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Sample records for open wedge high

  1. Opening-wedge high tibial osteotomy: a seven - to twelve-year study

    PubMed Central

    PIPINO, GENNARO; INDELLI, PIER FRANCESCO; TIGANI, DOMENICO; MAFFEI, GIUSEPPE; VACCARISI, DAVIDE

    2016-01-01

    Purpose medial opening-wedge osteotomy is a widely performed procedure used to treat moderate isolated medial knee osteoarthritis. Historically, the literature has contained reports showing satisfactory mid-term results when accurate patient selection and precise surgical techniques were applied. This study was conducted to investigate the clinical and radiographic seven- to twelve-year results of opening-wedge high tibial osteotomy in a consecutive series of patients affected by varus knee malalignment with isolated medial compartment degenerative joint disease. Methods we reviewed a case series of 147 medial opening-wedge high tibial osteotomies at an average follow-up of 9.5 years. Endpoints for evaluation included the reporting of adverse effects, radiographic evidence of bone union, radiographic changes in the correction angle during union, and clinical and functional final outcomes. Results good or excellent results were obtained in 94% of the cases: the patients reported no major complications related to the opening-wedge high tibial osteotomy surgical technique, bone graft resorption, implant choice or postoperative rehabilitation protocol. At final follow-up, the average hip-knee angle was 4° of valgus without major loss of correction during the healing process. A statistically significant change in the patellar height was detected postoperatively, with a trend towards patella infera. Conclusions medial opening-wedge high tibial osteotomy is still a reliable method for correcting varus deformity while producing stable fixation, thus allowing satisfactory stability, adequate bone healing and satisfactory mid- to long-term results. Level of evidence Level IV, therapeutic cases series. PMID:27386441

  2. Unintended Rotational Changes of the Distal Tibia After Biplane Medial Open-Wedge High Tibial Osteotomy.

    PubMed

    Jang, Ki-Mo; Lee, Jong-Hee; Park, Hyung-Jun; Kim, Jeong Lae; Han, Seung-Beom

    2016-01-01

    This study involved 35 knees undergoing biplane medial open-wedge high tibial osteotomy (OWHTO) to assess the axial rotation of the distal tibia. The distal tibiae were internally rotated by 3.0° ± 7.1° after OWHTO. The opening width showed a Pearson correlation coefficient of -0.743 (P < .001), and the tuberosity osteotomy angle showed that of -0.678 (P < .001) with distal tibial rotation. However, changes in hip-knee-ankle angle, medial proximal tibial angle, and posterior tibial slope were not significantly correlated with the change in distal tibial rotation. In conclusion, there was an unintended tendency of increasing internal rotation of the distal tibia after biplane medial OWHTO, and this tendency was positively related to the opening width and tuberosity osteotomy angle.

  3. The validity of the classification for lateral hinge fractures in open wedge high tibial osteotomy.

    PubMed

    Nakamura, R; Komatsu, N; Murao, T; Okamoto, Y; Nakamura, S; Fujita, K; Nishimura, H; Katsuki, Y

    2015-09-01

    The objective of this study was to validate the efficacy of Takeuchi classification for lateral hinge fractures (LHFs) in open wedge high tibial osteotomy (OWHTO). In all 74 osteoarthritic knees (58 females, 16 males; mean age 62.9 years, standard deviation 7.5, 42 to 77) were treated with OWHTO using a TomoFix plate. The knees were divided into non-fracture (59 knees) and LHF (15 knees) groups, and the LHF group was further divided into Takeuchi types I, II, and III (seven, two, and six knees, respectively). The outcomes were assessed pre-operatively and one year after OWHTO. Pre-operative characteristics (age, gender and body mass index) showed no significant difference between the two groups. The mean Japanese Orthopaedic Association score was significantly improved one year after operation regardless of the presence or absence of LHF (p = 0.0015, p < 0.001, respectively). However, six of seven type I cases had no LHF-related complications; both type II cases had delayed union; and of six type III cases, two had delayed union with correction loss and one had overcorrection. These results suggest that Takeuchi type II and III LHFs are structurally unstable compared with type I. Cite this article: Bone Joint J 2015;97-B:1226-31. PMID:26330589

  4. Evaluation of Patellar Position before and After Medial Opening Wedge High Tibial Osteotomy: Radiographic and Computed Tomography Findings

    PubMed Central

    Moghtadaei, Mehdi; Otoukesh, Babak; Bodduhi, Bahram; Ahmadi, Keyvan; Yeganeh, Ali

    2016-01-01

    Introduction: Genovarum is a common orthopedic problem. Its optimal prompt treatment is an issue of importance. Aim: This study was conducted to determine the radiographic changes in patella bone before and after open wedge high tibial osteotomy. Material and Methods: In this quasi-experimental study, 43 patients were enrolled and underwent open wedge high tibial osteotomy and the radiographic and CT-scan indices including Q-Angle, Congruence Angle, Insall-Salvati index, and TTTG were measured and compared before and after surgery. Results: The result revealed that all indices including Q-Angle, Congruence Angle, Insull-Salvati index, and TTTG were not significantly differed across the study (P > 0.05). There was no difference between DLFA values before and after the operation (P> 0.05), while MPTA values were significantly different before and after operation (p <0.001). Conclusions: Totally it may be concluded that imaging indices are not differed after open wedge high tibial osteotomy and monitoring for them is not necessary and they would have no prognostic role. PMID:27703292

  5. Medial opening wedge high tibial osteotomy alters knee moments in multiple planes during walking and stair ascent.

    PubMed

    Leitch, Kristyn M; Birmingham, Trevor B; Dunning, Cynthia E; Giffin, J Robert

    2015-07-01

    Medial opening wedge high tibial osteotomy is a surgical procedure intended to redistribute loads on the knee in patients with medial compartment knee osteoarthritis (OA). The surgery may affect moments in multiple planes during ambulation, with potential beneficial or detrimental effects on joint loads. The objective of this study was to investigate three-dimensional external knee moments before and after medial opening wedge high tibial osteotomy during level walking and during stair ascent. Fourteen patients with varus alignment and osteoarthritis primarily affecting the medial compartment of the tibiofemoral joint were assessed. Three-dimensional motion analyses during level walking and stair ascent was evaluated using inverse dynamics before, 6 and 12 months after surgery. Mean changes at 12 months suggested decreases in the peak knee adduction, flexion and internal rotation moments, with standardized response means ranging from 0.15 to 2.54. These decreases were observed despite increases in speed. Changes in alignment were associated with changes in the adduction and internal rotation moments, but not the flexion moment. Both pre- and postoperatively, the peak knee adduction moment was significantly lower (p=0.001) during stair ascent than during level walking, while the flexion and internal rotation moments were significantly higher (p<0.01). There were no changes in the knee moments on the non-surgical limb. Medial opening wedge high tibial osteotomy is associated with sustained (12 months) changes in knee moments in all three planes of motion during ambulation, suggesting substantial alterations of the loads on the knee during ambulation.

  6. Modified biplanar open-wedge high tibial osteotomy with rigid locking plate to treat varus knee*

    PubMed Central

    Zhang, Hai-ning; Zhang, Jie; Lv, Cheng-yu; Leng, Ping; Wang, Ying-zhen; Wang, Xiang-da; Wang, Chang-yao

    2009-01-01

    Objective: To introduce and characterize the modified biplanar opening high tibial osteotomy with rigid fixation to treat varus knee in young and active patients. Methods: Between June 2001 to July 2008, 18 patients with monocompartmental degeneration of the knee combined with a varus malalignment of the leg had the modified biplanar opening high tibial osteotomy and the osteotomy was fixed with the locking plates (Locking Compression Plate System). The mean varus deformity before operation was 11.5° (5°~19°) and no degenerative changes were found in other departments. Stability of the knee was normal in 15 patients, but ruptures in anterior cruciate ligaments or lateral collateral ligament were presented in the remaining 3 patients. Preoperative symptom was mainly limited in the pain of medial compartment. The preoperative and follow-up data for the range of motion and Lysholm score were determined. Subjective satisfactory examination was also applied to the patients for the operation they selected. Results: All of the patients were followed up with an average of 32.5 months (12~82 months). There was no ununion or delayed union in this group during the follow-up period. No complications like broken plate, nerve injury, or blood vessel injury occurred. The postoperative average corrected degree was 9.5° (5.5°~18°). No degenerations developed in the three departments of the knee. The Lysholm scores before and after surgery were 42.5 and 77.5, respectively (P<0.01). The overall fineness rate was 83.3%. The subjective satisfactory survey demonstrated that about 83.3% patients showed satisfactory on the operation. There was no obvious difference in the range of motion before and after operation, but significant changes were found in the Lysholm score and varus degree from preoperative to follow-up. Conclusion: Proximal opening high tibial osteotomy performed in conjunction with the special rigid locking plate yielded good results for symptomatic genu varum. This

  7. A predictive factor for acquiring an ideal lower limb realignment after opening-wedge high tibial osteotomy.

    PubMed

    Bito, Haruhiko; Takeuchi, Ryohei; Kumagai, Ken; Aratake, Masato; Saito, Izumi; Hayashi, Riku; Sasaki, Yohei; Aota, Yoichi; Saito, Tomoyuki

    2009-04-01

    Obtaining a correct postoperative limb alignment is an important factor in achieving a successful clinical outcome after an opening-wedge high tibial osteotomy (OWHTO). To better predict some of the aspects that impact upon the clinical outcomes following this procedure, including postoperative correction loss and over correction, we examined the changes in the frontal plane of the lower limb in a cohort of patients who had undergone OWHTO using radiography. Forty-two knees from 33 patients (23 cases of osteoarthritis and 10 of osteonecrosis) underwent a valgus realignment OWHTO procedure and were radiographically assessed for changes that occurred pre- and post-surgery. The mean femorotibial angle (FTA) was found to be 182.1 +/- 2.0 degrees (12 +/- 2.0 anatomical varus angulation) preoperatively and 169.6 +/- 2.4 degrees (10.4 +/- 2.4 anatomical valgus angulation) postoperatively. These measurements thus revealed significant changes in the weight bearing line ratio (WBL), femoral axis angle (FA), tibial axis angle (TA), tibia plateau angle (TP), tibia vara angle (TV) and talar tilt angle (TT) following OWHTO. In contrast, no significant change was found in the weight bearing line angle (WBLA) after these treatments. To assess the relationship between the correction angle and these indexes, 42 knees were divided into the following three groups according to the postoperative FTA; a normal correction group (168 degrees < or = FTA < or = 172 degrees ), an over-correction group (FTA < 168 degrees ), and an under-correction group (FTA > 172 degrees ). There were significant differences in the delta angle [DA; calculated as (pre FTA - post FTA) - (pre TV - post TV)] among each group of patients. Our results thus indicate a negative correlation between the DA and preoperative TA (R(2) = 0.148, p < 0.05). Hence, given that the correction errors in our patients appear to negatively correlate with the preoperative TA, postoperative malalignments are likely to be predictable

  8. Biplanar Open Wedge High Tibial Osteotomy in the Medial Compartment Osteoarthritis of the Knee Joint: Comparison between the Aescula and TomoFix Plate

    PubMed Central

    Lee, Byoung-Joo; Kim, Joon-Woo; Yoon, Seong-Dae

    2015-01-01

    Background The purpose of this study was to compare the results of Aescula and TomoFix plates used for biplanar open wedge high tibial osteotomy in medial osteoarthritis of the knee joint with varus deformity. Methods A consecutive series of 50 cases of biplanar open wedge high tibial osteotomy were evaluated retrospectively. Group A contained 25 cases treated by using the Aescula plate, and group T contained 25 cases treated by using the TomoFix plate. Full weight-bearing was permitted at 6 weeks after surgery in group A and at 2 weeks in group T. Clinical evaluations were performed at the final follow-up by using postoperative knee scores and functional scores. Radiographic analysis included postoperative mechanical femur-tibia angle, change in posterior tibial slope angle, and complications related to implants. The mean follow-up periods were 30 months in group A and 26 months in group T. Results The knee and functional scores were improved at the final follow-up in both groups (p < 0.05), but no differences were observed between the two groups (p > 0.05). An acceptable correction angle was obtained in 52% of group A and in 84% of group T (p = 0.015). Change in posterior tibial slope angle was larger in group A than in group T (p < 0.001), showing better maintenance of posterior tibial slope in group T. In group A, there were 3 cases of screw loosening and 4 cases of delayed union. In addition, there were residual varus deformities in 7 cases (6 in group A and 1 in group T). Conclusions This study shows that firm fixation using a TomoFix plate for open wedge high tibial osteotomy produces better radiologic results and a low complication rate than those of the Aescula spacer plate. PMID:26217464

  9. The statics of the wedge-shaped jar opener

    NASA Astrophysics Data System (ADS)

    Donolato, C.

    2015-11-01

    This paper analyzes the static equilibrium of a simple jar opener on the basis of rigid-body mechanics with friction. The opener-lid system is described as a disk lying inside a wedge, where only one side has friction; the disk is assumed to be acted upon by a wedging force and a torque. The resulting equilibrium equations have an exact solution that yields the non-sliding conditions for the disk as functions of applied forces and system parameters.

  10. Opening wedge osteotomies for correction of hallux valgus: a review of wedge plate fixation.

    PubMed

    Smith, W Bret; Hyer, Christopher F; DeCarbo, William T; Berlet, Gregory C; Lee, Thomas H

    2009-12-01

    Osteotomy of the proximal metatarsal for the correction of moderate to severe hallux valgus deformity is commonly performed. The purpose of this study is to review the early results of a technique for the correction of hallux valgus, an opening wedge osteotomy of the proximal first metatarsal with opening wedge plate fixation. A review was performed of the results of 47 patients (49 feet) who underwent correction of hallux valgus with proximal metatarsal opening wedge osteotomy. All osteotomies were secured with plate fixation on the medial side. Evaluation consisted of preoperative and postoperative radiographic as well as clinical evaluations. Mean corrections of 7 degrees were achieved for the 1-2 intermetatarsal angles. Fourteen complications occurred, 6 of which involved mild hardware irritation and did not affect outcome. Four nonunions or delayed unions were identified. The authors find the opening wedge osteotomy of the proximal first metatarsal to be a technically straightforward procedure for correcting moderate to severe hallux valgus. The correction obtained is comparable to other described techniques. PMID:20400425

  11. Minimizing Alteration of Posterior Tibial Slope During Opening Wedge High Tibial Osteotomy: a Protocol with Experimental Validation in Paired Cadaveric Knees

    PubMed Central

    Westermann, Robert W; DeBerardino, Thomas; Amendola, Annunziato

    2014-01-01

    Introduction The High Tibial Osteotomy (HTO) is a reliable procedure in addressing uni- compartmental arthritis with associated coronal deformities. With osteotomy of the proximal tibia, there is a risk of altering the tibial slope in the sagittal plane. Surgical techniques continue to evolve with trends towards procedure reproducibility and simplification. We evaluated a modification of the Arthrex iBalance technique in 18 paired cadaveric knees with the goals of maintaining sagittal slope, increasing procedure efficiency, and decreasing use of intraoperative fluoroscopy. Methods Nine paired cadaveric knees (18 legs) underwent iBalance medial opening wedge high tibial osteotomies. In each pair, the right knee underwent an HTO using the modified technique, while all left knees underwent the traditional technique. Independent observers evaluated postoperative factors including tibial slope, placement of hinge pin, and implant placement. Specimens were then dissected to evaluate for any gross muscle, nerve or vessel injury. Results Changes to posterior tibial slope were similar using each technique. The change in slope in traditional iBalance technique was -0.3° ±2.3° and change in tibial slope using the modified iBalance technique was -0.4° ±2.3° (p=0.29). Furthermore, we detected no differences in posterior tibial slope between preoperative and postoperative specimens (p=0.74 traditional, p=0.75 modified). No differences in implant placement were detected between traditional and modified techniques. (p=0.85). No intraoperative iatrogenic complications (i.e. lateral cortex fracture, blood vessel or nerve injury) were observed in either group after gross dissection. Discussion & Conclusions Alterations in posterior tibial slope are associated with HTOs. Both traditional and modified iBalance techniques appear reliable in coronal plane corrections without changing posterior tibial slope. The present modification of the Arthrex iBalance technique may increase the

  12. Anterolateral Biplanar Proximal Tibial Opening-Wedge Osteotomy.

    PubMed

    Dean, Chase S; Chahla, Jorge; Moulton, Samuel G; Nitri, Marco; Serra Cruz, Raphael; LaPrade, Robert F

    2016-06-01

    Proximal tibial anterolateral opening-wedge osteotomies have been reported to achieve successful biplanar lower-extremity realignment. Indications for a proximal tibial anterolateral osteotomy include symptomatic genu recurvatum with genu valgus alignment, usually in patients with a flat sagittal-plane tibial slope. The biplanar approach is able to simultaneously address both components of a patient's malalignment with a single procedure. The correction amount is verified with spacers and intraoperative imaging, while correction of the patient's heel height is simultaneously measured. A plate is secured into the osteotomy site, and the site is filled with bone allograft. The anterolateral tibial osteotomy has been reported to be an effective surgical procedure for correcting concomitant genu recurvatum and genu valgus malalignment. PMID:27656374

  13. High-energy rate forgings of wedges :

    SciTech Connect

    Reynolds, Thomas Bither; Everhart, Wesley; Switzner, Nathan T; Balch, Dorian K.; San Marchi, Christopher W.

    2014-05-01

    The wedge geometry is a simple geometry for establishing a relatively constant gradient of strain in a forged part. The geometry is used to establish gradients in microstructure and strength as a function of strain, forging temperature, and quenching time after forging. This geometry has previously been used to benchmark predictions of strength and recrystallization using Sandias materials model for type 304L austenitic stainless steel. In this report, the processing conditions, in particular the times to forge and quench the forged parts, are summarized based on information recorded during forging on June 18, 2013 of the so-called wedge geometry from type 316L and 21Cr-6Ni-9Mn austenitic stainless steels.

  14. Vertebral Osteotomies in Ankylosing Spondylitis-Comparison of Outcomes Following Closing Wedge Osteotomy versus Opening Wedge Osteotomy: A Systematic Review.

    PubMed

    Ravinsky, Robert A; Ouellet, Jean-Albert; Brodt, Erika D; Dettori, Joseph R

    2013-04-01

    Study Design Systematic review. Study Rationale To seek out and assess the best quality evidence available comparing opening wedge osteotomy (OWO) and closing wedge osteotomy (CWO) in patients with ankylosing spondylitis to determine whether their results differ with regard to several different subjective and objective outcome measures. Objective The aim of this study is to determine whether there is a difference in subjective and objective outcomes when comparing CWO and OWO in patients with ankylosing spondylitis suffering from clinically significant thoracolumbar kyphosis with respect to quality-of-life assessments, complication risks, and the amount of correction of the spine achieved at follow-up. Methods A systematic review was undertaken of articles published up to July 2012. Electronic databases and reference lists of key articles were searched to identify studies comparing effectiveness and safety outcomes between adult patients with ankylosing spondylitis who received closing wedge versus opening wedge osteotomies. Studies that included pediatric patients, polysegmental osteotomies, or revision procedures were excluded. Two independent reviewers assessed the strength of evidence using the GRADE criteria and disagreements were resolved by consensus. Results From a total of 67 possible citations, 4 retrospective cohorts (class of evidence III) met our inclusion criteria and form the basis for this report. No differences in Oswestry Disability Index, visual analog scale for pain, Scoliosis Research Society (SRS)-24 score, SRS-22 score, and patient satisfaction were reported between the closing and opening wedge groups across two studies. Regarding radiological outcomes following closing versus opening osteotomies, mean change in sagittal vertical axis ranged from 8.9 to 10.8 cm and 8.0 to 10.9 cm, respectively, across three studies; mean change in lumbar lordosis ranged from 36 to 47 degrees and 19 to 41 degrees across four studies; and mean change

  15. 50 CFR Figure 17 to Part 223 - Boone Wedge Cut Escape Opening

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false Boone Wedge Cut Escape Opening 17 Figure 17 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS THREATENED MARINE AND ANADROMOUS SPECIES...

  16. Demonstration of Color Separation with 2ω KDP Wedge in High Power Laser Facilities

    NASA Astrophysics Data System (ADS)

    Wang, Fang; Li, Fu-Quan; Han, Wei; Feng, Bin; Zhou, Li-Dan; Jia, Huai-Ting; Cao, Hua-Bao

    2014-01-01

    A 2ω wedge design is proposed with KDP crystal to disperse the unconverted light away from the target in a high power laser facility for inertial confinement fusion. The ultraviolet B-integral problem is released, and about 1.2 times in color separation angle is achieved according to both theoretical and experimental investigations when compared with conventional 3ω wedge. The frequency conversion efficiency is unaffected when the wedge is along the non-sensitive axis of the tripler.

  17. Proximal Tibia Medial Biplanar Retrotubercle Open Wedge Osteotomy for Varus Knees with Medial Gonarthrosis

    PubMed Central

    Türkmen, İsmail; Esenkaya, İrfan; Ünay, Koray; Türkmensoy, Fatih; Özkut, Afşar Timuçin

    2014-01-01

    Objectives: The purpose of this study is to evaluate the early results of proximal tibia medial biplanar retrotubercle open wedge osteotomy for varus gonarthrosis and compare the results with the literatüre. Methods: The results of proximal tibia medial biplanar retrotubercle open wedge osteotomy for 23 knees of 22 patients with medial gonarthrosis were evaluated clinically and radiologically. Results: Twenty of the patients were female and two were male. Mean age of the patients was 56.24; mean boy mass index was 31.95 and preoperative HSS (Hospital for Special Surgery) score was 68.7. Mean tibiofemoral axis was 186.39° and mean Insall-Salvatti index value was 1.04 preoperatively. Mean follow up period was 30.19 months. Mean HSS score was 86.48, femorotibial anatomic axis angle was 175° and Insall-Salvati index value 1.06 during the last follow-up. The improvement of the HSS score and the femorotibial anatomic axis angle was statistically significant. However, the change in Insall Salvati index values was statistically insignificant. Nonfatal pulmonary embolus in 1 patient, and deep vein thrombosis that occured one year after the procedure in 1 patient, rhabdomyolysis in 1 patient and loss of correction (relapse) in 1 patient were encountered as complications. Conclusion: Our results show that proximal tibia medial biplanar retrotubercle open wedge osteotomy improves the frontal and sagittal plane deformities without changing the patellar tendon length. Hence, possible patellofemoral problems are prevented and the clinical results are improved.

  18. Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges.

    PubMed

    Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

    2016-05-01

    Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10(-3) S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10(-1) S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front. PMID:27386526

  19. Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges.

    PubMed

    Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

    2016-05-01

    Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10(-3) S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10(-1) S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front.

  20. Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges

    PubMed Central

    Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

    2016-01-01

    Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10−3 S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10−1 S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front. PMID:27386526

  1. Monte Carlo Simulation of a 6 MV X-Ray Beam for Open and Wedge Radiation Fields, Using GATE Code.

    PubMed

    Bahreyni-Toosi, Mohammad-Taghi; Nasseri, Shahrokh; Momennezhad, Mahdi; Hasanabadi, Fatemeh; Gholamhosseinian, Hamid

    2014-10-01

    The aim of this study is to provide a control software system, based on Monte Carlo simulation, and calculations of dosimetric parameters of standard and wedge radiation fields, using a Monte Carlo method. GATE version 6.1 (OpenGATE Collaboration), was used to simulate a compact 6 MV linear accelerator system. In order to accelerate the calculations, the phase-space technique and cluster computing (Condor version 7.2.4, Condor Team, University of Wisconsin-Madison) were used. Dosimetric parameters used in treatment planning systems for the standard and wedge radiation fields (10 cm × 10 cm to 30 cm × 30 cm and a 60° wedge), including the percentage depth dose and dose profiles, were measured by both computational and experimental methods. Gamma index was applied to compare calculated and measured results with 3%/3 mm criteria. Gamma index was applied to compare calculated and measured results. Almost all calculated data points have satisfied gamma index criteria of 3% to 3 mm. Based on the good agreement between calculated and measured results obtained for various radiation fields in this study, GATE may be used as a useful tool for quality control or pretreatment verification procedures in radiotherapy.

  2. Monte Carlo Simulation of a 6 MV X-Ray Beam for Open and Wedge Radiation Fields, Using GATE Code

    PubMed Central

    Bahreyni-Toosi, Mohammad-Taghi; Nasseri, Shahrokh; Momennezhad, Mahdi; Hasanabadi, Fatemeh; Gholamhosseinian, Hamid

    2014-01-01

    The aim of this study is to provide a control software system, based on Monte Carlo simulation, and calculations of dosimetric parameters of standard and wedge radiation fields, using a Monte Carlo method. GATE version 6.1 (OpenGATE Collaboration), was used to simulate a compact 6 MV linear accelerator system. In order to accelerate the calculations, the phase-space technique and cluster computing (Condor version 7.2.4, Condor Team, University of Wisconsin–Madison) were used. Dosimetric parameters used in treatment planning systems for the standard and wedge radiation fields (10 cm × 10 cm to 30 cm × 30 cm and a 60° wedge), including the percentage depth dose and dose profiles, were measured by both computational and experimental methods. Gamma index was applied to compare calculated and measured results with 3%/3 mm criteria. Gamma index was applied to compare calculated and measured results. Almost all calculated data points have satisfied gamma index criteria of 3% to 3 mm. Based on the good agreement between calculated and measured results obtained for various radiation fields in this study, GATE may be used as a useful tool for quality control or pretreatment verification procedures in radiotherapy. PMID:25426430

  3. Monte Carlo Simulation of a 6 MV X-Ray Beam for Open and Wedge Radiation Fields, Using GATE Code.

    PubMed

    Bahreyni-Toosi, Mohammad-Taghi; Nasseri, Shahrokh; Momennezhad, Mahdi; Hasanabadi, Fatemeh; Gholamhosseinian, Hamid

    2014-10-01

    The aim of this study is to provide a control software system, based on Monte Carlo simulation, and calculations of dosimetric parameters of standard and wedge radiation fields, using a Monte Carlo method. GATE version 6.1 (OpenGATE Collaboration), was used to simulate a compact 6 MV linear accelerator system. In order to accelerate the calculations, the phase-space technique and cluster computing (Condor version 7.2.4, Condor Team, University of Wisconsin-Madison) were used. Dosimetric parameters used in treatment planning systems for the standard and wedge radiation fields (10 cm × 10 cm to 30 cm × 30 cm and a 60° wedge), including the percentage depth dose and dose profiles, were measured by both computational and experimental methods. Gamma index was applied to compare calculated and measured results with 3%/3 mm criteria. Gamma index was applied to compare calculated and measured results. Almost all calculated data points have satisfied gamma index criteria of 3% to 3 mm. Based on the good agreement between calculated and measured results obtained for various radiation fields in this study, GATE may be used as a useful tool for quality control or pretreatment verification procedures in radiotherapy. PMID:25426430

  4. A 5° medial wedge reduces frontal but not saggital plane motion during jump landing in highly trained women athletes

    PubMed Central

    Joseph, Michael F; Denegar, Craig R; Horn, Elaine; MacDougall, Bradley; Rahl, Michael; Sheehan, Jessica; Trojian, Thomas; Anderson, Jeffery M; Clark, James E; Kraemer, William J

    2010-01-01

    Lower extremity mechanics during landing have been linked to traumatic and nontraumatic knee injuries, particularly in women’s athletics. The effects of efforts to mitigate these risks have not been fully elucidated. We previously reported that a 5° medial wedge reduced ankle eversion and knee valgus. In the present report we further investigated the effect of a 5° medial wedge inserted in the shoes of female athletes on frontal plane hip motion, as well as ankle, knee, hip, and trunk saggital plane motion during a jump landing task. Kinematic data were obtained from 10 intercollegiate female athletes during jump landings from a 31 cm platform with and without a 5° medial wedge. Hip adduction was reduced 1.98° (95% CI 0.97–2.99°) by the medial wedge but saggital plane motions were unaffected. A 5° medial wedge reduces frontal plane motion and takes the knee away from a position associated with anterior cruciate ligament injury and patellofemoral pain syndrome. Although frontal plane motion was not captured it is unlikely to have increased in a bilateral landing task. Thus, it is likely that greater muscle forces were generated in these highly trained athletes to dissipate ground reaction forces when a medial wedge was in place. Additional investigation in younger and lesser trained athletes is warranted to assess the impact of orthotic devices on knee joint mechanics. PMID:24198539

  5. PRE-OPERATIVE PLANNING AND SURGICAL TECHNIQUE OF THE OPEN WEDGE SUPRACONDYLAR OSTEOTOMY FOR CORRECTION OF VALGUS KNEE AND FIXATION WITH A FIXED-ANGLE IMPLANT

    PubMed Central

    Paccola, Cleber Antonio Jansen

    2015-01-01

    The step-by-step preoperative planning for supracondylar opening wedge osteotomy of the femur for precise correction of the load axis of the lower limb using a fixed-angle implant (95° AO blade plate) is presented. The surgical technique and the use of a bone graft from the same site for filling in the defect are also presented. PMID:27026976

  6. Gas flux dynamics in high arctic permafrost polygon and ice wedge active layer soil; microbial feedback implications

    NASA Astrophysics Data System (ADS)

    Mykytczuk, N. C.; Stackhouse, B. T.; Bennett, P.; Lamarche-Gagnon, G.; Hettich, R. L.; Phelps, T. J.; Layton, A.; Pfiffner, S. M.; Allan, J.; Vishnivetskaya, T. A.; Chourey, K.; Whyte, L.; Onstott, T. C.

    2011-12-01

    Temperatures in the Arctic may increase 4-8°C over the next 100 years, thereby increasing the depth of the active layer (AL) and thawing the underlying permafrost, with ice wedges in particular acting as an early indicator, a bellwether, for changing permafrost. Although data on CO2 and CH4 fluxes have been studied along with microbial diversity of AL and permafrost environments, the relationship between methanogenic, methanotrophic and heterotrophic in situ activities within the AL and CO2 and CH4 fluxes as a function of temperature has not been delineated. Defining these relationships is critical for accurately modeling the extent and rate of + / - feedback in global climate models. Initial field investigations of diurnal CO2 and CH4 flux from permafrost and ice-wedge AL soils were conducted during July on Axel Heiberg Island in the Canadian high arctic. The AL soils (68-69 cm depth) were completely thawed while ambient air temperatures were between 9 and 27°C. The AL soils above the ice wedges had a higher water content and finer texture than the polygon AL soils. Diurnal patterns using in situ flux chambers and a Picarro C-13 CO2 cavity ring-down spectrometer recorded net outward flux of CO2 (3.2 to 8.8 g/m2/day) and consumption of atmospheric CH4 (-2.2 mg/m2/day) from the AL surfaces. Gas flux from the ice wedge soil surface were in a similar range as the polygon soil surface, having slightly higher maximal flux of CO2 (10.4 g/m2/day) and net efflux of CH4 (-2.2 to 14 mg/m2/day). Using a vertical probe, gas flux below the surface measured higher amounts of CO2 with increasing depth ranging from 10.4 to 21.4 g/m2/day in the polygon soils vs. 10 to 28.5 g/m2/day in the ice wedge soils. Through the same profile, the CH4 concentration decreased from 0.59 ppmv to < 0.1 ppmv within 30 cm of the surface in the ice wedge and from 1.1 to 0.54 ppmv at the base of the polygon AL. The δ13C of the CO2 efflux from the surface were consistent with microbial activity

  7. Nano Conductive Ceramic Wedged Graphene Composites as Highly Efficient Metal Supports for Oxygen Reduction

    PubMed Central

    Wu, Peng; Lv, Haifeng; Peng, Tao; He, Daping; Mu, Shichun

    2014-01-01

    A novel conductive ceramic/graphene nanocomposite is prepared to prohibit the re-stacking of reduced graphene oxide (RGO) by wedging zirconium diboride (ZrB2) nanoparticles (NPs) into multiple layer nanosheets using a simple solvothermal method. Surprisingly, the RGO/ZrB2 nanocomposite supported Pt NPs shows very excellent catalytic activity. Its electrochemical surface area (ECSA) is up to 148 m2g−1 (very approaches the geometry surface area of 155 m2g−1), much greater than that of the previous report (usually less than 100 m2g−1). The mass activity is as high as 16.8 A/g−1, which is almost 2 times and 5 times that of Pt/RGO (8.6 A/g−1) and Pt/C (3.2 A/g−1), respectively, as benchmarks. Moreover, after 4000 cycles the catalyst shows only 61% of ECSA loss, meaning a predominantly electrochemical stability. The remarkably improved electrochemical properties with much high Pt utilization of the new catalyst show a promising application in low temperature fuel cells and broader fields. PMID:24495943

  8. Nonlinear thermal and moisture response of ice-wedge polygons to permafrost disturbance increases heterogeneity of high Arctic wetland

    NASA Astrophysics Data System (ADS)

    Godin, Etienne; Fortier, Daniel; Lévesque, Esther

    2016-03-01

    Low-center polygonal terrains with gentle sloping surfaces and lowlands in the high Arctic have a potential to retain water in the lower central portion of ice-wedge polygons and are considered high-latitude wetlands. Such wetlands in the continuous permafrost regions have an important ecological role in an otherwise generally arid region. In the valley of the glacier C-79 on Bylot Island (Nunavut, Canada), thermal erosion gullies were rapidly eroding the permafrost along ice wedges affecting the integrity of the polygons by breaching and collapsing the surrounding rims. Intact polygons were characterized by a relative homogeneity in terms of topography, snow cover, maximum active layer thaw depth, ground moisture content and vegetation cover (where eroded polygons responded nonlinearly to perturbations, which resulted in differing conditions in the latter elements). The heterogeneous nature of disturbed terrains impacted active layer thickness, ground ice aggradation in the upper portion of permafrost, soil moisture, vegetation dynamics and carbon storage.

  9. Rethinking wedges

    NASA Astrophysics Data System (ADS)

    Davis, Steven J.; Cao, Long; Caldeira, Ken; Hoffert, Martin I.

    2013-03-01

    Abstract Stabilizing CO2 emissions at current levels for fifty years is not consistent with either an atmospheric CO2 concentration below 500 ppm or global temperature increases below 2 °C. Accepting these targets, solving the climate problem requires that emissions peak and decline in the next few decades, and ultimately fall to near zero. Phasing out emissions over 50 years could be achieved by deploying on the order of 19 'wedges', each of which ramps up linearly over a period of 50 years to ultimately avoid 1 GtC y-1 of CO2 emissions. But this level of mitigation will require affordable carbon-free energy systems to be deployed at the scale of tens of terawatts. Any hope for such fundamental and disruptive transformation of the global energy system depends upon coordinated efforts to innovate, plan, and deploy new transportation and energy systems that can provide affordable energy at this scale without emitting CO2 to the atmosphere. 1. Introduction In 2004, Pacala and Socolow published a study in Science arguing that '[h]umanity can solve the carbon and climate problem in the first half of this century simply by scaling up what we already know how to do' [1]. Specifically, they presented 15 options for 'stabilization wedges' that would grow linearly from zero to 1 Gt of carbon emissions avoided per year (GtC y-1 1 Gt = 1012 kg) over 50 years. The solution to the carbon and climate problem, they asserted, was 'to deploy the technologies and/or lifestyle changes necessary to fill all seven wedges of the stabilization triangle'. They claimed this would offset the growth of emissions and put us on a trajectory to stabilize atmospheric CO2 concentration at 500 ppm if emissions decreased sharply in the second half of the 21st century. The wedge concept has proven popular as an analytical tool for considering the potential of different technologies to reduce CO2 emissions. In the years since the paper was published, it has been cited more than 400 times, and

  10. Long-term outcomes of wedge resection at the limbus for high irregular corneal astigmatism after repaired corneal laceration

    PubMed Central

    Du, Jun; Zheng, Guang-Ying; Wen, Cheng-Lin; Zhang, Xiao-Fang; Zhu, Yu

    2016-01-01

    AIM To evaluate the clinical value of wedge resection at corneal limbus in patients with traumatic corneal scarring and high irregular astigmatism. METHODS Patients with traumatic corneal astigmatism received wedge resection at least 6mo after suture removal from corneal wound. The uncorrected distance visual acuities (UCVA) and best corrected distance visual acuities (BCVA), pre- and post-operation astigmatism, spherical equivalent (SE), safety and complications were evaluated. RESULTS Ten eyes (10 patients) were enrolled in this study. Mean follow-up time after wedge resection was 37.8±15.4mo (range, 20-61mo). The mean UCVA improved from +1.07±0.55 logMAR to +0.43±0.22 logMAR (P=0.000) and the mean BCVA from +0.50±0.30 logMAR to +0.15±0.17 logMAR (P=0.000). The mean astigmatism power measured by retinoscopy was -2.03±2.27 D postoperatively and -2.83±4.52 D preoperatively (P=0.310). The mean SE was -0.74±1.61 D postoperatively and -0.64±1.89 D preoperatively (P=0.601). Two cases developed mild pannus near the sutures. No corneal perforation, infectious keratitis or wound gape occurred. CONCLUSION Corneal-scleral limbal wedge resection with compression suture is a safe, effective treatment for poor patients with high irregular corneal astigmatism after corneal-scleral penetrating injury. Retinoscopy can prove particularly useful for high irregular corneal astigmatism when other measurements are not amenable. PMID:27366685

  11. Viscid-inviscid interaction associated with incompressible flow past wedges at high Reynolds number

    NASA Technical Reports Server (NTRS)

    Warpinski, N. R.; Chow, W. L.

    1977-01-01

    An analytical method is suggested for the study of the viscid inviscid interaction associated with incompressible flow past wedges with arbitrary angles. It is shown that the determination of the nearly constant pressure (base pressure) prevailing within the near wake is really the heart of the problem, and the pressure can only be established from these interactive considerations. The basic free streamline flow field is established through two discrete parameters which adequately describe the inviscid flow around the body and the wake. The viscous flow processes such as the boundary layer buildup, turbulent jet mixing, and recompression are individually analyzed and attached to the inviscid flow in the sense of the boundary layer concept. The interaction between the viscous and inviscid streams is properly displayed by the fact that the aforementioned discrete parameters needed for the inviscid flow are determined by the viscous flow condition at the point of reattachment. It is found that the reattachment point behaves as a saddle point singularity for the system of equations describing the recompressive viscous flow processes, and this behavior is exploited for the establishment of the overall flow field. Detailed results such as the base pressure, pressure distributions on the wedge, and the geometry of the wake are determined as functions of the wedge angle.

  12. Rethinking wedges

    NASA Astrophysics Data System (ADS)

    Davis, Steven J.; Cao, Long; Caldeira, Ken; Hoffert, Martin I.

    2013-03-01

    Abstract Stabilizing CO2 emissions at current levels for fifty years is not consistent with either an atmospheric CO2 concentration below 500 ppm or global temperature increases below 2 °C. Accepting these targets, solving the climate problem requires that emissions peak and decline in the next few decades, and ultimately fall to near zero. Phasing out emissions over 50 years could be achieved by deploying on the order of 19 'wedges', each of which ramps up linearly over a period of 50 years to ultimately avoid 1 GtC y-1 of CO2 emissions. But this level of mitigation will require affordable carbon-free energy systems to be deployed at the scale of tens of terawatts. Any hope for such fundamental and disruptive transformation of the global energy system depends upon coordinated efforts to innovate, plan, and deploy new transportation and energy systems that can provide affordable energy at this scale without emitting CO2 to the atmosphere. 1. Introduction In 2004, Pacala and Socolow published a study in Science arguing that '[h]umanity can solve the carbon and climate problem in the first half of this century simply by scaling up what we already know how to do' [1]. Specifically, they presented 15 options for 'stabilization wedges' that would grow linearly from zero to 1 Gt of carbon emissions avoided per year (GtC y-1 1 Gt = 1012 kg) over 50 years. The solution to the carbon and climate problem, they asserted, was 'to deploy the technologies and/or lifestyle changes necessary to fill all seven wedges of the stabilization triangle'. They claimed this would offset the growth of emissions and put us on a trajectory to stabilize atmospheric CO2 concentration at 500 ppm if emissions decreased sharply in the second half of the 21st century. The wedge concept has proven popular as an analytical tool for considering the potential of different technologies to reduce CO2 emissions. In the years since the paper was published, it has been cited more than 400 times, and

  13. Radial wedge flange clamp

    DOEpatents

    Smith, Karl H.

