamic propagation. The results provide new insights into the quasistatic propagation of premonitory slip and may offer new interpretations for the earthquake nucleation process. This work is fund by the National Natural Science Foundation of China (Grant No. 41572181), the Basic Scientific Funding of Chinese National Nonprofit Institutes (Grant No. IGCEA1415, IGCEA1525), and the Early-Stage Work of Key Breakthrough Plan in Seismology from China Earthquake Administration.

  7. Stabilizing Stick-Slip Friction

    International Nuclear Information System (INIS)

    Capozza, Rosario; Barel, Itay; Urbakh, Michael; Rubinstein, Shmuel M.; Fineberg, Jay

    2011-01-01

    Even the most regular stick-slip frictional sliding is always stochastic, with irregularity in both the intervals between slip events and the sizes of the associated stress drops. Applying small-amplitude oscillations to the shear force, we show, experimentally and theoretically, that the stick-slip periods synchronize. We further show that this phase locking is related to the inhibition of slow rupture modes which forces a transition to fast rupture, providing a possible mechanism for observed remote triggering of earthquakes. Such manipulation of collective modes may be generally relevant to extended nonlinear systems driven near to criticality.

  8. Limits of recovery against slip-induced falls while walking.

    Science.gov (United States)

    Yang, Feng; Bhatt, Tanvi; Pai, Yi-Chung

    2011-10-13

    Slip-induced falls in gait often have devastating consequences. The purposes of this study were 1) to select the determinants that can best discriminate the outcomes (recoveries or falls) of an unannounced slip induced in gait (and to find their corresponding threshold, i.e., the limits of recovery, which can clearly separate these two outcomes), and 2) to verify these results in a subset of repeated-slip trials. Based on the data collected from 69 young subjects during a slip induced in gait, nine different ways of combining the center of mass (COM) stability, the hip height, and its vertical velocity were investigated with the aid of logistic regression. The results revealed that the COM stability (s) and limb support (represented by the quotient of hip vertical velocity to hip height, S(hip)) recorded at the instant immediately prior to the recovery step touchdown were sufficiently sensitive to account for all (100%) variance in falls, and specific enough to account for nearly all (98.3%) variability in recoveries. This boundary (S(hip)=-0.22s-0.25), which quantifies the risk of falls in the stability-limb support quotient (s-S(hip)) domain, was fully verified using second-slip and third-slip trials (n=76) with classification of falls at 100% and recoveries at 98.6%. The severity of an actual fall is likely to be greater further below the boundary, while the likelihood of a fall diminishes above it. Finally, the slope of the boundary also indicates the tradeoff between the stability and limb support, whereby high stability can compensate for the insufficiency in limb support, or vice versa. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Slip rate and tremor genesis in Cascadia

    Science.gov (United States)

    Wech, Aaron G.; Bartlow, Noel M.

    2014-01-01

    At many plate boundaries, conditions in the transition zone between seismogenic and stable slip produce slow earthquakes. In the Cascadia subduction zone, these events are consistently observed as slow, aseismic slip on the plate interface accompanied by persistent tectonic tremor. However, not all slow slip at other plate boundaries coincides spatially and temporally with tremor, leaving the physics of tremor genesis poorly understood. Here we analyze seismic, geodetic, and strainmeter data in Cascadia to observe for the first time a large, tremor-generating slow earthquake change from tremor-genic to silent and back again. The tremor falls silent at reduced slip speeds when the migrating slip front pauses as it loads the stronger adjacent fault segment to failure. The finding suggests that rheology and slip-speed-regulated stressing rate control tremor genesis, and the same section of fault can slip both with and without detectable tremor, limiting tremor's use as a proxy for slip.

  10. Analytical approximations for stick-slip vibration amplitudes

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel; Fidlin, A.

    2003-01-01

    , the amplitudes, and the base frequencies of friction-induced stick¿slip and pure-slip oscillations. For stick¿slip oscillations, this is accomplished by using perturbation analysis for the finite time interval of the stick phase, which is linked to the subsequent slip phase through conditions of continuity...

  11. The prevention of slipping accidents: a review and discussion of work related to the methodology of measuring slip resistance

    OpenAIRE

    Leclercq , Sylvie

    1999-01-01

    International audience; The recommendations made after the analysis of accidents following an incident of slipping often include the use of anti-slip footwear and/or the installation of an anti-slip floor covering. Such recommendations make it necessary to study biomechanical and tribologic phenomena that occur during slipping, in particular in order to develop criteria for the evaluation of the slip resistance of footwear and floor surfaces. Consequently, research which deals with the preven...

  12. Does Venture Capital Spur Innovation?

    OpenAIRE

    Samuel Kortum; Josh Lerner

    1998-01-01

    While policymakers often assume venture capital has a profound impact on innovation, that premise has not been evaluated systematically. We address this omission by examining the influence of venture capital on patented inventions in the United States across twenty industries over three decades. We address concerns about causality in several ways, including exploiting a 1979 policy shift that spurred venture capital fundraising. We find that the amount of venture capital activity in an indust...

  13. Modeling and Analyzing the Slipping of the Ball Screw

    Directory of Open Access Journals (Sweden)

    Nannan Xu

    Full Text Available AbstractThis paper aims to set up the ball systematic slipping model and analyze the slipping characteristics caused by different factors for a ball screw operating at high speeds. To investigate the ball screw slipping mechanism, transformed coordinate system should be established firstly. Then it is used to set up mathematical modeling for the ball slipping caused by the three main reasons and the speed of slipping can be calculated. Later, the influence of the contact angle, helix angle and screw diameter for ball screw slipping will be analyzed according to the ball slipping model and slipping speeds equation and the slipping analysis will be obtained. Finally, curve of slipping analysis and that of mechanical efficiency of the ball screw analysis by Lin are compared, which will indirectly verify the correctness of the slipping model. The slipping model and the curve of slipping analysis established in this paper will provide theory basis for reducing slipping and improving the mechanical efficiency of a ball screw operating at high speeds.

  14. Capitalism: A System of Conspiracy

    OpenAIRE

    Das, Subhendu

    2010-01-01

    There are some myths about American capitalism. Some of them are (1) Capitalism made America the richest nation, (2) Capitalism is based on self interest, and (3) America has democracy. We show that the survival of capitalism is based on several powerful conspiracy theories. We briefly describe these conspiracies. Our analysis is based on the following principles: (a) Laws of conservation, (b) System theoretic concepts, and (c) The global space time (GST) environment. Using these princip...

  15. Velocities of dislocation groups in very thin neutron-irradiated copper single crystals measured by slip line cinematography

    Energy Technology Data Exchange (ETDEWEB)

    Potthoff, H.H. (Technische Univ. Braunschweig (Germany, F.R.). Inst. fuer Metallphysik und Nukleare Festkoerperphysik)

    1983-05-16

    Slip line development on very thin flat single crystals of neutron-irradiated Cu (thickness down to only 15 to 20 ..mu..m, orientation for single glide, yield region, room temperature) is recorded by high-speed cinematography during tensile deformation. In such very thin crystals glide dislocations on the slip plane must be arranged in a rather simple way. Drops in tensile load occuring during initiation of single slip lines at the Lueders band front indicate that in the beginning of a slip line development dislocation groups traverse the whole glide plane in very short times. Evaluating the data measured for the slip line growth v/sub s/ >= 10 cm/s is found for screw dislocations and v/sub e/ >= v/sub s/ for edge dislocations. For later stages on thin crystals and for all stages on thick crystals (>= several 100 ..mu..m) slip line development is much slower and slip line show many cross slip events which then appear to control the mean velocity of the dislocations.

  16. Slip of Spreading Viscoplastic Droplets.

    Science.gov (United States)

    Jalaal, Maziyar; Balmforth, Neil J; Stoeber, Boris

    2015-11-10

    The spreading of axisymmetric viscoplastic droplets extruded slowly on glass surfaces is studied experimentally using shadowgraphy and swept-field confocal microscopy. The microscopy furnishes vertical profiles of the radial velocity using particle image velocimetry (PIV) with neutrally buoyant tracers seeded in the fluid. Experiments were conducted for two complex fluids: aqueous solutions of Carbopol and xanthan gum. On untreated glass surfaces, PIV demonstrates that both fluids experience a significant amount of effective slip. The experiments were repeated on glass that had been treated to feature positive surface charges, thereby promoting adhesion between the negatively charged polymeric constituents of the fluids and the glass surface. The Carbopol and xanthan gum droplets spread more slowly on the treated surface and to a smaller radial distance. PIV demonstrated that this reduced spreading was associated with a substantial reduction in slip. For Carbopol, the effective slip could be eliminated entirely to within the precision of the PIV measurements; the reduction in slip was less effective for xanthan gum, with a weak slip velocity remaining noticeable.

  17. SLIP CASTING METHOD

    Science.gov (United States)

    Allison, A.G.

    1959-09-01

    S>A process is described for preparing a magnesium oxide slip casting slurry which when used in conjunction with standard casting techniques results in a very strong "green" slip casting and a fired piece of very close dimensional tolerance. The process involves aging an aqueous magnestum oxide slurry, having a basic pH value, until it attains a specified critical viscosity at which time a deflocculating agent is added without upsetting the basic pH value.

  18. A Model for Low-Frequency Earthquake Slip

    Science.gov (United States)

    Chestler, S. R.; Creager, K. C.

    2017-12-01

    Using high-resolution relative low-frequency earthquake (LFE) locations, we calculate the patch areas (Ap) of LFE families. During episodic tremor and slip (ETS) events, we define AT as the area that slips during LFEs and ST as the total amount of summed LFE slip. Using observed and calculated values for AP, AT, and ST, we evaluate two end-member models for LFE slip within an LFE family patch. In the ductile matrix model, LFEs produce 100% of the observed ETS slip (SETS) in distinct subpatches (i.e., AT ≪ AP). In the connected patch model, AT = AP, but ST ≪ SETS. LFEs cluster into 45 LFE families. Spatial gaps (˜10 to 20 km) between LFE family clusters and smaller gaps within LFE family clusters serve as evidence that LFE slip is heterogeneous on multiple spatial scales. We find that LFE slip only accounts for ˜0.2% of the slip within the slow slip zone. There are depth-dependent trends in the characteristic (mean) moment and in the number of LFEs during both ETS events (only) and the entire ETS cycle (Mcets and NTets and Mcall and NTall, respectively). During ETS, Mc decreases with downdip distance but NT does not change. Over the entire ETS cycle, Mc decreases with downdip distance, but NT increases. These observations indicate that deeper LFE slip occurs through a larger number (800-1,200) of small LFEs, while updip LFE slip occurs primarily during ETS events through a smaller number (200-600) of larger LFEs. This could indicate that the plate interface is stronger and has a higher stress threshold updip.

  19. Back analysis of fault-slip in burst prone environment

    Science.gov (United States)

    Sainoki, Atsushi; Mitri, Hani S.

    2016-11-01

    In deep underground mines, stress re-distribution induced by mining activities could cause fault-slip. Seismic waves arising from fault-slip occasionally induce rock ejection when hitting the boundary of mine openings, and as a result, severe damage could be inflicted. In general, it is difficult to estimate fault-slip-induced ground motion in the vicinity of mine openings because of the complexity of the dynamic response of faults and the presence of geological structures. In this paper, a case study is conducted for a Canadian underground mine, herein called "Mine-A", which is known for its seismic activities. Using a microseismic database collected from the mine, a back analysis of fault-slip is carried out with mine-wide 3-dimensional numerical modeling. A back analysis is conducted to estimate the physical and mechanical properties of the causative fracture or shear zones. One large seismic event has been selected for the back analysis to detect a fault-slip related seismic event. In the back analysis, the shear zone properties are estimated with respect to moment magnitude of the seismic event and peak particle velocity (PPV) recorded by a strong ground motion sensor. The estimated properties are then validated through comparison with peak ground acceleration recorded by accelerometers. Lastly, ground motion in active mining areas is estimated by conducting dynamic analysis with the estimated values. The present study implies that it would be possible to estimate the magnitude of seismic events that might occur in the near future by applying the estimated properties to the numerical model. Although the case study is conducted for a specific mine, the developed methodology can be equally applied to other mines suffering from fault-slip related seismic events.

  20. Direct measurement of wall slip and slip layer thickness of non-Brownian hard-sphere suspensions in rectangular channel flows

    Science.gov (United States)

    Jesinghausen, Steffen; Weiffen, Rene; Schmid, Hans-Joachim

    2016-09-01

    Wall slip is a long-known phenomenon in the field of rheology. Nevertheless, the origin and the evolution are not completely clear yet. Regarding suspensions, the effect becomes even more complicated, because different mechanisms like pure slip or slip due to particle migration have to be taken into account. Furthermore, suspensions themselves show many flow anomalies and the isolation of slip is complicated. In order to develop working physical models, further insight is necessary. In this work, we measured experimentally the wall slip velocities of different highly filled suspensions in a rectangular slit die directly with respect to the particle concentration and the particle size. The slip velocities were obtained using a particle image velocimetry (PIV) system. The suspensions consisting of a castor oil-cinnamon oil blend and PMMA particles were matched in terms of refractive indexes to appear transparent. Hereby, possible optical path lengths larger than 15 mm were achieved. The slip velocities were found to be in a quadratic relation to the wall shear stress. Furthermore, the overall flow rate as well as the particle concentration has a direct influence on the slip. Concerning the shear stress, there seem to be two regions of slip with different physical characteristics. Furthermore, we estimated the slip layer thickness directly from the velocity profiles and propose a new interpretation. The PIV technique is used to investigate the viscosity and implicit the concentration profile in the slit die. It is shown that the particle migration process is quite fast.

  1. Slip-dependent weakening on shallow plate boundary fault in the Japan subduction zone: shallow coseismic slip facilitated by foreshock afterslip

    Science.gov (United States)

    Ito, Yoshi; Ikari, Matt; Ujiie, Kohtaro; Kopf, Achim

    2017-04-01

    Understanding of role of slow earthquakes as they relate to the occurrence of both megathrust earthquakes and tsunami earthquakes is necessary to mitigate these disasters in the near future. Laboratory shearing experiments is one of important approach to evaluate these relationships. Here, we use powdered gouge samples from JFAST (IODP Expedition 343) Hole C0019E, core sample 17R-1, which is the plate boundary fault zone in the Japan Trench subduction zone. In this region, both large coseismic slip during the 2011 Tohoku-Oki earthquake as well as discrete slow slip events (SSE) have occurred. Experiments were conducted in a single-direct shear apparatus under normal stress of 16 MPa, with total shear displacements of up to 16 mm. We evaluate the slip-dependence of friction by extracting the velocity-dependent friction parameters a, b, and Dc , and also measure the rate of change in friction coefficient with shear displacement as the slip-dependence of friction. We report that in friction experiments using the Tohoku fault zone samples, an increase in sliding velocity exceeding that of earthquake afterslip can induce a change from steady-state frictional strength or slip hardening friction to slip-weakening frictional behavior. Our results show that the slip weakening is observed when the slip velocity exceeds 3.7 × 10-6 m/s during our experiments, while steady-state frictional strength or slip hardening is observed below 1 × 10-6 m/s. In the Japan Trench region, two slow events prior to the mainshock were observed in the mainshock area with a coseismic slip exceeding 30 m . One event is an episodic SSE with a slip velocity of 0.1 × 10-6 , and the other is afterslip after the largest Tohoku earthquake foreshock with a slip velocity exceeding 2 × 10-6 m/s. Our experiments show that slip-weakening friction should be expected at the afterslip rate, suggesting that the afterslip may have facilitated the large coseismic slip during the mainshock on the plate boundary

  2. Stick–slip behaviour on Au(111 with adsorption of copper and sulfate

    Directory of Open Access Journals (Sweden)

    Nikolay Podgaynyy

    2015-03-01

    Full Text Available Several transitions in the friction coefficient with increasing load are found on Au(111 in sulfuric acid electrolyte containing Cu ions when a monolayer (or submonolayer of Cu is adsorbed. At the corresponding normal loads, a transition to double or multiple slips in stick–slip friction is observed. The stick length in this case corresponds to multiples of the lattice distance of the adsorbed sulfate, which is adsorbed in a √3 × √7 superstructure on the copper monolayer. Stick–slip behaviour for the copper monolayer as well as for 2/3 coverage can be observed at FN ≥ 15 nN. At this normal load, a change from a small to a large friction coefficient occurs. This leads to the interpretation that the tip penetrates the electrochemical double layer at this point. At the potential (or point of zero charge (pzc, stick–slip resolution persists at all normal forces investigated.

  3. PROCESSING OF CONCENTRATED AQUEOUS ZIRCONIA-BIOGLASS SLIPS BY SLIP CASTING

    Directory of Open Access Journals (Sweden)

    Beltina Leon

    2017-03-01

    Full Text Available 3 mol% yttria-partially stabilized zirconia (Y-TZP powder and a sol-gel derived CaO- P₂O₅- SiO₂ (64S bioglass, were used to produce Y-TZP- bioglass slip cast compacts. The rheological properties of concentrated aqueous Y-TZP- 64S suspensions prepared with two different glass contents: 10.5 vol% and 19.9 vol%, and ammonium polyacrylate (NH₄PA as dispersant, were investigated and compared with those of Y-TZP. The density of green cast samples was related to the degree of slip dispersion. The substitution of Y-TZP by 64S glass in the mixtures resulted in greater adsorption of NH₄PA; however, the viscosity and yield stress values of Y-TZP-64S slips were higher than those of Y-TZP ones for the solid loadings studied. The increase in the glass content from 10.5 to 19.9 vol% increased the viscosity and yield stress values. The presence of 64S glass in the mixtures resulted in a less dense packing of cast samples.

  4. Inorganic glass ceramic slip rings

    Science.gov (United States)

    Glossbrenner, E. W.; Cole, S. R.

    1972-01-01

    Prototypes of slip rings have been fabricated from ceramic glass, a material which is highly resistant to deterioration due to high temperature. Slip ring assemblies were not structurally damaged by mechanical tests and performed statisfactorily for 200 hours.

  5. Resolving the Detailed Spatiotemporal Slip Evolution of Deep Tremor in Western Japan

    Science.gov (United States)

    Ohta, Kazuaki; Ide, Satoshi

    2017-12-01

    We study the detailed spatiotemporal behavior of deep tremor in western Japan through the development and application of a new slip inversion method. Although many studies now recognize tremor as shear slip along the plate interface manifested in low-frequency earthquake (LFE) swarms, a conventional slip inversion analysis is not available for tremor due to insufficient knowledge of source locations and Green's functions. Here we introduce synthetic template waveforms, which are typical tremor waveforms obtained by stacking LFE seismograms at arranged points along the plate interface. Using these synthetic template waveforms as substitutes for Green's functions, we invert the continuous tremor waveforms using an iterative deconvolution approach with Bayesian constraints. We apply this method to two tremor burst episodes in western and central Shikoku, Japan. The estimated slip distribution from a 12 day tremor burst episode in western Shikoku is heterogeneous, with several patchy areas of slip along the plate interface where rapid moment releases with durations of tremor burst episode that occurred coincidentally with a very low frequency earthquake (VLF), we observe that the source size of the VLF is much larger than that estimated from tremor activity in western Shikoku. These differences in the size of the slip region may dictate the visibility of VLF signals in observed seismograms, which has implications for the mechanics of slow earthquakes and subduction zone processes.

  6. Nonlinear dynamical triggering of slow slip

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Paul A [Los Alamos National Laboratory; Knuth, Matthew W [WISCONSIN; Kaproth, Bryan M [PENN STATE; Carpenter, Brett [PENN STATE; Guyer, Robert A [Los Alamos National Laboratory; Le Bas, Pierre - Yves [Los Alamos National Laboratory; Daub, Eric G [Los Alamos National Laboratory; Marone, Chris [PENN STATE

    2010-12-10

    Among the most fascinating, recent discoveries in seismology have been the phenomena of triggered slip, including triggered earthquakes and triggered-tremor, as well as triggered slow, silent-slip during which no seismic energy is radiated. Because fault nucleation depths cannot be probed directly, the physical regimes in which these phenomena occur are poorly understood. Thus determining physical properties that control diverse types of triggered fault sliding and what frictional constitutive laws govern triggered faulting variability is challenging. We are characterizing the physical controls of triggered faulting with the goal of developing constitutive relations by conducting laboratory and numerical modeling experiments in sheared granular media at varying load conditions. In order to simulate granular fault zone gouge in the laboratory, glass beads are sheared in a double-direct configuration under constant normal stress, while subject to transient perturbation by acoustic waves. We find that triggered, slow, silent-slip occurs at very small confining loads ({approx}1-3 MPa) that are smaller than those where dynamic earthquake triggering takes place (4-7 MPa), and that triggered slow-slip is associated with bursts of LFE-like acoustic emission. Experimental evidence suggests that the nonlinear dynamical response of the gouge material induced by dynamic waves may be responsible for the triggered slip behavior: the slip-duration, stress-drop and along-strike slip displacement are proportional to the triggering wave amplitude. Further, we observe a shear-modulus decrease corresponding to dynamic-wave triggering relative to the shear modulus of stick-slips. Modulus decrease in response to dynamical wave amplitudes of roughly a microstrain and above is a hallmark of elastic nonlinear behavior. We believe that the dynamical waves increase the material non-affine elastic deformation during shearing, simultaneously leading to instability and slow-slip. The inferred

  7. Velocities of dislocation groups in very thin neutron-irradiated copper single crystals measured by slip line cinematography

    International Nuclear Information System (INIS)

    Potthoff, H.H.

    1983-01-01

    Slip line development on very thin flat single crystals of neutron-irradiated Cu (thickness down to only 15 to 20 μm, orientation for single glide, yield region, room temperature) is recorded by high-speed cinematography during tensile deformation. In such very thin crystals glide dislocations on the slip plane must be arranged in a rather simple way. Drops in tensile load occuring during initiation of single slip lines at the Lueders band front indicate that in the beginning of a slip line development dislocation groups traverse the whole glide plane in very short times. Evaluating the data measured for the slip line growth v/sub s/ >= 10 cm/s is found for screw dislocations and v/sub e/ >= v/sub s/ for edge dislocations. For later stages on thin crystals and for all stages on thick crystals (>= several 100 μm) slip line development is much slower and slip line show many cross slip events which then appear to control the mean velocity of the dislocations. (author)

  8. Localization in the brittle field: the role of frictional properties and implications for earthquake slip

    Science.gov (United States)

    Tullis, T.

    2003-04-01

    Rotary shear friction experiments on layers of simulated gouge and on bare surfaces of rock that generate gouge, with displacements up to several meters, show that in some situations slip becomes localized. The two constitutive parameters that control whether slip localizes are the displacement and the velocity dependence of the shear strength. When slip-weakening and velocity-weakening both occur, slip localizes, since the overall resistance is reduced and less energy is dissipated. Similarly, when slip- and velocity-strengthening both occur, slip delocalizes, again because less energy is dissipated. If the variation of shear resistance with slip and velocity are of opposite sign, then the magnitude of the slip and rate dependencies and the amount and rate of slip determine whether localization or delocalization occur. In most laboratory experiments, the displacement dependence of the strength is minimal and the velocity dependence controls the tendency for localization. However, some experiments illustrate the situation in which the displacement dependence dominates. Regardless of their underlying causes, slip- and velocity-weakening result in unstable slip in compliant systems. Consequently unstable slip and localization are linked through these constitutive properties. This connection between unstable slip, displacement/velocity-weakening, and localization suggests that slip on faults that occurs primarily via earthquakes will be localized. However, localization is more complicated on natural faults because laboratory faults are geometrically simpler than natural ones. Laboratory faults are smooth at long wavelengths, whereas natural faults have approximately a self-similar surface roughness, the amplitude of irregularities being proportional to their wavelength. Thus, slip on a localized surface in a laboratory fault can continue indefinitely, whereas slip on natural faults is likely to require fracture of new wall rock as sufficient slip brings higher

  9. Aftershock distribution as a constraint on the geodetic model of coseismic slip for the 2004 Parkfield earthquake

    Science.gov (United States)

    Bennington, Ninfa; Thurber, Clifford; Feigl, Kurt; ,

    2011-01-01

    Several studies of the 2004 Parkfield earthquake have linked the spatial distribution of the event’s aftershocks to the mainshock slip distribution on the fault. Using geodetic data, we find a model of coseismic slip for the 2004 Parkfield earthquake with the constraint that the edges of coseismic slip patches align with aftershocks. The constraint is applied by encouraging the curvature of coseismic slip in each model cell to be equal to the negative of the curvature of seismicity density. The large patch of peak slip about 15 km northwest of the 2004 hypocenter found in the curvature-constrained model is in good agreement in location and amplitude with previous geodetic studies and the majority of strong motion studies. The curvature-constrained solution shows slip primarily between aftershock “streaks” with the continuation of moderate levels of slip to the southeast. These observations are in good agreement with strong motion studies, but inconsistent with the majority of published geodetic slip models. Southeast of the 2004 hypocenter, a patch of peak slip observed in strong motion studies is absent from our curvature-constrained model, but the available GPS data do not resolve slip in this region. We conclude that the geodetic slip model constrained by the aftershock distribution fits the geodetic data quite well and that inconsistencies between models derived from seismic and geodetic data can be attributed largely to resolution issues.

  10. The role of water in slip casting

    Science.gov (United States)

    Mccauley, R. A.; Phelps, G. W.

    1984-01-01

    Slips and casting are considered in terms of physical and colloidal chemistry. Casting slips are polydisperse suspensions of lyophobic particles in water, whose degree of coagulation is controlled by interaction of flocculating and deflocculating agents. Slip casting rate and viscosity are functions of temperature. Slip rheology and response to deflocculating agents varies significantly as the kinds and amounts of colloid modifiers change. Water is considered as a raw material. Various concepts of water/clay interactions and structures are discussed. Casting is a de-watering operation in which water moves from slip to cast to mold in response to a potential energy termed moisture stress. Drying is an evaporative process from a free water surface.

  11. Triggered surface slips in the Salton Trough associated with the 1999 Hector Mine, California, earthquake

    Science.gov (United States)

    Rymer, M.J.; Boatwright, J.; Seekins, L.C.; Yule, J.D.; Liu, J.

    2002-01-01

    Surface fracturing occurred along the southern San Andreas, Superstition Hills, and Imperial faults in association with the 16 October 1999 (Mw 7.1) Hector Mine earthquake, making this at least the eighth time in the past 31 years that a regional earthquake has triggered slip along faults in the Salton Trough. Fractures associated with the event formed discontinuous breaks over a 39-km-long stretch of the San Andreas fault, from the Mecca Hills southeastward to Salt Creek and Durmid Hill, a distance from the epicenter of 107 to 139 km. Sense of slip was right lateral; only locally was there a minor (~1 mm) vertical component of slip. Dextral slip ranged from 1 to 13 mm. Maximum slip values in 1999 and earlier triggered slips are most common in the central Mecca Hills. Field evidence indicates a transient opening as the Hector Mine seismic waves passed the southern San Andreas fault. Comparison of nearby strong-motion records indicates several periods of relative opening with passage of the Hector Mine seismic wave-a similar process may have contributed to the field evidence of a transient opening. Slip on the Superstition Hills fault extended at least 9 km, at a distance from the Hector Mine epicenter of about 188 to 196 km. This length of slip is a minimum value, because we saw fresh surface breakage extending farther northwest than our measurement sites. Sense of slip was right lateral; locally there was a minor (~1 mm) vertical component of slip. Dextral slip ranged from 1 to 18 mm, with the largest amounts found distributed (or skewed) away from the Hector Mine earthquake source. Slip triggered on the Superstition Hills fault commonly is skewed away from the earthquake source, most notably in 1968, 1979, and 1999. Surface slip on the Imperial fault and within the Imperial Valley extended about 22 km, representing a distance from the Hector Mine epicenter of about 204 to 226 km. Sense of slip dominantly was right lateral; the right-lateral component of slip

  12. Evidence for Truncated Exponential Probability Distribution of Earthquake Slip

    KAUST Repository

    Thingbaijam, Kiran Kumar; Mai, Paul Martin

    2016-01-01

    Earthquake ruptures comprise spatially varying slip on the fault surface, where slip represents the displacement discontinuity between the two sides of the rupture plane. In this study, we analyze the probability distribution of coseismic slip, which provides important information to better understand earthquake source physics. Although the probability distribution of slip is crucial for generating realistic rupture scenarios for simulation-based seismic and tsunami-hazard analysis, the statistical properties of earthquake slip have received limited attention so far. Here, we use the online database of earthquake source models (SRCMOD) to show that the probability distribution of slip follows the truncated exponential law. This law agrees with rupture-specific physical constraints limiting the maximum possible slip on the fault, similar to physical constraints on maximum earthquake magnitudes.We show the parameters of the best-fitting truncated exponential distribution scale with average coseismic slip. This scaling property reflects the control of the underlying stress distribution and fault strength on the rupture dimensions, which determines the average slip. Thus, the scale-dependent behavior of slip heterogeneity is captured by the probability distribution of slip. We conclude that the truncated exponential law accurately quantifies coseismic slip distribution and therefore allows for more realistic modeling of rupture scenarios. © 2016, Seismological Society of America. All rights reserverd.

  13. Evidence for Truncated Exponential Probability Distribution of Earthquake Slip

    KAUST Repository

    Thingbaijam, Kiran K. S.

    2016-07-13

    Earthquake ruptures comprise spatially varying slip on the fault surface, where slip represents the displacement discontinuity between the two sides of the rupture plane. In this study, we analyze the probability distribution of coseismic slip, which provides important information to better understand earthquake source physics. Although the probability distribution of slip is crucial for generating realistic rupture scenarios for simulation-based seismic and tsunami-hazard analysis, the statistical properties of earthquake slip have received limited attention so far. Here, we use the online database of earthquake source models (SRCMOD) to show that the probability distribution of slip follows the truncated exponential law. This law agrees with rupture-specific physical constraints limiting the maximum possible slip on the fault, similar to physical constraints on maximum earthquake magnitudes.We show the parameters of the best-fitting truncated exponential distribution scale with average coseismic slip. This scaling property reflects the control of the underlying stress distribution and fault strength on the rupture dimensions, which determines the average slip. Thus, the scale-dependent behavior of slip heterogeneity is captured by the probability distribution of slip. We conclude that the truncated exponential law accurately quantifies coseismic slip distribution and therefore allows for more realistic modeling of rupture scenarios. © 2016, Seismological Society of America. All rights reserverd.

  14. EMG and Kinematic Responses to Unexpected Slips After Slip Training in Virtual Reality

    Science.gov (United States)

    Parijat, Prakriti; Lockhart, Thurmon E.

    2015-01-01

    The objective of the study was to design a virtual reality (VR) training to induce perturbation in older adults similar to a slip and examine the effect of the training on kinematic and muscular responses in older adults. Twenty-four older adults were involved in a laboratory study and randomly assigned to two groups (virtual reality training and control). Both groups went through three sessions including baseline slip, training, and transfer of training on slippery surface. The training group experienced twelve simulated slips using a visual perturbation induced by tilting a virtual reality scene while walking on the treadmill and the control group completed normal walking during the training session. Kinematic, kinetic, and EMG data were collected during all the sessions. Results demonstrated the proactive adjustments such as increased trunk flexion at heel contact after training. Reactive adjustments included reduced time to peak activations of knee flexors, reduced knee coactivation, reduced time to trunk flexion, and reduced trunk angular velocity after training. In conclusion, the study findings indicate that the VR training was able to generate a perturbation in older adults that evoked recovery reactions and such motor skill can be transferred to the actual slip trials. PMID:25296401

  15. A Model for Low-Frequency Earthquake Slip in Cascadia

    Science.gov (United States)

    Chestler, S.; Creager, K.

    2017-12-01

    Low-Frequency Earthquakes (LFEs) are commonly used to identify when and where slow slip occurred, especially for slow slip events that are too small to be observed geodetically. Yet, an understanding of how slip occurs within an LFE family patch, or patch on the plate interface where LFEs repeat, is limited. How much slip occurs per LFE and over what area? Do all LFEs within an LFE family rupture the exact same spot? To answer these questions, we implement a catalog of 39,966 LFEs, sorted into 45 LFE families, beneath the Olympic Peninsula, WA. LFEs were detected and located using data from approximately 100 3-component stations from the Array of Arrays experiment. We compare the LFE family patch area to the area within the LFE family patch that slips through LFEs during Cascadia Episodic Tremor and Slip (ETS) events. Patch area is calculated from relative LFE locations, solved for using the double difference method. Slip area is calculated from the characteristic moment (mean of the exponential moment-frequency distribution) and number LFEs for each family and geodetically measured ETS slip. We find that 0.5-5% of the area within an LFE family patch slips through LFEs. The rest must deform in some other manner (e.g., ductile deformation). We also explore LFE slip patterns throughout the entire slow slip zone. Is LFE slip uniform? Does LFE slip account for all geodetically observed slow slip? Double difference relocations reveal that LFE families are 2 km patches where LFE are clustered close together. Additionally, there are clusters of LFE families with diameters of 4-15 km. There are gaps with no observable, repeating LFEs between LFE families in clusters and between clusters of LFE families. Based on this observation, we present a model where LFE slip is heterogeneous on multiple spatial scales. Clusters of LFE families may represent patches with higher strength than the surrounding areas. Finally, we find that LFE slip only accounts for a small fraction ( 0

  16. Pedestrians in wintertime-effects of using anti-slip devices.

    Science.gov (United States)

    Berggård, Glenn; Johansson, Charlotta

    2010-07-01

    Pedestrians slipping and falling is a major safety problem around the world, not least in countries with long winters such as Sweden. About 25000-30000 people need medical care every year for treatment of fall injuries in Sweden. Use of appropriate shoes and anti-slip devices are examples of individual measures that have been suggested to prevent slipping and falling. An intervention study was performed during the period February to April 2008. The study, which focused on healthy adults in northern Sweden, examined the effect of using anti-slip devices on daily walking journeys and prevention of slip and falls. The respondents were divided into three groups: an Intervention Group, a Control Group, with similar distribution of gender and age, and a Comparison Group. Four questionnaires were distributed: (1) background, (2) daily diary of distance walked and occurrence of incidents or accidents reported weekly, (3) detailed incident or fall report and (4) experiences of using anti-slip devices for those who used these devices during the trial period. Half of the respondents stated that they had previous experience of using anti-slip devices. In this study, 52% of the respondents used anti-slip devices. Anti-slip devices improve the walking capability during wintertime. Among those using appropriate anti-slip devices, the average daily walking distance was found to be statistically significantly longer compared to people not using anti-slip devices. This study indicates that an increase in daily walking distance can be made without increasing the risk of slips/falls when using anti-slip devices. The study also indicates that by using appropriate anti-slip devices and having information about when and where to use them, based on their design, people avoid having slips and falls. The respondents experienced in using anti-slip devices in this study will continue to use them and will also recommend others to use anti-slip devises. Copyright 2010 Elsevier Ltd. All rights

  17. Slow slip phenomena in Cascadia from 2007 and beyond: a review

    Science.gov (United States)

    Gomberg, Joan; ,

    2010-01-01

    Recent technological advances combined with more detailed analyses of seismologic and geodetic observations have fundamentally changed our understanding of the ways in which tectonic stresses arising from plate motions are accommodated by slip on faults. The traditional view that relative plate motions are accommodated by a simple cycle of stress accumulation and release on “locked” plate-boundary faults has been revolutionized by the serendipitous discovery and recognition of the significance of slow-slip phenomena, mostly in the deeper reaches of subduction zones. The Cascadia subduction zone, located in the Pacific Northwest of the conterminous United States and adjacent Canada, is an archetype of exploration and learning about slow-slip phenomena. These phenomena are manifest as geodetically observed aseismic transient deformations accompanied by a previously unrecognized class of seismic signals. Although secondary failure processes may be involved in generating the seismic signals, the primary origins of both aseismic and seismic phenomena appear to be episodic fault slip, probably facilitated by fluids, on a plate interface that is critically stressed or weakened. In Cascadia, this transient slip evolves more slowly and over more prolonged durations relative to the slip in earthquakes, and it occurs between the 30- and 40-km-depth contours of the plate interface where information was previously elusive. Although there is some underlying organization that relaxes nearly all the accrued plate-motion stresses along the entirety of Cascadia, we now infer that slow slip evolves in complex patterns indicative of propagating stress fronts. Our new understanding provides key constraints not only on the region where the slow slip originates, but also on the probable characteristics of future megathrust earthquakes in Cascadia. Herein, we review the most significant scientific issues and progress related to understanding slow-slip phenomena in Cascadia and

  18. Closed central slip injuries--a missed diagnosis?

    LENUS (Irish Health Repository)

    Nugent, N

    2011-09-01

    The extensor apparatus of the finger is a complex structure and injury can lead to significant digital dysfunction. Closed central slip injuries may be missed or diagnosis delayed because of lack of an open wound and often no radiographic abnormality, and can result in boutonniere deformities if untreated. This study aimed to quantify the number of patients attending with closed central slip injuries and to ascertain if the initial diagnosis was correct. The number of patients presenting to us over a 6 month period was recorded. The original diagnosis, time to diagnosis of central slip injury and the presence\\/absence of a boutonniere deformity were recorded. Ten patients were included in the study. Seven (70%) injuries were due to sport. Eight (80%) had a delayed diagnosis of central slip injury. Six (60%) had previously presented to general practitioners or emergency departments. Seven (70%) had boutonniere deformities. Closed central slip injuries can be missed. Simple clinical tests can diagnose central slip disruption.

  19. Variable slip-rate and slip-per-event on a plate boundary fault: The Dead Sea fault in northern Israel

    Science.gov (United States)

    Wechsler, Neta; Rockwell, Thomas K.; Klinger, Yann

    2018-01-01

    We resolved displacement on buried stream channels that record the past 3400 years of slip history for the Jordan Gorge (JGF) section of the Dead Sea fault in Israel. Based on three-dimensional (3D) trenching, slip in the past millennium amounts to only 2.7 m, similar to that determined in previous studies, whereas the previous millennium experienced two to three times this amount of displacement with nearly 8 m of cumulative slip, indicating substantial short term variations in slip rate. The slip rate averaged over the past 3400 years, as determined from 3D trenching, is 4.1 mm/yr, which agrees well with geodetic estimates of strain accumulation, as well as with longer-term geologic slip rate estimates. Our results indicate that: 1) the past 1200 years appear to significantly lack slip, which may portend a significant increase in future seismic activity; 2) short-term slip rates for the past two millennia have varied by more than a factor of two and suggest that past behavior is best characterized by clustering of earthquakes. From these observations, the earthquake behavior of the Jordan Gorge fault best fits is a "weak segment model" where the relatively short fault section (20 km), bounded by releasing steps, fails on its own in moderate earthquakes, or ruptures with adjacent segments.

  20. Automated identification and modeling aseismic slip events on Kilauea Volcano, Hawaii

    Science.gov (United States)

    Desmarais, E. K.; Segall, P.; Miklius, A.

    2006-12-01

    Several aseismic slip events have been observed on the south flank of Kilauea volcano, Hawaii (Cervelli et al., Nature, 2002; Brooks et al., EPSL, 2006; Segall et al., Nature, 2006). These events are identified as spatially coherent offsets in GPS time series. We have interpreted the events as slip on a sub-horizontal surface at depths consistent with a decollement under Kilauea's south flank. In order to determine whether smaller slow slip events are present in the time series, we developed an algorithm that searches for coherent displacement patterns similar to the known slow slip events. We compute candidate displacements by taking a running difference of the mean position 6 days before and after a window of 6 days centered on the candidate time step. The candidate displacements are placed in a 3N dimensional data vector, where N is the number of stations. We then compute the angle, in the 3N dimensional data space, between the candidate displacement and a reference vector at each time step. The reference vector is a stack of displacements due to the four largest known slow slip events. Small angles indicate similar displacement patterns, regardless of amplitude. The algorithm strongly identifies four events (September 20, 1998, November 9, 2000, December 16, 2002, and January 26, 2005), each separated by approximately 2.11 years. The algorithm also identified one smaller event (March 3, 1998) that preceeded the September 1998 event by ~ 200 days, and another event (July 4, 2003) that followed the December 2002 event by ~ 200 days. These smaller, 'paired' events appear to alternate rupturing of the eastern and western parts of the south flank. Each of the slow slip events is correlated with an increase, sometimes slight, in microseismicity on the south flank of Kilauea. The temporal evolution of the microseismicity for the 2005 event is well explained by increased stress due to the slow slip (Segall et al., Nature, 2006). The microearthquakes, at depths of 6

  1. Misbheaving Faults: The Expanding Role of Geodetic Imaging in Unraveling Unexpected Fault Slip Behavior

    Science.gov (United States)

    Barnhart, W. D.; Briggs, R.

    2015-12-01

    Geodetic imaging techniques enable researchers to "see" details of fault rupture that cannot be captured by complementary tools such as seismology and field studies, thus providing increasingly detailed information about surface strain, slip kinematics, and how an earthquake may be transcribed into the geological record. For example, the recent Haiti, Sierra El Mayor, and Nepal earthquakes illustrate the fundamental role of geodetic observations in recording blind ruptures where purely geological and seismological studies provided incomplete views of rupture kinematics. Traditional earthquake hazard analyses typically rely on sparse paleoseismic observations and incomplete mapping, simple assumptions of slip kinematics from Andersonian faulting, and earthquake analogs to characterize the probabilities of forthcoming ruptures and the severity of ground accelerations. Spatially dense geodetic observations in turn help to identify where these prevailing assumptions regarding fault behavior break down and highlight new and unexpected kinematic slip behavior. Here, we focus on three key contributions of space geodetic observations to the analysis of co-seismic deformation: identifying near-surface co-seismic slip where no easily recognized fault rupture exists; discerning non-Andersonian faulting styles; and quantifying distributed, off-fault deformation. The 2013 Balochistan strike slip earthquake in Pakistan illuminates how space geodesy precisely images non-Andersonian behavior and off-fault deformation. Through analysis of high-resolution optical imagery and DEMs, evidence emerges that a single fault map slip as both a strike slip and dip slip fault across multiple seismic cycles. These observations likewise enable us to quantify on-fault deformation, which account for ~72% of the displacements in this earthquake. Nonetheless, the spatial distribution of on- and off-fault deformation in this event is highly spatially variable- a complicating factor for comparisons

  2. Effect of polymer melt wall slip on the flow balance of profile extrusion dies

    Science.gov (United States)

    Carneiro, Olga S.; Ferrás, Luís L.; Pinho, Fernando T.; Nóbrega, João M.

    2013-04-01

    This work describes the implementation of the wall slip boundary condition in an in-house developed 3D numerical code based on the Finite Volume Method. For this purpose, several phenomenological models relating the velocity and the shear stress at the wall were implemented. This new feature is verified using a simple case study, by comparing the numerical results with those obtained through the corresponding analytical solution. Then, the potentialities of the new code are illustrated performing flow simulations of a polymer melt in a complex flow channel. The results obtained show that the slip at the wall influences the flow distribution at the die flow channel outlet. Therefore, and to assess the relevance of slippage in the optimal die geometry, the automatic optimization of a die flow channel, required for the production of a specific thermoplastic profile, is performed using both the no-slip and slip boundary conditions, together with two alternative optimization strategies. It is shown that slip favors the flow balance of the dies and also other issues of its performance.

  3. Effective slip for Stokes flow between two grooved walls with an arbitrary phase shift

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Chiu-On, E-mail: cong@hku.hk [Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong)

    2017-04-15

    This work aims to determine how the effective slip length for a wall-bounded flow may depend on, among other geometrical parameters, the phase shift between patterns on the two walls. An analytical model is developed for Stokes flow through a channel bounded by walls patterned with a regular array of rectangular ribs and grooves, where the patterns on the two walls can be misaligned by any phase shift. This study incorporates several previous studies as limiting or special cases. It is shown that the phase shift can have qualitatively different effects on the flow rate and effective slip length, depending on the flow direction. In a narrow channel, increasing the phase shift may mildly decrease the flow rate and effective slip length for flow parallel to the grooves, but can dramatically increase the flow rate and effective slip length for flow transverse to the grooves. It is found that unless the channel height is much larger than the period of the wall pattern, the effect due to wall confinement has to be taken into account on evaluating the effective slip lengths. (paper)

  4. Influence of Microtexture on Early Plastic Slip Activity in Ti-6Al-4V Polycrystals

    Science.gov (United States)

    Hémery, Samuel; Dang, Van Truong; Signor, Loïc; Villechaise, Patrick

    2018-06-01

    Microtextured regions are known to influence the fatigue performance of titanium alloys. Previous studies revealed that crack initiation, accounting for most of the fatigue life, is triggered by slip activity. The influence of microtextured regions on the early plastic slip activity was presently investigated by means of an in situ tensile test performed inside a scanning electron microscope on a bimodal Ti-6Al-4V polycrystalline specimen. A slip trace analysis was carried out in several regions with different crystallographic textures to highlight potentially different deformation behaviors. Significant stress heterogeneities were revealed through an early slip activation in microtextured regions with a predominant [0001] orientation. This point was shown to be related to a locally increased resolved shear stress. Consequences on behavior under cyclic loadings are finally discussed.

  5. Earthquake scaling laws for rupture geometry and slip heterogeneity

    Science.gov (United States)

    Thingbaijam, Kiran K. S.; Mai, P. Martin; Goda, Katsuichiro

    2016-04-01

    We analyze an extensive compilation of finite-fault rupture models to investigate earthquake scaling of source geometry and slip heterogeneity to derive new relationships for seismic and tsunami hazard assessment. Our dataset comprises 158 earthquakes with a total of 316 rupture models selected from the SRCMOD database (http://equake-rc.info/srcmod). We find that fault-length does not saturate with earthquake magnitude, while fault-width reveals inhibited growth due to the finite seismogenic thickness. For strike-slip earthquakes, fault-length grows more rapidly with increasing magnitude compared to events of other faulting types. Interestingly, our derived relationship falls between the L-model and W-model end-members. In contrast, both reverse and normal dip-slip events are more consistent with self-similar scaling of fault-length. However, fault-width scaling relationships for large strike-slip and normal dip-slip events, occurring on steeply dipping faults (δ~90° for strike-slip faults, and δ~60° for normal faults), deviate from self-similarity. Although reverse dip-slip events in general show self-similar scaling, the restricted growth of down-dip fault extent (with upper limit of ~200 km) can be seen for mega-thrust subduction events (M~9.0). Despite this fact, for a given earthquake magnitude, subduction reverse dip-slip events occupy relatively larger rupture area, compared to shallow crustal events. In addition, we characterize slip heterogeneity in terms of its probability distribution and spatial correlation structure to develop a complete stochastic random-field characterization of earthquake slip. We find that truncated exponential law best describes the probability distribution of slip, with observable scale parameters determined by the average and maximum slip. Applying Box-Cox transformation to slip distributions (to create quasi-normal distributed data) supports cube-root transformation, which also implies distinctive non-Gaussian slip

  6. Stick-slip substructure in rapid tape peeling

    KAUST Repository

    Thoroddsen, Sigurdur T.

    2010-10-15

    The peeling of adhesive tape is known to proceed with a stick-slip mechanism and produces a characteristic ripping sound. The peeling also produces light and when peeled in a vacuum, even X-rays have been observed, whose emissions are correlated with the slip events. Here we present direct imaging of the detachment zone when Scotch tape is peeled off at high speed from a solid surface, revealing a highly regular substructure, during the slip phase. The typical 4-mm-long slip region has a regular substructure of transverse 220 μm wide slip bands, which fracture sideways at speeds over 300 m/s. The fracture tip emits waves into the detached section of the tape at ∼100 m/s, which promotes the sound, so characteristic of this phenomenon.

  7. Stick-slip substructure in rapid tape peeling

    KAUST Repository

    Thoroddsen, Sigurdur T; Nguyen, H. D.; Takehara, K.; Etoh, T. G.

    2010-01-01

    The peeling of adhesive tape is known to proceed with a stick-slip mechanism and produces a characteristic ripping sound. The peeling also produces light and when peeled in a vacuum, even X-rays have been observed, whose emissions are correlated with the slip events. Here we present direct imaging of the detachment zone when Scotch tape is peeled off at high speed from a solid surface, revealing a highly regular substructure, during the slip phase. The typical 4-mm-long slip region has a regular substructure of transverse 220 μm wide slip bands, which fracture sideways at speeds over 300 m/s. The fracture tip emits waves into the detached section of the tape at ∼100 m/s, which promotes the sound, so characteristic of this phenomenon.

  8. Modeling of rock friction 2. Simulation of preseismic slip

    International Nuclear Information System (INIS)

    Dieterich, J.H.

    1979-01-01

    The constitutive relations developed in the companion paper are used to model detailed observations of preseismic slip and the onset of unstable slip in biaxial laboratory experiments. The simulations employ a deterministic plane strain finite element model to represent the interactions both within the sliding blocks and between the blocks and the loading apparatus. Both experiments and simulations show that preseismic slip controlled by initial inhomogeneity of shear stress along the sliding surface relative to the frictional strength. As a consequence of the inhomogeneity, stable slip begins at a point on the surface and the area of slip slowly expands as the external loading increases. A previously proposed correlation between accelerating rates of stable slip and growth of the area of slip is supported by the simulations. In the simulations and in the experiments, unstable slip occurs, shortly after a propagating slip event traverses the sliding surface and breaks out at the ends of the sample. In the model the breakout of stable slip causes a sudden acceleration of slip rates. Because of velocity dependency of the constitutive relationship for friction, the rapid acceleration of slip causes a decrease in frictional strength. Instability occurs when the frictional strength decreases with displacement at a rate that exceeds the intrinsic unloading characteristics of the sample and test machine. A simple slider-spring model that does not consider preseismic slip appears to approximate the transition adequately from stable sliding to unstable slip as a function of normal stress machine stiffness, and surface roughness for small samples. However, for large samples and for natural faults the simulations suggest that the simple model may be inaccurate because it does not take into account potentially large preseismic displacements that will alter the friction parameters prior to instability

  9. 76 FR 37620 - Risk-Based Capital Standards: Advanced Capital Adequacy Framework-Basel II; Establishment of a...

    Science.gov (United States)

    2011-06-28

    ... advanced approaches rules, several commenters, mostly representing the largest U.S. financial institutions... principles for preparing financial statements instead of the statutory accounting principles applicable to...-Based Capital Standards: Advanced Capital Adequacy Framework--Basel II; Establishment of a Risk-Based...

  10. Slip activity of persistent slip bands in polycrystalline nickel

    International Nuclear Information System (INIS)

    Weidner, A.; Beyer, R.; Blochwitz, C.; Holste, C.; Schwab, A.; Tirschler, W.

    2006-01-01

    The appearance of glide localizations after cyclic deformation in the saturation stage was investigated for polycrystalline nickel. It was shown that persistent slip bands (PSBs) are formed in a wide range of grain orientations. Concerning the grain size it was found, that the probability for the appearance of PSBs is higher for larger grains. The local slip activity of the formed PSBs was studied after half-cycle deformation using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The fraction of grains with glide-active PSBs and the glide-active PSB volume itself is very small after the half-cycle loading. The obtained local shear strain amplitudes are quite high and vary in the range of 0.2-5%. They are comparable with those found in nickel single crystals at the same loading procedure

  11. High tsunami frequency as a result of combined strike-slip faulting and coastal landslides

    Science.gov (United States)

    Hornbach, Matthew J.; Braudy, Nicole; Briggs, Richard W.; Cormier, Marie-Helene; Davis, Marcy B.; Diebold, John B.; Dieudonne, Nicole; Douilly, Roby; Frohlich, Cliff; Gulick, Sean P.S.; Johnson, Harold E.; Mann, Paul; McHugh, Cecilia; Ryan-Mishkin, Katherine; Prentice, Carol S.; Seeber, Leonardo; Sorlien, Christopher C.; Steckler, Michael S.; Symithe, Steeve Julien; Taylor, Frederick W.; Templeton, John

    2010-01-01

    Earthquakes on strike-slip faults can produce devastating natural hazards. However, because they consist predominantly of lateral motion, these faults are rarely associated with significant uplift or tsunami generation. And although submarine slides can generate tsunami, only a few per cent of all tsunami are believed to be triggered in this way. The 12 January Mw 7.0 Haiti earthquake exhibited primarily strike-slip motion but nevertheless generated a tsunami. Here we present data from a comprehensive field survey that covered the onshore and offshore area around the epicentre to document that modest uplift together with slope failure caused tsunamigenesis. Submarine landslides caused the most severe tsunami locally. Our analysis suggests that slide-generated tsunami occur an order-of-magnitude more frequently along the Gonave microplate than global estimates predict. Uplift was generated because of the earthquake's location, where the Caribbean and Gonave microplates collide obliquely. The earthquake also caused liquefaction at several river deltas that prograde rapidly and are prone to failure. We conclude that coastal strike-slip fault systems such as the Enriquillo-Plantain Garden fault produce relief conducive to rapid sedimentation, erosion and slope failure, so that even modest predominantly strike-slip earthquakes can cause potentially catastrophic slide-generated tsunami - a risk that is underestimated at present.

  12. Structural setting and kinematics of Nubian fault system, SE Western Desert, Egypt: An example of multi-reactivated intraplate strike-slip faults

    Science.gov (United States)

    Sakran, Shawky; Said, Said Mohamed

    2018-02-01

    Detailed surface geological mapping and subsurface seismic interpretation have been integrated to unravel the structural style and kinematic history of the Nubian Fault System (NFS). The NFS consists of several E-W Principal Deformation Zones (PDZs) (e.g. Kalabsha fault). Each PDZ is defined by spectacular E-W, WNW and ENE dextral strike-slip faults, NNE sinistral strike-slip faults, NE to ENE folds, and NNW normal faults. Each fault zone has typical self-similar strike-slip architecture comprising multi-scale fault segments. Several multi-scale uplifts and basins were developed at the step-over zones between parallel strike-slip fault segments as a result of local extension or contraction. The NNE faults consist of right-stepping sinistral strike-slip fault segments (e.g. Sin El Kiddab fault). The NNE sinistral faults extend for long distances ranging from 30 to 100 kms and cut one or two E-W PDZs. Two nearly perpendicular strike-slip tectonic regimes are recognized in the NFS; an inactive E-W Late Cretaceous - Early Cenozoic dextral transpression and an active NNE sinistral shear.

  13. Development of compact slip detection sensor using dielectric elastomer

    Science.gov (United States)

    Choi, Jae-young; Hwang, Do-Yeon; Kim, Baek-chul; Moon, Hyungpil; Choi, Hyouk Ryeol; Koo, Ja Choon

    2015-04-01

    In this paper, we developed a resistance tactile sensor that can detect a slip on the surface of sensor structure. The presented sensor device has fingerprint-like structures that are similar with the role of the humans finger print. The resistance slip sensor that the novel developed uses acrylo-nitrile butadiene rubber (NBR) as a dielectric substrate and graphene as an electrode material. We can measure the slip as the structure of sensor makes a deformation and it changes the resistance through forming a new conductive route. To manufacture our sensor, we developed a new imprint process. By using this process, we can produce sensor with micro unit structure. To verify effectiveness of the proposed slip detection, experiment using prototype of resistance slip sensor is conducted with an algorithm to detect slip and slip is successfully detected. We will discuss the slip detection properties.

  14. Dynamical stability of slip-stacking particles

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, Jeffrey; Zwaska, Robert

    2014-09-01

    We study the stability of particles in slip-stacking configuration, used to nearly double proton beam intensity at Fermilab. We introduce universal area factors to calculate the available phase space area for any set of beam parameters without individual simulation. We find perturbative solutions for stable particle trajectories. We establish Booster beam quality requirements to achieve 97% slip-stacking efficiency. We show that slip-stacking dynamics directly correspond to the driven pendulum and to the system of two standing-wave traps moving with respect to each other.

  15. An Economic Viewpoint on Capitalism Bashing

    Directory of Open Access Journals (Sweden)

    Burnete Sorin

    2016-12-01

    Full Text Available In this paper I discuss two long disputed notions: that capitalism without crises is a fallacy respectively that capitalism bashing, however severe, will not endanger the system itself. Yet proving both is not an easy task since the capitalism issue has always been a cupellation of theory, ideology and political precepts, which are controversial and hard to disentangle. That capitalism detractors are numberless is a truism. Yet criticism against capitalism, however fierce, has always been clearly delineated. Not any more: globalization has rendered the picture dangerously fuzzy. It is now hard to ascertain whether someone who will harangue about the ostensible evils of globalization is also a declared anti-capitalist. The blend of capitalism and globalization seems to be pure dynamite.

  16. The "Network Ethic" and the New Spirit of Capitalism in French Sociology of Capitalism

    DEFF Research Database (Denmark)

    Jagd, Søren

    2005-01-01

    forms of organisation have received less attention. In this paper I discuss a recent French contribution to the analysis of the cultural aspects of networks: Boltanski & Chiapello’s book Le nouvel esprit du capitalisme (Boltanski and Chiapello 1999). The contribution is important for recent discussions...... of a network perspective on organisations in several ways. First, drawing on Weber’s earlier discussion of the rise of the capitalist spirit, Boltanski and Chiapello proposes an interesting theoretical model of the change of capitalism relating two different types of cultural elements: the ‘spirit...... of capitalism’ and criticism of capitalism to processes of change in the form of capitalism. Second, Boltanski and Chiapello directs a critical perspective on the emergent model of ‘network capitalism’ and its accompanying spirit applying the theoretical framework of ‘worlds of justification’ developed earlier...

  17. Numerical Simulations of Slow Stick Slip Events with PFC, a DEM Based Code

    Science.gov (United States)

    Ye, S. H.; Young, R. P.

    2017-12-01

    Nonvolcanic tremors around subduction zone have become a fascinating subject in seismology in recent years. Previous studies have shown that the nonvolcanic tremor beneath western Shikoku is composed of low frequency seismic waves overlapping each other. This finding provides direct link between tremor and slow earthquakes. Slow stick slip events are considered to be laboratory scaled slow earthquakes. Slow stick slip events are traditionally studied with direct shear or double direct shear experiment setup, in which the sliding velocity can be controlled to model a range of fast and slow stick slips. In this study, a PFC* model based on double direct shear is presented, with a central block clamped by two side blocks. The gauge layers between the central and side blocks are modelled as discrete fracture networks with smooth joint bonds between pairs of discrete elements. In addition, a second model is presented in this study. This model consists of a cylindrical sample subjected to triaxial stress. Similar to the previous model, a weak gauge layer at a 45 degrees is added into the sample, on which shear slipping is allowed. Several different simulations are conducted on this sample. While the confining stress is maintained at the same level in different simulations, the axial loading rate (displacement rate) varies. By varying the displacement rate, a range of slipping behaviour, from stick slip to slow stick slip are observed based on the stress-strain relationship. Currently, the stick slip and slow stick slip events are strictly observed based on the stress-strain relationship. In the future, we hope to monitor the displacement and velocity of the balls surrounding the gauge layer as a function of time, so as to generate a synthetic seismogram. This will allow us to extract seismic waveforms and potentially simulate the tremor-like waves found around subduction zones. *Particle flow code, a discrete element method based numerical simulation code developed by

  18. Stochastic Wheel-Slip Compensation Based Robot Localization and Mapping

    Directory of Open Access Journals (Sweden)

    SIDHARTHAN, R. K.