    2002-01-01

    A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

  14. Large Erosional Features on the Cascadia Accretionary Wedge Imaged with New High-Resolution Multibeam Bathymetry and Seismic Datasets

    NASA Astrophysics Data System (ADS)

    Beeson, J. W.; Goldfinger, C.

    2013-12-01

    Utilizing new high resolution multibeam bathymetric data along with chirp sub-bottom and multichannel seismic reflection (MCS) data, we identified remarkable erosional features on the toe of the Cascadia accretionary wedge near Willapa Canyon, offshore Washington, USA. Bathymetric data was compiled from the Cascadia Open-Access Seismic Transects (COAST) cruise and from the site survey cruise for the Cascadia Initiative. These features loosely resemble slope failures of the frontal thrust, but can be distinguished from such failures by several key features: They incise the crest of the frontal thrust and encompass the landward limb; They have floors below the level of the abyssal plain, similar to plunge pool morphology; They show no evidence of landslide blocks at the base of the slope indicative of block sliding. The features where likely formed during the latest Pleistocene based on post event deposition, cross-cutting relationships with Juan de Fuca Channel and the Willapa Channel levees and wave field, and post event slip on the frontal thrust of the Cascadia accretionary prism. The Holocene levees of both Willapa Channel and Juan de Fuca Channel overlap these older features, and clearly place an upper bound on the age of the erosional features in the latest Pleistocene. A lower bound is estimated from a sub-bottom profile that images ~30 meters of post scour sediment fill. Using existing literature of Holocene and Pleistocene sedimentation rates we estimate a lower age bound between ~23,000 - 56,000 y.b.p. We also map a fault scarp within the erosional feature, with ~60 m of vertical offset. Using multi-channel seismic reflection profiles from the COAST cruise we interpret this scarp as the surface expression of the landward vergent frontal thrust fault. The apparent short duration of the erosional event along the seaward margin of the accretionary wedge, coupled with the presence of the fresh fault scarp within the erosion zone, are indicative of a dormant

  15. Diffusion induced flow on a wedge-shaped obstacle

    NASA Astrophysics Data System (ADS)

    Zagumennyi, Ia V.; Dimitrieva, N. F.

    2016-08-01

    In this paper the problem of evolution of diffusion induced flow on a wedge-shaped obstacle is analyzed numerically. The governing set of fundamental equations is solved using original solvers from the open source OpenFOAM package on supercomputer facilities. Due to breaking of naturally existing diffusion flux of a stratifying agent by the impermeable surface of the wedge a complex multi-level vortex system of compensatory fluid motions is formed around the obstacle. Sharp edges of the obstacle generate extended high-gradient horizontal interfaces which are clearly observed in laboratory experiments by high-resolution Schlieren visualization. Formation of an intensive pressure depression zone in front of the leading vertex of the wedge is responsible for generation of propulsive force resulting in a self-displacement of the obstacle along the neutral buoyancy horizon in a stably stratified environment. The size of the pressure deficiency area near the sharp vertex of a concave wedge is about twice that for a convex one. This demonstrates a more intensive propulsion mechanism in case of the concave wedge and, accordingly, a higher velocity of its self-movement in a continuously stratified medium.

  16. On sound scattering by rigid edges and wedges in a flow, with applications to high-lift device aeroacoustics

    NASA Astrophysics Data System (ADS)

    Roger, Michel; Moreau, Stéphane; Kucukcoskun, Korcan

    2016-02-01

    Exact analytical solutions for the scattering of sound by the edge of a rigid half-plane and by a rigid corner in the presence of a uniform flow are considered in this work, for arbitrary source and observer locations. Exact Green's functions for the Helmholtz equation are first reviewed and implemented in a quiescent propagation space from reference expressions of the literature. The effect of uniform fluid motion is introduced in a second step and the properties of the field are discussed for point dipoles and quadrupoles. The asymptotic regime of a source close to the scattering edge/wedge and of an observer far from it in terms of acoustic wavelengths is derived in both cases. Its validity limits are assessed by comparing with the exact solutions. Typically the asymptotic directivity is imposed by Green's function but not by the source itself. This behaviour is associated with a strong enhancement of the radiation with respect to what the source would produce in free field. The amplification depends on the geometry, on the source type and on the source distance to the edge/wedge. Various applications in aeroacoustics of wall-bounded flows are addressed, more specifically dealing with high-lift device noise mechanisms, such as trailing-edge or flap side-edge noise. The asymptotic developments are used to highlight trends that are believed to play a role in airframe noise.

  17. CarD uses a minor groove wedge mechanism to stabilize the RNA polymerase open promoter complex.

    PubMed

    Bae, Brian; Chen, James; Davis, Elizabeth; Leon, Katherine; Darst, Seth A; Campbell, Elizabeth A

    2015-09-08

    A key point to regulate gene expression is at transcription initiation, and activators play a major role. CarD, an essential activator in Mycobacterium tuberculosis, is found in many bacteria, including Thermus species, but absent in Escherichia coli. To delineate the molecular mechanism of CarD, we determined crystal structures of Thermus transcription initiation complexes containing CarD. The structures show CarD interacts with the unique DNA topology presented by the upstream double-stranded/single-stranded DNA junction of the transcription bubble. We confirm that our structures correspond to functional activation complexes, and extend our understanding of the role of a conserved CarD Trp residue that serves as a minor groove wedge, preventing collapse of the transcription bubble to stabilize the transcription initiation complex. Unlike E. coli RNAP, many bacterial RNAPs form unstable promoter complexes, explaining the need for CarD.

  18. CarD uses a minor groove wedge mechanism to stabilize the RNA polymerase open promoter complex

    PubMed Central

    Bae, Brian; Chen, James; Davis, Elizabeth; Leon, Katherine; Darst, Seth A; Campbell, Elizabeth A

    2015-01-01

    A key point to regulate gene expression is at transcription initiation, and activators play a major role. CarD, an essential activator in Mycobacterium tuberculosis, is found in many bacteria, including Thermus species, but absent in Escherichia coli. To delineate the molecular mechanism of CarD, we determined crystal structures of Thermus transcription initiation complexes containing CarD. The structures show CarD interacts with the unique DNA topology presented by the upstream double-stranded/single-stranded DNA junction of the transcription bubble. We confirm that our structures correspond to functional activation complexes, and extend our understanding of the role of a conserved CarD Trp residue that serves as a minor groove wedge, preventing collapse of the transcription bubble to stabilize the transcription initiation complex. Unlike E. coli RNAP, many bacterial RNAPs form unstable promoter complexes, explaining the need for CarD. DOI: http://dx.doi.org/10.7554/eLife.08505.001 PMID:26349034

  19. Evaluation of a high-precision gear measuring machine for helix measurement using helix and wedge artifacts

    NASA Astrophysics Data System (ADS)

    Taguchi, Tetsuya; Kondo, Yohan

    2016-08-01

    High-precision gears are required for advanced motion and power transmission. The reliability of the measured value becomes important as the gear accuracy increases, and the establishment of a traceability system is needed. Therefore, a high-precision gear measuring machine (GMM) with a smaller uncertainty is expected to improve the gear calibration uncertainty. For this purpose, we developed a prototype of a high-precision GMM that adopts a direct drive mechanism and other features. Then, the high measurement capability of the developed GMM was verified using gear artifacts. Recently, some new measurement methods using simple shapes such as spheres and planes have been proposed as standards. We have verified the tooth profile measurement using a sphere artifact and reported the results that the developed GMM had a high capability in tooth profile measurement. Therefore, we attempted to devise a new evaluation method for helix measurement using a wedge artifact (WA) whose plane was treated as the tooth flank, and the high measurement capability of the developed GMM was verified. The results will provide a part of information to fully assess measurement uncertainty as our future work. This paper describes the evaluation results of the developed GMM for helix measurement using both a helix artifact and the WA, and discusses the effectiveness of the WA as a new artifact to evaluate the GMMs.

  20. Thermally actuated wedge block

    DOEpatents

    Queen, Jr., Charles C.

    1980-01-01

    This invention relates to an automatically-operating wedge block for maintaining intimate structural contact over wide temperature ranges, including cryogenic use. The wedging action depends on the relative thermal expansion of two materials having very different coefficients of thermal expansion. The wedge block expands in thickness when cooled to cryogenic temperatures and contracts in thickness when returned to room temperature.

  1. Wedge Joints for Trusses

    NASA Technical Reports Server (NTRS)

    Wood, Kenneth E.

    1987-01-01

    Structure assembled rapidly with simple hand tools. Proposed locking wedge joints enable rapid assembly of lightweight beams, towers, scaffolds, and other truss-type structures. Lightweight structure assembled from tubular struts joined at nodes by wedge pins fitting into mating slots. Joint assembled rapidly by seating wedge pin in V-shaped slots and deforming end of strut until primary pawl engages it.

  2. Structure of turbulent wedges created by isolated surface roughness

    NASA Astrophysics Data System (ADS)

    Kuester, Matthew S.; White, Edward B.

    2016-04-01

    Isolated surface roughness in a laminar boundary layer can create a wedge of turbulence that spreads laterally into the surrounding laminar flow. Some recent studies have identified high- and low-speed streaks along the exterior of turbulent wedges. In this experiment, developing turbulent wedges are measured to observe the creation of these streaks. Naphthalene shear stress surface visualization and hotwire measurements are utilized to investigate the details of turbulent wedges created by cylinders in a laminar flat-plate boundary layer. Both the surface visualization and the hotwire measurements show high- and low-speed streaks in the wake of the cylinder that devolve into a turbulent wedge. The turbulent wedge spreading is associated with the emergence of these high- and low-speed streaks along the outside of the wedge. As the wedge evolves in the streamwise direction, these streaks persist inside of the core of the wedge, while new, lower amplitude streaks form along the outside of the wedge. Adding asymmetry to the cylinder moved the virtual origin closer to the roughness and increased the vortex shedding frequency, while adding small-scale roughness features did not strongly affect turbulent wedge development. Intermittency calculations additionally show the origin of the turbulent core inside of the wedge. The structure and spacing of the high-speed streaks along the extremities of the turbulent wedge give insight into the spreading angle of the turbulent wedge.

  3. The matching of wedge transmission factors across six multi-energy linear accelerators.

    PubMed

    Weston, S J; Thompson, R C A; Morgan, A M

    2007-01-01

    Elekta Precise linear accelerators create a wedged isodose distribution using a single, fixed, motorized wedge with a nominal wedge angle of 60 degrees. Wedge angles of less than 60 degrees can be produced by varying the proportion of open and wedge monitor units for a given exposure. The fixed wedge can be replaced with a mobile wedge, the position of which can be moved in order to adjust the wedge transmission factor (WTF). Using the original fixed wedges installed in our fleet of six Elekta accelerators, we found a range of 4% in measured wedge transmission factor for 6 MV beams. Results are presented which demonstrate that by using the mobile wedge it is possible to match the wedge transmission factors to within 1% for the six linear accelerators over three energies. PMID:17267473

  4. Wedged Fibers Suppress Feedback of Laser Beam

    NASA Technical Reports Server (NTRS)

    Ladany, I.

    1986-01-01

    When injected laser is coupled into optical fiber, emission instabilities arise because of optical feedback losses from fiber into laser. Coupling efficiencies as high as 80 percent, however, obtained by shaping end of multimode fiber into obtuse-angled wedge. Because slanted sides eliminate back reflection, such wedged fiber achieves high coupling efficiency.

  5. Five questions to consider before conducting a stepped wedge trial.

    PubMed

    Hargreaves, James R; Copas, Andrew J; Beard, Emma; Osrin, David; Lewis, James J; Davey, Calum; Thompson, Jennifer A; Baio, Gianluca; Fielding, Katherine L; Prost, Audrey

    2015-08-17

    Researchers should consider five questions before starting a stepped wedge trial. Why are you planning one? Researchers sometimes think that stepped wedge trials are useful when there is little doubt about the benefit of the intervention being tested. However, if the primary reason for an intervention is to measure its effect, without equipoise there is no ethical justification for delaying implementation in some clusters. By contrast, if you are undertaking pragmatic research, where the primary reason for rolling out the intervention is for it to exert its benefits, and if phased implementation is inevitable, a stepped wedge trial is a valid option and provides better evidence than most non-randomized evaluations. What design will you use? Two common stepped wedge designs are based on the recruitment of a closed or open cohort. In both, individuals may experience both control and intervention conditions and you should be concerned about carry-over effects. In a third, continuous-recruitment, short-exposure design, individuals are recruited as they become eligible and experience either control or intervention condition, but not both. How will you conduct the primary analysis? In stepped wedge trials, control of confounding factors through secular variation is essential. 'Vertical' approaches preserve randomization and compare outcomes between randomized groups within periods. 'Horizontal' approaches compare outcomes before and after crossover to the intervention condition. Most analysis models used in practice combine both types of comparison. The appropriate analytic strategy should be considered on a case-by-case basis. How large will your trial be? Standard sample size calculations for cluster randomized trials do not accommodate the specific features of stepped wedge trials. Methods exist for many stepped wedge designs, but simulation-based calculations provide the greatest flexibility. In some scenarios, such as when the intracluster correlation coefficient is

  6. Coupled wedge waves.

    PubMed

    Abell, Bradley C; Pyrak-Nolte, Laura J

    2013-11-01

    The interface between two wedges can be treated as a displacement discontinuity characterized by elastic stiffnesses. By representing the boundary between the two quarter-spaces as a displacement discontinuity, coupled wedge waves were determined theoretically to be dispersive and to depend on the specific stiffness of the non-welded contact between the two wedges. Laboratory experiments on isotropic and anisotropic aluminum confirmed the theoretical prediction that the velocity of coupled wedge waves, for a non-welded interface, ranged continuously from the single wedge wave velocity at low stress to the Rayleigh velocity as the load applied normal to the interface was increased. Elastic waves propagating along the coupled wedges of two quarter-spaces in non-welded contact are found to exist theoretically even when the material properties of the two quarter-spaces are the same.

  7. Bacterial diversity across a highly stratified ecosystem: A salt-wedge Mediterranean estuary.

    PubMed

    Korlević, M; Šupraha, L; Ljubešić, Z; Henderiks, J; Ciglenečki, I; Dautović, J; Orlić, S

    2016-09-01

    Highly stratified Mediterranean estuaries are unique environments where the tidal range is low and the tidal currents are almost negligible. The main characteristics of these environments are strong salinity gradients and other environmental parameters. In this study, 454 pyrosequencing of the 16S rRNA gene in combination with catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) was used to estimate the bacterial diversity across the Krka estuary in February and July 2013. The comparison of the data derived from these two techniques resulted in a significant but weak positive correlation (R=0.28) indicating a substantial difference in the bacterial community structure, depending on the applied method. The phytoplankton bloom observed in February was identified as one of the main factors shaping the bacterial community structure between the two environmentally contrasting sampling months. Roseobacter, Bacteroidetes and Gammaproteobacteria differed substantially between February and July. Typical freshwater bacterial classes (Actinobacteria and Betaproteobacteria) showed strong vertical distribution patterns depending on the salinity gradient. Cyanobacteria decreased in abundance in February due to competition with phytoplankton, while the SAR11 clade increased its abundance in July as a result of a better adaptation toward more oligotrophic conditions. The results provided the first detailed insight into the bacterial diversity in a highly stratified Mediterranean karstic estuary. PMID:27475818

  8. Ice Particle Impacts on a Moving Wedge

    NASA Technical Reports Server (NTRS)

    Vargas, Mario; Struk, Peter M.; Kreeger, Richard E.; Palacios, Jose; Iyer, Kaushik A.; Gold, Robert E.

    2014-01-01

    This work presents the results of an experimental study of ice particle impacts on a moving wedge. The experiment was conducted in the Adverse Environment Rotor Test Stand (AERTS) facility located at Penn State University. The wedge was placed at the tip of a rotating blade. Ice particles shot from a pressure gun intercepted the moving wedge and impacted it at a location along its circular path. The upward velocity of the ice particles varied from 7 to 12 meters per second. Wedge velocities were varied from 0 to 120 meters per second. Wedge angles tested were 0 deg, 30 deg, 45 deg, and 60 deg. High speed imaging combined with backlighting captured the impact allowing observation of the effect of velocity and wedge angle on the impact and the post-impact fragment behavior. It was found that the pressure gun and the rotating wedge could be synchronized to consistently obtain ice particle impacts on the target wedge. It was observed that the number of fragments increase with the normal component of the impact velocity. Particle fragments ejected immediately after impact showed velocities higher than the impact velocity. The results followed the major qualitative features observed by other researchers for hailstone impacts, even though the reduced scale size of the particles used in the present experiment as compared to hailstones was 4:1.

  9. Ice Particle Impacts on a Moving Wedge

    NASA Technical Reports Server (NTRS)

    Vargas, Mario; Struk, Peter M.; Kreeger, Richard E.; Palacios, Jose; Lyer, Kaushik A.; Gold, Robert E.

    2014-01-01

    This work presents the results of an experimental study of ice particle impacts on a moving wedge. The experiment was conducted in the Adverse Environment Rotor Test Stand (AERTS) facility located at Penn State University. The wedge was placed at the tip of a rotating blade. Ice particles shot from a pressure gun intercepted the moving wedge and impacted it at a location along its circular path. The upward velocity of the ice particles varied from 7 to 12 meters per second. Wedge velocities were varied from 0 to 120 meters per second. Wedge angles tested were 0, 30, 45, and 60. High speed imaging combined with backlighting captured the impact allowing observation of the effect of velocity and wedge angle on the impact and the post-impact fragment behavior. It was found that the pressure gun and the rotating wedge could be synchronized to consistently obtain ice particle impacts on the target wedge. It was observed that the number of fragments increase with the normal component of the impact velocity. Particle fragments ejected immediately after impact showed velocities higher than the impact velocity. The results followed the major qualitative features observed by other researchers for hailstone impacts, even though the reduced scale size of the particles used in the present experiment as compared to hailstones was 4:1.

  10. Sojourner, Wedge, & Shark

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This Imager for Mars Pathfinder (IMP) image taken near the end of daytime operations on Sol 50 shows the Sojourner rover between the rocks 'Wedge' (foreground) and 'Shark' (behind rover). The rover successfully deployed its Alpha Proton X-Ray Spectrometer on Shark on Sol 52.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  11. Micromachine Wedge Stepping Motor

    SciTech Connect

    Allen, J.J.; Schriner, H.K.

    1998-11-04

    A wedge stepping motor, which will index a mechanism, has been designed and fabricated in the surface rnicromachine SUMMiT process. This device has demonstrated the ability to index one gear tooth at a time with speeds up to 205 teeth/see. The wedge stepper motor has the following features, whi:h will be useful in a number of applications. o The ability to precisely position mechanical components. . Simple pulse signals can be used for operation. o Only 2 drive signals are requixed for operation. o Torque and precision capabilities increase with device size . The device to be indexed is restrained at all times by the wedge shaped tooth that is used for actuation. This paper will discuss the theory of operation and desi=m of the wedge stepping motor. The fabrication and testing of I he device will also be presented.

  12. Wedges for ultrasonic inspection

    DOEpatents

    Gavin, Donald A.

    1982-01-01

    An ultrasonic transducer device is provided which is used in ultrasonic inspection of the material surrounding a threaded hole and which comprises a wedge of plastic or the like including a curved threaded surface adapted to be screwed into the threaded hole and a generally planar surface on which a conventional ultrasonic transducer is mounted. The plastic wedge can be rotated within the threaded hole to inspect for flaws in the material surrounding the threaded hole.

  13. Ultrasonic transducer with laminated coupling wedge

    DOEpatents

    Karplus, Henry H. B.

    1976-08-03

    An ultrasonic transducer capable of use in a high-temperature environment incorporates a laminated metal coupling wedge including a reflecting edge shaped as a double sloping roof and a transducer crystal backed by a laminated metal sound absorber disposed so as to direct sound waves through the coupling wedge and into a work piece, reflections from the interface between the coupling wedge and the work piece passing to the reflecting edge. Preferably the angle of inclination of the two halves of the reflecting edge are different.

  14. The Cosmonaut Sea Wedge

    USGS Publications Warehouse

    Solli, K.; Kuvaas, B.; Kristoffersen, Y.; Leitchenkov, G.; Guseva, J.; Gandyukhin, V.

    2007-01-01

    A set of multi-channel seismic profiles (~15000 km) acquired by Russia, Norway and Australia has been used to investigate the depositional evolution of the Cosmonaut Sea margin of East Antarctica. We recognize a regional sediment wedge below the upper part of the continental rise. The wedge, herein termed the Cosmonaut Sea Wedge, is positioned stratigraphically underneath the inferred glaciomarine section and extends for at least 1200 km along the continental margin and from 80 to about 250 km seaward or to the north. Lateral variations in the growth pattern of the wedge indicate several overlapping depocentres, which at their distal northern end are flanked by elongated mounded drifts and contourite sheets. The internal stratification of the mounded drift deposits suggests that westward flowing bottom currents reworked the marginal deposits. The action of these currents together with sea-level changes is considered to have controlled the growth of the wedge. We interpret the Cosmonaut Sea Wedge as a composite feature comprising several bottom current reworked fan systems.

  15. Wedge and Flat Top

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Flat Top, the rectangular rock at right, is part of a stretch of rocky terrain in this image, taken by the deployed Imager for Mars Pathfinder (IMP) on Sol 3. Dust has accumulated on the top of Flat Top, but is not present on the sides due to the steep angles of the rock. This dust may have been placed by dust storms moving across the Martian surface. The rock dubbed 'Wedge' is at left. The objects have been studied using several different color filters on the IMP camera.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  16. Single-stage closing-opening wedge osteotomy of spine to correct severe post-tubercular kyphotic deformities of the spine: a 3-year follow-up of 17 patients.

    PubMed

    Rajasekaran, S; Vijay, Kamath; Shetty, Ajoy Prasad

    2010-04-01

    The correction of severe post-tubercular kyphosis (PTK) is complex and has the disadvantage of being multiple staged with a high morbidity. Here, we describe the procedure and results of closing-opening osteotomy for correction of PTK which shortens the posterior column and opens the anterior column appropriately to correct the deformity without altering the length of the spinal cord. Seventeen patients with PTK (10 males; 7 females) with an average age of 18.3 +/- 10.6 years (range 4-40 years) formed the study group. There were ten thoracolumbar, one lumbar and six thoracic deformities. The number of vertebrae involved ranged from 2 to 5 (average 2.8). Preoperative kyphosis averaged 69.2 degrees +/- 25.1 degrees (range 42 degrees -104 degrees ) which included ten patients with deformity greater than 60 degrees . The average vertebral body loss was 2.01 +/- 0.79 (range 1.1-4.1). The neurological status was normal in 13 patients, Frankel's grade D in three patients and grade C in one. Posterior stabilization with pedicle screw instrumentation was followed by a preoperatively calculated wedge resection. Anterior column reconstruction was performed using rib grafts in four, tricortical iliac bone graft in five, cages in six, and bone chips alone and fibular graft in one patient each. Average operating time was 280 min (200-340 min) with an average blood loss of 820 ml (range 500-1,600 ml). The postoperative kyphosis averaged 32.4 degrees +/- 19.5 degrees (range 8 degrees -62 degrees ). The percentage correction of kyphosis achieved was 56.8 +/- 14.6% (range 32-83%). No patient with normal preoperative neurological status showed deterioration in neurology after surgery. The last follow-up was at an average of 43 +/- 4 months (range 32-64 months). The average loss of correction at the last follow-up was 5.4 degrees (range 3 degrees -9 degrees ). At the last follow-up, the mean preoperative pain visual analogue scale score decreased significantly from 9.2 (range 8

  17. Long polymers near wedges and cones

    NASA Astrophysics Data System (ADS)

    Hammer, Yosi; Kantor, Yacov

    2015-12-01

    We perform a Monte Carlo study of N -step self-avoiding walks, attached to the corner of an impenetrable wedge in two dimensions (d =2 ), or the tip of an impenetrable cone in d =3 , of sizes ranging up to N =106 steps. We find that the critical exponent γα, which determines the dependence of the number of available conformations on N for a cone or wedge with opening angle α , is in good agreement with the theory for d =2 . We study the end-point distribution of the walks in the allowed space and find similarities to the known behavior of random walks (ideal polymers) in the same geometry. For example, the ratio between the mean square end-to-end distances of a polymer near the cone or wedge and a polymer in free space depends linearly on γα, as is known for ideal polymers. We show that the end-point distribution of polymers attached to a wedge does not separate into a product of angular and radial functions, as it does for ideal polymers in the same geometry. The angular dependence of the end position of polymers near the wedge differs from theoretical predictions.

  18. Long polymers near wedges and cones.

    PubMed

    Hammer, Yosi; Kantor, Yacov

    2015-12-01

    We perform a Monte Carlo study of N-step self-avoiding walks, attached to the corner of an impenetrable wedge in two dimensions (d=2), or the tip of an impenetrable cone in d=3, of sizes ranging up to N=10(6) steps. We find that the critical exponent γ(α), which determines the dependence of the number of available conformations on N for a cone or wedge with opening angle α, is in good agreement with the theory for d=2. We study the end-point distribution of the walks in the allowed space and find similarities to the known behavior of random walks (ideal polymers) in the same geometry. For example, the ratio between the mean square end-to-end distances of a polymer near the cone or wedge and a polymer in free space depends linearly on γ(α), as is known for ideal polymers. We show that the end-point distribution of polymers attached to a wedge does not separate into a product of angular and radial functions, as it does for ideal polymers in the same geometry. The angular dependence of the end position of polymers near the wedge differs from theoretical predictions. PMID:26764719

  19. Europa Wedge Region

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This image shows an area of crustal separation on Jupiter's moon, Europa. Lower resolution pictures taken earlier in the tour of NASA's Galileo spacecraft revealed that dark wedge-shaped bands in this region are areas where the icy crust has completely pulled apart. Dark material has filled up from below and filled the void created by this separation.

    In the lower left corner of this image, taken by Galileo's onboard camera on December 16, 1997, a portion of one dark wedge area is visible, revealing a linear texture along the trend of the wedge. The lines of the texture change orientation slightly and reflect the fact that we are looking at a bend in the wedge. The older, bright background, visible on the right half of the image, is criss-crossed with ridges. A large, bright ridge runs east-west through the upper part of the image, cutting across both the older background plains and the wedge. This ridge is rough in texture, with numerous small terraces and troughs containing dark material.

    North is to the top of the picture and the sun illuminates the surface from the northwest. This image, centered at approximately 16.5 degrees south latitude and 196.5 degrees west longitude, covers an area approximately 10 kilometers square (about 6.5 miles square). The resolution of this image is about 26 meters per picture element. This image was taken by the solid state imaging system from a distance of 1250 kilometers (750 miles).

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  20. Transmural Ultrasound Imaging of Thermal Lesion and Action Potential Changes in Perfused Canine Cardiac Wedge Preparations by High Intensity Focused Ultrasound Ablation

    PubMed Central

    Wu, Ziqi; Gudur, Madhu S. R.; Deng, Cheri X.

    2013-01-01

    Intra-procedural imaging is important for guiding cardiac arrhythmia ablation. It is difficult to obtain intra-procedural correlation of thermal lesion formation with action potential (AP) changes in the transmural plane during ablation. This study tested parametric ultrasound imaging for transmural imaging of lesion and AP changes in high intensity focused ultrasound (HIFU) ablation using coronary perfused canine ventricular wedge preparations (n = 13). The preparations were paced from epi/endocardial surfaces and subjected to HIFU application (3.5 MHz, 11 Hz pulse-repetition-frequency, 70% duty cycle, duration 4 s, 3500 W/cm2), during which simultaneous optical mapping (1 kframes/s) using di-4-ANEPPS and ultrasound imaging (30 MHz) of the same transmural surface of the wedge were performed. Spatiotemporally correlated AP measurements and ultrasound imaging allowed quantification of the reduction of AP amplitude (APA), shortening of AP duration at 50% repolarization, AP triangulation, decrease of optical AP rise, and change of conduction velocity along tissue depth direction within and surrounding HIFU lesions. The threshold of irreversible change in APA correlating to lesions was determined to be 43±1% with a receiver operating characteristic (ROC) area under curve (AUC) of 0.96±0.01 (n = 13). Ultrasound imaging parameters such as integrated backscatter, Rayleigh (α) and log-normal (σ) parameters, cumulative extrema of σ were tested, with the cumulative extrema of σ performing the best in detecting lesion (ROC AUC 0.89±0.01, n = 13) and change of APA (ROC AUC 0.79±0.03, n = 13). In conclusion, characteristic tissue and AP changes in HIFU ablation were identified and spatiotemporally correlated using optical mapping and ultrasound imaging. Parametric ultrasound imaging using cumulative extrema of σ can detect HIFU lesion and APA reduction. PMID:24349337

  1. Mechanics of injection wedges in collision orogens

    NASA Astrophysics Data System (ADS)

    Thompson, A. B.; Schulmann, K.

    2003-04-01

    Instantaneously juxtaposed lithospheric sections, marked by different geothermal gradient and lithological make-up, are examined to identify zones of highly contrasting strength in adjacent transposed crust and lithospheric mantle. Three types of geotherms and four reference lithospheric segments: thin crust/hot geotherm (rift), thin crust/mean geotherm (relaxed rift), standard crust/hot geotherm (arc), standard crust/mean geotherm (normal crust), are compared with variable permutations of cratonic, standard and rifted lithosphere thicknesses. This permits identification of strong brittle-elastic or plastic mantle, lower and upper crust juxtaposed against plastic rocks of a weak adjacent lithosphere. Vertical positions of shallow dipping detachment zones thus delineate possible areas of hot or cold injection wedges which include: (i) Single shallow wedge (or Flake), (ii) Double shallow and deep wedge, (iii) Deep lithospheric crocodile, (iv) Crustal thickening due to shallow strength differences, (v) Mantle Lithosphere thickening, or wedging, due to deep mantle strength differences and (vii) Exchange tectonics as an extreme wedging process, in which horizontal mass exchange is approximately equal. Rheological calculations are compared to a database of seismic profiles in which the geometry of detachment zones and proposed thermal conditions and lithological make-ups have been presented.

  2. Microtopographic characterization of ice-wedge polygon landscape in Barrow, Alaska: a digital map of troughs, rims, centers derived from high resolution (0.25 m) LiDAR data

    SciTech Connect

    Gangodagamage, Chandana; Wullschleger, Stan

    2014-07-03

    The dataset represents microtopographic characterization of the ice-wedge polygon landscape in Barrow, Alaska. Three microtopographic features are delineated using 0.25 m high resolution digital elevation dataset derived from LiDAR. The troughs, rims, and centers are the three categories in this classification scheme. The polygon troughs are the surface expression of the ice-wedges that are in lower elevations than the interior polygon. The elevated shoulders of the polygon interior immediately adjacent to the polygon troughs are the polygon rims for the low center polygons. In case of high center polygons, these features are the topographic highs. In this classification scheme, both topographic highs and rims are considered as polygon rims. The next version of the dataset will include more refined classification scheme including separate classes for rims ad topographic highs. The interior part of the polygon just adjacent to the polygon rims are the polygon centers.

  3. Capillary Rise in a Wedge

    ERIC Educational Resources Information Center

    Piva, M.

    2009-01-01

    In introductory-level physics courses, the concept of surface tension is often illustrated using the example of capillary rise in thin tubes. In this paper the author describes experiments conducted using a planar geometry created with two small plates forming a thin wedge. The distribution of the fluid entering the wedge can be studied as a…

  4. Life at the wedge: the activity and diversity of arctic ice wedge microbial communities.

    PubMed

    Wilhelm, Roland C; Radtke, Kristin J; Mykytczuk, Nadia C S; Greer, Charles W; Whyte, Lyle G

    2012-04-01

    The discovery of polygonal terrain on Mars underlain by ice heightens interest in the possibility that this water-bearing habitat may be, or may have been, a suitable habitat for extant life. The possibility is supported by the recurring detection of terrestrial microorganisms in subsurface ice environments, such as ice wedges found beneath tundra polygon features. A characterization of the microbial community of ice wedges from the high Arctic was performed to determine whether this ice environment can sustain actively respiring microorganisms and to assess the ecology of this extreme niche. We found that ice wedge samples contained a relatively abundant number of culturable cells compared to other ice habitats (∼10(5) CFU·mL(-1)). Respiration assays in which radio-labeled acetate and in situ measurement of CO(2) flux were used suggested low levels of microbial activity, though more sensitive techniques are required to confirm these findings. Based on 16S rRNA gene pyrosequencing, bacterial and archaeal ice wedge communities appeared to reflect surrounding soil communities. Two Pseudomonas sp. were the most abundant taxa in the ice wedge bacterial library (∼50%), while taxa related to ammonia-oxidizing Thaumarchaeota occupied 90% of the archaeal library. The tolerance of a variety of isolates to salinity and temperature revealed characteristics of a psychrotolerant, halotolerant community. Our findings support the hypothesis that ice wedges are capable of sustaining a diverse, plausibly active microbial community. As such, ice wedges, compared to other forms of less habitable ground ice, could serve as a reservoir for life on permanently cold, water-scarce, ice-rich extraterrestrial bodies and are therefore of interest to astrobiologists and ecologists alike. .

  5. Life at the wedge: the activity and diversity of arctic ice wedge microbial communities.

    PubMed

    Wilhelm, Roland C; Radtke, Kristin J; Mykytczuk, Nadia C S; Greer, Charles W; Whyte, Lyle G

    2012-04-01

    The discovery of polygonal terrain on Mars underlain by ice heightens interest in the possibility that this water-bearing habitat may be, or may have been, a suitable habitat for extant life. The possibility is supported by the recurring detection of terrestrial microorganisms in subsurface ice environments, such as ice wedges found beneath tundra polygon features. A characterization of the microbial community of ice wedges from the high Arctic was performed to determine whether this ice environment can sustain actively respiring microorganisms and to assess the ecology of this extreme niche. We found that ice wedge samples contained a relatively abundant number of culturable cells compared to other ice habitats (∼10(5) CFU·mL(-1)). Respiration assays in which radio-labeled acetate and in situ measurement of CO(2) flux were used suggested low levels of microbial activity, though more sensitive techniques are required to confirm these findings. Based on 16S rRNA gene pyrosequencing, bacterial and archaeal ice wedge communities appeared to reflect surrounding soil communities. Two Pseudomonas sp. were the most abundant taxa in the ice wedge bacterial library (∼50%), while taxa related to ammonia-oxidizing Thaumarchaeota occupied 90% of the archaeal library. The tolerance of a variety of isolates to salinity and temperature revealed characteristics of a psychrotolerant, halotolerant community. Our findings support the hypothesis that ice wedges are capable of sustaining a diverse, plausibly active microbial community. As such, ice wedges, compared to other forms of less habitable ground ice, could serve as a reservoir for life on permanently cold, water-scarce, ice-rich extraterrestrial bodies and are therefore of interest to astrobiologists and ecologists alike. . PMID:22519974

  6. Wedge Waveguides and Resonators for Quantum Plasmonics

    PubMed Central

    2015-01-01

    Plasmonic structures can provide deep-subwavelength electromagnetic fields that are useful for enhancing light–matter interactions. However, because these localized modes are also dissipative, structures that offer the best compromise between field confinement and loss have been sought. Metallic wedge waveguides were initially identified as an ideal candidate but have been largely abandoned because to date their experimental performance has been limited. We combine state-of-the-art metallic wedges with integrated reflectors and precisely placed colloidal quantum dots (down to the single-emitter level) and demonstrate quantum-plasmonic waveguides and resonators with performance approaching theoretical limits. By exploiting a nearly 10-fold improvement in wedge-plasmon propagation (19 μm at a vacuum wavelength, λvac, of 630 nm), efficient reflectors (93%), and effective coupling (estimated to be >70%) to highly emissive (∼90%) quantum dots, we obtain Ag plasmonic resonators at visible wavelengths with quality factors approaching 200 (3.3 nm line widths). As our structures offer modal volumes down to ∼0.004λvac3 in an exposed single-mode waveguide–resonator geometry, they provide advantages over both traditional photonic microcavities and localized-plasmonic resonators for enhancing light–matter interactions. Our results confirm the promise of wedges for creating plasmonic devices and for studying coherent quantum-plasmonic effects such as long-distance plasmon-mediated entanglement and strong plasmon–matter coupling. PMID:26284499

  7. Wedge Waveguides and Resonators for Quantum Plasmonics.

    PubMed

    Kress, Stephan J P; Antolinez, Felipe V; Richner, Patrizia; Jayanti, Sriharsha V; Kim, David K; Prins, Ferry; Riedinger, Andreas; Fischer, Maximilian P C; Meyer, Stefan; McPeak, Kevin M; Poulikakos, Dimos; Norris, David J

    2015-09-01

    Plasmonic structures can provide deep-subwavelength electromagnetic fields that are useful for enhancing light-matter interactions. However, because these localized modes are also dissipative, structures that offer the best compromise between field confinement and loss have been sought. Metallic wedge waveguides were initially identified as an ideal candidate but have been largely abandoned because to date their experimental performance has been limited. We combine state-of-the-art metallic wedges with integrated reflectors and precisely placed colloidal quantum dots (down to the single-emitter level) and demonstrate quantum-plasmonic waveguides and resonators with performance approaching theoretical limits. By exploiting a nearly 10-fold improvement in wedge-plasmon propagation (19 μm at a vacuum wavelength, λvac, of 630 nm), efficient reflectors (93%), and effective coupling (estimated to be >70%) to highly emissive (~90%) quantum dots, we obtain Ag plasmonic resonators at visible wavelengths with quality factors approaching 200 (3.3 nm line widths). As our structures offer modal volumes down to ~0.004λvac(3) in an exposed single-mode waveguide-resonator geometry, they provide advantages over both traditional photonic microcavities and localized-plasmonic resonators for enhancing light-matter interactions. Our results confirm the promise of wedges for creating plasmonic devices and for studying coherent quantum-plasmonic effects such as long-distance plasmon-mediated entanglement and strong plasmon-matter coupling.

  8. Medial Closing-Wedge Distal Femoral Osteotomy: Fixation With Proximal Tibial Locking Plate

    PubMed Central

    Tírico, Luís Eduardo Passarelli; Demange, Marco Kawamura; Bonadio, Marcelo Batista; Helito, Camilo Partezani; Gobbi, Riccardo Gomes; Pécora, José Ricardo

    2015-01-01

    Distal femoral varus osteotomy is a well-established procedure for the treatment of lateral compartment cartilage lesions and degenerative disease, correcting limb alignment and decreasing the progression of the pathology. Surgical techniques can be performed with a lateral opening-wedge or medial closing-wedge correction of the deformity. Fixation methods for lateral opening-wedge osteotomies are widely available, and there are various types of implants that can be used for fixation. However, there are currently only a few options of implants for fixation of a medial closing-wedge osteotomy on the market. This report describes a medial, supracondylar, V-shaped, closing-wedge distal femoral osteotomy using a locked anterolateral proximal tibial locking plate that fits anatomically to the medial side of the distal femur. This is a great option as a stable implant for a medial closing-wedge distal femoral osteotomy. PMID:26870647

  9. Two dimensional wedge/translating shroud nozzle

    NASA Technical Reports Server (NTRS)

    Maiden, D. L. (Inventor)

    1978-01-01

    A jet propulsion exhaust nozzle is reported for multi-engine installations which produces high internal/external, thrust-minus-drag, performance for transonic cruise or transonic acceleration as well as improved performance at subsonic and supersonic speeds. A two dimensional wedge/translating shroud provides the variable nozzle exit geometry needed to achieve high engine performance over a wide range of throttle power settings.

  10. Ancient Yedoma carbon loss: primed by ice wedge thaw?

    NASA Astrophysics Data System (ADS)

    Dowdy, K. L.; Vonk, J. E.; Mann, P. J.; Zimov, N.; Bulygina, E. B.; Davydova, A.; Spencer, R. G.; Holmes, R. M.