    2016-05-01

    Full Text Available Wheel slip compensation is vital for building accurate and reliable dead reckoning based robot localization and mapping algorithms. This investigation presents stochastic slip compensation scheme for robot localization and mapping. Main idea of the slip compensation technique is to use wheel-slip data obtained from experiments to model the variations in slip velocity as Gaussian distributions. This leads to a family of models that are switched depending on the input command. To obtain the wheel-slip measurements, experiments are conducted on a wheeled mobile robot and the measurements thus obtained are used to build the Gaussian models. Then the localization and mapping algorithm is tested on an experimental terrain and a new metric called the map spread factor is used to evaluate the ability of the slip compensation technique. Our results clearly indicate that the proposed methodology improves the accuracy by 72.55% for rotation and 66.67% for translation motion as against an uncompensated mapping system. The proposed compensation technique eliminates the need for extro receptive sensors for slip compensation, complex feature extraction and association algorithms. As a result, we obtain a simple slip compensation scheme for localization and mapping.

  19. Axisymmetric Tornado Simulations with a Semi-Slip Boundary

    Directory of Open Access Journals (Sweden)

    Brian H. Fiedler

    2017-12-01

    Full Text Available The structure of natural tornadoes and simulated analogs are sensitive to the lower boundary condition for friction. Three-dimensional numerical simulations of storms require a choice for turbulence parameterizations and resolution of wind near the lower boundary. This article explores some of the consequences of choices of a surface drag coefficient on the structure of a mature simulated tornado, using a conventional axisymmetric model. The surface drag parameterization is explored over the range of the semi-slip condition, including the extremes of no-slip and free-slip. A moderate semi-slip condition allows for an extreme pressure deficit, but without the unrealistic vortex breakdown of the no-slip condition.

  20. Dynamic slip of polydisperse linear polymers using partitioned plate

    Science.gov (United States)

    Ebrahimi, Marzieh; Konaganti, Vinod Kumar; Hatzikiriakos, Savvas G.

    2018-03-01

    The slip velocity of an industrial grade high molecular weight high-density polyethylene (HDPE) is studied in steady and dynamic shear experiments using a stress/strain controlled rotational rheometer equipped with a parallel partitioned plate geometry. Moreover, fluoroalkyl silane-based coating is used to understand the effect of surface energy on slip in steady and dynamic conditions. The multimode integral Kaye-Bernstein-Kearsley-Zapas constitutive model is applied to predict the transient shear response of the HDPE melt obtained from rotational rheometer. It is found that a dynamic slip model with a slip relaxation time is needed to adequately predict the experimental data at large shear deformations. Comparison of the results before and after coating shows that the slip velocity is largely affected by surface energy. Decreasing surface energy by coating increases slip velocity and decreases the slip relaxation time.

  1. Capital Structure, Strategic Competition, and Governance

    NARCIS (Netherlands)

    T.T. Nguyen (Thuy Thu)

    2008-01-01

    textabstractThis thesis consists of four studies on the interactions of capital structure and product market competition, and on several aspects of governance, firm financing and growth. The first study investigates how competitive behavior and market uncertainty affect the capital structure of a

  2. Earthquake source properties from instrumented laboratory stick-slip

    Science.gov (United States)

    Kilgore, Brian D.; McGarr, Arthur F.; Beeler, Nicholas M.; Lockner, David A.; Thomas, Marion Y.; Mitchell, Thomas M.; Bhat, Harsha S.

    2017-01-01

    Stick-slip experiments were performed to determine the influence of the testing apparatus on source properties, develop methods to relate stick-slip to natural earthquakes and examine the hypothesis of McGarr [2012] that the product of stiffness, k, and slip duration, Δt, is scale-independent and the same order as for earthquakes. The experiments use the double-direct shear geometry, Sierra White granite at 2 MPa normal stress and a remote slip rate of 0.2 µm/sec. To determine apparatus effects, disc springs were added to the loading column to vary k. Duration, slip, slip rate, and stress drop decrease with increasing k, consistent with a spring-block slider model. However, neither for the data nor model is kΔt constant; this results from varying stiffness at fixed scale.In contrast, additional analysis of laboratory stick-slip studies from a range of standard testing apparatuses is consistent with McGarr's hypothesis. kΔt is scale-independent, similar to that of earthquakes, equivalent to the ratio of static stress drop to average slip velocity, and similar to the ratio of shear modulus to wavespeed of rock. These properties result from conducting experiments over a range of sample sizes, using rock samples with the same elastic properties as the Earth, and scale-independent design practices.

  3. Stick-slip Cycles and Tidal Modulation of Ice Stream Flow

    Science.gov (United States)

    Lipovsky, B.; Dunham, E. M.

    2016-12-01

    The reactivation of a single dormant Antarctic ice stream would double the continent's mass imbalance. Despite importance of understanding the likelihood of such an event, direct observation of the basal processes that lead to the activation and stagnation of streaming ice are minimal. As the only ice stream undergoing stagnation, the Whillans Ice Plain (WIP) occupies a central role in our understanding of these subglacial processes. Complicating matters is the observation, from GPS records, that the WIP experiences most of its motion during episodes of rapid sliding. These sliding events are tidally modulated and separated by 12 hour periods of quiescence. We conduct numerical simulations of ice stream stick-slip cycles. Our simulations include rate- and state-dependent frictional sliding, tidal forcing, inertia, upstream loading in a cross-stream, thickness-averaged formulation. Our principal finding is that ice stream motion may respond to ocean tidal forcing with one of two end member behaviors. In one limit, tidally modulated slip events have rupture velocities that approach the shear wave speed and slip events have a duration that scales with the ice stream width divided by the shear wave speed. In the other limit, tidal modulation results in ice stream sliding velocities with lower amplitude variation but at much longer timescales, i.e. semi-diurnal and longer. This latter behavior more closely mimics the behavior of several active ice streams (Bindschadler, Rutford). We find that WIP slip events exist between these two end member behaviors: rupture velocities are far below the inertial limit yet sliding occurs only episodically. The continuum of sliding behaviors is governed by a critical ice stream width over which slip event nucleate. When the critical width is much longer than the ice stream width, slip events are unable to nucleate. The critical width depends on the subglacial effective pressure, ice thickness, and frictional and elastic constitutive

  4. Experimental investigation of flow and slip transition in nanochannels

    Science.gov (United States)

    Li, Zhigang; Li, Long; Mo, Jingwen

    2014-11-01

    Flow slip in nanochannels is sought in many applications, such as sea water desalination and molecular separation, because it can enhance fluid transport, which is essential in nanofluidic systems. Previous findings about the slip length for simple fluids at the nanoscale appear to be controversial. Some experiments and simulations showed that the slip length is independent of shear rate, which agrees with the prediction of classic slip theories. However, there is increasing work showing that slip length is shear rate dependent. In this work, we experimentally investigate the Poiseuille flows in nanochannels. It is found that the flow rate undergoes a transition between two linear regimes as the shear rate is varied. The transition indicates that the non-slip boundary condition is valid at low shear rate. When the shear rate is larger than a critical value, slip takes place and the slip length increases linearly with increasing shear rate before approaching a constant value. The results reported in this work can help advance the understanding of flow slip in nanochannels. This work was supported by the Research Grants Council of the Hong Kong Special Administrative Region under Grant Nos. 615710 and 615312. J. Mo was partially supported by the Postgraduate Scholarship through the Energy Program at HKUST.

  5. Economic analysis vs. capital-recovery requirements of power reactor decommissioning

    International Nuclear Information System (INIS)

    Ferguson, J.S.

    1980-01-01

    As a consultant to electric utilities the author often becomes involved in the development of policy for capital recovery and in the determination of depreciation rates that will implement the policy. Utility capital recovery is controlled by generally accepted depreciation accounting practices and by regulatory commission accounting rules and, as a result, can differ significantly from engineering economics. Those involved with decommissioning of power reactors should be aware of the depreciation accounting and regulatory framework that dictates capital recovery requirements, whether their involvement is related to engineering economics or capital recovery. This presentation defines that framework, points out several significant implications (particularly tax), describes several conforming capital-recovery methods, describes several techniques that have been used with the decommissioning component in economic analysis of alternative energy sources, and discusses why those involved in economic analysis should learn the accounting and regulatory framework for capital recovery

  6. Comparison of GPS and Quaternary slip rates: Insights from a new Quaternary fault database for Central Asia

    Science.gov (United States)

    Mohadjer, Solmaz; Ehlers, Todd; Bendick, Rebecca; Mutz, Sebastian

    2016-04-01

    Previous studies related to the kinematics of deformation within the India-Asia collision zone have relied on slip rate data for major active faults to test kinematic models that explain the deformation of the region. The slip rate data, however, are generally disputed for many of the first-order faults in the region (e.g., Altyn Tagh and Karakorum faults). Several studies have also challenged the common assumption that geodetic slip rates are representative of Quaternary slip rates. What has received little attention is the degree to which geodetic slip rates relate to Quaternary slip rates for active faults in the India-Asia collision zone. In this study, we utilize slip rate data from a new Quaternary fault database for Central Asia to determine the overall relationship between Quaternary and GPS-derived slip rates for 18 faults. The preliminary analysis investigating this relationship uses weighted least squares and a re-sampling analysis to test the sensitivity of this relationship to different data point attributes (e.g., faults associated with data points and dating methods used for estimating Quaternary slip rates). The resulting sample subsets of data points yield a maximum possible Pearson correlation coefficient of ~0.6, suggesting moderate correlation between Quaternary and GPS-derived slip rates for some faults (e.g., Kunlun and Longmen Shan faults). Faults with poorly correlated Quaternary and GPS-derived slip rates were identified and dating methods used for the Quaternary slip rates were examined. Results indicate that a poor correlation between Quaternary and GPS-derived slip rates exist for the Karakorum and Chaman faults. Large differences between Quaternary and GPS slip rates for these faults appear to be connected to qualitative dating of landforms used in the estimation of the Quaternary slip rates and errors in the geomorphic and structural reconstruction of offset landforms (e.g., offset terrace riser reconstructions for Altyn Tagh fault

  7. RETRAN dynamic slip model

    International Nuclear Information System (INIS)

    McFadden, J.H.; Paulsen, M.P.; Gose, G.C.

    1981-01-01

    A time dependent equation for the slip velocity in a two-phase flow condition has been incorporated into a developmental version of the RETRAN computer code. This model addition has been undertaken to remove a limitation in RETRAN-01 associated with the homogeneous equilibrium mixture model. In this paper, the development of the slip model is summarized and the corresponding constitutive equations are discussed. Comparisons of RETRAN analyses with steady-state void fraction data and data from the Semiscale S-02-6 small break test are also presented

  8. RETRAN dynamic slip model

    International Nuclear Information System (INIS)

    McFadden, J.H.; Paulsen, M.P.; Gose, G.C.

    1981-01-01

    Thermal-hydraulic codes in general use for system calculations are based on extensive analyses of loss-of-coolant accidents following the postulated rupture of a large coolant pipe. In this study, time-dependent equation for the slip velocity in a two-phase flow condition has been incorporated into the RETRAN-02 computer code. This model addition was undertaken to remove a limitation in RETRAN-01 associated with the homogeneous equilibrium mixture model. The dynamic slip equation was derived from a set of two-fluid conservation equations. 18 refs

  9. Slip-mediated dewetting of polymer microdroplets

    Science.gov (United States)

    McGraw, Joshua D.; Chan, Tak Shing; Maurer, Simon; Salez, Thomas; Benzaquen, Michael; Raphaël, Elie; Brinkmann, Martin; Jacobs, Karin

    2016-01-01

    Classical hydrodynamic models predict that infinite work is required to move a three-phase contact line, defined here as the line where a liquid/vapor interface intersects a solid surface. Assuming a slip boundary condition, in which the liquid slides against the solid, such an unphysical prediction is avoided. In this article, we present the results of experiments in which a contact line moves and where slip is a dominating and controllable factor. Spherical cap-shaped polystyrene microdroplets, with nonequilibrium contact angle, are placed on solid self-assembled monolayer coatings from which they dewet. The relaxation is monitored using in situ atomic force microscopy. We find that slip has a strong influence on the droplet evolutions, both on the transient nonspherical shapes and contact line dynamics. The observations are in agreement with scaling analysis and boundary element numerical integration of the governing Stokes equations, including a Navier slip boundary condition. PMID:26787903

  10. Identification of slip surface location by TLS-GPS datafor landslide mitigation case study: Ciloto-Puncak, West Java

    Energy Technology Data Exchange (ETDEWEB)

    Sadarviana, Vera, E-mail: vsadarviana@gmail.com; Hasanuddin, A. Z.; Joenil, G. K.; Irwan; Wijaya, Dudy; Ilman, H.; Agung, N.; Achmad, R. T.; Pangeran, C.; Martin, S.; Gamal, M. [Geodesy Research Group, Faculty of Earth Sciences and Technology, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132, West Java (Indonesia); Santoso, Djoko [Geophysics Engineering Research Group, Faculty of Geoscience and Mineral Engineering, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132, West Java (Indonesia)

    2015-04-24

    Landslide can prevented by understanding the direction of movement to the safety evacuation track or slip surface location to hold avalanches. Slip surface is separating between stable soil and unstable soil in the slope. The slip surface location gives information about stable material depth. The information can be utilize to mitigate technical step, such as pile installation to keep construction or settlement safe from avalanches.There are two kinds landslide indicators which are visualization and calculation. By visualization, landslide identified from soil crack or scarp. Scarp is a scar of exposed soil on the landslide. That identification can be done by Terrestrial Laser Scanner (TLS) Image. Shape of scarp shows type of slip surface, translation or rotational. By calculation, kinematic and dynamic mathematic model will give vector, velocity and acceleration of material movement. In this calculation need velocity trend line at GPS point from five GPS data campaign. From intersection of trend lines it will create curves or lines of slip surface location. The number of slip surface can be known from material movement direction in landslide zone.Ciloto landslide zone have complicated phenomenon because that zone have influence from many direction of ground water level pressure. The pressure is causes generating several slip surface in Ciloto zone. Types of Ciloto slip surface have mix between translational and rotational type.

  11. Identification of slip surface location by TLS-GPS datafor landslide mitigation case study: Ciloto-Puncak, West Java

    International Nuclear Information System (INIS)

    Sadarviana, Vera; Hasanuddin, A. Z.; Joenil, G. K.; Irwan; Wijaya, Dudy; Ilman, H.; Agung, N.; Achmad, R. T.; Pangeran, C.; Martin, S.; Gamal, M.; Santoso, Djoko

    2015-01-01

    Landslide can prevented by understanding the direction of movement to the safety evacuation track or slip surface location to hold avalanches. Slip surface is separating between stable soil and unstable soil in the slope. The slip surface location gives information about stable material depth. The information can be utilize to mitigate technical step, such as pile installation to keep construction or settlement safe from avalanches.There are two kinds landslide indicators which are visualization and calculation. By visualization, landslide identified from soil crack or scarp. Scarp is a scar of exposed soil on the landslide. That identification can be done by Terrestrial Laser Scanner (TLS) Image. Shape of scarp shows type of slip surface, translation or rotational. By calculation, kinematic and dynamic mathematic model will give vector, velocity and acceleration of material movement. In this calculation need velocity trend line at GPS point from five GPS data campaign. From intersection of trend lines it will create curves or lines of slip surface location. The number of slip surface can be known from material movement direction in landslide zone.Ciloto landslide zone have complicated phenomenon because that zone have influence from many direction of ground water level pressure. The pressure is causes generating several slip surface in Ciloto zone. Types of Ciloto slip surface have mix between translational and rotational type

  12. Multiparameter Monitoring and Prevention of Fault-Slip Rock Burst

    Directory of Open Access Journals (Sweden)

    Shan-chao Hu

    2017-01-01

    Full Text Available Fault-slip rock burst is one type of the tectonic rock burst during mining. A detailed understanding of the precursory information of fault-slip rock burst and implementation of monitoring and early warning systems, as well as pressure relief measures, are essential to safety production in deep mines. This paper first establishes a mechanical model of stick-slip instability in fault-slip rock bursts and then reveals the failure characteristics of the instability. Then, change rule of mining-induced stress and microseismic signals before the occurrence of fault-slip rock burst are proposed, and multiparameter integrated early warning methods including mining-induced stress and energy are established. Finally, pressure relief methods targeting large-diameter boreholes and coal seam infusion are presented in accordance with the occurrence mechanism of fault-slip rock burst. The research results have been successfully applied in working faces 2310 of the Suncun Coal Mine, and the safety of the mine has been enhanced. These research results improve the theory of fault-slip rock burst mechanisms and provide the basis for prediction and forecasting, as well as pressure relief, of fault-slip rock bursts.

  13. Frictional melting and stick-slip behavior in volcanic conduits

    Science.gov (United States)

    Kendrick, Jackie Evan; Lavallee, Yan; Hirose, Takehiro; di Toro, Giulio; Hornby, Adrian Jakob; Hess, Kai-Uwe; Dingwell, Donald Bruce

    2013-04-01

    Dome-building eruptions have catastrophic potential, with dome collapse leading to devastating pyroclastic flows with almost no precursory warning. During dome growth, the driving forces of the buoyant magma may be superseded by controls along conduit margins; where brittle fracture and sliding can lead to formation of lubricating cataclasite and gouge. Under extreme friction, pseudotachylyte may form at the conduit margin. Understanding the conduit margin processes is vital to understanding the continuation of an eruption and we postulate that pseudotachylyte generation could be the underlying cause of stick-slip motion and associated seismic "drumbeats", which are so commonly observed at dome-building volcanoes. This view is supported by field evidence in the form of pseudotachylytes identified in lava dome products at Soufrière Hills (Montserrat) and Mount St. Helens (USA). Both eruptions were characterised by repetitive, periodic seismicity and lava spine extrusion of highly viscous magma. High velocity rotary shear (HVR) experiments demonstrate the propensity for melting of the andesitic and dacitic material (from Soufrière Hills and Mount St. Helens respectively) at upper conduit stress conditions (HVR experiments which mimic rapid velocity fluctuations in stick-slip behavior demonstrate velocity-weakening behavior of melt, with a tendency for unstable slip. During ascent, magma may slip and undergo melting along the conduit margin. In the process the shear resistance of the slip zone is increased, acting as a viscous brake halting slip (the "stick" of stick-slip motion). Sufficient buoyancy-driven pressures from ascending magma below eventually overcome resistance to produce a rapid slip event (the "slip") along the melt-bearing slip zone, which is temporarily lubricated due to velocity-weakening. New magma below experiences the same slip event more slowly (as the magma decompresses) to produce a viscous brake and the process is repeated. This allows a

  14. No slip gravity

    Science.gov (United States)

    Linder, Eric V.

    2018-03-01

    A subclass of the Horndeski modified gravity theory we call No Slip Gravity has particularly interesting properties: 1) a speed of gravitational wave propagation equal to the speed of light, 2) equality between the effective gravitational coupling strengths to matter and light, Gmatter and Glight, hence no slip between the metric potentials, yet difference from Newton's constant, and 3) suppressed growth to give better agreement with galaxy clustering observations. We explore the characteristics and implications of this theory, and project observational constraints. We also give a simple expression for the ratio of the gravitational wave standard siren distance to the photon standard candle distance, in this theory and others, and enable a direct comparison of modified gravity in structure growth and in gravitational waves, an important crosscheck.

  15. Slip behaviour of experimental faults subjected to fluid pressure stimulation: carbonates vs. shales

    Science.gov (United States)

    Collettini, C.; Scuderi, M. M.; Marone, C.

    2017-12-01

    Fluid overpressure is one of the primary mechanisms for triggering tectonic fault slip and human-induced seismicity. This mechanism has been invoked to explain the dramatic increase in seismicity associated with waste water disposal in intra-plate setting, and it is appealing because fluids lubricate the fault and reduce the effective normal stress that holds the fault in place. Although, this basic physical mechanism is well understood, several fundamental questions remain including the apparent delay between fluid injection and seismicity, the role of fault zone rheology, and the relationship between injection volume and earthquake size. Moreover, models of earthquake nucleation predict that a reduction in normal stress, as expected for fluid overpressure, should stabilize fault slip. Here, we address these questions using laboratory experiments, conducted in the double direct shear configuration in a true-triaxial machine on carbonates and shale fault gouges. In particular, we: 1) evaluate frictional strength and permeability, 2) characterize the rate- and state- friction parameters and 3) study fault slip evolution during fluid pressure stimulations. With increasing fluid pressure, when shear and effective normal stresses reach the failure condition, in calcite gouges, characterized by slightly velocity strengthening behaviour, we observe an acceleration of slip that spontaneously evolves into dynamic failure. For shale gouges, with a strong rate-strengthening behaviour, we document complex fault slip behavior characterized by periodic accelerations and decelerations with slip velocity that remains slow (i.e. v 200 µm/s), never approaching dynamic slip rates. Our data indicate that fault rheology and fault stability is controlled by the coupling between fluid pressure and rate- and state- friction parameters suggesting that their comprehensive characterization is fundamental for assessing the role of fluid pressure in natural and human induced earthquakes.

  16. Slip patterns and preferred dislocation boundary planes

    DEFF Research Database (Denmark)

    Winther, G.

    2003-01-01

    The planes of deformation induced extended planar dislocation boundaries are analysed in two different co-ordinate systems, namely the macroscopic system defined by the deformation axes and the crystallographic system given by the crystallographic lattice. The analysis covers single and polycryst......The planes of deformation induced extended planar dislocation boundaries are analysed in two different co-ordinate systems, namely the macroscopic system defined by the deformation axes and the crystallographic system given by the crystallographic lattice. The analysis covers single...... and polycrystals of fcc metals in three deformation modes (rolling, tension and torsion). In the macroscopic system, boundaries lie close to the macroscopically most stressed planes. In the crystallographic system, the boundary plane depends on the grain/crystal orientation. The boundary planes in both co......-ordinate systems are rationalised based on the slip. The more the slip is concentrated on a slip plane, the closer the boundaries lie to this. The macroscopic preference arises from the macroscopic directionality of the slip. The established relations are applied to (a) prediction of boundary planes from slip...

  17. Slip transmission in bcc FeCr polycrystal

    Energy Technology Data Exchange (ETDEWEB)

    Patriarca, Luca, E-mail: luca.patriarca@polimi.it [Politecnico di Milano, Department of Mechanical Engineering, Via La Masa 34, I-20156 Milano (Italy); Abuzaid, Wael; Sehitoglu, Huseyin [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206W. Green St., Urbana, IL 61801 (United States); Maier, Hans J. [Institut für Werkstoffkunde, Leibniz Universität Hannover, An der Universität 2, D-30823 Garbsen (Germany)

    2013-12-20

    Grain boundaries induce heterogeneities in the deformation response of polycrystals. Studying these local variations in response, measured through high resolution strain measurement techniques, is important and can improve our understanding of fatigue damage initiation in the vicinity of grain boundaries and material hardening. In this work, strain fields across grain boundaries were measured using advanced digital image correlation techniques. In conjunction with strain measurements, grain orientations from electron back-scattered diffraction were used to establish the dislocation reactions at each boundary, providing the corresponding residual Burgers vectors due to slip transmission across the interfaces. A close correlation was found between the magnitude of the residual Burgers vector and the local strain change across the boundary. When the residual Burgers vector magnitude (with respect to the lattice spacing) exceeds 1.0, the high strains on one side of the boundary are paired with low strains across the boundary, indicating the difficulties for slip dislocations to penetrate the grain interfaces. When the residual Burgers vector approaches zero, the strain fields vary smoothly across the boundary due to limited resistance to slip transmission. The results suggest that the residual Burgers vector magnitude, which relates to the GB (Grain Boundary) resistance to slip transmission, enables a quantitative analysis of the accumulation of strain at the microstructural level and the development of strain heterogeneities across grain boundaries. The results are presented for FeCr bcc alloy which exhibits single slip per grain making the measurements and dislocation reactions rather straightforward. The work points to the need to incorporate details of slip dislocation–grain boundary interaction (slip transmission) in modeling research.

  18. A Possible Differentially Shortened Strike-slip Plate Boundary: the Okhotsk Plate Example.

    Science.gov (United States)

    Hindle, D.; Egorov, V.; Mackey, K. G.; Fujita, K.

    2004-12-01

    The Okhotsk plate has been postulated based on a combination of GPS geodetic inversions (REVEL1), seimsicity, geologic and lineament data. Lying between the North American and Eurasian plates, its northwestern corner would appear to be undergoing compression in a scissors motion between the two bounding plates. Extrusion tectonics along multiple, large strike-slip faults within the Okhotsk plate itself have been suggested to allow the escape of material away from the apex of Eurasia-North America. The plate boundary between Okhotsk and North America has been suggested to be diffuse, based on widely scattered minor seismicity. However, the large, left lateral, Ulakhan fault has also been suggested as a candidate plate boundary. We present field geological and geomorphological evidence of the partitioning of deformation between the Ulakhan fault, and several parallel and oblique, linked faults. The Ulakhan fault strand appears to have a maximum displacement of 24 km based on river valley offsets and closing large pull apart basins. Some of the displacement from the Ulakhan fault appears relayed into the plate margin along oblique trending, thrust/oblique slip faults. Estimated shortening over these faults is equivalent to the amount of shortening relayed into the plate margin from the plate boundary. There may be several thrust/oblique slip faults along the Ulakhan fault, which leads to the interesting situation of a segmented, strike-slip plate boundary being actively shortened in a margin parallel direction. This may be the result of postulated extrusion of the Okhotsk plate due to North America/Eurasia convergence. Such a situation would have important consequences for the interpretation of GPS data in a plate tectonic context.

  19. Nonequilibrium Chromosome Looping via Molecular Slip Links

    Science.gov (United States)

    Brackley, C. A.; Johnson, J.; Michieletto, D.; Morozov, A. N.; Nicodemi, M.; Cook, P. R.; Marenduzzo, D.

    2017-09-01

    We propose a model for the formation of chromatin loops based on the diffusive sliding of molecular slip links. These mimic the behavior of molecules like cohesin, which, along with the CTCF protein, stabilize loops which contribute to organizing the genome. By combining 3D Brownian dynamics simulations and 1D exactly solvable nonequilibrium models, we show that diffusive sliding is sufficient to account for the strong bias in favor of convergent CTCF-mediated chromosome loops observed experimentally. We also find that the diffusive motion of multiple slip links along chromatin is rectified by an intriguing ratchet effect that arises if slip links bind to the chromatin at a preferred "loading site." This emergent collective behavior favors the extrusion of loops which are much larger than the ones formed by single slip links.

  20. Global capital markets: An updated profile

    Directory of Open Access Journals (Sweden)

    Filipović Miroslava

    2007-01-01

    Full Text Available More than two decades after the beginning of the financial revolution globalization of capital flows still attracts considerable attention, from both practitioners and academics. The aim of this paper is to contribute to understanding of some aspects of the global capital scene, as well as to emphasize certain developments which might illustrate its changing profile. Several fundamental perspectives profile the global capital market. A quantitative review provides a sense of sheer volumes, trends, origins and destinations of capital flows; an assessment of the global capital market’s degree of integration follows. The emergence of new (types of actors is another important aspect of the global processes, while illustrations of new market products and emerging segments may add new perspectives on the profile of the global capital market. Finally, the paper concludes with a brief overview of digitalization of the financial supply chain.

  1. Preliminary soil-slip susceptibility maps, southwestern California

    Science.gov (United States)

    Morton, Douglas M.; Alvarez, Rachel M.; Campbell, Russell H.; Digital preparation by Bovard, Kelly R.; Brown, D.T.; Corriea, K.M.; Lesser, J.N.

    2003-01-01

    This group of maps shows relative susceptibility of hill slopes to the initiation sites of rainfall-triggered soil slip-debris flows in southwestern California. As such, the maps offer a partial answer to one part of the three parts necessary to predict the soil-slip/debris-flow process. A complete prediction of the process would include assessments of “where”, “when”, and “how big”. These maps empirically show part of the “where” of prediction (i.e., relative susceptibility to sites of initiation of the soil slips) but do not attempt to show the extent of run out of the resultant debris flows. Some information pertinent to “when” the process might begin is developed. “When” is determined mostly by dynamic factors such as rainfall rate and duration, for which local variations are not amenable to long-term prediction. “When” information is not provided on the maps but is described later in this narrative. The prediction of “how big” is addressed indirectly by restricting the maps to a single type of landslide process—soil slip-debris flows. The susceptibility maps were created through an iterative process from two kinds of information. First, locations of sites of past soil slips were obtained from inventory maps of past events. Aerial photographs, taken during six rainy seasons that produced abundant soil slips, were used as the basis for soil slip-debris flow inventory. Second, digital elevation models (DEM) of the areas that were inventoried were used to analyze the spatial characteristics of soil slip locations. These data were supplemented by observations made on the ground. Certain physical attributes of the locations of the soil-slip debris flows were found to be important and others were not. The most important attribute was the mapped bedrock formation at the site of initiation of the soil slip. However, because the soil slips occur in surficial materials overlying the bedrocks units, the bedrock formation can only serve as

  2. Relation between boundary slip mechanisms and waterlike fluid behavior

    Science.gov (United States)

    Ternes, Patricia; Salcedo, Evy; Barbosa, Marcia C.

    2018-03-01

    The slip of a fluid layer in contact with a solid confining surface is investigated for different temperatures and densities using molecular dynamic simulations. We show that for an anomalous waterlike fluid the slip goes as follows: for low levels of shear, defect slip appears and is related to the particle exchange between the fluid layers; at high levels of shear, global slip occurs and is related to the homogeneous distribution of the fluid in the confining surfaces. The oscillations in the transition velocity from defect to global slip are shown to be associated with changes in the layering distribution in the anomalous fluid.

  3. Stress near geometrically complex strike-slip faults - Application to the San Andreas fault at Cajon Pass, southern California

    Science.gov (United States)

    Saucier, Francois; Humphreys, Eugene; Weldon, Ray, II

    1992-01-01

    A model is presented to rationalize the state of stress near a geometrically complex major strike-slip fault. Slip on such a fault creates residual stresses that, with the occurrence of several slip events, can dominate the stress field near the fault. The model is applied to the San Andreas fault near Cajon Pass. The results are consistent with the geological features, seismicity, the existence of left-lateral stress on the Cleghorn fault, and the in situ stress orientation in the scientific well, found to be sinistral when resolved on a plane parallel to the San Andreas fault. It is suggested that the creation of residual stresses caused by slip on a wiggle San Andreas fault is the dominating process there.

  4. Slip-stacking Dynamics for High-Power Proton Beams at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, Jeffrey Scott [Indiana Univ., Bloomington, IN (United States)

    2015-12-01

    Slip-stacking is a particle accelerator configuration used to store two particle beams with different momenta in the same ring. The two beams are longitudinally focused by two radiofrequency (RF) cavities with a small frequency difference between them. Each beam is synchronized to one RF cavity and perturbed by the other RF cavity. Fermilab uses slip-stacking in the Recycler so as to double the power of the 120 GeV proton beam in the Main Injector. This dissertation investigates the dynamics of slip-stacking beams analytically, numerically and experimentally. In the analytic analysis, I find the general trajectory of stable slip-stacking particles and identify the slip-stacking parametric resonances. In the numerical analysis, I characterize the stable phase-space area and model the particle losses. In particular, I evaluate the impact of upgrading the Fermilab Booster cycle-rate from 15 Hz to 20 Hz as part of the Proton Improvement Plan II (PIP-II). The experimental analysis is used to verify my approach to simulating slip-stacking loss. I design a study for measuring losses from the longitudinal single-particle dynamics of slip-stacking as a function of RF cavity voltage and RF frequency separation. I further propose the installation of a harmonic RF cavity and study the dynamics of this novel slip-stacking configuration. I show the harmonic RF cavity cancels out parametric resonances in slip-stacking, reduces emittance growth during slip-stacking, and dramatically enhances the stable phase-space area. The harmonic cavity is expected to reduce slip-stacking losses to far exceed PIP-II requirements. These results raise the possibility of extending slip-stacking beyond the PIP-II era.

  5. Slip parameters on major thrusts at a convergent plate boundary: regional heterogeneity of potential slip distance at the shallow portion of the subducting plate

    Science.gov (United States)

    Mukoyoshi, Hideki; Kaneki, Shunya; Hirono, Tetsuro

    2018-03-01

    Understanding variations of slip distance along major thrust systems at convergent margins is an important issue for evaluation of near-trench slip and the potential generation of large tsunamis. We derived quantitative estimates of slip along ancient subduction fault systems by using the maturity of carbonaceous material (CM) of discrete slip zones as a proxy for temperature. We first obtained the Raman spectra of CM in ultracataclasite and pseudotachylyte layers in discrete slip zones at depths below the seafloor of 1-4 km and 2.5-5.5 km, respectively. By comparing the area-under-the-peak ratios of graphitic and disordered bands in those Raman spectra with spectra of experimentally heated CM from surrounding rocks, we determined that the ultracataclasite and pseudotachylyte layers had been heated to temperatures of up to 700 and 1300 °C, respectively. Numerical simulation of the thermal history of CM extracted from rocks near the two slip zones, taking into consideration these temperature constraints, indicated that slip distances in the ultracataclasite and pseudotachylyte layers were more than 3 and 7 m, respectively. Thus, potential distance of coseismic slip along the subduction-zone fault system could have regional variations even at shallow depth (≤ 5.5 km). The slip distances we determined probably represent minimum slips for subduction-zone thrusts and thus provide an important contribution to earthquake preparedness plans in coastal areas facing the Nankai and Sagami Troughs.

  6. Recent Progress on Modeling Slip Deformation in Shape Memory Alloys

    Science.gov (United States)

    Sehitoglu, H.; Alkan, S.

    2018-03-01

    This paper presents an overview of slip deformation in shape memory alloys. The performance of shape memory alloys depends on their slip resistance often quantified through the Critical Resolved Shear Stress (CRSS) or the flow stress. We highlight previous studies that identify the active slip systems and then proceed to show how non- Schmid effects can be dominant in shape memory slip behavior. The work is mostly derived from our recent studies while we highlight key earlier works on slip deformation. We finally discuss the implications of understanding the role of slip on curtailing the transformation strains and also the temperature range over which superelasticity prevails.

  7. Recent Progress on Modeling Slip Deformation in Shape Memory Alloys

    Science.gov (United States)

    Sehitoglu, H.; Alkan, S.

    2018-03-01

    This paper presents an overview of slip deformation in shape memory alloys. The performance of shape memory alloys depends on their slip resistance often quantified through the Critical Resolved Shear Stress (CRSS) or the flow stress. We highlight previous studies that identify the active slip systems and then proceed to show how non-Schmid effects can be dominant in shape memory slip behavior. The work is mostly derived from our recent studies while we highlight key earlier works on slip deformation. We finally discuss the implications of understanding the role of slip on curtailing the transformation strains and also the temperature range over which superelasticity prevails.

  8. Foreshocks during the nucleation of stick-slip instability

    Science.gov (United States)

    McLaskey, Gregory C.; Kilgore, Brian D.

    2013-01-01

    We report on laboratory experiments which investigate interactions between aseismic slip, stress changes, and seismicity on a critically stressed fault during the nucleation of stick-slip instability. We monitor quasi-static and dynamic changes in local shear stress and fault slip with arrays of gages deployed along a simulated strike-slip fault (2 m long and 0.4 m deep) in a saw cut sample of Sierra White granite. With 14 piezoelectric sensors, we simultaneously monitor seismic signals produced during the nucleation phase and subsequent dynamic rupture. We observe localized aseismic fault slip in an approximately meter-sized zone in the center of the fault, while the ends of the fault remain locked. Clusters of high-frequency foreshocks (Mw ~ −6.5 to −5.0) can occur in this slowly slipping zone 5–50 ms prior to the initiation of dynamic rupture; their occurrence appears to be dependent on the rate at which local shear stress is applied to the fault. The meter-sized nucleation zone is generally consistent with theoretical estimates, but source radii of the foreshocks (2 to 70 mm) are 1 to 2 orders of magnitude smaller than the theoretical minimum length scale over which earthquake nucleation can occur. We propose that frictional stability and the transition between seismic and aseismic slip are modulated by local stressing rate and that fault sections, which would typically slip aseismically, may radiate seismic waves if they are rapidly stressed. Fault behavior of this type may provide physical insight into the mechanics of foreshocks, tremor, repeating earthquake sequences, and a minimum earthquake source dimension.

  9. Spatial and Temporal Variations in Slip Partitioning During Oblique Convergence Experiments

    Science.gov (United States)

    Beyer, J. L.; Cooke, M. L.; Toeneboehn, K.

    2017-12-01

    Physical experiments of oblique convergence in wet kaolin demonstrate the development of slip partitioning, where two faults accommodate strain via different slip vectors. In these experiments, the second fault forms after the development of the first fault. As one strain component is relieved by one fault, the local stress field then favors the development of a second fault with different slip sense. A suite of physical experiments reveals three styles of slip partitioning development controlled by the convergence angle and presence of a pre-existing fault. In experiments with low convergence angles, strike-slip faults grow prior to reverse faults (Type 1) regardless of whether the fault is precut or not. In experiments with moderate convergence angles, slip partitioning is dominantly controlled by the presence of a pre-existing fault. In all experiments, the primarily reverse fault forms first. Slip partitioning then develops with the initiation of strike-slip along the precut fault (Type 2) or growth of a secondary reverse fault where the first fault is steepest. Subsequently, the slip on the first fault transitions to primarily strike-slip (Type 3). Slip rates and rakes along the slip partitioned faults for both precut and uncut experiments vary temporally, suggesting that faults in these slip-partitioned systems are constantly adapting to the conditions produced by slip along nearby faults in the system. While physical experiments show the evolution of slip partitioning, numerical simulations of the experiments provide information about both the stress and strain fields, which can be used to compute the full work budget, providing insight into the mechanisms that drive slip partitioning. Preliminary simulations of precut experiments show that strain energy density (internal work) can be used to predict fault growth, highlighting where fault growth can reduce off-fault deformation in the physical experiments. In numerical simulations of uncut experiments with a

  10. A flexible slip sensor using triboelectric nanogenerator approach

    Science.gov (United States)

    Wang, Xudong; Liang, Jiaming; Xiao, Yuxiang; Wu, Yichuan; Deng, Yang; Wang, Xiaohao; Zhang, Min

    2018-03-01

    With the rapid development of robotic technology, tactile sensors for robots have gained great attention from academic and industry researchers. Tactile sensors for slip detection are essential for human-like steady control in dexterous robot hand. In this paper, we propose and demonstrate a flexible slip sensor based on triboelectric nanogenerator with a seesaw structure. The sensor is composed of two porous PDMS layers separated by an inverted trapezoid structure with a height of 500 μm. In order to customize the sensitivity of the sensor, porous PDMS was fabricated by mixing PDMS with deionized water thoroughly and then removing water with heat. Laser-induced porous graphene and aluminium are served as the pair of contact materials. To detect slip from different directions, two sets of the electrode pair were used. Experimental results show a distinct difference between static state and the moment when a slip happens was detected. In addition, the output voltage of the sensors increased as the increase of slip velocity from 0.25 mm/s to 2.5 mm/s. The flexible slip sensor proposed here shows the potential applications in smart robotics and prosthesis.

  11. Multiparameter Monitoring and Prevention of Fault-Slip Rock Burst

    OpenAIRE

    Hu, Shan-chao; Tan, Yun-liang; Ning, Jian-guo; Guo, Wei-Yao; Liu, Xue-sheng

    2017-01-01

    Fault-slip rock burst is one type of the tectonic rock burst during mining. A detailed understanding of the precursory information of fault-slip rock burst and implementation of monitoring and early warning systems, as well as pressure relief measures, are essential to safety production in deep mines. This paper first establishes a mechanical model of stick-slip instability in fault-slip rock bursts and then reveals the failure characteristics of the instability. Then, change rule of mining-i...

  12. Boundary Slip and Surface Interaction: A Lattice Boltzmann Simulation

    International Nuclear Information System (INIS)

    Yan-Yan, Chen; Hua-Bing, Li; Hou-Hui, Yi

    2008-01-01

    The factors affecting slip length in Couette geometry flows are analysed by means of a two-phase mesoscopic lattice Boltzmann model including non-ideal fluid-fluid and fluid-wall interactions. The main factors influencing the boundary slip are the strength of interactions between fluid-fluid and fluid-wall particles. Other factors, such as fluid viscosity, bulk pressure may also change the slip length. We find that boundary slip only occurs under a certain density (bulk pressure). If the density is large enough, the slip length will tend to zero. In our simulations, a low density layer near the wall does not need to be postulated a priori but emerges naturally from the underlying non-ideal mesoscopic dynamics. It is the low density layer that induces the boundary slip. The results may be helpful to understand recent experimental observations on the slippage of micro flows

  13. Asymmetrical slip propensity: required coefficient of friction.

    Science.gov (United States)

    Seo, Jung-suk; Kim, Sukwon

    2013-07-31

    Most studies in performing slips and falls research reported their results after the ipsilateral leg of subjects (either right foot or left foot) was guided to contact the contaminated floor surface although many studies indicated concerns for asymmetries of legs in kinematic or kinetic variables. Thus, the present study evaluated if dominant leg's slip tendency would be different from non-dominant leg's slip tendency by comparing the Required Coefficient of Friction (RCOF) of the two lower limbs. Forty seven health adults participated in the present study. RCOF was measured when left or right foot of subjects contacted the force platforms respectively. Paired t-test was performed to test if RCOF and heel velocity (HCV) of dominant legs was different from that of non-dominant legs. It was suggested that the asymmetry in RCOFs and HCV between the two lower limbs existed. The RCOFs of non-dominant legs were higher than that of dominant legs. The results indicated that asymmetry in slip propensity, RCOF, was existed in lower extremity. The results from the study suggested that it would be benefit to include a variable, such as asymmetry, in slips and falls research.

  14. The Slip Behavior and Source Parameters for Spontaneous Slip Events on Rough Faults Subjected to Slow Tectonic Loading

    Science.gov (United States)

    Tal, Yuval; Hager, Bradford H.

    2018-02-01

    We study the response to slow tectonic loading of rough faults governed by velocity weakening rate and state friction, using a 2-D plane strain model. Our numerical approach accounts for all stages in the seismic cycle, and in each simulation we model a sequence of two earthquakes or more. We focus on the global behavior of the faults and find that as the roughness amplitude, br, increases and the minimum wavelength of roughness decreases, there is a transition from seismic slip to aseismic slip, in which the load on the fault is released by more slip events but with lower slip rate, lower seismic moment per unit length, M0,1d, and lower average static stress drop on the fault, Δτt. Even larger decreases with roughness are observed when these source parameters are estimated only for the dynamic stage of the rupture. For br ≤ 0.002, the source parameters M0,1d and Δτt decrease mutually and the relationship between Δτt and the average fault strain is similar to that of a smooth fault. For faults with larger values of br that are completely ruptured during the slip events, the average fault strain generally decreases more rapidly with roughness than Δτt.

  15. Non-slipping domains of a pulled spool

    International Nuclear Information System (INIS)

    Wagner, Clemens; Vaterlaus, Andreas

    2014-01-01

    We have investigated the pulled spool by considering pulling angles up to 360 ∘ . Our focus was on downward pulling forces with pulling angles in the range of 180 ∘ to 360 ∘ . In this range we have found a domain of pulling angles where the spool never starts to slip independent of the strength of the pulling force. The size of the domain depends on the static friction coefficient and on the moment of inertia of the spool. The non-slipping domain is mainly formed around the critical angle where the static friction force becomes zero. For low static friction the non-slipping domain decays into two different domains. We have determined the limiting angles of the non-slipping domains and explored the transitions from a single domain to two separated domains in parameter space. (paper)

  16. CAPITAL STRUCTURE AND VENTURE CAPITAL

    Directory of Open Access Journals (Sweden)

    Becsky-Nagy Patricia

    2015-07-01

    Full Text Available Venture capital significantly changes the capital structure of the portfolio company at the time of the investment. Venture capitalists contribute to the company’s success through their active involvement in the management and their added value appears in the increase of the value of the equity. At the same time with taking active role in the management, agency problem occurs, that complicates the cooperation and the success of exit. In this article we search the answer for the question whether the preferred equity, that are commonly used in the US for bridging the agency problem, are used and able to help Hungarian venture capitalists to manage agency problems. On the other hand we examined how the venture capital affect capital structure, how the venture capitalists value added appear in the capital structure. During the evaluation of the three case studies, we came to the conclusion, that the venture capital investments have positive effect on the liabilities of the enterprises, as the capital structure indexes show. However, the investors need the ownership, which help them to step up resolutely, when things change for the worse, and companies need the expertise, which the investors bring with their personal assistance. The investor’s new attitude also has positive effect on a mature company, which has an experienced leader, because he can show another aspect, as a person who come from outside. During the examination of the capital structure, we cannot disregard the events of the company’s environment, which have effects on the firm. The investor’s decisions also appear different ways. Because of this, every venture capital investment is different, just as the capital structure of the firms, in which they invest.

  17. Early MRI Detection and Closed Bone Graft Epiphysiodesis May Alter the Course of Avascular Necrosis Following Unstable Slipped Capital Femoral Epiphysis.

    Science.gov (United States)

    Napora, Joshua K; Gilmore, Allison; Son-Hing, Jochen P; Grimberg, Dominic C; Thompson, George H; Liu, Raymond W

    2018-04-01

    Unstable slipped capital femoral epiphysis (SCFE) has an increased incidence of avascular necrosis (AVN). Early identification and surgical intervention for AVN may help preserve the femoral head. We retrospectively reviewed 48 patients (50 hips) with unstable SCFE managed between 2000 and 2014. AVN was diagnosed based on 2 different postoperative protocols. Seventeen patients (17 hips) had a scheduled magnetic resonance imaging (MRI) between 1 and 6 months from initial surgery, and the remaining 31 patients (33 hips) were evaluated by plain radiographs alone. If AVN was diagnosed, we offered core decompression and closed bone graft epiphysiodesis (CBGE) to mitigate its affects. At final follow-up, we assessed progression of AVN using the Steinberg classification. Overall 13 hips (26%) with unstable SCFEs developed AVN. MRI revealed AVN in 7 of 17 hips (41%) at a mean of 2.5 months postoperatively (range, 1.0 to 5.2 mo). Six hips diagnosed by MRI received surgical intervention (4 CBGE, 1 free vascularized fibula graft, and 1 repinning due to screw cutout) at a mean of 4.1 months (range, 1.3 to 7.2 mo) postoperatively. None of the 4 patients treated with CBGE within 2 months postoperatively progressed to stage IVC AVN. The 2 patients treated after 4 months postoperatively both progressed to stage VC AVN.Plain radiographs demonstrated AVN in 6 of 33 hips (18%) at a mean of 6.8 months postoperatively (range, 2.1 to 21.1 mo). One patient diagnosed with stage IVB AVN at 2.4 months had screw cutout and received CBGE at 2.5 months from initial pinning. The remaining 5 were not offered surgical intervention. Five of the 6 radiographically diagnosed AVN, including the 1 treated with CBGE, progressed to stage IVC AVN or greater. Although all patients with positive MRI scans developed radiographic AVN, none of the 4 patients treated with CBGE within 2 months after pinning developed grade IVC or greater AVN. Early MRI detection and CBGE may mitigate the effects of AVN after

  18. Short-and-long-term Slip Rates Along the Carboneras Fault in the Betic Cordillera, Spain

    Science.gov (United States)

    Khazaradze, G.; López, R.; Pallàs, R.; Ortuño, M.; Bordonau, J.; Masana, E.

    2017-12-01

    We present the new results from our long-standing studies to understand the geodynamic behavior of the Carboneras fault, located in the SE Betic Cordilleras of Spain. Specifically, we quantify the geodetic and geologic slip rates for the onland section of the fault. As a result of our previous GPS observations, we have been able to confirm the continuing tectonic activity of the Carboneras fault: we were able to quantify that the geodetic slip rate of the fault equals 1.3±0.2 mm/yr, expressed mainly as a left-lateral strike slip motion (Echeverria et al., 2015). In autumn 2017, with the purpose of revealing a detailed nature of the crustal deformation and its partitioning between different structures, 3 new continuous GPS stations will be established along the fault-perpendicular profile. In addition, since summer 2016, we have conducted surveys of the nearby CuaTeNeo and IGN Regente campaign points. We have also established and measured several new geodetic points in the vicinity of the fault, with the aim of increasing the spatial coverage around it. The GPS measured, short-term slip rates are in surprising agreement with the estimates of the long-term, geologic slip rates based on paleoseismic studies, which indicate a minimum strike-slip rate of 1.31 mm/yr and dip-slip rate of 0.05 mm/yr since 110.3 ka (Moreno et al. 2015). In order to increase the paleoseismic event database, several new sites have been identified along the fault, where further paleoseismic trenching surveys will be performed within the coming year or two. At the site of Tostana, located at the central part of the fault, in winter 2017 seven trenches have been opened and clear evidence of past earthquakes has been encountered. These new data, combined with the findings of the recent geomorphological study of river offsets (Ferrater, 2016) and new GPS observations, should improve the reliability of the existent deformation data and therefore, will help to better understand the seismic hazard

  19. Size-affected single-slip behavior of Rene N5 microcrystals

    Energy Technology Data Exchange (ETDEWEB)

    Shade, P.A., E-mail: paul.shade@wpafb.af.mil [Department of Materials Science and Engineering, Ohio State University, 477 Watts Hall, 2041 College Road, Columbus, OH 43210 (United States); Air Force Research Laboratory, Materials and Manufacturing Directorate, 2230 10th Street, Wright-Patterson AFB, OH 45433 (United States); Uchic, M.D.; Dimiduk, D.M. [Air Force Research Laboratory, Materials and Manufacturing Directorate, 2230 10th Street, Wright-Patterson AFB, OH 45433 (United States); Viswanathan, G.B.; Wheeler, R. [UES Inc., 4401 Dayton-Xenia Road, Dayton, OH 45432 (United States); Fraser, H.L. [Department of Materials Science and Engineering, Ohio State University, 477 Watts Hall, 2041 College Road, Columbus, OH 43210 (United States)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Microcompression testing was conducted on the single crystal superalloy Rene N5. Black-Right-Pointing-Pointer All microcrystals exhibited size-affected plastic flow. Black-Right-Pointing-Pointer Dendrite core microcrystals were stronger than those from interdendritic regions. - Abstract: Microcompression testing was conducted on the cast single crystal nickel-base superalloy Rene N5. Microcrystals were selectively fabricated from either dendrite core or interdendritic regions. The compression axis was oriented for single-slip deformation and microcrystal diameters ranged from 2.5 to 80 {mu}m. All microcrystals displayed several hallmarks of size-affected plastic flow, including a size-affected and stochastic flow-stress and initial strain hardening rate, as well as an intermittent flow response. The magnitude of size-affected flow-stress scaling behavior was dependent upon the plastic strain level of the flow-stress measurement, with increasing size-dependence for increasing strain levels. TEM analysis demonstrated the activation of multiple slip-systems, despite the microcrystals being oriented for single-slip deformation. Zig-zag slip was also observed in microcrystals that achieved flow stresses of {approx}1300 MPa or higher. For microcrystals fabricated within interdendritic regions the flow-stress values are, on average, lower compared to dendrite core microcrystals. This difference in flow-stress is especially pronounced for microcrystals which are 5 {mu}m in diameter. The microcrystal diameter for which bulk-like properties are estimated to be observed is approximately 350 {mu}m, which is approaching the measured primary dendrite arm spacing for this crystal (430 {mu}m).

  20. Seismic and Aseismic Slip on the Cascadia Megathrust

    Science.gov (United States)

    Michel, S. G. R. M.; Gualandi, A.; Avouac, J. P.

    2017-12-01

    Our understanding of the dynamics governing aseismic and seismic slip hinges on our ability to image the time evolution of fault slip during and in between earthquakes and transients. Such kinematic descriptions are also pivotal to assess seismic hazard as, on the long term, elastic strain accumulating around a fault should be balanced by elastic strain released by seismic slip and aseismic transients. In this presentation, we will discuss how such kinematic descriptions can be obtained from the analysis and modelling of geodetic time series. We will use inversion methods based on Independent Component Analysis (ICA) decomposition of the time series to extract and model the aseismic slip (afterslip and slow slip events). We will show that this approach is very effective to identify, and filter out, non-tectonic sources of geodetic strain such as the strain due to surface loads, which can be estimated using gravimetric measurements from GRACE, and thermal strain. We will discuss in particular the application to the Cascadia subduction zone.

  1. Transformation of fault slip modes in laboratory experiments

    Science.gov (United States)

    Martynov, Vasilii; Alexey, Ostapchuk; Markov, Vadim

    2017-04-01

    Slip mode of crust fault can vary because of many reasons. It's well known that fault structure, material of fault gouge, pore fluid et al. in many ways determines slip modes from creep and slow slip events to mega-earthquakes [1-3]. Therefore, the possibility of fault slip transformation due to external action is urgent question. There is popular and developing approach of fluid injection into central part of fault. The phenomenon of earthquakes induced due to pumping of water was investigated on small and large scales [4, 5]. In this work the laboratory experiments were conducted to study the evolution of the experimental fault slip when changing the properties of the interstitial fluid. The scheme of experiments is the classical slider-model set-up, in which the block under the shear force slips along the interface. In our experiments the plexiglas block 8x8x3 cm3 in size was put on the plexiglas base. The contact of the blocks was filled with a thin layer (about 3 mm thick) of a granular material. The normal load varied from 31 to 156 kPa. The shear load was applied through a spring with stiffness 60 kN/m, and the rate of spring deformation was 20 or 5 mcm/s. Two parameters were recorded during experiments: the shear force acting on the upper block (with an accuracy of 1 N) and its displacement relatively the base (with an accuracy of 0.1 μm). The gouge was composed of quartz sand (97.5%) and clay (2.5%). As a moisturizer were used different fluids with viscosity varying from 1 to 103 mPa x s. Different slip modes were simulated during slider-experiments. In our experiments slip mode is the act of instability manifested in an increase of slip velocity and a drop of shear stress acting on a movable block. The amplitude of a shear stress drop and the peak velocity of the upper block were chosen as the characteristics of the slip mode. In the laboratory experiments, slip events of one type can be achieved either as regularly recurring (regular mode) or as random

  2. Is Social Capital a Good Concept?

    DEFF Research Database (Denmark)

    Bjørnskov, Christian; Sønderskov, Kim Mannemar

    2013-01-01

    This paper explores whether the concept of social capital as popularized by Robert Putnam is a good social science concept. Taking Gerring’s work on concept evaluation as the starting point, the paper first presents a set of criteria for conceptual ‘goodness’ and discusses how social capital...... performs on these criteria. It is argued that social capital eventually may be a good concept if it can be shown empirically to be a unidimensional concept. An empirical section therefore explores the validity of the unidimensionality assumption and rejects it in four separate tests at both the individual...... and aggregate level. We conclude that even if social capital has been a remarkably productive idea, it is not a good concept as most popular conceptualizations define social capital as several distinct phenomena or as phenomena that already have been conceptualized under other labels....

  3. Development of microsized slip sensors using dielectric elastomer for incipient slippage

    Science.gov (United States)

    Hwang, Do-Yeon; Kim, Baek-chul; Cho, Han-Jeong; Li, Zhengyuan; Lee, Youngkwan; Nam, Jae-Do; Moon, Hyungpil; Choi, Hyouk Ryeol; Koo, J. C.

    2014-04-01

    A humanoid robot hand has received significant attention in various fields of study. In terms of dexterous robot hand, slip detecting tactile sensor is essential to grasping objects safely. Moreover, slip sensor is useful in robotics and prosthetics to improve precise control during manipulation tasks. In this paper, sensor based-human biomimetic structure is fabricated. We reported a resistance tactile sensor that enables to detect a slip on the surface of sensor structure. The resistance slip sensor that the novel developed uses acrylonitrile-butadiene rubber (NBR) as a dielectric substrate and carbon particle as an electrode material. The presented sensor device in this paper has fingerprint-like structures that are similar with the role of the human's finger print. It is possible to measure the slip as the structure of sensor makes a deformation and it changes the resistance through forming a new conductive route. To verify effectiveness of the proposed slip detection, experiment using prototype of resistance slip sensor is conducted with an algorithm to detect slip and slip was successfully detected. In this paper, we will discuss the slip detection properties so four sensor and detection principle.

  4. Factors associated with worker slipping in limited-service restaurants.

    Science.gov (United States)

    Courtney, Theodore K; Verma, Santosh K; Huang, Yueng-Hsiang; Chang, Wen-Ruey; Li, Kai Way; Filiaggi, Alfred J

    2010-02-01

    Slips, trips and falls (STF) are responsible for a substantial injury burden in the global workplace. Restaurant environments are challenged by STF. This study assessed individual and work environment factors related to slipping in US limited-service restaurant workers. Workers in 10 limited-service restaurants in Massachusetts were recruited to participate. Workers' occupational slip and/or fall history within the past 4 weeks was collected by multilingual written questionnaires. Age, gender, job tenure, work hours per week and work shift were also collected. Shoe type, condition and gross shoe contamination were visually assessed. Floor friction was measured and each restaurant's overall mean coefficient of friction (COF) was calculated. The logistic generalised estimating equations model was used to compute adjusted odds ratios (OR). Of 125 workers, 42 reported one or more slips in the past 4 weeks with two reporting a resultant fall. Results from multivariable regression showed that higher restaurant mean COF was significantly associated with a decreased risk of self-reported slipping (OR 0.59, 95% CI 0.42 to 0.82). From the highest to the lowest COF restaurant, the odds of a positive slip history increased by a factor of more than seven. Younger age, male gender, lower weekly work hours and the presence of gross contamination on worker's shoe sole were also associated with increased odds of slip history. Published findings of an association between friction and slipping and falling in actual work environments are rare. The findings suggest that effective intervention strategies to reduce the risk of slips and falls in restaurant workers could include increasing COF and improving housekeeping practices.

  5. Strike-slip faults offshore southern Taiwan: implications for the oblique arc-continent collision processes

    Science.gov (United States)

    Fuh, Shi-Chie; Liu, Char-Shine; Lundberg, Neil; Reed, Donald L.

    1997-06-01

    Taiwan is the site of present-day oblique arc-continent collision between the Luzon arc of the Philippine Sea plate and the Chinese continental margin. The major structural pattern revealed from marine geophysical studies in the area offshore southern Taiwan is that of a doubly-vergent orogenic belt, bounded by significant zones of thrusting on the west and east of the submarine accretionary wedge. Due to the oblique collision process, strike-slip faults could play an important role in this convergent domain. Topographic lineaments revealed from new digital bathymetry data and seismic reflection profiles confirm the existence of three sets of strike-slip faults in the collision-subduction zone offshore southern Taiwan: the N-S-trending left-lateral strike-slip faults within the Luzon volcanic arc, the NE-SW-trending right-lateral strike-slip faults across the accretionary wedge, and the NNE-SSW-trending left-lateral strike-slip faults lie in the frontal portion of the accretionary wedge. These strike-slip faults overprint pre-existing folds and thrusts and may convert into oblique thrusts or thrusts as the forearc blocks accrete to the mountain belt. A bookshelf rotation model is used to explain the observed geometrical relationships of these strike-slip fault systems. Based on this model, the counter-clockwise rotation of the forearc blocks in the area offshore southern Taiwan could have caused extrusion of the accretionary wedge material into the forearc basin. The originally continuous forearc basin is thus deformed into several closed and separate proto-collisional basins such as the Southern Longitudinal Trough and Taitung Trough. A tectonic evolution model which emphasizes on the development of various structures at different stages of the oblique arc-continent collision for the Taiwan mountain belt is proposed.