    2012-12-01

    Northeast Siberian permafrost is dominated by frozen Yedoma deposits containing ca. 500 Gt of carbon, nearly a quarter of northern permafrost organic carbon (OC). Yedoma deposits are Pleistocene-age alluvial and/or aeolian accumulations characterized by high ice wedge content (~50%), making them particularly vulnerable to a warming climate and to surface collapse upon thaw. Dissolved OC in streams originating primarily from Yedoma has been shown to be highly biolabile, relative to waters containing more modern OC. The cause of this biolability, however, remains speculative. Here we investigate the influence of ice wedge input upon the bioavailability of Yedoma within streams from as a potential cause of Yedoma carbon biolability upon release into the Kolyma River from the thaw-eroding river exposures of Duvannyi Yar, NE Siberia. We measured biolability on (1) ice wedge, Kolyma, and Yedoma leachate controls; (2) ice wedge and Kolyma plus Yedoma OC (8 g/L); and (3) varying ratios of ice wedge water to Kolyma river water. Biolability assays were conducted using both 5-day BOD (biological oxygen demand) and 11-day BDOC (biodegradable dissolved organic carbon) incubations. We found that ancient DOC in Yedoma soil leachate alone was highly biolabile with losses of 52±0.1% C over a 5-day BOD incubation. Similarly, DOC contained in pure ice wedge water was found to be biolabile, losing 21±0% C during a 5-day BOD incubation. Increased ice wedge contributions led to higher overall C losses in identical Yedoma soil leachates, with 8.9±0.6% losses of Yedoma C with 100% ice wedge water, 7.1±1% (50% ice wedge/ 50% Kolyma) and 5±0.3% with 100% Kolyma River water. We discuss potential mechanisms for the increased loss of ancient C using associated measurements of nutrient availability, carbon quality (CDOM/FDOM) and extracellular enzyme activity rates. Our initial results indicate that ice wedge meltwater forming Yedoma streams makes Yedoma OC more bioavailable than it would

  11. Effect of Mantle Wedge Hybridization by Sediment Melt on Geochemistry of Arc Magma and Arc Mantle Source - Insights from Laboratory Experiments at High Pressures and Temperatures

    NASA Astrophysics Data System (ADS)

    Mallik, A.; Dasgupta, R.; Tsuno, K.; Nelson, J. M.

    2015-12-01

    Generation of arc magmas involves metasomatism of the mantle wedge by slab-derived H2O-rich fluids and/or melts and subsequent melting of the modified source. The chemistry of arc magmas and the residual mantle wedge are not only regulated by the chemistry of the slab input, but also by the phase relations of metasomatism or hybridization process in the wedge. The sediment-derived silica-rich fluids and hydrous partial melts create orthopyroxene-rich zones in the mantle wedge, due to reaction of mantle olivine with silica in the fluid/melt [1,2]. Geochemical evidence for such a reaction comes from pyroxenitic lithologies coexisting with peridotite in supra-subduction zones. In this study, we have simulated the partial melting of a parcel of mantle wedge modified by bulk addition of sediment-derived melt with variable H2O contents to investigate the major and trace element chemistry of the magmas and the residues formed by this process. Experiments at 2-3 GPa and 1150-1300 °C were conducted on mixtures of 25% sediment-derived melt and 75% lherzolite, with bulk H2O contents varying from 2 to 6 wt.%. Partial reactive crystallization of the rhyolitic slab-derived melt and partial melting of the mixed source produced a range of melt compositions from ultra-K basanites to basaltic andesites, in equilibrium with an orthopyroxene ± phlogopite ± clinopyroxene ± garnet bearing residue, depending on P and bulk H2O content. Model calculations using partition coefficients (from literature) of trace elements between experimental minerals and silicate melt suggest that the geochemical signatures of the slab-derived melt, such as low Ce/Pb and depletion in Nb and Ta (characteristic slab signatures) are not erased from the resulting melt owing to reactive crystallization. The residual mineral assemblage is also found to be similar to the supra-subduction zone lithologies, such as those found in Dabie Shan (China) and Sanbagawa Belt (Japan). In this presentation, we will also

  12. Deformation of the Calabrian accretionary wedge and relative kinematics of the Calabrian and Peloritan backstops: Insights from multibeam bathymetry, high-resolution reflection and wide-angle seismics and analog modeling

    NASA Astrophysics Data System (ADS)

    Dellong, David; Gutscher, Marc-Andre; Klingelhoefer, Frauke; Graindorge, David; Kopp, Heidrun; Moretti, Milena; Marsset, Bruno; Mercier de Lepinay, Bernard; Dominguez, Stephane; Malavieille, Jacques

    2016-04-01

    Recently acquired swath bathymetric data in the Ionian Sea document in unprecedented detail the morphostructure and dynamics of the Calabrian accretionary wedge. A boundary zone between the eastern and western lobes of the accretionary wedge is examined here. Relative displacement between the Calabrian and Peloritan backstops is expected to cause dextral strike-slip deformation between the lobes. A wide-angle seismic profile was acquired in Oct. 2014 with the R/V Meteor (DIONYSUS survey) recorded by 25 Ocean-bottom seismometers (Geomar and Ifremer instruments) and 3 land-stations (INGV stations). Inversion and forward modeling of these seismic data reveal a 5-10 km deep asymmetric rift zone between the Malta Escarpment and the SW tip of Calabria. Analog modeling was performed to test if the origin of this rift could be related to the relative kinematics of the Calabrian and Peloritan backstops. Modeling, using two independently moving backstops, produces a zone of dextral transtension and subsidence in the accretionary wedge between two lobes. This corresponds well to the asymmetric rift observed in the southward prolongation of the straits of Messina faults. Paradoxically however, this dextral displacement does not appear to traverse the external Calabrian accretionary wedge, where prominent curved lineaments observed indicate a sinistral sense of motion. One possible explanation is that the dextral kinematic motion is transferred into a region of crisscrossing faults in the internal portion of the Eastern lobe. The bathymetry and high-resolution reflection seismic images indicate ongoing compression at the deformation front of both the western and eastern lobes. Together with the analog modeling results, these observations unambiguously demonstrate that the western lobe remains tectonically active.

  13. Dosimetric Characteristics of 6 MV Modified Beams by Physical Wedges of a Siemens Linear Accelerator.

    PubMed

    Zabihzadeh, Mansour; Birgani, Mohammad Javad Tahmasebi; Hoseini-Ghahfarokhi, Mojtaba; Arvandi, Sholeh; Hoseini, Seyed Mohammad; Fadaei, Mahbube

    2016-01-01

    Physical wedges still can be used as missing tissue compensators or filters to alter the shape of isodose curves in a target volume to reach an optimal radiotherapy plan without creating a hotspot. The aim of this study was to investigate the dosimetric properties of physical wedges filters such as off-axis photon fluence, photon spectrum, output factor and half value layer. The photon beam quality of a 6 MV Primus Siemens modified by 150 and 450 physical wedges was studied with BEAMnrc Monte Carlo (MC) code. The calculated present depth dose and dose profile curves for open and wedged photon beam were in good agreement with the measurements. Increase of wedge angle increased the beam hardening and this effect was more pronounced at the heal region. Using such an accurate MC model to determine of wedge factors and implementation of it as a calculation algorithm in the future treatment planning systems is recommended. PMID:27221838

  14. Single-photon cooling in a wedge billiard

    SciTech Connect

    Choi, S.; Sundaram, B.; Raizen, M. G.

    2010-09-15

    Single-photon cooling (SPC), noted for its potential as a versatile method for cooling a variety of atomic species, has recently been demonstrated experimentally. In this paper, we study possible ways to improve the performance of SPC by applying it to atoms trapped inside a wedge billiard. The main feature of the wedge billiard for atoms, also experimentally realized recently, is that the nature of atomic trajectories within it changes from stable periodic orbit to random chaotic motion with the change in wedge angle. We find that a high cooling efficiency is possible in this system with a relatively weak dependence on the wedge angle and that chaotic dynamics, rather than a regular orbit, is more desirable for enhancing the performance of SPC.

  15. Ultrasonic fluid densitometer having liquid/wedge and gas/wedge interfaces

    DOEpatents

    Greenwood, Margaret S.

    2000-01-01

    The present invention is an ultrasonic liquid densitometer that uses a material wedge having two sections, one with a liquid/wedge interface and another with a gas/wedge interface. It is preferred that the wedge have an acoustic impedance that is near the acoustic impedance of the liquid, specifically less than a factor of 11 greater than the acoustic impedance of the liquid. Ultrasonic signals are internally reflected within the material wedge. Density of a liquid is determined by immersing the wedge into the liquid and measuring reflections of ultrasound at the liquid/wedge interface and at the gas/wedge interface.

  16. Reverse wedge osteotomy of the distal radius in Madelung's deformity.

    PubMed

    Mallard, F; Jeudy, J; Rabarin, F; Raimbeau, G; Fouque, P-A; Cesari, B; Bizot, P; Saint-Cast, Y

    2013-06-01

    Madelung's deformity results from a growth defect in the palmar and ulnar region of the distal radius. It presents as an excessively inclined radial joint surface, inducing "spontaneous progressive palmar subluxation of the wrist". The principle of reverse wedge osteotomy (RWO) consists in the reorientation of the radial joint surface by taking a circumferential bone wedge, the base of which is harvested from the excess of the radial and dorsal cortical bone of the distal radius, then turning it over and putting back this reverse wedge into the osteotomy so as to obtain closure on the excess and opening on the deficient cortical bone. RWO corrects the palmar subluxation of the carpus and improves distal radio-ulnar alignment. All five bilaterally operated patients were satisfied, esthetically and functionally. Its corrective power gives RWO a place apart among the surgical techniques currently available in Madelung's deformity.

  17. Structure and Kinematics of the Indo-Burmese Wedge

    NASA Astrophysics Data System (ADS)

    Maurin, T.; Rangin, C.

    2007-12-01

    The Burma subduction trench and the associated Indo Burmese wedge mark the present eastern boundary of the Indian plate in the northern Bengal area. The initiation, duration and history of the Bengal crust subduction beneath Burma is still debated. The aim of this paper is to provide a structural and kinematic analysis of the Indo- Burmese wedge in order to better constraints the Bengal crust subduction history beneath Burma. On the basis of field observations, seismic reflection data interpretation and well logs data we present a structural analysis of the Outer Indo-Burmese Wedge. We also constrain the onset of this Outer Wedge to be younger than 2Ma, implying a recent and fast westward growth (~10cm/yr) since Late Pliocene in close relationship with the onset of the Shillong plateau. Restoration process of a synthetic cross section through the Outer Wedge allowed us to estimate the amount of EW shortening accommodated in the Outer Wedge to be 5.1mm/yr since 2Ma. These results combined with previous available GPS data from central Myanmar suggest strain partitioning at wedge scale. The core of the wedge is affected by shear deformation and acts as a buttress for a frontal wedge that accommodates a more compressive strain component. Finally we propose that the main characteristic of the Indo-Burmese wedge growth mechanism is the progressive incorporation of the most internal part of the wedge, formerly affected by transpressive thin-skinned tectonics, to the buttress where they are subsequently affected by shear deformation. The crustal structure boarding the newly formed buttress seems to be guided by the subducting crust fabrics. We are in favour of a very recent (Late Miocene) onset of the present Indian crust subduction beneath Burma coeval with the global plate kinematics reorganisation related to the Indian/Australian plate spliting. This subduction postdates the Indo Burmese range onset that must have started in early Miocene. This range first began to

  18. Structure and Kinematics of the Indo-Burmese Wedge

    NASA Astrophysics Data System (ADS)

    Maurin, T.; Rangin, C.

    2004-12-01

    The Burma subduction trench and the associated Indo Burmese wedge mark the present eastern boundary of the Indian plate in the northern Bengal area. The initiation, duration and history of the Bengal crust subduction beneath Burma is still debated. The aim of this paper is to provide a structural and kinematic analysis of the Indo- Burmese wedge in order to better constraints the Bengal crust subduction history beneath Burma. On the basis of field observations, seismic reflection data interpretation and well logs data we present a structural analysis of the Outer Indo-Burmese Wedge. We also constrain the onset of this Outer Wedge to be younger than 2Ma, implying a recent and fast westward growth (~10cm/yr) since Late Pliocene in close relationship with the onset of the Shillong plateau. Restoration process of a synthetic cross section through the Outer Wedge allowed us to estimate the amount of EW shortening accommodated in the Outer Wedge to be 5.1mm/yr since 2Ma. These results combined with previous available GPS data from central Myanmar suggest strain partitioning at wedge scale. The core of the wedge is affected by shear deformation and acts as a buttress for a frontal wedge that accommodates a more compressive strain component. Finally we propose that the main characteristic of the Indo-Burmese wedge growth mechanism is the progressive incorporation of the most internal part of the wedge, formerly affected by transpressive thin-skinned tectonics, to the buttress where they are subsequently affected by shear deformation. The crustal structure boarding the newly formed buttress seems to be guided by the subducting crust fabrics. We are in favour of a very recent (Late Miocene) onset of the present Indian crust subduction beneath Burma coeval with the global plate kinematics reorganisation related to the Indian/Australian plate spliting. This subduction postdates the Indo Burmese range onset that must have started in early Miocene. This range first began to

  19. Coherent beam combination using self-phase locked stimulated Brillouin scattering phase conjugate mirrors with a rotating wedge for high power laser generation.

    PubMed

    Park, Sangwoo; Cha, Seongwoo; Oh, Jungsuk; Lee, Hwihyeong; Ahn, Heekyung; Churn, Kil Sung; Kong, Hong Jin

    2016-04-18

    The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7. PMID:27137299

  20. Coherent beam combination using self-phase locked stimulated Brillouin scattering phase conjugate mirrors with a rotating wedge for high power laser generation.

    PubMed

    Park, Sangwoo; Cha, Seongwoo; Oh, Jungsuk; Lee, Hwihyeong; Ahn, Heekyung; Churn, Kil Sung; Kong, Hong Jin

    2016-04-18

    The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7.

  1. A depth dependence determination of the wedge transmission factor for 4-10 MV photon beams.

    PubMed

    McCullough, E C; Gortney, J; Blackwell, C R

    1988-01-01

    The depth dependence (up to 25 cm) of the in-phantom wedge transmission factor (WTF) has been determined for three medical linear accelerator x-ray beams with energies of 4, 6, and 10 MV containing 15 degrees-60 degrees (nominal) brass wedges. All measurements were made with a cylindrical ionization chamber in water, for a field size of 10 X 10 cm2 with a source-skin distance of 80 or 100 cm. We conclude that, for the accelerators studied, the WTF factor at depth is less than 2% different from that determined at dmax (for the nominal wedge angles and photon energies studied) unless the depth of interest is greater than 10 cm. Up to the maximum depth studied (25 cm) the relative wedge factor--that is, wedge factor at depth compared to that determined at dmax--was about equal to or less than 1.02 for the 15 degrees and 30 degrees wedges and any of the photon beam energies studied. For the seldom utilized combination of a nominal wedge angle in excess of 45 degrees with a depth greater than 10 cm, the WTF at depth can differ from the WTF determined at dmax, by up to 5%. Since the wedge transmission factor is reflective of relative percent dose data, our results also indicate that it is in error to use open field percent depth doses for certain combinations of wedge angle, photon energy, and depth. PMID:3211057

  2. Study of the impact of truncations on wedge waves by using the laser ultrasound technique.

    PubMed

    Jia, Jing; Shen, Zhonghua; Sun, KaiHua

    2015-08-20

    This research focuses on measuring the impact of truncations on the dispersion characteristics of wedge waves propagating along the wedge tip by using the laser-generated ultrasound. First, the finite element method was used to simulate laser-induced wedge waves and the dispersion curves were obtained by using the 2D Fourier transformation method. Pulsed laser excitation and laser-based wedge wave detection were also utilized to investigate these characteristics experimentally. For the 20° and 60° line wedges, both experimental and numerical results indicated that a nonideal wedge tip had great impact on the wedge waves. The modes of the 20° line wedge with truncations presented anomalous dispersion, low mode closed to high mode in high frequency, and the characteristics of antisymmetric Lamb waves as truncation increased. Meanwhile, the modes of the 60° line wedge with truncations showed the characteristics of antisymmetric Lamb waves, and the A1 mode was also observed clearly. The findings of this study can be used to evaluate and detect wedge structure.

  3. The decay of highly excited open strings

    NASA Technical Reports Server (NTRS)

    Mitchell, D.; Turok, N.; Wilkinson, R.; Jetzer, P.

    1988-01-01

    The decay rates of leading edge Regge trajectory states are calculated for very high level number in open bosonic string theories, ignoring tachyon final states. The optical theorem simplifies the analysis while enabling identification of the different mass level decay channels. The main result is that (in four dimensions) the greatest single channel is the emission of a single photon and a state of the next mass level down. A simple asymptotic formula for arbitrarily high level number is given for this process. Also calculated is the total decay rate exactly up to N=100. It shows little variation over this range but appears to decrease for larger N. The formalism is checked in examples and the decay rate of the first excited level calculated for open superstring theories. The calculation may also have implications for high spin meson resonances.

  4. Wavelength meter having elliptical wedge

    DOEpatents

    Hackel, R.P.; Feldman, M.

    1992-12-01

    A wavelength meter is disclosed which can determine the wavelength of a laser beam from a laser source within an accuracy range of two parts in 10[sup 8]. The wavelength meter has wedge having an elliptically shaped face to the optical path of the laser source and includes interferometer plates which form a vacuum housing. 7 figs.

  5. Wavelength meter having elliptical wedge

    DOEpatents

    Hackel, Richard P.; Feldman, Mark

    1992-01-01

    A wavelength meter is disclosed which can determine the wavelength of a laser beam from a laser source within an accuracy range of two parts in 10.sup.8. The wavelength meter has wedge having an elliptically shaped face to the optical path of the laser source and includes interferometer plates which form a vacuum housing.

  6. Predicting/Extrapolating Active Layer Thickness Using Statistical Learning from Remotely-Sensed High-resolution Data in Arctic Permafrost Landscapes: Improved parameterization of Ice-wedge polygons from LiDAR/WorldView-2 derived metrics

    NASA Astrophysics Data System (ADS)

    Gangodagamage, C.; Rowland, J. C.; Hubbard, S. S.; Brumby, S. P.; Liljedahl, A.; Wainwright, H. M.; Sloan, V. L.; Altmann, G.; Skurikhin, A. N.; Shelef, E.; Wilson, C. J.; Dafflon, B.; Peterson, J.; Ulrich, C.; Gibbs, A.; Tweedie, C. E.; Painter, S. L.; Wullschleger, S. D.

    2014-12-01

    Landscape attributes that vary with micro-topography, such as active layer thickness (ALT) in ice-wedge polygon ground, are labor-intensive to document in the field at large spatial extents, necessitating remotely sensed methods. Robust techniques to estimate ALT over large areas would improve understanding of coupled dynamics between permafrost, hydrology and landsurface processes, and improve simulations of the rate and timing of release of soil carbon from permafrost settings. In particular, it would provide critically needed data to parameterize and initialize soil property information in permafrost models and evaluate model predictions for large, complex domains. In this work, we demonstrate a new data fusion approach using high-resolution remotely sensed data for estimating cm scale ALT in a 5 km2 area of ice-wedge polygon terrain in Barrow, Alaska. We used topographic (directed distance, slope, wavelet-curvature) and spectral (NDVI) metrics derived from multisensor data obtained from LiDAR and WorldView-2 platforms to develop a simple data fusion algorithm using statistical machine learning. This algorithm was used to estimate ALT (2 m spatial resolution) across the study area. A comparison of the estimates with ground-based measurements documented the accuracy (±4.4 cm, r2=0.76) of the approach. Our findings suggest that the broad climatic variability associated with warming air temperature will govern the regional averages of ALT, but the smaller-scale variability could be controlled by local eco-hydro-geomorphic variables. This work demonstrates a path forward for mapping subsurface properties over large areas from readily available remote sensing data. Methodology of Mapping and Characterization Polygons:We convolve LiDAR elevations with multiscale wavelets and objectively chose appropriate scales to map interconnected troughs of high- and low-centered polygons. For the ice wedges where LiDAR surface expressions (troughs) are not well developed, we used

  7. Wedge immersed thermistor bolometer measures infrared radiation

    NASA Technical Reports Server (NTRS)

    Dreyfus, M. G.

    1965-01-01

    Wedge immersed-thermistor bolometer measures infrared radiation in the atmosphere. The thermistor flakes are immersed by optical contact on a wedge-shaped germanium lens whose narrow dimension is clamped between two complementary wedge-shaped germanium blocks bonded with a suitable adhesive.

  8. Single crystal metal wedges for surface acoustic wave propagation

    DOEpatents

    Fisher, E.S.

    1980-05-09

    An ultrasonic testing device has been developed to evaluate flaws and inhomogeneities in the near-surface region of a test material. A metal single crystal wedge is used to generate high frequency Rayleigh surface waves in the test material surface by conversion of a slow velocity, bulk acoustic mode in the wedge into a Rayleigh wave at the metal-wedge test material interface. Particular classes of metals have been found to provide the bulk acoustic modes necessary for production of a surface wave with extremely high frequency and angular collimation. The high frequency allows flaws and inhomogeneities to be examined with greater resolution. The high degree of angular collimation for the outgoing ultrasonic beam permits precision angular location of flaws and inhomogeneities in the test material surface.

  9. Single crystal metal wedges for surface acoustic wave propagation

    DOEpatents

    Fisher, Edward S.

    1982-01-01

    An ultrasonic testing device has been developed to evaluate flaws and inhomogeneities in the near-surface region of a test material. A metal single crystal wedge is used to generate high frequency Rayleigh surface waves in the test material surface by conversion of a slow velocity, bulk acoustic mode in the wedge into a Rayleigh wave at the metal-wedge test material interface. Particular classes of metals have been found to provide the bulk acoustic modes necessary for production of a surface wave with extremely high frequency and angular collimation. The high frequency allows flaws and inhomogeneities to be examined with greater resolution. The high degree of angular collimation for the outgoing ultrasonic beam permits precision angular location of flaws and inhomogeneities in the test material surface.

  10. Tritanium acetabular wedge augments: short-term results

    PubMed Central

    Restrepo, Camilo; Heller, Snir

    2016-01-01

    Background Reconstruction of acetabular defects in total hip arthroplasty (THA) presents a great challenge to orthopaedic surgeons. Previous studies have reported on the use and outcomes of trabecular metal acetabular augments for the reconstruction of acetabular defects. However, no study has been conducted evaluating the short-term results of tritanium acetabular wedge augments for the reconstruction of acetabular defects in THA. Methods A retrospective study was conducted using a prospective database at a single institution including primary and revision THA patients from January 2013 to December 2014. Patients were included if they received a tritanium acetabular wedge augment system and had a minimum of 2-year follow-up (average 2.2 years ±0.3, range, 2–2.6 years). Demographic data and outcomes data [Harris Hip Score—HHS and Short Form (SF)-36] was collected. Radiographic data was also collected on THA revision cases (Paprosky classification), developmental dysplasia of the hip (DDH) cases (Crowe classification), and radiographic follow-up using DeLee and Charnley’s classification system. Results There were 4 revision THA patients, 3 DDH patients, and 1 patient with posttraumatic arthritis. At the latest radiographic follow-up, there were no lucent lines in DeLee and Charnley Zones I, II or III. During the follow-up period, there was no open revision surgery. The SF-36 physical score significantly improved from preoperative measurement (29.6±2.2) to postoperative measurement (52.2±8.7, P=0.003), and the SF-36 mental score also significantly improved from preoperative assessment (34.5±4.5) to postoperative assessment (52.2±7.5, P=0.003). Total HHS scores also significantly improved postoperatively (P=0.02), with significant improvements in both the pain score (P=0.01) and function score (P=0.02). Conclusions Tritanium acetabular wedge augments in this short follow-up case series exhibit high clinical outcome scores, no radiographic lucency, and no

  11. The Influence of Localized Glacial Erosion on Exhumation Paths in Accreting Coulomb Wedges: Insights from Particle Velocimetry Analysis of Sandbox Models

    NASA Astrophysics Data System (ADS)

    Newman, P. J.; Davis, K.; Haq, S. S. B.; Ridgway, K.

    2015-12-01

    Glacial erosion can have an impact on the location and development of faults in mountain belts. The rapid removal and deposition of rock, in some cases, is thought to affect the initiation of slip on older fault structures, or cause the development of new structures within the older part of the wedge. We present cross-sectional data from both erosional and non-erosional sandbox models of Coulomb wedges in order to quantify the impact of localized erosion on the location of and slip on deformational structures, as well as the general path of material through a wedge. To do this, we employ Lagrangian particle tracking velocimetry (PTV) using the open-source Python PTV toolkit trackpy, among a suite of other data analysis tools. We are able to extract robust and reliable sets of particle trajectories from a series of images without the need for predefined markers or marker-beds, instead identifying and tracking natural variations in sand color as individual particles. By comparing the motion of particles in cross-section to the local surface topography over an entire experiment, we determine a high-resolution record of exhumation rates, in addition to simple uplift rates. These comparisons are further informed by the use of high-definition Eulerian particle image velocimetry (PIV), which provides quantitative data about the distribution of deformation and instantaneous material displacements throughout a cross-sectional view of a Coulomb wedge. This allows us to interpret these pathways in relation to the behavior of active structures and general wedge morphology. In our experiments, we observe that localized glacial erosion has an impact on material pathways, in the form of an increased rate of exhumation locally, more vertical trajectories towards surface below the zone of erosion, and reactivation of older structures to maintain force balance within the entire wedge.

  12. Some Historical Treatments should not be Forgotten: A Review of Cast Wedging and A Trick to Normalize Non-Standardized Digital X-rays

    PubMed Central

    Jacobson, Nathan A.; Lee, Christopher L.

    2014-01-01

    Introduction: Cast wedging is a simple and reproducible method of manipulating a sub-optimally reduced fracture producing a correction and a final alignment that is amenable to definitive closed treatment. Multiple successful techniques have been previously described in the literature (opening wedge, closing wedge and combination). Technical Note: We present a simple reproducible method of templating and executing a proper cast wedging technique using digital imaging systems that are not controlled for magnification with an illustrative case. Conclusion: Renewed interest in cast wedging can provide a cost effective treatment with proven clinical outcomes in an ever changing and uncertain reimbursement climate. PMID:27298956

  13. Experimental simulation of frost wedging-induced crack propagation in alpine rockwall

    NASA Astrophysics Data System (ADS)

    Jia, Hailiang; Leith, Kerry; Krautblatter, Michael

    2016-04-01

    Frost wedging is widely presumed to be the principal mechanism responsible for shattering jointed low-porosity rocks in high alpine rockwalls. The interaction of ice and rock physics regulates the efficacy of frost wedging. In order to better understand temporal aspects of this interaction, we present results of a series of laboratory experiments monitoring crack widening as a result of ice formation in an artificial crack (4mm wide, 80mm deep) cut 20 mm from the end of a rectangular granite block. Our results indicate that i) freezing direction plays a key role in determining the magnitude of crack widening; in short-term (1 day) experiments, maximum crack widening during top-down freezing (associated with 'autumn' conditions) was around 0.11mm, while inside-out freezing (resulting from 'spring' conditions) produced only 0.02 mm of deformation; ii) neither ice, nor water pressure (direct tension and hydraulic fracturing respectively) caused measurable irreversible crack widening during short-term tests, as the calculated maximum stress intensity at the crack tip was less than the fracture toughness of our granite sample; iii) development of ice pressure is closely related to the mechanical properties of the fracture in which it forms, and as such, the interaction of ice and rock is intrinsically dynamic; iv) irreversible crack widening (about 0.03mm) was only observed following a long-term (53 day) experiment representing a simplified transition from autumn to winter conditions. We suggest this is the result of stress corrosion aided by strong opening during freezing, and to a lesser degree by ice segregation up to one week after the initial freezing period, and downward migration of liquid water during the remainder of the test. Our results suggest the fundamental assumption of frost wedging, that rapid freezing from open ends of cracks can seal water inside the crack and thus cause damage through excessive stresses induced by volumetric expansion seems

  14. Laboratory and numerical investigation of transport processes occurring above and within a saltwater wedge.

    PubMed

    Chang, Sun Woo; Clement, T Prabhakar

    2013-04-01

    Salt wedges divide coastal groundwater flow regime into two distinct regions that include a freshwater region above the saltwater-freshwater interface and a saltwater region below the interface. Several recent studies have investigated saltwater transport in coastal aquifers and the associated flow and mixing processes. Most of these studies, however, have either focused on studying the movement of salt wedge itself or on studying contaminant transport processes occurring above the wedge. As per our knowledge, so far no one has completed laboratory experiments to study contaminant transport processes occurring within a saltwater wedge. In this study, we completed laboratory experiments to understand contaminant transport dynamics occurring within a saltwater wedge. We used a novel experimental approach that employed multiple neutral-density tracers to map and compare the mixing and transport processes occurring above and within a saltwater wedge. The experimental data were simulated using SEAWAT, and the model was used to further investigate the saltwater flow and transport dynamics within a wedge. The laboratory data show that the transport rates active within the wedge are almost two orders of magnitude slower than the transport rates active above the wedge for the small-scale experimental system which is characterized by very low level of mixing. The numerical results, however, postulate that for large-scale systems involving higher levels of mixing (or dispersion) the transport rate active within the wedge could be comparable or even higher than the rates active above the wedge. More field or laboratory studies completed under high dispersion conditions are needed to further test this hypothesis.

  15. Characterization of CNRS Fizeau wedge laser tuner

    NASA Astrophysics Data System (ADS)

    A fringe detection and measurement system was constructed for use with the CNRS Fizeau wedge laser tuner, consisting of three circuit boards. The first board is a standard Reticon RC-100 B motherboard which is used to provide the timing, video processing, and housekeeping functions required by the Reticon RL-512 G photodiode array used in the system. The sampled and held video signal from the motherboard is processed by a second, custom fabricated circuit board which contains a high speed fringe detection and locating circuit. This board includes a dc level discriminator type fringe detector, a counter circuit to determine fringe center, a pulsed laser triggering circuit, and a control circuit to operate the shutter for the He-Ne reference laser beam. The fringe center information is supplied to the third board, a commercial single board computer, which governs the data collection process and interprets the results.

  16. Characterization of CNRS Fizeau wedge laser tuner

    NASA Technical Reports Server (NTRS)

    1984-01-01

    A fringe detection and measurement system was constructed for use with the CNRS Fizeau wedge laser tuner, consisting of three circuit boards. The first board is a standard Reticon RC-100 B motherboard which is used to provide the timing, video processing, and housekeeping functions required by the Reticon RL-512 G photodiode array used in the system. The sampled and held video signal from the motherboard is processed by a second, custom fabricated circuit board which contains a high speed fringe detection and locating circuit. This board includes a dc level discriminator type fringe detector, a counter circuit to determine fringe center, a pulsed laser triggering circuit, and a control circuit to operate the shutter for the He-Ne reference laser beam. The fringe center information is supplied to the third board, a commercial single board computer, which governs the data collection process and interprets the results.

  17. Depth dependence determination of the wedge transmission factor for 4--10 MV photon beams

    SciTech Connect

    McCullough, E.C.; Gortney, J.; Blackwell, C.R.

    1988-07-01

    The depth dependence (up to 25 cm) of the in-phantom wedge transmission factor (WTF) has been determined for three medical linear accelerator x-ray beams with energies of 4, 6, and 10 MV containing 15/sup 0/--60/sup 0/ (nominal) brass wedges. All measurements were made with a cylindrical ionization chamber in water, for a field size of 10 x 10 cm/sup 2/ with a source--skin distance of 80 or 100 cm. We conclude that, for the accelerators studied, the WTF factor at depth is less than 2% different from that determined at d/sub max/ (for the nominal wedge angles and photon energies studied) unless the depth of interest is greater than 10 cm. Up to the maximum depth studied (25 cm) the relative wedge factor: that is, wedge factor at depth compared to that determined at d/sub max/ : was about equal to or less than 1.02 for the 15/sup 0/ and 30/sup 0/ wedges and any of the photon beam energies studied. For the seldom utilized combination of a nominal wedge angle in excess of 45/sup 0/ with a depth greater than 10 cm, the WTF at depth can differ from the WTF determined at d/sub max/, by up to 5%. Since the wedge transmission factor is reflective of relative percent dose data, our results also indicate that it is in error to use open field percent depth doses for certain combinations of wedge angle, photon energy, and depth.

  18. Pseudo-ice-wedge casts of Connecticut, northeastern United States

    NASA Astrophysics Data System (ADS)

    Black, Robert F.

    1983-07-01

    Since 1965, ice-wedge casts have been reported in deposits of sand and gravel in Connecticut. These are wedge forms up to 1.1 m wide and many meters high. Most are single forms, not in polygonal array. They are found in adjoining states as well. Their distribution, dimensions, structure, and fabric and an assessment of the former physical environment preclude their origin as permafrost features. They appear to be tension fractures produced by the loading of coarse clastics on fine clastics near and below the water table where sediments creep toward a stream or depression. Locally movement started with kettle formation during deglaciation. However, some wedges cut horizontal layers of iron-coated sand and gravel and must be younger than those distinctly postglacial phenomena. Moreover, modern B horizons of the overlying soil have moved down into some wedges more than 2 m, indicating that fracturing is still active today. Complex fracture fillings in bedrock also have been attributed to a permafrost origin, but this too seems unlikely.

  19. Isolating active orogenic wedge deformation in the southern Subandes of Bolivia

    NASA Astrophysics Data System (ADS)

    Weiss, Jonathan R.; Brooks, Benjamin A.; Foster, James H.; Bevis, Michael; Echalar, Arturo; Caccamise, Dana; Heck, Jacob; Kendrick, Eric; Ahlgren, Kevin; Raleigh, David; Smalley, Robert; Vergani, Gustavo

    2016-08-01

    A new GPS-derived surface velocity field for the central Andean backarc permits an assessment of orogenic wedge deformation across the southern Subandes of Bolivia, where recent studies suggest that great earthquakes (>Mw 8) are possible. We find that the backarc is not isolated from the main plate boundary seismic cycle. Rather, signals from subduction zone earthquakes contaminate the velocity field at distances greater than 800 km from the Chile trench. Two new wedge-crossing velocity profiles, corrected for seasonal and earthquake affects, reveal distinct regions that reflect (1) locking of the main plate boundary across the high Andes, (2) the location of and loading rate at the back of orogenic wedge, and (3) an east flank velocity gradient indicative of décollement locking beneath the Subandes. Modeling of the Subandean portions of the profiles indicates along-strike variations in the décollement locked width (WL) and wedge loading rate; the northern wedge décollement has a WL of ~100 km while accumulating slip at a rate of ~14 mm/yr, whereas the southern wedge has a WL of ~61 km and a slip rate of ~7 mm/yr. When compared to Quaternary estimates of geologic shortening and evidence for Holocene internal wedge deformation, the new GPS-derived wedge loading rates may indicate that the southern wedge is experiencing a phase of thickening via reactivation of preexisting internal structures. In contrast, we suspect that the northern wedge is undergoing an accretion or widening phase primarily via slip on relatively young thrust-front faults.

  20. Capillarity driven motion of solid film wedges

    SciTech Connect

    Wong, H.; Miksis, M.J.; Voorhees, P.W.; Davis, S.H.

    1997-06-01

    A solid film freshly deposited on a substrate may form a non-equilibrium contact angle with the substrate, and will evolve. This morphological evolution near the contact line is investigated by studying the motion of a solid wedge on a substrate. The contact angle of the wedge changes at time t = 0 from the wedge angle {alpha} to the equilibrium contact angle {beta}, and its effects spread into the wedge via capillarity-driven surface diffusion. The film profiles at different times are found to be self-similar, with the length scale increasing as t{sup 1 4}. The self-similar film profile is determined numerically by a shooting method for {alpha} and {beta} between 0 and 180. In general, the authors find that the film remains a wedge when {alpha} = {beta}. For {alpha} < {beta}, the film retracts, whereas for {alpha} > {beta}, the film extends. For {alpha} = 90{degree}, the results describe the growth of grain-boundary grooves for arbitrary dihedral angles. For {beta} = 90{degree}, the solution also applies to a free-standing wedge, and the thin-wedge profiles agree qualitatively with those observed in transmission electron microscope specimens.

  1. Pressure Distributions About Finite Wedges in Bounded and Unbounded Subsonic Streams

    NASA Technical Reports Server (NTRS)

    Donoughe, Patrick L; Prasse, Ernst I

    1953-01-01

    An analytical investigation of incompressible flow about wedges was made to determine effects of tunnel-wedge ratio and wedge angle on the wedge pressure distributions. The region of applicability of infinite wedge-type velocity distribution was examined for finite wedges. Theoretical and experimental pressure coefficients for various tunnel-wedge ratios, wedge angles, and subsonic Mach numbers were compared.

  2. Sol-gel based anti-reflection coatings on wedged laser rods using a spin coater

    NASA Astrophysics Data System (ADS)

    Pareek, R.; Joshi, A. S.; Gupta, P. D.; Biswas, P. K.; Das, S.

    2005-07-01

    Anti-reflection (AR) sol-gel coatings are deposited on wedge glass optics for high-power lasers using spin coating technique. Characterization of these coatings on BK-7 glass substrates is carried out in terms of thickness profile across the surface, thickness variation w.r.t. wedge angle, and its effect on AR coating reflectivity, at different wedge angles from 1° to 7°. Results of the study are used to deposit AR coatings on inclined end faces of Nd:phosphate glass laser rods.

  3. Long-range hybrid wedge plasmonic waveguide.

    PubMed

    Zhang, Zhonglai; Wang, Jian

    2014-11-03

    We design a novel long-range hybrid wedge plasmonic (LRHWP) waveguide composed of two identical dielectric nanowires symmetrically placed on two opposed wedges of a diamond shaped metal wire. With strong coupling between the dielectric nanowire mode and long-range surface plasmon polariton (SPP) mode, both deep subwavelength mode confinement and low propagation loss are achieved. On one hand, when compared to the previous long-range hybrid SPP waveguide, LRHWP waveguide can achieve smaller mode size with similar propagation length; on the other hand, when compared to the previous hybrid wedge SPP waveguide, LRHWP waveguide can provide an order of magnitude longer propagation length with similar level of mode confinement. The designed LRHWP waveguide also features an overall advantage of one-order improvement of Figure of Merit. We further evaluate in detail the impacts of possible practical fabrication imperfections on the mode properties. The obtained results of mode properties show that the proposed LRHWP waveguide with an optimized wedge tip angle of 140 degree is fairly tolerant to practical fabrication errors in geometry parameters such as misalignment in the horizontal direction, asymmetry in the vertical direction, variation of wedge tip angle, tilt or rotation of metal wire, and variation of wedge tip curvature radius.

  4. Long-range hybrid wedge plasmonic waveguide.

    PubMed

    Zhang, Zhonglai; Wang, Jian

    2014-01-01

    We design a novel long-range hybrid wedge plasmonic (LRHWP) waveguide composed of two identical dielectric nanowires symmetrically placed on two opposed wedges of a diamond shaped metal wire. With strong coupling between the dielectric nanowire mode and long-range surface plasmon polariton (SPP) mode, both deep subwavelength mode confinement and low propagation loss are achieved. On one hand, when compared to the previous long-range hybrid SPP waveguide, LRHWP waveguide can achieve smaller mode size with similar propagation length; on the other hand, when compared to the previous hybrid wedge SPP waveguide, LRHWP waveguide can provide an order of magnitude longer propagation length with similar level of mode confinement. The designed LRHWP waveguide also features an overall advantage of one-order improvement of Figure of Merit. We further evaluate in detail the impacts of possible practical fabrication imperfections on the mode properties. The obtained results of mode properties show that the proposed LRHWP waveguide with an optimized wedge tip angle of 140 degree is fairly tolerant to practical fabrication errors in geometry parameters such as misalignment in the horizontal direction, asymmetry in the vertical direction, variation of wedge tip angle, tilt or rotation of metal wire, and variation of wedge tip curvature radius. PMID:25362900

  5. A Study in Wedge Waves with Applications in Acoustic Delay- line

    NASA Astrophysics Data System (ADS)

    Tung, Po-Hsien; Wang, Wen-Chi; Yang, Che-Hua

    The acoustic delay line is usually used to supply protection from dangerous environment, to enhance signal intensity by fit geometry of analyte, or to achieve specific angle/focusing by Snell's law, but rarely to avoid noise from coupling agent and to raise spatial resolution by reducing contact area. This study is focused on wedge waves with applications in delay-line to solve the knot of traditionally transducer measurement. Wedge waves are guided acoustic waves propagating along the tip of a wedge. The advantages of wedge being used in acoustic delay line are wedge waves has large motion amplitude of anti-symmetric flexural (ASF) mode, low energy attenuation and the velocity of ASF more is regular weather frequency varied or not. According the characteristic of wedge wave and vibration direction of particle, the acoustical wedge delay line with high signal- noise-ratio, approximate point-like contact area, without coupling agent and in/out vibration measurement by specific experimental setup is developed.