  6. Aseismic and seismic slip induced by fluid injection from poroelastic and rate-state friction modeling

    Science.gov (United States)

    Liu, Y.; Deng, K.; Harrington, R. M.; Clerc, F.

    2016-12-01

    Solid matrix stress change and pore pressure diffusion caused by fluid injection has been postulated as key factors for inducing earthquakes and aseismic slip on pre-existing faults. In this study, we have developed a numerical model that simulates aseismic and seismic slip in a rate-and-state friction framework with poroelastic stress perturbations from multi-stage hydraulic fracturing scenarios. We apply the physics-based model to the 2013-2015 earthquake sequences near Fox Creek, Alberta, Canada, where three magnitude 4.5 earthquakes were potentially induced by nearby hydraulic fracturing activity. In particular, we use the relocated December 2013 seismicity sequence to approximate the fault orientation, and find the seismicity migration spatiotemporally correlate with the positive Coulomb stress changes calculated from the poroelastic model. When the poroelastic stress changes are introduced to the rate-state friction model, we find that slip on the fault evolves from aseismic to seismic in a manner similar to the onset of seismicity. For a 15-stage hydraulic fracturing that lasted for 10 days, modeled fault slip rate starts to accelerate after 3 days of fracking, and rapidly develops into a seismic event, which also temporally coincides with the onset of induced seismicity. The poroelastic stress perturbation and consequently fault slip rate continue to evolve and remain high for several weeks after hydraulic fracturing has stopped, which may explain the continued seismicity after shut-in. In a comparison numerical experiment, fault slip rate quickly decreases to the interseismic level when stress perturbations are instantaneously returned to zero at shut-in. Furthermore, when stress perturbations are removed just a few hours after the fault slip rate starts to accelerate (that is, hydraulic fracturing is shut down prematurely), only aseismic slip is observed in the model. Our preliminary results thus suggest the design of fracturing duration and flow

  7. Geodetic Slip Solution for the Mw=7.4 Champerico (Guatemala) Earthquake of 07 November 2012

    Science.gov (United States)

    Ellis, A. P.; DeMets, C.; Briole, P.; Molina, E.; Flores, O.; Rivera, J.; Lasserre, C.; Lyon-Caen, H.; Lord, N. E.

    2014-12-01

    As the first large subduction thrust earthquake off the coast of western Guatemala in the past several decades, the 07 November 2012 Mw=7.4 earthquake offers the first opportunity for a geodetic study of coseismic and postseismic behavior for a segment of the Middle America trench where frictional coupling makes a transition from weak coupling off the coast of El Salvador to strong coupling in southern Mexico. We use measurements at 19 continuous GPS sites in Guatemala, El Salvador, and Mexico to estimate the coseismic slip and post-seismic deformation of the November 2012 Champerico (Guatemala) earthquake. Coseismic offsets range from ~47 mm near the epicenter to El Salvador. An inversion of the geodetic data indicate that that up to ~2 m of coseismic slip occurred on a ~30 km by 30 km rupture area between ~10 and 30 km depth, encouragingly close to the global CMT epicenter. The geodetic moment of 13 x 1019 N·m and corresponding magnitude of 7.4 both agree well with independent seismological estimates. An inversion for the postseismic fault afterslip shows that the transient postseismic motions recorded at 11 GPS sites are well fit with a logarithmically decaying function. More than 70 per cent of the postseismic slip occurred at the same depth or directly downdip from the main shock epicenter. At the upper limit, afterslip that occurred within 6 months of the earthquake released energy equivalent to only ~20 per cent of the coseismic moment. The seismologically derived slip solution from Ye et al. (2012), which features more highly concentrated slip than our own, fits our GPS offsets reasonably well provided that we translate their slip centroid ~51 km to the west to a position close to our own slip centroid. The geodetic and seismologic slip solutions thus suggest bounds of 2-5 m for the peak slip along a region of the interface no larger than 30 x 30 km and possibly much smaller.

  8. Fabrication of Y-TZP For Dental Crowns Applications by Combining Slip Casting and Cold Isostatic Pressing

    International Nuclear Information System (INIS)

    Hao, C.C.; Andanastuti Muchtar; Che Husna Azhari; Masfueh Razali; Mohamed Aboras

    2016-01-01

    Yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) is a popular material for dental restoration because of its outstanding mechanical properties and biocompatibility. Cold isostatic pressing (CIP) and slip casting are among several consolidation methods for Y-TZP. These methods produce Y-TZP with high mechanical properties. This study aims to enhance the mechanical properties of Y-TZP by combining slip casting and CIP. Y-TZP samples were fabricated using CIP, slip casting, and their combination. Subsequently, the green bodies of the samples were sintered at 1600 degree Celcius. Their mechanical properties (density and hardness) were tested and their microstructures were scrutinized under a scanning electron microscope. Compared with the other two methods, the combined method significantly improved the mechanical properties of Y-TZP. In addition, the combined method also produced a compact and homogeneous microstructure. Therefore, the combination of slip casting and CIP is recommended in the production of Y-TZP with high mechanical properties for dental crown applications. (author)

  9. Possible deep fault slip preceding the 2004 Parkfield earthquake, inferred from detailed observations of tectonic tremor

    Science.gov (United States)

    Shelly, David R.

    2009-01-01

    Earthquake predictability depends, in part, on the degree to which sudden slip is preceded by slow aseismic slip. Recently, observations of deep tremor have enabled inferences of deep slow slip even when detection by other means is not possible, but these data are limited to certain areas and mostly the last decade. The region near Parkfield, California, provides a unique convergence of several years of high-quality tremor data bracketing a moderate earthquake, the 2004 magnitude 6.0 event. Here, I present detailed observations of tectonic tremor from mid-2001 through 2008 that indicate deep fault slip both before and after the Parkfield earthquake that cannot be detected with surface geodetic instruments. While there is no obvious short-term precursor, I find unidirectional tremor migration accompanied by elevated tremor rates in the 3 months prior to the earthquake, which suggests accelerated creep on the fault ∼16 km beneath the eventual earthquake hypocenter.

  10. Performance analysis of a microcontroller based slip power recovery ...

    African Journals Online (AJOL)

    Slip power recovery wound rotor induction motor drives are used in high power, limited speed range applications where control of slip power provides the variable speed drive system. In this paper, the steady state performance analysis of conventional slip power recovery scheme using static line commutated inverter in the ...

  11. Vaporization of fault water during seismic slip

    Science.gov (United States)

    Chen, Jianye; Niemeijer, André R.; Fokker, Peter A.

    2017-06-01

    Laboratory and numerical studies, as well as field observations, indicate that phase transitions of pore water might be an important process in large earthquakes. We present a model of the thermo-hydro-chemo-mechanical processes, including a two-phase mixture model to incorporate the phase transitions of pore water, occurring during fast slip (i.e., a natural earthquake) in order to investigate the effects of vaporization on the coseismic slip. Using parameters from typical natural faults, our modeling shows that vaporization can indeed occur at the shallow depths of an earthquake, irrespective of the wide variability of the parameters involved (sliding velocity, friction coefficient, gouge permeability and porosity, and shear-induced dilatancy). Due to the fast kinetics, water vaporization can cause a rapid slip weakening even when the hydrological conditions of the fault zone are not favorable for thermal pressurization, e.g., when permeability is high. At the same time, the latent heat associated with the phase transition causes the temperature rise in the slip zone to be buffered. Our parametric analyses reveal that the amount of frictional work is the principal factor controlling the onset and activity of vaporization and that it can easily be achieved in earthquakes. Our study shows that coseismic pore fluid vaporization might have played important roles at shallow depths of large earthquakes by enhancing slip weakening and buffering the temperature rise. The combined effects may provide an alternative explanation for the fact that low-temperature anomalies were measured in the slip zones at shallow depths of large earthquakes.

  12. Report on the Aseismic Slip, Tremor, and Earthquakes Workshop

    Science.gov (United States)

    Gomberg, Joan; Roeloffs, Evelyn; Trehu, Anne; Dragert, Herb; Meertens, Charles

    2008-01-01

    This report summarizes the discussions and information presented during the workshop on Aseismic Slip, Tremor, and Earthquakes. Workshop goals included improving coordination among those involved in conducting research related to these phenomena, assessing the implications for earthquake hazard assessment, and identifying ways to capitalize on the education and outreach opportunities presented by these phenomena. Research activities of focus included making, disseminating, and analyzing relevant measurements; the relationships among tremor, aseismic or 'slow-slip', and earthquakes; and discovering the underlying causative physical processes. More than 52 participants contributed to the workshop, held February 25-28, 2008 in Sidney, British Columbia. The workshop was sponsored by the U.S. Geological Survey, the National Science Foundation?s Earthscope Program and UNAVCO Consortium, and the Geological Survey of Canada. This report has five parts. In the first part, we integrate the information exchanged at the workshop as it relates to advancing our understanding of earthquake generation and hazard. In the second part, we summarize the ideas and concerns discussed in workshop working groups on Opportunities for Education and Outreach, Data and Instrumentation, User and Public Needs, and Research Coordination. The third part presents summaries of the oral presentations. The oral presentations are grouped as they were at the workshop in the categories of phenomenology, underlying physical processes, and implications for earthquake hazards. The fourth part contains the meeting program and the fifth part lists the workshop participants. References noted in parentheses refer to the authors of presentations made at the workshop, and published references are noted in square brackets and listed in the Reference section. Appendix A contains abstracts of all participant presentations and posters, which also have been posted online, along with presentations and author contact

  13. Measurement and characterization of slippage and slip-law using a rigorous analysis in dynamics of oscillating rheometer: Newtonian fluid

    Science.gov (United States)

    Azese, Martin Ndi

    2018-02-01

    This article presents a rigorous calculation involving velocity slip of Newtonian fluid where we analyze and solve the unsteady Navier-Stokes equation with emphasis on its rheological implication. The goal of which is to model a simple yet effective non-invasive way of quantifying and characterizing slippage. Indeed this contrasts with previous techniques that exhibit inherent limitations whereby injecting foreign objects usually alter the flow. This problem is built on the Couette rheological flow system such that μ-Newton force and μ-stress are captured and processed to obtain wall slip. Our model leads to a linear partial differential equation and upon enforcing linear-Navier slip boundary conditions (BC) yields inhomogeneous and unsteady "Robin-type" BC. A dimensional analysis reveals salient dimensionless parameters: Roshko, Strouhal, and Reynolds while highlighting slip-numbers from BC. We also solve the slip-free case to corroborate and validate our results. Several graphs are generated showing slip effects, particularly, studying how slip-numbers, a key input, differentiate themselves to the outputs. We also confirm this in a graphical fashion by presenting the flow profile across channel width, velocity, and stress at both walls. A perturbation scheme is introduced to calculate long-time behavior when the system seats for long. More importantly, in the end, we justify the existence of a reverse mechanism, where an inverse transformation like Fourier transform uses the output data to retrieve slip-numbers and slip law, thus quantifying and characterizing slip. Therefore, we not only substantiate our analysis, but we also justify our claim, measurement and characterization, and theorize realizability of our proposition.

  14. Half-cycle slip activity of persistent slip bands at different stages of fatigue life of polycrystalline nickel

    Czech Academy of Sciences Publication Activity Database

    Weidner, A.; Man, Jiří; Tirschler, W.; Klapetek, P.; Blochwitz, C.; Polák, Jaroslav; Skrotzki, W.

    2008-01-01

    Roč. 492, č. 1-2 (2008), s. 118-127 ISSN 0921-5093 R&D Projects: GA ČR GA106/06/1096 Institutional research plan: CEZ:AV0Z20410507 Keywords : persistent slip band * slip activity * half-cycle deformation * atomic force microscopy * scanning electron microscopy * nickel Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.806, year: 2008

  15. Constraining the roughness degree of slip heterogeneity

    KAUST Repository

    Causse, Mathieu

    2010-05-07

    This article investigates different approaches for assessing the degree of roughness of the slip distribution of future earthquakes. First, we analyze a database of slip images extracted from a suite of 152 finite-source rupture models from 80 events (Mw = 4.1–8.9). This results in an empirical model defining the distribution of the slip spectrum corner wave numbers (kc) as a function of moment magnitude. To reduce the “epistemic” uncertainty, we select a single slip model per event and screen out poorly resolved models. The number of remaining models (30) is thus rather small. In addition, the robustness of the empirical model rests on a reliable estimation of kc by kinematic inversion methods. We address this issue by performing tests on synthetic data with a frequency domain inversion method. These tests reveal that due to smoothing constraints used to stabilize the inversion process, kc tends to be underestimated. We then develop an alternative approach: (1) we establish a proportionality relationship between kc and the peak ground acceleration (PGA), using a k−2 kinematic source model, and (2) we analyze the PGA distribution, which is believed to be better constrained than slip images. These two methods reveal that kc follows a lognormal distribution, with similar standard deviations for both methods.

  16. Slipped Capital Femoral Epiphysis

    Science.gov (United States)

    ... Kids and Teens Pregnancy and Childbirth Women Men Seniors Your Health Resources Healthcare Management End-of-Life Issues Insurance & Bills Self Care Working With Your Doctor Drugs, Procedures & Devices Over-the- ...

  17. Two long-term slow slip events around Tokyo Bay found by GNSS observation during 1996-2011

    Science.gov (United States)

    Tanaka, Yoshiyuki; Yabe, Suguru

    2017-03-01

    Slow slip events (SSEs) with durations ranging from days to more than a decade have been observed in plate subduction zones around the world. In the Kanto district in Japan, several SSEs have been identified based on geodetic observations. However, none of these events have had durations largely exceeding a year. In this study, we show that long-term SSEs with durations longer than 3 years occurred before the year 2000 and after 2007 on the upper interface of the Philippine Sea Plate at depths of 30-40 km. The fault model determined by inversion of global navigation satellite system data is located northeast of Tokyo Bay, where a seismic gap and low seismic wave velocities were detected by seismological observations. Moreover, the acceleration periods of the fault slip corresponded well with increases in the background seismicity for shallower earthquakes. The slip history was also temporally correlated with the long-term shear stress changes governed mainly by non-tidal variations in the ocean bottom pressure. However, the predicted slip from the long-term stress change was too small to reproduce the observed slow slips. To prove the causal relationship between the SSEs and the external stress change, more advanced modeling is necessary to confirm whether such a small slip can trigger an SSE.[Figure not available: see fulltext.

  18. Simulating spontaneous aseismic and seismic slip events on evolving faults

    Science.gov (United States)

    Herrendörfer, Robert; van Dinther, Ylona; Pranger, Casper; Gerya, Taras

    2017-04-01

    Plate motion along tectonic boundaries is accommodated by different slip modes: steady creep, seismic slip and slow slip transients. Due to mainly indirect observations and difficulties to scale results from laboratory experiments to nature, it remains enigmatic which fault conditions favour certain slip modes. Therefore, we are developing a numerical modelling approach that is capable of simulating different slip modes together with the long-term fault evolution in a large-scale tectonic setting. We extend the 2D, continuum mechanics-based, visco-elasto-plastic thermo-mechanical model that was designed to simulate slip transients in large-scale geodynamic simulations (van Dinther et al., JGR, 2013). We improve the numerical approach to accurately treat the non-linear problem of plasticity (see also EGU 2017 abstract by Pranger et al.). To resolve a wide slip rate spectrum on evolving faults, we develop an invariant reformulation of the conventional rate-and-state dependent friction (RSF) and adapt the time step (Lapusta et al., JGR, 2000). A crucial part of this development is a conceptual ductile fault zone model that relates slip rates along discrete planes to the effective macroscopic plastic strain rates in the continuum. We test our implementation first in a simple 2D setup with a single fault zone that has a predefined initial thickness. Results show that deformation localizes in case of steady creep and for very slow slip transients to a bell-shaped strain rate profile across the fault zone, which suggests that a length scale across the fault zone may exist. This continuum length scale would overcome the common mesh-dependency in plasticity simulations and question the conventional treatment of aseismic slip on infinitely thin fault zones. We test the introduction of a diffusion term (similar to the damage description in Lyakhovsky et al., JMPS, 2011) into the state evolution equation and its effect on (de-)localization during faster slip events. We compare

  19. Roman capitals from Sirmium (Sremska Mitrovica, Serbia

    Directory of Open Access Journals (Sweden)

    Maver Andreja

    2009-01-01

    Full Text Available The article brings a detailed formal analysis of the Roman capitals from Sirmium, in the light of the stone analysis conducted on the material at the Museum of Srem and elsewhere in Sremska Mitrovica. The capitals dot the historical development of the town from the first half of the 2nd century until the 4th century. First made of regional limestone, they were later joined by those of limestone and marbles of distant source, whereby different stones in capitals coexisted almost throughout the town’s development. This was certainly the situation during the flourishing times of the late 3rd and the 4th century, when Sirmium, as one of the four capitals of the Roman Empire, stood within several formal circles of capitals. The plain-leaved capitals tie it to the rest of Pannonia, the Corinthianizing capitals to the provinces to the east and south, while part of the Asiatic capitals, the largest group, tie it to the wider area of the Mediterranean.

  20. Tremor-genic slow slip regions may be deeper and warmer and may slip slower than non-tremor-genic regions

    Science.gov (United States)

    Montgomery-Brown, Emily; Syracuse, Ellen M.

    2015-01-01

    Slow slip events (SSEs) are observed worldwide and often coincide with tectonic tremor. Notable examples of SSEs lacking observed tectonic tremor, however, occur beneath Kīlauea Volcano, Hawaii, the Boso Peninsula, Japan, near San Juan Bautista on the San Andreas Fault, California, and recently in Central Ecuador. These SSEs are similar to other worldwide SSEs in many ways (e.g., size or duration), but lack the concurrent tectonic tremor observed elsewhere; instead, they trigger swarms of regular earthquakes. We investigate the physical conditions that may distinguish these non-tremor-genic SSEs from those associated with tectonic tremor, including slip velocity, pressure, temperature, fluids, and fault asperities, although we cannot eliminate the possibility that tectonic tremor may be obscured in highly attenuating regions. Slip velocities of SSEs at Kīlauea Volcano (∼10−6 m/s) and Boso Peninsula (∼10−7 m/s) are among the fastest SSEs worldwide. Kīlauea Volcano, the Boso Peninsula, and Central Ecuador are also among the shallowest SSEs worldwide, and thus have lower confining pressures and cooler temperatures in their respective slow slip zones. Fluids also likely contribute to tremor generation, and no corresponding zone of high vp/vs has been noted at Kīlauea or Boso. We suggest that the relatively faster slip velocities at Kīlauea Volcano and the Boso Peninsula result from specific physical conditions that may also be responsible for triggering swarms of regular earthquakes adjacent to the slow slip, while different conditions produce slower SSE velocities elsewhere and trigger tectonic tremor.

  1. The Earth isn't flat: The (large) influence of topography on geodetic fault slip imaging.

    Science.gov (United States)

    Thompson, T. B.; Meade, B. J.

    2017-12-01

    While earthquakes both occur near and generate steep topography, most geodetic slip inversions assume that the Earth's surface is flat. We have developed a new boundary element tool, Tectosaur, with the capability to study fault and earthquake problems including complex fault system geometries, topography, material property contrasts, and millions of elements. Using Tectosaur, we study the model error induced by neglecting topography in both idealized synthetic fault models and for the cases of the MW=7.3 Landers and MW=8.0 Wenchuan earthquakes. Near the steepest topography, we find the use of flat Earth dislocation models may induce errors of more than 100% in the inferred slip magnitude and rake. In particular, neglecting topographic effects leads to an inferred shallow slip deficit. Thus, we propose that the shallow slip deficit observed in several earthquakes may be an artefact resulting from the systematic use of elastic dislocation models assuming a flat Earth. Finally, using this study as an example, we emphasize the dangerous potential for forward model errors to be amplified by an order of magnitude in inverse problems.

  2. Slip flow in graphene nanochannels

    DEFF Research Database (Denmark)

    . Kannam, Sridhar; Billy, Todd; Hansen, Jesper Schmidt

    2011-01-01

    We investigate the hydrodynamic boundary condition for simple nanofluidic systems such as argon and methane flowing in graphene nanochannels using equilibrium molecular dynamics simulations (EMD) in conjunction with our recently proposed method [J. S. Hansen, B. D. Todd, and P. J. Daivis, Phys. Rev....... E 84, 016313 (2011)10.1103/PhysRevE.84.016313]. We first calculate the fluid-graphene interfacial friction coefficient, from which we can predict the slip length and the average velocity of the first fluid layer close to the wall (referred to as the slip velocity). Using direct nonequilibrium...

  3. Molecular Dynamics Simulations of Slip on Curved Surfaces

    Directory of Open Access Journals (Sweden)

    Ross D.A.

    2016-07-01

    Full Text Available We present Molecular Dynamics (MD simulations of liquid water confined within nanoscale geometries, including slit-like and cylindrical graphitic pores. These equilibrium results are used for calculating friction coefficients, which in turn can be used to calculate slip lengths. The slip length is a material property independent of the fluid flow rate. It is therefore a better quantity for study than the fluid velocity at the wall, also known as the slip velocity. Once the slip length has been found as a function of surface curvature, it can be used to parameterise Lattice Boltzmann (LB simulations. These larger scale simulations are able to tell us about how fluid transport is affected by slip in complex geometries; not just limited to single pores. Applications include flow and transport in nano-porous engine valve deposits and gas shales. The friction coefficient is found to be a function of curvature and is higher for fluid on convex surfaces and lower for concave surfaces. Both concave and convex surfaces approach the same value of the friction coefficient, which is constant above some critical radius of curvature, here found to be 7.4 ± 2.9 nm. The constant value of the friction coefficient is 10,000 ± 600 kg m−2 s−1, which is equivalent to a slip length of approximately 67 ± 4 nm.

  4. Shape fabric development in rigid clast populations under pure shear: The influence of no-slip versus slip boundary conditions

    Science.gov (United States)

    Mulchrone, Kieran F.; Meere, Patrick A.

    2015-09-01

    Shape fabrics of elliptical objects in rocks are usually assumed to develop by passive behavior of inclusions with respect to the surrounding material leading to shape-based strain analysis methods belonging to the Rf/ϕ family. A probability density function is derived for the orientational characteristics of populations of rigid ellipses deforming in a pure shear 2D deformation with both no-slip and slip boundary conditions. Using maximum likelihood a numerical method is developed for estimating finite strain in natural populations deforming for both mechanisms. Application to a natural example indicates the importance of the slip mechanism in explaining clast shape fabrics in deformed sediments.

  5. A Transformational Approach to Slip-Slide Factoring

    Science.gov (United States)

    Steckroth, Jeffrey

    2015-01-01

    In this "Delving Deeper" article, the author introduces the slip-slide method for solving Algebra 1 mathematics problems. This article compares the traditional method approach of trial and error to the slip-slide method of factoring. Tools that used to be taken for granted now make it possible to investigate relationships visually,…

  6. Next generation GNSS single receiver cycle slip reliability

    NARCIS (Netherlands)

    Teunissen, P.J.G.; De Bakker, P.F.

    2009-01-01

    In this contribution we study the multi-frequency, carrier-phase slip detection capabilities of a single receiver. Our analysis is based on an analytical expression that we present for themulti-frequencyminimal detectable carrier phase cycle slip.

  7. Cooperation, social capital and economic performance

    Directory of Open Access Journals (Sweden)

    Marcos Fernandes Gonçalves da Silva

    2006-09-01

    Full Text Available The objective of this paper is to define social capital as social infrastructure and to try to include this variable in an economic growth model. Considering social capital in such a way could have an impact on the productivity of production factors. Firstly, I will discuss how institutional variables can affect growth. Secondly, after analyzing several definitions of social capital, I will point out the benefits and problems of each one and will define social capital as social infrastructure, aiming to introduce this variable into an economic growth model. Finally, I will try to open the way for subsequent empirical studies, both in the area of measuring the stock of social infrastructure as well as those comparing economies, with the idea of showing the impact of social infrastructure on economic growth.

  8. WORLD ECONOMIC CRISIS, EXPRESSION OF THE GENERAL CRISIS CAPITALISM AND THE SITUATION WORKERS IN THE CLASS STRUGGLE AGAINST THE CAPITAL

    Directory of Open Access Journals (Sweden)

    Vicente E. Escandell-Sosa

    2016-01-01

    Full Text Available This work, based on the method dialectical materialist of Marx, argues with scientific approaches, that the world economic crisis, for very sharp and severe she is, is not a crisis without exit of the capitalism neither it will cause the collapse of the capitalism, although she constitutes part of the general crisis of the capitalism and increase the same one, since no crisis of the capitalism will take it to its end in absence of a fight of classes, because the social force that must generate the revolutionary changes is very limited. «Without the products of the fight of classes, the economic crises, «per se» won’t be a threat for the capital. The essential question is if the proletariat will live the crisis like object or like decisive fellow». The immaturity of the proletariat and its subordination to the laws of the capital indicate that the specific nature of the capital remains hidden.» 

  9. Size-affected single-slip behavior of René N5 microcrystals

    International Nuclear Information System (INIS)

    Shade, P.A.; Uchic, M.D.; Dimiduk, D.M.; Viswanathan, G.B.; Wheeler, R.; Fraser, H.L.

    2012-01-01

    Highlights: ► Microcompression testing was conducted on the single crystal superalloy René N5. ► All microcrystals exhibited size-affected plastic flow. ► Dendrite core microcrystals were stronger than those from interdendritic regions. - Abstract: Microcompression testing was conducted on the cast single crystal nickel-base superalloy René N5. Microcrystals were selectively fabricated from either dendrite core or interdendritic regions. The compression axis was oriented for single-slip deformation and microcrystal diameters ranged from 2.5 to 80 μm. All microcrystals displayed several hallmarks of size-affected plastic flow, including a size-affected and stochastic flow-stress and initial strain hardening rate, as well as an intermittent flow response. The magnitude of size-affected flow-stress scaling behavior was dependent upon the plastic strain level of the flow-stress measurement, with increasing size-dependence for increasing strain levels. TEM analysis demonstrated the activation of multiple slip-systems, despite the microcrystals being oriented for single-slip deformation. Zig-zag slip was also observed in microcrystals that achieved flow stresses of ∼1300 MPa or higher. For microcrystals fabricated within interdendritic regions the flow-stress values are, on average, lower compared to dendrite core microcrystals. This difference in flow-stress is especially pronounced for microcrystals which are 5 μm in diameter. The microcrystal diameter for which bulk-like properties are estimated to be observed is approximately 350 μm, which is approaching the measured primary dendrite arm spacing for this crystal (430 μm).

  10. Ultra-thin clay layers facilitate seismic slip in carbonate faults.

    Science.gov (United States)

    Smeraglia, Luca; Billi, Andrea; Carminati, Eugenio; Cavallo, Andrea; Di Toro, Giulio; Spagnuolo, Elena; Zorzi, Federico

    2017-04-06

    Many earthquakes propagate up to the Earth's surface producing surface ruptures. Seismic slip propagation is facilitated by along-fault low dynamic frictional resistance, which is controlled by a number of physico-chemical lubrication mechanisms. In particular, rotary shear experiments conducted at seismic slip rates (1 ms -1 ) show that phyllosilicates can facilitate co-seismic slip along faults during earthquakes. This evidence is crucial for hazard assessment along oceanic subduction zones, where pelagic clays participate in seismic slip propagation. Conversely, the reason why, in continental domains, co-seismic slip along faults can propagate up to the Earth's surface is still poorly understood. We document the occurrence of micrometer-thick phyllosilicate-bearing layers along a carbonate-hosted seismogenic extensional fault in the central Apennines, Italy. Using friction experiments, we demonstrate that, at seismic slip rates (1 ms -1 ), similar calcite gouges with pre-existing phyllosilicate-bearing (clay content ≤3 wt.%) micro-layers weaken faster than calcite gouges or mixed calcite-phyllosilicate gouges. We thus propose that, within calcite gouge, ultra-low clay content (≤3 wt.%) localized along micrometer-thick layers can facilitate seismic slip propagation during earthquakes in continental domains, possibly enhancing surface displacement.

  11. Intellectual Capital.

    Science.gov (United States)

    Snyder, Herbert W.; Pierce, Jennifer Burek

    2002-01-01

    This review focuses on intellectual capital and its relationship to information professionals. Discusses asset recognition; national practices and the acceptance of intellectual capital; definitions of intellectual capital; measuring intellectual capital, including multiple and single variable measures; managing intellectual capital; and knowledge…

  12. Investigation of PDC bit failure base on stick-slip vibration analysis of drilling string system plus drill bit

    Science.gov (United States)

    Huang, Zhiqiang; Xie, Dou; Xie, Bing; Zhang, Wenlin; Zhang, Fuxiao; He, Lei

    2018-03-01

    The undesired stick-slip vibration is the main source of PDC bit failure, such as tooth fracture and tooth loss. So, the study of PDC bit failure base on stick-slip vibration analysis is crucial to prolonging the service life of PDC bit and improving ROP (rate of penetration). For this purpose, a piecewise-smooth torsional model with 4-DOF (degree of freedom) of drilling string system plus PDC bit is proposed to simulate non-impact drilling. In this model, both the friction and cutting behaviors of PDC bit are innovatively introduced. The results reveal that PDC bit is easier to fail than other drilling tools due to the severer stick-slip vibration. Moreover, reducing WOB (weight on bit) and improving driving torque can effectively mitigate the stick-slip vibration of PDC bit. Therefore, PDC bit failure can be alleviated by optimizing drilling parameters. In addition, a new 4-DOF torsional model is established to simulate torsional impact drilling and the effect of torsional impact on PDC bit's stick-slip vibration is analyzed by use of an engineering example. It can be concluded that torsional impact can mitigate stick-slip vibration, prolonging the service life of PDC bit and improving drilling efficiency, which is consistent with the field experiment results.

  13. Effect of Slip Time in Forming Neo-Esophageal Stenosis After Replacement of a Thoracic Esophagus With Nitinol Artificial Esophagus.

    Science.gov (United States)

    Liang, Xian-Liang; Liang, Jian-Hui

    2015-07-01

    Attempts have been made to investigate the effect of slip time of nitinol artificial esophagus for forming neo-esophageal stenosis after replacement of a thoracic esophagus with nitinol artificial esophagus in 20 experimental pigs. The pigs whose slip time was less than 90 days postoperatively had severe dysphagia (Bown's III) immediately after they were fed, and the dysphagia aggravated gradually later on (Bown's III-IV). The pigs whose slip time was more than 90 days postoperatively had mild/moderate dysphagia (Bown's I-II) immediately after they were fed, and the dysphagia relieved gradually later on (Bown's II-I-0). The ratios between the diameter of neo-esophagus in different slip time and normal esophagus were 25% (at 2 months postoperatively), 58% (at 4 months postoperatively), and 93% (at 6 months postoperatively), respectively. The relationship between nitinol artificial esophagus slip time and neo-esophageal stenosis showed a positive correlation. After replacement of a thoracic esophagus with nitinol artificial esophagus, the artificial esophageal slip time not only affected the original diameter of the neo-esophagus immediately, but also affected the neo-esophageal scar stricture forming process later on. The narrowing of neo-esophagus is caused by overgrowth of scar tissue. But there is the positive correlation between artificial esophagus slip time and neo-esophageal stenosis, so this can be a way of overcoming neo-esophageal stenosis by delaying slip time of artificial esophagus. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  14. 78 FR 76973 - Regulatory Capital Rules: Regulatory Capital, Implementation of Basel III, Capital Adequacy...

    Science.gov (United States)

    2013-12-20

    ... Discipline and Disclosure Requirements, Advanced Approaches Risk-Based Capital Rule, and Market Risk Capital..., 2013, a document adopting a final rule that revises its risk-based and leverage capital requirements... risk-based and leverage capital requirements for banking organizations. An allowance for additional...

  15. Intellectual Capital dan Ukuran Fundamental Kinerja Keuangan Perusahaan

    Directory of Open Access Journals (Sweden)

    Josepha C. Shanti

    2011-09-01

    Full Text Available This study aims to examine the effect of intellectual capital and the fundamental measurements of company financial performance. This study also used several control variables, namely size and type of industry. Samples used in this study is the type of company that intensively used the intellectual capital, that is the service industry. The hypothesis are tested using multiple regression. Intellectual capital in the service industry showed the influence to the company's financial performance. External size of the companies used to measure the intellectual capital is market-to-book value. Market responds to the company's profitability and company’s productivity.

  16. Using the capital markets in Ras Gas

    International Nuclear Information System (INIS)

    Voge, B.; Penzer, M.

    1997-01-01

    In December 1996, Ras Laffan Liquefied Natural Gas Company Ltd (Ras Gas) closed a multi-source financing that included an offering of US$1.2bn of bonds. The sponsors of the Ras Gas project overcame a number of obstacles on the road to closing the capital markets offering. This article provides a general overview of capital markets offerings in international project financings and discusses how Ras Gas was able to successfully integrate a capital markets offering into a financing plan which included a commercial bank facility and several export-credit agency facilities. (Author)

  17. SLIPPING MAGNETIC RECONNECTIONS WITH MULTIPLE FLARE RIBBONS DURING AN X-CLASS SOLAR FLARE

    International Nuclear Information System (INIS)

    Zheng, Ruisheng; Chen, Yao; Wang, Bing

    2016-01-01

    With the observations of the Solar Dynamics Observatory , we present the slipping magnetic reconnections with multiple flare ribbons (FRs) during an X1.2 eruptive flare on 2014 January 7. A center negative polarity was surrounded by several positive ones, and three FRs appeared. The three FRs showed apparent slipping motions, and hook structures formed at their ends. Due to the moving footpoints of the erupting structures, one tight semi-circular hook disappeared after the slippage along its inner and outer edges, and coronal dimmings formed within the hook. The east hook also faded as a result of the magnetic reconnection between the arcades of a remote filament and a hot loop that was impulsively heated by the under flare loops. Our results are accordant with the slipping magnetic reconnection regime in three-dimensional standard model for eruptive flares. We suggest that the complex structures of the flare are likely a consequence of the more complex flux distribution in the photosphere, and the eruption involves at least two magnetic reconnections.

  18. Predicting the probability of slip in gait: methodology and distribution study.

    Science.gov (United States)

    Gragg, Jared; Yang, James

    2016-01-01

    The likelihood of a slip is related to the available and required friction for a certain activity, here gait. Classical slip and fall analysis presumed that a walking surface was safe if the difference between the mean available and required friction coefficients exceeded a certain threshold. Previous research was dedicated to reformulating the classical slip and fall theory to include the stochastic variation of the available and required friction when predicting the probability of slip in gait. However, when predicting the probability of a slip, previous researchers have either ignored the variation in the required friction or assumed the available and required friction to be normally distributed. Also, there are no published results that actually give the probability of slip for various combinations of required and available frictions. This study proposes a modification to the equation for predicting the probability of slip, reducing the previous equation from a double-integral to a more convenient single-integral form. Also, a simple numerical integration technique is provided to predict the probability of slip in gait: the trapezoidal method. The effect of the random variable distributions on the probability of slip is also studied. It is shown that both the required and available friction distributions cannot automatically be assumed as being normally distributed. The proposed methods allow for any combination of distributions for the available and required friction, and numerical results are compared to analytical solutions for an error analysis. The trapezoidal method is shown to be highly accurate and efficient. The probability of slip is also shown to be sensitive to the input distributions of the required and available friction. Lastly, a critical value for the probability of slip is proposed based on the number of steps taken by an average person in a single day.

  19. Application of slip-band visualization technique to tensile analysis of laser-welded aluminum alloy

    Science.gov (United States)

    Muchiar, -; Yoshida, Sanichiro J.; Widiastuti, Rini; Kusnowo, A.; Takahashi, Kunimitsu; Sato, Shunichi

    1997-03-01

    Recently we have developed a new optical interferometric technique capable of visualizing slip band occurring in a deforming solid-state object. In this work we applied this technique to a tensile analysis of laser-welded aluminum plate samples, and successfully revealed stress concentration that shows strong relationships with the tensile strength and the fracture mechanism. We believe that this method is a new, convenient way to analyze the deformation characteristics of welded objects and evaluate the quality of welding. The analysis has been made for several types of aluminum alloys under various welding conditions, and has shown the following general results. When the penetration is deep, a slip band starts appearing at the fusion zone in an early stage of the elastic region of the strain-stress curve and stays there till the sample fractures at that point. When the penetration is shallow, a slip band appears only after the yield point and moves vigorously over the whole surface of the sample till a late stage of plastic deformation when the slip band stays at the fusion zone where the sample eventually fractures. When the penetration depth is medium, some intermediate situation of the above two extreme cases is observed.

  20. Great earthquakes and slow slip events along the Sagami trough and outline of the Kanto Asperity Project

    Science.gov (United States)

    Kobayashi, R.; Yamamoto, Y.; Sato, T.; Shishikura, M.; Ito, H.; Shinohara, M.; Kawamura, K.; Shibazaki, B.

    2010-12-01

    The Kanto region is one of the most densely populated urban areas in the world. Complicated plate configurations are due to T-T-T type triple junction, island arc-island arc collision zone, and very shallow angle between axis of the Sagami trough and subducting direction. Great earthquakes along the Sagami trough have repeatedly occurred. The 1703 Genroku and 1923 (Taisho) Kanto earthquakes caused severe damages in the Tokyo metropolitan area. Intriguingly slow slip events have also repeatedly occurred in an area adjacent to the asperities of the great earthquakes, off Boso peninsula (e.g., Ozawa et al 2007). In the cases of the Nankai and Cascadia subduction zones, slow slip events occur at deeper levels than the asperity, in a transition zone between the asperity and a region of steady slip. In contrast, slow slip events in the Kanto region have occurred at relatively shallow depths, at the same level as the asperity, raising the possibility of friction controlled by different conditions to those (temperature and pressure) encountered at Nankai and Cascadia. We focus on three different types of seismic events occurring repeatedly at the almost same depth of the seismogenic zone along the Sagami trough (5-20 km) (1) The 1923 M~7.9 Taisho earthquake, located in Sagami Bay. Maximum slip is about 6 m, the recurrence interval is 200-400 yr, and the coupling rate is 80-100% (“coupling rates” = “slip amounts during earthquakes or slow-slip events” / [“rate of motion of the Philippine Sea Plate” - “recurrence interval”]) . (2) The 1703 M~8.2 Genroku earthquake, located in Sagami Bay, but also extending to the southern part of Boso Peninsula. Maximum slip is 15-20 m, the recurrence interval is ~2000 yr, and the coupling rate at the southern part of the Boso Peninsula is 10-30%. (3) Boso slow-slip events, located southeast of Boso Peninsula. Maximum slip is 15-20 cm over ~10 days, the recurrence interval is 5-6 yr, and the coupling rate is 70

  1. Using real-estate-based financing to access capital.

    Science.gov (United States)

    Tobin, W C; Kryzaniak, L A

    1998-07-01

    One strategy employed by healthcare organizations to increase their market presence is the construction of new facilities. Accessing capital to fund such construction, however, has become more of a challenge. One relatively untapped source of building capital is real-estate-based financing. Nonrecourse mortgages, turnkey net leases, and synthetic leases can provide several advantages to healthcare organizations seeking capital, assuming issues related to building ownership, debt and balance sheet effects, and tax-exempt status have been thoroughly explored first.

  2. Slow Slip and Earthquake Nucleation in Meter-Scale Laboratory Experiments

    Science.gov (United States)

    Mclaskey, G.

    2017-12-01

    The initiation of dynamic rupture is thought to be preceded by a quasistatic nucleation phase. Observations of recent earthquakes sometimes support this by illuminating slow slip and foreshocks in the vicinity of the eventual hypocenter. I describe laboratory earthquake experiments conducted on two large-scale loading machines at Cornell University that provide insight into the way earthquake nucleation varies with normal stress, healing time, and loading rate. The larger of the two machines accommodates a 3 m long granite sample, and when loaded to 7 MPa stress levels, we observe dynamic rupture events that are preceded by a measureable nucleation zone with dimensions on the order of 1 m. The smaller machine accommodates a 0.76 m sample that is roughly the same size as the nucleation zone. On this machine, small variations in nucleation properties result in measurable differences in slip events, and we generate both dynamic rupture events (> 0.1 m/s slip rates) and slow slip events ( 0.001 to 30 mm/s slip rates). Slow events occur when instability cannot fully nucleate before reaching the sample ends. Dynamic events occur after long healing times or abrupt increases in loading rate which suggests that these factors shrink the spatial and temporal extents of the nucleation zone. Arrays of slip, strain, and ground motion sensors installed on the sample allow us to quantify seismic coupling and study details of premonitory slip and afterslip. The slow slip events we observe are primarily aseismic (less than 1% of the seismic coupling of faster events) and produce swarms of very small M -6 to M -8 events. These mechanical and seismic interactions suggest that faults with transitional behavior—where creep, small earthquakes, and tremor are often observed—could become seismically coupled if loaded rapidly, either by a slow slip front or dynamic rupture of an earthquake that nucleated elsewhere.

  3. Perception of slipperiness and prospective risk of slipping at work

    Science.gov (United States)

    Courtney, Theodore K; Verma, Santosh K; Chang, Wen-Ruey; Huang, Yueng-Hsiang; Lombardi, David A; Brennan, Melanye J; Perry, Melissa J

    2013-01-01

    Objectives Falls are a leading cause of injury at work, and slipping is the predominant cause of falling. Prior research has suggested a modest correlation between objective measures (such as coefficient of friction, COF) and subjective measures of slipperiness (such as worker perceptions) in the workplace. However, the degree of association between subjective measures and the actual risk of slipping at the workplace is unknown. This study examined the association between perception of slipperiness and the risk of slipping. Methods 475 workers from 36 limited-service restaurants participated in a 12-week prospective cohort study. At baseline, demographic information was collected, participants rated floor slipperiness in eight areas of the restaurant, and work environment factors, such as COF, were measured. Restaurant-level and area-level mean perceptions of slipperiness were calculated. Participants then reported their slip experience at work on a weekly basis for the next 12 weeks. The associations between perception of slipperiness and the rate of slipping were assessed. Results Adjusting for age, gender, body mass index, education, primary language, mean COF, use of slip-resistant shoes, and restaurant chain, each 1-point increase in mean restaurant-level perception of slipperiness (4-point scale) was associated with a 2.71 times increase in the rate of slipping (95% CI 1.25 to 5.87). Results were similar for area-level perception within the restaurant (rate ratios (RR) 2.92, 95% CI 2.41 to 3.54). Conclusions Perceptions of slipperiness and the subsequent rate of slipping were strongly associated. These findings suggest that safety professionals, risk managers and employers could use aggregated worker perceptions of slipperiness to identify slipping hazards and, potentially, to assess intervention effectiveness. PMID:22935953

  4. Variations in strength and slip rate along the san andreas fault system.

    Science.gov (United States)

    Jones, C H; Wesnousky, S G

    1992-04-03

    Convergence across the San Andreas fault (SAF) system is partitioned between strike-slip motion on the vertical SAF and oblique-slip motion on parallel dip-slip faults, as illustrated by the recent magnitude M(s) = 6.0 Palm Springs, M(s) = 6.7 Coalinga, and M(s) = 7.1 Loma Prieta earthquakes. If the partitioning of slip minimizes the work done against friction, the direction of slip during these recent earthquakes depends primarily on fault dip and indicates that the normal stress coefficient and frictional coefficient (micro) vary among the faults. Additionally, accounting for the active dip-slip faults reduces estimates of fault slip rates along the vertical trace of the SAF by about 50 percent in the Loma Prieta and 100 percent in the North Palm Springs segments.

  5. Fault slip and earthquake recurrence along strike-slip faults — Contributions of high-resolution geomorphic data

    KAUST Repository

    Zielke, Olaf

    2015-01-01

    Understanding earthquake (EQ) recurrence relies on information about the timing and size of past EQ ruptures along a given fault. Knowledge of a fault\\'s rupture history provides valuable information on its potential future behavior, enabling seismic hazard estimates and loss mitigation. Stratigraphic and geomorphic evidence of faulting is used to constrain the recurrence of surface rupturing EQs. Analysis of the latter data sets culminated during the mid-1980s in the formulation of now classical EQ recurrence models, now routinely used to assess seismic hazard. Within the last decade, Light Detection and Ranging (lidar) surveying technology and other high-resolution data sets became increasingly available to tectono-geomorphic studies, promising to contribute to better-informed models of EQ recurrence and slip-accumulation patterns. After reviewing motivation and background, we outline requirements to successfully reconstruct a fault\\'s offset accumulation pattern from geomorphic evidence. We address sources of uncertainty affecting offset measurement and advocate approaches to minimize them. A number of recent studies focus on single-EQ slip distributions and along-fault slip accumulation patterns. We put them in context with paleoseismic studies along the respective faults by comparing coefficients of variation CV for EQ inter-event time and slip-per-event and find that a) single-event offsets vary over a wide range of length-scales and the sources for offset variability differ with length-scale, b) at fault-segment length-scales, single-event offsets are essentially constant, c) along-fault offset accumulation as resolved in the geomorphic record is dominated by essentially same-size, large offset increments, and d) there is generally no one-to-one correlation between the offset accumulation pattern constrained in the geomorphic record and EQ occurrence as identified in the stratigraphic record, revealing the higher resolution and preservation potential of

  6. Experiments on vibration-driven stick-slip locomotion: A sliding bifurcation perspective

    Science.gov (United States)

    Du, Zhouwei; Fang, Hongbin; Zhan, Xiong; Xu, Jian

    2018-05-01

    Dry friction appears at the contact interface between two surfaces and is the source of stick-slip vibrations. Instead of being a negative factor, dry friction is essential for vibration-driven locomotion system to take effect. However, the dry-friction-induced stick-slip locomotion has not been fully understood in previous research, especially in terms of experiments. In this paper, we experimentally study the stick-slip dynamics of a vibration-driven locomotion system from a sliding bifurcation perspective. To this end, we first design and build a vibration-driven locomotion prototype based on an internal piezoelectric cantilever. By utilizing the mechanical resonance, the small piezoelectric deformation is significantly amplified to drive the prototype to achieve effective locomotion. Through identifying the stick-slip characteristics in velocity histories, we could categorize the system's locomotion into four types and obtain a stick-slip categorization diagram. In each zone of the diagram the locomotion exhibits qualitatively different stick-slip dynamics. Such categorization diagram is actually a sliding bifurcation diagram; crossing from one stick-slip zone to another corresponds to the triggering of a sliding bifurcation. In addition, a simplified single degree-of-freedom model is established, with the rationality of simplification been explained theoretically and numerically. Based on the equivalent model, a numerical stick-slip categorization is also obtained, which shows good agreement with the experiments both qualitatively and quantitatively. To the best of our knowledge, this is the first work that experimentally generates a sliding bifurcation diagram. The obtained stick-slip categorizations deepen our understanding of stick-slip dynamics in vibration-driven systems and could serve as a base for system design and optimization.

  7. An Improved Optimal Slip Ratio Prediction considering Tyre Inflation Pressure Changes

    Directory of Open Access Journals (Sweden)

    Guoxing Li

    2015-01-01

    Full Text Available The prediction of optimal slip ratio is crucial to vehicle control systems. Many studies have verified there is a definitive impact of tyre pressure change on the optimal slip ratio. However, the existing method of optimal slip ratio prediction has not taken into account the influence of tyre pressure changes. By introducing a second-order factor, an improved optimal slip ratio prediction considering tyre inflation pressure is proposed in this paper. In order to verify and evaluate the performance of the improved prediction, a cosimulation platform is developed by using MATLAB/Simulink and CarSim software packages, achieving a comprehensive simulation study of vehicle braking performance cooperated with an ABS controller. The simulation results show that the braking distances and braking time under different tyre pressures and initial braking speeds are effectively shortened with the improved prediction of optimal slip ratio. When the tyre pressure is slightly lower than the nominal pressure, the difference of braking performances between original optimal slip ratio and improved optimal slip ratio is the most obvious.

  8. Hydrodynamic slip length as a surface property

    Science.gov (United States)

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.

    2016-02-01

    Equilibrium and nonequilibrium molecular dynamics simulations were conducted in order to evaluate the hypothesis that the hydrodynamic slip length is a surface property. The system under investigation was water confined between two graphite layers to form nanochannels of different sizes (3-8 nm). The water-carbon interaction potential was calibrated by matching wettability experiments of graphitic-carbon surfaces free of airborne hydrocarbon contamination. Three equilibrium theories were used to calculate the hydrodynamic slip length. It was found that one of the recently reported equilibrium theories for the calculation of the slip length featured confinement effects, while the others resulted in calculations significantly hindered by the large margin of error observed between independent simulations. The hydrodynamic slip length was found to be channel-size independent using equilibrium calculations, i.e., suggesting a consistency with the definition of a surface property, for 5-nm channels and larger. The analysis of the individual trajectories of liquid particles revealed that the reason for observing confinement effects in 3-nm nanochannels is the high mobility of the bulk particles. Nonequilibrium calculations were not consistently affected by size but by noisiness in the smallest systems.

  9. Volatility of Capital Flows to Emerging Economies

    Directory of Open Access Journals (Sweden)

    Katia Rocha

    2013-09-01

    Full Text Available The paper proposes a panel model to the determinants of capital flow volatility to a group of 18 emerging market economies (EME in the period of 2000 to 2011. It studies the robustness of the model regarding different volatility measures; analyses several types of gross capital inflow; focusing the role of government institutional quality and the development of domestic financial system (banks, insurance companies, and capital markets – stocks, bonds and derivatives. The EME analyzed represented roughly 95% of the Emerging Markets Bond Index Global – EMBIG in January 2013, being the biggest destination to international capital flow to EME according to the report of the Bank for International Settlements - BIS (2009. The main conclusion suggests that a reduction of capital flow volatility can be achieved by the adoption of policies that improve government institutional quality and promote development, stability and efficiency of the domestic financial system.

  10. provider venture capital funds: investing in innovation.

    Science.gov (United States)

    Potter, Mary Jo; Wesslund, Rick

    2016-05-01

    As health systems continue to embrace disruptive innovation, they are increasingly likely to consider making a move into venture capital. Working in venture capital can benefit a health system in several ways, including: Allowing it to operate outside of bureaucracy and align projects with its core values. Encouraging innovation within the organization. Enabling it to respond quickly to changes in the market.

  11. Perceived risks for slipping and falling at work during wintertime and criteria for a slip-resistant winter shoe among Swedish outdoor workers

    OpenAIRE

    Norlander, Anna; Miller, Michael; Gard, Gunvor

    2015-01-01

    The leading cause of work related accidents in Sweden is falls. Many slips and falls occur on icy and snowy surfaces, but there is limited knowledge about how to prevent accidents during outdoor work in winter conditions. The purpose of this study was to describe risk factors of slips and falls and criteria for slip-resistant winter shoes from a user perspective. The result is based on focus group interviews with 20 men and women working in mail delivery, construction and home care in Sweden....

  12. Prediction of fluid velocity slip at solid surfaces

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt; Todd, Billy; Daivis, Peter

    2011-01-01

    methods, it allows us to directly compute the intrinsic wall-fluid friction coefficient rather than an empirical friction coefficient that includes all sources of friction for planar shear flow. The slip length predicted by our method is in excellent agreement with the slip length obtained from direct...

  13. Wheel slip dump valve for railway braking system

    Science.gov (United States)

    Zhang, Xuan; Zhang, LiHao; Li, QingXuan; Shi, YanTao

    2017-09-01

    As we all know, pneumatic braking system plays an important role in the safety of the whole vehicle. In the anti slip braking system, the pressure of braking cylinder can be adjusted by the quick power response of wheel slip dump valve, so that the lock situation won’t occur during vehicle service. During the braking of railway vehicles, the braking force provided by braking disc reduces vehicle’s speed. But the locking slip will happen due to the oversize of braking force or the reduction of sticking coefficient between wheel and rail. It will cause not only the decline of braking performance but also the increase of braking distance. In the meanwhile, it will scratch the wheel and influence the stable running of vehicles. Now, the speed of passenger vehicle has been increased. In order to shorten the braking distance as far as possible, sticking stickiness must be fully applied. So the occurrence probability of wheel slip is increased.

  14. Velocity-dependent quantum phase slips in 1D atomic superfluids.

    Science.gov (United States)

    Tanzi, Luca; Scaffidi Abbate, Simona; Cataldini, Federica; Gori, Lorenzo; Lucioni, Eleonora; Inguscio, Massimo; Modugno, Giovanni; D'Errico, Chiara

    2016-05-18

    Quantum phase slips are the primary excitations in one-dimensional superfluids and superconductors at low temperatures but their existence in ultracold quantum gases has not been demonstrated yet. We now study experimentally the nucleation rate of phase slips in one-dimensional superfluids realized with ultracold quantum gases, flowing along a periodic potential. We observe a crossover between a regime of temperature-dependent dissipation at small velocity and interaction and a second regime of velocity-dependent dissipation at larger velocity and interaction. This behavior is consistent with the predicted crossover from thermally-assisted quantum phase slips to purely quantum phase slips.

  15. Relating stick-slip friction experiments to earthquake source parameters

    Science.gov (United States)

    McGarr, Arthur F.

    2012-01-01

    Analytical results for parameters, such as static stress drop, for stick-slip friction experiments, with arbitrary input parameters, can be determined by solving an energy-balance equation. These results can then be related to a given earthquake based on its seismic moment and the maximum slip within its rupture zone, assuming that the rupture process entails the same physics as stick-slip friction. This analysis yields overshoots and ratios of apparent stress to static stress drop of about 0.25. The inferred earthquake source parameters static stress drop, apparent stress, slip rate, and radiated energy are robust inasmuch as they are largely independent of the experimental parameters used in their estimation. Instead, these earthquake parameters depend on C, the ratio of maximum slip to the cube root of the seismic moment. C is controlled by the normal stress applied to the rupture plane and the difference between the static and dynamic coefficients of friction. Estimating yield stress and seismic efficiency using the same procedure is only possible when the actual static and dynamic coefficients of friction are known within the earthquake rupture zone.

  16. Origin and structure of major orogen-scale exhumed strike-slip

    Science.gov (United States)

    Cao, Shuyun; Neubauer, Franz

    2016-04-01

    The formation of major exhumed strike-slip faults represents one of the most important dynamic processes affecting the evolution of the Earth's lithosphere and surface. Detailed models of the potential initiation and properties and architecture of orogen-scale exhumed strike-slip faults and how these relate to exhumation are rare. In this study, we deal with key properties controlling the development of major exhumed strike-slip fault systems, which are equivalent to the deep crustal sections of active across fault zones. We also propose two dominant processes for the initiation of orogen-scale exhumed strike-slip faults: (1) pluton-controlled and (2) metamorphic core complex-controlled strike-slip faults. In these tectonic settings, the initiation of faults occurs by rheological weakening along hot-to-cool contacts and guides the overall displacement and ultimate exhumation. These processes result in a specific thermal and structural architecture of such faults. These types of strike-slip dominated fault zones are often subparallel to mountain ranges and expose a wide variety of mylonitic, cataclastic and non-cohesive fault rocks, which were formed at different structural levels of the crust during various stages of faulting. The high variety of distinctive fault rocks is a potential evidence for recognition of these types of strike-slip faults. Exhumation of mylonitic rocks is, therefore, a common feature of such reverse oblique-slip strike-slip faults, implying major transtensive and/or transpressive processes accompanying pure strike-slip motion during exhumation. Some orogen-scale strike-slip faults nucleate and initiate along rheologically weak zones, e.g. at granite intrusions, zones of low-strength minerals, thermally weakened crust due to ascending fluids, and lateral borders of hot metamorphic core complexes. A further mechanism is the juxtaposition of mechanically strong mantle lithosphere to hot asthenosphere in continental transform faults (e.g., San

  17. A multilevel simulation approach to derive the slip boundary condition of the solid phase in two-fluid models

    Science.gov (United States)

    Feng, Zhi-Gang; Michaelides, Efstathios; Mao, Shaolin

    2011-11-01

    The simulation of particulate flows for industrial applications often requires the use of a two-fluid model (TFM), where the solid particles are considered as a separate continuous phase. One of the underlining uncertainties in the use of aTFM in multiphase computations comes from the boundary condition of the solid phase. The no-slip condition at a solid boundary is not a valid assumption for the solid phase. Instead, several researchers advocate a slip condition as a more appropriate boundary condition. However, the question on the selection of an exact slip length or a slip velocity coefficient is still unanswered. In the present work we propose a multilevel simulation approach to compute the slip length that is applicable to a TFM. We investigate the motion of a number of particles near a vertical solid wall, while the particles are in fluidization using a direct numerical simulation (DNS); the positions and velocities of the particles are being tracked and analyzed at each time step. It is found that the time- and vertical-space averaged values of the particle velocities converge, yielding velocity profiles that can be used to deduce the particle slip length close to a solid wall. This work was supported by a grant from the DOE-NETL (DE-NT0008064) and by a grant from NSF (HRD-0932339).

  18. Understanding operational risk capital approximations: First and second orders

    Directory of Open Access Journals (Sweden)

    Gareth W. Peters

    2013-07-01

    Full Text Available We set the context for capital approximation within the framework of the Basel II / III regulatory capital accords. This is particularly topical as the Basel III accord is shortly due to take effect. In this regard, we provide a summary of the role of capital adequacy in the new accord, highlighting along the way the significant loss events that have been attributed to the Operational Risk class that was introduced in the Basel II and III accords. Then we provide a semi-tutorial discussion on the modelling aspects of capital estimation under a Loss Distributional Approach (LDA. Our emphasis is to focuss on the important loss processes with regard to those that contribute most to capital, the so called “high consequence, low frequency" loss processes. This leads us to provide a tutorial overview of heavy tailed loss process modelling in OpRisk under Basel III, with discussion on the implications of such tail assumptions for the severity model in an LDA structure. This provides practitioners with a clear understanding of the features that they may wish to consider when developing OpRisk severity models in practice. From this discussion on heavy tailed severity models, we then develop an understanding of the impact such models have on the right tail asymptotics of the compound loss process and we provide detailed presentation of what are known as first and second order tail approximations for the resulting heavy tailed loss process. From this we develop a tutorial on three key families of risk measures and their equivalent second order asymptotic approximations: Value-at-Risk (Basel III industry standard; Expected Shortfall (ES and the Spectral Risk Measure. These then form the capital approximations. We then provide a few example case studies to illustrate the accuracy of these asymptotic captial approximations, the rate of the convergence of the assymptotic result as a function of the LDA frequency and severity model parameters, the sensitivity

  19. Questions of trust in health research on social capital: what aspects of personal network social capital do they measure?