  6. Semi-analytical solutions of groundwater flow in multi-zone (patchy) wedge-shaped aquifers

    NASA Astrophysics Data System (ADS)

    Samani, Nozar; Sedghi, Mohammad M.

    2015-03-01

    Alluvial fans are potential sites of potable groundwater in many parts of the world. Characteristics of alluvial fans sediments are changed radially from high energy coarse-grained deposition near the apex to low energy fine-grained deposition downstream so that patchy wedge-shaped aquifers with radial heterogeneity are formed. The hydraulic parameters of the aquifers (e.g. hydraulic conductivity and specific storage) change in the same fashion. Analytical or semi-analytical solutions of the flow in wedge-shaped aquifers are available for homogeneous cases. In this paper we derive semi-analytical solutions of groundwater flow to a well in multi-zone wedge-shaped aquifers. Solutions are provided for three wedge boundary configurations namely: constant head-constant head wedge, constant head-barrier wedge and barrier-barrier wedge. Derivation involves the use of integral transforms methods. The effect of heterogeneity ratios of zones on the response of the aquifer is examined. The results are presented in form of drawdown and drawdown derivative type curves. Heterogeneity has a significant effect on over all response of the pumped aquifer. Solutions help understanding the behavior of heterogeneous multi-zone aquifers for sustainable development of the groundwater resources in alluvial fans.

  7. Dual Double-Wedge Pseudo-Depolarizer with Anamorphic PSF

    NASA Technical Reports Server (NTRS)

    Hill, Peter; Thompson, Patrick

    2012-01-01

    A polarized scene, which may occur at oblique illumination angles, creates a radiometric signal that varies as a function of viewing angle. One common optical component that is used to minimize such an effect is a polarization scrambler or depolarizer. As part of the CLARREO mission, the SOLARIS instrument project at Goddard Space Flight Center has developed a new class of polarization scramblers using a dual double-wedge pseudo-depolarizer that produces an anamorphic point spread function (PSF). The SOLARIS instrument uses two Wollaston type scramblers in series, each with a distinct wedge angle, to image a pseudo-depolarized scene that is free of eigenstates. Since each wedge is distinct, the scrambler is able to produce an anamorphic PSF that maintains high spatial resolution in one dimension by sacrificing the spatial resolution in the other dimension. This scrambler geometry is ideal for 1-D imagers, such as pushbroom slit spectrometers, which require high spectral resolution, high spatial resolution, and low sensitivity to polarized light. Moreover, the geometry is applicable to a wide range of scientific instruments that require both high SNR (signal-to-noise ratio) and low sensitivity to polarized scenes

  8. Dynamic Open Inquiry Performances of High-School Biology Students

    ERIC Educational Resources Information Center

    Zion, Michal; Sadeh, Irit

    2010-01-01

    In examining open inquiry projects among high-school biology students, we found dynamic inquiry performances expressed in two criteria: "changes occurring during inquiry" and "procedural understanding". Characterizing performances in a dynamic open inquiry project can shed light on both the procedural and epistemological scientific understanding…

  9. Transonic Aerodynamic Characteristics of Two Wedge Airfoil Sections Including Unsteady Flow Studies

    NASA Technical Reports Server (NTRS)

    Johnston, Patrick J.

    1959-01-01

    A two-dimensional wind-tunnel investigation has been conducted on a 20-percent-thick single-wedge airfoil section. Steady-state forces and moments were determined from pressure measurements at Mach numbers from 0.70 to about 1.25. Additional information on the flows about the single wedge is provided by means of instantaneous pressure measurements at Mach numbers up to unity. Pressure distributions were also obtained on a symmetrical double-wedge or diamond-shaped profile which had the same leading-edge included angle as the single-wedge airfoil. A comparison of the data on the two profiles to provide information on the effects of the afterbody showed that with the exception of drag, the single-wedge profile proved to be aerodynamically superior to the diamond profile in all respects. The lift effectiveness of the single-wedge airfoil section far exceeded that of conventional thin airfoil sections over the speed range of the investigation. Pitching-moment irregularities, caused by negative loadings near the trailing edge, generally associated with conventional airfoils of equivalent thicknesses were not exhibited by the single-wedge profile. Moderately high pulsating pressures existing over the base of the single-wedge airfoil section were significantly reduced as the Mach number was increased beyond 0.92 and the boundaries of the dead airspace at the base of the model converged to eliminate the vortex street in the wake. Increasing the leading-edge radius from 0 to 1 percent of the chord had a minor effect on the steady-state forces and generally raised the level of pressure pulsations over the forward part of the single-wedge profile.

  10. Ground Penetrating Radar Detection of Ice Wedge Geometry: Implications for Climate Change Monitoring

    NASA Astrophysics Data System (ADS)

    Williams, K. K.; Haltigin, T.; Pollard, W. H.

    2011-12-01

    Polygonal features in the Canadian High Arctic are found in many areas, have diverse appearances, and occur in a variety of surface materials. As part of a larger project using geophysical methods to study ice wedge depth, width, and thickness, ground penetrating radar (GPR) data were collected across polygonal surface features on Devon Island. As with polygonal features in other locations on Earth, not all of the features studied on Devon Island contain subsurface ice, however polygons with notable surface troughs did contain fairly large ice wedges. The polygons in this study were formed in fine sediments near Thomas Lee Inlet east of the Haughton impact crater, and GPR data were collected at 200 MHz and 400 MHz using the GSSI, Inc. SIR-3000 system. Although both GPR and capacity-coupled resistivity (CCR) data were collected, the CCR data may have been adversely affected by melt water at the base of the active layer. Conversely, the GPR data show the thickness of the active layer, the width of the top of the ice wedge, and other subsurface stratigraphic features very well. Locations and widths of wedge ice were confirmed by augering and trenching to the tops of the ice wedges. GPR data clearly delineate the edges of the tops of ice wedges. Interestingly, the GPR-determined edges correlate with surface tensional cracks that appear to be related to subsidence above the wedge. It is possible that this subsidence is caused by an increase in active layer thickness and downward melting of the ice wedge in response to increasing temperatures over several years or more. If this is the case, small amounts of surface subsidence above ice wedges could be a useful indicator of past and current climate change in Arctic regions. To address this possibility, a broader study is proposed.

  11. Effect of Turbulizing Grid Near Wake on a Boundary Layer on a Wedge

    NASA Astrophysics Data System (ADS)

    Brylyakov, A. P.; Zanin, B. Yu.; Zharkova, G. M.; Sboev, D. S.

    2002-07-01

    The problem of flow about bodies with high free stream turbulence is very important for engineering, because these flows are frequently met in different technical devices and turbo-machines. The recent researches showed that a stationary system of longitudinal structures arose on the winward side of the wing from increasing level of free stream turbulence to 1%. Characteristic transversal size of these structures exceeded the boundary layer thickness in many times. The number of the structures was found to be dependent on the angle of attack and the distance from the wind tunnel nozzle. Those experiments were carried in the open test section and the flow about the wing was complicated because of transversal spread of the flow. The present work is an experimental investigation of a similar phenomenon which takes place in a boundary layer on the winward surface of two-dimensional wedge in close test section.

  12. Geomorphological-thermo-mechanical modeling: Application to orogenic wedge dynamics

    NASA Astrophysics Data System (ADS)

    Ueda, K.; Willett, S. D.; Gerya, T.; Ruh, J.

    2015-09-01

    Coupled geomorphological-thermo-mechanical modeling is presented in a new implementation that combines two established thermo-mechanical and landscape evolution models. A finite-difference marker-in-cell technique is used to solve for the thermo-mechanical problem including complex visco-plastic rheologies in high resolution. Each timestep is synchronously solved with a fluvial landscape evolution model that includes numerical solution of fluvial incision and analytical hillslope processes for both diffusive and slope-limited processes on an adaptive grid. The implementation is successful in modeling large deformation at different scales. We demonstrate high degrees of coupling through processes such as exhumation of rocks with different erodibilities. Sensitivity of the coupled system evolution to surface parameters, and mechanical parameters, is explored for the established case of development of compressive wedges. The evolution of wedge models proves to be primarily sensitive to erodibility and the degree of river network integration. Relief follows deformation in propagating forward with wedge growth. We apply the method to a large-scale model of continental collision, in which a close relationship between deep tectonics, fluvial network evolution, and uplift and erosion can be demonstrated.

  13. Wedge indentation of an elastoviscoplastic material

    NASA Astrophysics Data System (ADS)

    Huang, Zhihong; Lucas, Margaret; Adams, Michael J.

    2002-05-01

    This paper describes the modeling of the indentation of an elasto-viscoplastic material. The finite element code ABAQUS was used to study the bulk mechanical, thermal and interface frictional characteristics for rigid wedge indenters. A series of simulations has been performed at a constant velocity to prescribed depths of penetration for a range of wedge surface temperatures and semi-included angles. Selected experimental data are provided as a basis for validating the numerical simulation. In the simulations, the constitutive behavior of the model material Plasticine is treated as non-linear elasto-viscoplastic, in which the stress scales linearly with the elastic strain and non-linearly with the plastic strain rate. The result demonstrate that the FE simulations agree well with the experimental dat of displacement, strain and stress for all the range of wedge angles and temperatures examined.

  14. Shock interaction mechanisms on a double wedge at Mach 7

    NASA Astrophysics Data System (ADS)

    Durna, Ahmet Selim; El Hajj Ali Barada, Mohamad; Celik, Bayram

    2016-09-01

    Present computational study investigates formation and interaction mechanisms of shocks and boundary layer for low enthalpy Mach 7 flows of nitrogen over double wedges, which have fixed fore and various aft angles of 30° and 45°-60°, respectively. We use a density based finite-volume Navier-Stokes solver to simulate low enthalpy Mach 7 flows of nitrogen over double wedges. The solver is first and second order accurate in time and space, respectively. The meshes used in simulations of two-dimensional laminar flows consist of multiple blocks of structured mesh. Depending on the intensity, impingement angle, and impingement location of transmitted shock wave, the resulting adverse pressure gradient related disturbances on the wedge surface can trigger complex flow physics both in subsonic and supersonic regions. We observe a strong interaction between the deformation of the boundary layer and the bow shock as well as the transmitted shock for high aft angles. Comparison of the obtained results in terms of general flow physics shows that there exists an aft angle threshold value for such interaction which is in the range of 45°-50°.

  15. The wedge hot-film anemometer in supersonic flow

    NASA Technical Reports Server (NTRS)

    Seiner, J. M.

    1983-01-01

    A commercial wedge hot-film probe is studied to determine its heat transfer response in transonic to low supersonic flows of high unit Reynolds number. The results of this study show that its response in this flow regime differs from the response of cylindrical type sensors. Whereas the cylindrical sensor has the same sensitivity to velocity as to density for free-stream Mach numbers exceeding 1.3, the wedge probe sensitivity to velocity is always greater than its sensitivity to density over the entire flow regime. This property requires determination of three fluctuation components due to density, velocity, and temperature, in a transonic or supersonic turbulent flow. Sensitivity equations are derived based on the observed behavior of the wedge probe. Both the durability and the frequency response of the probe are excellent, the square wave insertion test indicating frequency response near 130 kHz. The directional response of the probe at sonic speed is poor and requires further examination before Reynolds stress measurements are attempted with dual sensor probes.

  16. Long range hybrid tube-wedge plasmonic waveguide with extreme light confinement and good fabrication error tolerance.

    PubMed

    Ding, Li; Qin, Jin; Xu, Kai; Wang, Liang

    2016-02-22

    We studied a novel long range hybrid tube-wedge plasmonic (LRHTWP) waveguide consisting of a high index dielectric nanotube placed above a triangular metal wedge substrate. Using comprehensive numerical simulations on guiding properties of the designed waveguide, it is found that extreme light confinement and low propagation loss are obtained due to strong coupling between dielectric nanotube mode and wedge plasmon polariton. Comparing with previous studied hybrid plasmonic waveguides, the LRHTWP waveguide has longer propagation length and tighter mode confinement. In addition, the LRHTWP waveguide is quite tolerant to practical fabrication errors such as variation of the wedge tip angle and the horizontal misalignment between the nanotube and the metal wedge. The proposed LRHTWP waveguide could have many application potentials for various high performance nanophotonic components.

  17. A review of dynamics modelling of friction wedge suspensions

    NASA Astrophysics Data System (ADS)

    Wu, Qing; Cole, Colin; Spiryagin, Maksym; Sun, Yan Quan

    2014-11-01

    Three-piece bogies with friction wedge suspensions are the most widely used bogies in heavy haul trains. Fiction wedge suspensions play a key role in these wagon systems. This article reviews current techniques in dynamic modelling of friction wedge suspension with various motivations: to improve dynamic models of friction wedge suspensions so as to improve general wagon dynamics simulations; to seek better friction wedge suspension models for wagon stability assessments in complex train systems; to improve the modelling of other friction devices, such as friction draft gear. Relevant theories and friction wedge suspension models developed by using commercial simulation packages and in-house simulation packages are reviewed.

  18. Rainfall induced groundwater mound in wedge-shaped promontories: The Strack-Chernyshov model revisited

    NASA Astrophysics Data System (ADS)

    Kacimov, A. R.; Kayumov, I. R.; Al-Maktoumi, A.

    2016-11-01

    An analytical solution to the Poisson equation governing Strack's discharge potential (squared thickness of a saturated zone in an unconfined aquifer) is obtained in a wedge-shaped domain with given head boundary conditions on the wedge sides (specified water level in an open water body around a porous promontory). The discharge vector components, maximum elevation of the water table in promontory vertical cross-sections, quantity of groundwater seeping through segments of the wedge sides, the volume of fresh groundwater in the mound are found. For acute angles, the solution to the problem is non-unique and specification of the behaviour at infinity is needed. A "basic" solution is distinguished, which minimizes the water table height above a horizontal bedrock. MODFLOW simulations are carried out in a finite triangular island and compare solutions with a constant-head, no-flow and "basic" boundary condition on one side of the triangle. Far from the tip of an infinite-size promontory one has to be cautious with truncation of the simulated flow domains and imposing corresponding boundary conditions. For a right and obtuse wedge angles, there are no positive solutions for the case of constant accretion on the water table. In a particular case of a confined rigid wedge-shaped aquifer and incompressible fluid, from an explicit solution to the Laplace equation for the hydraulic head with arbitrary time-space varying boundary conditions along the promontory rays, essentially 2-D transient Darcian flows within the wedge are computed. They illustrate that surface water waves on the promontory boundaries can generate strong Darcian waves inside the porous wedge. Evaporation from the water table and sea-water intruded interface (rather than a horizontal bed) are straightforward generalizations for the Poissonian Strack potential.

  19. Testing the critical Coulomb wedge theory on hyper-extended rifted margins

    NASA Astrophysics Data System (ADS)

    Nirrengarten, Michael; Manatschal, Gianreto; Kusznir, Nick

    2015-04-01

    Deformation of hyper-extended continental crust and its relationship with the underlying mantle is a key process in the evolution of rifted margins. Recent studies have focused on hyper-extension in rifted margins using different approaches such as numerical modelling, seismic interpretation, potential field methods and field observations. However many fundamental questions about the observed structures and their evolution during the formation of hyper-extended margins are still debated. In this study an observation driven approach has been used to characterise geometrical and physical attributes of the continental crust termination, considered as a hyper-extended wedge, in order to test the applicability of critical Coulomb wedge theory to hyper-extended margins. The Coulomb wedge theory was first developed on accretionary prisms and on fold and thrust belts, but it has also been applied in extensional settings. Coulomb wedge theory explains the evolution of the critical aperture angle of the wedge as a function of basal sliding without deformation in the overlying wedge. This critical angle depends on the frictional parameters of the material, the basal friction, the surface slope, the basal dip and the fluid pressure. If the evolution of hyper-extended wedges could be described by the critical Coulomb wedge theory, it would have a major impact in the understanding of the structural and physical evolution of rifted domains during the hyper-extension processes. On seismic reflection lines imaging magma-poor hyper-extended margins, the continental crust termination is often shown to form a hyper-extended wedge. ODP Sites 1067, 900 and 1068 on the Iberian margin as well as field observations in the Alps give direct access to the rocks forming the hyper-extended wedge, which are typically composed of highly deformed and hydrated continental rocks underlain by serpentinised mantle. The boundary between the hydrated continental and mantle rocks corresponds to a

  20. Crustal wedge deformation in an internally-driven, numerical subduction model

    NASA Astrophysics Data System (ADS)

    van Dinther, Ylona; Morra, Gabriele; Funiciello, Francesca; Rossetti, Federico; Faccenna, Claudio

    2010-05-01

    The Earth's active convergent margins are characterized by dynamic feedback mechanisms that interact to form an intricate system in which a crustal wedge is shaped and metamorphosed at the will of two large, converging plates. This framework is accompanied by complicated processes, such as seismogenesis and the exhumation of high pressure rocks. To honor the dynamic interaction between different entities and advance on these persisting issues, we model the interaction between the subducting and overriding lithospheres, the mantle and the crustal wedge explicitly, and observe how a crustal wedge evolves in detail within a set of rigid, internally-driven boundary conditions. We model crustal wedge evolution in an intra-oceanic subduction setting by using a plane-strain implicit solid-mechanical Finite Element Model, in which the mechanical conservation equations are solved using the software package ABAQUS. The crustal wedge is modeled as a thick-skinned accretionary wedge of inter-mediate thickness with a linear visco-elastic bulk rheology. The dynamic interaction between the subducting plate, the overriding plate, and crustal wedge is implemented using a Coulomb frictional algorithm. The interaction with the mantle is incorporated using a computationally favorable mantle drag formulation that simulates induced three-dimensional mantle flow. This results in a quasi-static framework with a freely moving slab, trench, and fault, where a weaker wedge deforms in response to self-regulating, rigid boundary conditions formed by single, frictional bounding faults. The self-regulating evolution of crustal wedge architecture follows three phases; 1) initial vertical growth, 2) coeval compression and extension leading to internal corner flow, and 3) a steady-state taper with continuous corner flow. Particle trajectories show that, as shortening continues throughout the second phase, wedge material is constantly forced upward against the backstop, while extension and ocean

  1. Wedge Shock and Nozzle Exhaust Plume Interaction in a Supersonic Jet Flow

    NASA Technical Reports Server (NTRS)

    Castner, Raymond; Zaman, Khairul; Fagan, Amy; Heath, Christopher

    2014-01-01

    Fundamental research for sonic boom reduction is needed to quantify the interaction of shock waves generated from the aircraft wing or tail surfaces with the nozzle exhaust plume. Aft body shock waves that interact with the exhaust plume contribute to the near-field pressure signature of a vehicle. The plume and shock interaction was studied using computational fluid dynamics and compared with experimental data from a coaxial convergent-divergent nozzle flow in an open jet facility. A simple diamond-shaped wedge was used to generate the shock in the outer flow to study its impact on the inner jet flow. Results show that the compression from the wedge deflects the nozzle plume and shocks form on the opposite plume boundary. The sonic boom pressure signature of the nozzle exhaust plume was modified by the presence of the wedge. Both the experimental results and computational predictions show changes in plume deflection.

  2. Robustness of oscillatory α2 dynamos in spherical wedges

    NASA Astrophysics Data System (ADS)

    Cole, E.; Brandenburg, A.; Käpylä, P. J.; Käpylä, M. J.

    2016-10-01

    Context. Large-scale dynamo simulations are sometimes confined to spherical wedge geometries by imposing artificial boundary conditions at high latitudes. This may lead to spatio-temporal behaviours that are not representative of those in full spherical shells. Aims: We study the connection between spherical wedge and full spherical shell geometries using simple mean-field dynamos. Methods: We solve the equations for one-dimensional time-dependent α2 and α2Ω mean-field dynamos with only latitudinal extent to examine the effects of varying the polar angle θ0 between the latitudinal boundaries and the poles in spherical coordinates. Results: In the case of constant α and ηt profiles, we find oscillatory solutions only with the commonly used perfect conductor boundary condition in a wedge geometry, while for full spheres all boundary conditions produce stationary solutions, indicating that perfect conductor conditions lead to unphysical solutions in such a wedge setup. To search for configurations in which this problem can be alleviated we choose a profile of the turbulent magnetic diffusivity that decreases toward the poles, corresponding to high conductivity there. Oscillatory solutions are now achieved with models extending to the poles, but the magnetic field is strongly concentrated near the poles and the oscillation period is very long. By changing both the turbulent magnetic diffusivity and α profiles so that both effects are more concentrated toward the equator, we see oscillatory dynamos with equatorward drift, shorter cycles, and magnetic fields distributed over a wider range of latitudes. Those profiles thus remove the sensitive and unphysical dependence on θ0. When introducing radial shear, we again see oscillatory dynamos, and the direction of drift follows the Parker-Yoshimura rule. Conclusions: A reduced α effect near the poles with a turbulent diffusivity concentrated toward the equator yields oscillatory dynamos with equatorward migration and

  3. Assessment of a multibeam Fizeau wedge interferometer for Doppler wind lidar.

    PubMed

    McKay, Jack A

    2002-03-20

    The Fabry-Perot interferometer is the standard instrument for the direct detection Doppler lidar measurement of atmospheric wind speeds. The multibeam Fizeau wedge has some practical advantages over the Fabry-Perot, such as the linear fringe pattern, and is evaluated for this application. The optimal Fizeau must have a resolving power of 10(6) or more. As the multibeam Fizeau wedge is pushed to such high resolving power, the interference fringes of the device become complicated by asymmetry and secondary maxima. A simple condition for the interferometer plate reflectance, optical gap, and wedge angle reveals whether a set of parameters will yield simple, Airy-like fringes or complex Fizeau fringes. Tilting of the Fizeau wedge improves the fringe shape and permits an extension of the regime of Airy-like fringes to higher resolving power. Sufficient resolving power for the wind lidar application is shown to be possible with a large-gap, low-finesse multibeam Fizeau wedge. Liabilities of the multibeam Fizeau wedge in the wind lidar application include a smaller acceptance solid angle and calibration sensitivity to localized deviations of the plates from the ideal. PMID:11921807

  4. Assessment of a multibeam Fizeau wedge interferometer for Doppler wind lidar.

    PubMed

    McKay, Jack A

    2002-03-20

    The Fabry-Perot interferometer is the standard instrument for the direct detection Doppler lidar measurement of atmospheric wind speeds. The multibeam Fizeau wedge has some practical advantages over the Fabry-Perot, such as the linear fringe pattern, and is evaluated for this application. The optimal Fizeau must have a resolving power of 10(6) or more. As the multibeam Fizeau wedge is pushed to such high resolving power, the interference fringes of the device become complicated by asymmetry and secondary maxima. A simple condition for the interferometer plate reflectance, optical gap, and wedge angle reveals whether a set of parameters will yield simple, Airy-like fringes or complex Fizeau fringes. Tilting of the Fizeau wedge improves the fringe shape and permits an extension of the regime of Airy-like fringes to higher resolving power. Sufficient resolving power for the wind lidar application is shown to be possible with a large-gap, low-finesse multibeam Fizeau wedge. Liabilities of the multibeam Fizeau wedge in the wind lidar application include a smaller acceptance solid angle and calibration sensitivity to localized deviations of the plates from the ideal.

  5. Simultaneous measurement of refractive index and wedge angle of optical windows using Fizeau interferometry and a cyclic path optical configuration

    SciTech Connect

    Kumar, Y. Pavan; Chatterjee, Sanjib

    2009-08-20

    We present a new technique for the simultaneous measurement of refractive index and wedge angle of optical windows using Fizeau interferometry and a cyclic path optical configuration (CPOC). Two laterally separated beams are obtained from an expanded collimated beam using an aperture containing two rectangular openings. The test wedge plate is placed in one of the two separated beams. Using CPOC, these two beams are made to overlap and interfere, producing interference fringes in the overlapping region. The beams reflected from the front and back surfaces of the test wedge plate interfere and produce Fizeau fringes. The refractive index is related to the spacing of the above two beam fringes. The wedge angle is determined from the evaluated values of the refractive index and Fizeau fringe spacing. The results obtained for a BK-7 optical window are presented.

  6. Modes in Lined Wedge-Shaped Ducts

    NASA Astrophysics Data System (ADS)

    Mechel, F. P.

    1998-10-01

    The computation of sound fields in wedge-shaped spaces with an absorbing boundary (the seabed) is a classical problem of underwater acoustics, covered by a large number of publications. All known solutions are approximations which are restricted to very small wedge angles θ0, typically less than 3°. In underwater acoustics it is further assumed thatk0r≫1. The background of the present paper is the performance of lined conical duct sections in silencers. There the wedge angle can attain values around 45°, and the assumptionk0r≫1 cannot be made. The absorber of the lined boundary here is supposed to be locally reacting (for reasons of simplicity); it can be characterized by a normalized surface admittanceG0. The problems of the analysis arise from the fact, that the fundamental field solutions (modes) can no longer be separated in the cylindrical co-ordinatesr, θ if a boundary is absorbing. This paper describes analytical solutions for the construction of modes in lined wedge-shaped ducts; they can be applied for wedge angles up to about 15° (a subsequent paper will describe a method for angles up to about 45° but only moderatek0rvalues). In the solutions, use is made of “fictitious modes”, which satisfy the boundary conditions and solve a part of the wave equation. They must be completed by a “modal rest” to satisfy approximately the full wave equation. In the first solution, the rest is synthesized by fictitious modes; in the second solution, a separate function is introduced for the rest. Modes for typical underwater acoustics conditions will arise as side products.

  7. Late Holocene stable-isotope based winter temperature records from ice wedges in the Northeast Siberian Arctic

    NASA Astrophysics Data System (ADS)

    Opel, Thomas; Meyer, Hanno; Laepple, Thomas; Dereviagin, Alexander Yu.

    2016-04-01

    The Arctic is currently undergoing an unprecedented warming. This highly dynamic response on changes in climate forcing and the global impact of the Arctic water, carbon and energy balances make the Arctic a key region to study past, recent and future climate changes. Recent proxy-based temperature reconstructions indicate a long-term cooling over the past about 8 millennia that is mainly related to a decrease in solar summer insolation and has been reversed only by the ongoing warming. Climate model results on the other hand show no significant change or even a slight warming over this period. This model-proxy data mismatch might be caused by a summer bias of the used climate proxies. Ice wedges may provide essential information on past winter temperatures for a comprehensive seasonal picture of Holocene Arctic climate variability. Polygonal ice wedges are a widespread permafrost feature in the Arctic tundra lowlands. Ice wedges form by the repeated filling of thermal contraction cracks with snow melt water, which quickly refreezes at subzero ground temperatures and forms ice veins. As the seasonality of frost cracking and infill is generally related to winter and spring, respectively, the isotopic composition of wedge ice is indicative of past climate conditions during the annual cold season (DJFMAM, hereafter referred to as winter). δ18O of ice is interpreted as proxy for regional surface air temperature. AMS radiocarbon dating of organic remains in ice-wedge samples provides age information to generate chronologies for single ice wedges as well as regionally stacked records with an up to centennial resolution. In this contribution we seek to summarize Holocene ice-wedge δ18O based temperature information from the Northeast Siberian Arctic. We strongly focus on own work in the Laptev Sea region but consider as well literature data from other regional study sites. We consider the stable-isotope composition of wedge ice, ice-wedge dating and chronological

  8. Latest Pleistocene Sediment Wedge on the New Jersey Outer Continental Shelf - Forced Regressive Paleo-Hudson Delta?

    NASA Astrophysics Data System (ADS)

    Santra, M.; Goff, J. A.; Steel, R. J.

    2011-12-01

    The offlapping sediment wedge on the outer shelf off New Jersey that overlies the regional reflector R-horizon shows many of the characteristic features of a progradational succession deposited during falling sea level (forced regression). This interpretation is consistent with the estimated latest Pleistocene age of the wedge - a well-established period of large-scale eustatic sea level fall. The sediment wedge occupies the outer shelf of New Jersey south of the Hudson Shelf Valley, extending down to the shelf edge. The sediment wedge appears to be strongly strike-oriented. The absence of any record of time-equivalent fluvial/distributary channels on the proximal part of the sediment wedge led some previous workers to the interpretation that the wedge was a product of redistribution of sediment on the shelf rather than a deltaic feature supplied by a fluvial source. The absence of fluvial and coastal plain deposits capping the proximal end of the wedge is actually a characteristic feature of forced regressive deposits and does not preclude a fluvial source for the sediments constituting the wedge. Reinterpretation of high-resolution (1-12 kHz), deep-towed and hull-mounted CHIRP seismic data collected on the New Jersey outer shelf in 2001, 2002 and 2006 shows possible terminal distributary channel deposits and mass transport deposits preserved in the distal part of the wedge that have not been described previously. These channel-like features are restricted in their distribution and their preservation in the sedimentary record is possibly due to punctuated sea-level rise within the overall falling trajectory of sea level that preceded the last glacial maximum (LGM). The presence of these channels and the mass transport complexes point to a direct fluvial feeder, which supplied the sediments to build the sediment wedge on New Jersey outer continental shelf. Detailed mapping of the sediment wedge using the CHIRP data shows that the sediment wedge is composed of

  9. 21 CFR 884.5200 - Hemorrhoid prevention pressure wedge.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hemorrhoid prevention pressure wedge. 884.5200... Devices § 884.5200 Hemorrhoid prevention pressure wedge. (a) Identification. A hemorrhoid prevention pressure wedge provides mechanical support to the perianal region during the labor and delivery...

  10. 21 CFR 884.5200 - Hemorrhoid prevention pressure wedge.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hemorrhoid prevention pressure wedge. 884.5200... Devices § 884.5200 Hemorrhoid prevention pressure wedge. (a) Identification. A hemorrhoid prevention pressure wedge provides mechanical support to the perianal region during the labor and delivery...

  11. 49 CFR 215.113 - Defective plain bearing wedge.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Defective plain bearing wedge. 215.113 Section 215... Suspension System § 215.113 Defective plain bearing wedge. A railroad may not place or continue in service a car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not...

  12. 49 CFR 215.113 - Defective plain bearing wedge.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Defective plain bearing wedge. 215.113 Section 215... Suspension System § 215.113 Defective plain bearing wedge. A railroad may not place or continue in service a car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not...

  13. 49 CFR 215.113 - Defective plain bearing wedge.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Defective plain bearing wedge. 215.113 Section 215... Suspension System § 215.113 Defective plain bearing wedge. A railroad may not place or continue in service a car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not...

  14. 49 CFR 215.113 - Defective plain bearing wedge.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Defective plain bearing wedge. 215.113 Section 215... Suspension System § 215.113 Defective plain bearing wedge. A railroad may not place or continue in service a car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not...

  15. 49 CFR 215.113 - Defective plain bearing wedge.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Defective plain bearing wedge. 215.113 Section 215... Suspension System § 215.113 Defective plain bearing wedge. A railroad may not place or continue in service a car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not...

  16. Climate adaptation wedges: a case study of premium wine in the western United States

    SciTech Connect

    Diffenbaugh, Noah; White, Michael A; Jones, Gregory V; Ashfaq, Moetasim

    2011-01-01

    Design and implementation of effective climate change adaptation activities requires quantitative assessment of the impacts that are likely to occur without adaptation, as well as the fraction of impact that can be avoided through each activity. Here we present a quantitative framework inspired by the greenhouse gas stabilization wedges of Pacala and Socolow. In our proposed framework, the damage avoided by each adaptation activity creates an 'adaptation wedge' relative to the loss that would occur without that adaptation activity. We use premium winegrape suitability in the western United States as an illustrative case study, focusing on the near-term period that covers the years 2000 39. We find that the projected warming over this period results in the loss of suitable winegrape area throughout much of California, including most counties in the high-value North Coast and Central Coast regions. However, in quantifying adaptation wedges for individual high-value counties, we find that a large adaptation wedge can be captured by increasing the severe heat tolerance, including elimination of the 50% loss projected by the end of the 2030 9 period in the North Coast region, and reduction of the projected loss in the Central Coast region from 30% to less than 15%. Increased severe heat tolerance can capture an even larger adaptation wedge in the Pacific Northwest, including conversion of a projected loss of more than 30% in the Columbia Valley region of Washington to a projected gain of more than 150%. We also find that warming projected over the near-term decades has the potential to alter the quality of winegrapes produced in the western US, and we discuss potential actions that could create adaptation wedges given these potential changes in quality. While the present effort represents an initial exploration of one aspect of one industry, the climate adaptation wedge framework could be used to quantitatively evaluate the opportunities and limits of climate adaptation

  17. Measured Hydrologic Storage Characteristics of Three Major Ice Wedge Polygon Types, Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Chamberlain, A. J.; Liljedahl, A.; Wilson, C. J.; Cable, W.; Romanovsky, V. E.

    2014-12-01

    Model simulations have suggested that the hydrologic fluxes and stores of Arctic wetlands are constrained by the micro-topographical features of ice wedge polygons, which are abundant in lowland tundra landscapes. Recently observed changes in ice wedge polygon landscapes - in particular, ice wedge degradation and trough formation - emphasize the need to better understand how differing ice wedge polygon morphologies affect the larger hydrologic system. Here we present three seasons of measured end-of-winter snow accumulation, continuous soil moisture and water table elevations, and repeated frost table mapping. Together, these describe the hydrologic characteristics of three main ice wedge polygon types: low centered polygons with limited trough development (representative of a ~500 year old vegetated drained thaw lake basin), and low- and high-centered polygons with well-defined troughs. Dramatic spatiotemporal variability exists both between polygon types and between the features of an individual polygon (e.g. troughs, centers, rims). Landscape-scale end-of-winter snow water equivalent is similar between polygon types, while the sub-polygon scale distribution of the surface water differs, both as snow and as ponded water. Some sub-polygon features appear buffered against large variations in water levels, while others display periods of prolonged recessions and large responses to rain events. Frost table elevations in general mimic the ground surface topography, but with spatiotemporal variability in thaw rate. The studied thaw seasons represented above long-term average rainfall, and in 2014, record high June precipitation. Differing ice wedge polygon types express dramatically different local hydrology, despite nearly identical climate forcing and landscape-scale snow accumulation, making ice wedge polygons an important component when describing the Arctic water, nutrient and energy system.

  18. Experimental study on the water impact of a symmetrical wedge

    NASA Astrophysics Data System (ADS)

    Yettou, El-Mahdi; Desrochers, Alain; Champoux, Yvan

    2006-01-01

    In this paper, we report the results of our experimental investigation of the pressure distribution on a free-falling wedge upon entering water. Parameters such as the drop height, the deadrise angle and the mass of the wedge are related to the water pressure on the wedge and its dynamic behavior. Existing models that assumed a constant water-entry velocity of the wedge are compared with experimental data. In order to take into account the inherent variation in the velocity of a free-falling wedge, a combination of two models are proposed. This method gives an adequate approximation of the maximum pressures measured.

  19. Process Based Explanations for Correlations Between the Structural and Seismic Segmentation of the Cascadia Subduction Wedge

    NASA Astrophysics Data System (ADS)

    Fuller, C. W.; Brandon, M. T.; Willett, S. D.

    2006-12-01

    Variations in the geological and geophysical characteristics of the Cascadia subduction wedge, the region between the trench and arc, result in along-strike wedge segmentation. We focus on explaining the large-scale structural segmentation and how processes causing this segmentation influence segmentation with respect to the seismic behavior of the wedge and subduction thrust. The relationships we develop illustrate the fundamental interplay of processes controlling long-term structure and short-term seismic behavior. Our conclusions are based on the results of numerical models designed to simulate the growth and evolution of the Cascadia subduction wedge through the accretion of a thin layer of sediment to the basaltic Coast Range Terrane (CRT) of the Cascadia margin. Two aspects of wedge structural segmentation are of interest: (1) segmentation with respect to the location or absence of large, continental shelf, forearc basins, and (2) segmentation with respect to the Coastal Range (CR) structural high. Our models illustrate that the form of the submarine portion of the Cascadia wedge, including the basins or lack thereof, is a consequence of the frictional behavior of this region of wedge, subduction thrust strength, wedge strength, and dip thrust. We propose that basin segments have stronger wedge material, a weaker thrust, or a steeper thrust than basin free segments. The presence of basins is significant because they stabilize the margin and prevent subduction and accretion related deformation. This stabilization allows the thrust to preferentially support thermally induced, fluid overpressures and undergo fault healing thus increasing the likelihood of large coseismic slip within basin segments. While no historical earthquake data supporting this argument exists for Cascadia, such behavior has been observed in many margins (Song and Simons, 2003; Wells et al., 2003). It is reasonable to assume that large earthquakes in Cascadia will have the same association

  20. Radiation pressure on a dielectric wedge.

    PubMed

    Mansuripur, Masud; Zakharian, Armis; Moloney, Jerome

    2005-03-21

    The force of electromagnetic radiation on a dielectric medium may be derived by a direct application of the Lorentz law of classical electrodynamics. While the light's electric field acts upon the (induced) bound charges in the medium, its magnetic field exerts a force on the bound currents. We use the example of a wedge-shaped solid dielectric, immersed in a transparent liquid and illuminated at Brewster's angle, to demonstrate that the linear momentum of the electromagnetic field within dielectrics has neither the Minkowski nor the Abraham form; rather, the correct expression for momentum density has equal contributions from both. The time rate of change of the incident momentum thus expressed is equal to the force exerted on the wedge plus that experienced by the surrounding liquid.

  1. Maladaptively high and low openness: the case for experiential permeability.

    PubMed

    Piedmont, Ralph L; Sherman, Martin F; Sherman, Nancy C

    2012-12-01

    The domain of Openness within the Five-Factor Model (FFM) has received inconsistent support as a source for maladaptive personality functioning, at least when the latter is confined to the disorders of personality included within the American Psychiatric Association's (APA) Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR; APA, ). However, an advantage of the FFM relative to the DSM-IV-TR is that the former was developed to provide a reasonably comprehensive description of general personality structure. Rather than suggest that the FFM is inadequate because the DSM-IV-TR lacks much representation of Openness, it might be just as reasonable to suggest that the DSM-IV-TR is inadequate because it lacks an adequate representation of maladaptive variants of both high and low Openness. This article discusses the development and validation of a measure of these maladaptive variants, the Experiential Permeability Inventory.

  2. Wedge assembly for electrical transformer component spacing

    DOEpatents

    Baggett, Franklin E.; Cage, W. Franklin

    1991-01-01

    A wedge assembly that is easily inserted between two surfaces to be supported thereby, and thereafter expanded to produce a selected spacing between those surfaces. This wedge assembly has two outer members that are substantially identical except that they are mirror images of each other. Oppositely directed faces of these of these outer members are substantially parallel for the purpose of contacting the surfaces to be separated. The outer faces of these outer members that are directed toward each other are tapered so as to contact a center member having complementary tapers on both faces. A washer member is provided to contact a common end of the outer members, and a bolt member penetrates this washer and is threadably received in a receptor of the center member. As the bolt member is threaded into the center member, the center member is drawn further into the gap between the outer members and thereby separates these outer members to contact the surfaces to be separated. In the preferred embodiment, the contacting surfaces of the outer member and the center member are provided with guide elements. The wedge assembly is described for use in separating the secondary windings from the laminations of an electrical power transformer.

  3. Interior impedance wedge diffraction with surface waves

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Griesser, Timothy

    1988-01-01

    The exact impedance wedge solution is evaluated asymptotically using the method of steepest descents for plane wave illumination at normal incidence. Uniform but different impedances on each face are considered for both soft and hard polarizations. The asymptotic solution isolates the incident, singly reflected, multiply reflected, diffracted, and surface wave fields. Multiply reflected fields of any order are permitted. The multiply reflected fields from the exact solution are written as ratios of auxiliary Maliuzhinets functions, whereas a geometrical analysis gives the reflected fields as products of reflection coefficients. These two representations are shown to be identical in magnitude, phase and the angular range over which they exist. The diffracted field includes four Fresnel transition functions as in the perfect conductor case, and the expressions for the appropriate discontinuities at the shadow boundaries are presented. The surface wave exists over a finite angular range and only for certain surface impedances. A surface wave transition field is included to retain continuity. Computations are presented for interior wedge diffractions although the formulation is valid for both exterior and interior wedges.

  4. An Experimental Investigation of Transonic Flow Past Two-Dimensional Wedge and Circular-Arc Sections Using A Mach-Zehnder Interferometer

    NASA Technical Reports Server (NTRS)

    Bryson, Arthur Earl, Jr

    1952-01-01

    Report presents the results of interferometer measurements of the flow field near two-dimensional wedge and circular-arc sections of zero angle of attack at high-subsonic and low-supersonic velocities. Both subsonic flow with local supersonic zone and supersonic flow with detached shock wave have been investigated. Pressure distributions and drag coefficients as a function of Mach number have been obtained. The wedge data are compared with the theoretical work on flow past wedge sections of Guderley and Yoshihara, Vincenti and Wagner, and Cole. Pressure distributions and drag coefficients for the wedge and circular-arc sections are presented throughout the entire transonic range of velocities.

  5. Effect of shockwave curvature on run distance observed with a modified wedge test

    NASA Astrophysics Data System (ADS)

    Lee, Richard; Dorgan, Robert J.; Sutherland, Gerrit; Benedetta, Ashley; Milby, Christopher

    2012-03-01

    The effect of wave curvature on shock initiation in PBXN-110 was investigated using a modified wedge test configuration. Various widths of PBXN-110 donor slabs were used to define the shockwave curvature introduced to wedge samples of the same explosive. The donor slabs were initiated with line-wave generators so that the shock from the donor would be the same shape, magnitude and duration across the entire input surface of the wedge. The shock parameters were varied for a given donor with PMMA spacers placed between the donor and the wedge sample. A high-speed electronic framing camera was used to observe where initiation occurred along the face of the wedge. Initiation always occurred at the center of the shock front instead of along the sides like that reported by others using a much smaller test format. Results were compared to CTH calculations to indicate if there were effects associated with highly curved shock fronts that could not be adequately predicted. The run distance predicted in CTH for a 50.8 mm wide donor slab (low curvature) compared favorably with experimental results. However, results from thinner donor slabs (higher curvature) indicate a more sensitive behavior than the simulations predicted.

  6. Wedge hybrid plasmonic THz waveguide with long propagation length and ultra-small deep-subwavelength mode area

    PubMed Central

    Gui, Chengcheng; Wang, Jian

    2015-01-01

    We present a novel design of wedge hybrid plasmonic terahertz (THz) waveguide consisting of a silicon (Si) nanowire cylinder above a triangular gold wedge with surrounded high-density polyethylene as cladding. It features long propagation length and ultra-small deep-subwavelength mode confinement. The mode properties of wedge hybrid plasmonic THz waveguide are comprehensively characterized in terms of propagation length (L), normalized mode area (Aeff /A0), figure of merit (FoM), and chromatic dispersion (D). The designed wedge hybrid plasmonic THz waveguide enables an ultra-small deep-subwavelength mode area which is more than one-order of magnitude smaller compared to previous rectangular one. When choosing the diameter of Si nanowire cylinder, a smaller diameter (e.g. 10 μm) is preferred to achieve longer L and higher FoM, while a larger diameter (e.g. 60 μm) is favorable to obtain smaller Aeff /A0 and higher FoM. We further study the impacts of possible practical fabrication errors on the mode properties. The simulated results of propagation length and normalized mode area show that the proposed wedge hybrid plasmonic THz waveguide is tolerant to practical fabrication errors in geometry parameters such as misalignment in the horizontal direction, variation of wedge tip angle, and variation of wedge tip curvature radius. PMID:26155782

  7. Separation over a flat plate-wedge configuration at oceanic Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Campbell, D. R.

    1973-01-01

    An experimental study of flow over a two-dimensional flat plate-wedge configuration is presented. The investigation encompasses a range of Reynolds numbers characteristics of conditions encountered by deep submersible oceanic vehicles. Flow separation, similar to that found on high speed aircraft control surfaces, is reported and discussed in light of the laminar or transitional nature of the separated shear layer. As discovered in previous high Mach number studies of plate-wedge or ramp configurations, the dependency of the size of the separated region on free stream Reynolds number is reversed for laminar and transitional types of flow separation.

  8. Investigation of turbulent wedges generated by different single surface roughness elements

    NASA Astrophysics Data System (ADS)

    Traphan, Dominik; Meinlschmidt, Peter; Lutz, Otto; Peinke, Joachim; Gülker, Gerd

    2013-11-01

    It is known that small faults on rotor blades of wind turbines can cause significant power loss. In order to better understand the governing physical effects, in this experimental study, the formation of a turbulent wedge over a flat plate induced by single surface roughness elements is under investigation. The experiments are performed at different ambient pressure gradients, thus allowing conclusions about the formation of a turbulent wedge over an airfoil. With respect to typical initial faults on operating airfoils, the roughness elements are modified in both size and shape (raised or recessed). None intrusive experimental methods, such as stereoscopic PIV and LDA, enable investigations based on temporally and spatially highly resolved velocity measurements. In this way, a spectral analysis of the turbulent boundary layer is performed and differences in coherent structures within the wedge are identified. These findings are correlated with global measurements of the wedge carried out by infrared thermography. This correlation aims to enable distinguishing the cause and main properties of a turbulent wedge by the easy applicable method of infrared thermography, which is of practical relevance in the field of condition monitoring of wind turbines.

  9. Effect of Shockwave Curvature on Run Distance Observed with a Modified Wedge Test

    NASA Astrophysics Data System (ADS)

    Lee, Richard; Dorgan, Robert; Sutherland, Gerrit; Benedetta, Ashley; Milby, Christopher

    2011-06-01

    The effect of wave curvature on shock initiation in PBXN-110 was investigated using a modified wedge test configuration. Various thicknesses of PBXN-110 donor slabs were used to define the shockwave curvature introduced to wedge samples of the same explosive. The donor slabs were initiated with line-wave generators so that the introduced shock would be the same shape, magnitude and duration across the entire input surface of the wedge. The shock parameters were varied for a given donor thickness via different widths of PMMA spacers placed between the donor and the wedge. A framing camera was used to observe where initiation occurred along the face of the wedge. Initiation always occurred at the center of the shock front instead of the sides like that reported by others using a much smaller test format. Results were compared to CTH calculations to indicate if there were effects associated with highly curved shock fronts that could not be adequately predicted. The run distance predicted in CTH for a 50.8 mm thick donor slab (low curvature) compared favorably with experimental results. However, results from thinner donor slabs (higher curvature) indicate a more sensitive behavior than the simulations predicted.

  10. Dying Flow Bursts as Generators of the Substorm Current Wedge

    NASA Astrophysics Data System (ADS)

    Haerendel, G.

    2015-12-01

    Many theories or conjectures exist on the driver of the substorm current wedge, e.g. rerouting of the tail current, current disruption, flow braking, vortex formation, and current sheet collapse. Magnitude, spatial scale, and temporal development of the related magnetic perturbations suggest that the generator is related to the interaction of the flow bursts with the dipolar magnetosphere after onset of reconnection in the near-Earth tail. The question remains whether it is the flow energy that feeds the wedge current or the internal energy of the arriving plasma. In this presentation I argue for the latter. The current generation is attributed to the force exerted by the dipolarized magnetic field of the flow bursts on the preceding layer of high-beta plasma after flow braking. The generator current is the grad-B current at the outer boundary of the compressed high-beta plasma layers. It needs the sequential arrival of several flow bursts to account for duration and magnitude of the ionospheric closure current.

  11. Dying Flow Bursts as Generators of the Substorm Current Wedge

    NASA Astrophysics Data System (ADS)

    Haerendel, Gerhard

    2016-07-01

    Many theories or conjectures exist on the driver of the substorm current wedge, e.g. rerouting of the tail current, current disruption, flow braking, vortex formation, and current sheet collapse. Magnitude, spatial scale, and temporal development of the related magnetic perturbations suggest that the generator is related to the interaction of the flow bursts with the dipolar magnetosphere after onset of reconnection in the near-Earth tail. The question remains whether it is the flow energy that feeds the wedge current or the internal energy of the arriving plasma. In this presentation I argue for the latter. The current generation is attributed to the force exerted by the dipolarized magnetic field of the flow bursts on the preceding layer of high-beta plasma after flow braking. The generator current is the grad-B current at the outer boundary of the compressed high-beta plasma layers. It needs the sequential arrival of several flow bursts to account for duration and magnitude of the ionospheric closure current.

  12. Open tube guideway for high speed air cushioned vehicles

    NASA Technical Reports Server (NTRS)

    Goering, R. S. (Inventor)

    1974-01-01

    This invention is a tubular shaped guideway for high-speed air-cushioned supported vehicles. The tubular guideway is split and separated such that the sides of the guideway are open. The upper portion of the tubular guideway is supported above the lower portion by truss-like structural members. The lower portion of the tubular guideway may be supported by the terrain over which the vehicle travels, on pedestals or some similar structure.

  13. NASA/GE Collaboration on Open Rotors - High Speed Testing

    NASA Technical Reports Server (NTRS)

    VanZante, Dale E.

    2011-01-01

    A low-noise open rotor system is being tested in collaboration with General Electric and CFM International, a 50/50 joint company between Snecmaand GE. Candidate technologies for lower noise will be investigated as well as installation effects such as pylon integration. Current test status for the 8x6 SWT high speed testing is presented as well as future scheduled testing which includes the FAA/CLEEN test entry. The tunnel blockage and propeller thrust calibration configurations are shown.

  14. NGC 1252: a high altitude, metal poor open cluster remnant

    NASA Astrophysics Data System (ADS)

    de la Fuente Marcos, R.; de la Fuente Marcos, C.; Moni Bidin, C.; Carraro, G.; Costa, E.

    2013-09-01

    If stars form in clusters but most stars belong to the field, understanding the details of the transition from the former to the latter is imperative to explain the observational properties of the field. Aging open clusters are one of the sources of field stars. The disruption rate of open clusters slows down with age but, as an object gets older, the distinction between the remaining cluster or open cluster remnant (OCR) and the surrounding field becomes less and less obvious. As a result, finding good OCR candidates or confirming the OCR nature of some of the best candidates still remain elusive. One of these objects is NGC 1252, a scattered group of about 20 stars in Horologium. Here we use new wide-field photometry in the UBVI passbands, proper motions from the Yale/San Juan SPM 4.0 catalogue and high-resolution spectroscopy concurrently with results from N-body simulations to decipher NGC 1252's enigmatic character. Spectroscopy shows that most of the brightest stars in the studied area are chemically, kinematically and spatially unrelated to each other. However, after analysing proper motions, we find one relevant kinematic group. This sparse object is relatively close (˜1 kpc), metal poor and is probably not only one of the oldest clusters (3 Gyr) within 1.5 kpc from the Sun but also one of the clusters located farthest from the disc, at an altitude of nearly -900 pc. That makes NGC 1252 the first open cluster that can be truly considered a high Galactic altitude OCR: an unusual object that may hint at a star formation event induced on a high Galactic altitude gas cloud. We also conclude that the variable TW Horologii and the blue straggler candidate HD 20286 are unlikely to be part of NGC 1252. NGC 1252 17 is identified as an unrelated, Population II cannonball star moving at about 400 km s-1.

  15. Wedge energy bands of monolayer black phosphorus: a first-principles study

    NASA Astrophysics Data System (ADS)

    Park, Minwoo; Bae, Hyeonhu; Lee, Seunghan; Yang, Li; Lee, Hoonkyung

    2016-08-01

    On the basis of first-principles calculations, we present intriguing electronic properties of halogen-striped functionalized monolayer black phosphorus. The halogen-striped monolayer black phosphorus is found to have a wedge energy band with the energy-momentum relation of E\\propto {{p}y} when the stripe–stripe distance is smaller than ~40 Å. Our tight-binding study shows that the wedge energy band occurs when 2-atom basis 1D lattices are periodically repeated aligned with each other in a 2D lattice. We also discuss the possible applications of this wedge energy band in electron supercollimation with high mobility or severely anisotropic electronic transport, which can be used for the development of optics-like nano-electronics.

  16. Wedge energy bands of monolayer black phosphorus: a first-principles study

    NASA Astrophysics Data System (ADS)

    Park, Minwoo; Bae, Hyeonhu; Lee, Seunghan; Yang, Li; Lee, Hoonkyung

    2016-08-01

    On the basis of first-principles calculations, we present intriguing electronic properties of halogen-striped functionalized monolayer black phosphorus. The halogen-striped monolayer black phosphorus is found to have a wedge energy band with the energy-momentum relation of E\\propto {{p}y} when the stripe-stripe distance is smaller than ~40 Å. Our tight-binding study shows that the wedge energy band occurs when 2-atom basis 1D lattices are periodically repeated aligned with each other in a 2D lattice. We also discuss the possible applications of this wedge energy band in electron supercollimation with high mobility or severely anisotropic electronic transport, which can be used for the development of optics-like nano-electronics.

  17. Wedge energy bands of monolayer black phosphorus: a first-principles study.

    PubMed

    Park, Minwoo; Bae, Hyeonhu; Lee, Seunghan; Yang, Li; Lee, Hoonkyung

    2016-08-01

    On the basis of first-principles calculations, we present intriguing electronic properties of halogen-striped functionalized monolayer black phosphorus. The halogen-striped monolayer black phosphorus is found to have a wedge energy band with the energy-momentum relation of [Formula: see text] when the stripe-stripe distance is smaller than ~40 Å. Our tight-binding study shows that the wedge energy band occurs when 2-atom basis 1D lattices are periodically repeated aligned with each other in a 2D lattice. We also discuss the possible applications of this wedge energy band in electron supercollimation with high mobility or severely anisotropic electronic transport, which can be used for the development of optics-like nano-electronics. PMID:27299467

  18. Predicting Run Distances for a Modified Wedge Test

    NASA Astrophysics Data System (ADS)

    Dorgan, Robert J.; Lee, Richard; Sutherland, Gerrit

    2012-03-01

    Simulations were used to aid in the development of a modified wedge test (MWT). This explosive sensitivity experiment allows the shockwave curvature to be defined in order to investigate the effect of combined shock-shear loading on sensitivity. Various widths of PBXN-110 donor slabs were used to define the shockwave curvature introduced to wedge samples of the same explosive. The donor slabs were initiated with a linewave generator and a Detasheet booster, and the shock wave was attenuated using a slab of PMMA. In developing simulations for these three material experiments, calibrations of the PBXN-110 ignition and growth model and of the PMMA constitutive model were investigated in order to choose between several models found in the literature. A calibration shot from the MWT was also used to demonstrate the appropriateness of the models selected. Experimental results were compared to CTH calculations to indicate if there were effects associated with highly curved shock fronts that could not be adequately predicted. The run distances predicted in CTH for the thicker donor slab compare very favorably with the actual experiments; however, for thinner donor slabs, the actual experimental results seem to suggest a more sensitive behavior than the simulations are able to capture.

  19. Predicting Run Distances for a Modified Wedge Test

    NASA Astrophysics Data System (ADS)

    Dorgan, Robert; Lee, Richard; Sutherland, Gerrit

    2011-06-01

    Simulations were used to aid in the development of a modified wedge test (MWT). This explosive sensitivity experiment allows the shockwave curvature to be defined in order to investigate the effect of combined shock-shear loading on sensitivity. Various widths of PBXN-110 donor slabs were used to define the shockwave curvature introduced to wedge samples of the same explosive. The donor slabs were initiated with a linewave generator and a Detasheet booster, and the shock wave was attenuated using a slab of PMMA. In developing simulations for these three material experiments, calibrations of the PBXN-110 ignition and growth model and of the PMMA constitutive model were investigated in order to choose between several models found in the literature. A calibration shot from the MWT was also used to demonstrate the appropriateness of the models selected. Experimental results were compared to CTH calculations to indicate if there were effects associated with highly curved shock fronts that could not be adequately predicted. The run distances predicted in CTH for the thicker donor slab compare very favorably with the actual experiments; however, for thinner donor slabs, the actual experimental results seem to suggest a more sensitive behavior than the simulations are able to capture. DISTRIBUTION A. Approved for public release, distribution unlimited. (96ABW-2011-0053)

  20. An automated optical wedge calibrator for Dobson ozone spectrophotometers

    NASA Technical Reports Server (NTRS)

    Evans, R. D.; Komhyr, W. D.; Grass, R. D.

    1994-01-01

    The Dobson ozone spectrophotometer measures the difference of intensity between selected wavelengths in the ultraviolet. The method uses an optical attenuator (the 'Wedge') in this measurement. The knowledge of the relationship of the wedge position to the attenuation is critical to the correct calculation of ozone from the measurement. The procedure to determine this relationship is time-consuming, and requires a highly skilled person to perform it correctly. The relationship has been found to change with time. For reliable ozone values, the procedure should be done on a Dobson instrument at regular intervals. Due to the skill and time necessary to perform this procedure, many instruments have gone as long as 15 years between procedures. This article describes an apparatus that performs the procedure under computer control, and is adaptable to the majority of existing Dobson instruments. Part of the apparatus is usable for normal operation of the Dobson instrument, and would allow computer collection of the data and real-time ozone measurements.

  1. The wedge bias in reionization 21-cm power spectrum measurements

    NASA Astrophysics Data System (ADS)

    Jensen, Hannes; Majumdar, Suman; Mellema, Garrelt; Lidz, Adam; Iliev, Ilian T.; Dixon, Keri L.

    2016-02-01

    A proposed method for dealing with foreground emission in upcoming 21-cm observations from the epoch of reionization is to limit observations to an uncontaminated window in Fourier space. Foreground emission can be avoided in this way, since it is limited to a wedge-shaped region in k∥, k⊥ space. However, the power spectrum is anisotropic owing to redshift-space distortions from peculiar velocities. Consequently, the 21-cm power spectrum measured in the foreground avoidance window - which samples only a limited range of angles close to the line-of-sight direction - differs from the full redshift-space spherically averaged power spectrum which requires an average over all angles. In this paper, we calculate the magnitude of this `wedge bias' for the first time. We find that the bias amplifies the difference between the real-space and redshift-space power spectra. The bias is strongest at high redshifts, where measurements using foreground avoidance will overestimate the redshift-space power spectrum by around 100 per cent, possibly obscuring the distinctive rise and fall signature that is anticipated for the spherically averaged 21-cm power spectrum. In the later stages of reionization, the bias becomes negative, and smaller in magnitude (≲20 per cent).

  2. Multi-gap high impedance plasma opening switch

    DOEpatents

    Mason, R.J.

    1996-10-22

    A high impedance plasma opening switch having an anode and a cathode and at least one additional electrode placed between the anode and cathode is disclosed. The presence of the additional electrodes leads to the creation of additional plasma gaps which are in series, increasing the net impedance of the switch. An equivalent effect can be obtained by using two or more conventional plasma switches with their plasma gaps wired in series. Higher impedance switches can provide high current and voltage to higher impedance loads such as plasma radiation sources. 12 figs.

  3. Multi-gap high impedance plasma opening switch

    DOEpatents

    Mason, Rodney J.

    1996-01-01

    A high impedance plasma opening switch having an anode and a cathode and at least one additional electrode placed between the anode and cathode. The presence of the additional electrodes leads to the creation of additional plasma gaps which are in series, increasing the net impedance of the switch. An equivalent effect can be obtained by using two or more conventional plasma switches with their plasma gaps wired in series. Higher impedance switches can provide high current and voltage to higher impedance loads such as plasma radiation sources.

  4. Knee abduction angular impulses during prolonged running with wedged insoles.

    PubMed

    Lewinson, Ryan T; Worobets, Jay T; Stefanyshyn, Darren J

    2013-07-01

    Wedged insoles may produce immediate effects on knee abduction angular impulses during running; however, it is currently not known whether these knee abduction angular impulse magnitudes are maintained throughout a run when fatigue sets in. If changes occur, this could affect the clinical utility of wedged insoles in treating conditions such as patellofemoral pain. Thus, the purpose of this study was to determine whether knee abduction angular impulses are altered during a prolonged run with wedged insoles. It was hypothesized that knee abduction angular impulses would be reduced following a prolonged run with wedged insoles. Nine healthy runners participated. Runners were randomly assigned to either a 6-mm medial wedge condition or a 6-mm lateral wedge condition and then ran continuously overground for 30 min. Knee abduction angular impulses were quantified at 0 and 30 min using a gait analysis procedure. After 2 days, participants returned to perform the same test but with the other wedge type. Two-way repeated-measures analysis of variance was used to evaluate main effects of wedge condition and time and interactions between wedge condition and time (α = 0.05). Paired t-tests were used for post hoc analysis (α = 0.01). No interaction effects (p = 0.958) were found, and knee abduction angular impulses were not significantly different over time (p = 0.384). Lateral wedge conditions produced lesser knee abduction angular impulses than medial conditions at 0 min (difference of 2.79 N m s, p = 0.006) and at 30 min (difference of 2.76 N m s, p < 0.001). It is concluded that significant knee abduction angular impulse changes within wedge conditions do not occur during a 30-min run. Additionally, knee abduction angular impulse differences between wedge conditions are maintained during a 30-min run.

  5. Impingement of water droplets on wedges and double-wedge airfoils at supersonic speeds

    NASA Technical Reports Server (NTRS)

    Serafini, John S

    1954-01-01

    An analytical solution has been obtained for the equations of motion of water droplets impinging on a wedge in a two-dimensional supersonic flow field with a shock wave attached to the wedge. The closed-form solution yields analytical expressions for the equation of the droplet trajectory, the local rate of impingement and the impingement velocity at any point on the wedge surface, and the total rate of impingement. The analytical expressions are utilized to determine the impingement on the forward surfaces of diamond airfoils in supersonic flow fields with attached shock waves. The results presented include the following conditions: droplet diameters from 2 to 100 microns, pressure altitudes from sea level to 30,000 feet, free-stream static temperatures from 420 degrees r, free stream Mach numbers from 1.1 to 2.0, semiapex angles for the wedge from 1.14 degrees to 7.97 degrees, thickness-to-chord ratios for the diamond airfoil from 0.02 to 0.14, chord lengths from 1 to 20 feet, and angles of attack from zero to the inverse tangent of the airfoil thickness-to-chord ratio.

  6. Molecular depth profiling by wedged crater beveling.

    PubMed

    Mao, Dan; Lu, Caiyan; Winograd, Nicholas; Wucher, Andreas

    2011-08-15

    Time-of-flight secondary ion mass spectrometry and atomic force microscopy are employed to characterize a wedge-shaped crater eroded by a 40-keV C(60)(+) cluster ion beam on an organic film of Irganox 1010 doped with Irganox 3114 delta layers. From an examination of the resulting surface, the information about depth resolution, topography, and erosion rate can be obtained as a function of crater depth for every depth in a single experiment. It is shown that when measurements are performed at liquid nitrogen temperature, a constant erosion rate and reduced bombardment induced surface roughness is observed. At room temperature, however, the erosion rate drops by ∼(1)/(3) during the removal of the 400 nm Irganox film and the roughness gradually increased to from 1 nm to ∼4 nm. From SIMS lateral images of the beveled crater and AFM topography results, depth resolution was further improved by employing glancing angles of incidence and lower primary ion beam energy. Sub-10 nm depth resolution was observed under the optimized conditions on a routine basis. In general, we show that the wedge-crater beveling is an important tool for elucidating the factors that are important for molecular depth profiling experiments.

  7. Experimental and numerical investigations on melamine wedges.

    PubMed

    Schneider, S

    2008-09-01

    Melamine wedges are often used as acoustic lining material for anechoic chambers. It was proposed here to study the effects of the mounting conditions on the acoustic properties of the melamine wedges used in the large anechoic chamber at the LMA. The results of the impedance tube measurements carried out show that the mounting conditions must be taken into account when assessing the quality of an acoustic lining. As it can be difficult to simulate these mounting conditions in impedance tube experiments, a numerical method was developed, which can be used to complete the experiments or for parametric studies. By combining the finite and the boundary element method, it is possible to investigate acoustic linings with almost no restrictions as to the geometry, material behavior, or mounting conditions. The numerical method presented here was used to study the acoustic properties of the acoustic lining installed in the anechoic chamber at the LMA. Further experiments showed that the behavior of the melamine foam is anisotropic. Numerical simulations showed that this anisotropy can be used to advantage when designing an acoustic lining.

  8. Mid-Calcaneal Length After Evans Calcaneal Osteotomy: A Retrospective Comparison of Wedge Locking Plates and Tricortical Allograft Wedges.

    PubMed

    Protzman, Nicole M; Wobst, Garrett M; Storts, Eric C; Mulhern, Jennifer L; McCarroll, Raymond E; Brigido, Stephen A

    2015-01-01

    Evans calcaneal osteotomy remains a cornerstone in the correction of the flexible flatfoot. Although multiple techniques have been used to maintain the length of the lateral column, a low profile wedge locking plate was recently introduced as an alternative to the traditional tricortical allograft wedge. We hypothesized that the wedge locking plate would better maintain the mid-calcaneal length compared with the tricortical allograft wedge. To test this hypothesis, after Evans osteotomy, the mid-calcaneal length was measured in the immediate postoperative period and again at 3 and 6 months. A total of 24 patients met the inclusion criteria. The mean patient age was 48.1 years (range 11 to 66). Of the 24 patients, 9 (37.5%) were treated with a tricortical allograft wedge and 15 (62.5%) with a wedge locking plate. At 3 months postoperatively, the mean decrease in mid-calcaneal length was similar for the tricortical allograft wedge group (1.3 ± 1.9 mm) and the wedge locking plate group (0.5 ± 0.9 mm, p = .275). At 6 months postoperatively, however, the mean decrease in mid-calcaneal length was greater for the tricortical allograft wedge group (2.8 ± 1.7 mm) than for the wedge locking plate group (0.6 ± 0.7 mm, p = .004). The 2 groups demonstrated a similar incidence of dorsally displaced distal calcaneal fragments throughout the study endpoint (p ≥ .052). These results suggest that the wedge locking plate better maintains the mid-calcaneal length over time compared with the tricortical allograft wedge.

  9. The Gray Institute 'open' high-content, fluorescence lifetime microscopes.

    PubMed

    Barber, P R; Tullis, I D C; Pierce, G P; Newman, R G; Prentice, J; Rowley, M I; Matthews, D R; Ameer-Beg, S M; Vojnovic, B

    2013-08-01

    We describe a microscopy design methodology and details of microscopes built to this 'open' design approach. These demonstrate the first implementation of time-domain fluorescence microscopy in a flexible automated platform with the ability to ease the transition of this and other advanced microscopy techniques from development to use in routine biology applications. This approach allows easy expansion and modification of the platform capabilities, as it moves away from the use of a commercial, monolithic, microscope body to small, commercial off-the-shelf and custom made modular components. Drawings and diagrams of our microscopes have been made available under an open license for noncommercial use at http://users.ox.ac.uk/~atdgroup. Several automated high-content fluorescence microscope implementations have been constructed with this design framework and optimized for specific applications with multiwell plates and tissue microarrays. In particular, three platforms incorporate time-domain FLIM via time-correlated single photon counting in an automated fashion. We also present data from experiments performed on these platforms highlighting their automated wide-field and laser scanning capabilities designed for high-content microscopy. Devices using these designs also form radiation-beam 'end-stations' at Oxford and Surrey Universities, showing the versatility and extendibility of this approach.

  10. Landward thrusting in accretionary wedges: evidence for seafloor rupture?

    NASA Astrophysics Data System (ADS)

    Cubas, N.; Souloumiac, P.

    2015-12-01

    The 2004 Sumatra and 2011 Japan earthquakes took the community by surprise because they ruptured frontal sections of megathrust thought to slip aseismically. Studying the deformation of accretionary prisms can help in characterizing the specific structures associated to frontal propagation and determining the mechanical properties leading to this behavior. Recent observations suggest a correlation between landward faults and frontal propagation of earthquakes along the Sumatra subduction zone. Large sections of landward thrusts are also observed along Cascadia known to have ruptured in 1700 with a M~9 generating a large tsunami. In this study, we propose to investigate if specific frictional properties could lead to a landward sequence of thrusting with the limit analysis approach. We first show that such sequence requires very low effective friction along the megathrust with a rather high internal effective friction. We also show that landward sequence appears close to the extensional critical limit. We retrieve the megathrust effective friction for three wedges with different sediment incomes. For Cascadia, we find a maximal effective friction of 0.032. For northern and southern Sumatra, we find μ≤0.02 and μ≤ 0.08 respectively. This very low effective friction is probably due to lithostatic pore pressure. This high pore pressure could either be a long-term property or due to dynamic effects such as thermal pressurization. The fact that landward vergence appears far from the compressional critical limit favors a dynamic effect. Indeed, a wedge would move away from this limit if material is added synchronously to the deformation or if it is suddenly submitted to a lower effective friction. In addition, the long-term high pore pressure could be due to a low permeability enhancing thermal pressurization and co-seismic slip along the frontal part of the megathrust.

  11. 28. REPRESENTATIVE CENTER WEDGE. BALANCE WHEELS ON TRACK, WITH RACK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. REPRESENTATIVE CENTER WEDGE. BALANCE WHEELS ON TRACK, WITH RACK TO OUTSIDE, SHOWN TO RIGHT OF THE WEDGE. PHOTO TAKEN AT SOUTH SWING SPAN. - George P. Coleman Memorial Bridge, Spanning York River at U.S. Route 17, Yorktown, York County, VA

  12. Computing pressure distributions in wedges and pinch-outs

    SciTech Connect

    Chih-Cheng Chen; Raghaven, R.

    1995-12-31

    A solution for wedge-type systems in terms of the Laplace transformation is derived. Characteristics of responses are discussed and computational issues are addressed. The algorithm given here is a practical tool for analyzing flows in wedge-type systems and may be incorporated immediately into existing software packages. Existing solutions are a subset of the solution given here.

  13. Magneto-optical and photoemission studies of ultrathin wedges

    SciTech Connect

    Bader, S.D.; Li, Dongqi

    1995-12-01

    Magnetic phase transitions of Fe wedges grown epitaxially on Cu(100) are detected via the surface magneto-optical Kerr effect and used to construct a phase diagram for face centered Fe. Also, the confinement of Cu sp- and d-quantum-well states is studied for Cu/Co(wedge)/Cu(100) utilizing undulator-based photoemission experiments.

  14. 21 CFR 884.5200 - Hemorrhoid prevention pressure wedge.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hemorrhoid prevention pressure wedge. 884.5200... Devices § 884.5200 Hemorrhoid prevention pressure wedge. (a) Identification. A hemorrhoid prevention... hemorrhoids associated with vaginal childbirth. (b) Classification. Class II (special controls). The...

  15. 49 CFR 230.104 - Driving box shoes and wedges.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Driving box shoes and wedges. 230.104 Section 230.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Locomotives and Tenders Running Gear § 230.104 Driving box shoes and wedges. Driving box shoes and...

  16. 49 CFR 230.104 - Driving box shoes and wedges.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Driving box shoes and wedges. 230.104 Section 230.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Locomotives and Tenders Running Gear § 230.104 Driving box shoes and wedges. Driving box shoes and...

  17. 49 CFR 230.104 - Driving box shoes and wedges.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Driving box shoes and wedges. 230.104 Section 230.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Locomotives and Tenders Running Gear § 230.104 Driving box shoes and wedges. Driving box shoes and...

  18. 49 CFR 230.104 - Driving box shoes and wedges.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Driving box shoes and wedges. 230.104 Section 230.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Locomotives and Tenders Running Gear § 230.104 Driving box shoes and wedges. Driving box shoes and...

  19. 49 CFR 230.104 - Driving box shoes and wedges.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Driving box shoes and wedges. 230.104 Section 230.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Locomotives and Tenders Running Gear § 230.104 Driving box shoes and wedges. Driving box shoes and...

  20. Healing period after open high tibial osteotomy and related factors: Can we really say that it is long?

    PubMed

    Yokoyama, Masamichi; Nakamura, Yasuhiro; Onishi, Toru; Hirano, Koji; Doi, Motoyuki

    2016-01-01

    High tibial osteotomy (HTO) is a general procedure for the treatment of degenerative gonarthrosis. In recent years, it has been reported that opening wedge high tibial osteotomy (OWHTO) has become widespread with good results. Despite these facts, HTOs tend to be avoided due to the need for long-term postoperative treatment. To investigate the treatment period for total recovery (healing period) after OWHTO and the factors affecting it. There were 47 cases of medial type degenerative gonarthrosis who underwent OWHTO from 2008 through 2011. The definition of the healing period was based on the time-dependent changes of the Japanese Orthopaedic Association score, focusing especially on pain on walking and pain on ascending/descending stairs. This score was defined as the Ability score. In this study, the healing period ended when the Ability score reached its maximum or when it showed a perfect score. Patients' characteristics were examined to determine their effect on the healing period. The Ability score was 36.7 ± 10.1 (mean ± SD) before surgery and 51.6 ± 5.4 12 months after OWHTO. The healing period was 6.3 ± 3.9 months. Factors correlated with a longer healing period included female sex (correlation coefficient -0.35) and high BMI (correlation coefficient 0.33). Our study suggested that the healing period after OWHTO is approximately 6 months, and patients' BMI and sex appear to be related to this period. This information is expected to be helpful for counseling patients undergoing treatment for gonarthrosis. Level of evidence Therapeutic study, Level IV.

  1. Transmission of a Gaussian beam by a Fizeau interferential wedge.

    PubMed

    Stoykova, Elena

    2005-12-01

    Analysis of transmission of a finite-diameter Gaussian beam by a Fizeau interferential wedge is presented. The fringe calculation is based on angular spectrum expansion of the complex amplitude of the incident wave field. The developed approach is applicable to any beam diameter and wedge thickness at any distance from the wedge and yields as a boundary case the fringes at plane-wave illumination. The spatial region of resonant transmission on the wedge surface is given by the width of the transmitted peak for plane-wave illumination. At higher coating reflectivity, the direction of the transmitted beam is deviated with respect to that of the incident beam. Evaluation of the spectral response based on the spectral width of the transmitted power curve is introduced as more realistic for a correct description of the application of a Fizeau wedge as an interferential selector in laser resonators. PMID:16396037

  2. Effect of friction in wedging of elastic solids

    NASA Technical Reports Server (NTRS)

    Erdogan, F.; Arin, K.

    1976-01-01

    In this paper the contact problem for an elastic wedge of arbitrary angle is considered. It is assumed that the external load is applied to the medium through a rigid wedge and the coefficient of friction between the loading wedge and the elastic solid is constant. The problem is reduced to a singular integral equation of the second kind with the contact pressure as the unknown function. An effective numerical solution of the integral equation is described and the results of three examples are presented. The comparison of these results with those obtained from the frictionless wedge problem indicates that generally friction has the tendency of reducing the peak values of the stress intensity factors calculated at the wedge apex and at the end points of the contact area.

  3. Fabrication of wedged multilayer Laue lenses

    DOE PAGESBeta

    Prasciolu, M.; Leontowich, A. F. G.; Krzywinski, J.; Andrejczuk, A.; Chapman, H. N.; Bajt, S.

    2015-01-01

    We present a new method to fabricate wedged multilayer Laue lenses, in which the angle of diffracting layers smoothly varies in the lens to achieve optimum diffracting efficiency across the entire pupil of the lens. This was achieved by depositing a multilayer onto a flat substrate placed in the penumbra of a straight-edge mask. The distance between the mask and the substrate was calibrated and the multilayer Laue lens was cut in a position where the varying layer thickness and the varying layer tilt simultaneously satisfy the Fresnel zone plate condition and Bragg’s law for all layers in the stack.more » This method can be used to extend the achievable numerical aperture of multilayer Laue lenses to reach considerably smaller focal spot sizes than achievable with lenses composed of parallel layers.« less

  4. Fabrication of wedged multilayer Laue lenses

    SciTech Connect

    Prasciolu, M.; Leontowich, A. F. G.; Krzywinski, J.; Andrejczuk, A.; Chapman, H. N.; Bajt, S.

    2015-01-01

    We present a new method to fabricate wedged multilayer Laue lenses, in which the angle of diffracting layers smoothly varies in the lens to achieve optimum diffracting efficiency across the entire pupil of the lens. This was achieved by depositing a multilayer onto a flat substrate placed in the penumbra of a straight-edge mask. The distance between the mask and the substrate was calibrated and the multilayer Laue lens was cut in a position where the varying layer thickness and the varying layer tilt simultaneously satisfy the Fresnel zone plate condition and Bragg’s law for all layers in the stack. This method can be used to extend the achievable numerical aperture of multilayer Laue lenses to reach considerably smaller focal spot sizes than achievable with lenses composed of parallel layers.

  5. Cesarean section in a wedged head.

    PubMed

    Khosla, A H; Dahiya, K; Sangwan, K

    2003-05-01

    Cesarean section many a times, has to be done late in labour when the head is deeply wedged in the pelvis. The techniques described in standard text books, usually result in extension of the incision either laterally into the broad ligament or vertically upwards into the upper segment or downwards posterior to the bladder from the centre of the incision line. In this study we have reviewed the Patwardhan's technique for the extraction of baby and fetomaternal outcome was compared with cases where this technique was not used. There was no extension of the incision either laterally into broad ligament or upwards or downwards. Haemorrhage due to extension of incision requiring blood transfusion occurred in 24% of patients in group II as compared to nil in group I. PMID:14514249

  6. Configuration and Generation of Substorm Current Wedge

    NASA Astrophysics Data System (ADS)

    Chu, Xiangning

    The substorm current wedge (SCW), a core element of substorm dynamics coupling the magnetotail to the ionosphere, is crucial in understanding substorms. It has been suggested that the field-aligned currents (FACs) in the SCW are caused by either pressure gradients or flow vortices, or both. Our understanding of FAC generations is based predominately on numerical simulations, because it has not been possible to organize spacecraft observations in a coordinate system determined by the SCW. This dissertation develops an empirical inversion model of the current wedge and inverts midlatitude magnetometer data to obtain the parameters of the current wedge for three solar cycles. This database enables statistical data analysis of spacecraft plasma and magnetic field observations relative to the SCW coordinate. In chapter 2, a new midlatitude positive bay (MPB) index is developed and calculated for three solar cycles of data. The MPB index is processed to determine the substorm onset time, which is shown to correspond to the auroral breakup onset with at most 1-2 minutes difference. Substorm occurrence rate is found to depend on solar wind speed while substorm duration is rather constant, suggesting that substorm process has an intrinsic pattern independent of external driving. In chapter 3, an SCW inversion technique is developed to determine the strength and locations of the FACs in an SCW. The inversion parameters for FAC strength and location, and ring current strength are validated by comparison with other measurements. In chapter 4, the connection between earthward flows and auroral poleward expansion is examined using improved mapping, obtained from a newly-developed dynamic magnetospheric model by superimposing a standard magnetospheric field model with substorm current wedge obtained from the inversion technique. It is shown that the ionospheric projection of flows observed at a fixed point in the equatorial plane map to the bright aurora as it expands poleward

  7. Two-dimensional electronic spectroscopy with birefringent wedges

    SciTech Connect

    Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio

    2014-12-15

    We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

  8. Open air demolition of facilities highly contaminated with plutonium

    SciTech Connect

    Lloyd, E.R.; Lackey, M.B.; Stevens, J.M.; Zinsli, L.C.