    Science.gov (United States)

    Carpiano, Richard M; Fitterer, Lisa M

    2014-09-01

    Health research on personal social capital has often utilized measures of respondents' perceived trust of others as either a proxy for one's social capital in the absence of more focused measures or as a subjective component of social capital. Little empirical work has evaluated the validity of such practices. We test the construct validity of two trust measures used commonly in health research on social capital-generalized trust and trust of neighbors-with respect to measures of people's general network-, organization-, family-, friend-, and neighborhood-based social capital and the extent to which these two trust measures are associated with self-rated general health and mental health when social capital measures are included in the same models. Analyses of 2008 Canadian General Social Survey data (response rate 57.3%) indicate that generalized trust and trust of neighbors are both positively-yet modestly-associated with measures of several domains of network-based social capital. Both trust measures are positively associated with general and mental health, but these associations remain robust after adjusting for social capital measures. Our findings suggest that (a) trust is conceptually distinct from social capital, (b) trust measures are inadequate proxies for actual personal social networks, and (c) trust measures may only be capturing psychological aspects relevant to-but not indicative of-social capital. Though links between perceived trust and health deserve study, health research on social capital needs to utilize measures of respondents' actual social networks and their inherent resources. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. THE EFFECT OF HUMAN CAPITAL ON SOCIAL CAPITAL AMONG ENTREPRENEURS

    OpenAIRE

    HANNES OTTÓSSON; KIM KLYVER

    2010-01-01

    Using data collected from 714 entrepreneurs in a random sample of 10,000 Danes, this study provides an investigation of the effect of human capital on social capital among entrepreneurs. Previous entrepreneurship research has extensively investigated the separated effect of human capital and social capital on different entrepreneurial outputs. The study takes a step back and investigates how these two capital concepts are related — specifically how human capital influences social capital. In ...

  1. Impact of anisotropic slip on transient three dimensional MHD flow of ferrofluid over an inclined radiate stretching surface

    Directory of Open Access Journals (Sweden)

    A.M. Rashad

    2017-04-01

    Full Text Available The present study explores the impact of anistropic slip on transient three dimensional MHD flow of Cobalt-kerosene ferrofluid over an inclined radiate stretching surface. The governing partial differential equations for this study are solved by the Thomas algorithm with finite-difference type. The impacts of several significant parameters on flow and heat transfer characteristics are exhibited graphically. The conclusion is revealed that the local Nusselt number is significantly promoted due to influence of thermal radiation whereas diminished with elevating the solid volume fraction, magnet parameter and slip factors. Further, the skin friction coefficients visualizes a considerable enhancement with boosting the magnet and radiation parameters, but a prominent reduction is recorded by elevating the solid volume fraction and slip factors.

  2. Slipping slender bodies and enhanced flagellar locomotion

    Science.gov (United States)

    Man, Yi; Lauga, Eric

    2017-11-01

    In the biological world, many cells exploit slender appendages to swim, include numerous species of bacteria, algae and spermatozoa. A classical method to describe the flow field around such appendages is slender-body theory (SBT), which is often used to study flagellar motility in Newtonian fluids. However, biology environments are often rheologically complex due to the presence of polymers. These polymers generically phase-separate near rigid boundaries where low-viscosity fluid layers lead to effective slip on the surface. In this talk, we present an analytical derivation of SBT in the case where the no-slip boundary condition on the appendage is replaced by a Navier slip boundary condition. Our results demonstrate in particular a systematic reduction of the resistance coefficient of the slender filaments in their tangential direction, which leads to enhanced flagellar locomotion.

  3. Green Capital: Student Capital student-led evaluation

    OpenAIRE

    Runkle, Q.; Haines, T.; Piper, K.; Leach, S.

    2016-01-01

    To assess and evaluate the impact of the Green Capital: Student Capital project, the partnership (the University of the West of England, the University of Bristol, the Students’ Union at UWE, and Bristol Students’ Union) worked with NUS to train a team of students from both universities to lead an evaluation process. There were two key aims for the evaluation: \\ud \\ud • To verify the quantitative outputs of the Green Capital: Student Capital project; \\ud • And to make a qualitative assessment...

  4. Assessment of slip factor models at off-design condition

    International Nuclear Information System (INIS)

    Yoon, Sung Ho; Baek, Je Hyun

    2000-01-01

    Slip factor is defined as an empirical factor being multiplied to theoretical energy transfer for the estimation of real work input of a centrifugal compressor. Researchers have tried to develop a simple empirical model, for a century, to predict a slip factor. However most these models were developed on the condition of design point assuming inviscid flow. So these models often fail to predict a correct slip factor at off-design condition. In this study, we summarized various slip factor models and compared these models with experimental and numerical data at off-design condition. As a result of this study, Wiesner's and Paeng and Chung's models are applicable for radial impeller, but all the models are not suitable for backswept impeller. Finally, the essential avenues for future study is discussed

  5. Estimation of slip scenarios of mega-thrust earthquakes and strong motion simulations for Central Andes, Peru

    Science.gov (United States)

    Pulido, N.; Tavera, H.; Aguilar, Z.; Chlieh, M.; Calderon, D.; Sekiguchi, T.; Nakai, S.; Yamazaki, F.

    2012-12-01

    We have developed a methodology for the estimation of slip scenarios for megathrust earthquakes based on a model of interseismic coupling (ISC) distribution in subduction margins obtained from geodetic data, as well as information of recurrence of historical earthquakes. This geodetic slip model (GSM) delineates the long wavelength asperities within the megathrust. For the simulation of strong ground motion it becomes necessary to introduce short wavelength heterogeneities to the source slip to be able to efficiently simulate high frequency ground motions. To achieve this purpose we elaborate "broadband" source models constructed by combining the GSM with several short wavelength slip distributions obtained from a Von Karman PSD function with random phases. Our application of the method to Central Andes in Peru, show that this region has presently the potential of generating an earthquake with moment magnitude of 8.9, with a peak slip of 17 m and a source area of approximately 500 km along strike and 165 km along dip. For the strong motion simulations we constructed 12 broadband slip models, and consider 9 possible hypocenter locations for each model. We performed strong motion simulations for the whole central Andes region (Peru), spanning an area from the Nazca ridge (16^o S) to the Mendana fracture (9^o S). For this purpose we use the hybrid strong motion simulation method of Pulido et al. (2004), improved to handle a general slip distribution. Our simulated PGA and PGV distributions indicate that a region of at least 500 km along the coast of central Andes is subjected to a MMI intensity of approximately 8, for the slip model that yielded the largest ground motions among the 12 slip models considered, averaged for all assumed hypocenter locations. This result is in agreement with the macroseismic intensity distribution estimated for the great 1746 earthquake (M~9) in central Andes (Dorbath et al. 1990). Our results indicate that the simulated PGA and PGV for

  6. Triads of capital

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase

    of capital means a coherent stock of capital, including social, cultural and physical capital, which belongs to a local community. The case of civic organization in rural Denmark 1800-1900 shows how the three capitals successively acted as driving forces: physical capital about year 1800, social capital...... about year 1880, and cultural capital about year 1900. In each case, one form of capital changed the two others in a chain reaction process, which ultimately led to a major reorganization of the triads of capital in the local rural communities....

  7. Listening in on Friction: Stick-Slip Acoustical Signatures in Velcro

    Science.gov (United States)

    Hurtado Parra, Sebastian; Morrow, Leslie; Radziwanowski, Miles; Angiolillo, Paul

    2013-03-01

    The onset of kinetic friction and the possible resulting stick-slip motion remain mysterious phenomena. Moreover, stick-slip dynamics are typically accompanied by acoustic bursts that occur temporally with the slip event. The dry sliding dynamics of the hook-and-loop system, as exemplified by Velcro, manifest stick-slip behavior along with audible bursts that are easily micrphonically collected. Synchronized measurements of the friction force and acoustic emissions were collected as hooked Velcro was driven at constant velocity over a bed of looped Velcro in an anechoic chamber. Not surprising, the envelope of the acoustic bursts maps well onto the slip events of the friction force time series and the intensity of the bursts trends with the magnitude of the difference of the friction force during a stick-slip event. However, the analysis of the acoustic emission can serve as a sensitive tool for revealing some of the hidden details of the evolution of the transition from static to kinetic friction. For instance, small acoustic bursts are seen prior to the Amontons-Coulomb threshold, signaling precursor events prior to the onset of macroscopically observed motion. Preliminary spectral analysis of the acoustic emissions including intensity-frequency data will be presented.

  8. Dislocation cross-slip in fcc solid solution alloys

    International Nuclear Information System (INIS)

    Nöhring, Wolfram Georg; Curtin, W.A.

    2017-01-01

    Cross-slip is a fundamental process of screw dislocation motion and plays an important role in the evolution of work hardening and dislocation structuring in metals. Cross-slip has been widely studied in pure FCC metals but rarely in FCC solid solutions. Here, the cross-slip transition path in solid solutions is calculated using atomistic methods for three representative systems of Ni-Al, Cu-Ni and Al-Mg over a range of solute concentrations. Studies using both true random alloys and their corresponding average-alloy counterparts allow for the independent assessment of the roles of (i) fluctuations in the spatial solute distribution in the true random alloy randomness and (ii) average alloy properties such as stacking fault energy. The results show that the solute fluctuations dominate the activation energy barrier, i.e. there are large sample-to-sample variations around the average activation barrier. The variations in activation barrier correlate linearly with the energy difference between the initial and final states. The distribution of this energy difference can be computed analytically in terms of the solute/dislocation interaction energies. Thus, the distribution of cross-slip activation energies can be accurately determined from a parameter-free analytic model. The implications of the statistical distribution of activation energies on the rate of cross-slip in real alloys are then identified.

  9. Bourdieu's Cultural Capital in Relation to Food Choices: A Systematic Review of Cultural Capital Indicators and an Empirical Proof of Concept.

    Directory of Open Access Journals (Sweden)

    Carlijn B M Kamphuis

    Full Text Available Unhealthy food choices follow a socioeconomic gradient that may partly be explained by one's 'cultural capital', as defined by Bourdieu. We aim 1 to carry out a systematic review to identify existing quantitative measures of cultural capital, 2 to develop a questionnaire to measure cultural capital for food choices, and 3 to empirically test associations of socioeconomic position with cultural capital and food choices, and of cultural capital with food choices.We systematically searched large databases for the key-word 'cultural capital' in title or abstract. Indicators of objectivised cultural capital and family institutionalised cultural capital, as identified by the review, were translated to food choice relevant indicators. For incorporated cultural capital, we used existing questionnaires that measured the concepts underlying the variety of indicators as identified by the review, i.e. participation, skills, knowledge, values. The questionnaire was empirically tested in a postal survey completed by 2,953 adults participating in the GLOBE cohort study, The Netherlands, in 2011.The review yielded 113 studies that fulfilled our inclusion criteria. Several indicators of family institutionalised (e.g. parents' education completed and objectivised cultural capital (e.g. possession of books, art were consistently used. Incorporated cultural capital was measured with a large variety of indicators (e.g. cultural participation, skills. Based on this, we developed a questionnaire to measure cultural capital in relation to food choices. An empirical test of the questionnaire showed acceptable overall internal consistency (Cronbach's alpha of .654; 56 items, and positive associations between socioeconomic position and cultural capital, and between cultural capital and healthy food choices.Cultural capital may be a promising determinant for (socioeconomic inequalities in food choices.

  10. Intellectual Capital

    DEFF Research Database (Denmark)

    Bukh, Per Nikolaj; Christensen, Karina Skovvang

    2015-01-01

    Intellectual capital (IC) consists of human capital, organizational capital, and relational capital, and their relationships. It has been said to be important to explain the difference between market value and book value of a firm, but measurement of IC is more likely to be important because...

  11. A disciplined approach to capital: today's healthcare imperative.

    Science.gov (United States)

    Dupuis, Patrick J; Kaufman, Kenneth

    2007-07-01

    BJC HealthCare's experience exemplifies several basic principles of a finance-based approach to capital. Organizations that adopt this approach look to improve processes first, remove costs second, and spend capital last. Multiyear planning is required to quantitatively identify the profitability and liquidity requirements of strategic initiatives and address essential funding and financing issues.

  12. The cenozoic strike-slip faults and TTHE regional crust stability of Beishan area

    International Nuclear Information System (INIS)

    Guo Zhaojie; Zhang Zhicheng; Zhang Chen; Liu Chang; Zhang Yu; Wang Ju; Chen Weiming

    2008-01-01

    The remote sensing images and geological features of Beishan area indicate that the Altyn Tagh fault, Sanweishan-Shuangta fault, Daquan fault and Hongliuhe fault are distributed in Beishan area from south to north. The faults are all left-lateral strike-slip faults with trending of NE40-50°, displaying similar distribution pattern. The secondary branch faults are developed at the end of each main strike-slip fault with nearly east to west trending form dendritic oblique crossings at the angle of 30-50°. Because of the left-lateral slip of the branch faults, the granites or the blocks exposed within the branch faults rotate clockwisely, forming 'Domino' structures. So the structural style of Beishan area consists of the Altyn Tagh fault, Sanweishan-Shuangta fault, Daquan fault, Hongliuhe fault and their branch faults and rotational structures between different faults. Sedimentary analysis on the fault valleys in the study area and ESR chronological test of fault clay exhibit that the Sanweishan-Shuangta fault form in the late Pliocene (N2), while the Daquan fault displays formation age of l.5-1.2 Ma, and the activity age of the relevant branch faults is Late Pleistocene (400 ka). The ages become younger from the Altyn Tagh fault to the Daquan fault and strike-slip faults display NW trending extension, further revealing the lateral growth process of the strike-slip boundary at the northern margin during the Cenozoic uplift of Tibetan Plateau. The displacement amounts on several secondary faults caused by the activities of the faults are slight due to the above-mentioned structural distribution characteristics of Beishan area, which means that this area is the most stable active area with few seismic activities. We propose the main granitic bodies in Beishan area could be favorable preselected locations for China's high level radioactive waste repository. (authors)

  13. Capital financing in prospective payment.

    Science.gov (United States)

    Oszustowicz, R J; Dreachslin, J L

    1984-03-01

    In the era of prospective payment, arranging financing for hospital capital projects is expected to become even more complicated than under cost-based reimbursement systems. This article outlines the information needed for a bond issue in the prospective payment environment, defines the roles and duties of several external persons and organizations involved with planning a major capital financing, and provides an overview of the entire process. This article assumes for illustrative purposes that a tax-exempt bond issue is going to be used to finance a facility expansion. This method was chosen since over 70% of all major capital financing for hospitals use the tax-exempt bond as the principal vehicle for attracting the necessary debt to finance a major construction project. The tax-exempt bond issue also requires the most detail in documentation and legal provisions.

  14. 12 CFR 1229.5 - Capital distributions for adequately capitalized Banks.

    Science.gov (United States)

    2010-01-01

    ... capitalized Banks. 1229.5 Section 1229.5 Banks and Banking FEDERAL HOUSING FINANCE AGENCY ENTITY REGULATIONS CAPITAL CLASSIFICATIONS AND PROMPT CORRECTIVE ACTION Federal Home Loan Banks § 1229.5 Capital... classification of adequately capitalized. A Bank may not make a capital distribution if such distribution would...

  15. Existence of Stick-Slip Periodic Solutions in a Dry Friction Oscillator

    International Nuclear Information System (INIS)

    Li Qun-Hong; Chen Yu-Ming; Qin Zhi-Ying

    2011-01-01

    The stick-slip behavior in friction oscillators is very complicated due to the non-smoothness of the dry friction, which is the basic form of motion of dynamical systems with friction. In this paper, the stick-slip periodic solution in a single-degree-of-freedom oscillator with dry friction is investigated in detail. Under the assumption of kinetic friction being the Coulomb friction, the existence of the stick-slip periodic solution is considered to give out an analytic criterion in a class of friction systems. A two-parameter unfolding diagram is also described. Moreover, the time and states of motion on the boundary of the stick and slip motions are semi-analytically obtained in a single stick-slip period. (general)

  16. Slip length measurement of confined air flow on three smooth surfaces.

    Science.gov (United States)

    Pan, Yunlu; Bhushan, Bharat; Maali, Abdelhamid

    2013-04-02

    An experimental measurement of the slip length of air flow close to three different solid surfaces is presented. The substrate was driven by a nanopositioner moving toward an oscillating glass sphere glued to an atomic force microscopy (AFM) cantilever. A large separation distance was used to get more effective data. The slip length value was obtained by analyzing the amplitude and phase data of the cantilever. The measurements show that the slip length does not depend on the oscillation amplitude of the cantilever. Because of the small difference among the slip lengths of the three surfaces, a simplified analysis method was used. The results show that on glass, graphite, and mica surfaces the slip lengths are 98, 234, and 110 nm, respectively.

  17. Dynamic Behavior of Fault Slip Induced by Stress Waves

    Directory of Open Access Journals (Sweden)

    Guang-an Zhu

    2016-01-01

    Full Text Available Fault slip burst is a serious dynamic hazard in coal mining. A static and dynamic analysis for fault slip was performed to assess the risk of rock burst. A numerical model FLAC3D was established to understand the stress state and mechanical responses of fault rock system. The results obtained from the analysis show that the dynamic behavior of fault slip induced by stress waves is significantly affected by mining depth, as well as dynamic disturbance intensity and the distance between the stope and the fault. The isolation effect of the fault is also discussed based on the numerical results with the fault angle appearing to have the strongest influence on peak vertical stress and velocity induced by dynamic disturbance. By taking these risks into account, a stress-relief technology using break-tip blast was used for fault slip burst control. This technique is able to reduce the stress concentration and increase the attenuation of dynamic load by fracturing the structure of coal and rock. The adoption of this stress-relief method leads to an effective reduction of fault slip induced rock burst (FSIRB occurrence.

  18. 78 FR 62417 - Regulatory Capital Rules: Regulatory Capital, Implementation of Basel III, Capital Adequacy...

    Science.gov (United States)

    2013-10-22

    ..., Standardized Approach for Risk-Weighted Assets, Market Discipline and Disclosure Requirements, Advanced Approaches Risk-Based Capital Rule, and Market Risk Capital Rule AGENCY: Federal Deposit Insurance... Assets, Market Discipline and Disclosure Requirements, Advanced Approaches Risk-Based Capital Rule, and...

  19. Slip cast coating of alumina crucibles

    International Nuclear Information System (INIS)

    Haroun, N.A.; El-Masry, M.A.A.

    1980-01-01

    The development of a process for coating alumina crucibles with MgO protective coat in a two-step slip casting operation is described. The best milling conditions for the alumina used were wet ball milling for 24 hr. MgO had to be calcined at 1200 0 C to minimize hydration. Optimum slip casting conditions for alumina and magnesia were found to be L/S I and pH 3-6 or 9-II for the former, and L/S 3 (alcohol) and pH 8.5-10 for the latter. Sintering of Al 2 O 3 and MgO in the temperature range 1150-500 0 C was investigated. Additions of NiO and MgO lowered the sintered densities at lower temperatures but improved the densification at 1500 0 C. Near theoretical density Al 2 O 3 and MgO crucibles were obtained. A two-step slip casting technique was developed to coat Al 2 O 3 with MgO. Certain slow firing schedules could eliminate the otherwise observed coat-crucible separation and cracks. (author)

  20. Capital Income Tax Coordination and the Income Tax Mix

    DEFF Research Database (Denmark)

    Huizinga, Harry; Nielsen, Søren Bo

    2005-01-01

    in the mix of capital and labor taxes brought on by capital income tax coordination can potentially be welfare reducing. This reflects that in a non-cooperative equilibrium capital income taxes may be more distorting from an international perspective than are labor income taxes. Simulations with a simple...... model calibrated to EU public finance data suggest that countries indeed lower their labor taxes in response to higher coordinated capital income taxes. The overall welfare effects of capital income tax coordination, however, are estimated to remain positive.JEL Classification: F20, H87......Europe has seen several proposals for tax coordination only in the area of capital income taxation, leaving countries free to adjust their labor taxes. The expectation is that highercapital income tax revenues would cause countries to reduce their labor taxes. This paper shows that such changes...

  1. Drag on a slip spherical particle moving in a couple stress fluid

    Directory of Open Access Journals (Sweden)

    E.A. Ashmawy

    2016-06-01

    Full Text Available The creeping motion of a rigid slip sphere in an unbounded couple stress fluid is investigated. The linear slip boundary condition and the vanishing couple stress condition are applied on the surface of the sphere. A simple formula for the drag force acting on a slip sphere translating in an unbounded couple stress fluid is obtained. Special cases of the deduced drag formula are concluded and compared with analogous results in the literature. The normalized drag force experienced by the fluid on the slip sphere is represented graphically and the effects of slip parameter and viscosity coefficients are discussed.

  2. The phase slip factor of the electrostatic cryogenic storage ring CSR

    Science.gov (United States)

    Grieser, Manfred; von Hahn, Robert; Vogel, Stephen; Wolf, Andreas

    2017-07-01

    To determine the momentum spread of an ion beam from the measured revolution frequency distribution, the knowledge of the phase slip factor of the storage ring is necessary. The slip factor was measured for various working points of the cryogenic storage ring CSR at MPI for Nuclear Physics, Heidelberg and was compared with simulations. The predicted functional relationship of the slip factor and the horizontal tune depends on the different islands of stability, which has been experimentally verified. This behavior of the slip factor is in clear contrast to that of magnetic storage rings.

  3. South Korea's Experience with International Capital Flows

    OpenAIRE

    Marcus Noland

    2005-01-01

    South Korea%u2019s experience is unparalleled in its combination of sustained prosperity, capital controls, and financial crisis. Over several decades, South Korea experienced rapid sustained growth in the presence of capital controls. These controls and the de-linking of domestic and international financial markets were an essential component of the country's state-led development strategy. As the country developed, opportunities for easy technological catch-up eroded, requiring more sophist...

  4. Effect of corporate governance on the firms’ structural capital

    Directory of Open Access Journals (Sweden)

    Karima Dhaouadi

    2011-09-01

    Full Text Available The study seeks to understand how the firm‟s ownership structure and the board of directors‟ composition influence the structural capital. The latter is apprehended by three main levers: TMT compensation, innovation, and firm‟s reputation. By mobilizing several panel linear regressions on 274 American firms, the results show that the firms which heavily invest in structural capital are more successful and chaired by the younger and heterogeneous TMT. No disciplinary effect of the board on structural capital has been found. The results support the cognitive theory assumptions. The classic perspective failed to explain the structural capital phenomena. In order to enhance their structural capital, firms must pay a close attention to their board cognitive contribution and not to its disciplinary role.

  5. Leakage flow-induced vibration of an eccentric tube-in-tube slip joint

    International Nuclear Information System (INIS)

    Mulcahy, T.M.

    1985-08-01

    Eccentricity of a specific slip-joint design separating two cantilevered, telescoping tubes did not create any self-excited lateral vibrations that had not been observed previously for a concentric slip joint. In fact, the eccentricity made instabilities less likely to occur, but only marginally. Most important, design rules previously established to avoid instabilities for the concentric slip joint remain valid for the eccentric slip joint. 6 refs., 9 figs., 2 tabs

  6. Mechanism and energetics of dislocation cross-slip in hcp metals

    Science.gov (United States)

    Wu, Zhaoxuan; Curtin, W. A.

    2016-10-01

    Hexagonal close-packed (hcp) metals such as Mg, Ti, and Zr are lightweight and/or durable metals with critical structural applications in the automotive (Mg), aerospace (Ti), and nuclear (Zr) industries. The hcp structure, however, brings significant complications in the mechanisms of plastic deformation, strengthening, and ductility, and these complications pose significant challenges in advancing the science and engineering of these metals. In hcp metals, generalized plasticity requires the activation of slip on pyramidal planes, but the structure, motion, and cross-slip of the associated dislocations are not well established even though they determine ductility and influence strengthening. Here, atomistic simulations in Mg reveal the unusual mechanism of dislocation cross-slip between pyramidal I and II planes, which occurs by cross-slip of the individual partial dislocations. The energy barrier is controlled by a fundamental step/jog energy and the near-core energy difference between pyramidal dislocations. The near-core energy difference can be changed by nonglide stresses, leading to tension-compression asymmetry and even a switch in absolute stability from one glide plane to the other, both features observed experimentally in Mg, Ti, and their alloys. The unique cross-slip mechanism is governed by common features of the generalized stacking fault energy surfaces of hcp pyramidal planes and is thus expected to be generic to all hcp metals. An analytical model is developed to predict the cross-slip barrier as a function of the near-core energy difference and applied stresses and quantifies the controlling features of cross-slip and pyramidal I/II stability across the family of hcp metals.

  7. Closed bone graft epiphysiodesis for avascular necrosis of the capital femoral epiphysis.

    Science.gov (United States)

    Thompson, George H; Lea, Ethan S; Chin, Kenneth; Liu, Raymond W; Son-Hing, Jochen P; Gilmore, Allison

    2013-07-01

    Avascular necrosis (AVN) of the capital femoral epiphysis (CFE) after an unstable slipped capital femoral epiphysis (SCFE), femoral neck fracture or traumatic hip dislocation can result in severe morbidity. Treatment options for immature patients with AVN are limited, including a closed bone graft epiphysiodesis (CBGE). However, it is unclear whether this procedure prevents AVN progression. We investigated whether early MRI screening and CBGE prevented the development of advanced AVN changes in the CFE and the rates of complications with this approach. We prospectively followed all 13 patients (seven boys, six girls) with unstable SCFEs (six patients), femoral neck fractures (five patients), and traumatic hip dislocations (two patients) and evidence of early AVN treated between 1984 and 2012. Mean age at initial injury was 12 years (range, 10-16 years). Nine of the 13 patients had followup of at least 2 years or until conversion to THA (mean, 4.5 years; range, 0.8-8.5 years), including two with unstable SCFEs, the five with femoral neck fractures, and the two with traumatic hip dislocations. All patients had technetium scans and/or MRI within 1 to 2 months of their initial injury (before CBGE) and all had evidence of early (Ficat 0) AVN. Patients were followed clinically and radiographically for AVN progression. Six of the nine hips did not develop typical clinical or radiographic evidence of AVN. These six patients have been followed 6.3 years (range, 4.3-9.1 years) from initial injury and 5.9 years (range, 3.8-8.5 years) from CBGE. The remaining three patients were diagnosed with AVN at periods ranging from 3 to 6 months after CBGE. Early recognition and treatment of AVN with a CBGE may alter the natural history of this complication. Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

  8. Stick-slip and Torsional Friction Factors in Inclined Wellbores

    Directory of Open Access Journals (Sweden)

    Aarsnes Ulf Jakob F.

    2018-01-01

    The model is shown to have a good match with the surface and downhole behavior of two deviated wellbores for depths ranging from 1500 to 3000 meters. In particular, the model replicates the amplitude and period of the oscillations, in both the topside torque and the downhole RPM, as caused by the along-string stick slip. It is further shown that by using the surface behavior of the drill-string during rotational startup, an estimate of the static and dynamic friction factors along the wellbore can be obtained, even during stick-slip oscillations, if axial tension in the drillstring is considered. This presents a possible method to estimate friction factors in the field when off-bottom stick slip is encountered, and points in the direction of avoiding stick slip through the design of an appropriate torsional start-up procedure without the need of an explicit friction test.

  9. Shoe-Floor Interactions in Human Walking With Slips: Modeling and Experiments.

    Science.gov (United States)

    Trkov, Mitja; Yi, Jingang; Liu, Tao; Li, Kang

    2018-03-01

    Shoe-floor interactions play a crucial role in determining the possibility of potential slip and fall during human walking. Biomechanical and tribological parameters influence the friction characteristics between the shoe sole and the floor and the existing work mainly focus on experimental studies. In this paper, we present modeling, analysis, and experiments to understand slip and force distributions between the shoe sole and floor surface during human walking. We present results for both soft and hard sole material. The computational approaches for slip and friction force distributions are presented using a spring-beam networks model. The model predictions match the experimentally observed sole deformations with large soft sole deformation at the beginning and the end stages of the stance, which indicates the increased risk for slip. The experiments confirm that both the previously reported required coefficient of friction (RCOF) and the deformation measurements in this study can be used to predict slip occurrence. Moreover, the deformation and force distribution results reported in this study provide further understanding and knowledge of slip initiation and termination under various biomechanical conditions.

  10. Experimental and finite element analysis of bond-slip in reinforced concrete

    Directory of Open Access Journals (Sweden)

    A. R. V. WOLENSKI

    Full Text Available Abstract The modeling of reinforced concrete structures has taken advantage of the increasing progress on Computational Mechanics, in such way that complex phenomena, such as cracking and crushing, creep, reinforcement yielding, steel-concrete bond loss, can be modeled in a reasonable realistic way, using the proper set of numerical and computational resources. Among several options, the ones based on the Finite Element Method (FEM allow complex analysis simulations of reinforced concrete structures, including the interaction of different nonlinear effects. This paper deals with the nonlinear finite element analysis of the bond-slip between reinforcing steel and concrete, taking into account an experimental study previously performed. The FEM analysis presented uses a combination of resources where the material behavior of concrete is described by the Microplane Constitutive Model, and an embedded reinforcement model is used to represent steel inside the concrete and take into account the effect of bond-slip. The FEM models were created using the INSANE (INteractive Structural ANalysis Environment computational system, open source software that has a set of FEM tools for nonlinear analysis of reinforced concrete structures. The correlations between numerical-experimentals results and several parameters validate the proposed combination of resources and identifies the significance of various effects on the response.

  11. THE CAPITAL STRUCTURE OF VENTURE CAPITAL FIRMS IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Andi Buchari

    2016-10-01

    Full Text Available Venture capital (VC is an important fund source for small and medium enterprises (SMEs and start up, particularly to deliver its main product of equity participation. Therefore, capital structure and factors that affect it are very crucial. This study aims to analyze the capital structure of VC firms in Indonesia using econometric model of panel data regression. This study utilizes secondary data of six years period (2009-2014 monthly financial statements of 27 samples out of 58 VC firms to form 1,944 observations. The study reveals that capital structure of VC firms in Indonesia is dominated by debt/loan rather than capital with DER on average is 136.95%. In addition, the research confirms that VC firms’ capital structure is affected simultaneously by financial aspects which are asset size, profitability, liquidity, asset/investment quality, and earning asset structure. The attentions to financial aspects that affect the VC firms’ capital structure as well as other initiatives related to capital increases are necessary so that the VC firms could carry out its role effectively.

  12. A note on 2-D lithospheric deformation due to a blind strike-slip fault

    Indian Academy of Sciences (India)

    mic deformation. Several researchers have devel- oped models of coseismic lithospheric deformation. Rybicki (1971) found a closed-form analytical solu- tion for the problem of a long vertical strike-slip fault in a two-layer model of the earth. Chinnery and Jovanovich (1972) extended the solution to a three-layer model.

  13. Social Capital and Casino Gambling in U.S. Communities

    Science.gov (United States)

    Tabor Griswold, Mary; Nichols, Mark W.

    2006-01-01

    This paper empirically analyzes the impact that the spread of casino gambling has on social capital in communities throughout the United States. Social capital is a networking process that translates into an individual's effectiveness in the community and workplace, and binds communities together. Several recent studies have also demonstrated a…

  14. Rate-Dependent Slip of Newtonian Liquid at Smooth Surfaces

    International Nuclear Information System (INIS)

    Zhu, Yingxi; Granick, Steve

    2001-01-01

    Newtonian fluids were placed between molecularly smooth surfaces whose spacing was vibrated at spacings where the fluid responded as a continuum. Hydrodynamic forces agreed with predictions from the no-slip boundary condition only provided that flow rate (peak velocity normalized by spacing) was low, but implied partial slip when it exceeded a critical level, different in different systems, correlated with contact angle (surface wettability). With increasing flow rate and partially wetted surfaces, hydrodynamic forces became up to 2--4 orders of magnitude less than expected by assuming the no-slip boundary condition that is commonly stated in textbooks

  15. Seismic Slip on an Oblique Detachment Fault at Low Angles

    Science.gov (United States)

    Janecke, S. U.; Steely, A. N.; Evans, J. P.

    2008-12-01

    Pseudotachylytes are one of the few accepted indicators of seismic slip along ancient faults. Low-angle normal faults have produced few large earthquakes in historic times and low-angle normal faults (detachment faults) are typically severely misoriented relative to a vertical maximum compressive stress. As a result many geoscientists question whether low-angle normal faults produce earthquakes at low angles. Relationships in southern California show that a major low-angle normal-oblique fault slipped at low angles and produced large earthquakes. The exhumed Late Cenozoic West Salton detachment fault preserves spectacular fault- related pseudotachylytes along its fault plane and injected into its hanging wall and footwall. Composite pseudotachylyte zones are up to 1.25 m thick and persists over lateral distances of at least 10's of meters. Pseudotachylyte is common in most thin sections of damaged fault rocks with more than 20% (by volume) of cataclasite. We recognized the presence of original melt using numerous criteria: abundant spherulites in thin sections, injection structures at both the thin-section and outcrop scale, black aphanitic textures, quenched vein margins, variations in microcrystallite textures and/or size with respect to the vein margin, and glassy textures in hand sample. Multiple earthquakes are inferred to produce the layered "stratigraphy" in some exposures of pseudotachylytes. We infer that the West Salton detachment fault formed and slipped at low angles because it nearly perfectly reactivates a Cretaceous ductile thrust system at the half km scale and dips between 10 and 45 degrees. The about 30 degree NNE dip of the detachment fault on the north side of Yaqui Ridge is likely steeper than its dip during detachment slip because there is local steepening on the flanks of the Yaqui Ridge antiform in a contractional stepover of a crosscutting Quaternary San Felipe dextral fault zone. These relationships indicate a low dip on the detachment

  16. Thin Capitalization Rules and Multinational Firm Capital Structure

    NARCIS (Netherlands)

    Blouin, J.; Huizinga, H.P.; Laeven, L.; Nicodeme, G.

    2014-01-01

    Abstract: This paper examines the impact of thin capitalization rules that limit the tax deductibility of interest on the capital structure of the foreign affiliates of US multinationals. We construct a new data set on thin capitalization rules in 54 countries for the period 1982-2004. Using

  17. On the capitalization and cultivation of social capital

    DEFF Research Database (Denmark)

    Waldstrøm, Christian; Svendsen, Gunnar Lind Haase

    2008-01-01

    a dual focus on social capital as both immediately and potentially productive resources, i.e. assets that can be immediately capitalized by individuals as well as ‘cultivated' for future use. We argue that to further operationalize this concept we must distinguish between actual/potential social capital...

  18. Paleomagnetic and structural evidence for oblique slip in a fault-related fold, Grayback monocline, Colorado

    Science.gov (United States)

    Tetreault, J.; Jones, C.H.; Erslev, E.; Larson, S.; Hudson, M.; Holdaway, S.

    2008-01-01

    Significant fold-axis-parallel slip is accommodated in the folded strata of the Grayback monocline, northeastern Front Range, Colorado, without visible large strike-slip displacement on the fold surface. In many cases, oblique-slip deformation is partitioned; fold-axis-normal slip is accommodated within folds, and fold-axis-parallel slip is resolved onto adjacent strike-slip faults. Unlike partitioning strike-parallel slip onto adjacent strike-slip faults, fold-axis-parallel slip has deformed the forelimb of the Grayback monocline. Mean compressive paleostress orientations in the forelimb are deflected 15??-37?? clockwise from the regional paleostress orientation of the northeastern Front Range. Paleomagnetic directions from the Permian Ingleside Formation in the forelimb are rotated 16??-42?? clockwise about a bedding-normal axis relative to the North American Permian reference direction. The paleostress and paleomagnetic rotations increase with the bedding dip angle and decrease along strike toward the fold tip. These measurements allow for 50-120 m of fold-axis-parallel slip within the forelimb, depending on the kinematics of strike-slip shear. This resolved horizontal slip is nearly equal in magnitude to the ???180 m vertical throw across the fold. For 200 m of oblique-slip displacement (120 m of strike slip and 180 m of reverse slip), the true shortening direction across the fold is N90??E, indistinguishable from the regionally inferred direction of N90??E and quite different from the S53??E fold-normal direction. Recognition of this deformational style means that significant amounts of strike slip can be accommodated within folds without axis-parallel surficial faulting. ?? 2008 Geological Society of America.

  19. Technological control of slip casting by the method of PMR

    International Nuclear Information System (INIS)

    Rozental', O.M.; Toropov, Yu.S.; Sobolev, A.S.; Pliner, S.Yu.; Demina, T.E.; Permikina, I.M.

    1980-01-01

    The method of proton magnetic resonance (PMR) is suggested for operational chemico-technological control of slip casting made of oxides of metals in the technology of technical ceramics. PMR spectra of finely dispersed slip casting made of aluminium and zirconium oxides (0.9 mol. of the ZrO 2 shake + 0.1 V 2 O 3 ) are analysed. It is shown that the quality of slip casting out of aqueous suspensions of aluminium and zirconium oxides is abruptly reduced if dP/dW (P - parameter of the PMR line shape, W - humidity) decrease. It is established that slip casting made of zirconium oxide should not be kept in the air more than 5 days, and that of aluminium oxide, more than 3 days at room temperature and should not be exposed to high (> 105 deg C) temperatures. The quality of slip casting is reduced in the regime of too energetic electrosedimentation the optimum regime of electrosedimentation is approximately 5/3 under the conditions of the above experiment

  20. Systematic deficiency of aftershocks in areas of high coseismic slip for large subduction zone earthquakes

    Science.gov (United States)

    Wetzler, Nadav; Lay, Thorne; Brodsky, Emily E.; Kanamori, Hiroo

    2018-01-01

    Fault slip during plate boundary earthquakes releases a portion of the shear stress accumulated due to frictional resistance to relative plate motions. Investigation of 101 large [moment magnitude (Mw) ≥ 7] subduction zone plate boundary mainshocks with consistently determined coseismic slip distributions establishes that 15 to 55% of all master event–relocated aftershocks with Mw ≥ 5.2 are located within the slip regions of the mainshock ruptures and few are located in peak slip regions, allowing for uncertainty in the slip models. For the preferred models, cumulative deficiency of aftershocks within the central three-quarters of the scaled slip regions ranges from 15 to 45%, increasing with the total number of observed aftershocks. The spatial gradients of the mainshock coseismic slip concentrate residual shear stress near the slip zone margins and increase stress outside the slip zone, driving both interplate and intraplate aftershock occurrence near the periphery of the mainshock slip. The shear stress reduction in large-slip regions during the mainshock is generally sufficient to preclude further significant rupture during the aftershock sequence, consistent with large-slip areas relocking and not rupturing again for a substantial time. PMID:29487902

  1. Slip resistance of casual footwear: implications for falls in older adults.

    Science.gov (United States)

    Menz, H B; Lord, S T; McIntosh, A S

    2001-01-01

    A large proportion of falls in older people are caused by slipping. Previous occupational safety research suggests that inadequate footwear may contribute to slipping accidents; however, no studies have assessed the slip resistance of casual footwear. To evaluate the slip resistance of different types of casual footwear over a range of common household surfaces. The slip resistance of men's Oxford shoes and women's fashion shoes with different heel configurations was determined by measuring the dynamic coefficient of friction (DCoF) at heel contact (in both dry and wet conditions) on a bathroom tile, concrete, vinyl flooring and a terra cotta tile using a specially-designed piezoelectric force plate apparatus. Analysis of variance revealed significant shoe, surface, and shoe-surface interaction effects. Men's Oxford shoes exhibited higher average DCoF values than the women's fashion shoes, however, none of the shoes could be considered safe on wet surfaces. Application of a textured sole material did not improve slip resistance of any of the shoes on wet surfaces. Heel geometry influences the slip resistance of casual footwear on common household surfaces. The suboptimal performance of all of the test shoes on wet surfaces suggests that a safety standard for casual footwear is required to assist in the development of safe footwear for older people. Copyright 2001 S. Karger AG, Basel

  2. A Self-Consistent Fault Slip Model for the 2011 Tohoku Earthquake and Tsunami

    Science.gov (United States)

    Yamazaki, Yoshiki; Cheung, Kwok Fai; Lay, Thorne

    2018-02-01

    The unprecedented geophysical and hydrographic data sets from the 2011 Tohoku earthquake and tsunami have facilitated numerous modeling and inversion analyses for a wide range of dislocation models. Significant uncertainties remain in the slip distribution as well as the possible contribution of tsunami excitation from submarine slumping or anelastic wedge deformation. We seek a self-consistent model for the primary teleseismic and tsunami observations through an iterative approach that begins with downsampling of a finite fault model inverted from global seismic records. Direct adjustment of the fault displacement guided by high-resolution forward modeling of near-field tsunami waveform and runup measurements improves the features that are not satisfactorily accounted for by the seismic wave inversion. The results show acute sensitivity of the runup to impulsive tsunami waves generated by near-trench slip. The adjusted finite fault model is able to reproduce the DART records across the Pacific Ocean in forward modeling of the far-field tsunami as well as the global seismic records through a finer-scale subfault moment- and rake-constrained inversion, thereby validating its ability to account for the tsunami and teleseismic observations without requiring an exotic source. The upsampled final model gives reasonably good fits to onshore and offshore geodetic observations albeit early after-slip effects and wedge faulting that cannot be reliably accounted for. The large predicted slip of over 20 m at shallow depth extending northward to 39.7°N indicates extensive rerupture and reduced seismic hazard of the 1896 tsunami earthquake zone, as inferred to varying extents by several recent joint and tsunami-only inversions.

  3. Turbulent flows over superhydrophobic surfaces with shear-dependent slip length

    Science.gov (United States)

    Khosh Aghdam, Sohrab; Seddighi, Mehdi; Ricco, Pierre

    2015-11-01

    Motivated by recent experimental evidence, shear-dependent slip length superhydrophobic surfaces are studied. Lyapunov stability analysis is applied in a 3D turbulent channel flow and extended to the shear-dependent slip-length case. The feedback law extracted is recognized for the first time to coincide with the constant-slip-length model widely used in simulations of hydrophobic surfaces. The condition for the slip parameters is found to be consistent with the experimental data and with values from DNS. The theoretical approach by Fukagata (PoF 18.5: 051703) is employed to model the drag-reduction effect engendered by the shear-dependent slip-length surfaces. The estimated drag-reduction values are in very good agreement with our DNS data. For slip parameters and flow conditions which are potentially realizable in the lab, the maximum computed drag reduction reaches 50%. The power spent by the turbulent flow on the walls is computed, thereby recognizing the hydrophobic surfaces as a passive-absorbing drag-reduction method, as opposed to geometrically-modifying techniques that do not consume energy, e.g. riblets, hence named passive-neutral. The flow is investigated by visualizations, statistical analysis of vorticity and strain rates, and quadrants of the Reynolds stresses. Part of this work was funded by Airbus Group. Simulations were performed on the ARCHER Supercomputer (UKTC Grant).

  4. Shear Stress-Relative Slip Relationship at Concrete Interfaces

    Directory of Open Access Journals (Sweden)

    Keun-Hyeok Yang

    2016-01-01

    Full Text Available This study develops a simple and rational shear stress-relative slip model of concrete interfaces with monolithic castings or smooth construction joints. In developing the model, the initial shear cracking stress and relative slip amount at peak stress were formulated from a nonlinear regression analysis using test data for push-off specimens. The shear friction strength was determined from the generalized equations on the basis of the upper-bound theorem of concrete plasticity. Then, a parametric fitting analysis was performed to derive equations for the key parameters determining the shapes of the ascending and descending branches of the shear stress-relative slip curve. The comparisons of predictions and measurements obtained from push-off tests confirmed that the proposed model provides superior accuracy in predicting the shear stress-relative slip relationship of interfacial shear planes. This was evidenced by the lower normalized root mean square error than those in Xu et al.’s model and the CEB-FIB model, which have many limitations in terms of the roughness of the substrate surface along an interface and the magnitude of equivalent normal stress.

  5. Capital mobility, tax competition, and lobbying for redistributive capital taxation

    OpenAIRE

    Lorz, Jens Oliver

    1996-01-01

    This paper analyzes the impact of international capital mobility on redistributive capital taxation and on lobbying activities by interest groups. It employs a model where different capital endowments lead to a conflict between households concerning their most preferred capital tax rate. Three main results are derived: First, redistributive source based capital taxes or subsidies decline as international tax competition intensifies. Second, lobbying activities of certain interest groups may e...

  6. Slip and fall risk on ice and snow:identification, evaluation and prevention

    OpenAIRE

    Gao, Chuansi

    2004-01-01

    Slip and fall accidents and associated injuries on ice and snow are prevalent among outdoor workers and the general public in winter in many regions of the world. To understand and tackle this multi-factorial problem, a multidisciplinary approach was used to identify and evaluate slip and fall risks, and to propose recommendations for prevention of slips and falls on icy and snowy surfaces. Objectives were to present a systems perspective of slip and fall accidents and related risk factors; t...

  7. The treatment of an unstable slipped capital femoral epiphysis by either intracapsular cuneiform osteotomy or pinning in situ: a comparative study.

    Science.gov (United States)

    Walton, R D M; Martin, E; Wright, D; Garg, N K; Perry, D; Bass, A; Bruce, C

    2015-03-01

    We undertook a retrospective comparative study of all patients with an unstable slipped capital femoral epiphysis presenting to a single centre between 1998 and 2011. There were 45 patients (46 hips; mean age 12.6 years; 9 to 14); 16 hips underwent intracapsular cuneiform osteotomy and 30 underwent pinning in situ, with varying degrees of serendipitous reduction. No patient in the osteotomy group was lost to follow-up, which was undertaken at a mean of 28 months (11 to 48); four patients in the pinning in situ group were lost to follow-up, which occurred at a mean of 30 months (10 to 50). Avascular necrosis (AVN) occurred in four hips (25%) following osteotomy and in 11 (42%) following pinning in situ. AVN was not seen in five hips for which osteotomy was undertaken > 13 days after presentation. AVN occurred in four of ten (40%) hips undergoing emergency pinning in situ, compared with four of 15 (47%) undergoing non-emergency pinning. The rate of AVN was 67% (four of six) in those undergoing pinning on the second or third day after presentation. Pinning in situ following complete reduction led to AVN in four out of five cases (80%). In comparison, pinning in situ following incomplete reduction led to AVN in 7 of 21 cases (33%). The rate of development of AVN was significantly higher following pinning in situ with complete reduction than following intracapsular osteotomy (p = 0.048). Complete reduction was more frequent in those treated by emergency pinning and was strongly associated with AVN (p = 0.005). Non-emergency intracapsular osteotomy may have a protective effect on the epiphyseal vasculature and should be undertaken with a delay of at least two weeks. The place of emergency pinning in situ in these patients needs to be re-evaluated, possibly in favour of an emergency open procedure or delayed intracapsular osteotomy. Non-emergency pinning in situ should be undertaken after a delay of at least five days, with the greatest risk at two and three days after

  8. Shell Tectonics: A Mechanical Model for Strike-slip Displacement on Europa

    Science.gov (United States)

    Rhoden, Alyssa Rose; Wurman, Gilead; Huff, Eric M.; Manga, Michael; Hurford, Terry A.

    2012-01-01

    We introduce a new mechanical model for producing tidally-driven strike-slip displacement along preexisting faults on Europa, which we call shell tectonics. This model differs from previous models of strike-slip on icy satellites by incorporating a Coulomb failure criterion, approximating a viscoelastic rheology, determining the slip direction based on the gradient of the tidal shear stress rather than its sign, and quantitatively determining the net offset over many orbits. This model allows us to predict the direction of net displacement along faults and determine relative accumulation rate of displacement. To test the shell tectonics model, we generate global predictions of slip direction and compare them with the observed global pattern of strike-slip displacement on Europa in which left-lateral faults dominate far north of the equator, right-lateral faults dominate in the far south, and near-equatorial regions display a mixture of both types of faults. The shell tectonics model reproduces this global pattern. Incorporating a small obliquity into calculations of tidal stresses, which are used as inputs to the shell tectonics model, can also explain regional differences in strike-slip fault populations. We also discuss implications for fault azimuths, fault depth, and Europa's tectonic history.

  9. Rethinking the economics of capital mobility and capital controls

    Directory of Open Access Journals (Sweden)

    Thomas I. Palley

    2009-09-01

    Full Text Available This paper reexamines the issue of international financial capital mobility, which is today's economic orthodoxy. Discussion is often framed in terms of the impossible trinity. That framing distorts discussion by representing capital mobility as having equal significance with sovereign monetary policy and control over exchange rates. It also distorts discussion by ignoring possibilities for coordinated monetary policy and exchange rates, and for managed capital flows. The case for capital mobility rests on neo-classical economic efficiency arguments and neo-liberal political arguments. The case against capital mobility is based on Keynesian macroeconomic inefficiency arguments, neo-Walrasian market failure arguments, and neo-Marxian arguments regarding distortion of the social structure of accumulation. Close examination shows the case for capital mobility to be extremely flimsy, pointing to the ideological dimension behind today's policy orthodoxy.

  10. Asymmetric Barrier Lyapunov Function-Based Wheel Slip Control for Antilock Braking System

    Directory of Open Access Journals (Sweden)

    Xiaolei Chen

    2015-01-01

    Full Text Available As an important device of the aircraft landing system, the antilock braking system (ABS has a function to avoid aircraft wheels self-locking. To deal with the strong nonlinear characteristics, complex nonlinear control schemes are applied in ABS. However, none of existing control schemes focus on the braking operating status, which directly reflects wheels self-locking degree. In this paper, the braking operating status region is divided into three regions: the healthy region, the light slip region, and the deep slip region. An ABLF-based wheel slip controller is proposed for ABS to constrain the braking system operating status in the healthy region and the light slip region. Therefore the ABS will be prevented from operating in the deep slip region. Under the proposed control scheme, self-locking is avoided completely and zero steady state error tracking of the wheel optimal slip ratio is implemented. The Hardware-In-Loop (HIL experiments have validated the effectiveness of the proposed controller.

  11. Bridges in social capital: a review of the definitions and the social capital of social capital researchers

    OpenAIRE

    Akcomak, S.

    2009-01-01

    There has been a recent surge of interest in social economics and social capital. Articles on social capital that are published in the last five years constitute more than 60 percent of all articles on social capital. Research on social capital is now massive and spans sociology, economics, management, political science and health sciences. Despite this interest there is still not a consensus on the definition and the measurement of social capital. This paper argues that this is due to lack o...

  12. Stability Analysis of Static Slip-Energy Recovery Drive via ...

    African Journals Online (AJOL)

    The stability of the sub synchronous static slip energy recovery scheme for the speed control of slip-ring induction motor is presented. A set of nonlinear differential equations which describe the system dynamics are derived and linearized about an operating point using perturbation technique. The Eigenvalue analysis of the ...

  13. Surgical results of the slipped medial rectus muscle after hang back recession surgery

    Directory of Open Access Journals (Sweden)

    Yasar Duranoglu

    2014-12-01

    Full Text Available AIM:To analyze the surgical results of a slipped medial rectus muscle (MRM after hang back recession surgery for esotropia.METHODS:Twenty-one patients who underwent re-exploration for diagnosed slipped muscle after hang back recession surgery were included in this retrospective study. Dynamic magnetic resonance imaging was performed to identify the location of the slipped muscle. Ocular motility was evaluated with assessment with prism and cover test in gaze at cardinal positions. The operations were performed by the same consultant. Intraoperative forced duction test was performed under general anesthesia. The empty sheath of the slipped MRM was resected and the muscle was advanced to the original insertion site in all patients.RESULTS:The average age of 21 patients who hadconsecutive exotropia with a slipped MRM at the time of presentation was 17.4±5.4y (5-50y. The average duration between the first operation and the diagnosis of the slipped muscle was 25mo (12 to 36mo. The mean follow up after the corrective surgery was 28mo. The mean preoperative adduction limitation in the field of action of the slipped muscle was -2.26 (ranging from -1 to -4. All patients had full adduction postoperatively.CONCLUSION:The diagnosis of the slipped muscle should be confirmed during the strabismus surgery. The slipped muscle may be caused due to insufficient suture and excessive rubbing of the eye. When divergent strabismus is observed after the recession of the MRM, a slipped muscle should be considered in the differential diagnosis.

  14. Seismic and geodetic signatures of fault slip at the Slumgullion Landslide Natural Laboratory

    Science.gov (United States)

    Gomberg, J.; Schulz, W.; Bodin, P.; Kean, J.

    2011-01-01

    We tested the hypothesis that the Slumgullion landslide is a useful natural laboratory for observing fault slip, specifically that slip along its basal surface and side-bounding strike-slip faults occurs with comparable richness of aseismic and seismic modes as along crustal- and plate-scale boundaries. Our study provides new constraints on models governing landslide motion. We monitored landslide deformation with temporary deployments of a 29-element prism array surveyed by a robotic theodolite and an 88-station seismic network that complemented permanent extensometers and environmental instrumentation. Aseismic deformation observations show that large blocks of the landslide move steadily at approximately centimeters per day, possibly punctuated by variations of a few millimeters, while localized transient slip episodes of blocks less than a few tens of meters across occur frequently. We recorded a rich variety of seismic signals, nearly all of which originated outside the monitoring network boundaries or from the side-bounding strike-slip faults. The landslide basal surface beneath our seismic network likely slipped almost completely aseismically. Our results provide independent corroboration of previous inferences that dilatant strengthening along sections of the side-bounding strike-slip faults controls the overall landslide motion, acting as seismically radiating brakes that limit acceleration of the aseismically slipping basal surface. Dilatant strengthening has also been invoked in recent models of transient slip and tremor sources along crustal- and plate-scale faults suggesting that the landslide may indeed be a useful natural laboratory for testing predictions of specific mechanisms that control fault slip at all scales.

  15. SLOW SLIP EVENTS: PARAMETERS, CONDITIONS OF OCCURRENCE, AND FUTURE RESEARCH PROSPECTS

    Directory of Open Access Journals (Sweden)

    G. G. Kocharyan

    2014-01-01

    Full Text Available Slow slip events along faults and fractures are reviewed. Such inter-block displacements can be recorded at various scale levels and considered as transitional from quasi-stable (creep to dynamic slip (earthquake. Such events include seismogenic slip along faults at velocities by one to three orders lower than those in case of 'normal' earthquakes, as well as aseismic slip cases. Discovering such events facilitates better understanding of how energy accumulated during deformation of the crust is released.Studying conditions and the evolution of transitional regimes can provide new important information on the structure and regularities of deformation in fault zones.Data from latest publications by different authors are consolidated, and the data analysis results are presented. Over 170 slow slip events are reviewed. Based on the consolidated data and modelling results obtained by the authors, relationships between parameters of the reviewed process are established, scale relations between the events are considered, and a first-approximation analysis is conducted for impacts of geomaterial characteristics on various deformation regimes.Low-frequency earthquake foci and slow slip sites are most typically located in zones of transition from stable creep areas to seismogenic segments of the discontinuity (Fig. 3 It can be logically supposed that in such transitional zones, the interface has specific frictional properties providing for a regime that can be termed as 'conditionally stable slip'.The duration of slow deformation events is roughly proportional to the released seismic moment, while such a ratio is close to self-similarity in case of 'normal' earthquakes (Fig. 4. In case of slow slip, an area of the displaced section is larger by many factors than the corresponding value for an earthquake with the same seismic moment, while an average displacement amplitude along the fault is significantly smaller (Figures 5 and 6. Velocities of slip

  16. Slip Zone versus Damage Zone Micromechanics, Arima-Takasuki Tectonic Line, Japan

    Science.gov (United States)

    White, J. C.; Lin, A.

    2017-12-01

    The Arima-Takasuki Tectonic Line (ATTL) of southern Honshu, Japan is defined by historically active faults and multiple splays producing M7 earthquakes. The damage zone of the ATTL comprises a broad zone of crushed, comminuted and pulverized granite/rhyolite1,2containing cm-scale slip zones and highly comminuted injection veins. In this presentation, prior work on the ATTL fault rocks is extending to include microstructural characterization by transmission electron microscopy (TEM) from recent trenching of the primary slip zone, as well as secondary slip zones. This is necessary to adequately characterize the extremely fine-grained material (typically less than 1mm) in both damage and core zones. Damage zone material exhibits generally random textures3 whereas slip zones are macroscopically foliated, and compositionally layered, notwithstanding a fairly homogeneous protolith. The latter reflects fluid-rock interaction during both coseismic and interseismic periods. The slip zones are microstructurally heterogeneous at all scales, comprising not only cataclasites and phyllosilicate (clay)-rich gouge zones, but Fe/Mn pellets or clasts that are contained within gouge. These structures appear to have rolled and would suggest rapid recrystallization and/or growth. A central question related to earthquake recurrence along existing faults is the nature of the gouge. In both near-surface exposures and ongoing drilling at depth, "plastic" or "viscous" gouge zones comprise ultra-fine-grained clay-siliciclastic particles that would not necessarily respond in a simple frictional manner. Depending on whether the plastic nature of these slip zones develops during or after slip, subsequent focusing of slip within them could be complicated. 1 Mitchell, T.A., Ben-Zion, Y., Shimamoto, T., 2011. Ear. Planet. Sci. Lett. 308, 284-297. 2 Lin, A., Yamashita, K, Tanaka, M. J., 2013. Struc. Geol. 48, 3-13. 3 White, J.C., Lin, A. 2016. Proc. AGU Fall Mtg., T42-02 San Francisco.

  17. On flows of viscoelastic fluids under threshold-slip boundary conditions

    Science.gov (United States)

    Baranovskii, E. S.

    2018-03-01

    We investigate a boundary-value problem for the steady isothermal flow of an incompressible viscoelastic fluid of Oldroyd type in a 3D bounded domain with impermeable walls. We use the Fujita threshold-slip boundary condition. This condition states that the fluid can slip along a solid surface when the shear stresses reach a certain critical value; otherwise the slipping velocity is zero. Assuming that the flow domain is not rotationally symmetric, we prove an existence theorem for the corresponding slip problem in the framework of weak solutions. The proof uses methods for solving variational inequalities with pseudo-monotone operators and convex functionals, the method of introduction of auxiliary viscosity, as well as a passage-to-limit procedure based on energy estimates of approximate solutions, Korn’s inequality, and compactness arguments. Also, some properties and estimates of weak solutions are established.

  18. Lattice Boltzmann study of slip flow over structured surface with transverse slots

    Science.gov (United States)

    Chen, Wei; Wang, Kai; Wang, Lei; Hou, Guoxiang; Leng, Wenjun

    2018-04-01

    Slip flow over structured superhydrophobic surface with transverse slots is investigated by the lattice Boltzmann method. The Shan-Chen multiphase model is employed to simulate the flow over gas bubbles in the slots. The Carnahan-Starling equation of state is applied to obtain large density ratio. The interface thickness of the multiphase model is discussed. We find that the Cahn number Cn should be smaller than 0.02 when the temperature T = 0.5T c to restrict the influence of interface thickness on slip length. Influences of slot fraction on slip length is then studied, and the result is compared with single LB simulation of which the interface is treated as free-slip boundary. The slip length obtained by the multiphase model is a little smaller. After that, the shape of the liquid-gas interface is considered, and simulations with different initial protrusion angles and capillary numbers are performed. Effective slip length as a function of initial protrusion angle is obtained. The result is in qualitative agreement with a previous study and main features are reproduced. Furthermore, the influence of Capillary number Ca is studied. Larger Ca causes larger interface deformation and smaller slip length. But when the interface is concaving into the slot, this influence is less obvious.

  19. Numerical Simulation of Methane Slip in Dual Fuel Marine Engines

    OpenAIRE

    Han, Jaehyun; Jensen, Michael Vincent; Pang, Kar Mun; Walther, Jens Honore; Schramm, Jesper; Bae, Choongsik

    2017-01-01

    The methane slip is the problematic issue for the engines using natural gas(NG). Because methane is more powerful greenhouse gas (GHG) than CO2, understanding of the methane slip during gas exchange process of the engines is essential. In this study, the influence of the gas pipe geometry and the valve timings on the methane slip was investigated. MAN L28/32DF engine was modeled to simulate the gas exchange process of the four stroke NG-diesel dual fuel engines. The mesh size of the model was...

  20. Detection of slip from multiple sites in an artificial finger

    Energy Technology Data Exchange (ETDEWEB)

    Muridan, N; Chappell, P H; Cranny, A; White, N M [Electronic Systems and Devices Group, School of Electronics and Computer Science, University of Southampton, SO17 1BJ (United Kingdom); Cotton, D P J, E-mail: nm07r@ecs.soton.ac.u [Nanoscience Centre, University of Cambridge, Cambridge (United Kingdom)

    2009-07-01

    A Piezoelectric thick-film sensor is a good candidate for the extraction of information from object slip in hand prosthesis. Five slip sensors were fabricated on different linkages of an artificial hand. The signals from each sensor were compared to the output from the sensor mounted on the fingertip. An analysis of the output signals from all the sensors indicates that the linkage sensors also produce similar output signals to the fingertip sensor. In the next phase of the research, velocity and acceleration of the slipped object will be considered in the analysis.

  1. Episodic tremor and slip explained by fluid-enhanced microfracturing and sealing

    Science.gov (United States)

    Bernaudin, M.; Gueydan, F.

    2017-12-01

    A combination of non-volcanic tremor and transient slow slip events behaviors is commonly observed at plate interface, between locked/seismogenic zone at low depths and stable/ductile creep zone at larger depths. This association defines Episodic Tremor and Slip, systematically highlighted by over-pressurized fluids and near failure shear stress conditions. Here we propose a new mechanical approach that provides for the first time a mechanical and field-based explanation of the observed association between non-volcanic tremor and slow slip events. In contrast with more classical rate-and-state models, this physical model uses a ductile rheology with grain size sensitivity, fluid-driven microfracturing and sealing (e.g. grain size reduction and grain growth) and related pore fluid pressure fluctuations. We reproduce slow slip events by transient ductile strain localization as a result of fluid-enhanced microfracturing and sealing. Moreover, occurrence of macrofracturing during transient strain localization and local increase in pore fluid pressure well simulate non-volcanic tremor. Our model provides therefore a field-based explanation of episodic tremor and slip and moreover predicts the depth and temperature ranges of their occurrence in subduction zones. It implies furthermore that non-volcanic tremor and slow slip events are physically related.

  2. Bourdieu’s Cultural Capital in Relation to Food Choices: A Systematic Review of Cultural Capital Indicators and an Empirical Proof of Concept

    Science.gov (United States)

    Kamphuis, Carlijn B. M.; Jansen, Tessa; Mackenbach, Johan P.; van Lenthe, Frank J.

    2015-01-01

    Objective Unhealthy food choices follow a socioeconomic gradient that may partly be explained by one’s ‘cultural capital’, as defined by Bourdieu. We aim 1) to carry out a systematic review to identify existing quantitative measures of cultural capital, 2) to develop a questionnaire to measure cultural capital for food choices, and 3) to empirically test associations of socioeconomic position with cultural capital and food choices, and of cultural capital with food choices. Design We systematically searched large databases for the key-word ‘cultural capital’ in title or abstract. Indicators of objectivised cultural capital and family institutionalised cultural capital, as identified by the review, were translated to food choice relevant indicators. For incorporated cultural capital, we used existing questionnaires that measured the concepts underlying the variety of indicators as identified by the review, i.e. participation, skills, knowledge, values. The questionnaire was empirically tested in a postal survey completed by 2,953 adults participating in the GLOBE cohort study, The Netherlands, in 2011. Results The review yielded 113 studies that fulfilled our inclusion criteria. Several indicators of family institutionalised (e.g. parents’ education completed) and objectivised cultural capital (e.g. possession of books, art) were consistently used. Incorporated cultural capital was measured with a large variety of indicators (e.g. cultural participation, skills). Based on this, we developed a questionnaire to measure cultural capital in relation to food choices. An empirical test of the questionnaire showed acceptable overall internal consistency (Cronbach’s alpha of .654; 56 items), and positive associations between socioeconomic position and cultural capital, and between cultural capital and healthy food choices. Conclusions Cultural capital may be a promising determinant for (socioeconomic inequalities in) food choices. PMID:26244763

  3. The Impact of Capital Structure on Economic Capital and Risk Adjusted Performance

    OpenAIRE

    Porteous, Bruce; Tapadar, Pradip

    2008-01-01

    The impact that capital structure and capital asset allocation have on financial services firm economic capital and risk adjusted performance is considered. A stochastic modelling approach is used in conjunction with banking and insurance examples. It is demonstrated that gearing up Tier 1 capital with Tier 2 capital can be in the interests of bank Tier 1 capital providers, but may not always be so for insurance Tier 1 capital providers. It is also shown that, by allocating a bank or insuranc...

  4. SLIP VELOCITY IN PULSED DISC AND DOUGHNUT EXTRACTION COLUMN

    Directory of Open Access Journals (Sweden)

    Mohammad Outokesh

    2011-09-01

    Full Text Available In the present work, slip velocity has been measured in a 76 mm diameter pulsed disc and doughnut extraction column for four different liquid-liquid systems. The effects of operating variables including pulsation intensity and dispersed and continuous phase flow rates on slip velocity have been investigated. The existence of three different operational regimes, namely mixersettler, transition, and emulsion regimes, was observed when the energy input was changed. Empirical correlations are derived for prediction of the slip velocity in terms of operating variables, physical properties of the liquid systems, and column geometry for different regimes. Good agreement between prediction and experiments was found for all operating conditions that were investigated.

  5. Numerical study of the effect of Navier slip on the driven cavity flow

    KAUST Repository

    He, Qiaolin

    2009-10-01

    We study the driven cavity flow using the Navier slip boundary condition. Our results have shown that the Navier slip boundary condition removes the corner singularity induced by the no-slip boundary condition. In the low Reynolds number case, the behavior of the tangential stress is examined and the results are compared with the analytic results obtained in [14]. For the high Reynolds number, we study the effect of the slip on the critical Reynolds number for Hopf bifurcation. Our results show that the first Hopf bifurcation critical Reynolds number is increasing with slip length. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Fracture energy of stick-slip events in a large scale biaxial experiment

    International Nuclear Information System (INIS)

    Okubo, P.G.; Dieterich, J.H.

    1981-01-01

    The concept of apparent fracture energy for the shear failure process is employed by many authors in modeling earthquake sources as dynamically extending shear cracks. Using records of shear strain and relative displacement from stick-slip events generated along a simulated, prepared fault surface in a large (1.5m x 1.5m x 0.4m) granite block and a slip-weakening model for the fault, direct estimates of the apparent shear fracture energy of the stick-slip events have been obtained. For events generated on a finely ground fault surface, apparent fracture energy ranges from 0.06 J/m 2 at a normal stress of 1.1 MPa to 0.8 J/m 2 at a normal stress of 4.6 MPa. In contrast to estimates for tensile crack formation, we find that the apparent fracture energy of stick-slip events increases linearly with normal stress. The results for the slip-weakening model for the stick-slip events are generally consistent with constitutive fault models suggested by observations of stable sliding in smaller scale experiments

  7. Influence of competition between intragranular dislocation nucleation and intergranular slip transfer on mechanical properties of ultrafine-grained metals

    International Nuclear Information System (INIS)

    Tsuru, Tomohito; Kaji, Yoshiyuki; Aoyagi, Yoshiteru; Shimokawa, Tomotsugu

    2013-01-01

    Huge-scale atomistic simulations of shear deformation tests to the aluminum polycrystalline thin film containing the Frank-Read source are performed to elucidate the relationship between the inter- and intragranular plastic deformation processes and the mechanical properties of ultrafine-grained metals. Two-types of polycrystalline models, which consist of several grain boundaries reproducing easy and hard slip transfer, respectively, are prepared to investigate the effect of grain boundary on flow stress. While the first plastic deformation occurs by the dislocation bow-out motion within the grain region for both models, the subsequent plastic deformation is strongly influenced by the resistance of the slip transfer by dislocation transmission through grain boundaries. The influence of the competition between the intragranular dislocation nucleation and intergranular slip transfer on the material strength is considered. The nanostructured material's strength depending on local defect structures associated with grain size and dislocation source length is assessed quantitatively. (author)

  8. Slip length crossover on a graphene surface

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Zhi, E-mail: liangz3@rpi.edu [Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Keblinski, Pawel, E-mail: keplip@rpi.edu [Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-04-07

    Using equilibrium and non-equilibrium molecular dynamics simulations, we study the flow of argon fluid above the critical temperature in a planar nanochannel delimited by graphene walls. We observe that, as a function of pressure, the slip length first decreases due to the decreasing mean free path of gas molecules, reaches the minimum value when the pressure is close to the critical pressure, and then increases with further increase in pressure. We demonstrate that the slip length increase at high pressures is due to the fact that the viscosity of fluid increases much faster with pressure than the friction coefficient between the fluid and the graphene. This behavior is clearly exhibited in the case of graphene due to a very smooth potential landscape originating from a very high atomic density of graphene planes. By contrast, on surfaces with lower atomic density, such as an (100) Au surface, the slip length for high fluid pressures is essentially zero, regardless of the nature of interaction between fluid and the solid wall.

  9. HUMAN CAPITAL: CAUSE AND EFFECT OF THE ECONOMIC GROWTH. AN EMPIRICAL ANALYSIS

    OpenAIRE

    NEAGU OLIMPIA

    2013-01-01

    From the birth of the human capital theory, economists were interested to find evidences showing the impact of the human capital on the economic output, discussing and debating more or less the effect of economic growth on the accumulation of human capital in the economy and the association between education and health. The paper aims to test several econometric models to explain the relationship between human capital and economic output. Using World Bank data, 17 countries with the fastest e...

  10. Human Capital and Optimal Positive Taxation of Capital Income

    NARCIS (Netherlands)

    B. Jacobs (Bas); A.L. Bovenberg (Lans)

    2005-01-01

    textabstractThis paper analyzes optimal linear taxes on capital and labor incomes in a life-cycle model of human capital investment, financial savings, and labor supply with heteroge- nous individuals. A dual income tax with a positive marginal tax rate on not only labor income but also capital

  11. Gait adaptations to awareness and experience of a slip when walking on a cross-slope.

    Science.gov (United States)

    Lawrence, Daniel; Domone, Sarah; Heller, Ben; Hendra, Timothy; Mawson, Susan; Wheat, Jon

    2015-10-01

    Falls that occur as a result of a slip are one of the leading causes of injuries, particularly in the elderly population. Previous studies have focused on slips that occur on a flat surface. Slips on a laterally sloping surface are important and may be related to different mechanisms of balance recovery. This type of slip might result in different gait adaptations to those previously described on a flat surface, but these adaptations have not been investigated. The aim of this study was to assess whether, when walking on a cross-slope, young adults adapted their gait when made aware of a potential slip, and having experienced a slip. Gait parameters were compared for three conditions--(1) Normal walking; (2) Walking after being made aware of a potential slip (participants were told that a slip may occur); (3) Walking after experiencing a slip (Participants had already experienced at least one slip induced using a soapy contaminant). Gait parameters were only analysed for trials in which there was no slippery contaminant present on the walkway. Stride length and walking velocity were significantly reduced, and stance duration was significantly greater in the awareness and experience conditions compared to normal walking, with no significant differences in any gait parameters between the awareness and experience conditions. In addition, 46.7% of the slip trials resulted in a fall. This is higher than reported for slips induced on a flat surface, suggesting slips on a cross-slope are more hazardous. This would help explain the more cautious gait patterns observed in both the awareness and experience conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. A novel wireless piezoelectric tire sensor for the estimation of slip angle

    International Nuclear Information System (INIS)

    Erdogan, G; Alexander, L; Rajamani, R

    2010-01-01

    This paper introduces a simple approach for the analysis of tire deformation and proposes a new piezoelectric tire sensor for physically meaningful measurements of tire deformations. Tire deformation measurements in the contact patch can be used for the estimation of slip angle, tire forces, slip ratio and tire–road friction coefficient. The specific case of a wireless tire deformation sensor for the estimation of slip angle is taken up in this paper. A sensor in which lateral sidewall deformation can be decoupled from radial deformation is designed. The slope of the lateral deflection curve in the contact patch is used to calculate slip angle. A specially constructed tire test rig is used to experimentally evaluate the performance of the developed sensor. Results show that the developed sensor can accurately estimate slip angles up to values of 5°

  13. Dependence of dislocation structure on orientation and slip systems in highly oriented nanotwinned Cu

    DEFF Research Database (Denmark)

    Lu, Qiuhong; You, Zesheng; Huang, Xiaoxu

    2017-01-01

    slip Mode I and II are active with dominance of Mode II. In structures deformed at 45° dislocations from slip Modes I, II and III are identified, where Mode III dislocations consist of partial dislocations moving along the TBs and full dislocations inside the twin lamellae gliding on the slip planes...... parallel to the twin plane. The analysis of the dislocation structures illustrate the strong correlation between active slip systems and the dislocation structure and the strong effect of slip mode anisotropy on both the flow stress and strain hardening rate of nanotwinned Cu....

  14. Geodetic slip solutions for the Mw = 7.4 Champerico (Guatemala) earthquake of 2012 November 7 and its postseismic deformation

    Science.gov (United States)

    Ellis, Andria P.; DeMets, Charles; Briole, Pierre; Molina, Enrique; Flores, Omar; Rivera, Jeffrey; Lasserre, Cécile; Lyon-Caen, Hélène; Lord, Neal

    2015-05-01

    As the first large subduction thrust earthquake off the coast of western Guatemala in the past several decades, the 2012 November 7 Mw = 7.4 earthquake offers the first opportunity to study coseismic and postseismic behaviour along a segment of the Middle America trench where frictional coupling makes a transition from weak coupling off the coast of El Salvador to strong coupling in southern Mexico. We use measurements at 19 continuous GPS sites in Guatemala, El Salvador and Mexico to estimate the coseismic slip and postseismic deformation of the November 2012 Champerico (Guatemala) earthquake. An inversion of the coseismic offsets, which range up to ˜47 mm at the surface near the epicentre, indicates that up to ˜2 m of coseismic slip occurred on a ˜30 × 30 km rupture area between ˜10 and 30 km depth, which is near the global CMT centroid. The geodetic moment of 13 × 1019 N m and corresponding magnitude of 7.4 both agree well with independent seismological estimates. Transient postseismic deformation that was recorded at 11 GPS sites is attributable to a combination of fault afterslip and viscoelastic flow in the lower crust and/or mantle. Modelling of the viscoelastic deformation suggests that it constituted no more than ˜30 per cent of the short-term postseismic deformation. GPS observations that extend six months after the earthquake are well fit by a model in which most afterslip occurred at the same depth or directly downdip from the rupture zone and released energy equivalent to no more than ˜20 per cent of the coseismic moment. An independent seismological slip solution that features more highly concentrated coseismic slip than our own fits the GPS offsets well if its slip centroid is translated ˜50 km to the west to a position close to our slip centroid. The geodetic and seismologic slip solutions thus suggest bounds of 2-7 m for the peak slip along a region of the interface no larger than 30 × 30 km.

  15. Local void and slip model used in BODYFIT-2PE

    International Nuclear Information System (INIS)

    Chen, B.C.J.; Chien, T.H.; Kim, J.H.; Lellouche, G.S.

    1983-01-01

    A local void and slip model has been proposed for a two-phase flow without the need of fitting any empirical parameters. This model is based on the assumption that all bubbles have reached their terminal rise velocities in the two-phase region. This simple model seems to provide reasonable calculational results when compared with the experimental data and other void and slip models. It provides a means to account for the void and slip of a two-phase flow on a local basis. This is particularly suitable for a fine mesh thermal-hydraulic computer program such as BODYFIT-2PE

  16. Numerical study of effects of accommodation coefficients on slip phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Jae; Kwon, Oh Joon [KAIST, Daejeon (Korea, Republic of)

    2015-05-15

    An unstructured mesh Navier-Stokes solver employing a Maxwell slip boundary condition was developed. The present flow solver was applied to the simulation of flows around an axisymmetric hollow cylinder in a Mach 10.4 free stream, known as Calspan-UB Research Center (CUBRC) Run 14 case, and the velocity slip and the temperature jump on the cylinder surface were investigated. The effect of tangential momentum and thermal accommodation coefficients used in the Maxwell condition was also investigated by adjusting their values. The results show that the reverse flow region is developed on the body surface due to the interaction between the shock and the boundary layer. Also, the shock impingement makes pressure high. The flow properties on the surface agree well with the experimental data, and the velocity slip and the temperature jump vary consistently with the local Knudsen number change. The accommodation coefficients affect the slip phenomena and the size of the flow region. The slip phenomena become larger when both tangential momentum and thermal accommodation coefficients are decreased. However, the range of the reverse flow region decreases when the momentum accommodation coefficient is decreased. The characteristics of the momentum and thermal accommodation coefficients also are overlapped when they are altered together.

  17. Solute softening and defect generation during prismatic slip in magnesium alloys

    Science.gov (United States)

    Yi, Peng; Cammarata, Robert C.; Falk, Michael L.

    2017-12-01

    Temperature and solute effects on prismatic slip of 〈a〉 dislocations in Mg are studied using molecular dynamics simulation. Prismatic slip is controlled by the low mobility screw dislocation. The screw dislocation glides on the prismatic plane through alternating cross-slip between the basal plane and the prismatic plane. In doing so, it exhibits a locking-unlocking mechanism at low temperatures and a more continuous wavy propagation at high temperatures. The dislocation dissociates into partials on the basal plane and the constriction formation of the partials is identified to be the rate-limiting process for unlocking. In addition, the diffusion of partials on the basal plane enables the formation of jogs and superjogs for prismatic slip, which lead to the generation of vacancies and dislocation loops. Solute softening in Mg alloys was observed in the presence of both Al and Y solute. The softening in prismatic slip is found to be due to solute pinning on the basal plane, instead of the relative energy change of the screw dislocation on the basal and prismatic planes, as has been hypothesized.

  18. Fault slip and earthquake recurrence along strike-slip faults — Contributions of high-resolution geomorphic data

    KAUST Repository

    Zielke, Olaf; Klinger, Yann; Arrowsmith, J. Ramon

    2015-01-01

    to contribute to better-informed models of EQ recurrence and slip-accumulation patterns. After reviewing motivation and background, we outline requirements to successfully reconstruct a fault's offset accumulation pattern from geomorphic evidence. We address

  19. Ductility improvement by twinning and twin–slip interaction in a Mg-Y alloy

    International Nuclear Information System (INIS)

    Zhou, Na; Zhang, Zhenyan; Jin, Li; Dong, Jie; Chen, Bin; Ding, Wenjiang

    2014-01-01

    Highlights: • A high elongation of ∼33% was achieved for magnesium alloy through common extrusion. • Basal slip and extension twinning are the dominant deformation modes for the high ductility. • Non-basal slip, contraction twinning and twin-slip interaction also contribute to the ductility. - Abstract: An extruded Mg-3.0Y alloy with non-basal texture of 〈42 ¯ 2 ¯ 3〉 component was fabricated by common extrusion and exhibited a high elongation of ∼33%. The deformation modes and microstructure evolution of the extruded Mg-3.0Y alloy during the tensile test at room temperature were investigated to explore the reasons for the high ductility by transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD). The results suggested that texture changed from 〈42 ¯ 2 ¯ 3〉 to 〈101 ¯ 0〉 component during the tensile deformation, which is attributed the slip and twinning activity. Basal slip and extension twinning are the dominant deformation modes for the high ductility. Meanwhile, the activation of non-basal slip, contraction twinning and twin–slip interaction also contributes to the good ductility of Mg-3.0Y alloy

  20. Friction, slip and structural inhomogeneity of the buried interface

    International Nuclear Information System (INIS)

    Dong, Y; Wu, J; Martini, A; Li, Q

    2011-01-01

    An atomistic model of metallic contacts using realistic interatomic potentials is used to study the connection between friction, slip and the structure of the buried interface. Incommensurability induced by misalignment and lattice mismatch is modeled with contact sizes that are large enough to observe superstructures formed by the relative orientations of the surfaces. The periodicity of the superstructures is quantitatively related to inhomogeneous shear stress distributions in the contact area, and a reduced order model is used to clarify the connection between friction and structural inhomogeneity. Finally, the movement of atoms is evaluated before, during and after slip in both aligned and misaligned contacts to understand how the interfacial structure affects the mechanisms of slip and the corresponding frictional behavior

  1. From political capitalism to clientelist capitalism? The case of Croatia

    OpenAIRE

    Vladimir Cvijanovic; Denis Redzepagic

    2011-01-01

    The paper analyses the typology of capitalism in Croatia. The Croatian form of capitalism is specific, in form and origin, with links between the pre-independence and post-independence periods, implying that capitalism has gradually evolved – from the political during the eighties towards current clientelistic capitalism. The manufacturing focus aims to facilitate the analysis of institutional, political and economic changes over the past forty years, emphasising the implications of instituti...

  2. A Study of Interactions Between Thrust and Strike-slip Faults

    Directory of Open Access Journals (Sweden)

    Jeng-Cheng Wang

    2013-01-01

    Full Text Available A 3-D finite difference method is applied in this study to investigate a spontaneous rupture within a fault system which includes a primary thrust fault and two strike-slip sub-faults. With the occurrence of a rupture on a fault, the rupture condition follows Coulomb¡¦s friction law wherein the stress-slip obeys the slip-weakening fracture criteria. To overcome the geometrical complexity of such a system, a finite difference method is encoded in two different coordinate systems; then, the calculated displacements are connected between the two systems using a 2-D interpolation technique. The rupture is initiated at the center of the main fault under the compression of regional tectonic stresses and then propagates to the boundaries whereby the main fault rupture triggers two strike-slip sub-faults. Simulation results suggest that the triggering of two sub-faults is attributed to two primary factors, regional tectonic stresses and the relative distances between the two sub-faults and the main fault.

  3. Unscented Kalman Filter-Trained Neural Networks for Slip Model Prediction

    Science.gov (United States)

    Li, Zhencai; Wang, Yang; Liu, Zhen

    2016-01-01

    The purpose of this work is to investigate the accurate trajectory tracking control of a wheeled mobile robot (WMR) based on the slip model prediction. Generally, a nonholonomic WMR may increase the slippage risk, when traveling on outdoor unstructured terrain (such as longitudinal and lateral slippage of wheels). In order to control a WMR stably and accurately under the effect of slippage, an unscented Kalman filter and neural networks (NNs) are applied to estimate the slip model in real time. This method exploits the model approximating capabilities of nonlinear state–space NN, and the unscented Kalman filter is used to train NN’s weights online. The slip parameters can be estimated and used to predict the time series of deviation velocity, which can be used to compensate control inputs of a WMR. The results of numerical simulation show that the desired trajectory tracking control can be performed by predicting the nonlinear slip model. PMID:27467703

  4. SlipStream: automated provisioning and continuous deployment in the cloud

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Cloud technology is now everywhere. Beyond the hype, it provides a real opportunity to improve the engineering of software systems. Lately the DevOps movement has also gain momentum, which take an agile approach at bringing developers and system administrators closer together to better engineer software systems. In this context, this presentation focuses on new tools for exploiting cloud services (private and public) in order to create a continuous flow between software commits and fully deployed and configured software systems, automatically and on-demand. To illustrate this, we present SlipStream and StratusLab. SlipStream is a new product developed by SixSq, able to create virtual machines and orchestrate multi-machine deployments.  SlipStream started from an idea developed in the context of the ETICS project, led by CERN. StratusLab is an open-source IaaS distribution, able to create public and private clouds. This presentation will also describe a case study where SlipStream dep...

  5. Spatial Comparisons of Tremor and Slow Slip as a Constraint on Fault Strength in the Northern Cascadia Subduction Zone

    Science.gov (United States)

    Hall, K.; Schmidt, D. A.; Houston, H.

    2017-12-01

    We measure displacement vectors from about 50 or more PANGA 3-component GPS stations to analyze six large ETS events from 2007 - 2016 in northern Cascadia, and invert for slip on a realistic plate interface. Our previous results indicated that significant slip of up to 2 cm occurs 10 to 15 km up-dip of the western edge of tremor beneath the Olympic Peninsula. This far up-dip aseismic slip persists in several of the ETS events. We also find that this offset appears to vary along-strike with a greater offset beneath the Olympic Peninsula and up into the Strait of Juan de Fuca in comparison to lower Puget Sound. To explain this, we explore how properties (temperature and permeability) of the overlying structure may influence fault strength. In our conceptual model, the observation that slip inferred from GPS can extend updip of tremor suggests that updip of the observed edge of tremor, seismogenic patches that could produce tremor and low frequency earthquakes (LFEs) are too strong to fail from the relatively minor amount of far up-dip slow slip. This is consistent with the observation that, within the ETS zone, down-dip LFEs occur frequently, whereas up-dip LFEs occur only during the largest ETS events and are unaffected by tidal stresses until the later stages of an ETS event. This suggests that the up-dip seismogenic patches have a larger discrepancy between their strength and stress states, and therefore require larger stress perturbations (such as those from a propagating ETS slip pulse) to trigger seismic failure. We consider whether lateral variations in overlying structure may explain the along-strike variations in far up-dip aseismic slip. There is an abrupt change in lithology from the meta-sediments of the Olympic accretionary complex to the mafic basalts of the Crescent terrane. The juxtaposition of these different lithologies could potentially explain the along-strike variations in far up-dip aseismic slip. We propose to explore whether relative changes

  6. The Effects of Obesity and Age on Balance Recovery After Slipping

    OpenAIRE

    Allin, Leigh Jouett

    2014-01-01

    Falls due to slipping are a serious occupational concern. Slipping is estimated to cause 40-50% of all fall-related injuries. In 2011, falls resulted in 22% of injuries requiring days away from work. Epidemiological data indicates that older and obese adults experience more falls than young, non-obese individuals. An increasingly heavier and older workforce may be exacerbating the problem of slip-induced falls in the workplace. The purpose of this study was to examine the effects of obesity a...

  7. On the micromechanics of slip events in sheared, fluid-saturated fault gouge

    Science.gov (United States)

    Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul A.; Marone, Chris; Carmeliet, Jan

    2017-06-01

    We used a three-dimensional discrete element method coupled with computational fluid dynamics to study the poromechanical properties of dry and fluid-saturated granular fault gouge. The granular layer was sheared under dry conditions to establish a steady state condition of stick-slip dynamic failure, and then fluid was introduced to study its effect on subsequent failure events. The fluid-saturated case showed increased stick-slip recurrence time and larger slip events compared to the dry case. Particle motion induces fluid flow with local pressure variation, which in turn leads to high particle kinetic energy during slip due to increased drag forces from fluid on particles. The presence of fluid during the stick phase of loading promotes a more stable configuration evidenced by higher particle coordination number. Our coupled fluid-particle simulations provide grain-scale information that improves understanding of slip instabilities and illuminates details of phenomenological, macroscale observations.

  8. Complex evolution of transient slip derived from precise tremor locations in western Shikoku, Japan

    Science.gov (United States)

    Shelly, David R.; Beroza, Gregory C.; Ide, Satoshi

    2007-10-01

    Transient slip events, which occur more slowly than traditional earthquakes, are increasingly being recognized as important components of strain release on faults and may substantially impact the earthquake cycle. Surface-based geodetic instruments provide estimates of the overall slip distribution in larger transients but are unable to capture the detailed evolution of such slip, either in time or in space. Accompanying some of these slip transients is a relatively weak, extended duration seismic signal, known as nonvolcanic tremor, which has recently been shown to be generated by a sequence of shear failures occurring as part of the slip event. By precisely locating the tremor, we can track some features of slip evolution with unprecedented resolution. Here, we analyze two weeklong episodes of tremor and slow slip in western Shikoku, Japan. We find that these slip transients do not evolve in a smooth and steady fashion but contain numerous subevents of smaller size and shorter duration. In addition to along-strike migration rates of ˜10 km/d observed previously, much faster migration also occurs, usually in the slab dip direction, at rates of 25-150 km/h over distances of up to ˜20 km. We observe such migration episodes in both the updip and downdip directions. These episodes may be most common on certain portions of the plate boundary that generate strong tremor in intermittent bursts. The surrounding regions of the fault may slip more continuously, driving these stronger patches to repeated failures. Tremor activity has a strong tidal periodicity, possibly reflecting the modulation of slow slip velocity by tidal stresses.

  9. Influence of plastic slip localization on grain boundary stress fields and microcrack nucleation

    International Nuclear Information System (INIS)

    Sauzay, Maxime; Vor, Kokleang

    2013-01-01

    Slip localization is widely observed in metallic polycrystals after tensile deformation, cyclic deformation (persistent slip bands) or pre-irradiation followed by tensile deformation (channels). Such strong deformation localized in thin slip bands induces local stress concentrations in the quasi-elastic matrix around, at the intersections between slip bands and grain boundaries where microcracks are often observed. Since the work of Stroh, such stress fields have been modeled using the dislocation pile-up theory which leads to stress singularities similar to the LEFM ones. The Griffith criterion has then been widely applied, leading usually to strong underestimations of the macroscopic stress for microcrack nucleation. In fact, slip band thickness is finite: 50-1000 nm depending on material, temperature and loading conditions. Then, many slip planes are plastically activated through the thickness. Stress fields have probably been overestimated using the pile-up theory which assumes that all dislocations are located on the same atomic plane. To evaluate more realistic stress fields, crystalline finite element (FE) computations are carried out using microstructure inputs (slip band aspect ratio and spacing). Slip bands (low critical resolved shear stress) are embedded in an elastic matrix. The following results are obtained concerning grain boundary normal stress fields: - strong influence of slip band thickness close to the slip band corner, which is not accounted for by the pile-up theory. But far away, the thickness has a negligible effect and the predicted stress fields are close to the one predicted by the pile-up theory, - analytical formulae are deduced from the numerous FE computation results which allows the prediction of surface/bulk slips as well as grain boundary stress fields. Slip band plasticity parameters, slip band length and thickness, Schmid factor and remote stress are taken into account. The dependence with respect to the various parameters can

  10. Constraining slip rates and spacings for active normal faults

    Science.gov (United States)

    Cowie, Patience A.; Roberts, Gerald P.

    2001-12-01

    Numerous observations of extensional provinces indicate that neighbouring faults commonly slip at different rates and, moreover, may be active over different time intervals. These published observations include variations in slip rate measured along-strike of a fault array or fault zone, as well as significant across-strike differences in the timing and rates of movement on faults that have a similar orientation with respect to the regional stress field. Here we review published examples from the western USA, the North Sea, and central Greece, and present new data from the Italian Apennines that support the idea that such variations are systematic and thus to some extent predictable. The basis for the prediction is that: (1) the way in which a fault grows is fundamentally controlled by the ratio of maximum displacement to length, and (2) the regional strain rate must remain approximately constant through time. We show how data on fault lengths and displacements can be used to model the observed patterns of long-term slip rate where measured values are sparse. Specifically, we estimate the magnitude of spatial variation in slip rate along-strike and relate it to the across-strike spacing between active faults.

  11. 78 FR 55339 - Regulatory Capital Rules: Regulatory Capital, Implementation of Basel III, Capital Adequacy...

    Science.gov (United States)

    2013-09-10

    ... countercyclical capital buffer was designed to take into account the macro-financial environment in which large... ability to raise capital to meet the increased minimum requirements in the current environment and upon...

  12. Social Capital and Economic Integration of Migrants in Urban China.

    Science.gov (United States)

    Lu, Yao; Ruan, Danching; Lai, Gina

    2013-07-01

    Based on data from a 2005 survey conducted in Shanghai, China, this research examines the role of social capital in income inequality between rural migrants and urbanites. We find strong income return on social capital, in particular on social capital from strong ties. We also observe a great disparity in social capital possession between rural migrants and urban local residents. Although social capital from strong ties seems to be more important for rural migrants than for urbanites, local ties and high-status ties do not seem to benefit rural migrants. Hence, migrants not only suffer severe social capital deficits but also capital return deficits. Given the strong income returns on social capital and the substantial differences in access to and return on social capital between migrants and urban residents, social capital is consequently found to explain a large part of the income inequality between the two groups. Overall, our findings reveal macro-structural effects on the role of social capital in labor market stratification. In China, the lack of formal labor market mechanisms continues to create both a strong need for and opportunities for economic actions to be organized around informal channels via social relations. Yet, the long-standing institutional exclusion of migrants caused by the household registration system has resulted in pervasive social exclusion and discrimination which have substantially limited rural migrants' accumulation and mobilization of social capital. Under these conditions, social capital reinforces the economic inequality between migrants and urban residents in China. Such empirical evidence adds to our understanding of the role of social capital in the economic integration of migrants and in shaping intergroup inequality in general.

  13. Slip experiment on a flat bottom cylindrical shell tank model; Hirazoko ento choso mokei no katsudo jikken

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, T.; Mentani, Y.; Komori, H.; Yoshihara, T. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1998-12-20

    Although large tank slip, as observed in Alaska in 1964, was not reported in the Hyogo Nanbu Earthquake, tank slip becomes a major concern in seismic engineering. In the case of a non-uplifting tank, ifs slip behavior can be accurately described by the simple analytical model which consists of a single degree of freedom on a potential sliding mass (SDOF slip model). Employing friction force during slip, the governing equations of the SDOF slip model are formulated as a discontinuous linear vibration system. From the analogies between the SDOF slip model and the tank, the physical quantities which correspond to the SDOF slip model are determined in accordance with the values which are specified by the seismic design code for the tank. Comparison of the experimental results of the model tank slip with the analytical results based on the SDOF slip model corroborates ifs applicability to the tank slip with sufficient accuracy. (author)

  14. Areas prone to slow slip events impede earthquake rupture propagation and promote afterslip

    Science.gov (United States)

    Rolandone, Frederique; Nocquet, Jean-Mathieu; Mothes, Patricia A.; Jarrin, Paul; Vallée, Martin; Cubas, Nadaya; Hernandez, Stephen; Plain, Morgan; Vaca, Sandro; Font, Yvonne

    2018-01-01

    At subduction zones, transient aseismic slip occurs either as afterslip following a large earthquake or as episodic slow slip events during the interseismic period. Afterslip and slow slip events are usually considered as distinct processes occurring on separate fault areas governed by different frictional properties. Continuous GPS (Global Positioning System) measurements following the 2016 Mw (moment magnitude) 7.8 Ecuador earthquake reveal that large and rapid afterslip developed at discrete areas of the megathrust that had previously hosted slow slip events. Regardless of whether they were locked or not before the earthquake, these areas appear to persistently release stress by aseismic slip throughout the earthquake cycle and outline the seismic rupture, an observation potentially leading to a better anticipation of future large earthquakes. PMID:29404404

  15. Investigation of Floor Surface Finishes for Optimal Slip Resistance Performance

    Directory of Open Access Journals (Sweden)

    In-Ju Kim

    2018-03-01

    Full Text Available Background: Increasing the slip resistance of floor surfaces would be desirable, but there is a lack of evidence on whether traction properties are linearly correlated with the topographic features of the floor surfaces or what scales of surface roughness are required to effectively control the slipperiness of floors. Objective: This study expands on earlier findings on the effects of floor surface finishes against slip resistance performance and determines the operative ranges of floor surface roughness for optimal slip resistance controls under different risk levels of walking environments. Methods: Dynamic friction tests were conducted among three shoes and nine floor specimens under wet and oily environments and compared with a soapy environment. Results: The test results showed the significant effects of floor surface roughness on slip resistance performance against all the lubricated environments. Compared with the floor-type effect, the shoe-type effect on slip resistance performance was insignificant against the highly polluted environments. The study outcomes also indicated that the oily environment required rougher surface finishes than the wet and soapy ones in their lower boundary ranges of floor surface roughness. Conclusion: The results of this study with previous findings confirm that floor surface finishes require different levels of surface coarseness for different types of environmental conditions to effectively manage slippery walking environments. Collected data on operative ranges of floor surface roughness seem to be a valuable tool to develop practical design information and standards for floor surface finishes to efficiently prevent pedestrian fall incidents. Keywords: floor surface finishes, operational levels of floor surface roughness, slip resistance, wet, soapy and oily environments

  16. Public Debts and Private Assets: Explaining Capital Flight from Sub-Saharan African Countries

    OpenAIRE

    Léonce Ndikumana; James K. Boyce

    2002-01-01

    We investigate the determinants of capital flight from 30 sub-Saharan African countries, including 24 countries classified as severely indebted low-income countries, for the period 1970-1996. The econometric analysis reveals that external borrowing is positively and significantly related to capital flight, suggesting that to a large extent capital flight is debt-fueled. We estimate that for every dollar of external borrowing in the region, roughly 80 cents flowed back as capital flight in the...

  17. A Comparison of Traditional and Newly Emerging Forms of Cooperative Capitalization

    OpenAIRE

    Barton, David G.

    2004-01-01

    This paper compares the traditional forms of capitalization used by American co-ops to newly emerging forms. It is based on an in-depth review of several case co-ops. A broad framework is provided that may be beneficial in more extensive studies of capitalization practices of cooperatives and similar organizations. It is divided into three parts. Part One outlines the alternative capitalization forms being used by cooperatives and their antecedents, where conversions to other structures and f...

  18. Determinants of Capital Structure in Non-Financial Companies

    OpenAIRE

    Kühnhausen, Fabian; Stieber, Harald W.

    2014-01-01

    In this paper, we evaluate firm-, industry- and country-specific factors determining a firm's capital structure. The empirical validity of several capital structure theories has been ambiguous so far. We shed light on the main drivers of leverage and depict differences in industry and country characteristics. Using a short panel data set with a large cross-section, we are able to show that firm size, industry leverage, industry growth and tax shield positively affect leverage ratios, while pr...

  19. Documentation of programs that compute 1) static tilts for a spatially variable slip distribution, and 2) quasi-static tilts produced by an expanding dislocation loop with a spatially variable slip distribution

    Science.gov (United States)

    McHugh, Stuart

    1976-01-01

    The material in this report is concerned with the effects of a vertically oriented rectangular dislocation loop on the tilts observed at the free surface of an elastic half-space. Part I examines the effect of a spatially variable static strike-slip distribution across the slip surface. The tilt components as a function of distance parallel, or perpendicular, to the strike of the slip surface are displayed for different slip-versus-distance profiles. Part II examines the effect of spatially and temporally variable slip distributions across the dislocation loop on the quasi-static tilts at the free surface of an elastic half space. The model discussed in part II may be used to generate theoretical tilt versus time curves produced by creep events.

  20. Thermophoretic diffusion and nonlinear radiative heat transfer due to a contracting cylinder in a nanofluid with generalized slip condition

    Directory of Open Access Journals (Sweden)

    Z. Abbas

    Full Text Available An analysis is carried out to study the generalized slip condition and MHD flow of a nanofluid due to a contracting cylinder in the presence of non-linear radiative heat transfer using Buongiorno’s model. The Navier-Stokes along with energy and nanoparticle concentration equations is transformed to highly nonlinear ordinary differential equations using similarity transformations. These similar differential equations are then solved numerically by employing a shooting technique with Runge–Kutta–Fehlberg method. Dual solutions exist for a particular range of the unsteadiness parameter. The physical influence of the several important fluid parameters on the flow velocity, temperature and nanoparticle volume fraction is discussed and shown through graphs and table in detail. The present study indicates that as increase of Brownian motion parameter and slip velocity is to decrease the nanoparticle volume fraction. Keywords: Nanofluid, Contracting cylinder, Nonlinear thermal radiation, Generalized slip condition, Numerical solution

  1. Slip Control of Electric Vehicle Based on Tire-Road Friction Coefficient Estimation

    Directory of Open Access Journals (Sweden)

    Gaojian Cui

    2017-01-01

    Full Text Available The real-time change of tire-road friction coefficient is one of the important factors that influence vehicle safety performance. Besides, the vehicle wheels’ locking up has become an important issue. In order to solve these problems, this paper comes up with a novel slip control of electric vehicle (EV based on tire-road friction coefficient estimation. First and foremost, a novel method is proposed to estimate the tire-road friction coefficient, and then the reference slip ratio is determined based on the estimation results. Finally, with the reference slip ratio, a slip control based on model predictive control (MPC is designed to prevent the vehicle wheels from locking up. In this regard, the proposed controller guarantees the optimal braking torque on each wheel by individually controlling the slip ratio of each tire within the stable zone. Theoretical analyses and simulation show that the proposed controller is effective for better braking performance.

  2. Near-trench slip potential of megaquakes evaluated from fault properties and conditions

    Science.gov (United States)

    Hirono, Tetsuro; Tsuda, Kenichi; Tanikawa, Wataru; Ampuero, Jean-Paul; Shibazaki, Bunichiro; Kinoshita, Masataka; Mori, James J.

    2016-01-01

    Near-trench slip during large megathrust earthquakes (megaquakes) is an important factor in the generation of destructive tsunamis. We proposed a new approach to assessing the near-trench slip potential quantitatively by integrating laboratory-derived properties of fault materials and simulations of fault weakening and rupture propagation. Although the permeability of the sandy Nankai Trough materials are higher than that of the clayey materials from the Japan Trench, dynamic weakening by thermally pressurized fluid is greater at the Nankai Trough owing to higher friction, although initially overpressured fluid at the Nankai Trough restrains the fault weakening. Dynamic rupture simulations reproduced the large slip near the trench observed in the 2011 Tohoku-oki earthquake and predicted the possibility of a large slip of over 30 m for the impending megaquake at the Nankai Trough. Our integrative approach is applicable globally to subduction zones as a novel tool for the prediction of extreme tsunami-producing near-trench slip. PMID:27321861

  3. Large-magnitude Dextral Slip on the Wairarapa Fault, New Zealand

    Science.gov (United States)

    Rodgers, D. W.; Little, T.

    2004-12-01

    Dextral slip associated with an 1855 Ms 8.0+ event on the Wairarapa fault near Wellington, New Zealand was reported to be 12+/-1 m along a rupture length of at least 148km (Grapes, 1999), one of the largest single-event strike-slip offsets documented worldwide. Initial results from a new study involving detailed neotectonic mapping and microtopographic surveys of offset landforms (including many beheaded, inactive streams) strongly suggest that dextral slip was as much as 50% greater than previously measured. 1855 surface ruptures were mapped with certainty where a linear scarp characterized by steep slopes (30-90°) and exposed alluvium cuts across active or inactive stream channels. The fifteen individual strands comprising the Wairarapa fault zone that we have mapped to date are 1200+/-700 m long and typically left-stepping. Slip in the stepover zones between these strands is distributed amongst two or more ruptures and intervening anticlines, a situation that causes along-strike variations in slip and which locally complicates the interpretation of 1855 displacement. We focused on seven of the best-preserved sites where low-discharge streams are disrupted by the fault zone, including five that had been previously attributed by Grapes (1999) to coseismic slip during the 1855 earthquake. One of these (Pigeon Bush) includes two sequentially displaced, now beheaded linear stream channels, oriented perpendicular to the fault scarp, that preserve distinct offsets with respect to a single deeply incised, originally contiguous gorge on the opposite side of the fault. To quantify the minimum fault displacements at each site, we made 1:500 scale topographic maps employing n = 2,000-10,000 points collected with GPS and laser instrumentation. Measured dextral slip values, here attributed to the 1855 earthquake, include 16.4+/-1.0m (Hinaburn), 12.9+/-2.0m (Cross Creek), 17.2+/-2.5m (Lake Meadows), 18.7+/-1.0m (Pigeon Bush), 13.0+/-1.5m (Pigeon Bush 2), 15.1+/-1.0m (Pigeon

  4. Inefficient postural responses to unexpected slips during walking in older adults.

    Science.gov (United States)

    Tang, P F; Woollacott, M H

    1998-11-01

    Slips account for a high percentage of falls and subsequent injuries in community-dwelling older adults but not in young adults. This phenomenon suggests that although active and healthy older adults preserve a mobility level comparable to that of young adults, these older adults may have difficulty generating efficient reactive postural responses when they slip. This study tested the hypothesis that active and healthy older adults use a less effective reactive balance strategy than young adults when experiencing an unexpected forward slip occurring at heel strike during walking. This less effective balance strategy would be manifested by slower and smaller postural responses, altered temporal and spatial organization of the postural responses, and greater upper trunk instability after the slip. Thirty-three young adults (age range=19-34 yrs, mean=25+/-4 yrs) and 32 community-dwelling older adults (age range=70-87 yrs, mean=74+/-14 yrs) participated. Subjects walked across a movable forceplate which simulated a forward slip at heel strike. Surface electromyography was recorded from bilateral leg, thigh, hip, and trunk muscles. Kinematic data were collected from the right (perturbed) side of the body. Although the predominant postural muscles and the activation sequence of these muscles were similar between the two age groups, the postural responses of older adults were of longer onset latencies, smaller magnitudes, and longer burst durations compared to young adults. Older adults also showed a longer coactivation duration for the ankle, knee, and trunk agonist/antagonist pairs on the perturbed side and for the knee agonist/antagonist pair on the nonperturbed side. Behaviorally, older adults became less stable after the slips. This was manifested by a higher incidence of being tripped (21 trials in older vs 5 trials in young adults) and a greater trunk hyperextension with respect to young adults. Large arm elevation was frequently used by older adults to assist in

  5. The role of bed-parallel slip in the development of complex normal fault zones

    Science.gov (United States)

    Delogkos, Efstratios; Childs, Conrad; Manzocchi, Tom; Walsh, John J.; Pavlides, Spyros

    2017-04-01

    Normal faults exposed in Kardia lignite mine, Ptolemais Basin, NW Greece formed at the same time as bed-parallel slip-surfaces, so that while the normal faults grew they were intermittently offset by bed-parallel slip. Following offset by a bed-parallel slip-surface, further fault growth is accommodated by reactivation on one or both of the offset fault segments. Where one fault is reactivated the site of bed-parallel slip is a bypassed asperity. Where both faults are reactivated, they propagate past each other to form a volume between overlapping fault segments that displays many of the characteristics of relay zones, including elevated strains and transfer of displacement between segments. Unlike conventional relay zones, however, these structures contain either a repeated or a missing section of stratigraphy which has a thickness equal to the throw of the fault at the time of the bed-parallel slip event, and the displacement profiles along the relay-bounding fault segments have discrete steps at their intersections with bed-parallel slip-surfaces. With further increase in displacement, the overlapping fault segments connect to form a fault-bound lens. Conventional relay zones form during initial fault propagation, but with coeval bed-parallel slip, relay-like structures can form later in the growth of a fault. Geometrical restoration of cross-sections through selected faults shows that repeated bed-parallel slip events during fault growth can lead to complex internal fault zone structure that masks its origin. Bed-parallel slip, in this case, is attributed to flexural-slip arising from hanging-wall rollover associated with a basin-bounding fault outside the study area.

  6. Experimental tests on slip factor in friction joints: comparison between European and American Standards

    Directory of Open Access Journals (Sweden)

    Emanuele Maiorana

    2018-01-01

    Full Text Available Friction joints are used in steel structures submitted to cyclic loading such as, for example, in steel and composite bridges, in overhead cranes, and in equipment subjected to fatigue. Slip-critical steel joints with preloaded bolts are characterized by high rigidity and good performance against fatigue and vibrational phenomena. The most important parameter for the calculation of the bolt number in a friction connection is the slip factor, depending on the treatment of the plane surfaces inside the joint package. The paper focuses on the slip factor values reported in European and North American Specifications, and in literature references. The differences in experimental methods of slip test and evaluation of them for the mentioned standards are discussed. The results from laboratory tests regarding the assessment of the slip factor related to only sandblasted and sandblasted and coated surfaces are reported. Experimental data are compared with other results from the literature review to find the most influent parameters that control the slip factor in friction joint and differences between the slip tests procedures

  7. Slip estimation methods for proprioceptive terrain classification using tracked mobile robots

    CSIR Research Space (South Africa)

    Masha, Ditebogo F

    2017-11-01

    Full Text Available Recent work has shown that proprioceptive measurements such as terrain slip can be used for terrain classification. This paper investigates the suitability of four simple slip estimation methods for differentiating between indoor and outdoor terrain...

  8. Wheel Slip Control of Vehicle ABS Using Piezoactuator-Based Valve System

    Directory of Open Access Journals (Sweden)

    Juncheol Jeon

    2014-04-01

    Full Text Available This paper presents a novel piezoactuator-based valve for vehicle ABS. The piezoactuator located in one side of a rigid beam makes a displacement required to control the pressure at a flapper-nozzle of the pneumatic valve. In order to obtain the wide control range of the pressure, a pressure modulator comprised of dual-type cylinder and piston is proposed. The governing equation of the piezovalve system which consists of the proposed piezoactuator-based valve and the pressure modulator is obtained. The longitudinal vehicle dynamics and the wheel slip condition are then formulated. In order to evaluate the performance of the proposed piezovalve system from the viewpoint of the vehicle ABS, a sliding mode controller is designed for wheel slip control. The tracking control performances for the desired wheel slip rate are evaluated and the braking performances in terms of braking distance are then presented on different road conditions (dry asphalt, wet asphalt, and wet jennite. It is clearly shown that the desired wheel slip rate is well achieved and the braking distance and braking time can be significantly reduced by using the proposed piezovalve system associated with the slip rate controller.

  9. Adjoint-consistent formulations of slip models for coupled electroosmotic flow systems

    KAUST Repository

    Garg, Vikram V

    2014-09-27

    Background Models based on the Helmholtz `slip\\' approximation are often used for the simulation of electroosmotic flows. The objectives of this paper are to construct adjoint-consistent formulations of such models, and to develop adjoint-based numerical tools for adaptive mesh refinement and parameter sensitivity analysis. Methods We show that the direct formulation of the `slip\\' model is adjoint inconsistent, and leads to an ill-posed adjoint problem. We propose a modified formulation of the coupled `slip\\' model, which is shown to be well-posed, and therefore automatically adjoint-consistent. Results Numerical examples are presented to illustrate the computation and use of the adjoint solution in two-dimensional microfluidics problems. Conclusions An adjoint-consistent formulation for Helmholtz `slip\\' models of electroosmotic flows has been proposed. This formulation provides adjoint solutions that can be reliably used for mesh refinement and sensitivity analysis.

  10. Characterisation of the wall-slip during extrusion of heavy-clay products

    Science.gov (United States)

    Kocserha, I.; Gömze, A. L.; Kulkov, S.; Kalatur, E.; Buyakova, S. P.; Géber, R.; Buzimov, A. Y.

    2017-01-01

    During extrusion through the extrusion die, heavy-clay compounds are usually show plug flow with extensive slip at the wall of the die. In this study, the viscosity and the thickness of the slip layer were investigated. For the examination a brick-clay from Malyi (Hungary) deposit was applied as a raw material. The clay was characterised by XRPD, BET, SEM and granulometry. As the slip layer consists of suspension of the fine clay fraction so the clay minerals content of the clay (dviscosity of suspension with different water content was measured by means of rotational viscosimeter. The thickness of the slip layer was calculated from the measured viscosity and other data obtained from an earlier study with capillary rheometer. The calculated thickness value showed a tendency to reach a limit value by increasing the extrusion speed.

  11. Predicting geometry of slip surfaces beneath landslides by fuzzy theory. Fuzzy riron wo riyoshita suberimen yosoku

    Energy Technology Data Exchange (ETDEWEB)

    Ono, K [Mie Univ., Mie (Japan). Faculty of Biological and Resources

    1991-12-01

    In case a landslide occurs on a slope, grasping the area of influence (location and shape of the slip surface) is required to take a countermeasure against landslides. This paper describes a method developed by the author for predicting a slip surface by utilizing fuzzy theory. The method predicts a slip surface from observations on ground surface displacement vectors, and the validity of the method has been verified through slip experiments conducted on slopes with a centrifugal model experiment device. The developed method for predicting the location of a slip surface well matches the experiment results, indicating the validity of the method. It has been found that the difference between the predicted and observed locations of a slip surface mainly is due to the error of the prediction in the starting and ending locations of the slip surface. It is also pointed out that, in order to improve the prediction of the shape of a slip surface, the observation density must be increased at the location where the shape of the slip surface strongly varies, since the direction of the slip surface is determined by the direction of the ground surface displacement vectors. 4 refs., 7 figs.

  12. Micromechanics and statistics of slipping events in a granular seismic fault model

    Energy Technology Data Exchange (ETDEWEB)

    Arcangelis, L de [Department of Information Engineering and CNISM, Second University of Naples, Aversa (Italy); Ciamarra, M Pica [CNR-SPIN, Dipartimento di Scienze Fisiche, Universita di Napoli Federico II (Italy); Lippiello, E; Godano, C, E-mail: dearcangelis@na.infn.it [Department of Environmental Sciences and CNISM, Second University of Naples, Caserta (Italy)

    2011-09-15

    The stick-slip is investigated in a seismic fault model made of a confined granular system under shear stress via three dimensional Molecular Dynamics simulations. We study the statistics of slipping events and, in particular, the dependence of the distribution on model parameters. The distribution consistently exhibits two regimes: an initial power law and a bump at large slips. The initial power law decay is in agreement with the the Gutenberg-Richter law characterizing real seismic occurrence. The exponent of the initial regime is quite independent of model parameters and its value is in agreement with experimental results. Conversely, the position of the bump is solely controlled by the ratio of the drive elastic constant and the system size. Large slips also become less probable in absence of fault gouge and tend to disappear for stiff drives. A two-time force-force correlation function, and a susceptibility related to the system response to pressure changes, characterize the micromechanics of slipping events. The correlation function unveils the micromechanical changes occurring both during microslips and slips. The mechanical susceptibility encodes the magnitude of the incoming microslip. Numerical results for the cellular-automaton version of the spring block model confirm the parameter dependence observed for size distribution in the granular model.

  13. Measuring Capital

    OpenAIRE

    W. Erwin Diewert

    2003-01-01

    The paper revisits Harper, Berndt and Wood (1989) and calculates Canadian reproducible capital services aggregates under alternative assumptions about the form of depreciation, the opportunity cost of capital and the treatment of capital gains. Five different models of depreciation are considered: (1) one hoss shay; (2) straight line depreciation; (3) declining balance or geometric depreciation; (4) linearly declining efficiency profiles and (5) linearly increasing maintenance profiles. The l...

  14. Electrical Potentials Observed During Frictional Stick-Slip - A Semiconductor Mechanism

    Science.gov (United States)

    Leeman, J.; Scuderi, M.; Marone, C.; Saffer, D. M.

    2013-12-01

    Electromagnetic phenomena are commonly reported during and after large earthquakes. Various lines of evidence including charring of plant roots, magnetic remnant signatures in pseudotachylite, and visible earthquake lights indicate a strong electrical potential separation during co-seismic rupture. Suggested explanations have included triboelectricity, piezoelectricity, and streaming potentials. The 'semiconductor effect', or migration of electron holes, has been proposed as an alternative explanation and studied extensively in solids. We present evidence of a similar migration effect in a granular material that exhibits repeated frictional stick-slip events under a variety of conditions. Soda-lime glass beads were sheared in a double-direct shear configuration in a biaxial loading frame. Glass beads exhibit consistent, repetitive stick-slip and rate/state friction effects that are similar to rock. Layers of 5 mm thickness were sheared under a constant normal load of 4MPa, at load point velocities of 1, 30, and 100 μm/s. This was done for mono-disperse particle size distributions of 100-150 μm and 420-500 μm. Tests were conducted at room humidity, at 100% humidity, and under submerged conditions. During shearing, the electrical potential of the surface was monitored relative to the system ground with a non-contact electrostatic volt meter (ESVM) manufactured by Trek Incorporated. During stick-slip events, we observe electrical potential anomalies that appear to be related to failure of force chains supporting the shear load. Two distinct types of behavior are delineated by the attainment of steady state frictional sliding. In the pre-steady state phase, as shear stress is increasing, layers are observed to charge during stick-slip and the potential of the entire system rises. When shear stress rises to the level of steady state frictional sliding, the system begins to discharge, with superimposed anomalies characterized by potential drops of several volts that

  15. Stress and slip partitioning during oblique rifting: comparison between data from the Main Ethiopian Rift and laboratory experiments

    Science.gov (United States)

    Corti, G.; Philippon, M.; Sani, F.; Keir, D.

    2012-04-01

    Oblique rifting in the central and northern Main Ethiopian Rift (MER) has resulted in a complex structural pattern characterized by two differently oriented fault systems: a set of NE-SW-trending boundary faults and a system of roughly NNE-SSW-oriented fault swarms affecting the rift floor (Wonji faults). Boundary faults formed oblique to the regional extension vector, likely as a result of the oblique reactivation of a pre-existing deep-seated rheological anisotropy, whereas internal Wonji faults developed sub-orthogonal to the stretching direction. Previous works have successfully reconciled this rift architecture and fault distribution with the long-term plate kinematics; however, at a more local scale, fault-slip and earthquake data reveal significant variations in the orientation the minimum principal stress and related fault-slip direction across the rift valley. Whereas fault measurements indicate a roughly N95°E extension on the axial Wonji faults, a N105°E to N110°E directed minimum principal stress is observed along boundary faults. Both fault-slip data and analysis of seismicity indicate a roughly pure dip-slip motion on the boundary faults, despite their orientation (oblique to the regional extension vector) should result in an oblique displacement. To shed light on the process driving the variability of data derived from fault-slip (and seismicity) analysis we present crustal-scale analogue models of oblique rifting, deformed in a large-capacity centrifuge by using materials and boundary conditions described in several previous modeling works. As in these previous works, the experiments show the diachronous activation of two fault systems, boundary and internal, whose pattern strikingly resemble that observed in previous lithospheric-scale modeling, as well as that described in the MER. Internal faults arrange in two different, en-echelon segments connected by a transfer zone where strike-slip displacement dominates. Whereas internal faults develop

  16. Strike-Slip Fault Deformation and Its Control in Hydrocarbon Trapping in Ketaling Area, Jambi Subbasin, Indonesia

    Science.gov (United States)

    Ramadhan, Aldis; Badai Samudra, Alexis; Jaenudin; Puji Lestari, Enik; Saputro, Julian; Sugiono; Hirosiadi, Yosi; Amrullah, Indi

    2018-03-01

    Geologically, Ketaling area consists of a local high considered as flexure margin of Tempino-Kenali Asam Deep in west part and graben in east part also known as East Ketaling Deep. Numerous proven plays were established in Ketaling area with reservoir in early Miocene carbonate and middle Miocene sand. This area underwent several major deformations. Faults are developed widely, yet their geometrical features and mechanisms of formation remained so far indistinct, which limited exploration activities. With new three-dimensional seismic data acquired in 2014, this area evidently interpreted as having strike-slip mechanism. The objective of this study is to examine characteristic of strike slip fault and its affect to hydrocarbon trapping in Ketaling Area. Structural pattern and characteristic of strike slip fault deformation was examined with integration of normal seismic with variance seismic attribute analysis and the mapping of Syn-rift to Post-rift horizon. Seismic flattening on 2D seismic cross section with NW-SE direction is done to see the structural pattern related to horst (paleohigh) and graben. Typical flower structure, branching strike-slip fault system and normal fault in synrift sediment clearly showed in section. An echelon pattern identified from map view as the result of strike slip mechanism. Detail structural geology analysis show the normal fault development which has main border fault in the southern of Ketaling area dipping to the Southeast-East with NE-SW lineament. These faults related to rift system in Ketaling area. NW-SE folds with reactive NE-SW fault which act as hydrocarbon trapping in the shallow zone. This polyphase tectonic formed local graben, horst and inverted structure developed a good kitchen area (graben) and traps (horst, inverted structure). Subsequently, hydrocarbon accumulation potentials such as basement fractures, inverted syn-rift deposit and shallow zone are very interesting to explore in this area.