    2007-07-01

    The demolition of highly contaminated plutonium buildings usually is a long and expensive process that involves decontaminating the building to near free- release standards and then using conventional methods to remove the structure. It doesn't, however, have to be that way. Fluor has torn down buildings highly contaminated with plutonium without excessive decontamination. By removing the select source term and fixing the remaining contamination on the walls, ceilings, floors, and equipment surfaces; open-air demolition is not only feasible, but it can be done cheaper, better (safer), and faster. Open-air demolition techniques were used to demolish two highly contaminated buildings to slab-on-grade. These facilities on the Department of Energy's Hanford Site were located in, or very near, compounds of operating nuclear facilities that housed hundreds of people working on a daily basis. To keep the facilities operating and the personnel safe, the projects had to be creative in demolishing the structures. Several key techniques were used to control contamination and keep it within the confines of the demolition area: spraying fixatives before demolition; applying fixative and misting with a fine spray of water as the buildings were being taken down; and demolishing the buildings in a controlled and methodical manner. In addition, detailed air-dispersion modeling was done to establish necessary building and meteorological conditions and to confirm the adequacy of the proposed methods. Both demolition projects were accomplished without any spread of contamination outside the modest buffer areas established for contamination control. Furthermore, personnel exposure to radiological and physical hazards was significantly reduced by using heavy equipment rather than 'hands on' techniques. (authors)

  9. OPEN AIR DEMOLITION OF FACILITIES HIGHLY CONTAMINATED WITH PLUTONIUM

    SciTech Connect

    LLOYD, E.R.

    2007-05-31

    The demolition of highly contaminated plutonium buildings usually is a long and expensive process that involves decontaminating the building to near free- release standards and then using conventional methods to remove the structure. It doesn't, however, have to be that way. Fluor has torn down buildings highly contaminated with plutonium without excessive decontamination. By removing the select source term and fixing the remaining contamination on the walls, ceilings, floors, and equipment surfaces; open-air demolition is not only feasible, but it can be done cheaper, better (safer), and faster. Open-air demolition techniques were used to demolish two highly contaminated buildings to slab-on-grade. These facilities on the Department of Energy's Hanford Site were located in, or very near, compounds of operating nuclear facilities that housed hundreds of people working on a daily basis. To keep the facilities operating and the personnel safe, the projects had to be creative in demolishing the structures. Several key techniques were used to control contamination and keep it within the confines of the demolition area: spraying fixatives before demolition; applying fixative and misting with a fine spray of water as the buildings were being taken down; and demolishing the buildings in a controlled and methodical manner. In addition, detailed air-dispersion modeling was done to establish necessary building and meteorological conditions and to confirm the adequacy of the proposed methods. Both demolition projects were accomplished without any spread of contamination outside the modest buffer areas established for contamination control. Furthermore, personnel exposure to radiological and physical hazards was significantly reduced by using heavy equipment rather than ''hands on'' techniques.

  10. Productive high-performance software for OpenCL devices

    NASA Astrophysics Data System (ADS)

    Melonakos, John M.; Yalamanchili, Pavan; McClanahan, Chris; Arshad, Umar; Landes, Michael; Jamboti, Shivapriya; Joshi, Abhijit; Mohammed, Shehzan; Spafford, Kyle; Venugopalakrishnan, Vishwanath; Malcolm, James

    2013-05-01

    Over the last three decades, CPUs have continued to produce large performance improvements from one generation to the next. However, CPUs have recently hit a performance wall and need parallel computing to move forward. Parallel computing over the next decade will become increasingly defined by heterogeneous computing, involving the use of accelerators in addition to CPUs to get computational tasks done. In order to use an accelerator, software changes must be made. Regular x86-based compilers cannot compile code to run on accelerators without these needed changes. The amount of software change required varies depending upon the availability of and reliance upon software tools that increase performance and productivity. Writing software that leverages the best parallel computing hardware, adapts well to the rapid pace of hardware updates, and minimizes developer muscle is the industry's goal. OpenCL is the standard around which developers are able to achieve parallel performance. OpenCL itself is too difficult to program to receive general adoptions, but productive high-performing software libraries are becoming increasingly popular and capable in delivering lasting value to user applications.

  11. Non-Coulomb wedges, wrong-way thrusting, and natural hazards in Cascadia

    NASA Astrophysics Data System (ADS)

    Gutscher, Marc-André; Klaeschen, Dirk; Flueh, Ernst; Malavieille, Jacques

    2001-05-01

    Landward vergence in accretionary wedges is an uncommon phenomenon not readily explained by classical Mohr-Coulomb critical wedge theory. Predominantly landward- vergent thrust faults are observed along the Cascadia convergent margin from 45°N to 48°N. We present depth-migrated multichannel seismic images of the internal structure of the accretionary wedge offshore Washington collected during the ORWELL project in 1996. These reveal a high p-wave velocity (≥4 km/s) basal layer that thickens landward and serves as a décollement for a series of overlying landward-vergent thrust faults. Analog modeling using a ductile basal layer consisting of silicone putty produces an array of trenchward-propagating, landward-vergent thrusts and offers a plausible mechanical model for the evolution of these structures. The rheological properties of a basal calcareous mudstone layer offshore Cascadia are discussed in relation to the mechanics of landward vergence and to rapid loading due to the prograding Nitinat and Astoria deep-sea fans. A viscoelastic layer beneath the accretionary wedge is considered to be capable of rupturing during great interplate earthquakes and thus represents an increased risk for both the maximum size of such an event and for the generation of tsunamis.

  12. Analysis and measurement of electromagnetic scattering by pyramidal and wedge absorbers

    NASA Technical Reports Server (NTRS)

    Dewitt, B. T.; Burnside, Walter D.

    1986-01-01

    By modifying the reflection coefficients in the Uniform Geometrical Theory of Diffraction a solution that approximates the scattering from a dielectric wedge is found. This solution agrees closely with the exact solution of Rawlins which is only valid for a few minor cases. This modification is then applied to the corner diffraction coefficient and combined with an equivalent current and geometrical optics solutions to model scattering from pyramid and wedge absorbers. Measured results from 12 inch pyramid absorbers from 2 to 18 GHz are compared to calculations assuming the returns add incoherently and assuming the returns add coherently. The measured results tend to be between the two curves. Measured results from the 8 inch wedge absorber are also compared to calculations with the return being dominated by the wedge diffraction. The procedures for measuring and specifying absorber performance are discussed and calibration equations are derived to calculate a reflection coefficient or a reflectivity using a reference sphere. Shaping changes to the present absorber designs are introduced to improve performance based on both high and low frequency analysis. Some prototypes were built and tested.

  13. Accretion in the wake of terrane collision: The Neogene accretionary wedge off Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Fruehn, J.; Von Huene, R.; Fisher, M.A.

    1999-01-01

    Subduction accretion and repeated terrane collision shaped the Alaskan convergent margin. The Yakutat Terrane is currently colliding with the continental margin below the central Gulf of Alaska. During the Neogene the terrane's western part was subducted after which a sediment wedge accreted along the northeast Aleutian Trench. This wedge incorporates sediment eroded from the continental margin and marine sediments carried into the subduction zone on the Pacific plate. Prestack depth migration was performed on six seismic reflection lines to resolve the structure within this accretionary wedge and its backstop. The lateral extent of the structures is constrained by high-resolution swath bathymetry and seismic lines collected along strike. Accretionary structure consists of variably sized thrust slices that were deformed against a backstop during frontal accretion and underplating. Toward the northeast the lower slope steepens, the wedge narrows, and the accreted volume decreases notwith-standing a doubling of sediments thickness in the trench. In the northeasternmost transect, near the area where the terrane's trailing edge subducts, no frontal accretion is observed and the slope is eroded. The structures imaged along the seismic lines discussed here most likely result from progressive evolution from erosion to accretion, as the trailing edge of the Yakutat Terrane is subducting.

  14. Geodetic observations of megathrust earthquakes and backarc wedge deformation across the central Andes

    NASA Astrophysics Data System (ADS)

    Weiss, J. R.; Brooks, B. A.; Foster, J. H.; Bevis, M. G.; Echalar, A.; Caccamise, D.; Heck, J. M.

    2014-12-01

    High-precision Global Positioning System (GPS) data offer an opportunity to investigate active orogenic wedges yet surface velocity fields are available for only a few examples worldwide. More observations are needed to link deformation processes across multiple timescales and to better understand strain accumulation and release in active wedge settings. Here we present a new GPS velocity field for the central Andes and the backarc orogenic wedge comprising the southern Subandes of Bolivia (SSA), a region previously thought to be mostly isolated from the plate boundary earthquake cycle. The time span of our observations (2000 to mid-2014) includes two megathrust earthquakes along the Chile trench that affected the SSA. The 2007 Mw 7.7 Tocopilla, Chile earthquake resulted in a regional postseismic decrease in the eastward component of horizontal surface velocities. Preliminary analysis of the deformation field from the April 01 2014 Mw 8.2 Pisagua, Chile earthquake also indicates a postseismic signal extending into the SSA. We create an interseismic velocity field for the SSA by correcting campaign GPS site velocities for the seasonal cycles estimated from continuous GPS site time series. We remove the effects of both megathrust events by estimating coseismic steps and fitting linear and logarithmic functions to the postseismic GPS site motions. The velocity estimates at most locations increase after correcting for the transients. This finding suggests that forces leading to shortening and earthquakes in the backarc wedge are not as temporally consistent as previously considered.

  15. The acoustical structure of highly porous open-cell foams

    NASA Technical Reports Server (NTRS)

    Lambert, R. F.

    1982-01-01

    This work concerns both the theoretical prediction and measurement of structural parameters in open-cell highly porous polyurethane foams. Of particular interest are the dynamic flow resistance, thermal time constant, and mass structure factor and their dependence on frequency and geometry of the cellular structure. The predictions of cell size parameters, static flow resistance, and heat transfer as accounted for by a Nusselt number are compared with measurement. Since the static flow resistance and inverse thermal time constant are interrelated via the 'mean' pore size parameter of Biot, only two independent measurements such as volume porosity and mean filament diameter are required to make the predictions for a given fluid condition. The agreements between this theory and nonacoustical experiments are excellent.

  16. The Cimmerian accretionary wedge of Anarak, Central Iran

    NASA Astrophysics Data System (ADS)

    Zanchi, Andrea; Malaspina, Nadia; Zanchetta, Stefano; Berra, Fabrizio; Benciolini, Luca; Bergomi, Maria; Cavallo, Alessandro; Javadi, Hamid Reza; Kouhpeyma, Meyssam

    2015-04-01

    The occurrence in Iran of several ophiolite belts dating between Late Palaeozoic to Triassic poses several questions on the possible existence of various sutures marking the closure of the Palaeotethys ocean between Eurasia and this Gondwana-derived microplate. In this scenario, the Anarak region in Central Iran still represents a conundrum. Contrasting geochronological, paleontological, paleomagnetic data and reported field evidence suggest different origins for the Anarak Metamorphic Complex (AMC). The AMC is either interpreted, as: (1) relict of an accretionary wedge developed at the Eurasia margin during the Palaeotethys subduction as part of the Cimmerian suture zone of NE Iran, displaced to Central Iran by a large counter-clockwise rotation of the central Iranian blocks; (2) autochthonous unit forming a secondary branch of the main suture zone. Our structural, petrographic and geochemical data indicate that the AMC consists of several metamorphic units also including dismembered "ophiolites" which display different tectono-metamorphic evolutions. Three main ductile deformational events can be distinguished in the AMC. The Morghab and Chah Gorbeh complexes preserve a different M1 metamorphism, characterized by blueschist relics in the S1 foliation of the former unit, and greenschist assemblages in the latter. They share a subsequent similar D2 deformational and M2 metamorphic history, showing a prograde metamorphism with syn- to post-deformation growth of blueschist facies mineral assemblages on pre-existing greenschist facies associations. High pressure, low temperature (HP/LT) metamorphism responsible for the growth of sodic amphibole has been recognized also within marble lenses at the contact between the Chah Gorbeh Complex and serpentinites. Evidence of HP/LT metamorphism also occurs in glaucophane-bearing meta-pillow lavas and serpentinites, which contain antigorite and form most of the "ophiolites" within the AMC. Structural relationships show that the

  17. A high power microwave triggered RF opening switch.

    PubMed

    Beeson, S; Dickens, J; Neuber, A

    2015-03-01

    A 4-port S-band waveguide structure was designed and fabricated such that a signal of any amplitude (less than 1 MW) can be switched from a normally closed state, <0.5 dB insertion loss (IL), to an open state >30 dB IL by initiating plasma in a gas cell situated at the junction of this waveguide and one propagating a megawatt level magnetron pulse. The 90/10 switching time is as low as 20 ns with a delay of ∼30 ns between the onset of the high power microwave pulse and the initial drop of the signal. Two ports of this device are for the high power triggering pulse while the other two ports are for the triggered signal in a Moreno-like coupler configuration. In order to maintain high isolation, these two sets of waveguides are rotated 90° from each other with a TE111 resonator/plasma cell located at the intersection. This manuscript describes the design and optimization of this structure using COMSOL 4.4 at the design frequency of 2.85 GHz, comparison of simulated scattering parameters with measured "cold tests" (testing without plasma), and finally the temporal waveforms of this device being used to successfully switch a low power CW signal from 2 W to <5 mW on a sub-microsecond timescale. PMID:25832255

  18. A high power microwave triggered RF opening switch.

    PubMed

    Beeson, S; Dickens, J; Neuber, A

    2015-03-01

    A 4-port S-band waveguide structure was designed and fabricated such that a signal of any amplitude (less than 1 MW) can be switched from a normally closed state, <0.5 dB insertion loss (IL), to an open state >30 dB IL by initiating plasma in a gas cell situated at the junction of this waveguide and one propagating a megawatt level magnetron pulse. The 90/10 switching time is as low as 20 ns with a delay of ∼30 ns between the onset of the high power microwave pulse and the initial drop of the signal. Two ports of this device are for the high power triggering pulse while the other two ports are for the triggered signal in a Moreno-like coupler configuration. In order to maintain high isolation, these two sets of waveguides are rotated 90° from each other with a TE111 resonator/plasma cell located at the intersection. This manuscript describes the design and optimization of this structure using COMSOL 4.4 at the design frequency of 2.85 GHz, comparison of simulated scattering parameters with measured "cold tests" (testing without plasma), and finally the temporal waveforms of this device being used to successfully switch a low power CW signal from 2 W to <5 mW on a sub-microsecond timescale.

  19. Analysis of Oblique Wedges Using Analog and Numerical Models

    NASA Astrophysics Data System (ADS)

    Haq, S. S.; Koster, K.; Martin, R. S.; Flesch, L. M.

    2010-12-01

    Oblique plate motion is understood to be a primary factor in determining the style and location of deformation at many convergent margins. These margins are frequently characterized by a dominant strike-slip fault parallel to the margin, which accommodates margin-parallel motion and shear and is adjacent to partitioned and near margin-normal thrusting. We have performed a series of analog experiment in which we have simulated oblique wedges with frictional and layered, friction over viscous, rheologies. Using the detailed analysis of topography and strain from these analog models we have compared them to geometrically similar 2D and 3D numerical models. While our pure frictional analog wedges are characterized by numerous discrete thrust faults in the pro-wedge and a zone of shear between the pro-wedge and the retro-wedges, our layered wedges have a dominate shear zone that is long-lived. In all models the highest rate of contractional deformation is at the thrust front, while the highest rate of shear is isolated in a relatively narrow zone at the back of the pro-wedge. Because the layered analog wedge is better able isolate shear behind the pro-wedge it can better partition strain into dip-slip thrusting normal to the margin. Our numerical simulations support the assertion that a relatively small amount of extensional stress is needed to play a significant role in the structural evolution of convergent systems. However, the manner in which this stress is localized on discrete structures, and in particular, how the style of strain (extension or contraction) will evolve, is a strong function of rheology and its strength at depth for a given initial geometry.

  20. Recirculating wedges for metal-vapor plasma tubes

    DOEpatents

    Hall, J.P.; Sawvel, R.M.; Draggoo, V.G.

    1994-06-28

    A metal vapor laser is disclosed that recycles condensed metal located at the terminal ends of a plasma tube back toward the center of the tube. A pair of arcuate wedges are incorporated on the bottom of the plasma tube near the terminal ends. The wedges slope downward toward the center so that condensed metal may be transported under the force of gravity away from the terminal ends. The wedges are curved to fit the plasma tube to thereby avoid forming any gaps within the tube interior. 8 figures.

  1. Recirculating wedges for metal-vapor plasma tubes

    DOEpatents

    Hall, Jerome P.; Sawvel, Robert M.; Draggoo, Vaughn G.

    1994-01-01

    A metal vapor laser is disclosed that recycles condensed metal located at the terminal ends of a plasma tube back toward the center of the tube. A pair of arcuate wedges are incorporated on the bottom of the plasma tube near the terminal ends. The wedges slope downward toward the center so that condensed metal may be transported under the force of gravity away from the terminal ends. The wedges are curved to fit the plasma tube to thereby avoid forming any gaps within the tube interior.

  2. Octave spanning wedge dispersive mirrors with low dispersion oscillations.

    PubMed

    Habel, Florian; Shirvanyan, Vage; Trubetskov, Michael; Burger, Christian; Sommer, Annkatrin; Kling, Matthias F; Schultze, Martin; Pervak, Vladimir

    2016-05-01

    A novel concept for octave spanning dispersive mirrors with low spectral dispersion oscillations is presented. The key element of the so-called wedge dispersive mirror is a slightly wedged layer which is coated on a specially optimized dispersive multilayer stack by a common sputter coating process. The group delay dispersion (GDD) of a pulse reflected on a wedge dispersive mirror is nearly free of oscillations. Fabricated mirrors with negative GDD demonstrate the compression of a pulse down to 3.8 fs as good as double angled mirrors optimized for the same bandwidth.

  3. High Tibial Osteotomy

    PubMed Central

    Byun, Seong Joon

    2012-01-01

    High tibial osteotomy (HTO) is a widely performed procedure to treat medial knee arthrosis. In general, published studies on HTO report good long-term results with a correct patient selection and a precise surgical technique. The ideal candidate for an HTO is a middle aged patient (60 to 65 years of age), with isolated medial osteoarthritis, with good range of motion and without ligamentous instability. Some issues that need resolution remain; these include the choice between opening and closing wedge tibial osteotomy, the graft selection in opening wedge osteotomies, the type of fixation, the comparison with unicompartmental knee arthroplasty and whether HTO significantly affects a subsequent total joint replacement. Precise indication, preoperative planning, and operative technique selection are essential to achieve good results. PMID:22708105

  4. Complex interactions between diapirs and 4-D subduction driven mantle wedge circulation.

    NASA Astrophysics Data System (ADS)

    Sylvia, R. T.; Kincaid, C. R.

    2015-12-01

    Analogue laboratory experiments generate 4-D flow of mantle wedge fluid and capture the evolution of buoyant mesoscale diapirs. The mantle is modeled with viscous glucose syrup with an Arrhenius type temperature dependent viscosity. To characterize diapir evolution we experiment with a variety of fluids injected from multiple point sources. Diapirs interact with kinematically induced flow fields forced by subducting plate motions replicating a range of styles observed in dynamic subduction models (e.g., rollback, steepening, gaps). Data is collected using high definition timelapse photography and quantified using image velocimetry techniques. While many studies assume direct vertical connections between the volcanic arc and the deeper mantle source region, our experiments demonstrate the difficulty of creating near vertical conduits. Results highlight extreme curvature of diapir rise paths. Trench-normal deflection occurs as diapirs are advected downward away from the trench before ascending into wedge apex directed return flow. Trench parallel deflections up to 75% of trench length are seen in all cases, exacerbated by complex geometry and rollback motion. Interdiapir interaction is also important; upwellings with similar trajectory coalesce and rapidly accelerate. Moreover, we observe a new mode of interaction whereby recycled diapir material is drawn down along the slab surface and then initiates rapid fluid migration updip along the slab-wedge interface. Variability in trajectory and residence time leads to complex petrologic inferences. Material from disparate source regions can surface at the same location, mix in the wedge, or become fully entrained in creeping flow adding heterogeneity to the mantle. Active diapirism or any other vertical fluid flux mechanism employing rheological weakening lowers viscosity in the recycling mantle wedge affecting both solid and fluid flow characteristics. Many interesting and insightful results have been presented based

  5. The OpenCourseWare Model: High-Impact Open Educational Content

    ERIC Educational Resources Information Center

    Carson, Stephen

    2007-01-01

    OpenCourseWare (OCW) is one among several models for offering open educational resources (OER). This article explains the OCW model and its position within the broader OER context. OCW primarily represents publication of existing course materials already in use for teaching purposes. OCW projects are most often institutional, carrying the…

  6. Effective Thermal Conductivity of High Porosity Open Cell Nickel Foam

    NASA Technical Reports Server (NTRS)

    Sullins, Alan D.; Daryabeigi, Kamran

    2001-01-01

    The effective thermal conductivity of high-porosity open cell nickel foam samples was measured over a wide range of temperatures and pressures using a standard steady-state technique. The samples, measuring 23.8 mm, 18.7 mm, and 13.6 mm in thickness, were constructed with layers of 1.7 mm thick foam with a porosity of 0.968. Tests were conducted with the specimens subjected to temperature differences of 100 to 1000 K across the thickness and at environmental pressures of 10(exp -4) to 750 mm Hg. All test were conducted in a gaseous nitrogen environment. A one-dimensional finite volume numerical model was developed to model combined radiation/conduction heat transfer in the foam. The radiation heat transfer was modeled using the two-flux approximation. Solid and gas conduction were modeled using standard techniques for high porosity media. A parameter estimation technique was used in conjunction with the measured and predicted thermal conductivities at pressures of 10(exp -4) and 750 mm Hg to determine the extinction coefficient, albedo of scattering, and weighting factors for modeling the conduction thermal conductivity. The measured and predicted conductivities over the intermediate pressure values differed by 13%.

  7. Serpentinisation of the Mantle Wedge Controls the Chemistry of Arc Magmas

    NASA Astrophysics Data System (ADS)

    Yardley, B. W.

    2008-12-01

    Arc magmas are derived from mantle wedge source regions that are more highly oxidised than other parts of the mantle but the cause of the oxidation is not well understood. Conventionally it has been attributed to influx of water derived from dehydration of the underlying slab, but this possibility has been comprehensively debunked by Frost et al. (1998). A direct link to the introduction of the fluids that flux melting fails to explain the ubiquitous high oxygen fugacity of xenoliths from this region, which point to extensive oxidation of the wedge. If it is not possible to introduce excess oxygen to the mantle wedge, it is likely that the oxidation arises from residual enrichment in oxygen due to dissociation of water and subsequent loss of hydrogen. Serpentinisation is the only geological process that generates sufficiently reducing conditions for water to dissociate, and it allows hydrogen fugacities to rise to sufficiently high levels for hydrogen to be lost as a migrating vapour phase. Because it creates magnetite, serpentinisation results in an increase in the Fe3+ content of the serpentinised rocks, which means that if subsequent heating regenerates less hydrous peridotite assemblages, the magnetite content of their spinel phase will be higher than in the precursor peridotite. For these regenerated peridotites, the greater magnetite content results in a higher oxygen fugacity than for the precursor peridotite. Hence the high Fe3+ signature generated during serpentine growth is carried down by flow in the wedge beyond the temperatures of serpentine breakdown and results in generation of high Fe3+:Fe2+ magmas. The main introduction of slab volatiles to the mantle wedge takes place at low temperatures, probably above 50km depth, where fluids are more abundant than at greater depths. This interpretation is consistent with geological and geophysical evidence for the existence of a serpentine body immediately above the slab in both ancient and modern subduction

  8. Laparoscopic wedge resection and partial nephrectomy--the Washington University experience and review of the literature.

    PubMed

    McDougall, E M; Elbahnasy, A M; Clayman, R V

    1998-01-01

    Open partial nephrectomy is an accepted form of treatment for a variety of benign conditions and for localized renal cell carcinoma. To date, there is limited experience with the clinical application of laparoscopic partial nephrectomy and wedge resection for benign and malignant disease of the kidney. Herein, we report our clinical experience with laparoscopic partial nephrectomy and a review of the current literature. Twelve patients (27-81 years) have undergone laparoscopic wedge resection (3) or attempted polar partial nephrectomy (9) since 1993. In the group of 12 patients, 5 had a mass suspicious for a malignancy, 4 patients had symptomatic polar calyceal dilation with or without stone disease, and 3 patients had an atrophic or hydronephrotic upper pole moiety. Among the patients in the polar nephrectomy group, a third were converted to an open procedure. The remaining 6 patients had a mean operative time of 6.5 hours (5.7-8.3 hours). These patients resumed their oral intake on average 0.8 days postoperatively. In the 2 patients with a mass, the final pathology was oncocytoma (1), and xanthogranulomatous reaction in a renal cyst (1). Postoperative complications included a nephrocutaneous fistula which was endoscopically fulgurated, a retroperitoneal urinoma which was percutaneously drained, and a two-day bout of ileus. The mean hospital stay was 5.3 days (2-9). Their full convalescence was completed in a mean of 4.2 weeks (2-8). Three patients underwent a wedge resection for a superficial < 2 cm mass. The average operative time in this group was 3.5 hours (2-5.4). The mean time to resuming oral intake was 0.7 days (0.3-0.7). The final pathology was oncocytoma (1), oncocytic renal cell cancer (1), and old infarction (1); none of the patients had any complications. The mean hospital stay was 2.7 days (2-4). Convalescence was completed in 4 weeks (range 1-8). Laparoscopic wedge resection and polar partial nephrectomy are feasible, albeit currently tedious

  9. HOS-ocean: Open-source solver for nonlinear waves in open ocean based on High-Order Spectral method

    NASA Astrophysics Data System (ADS)

    Ducrozet, Guillaume; Bonnefoy, Félicien; Le Touzé, David; Ferrant, Pierre

    2016-06-01

    HOS-ocean is an efficient High-Order Spectral code developed to solve the deterministic propagation of nonlinear wavefields in open ocean. HOS-ocean is released as open-source, developed and distributed under the terms of GNU General Public License (GPLv3). Along with the source code, a documentation under wiki format is available which makes easy the compilation and execution of the source files. The code has been shown to be accurate and efficient.

  10. VIEW OF LINE OF DRILL HOLES WITH METAL WEDGES, IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF LINE OF DRILL HOLES WITH METAL WEDGES, IN NORTHERN QUARRY AREA, FACING NORTH - Granite Hill Plantation, Quarry No. 2, South side of State Route 16, 1.3 miles northeast east of Sparta, Sparta, Hancock County, GA

  11. VIEW OF LINE OF DRILL HOLES WITH METAL WEDGES, IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF LINE OF DRILL HOLES WITH METAL WEDGES, IN NORTHERN QUARRY AREA, FACING SOUTHEAST - Granite Hill Plantation, Quarry No. 2, South side of State Route 16, 1.3 miles northeast east of Sparta, Sparta, Hancock County, GA

  12. DETAIL VIEW OF THREEPART METAL WEDGE EMBEDDED IN EDGE OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF THREE-PART METAL WEDGE EMBEDDED IN EDGE OF QUARRY WALL, FACING NORTHWEST - Granite Hill Plantation, Quarry No. 3, South side of State Route 16, 1.3 miles northeast east of Sparta, Sparta, Hancock County, GA

  13. DETAIL VIEW OF THREEPART METAL WEDGE EMBEDDED IN EDGE OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF THREE-PART METAL WEDGE EMBEDDED IN EDGE OF QUARRY WALL, FACING EAST - Granite Hill Plantation, Quarry No. 3, South side of State Route 16, 1.3 miles northeast east of Sparta, Sparta, Hancock County, GA

  14. High School Open On-Line Courses (HOOC): A Case Study from Italy

    ERIC Educational Resources Information Center

    Canessa, Enrique; Pisani, Armando

    2013-01-01

    The first implementation of complete high school, open on-line courses (HOOC) aiming to support the training and basic scientific knowledge of young students from the Liceo Ginnasio Dante Alighieri in Gorizia, Italy, is discussed. Using the open source and automated recording system openEyA, HOOC give a student the opportunity to watch on-line, at…

  15. OpenACC to FPGA: A Framework for Directive-based High-Performance Reconfigurable Computing

    SciTech Connect

    Lee, Seyong; Vetter, Jeffrey S

    2016-01-01

    This paper presents a directive-based, high-level programming framework for high-performance reconfigurable computing. It takes a standard, portable OpenACC C program as input and generates a hardware configuration file for execution on FPGAs. We implemented this prototype system using our open-source OpenARC compiler; it performs source-to-source translation and optimization of the input OpenACC program into an OpenCL code, which is further compiled into a FPGA program by the backend Altera Offline OpenCL compiler. Internally, the design of OpenARC uses a high- level intermediate representation that separates concerns of program representation from underlying architectures, which facilitates portability of OpenARC. In fact, this design allowed us to create the OpenACC-to-FPGA translation framework with minimal extensions to our existing system. In addition, we show that our proposed FPGA-specific compiler optimizations and novel OpenACC pragma extensions assist the compiler in generating more efficient FPGA hardware configuration files. Our empirical evaluation on an Altera Stratix V FPGA with eight OpenACC benchmarks demonstrate the benefits of our strategy. To demonstrate the portability of OpenARC, we show results for the same benchmarks executing on other heterogeneous platforms, including NVIDIA GPUs, AMD GPUs, and Intel Xeon Phis. This initial evidence helps support the goal of using a directive-based, high-level programming strategy for performance portability across heterogeneous HPC architectures.

  16. Modeling Structural and Mechanical Responses to Localized Erosional Processes on a Bivergent Orogenic Wedge

    NASA Astrophysics Data System (ADS)

    Marzen, R.; Morgan, J. K.

    2014-12-01

    Critical Coulomb wedge theory established that orogenic and accretionary wedges should develop self-similarly and maintain a critical taper that reflects the balance of strength of the wedge material and a basal décollement. However, a variety of geological processes can perturb that balance, forcing readjustment of the wedge. For example, glacial erosion and landsliding can concentrate erosion on a localized portion of the wedge slope, leaving that portion of the wedge with an out-of-equilibrium slope that would need to re-develop for the wedge to resume self-similar growth. We use the discrete element method to analyze how growing bivergent wedges with different cohesive strengths respond structurally and mechanically to erosional events localized along upper, middle, and lower segments of the pro-wedge. Mechanically, pro-wedge erosion results in a sudden decrease followed by a quick recovery of the mean stress and maximum shear stress throughout the pro-wedge. However, when erosion is localized in the mid- to lower portions of the pro-wedge, a zone of increased mean stress develops where the wedge is concentrating deformation to recover its taper. In contrast, when erosion is localized in the upper axial zone, there is almost no recovery of the wedge taper, reflecting the fact that the material at the top of the wedge is being carried passively in a transition zone between the pro-wedge and retro-wedge. Structurally, wedges composed of lower cohesion material recover their critical taper almost immediately through distributed deformation, while wedges of higher-cohesion material recover more slowly, and incompletely, by concentrating deformation along existing fault surfaces. As a result, localized erosional episodes can have a lasting effect on the wedge morphology when the wedge is composed of higher cohesion material.

  17. Laparoscopic partial nephrectomy and wedge resection.

    PubMed

    Kozlowski, P M; Winfield, H N

    2000-12-01

    Partial nephrectomy is a more challenging operation than radical or simple nephrectomy, primarily because of the risk of complications such as bleeding. This problem is even more troublesome with minimally invasive approaches because of the dearth of effective hemostatic instruments and supplies. The location of the lesion determines whether a transperitoneal or a retroperitoneal route will be employed. Centrally located or anterior renal lesions generally are approached transperitoneally whereas peripheral lateral or posterior lesions are accessed by retroperitoneoscopy. The Harmonic Scalpel with slow cutting and high coagulation settings is useful for incising the renal capsule and parenchyma. The argon beam coagulator is helpful to stop any persistent bleeding. The few reported series of laparoscopic partial nephrectomy indicate considerably longer operative times than are needed for open surgery and hospitalization of upwards of 5 days, largely to monitor drainage and urine leakage. It is hoped that this advanced laparoscopic technique will become more user friendly with further developments in techniques and instrumentation to provide patients with the expected benefits of minimally invasive surgery.

  18. Stem thrust prediction model for W-K-M double wedge parallel expanding gate valves

    SciTech Connect

    Eldiwany, B.; Alvarez, P.D.; Wolfe, K.

    1996-12-01

    An analytical model for determining the required valve stem thrust during opening and closing strokes of W-K-M parallel expanding gate valves was developed as part of the EPRI Motor-Operated Valve Performance Prediction Methodology (EPRI MOV PPM) Program. The model was validated against measured stem thrust data obtained from in-situ testing of three W-K-M valves. Model predictions show favorable, bounding agreement with the measured data for valves with Stellite 6 hardfacing on the disks and seat rings for water flow in the preferred flow direction (gate downstream). The maximum required thrust to open and to close the valve (excluding wedging and unwedging forces) occurs at a slightly open position and not at the fully closed position. In the nonpreferred flow direction, the model shows that premature wedging can occur during {Delta}P closure strokes even when the coefficients of friction at different sliding surfaces are within the typical range. This paper summarizes the model description and comparison against test data.

  19. CHIRP seismic reflection study of falling-stage (forced regressive) sediment wedges on the New Jersey outer continental shelf

    NASA Astrophysics Data System (ADS)

    Santra, M.; Goff, J.; Ron, S.; Austin, J.

    2007-12-01

    High-resolution (1-12 kHz), deep-towed and hull-mounted CHIRP seismic data were collected on the New Jersey outer shelf in 2001, 2002 and 2006 as part of Office of Naval Research-funded projects. These data have imaged two well-developed, offlapping sedimentary wedges (named outer-shelf wedge and deep-shelf wedge) that are now postulated to have developed on the falling-stage limb of the last glacial cycle, during some time prior to the Last Glacial Maximum (20-22 kyrs BP). These wedges formed atop the high-amplitude, regional R horizon, a complex erosional unconformity that formed about 40,000 years ago. The outer shelf wedge is also characterized in part by an enigmatic, erose boundary separating layered horizons below from a mostly transparent section above. New Jersey shelf wedges appear analogous to forced-regressive units imaged on the Rhone shelf edge, as well as Eocene sections documented from seismic-scale outcrops on Spitsbergen Island. These examples can reach thicknesses up to 100 m on the shelf edge and uppermost slope, but usually thin rapidly downslope. Such wedges represent one of two documented mechanisms involving sand transport across a shelf margin into deeper water settings, the other being a canyonized shelf-edge. Our study will includes analysis of the CHIRP data and, if available, additional ground truth provided by short cores collected in summer 2007 at numerous intra-wedge stratigraphic horizons. Our goals are to understand the external and internal geometry of the wedges and sediment pathways across the paleo-shelf. These data should allow us to characterize margin segments that build during sea-level fall by slope-apron accretion rather than by the formation of channel-levee complexes. The literature is heavily weighted by the latter and their associated canyon systems, but information on shelf-edge attached slope aprons and how they contribute to deep-water sedimentation, and in particular the delivery of clean sands to slope settings

  20. Role of Hydrogen in stagnant slabs and big mantle wedge

    NASA Astrophysics Data System (ADS)

    Ohtani, E.; Zhao, D.

    2008-12-01

    Eastern China, Europe, and United State (e.g., [7]). According to the BMW model by Zhao [2], the intra-plate volcanisms in Northeast China including Mt. Changbai are different from the hot plumes and they might be generated due to some processes related to the deep-seated dehydration from the stagnant slab. Recent geochemical studies on volcanic rocks and associated mantle xenoliths in Northeast China (e.g., [8]) indicated that there is no geochemical evidence for involvement of subducting slab in most basalts, i.e., no depletion of high field strength elements and no enrichment of large ion lithophile elements. There is no clear evidence for a high-3He/4He mantle plume component in these rocks, i.e., 3He/4He ratios are significantly below the high 3He/4He ratios of mantle plumes such as those beneath Hawaii and Iceland. The geochemical signatures of the deep dehydration should be different from those in the conventional mantle wedge, since the fluids generated at such depths are completely different from those at the shallow depths. Further studies including the element partitioning between fluids and mantle under the deep upper mantle and the transition zone conditions are necessary to clarify the possible role of the Big Mantle Wedge on the intra-plate volcanism. [1] Fukao, et al., J. G. R. 108, doi:10.1029/2001JB000989, 2003. [2] Zhao et al., Chin. Sci. Bulletin 49, 1401, 2004, [3] Ohtani, Elements, 1, 25, 2005. [4] Richard et al., EPSL, 251, 156, 2006. [5] Hae et al., EPSL, 243, 141, 2006. [6] Litasov and Ohtani, PEPI, 134, 105, 2002. [7] Song et al., Nature, 427, 530, 2004. [8] Chen et al., Lithos, 96, 108, 2007

  1. Hydrodynamic controls on oxygen dynamics in a riverine salt wedge estuary, the Yarra River estuary, Australia

    NASA Astrophysics Data System (ADS)

    Bruce, L. C.; Cook, P. L. M.; Teakle, I.; Hipsey, M. R.

    2014-04-01

    Oxygen depletion in coastal and estuarine waters has been increasing rapidly around the globe over the past several decades, leading to decline in water quality and ecological health. In this study we apply a numerical model to understand how salt wedge dynamics, changes in river flow and temperature together control oxygen depletion in a micro-tidal riverine estuary, the Yarra River estuary, Australia. Coupled physical-biogeochemical models have been previously applied to study how hydrodynamics impact upon seasonal hypoxia; however, their application to relatively shallow, narrow riverine estuaries with highly transient patterns of river inputs and sporadic periods of oxygen depletion has remained challenging, largely due to difficulty in accurately simulating salt wedge dynamics in morphologically complex areas. In this study we overcome this issue through application of a flexible mesh 3-D hydrodynamic-biogeochemical model in order to predict the extent of salt wedge intrusion and consequent patterns of oxygen depletion. The extent of the salt wedge responded quickly to the sporadic riverine flows, with the strength of stratification and vertical density gradients heavily influenced by morphological features corresponding to shallow points in regions of tight curvature ("horseshoe" bends). The spatiotemporal patterns of stratification led to the emergence of two "hot spots" of anoxia, the first downstream of a shallow region of tight curvature and the second downstream of a sill. Whilst these areas corresponded to regions of intense stratification, it was found that antecedent conditions related to the placement of the salt wedge played a major role in the recovery of anoxic regions following episodic high flow events. Furthermore, whilst a threshold salt wedge intrusion was a requirement for oxygen depletion, analysis of the results allowed us to quantify the effect of temperature in determining the overall severity and extent of hypoxia and anoxia. Climate

  2. Growth and characterization of epitaxial fcc Fe wedges on diamond (100).

    SciTech Connect

    Bader, S. D.; Keavneu, D. J.; Keune, W.; Li, D.; Pearson, J.

    1997-12-05

    Epitaxial Fe wedges with a thickness gradation from 0--20 {angstrom} were grown on diamond(100) at room temperature, subsequently annealed, and investigated with reflection high-energy electron diffraction and the surface magneto-optical Kerr effect. The results indicate that for <5 monolayer thicknesses the Fe grows on C(100) as smooth, epitaxial fcc films, which are not ferromagnetic, but that thicker films undergo a transition to become rough and the ordinary bcc ferromagnetic phase.

  3. Effects of slot closure by soft magnetic powder wedge material in axial-field permanent magnet brushless machines

    NASA Astrophysics Data System (ADS)

    Gair, S.; Eastham, J. F.; Canova, A.

    1996-04-01

    The article reports on a study of the effects of slot closure in axial-field permanent magnet brushless machines by a two-dimensional finite element method (2D FEM) of analysis. The closure of the slots is made by using soft magnetic powder wedge material. Parameter values and machine performance for the open and closed slot configuration are computed. In order to test the 2D FEM model, calculated results are compared with measurements and favorable agreement is shown.

  4. Seismological evidence for a sub-volcanic arc mantle wedge beneath the Denali volcanic gap, Alaska

    USGS Publications Warehouse

    McNamara, D.E.; Pasyanos, M.E.