  17. Leakage flow-induced vibration of an unconstricted tube-in-tube slip joint

    International Nuclear Information System (INIS)

    Mulcahy, T.M.

    1986-12-01

    The conditions are given for which the more flexible of two cantilevered, telescoping tubes conveying fluid can be self-excited by flow leaking from an unconstricted slip joint. Also, a physical explanation of the excitation mechanism is discussed, and a design rule to avoid the mechanism is presented. In addition, the results for the unconstricted slip joint are shown to be similar to those for slip joints having annulus constrictions at very short engagement lengths

  18. Self-similar slip distributions on irregular shaped faults

    Science.gov (United States)

    Herrero, A.; Murphy, S.

    2018-06-01

    We propose a strategy to place a self-similar slip distribution on a complex fault surface that is represented by an unstructured mesh. This is possible by applying a strategy based on the composite source model where a hierarchical set of asperities, each with its own slip function which is dependent on the distance from the asperity centre. Central to this technique is the efficient, accurate computation of distance between two points on the fault surface. This is known as the geodetic distance problem. We propose a method to compute the distance across complex non-planar surfaces based on a corollary of the Huygens' principle. The difference between this method compared to others sample-based algorithms which precede it is the use of a curved front at a local level to calculate the distance. This technique produces a highly accurate computation of the distance as the curvature of the front is linked to the distance from the source. Our local scheme is based on a sequence of two trilaterations, producing a robust algorithm which is highly precise. We test the strategy on a planar surface in order to assess its ability to keep the self-similarity properties of a slip distribution. We also present a synthetic self-similar slip distribution on a real slab topography for a M8.5 event. This method for computing distance may be extended to the estimation of first arrival times in both complex 3D surfaces or 3D volumes.

  19. Strain hardening by dynamic slip band refinement in a high-Mn lightweight steel

    International Nuclear Information System (INIS)

    Welsch, E.; Ponge, D.; Hafez Haghighat, S.M.; Sandlöbes, S.; Choi, P.; Herbig, M.; Zaefferer, S.; Raabe, D.

    2016-01-01

    The strain hardening mechanism of a high-Mn lightweight steel (Fe-30.4Mn-8Al-1.2C (wt%)) is investigated by electron channeling contrast imaging (ECCI) and transmission electron microscopy (TEM). The alloy is characterized by a constant high strain hardening rate accompanied by high strength and high ductility (ultimate tensile strength: 900 MPa, elongation to fracture: 68%). Deformation microstructures at different strain levels are studied in order to reveal and quantify the governing structural parameters at micro- and nanometer scales. As the material deforms mainly by planar dislocation slip causing the formation of slip bands, we quantitatively study the evolution of the slip band spacing during straining. The flow stress is calculated from the slip band spacing on the basis of the passing stress. The good agreement between the calculated values and the tensile test data shows dynamic slip band refinement as the main strain hardening mechanism, enabling the excellent mechanical properties. This novel strain hardening mechanism is based on the passing stress acting between co-planar slip bands in contrast to earlier attempts to explain the strain hardening in high-Mn lightweight steels that are based on grain subdivision by microbands. We discuss in detail the formation of the finely distributed slip bands and the gradual reduction of the spacing between them, leading to constantly high strain hardening. TEM investigations of the precipitation state in the as-quenched state show finely dispersed atomically ordered clusters (size < 2 nm). The influence of these zones on planar slip is discussed.

  20. Mixed linear-nonlinear fault slip inversion: Bayesian inference of model, weighting, and smoothing parameters

    Science.gov (United States)

    Fukuda, J.; Johnson, K. M.

    2009-12-01

    Studies utilizing inversions of geodetic data for the spatial distribution of coseismic slip on faults typically present the result as a single fault plane and slip distribution. Commonly the geometry of the fault plane is assumed to be known a priori and the data are inverted for slip. However, sometimes there is not strong a priori information on the geometry of the fault that produced the earthquake and the data is not always strong enough to completely resolve the fault geometry. We develop a method to solve for the full posterior probability distribution of fault slip and fault geometry parameters in a Bayesian framework using Monte Carlo methods. The slip inversion problem is particularly challenging because it often involves multiple data sets with unknown relative weights (e.g. InSAR, GPS), model parameters that are related linearly (slip) and nonlinearly (fault geometry) through the theoretical model to surface observations, prior information on model parameters, and a regularization prior to stabilize the inversion. We present the theoretical framework and solution method for a Bayesian inversion that can handle all of these aspects of the problem. The method handles the mixed linear/nonlinear nature of the problem through combination of both analytical least-squares solutions and Monte Carlo methods. We first illustrate and validate the inversion scheme using synthetic data sets. We then apply the method to inversion of geodetic data from the 2003 M6.6 San Simeon, California earthquake. We show that the uncertainty in strike and dip of the fault plane is over 20 degrees. We characterize the uncertainty in the slip estimate with a volume around the mean fault solution in which the slip most likely occurred. Slip likely occurred somewhere in a volume that extends 5-10 km in either direction normal to the fault plane. We implement slip inversions with both traditional, kinematic smoothing constraints on slip and a simple physical condition of uniform stress

  1. Valuable human capital: the aging health care worker.

    Science.gov (United States)

    Collins, Sandra K; Collins, Kevin S

    2006-01-01

    With the workforce growing older and the supply of younger workers diminishing, it is critical for health care managers to understand the factors necessary to capitalize on their vintage employees. Retaining this segment of the workforce has a multitude of benefits including the preservation of valuable intellectual capital, which is necessary to ensure that health care organizations maintain their competitive advantage in the consumer-driven market. Retaining the aging employee is possible if health care managers learn the motivators and training differences associated with this category of the workforce. These employees should be considered a valuable resource of human capital because without their extensive expertise, intense loyalty and work ethic, and superior customer service skills, health care organizations could suffer severe economic repercussions in the near future.

  2. 78 FR 62017 - Regulatory Capital Rules: Regulatory Capital, Implementation of Basel III, Capital Adequacy...

    Science.gov (United States)

    2013-10-11

    ... unlevel playing field between banking organizations and other financial services providers. For example, a... for banking organizations. The final rule consolidates three separate notices of proposed rulemaking... minimum capital requirement, a higher minimum tier 1 capital requirement, and, for banking organizations...

  3. 12 CFR 325.103 - Capital measures and capital category definitions.

    Science.gov (United States)

    2010-01-01

    ... STATEMENTS OF GENERAL POLICY CAPITAL MAINTENANCE Prompt Corrective Action § 325.103 Capital measures and... agreement, order, capital directive, or prompt corrective action directive issued by the FDIC pursuant to... CFR 28.15(b), or to comply with asset maintenance requirements pursuant to 12 CFR 28.20; or (B) The...

  4. Prediction of Seismic Slope Displacements by Dynamic Stick-Slip Analyses

    International Nuclear Information System (INIS)

    Ausilio, Ernesto; Costanzo, Antonio; Silvestri, Francesco; Tropeano, Giuseppe

    2008-01-01

    A good-working balance between simplicity and reliability in assessing seismic slope stability is represented by displacement-based methods, in which the effects of deformability and ductility can be either decoupled or coupled in the dynamic analyses. In this paper, a 1D lumped mass ''stick-slip'' model is developed, accounting for soil heterogeneity and non-linear behaviour, with a base sliding mechanism at a potential rupture surface. The results of the preliminary calibration show a good agreement with frequency-domain site response analysis in no-slip conditions. The comparison with rigid sliding block analyses and with the decoupled approach proves that the stick-slip procedure can result increasingly unconservative for soft soils and deep sliding depths

  5. A prospective study of floor surface, shoes, floor cleaning and slipping in US limited-service restaurant workers.

    Science.gov (United States)

    Verma, Santosh K; Chang, Wen Ruey; Courtney, Theodore K; Lombardi, David A; Huang, Yueng-Hsiang; Brennan, Melanye J; Mittleman, Murray A; Ware, James H; Perry, Melissa J

    2011-04-01

    Slips and falls are a leading cause of injury at work. Few studies, however, have systematically examined risk factors of slipping outside the laboratory environment. This study examined the association between floor surface characteristics, slip-resistant shoes, floor cleaning frequency and the risk of slipping in limited-service restaurant workers. 475 workers from 36 limited-service restaurants from three major chains in six states in the USA were recruited to participate in a prospective cohort study of workplace slipping. Kitchen floor surface roughness and coefficient of friction (COF) were measured in eight working areas and then averaged within each restaurant. The use of slip-resistant shoes was determined by examining the participant's shoes and noting the presence of a 'slip-resistant' marking on the sole. Restaurant managers reported the frequency of daily kitchen floor cleaning. Participants reported their slip experience and work hours weekly for up to 12 weeks. The survey materials were made available in three languages: English, Spanish and Portuguese. The associations between rate of slipping and risk factors were assessed using a multivariable negative binomial generalised estimating equation model. The mean of individual slipping rate varied among the restaurants from 0.02 to 2.49 slips per 40 work hours. After adjusting for age, gender, BMI, education, primary language, job tenure and restaurant chain, the use of slip-resistant shoes was associated with a 54% reduction in the reported rate of slipping (95% CI 37% to 64%), and the rate of slipping decreased by 21% (95% CI 5% to 34%) for each 0.1 increase in the mean kitchen COF. Increasing floor cleaning frequency was significantly associated with a decreasing rate of slipping when considered in isolation but not after statistical adjustment for other factors. These results provide support for the use of slip-resistant shoes and measures to increase COF as preventive interventions to reduce slips

  6. EVOLUTION OF THE ROMANIAN CAPITAL MARKET IN THE LAST FOUR YEARS

    Directory of Open Access Journals (Sweden)

    SORIN CLAUDIU RADU

    2012-10-01

    Full Text Available The effects of the great recession have also been felt in Romania and the domestic capital market, component of the European financial market, has suffered from the negative evolutions of the world’s economy, fallowing the downward trend of the external markets since the crisis started. Considering the economic situation as of 2008, the Romanian capital market was faced with a small number of transactions, a decreased stock capitalization and low level of credibility, massive diminishment of liquidities, capital withdrawal on the financial market and significant depreciation of stock exchange indicators. This paper aims at presenting the evolution of the capital market in Romania for the last four years, pinpointing several strategic directions that are meant to support the domestic stock exchange and place them in the European stock exchanges top.

  7. Buried shallow fault slip from the South Napa earthquake revealed by near-field geodesy.

    Science.gov (United States)

    Brooks, Benjamin A; Minson, Sarah E; Glennie, Craig L; Nevitt, Johanna M; Dawson, Tim; Rubin, Ron; Ericksen, Todd L; Lockner, David; Hudnut, Kenneth; Langenheim, Victoria; Lutz, Andrew; Mareschal, Maxime; Murray, Jessica; Schwartz, David; Zaccone, Dana

    2017-07-01

    Earthquake-related fault slip in the upper hundreds of meters of Earth's surface has remained largely unstudied because of challenges measuring deformation in the near field of a fault rupture. We analyze centimeter-scale accuracy mobile laser scanning (MLS) data of deformed vine rows within ±300 m of the principal surface expression of the M (magnitude) 6.0 2014 South Napa earthquake. Rather than assuming surface displacement equivalence to fault slip, we invert the near-field data with a model that allows for, but does not require, the fault to be buried below the surface. The inversion maps the position on a preexisting fault plane of a slip front that terminates ~3 to 25 m below the surface coseismically and within a few hours postseismically. The lack of surface-breaching fault slip is verified by two trenches. We estimate near-surface slip ranging from ~0.5 to 1.25 m. Surface displacement can underestimate fault slip by as much as 30%. This implies that similar biases could be present in short-term geologic slip rates used in seismic hazard analyses. Along strike and downdip, we find deficits in slip: The along-strike deficit is erased after ~1 month by afterslip. We find no evidence of off-fault deformation and conclude that the downdip shallow slip deficit for this event is likely an artifact. As near-field geodetic data rapidly proliferate and will become commonplace, we suggest that analyses of near-surface fault rupture should also use more sophisticated mechanical models and subsurface geomechanical tests.

  8. Buried shallow fault slip from the South Napa earthquake revealed by near-field geodesy

    Science.gov (United States)

    Brooks, Benjamin A.; Minson, Sarah E.; Glennie, Craig L.; Nevitt, Johanna M.; Dawson, Tim; Rubin, Ron; Ericksen, Todd L.; Lockner, David; Hudnut, Kenneth; Langenheim, Victoria; Lutz, Andrew; Mareschal, Maxime; Murray, Jessica; Schwartz, David; Zaccone, Dana

    2017-01-01

    Earthquake-related fault slip in the upper hundreds of meters of Earth’s surface has remained largely unstudied because of challenges measuring deformation in the near field of a fault rupture. We analyze centimeter-scale accuracy mobile laser scanning (MLS) data of deformed vine rows within ±300 m of the principal surface expression of the M (magnitude) 6.0 2014 South Napa earthquake. Rather than assuming surface displacement equivalence to fault slip, we invert the near-field data with a model that allows for, but does not require, the fault to be buried below the surface. The inversion maps the position on a preexisting fault plane of a slip front that terminates ~3 to 25 m below the surface coseismically and within a few hours postseismically. The lack of surface-breaching fault slip is verified by two trenches. We estimate near-surface slip ranging from ~0.5 to 1.25 m. Surface displacement can underestimate fault slip by as much as 30%. This implies that similar biases could be present in short-term geologic slip rates used in seismic hazard analyses. Along strike and downdip, we find deficits in slip: The along-strike deficit is erased after ~1 month by afterslip. We find no evidence of off-fault deformation and conclude that the downdip shallow slip deficit for this event is likely an artifact. As near-field geodetic data rapidly proliferate and will become commonplace, we suggest that analyses of near-surface fault rupture should also use more sophisticated mechanical models and subsurface geomechanical tests. PMID:28782026

  9. The Pro-Cyclical Impact of Basel III Regulatory Capital on Bank Capital Risk

    OpenAIRE

    Song, Guoxiang

    2014-01-01

    To raise the quality of regulatory capital, Basel III capital rules recognize unrealized gains and losses on all available-for-sale (AFS) securities in Common Equity Tier 1 Capital (CET1). However, by examining the correlations between U.S. GDP growth rate, interest rates and regulatory capital ratios computed using Basel III regulatory capital definition for six U.S. global systemically important banks (G-SIBs) since 2007, this chapter finds that Basel III regulatory capital will enhance the...

  10. Dislocation content of geometrically necessary boundaries aligned with slip planes in rolled aluminium

    DEFF Research Database (Denmark)

    Hong, Chuanshi; Huang, Xiaoxu; Winther, Grethe

    2013-01-01

    Previous studies have revealed that dislocation structures in metals with medium-to-high stacking fault energy, depend on the grain orientation and therefore on the slip systems. In the present work, the dislocations in eight slip-plane-aligned geometrically necessary boundaries (GNBs) in three...... expected active dominate. The dislocations predicted inactive are primarily attributed to dislocation reactions in the boundary. Two main types of dislocation networks in the boundaries were identified: (1) a hexagonal network of the three dislocations in the slip plane with which the boundary was aligned......; two of these come from the active slip systems, the third is attributed to dislocation reactions (2) a network of three dislocations from both of the active slip planes; two of these react to form Lomer locks. The results indicate a systematic boundary formation process for the GNBs. Redundant...

  11. Slip-stick excitation and travelling waves excite silo honking

    Science.gov (United States)

    Warburton, Katarzyna; Porte, Elze; Vriend, Nathalie

    2017-06-01

    Silo honking is the harmonic sound generated by the discharge of a silo filled with a granular material. In industrial storage silos, the acoustic emission during discharge of PET-particles forms a nuisance for the environment and may ultimately result in structural failure. This work investigates the phenomenon experimentally using a laboratory-scale silo, and successfully correlates the frequency of the emitted sound with the periodicity of the mechanical motion of the grains. The key driver is the slip-stick interaction between the wall and the particles, characterized as a wave moving upwards through the silo. A quantitative correlation is established for the first time between the frequency of the sound, measured with an electret microphone, and the slip-frequency, measured with a high-speed camera. In the lower regions of the tube, both the slip-stick motion and the honking sound disappear.

  12. Weak hydrogen bonding interactions influence slip system activity and compaction behavior of pharmaceutical powders.

    Science.gov (United States)

    Khomane, Kailas S; Bansal, Arvind K

    2013-12-01

    Markedly different mechanical behavior of powders of polymorphs, cocrystals, hydrate/anhydrate pairs, or structurally similar molecules has been attributed to the presence of active slip planes system in their crystal structures. Presence of slip planes in the crystal lattice allows easier slip under the applied compaction pressure. This allows greater plastic deformation of the powder and results into increased interparticulate bonding area and greater tensile strength of the compacts. Thus, based on this crystallographic feature, tableting performance of the active pharmaceutical ingredients can be predicted. Recently, we encountered a case where larger numbers of CH···O type interactions across the proposed slip planes hinder the slip and thus resist plastic deformation of the powder under the applied compaction pressure. Hence, attention must be given to these types of interactions while identifying slip planes by visualization method. Generally, slip planes are visualized as flat layers often strengthened by a two-dimensional hydrogen-bonding network within the layers or planes. No hydrogen bonding should exist between these layers to consider them as slip planes. Moreover, one should also check the presence of CH···O type interactions across these planes. Mercury software provides an option for visualization of these weak hydrogen bonding interactions. Hence, caution must be exercised while selecting appropriate solid form based on this crystallographic feature. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

  13. Effect of rotor rectifier on motor performance in slip recovery drives

    Energy Technology Data Exchange (ETDEWEB)

    Al Zahawi, B.A.T.; Jones, B.L.; Drury, W.

    1987-01-01

    The static Kramer system, comprising a slip-ring induction motor and a slip energy recovery circuit, is one of the simplest and most efficient forms of ac variable-speed drive. It is sometimes used to upgrade drives which had originally been designed for fixed speed operation, often with substantial energy savings. In such cases, it is important to know how the inclusion of a rectifier in the slip energy recovery circuit affects motor performance. A satisfactory model for the motor-rectifier combination is also needed to provide a sound basis for assessing alternative forms of recovery systems which aim to overcome the principal shortcomings of the drive, namely the magnitude and variability of its reactive power. Despite its simplicity, the Kramer drive presents a formidable analytical challenge. Rigorous analysis is particularly difficult and there is a need for a simpler form of analysis when calculating ratings and steady-state performance. The approach taken in this paper uses a transformer-type model for the motor, and largely analytical expressions for predicting torque, stator power, stator reactive power and rectifier output voltage. Motor resistances, diode characteristics, and the several possible rectifier overlap modes are included. It is shown that the rectifier has an adverse effect on stator reactive power, power factor, and peak torque, particularly at speeds well below synchronous, requiring some derating of motors designed for resistance control and also requiring additional power factor correction. While the analysis does not cater to variations caused by harmonics at some speeds, it does provide a quick, accurate method of predicting performance over most sections of the operating range. 12 refs., 11 figs.

  14. Entropy Stability and the No-Slip Wall Boundary Condition

    KAUST Repository

    Svä rd, Magnus; Carpenter, Mark H.; Parsani, Matteo

    2018-01-01

    We present an entropy stable numerical scheme subject to no-slip wall boundary conditions. To enforce entropy stability only the no-penetration boundary condition and a temperature condition are needed at a wall, and this leads to an L bound on the conservative variables. In this article, we take the next step and design a finite difference scheme that also bounds the velocity gradients. This necessitates the use of the full no-slip conditions.

  15. Entropy Stability and the No-Slip Wall Boundary Condition

    KAUST Repository

    Svärd, Magnus

    2018-01-18

    We present an entropy stable numerical scheme subject to no-slip wall boundary conditions. To enforce entropy stability only the no-penetration boundary condition and a temperature condition are needed at a wall, and this leads to an L bound on the conservative variables. In this article, we take the next step and design a finite difference scheme that also bounds the velocity gradients. This necessitates the use of the full no-slip conditions.

  16. Frictional processes in smectite-rich gouges sheared at slow to high slip rates

    Science.gov (United States)

    Aretusini, Stefano; Mittempergher, Silvia; Gualtieri, Alessandro; Di Toro, Giulio

    2015-04-01

    The slipping zones of shallow sections of megathrusts and of large landslides are often smectite-rich (e.g., montmorillonite type). Consequently, similar "frictional" processes operating at high slip rates (> 1 m/s) might be responsible of the large slips estimated in megathrust (50 m for the 2011 Tohoku Mw 9.1 earthquake) and measured in large landslides (500 m for the 1963 Vajont slide, Italy). At present, only rotary shear apparatuses can reproduce simultaneously the large slips and slip rates of these events. Noteworthy, the frictional processes proposed so far (thermal and thermochemical pressurization, etc.) remain rather obscure. Here we present preliminary results obtained with the ROtary Shear Apparatus (ROSA) installed at Padua University. Thirty-one experiments were performed at ambient conditions on pure end-members of (1) smectite-rich standard powders (STx-1b: ~68 wt% Ca-montmorillonite, ~30 wt% opal-CT and ~2 wt% quartz), (2) quartz powders (qtz) and (3) on 80:20 = Stx-1b:qtz mixtures. The gouges were sandwiched between two (1) hollow (25/15 mm external/internal diameter) or (2) solid (25 mm in diameter) stainless-steel made cylinders and confined by inner and outer Teflon rings (only outer for solid cylinders). Gouges were sheared at a normal stress of 5 MPa, slip rates V from 300 μm/s to 1.5 m/s and total slip of 3 m. The deformed gouges were investigated with quantitative (Rietveld method with internal standard) X-ray powder diffraction (XRPD) and Scanning Electron Microscopy (SEM). In the smectite-rich standard endmember, (1) for 300 μm/s ≤ V ≤ 0.1 m/s, initial friction coefficient (μi) was 0.6±0.05 whereas the steady-state friction coefficient (μss) was velocity and slip strengthening (μss 0.85±0.05), (2) for 0.1 m/s 0.8 m/s, velocity and slip weakening (μi = 0.7±0.1 and μss = 0.25±0.05). In the 80:20 Stx-1b:qtz mixtures, (1) for 300 μm/s ≤ V ≤ 0.1 m/s, μi ranged was 0.7±0.05 and increased with slip to μss = 0.77±0

  17. Surface slip during large Owens Valley earthquakes

    KAUST Repository

    Haddon, E. K.; Amos, C. B.; Zielke, Olaf; Jayko, A. S.; Burgmann, R.

    2016-01-01

    The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross-correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) for each measurement. Stacking PDFs along strike to form cumulative offset probability distribution plots (COPDs) highlights common values corresponding to single and multiple-event displacements. Lateral offsets for 1872 vary systematically from approximate to 1.0 to 6.0 m and average 3.31.1 m (2 sigma). Vertical offsets are predominantly east-down between approximate to 0.1 and 2.4 m, with a mean of 0.80.5 m. The average lateral-to-vertical ratio compiled at specific sites is approximate to 6:1. Summing displacements across subparallel, overlapping rupture traces implies a maximum of 7-11 m and net average of 4.41.5 m, corresponding to a geologic M-w approximate to 7.5 for the 1872 event. We attribute progressively higher-offset lateral COPD peaks at 7.12.0 m, 12.8 +/- 1.5 m, and 16.6 +/- 1.4 m to three earlier large surface ruptures. Evaluating cumulative displacements in context with previously dated landforms in Owens Valley suggests relatively modest rates of fault slip, averaging between approximate to 0.6 and 1.6 mm/yr (1 sigma) over the late Quaternary.

  18. Surface slip during large Owens Valley earthquakes

    Science.gov (United States)

    Haddon, E.K.; Amos, C.B.; Zielke, O.; Jayko, Angela S.; Burgmann, R.

    2016-01-01

    The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross-correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) for each measurement. Stacking PDFs along strike to form cumulative offset probability distribution plots (COPDs) highlights common values corresponding to single and multiple-event displacements. Lateral offsets for 1872 vary systematically from ∼1.0 to 6.0 m and average 3.3 ± 1.1 m (2σ). Vertical offsets are predominantly east-down between ∼0.1 and 2.4 m, with a mean of 0.8 ± 0.5 m. The average lateral-to-vertical ratio compiled at specific sites is ∼6:1. Summing displacements across subparallel, overlapping rupture traces implies a maximum of 7–11 m and net average of 4.4 ± 1.5 m, corresponding to a geologic Mw ∼7.5 for the 1872 event. We attribute progressively higher-offset lateral COPD peaks at 7.1 ± 2.0 m, 12.8 ± 1.5 m, and 16.6 ± 1.4 m to three earlier large surface ruptures. Evaluating cumulative displacements in context with previously dated landforms in Owens Valley suggests relatively modest rates of fault slip, averaging between ∼0.6 and 1.6 mm/yr (1σ) over the late Quaternary.

  19. Surface slip during large Owens Valley earthquakes

    KAUST Repository

    Haddon, E. K.

    2016-01-10

    The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross-correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) for each measurement. Stacking PDFs along strike to form cumulative offset probability distribution plots (COPDs) highlights common values corresponding to single and multiple-event displacements. Lateral offsets for 1872 vary systematically from approximate to 1.0 to 6.0 m and average 3.31.1 m (2 sigma). Vertical offsets are predominantly east-down between approximate to 0.1 and 2.4 m, with a mean of 0.80.5 m. The average lateral-to-vertical ratio compiled at specific sites is approximate to 6:1. Summing displacements across subparallel, overlapping rupture traces implies a maximum of 7-11 m and net average of 4.41.5 m, corresponding to a geologic M-w approximate to 7.5 for the 1872 event. We attribute progressively higher-offset lateral COPD peaks at 7.12.0 m, 12.8 +/- 1.5 m, and 16.6 +/- 1.4 m to three earlier large surface ruptures. Evaluating cumulative displacements in context with previously dated landforms in Owens Valley suggests relatively modest rates of fault slip, averaging between approximate to 0.6 and 1.6 mm/yr (1 sigma) over the late Quaternary.

  20. A Case Study On Human Capital Mismanagement In The United States Air Force

    Science.gov (United States)

    2016-05-08

    AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY A Case Study on Human Capital Mismanagement in the United States Air Force By John P...Force does not effectively manage its human capital to develop and retain a technically literate acquisitions workforce. A detailed look at the...Several solutions are suggested to improve the human capital management and increase the quality and relevancy of the acquisitions community at

  1. Atomistic simulations of screw dislocation cross slip in copper and nickel

    DEFF Research Database (Denmark)

    Vegge, Tejs

    2001-01-01

    This paper presents calculations of screw dislocation cross slip in copper and nickel systems, using the nudged elastic band method and interatomic potentials based on the effective-medium theory. The validity of recent attempts to predict cross slip activation energies by ‘elastic scaling’ between...

  2. The complex evolution of transient slip revealed by precise tremor locations in western Shikoku, Japan

    Science.gov (United States)

    Shelly, D. R.; Beroza, G. C.; Ide, S.

    2007-12-01

    Transient slow slip events are increasingly being recognized as important components of strain release on faults and may substantially impact the earthquake cycle. Surface-based geodetic instruments provide estimates of the overall slip distribution in larger transients but are unable to capture the detailed evolution of such slip, either in time or space. Accompanying some of these slip transients is a relatively weak, extended duration seismic signal, known as non-volcanic tremor, which has recently been shown to be generated by a sequence of shear failures occurring as part of the slip event. By precisely locating the tremor, we can track some features of slip evolution with unprecedented resolution. Here, we analyze two weeklong episodes of tremor and slow slip in western Shikoku, Japan. We find that these slip transients do not evolve in a smooth and steady fashion but contain numerous sub-events of smaller size and shorter duration. In addition to along-strike migration rates of about 10 km/day observed previously, much faster migration also occurs, usually in the slab dip direction, at rates of 25-150 km/hour over distances of up to 20 km. We observe such migration episodes in both the up-dip and down-dip directions. These episodes may be most common on certain portions of the plate boundary that generate strong tremor in intermittent bursts. The surrounding regions of the fault may slip more continuously, driving these stronger patches to repeated failures. Tremor activity has a strong tidal periodicity, possibly reflecting the modulation of slow slip velocity by tidal stresses.

  3. From political capitalism to clientelist capitalism? The case of Croatia

    Directory of Open Access Journals (Sweden)

    Denis Redžepagić

    2011-12-01

    Full Text Available The paper analyses the typology of capitalism in Croatia. The Croatian form of capitalism is specific, in form and origin, with links between the pre-independence and post-independence periods, implying that capitalism has gradually evolved – from the political during the eighties towards current clientelistic capitalism. The manufacturing focus aims to facilitate the analysis of institutional, political and economic changes over the past forty years, emphasising the implications of institutional changes which have to a great extent, apart from the war of course, influenced the evolution of capitalism. The paper finds that the transition generated a number of costs, mainly generated by the state (fall in employment, manufacturing and social capital. The claim that the manufacturing industry has inherited low competitiveness neglects the necessary discussion on the role of the state in the formation of industrial policy and market actions. It is also an ex post argument for the claim that restructuring should have been implemented prior to privatisation as this would reduce negative impacts. Institutional changes led to a drastic reduction of the role of the manufacturing sector in the economy. The main finding in this paper is that the change in the interaction between the financial and the real sectors of the economy, the educational system and industrial relations system exposed the vulnerability of the current institutional environment. Despite similarities, institutional advantages of political capitalism are lost in the new type of Croatian capitalism, due to the complexity of the double transition process and the institutional or socio-economic particularities.

  4. Mirror-like slip surfaces in dolostone: natural and experimental constraints on a potential seismic marker

    Science.gov (United States)

    Fondriest, M.; Smith, S. A.; Di Toro, G.; Nielsen, S. B.

    2012-12-01

    The lack of clear geological markers of seismic faulting represents a major limitation in our current comprehension of earthquake physics. At present pseudotachylytes (i.e. friction-induced melts) are the only unambiguously identified indicator of ancient seismicity in exhumed fault zones, but pseudotachylytes are not found in many rock types, including carbonates. We report the occurrence of small-displacement, mirror-like slip surfaces from a fault zone cutting dolostones. A combination of field observations and rotary shear friction experiments suggests that such slip surfaces: 1) are formed only at seismic slip rates, and 2) could potentially be used to estimate power dissipation during individual slip events. The Foiana Line (FL) is a major NNE-SSW-trending sinistral transpressive fault in the Italian Southern Alps. The outcropping fault zone consists of a rotary-shear experiments using SHIVA (INGV, Rome) were performed on 3 mm thick layers of dolomite gouge (grain size friction coefficient (μ) from a peak value of ~0.7 to a steady-state value of ~0.25. The gouge starts to weaken above a threshold velocity in the range 0.19-0.49 m/s following a transient phase of strengthening. During the tests the instantaneous power density (shear stress*slip rate) dissipated on the sample reaches values of 6-10 MW/m2 over distances of 0.02-1 m, comparable to those of natural earthquakes. At 26 MPa normal stress a mirror-like slip surface is formed after only 0.03 m of slip. At intermediate slip rates (0.113 m/s) only moderate reductions in μ are observed. Instantaneous power density is ~1 MW/m2 and the mirror-like slip surface starts to develop after 0.1 m of slip. At sub-seismic slip rates (0.0001-0.0013 m/s) μ remains ~0.7, instantaneous power density is ~0.02 MW/m2, and no mirror-like slip surface develops. Microstructural observations suggest that the natural and experimental slip zones are comparable: both have a compacted layer up to 20 μm thick immediately below

  5. Hydrodynamics beyond Navier-Stokes: the slip flow model.

    Science.gov (United States)

    Yudistiawan, Wahyu P; Ansumali, Santosh; Karlin, Iliya V

    2008-07-01

    Recently, analytical solutions for the nonlinear Couette flow demonstrated the relevance of the lattice Boltzmann (LB) models to hydrodynamics beyond the continuum limit [S. Ansumali, Phys. Rev. Lett. 98, 124502 (2007)]. In this paper, we present a systematic study of the simplest LB kinetic equation-the nine-bit model in two dimensions--in order to quantify it as a slip flow approximation. Details of the aforementioned analytical solution are presented, and results are extended to include a general shear- and force-driven unidirectional flow in confined geometry. Exact solutions for the velocity, as well as for pertinent higher-order moments of the distribution functions, are obtained in both Couette and Poiseuille steady-state flows for all values of rarefaction parameter (Knudsen number). Results are compared with the slip flow solution by Cercignani, and a good quantitative agreement is found for both flow situations. Thus, the standard nine-bit LB model is characterized as a valid and self-consistent slip flow model for simulations beyond the Navier-Stokes approximation.

  6. Preliminary slip history of the 2002 Denali earthquake

    Science.gov (United States)

    Ji, C.; Helmberger, D.; Wald, D.

    2002-12-01

    Rapid slip histories for the 2002 Denali earthquake were derived from the IRIS global data before geologists arrived in the field. We were able to predict many of the features they observed. Three models were produced indicating a step-wise improvement in matching the waveform data applying a formalism discussed in Ji et al. (2002). The first model referred to as Phase I is essentially an automated solution where a simple fault plane (300 km long) is fixed agreeing with CMT (Harvard) solution (strike 298 dip =86) assuming the PDE epicenter. The fit to the initial P waves does not work since they do not display a strike-slip polarity pattern. Thus, to continue we added a thrusting event (Phase II) following roughly the fault geometry of the Denali fault based on DEM topography map. While this produced some improvements, major misfits still remained. Before proceeding with Phase III, we did some homework on a foreshock, the Mw=6.7 Nenana event. After modeling this strike-slip event as a distributed fault, we used this relatively simple event to calibrate paths where shifts in P-waves and SH-waves ranged up to 4 and 8 sec respectively. Applying these corrections revealed some discrepancies in the rupture initiation. To produce a consistent picture requires 4 fault segments A, B, C and D. A weak rupture may initiate on a strike-slip Denali fault branch A at a depth of 10 km where a low angle thrust fault plane B intersects A. After about 2 sec, a major event occurred on plane B (strike=221, dip=35) and dominated the rupture of next 8 sec. When rupture B reaches the surface at about 10 sec after initiation, the major portion of the Denali fault (segment C) ruptured eastward with a relatively fast velocity (3 km/sec) producing a large slip concentration (up to 9 m at a depth of 10 km). The surface slip is about 7 km at a 20 km long segment. This feature is near the intersection of the Denali fault and the Totichunda fault (branch D). The rupture on D is relatively

  7. Oscillatory Stokes Flow Past a Slip Cylinder

    Science.gov (United States)

    Palaniappan, D.

    2013-11-01

    Two-dimensional transient slow viscous flow past a circular cylinder with Navier slip boundary conditions is considered in the limit of low-Reynolds number. The oscillatory Stokes flow problem around a cylinder is solved using the stream function method leading to an analytic solution in terms of modified Bessel functions of the second kind. The corresponding steady-state behavior yields the familiar paradoxical result first detected by Stokes. It is noted that the two key parameters, viz., the frequency λ, and the slip coefficient ξ have a significant impact on the flow field in the vicinity of the cylinder contour. In the limit of very low frequency, the flow is dominated by a term containing a well-known biharmonic function found by Stokes that has a singular behavior at infinity. Local streamlines for small times show interesting flow patterns. Attached eddies due to flow separation - observed in the no-slip case - either get detached or pushed away from the cylinder surface as ξ is varied. Computed asymptotic results predict that the flow exhibits inviscid behavior far away from the cylinder in the frequency range 0 < λ << 1 . Although the frequency of oscillations is finite, our exact solutions reveal fairly rapid transitions in the flow domain. Research Enhancement grant, TAMUCC.

  8. Slip-stick excitation and travelling waves excite silo honking

    Directory of Open Access Journals (Sweden)

    Warburton Katarzyna

    2017-01-01

    Full Text Available Silo honking is the harmonic sound generated by the discharge of a silo filled with a granular material. In industrial storage silos, the acoustic emission during discharge of PET-particles forms a nuisance for the environment and may ultimately result in structural failure. This work investigates the phenomenon experimentally using a laboratory-scale silo, and successfully correlates the frequency of the emitted sound with the periodicity of the mechanical motion of the grains. The key driver is the slip-stick interaction between the wall and the particles, characterized as a wave moving upwards through the silo. A quantitative correlation is established for the first time between the frequency of the sound, measured with an electret microphone, and the slip-frequency, measured with a high-speed camera. In the lower regions of the tube, both the slip-stick motion and the honking sound disappear.

  9. Retention of the "first-trial effect" in gait-slip among community-living older adults.

    Science.gov (United States)

    Liu, Xuan; Bhatt, Tanvi; Wang, Shuaijie; Yang, Feng; Pai, Yi-Chung Clive

    2017-02-01

    "First-trial effect" characterizes the rapid adaptive behavior that changes the performance outcome (from fall to non-fall) after merely a single exposure to postural disturbance. The purpose of this study was to investigate how long the first-trial effect could last. Seventy-five (≥ 65 years) community-dwelling older adults, who were protected by an overhead full body harness system, were retested for a single slip 6-12 months after their initial exposure to a single gait-slip. Subjects' body kinematics that was used to compute their proactive (feedforward) and reactive (feedback) control of stability was recorded by an eight-camera motion analysis system. We found the laboratory falls of subjects on their retest slip were significantly lower than that on the novel initial slip, and the reactive stability of these subjects was also significantly improved. However, the proactive stability of subjects remains unchanged between their initial slip and retest slip. The fall rates and stability control had no difference among the 6-, 9-, and 12-month retest groups, which indicated a maximum retention on 12 months after a single slip in the laboratory. These results highlighted the importance of the "first-trial effect" and suggested that perturbation training is effective for fall prevention, with lower trial doses for a long period (up to 1 year). Therefore, single slip training might benefit those older adults who could not tolerate larger doses in reality.

  10. Bond-Slip Relationship for CFRP Sheets Externally Bonded to Concrete under Cyclic Loading.

    Science.gov (United States)

    Li, Ke; Cao, Shuangyin; Yang, Yue; Zhu, Juntao

    2018-02-26

    The objective of this paper was to explore the bond-slip relationship between carbon fiber-reinforced polymer (CFRP) sheets and concrete under cyclic loading through experimental and analytical approaches. Modified beam tests were performed in order to gain insight into the bond-slip relationship under static and cyclic loading. The test variables are the CFRP-to-concrete width ratio, and the bond length of the CFRP sheets. An analysis of the test results in this paper and existing test results indicated that the slope of the ascending segment of the bond-slip curve decreased with an increase in the number of load cycles, but the slip corresponding to the maximum shear stress was almost invariable as the number of load cycles increased. In addition, the rate of reduction in the slope of the ascending range of the bond-slip curve during cyclic loading decreased as the concrete strength increased, and increased as the load level or CFRP-to-concrete width ratio enhanced. However, these were not affected by variations in bond length if the residual bond length was longer than the effective bond length. A bilinear bond-slip model for CFRP sheets that are externally bonded to concrete under cyclic loading, which considered the effects of the cyclic load level, concrete strength, and CFRP-to-concrete ratio, was developed based on the existing static bond-slip model. The accuracy of this proposed model was verified by a comparison between this proposed model and test results.

  11. Bond–Slip Relationship for CFRP Sheets Externally Bonded to Concrete under Cyclic Loading

    Science.gov (United States)

    Li, Ke; Cao, Shuangyin; Yang, Yue; Zhu, Juntao

    2018-01-01

    The objective of this paper was to explore the bond–slip relationship between carbon fiber-reinforced polymer (CFRP) sheets and concrete under cyclic loading through experimental and analytical approaches. Modified beam tests were performed in order to gain insight into the bond–slip relationship under static and cyclic loading. The test variables are the CFRP-to-concrete width ratio, and the bond length of the CFRP sheets. An analysis of the test results in this paper and existing test results indicated that the slope of the ascending segment of the bond–slip curve decreased with an increase in the number of load cycles, but the slip corresponding to the maximum shear stress was almost invariable as the number of load cycles increased. In addition, the rate of reduction in the slope of the ascending range of the bond–slip curve during cyclic loading decreased as the concrete strength increased, and increased as the load level or CFRP-to-concrete width ratio enhanced. However, these were not affected by variations in bond length if the residual bond length was longer than the effective bond length. A bilinear bond–slip model for CFRP sheets that are externally bonded to concrete under cyclic loading, which considered the effects of the cyclic load level, concrete strength, and CFRP-to-concrete ratio, was developed based on the existing static bond–slip model. The accuracy of this proposed model was verified by a comparison between this proposed model and test results. PMID:29495383

  12. Profitability Identification of National Banking Through Credit, Capital, Capital Structure, Efficiency, and Risk Level

    Directory of Open Access Journals (Sweden)

    Sugeng Haryanto

    2016-04-01

    Full Text Available This study aims to analyze the influence of credit, bank capital, capital structure, efficiency and risk toward the profitability in banking industry. Bank has an important role in the economy in Indonesia in 2014. The purposive sampling technique was used in this study to filter the samples according to several criteria such as being public at least in 2008, and publicly released the financial statement from 2008-2013. The total sample of 25 banks. Multiple regression technique was used in this study to analyze the data. The results show that credit, bank capital, and capital structure positively influence the profitability. This result supported by the previous research. The other finding shows that efficiency and risk have significantly negative effect on profitability. Bangking has an 80 percent market share in the financing of intermediation function of the entire financial system.Penelitian bertujuan menganalisis pengaruh antara kredit, permodalan bank, struktur modal, efisiensi dan risiko terhadap profitabilitas pada industri perbankan. Bank mempunyai peran penting dalam ekonomi Indonesia 2014. Teknik sampling penelitian ini adalah purposive sampling, dengan kriteria bank bank telah go public sebelum tahun 2008, mempublikasikan laporan keuangan tahun 2008-2013. Jumlah sampel sebanyak 25 bank. Teknik analisis yang digunakan regresi linier berganda. Hasil penelitian menunjukkan bahwa kredit, permodalan bank dan struktur modal berpengaruh terhadap profitabilitas dengan arah positif. Hasil lainnya adalah variabel efisiensi dan risiko berpengaruh signifikan dengan arah negatif terhadap profitabilitas. Perbankan memiliki market share 80 persen dalam sistem keuangan.JEL Classification: G3, G32

  13. Social Capital, Well-Being and Municipality: Salaspils Municipality (Latvia Case

    Directory of Open Access Journals (Sweden)

    Jēkabsone Inga

    2016-06-01

    Full Text Available During the last three decades, social capital has gained prominence throughout the social sciences. The concepts has been analysed in various manners (from perspectives of economics, political sciences, sociology, anthropology etc. providing wide range of theoretical conceptualizations. The aim of paper is to analyse the relation of social capital and possibility to improve the well-being of the municipality’s citizens using co-responsibility approach. In order to achieve the aim, the tasks are formulated as follows: 1 to review theoretical background for concept of social capital and subjective well-being, 2 to analyse the factors of social capital at local level, and 3 to use the results of conducted empirical research at Salaspils municipality in analysing the correlation of level of social capital and possibility to improve well-being implementing inclusive local management. Research methods used: Scientific literature studies, several stages of focus group discussions, statistical data analysis, SPIRAL methodology, scenario method. The main findings of the paper - there are evidences on relation of social capital and possibility to improve the well-being of the municipality’s citizens. In municipalities with sufficient level of social capital are good opportunities to use participatory techniques for achieving higher level of overall well-being. The paper consists of practical value how to mobilise the social capital of the municipality in order to ensure the inclusive management of the territory.

  14. Episodic slow slip events in the Japan subduction zone before the 2011 Tohoku-Oki earthquake

    Science.gov (United States)

    Ito, Yoshihiro; Hino, Ryota; Kido, Motoyuki; Fujimoto, Hiromi; Osada, Yukihito; Inazu, Daisuke; Ohta, Yusaku; Iinuma, Takeshi; Ohzono, Mako; Miura, Satoshi; Mishina, Masaaki; Suzuki, Kensuke; Tsuji, Takeshi; Ashi, Juichiro

    2013-07-01

    We describe two transient slow slip events that occurred before the 2011 Tohoku-Oki earthquake. The first transient crustal deformation, which occurred over a period of a week in November 2008, was recorded simultaneously using ocean-bottom pressure gauges and an on-shore volumetric strainmeter; this deformation has been interpreted as being an M6.8 episodic slow slip event. The second had a duration exceeding 1 month and was observed in February 2011, just before the 2011 Tohoku-Oki earthquake; the moment magnitude of this event reached 7.0. The two events preceded interplate earthquakes of magnitudes M6.1 (December 2008) and M7.3 (March 9, 2011), respectively; the latter is the largest foreshock of the 2011 Tohoku-Oki earthquake. Our findings indicate that these slow slip events induced increases in shear stress, which in turn triggered the interplate earthquakes. The slow slip event source area on the fault is also located within the downdip portion of the huge-coseismic-slip area of the 2011 earthquake. This demonstrates episodic slow slip and seismic behavior occurring on the same portions of the megathrust fault, suggesting that the faults undergo slip in slow slip events can also rupture seismically.

  15. Shoe sole tread designs and outcomes of slipping and falling on slippery floor surfaces.

    Directory of Open Access Journals (Sweden)

    Li-Wen Liu

    Full Text Available A gait experiment was conducted under two shoe sole and three floor conditions. The shoe soles and floors were characterized by the tread and groove designs on the surface. The coefficients of friction (COF on the floor in the target area were measured. The subjects were required to walk on a walkway and stepping on a target area covered with glycerol. The motions of the feet of the subjects were captured. Gait parameters were calculated based on the motion data. Among the 240 trials, there were 37 no-slips, 81 microslips, 45 slides, and 77 slips. It was found that the condition with shoe sole and floor had both tread grooves perpendicular to the walking direction had the highest COF, the shortest slip distance, and the lowest percentages of slide and slip. The condition with shoe sole and floor had both tread grooves parallel to the walking direction had the lowest COF and the longest slip distance among all experimental conditions. The Pearson's correlation coefficients between slip distance and slip velocity, time to foot flat, foot angle, and compensatory step length were 0.82 (p<0.0001, 0.33 (p<0.0001, -0.54 (p<0.0001, and -0.51 (p<0.0001, respectively.

  16. Investigation of torque control using a variable slip induction generator

    Energy Technology Data Exchange (ETDEWEB)

    Bossanyi, E A; Gamble, C R

    1991-07-01

    An investigation of the possibilities of using a variable slip induction generator to control wind turbine transmission torque has been carried out. Such a generator consists of a wound rotor induction generator with its rotor winding connected to an external variable resistance circuit. By controlling the external resistance, the torque-slip characteristic of the generator can be modified, allowing efficient, low-slip operation below rated wind speed and compliant, high-slip operation above rated, where the additional losses are of no consequence but the resulting compliance allows a much reduced duty to be specified for the transmission and gearbox. A number of hardware options have been investigated for the variable resistance rotor circuit, the main options being either a rectifier and DC chopper or an AC regulator. Both of these options use semiconductor switching devices, for which the relative merits of thyristors, MOSFETs, GTOs and transistors have been investigated. A favoured scheme consisting of an AC regulator using GTOs has been provisionally selected. This choice uses some non-standard equipment but is expected to give negligible problems with harmonics. A comprehensive simulation model has been set up and used to investigate the behaviour of the whole system. (author).

  17. Entrepreneurs’ human and social capital

    DEFF Research Database (Denmark)

    Shayegheh Ashourizadeh, Shayegheh; Rezaei, Shahamak; Schøtt, Thomas

    2014-01-01

    Abstract: It is widely acknowledged that entrepreneurs’ human capital in form of education and social capital in form of networking are mutually beneficial and also that both human and social capital benefit their performance. Here, the hypothesis is that human and social capital, in combination......, provide added value and jointly add a further boost to performance, specifically if the form of exporting. Global Entrepreneurship Monitor provides data on 52,946 entrepreneurs, who reported on exporting and networking for advice. Hierarchical linear modelling shows that human capital promotes social...... capital, that human capital and social capital (specifically networking in the international environment, work-place, professions and market, but not in the private sphere) both benefit export directly and that human capital amplifies the benefit of social capital, especially through international...

  18. Shear Slip Potential Induced by Thermomechanical Loading in an Underground Repository for Nuclear Waste

    International Nuclear Information System (INIS)

    Lee, Jaewon; Min, Kibok; Stephansson, Ove

    2010-01-01

    In the context of a deep geological repository for nuclear water, the thermal stress generated by nuclear waster is expected to contribute to shear slip and dilation, which will eventually alter the fracture permeability in the region. In this study, the probability of the occurrence of shear slip at a fracture was examined by the Mohr-Coulomb failure criterion. The study was based on the fracture orientation generated by the Latin hypercube sampling method, which can improve the efficiency of Monte Carlo simulations by the use of a more systematic approach for selecting the input samples. Statistical data of fracture orientations from the site investigation in Forsmark, Sweden, were used in this study. The historical assessment of thermal stress was based on three-dimensional finite element modeling of a geological repository that measures 800 m by 2000 m and on a time scale up to 10,000 years. The results show that the probability of shear slip evolved differently at six selected points due to the difference stresses at each point. However, it was evident that the probability of shear slip was more that twice as large as the initial probability of failure. This increased permeability and micro seismicity, which can be an issue during the initial operation of the repository. The study provided a quantitative assessment of the probability of shear slip at a fracture, which is an important parameter for assessing the performance of a geological repository. Conclusions are summarized as follows: · With random orientation data, the probability of shear slip around the repository model increases with increased thermal stress. · The probability of shear slip depends on the manner in which the thermal stress is generated. Higher shear slip is expected with higher differential thermal stress. · The probability of shear slip at Forsmark was less than 1 %. If different sites have fracture sets with more overlap, however, the probability may become increase. Therefore, a

  19. The influence of testing apparatus stiffness on the source properties of laboratory stick-slip

    Science.gov (United States)

    Kilgore, B. D.; McGarr, A.; Beeler, N. M.; Lockner, D. A.

    2016-12-01

    Stick-slip experiments were performed to determine the influence of the testing apparatus stiffness on source properties, to develop methods to relate stick-slip to natural earthquakes, and to examine the hypothesis of McGarr [2012] that the product of unloading stiffness, k, and slip duration, T, is both scale-independent and approximately constant for both laboratory and natural earthquakes. A double-direct shear load frame was used with Sierra White Granite samples at 2 MPa normal stress, and a remote loading rate of 0.2 µm/s. The stiffness of the test apparatus was varied by more than an order of magnitude by inserting disk springs into the shear loading column adjacent to the granite samples. Servo-controlling slip at a point between the forcing ram and the shear force load cell, produced repeatable slip events. Slip and slip duration decrease as k increases, as they do for natural earthquakes. In contrast to earthquakes, stress drop and slip rate decrease with increasing k, and the product kT for these experiments is not constant, but decreases with k. These data, collected over a range of k, do not conform to McGarr's [2012] hypothesis. However, analysis of stick-slip studies from other testing apparatuses is consistent with McGarr's hypothesis; kT is scale-independent, similar to that of earthquakes, equal to the ratio of static stress drop to average slip velocity, and similar to the ratio of shear modulus to wavespeed of rock. These properties result from conducting experiments over a range of sample sizes, using rock samples with the same elastic properties as the Earth, and using testing machines whose stiffnesses decrease, and characteristic periods increase with scale. A consequence of our experiments and analysis is that extrapolation of lab scale earthquake source properties to the Earth is more difficult than previously thought, requiring an accounting for the properties of the testing machines and additional research beyond that reported here.

  20. Wenchuan Ms8.0 earthquake coseismic slip distribution inversion

    Directory of Open Access Journals (Sweden)

    Hongbo Tan

    2015-05-01

    Full Text Available By using GPS and gravity data before and after the Wenchuan Ms8.0 earthquake and combining data from geological surveys and geophysical inversion studies, an initial coseismic fault model is constructed. The dip angle changes of the fault slip distribution on the fault plane are inversed, and the inversion results show that the shape of the fault resembles a double-shovel. The Yingxiu–Beichuan Fault is approximately 330 km long, the surface fault dip angle is 65.1°, which gradually reduces with increasing depth to 0° at the detachment layer at a depth of 19.62 km. The Guanxian–Jiangyou Fault is approximately 90 km long, and its dip angle at the surface is 55.3°, which gradually reduces with increasing depth; the fault joins the Yingxiu–Beichuan Fault at 13.75 km. Coseismic slip mainly occurs above a depth of 19 km. There are five concentrated rupture areas, Yingxiu, Wenchuan, Hanwang, Beichuan, and Pingwu, which are consistent with geological survey results and analyses of the aftershock distribution. The rupture mainly has a thrust component with a small dextral strike–slip component. The maximum slip was more than 10 m, which occurred near Beichuan and Hanwang. The seismic moment is 7.84 × 1020 Nm (Mw7.9, which is consistent with the seismological results.

  1. Thermally activated phase slips of one-dimensional Bose gases in shallow optical lattices

    Science.gov (United States)

    Kunimi, Masaya; Danshita, Ippei

    2017-03-01

    We study the decay of superflow via thermally activated phase slips in one-dimensional Bose gases in a shallow optical lattice. By using the Kramers formula, we numerically calculate the nucleation rate of a thermally activated phase slip for various values of the filling factor and flow velocity in the absence of a harmonic trapping potential. Within the local density approximation, we derive a formula connecting the phase-slip nucleation rate with the damping rate of a dipole oscillation of the Bose gas in the presence of a harmonic trap. We use the derived formula to directly compare our theory with the recent experiment done by the LENS group [L. Tanzi et al., Sci. Rep. 6, 25965 (2016), 10.1038/srep25965]. From the comparison, the observed damping of dipole oscillations in a weakly correlated and small velocity regime is attributed dominantly to thermally activated phase slips rather than quantum phase slips.

  2. Seismic potential of weak, near-surface faults revealed at plate tectonic slip rates.

    Science.gov (United States)

    Ikari, Matt J; Kopf, Achim J

    2017-11-01

    The near-surface areas of major faults commonly contain weak, phyllosilicate minerals, which, based on laboratory friction measurements, are assumed to creep stably. However, it is now known that shallow faults can experience tens of meters of earthquake slip and also host slow and transient slip events. Laboratory experiments are generally performed at least two orders of magnitude faster than plate tectonic speeds, which are the natural driving conditions for major faults; the absence of experimental data for natural driving rates represents a critical knowledge gap. We use laboratory friction experiments on natural fault zone samples at driving rates of centimeters per year to demonstrate that there is abundant evidence of unstable slip behavior that was not previously predicted. Specifically, weak clay-rich fault samples generate slow slip events (SSEs) and have frictional properties favorable for earthquake rupture. Our work explains growing field observations of shallow SSE and surface-breaking earthquake slip, and predicts that such phenomena should be more widely expected.

  3. Investment in capital markets

    OpenAIRE

    Ledenyov, Dimitri O.; Ledenyov, Viktor O.

    2017-01-01

    Investment in Capital Markets creates a strategic vision on the financial capital investment in the capital markets with the aim to get an increased return premium in the short and long time periods. The book is written with a main goal to explain the pros and cons of the financial capital investment in the capital markets, discussing the sophisticated investment concepts and techniques in the simple understandable readable general format language. We would like to highlight the three interes...

  4. Toward a neighborhood resource-based theory of social capital for health: can Bourdieu and sociology help?

    Science.gov (United States)

    Carpiano, Richard M

    2006-01-01

    Within the past several years, a considerable body of research on social capital has emerged in public health. Although offering the potential for new insights into how community factors impact health and well being, this research has received criticism for being undertheorized and methodologically flawed. In an effort to address some of these limitations, this paper applies Pierre Bourdieu's (1986) [Bourdieu, P. (1986). Handbook of theory and research for the sociology of education (pp. 241-258). New York: Greenwood] social capital theory to create a conceptual model of neighborhood socioeconomic processes, social capital (resources inhered within social networks), and health. After briefly reviewing the social capital conceptualizations of Bourdieu and Putnam, I attempt to integrate these authors' theories to better understand how social capital might operate within neighborhoods or local areas. Next, I describe a conceptual model that incorporates this theoretical integration of social capital into a framework of neighborhood social processes as health determinants. Discussion focuses on the utility of this Bourdieu-based neighborhood social capital theory and model for examining several under-addressed issues of social capital in the neighborhood effects literature and generating specific, empirically testable hypotheses for future research.

  5. Minority Capital Resource Handbook. A Guide to Raising Capital for Minority Entrepreneurs. Second Edition.

    Science.gov (United States)

    Ewing, Samuel D., Jr.; Maloney, Clifton H. W.

    This minority capital resource handbook consists of a guide to raising capital for minority entrepreneurs and a listing of sources that provide such capital. The first section deals with the process of raising capital. The realities of raising capital, intermediaries and financial advisors, and assessing needs are outlined. Factors considered in…

  6. Social Capital Database

    DEFF Research Database (Denmark)

    Paldam, Martin; Svendsen, Gert Tinggaard

    2005-01-01

      This report has two purposes: The first purpose is to present our 4-page question­naire, which measures social capital. It is close to the main definitions of social capital and contains the most successful measures from the literature. Also it is easy to apply as discussed. The second purpose...... is to present the social capital database we have collected for 21 countries using the question­naire. We do this by comparing the level of social capital in the countries covered. That is, the report compares the marginals from the 21 surveys....

  7. Giant slip at liquid-liquid interfaces using hydrophobic ball bearings.

    Science.gov (United States)

    Ehlinger, Quentin; Joly, Laurent; Pierre-Louis, Olivier

    2013-03-08

    Liquid-gas-liquid interfaces stabilized by hydrophobic beads behave as ball bearings under shear and exhibit a giant slip. Using a scaling analysis and molecular dynamics simulations we predict that, when the contact angle θ between the beads and the liquid is large, the slip length diverges as Rρ(-1)(π-θ)(-3) where R is the bead radius, and ρ is the bead density.

  8. The Performance of Intellectual Capital

    DEFF Research Database (Denmark)

    Murthy, Vijaya; Mouritsen, Jan

    2011-01-01

    Purpose – This paper aims to analyse the relationship between intellectual capital and financial capital using a case study. This makes it possible to discuss how intellectual capital is related to value creation with a degree of nuance that is absent from most statistical studies of relationships...... between human, organisational, relational and financial capital. Design/methodology/approach – The paper uses a case study of a firm that invests in intellectual capital in order to develop financial capital. It traces the relationship between intellectual capital elements and financial capital via...... interviews. This allows the development of a nuanced account of the performance of intellectual capital. This account questions the universality of the linear model typically found in statistical studies. The model makes it possible to show how items of intellectual capital not only interact but also compete...