    2002-01-01

    Arc volcanism in Alaska is strongly correlated with the 100 km depth contour of the western Aluetian Wadati-Benioff zone. Above the eastern portion of the Wadati-Benioff zone however, there is a distinct lack of volcanism (the Denali volcanic gap). We observe high Poisson's ratio values (0.29-0.33) over the entire length of the Alaskan subduction zone mantle wedge based on regional variations of Pn and Sn velocities. High Poisson's ratios at this depth (40-70 km), adjacent to the subducting slab, are attributed to melting of mantle-wedge peridotites, caused by fluids liberated from the subducting oceanic crust and sediments. Observations of high values of Poisson's ratio, beneath the Denali volcanic gap suggest that the mantle wedge contains melted material that is unable to reach the surface. We suggest that its inability to migrate through the overlying crust is due to increased compression in the crust at the northern apex of the curved Denali fault.

  5. Aligning Optical Fibers by Means of Actuated MEMS Wedges

    NASA Technical Reports Server (NTRS)

    Morgan, Brian; Ghodssi, Reza

    2007-01-01

    Microelectromechanical systems (MEMS) of a proposed type would be designed and fabricated to effect lateral and vertical alignment of optical fibers with respect to optical, electro-optical, optoelectronic, and/or photonic devices on integrated circuit chips and similar monolithic device structures. A MEMS device of this type would consist of a pair of oppositely sloped alignment wedges attached to linear actuators that would translate the wedges in the plane of a substrate, causing an optical fiber in contact with the sloping wedge surfaces to undergo various displacements parallel and perpendicular to the plane. In making it possible to accurately align optical fibers individually during the packaging stages of fabrication of the affected devices, this MEMS device would also make it possible to relax tolerances in other stages of fabrication, thereby potentially reducing costs and increasing yields. In a typical system according to the proposal (see Figure 1), one or more pair(s) of alignment wedges would be positioned to create a V groove in which an optical fiber would rest. The fiber would be clamped at a suitable distance from the wedges to create a cantilever with a slight bend to push the free end of the fiber gently to the bottom of the V groove. The wedges would be translated in the substrate plane by amounts Dx1 and Dx2, respectively, which would be chosen to move the fiber parallel to the plane by a desired amount Dx and perpendicular to the plane by a desired amount Dy. The actuators used to translate the wedges could be variants of electrostatic or thermal actuators that are common in MEMS.

  6. The effect of foot orthoses and in-shoe wedges during cycling: a systematic review

    PubMed Central

    2014-01-01

    Background The use of foot orthoses and in-shoe wedges in cycling are largely based on theoretical benefits and anecdotal evidence. This review aimed to systematically collect all published research on this topic, critically evaluate the methods and summarise the findings. Methods Study inclusion criteria were: all empirical studies that evaluated the effects of foot orthoses or in-shoe wedges on cycling; outcome measures that investigated physiological parameters, kinematics and kinetics of the lower limb, and power; and, published in English. Studies were located by data-base searching (Medline, CINAHL, Embase and SPORTDiscus) and hand-searching in February 2014. Selected studies were assessed for methodological quality using a modified Quality Index. Data were synthesised descriptively. Meta-analysis was not performed as the included studies were not sufficiently homogeneous to provide a meaningful summary. Results Six studies were identified as meeting the eligibility criteria. All studies were laboratory-based and used a repeated measures design. The quality of the studies varied, with Quality Index scores ranging from 7 to 10 out of 14. Five studies investigated foot orthoses and one studied in-shoe wedges. Foot orthoses were found to increase contact area in the midfoot, peak pressures under the hallux and were perceived to provide better arch support, compared to a control. With respect to physiological parameters, contrasting findings have been reported regarding the effect foot orthoses have on oxygen consumption. Further, foot orthoses have been shown to not provide effects on lower limb kinematics and perceived comfort. Both foot orthoses and in-shoe wedges have been shown to provide no effect on power. Conclusion In general, there is limited high-quality research on the effects foot orthoses and in-shoe wedges provide during cycling. At present, there is some evidence that during cycling foot orthoses: increase contact area under the foot and increase

  7. Links Between Displacement Rates and Erosion in Experimental Tectonic Wedges

    NASA Astrophysics Data System (ADS)

    Cruz, L.; Hilley, G.; Take, A.

    2008-12-01

    Erosional redistribution of mass along Earth's surface modifies the near-surface lithostatic stresses, altering displacement rates and the kinematics within orogens. In this study we use analogue experiments of a deforming sand wedge to systematically examine the impact that erosion may have had on the kinematics of the Argentine Precordilleran fold-and-thrust belt at ~32.5°S. Here, the history of deformation has been superbly documented by others, and that work resolves changes in shortening rates over time throughout the range. Specifically, total shortening rates across the fold-and-thrust belt may have changed over time, and out-of-sequence thrusting may have played an important role accommodating deformation at various times in the history of the fold-and-thrust belt. We hypothesize that such changes may be the response of the fold-and-thrust belt to changing erosion of these ranges. To this end, we have constructed an analogue sandbox experiments whose specific layered rheology is akin to that documented in the Precordillera fold-and-thrust belt in central Argentina. Our contractional experimental apparatus (sandbox) includes a servo-controlled feedback system that allows for a variety of boundary conditions to be applied to the moving wall, including constant displacement rate, time-varying displacement rate, constant loading, and time-varying loading. The application of a loading rate allows us to explicitly investigate feedbacks between topographic construction, erosion, strain softening within the dry sand, and temporal changes in total shortening rates that would be difficult to examine using the constant velocity conditions that are usually applied to the analogue models. We also apply Particle Image Velocimetry (PIV) techniques to digital images from the experimental model to derive high-resolution kinematics and calculate strain, uplift and exhumation rates. Preliminary results indicate that changes in the erosional efficiency in the experimental

  8. Microstrip circuit applications of high-Q open microwave resonators

    NASA Astrophysics Data System (ADS)

    Stephan, Karl D.; Young, Song-Lin; Wong, Sai-Chu

    1988-09-01

    An open microwave resonator can be formed above a planar microstrip substrate by suspending a spherical reflector above it. A theory is developed to account for the coupling between such an open resonator mode and a microstrip line. The open resonator is shown to have useful circuit properties similar to a dielectric resonator, but with the potential of efficient operation well into the millimeter-wave range. Experimental confirmation of the theory is demonstrated by a scale model of a microstrip-based single-pole bandpass filter, which shows a loaded Q of 860 and a minimum loss of 0.8 dB +/- 0.4 dB at 10 GHz.

  9. SU-E-T-562: Scanned Percent Depth Dose Curve Discrepancy for Photon Beams with Physical Wedge in Place (Varian IX) Using Different Sensitive Volume Ion Chambers

    SciTech Connect

    Zhao, H; Sarkar, V; Rassiah-Szegedi, P; Huang, Y; Szegedi, M; Huang, L; Salter, B

    2014-06-01

    Purpose: To investigate and report the discrepancy of scanned percent depth dose (PDD) for photon beams with physical wedge in place when using ion chambers with different sensitive volumes. Methods/Materials: PDD curves of open fields and physical wedged fields (15, 30, 45, and 60 degree wedge) were scanned for photon beams (6MV and 10MV, Varian iX) with field size of 5x5 and 10x10 cm using three common scanning chambers with different sensitive volumes - PTW30013 (0.6cm3), PTW23323 (0.1cm3) and Exradin A16 (0.007cm3). The scanning system software used was OmniPro version 6.2, and the scanning water tank was the Scanditronix Wellhoffer RFA 300.The PDD curves from the three chambers were compared. Results: Scanned PDD curves of the same energy beams for open fields were almost identical between three chambers, but the wedged fields showed non-trivial differences. The largest differences were observed between chamber PTW30013 and Exradin A16. The differences increased as physical wedge angle increased. The differences also increased with depth, and were more pronounced for 6MV beam. Similar patterns were shown for both 5x5 and 10x10 cm field sizes. For open fields, all PDD values agreed with each other within 1% at 10cm depth and within 1.62% at 20 cm depth. For wedged fields, the difference of PDD values between PTW30013 and A16 reached 4.09% at 10cm depth, and 5.97% at 20 cm depth for 6MV with 60 degree physical wedge. Conclusion: We observed a significant difference in scanned PDD curves of photon beams with physical wedge in place obtained when using different sensitive volume ion chambers. The PDD curves scanned with the smallest sensitive volume ion chamber showed significant difference from larger chamber results, beyond 10cm depth. We believe this to be caused by varying response to beam hardening by the wedges.

  10. Transforming High School Classrooms with Free/Open Source Software: "It's Time for an Open Source Software Revolution"

    ERIC Educational Resources Information Center

    Pfaffman, Jay

    2008-01-01

    Free/Open Source Software (FOSS) applications meet many of the software needs of high school science classrooms. In spite of the availability and quality of FOSS tools, they remain unknown to many teachers and utilized by fewer still. In a world where most software has restrictions on copying and use, FOSS is an anomaly, free to use and to…

  11. Computational analysis of asymmetric water entry of wedge and ship section at constant velocity

    NASA Astrophysics Data System (ADS)

    Rahaman, Md. Mashiur; Ullah, Al Habib; Afroz, Laboni; Shabnam, Sharmin; Sarkar, M. A. Rashid

    2016-07-01

    Water impact problems receive much attention due to their short duration and large unsteady component of hydrodynamic loads. The effect of water entry has several important applications in various aspects of the naval field. Significant attention has been given to various water entry phenomena such as ship slamming, planning hulls, high-speed hydrodynamics of seaplanes, surface-piercing propellers and the interaction of high-speed liquid drops with structural elements. Asymmetric water entry may be caused by various natural phenomena such as weather conditions or strong winds. Since the determination of hydrodynamic impact load plays a vital role in designing safe and effcient vessels, an accurate and reliable prediction method is necessary to investigate asymmetric water entry problems. In this paper, water entry of a two-dimensional wedge and ship section at constant velocity in asymmetric condition will be analysed numerically and the effects of asymmetric impact on the velocity and pressure distribution will be discussed. The finite volume method is employed to solve the dynamic motion of the wedge in two-phase flow. During the water entry, the air and water interface is described implicitly by the volume of fluid (VOF) scheme. The numerical code and method was first validated for symmetric condition by one of the present author is applied for asymmetric wedge and ship section. The free surface, velocity and pressure distribution for asymmetric water entry are investigated and visualized with contour plots at different time steps.

  12. Empirical evidence for two nightside current wedges during substorms

    NASA Astrophysics Data System (ADS)

    Hoffman, R. A.; Gjerloev, J. W.

    2013-12-01

    We present results from a comprehensive statistical study of the ionospheric current system and its coupling to the magnetosphere during classical bulge type substorms. We identified 116 substorms and determined the global ionospheric current system before and during the substorm using the SuperMAG initiative and global auroral images obtained by the Polar VIS Earth camera. The westward electrojet (WEJ) display a distinct latitudinal shift between the pre- and post-midnight region and we find evidence that the two WEJ regions are disconnected. This, and other observational facts, led us to propose a new 3D current system configuration that consists of 2 wedge type systems: a current wedge in the pre-midnight region (substorm current wedge), and another current wedge system in the post-midnight region (oval current wedge). There is some local time overlap between the two systems. The former maps to the region inside the near Earth neutral line and is associated with structured BPS type electron precipitation. The latter maps to the inner magnetosphere and is associated with diffuse electron precipitation. We present results of the statistical study, show typical events, results from Biot-Savart simulations, and discuss the implications for our understanding of the 3D current system associated with substorms.

  13. Casimir effect for a semitransparent wedge and an annular piston

    SciTech Connect

    Milton, Kimball A.; Wagner, Jef; Kirsten, Klaus

    2009-12-15

    We consider the Casimir energy due to a massless scalar field in a geometry of an infinite wedge closed by a Dirichlet circular cylinder, where the wedge is formed by {delta}-function potentials, so-called semitransparent boundaries. A finite expression for the Casimir energy corresponding to the arc and the presence of both semitransparent potentials is obtained, from which the torque on the sidewalls can be derived. The most interesting part of the calculation is the nontrivial nature of the angular mode functions. Numerical results are obtained which are closely analogous to those recently found for a magnetodielectric wedge, with the same speed of light on both sides of the wedge boundaries. Alternative methods are developed for annular regions with radial semitransparent potentials, based on reduced Green's functions for the angular dependence, which allows calculations using the multiple-scattering formalism. Numerical results corresponding to the torque on the radial plates are likewise computed, which generalize those for the wedge geometry. Generally useful formulas for calculating Casimir energies in separable geometries are derived.

  14. Casimir effect for a semitransparent wedge and an annular piston

    NASA Astrophysics Data System (ADS)

    Milton, Kimball A.; Wagner, Jef; Kirsten, Klaus

    2009-12-01

    We consider the Casimir energy due to a massless scalar field in a geometry of an infinite wedge closed by a Dirichlet circular cylinder, where the wedge is formed by δ-function potentials, so-called semitransparent boundaries. A finite expression for the Casimir energy corresponding to the arc and the presence of both semitransparent potentials is obtained, from which the torque on the sidewalls can be derived. The most interesting part of the calculation is the nontrivial nature of the angular mode functions. Numerical results are obtained which are closely analogous to those recently found for a magnetodielectric wedge, with the same speed of light on both sides of the wedge boundaries. Alternative methods are developed for annular regions with radial semitransparent potentials, based on reduced Green’s functions for the angular dependence, which allows calculations using the multiple-scattering formalism. Numerical results corresponding to the torque on the radial plates are likewise computed, which generalize those for the wedge geometry. Generally useful formulas for calculating Casimir energies in separable geometries are derived.

  15. OpenCourseWare Resources for Advanced High School Study

    ERIC Educational Resources Information Center

    Carson, Steve

    2008-01-01

    In 2000, the Massachusetts Institute of Technology (MIT) faculty first proposed putting the course materials from all 1,800 MIT classes online, free of charge. The idea behind MIT OpenCourseWare (OCW) was to use the Internet for more than just distance learning. When MIT began placing the course materials online in 2002 and 2003, the audience…

  16. Openings

    PubMed Central

    Selwyn, Peter A.

    2015-01-01

    Reviewing his clinic patient schedule for the day, a physician reflects on the history of a young woman he has been caring for over the past 9 years. What starts out as a routine visit then turns into a unique opening for communication and connection. A chance glimpse out the window of the exam room leads to a deeper meditation on parenthood, survival, and healing, not only for the patient but also for the physician. How many missed opportunities have we all had, without even realizing it, to allow this kind of fleeting but profound opening? PMID:26195687

  17. Open ISEmeter: An open hardware high-impedance interface for potentiometric detection.

    PubMed

    Salvador, C; Mesa, M S; Durán, E; Alvarez, J L; Carbajo, J; Mozo, J D

    2016-05-01

    In this work, a new open hardware interface based on Arduino to read electromotive force (emf) from potentiometric detectors is presented. The interface has been fully designed with the open code philosophy and all documentation will be accessible on web. The paper describes a comprehensive project including the electronic design, the firmware loaded on Arduino, and the Java-coded graphical user interface to load data in a computer (PC or Mac) for processing. The prototype was tested by measuring the calibration curve of a detector. As detection element, an active poly(vinyl chloride)-based membrane was used, doped with cetyltrimethylammonium dodecylsulphate (CTA(+)-DS(-)). The experimental measures of emf indicate Nernstian behaviour with the CTA(+) content of test solutions, as it was described in the literature, proving the validity of the developed prototype. A comparative analysis of performance was made by using the same chemical detector but changing the measurement instrumentation. PMID:27250474

  18. Disruption and translation of an orogenic wedge by exhumation of large continental ultrahigh pressure terranes: Examples from the Scandinavian Caledonides

    NASA Astrophysics Data System (ADS)

    Cuthbert, S.; Brueckner, H.

    2012-04-01

    Many collisional orogens are cored by extensive metamorphic terranes composed of reworked continental crust that developed high pressure/ultrahigh pressure (HP/UHP) metamorphic assemblages during subduction into the mantle. The return of these large, buoyant masses to shallow crustal levels has a major effect on orogenic architecture. A model is proposed where thrust-dominated accretion of an orogenic wedge during continental subduction is succeeded by stretching and passive transport of the wedge on top of an exhuming UHP terrane. Initial thrusting occurs when cratons collide and one subducts beneath the other into the mantle. The subducted portion of the craton undergoes HP/UHP metamorphism while an accretionary orogenic wedge develops at its junction with the overlying craton. Subsequent exhumation of the HP/UHP portion occurs either by true extension, which pulls it out of the mantle, and/or by buoyancy-driven extrusion, which inserts it along faults between the lower craton and the base of the wedge. In either case, shearing along the top of the exhuming terrane will reverse from foreland-directed thrusting during subduction to hinterlandward normal displacement during exhumation. The latter shear traction stretches the frontal part of the orogenic wedge away from the rearward part and may even detach it, allowing a fragment to be carried passively towards the foreland on the exhuming plate. The length of displacement would be a function of the amount of exhumation of the UHP terrane, and the total displacement of the leading wedge taper could be considerably further than indicated by palinspastic restorations of thrust allochthons alone. The Jotun and Trondheim Nappe Complexes form major allochthon elements of the Caledonide orogenic wedge in southern and central Scandinavia, respectively. We propose the late-stage behaviour of these allochthons was a response to the rise and lateral transport of the underlying HP/UHP Western Gneiss Complex (WGC). During the

  19. Geomorphology, kinematic history, and earthquake behavior of the active Kuwana wedge thrust anticline, central Japan

    NASA Astrophysics Data System (ADS)

    Ishiyama, Tatsuya; Mueller, Karl; Togo, Masami; Okada, Atsumasa; Takemura, Keiji

    2004-12-01

    We combine surface mapping of fault and fold scarps that deform late Quaternary alluvial strata with interpretation of a high-resolution seismic reflection profile to develop a kinematic model and determine fault slip rates for an active blind wedge thrust system that underlies Kuwana anticline in central Japan. Surface fold scarps on Kuwana anticline are closely correlated with narrow fold limbs and angular hinges on the seismic profile that suggest at least ˜1.3 km of fault slip completely consumed by folding in the upper 4 km of the crust. The close coincidence and kinematic link between folded terraces and the underlying thrust geometry indicate that Kuwana anticline has accommodated slip at an average rate of 2.2 ± 0.5 mm/yr on a 27°, west dipping thrust fault since early-middle Pleistocene time. In contrast to classical fault bend folds the fault slip budget in the stacked wedge thrusts also indicates that (1) the fault tip propagated upward at a low rate relative to the accrual of fault slip and (2) fault slip is partly absorbed by numerous bedding plane flexural-slip faults above the tips of wedge thrusts. An historic earthquake that occurred on the Kuwana blind thrust system possibly in A.D. 1586 is shown to have produced coseismic surface deformation above the doubly vergent wedge tip. Structural analyses of Kuwana anticline coupled with tectonic geomorphology at 103-105 years timescales illustrate the significance of active folds as indicators of slip on underlying blind thrust faults and thus their otherwise inaccessible seismic hazards.

  20. Extension of a double-wedged orogen potentially leads to the current South China Sea

    NASA Astrophysics Data System (ADS)

    Wu, G.; Lavier, L. L.

    2015-12-01

    The South China Sea (SCS) is surrounded by South China on the NW, Palawan and Reed Bank on the SE, as well as several microplates, resembling a jigsaw puzzle. In an attempt to better understand its evolution, we designed simplified thermomechanical models to simulate extension of a double-wedge-shaped orogen with highlands on both sides and lowland in the center to mimic the geological condition of the proto-SCS. We imposed constant extension rates on both sides and Gaussian-shaped thermal impulse in the center. We also varied the strength of lower crust but did not explicitly incorporate mid-ocean ridges and searfloor spreading mechanisms. We currently used symmetric double-wedge, but further tests are planed for asymmetric double-wedges. Our preliminary results show that the models produced many structures that resemble those of SCS, such as 1) a series of domino or conjugate faults sitting above a subsurface detachment (or décollement), 2) exhumed domes of middle-lower crust, 3) extreme thinning of both upper crust and lower crust, and 4) propagation of extension towards NW and SE margins. Our models suggest that superimposition of these modeled characteristics produced during several phases of extension of the SCS that may be due to thermal impulsion, magmatic events, and subduction related relaxation potentially produces high resemblance of the SCS.

  1. An experimental study of shock wave reflection over non-Newtonian liquid wedges

    NASA Astrophysics Data System (ADS)

    Jeon, Hongjoo; Dougherty, Christopher; Miller, Ryan; Eliasson, Veronica

    2014-11-01

    An experimental investigation of the reflection of a planar shock wave over different density liquid wedges was performed by means of an angled shock tube. The goal is to find a transition criterion between regular reflection (RR) and irregular reflection (IR). The shock tube can be rotated to any angle between the horizontal and vertical planes for various impact media. The reflection of the oblique shock wave for different wedges was visualized using the shadowgraph and schlieren techniques. Previous research by Ben-Dor et al. (1987) conducted different types of reflecting solid conditions and Takayama et al. (1989) investigated a similar experiment with a nonsolid reflecting surface. Motivated by the previous work, we undertook a series of shock tube experiments where both Newtonian and non-Newtonian liquids were used to form a wedge for a shock wave to impact. Shear-thickening materials, such as a water-cornstarch mixture, or similar suspensions, could potentially be utilized to protect soldiers and other high-risk personnel from impacts. Results show that, for both a water-cornstarch and ballistic gelatin sample, the detachment angle at which the RR transitions to an IR was different from those of a solid and water. This work is funded by NSF Grant #CBET-1437412.

  2. Continuous beam divergence control via wedge-pair for laser communication applications

    NASA Astrophysics Data System (ADS)

    Hinrichs, Keith M.; DeCew, Alan E.; Narkewich, Lawrence E.; Williams, Timothy H.

    2015-03-01

    Lasercom terminals often scan an area of uncertainty during acquisition with a wide-divergence beacon beam. Once the terminal has established cooperative tracking with the remote terminal, a narrow divergence beam is used for communication. A mechanism that enables continuous beam divergence control can provide significant size, weight, and power (SWaP) benefits to the terminal. First, the acquisition and the communication beams can be launched from the same fiber so only a single high-power optical amplifier is required. Second, by providing mid-divergences, it eases the remote terminal's transition from the acquisition phase to the communication phase. This paper describes a mechanism that provides gradual, progressive adjustment of far-field beam divergence, from wide divergence (> 300 μrad FWHM) through collimated condition (38 μrad FWHM) and that works over a range of wavelengths. The mechanism is comprised of a variable-thickness optical element, formed by a pair of opposing wedges that is placed between the launch fiber and the collimating lens. Variations in divergence with no beam blockage are created by laterally translating one wedge relative to a fixed wedge. Divergence is continuously adjustable within the thickness range, allowing for a coordinated transition of divergence, wavelength, and beam power. Measurements of this low-loss, low-wavefront error assembly show that boresight error during divergence transition is maintained to a fraction of the communication beamwidth over wavelength and optical power ranges.

  3. An analysis of scattering from a reentrant wedge

    NASA Astrophysics Data System (ADS)

    Bhatta, Ambika

    In this thesis the scattering of acoustic pressure from a rigid wedge is examined. The wedges having re-entrant geometry are of particular interest. The incident field is considered from a time harmonic point source. The solution for the scattered pressure field is obtained by modal, image and asymptotic analysis. It is numerically shown that the exact modal solution and image based solution for different incident frequencies and source positions are the same. It is also shown that the asymptotic solution obtained matches with the image based solution.

  4. Transient and Steady-State Kinematic Response to Erosional Forcing in an Orogenic Wedge: Sandbox Perspective

    NASA Astrophysics Data System (ADS)

    Cruz, L.; Teyssier, C.; Annia, F.; Take, A.

    2005-12-01

    The evolution of orogens is highly affected by surface processes that control mass distribution. Transportation and redistribution of mass at the Earth's surface modifies the gravitational load and alters the stress field and kinematics within orogens. We explore the role of asymmetric erosion, indenter dip angle, and flux steady/non-steady state in determining the patterns of deformation and exhumation in doubly-sided orogenic wedges. In our analogue model, shortening of the orogen is driven by rigid indenters, represented by Plexiglas wedged blocks (35 and 70 degrees) that deform a non-cohesive dry Coulomb material (walnut shells) representing crustal material. Three end-member erosional scenarios are considered. In the first case, erosion is not applied, and thus the doubly-sided orogenic wedge evolves without restraints (non-steady state). In the second case, erosion is concentrated solely on the indenters side of the orogen (retrowedge), and in the third case, erosion is focused on the flank opposite to the indenter side (prowedge). In the last two cases, steady-state conditions were present in the middle stages of shortening. Strain and exhumation were calculated using displacement fields from 2D particle image velocimetry (PIV analysis). In the three cases, the model deforms as a combination of lateral compaction and localization of strain in shear bands. In the early stages of deformation, a "pop-up" structure develops, bounded by a fore-shear on the front and a back-shear toward the indenter. As deformation continues, a new fore-shear develops, and the previous one remains inactive and is passively pushed up the wedge. In the case of no erosion, the old fore-shears rotate slightly toward the indenter, and the shear bands evolve to steeply dipping structures. In the case of retrowedge erosion, the old fore-shears back rotate toward the indenter, and the shear bands evolve to shallowly dipping structures. In the case of prowedge erosion, old fore

  5. Flow bursts, breakup arc, and substorm current wedge

    NASA Astrophysics Data System (ADS)

    Haerendel, Gerhard

    2015-04-01

    Energy liberated by the reconnection process in the near-Earth tail is transported via flow bursts toward the dipolar magnetosphere during substorms. The breakup arc is a manifestation of the arrival of the bursts under flow braking and energy deposition. Its structure and behavior is analyzed on the basis of five striking spatial, temporal, and energetic properties, qualitatively and in part also quantitatively. A key element is the formation of stop layers. They are thin layers, of the width of an ion gyro radius, in which the magnetic field makes a transition from tail to near-dipolar magnetosphere configurations and in which the kinetic energy of fast flows is converted into electromagnetic energy of kinetic Alfvén waves. The flows arise from the relaxation of the strong magnetic shear stresses in the leading part of the flow bursts. The bright narrow arcs of less than 10 km width inside the broad poleward expanding breakup arc, Alfvénic in nature and visually characterized by erratic short-lived rays, are seen as traces of the stop layers. The gaps between two narrow and highly structured arcs are filled with more diffuse emissions. They are attributed to the relaxation of the less strained magnetic field of the flow bursts. Eastward flows along the arcs are linked to the shrinking gaps between two successive arcs and the entry of auroral streamers into the dipolar magnetosphere in the midnight sector. Flow braking in the stop layers forms multiple pairs of narrow balanced currents and cannot be behind the formation of the substorm current wedge. Instead, its origin is attributed to the force exerted by the dipolarized magnetic field of the flow bursts on the high-beta plasma, after the high magnetic shears have relaxed and the fast flows and stop layer process have subsided, in other words, to the "dying flow bursts."

  6. Biomechanical effects of plate area and locking screw on medial open tibial osteotomy.

    PubMed

    Luo, Chu-An; Lin, Shang-Chih; Hwa, Su-Yang; Chen, Chun-Ming; Tseng, Ching-Shiow

    2015-01-01

    Medial open high tibial osteotomy (HTO) has been used to treat osteoarthritis of the medial compartment of the knee. However, weaker plate strength, unstable plate/screw junction and improper surgery technique are highly related to the HTO outcomes. Two π-shape plates were designed and eight variations (two supporting area × four locking stiffness) were compared by finite-element method. The computed tomography-based tibia was reconstructed and both wedge micromotion and implant stresses were chosen as the comparison indices. The construct was subjected to surgical and physiological loads. The medial-posterior region is the most loaded region and the load through the posterior leg is about four times that through the anterior leg. This indicates that the two-leg design can form a force-couple mechanism to effectively reduce the implant stresses. The use of locking screws significantly decrease the screw and hole stresses. However, the extending plate reduces the stresses of screws and holes above the wedge but makes the distal screws and holes much stressed. Wedge micromotion is affected by extending plate rather than locking screw. Three factors contribute to effective stabilisation of unstable HTO wedge: (1) intimate tibia-plate contact at medial-posterior regions, (2) sufficient rigidity at plate-screw junctions and (3) effective moment-balancing design at distal tibia-plate interfaces.

  7. The Superimposed Paleocene-Miocene Tectonics of the middle part of the Nallihan Wedge (NW Turkey)

    NASA Astrophysics Data System (ADS)

    Şahin, Murat; Yaltirak, Cenk

    2015-04-01

    In the NW Turkey, the area between the suture zones of the Rhodope-Pontide Ocean and Izmir-Ankara Ocean, and North Anatolian Fault Zone (NAFZ) and Thrace-Eskişehir Fault Zone (TEFZ) is known as the Nallıhan Wedge. The shape of Nallıhan Wedge is a 90 degree counter-clockwise rotated isosceles triangle. The northwestern boundary is a part of NAFZ and the southwestern boundary is a part of TEFZ. The 160 km-long eastern boundary is located at around Beypazarı and western corner is on the Bursa Plain. Nallıhan is situated at the centre of this isosceles triangle. While all the thrusts and folds shrink towards to the west and show an imbricate-like structure, the characteristics of the folds turn into to the open folds. Thrusts faults are locally observed as blind and almost perpendicular thrusts at the fold limbs towards to the east. The rocks of the study area show different characteristics according to their types and basins of formation. On the other hand the structural properties of these rocks display the effects of the closure of the Intra-Pontide and Izmir-Ankara Oceans in between Paleocene and Early Oligocene. During Miocene, the thrust faults reactivated and a deformation formed the NEE-SWW left lateral strike-slip faults parallel to these thrust faults. Whereas the first events are related to the closure of the branches of Neo-Tethys, the Miocene deformation is probably based on the Miocene tectonics of the Western Anatolia by the reason of equivalent age of the TEFZ. In this framework, the deformation of the Nallıhan Wedge presents significant information about the period between the evolution of Paleotectonic and Neotectonic of Turkey.

  8. Commissioning of motorized wedge for the first equinox-80 telecobalt unit and implementation in the Eclipse 3D treatment planning system.

    PubMed

    Kinhikar, R A; Sharma, S; Upreti, R; Tambe, C M; Deshpande, D D; Shrivastava, S K; Dinshaw, K A

    2007-06-01

    A new model of the telecobalt unit (TCU), Theratron Equinox-80, (MDS Nordion, Canada) equipped with a single 60 degree motorized wedge (MW), four universal wedges (UW) for 15 degrees, 30 degrees, 45 degrees and 60 degrees have been evaluated. MW was commissioned in Eclipse (Varian, Palo Alto, USA) 3D treatment planning system (TPS). The profiles and central axis depth doses (CADD) were measured with Wellhofer blue water phantom for MW and the measured data was commissioned in Eclipse. These profiles and CADD for MW were compared with UW in a homogeneous phantom generated in Eclipse for various field sizes. The dose was also calculated in the same phantom at 10 cm depth. For the particular MW angle and the respective open and MW beam weights, the dose was measured for a field size of 10 cm x 10 cm in a MEDTEC water phantom at 10 cm depth with a 0.13 cc thimble ion chamber (Scanditronix Wellhofer, Uppsala, Sweden) and a NE electrometer (Nuclear Enterprises, UK). Measured dose with ion chamber was compared with the TPS calculated dose. MW angle verification was also done on the Equinox for four angles (15 degrees, 30 degrees, 45 degrees and 60 degrees). The variation in measured and calculated dose at 10 cm depth was within 2%. The measured and the calculated wedge angles were in good agreement within 2 degrees. The motorized wedges were successfully commissioned in Eclipse for four wedge angles. PMID:17682402

  9. Articulated open nozzle high pressure unit fuel injector

    SciTech Connect

    Perr, J.P.

    1991-12-31

    This patent describes an open nozzle unit fuel injector for use in an internal combustion engine of the type having a drive train associated with each unit injector to synchronously control each unit injector. It comprises an injector body having an axial bore open from an end of the injector body and at least one injection orifice passing through a tip of the cup from the axial bore, a plunger assembly reciprocably movably disposed within the axial bore for movement between a retracted position and an advanced position under the influence of a drive train to be associated with the unit fuel injector, the plunger assembly including a plunger, an articulated tip, a connection means for connecting the articulated tip to the plunger while permitting axial movement therebetween and for allowing pressure of a trapped volume of fuel between the plunger and the articulated tip to hold the articulated tip in a closed position following termination of an injection event so as to avoid secondary injection, and a means for absorbing an over-travel imparted to the plunger by the associated drive train such that the pressure of the trapped volume of fuel is regulated without the provision of means for spilling the trapped volume, whereby the articulated tip does not experience the over-travel.

  10. Rise of a variable-viscosity fluid in a steadily spreading wedge-shaped conduit with accreting walls

    USGS Publications Warehouse

    Lachenbruch, Arthur H.; Nathenson, Manuel

    1976-01-01

    Relatively rigid plates making up the outer 50 to 100 km of the Earth are steadily separating from one another along narrow globe-circling zones of submarine volcanism, the oceanic spreading centers. Continuity requires that the viscous underlying material rise beneath spreading centers and accrete onto the steadily diverging plates. It is likely that during the rise the viscosity changes systematically and that the viscous tractions exerted on the plates contribute to the unique pattern of submarine mountains and earthquake faults observed at spreading centers. The process is modeled by viscous creep in a wedge-shaped conduit (with apex at the sea floor) in which the viscosity varies as rm where r is distance from the apex and m is a parameter. For these conditions, the governing differential equations take a simple form. The solution for the velocity is independent of r and of the sign of m. As viscous stresses vary as rm-1, the pattern of stress on the conduit wall is sensitive to viscosity variation. For negative m, the viscous pressure along the base of the conduit is quite uniform; for positive m, it falls toward zero in the axial region as the conduit base widens. For small opening angles, viscous forces push the plates apart, and for large ones, they oppose plate separation. Though highly idealized, the solution provides a tool for investigating tectonic processes at spreading centers.

  11. Evolution of Strain in Obliquely Convergent Analog Doubly-Vergent Wedges

    NASA Astrophysics Data System (ADS)

    Davis, D. M.; Haq, S. S.

    2012-12-01

    We have conducted a range of analog experiments across the parameter space from 0° to 70°, in which we have tracked the evolution of the model geometries and strain fields. Surface deformation is monitored by photographic analysis of the experiment and a plane laser is used to obtain precise topography of the developing pro and retro-wedges normal to strike At both high and low obliquities, our results are broadly consistent with theoretical expectations. At obliquities ranging from 0° to close to 60°, doubly-vergent wedges with the same combination of a broad, minimum taper pro-wedge and a narrower, maximum-taper double retro-wedge found in normal convergence at obliquities up to close to 60°. Above about 60° obliquity, though, the orogen continues to grow with a much greater degree of symmetry; it never develops the broad prowedge that characterizes the orogens at low to moderately high obliquities. This result is entirely consistent with the rotation of stresses and reversal in principal stress order associated with the transition from an essentially convergent orogen with some margin-parallel shear to transpression with dominant strike-slip, as described by various authors. This marked change in tectonic style and orogen shape at about 60° obliquity is accompanied by a change in the distribution of shear within the model. In normal convergence, there is no margin-parallel shear to be accommodated, so it is everywhere equal to zero. Margin-normal shortening is accommodated across the orogen, but, as taper is maintained, it occurs most rapidly near the deformation front (at left). In no case is there extension in these purely frictional models, unlike the case with a ductile layer at depth. At non-zero obliquities, there is also margin-parallel shear to be distributed across the margin. In addition to a broad zone centered on the topographic high (over the tip of the backstop), that shear is distributed across the prowedge, where it is accommodated in the

  12. Flowfield Establishment and Unsteadiness in Hypervelocity Double Wedge Flows

    NASA Astrophysics Data System (ADS)

    Swantek, A. B.; Knisely, A. M.; Austin, J. M.

    Significant discrepancies between experiments and simulations have been reported in the normalized establishment times for hypervelocity double wedge and double cone flows. Experimental results for flow establishment times based on heat transfer measurements have been reported by Holden and Mallinson, Gai, and Mudford [1, 2].

  13. Magnetic and structural instabilities of ultrathin Fe(100) wedges

    SciTech Connect

    Bader, S.D.; Li, Dongqi; Qiu, Z.Q.

    1994-05-01

    An overview is provided of recent efforts to explore magnetic and related structural issues for ultrathin Fe films grown epitaxially as wedge structures onto Ag(100) and Cu(100). Experiments were carried out utilizing the surface magneto-optic Kerr effect (SMOKE). Ordinary bcc Fe is lattice-matched to the primitive unit cell of the Ag(100) surface. Fe wedges on Ag(100) can be fabricated whose thick end has in-plane magnetic easy axes due to the shape anisotropy, and whose thin end has perpendicular easy axes due to the surface magnetic anisotrophy. A spin-reorientation transition can thus be studied in the center of the wedge where the competing anisotropies cancel. The goal is to test the Mermin-Wagner theorem which states that long-range order is lost at finite temperatures in an isotropic two-dimensional Heisenberg system. Fe wedges on Cu(100) can be studied in like manner, but the lattice matching permits fcc and tetragonally-distorted fcc phases to provide structural complexity in addition to the interplay of competing magnetic anisotropies. The results of these studies are new phase identifications that help both to put previous work into perspective and to define issues to pursue in the future.

  14. Thrusting and wedge growth, Southern Alps of Lombardia (Italy)

    NASA Astrophysics Data System (ADS)

    Roeder, Dietrich

    1992-06-01

    A south-vergent fold-thrust belt of Miocene-Recent age accompanies the south slope of the Lombardian Alps and is partly buried beneath Plio-Pleistocene Po Valley basin fill. The belt is probably detached along a trans-crustal thrust, named Main South Alpine Thrust (MSAT), with an estimated dip slip of 70-100 km. Transport on this thrust piggybacks the Adamello pluton of Late Eocene age, pre-Adamello folds, and Oligocene-Miocene Insubric strike-slip structures, by ramping up through 12-15 km of Austro-Alpine (Adria) crust and through 8-10 km of Triassic to Eocene sediments. Folds in the Front Ranges are ascribed to MSAT ramping, not to pre-Adamello compression. The MSAT soles upward in a blind thrust beneath 3-4 km of Oligocene-Pliocene foredeep fill. Initial regional failure along the MSAT implies substantial and pre-existing topographic relief near the Insubric line. An average of 25% wedge thickening during MSAT transport is consistent with the requirement of Coulomb critical taper. Progression of the south-Alpine detachment from the MSAT to the base of the foreland sediments has added a thickness of 6-12 km in footwall imbrications to the base and the toe of the thrust wedge. This addition in wedge volume is consistent with wedge dynamics only if a mid-Miocene or younger spike of excess Alpine topography is admitted.

  15. How important is randomisation in a stepped wedge trial?

    PubMed

    Hargreaves, James R; Prost, Audrey; Fielding, Katherine L; Copas, Andrew J

    2015-01-01

    In cluster randomised trials, randomisation increases internal study validity. If enough clusters are randomised, an unadjusted analysis should be unbiased. If a smaller number of clusters are included, stratified or matched randomisation can increase comparability between trial arms. In addition, an adjusted analysis may be required; nevertheless, randomisation removes the possibility for systematically biased allocation and increases transparency. In stepped wedge trials, clusters are randomised to receive an intervention at different start times ('steps'), and all clusters eventually receive it. In a recent study protocol for a 'modified stepped wedge trial', the investigators considered randomisation of the clusters (hospital wards), but decided against it for ethical and logistical reasons, and under the assumption that it would not add much to the rigour of the evaluation. We show that the benefits of randomisation for cluster randomised trials also apply to stepped wedge trials. The biggest additional issue for stepped wedge trials in relation to parallel cluster randomised trials is the need to control for secular trends in the outcome. Analysis of stepped wedge trials can in theory be based on 'horizontal' or 'vertical' comparisons. Horizontal comparisons are based on measurements taken before and after the intervention is introduced in each cluster, and are unbiased if there are no secular trends. Vertical comparisons are based on outcome measurements from clusters that have switched to the intervention condition and those from clusters that have yet to switch, and are unbiased under randomisation since at any time point, which clusters are in intervention and control conditions will have been determined at random. Secular outcome trends are a possibility in many settings. Many stepped wedge trials are analysed with a mixed model, including a random effect for cluster and fixed effects for time period to account for secular trends, thereby combining both

  16. Formation of high overburden dumps in open-casts

    SciTech Connect

    S.G. Molotilov; V.K. Norri

    2007-09-15

    The specificity of formation of high overburden dumps in opencast excavations and ravines is considered. It is proposed to exercise high dumping and deformation control in piled rocks by using a new dumping complex supporting high efficiency and safety of dumping operations.