  9. Dual megathrust slip behaviors of the 2014 Iquique earthquake sequence

    Science.gov (United States)

    Meng, Lingsen; Huang, Hui; Bürgmann, Roland; Ampuero, Jean Paul; Strader, Anne

    2015-02-01

    The transition between seismic rupture and aseismic creep is of central interest to better understand the mechanics of subduction processes. A Mw 8.2 earthquake occurred on April 1st, 2014 in the Iquique seismic gap of northern Chile. This event was preceded by a long foreshock sequence including a 2-week-long migration of seismicity initiated by a Mw 6.7 earthquake. Repeating earthquakes were found among the foreshock sequence that migrated towards the mainshock hypocenter, suggesting a large-scale slow-slip event on the megathrust preceding the mainshock. The variations of the recurrence times of the repeating earthquakes highlight the diverse seismic and aseismic slip behaviors on different megathrust segments. The repeaters that were active only before the mainshock recurred more often and were distributed in areas of substantial coseismic slip, while repeaters that occurred both before and after the mainshock were in the area complementary to the mainshock rupture. The spatiotemporal distribution of the repeating earthquakes illustrates the essential role of propagating aseismic slip leading up to the mainshock and illuminates the distribution of postseismic afterslip. Various finite fault models indicate that the largest coseismic slip generally occurred down-dip from the foreshock activity and the mainshock hypocenter. Source imaging by teleseismic back-projection indicates an initial down-dip propagation stage followed by a rupture-expansion stage. In the first stage, the finite fault models show an emergent onset of moment rate at low frequency ( 0.5 Hz). This indicates frequency-dependent manifestations of seismic radiation in the low-stress foreshock region. In the second stage, the rupture expands in rich bursts along the rim of a semi-elliptical region with episodes of re-ruptures, suggesting delayed failure of asperities. The high-frequency rupture remains within an area of local high trench-parallel gravity anomaly (TPGA), suggesting the presence of

  10. Inhibition of ice nucleation by slippery liquid-infused porous surfaces (SLIPS).

    Science.gov (United States)

    Wilson, Peter W; Lu, Weizhe; Xu, Haojun; Kim, Philseok; Kreder, Michael J; Alvarenga, Jack; Aizenberg, Joanna

    2013-01-14

    Ice repellent coatings have been studied and keenly sought after for many years, where any advances in the durability of such coatings will result in huge energy savings across many fields. Progress in creating anti-ice and anti-frost surfaces has been particularly rapid since the discovery and development of slippery, liquid infused porous surfaces (SLIPS). Here we use SLIPS-coated differential scanning calorimeter (DSC) pans to investigate the effects of the surface modification on the nucleation of supercooled water. This investigation is inherently different from previous studies which looked at the adhesion of ice to SLIPS surfaces, or the formation of ice under high humidity conditions. Given the stochastic nature of nucleation of ice from supercooled water, multiple runs on the same sample are needed to determine if a given surface coating has a real and statistically significant effect on the nucleation temperature. We have cycled supercooling to freezing and then thawing of deionized water in hydrophilic (untreated aluminum), hydrophobic, superhydrophobic, and SLIPS-treated DSC pans multiple times to determine the effects of surface treatment on the nucleation and subsequent growth of ice. We find that SLIPS coatings lower the nucleation temperature of supercooled water in contact with statistical significance and show no deterioration or change in the coating performance even after 150 freeze-thaw cycles.

  11. Simple Navier’s slip boundary condition for the non-Newtonian Lattice Boltzmann fluid dynamics solver

    DEFF Research Database (Denmark)

    Svec, Oldrich; Skoček, Jan

    2013-01-01

    The ability of the Lattice Boltzmann method, as the fluid dynamics solver, to properly simulate macroscopic Navier’s slip boundary condition is investigated. An approximate equation relating the Lattice Boltzmann variable slip boundary condition with the macroscopic Navier’s slip boundary condition...

  12. Calculations of intersection cross-slip activation energies in fcc metals using nudged elastic band method

    International Nuclear Information System (INIS)

    Rao, S.I.; Dimiduk, D.M.; Parthasarathy, T.A.; El-Awady, J.; Woodward, C.; Uchic, M.D.

    2011-01-01

    The nudged elastic band (NEB) method is used to evaluate activation energies for dislocation intersection cross-slip in face-centered cubic (fcc) nickel and copper, to extend our prior work which used an approximate method. In this work we also extend the study by including Hirth locks (HL) in addition to Lomer-Cottrell locks and glide locks (GL). Using atomistic (molecular statics) simulations with embedded atom potentials we evaluated the activation barrier for a dislocation to transform from fully residing on the glide plane to fully residing on the cross-slip plane when intersecting a 120 o forest dislocation in both Ni and Cu. The initial separation between the screw and the intersecting dislocation on the (1 1 1) glide plane is varied to find a minimum in the activation energy. The NEB method gives energies that are ∼10% lower than those reported in our prior work. It is estimated that the activation energies for cross-slip from the fully glide plane state to the partially cross-slipped state at the 120 o intersection forming GL in Ni and Cu are ∼0.47 and ∼0.65 eV, respectively, and from the fully cross-slip plane state to the partially cross-slipped state forming LC are ∼0.68 and ∼0.67 eV. The activation energies for cross-slip from the fully glide plane state to the partially cross-slipped state at the 120 o intersection forming HL in Ni and Cu are estimated to be ∼0.09 and ∼0.31 eV, respectively. These values are a factor of 3-20 lower than the activation energy for bulk cross-slip in Ni and, a factor of 2-6 lower than the activation energy for cross-slip in Cu estimated by Friedel-Escaig analysis. These results suggest that cross-slip should nucleate preferentially at selected screw dislocation intersections in fcc materials and the activation energies for such mechanisms are also a function of stacking fault energy.

  13. Effects of Spine Motion on Foot Slip in Quadruped Bounding

    Directory of Open Access Journals (Sweden)

    Dongliang Chen

    2018-01-01

    Full Text Available Translation and bend of the spine in the sagittal plane during high-speed quadruped running were investigated. The effect of the two spine motions on slip between the foot and the ground was also explored. First, three simplified sagittal plane models of quadruped mammals were studied in symmetric bounding. The first model’s trunk allowed no relative motion, the second model allowed only trunk bend, and the third model allowed both bend and translation. Next, torque was introduced to equivalently replace spine motion and the possibility of foot slip of the three models was analyzed theoretically. The results indicate that the third model has the least possibility of slip. This conclusion was further confirmed by simulation experiments. Finally, the conclusion was verified by the reductive model crawling robot.

  14. Slip analysis of squeezing flow using doubly stratified fluid

    Science.gov (United States)

    Ahmad, S.; Farooq, M.; Javed, M.; Anjum, Aisha

    2018-06-01

    The non-isothermal flow is modeled and explored for squeezed fluid. The influence of velocity, thermal and solutal slip effects on transport features of squeezed fluid are analyzed through Darcy porous channel when fluid is moving due to squeezing of upper plate towards the stretchable lower plate. Dual stratification effects are illustrated in transport equations. A similarity analysis is performed and reduced governing flow equations are solved using moderated and an efficient convergent approach i.e. Homotopic technique. The significant effects of physical emerging parameters on flow velocity, temperature and fluid concentration are reporting through various plots. Graphical explanations for drag force, Nusselt and Sherwood numbers are stated and examined. The results reveal that minimum velocity field occurs near the plate, whereas it increases far away from the plate for strong velocity slip parameter. Furthermore, temperature and fluid concentration significantly decreases with increased slip effects. The current analysis is applicable in some advanced technological processes and industrial fluid mechanics.

  15. Squeal vibrations, glass sounds, and the stick-slip effect

    International Nuclear Information System (INIS)

    Patitsas, A.J.

    2010-01-01

    The origin of the squeal acoustic emissions when a chalk is rubbed on a blackboard or better on a ceramic plate, and those when a wet finger is rubbed on a smooth surface, such as a glass surface, is sought in the stick-slip effect between the rubbing surfaces. In the case of the squealing chalk, the stick-slip effect is anchored by shear modes of vibration in about a 0.3 mm thick chalk powder band at the rubbing interface, while in the case of the wet finger on glass, by such modes in a band comprising the finger skin. Furthermore, there are the interfacial bands at the contact areas that result in the decrease of the friction coefficient with relative velocity of slide, i.e., the condition for the stick-slip effect to occur. Such bands are basically composed of the asperities on the surface of the chalk band and of the epidermis ridges and the water layer, respectively. (author)

  16. You have to be there to enjoy it? Neighbourhood social capital and health.

    NARCIS (Netherlands)

    Mohnen, S.M.; Völker, B.; Flap, H.; Subramanian, S.V.; Groenewegen, P.P.

    2013-01-01

    Background: Several studies have shown the positive effect of neighbourhood social capital on health. Existing research, however, has hitherto not studied whether the duration and intensity of exposure to neighbourhood social capital conditions and its effect on health. The aim of this study was to

  17. Cultural Capital: A Concept Analysis.

    Science.gov (United States)

    Ohashi, Yuki; Taguchi, Atsuko; Omori, Junko; Ozaki, Akiko

    2017-07-01

    Harnessing community assets may help public health nurses address health inequalities. Cultural factor is one such asset, which is assumed to be capital in a community. Cultural capital is a key concept for understanding the causes of public health issues. This paper provided an in-depth analysis of "cultural capital" as a concept. Rodgers' evolutionary methodology was used for concept analysis. Forty-two studies published in English between 1998 and 2015 were retrieved from MEDLINE by searching for "cultural capital" in the title field. Antecedents of cultural capital included "educational environment," "belongingness in one's social group," "existing health/social inequalities," and "daily behavior." Cultural capital's identified attributes were "social cultivation," "reproductive rubric," "practical knowledge," and "autogenic ability." Cultural capital's consequences were "improving productivity," "reducing health/social inequality," and "enhancing well-being." Cultural capital is defined as capital characterized by cultivation, rubric, knowledge, and ability. These aspects of cultural capital are typically autogenic, and accumulate and reproduce through lifelong community membership. Cultural capital reduces inequality and ultimately enhances the well-being of individuals and the community through bonding, bridging, and linking economic and social capital. © 2017 Wiley Periodicals, Inc.

  18. Quarterly Aggregate Capital Input and the Cost of Capital for the

    OpenAIRE

    Subhash C. Sharma; Yijian He

    1995-01-01

    It is the flow of capital services, instead of the capital stock, along with the flows of other inputs which is related to the flows of outputs in economic theory of cost and production. In applied research, quite often to capture the dynamic phenomena which occurs within a year, there is a need to use quarterly data which may not be captured by annual data. However, quarterly data on capital input and the cost of capital are not readily available. Thus, in this paper the quarterly real and n...

  19. Linear stability analysis of laminar flow near a stagnation point in the slip flow regime

    Science.gov (United States)

    Essaghir, E.; Oubarra, A.; Lahjomri, J.

    2017-12-01

    The aim of the present contribution is to analyze the effect of slip parameter on the stability of a laminar incompressible flow near a stagnation point in the slip flow regime. The analysis is based on the traditional normal mode approach and assumes parallel flow approximation. The Orr-Sommerfeld equation that governs the infinitesimal disturbance of stream function imposed to the steady main flow, which is an exact solution of the Navier-Stokes equation satisfying slip boundary conditions, is obtained by using the powerful spectral Chebyshev collocation method. The results of the effect of slip parameter K on the hydrodynamic characteristics of the base flow, namely the velocity profile, the shear stress profile, the boundary layer, displacement and momentum thicknesses are illustrated and discussed. The numerical data for these characteristics, as well as those of the eigenvalues and the corresponding wave numbers recover the results of the special case of no-slip boundary conditions. They are found to be in good agreement with previous numerical calculations. The effects of slip parameter on the neutral curves of stability, for two-dimensional disturbances in the Reynolds-wave number plane, are then obtained for the first time in the slip flow regime for stagnation point flow. Furthermore, the evolution of the critical Reynolds number against the slip parameter is established. The results show that the critical Reynolds number for instability is significantly increased with the slip parameter and the flow turn out to be more stable when the effect of rarefaction becomes important.

  20. Reducing Children’s Behavior Problems through Social Capital: A Causal Assessment

    Science.gov (United States)

    López Turley, Ruth N.; Gamoran, Adam; McCarty, Alyn Turner; Fish, Rachel

    2016-01-01

    Behavior problems among young children have serious detrimental effects on short and long-term educational outcomes. An especially promising prevention strategy may be one that focuses on strengthening the relationships among families in schools, or social capital. However, empirical research on social capital has been constrained by conceptual and causal ambiguity. This study attempts to construct a more focused conceptualization of social capital and aims to determine the causal effects of social capital on children’s behavior. Using data from a cluster randomized trial of 52 elementary schools, we apply several multilevel models to assess the causal relationship, including intent to treat and treatment on the treated analyses. Taken together, these analyses provide stronger evidence than previous studies that social capital improves children’s behavioral outcomes and that these improvements are not simply a result of selection into social relations but result from the social relations themselves. PMID:27886729

  1. A different capitalism? : Guanxi-capitalism and the importance of family in modern China

    OpenAIRE

    Rühle, Susanne

    2011-01-01

    The emergence of Capitalism is said to always lead to extreme changes in the structure of a society. This view implies that Capitalism is a universal and unique concept that needs an explicit institutional framework and should not discriminate between a German or US Capitalism. In contrast, this work argues that the ‘ideal type’ of Capitalism in a Weberian sense does not exist. It will be demonstrated that Capitalism is not a concept that shapes a uniform institutional framework within every ...

  2. Piketty’s Capital

    DEFF Research Database (Denmark)

    Larsen, Øjvind

    2016-01-01

    Piketty’s Capital in Twenty-First Century has posed a totally new platform for the discussion of the economy and capitalism. Piketty has reinvented the classical political economy founded by Adam Smith in his 1776 Wealth of Nations. Piketty has shown via massive historical research how growth...... and inequality have developed since 1793. Piketty’s conclusion is that the French Revolution did not change the existing inequality either in the medium or in the long term. Piketty’s prediction is that a new form of global capitalism will arise, patrimonial capitalism, in which inequality will develop further...

  3. Measuring Social Capital

    DEFF Research Database (Denmark)

    Svendsen, Gert Tinggaard; Bjørnskov, Christian

    2007-01-01

    How to construct a robust measure of social capital? This paper contains two contributions. The first is an attempt to establish a broad social capital measure based on four indicators, the Freedom House Index, an index of perceived corruption from Transparency International, and scores on civic...... participation and generalized trust. This measure is then applied by comparing the level of social capital in 25 countries from Western and Eastern Europe. Our nine cluster analysis shows that Switzerland has the highest score, followed by the Netherlands and Scandinavia. At the other end of the continuum we...... find post-communist countries and Southern Italy. The findings for this specific sample suggest that institutions matter for social capital and the relationship between decentralization and social capital emerges as a promising line of inquiry. Thus, the highest scoring countries in the sample may...

  4. Cultural Capital Today

    DEFF Research Database (Denmark)

    Prieur, Annick; Skjøtt-Larsen, Jakob; Rosenlund, Lennart

    2008-01-01

    Based on Danish survey data subjected to correspondence analysis, this article aims at carrying out a critical assessment of Pierre Bourdieu's theory of social differentiation in advanced societies as a multi-dimensional phenomenon. As his theory goes, capital volume (economic + cultural capital......) and capital composition (the relative weight of the two) are the main dimensions of social differentiation, which structure the space of social positions as well as the space of lifestyles. The central discussion of the article concerns the character of cultural capital, and the role it plays in the formation......, as those adhering to the preferences that are most typical for the cultural elite tend to simultaneously avoid or mark distance to popular expressions of taste. Fourth, are there traces of new forms of cultural capital? The study uncovers a cleavage between a global orientation or a form of cosmopolitanism...

  5. Activity of pyramidal I and II slip in Mg alloys as revealed by texture development

    Science.gov (United States)

    Zecevic, Miroslav; Beyerlein, Irene J.; Knezevic, Marko

    2018-02-01

    Due to the geometry of the hexagonal close-packed (HCP) lattice, there are two types of pyramidal slip modes: { 10 1 bar 1 } 〈 11 2 bar 3 bar 〉 or type I and { 1 bar 1 bar 22 } 〈 11 2 bar 3 〉 or type II in HCP crystalline materials. Here we use crystal plasticity to examine the importance of crystallographic slip by pyramidal type I and type II on texture evolution. The study is applied to an Mg-4%Li alloy. An elastic-plastic polycrystal model is employed to elucidate the reorientation tendencies of these two slip modes in rolling of a textured polycrystal. Comparisons with experimental texture measurements indicate that both pyramidal I and II type slip were active during rolling deformation, with pyramidal I being the dominant mode. A single-slip-mode analysis is used to identify the orientations that prefer pyramidal I vs. II type slip when acting alone in a crystal. The analysis applies not only to Mg-4%Li, but identifies the key texture components in HCP crystals that would help distinguish the activity of pyramidal I from pyramidal II slip in rolling deformation.

  6. Seismic slip recorded in tourmaline fault mirrors from Elba Island (Italy)

    Science.gov (United States)

    Viti, C.; Brogi, A.; Liotta, D.; Mugnaioli, E.; Spiess, R.; Dini, A.; Zucchi, M.; Vannuccini, G.

    2016-05-01

    This paper reports the first example of fault mirrors developed in an unusual protolith, consisting of tourmaline crystals with interstitial goethite. The deformation mechanisms active in the fault zone have been investigated from the outcrop to the nanoscale, aiming to identify possible traces of frictional heating at seismic slip rate, as observed for other fault mirrors in different protoliths. The investigation revealed the superposition of two main deformational stages. The first was dominated by brittle processes and produced a cataclastic/ultracataclastic principal slip zone, a few mm thick; the second was associated with seismic slip and produced a sharp discontinuity (the principal slip surface) within the cataclastic/ultracataclastic zone. The mirror-like coating, a few microns thick, occurs on the principal slip surface, and is characterized by 1) absence of interstitial goethite; 2) occurrence of truncated tourmaline crystals; 3) highly variable grain size, from 200 μm to 200 nm; 4) tourmaline close packing with interlobate grain boundaries, and 5) tourmaline random crystallographic orientation. Micro and nanostructural investigations indicate the occurrence of thermally-activated processes, involving both interstitial goethite and tourmaline. In particular, close to the principal slip surface, goethite is completely decomposed, and produced an amorphous porous material, with local topotactic recrystallization of hematite. Tourmaline clasts are typically characterized by strongly lobate boundaries, indicative of reaction and partial decomposition at grain boundaries. TEM observations revealed the occurrence of tourmaline nanograins, a few tens of nm in size, characterized by rounded shape and fading amorphous boundaries, that cannot be obtained by brittle processes. Lastly, the peculiar interlobate microstructure of the mirror surface is interpreted as the result of grain boundary recrystallization processes taking place by deformation at high

  7. EBSD analysis of subgrain boundaries and dislocation slip systems in Antarctic and Greenland ice

    Science.gov (United States)

    Weikusat, Ilka; Kuiper, Ernst-Jan N.; Pennock, Gill M.; Kipfstuhl, Sepp; Drury, Martyn R.

    2017-09-01

    Ice has a very high plastic anisotropy with easy dislocation glide on basal planes, while glide on non-basal planes is much harder. Basal glide involves dislocations with the Burgers vector b = 〈a〉, while glide on non-basal planes can involve dislocations with b = 〈a〉, b = [c], and b = 〈c + a〉. During the natural ductile flow of polar ice sheets, most of the deformation is expected to occur by basal slip accommodated by other processes, including non-basal slip and grain boundary processes. However, the importance of different accommodating processes is controversial. The recent application of micro-diffraction analysis methods to ice, such as X-ray Laue diffraction and electron backscattered diffraction (EBSD), has demonstrated that subgrain boundaries indicative of non-basal slip are present in naturally deformed ice, although so far the available data sets are limited. In this study we present an analysis of a large number of subgrain boundaries in ice core samples from one depth level from two deep ice cores from Antarctica (EPICA-DML deep ice core at 656 m of depth) and Greenland (NEEM deep ice core at 719 m of depth). EBSD provides information for the characterization of subgrain boundary types and on the dislocations that are likely to be present along the boundary. EBSD analyses, in combination with light microscopy measurements, are presented and interpreted in terms of the dislocation slip systems. The most common subgrain boundaries are indicative of basal 〈a〉 slip with an almost equal occurrence of subgrain boundaries indicative of prism [c] or 〈c + a〉 slip on prism and/or pyramidal planes. A few subgrain boundaries are indicative of prism 〈a〉 slip or slip of 〈a〉 screw dislocations on the basal plane. In addition to these classical polygonization processes that involve the recovery of dislocations into boundaries, alternative mechanisms are discussed for the formation of subgrain boundaries that are not related to the

  8. Effects of Strike-Slip Fault Segmentation on Earthquake Energy and Seismic Hazard

    Science.gov (United States)

    Madden, E. H.; Cooke, M. L.; Savage, H. M.; McBeck, J.

    2014-12-01

    Many major strike-slip faults are segmented along strike, including those along plate boundaries in California and Turkey. Failure of distinct fault segments at depth may be the source of multiple pulses of seismic radiation observed for single earthquakes. However, how and when segmentation affects fault behavior and energy release is the basis of many outstanding questions related to the physics of faulting and seismic hazard. These include the probability for a single earthquake to rupture multiple fault segments and the effects of segmentation on earthquake magnitude, radiated seismic energy, and ground motions. Using numerical models, we quantify components of the earthquake energy budget, including the tectonic work acting externally on the system, the energy of internal rock strain, the energy required to overcome fault strength and initiate slip, the energy required to overcome frictional resistance during slip, and the radiated seismic energy. We compare the energy budgets of systems of two en echelon fault segments with various spacing that include both releasing and restraining steps. First, we allow the fault segments to fail simultaneously and capture the effects of segmentation geometry on the earthquake energy budget and on the efficiency with which applied displacement is accommodated. Assuming that higher efficiency correlates with higher probability for a single, larger earthquake, this approach has utility for assessing the seismic hazard of segmented faults. Second, we nucleate slip along a weak portion of one fault segment and let the quasi-static rupture propagate across the system. Allowing fractures to form near faults in these models shows that damage develops within releasing steps and promotes slip along the second fault, while damage develops outside of restraining steps and can prohibit slip along the second fault. Work is consumed in both the propagation of and frictional slip along these new fractures, impacting the energy available

  9. The Distinct Character of a Capital? From Formality to Regularity of Our Ancient Capitals

    Science.gov (United States)

    Kelly, T.

    2018-04-01

    Many cities were shaped by dynamics political and commercial factors and man-made layers whereas other capitals have been modeled spontaneously by natural influence, London is great sample of this approach and was described as a natural city planned over decades by many hands with great appreciation to natural terrain. Contrary mode is obvious in China where several factors behind the distinct identity of Chinese architecture and urban planning. Among those influences are the Metaphysics Philosophies or Emperor guidance who encouraged uniformity in many aspects in China including city planning. The aim of this paper is to highlight the impact of various forces and mankind dogmas in shaping up a unique character of famous capitals. Hence London and Beijing are the two contradictory case studies subject to deep analysis in parallel with other theories such as Yin - Yan and Fengs Shui principles, to examine their impacts on urban planning in China.

  10. New geologic slip rates for the Agua Blanca Fault, northern Baja California, Mexico

    Science.gov (United States)

    Gold, P. O.; Behr, W. M.; Fletcher, J. M.; Hinojosa-Corona, A.; Rockwell, T. K.

    2015-12-01

    Within the southern San Andreas transform plate boundary system, relatively little is known regarding active faulting in northern Baja California, Mexico, or offshore along the Inner Continental Borderland. The inner offshore system appears to be fed from the south by the Agua Blanca Fault (ABF), which strikes northwest across the Peninsular Ranges of northern Baja California. Therefore, the geologic slip rate for the ABF also provides a minimum slip rate estimate for the offshore system, which is connected to the north to faults in the Los Angeles region. Previous studies along the ABF determined slip rates of ~4-6 mm/yr (~10% of relative plate motion). However, these rates relied on imprecise age estimates and offset geomorphic features of a type that require these rates to be interpreted as minima, allowing for the possibility that the slip rate for the ABF may be greater. Although seismically quiescent, the surface trace of the ABF clearly reflects Holocene activity, and given its connectivity with the offshore fault system, more quantitative slip rates for the ABF are needed to better understand earthquake hazard for both US and Mexican coastal populations. Using newly acquired airborne LiDAR, we have mapped primary and secondary fault strands along the segmented western 70 km of the ABF. Minimal development has left the geomorphic record of surface slip remarkably well preserved, and we have identified abundant evidence meter to km scale right-lateral displacement, including new Late Quaternary slip rate sites. We verified potential reconstructions at each site during summer 2015 fieldwork, and selected an initial group of three high potential slip rate sites for detailed mapping and geochronologic analyses. Offset landforms, including fluvial terrace risers, alluvial fans, and incised channel fill deposits, record displacements of ~5-80 m, and based on minimal soil development, none appear older than early Holocene. To quantitatively constrain landform ages

  11. Crimea-Kopet Dagh zone of concentrated orogenic deformations as a transregional late collisional right-lateral strike-slip fault

    Science.gov (United States)

    Patina, I. S.; Leonov, Yu. G.; Volozh, Yu. A.; Kopp, M. L.; Antipov, M. P.

    2017-07-01

    It is shown that the Crimea, Caucasus, and Kopet Dagh fold systems make up a single whole unified by a lithospheric strike-slip fault zone of concentrated dislocations. The strike-slip fault that dissects the sedimentary cover and consolidated crust is rooted in subcrustal layers of the mantle. The notions about strike-slip dislocations in the structure of the Crimea-Kopet Dagh System are considered. Comparative analysis of structure, age, and amplitude of strike-slip fault segments is carried out. The effect of strike-slip faulting on the deep-seated and near-surface structure of the Earth's crust is considered. Based on estimation of strike-slip offsets, the paleogeography of Paleogene basins is refined; their initial contours, which have been disturbed and fragmented by slipping motion strike-slip displacement, have been reconstructed.

  12. Slip casting of thoria-10 mole per cent yttria solid electrolyte

    International Nuclear Information System (INIS)

    Ramanathan, S.; Rao, S.V.K.

    1990-01-01

    One end closed thoria-yttria solid electrolyte have been fabricated by the slip casting technique. A systematic study of the influence of the process parameters on the characteristics of the final bodies has been carried out. Slips of ThO 2 -10 mole % Y 2 O 3 were prepared; their fluidity and castability were studied as a function of concentration, pH and particle size. The bodies were sintered at 2000degC and the physical properties like density and microstructure were evaluated. Slip cast bodies of bulk densities around 95% T.D. with relatively inhomogenous but predominantly fine grained structure could be obtained by optimizing the process variables. (author). 5 figs., 10 refs

  13. Pedestrian fall safety assessments improved understanding on slip resistance measurements and investigations

    CERN Document Server

    Kim, In-Ju

    2017-01-01

    This book examines pedestrian shoe-floor slip resistance from an engineering standpoint in order to better understand friction and wear behavior. This analysis includes an extensive investigation into the surface properties of shoes and flow, and the measurement of dynamic friction and other mechanical and physical aspects of shoe-floor tribology. Lastly, the book proposes a measurement concept for the identification and classification of operational floor surfaces under a range of different conditions. Novel techniques and methods are proposed that can improve the reliability of slip resistance assessments. The current state of knowledge is critically examined and discussed from a tribological perspective, including aspects like friction, wear, lubrication and the mechanical behavior of shoes, floors and their wider environment. Further, the book reports on extensive experimental investigations into the topographical characteristics of shoe and floor surfaces and how they affect slip resistance. Slips result...

  14. In-use product stocks link manufactured capital to natural capital.

    Science.gov (United States)

    Chen, Wei-Qiang; Graedel, T E

    2015-05-19

    In-use stock of a product is the amount of the product in active use. In-use product stocks provide various functions or services on which we rely in our daily work and lives, and the concept of in-use product stock for industrial ecologists is similar to the concept of net manufactured capital stock for economists. This study estimates historical physical in-use stocks of 91 products and 9 product groups and uses monetary data on net capital stocks of 56 products to either approximate or compare with in-use stocks of the corresponding products in the United States. Findings include the following: (i) The development of new products and the buildup of their in-use stocks result in the increase in variety of in-use product stocks and of manufactured capital; (ii) substitution among products providing similar or identical functions reflects the improvement in quality of in-use product stocks and of manufactured capital; and (iii) the historical evolution of stocks of the 156 products or product groups in absolute, per capita, or per-household terms shows that stocks of most products have reached or are approaching an upper limit. Because the buildup, renewal, renovation, maintenance, and operation of in-use product stocks drive the anthropogenic cycles of materials that are used to produce products and that originate from natural capital, the determination of in-use product stocks together with modeling of anthropogenic material cycles provides an analytic perspective on the material linkage between manufactured capital and natural capital.

  15. Condition for the occurrence of phase slip centers in superconducting nanowires under applied current or voltage

    DEFF Research Database (Denmark)

    Michotte, S.; Mátéfi-Tempfli, Stefan; Piraux, L.

    2004-01-01

    Experimental results on the phase slip process in superconducting lead nanowires are presented under two different experimental conditions: constant applied current or constant voltage. Based on these experiments we established a simple model which gives us the condition of the appearance of phase...... slip centers in a quasi-one-dimensional wire. The competition between two relaxations times (relaxation time of the absolute value of the order parameter τ and relaxation time of the phase of the order parameter in the phase slip center τ) governs the phase slip process. Phase slips, as periodic...... oscillations in time of the order parameter, are only possible if the gradient of the phase grows faster than the value of the order parameter in the phase slip center, or equivalently if τ≤ τ....

  16. Simulation of Micro-Channel and Micro-Orifice Flow Using Lattice Boltzmann Method with Langmuir Slip Model

    Directory of Open Access Journals (Sweden)

    A. R. Rahmati

    2016-12-01

    Full Text Available Because of its kinetic nature and computational advantages, the Lattice Boltzmann method (LBM has been well accepted as a useful tool to simulate micro-scale flows. The slip boundary model plays a crucial role in the accuracy of solutions for micro-channel flow simulations. The most used slip boundary condition is the Maxwell slip model. The results of Maxwell slip model are affected by the accommodation coefficient significantly, but there is not an explicitly relationship between properties at wall and accommodation coefficient. In the present wok, Langmuir slip model is used beside LBM to simulate micro-channel and micro-orifice flows. Slip velocity and nonlinear pressure drop profiles are presented as two major effects in such flows. The results are in good agreement with existing results in the literature.

  17. Recent estimates of capital flight

    OpenAIRE

    Claessens, Stijn; Naude, David

    1993-01-01

    Researchers and policymakers have in recent years paid considerable attention to the phenomenon of capital flight. Researchers have focused on four questions: What concept should be used to measure capital flight? What figure for capital flight will emerge, using this measure? Can the occurrence and magnitude of capital flight be explained by certain (economic) variables? What policy changes can be useful to reverse capital flight? The authors focus strictly on presenting estimates of capital...

  18. How to invest in social capital.

    Science.gov (United States)

    Prusak, L; Cohen, D

    2001-06-01

    Business runs better when people within a company have close ties and trust one another. But the relationships that make organizations work effectively are under assault for several reasons. Building such "social capital" is difficult in volatile times. Disruptive technologies spawn new markets daily, and organizations respond with constantly changing structures. The problem is worsened by the virtuality of many of today's workplaces, with employees working off-site or on their own. What's more, few managers know how to invest in such social capital. The authors describe how managers can help their organizations thrive by making effective investments in social capital. For instance, companies that value social capital demonstrate a commitment to retention as a way of limiting workplace volatility. The authors cite SAS's extensive efforts to signal to employees that it sees them as human beings, not just workers. Managers can build trust by showing trust themselves, as well as by rewarding trust and sending clear signals to employees. They can foster cooperation by giving employees a common sense of purpose through good strategic communication and inspirational leadership. Johnson & Johnson's well-known credo, which says the company's first responsibility is to the people who use its products, has helped the company in time of adversity, as in 1982 when cyanide in Tylenol capsules killed seven people. Other methods of fostering cooperation include rewarding the behavior with cash and establishing rules that get people into the habit of cooperating. Social capital, once a given in organizations, is now rare and endangered. By investing in it, companies will be better positioned to seize the opportunities in today's volatile, virtual business environment.

  19. Slip reactivation during the 2011 Tohoku earthquake: Dynamic rupture and ground motion simulations

    Science.gov (United States)

    Galvez, P.; Dalguer, L. A.

    2013-12-01

    The 2011 Mw9 Tohoku earthquake generated such as vast geophysical data that allows studying with an unprecedented resolution the spatial-temporal evolution of the rupture process of a mega thrust event. Joint source inversion of teleseismic, near-source strong motion and coseismic geodetic data , e.g [Lee et. al, 2011], reveal an evidence of slip reactivation process at areas of very large slip. The slip of snapshots of this source model shows that after about 40 seconds the big patch above to the hypocenter experienced an additional push of the slip (reactivation) towards the trench. These two possible repeating slip exhibited by source inversions can create two waveform envelops well distinguished in the ground motion pattern. In fact seismograms of the KiK-Net Japanese network contained this pattern. For instance a seismic station around Miyagi (MYGH10) has two main wavefronts separated between them by 40 seconds. A possible physical mechanism to explain the slip reactivation could be a thermal pressurization process occurring in the fault zone. In fact, Kanamori & Heaton, (2000) proposed that for large earthquakes frictional melting and fluid pressurization can play a key role of the rupture dynamics of giant earthquakes. If fluid exists in a fault zone, an increase of temperature can rise up the pore pressure enough to significantly reduce the frictional strength. Therefore, during a large earthquake the areas of big slip persuading strong thermal pressurization may result in a second drop of the frictional strength after reaching a certain value of slip. Following this principle, we adopt for slip weakening friction law and prescribe a certain maximum slip after which the friction coefficient linearly drops down again. The implementation of this friction law has been done in the latest unstructured spectral element code SPECFEM3D, Peter et. al. (2012). The non-planar subduction interface has been taken into account and place on it a big asperity patch inside

  20. Simulating the Evolving Behavior of Secondary Slow Slip Fronts

    Science.gov (United States)

    Peng, Y.; Rubin, A. M.

    2017-12-01

    High-resolution tremor catalogs of slow slip events reveal secondary slow slip fronts behind the main front that repetitively occupy the same source area during a single episode. These repetitive fronts are most often observed in regions with high tremor density. Their recurrence intervals gradually increase from being too short to be tidally modulated (tens of minutes) to being close to tidal periods (about 12 or 24 hours). This could be explained by a decreasing loading rate from creep in the surrounding regions (with few or no observable tremor events) as the main front passes by. As the recurrence intervals of the fronts increase, eventually they lock in on the tidal periods. We attempt to simulate this numerically using a rate-and-state friction law that transitions from velocity-weakening at low slip speeds to velocity strengthening at high slip speeds. Many small circular patches with a cutoff velocity an order of magnitude higher than that of the background are randomly placed on the fault, in order to simulate the average properties of the high-density tremor zone. Preliminary results show that given reasonable parameters, this model produces similar propagation speeds of the forward-migrating main front inside and outside the high-density tremor zone, consistent with observations. We will explore the behavior of the secondary fronts that arise in this model, in relation to the local density of the small tremor-analog patches, the overall geometry of the tremor zone and the tides.

  1. Severe hypoglycaemia during treatment with sulphonylureas in patients with type 2 diabetes in the Capital Region of Denmark

    DEFF Research Database (Denmark)

    Pilemann-Lyberg, S; Thorsteinsson, B; Snorgaard, O

    2015-01-01

    AIMS: Sulphonylureas (SU) are currently recommended as a well-established second line treatment in guidelines for type 2 diabetes (T2DM). In the Capital Region of Denmark 16,865 patients were given SU as part of their treatment of T2DM in 2010-2011. To what extent SU are associated...... with hospitalizations due to severe hypoglycaemic episodes, defined as episodes with a need for external assistance, was investigated. The prevalence and characteristics of these patients and potential risk factors were studied. METHODS: ICD-10 diagnosis codes were used to identify patients hospitalized due...... to hypoglycaemia and T2DM for a period of 2 years (2010-2011). Inclusion criteria were T2DM, hospitalization due to hypoglycaemia and treatment with SU as monotherapy or in combination with other glucose-lowering drugs except insulin treatment. RESULTS: We identified 161 patients fulfilling the inclusion criteria...

  2. Financial Frictions and the Credit Transmission Channel: Capital Requirements and Bank Capital

    OpenAIRE

    Lucyna Gornicka; Sweder van Wijnbergen

    2013-01-01

    We investigate actual capital chosen by banks in presence of capital minimum requirements and ex-post penalties for violating them. The model yields excess capital that is always positive and increases during times of distress in the economy, which is in line with empirical evidence. Next, we show that in presence of ex-post violation penalties the introduction of the conservation buffer under Basel III will not contribute to lowering the pro-cyclicality of capital regulations. The countercyc...

  3. Shear Slip Potential Induced by Thermomechanical Loading in an Underground Repository for Nuclear Waste

    International Nuclear Information System (INIS)

    Lee, Jaewon; Min, Kibok; Stephansson, Ove

    2010-01-01

    In the context of a deep geological repository for nuclear water, the thermal stress generated by nuclear waster is expected to contribute to shear slip and dilation, which will eventually alter the fracture permeability in the region. In this study, the probability of the occurrence of shear slip at a fracture was examined by the Mohr-Coulomb failure criterion. The study was based on the fracture orientation generated by the Latin hypercube sampling method, which can improve the efficiency of Monte Carlo simulations by the use of a more systematic approach for selecting the input samples. Statistical data of fracture orientations from the site investigation in Forsmark, Sweden, were used in this study. The historical assessment of thermal stress was based on three-dimensional finite element modeling of a geological repository that measures 800 m by 2000 m and on a time scale up to 10,000 years. The results show that the probability of shear slip evolved differently at six selected points due to the difference stresses at each point. However, it was evident that the probability of shear slip was more that twice as large as the initial probability of failure. This increased permeability and micro seismicity, which can be an issue during the initial operation of the repository. The study provided a quantitative assessment of the probability of shear slip at a fracture, which is an important parameter for assessing the performance of a geological repository. Conclusions are summarized as follows: · With random orientation data, the probability of shear slip around the repository model increases with increased thermal stress. · The probability of shear slip depends on the manner in which the thermal stress is generated. Higher shear slip is expected with higher differential thermal stress. · The probability of shear slip at Forsmark was less than 1 %. If different sites have fracture sets with more overlap, however, the probability may become increase. Therefore, a

  4. The Role of Near-Fault Relief in Creating and Maintaining Strike-Slip Landscape Features

    Science.gov (United States)

    Harbert, S.; Duvall, A. R.; Tucker, G. E.

    2016-12-01

    Geomorphic landforms, such as shutter ridges, offset river terraces, and deflected stream channels, are often used to assess the activity and slip rates of strike-slip faults. However, in some systems, such as parts of the Marlborough Fault System (South Island, NZ), an active strike-slip fault does not leave a strong landscape signature. Here we explore the factors that dampen or enhance the landscape signature of strike-slip faulting using the Channel-Hillslope Integrated Landscape Development model (CHILD). We focus on variables affecting the length of channel offsets, which enhance the signature of strike-slip motion, and the frequency of stream captures, which eliminate offsets and reduce this signature. We model a strike-slip fault that passes through a mountain ridge, offsetting streams that drain across this fault. We use this setup to test the response of channel offset length and capture frequency to fault characteristics, such as slip rate and ratio of lateral to vertical motion, and to landscape characteristics, such as relief contrasts controlled by erodibility. Our experiments show that relief downhill of the fault, whether generated by differential uplift across the fault or by an erodibility contrast, has the strongest effect on offset length and capture frequency. This relief creates shutter ridges, which block and divert streams while being advected along a fault. Shutter ridges and the streams they divert have long been recognized as markers of strike-slip motion. Our results show specifically that the height of shutter ridges is most responsible for the degree to which they create long channel offsets by preventing stream captures. We compare these results to landscape metrics in the Marlborough Fault System, where shutter ridges are common and often lithologically controlled. We compare shutter ridge length and height to channel offset length in order to assess the influence of relief on offset channel features in a real landscape. Based on our

  5. An improved particle population balance equation in the continuum-slip regime

    Directory of Open Access Journals (Sweden)

    Xie Mingliang

    2016-01-01

    Full Text Available An improved moment model is proposed to solve the population balance equation for Brownian coagulation in the continuum-slip regime, and it reduces to a known one in open literature when the non-linear terms in the slip correction factor are ignored. The present model shows same asymptotic behavior as that in the continuum regime.

  6. On a credit oscillatory system with the inclusion of stick-slip

    Directory of Open Access Journals (Sweden)

    Parovik Roman

    2016-01-01

    Full Text Available The work was a mathematical model that describes the effect of the sliding attachment (stick-slip, taking into account hereditarity. This model can be regarded as a mechanical model of earthquake preparation. For such a model was proposed explicit finite- difference scheme, on which were built the waveform and phase trajectories hereditarity effect of stick-slip.

  7. Strike-slip tectonics during rift linkage

    Science.gov (United States)

    Pagli, C.; Yun, S. H.; Ebinger, C.; Keir, D.; Wang, H.

    2017-12-01

    The kinematics of triple junction linkage and the initiation of transforms in magmatic rifts remain debated. Strain patterns from the Afar triple junction provide tests of current models of how rifts grow to link in area of incipient oceanic spreading. Here we present a combined analysis of seismicity, InSAR and GPS derived strain rate maps to reveal that the plate boundary deformation in Afar is accommodated primarily by extensional tectonics in the Red Sea and Gulf of Aden rifts, and does not require large rotations about vertical axes (bookshelf faulting). Additionally, models of stress changes and seismicity induced by recent dykes in one sector of the Afar triple junction provide poor fit to the observed strike-slip earthquakes. Instead we explain these patterns as rift-perpendicular shearing at the tips of spreading rifts where extensional strains terminate against less stretched lithosphere. Our results demonstrate that rift-perpendicular strike-slip faulting between rift segments achieves plate boundary linkage during incipient seafloor spreading.

  8. Capital Structure Policies in Europe: Survey Evidence

    NARCIS (Netherlands)

    D. Brounen (Dirk); A. de Jong (Abe); C.G. Koedijk (Kees)

    2005-01-01

    textabstractIn this paper we present the results of an international survey among 313 CFOs on capital structure choice. We document several interesting insights on how theoretical concepts are being applied by professionals in the U.K., the Netherlands, Germany, and France and we directly compare

  9. Steady Boundary Layer Slip Flow along with Heat and Mass Transfer over a Flat Porous Plate Embedded in a Porous Medium

    Science.gov (United States)

    Aziz, Asim; Siddique, J. I.; Aziz, Taha

    2014-01-01

    In this paper, a simplified model of an incompressible fluid flow along with heat and mass transfer past a porous flat plate embedded in a Darcy type porous medium is investigated. The velocity, thermal and mass slip conditions are utilized that has not been discussed in the literature before. The similarity transformations are used to transform the governing partial differential equations (PDEs) into a nonlinear ordinary differential equations (ODEs). The resulting system of ODEs is then reduced to a system of first order differential equations which was solved numerically by using Matlab bvp4c code. The effects of permeability, suction/injection parameter, velocity parameter and slip parameter on the structure of velocity, temperature and mass transfer rates are examined with the aid of several graphs. Moreover, observations based on Schmidt number and Soret number are also presented. The result shows, the increase in permeability of the porous medium increase the velocity and decrease the temperature profile. This happens due to a decrease in drag of the fluid flow. In the case of heat transfer, the increase in permeability and slip parameter causes an increase in heat transfer. However for the case of increase in thermal slip parameter there is a decrease in heat transfer. An increase in the mass slip parameter causes a decrease in the concentration field. The suction and injection parameter has similar effect on concentration profile as for the case of velocity profile. PMID:25531301

  10. Steady boundary layer slip flow along with heat and mass transfer over a flat porous plate embedded in a porous medium.

    Science.gov (United States)

    Aziz, Asim; Siddique, J I; Aziz, Taha

    2014-01-01

    In this paper, a simplified model of an incompressible fluid flow along with heat and mass transfer past a porous flat plate embedded in a Darcy type porous medium is investigated. The velocity, thermal and mass slip conditions are utilized that has not been discussed in the literature before. The similarity transformations are used to transform the governing partial differential equations (PDEs) into a nonlinear ordinary differential equations (ODEs). The resulting system of ODEs is then reduced to a system of first order differential equations which was solved numerically by using Matlab bvp4c code. The effects of permeability, suction/injection parameter, velocity parameter and slip parameter on the structure of velocity, temperature and mass transfer rates are examined with the aid of several graphs. Moreover, observations based on Schmidt number and Soret number are also presented. The result shows, the increase in permeability of the porous medium increase the velocity and decrease the temperature profile. This happens due to a decrease in drag of the fluid flow. In the case of heat transfer, the increase in permeability and slip parameter causes an increase in heat transfer. However for the case of increase in thermal slip parameter there is a decrease in heat transfer. An increase in the mass slip parameter causes a decrease in the concentration field. The suction and injection parameter has similar effect on concentration profile as for the case of velocity profile.

  11. Analytical method for determining breakdown slip of an induction motor based on of five parameters

    Directory of Open Access Journals (Sweden)

    Petrović Nenad

    2014-01-01

    Full Text Available The paper proposes an explicite formula for determining the critical slip value of an induction squirel cage motor based upon five parameters. Three of these parameters - rated slip, rated and breakdown torque are known by catalogue data. Two missing parameters are the arbitrary slip between the rated and critical slip value and the corresponding torque value. These two parameters are to be experimentaly obtained. The breakdown torque value given by catalogue data is usually less accurate than the rated torque value. The proposed formula gives the possibility of analysing the error distribution of the critical slip value obtained from catalogue and measured data in comparison with the values obtained from the mechanical characteristic based on the physical parameters of an induction motor.

  12. Creep and slip: Seismic precursors to the Nuugaatsiaq landslide (Greenland)

    Science.gov (United States)

    Poli, Piero

    2017-09-01

    Precursory signals to material's failure are predicted by numerical models and observed in laboratory experiments or using field data. These precursory signals are a marker of slip acceleration on weak regions, such as crustal faults. Observation of these precursory signals of catastrophic natural events, such as earthquakes and landslides, is necessary for improving our knowledge about the physics of the nucleation process. Furthermore, observing such precursory signals may help to forecast these catastrophic events or reduce their hazard. I report here the observation of seismic precursors to the Nuugaatsiaq landslide in Greenland. Time evolution of the detected precursors implies that an aseismic slip event is taking place for hours before the landslide, with an exponential increase of slip velocity. Furthermore, time evolution of the precursory signals' amplitude sheds light on the evolution of the fault physics during the nucleation process.

  13. Cultural Capital in Context: Heterogeneous Returns to Cultural Capital Across Schooling Environments

    DEFF Research Database (Denmark)

    Andersen, Ida Gran; Jæger, Mads Meier

    2015-01-01

    This paper tests two competing explanations of differences in returns to cultural capital across schooling environments: Cultural reproduction (cultural capital yields a higher returns in high-achieving environments than in low-achieving ones) and cultural mobility (cultural capital yields higher...... returns in low-achieving environments). Using multilevel mixture models, empirical results from analyses based on PISA data from three countries (Canada, Germany, and Sweden) show that returns to cultural capital tend to be higher in low-achieving schooling environments than in high-achieving ones....... These results principally support the cultural mobility explanation and suggest that research should pay explicit attention to the institutional contexts in which cultural capital is converted into educational success....

  14. Implications of basal micro-earthquakes and tremor for ice stream mechanics: Stick-slip basal sliding and till erosion

    Science.gov (United States)

    Barcheck, C. Grace; Tulaczyk, Slawek; Schwartz, Susan Y.; Walter, Jacob I.; Winberry, J. Paul

    2018-03-01

    The Whillans Ice Plain (WIP) is unique among Antarctic ice streams because it moves by stick-slip. The conditions allowing stick-slip and its importance in controlling ice dynamics remain uncertain. Local basal seismicity previously observed during unstable slip is a clue to the mechanism of ice stream stick-slip and a window into current basal conditions, but the spatial extent and importance of this basal seismicity are unknown. We analyze data from a 2010-2011 ice-plain-wide seismic and GPS network to show that basal micro-seismicity correlates with large-scale patterns in ice stream slip behavior: Basal seismicity is common where the ice moves the least between unstable slip events, with small discrete basal micro-earthquakes happening within 10s of km of the central stick-slip nucleation area and emergent basal tremor occurring downstream of this area. Basal seismicity is largely absent in surrounding areas, where inter-slip creep rates are high. The large seismically active area suggests that a frictional sliding law that can accommodate stick-slip may be appropriate for ice stream beds on regional scales. Variability in seismic behavior over inter-station distances of 1-10 km indicates heterogeneity in local bed conditions and frictional complexity. WIP unstable slips may nucleate when stick-slip basal earthquake patches fail over a large area. We present a conceptual model in which basal seismicity results from slip-weakening frictional failure of over-consolidated till as it is eroded and mobilized into deforming till.

  15. Development of a slip sensor using separable bilayer with Ecoflex-NBR film

    Science.gov (United States)

    Kim, Sung Joon; Moon, Hyungpil; Choi, Hyouk Ryeol; Koo, Ja Choon

    2017-04-01

    Polymer film-type slip sensor is presented by using novel working principle rather than measuring micro-vibration. The sensor is comprised of bilayer with Ecoflex and NBR(acrylonitrile butadiene rubber) films divided by di-electric. When slip occur on surface, bilayer have relative displacement from each other because friction-induced vibration make a clearance between two layers. This displacement can be obtained by capacitance difference. CNT(carbon nanotube) was employed for electrode because of flexible and stretchable characteristics. Also normal and shear force can be decoupled by the working principle. To verify developed sensor, slip test apparatus was designed and experiments were conducted.

  16. MHD Boundary Layer Slip Flow and Heat Transfer over a Flat Plate

    International Nuclear Information System (INIS)

    Bhattacharyya, Krishnendu; Mukhopadhyay, Swati; Layek, G. C.

    2011-01-01

    An analysis of magnetohydrodynamic (MHD) boundary layer flow and heat transfer over a flat plate with slip condition at the boundary is presented. A complete self-similar set of equations are obtained from the governing equations using similarity transformations and are solved by a shooting method. In the boundary slip condition no local similarity occurs. Velocity and temperature distributions within the boundary layer are presented. Our analysis reveals that the increase of magnetic and slip parameters reduce the boundary layer thickness and also enhance the heat transfer from the plate. (fundamental areas of phenomenology(including applications))

  17. Radar Determination of Fault Slip and Location in Partially Decorrelated Images

    Science.gov (United States)

    Parker, Jay; Glasscoe, Margaret; Donnellan, Andrea; Stough, Timothy; Pierce, Marlon; Wang, Jun

    2017-06-01

    Faced with the challenge of thousands of frames of radar interferometric images, automated feature extraction promises to spur data understanding and highlight geophysically active land regions for further study. We have developed techniques for automatically determining surface fault slip and location using deformation images from the NASA Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), which is similar to satellite-based SAR but has more mission flexibility and higher resolution (pixels are approximately 7 m). This radar interferometry provides a highly sensitive method, clearly indicating faults slipping at levels of 10 mm or less. But interferometric images are subject to decorrelation between revisit times, creating spots of bad data in the image. Our method begins with freely available data products from the UAVSAR mission, chiefly unwrapped interferograms, coherence images, and flight metadata. The computer vision techniques we use assume no data gaps or holes; so a preliminary step detects and removes spots of bad data and fills these holes by interpolation and blurring. Detected and partially validated surface fractures from earthquake main shocks, aftershocks, and aseismic-induced slip are shown for faults in California, including El Mayor-Cucapah (M7.2, 2010), the Ocotillo aftershock (M5.7, 2010), and South Napa (M6.0, 2014). Aseismic slip is detected on the San Andreas Fault from the El Mayor-Cucapah earthquake, in regions of highly patterned partial decorrelation. Validation is performed by comparing slip estimates from two interferograms with published ground truth measurements.

  18. Parametric analysis of the statistical model of the stick-slip process

    Science.gov (United States)

    Lima, Roberta; Sampaio, Rubens

    2017-06-01

    In this paper it is performed a parametric analysis of the statistical model of the response of a dry-friction oscillator. The oscillator is a spring-mass system which moves over a base with a rough surface. Due to this roughness, the mass is subject to a dry-frictional force modeled as a Coulomb friction. The system is stochastically excited by an imposed bang-bang base motion. The base velocity is modeled by a Poisson process for which a probabilistic model is fully specified. The excitation induces in the system stochastic stick-slip oscillations. The system response is composed by a random sequence alternating stick and slip-modes. With realizations of the system, a statistical model is constructed for this sequence. In this statistical model, the variables of interest of the sequence are modeled as random variables, as for example, the number of time intervals in which stick or slip occur, the instants at which they begin, and their duration. Samples of the system response are computed by integration of the dynamic equation of the system using independent samples of the base motion. Statistics and histograms of the random variables which characterize the stick-slip process are estimated for the generated samples. The objective of the paper is to analyze how these estimated statistics and histograms vary with the system parameters, i.e., to make a parametric analysis of the statistical model of the stick-slip process.

  19. Cultural Capital in Context:

    DEFF Research Database (Denmark)

    Andersen, Ida Gran; Jæger, Mads Meier

    This paper analyzes the extent to which the effect of cultural capital on academic achievement varies across high- and low-achieving schooling environments. We distinguish three competing theoretical models: Cultural reproduction (cultural capital yields higher returns in high-achieving schooling...... to be higher in low-achieving schooling environments than in high-achieving ones. These results support the cultural mobility explanation and are in line with previous research suggesting that children from low-SES families benefit more from cultural capital than children from high-SES families....... environments than in low-achieving ones), cultural mobility (cultural capital yields higher returns in low-achieving environments), and cultural resources (cultural capital yields the same returns in different environments). We analyze PISA data from six countries and find that returns to cultural capital tend...

  20. Does fault strengthening in laboratory rock friction experiments really depend primarily upon time and not slip?

    Science.gov (United States)

    Bhattacharya, Pathikrit; Rubin, Allan M.; Beeler, Nicholas M.

    2017-08-01

    The popular constitutive formulations of rate-and-state friction offer two end-member views on whether friction evolves only with slip (Slip law) or with time even without slip (Aging law). While rate stepping experiments show support for the Slip law, laboratory-observed frictional behavior near-zero slip rates has traditionally been inferred as supporting Aging law style time-dependent healing, in particular, from the slide-hold-slide experiments of Beeler et al. (1994). Using a combination of new analytical results and explicit numerical (Bayesian) inversion, we show instead that the slide-hold-slide data of Beeler et al. (1994) favor slip-dependent state evolution during holds. We show that, while the stiffness-independent rate of growth of peak stress (following reslides) with hold duration is a property shared by both the Aging and (under a more restricted set of parameter combinations) Slip laws, the observed stiffness dependence of the rate of stress relaxation during long holds is incompatible with the Aging law with constant rate-state parameters. The Slip law consistently fits the evolution of the stress minima at the end of the holds well, whether fitting jointly with peak stresses or otherwise. But neither the Aging nor Slip laws fit all the data well when a - b is constrained to values derived from prior velocity steps. We also attempted to fit the evolution of stress peaks and minima with the Kato-Tullis hybrid law and the shear stress-dependent Nagata law, both of which, even with the freedom of an extra parameter, generally reproduced the best Slip law fits to the data.

  1. Smoothing of Fault Slip Surfaces by Scale Invariant Wear

    Science.gov (United States)

    Dascher-Cousineau, K.; Kirkpatrick, J. D.

    2017-12-01

    Fault slip surface roughness plays a determining role in the overall strength, friction, and dynamic behavior of fault systems. Previous wear models and field observations suggest that roughness decreases with increasing displacement. However, measurements have yet to isolate the effect of displacement from other possible controls, such as lithology or tectonic setting. In an effort to understand the effect of displacement, we present comprehensive qualitative and quantitative description of the evolution of fault slip surfaces in and around the San-Rafael Desert, S.E. Utah, United States. In the study area, faults accommodated regional extension at shallow (1 to 3 km) depth and are hosted in the massive, well-sorted, high-porosity Navajo and Entrada sandstones. Existing displacement profiles along with tight displacement controls readily measureable in the field, combined with uniform lithology and tectonic history, allowed us to isolate for the effect of displacement during the embryonic stages of faulting (0 to 60 m in displacement). Our field observations indicate a clear compositional and morphological progression from isolated joints or deformation bands towards smooth, continuous, and mirror-like fault slip surfaces with increasing displacement. We scanned pristine slip surfaces with a white light interferometer, a laser scanner, and a ground-based LiDAR. We produce and analyses more than 120 individual scans of fault slip surfaces. Results for the surfaces with the best displacement constraints indicate that roughness as defined by the power spectral density at any given length scale decreases with displacement according to a power law with an exponent of -1. Roughness measurements associated with only maximum constraints on displacements corroborate this result. Moreover, maximum roughness for any given fault is bounded by a primordial roughness corresponding to that of joint surfaces and deformation band edges. Building upon these results, we propose a

  2. Human capital diversity in the creation of social capital for team creativity

    NARCIS (Netherlands)

    Han, J.; Han, J; Brass, D.

    2014-01-01

    We highlight the social aspects of team creativity by proposing that team creativity is influenced by two types of team social capital: bridging and bonding social capital. Going beyond the structural perspective, we posit that team-level human capital diversity is one of the potential antecedents

  3. Preventing slips and falls through leisure-time physical activity: findings from a study of limited-service restaurants.

    Directory of Open Access Journals (Sweden)

    Alberto J Caban-Martinez

    Full Text Available Physical activity has been shown to be beneficial at improving health in some medical conditions and in preventing injury. Epidemiologic studies suggest that physical activity is one factor associated with a decreased risk for slips and falls in the older (≥ 65 years adult population. While the risk of slips and falls is generally lower in younger than in older adults; little is known of the relative contribution of physical activity in preventing slips and falls in younger adults. We examined whether engagement in leisure-time physical activity (LTPA was protective of slips and falls among a younger/middle-aged (≤ 50 years old working population.475 workers from 36 limited-service restaurants in six states in the U.S. were recruited to participate in a prospective cohort study of workplace slipping. Information on LTPA was collected at the time of enrollment. Participants reported their slip experience and work hours weekly for up to 12 weeks. We investigated the association between the rate of slipping and the rate of major slipping (i.e., slips that resulted in a fall and/or injury and LTPA for workers 50 years of age and younger (n = 433, range 18-50 years old using a multivariable negative binomial generalized estimating equation model.The rate of major slips among workers who engaged in moderate (Adjusted Rate Ratio (RR  = 0.65; 95% Confidence Interval (CI  =  [0.18-2.44] and vigorous (RR = 0.64; 95%CI  =  [0.18-2.26] LTPA, while non-significant, were approximately one-third lower than the rate of major slips among less active workers.While not statistically significant, the results suggest a potential association between engagement in moderate and vigorous LTPA and the rate of major slips in younger adults. Additional studies that examine the role of occupational and non-occupational physical activity on the risk of slips, trips and falls among younger and middle aged adults appear warranted.

  4. Finite element models of earthquake cycles in mature strike-slip fault zones

    Science.gov (United States)

    Lynch, John Charles

    The research presented in this dissertation is on the subject of strike-slip earthquakes and the stresses that build and release in the Earth's crust during earthquake cycles. Numerical models of these cycles in a layered elastic/viscoelastic crust are produced using the finite element method. A fault that alternately sticks and slips poses a particularly challenging problem for numerical implementation, and a new contact element dubbed the "Velcro" element was developed to address this problem (Appendix A). Additionally, the finite element code used in this study was bench-marked against analytical solutions for some simplified problems (Chapter 2), and the resolving power was tested for the fault region of the models (Appendix B). With the modeling method thus developed, there are two main questions posed. First, in Chapter 3, the effect of a finite-width shear zone is considered. By defining a viscoelastic shear zone beneath a periodically slipping fault, it is found that shear stress concentrates at the edges of the shear zone and thus causes the stress tensor to rotate into non-Andersonian orientations. Several methods are used to examine the stress patterns, including the plunge angles of the principal stresses and a new method that plots the stress tensor in a manner analogous to seismic focal mechanism diagrams. In Chapter 4, a simple San Andreas-like model is constructed, consisting of two great earthquake producing faults separated by a freely-slipping shorter fault. The model inputs of lower crustal viscosity, fault separation distance, and relative breaking strengths are examined for their effect on fault communication. It is found that with a lower crustal viscosity of 1018 Pa s (in the lower range of estimates for California), the two faults tend to synchronize their earthquake cycles, even in the cases where the faults have asymmetric breaking strengths. These models imply that postseismic stress transfer over hundreds of kilometers may play a

  5. Velocity slip and translational nonequilibrium of ternary gas mixtures in free jet expansions

    International Nuclear Information System (INIS)

    Cattolica, R.J.; Gallagher, R.J.; Anderson, J.B.; Talbot, L.

    1977-05-01

    An aerodynamic isotope separation technique based on the velocity slip between gases in a rarefied flow has been proposed. To evaluate the efficiency of this separation technique, the velocity and translational temperature of the individual species in binary and ternary gas mixtures of argon and neon in helium have been studied in a low density hypersonic free jet. The velocity and temperature of the gas were determined from the Doppler shift and broadening of the fluorescence excited by an electron beam. Velocity slip and translational nonequilibrium were observed over a range of source pressures. A separation factor based on the velocity slip and temperatures was also determined. A comparison of the velocity slip, temperatures, and separation factor with the results of a Monte Carlo simulation of the flow field is presented

  6. Slip Torque Investigation and Magnetic Redesign of Motor Integrated Permanent Magnet Gear

    DEFF Research Database (Denmark)

    Frandsen, Tommy Vestergaard; Rasmussen, Peter Omand

    2015-01-01

    This paper presents an investigation of 20% difference between the measured and calculated slip torque of a Motor Integrated Permanent Magnet Gear (MIPMG) prototype. The High Speed (HS) side of the Magnetic Gear (MG) was fixed by loading the motor when conducting the slip torque measurement. Susp...

  7. Revealing the cluster of slow transients behind a large slow slip event.

    Science.gov (United States)

    Frank, William B; Rousset, Baptiste; Lasserre, Cécile; Campillo, Michel

    2018-05-01

    Capable of reaching similar magnitudes to large megathrust earthquakes [ M w (moment magnitude) > 7], slow slip events play a major role in accommodating tectonic motion on plate boundaries through predominantly aseismic rupture. We demonstrate here that large slow slip events are a cluster of short-duration slow transients. Using a dense catalog of low-frequency earthquakes as a guide, we investigate the M w 7.5 slow slip event that occurred in 2006 along the subduction interface 40 km beneath Guerrero, Mexico. We show that while the long-period surface displacement, as recorded by Global Positioning System, suggests a 6-month duration, the motion in the direction of tectonic release only sporadically occurs over 55 days, and its surface signature is attenuated by rapid relocking of the plate interface. Our proposed description of slow slip as a cluster of slow transients forces us to re-evaluate our understanding of the physics and scaling of slow earthquakes.

  8. Monte Carlo simulation for slip rate sensitivity analysis in Cimandiri fault area

    Energy Technology Data Exchange (ETDEWEB)

    Pratama, Cecep, E-mail: great.pratama@gmail.com [Graduate Program of Earth Science, Faculty of Earth Science and Technology, ITB, JalanGanesa no. 10, Bandung 40132 (Indonesia); Meilano, Irwan [Geodesy Research Division, Faculty of Earth Science and Technology, ITB, JalanGanesa no. 10, Bandung 40132 (Indonesia); Nugraha, Andri Dian [Global Geophysical Group, Faculty of Mining and Petroleum Engineering, ITB, JalanGanesa no. 10, Bandung 40132 (Indonesia)

    2015-04-24

    Slip rate is used to estimate earthquake recurrence relationship which is the most influence for hazard level. We examine slip rate contribution of Peak Ground Acceleration (PGA), in probabilistic seismic hazard maps (10% probability of exceedance in 50 years or 500 years return period). Hazard curve of PGA have been investigated for Sukabumi using a PSHA (Probabilistic Seismic Hazard Analysis). We observe that the most influence in the hazard estimate is crustal fault. Monte Carlo approach has been developed to assess the sensitivity. Then, Monte Carlo simulations properties have been assessed. Uncertainty and coefficient of variation from slip rate for Cimandiri Fault area has been calculated. We observe that seismic hazard estimates is sensitive to fault slip rate with seismic hazard uncertainty result about 0.25 g. For specific site, we found seismic hazard estimate for Sukabumi is between 0.4904 – 0.8465 g with uncertainty between 0.0847 – 0.2389 g and COV between 17.7% – 29.8%.

  9. On exact solutions for oscillatory flows in a generalized Burgers fluid with slip condition

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, Tasawar [Dept. of Mathematics, Quaid-i-Azam Univ., Islamabad (Pakistan); Dept. of Mathematics, Coll. of Sciences, KS Univ., Riyadh (Saudi Arabia); Najam, Saher [Theoretical Plasma Physics Div., PINSTECH, P.O. Nilore, Islamabad (Pakistan); Sajid, Muhammad; Mesloub, Said [Dept. of Mathematics, Coll. of Sciences, KS Univ., Riyadh (Saudi Arabia); Ayub, Muhammad [Dept. of Mathematics, Quaid-i-Azam Univ., Islamabad (Pakistan)

    2010-05-15

    An analysis is performed for the slip effects on the exact solutions of flows in a generalized Burgers fluid. The flow modelling is based upon the magnetohydrodynamic (MHD) nature of the fluid and modified Darcy law in a porous space. Two illustrative examples of oscillatory flows are considered. The results obtained are compared with several limiting cases. It has been shown here that the derived results hold for all values of frequencies including the resonant frequency. (orig.)

  10. KONTRIBUSI HUMAN CAPITAL dan CUSTOMER CAPITAL DALAM MENGGAPAI KINERJA CAFÉ dan RESTO di SURABAYA

    Directory of Open Access Journals (Sweden)

    Gendut Sukarno

    2016-11-01

    Berdasarkan hasil pengolahan data diketemukan bahwa 1 human capital mampu memberikan kontribusi yang berarti terhadap customer capital. 2 Customer capital mampu memberikan kontribusi yang berarti terhadap kinerja café dan resto di Surabaya, 3 human capital mampu memberikan kontribusi yang berarti terhadap kinerja café dan resto di Surabaya.

  11. Cultural capital in context: heterogeneous returns to cultural capital across schooling environments.

    Science.gov (United States)

    Andersen, Ida Gran; Jæger, Mads Meier

    2015-03-01

    This paper tests two competing explanations of differences in returns to cultural capital across schooling environments: Cultural reproduction (cultural capital yields a higher returns in high-achieving environments than in low-achieving ones) and cultural mobility (cultural capital yields higher returns in low-achieving environments). Using multilevel mixture models, empirical results from analyses based on PISA data from three countries (Canada, Germany, and Sweden) show that returns to cultural capital tend to be higher in low-achieving schooling environments than in high-achieving ones. These results principally support the cultural mobility explanation and suggest that research should pay explicit attention to the institutional contexts in which cultural capital is converted into educational success. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Instrument for analysis of electric motors based on slip-poles component

    Science.gov (United States)

    Haynes, Howard D.; Ayers, Curtis W.; Casada, Donald A.

    1996-01-01

    A new instrument for monitoring the condition and speed of an operating electric motor from a remote location. The slip-poles component is derived from a motor current signal. The magnitude of the slip-poles component provides the basis for a motor condition monitor, while the frequency of the slip-poles component provides the basis for a motor speed monitor. The result is a simple-to-understand motor health monitor in an easy-to-use package. Straightforward indications of motor speed, motor running current, motor condition (e.g., rotor bar condition) and synthesized motor sound (audible indication of motor condition) are provided. With the device, a relatively untrained worker can diagnose electric motors in the field without requiring the presence of a trained engineer or technician.

  13. An appraisal of subcooled boiling and slip ratio from measurements made in Lingen BWR

    International Nuclear Information System (INIS)

    Nash, G.

    1977-08-01

    Measurements of steam bubble velocities and voidage have been made in the relatively small Core B of Lingen BWR. The results of axial scanning in one radial position have produced experimental values of slip ratio, power (from a travelling incore probe), voidage and coolant mean density over the core height for this position. This one set of distributions has enabled us to test current UKAEA models of subcooled boiling and slip ratio against experiment. From the comparisons, it appears that we can predict the onset of voiding well, but the assumption that a constant fraction of the heat flux forms steam in the subcooled region needs modifying. Of four slip options tested, the current one used by HAMBO and JOSHUA III (Bankoff-Jones) predicts too high a slip ratio. A closer fit to experiment comes from the new Bryce flow-dependent slip option. Any changes in the modelling must be checked, however, with coupled thermal hydraulics-neutronics computations. (author)

  14. Stokes drag on a disc with a Navier slip condition near a plane wall

    International Nuclear Information System (INIS)

    Sherwood, J D

    2013-01-01

    The Stokes drag and couple acting on a disc moving through incompressible Newtonian fluid are investigated for the case when the fluid obeys a Navier slip condition, with slip length b, on the surface of the disc. The fluid is bounded by an infinite plane wall on which there is no slip. The disc, of zero thickness and radius a, is parallel to the wall and distance h from it. Analyses are presented for the limits h ≫ a and h ≪ a; results for intermediate values of the separation h are obtained numerically by means of Tranter's method. The resistance coefficients for translation normal to the disc surface, and for rotation about a diameter, are unaffected by slip when the disc lies in unbounded fluid, but all resistance coefficients depend upon the slip length b when the disc is close to the wall. Their dependence on h becomes weak when b ≫ a. (paper)

  15. Hall and ion slip effects on peristaltic flow of Jeffrey nanofluid with Joule heating

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, T. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); NAAM Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Shafique, Maryam [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Tanveer, A., E-mail: anum@math.qau.edu.pk [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Alsaedi, A. [NAAM Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2016-06-01

    This paper addresses mixed convective peristaltic flow of Jeffrey nanofluid in a channel with complaint walls. The present investigation includes the viscous dissipation, thermal radiation and Joule heating. Hall and ion slip effects are also taken into account. Related problems through long wavelength and low Reynolds number are examined for stream function, temperature and concentration. Impacts of thermal radiation, Hartman number, Brownian motion parameter, thermophoresis, Joule heating, Hall and ion slip parameters are investigated in detail. It is observed that velocity increases and temperature decreases with Hall and ion slip parameters. Further the thermal radiation on temperature has qualitatively similar role to that of Hall and ion slip effects. - Highlights: • Peristalsis in the presence of Jeffery nanofluid is formulated. • Compliant properties of channel walls are addressed. • Impact of Hall and ion slip effects is outlined. • Influence of Joule heating and radiation is investigated. • Mixed convection for both heat and mass transfer is present.

  16. Is Slow Slip a Cause or a Result of Tremor?

    Science.gov (United States)

    Luo, Y.; Ampuero, J. P.

    2017-12-01

    While various modeling efforts have been conducted to reproduce subsets of observations of tremor and slow-slip events (SSE), a fundamental but yet unanswered question is whether slow slip is a cause or a result of tremor. Tremor is commonly regarded as driven by SSE. This view is mainly based on observations of SSE without detected tremors and on (frequency-limited) estimates of total tremor seismic moment being lower than 1% of their concomitant SSE moment. In previous studies we showed that models of heterogeneous faults, composed of seismic asperities embedded in an aseismic fault zone matrix, reproduce quantitatively the hierarchical patterns of tremor migration observed in Cascadia and Shikoku. To address the title question, we design two end-member models of a heterogeneous fault. In the SSE-driven-tremor model, slow slip events are spontaneously generated by the matrix (even in the absence of seismic asperities) and drive tremor. In the Tremor-driven-SSE model the matrix is stable (it slips steadily in the absence of asperities) and slow slip events result from the collective behavior of tremor asperities interacting via transient creep (local afterslip fronts). We study these two end-member models through 2D quasi-dynamic multi-cycle simulations of faults governed by rate-and-state friction with heterogeneous frictional properties and effective normal stress, using the earthquake simulation software QDYN (https://zenodo.org/record/322459). We find that both models reproduce first-order observations of SSE and tremor and have very low seismic to aseismic moment ratio. However, the Tremor-driven-SSE model assumes a simpler rheology than the SSE-driven-tremor model and matches key observations better and without fine tuning, including the ratio of propagation speeds of forward SSE and rapid tremor reversals and the decay of inter-event times of Low Frequency Earthquakes. These modeling results indicate that, in contrast to a common view, SSE could be a result

  17. Tactile detection of slip: surface microgeometry and peripheral neural codes.

    Science.gov (United States)

    Srinivasan, M A; Whitehouse, J M; LaMotte, R H

    1990-06-01

    1. The role of the microgeometry of planar surfaces in the detection of sliding of the surfaces on human and monkey fingerpads was investigated. By the use of a servo-controlled tactile stimulator to press and stroke glass plates on passive fingerpads of human subjects, the ability of humans to discriminate the direction of skin stretch caused by friction and to detect the sliding motion (slip) of the plates with or without micrometer-sized surface features was determined. To identify the associated peripheral neural codes, evoked responses to the same stimuli were recorded from single, low-threshold mechanoreceptive afferent fibers innervating the fingerpads of anesthetized macaque monkeys. 2. Humans could not detect the slip of a smooth glass plate on the fingerpad. However, the direction of skin stretch was perceived based on the information conveyed by the slowly adapting afferents that respond differentially to the stretch directions. Whereas the direction of skin stretch signaled the direction of impending slip, the perception of relative motion between the plate and the finger required the existence of detectable surface features. 3. Barely detectable micrometer-sized protrusions on smooth surfaces led to the detection of slip of these surfaces, because of the exclusive activation of rapidly adapting fibers of either the Meissner (RA) or the Pacinian (PC) type to specific geometries of the microfeatures. The motion of a smooth plate with a very small single raised dot (4 microns high, 550 microns diam) caused the sequential activation of neighboring RAs along the dot path, thus providing a reliable spatiotemporal code. The stroking of the plate with a fine homogeneous texture composed of a matrix of dots (1 microns high, 50 microns diam, and spaced at 100 microns center-to-center) induced vibrations in the fingerpad that activated only the PCs and resulted in an intensive code. 4. The results show that surprisingly small features on smooth surfaces are

  18. Capital gains

    International Nuclear Information System (INIS)

    Blishen, C.

    1997-01-01

    This article examines African and Middle East oil and natural gas project financing. Capital markets financing, Ras Laffan's project bonds, capital market issues in Saudi Arabia, the movement toward gas and away from oil, and Islamic opportunities are discussed, African and Middle East oil and gas projects are listed. (UK)

  19. Influence of slip-surface geometry on earth-flow deformation, Montaguto earth flow, southern Italy

    Science.gov (United States)

    Guerriero, L.; Coe, Jeffrey A.; Revellio, P.; Grelle, G.; Pinto, F.; Guadagno, F.

    2016-01-01

    We investigated relations between slip-surface geometry and deformational structures and hydrologic features at the Montaguto earth flow in southern Italy between 1954 and 2010. We used 25 boreholes, 15 static cone-penetration tests, and 22 shallow-seismic profiles to define the geometry of basal- and lateral-slip surfaces; and 9 multitemporal maps to quantify the spatial and temporal distribution of normal faults, thrust faults, back-tilted surfaces, strike-slip faults, flank ridges, folds, ponds, and springs. We infer that the slip surface is a repeating series of steeply sloping surfaces (risers) and gently sloping surfaces (treads). Stretching of earth-flow material created normal faults at risers, and shortening of earth-flow material created thrust faults, back-tilted surfaces, and ponds at treads. Individual pairs of risers and treads formed quasi-discrete kinematic zones within the earth flow that operated in unison to transmit pulses of sediment along the length of the flow. The locations of strike-slip faults, flank ridges, and folds were not controlled by basal-slip surface topography but were instead dependent on earth-flow volume and lateral changes in the direction of the earth-flow travel path. The earth-flow travel path was strongly influenced by inactive earth-flow deposits and pre-earth-flow drainages whose positions were determined by tectonic structures. The implications of our results that may be applicable to other earth flows are that structures with strikes normal to the direction of earth-flow motion (e.g., normal faults and thrust faults) can be used as a guide to the geometry of basal-slip surfaces, but that depths to the slip surface (i.e., the thickness of an earth flow) will vary as sediment pulses are transmitted through a flow.

  20. EBSD analysis of subgrain boundaries and dislocation slip systems in Antarctic and Greenland ice

    Directory of Open Access Journals (Sweden)

    I. Weikusat

    2017-09-01

    Full Text Available Ice has a very high plastic anisotropy with easy dislocation glide on basal planes, while glide on non-basal planes is much harder. Basal glide involves dislocations with the Burgers vector b = 〈a〉, while glide on non-basal planes can involve dislocations with b = 〈a〉, b = [c], and b = 〈c + a〉. During the natural ductile flow of polar ice sheets, most of the deformation is expected to occur by basal slip accommodated by other processes, including non-basal slip and grain boundary processes. However, the importance of different accommodating processes is controversial. The recent application of micro-diffraction analysis methods to ice, such as X-ray Laue diffraction and electron backscattered diffraction (EBSD, has demonstrated that subgrain boundaries indicative of non-basal slip are present in naturally deformed ice, although so far the available data sets are limited. In this study we present an analysis of a large number of subgrain boundaries in ice core samples from one depth level from two deep ice cores from Antarctica (EPICA-DML deep ice core at 656 m of depth and Greenland (NEEM deep ice core at 719 m of depth. EBSD provides information for the characterization of subgrain boundary types and on the dislocations that are likely to be present along the boundary. EBSD analyses, in combination with light microscopy measurements, are presented and interpreted in terms of the dislocation slip systems. The most common subgrain boundaries are indicative of basal 〈a〉 slip with an almost equal occurrence of subgrain boundaries indicative of prism [c] or 〈c + a〉 slip on prism and/or pyramidal planes. A few subgrain boundaries are indicative of prism 〈a〉 slip or slip of 〈a〉 screw dislocations on the basal plane. In addition to these classical polygonization processes that involve the recovery of dislocations into boundaries, alternative mechanisms are discussed for the formation of subgrain

  1. Sand in the Wheels of Capitalism

    DEFF Research Database (Denmark)

    Bersem, Mario; Perotti, Enrico; von Thadden, Ernst-Ludwig

    We present a positive theory of capital market frictions that raise the cost of capital for new firms and lower the cost of capital for incumbent firms. Capital market frictions arise from a political conflict across voters who differ in two dimensions: (i) a fraction of voters owns capital......, the rest receives only lab or income; and (ii) voters have different vintages of human capital. We identify young workers as the decisive voter group, with preferences in between capitalists who favor a free capital market, and old workers, who favor restricted capital mobility. We show that capital market...... frictions do not naturally arise in a static framework, or even in a dynamic framework if capital market frictions are reversible. But if capital market frictions can be made to p ersist over time, we show that young workers favor capital market frictions as a way to smo oth income, especially if wealth...

  2. Capital Flight from Russia

    OpenAIRE

    Prakash Loungani; Paolo Mauro

    2000-01-01

    This paper documents the scale of capital flight from Russia, compares it with that observed in other countries, and reviews policy options. The evidence from other countries suggests that capital flight can be reversed once reforms take hold. The paper argues that capital flight from Russia can only be curbed through a medium-term reform strategy aimed at improving governance and macroeconomic performance, and strengthening the banking system. Capital controls result in costly distortions an...

  3. Onset of aseismic creep on major strike-slip faults

    KAUST Repository

    Çakir, Ziyadin

    2012-10-02

    Time series analysis of spaceborne synthetic aperture radar (SAR) data, GPS measurements, and fi eld observations reveal that the central section of the Izmit (Turkey) fault that slipped with a supershear rupture velocity in the A.D. 1999, Mw7.4, Izmit earthquake began creeping aseismically following the earthquake. Rapid initial postseismic afterslip decayed logarithmically with time and appears to have reached a steady rate comparable to the preearthquake full fault-crossing rate, suggesting that it may continue for decades and possibly until late in the earthquake cycle. If confi rmed by future monitoring, these observations identify postseismic afterslip as a mechanism for initiating creep behavior along strike-slip faults. Long-term afterslip and/or creep has signifi cant implications for earthquake cycle models, recurrence intervals of large earthquakes, and accordingly, seismic hazard estimation along mature strike-slip faults, in particular for Istanbul which is believed to lie adjacent to a seismic gap along the North Anatolian fault in the Sea of Marmara. © 2012 Geological Society of America.

  4. Onset of aseismic creep on major strike-slip faults

    KAUST Repository

    Ç akir, Ziyadin; Ergintav, Semih; Ö zener, Haluk; Doǧan, Uǧur; Akoglu, Ahmet; Meghraoui, Mustapha; Reilinger, Robert E.

    2012-01-01

    Time series analysis of spaceborne synthetic aperture radar (SAR) data, GPS measurements, and fi eld observations reveal that the central section of the Izmit (Turkey) fault that slipped with a supershear rupture velocity in the A.D. 1999, Mw7.4, Izmit earthquake began creeping aseismically following the earthquake. Rapid initial postseismic afterslip decayed logarithmically with time and appears to have reached a steady rate comparable to the preearthquake full fault-crossing rate, suggesting that it may continue for decades and possibly until late in the earthquake cycle. If confi rmed by future monitoring, these observations identify postseismic afterslip as a mechanism for initiating creep behavior along strike-slip faults. Long-term afterslip and/or creep has signifi cant implications for earthquake cycle models, recurrence intervals of large earthquakes, and accordingly, seismic hazard estimation along mature strike-slip faults, in particular for Istanbul which is believed to lie adjacent to a seismic gap along the North Anatolian fault in the Sea of Marmara. © 2012 Geological Society of America.

  5. Impact from the blockchain technology on the Nordic capital market

    OpenAIRE

    Victoria, Karlsson Lundström

    2016-01-01

    This master thesis explores how the blockchain technology might affect the capital market, a market with an established role in our current society. This exploration is conducted by a literature study and an interview study with participants within the capital market, in order to gather several opinions and experiences of the technology. The blockchain technology is a registration technology that provides a high degree of security and the possibility to cut of intermediaries. These are two su...

  6. Slow slip events in Guerrero, Mexico, and consequences on strain accumulation over the past 15 years.

    Science.gov (United States)

    Radiguet, M.; Cotton, F.; Cavalié, O.; Pathier, E.; Kostoglodov, V.; Vergnolle, M.; Campillo, M.; Walpersdorf, A.; Cotte, N.; Santiago, J.; Franco, S.

    2012-12-01

    Continuous Global Positioning System (cGPS) time series in Guerrero, Mexico, reveal the widespread existence of large Slow Slip Events (SSEs) at the boundary between the Cocos and North American plates. The existence of these SSEs asks the question of how seismic and aseismic slips complement each other in subduction zones. We examined the last three SSEs that occurred in 2001/2002, 2006 and 2009/2010, and their impact on the strain accumulation along the Guerrero subduction margin. We use continuous cGPS time series and InSAR images to evaluate the surface displacement during SSEs and inter-SSE periods. The slip distributions on the plate interface associated with each SSE, as well as the inter-SSE (short-term) coupling rates are evaluated by inverting these surface displacements. Our results reveal that the three analyzed SSEs have equivalent moment magnitudes of around 7.5 and their lateral extension is variable.The slip distributions for the three SSEs show that in the Guerrero gap area, the slow slip occurs at shallower depth (updip limit around 15-20 km) than in surrounding regions. The InSAR data provide additional information for the 2006 SSE. The joint inversion of InSAR and cGPS data confirms the lateral variation of the slip distribution along the trench, with shallower slip in the Guerrero seismic gap, west of Acapulco, and deeper slip further east. Inversion of inter-SSE displacement rates reveal that during the inter-SSE time intervals, the interplate coupling is high in the area where the slow slip subsequently occurs. Over a 12 year period, corresponding to three cycles of SSEs, our results reveal that the accumulated slip deficit in the Guerrero gap area is only ¼ of the slip deficit accumulated on both sides of the gap. Moreover, the regions of large slip deficit coincide with the rupture areas of recent large earthquakes. We conclude that the SSEs account for a major portion of the overall moment release budget in the Guerrero gap. If large

  7. Numerical Simulation of Methane Slip in Dual Fuel Marine Engines

    DEFF Research Database (Denmark)

    Han, Jaehyun; Jensen, Michael Vincent; Pang, Kar Mun

    2017-01-01

    estimations. The simulations with various gas pipe geometries were conducted. It seemed that the effect of the change in injection direction is more dominant than the change in the gas hole configuration. The favorable injection direction for minimum amount of methane slip was discovered as the direction...... which helps developing the flow of methane far from the exhaust ports. The effects of various valve timing settings were also simulated. The advancement of the exhaust valve closing was more efficient than the retardation of the intake valve opening. A little retardation of the intake valve opening even......The methane slip is the problematic issue for the engines using natural gas(NG). Because methane is more powerful greenhouse gas (GHG) than CO2, understanding of the methane slip during gas exchange process of the engines is essential. In this study, the influence of the gas pipe geometry...

  8. Dislocation pile-ups, slip-bands, ellipsoids, and cracks

    International Nuclear Information System (INIS)

    Brown, Lawrence M.

    2005-01-01

    The classic theories of dislocation pile-ups, initiated by Eshelby, Frank and Nabarro, and by Leibfried, can be greatly simplified if it is recognised that the dislocations in the pile-up will experience uniform stress if they are lodged in an ellipsoidal interface. Elementary algebra then produces the familiar results from continuum theory. It seems possible that the ellipsoid construction may represent physical reality if it is taken to represent a three-dimensional slip-band. If so, there are concentrated forces spreading the band perpendicular to the slip band as well as parallel to it. Such ellipsoids also represent Mode II and Mode III cracks, and give a method for dealing with the more complicated Mode I cracks

  9. Studying friction while playing the violin: exploring the stick-slip phenomenon.

    Science.gov (United States)

    Casado, Santiago

    2017-01-01

    Controlling the stick-slip friction phenomenon is of major importance for many familiar situations. This effect originates from the periodic rupture of junctions created between two rubbing surfaces due to the increasing shear stress at the interface. It is ultimately responsible for the behavior of many braking systems, earthquakes, and unpleasant squeaky sounds caused by the scratching of two surfaces. In the case of a musical bow-stringed instrument, stick-slip is controlled in order to provide well-tuned notes at different intensities. A trained ear is able to distinguish slight sound variations caused by small friction differences. Hence, a violin can be regarded as a perfect benchmark to explore the stick-slip effect at the mesoscale. Two violin bow hairs were studied, a natural horse tail used in a professional philharmonic orchestra, and a synthetic one used with a violin for beginners. Atomic force microscopy characterization revealed clear differences when comparing the surfaces of both bow hairs, suggesting that a structure having peaks and a roughness similar to that of the string to which both bow hairs rubbed permits a better control of the stick-slip phenomenon.

  10. Optimal fall indicators for slip induced falls on a cross-slope.

    Science.gov (United States)

    Domone, Sarah; Lawrence, Daniel; Heller, Ben; Hendra, Tim; Mawson, Sue; Wheat, Jonathan

    2016-08-01

    Slip-induced falls are among the most common cause of major occupational injuries in the UK as well as being a major public health concern in the elderly population. This study aimed to determine the optimal fall indicators for fall detection models which could be used to reduce the detrimental consequences of falls. A total of 264 kinematic variables covering three-dimensional full body model translation and rotational measures were analysed during normal walking, successful recovery from slips and falls on a cross-slope. Large effect sizes were found for three kinematic variables which were able to distinguish falls from normal walking and successful recovery. Further work should consider other types of daily living activities as results show that the optimal kinematic fall indicators can vary considerably between movement types. Practitioner Summary: Fall detection models are used to minimise the adverse consequences of slip-induced falls, a major public health concern. Optimal fall indicators were derived from a comprehensive set of kinematic variables for slips on a cross-slope. Results suggest robust detection of falls is possible on a cross-slope but may be more difficult than level walking.

  11. Discrete Boltzmann Method with Maxwell-Type Boundary Condition for Slip Flow

    Science.gov (United States)

    Zhang, Yu-Dong; Xu, Ai-Guo; Zhang, Guang-Cai; Chen, Zhi-Hua

    2018-01-01

    The rarefied effect of gas flow in microchannel is significant and cannot be well described by traditional hydrodynamic models. It has been known that discrete Boltzmann model (DBM) has the potential to investigate flows in a relatively wider range of Knudsen number because of its intrinsic kinetic nature inherited from Boltzmann equation. It is crucial to have a proper kinetic boundary condition for DBM to capture the velocity slip and the flow characteristics in the Knudsen layer. In this paper, we present a DBM combined with Maxwell-type boundary condition model for slip flow. The tangential momentum accommodation coefficient is introduced to implement a gas-surface interaction model. Both the velocity slip and the Knudsen layer under various Knudsen numbers and accommodation coefficients can be well described. Two kinds of slip flows, including Couette flow and Poiseuille flow, are simulated to verify the model. To dynamically compare results from different models, the relation between the definition of Knudsen number in hard sphere model and that in BGK model is clarified. Support of National Natural Science Foundation of China under Grant Nos. 11475028, 11772064, and 11502117 Science Challenge Project under Grant Nos. JCKY2016212A501 and TZ2016002

  12. Studying friction while playing the violin: exploring the stick–slip phenomenon

    Directory of Open Access Journals (Sweden)

    Santiago Casado

    2017-01-01

    Full Text Available Controlling the stick–slip friction phenomenon is of major importance for many familiar situations. This effect originates from the periodic rupture of junctions created between two rubbing surfaces due to the increasing shear stress at the interface. It is ultimately responsible for the behavior of many braking systems, earthquakes, and unpleasant squeaky sounds caused by the scratching of two surfaces. In the case of a musical bow-stringed instrument, stick–slip is controlled in order to provide well-tuned notes at different intensities. A trained ear is able to distinguish slight sound variations caused by small friction differences. Hence, a violin can be regarded as a perfect benchmark to explore the stick–slip effect at the mesoscale. Two violin bow hairs were studied, a natural horse tail used in a professional philharmonic orchestra, and a synthetic one used with a violin for beginners. Atomic force microscopy characterization revealed clear differences when comparing the surfaces of both bow hairs, suggesting that a structure having peaks and a roughness similar to that of the string to which both bow hairs rubbed permits a better control of the stick–slip phenomenon.

  13. Selection of intellectual capital management strategies

    OpenAIRE

    Shcherbachenko Viktoriia Oleksiivna

    2016-01-01

    This article deals with the selection of intellectual capital management strategy. The attention is paid to the structure of intellectual capital, which consists of human capital, customer capital, process capital, intellectual property, intangible assets. The algorithm of selection of intellectual capital management strategy was created by author.

  14. Understanding Capitalism

    DEFF Research Database (Denmark)

    du Gay, Paul; Morgan, Glenn

    2013-01-01

    This chapter places The New Spirit of Capitalism in the context of the development of capitalism over the last twenty years, up to and including the 200-7-8 financial crisis and the ongoing economic crisis which has developed out of this and is now focused on the relationship between state expend...

  15. Slip resistance of winter footwear on snow and ice measured using maximum achievable incline.

    Science.gov (United States)

    Hsu, Jennifer; Shaw, Robert; Novak, Alison; Li, Yue; Ormerod, Marcus; Newton, Rita; Dutta, Tilak; Fernie, Geoff

    2016-05-01

    Protective footwear is necessary for preventing injurious slips and falls in winter conditions. Valid methods for assessing footwear slip resistance on winter surfaces are needed in order to evaluate footwear and outsole designs. The purpose of this study was to utilise a method of testing winter footwear that was ecologically valid in terms of involving actual human testers walking on realistic winter surfaces to produce objective measures of slip resistance. During the experiment, eight participants tested six styles of footwear on wet ice, on dry ice, and on dry ice after walking over soft snow. Slip resistance was measured by determining the maximum incline angles participants were able to walk up and down in each footwear-surface combination. The results indicated that testing on a variety of surfaces is necessary for establishing winter footwear performance and that standard mechanical bench tests for footwear slip resistance do not adequately reflect actual performance. Practitioner Summary: Existing standardised methods for measuring footwear slip resistance lack validation on winter surfaces. By determining the maximum inclines participants could walk up and down slopes of wet ice, dry ice, and ice with snow, in a range of footwear, an ecologically valid test for measuring winter footwear performance was established.

  16. Grain scale observations of stick-slip dynamics in fluid saturated granular fault gouge

    Science.gov (United States)

    Johnson, P. A.; Dorostkar, O.; Guyer, R. A.; Marone, C.; Carmeliet, J.

    2017-12-01

    We are studying granular mechanics during slip. In the present work, we conduct coupled computational fluid dynamics (CFD) and discrete element method (DEM) simulations to study grain scale characteristics of slip instabilities in fluid saturated granular fault gouge. The granular sample is confined with constant normal load (10 MPa), and sheared with constant velocity (0.6 mm/s). This loading configuration is chosen to promote stick-slip dynamics, based on a phase-space study. Fluid is introduced in the beginning of stick phase and characteristics of slip events i.e. macroscopic friction coefficient, kinetic energy and layer thickness are monitored. At the grain scale, we monitor particle coordination number, fluid-particle interaction forces as well as particle and fluid kinetic energy. Our observations show that presence of fluids in a drained granular fault gouge stabilizes the layer in the stick phase and increases the recurrence time. In saturated model, we observe that average particle coordination number reaches higher values compared to dry granular gouge. Upon slip, we observe that a larger portion of the granular sample is mobilized in saturated gouge compared to dry system. We also observe that regions with high particle kinetic energy are correlated with zones of high fluid motion. Our observations highlight that spatiotemporal profile of fluid dynamic pressure affects the characteristics of slip instabilities, increasing macroscopic friction coefficient drop, kinetic energy release and granular layer compaction. We show that numerical simulations help characterize the micromechanics of fault mechanics.

  17. Dynamics of fault slip near the stability transition combining laboratory and numerical experiments

    Science.gov (United States)

    Mele Veedu, D.; Giorgetti, C.; Scuderi, M. M.; Barbot, S.; Marone, C.; Collettini, C.

    2017-12-01

    Frictional stability controls the seismogenic potential of faults. Laboratory (1) and theoretical (2) studies document and predict the conditions under which fault slip is seismic or aseismic. However, the full gamut of fault slip behavior near the stable/unstable boundary is still poorly known. Here, we combine insight from laboratory and numerical experiments to identify the wide spectrum of frictional instabilities around that transition, including slow-slip events, period-multiplying events, and chaos. We present a synoptic picture of the dynamics of fault slip in a bifurcation diagram obtained from a series of laboratory and numerical experiments. We compare the laboratory observations with spring-slider and finite-fault numerical models. In the laboratory, we vary the stiffness of the system by modulating the stress field around the experimental fault. In the numerical experiments, we vary the characteristic weakening distance to explore a range of critical nucleation sizes. Contrarily to previously found (3), complex fault dynamics can be obtained with a rate-and-state constitutive law with a single state variable. While the dynamics of fault slip is complicated on large faults by the presence of morphological and rheological heterogeneities, the range of instabilities identified in the laboratory is reminiscent of the variety of slow and fast earthquakes found along subduction zones (4). The accord between laboratory data and theoretical models affords more realistic predictions of fault behavior at slow slip speeds. (1) Scuderi et al., (2016), (2) Ruina (1983), (3) Gu & Wong (1994), (4) Obara & Kato (2016)

  18. A Multiple Data Fusion Approach to Wheel Slip Control for Decentralized Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Dejun Yin

    2017-04-01

    Full Text Available Currently, active safety control methods for cars, i.e., the antilock braking system (ABS, the traction control system (TCS, and electronic stability control (ESC, govern the wheel slip control based on the wheel slip ratio, which relies on the information from non-driven wheels. However, these methods are not applicable in the cases without non-driven wheels, e.g., a four-wheel decentralized electric vehicle. Therefore, this paper proposes a new wheel slip control approach based on a novel data fusion method to ensure good traction performance in any driving condition. Firstly, with the proposed data fusion algorithm, the acceleration estimator makes use of the data measured by the sensor installed near the vehicle center of mass (CM to calculate the reference acceleration of each wheel center. Then, the wheel slip is constrained by controlling the acceleration deviation between the actual wheel and the reference wheel center. By comparison with non-control and model following control (MFC cases in double lane change tests, the simulation results demonstrate that the proposed control method has significant anti-slip effectiveness and stabilizing control performance.

  19. Fires in the Australian Capital Territory

    Science.gov (United States)

    2003-01-01

    The height and extent of billowing smoke plumes from bushfires near Canberra, the Australian capital, are illustrated by these views from the Multi-angle Imaging SpectroRadiometer (MISR). The images were acquired on January 18, 2003. Never before had fires of this magnitude come so close to Australia's capital. Four people lost their lives and over 500 homes were destroyed, mostly in the southwestern suburbs. Australia's famous Mount Stromlo Observatory, located immediately west of the city, was also incinerated by the fires.The top panel portrays a natural-color view from MISR's nadir camera, in which the eastern portion of the Australian Capital Territory is located south of a pale, ephemeral lake in the upper left-hand corner (Lake George). Several smoke plumes originate within the eastern part of the Australian Capital Territory, while the major plumes originate to the west of the image area. The Australian Capital Territory and much of New South Wales are completely obscured by the smoke, which is driven by fierce westerly winds and extends eastward to the coast and over the Pacific Ocean.The lower panel provides a stereoscopically retrieved height field of the clouds and smoke plumes. The greenish areas indicate where smoke plumes extend several kilometers above a bank of patchy stratus clouds below. A few high clouds appear near the bottom of the image. Wind retrievals were excluded from this image in order to generate a smooth and continuous field. Although relative height variations are well-represented here, the inclusion of wind retrievals for this scene reduces the actual cloud height results by 1 to 2 kilometers. Areas where heights could not be retrieved are shown as dark gray.The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuouslyand every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. This data product was generated from a portion of the imagery acquired during Terra orbit 16421. The

  20. THE IMPORTANCE OF STATE’S ROLE IN THE HUNGARIAN VENTURE CAPITAL MARKET

    Directory of Open Access Journals (Sweden)

    Jenő Konecsny

    2011-07-01

    Full Text Available The presence of state also has an indirect and direct effect on the developement of the Hungarian venture capital market. Indirect effect is realized through the law legislation and the direct one by the operate of the different venture capital firms and funds which invest public financial sources. The main purpose of the direct intervention is to finance the under-capitalized small and medium-sized start-up companies with equity. The paper examines the Hungarian venture capital market from the aspect of state intervention. It starts with an European overview which summarizes the common and different attributes of state’s role in the venture capital market between several European countries. The paper focuses on the Hungarian situation, it describes concisely the effect and efficiency of the governmental instructions which were taken for the legislation of the venture capital market. Using the results of a previous research the paper also examines the characteristics of the direct instructions. The paper decribes briefly the main details of the publicprivate initiative called JEREMIE-program, which started on the Hungarian venture capital market in the recent past.

  1. Analysing earthquake slip models with the spatial prediction comparison test

    KAUST Repository

    Zhang, L.; Mai, Paul Martin; Thingbaijam, Kiran Kumar; Razafindrakoto, H. N. T.; Genton, Marc G.

    2014-01-01

    Earthquake rupture models inferred from inversions of geophysical and/or geodetic data exhibit remarkable variability due to uncertainties in modelling assumptions, the use of different inversion algorithms, or variations in data selection and data processing. A robust statistical comparison of different rupture models obtained for a single earthquake is needed to quantify the intra-event variability, both for benchmark exercises and for real earthquakes. The same approach may be useful to characterize (dis-)similarities in events that are typically grouped into a common class of events (e.g. moderate-size crustal strike-slip earthquakes or tsunamigenic large subduction earthquakes). For this purpose, we examine the performance of the spatial prediction comparison test (SPCT), a statistical test developed to compare spatial (random) fields by means of a chosen loss function that describes an error relation between a 2-D field (‘model’) and a reference model. We implement and calibrate the SPCT approach for a suite of synthetic 2-D slip distributions, generated as spatial random fields with various characteristics, and then apply the method to results of a benchmark inversion exercise with known solution. We find the SPCT to be sensitive to different spatial correlations lengths, and different heterogeneity levels of the slip distributions. The SPCT approach proves to be a simple and effective tool for ranking the slip models with respect to a reference model.

  2. Analysing earthquake slip models with the spatial prediction comparison test

    KAUST Repository

    Zhang, L.

    2014-11-10

    Earthquake rupture models inferred from inversions of geophysical and/or geodetic data exhibit remarkable variability due to uncertainties in modelling assumptions, the use of different inversion algorithms, or variations in data selection and data processing. A robust statistical comparison of different rupture models obtained for a single earthquake is needed to quantify the intra-event variability, both for benchmark exercises and for real earthquakes. The same approach may be useful to characterize (dis-)similarities in events that are typically grouped into a common class of events (e.g. moderate-size crustal strike-slip earthquakes or tsunamigenic large subduction earthquakes). For this purpose, we examine the performance of the spatial prediction comparison test (SPCT), a statistical test developed to compare spatial (random) fields by means of a chosen loss function that describes an error relation between a 2-D field (‘model’) and a reference model. We implement and calibrate the SPCT approach for a suite of synthetic 2-D slip distributions, generated as spatial random fields with various characteristics, and then apply the method to results of a benchmark inversion exercise with known solution. We find the SPCT to be sensitive to different spatial correlations lengths, and different heterogeneity levels of the slip distributions. The SPCT approach proves to be a simple and effective tool for ranking the slip models with respect to a reference model.

  3. Hydro-Mechanical Modelling of Slow Slip Phenomena at the Subduction Interface.

    Science.gov (United States)

    Petrini, C.; Gerya, T.; Madonna, C.; van Dinther, Y.

    2016-12-01

    Subduction zones experience a spectrum of slip phenomena, ranging from large devastating megathrust earthquakes to aseismic slow slip events. Slow slip events, lasting hours to years and being perceptible only by instruments, are believed to have the capability to induce large earthquakes. It is also repeatedly proposed that such slow events are controlled by fluid-rock interactions along the subduction interface, thus calling for development of fully coupled seismo-hydro-mechanical modeling approaches to identify their physics and controlling parameters. We present a newly developed finite difference visco-elasto-plastic numerical code with marker-in-cell technique, which fully couples mechanical deformation and fluid flow. We use this to investigate how the presence of fluids in the pore space of a (de)compacting rock matrix affects elastic stress accumulation and release along a fluid-bearing subduction interface. The model simulates the spontaneous occurrence of quasi-periodic slow slip phenomena along self-consistently forming highly localized shearbands, which accommodate shear displacement between two plates. The produced elastic rebound events show a slip velocity on the order of cm/yr, which is in good agreement with measured data. The governing gradual strength decrease along the slowly propagating shear bands is related to a drop in total pressure caused by shear localization at nearly constant (slightly decreasing) fluid pressure. Gradual reduction of the difference between the total and fluid pressure decreases brittle/plastic strength of fluid-bearing rocks along the shear bands, thus providing a dynamic feedback mechanism for the accumulated elastic stress release at the subduction interface.

  4. Triggered surface slips in the Coachella Valley area associated with the 1992 Joshua Tree and Landers, California, Earthquakes

    Science.gov (United States)

    Rymer, M.J.

    2000-01-01

    The Coachella Valley area was strongly shaken by the 1992 Joshua Tree (23 April) and Landers (28 June) earthquakes, and both events caused triggered slip on active faults within the area. Triggered slip associated with the Joshua Tree earthquake was on a newly recognized fault, the East Wide Canyon fault, near the southwestern edge of the Little San Bernardino Mountains. Slip associated with the Landers earthquake formed along the San Andreas fault in the southeastern Coachella Valley. Surface fractures formed along the East Wide Canyon fault in association with the Joshua Tree earthquake. The fractures extended discontinuously over a 1.5-km stretch of the fault, near its southern end. Sense of slip was consistently right-oblique, west side down, similar to the long-term style of faulting. Measured offset values were small, with right-lateral and vertical components of slip ranging from 1 to 6 mm and 1 to 4 mm, respectively. This is the first documented historic slip on the East Wide Canyon fault, which was first mapped only months before the Joshua Tree earthquake. Surface slip associated with the Joshua Tree earthquake most likely developed as triggered slip given its 5 km distance from the Joshua Tree epicenter and aftershocks. As revealed in a trench investigation, slip formed in an area with only a thin (Salton Trough. A paleoseismic trench study in an area of 1992 surface slip revealed evidence of two and possibly three surface faulting events on the East Wide Canyon fault during the late Quaternary, probably latest Pleistocene (first event) and mid- to late Holocene (second two events). About two months after the Joshua Tree earthquake, the Landers earthquake then triggered slip on many faults, including the San Andreas fault in the southeastern Coachella Valley. Surface fractures associated with this event formed discontinuous breaks over a 54-km-long stretch of the fault, from the Indio Hills southeastward to Durmid Hill. Sense of slip was right

  5. Phase slip process and charge density wave dynamics in a one dimensional conductor

    Science.gov (United States)

    Habiballah, N.; Zouadi, M.; Arbaoui, A.; Qjani, M.; Dumas, J.

    In this paper, we study the phase slip effect on the charge density wave (CDW) dynamics in a one-dimensional conductor in the weak pinning limit. A considerable enhancement of JCDW is observed in the presence of phase slips. In addition, a spatial dependence of the CDW current density JCDW is also studied showing that a decrease of JCDW with distance from the current contact occurs. The results are discussed in terms the relationship between additional phase slips and the mobility of phase dislocations nucleated at electrical contacts.

  6. Selection of intellectual capital management strategies

    Directory of Open Access Journals (Sweden)

    Shcherbachenko Viktoriia Oleksiivna

    2016-02-01

    Full Text Available This article deals with the selection of intellectual capital management strategy. The attention is paid to the structure of intellectual capital, which consists of human capital, customer capital, process capital, intellectual property, intangible assets. The algorithm of selection of intellectual capital management strategy was created by author.

  7. Insights into the causal relationship between slow slip and tectonic tremor in Guerrero, Mexico

    Science.gov (United States)

    Villafuerte, Carlos; Cruz-Atienza, Víctor M.

    2017-08-01

    Similar to other subduction zones, tectonic tremors (TTs) and slow-slip events (SSEs) take place in the deep segment of the plate interface in Guerrero, Mexico. However, their spatial correlation in this region is not as clear as the episodic tremor and slip observed in Cascadia and Japan. In this study we provide insights into the causal relationship between TTs and SSEs in Guerrero by analyzing the evolution of the deformation fields induced by the long-term 2006 SSE together with new locations of TTs and low-frequency earthquakes (LFEs). Unlike previous studies we find that the SSE slip rate modulates the TT and LFE activity in the whole tremor region. This means that the causal relationship between the SSE and the TT activity directly depends on the stressing rate history of the tremor asperities that is modulated by the surrounding slip rate. We estimated that the frictional strength of the asperities producing tremor downdip in the sweet spot is around 3.2 kPa, which is 2.3 times smaller than the corresponding value updip in the transient zone, partly explaining the overwhelming tremor activity of the sweet spot despite that the slow slip there is smaller. Based on the LFE occurrence-rate history during the interlong-term SSE period, we determined that the short-term SSEs in Guerrero take place further downdip (about 35 km) than previously estimated, with maximum slip of about 8 mm in the sweet spot. This new model features a continuum of slow slip extending across the entire tremor region of Guerrero.

  8. Introduction to special section on phenomenology, underlying processes, and hazard implications of aseismic slip and nonvolcanic tremor

    Science.gov (United States)

    Gomberg, Joan

    2010-01-01

    This paper introduces the special section on the "phenomenology, underlying processes, and hazard implications of aseismic slip and nonvolcanic tremor" by highlighting key results of the studies published in it. Many of the results indicate that seismic and aseismic manifestations of slow slip reflect transient shear displacements on the plate interface, with the outstanding exception of northern Cascadia where tremor sources have been located on and above the plate interface (differing models of the plate interface there also need to be reconciled). Slow slip phenomena appear to result from propagating deformation that may develop with persistent gaps and segment boundaries. Results add to evidence that when tectonic deformation is relaxed via slow slip, most relaxation occurs aseismically but with seismic signals providing higher-resolution proxies for the aseismic slip. Instead of two distinct slip modes as suggested previously, lines between "fast" and "slow" slip more appropriately may be described as blurry zones. Results reported also show that slow slip sources do not coincide with a specific temperature or metamorphic reaction. Their associations with zones of high conductivity and low shear to compressional wave velocity ratios corroborate source models involving pore fluid pressure buildup and release. These models and spatial anticorrelations between earthquake and tremor activity also corroborate a linkage between slow slip and frictional properties transitional between steady state and stick-slip. Finally, this special section highlights the benefits of global and multidisciplinary studies, which demonstrate that slow phenomena are not confined to beneath the locked zone but exist in many settings.

  9. Private Equity and Regulatory Capital

    NARCIS (Netherlands)

    Bongaerts, D.; Charlier, E.

    2008-01-01

    Regulatory Capital requirements for European banks have been put forward in the Basel II Capital Framework and subsequently in the Capital Requirements Directive (CRD) of the EU. We provide a detailed discussion of the capital requirements for private equity investments under the simple risk weight

  10. Viscous slip coefficients for binary gas mixtures measured from mass flow rates through a single microtube

    OpenAIRE

    Yamaguchi, H.; Takamori, K.; Perrier, P.; Graur, I.; Matsuda, Y.; Niimi, T.

    2016-01-01

    The viscous slip coefficient for helium-argon binary gas mixture is extracted from the experimental values of the mass flow rate through a microtube. The mass flow rate is measured by the constant-volume method. The viscous slip coefficient was obtained by identifying the measured mass flow rate through a microtube with the corresponding analytical expression, which is a function of the Knudsen number. The measurements were carried out in the slip flow regime where the first-order slip bounda...

  11. The effect of human capital, social capital, and perceptual values on nascent entrepreneurs' export intentions

    DEFF Research Database (Denmark)

    Christensen, Poul Rind; Evald, Majbritt Rostgaard; Klyver, Kim

    2011-01-01

    This study investigates the influence of human capital, social capital, and cognition on nascent entrepreneurs' export intentions. The results indicate that while human capital and social capital influence the level of intended export, cognitive characteristics, such as self-efficacy and risk...

  12. Measuring Social Capital Investment: Scale Development and Examination of Links to Social Capital and Perceived Stress

    Science.gov (United States)

    Wegner, Rhiana; Gong, Jie; Fang, Xiaoyi; Kaljee, Linda

    2014-01-01

    Individuals with greater social capital have better health outcomes. Investment in social capital likely increases one’s own social capital, bearing great implications for disease prevention and health promotion. In this study, the authors developed and validated the Social Capital Investment Inventory (SCII). Direct effects of social capital investment on perceived stress, and indirect effects through social capital were examined. 397 Participants from Beijing and Wuhan, China completed surveys. Analyses demonstrated that the SCII has a single factor structure and strong internal consistency. Structural equation modeling showed that individuals who invested more in social capital had greater bonding social capital, and subsequently less perceived stress. Results suggest that disease prevention and health promotion programs should consider approaches to encourage social capital investment; individuals may be able to reduce stress by increasing their investment in social capital. Future research is needed to provide additional empirical support for the SCII and observed structural relationships. PMID:25648725

  13. Higher Bank Capital Requirements and Mortgage Pricing: Evidence from the Countercyclical Capital Buffer (CCB)

    OpenAIRE

    Basten, Christhoph; Koch, Cathérine

    2015-01-01

    How has the CCB affected mortgage pricing after Switzerland became the first country to activate this Basel III macroprudential tool? By analyzing a database with several offers per mortgage request, we construct a picture of mortgage supply and demand. We find, first, that the CCB changes the composition of mortgage supply, as relatively capital-constrained and mortgage-specialized banks raise prices more than their competitors do. Second, risk-weighting schemes linked to borrower risk do no...

  14. Flows of Incompressible Fluids subject to Navier’s slip on the boundary

    Czech Academy of Sciences Publication Activity Database

    Hron, J.; Le Roux, C.; Málek, Josef; Rajagopal, K.R.

    2008-01-01

    Roč. 56, č. 8 (2008), s. 2128-2143 ISSN 0898-1221 R&D Projects: GA ČR GA101/05/2537 Institutional research plan: CEZ:AV0Z20760514 Keywords : boundary conditions * navier’s slip * no-slip Subject RIV: BK - Fluid Dynamics Impact factor: 0.997, year: 2008 http://www.sciencedirect.com

  15. Capital Flight and Economic Performance

    OpenAIRE

    Beja, Edsel Jr.

    2007-01-01

    Capital flight aggravates resource constraints and contributes to undermine long-term economic growth. Counterfactual calculations on the Philippines suggest that capital flight contributed to lower the quality of long-term economic growth. Sustained capital flight over three decades means that capital flight had a role for the Philippines to lose the opportunities to achieve economic takeoff. Unless decisive policy actions are taken up to address enduring capital flight and manage the macroe...

  16. Capital productivity in industrialised economies: Evidence from error-correction model and lagrange multiplier tests

    Directory of Open Access Journals (Sweden)

    Trofimov Ivan D.

    2017-01-01

    Full Text Available The paper re-examines the “stylized facts” of the balanced growth in developed economies, looking specifically at capital productivity variable. The economic data is obtained from European Commission AMECO database, spanning 1961-2014 period. For a sample of 22 OECD economies, the paper applies univariate LM unit root tests with one or two structural breaks, and estimates error-correction and linear trend models with breaks. It is shown that diverse statistical patterns were present across economies and overall mixed evidence is provided as to the stability of capital productivity and balanced growth in general. Specifically, both upward and downward trends in capital productivity were present, while in several economies mean reversion and random walk patterns were observed. The data and results were largely in line with major theoretical explanations pertaining to capital productivity. With regard to determinants of the capital productivity movements, the structure of capital stock and the prices of capital goods were likely most salient.

  17. Debt Shifting and Thin-Capitalization Rules – German Experience and Alternative Approaches

    Directory of Open Access Journals (Sweden)

    Ruf Martin

    2015-09-01

    Full Text Available This paper presents the general design of thin-capitalization rules and summarizes the economic effects of such rules as identified in theoretical models. We review empirical studies providing evidence on the experience with (German thin-capitalization rules as well as on the adjustment of German multinationals to foreign thin-capitalization rules. Special emphasis is given to the development in Germany, because Germany went a long way in limiting interest deductibility by enacting a drastic change in its thin-capitalization rules in 2008, and because superb German data on multinational finance allows for testing several aspects consistently. We then discuss the experience of the Nordic countries with thin-capitalization rules. Briefly reviewing potential alternatives as well, we believe that the arm’s-length principle is administratively too costly and impracticable, whereas we argue that controlled-foreign-company rules might be another promising avenue for limiting internal debt shifting. Fundamental tax reforms towards a system with either "allowance for corporate equity" (ACE or a "comprehensive business income tax" (CBIT should also eliminate any thin-capitalization incentive.

  18. Sources of Regional Banks Capitalization

    Directory of Open Access Journals (Sweden)

    Olga Sergeevna Miroshnichenko

    2018-03-01

    Full Text Available Searching of sources to increase the capitalization of Russian banks is an important economic problem for both the national and regional economy. Moreover, a strong capital base allows to credit institutions to meet the demands of economic agents for banking service. The research focuses on the choice of sources of regulatory capital for the banks of Tyumen region in the context of changing supervisory requirements in the period of 2005–2016, in different phases of the business cycle. We apply econometric methods of statistical information using IBM SPSS Statistics software. We have calculated the individual correlations of regional banks’ capital with gross domestic product (GDP (excluding gross regional product (GRP and GRP (with the exception of the effect of GDP. These calculations have shown that the capital of regional banks is related only to GDP. The increase in the capital of regional banks is accompanied by a change in its structure: the share of authorized capital has halved, and the share of subordinated debt has grown. All sources of capital, other than the reserve fund, are related to GDP. Authorized capital is associated with the profit of profitable lending institutions; retained earnings in the capital of regional banks — with the aggregated amount of risks of the banking system of the Russian Federation. Subordinated debt, like capital as a whole, is negatively affected by the profitability of the banking sector. The change in the capital of regional banks is determined by the change in retained earnings, subordinated debt and reserve fund. Modelling of these relations has allowed to obtain a system of equations. This system synthesizes linear regression models of changing the capital of regional banks in the context of their sourcing. The results of this study are significant for theoretical justification and practical development of a balanced financial policy of regional banks. Our research will contribute to

  19. Minority games, evolving capitals and replicator dynamics

    International Nuclear Information System (INIS)

    Galla, Tobias; Zhang, Yi-Cheng

    2009-01-01

    We discuss a simple version of the minority game (MG) in which agents hold only one strategy each, but in which their capitals evolve dynamically according to their success and in which the total trading volume varies in time accordingly. This feature is known to be crucial for MGs to reproduce stylized facts of real market data. The stationary states and phase diagram of the model can be computed, and we show that the ergodicity breaking phase transition common for MGs, and marked by a divergence of the integrated response, is present also in this simplified model. An analogous majority game turns out to be relatively void of interesting features, and the total capital is found to diverge in time. Introducing a restraining force leads to a model akin to the replicator dynamics of evolutionary game theory, and we demonstrate that here a different type of phase transition is observed. Finally we briefly discuss the relation of this model with one strategy per player to more sophisticated minority games with dynamical capitals and several trading strategies per agent

  20. The Brazilian Public Health in Contemporary Capitalism.

    Science.gov (United States)

    Junqueira, Virgínia; Mendes, Áquilas N

    2018-01-01

    This article examines some political and economic facts that led to an intensification of austerity measures by the Brazilian government, including ones against the Unified Health System (SUS) and its progressive dismantling. In a country where fundamental human rights were never fully respected, nowadays social and labor rights are under severe attacks. The deepening of the capital crisis and the rise of interest-bearing capital dominance have been causing unemployment, social insecurity growth, and resulting public fund appropriation by the private capital. The Brazilian governments in the 1990s and 2000s have implemented deeper cuts in social policy expenditure, freezing security benefits, privatizing services, and prioritizing the payment of public debt interests. The right wing's project involves the demoralization of not only the Workers' Party but also the left as a whole, so that the adoption of austerity measures could be achieved without popular resistance. It is the duty of the Brazilian left wing to denounce such a project and to provoke firm initiatives to rebuild its bonds with the working class.