  17. Computation of the seismic stability of rock wedges

    NASA Astrophysics Data System (ADS)

    Ghosh, A.; Haupt, W.

    1989-04-01

    Newmark's concept of computing the permanent displacement under seismic loads has been combined with the conventional limit equilibrium analysis to compute the displacements of a rock wedge. The rock wedge formed by the intersecting planes may or may not have a tension crack in the upper slope surface. As the static analysis of a rock wedge is available from the literature, only the seismic problem is treated theoretically in more details. A computer program has been developed to compute the displacements from the digitised input data of the acceleration-time-history. The program can take into account the water pressure on the intersecting planes and on the planes of the tension crack. The effect of rock anchors if present is also taken care of in addition to static surcharge loads. The program calculates the conventional static factor of safety, remaining resistance against sliding, the critical acceleration, exciting force, relative velocity with time and the cumulative displacements. Two model examples are presented: one with simple sinusoidal acceleration and the other one with actual earthquake data considering the different systems of forces acting on the wedge. The results are critically discussed with respect to the different parameters e. g. anchor forces, water pressure and cohesion influencing the magnitude of displacements under seismic loads. It is shown that the critical acceleration is a better index for the seismic stability than the conventional factor of safety. The critical acceleration presented in this paper serves as a very handy tool for a site engineer to get the first hand information about the stability of the wedge for a given acceleration-time-history without going into the details of dynamic analysis.

  18. Investigation of Acoustical Shielding by a Wedge-Shaped Airframe

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.; Clark, Lorenzo R.; Dunn, Mark H.; Tweed, John

    2004-01-01

    Experiments on a scale model of an advanced unconventional subsonic transport concept, the Blended Wing Body (BWB), have demonstrated significant shielding of inlet-radiated noise. A computational model of the shielding mechanism has been developed using a combination of boundary integral equation method (BIEM) and equivalent source method (ESM). The computation models the incident sound from a point source in a nacelle and determines the scattered sound field. In this way the sound fields with and without the airfoil can be estimated for comparison to experiment. An experimental test bed using a simplified wedge-shape airfoil and a broadband point noise source in a simulated nacelle has been developed for the purposes of verifying the analytical model and also to study the effect of engine nacelle placement on shielding. The experimental study is conducted in the Anechoic Noise Research Facility at NASA Langley Research Center. The analytic and experimental results are compared at 6300 and 8000 Hz. These frequencies correspond to approximately 150 Hz on the full scale aircraft. Comparison between the experimental and analytic results is quite good, not only for the noise scattering by the airframe, but also for the total sound pressure in the far field. Many of the details of the sound field that the analytic model predicts are seen or indicated in the experiment, within the spatial resolution limitations of the experiment. Changing nacelle location produces comparable changes in noise shielding contours evaluated analytically and experimentally. Future work in the project will be enhancement of the analytic model to extend the analysis to higher frequencies corresponding to the blade passage frequency of the high bypass ratio ducted fan engines that are expected to power the BWB.

  19. Investigation of Acoustical Shielding by a Wedge-Shaped Airframe

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.; Clark, Lorenzo R.; Dunn, Mark H.; Tweed, John

    2006-01-01

    Experiments on a scale model of an advanced unconventional subsonic transport concept, the Blended Wing Body (BWB), have demonstrated significant shielding of inlet-radiated noise. A computational model of the shielding mechanism has been developed using a combination of boundary integral equation method (BIEM) and equivalent source method (ESM). The computation models the incident sound from a point source in a nacelle and determines the scattered sound field. In this way the sound fields with and without the airfoil can be estimated for comparison to experiment. An experimental test bed using a simplified wedge-shape airfoil and a broadband point noise source in a simulated nacelle has been developed for the purposes of verifying the analytical model and also to study the effect of engine nacelle placement on shielding. The experimental study is conducted in the Anechoic Noise Research Facility at NASA Langley Research Center. The analytic and experimental results are compared at 6300 and 8000 Hz. These frequencies correspond to approximately 150 Hz on the full scale aircraft. Comparison between the experimental and analytic results is quite good, not only for the noise scattering by the airframe, but also for the total sound pressure in the far field. Many of the details of the sound field that the analytic model predicts are seen or indicated in the experiment, within the spatial resolution limitations of the experiment. Changing nacelle location produces comparable changes in noise shielding contours evaluated analytically and experimentally. Future work in the project will be enhancement of the analytic model to extend the analysis to higher frequencies corresponding to the blade passage frequency of the high bypass ratio ducted fan engines that are expected to power the BWB.

  20. Degree of serpentinization in the forearc mantle wedge of Kyushu subduction zone: quantitative evaluations from seismic velocity

    NASA Astrophysics Data System (ADS)

    Xia, Shaohong; Sun, Jinlong; Huang, Haibo

    2015-09-01

    Serpentinization is an important phenomenon for understanding the water cycle and geodynamics of subduction zones in the upper mantle. In this study, we evaluate quantitatively the degree of serpentinization using the seismic velocity. The results show that serpentinization mainly occurs in the forearc mantle wedge along the subducted oceanic crust, and the degree of serpentinization in the forearc mantle wedge of Kyushu is strongly heterogeneous and varies from 0 to 12 %, containing about 0-1.8 % water contents. In general, the degree of serpentinization gradually decreases with depth from 40 to 80 km and the largest degree usually occur in about 40-50 km depth. Localized high anomalies of serpentinization are revealed in the northern and southern portions of Kyushu, respectively. We suggest that in the northern portion of the forearc mantle wedge, the water contents are relatively large, which might result from the abundant fractures and cracks with more fluids in the subducting slab because of the subduction of Kyushu-Palau ridge and the sudden change in its subduction angle of Philippine Sea lithosphere. But the high degree of serpentinization in the southern portion is closely associated with the active left-lateral shear zone revealed by global positioning system site velocities and earthquake focal mechanisms. In addition, the present results also display that the low degree of serpentinization in the central domain of the forearc mantle wedge is consistent with the location of anomalous arc volcano. The distribution of water contents is closely associated with the degree of serpentinization in the forearc mantle wedge.

  1. Universal authoring system: Round two: The wedge

    SciTech Connect

    Andrews, A.E.; Spangenberg, L.; Trainor, M.S.

    1988-01-01

    Recent papers in the literature have proposed a universal authoring system. While these papers are valuable because they stimulated debate and provided a baseline, pursuing a universal authoring system at this time is a search for a solution before the requirements and problems have been clearly identified. This paper explores several issues related to the concept of a universal authoring system and concludes with an alternative prescription both for users (customers) and vendors. The user prescription includes a clear definition of requirements and establishment of internal standards. The vendor prescription includes working with the users more closely to aid in system comparison. This task is very difficult now because of nonstandard criteria used by the scores of vendors involved. A model for a /open quotes/universal/close quotes/ authoring system is presented to illustrate that the options are endless. Technical issues regarding difficulties of achieving universality of authoring without restricting progress in hardware. The authors agree that the plethora of authoring systems on the market today inhibits courseware portability, but we feel that our free enterprise system as well as more informed consumers will help reduce the number of surviving authoring systems. 11 refs., 3 figs.

  2. Jane Austen in the High School Classroom (Open to Suggestion).

    ERIC Educational Resources Information Center

    Fritzer, Penelope

    1996-01-01

    Argues that Jane Austen's novels lend themselves to the high school curriculum, and that students will discover a leisurely, rural world in which the concerns of the young people are often similar to theirs. (SR)

  3. Analysis of high-quality modes in open chaotic microcavities

    SciTech Connect

    Fang, W.; Yamilov, A.; Cao, H.

    2005-08-15

    We present a numerical study of the high-quality modes in two-dimensional dielectric stadium microcavities. Although the classical ray mechanics is fully chaotic in a stadium billiard, all of the high-quality modes show a 'strong scar' around unstable periodic orbits. When the deformation (ratio of the length of the straight segments over the diameter of the half circles) is small, the high-quality modes correspond to whispering-gallery-type trajectories and their quality factors decrease monotonically with increasing deformation. At large deformation, each high-quality mode is associated with multiple unstable periodic orbits. Its quality factor changes nonmonotonically with the deformation, and there exists an optimal deformation for each mode at which its quality factor reaches a local maximum. This unusual behavior is attributed to the interference of waves propagating along different constituent orbits that could minimize light leakage out of the cavity.

  4. Electromagnetic sensing for the monitoring of structures and infrastructures: a model for the diffraction by penetrable wedges

    NASA Astrophysics Data System (ADS)

    Riccio, G.; Gennarelli, G.

    2012-04-01

    As well-known, the observation of structures and infrastructures by radar remote sensing involves the investigation of the high-frequency electromagnetic scattering by canonical shapes, such as cylinders and wedges. For instance, the ruptures caused by natural disasters can be represented in the form of a wedge-shaped fracture [1]. They modify the electromagnetic response of the scene under investigation and the Geometrical Theory of Diffraction (GTD) can be used as efficient tool for describing this occurrence. Diffraction by a wedge is a well-covered topic in the scientific literature, but the available results mainly concern impenetrable structures. The aim of this work is to provide Uniform Asymptotic Physical Optics (UAPO) diffraction coefficients in the case of lossless penetrable wedges illuminated by plane waves having normal incidence with respect to the edge. To this end, the original problem is subdivided into two parts relevant to the internal region of the wedge and the surrounding space. For what concerns the evaluation of the field diffracted in the outer region, equivalent electric and magnetic PO surface currents are used as sources in the radiation integral. They lie on the external faces of the wedge and their expressions change in accordance with the incidence direction. As a matter of fact, they involve the reflection and transmission Fresnel's coefficients when one external face is directly illuminated, and only the reflection Fresnel's coefficients if both the external faces are considered. A useful approximation and a uniform asymptotic evaluation of the resulting radiation integrals allow one to obtain the diffraction coefficients in terms of the Geometrical Optics (GO) response and the standard transition function of the Uniform Theory of Diffraction (UTD) [2]. The evaluation of the field diffracted in the inner region is tackled and solved by using equivalent PO surface currents on the internal faces of the wedge. Once such currents are

  5. Experimental investigation of sound absorption of acoustic wedges for anechoic chambers

    NASA Astrophysics Data System (ADS)

    Belyaev, I. V.; Golubev, A. Yu.; Zverev, A. Ya.; Makashov, S. Yu.; Palchikovskiy, V. V.; Sobolev, A. F.; Chernykh, V. V.

    2015-09-01

    The results of measuring the sound absorption by acoustic wedges, which were performed in AC-3 and AC-11 reverberation chambers at the Central Aerohydrodynamic Institute (TsAGI), are presented. Wedges of different densities manufactured from superfine basaltic and thin mineral fibers were investigated. The results of tests of these wedges were compared to the sound absorption of wedges of the operating AC-2 anechoic facility at TsAGI. It is shown that basaltic-fiber wedges have better sound-absorption characteristics than the investigated analogs and can be recommended for facing anechoic facilities under construction.

  6. Making High School Work: Lessons from the Open School.

    ERIC Educational Resources Information Center

    Gregory, Tom

    Adolescents have a strong need to feel that they belong. This book relates the story of a nontraditional high school, at which the author was a part-time staff member during the 1987-88 academic year. Data were gathered from participant observation and from interviews with 23 teachers and staff members, 42 students, and 6 educational…

  7. [Sensitometry of Mammographic Screen-film System Using Bootstrap Aluminum Step-Wedge.].

    PubMed

    Abe, Shinji; Imada, Ryou; Terauchi, Takashi; Fujisaki, Tatsuya; Monma, Masahiko; Nishimura, Katsuyuki; Saitoh, Hidetoshi; Mochizuki, Yasuo

    2005-01-01

    Recently, a few types of step-wedges for bootstrap sensitometry with a mammographic screen-film system have been proposed. In this study, the bootstrap sensitometry with the mammographic screen-film system was studied for two types of aluminum step-wedges. Characteristic X-ray energy curves were determined using mammographic and general radiographic aluminum step-wedges devised to prevent scattered X-rays generated from one step penetrating into the region of another one, and dependence of the characteristic curves on the wedges was also discussed. No difference was found in the characteristic curves due to the difference in the step-wedges for mammography and general radiography although there was a slight difference in shape at the shoulder portion for the two types of step-wedges. Therefore, it was concluded that aluminum step-wedges for mammography and general radiography could be employed in bootstrap sensitometry with the mammographic screen-film system. PMID:16479054

  8. Mechanism of Hot Finger Formation in Mantle Wedge

    NASA Astrophysics Data System (ADS)

    Matsuo, M. Y.; Tamura, Y.; Sakaguchi, H.

    2013-12-01

    Processes of mantle melting and volcanic eruptions along subduction zones are often illustrated by the use of two-dimensional cross-section models of convergent margins. However, Quaternary volcanoes in the NE Japan arc could be grouped into ten volcano clusters striking transverse to the arc; these have an average width of ~ 50 km, and are separated by parallel gaps 30-75 km wide (Tamura et al., 2002). Moreover, the structure of the mantle wedge and arc crust beneath the NE Japan arc and the Izu-Bonin-Mariana arc, respectively, suggest that the third dimension, lying along the strike of the arc, is necessary to understand the actual production of magmas in subduction zones (e.g., Nakajima et al., 2001; Hasegawa & Nakajima, 2004; Kodaira et al., 2007; Kodaira et al., 2008). Common periodic structural variations, having wavelengths of 80-100 km, can be observed in both areas. This grouping of volcanoes and the structural variations may be related to locally developed hot regions within the mantle wedge that have the form of inclined, 50 km-wide fingers (hot fingers). The 'hot fingers' models (Tamura et al., 2002) may play an important role in linking the 3D structures within the mantle wedge and overlying arc crust to volcanic eruptions at the surface. To explore a physical and mathematical mechanism to produce a hot finger pattern, we develop a hydrodynamic model of mantle convection in mantle wedge. A hypothesis incorporated in our model is a double diffusive mechanism of mantle materials; diffusion of composition of mantle materials is much weaker than temperature diffusion. We show that our model shows a spatiotemporal pattern in a mantle material composition, temperature, and velocity that are similar to the spatiotemporal patterns observed in the NE Japan arc.

  9. Modal Analysis in Lined Wedge-Shaped Ducts

    NASA Astrophysics Data System (ADS)

    Mechel, F. P.

    1998-10-01

    It has been suggested to describe the sound field in a wedge-shaped duct in a cylindrical co-ordinate system in which the boundaries of the wedge lie in a co-ordinate surface. This suggestion was developed in a companion paper [1]. The wave equation can be separated only if the boundaries are ideally reflecting (rigid or soft). Two solutions were proposed in reference [1] for absorbing boundaries. In the first solution the sound field is composed of “ideal modes” (modes in a wedge with ideally reflecting boundaries); the boundary condition at the absorbing boundary then leads to a system of equations for the mode amplitudes. The problem with this method lies in the fact that there is no radial orthogonality of the ideal modes so that the precision of the field synthesis by ideal modes is doubtful. In the second method in reference [1] one defines “fictitious modes” which satisfy the boundary conditions at the flanks exactly and which are based on hypergeometric functions as radial functions, but which produce a “rest” in the wave equation. It was described how this rest can be minimized; this procedure leads to slow numerical integrations. In the present paper, the wedge is subdivided into duct sections with parallel walls (the boundary is stepped); the fields in the sections are composed of duct modes (modes in a straight lined duct); the mode amplitudes are determined from the boundary conditions at the section limits. The advantages of the present method are (analytically) the duct modes are orthogonal across the sections, so the mode amplitudes can be determined with the usual precision of a modal analysis, and (numerically) no numerical integrations are needed.

  10. Distribution of lithium in the Cordilleran Mantle wedge

    NASA Astrophysics Data System (ADS)

    Shervais, J. W.; Jean, M. M.; Seitz, H. M.

    2015-12-01

    Enriched fluid-mobile element (i.e., B, Li, Be) concentrations in peridotites from the Coast Range ophiolite are compelling evidence that this ophiolite originated in a subduction environment. A new method presented in Shervais and Jean (2012) for modeling the fluid enrichment process, represents the total addition of material to the mantle wedge source region and can be applied to any refractory mantle peridotite that has been modified by melt extraction and/or metasomatism. Although the end-result is attributed to an added flux of aqueous fluid or fluid-rich melt phase derived from the subducting slab, in the range of tens of parts per million - the nature and composition of this fluid could not be constrained. To address fluid(s) origins, we have analyzed Li isotopes in bulk rock peridotite and eclogite, and garnet separates, to identify possible sources, and fluid flow mechanisms and pathways. Bulk rock Li abundances of CRO peridotites (δ7Li = -14.3 to 5.5‰; 1.9-7.5 ppm) are indicative of Li addition and δ7Li-values are lighter than normal upper mantle values. However, Li abundances of clino- and orthopyroxene appear to record different processes operating during the CRO-mantle evolution. Low Li abundances in orthopyroxene (<1 ppm) suggest depletion via partial melting, whereas high concentrations in clinopyroxenes (>2 ppm) record subsequent interaction with Li-enriched fluids (or melts). The preferential partitioning of lithium in clinopyroxene could be indicative of a particular metasomatic agent, e.g., fluids from a dehydrating slab. Future in-situ peridotite isotope studies via laser ablation will further elucidate the fractionation of lithium between orthopyroxene, clinopyroxene, and serpentine. To obtain a more complete picture of the slab to arc transfer processes, we also measured eclogites and garnet separates to δ7Li= -18 to 3.5‰ (11.5-32.5 ppm) and δ7Li= 1.9 to 11.7‰ (0.7-3.9 ppm), respectively. In connection with previous studies focused

  11. On the acoustic wedge design and simulation of anechoic chamber

    NASA Astrophysics Data System (ADS)

    Jiang, Changyong; Zhang, Shangyu; Huang, Lixi

    2016-10-01

    This study proposes an alternative to the classic wedge design for anechoic chambers, which is the uniform-then-gradient, flat-wall (UGFW) structure. The working mechanisms of the proposed structure and the traditional wedge are analyzed. It is found that their absorption patterns are different. The parameters of both structures are optimized for achieving minimum absorber depth, under the condition of absorbing 99% of normal incident sound energy. It is found that, the UGFW structure achieves a smaller total depth for the cut-off frequencies ranging from 100 Hz to 250 Hz. This paper also proposes a modification for the complex source image (CSI) model for the empirical simulation of anechoic chambers, originally proposed by Bonfiglio et al. [J. Acoust. Soc. Am. 134 (1), 285-291 (2013)]. The modified CSI model considers the non-locally reactive effect of absorbers at oblique incidence, and the improvement is verified by a full, finite-element simulation of a small chamber. With the modified CSI model, the performance of both decorations with the optimized parameters in a large chamber is simulated. The simulation results are analyzed and checked against the tolerance of 1.5 dB deviation from the inverse square law, stipulated in the ISO standard 3745(2003). In terms of the total decoration depth and anechoic chamber performance, the UGFW structure is better than the classic wedge design.

  12. Reflection of cylindrical converging shock wave over a plane wedge

    NASA Astrophysics Data System (ADS)

    Zhang, Fu; Si, Ting; Zhai, Zhigang; Luo, Xisheng; Yang, Jiming; Lu, Xiyun

    2016-08-01

    The cylindrical converging shock reflection over a plane wedge is investigated experimentally and numerically in a specially designed shock tube which converts a planar shock into a cylindrical one. When the converging shock is moving along the wedge, both the shock strength and the incident angle are changing, which provides the possibility for the wave transition. The results show that both regular reflection (RR) and Mach reflection (MR) are found on the wedge with different initial incident angles. The wave transitions from direct Mach reflection (DiMR) to inverse Mach reflection (InMR) and further to transitioned regular reflection (TRR) are observed with appropriate initial incident angles. The instability development in the shear layer and strong vortices formation near the wall are evident, which are ascribed not only to the interaction of two shear layers but also to the shock impact and the shock converging effect. Because of the flow unsteadiness after the converging shock, the detachment criterion provides a good estimation for the RR → MR transition, but fails to predict the DiMR → InMR transition, and MR is found to persist slightly below the mechanical equilibrium condition. A hysteresis process is found in the MR → TRR transition and becomes more apparent as the increase of the initial incident angle due to the shock converging effect.

  13. Missing wedge computed tomography by iterative algorithm DIRECTT.

    PubMed

    Kupsch, Andreas; Lange, Axel; Hentschel, Manfred P; Lück, Sebastian; Schmidt, Volker; Grothausmann, Roman; Hilger, André; Manke, Ingo

    2015-01-01

    A strategy to mitigate typical reconstruction artefacts in missing wedge computed tomography is presented. These artefacts appear as elongations of reconstructed details along the mean direction (i.e. the symmetry centre of the projections). Although absent in standard computed tomography applications, they are most prominent in advanced electron tomography and also in special topics of X-ray and neutron tomography under restricted geometric boundary conditions. We investigate the performance of the DIRECTT (Direct Iterative Reconstruction of Computed Tomography Trajectories) algorithm to reduce the directional artefacts in standard procedures. In order to be sensitive to the anisotropic nature of missing wedge artefacts, we investigate isotropic substructures of metal foam as well as circular disc models. Comparison is drawn to filtered backprojection and algebraic techniques. Reference is made to reconstructions of complete data sets. For the purpose of assessing the reconstruction quality, Fourier transforms are employed to visualize the missing wedge directly. Deficient reconstructions of disc models are evaluated by a length-weighted kernel density estimation, which yields the probabilities of boundary orientations. The DIRECTT results are assessed at different signal-to-noise ratios by means of local and integral evaluation parameters. PMID:26367127

  14. Washing wedges: a capillary instability in a gradient of confinement

    NASA Astrophysics Data System (ADS)

    Keiser, Ludovic; Herbaut, Remy; Bico, Jose; Reyssat, Etienne

    2015-11-01

    When a drop of oil is introduced into a gradient of confinement (two glass plates forming a sharp wedge) capillary forces drive it toward the most confined regions, where the solid-fluid contact area is maximal. A surfactant solution subsequently introduced into the wedge undergoes the same movement until it reaches the oil previously added. If the aqueous phase wets the solid better than the oil, a complex exchange process between both phases occurs. The water-oil interface destabilizes, oil fingers grow in the water phase, pinch-off and lead to the formation of droplets that migrate away from the tip of the wedge. The whole oil phase is eventually extracted. A linear stability analysis of the interface is presented and captures the size of the oil droplets. The dynamics of the system is however not perfectly explained by a simple Poiseuille flow. Indeed, more refined models should account for the dissipation in meniscii and lubrication films. Finally, we suggest that our model experiment may constitute a useful tool to select optimal systems for oil recovery processes.

  15. Integrated waste management as a climate change stabilization wedge.

    PubMed

    Bahor, Brian; Van Brunt, Michael; Stovall, Jeff; Blue, Katherine

    2009-11-01

    Anthropogenic sources of greenhouse gas emissions are known to contribute to global increases in greenhouse gas concentrations and are widely believed to contribute to climate change. A reference carbon dioxide concentration of 383 ppm for 2007 is projected to increase to a nominal 500 ppm in less than 50 years according to business as usual models. This concentration change is equivalent to an increase of 7 billion tonnes of carbon per year (7 Gt C year(-1)). The concept of a stabilization wedge was introduced by Pacala and Socolow (Science, 305, 968-972, 2004) to break the 7 Gt C year(- 1) into more manageable 1 Gt C year(- 1) reductions that would be achievable with current technology. A total of fifteen possible 'wedges' were identified; however, an integrated municipal solid waste (MSW) management system based on the European Union's waste management hierarchy was not evaluated as a wedge. This analysis demonstrates that if the tonnage of MSW is allocated to recycling, waste to energy and landfilling in descending order in lieu of existing 'business-as-usual' practices with each option using modern technology and best practices, the system would reduce greenhouse gas emissions by more than 1 Gt C year( -1). This integrated waste management system reduces CO(2) by displacing fossil electrical generation and avoiding manufacturing energy consumption and methane emissions from landfills.

  16. Lessons Learned from Recently Opened High Schools: A Study of Process and Outcomes.

    ERIC Educational Resources Information Center

    Withycombe, Richard

    This case study of six newly-opened high schools explored: (1) What steps were taken to involve district staff members and community representatives in educational-specifications and design-development work? How effective did these steps prove to be? What impact did this involvement appear to have on the emergent and completed high school project?…

  17. A High-Leverage Language Teaching Practice: Leading an Open-Ended Group Discussion

    ERIC Educational Resources Information Center

    Kearney, Erin

    2015-01-01

    In response to calls for more practice-based teacher education, this study investigated the way in which two high-performing novice world language teachers, one in Spanish and one in Latin, implemented a high-leverage teaching practice, leading an open-ended group discussion. Observational data revealed a number of constituent micro-practices. The…

  18. Which Type of Inquiry Project Do High School Biology Students Prefer: Open or Guided?

    ERIC Educational Resources Information Center

    Sadeh, Irit; Zion, Michal

    2012-01-01

    In teaching inquiry to high school students, educators differ on which method of teaching inquiry is more effective: Guided or open inquiry? This paper examines the influence of these two different inquiry learning approaches on the attitudes of Israeli high school biology students toward their inquiry project. The results showed significant…

  19. Mantle wedge anisotropy in Southern Tyrrhenian Subduction Zone (Italy), from receiver function analysis

    NASA Astrophysics Data System (ADS)

    Piana Agostinetti, Nicola; Park, Jeffrey; Lucente, Francesco Pio

    2008-12-01

    We constrain mantle wedge seismic structure in the Southern Tyrrhenian Subduction Zone (Italy) using teleseismic receiver functions (RF) recorded at station CUC of the Mednet seismographic network. Station CUC lies above the northern portion of the Calabrian slab segment, which is recognized from deep seismicity and tomographic imaging as a narrow, laterally high-arched slab fragment, extending from the surface below Calabria down to the transition zone. To better define the descending slab interface and possible shear-coupled flow in the mantle wedge above the slab, we computed receiver functions from the P-coda of 147 teleseismic events to analyze the back-azimuth dependence of Ps converted phases from interfaces beneath CUC. We stack the RF data-set with back azimuth to compute its harmonic expansion, which relates to the effects of interface dip and anisotropy at layer boundaries. The seismic structure constrained through the RF analysis is characterized in its upper part by a sub-horizontal Moho at about 25 km depth, overlying a thin isotropic layer at top of mantle. For the deeper part, back-azimuth variation suggests two alternative models, each with an anisotropic layer between two dipping interfaces near 70- and 90-km depth, with fast- and slow-symmetry axes, respectively, above the Apennines slab. Although independent evidence suggests a north-south strike for the slab beneath CUC, the trend of the inferred anisotropy is 45° clockwise from north, inconsistent with a simple downdip shear-coupled flow model in the supra-slab mantle wedge. However complexities of flow and induced rock fabric in the Tyrrhenian back arc may arise due to several concurring factors such as the arcuate shape of the Apennines slab, its retreating kinematics, or slab edge effects.

  20. Video-assisted thoracoscopic wedge resections of pulmonary metastatic osteosarcoma: should it be performed?

    PubMed

    Yim, A P; Lin, J; Chan, A T; Li, C K; Ho, J K

    1995-10-01

    We studied the use of video-assisted thoracoscopic (VAT) surgery in the management of metastatic osteosarcoma. From September 1993 to March 1994, we performed a total of 11 VAT wedge resections of pulmonary metastatic osteosarcoma in seven patients (six males, one female, age 12 to 46 years). Three patients had bilateral procedures performed either under the same anaesthesia or in stages. One patient had two operations on the same side. The average number of nodules excised was three. Two patients subsequently required formal lobectomies when the metastatic tumours were either too big or too close to the hilum for safe wedge resections. There was one death on postoperative day 3 due to dysrhythmia. One patient died 5 months later from a progression of his underlying disease. Two patients remained disease free up to 8 and 12 months, respectively, from their first operations. The average postoperative chest drain duration was 1.4 +/- 0.7 days and hospital stay 2.3 +/- 1.1 days. The procedure was well tolerated and postoperative morbidity was minimal. We conclude that although VAT wedge resection of pulmonary metastatic osteosarcoma is feasible technically and is associated with a short hospital stay and minimal morbidity, this approach cannot be recommended when complete resection of all metastases is the goal as the technique relies heavily on computed tomographic scans to detect nodules. Recurrence of metastasis from 4 to 6 months in three of seven patients argues against VAT surgery being an adequate procedure. The high cost of the staplers, in addition, is a secondary consideration.

  1. Observations of the Columbia River salt wedge and estuarine turbidity maximum using AUVs

    NASA Astrophysics Data System (ADS)

    McNeil, C. L.; Shcherbina, A.; Litchendorf, T.; Sanford, T. B.; Martin, D.; Baptista, A. M.; Lopez, J.; Crump, B.

    2012-12-01

    We present detailed observations of the salt wedge and estuarine turbidity maxima (ETM) in the North Channel of the Columbia River estuary (OR, USA) under conditions of high river discharge during May 2012. Measurements were made using two REMUS-100 autonomous underwater vehicles (AUVs; Hydroid, Inc.) equipped with SBE-49 CTDs (Seabird-Electronics, Inc.) for water temperature and salinity, upward/downward looking ADCPs (Teledyne RDI, Inc.) for currents, and ECO Puck triplets (WET Labs, Inc.) for optical backscatter measurement of turbidity. The acoustic backscatter intensity from the ADCP was also used as a proxy measurement for suspended sediments and was found to correlate quite well with the optical backscatter measurements. Daily forecasts of tidal currents in the estuary were used to simulate the AUV path in advance of deployment to aid data collection. Repeat AUV sections were made along and across the channel during flood tide. The turbidity and height above riverbed of the bottom boundary layer was observed to increase toward the deeper waters at the center of the channel. An ETM-like feature was observed ahead of the advancing salt wedge front with locally higher turbidity levels, presumably the result of flocculation and resuspension. To visualize better the repeat section measurements we made data movies. Each frame of the movie is our best estimate of a synoptic snapshot of along-section tracer distribution at a given point in time. These snapshots were created by re-location of non-synoptic AUV measurements to account for the advection of water parcels. An example data movie showing the intrusion of the salt wedge during the flood tide will be presented.

  2. Subduction zone evolution and low viscosity wedges and channels

    NASA Astrophysics Data System (ADS)

    Manea, Vlad; Gurnis, Michael

    2007-12-01

    Dehydration of subducting lithosphere likely transports fluid into the mantle wedge where the viscosity is decreased. Such a decrease in viscosity could form a low viscosity wedge (LVW) or a low viscosity channel (LVC) on top of the subducting slab. Using numerical models, we investigate the influence of low viscosity wedges and channels on subduction zone structure. Slab dip changes substantially with the viscosity reduction within the LVWs and LVCs. For models with or without trench rollback, overthickening of slabs is greatly reduced by LVWs or LVCs. Two divergent evolutionary pathways have been found depending on the maximum depth extent of the LVW and wedge viscosity. Assuming a viscosity contrast of 0.1 with background asthenosphere, models with a LVW that extends down to 400 km depth show a steeply dipping slab, while models with an LVW that extends to much shallower depth, such as 200 km, can produce slabs that are flat lying beneath the overriding plate. There is a narrow range of mantle viscosities that produces flat slabs (5 to10 × 10 19 Pa s) and the slab flattening process is enhanced by trench rollback. Slab can be decoupled from the overriding plate with a LVC if the thickness is at least a few 10 s of km, the viscosity reduction is at least a factor of two and the depth extent of the LVC is several hundred km. These models have important implications for the geochemical and spatial evolution of volcanic arcs and the state of stress within the overriding plate. The models explain the poor correlation between traditional geodynamic controls, subducting plate age and convergence rates, on slab dip. We predict that when volcanic arcs change their distance from the trench, they could be preceded by changes in arc chemistry. We predict that there could be a larger volatile input into the wedge when arcs migrate toward the trench and visa-versa. The transition of a subduction zone into the flat-lying regime could be preceded by changes in the volatile

  3. Control of structural inheritance on thrust initiation and material transfer in accretionary wedges

    NASA Astrophysics Data System (ADS)

    Leever, Karen; Geersen, Jacob; Ritter, Malte; Lieser, Kathrin; Behrmann, Jan

    2016-04-01

    Faults in the incoming sediment layer are commonly observed in subduction zone settings and well developed in the incoming plate off Sumatra. To investigate how they affect the structural development of the accretionary wedge, we conducted a series of 2D analogue tectonic experiments in which a 2 cm thick quartz sand layer on top of a thin detachment layer of glass beads was pulled against a rigid backstop by a basal conveyor belt in a 20cm wide box with glass walls. A gap at the base of the back wall avoids entrainment of the glass beads. At regular spacing of either 2.3, 5.5 or 7.8 cm (fractions of the thrust sheet length in the reference model), conjugate pairs of weakness zones dipping 60deg were created by cutting the sand layer with a thin (1 mm) metal blade. Both the undisturbed sand and the pre-cuts have an angle of internal friction of ~29o, but their cohesion is different by 50 Pa (110 Pa for the undisturbed material, 60 Pa along the pre-cuts). Friction of the glass beads is ~24deg. The experiments are monitored with high resolution digital cameras; displacement fields derived from digital image correlation are used to constrain fault activity. In all experiments, a critically tapered wedge developed with a surface slope of 7.5deg. In the reference model (no weakness zones in the input section), the position of new thrust faults is controlled by the frontal slope break. The average length of the thrust sheets is 11 cm and the individual thrusts accommodate on average 8 cm displacement each. The presence of weakness zones causes thrust initiation at a position different from the reference case, and affects their dip. For a fault spacing of 7.8 cm (or 75% of the reference thrust sheet length), every single incoming weakness zone causes the formation of a new thrust, thus resulting in thrust sheets shorter than the equilibrium case. In addition, less displacement is accommodated on each thrust. As a consequence, the frontal taper is smaller than expected

  4. The immediate impact of opening an adult high dependency unit on intensive care unit occupancy.

    PubMed

    Fox, A J; Owen-Smith, O; Spiers, P

    1999-03-01

    We assessed the hourly occupancy of our intensive care and high dependency units over an 8-week period commencing on the day our high dependency unit opened. Using criteria established by the working group on 'Guidelines on Admission to and Discharge from Intensive Care and High Dependency Units' published by the National Health Service Executive, we defined each patient daily as intensive care or high dependency status. Compared with hourly occupancy figures obtained before the high dependency unit opened, occupancy of the intensive care unit by high dependency patients has been shown to decrease significantly from 21.6% to 11.2%. Use of intensive care beds became more appropriate, their occupancy increasing significantly from 63.7% to 73.4%. A significant decrease in readmissions occurred, supporting the hypothesis that having high dependency beds reduces the number of patients discharged prematurely to the wards.

  5. Linear array measurements of enhanced dynamic wedge and treatment planning system (TPS) calculation for 15 MV photon beam and comparison with electronic portal imaging device (EPID) measurements

    PubMed Central

    Petrovic, Borislava; Grzadziel, Aleksandra; Rutonjski, Laza; Slosarek, Krzysztof

    2010-01-01

    Introduction. Enhanced dynamic wedges (EDW) are known to increase drastically the radiation therapy treatment efficiency. This paper has the aim to compare linear array measurements of EDW with the calculations of treatment planning system (TPS) and the electronic portal imaging device (EPID) for 15 MV photon energy. Materials and methods. The range of different field sizes and wedge angles (for 15 MV photon beam) were measured by the linear chamber array CA 24 in Blue water phantom. The measurement conditions were applied to the calculations of the commercial treatment planning system XIO CMS v.4.2.0 using convolution algorithm. EPID measurements were done on EPID-focus distance of 100 cm, and beam parameters being the same as for CA24 measurements. Results Both depth doses and profiles were measured. EDW linear array measurements of profiles to XIO CMS TPS calculation differ around 0.5%. Profiles in non-wedged direction and open field profiles practically do not differ. Percentage depth doses (PDDs) for all EDW measurements show the difference of not more than 0.2%, while the open field PDD is almost the same as EDW PDD. Wedge factors for 60 deg wedge angle were also examined, and the difference is up to 4%. EPID to linear array differs up to 5%. Conclusions The implementation of EDW in radiation therapy treatments provides clinicians with an effective tool for the conformal radiotherapy treatment planning. If modelling of EDW beam in TPS is done correctly, a very good agreement between measurements and calculation is obtained, but EPID cannot be used for reference measurements. PMID:22933916

  6. Fluid and mass transfer into the cold mantle wedge of subduction zones: budgets and seismic constraints

    NASA Astrophysics Data System (ADS)

    Abers, G. A.; Hacker, B. R.; Van Keken, P. E.; Nakajima, J.; Kita, S.

    2015-12-01

    Dehydration of subducting plates should hydrate the shallow overlying mantle wedge where mantle is cold. In the shallow mantle wedge hydrous phases, notably serpentines, chlorite, brucite and talc should be stable to form a significant reservoir for H2O. Beneath this cold nose thermal models suggest only limited slab dehydration occurs at depths less than ca. 80 km except in warm subduction zones, but fluids may flow updip from deeper within the subducting plate to hydrate the shallow mantle. We estimate the total water storage capacity in cold noses, at temperatures where hydrous phases are stable, to be roughly 2-3% the mass of the global ocean. At modern subduction flux rates its full hydration could be achieved in 50-100 Ma if all subducting water devolatilized in the upper 100 km flows into the wedge; these estimates have at least a factor of two uncertainty. To investigate the extent to which wedge hydration actually occurs we compile and generate seismic images of forearc mantle regions. The compilation includes P- and S-velocity images with good sampling below the Moho and above the downgoing slab in forearcs, from active-source imaging, local earthquake tomography and receiver functions, while avoiding areas of complex tectonics. Well-resolved images exist for Cascadia, Alaska, the Andes, Central America, North Island New Zealand, and Japan. We compare the observed velocities to those predicted from thermal-petrologic models. Among these forearcs, Cascadia stands out as having upper-mantle seismic velocities lower than overriding crust, consistent with high (>50%) hydration. Most other forearcs show Vp close to 8.0 km/s and Vp/Vs of 1.73-1.80. We compare these observations to velocities predicted from thermal-mineralogical models. Velocities are slightly slower than expected for dry peridotite and allow 10-20% hydration, but also could also be explained as relict accreted rock, or delaminated, relaminated, or offscraped crustal material mixed with mantle

  7. Study of stress distribution of forming slandering of automobile semi-axes with multi-wedge cross wedge rolling by FEM simulation

    NASA Astrophysics Data System (ADS)

    Zhao, Jing; Shu, Xuedao; Hu, Zhenghuan

    2005-12-01

    Cross wedge rolling with multi-wedge (MCWR) is a new advanced technology of forming the slandering of automobile semi-axes. However, restriction relationship between main wedges and side wedges is complex, there is not almost theory forming automobile axes at inland or overseas. According to the characteristics of forming slandering of automobile semi-axes by MCWR, three-dimensional parameterized model of the MCWR and corresponding program of finite element simulation is worked out. Adopting FEM analysis technology, rules of stress distribution in work piece at main stages, such as knifing zone, stretching zone in main wedges was investigated. The results indicate that forming automobile semi-axes by MCWR is feasible. It provides reliable theory foundation for designing mould of rolling automobile axes by MCWR and choosing technology parameters.

  8. Rivers, re-entrants, and 3D variations in orogenic wedge development: a case study of the NW Indian Himalaya

    NASA Astrophysics Data System (ADS)

    Webb, A. G.; Yu, H.; Hendershott, Z.

    2010-12-01

    Orogenic wedges are standard elements of collisional plate tectonics, from accretionary prisms to retro-arc basins. Recent study of orogenic wedge development has focused on links between mechanisms of internal deformation and surface processes. Models of orogenic wedges are commonly presented in the cross-section plane, which is generally effective as wedges largely develop via plane strain. The 3rd dimension can be utilized to explore effects of differences in controlling parameters on wedge evolution. We are investigating a stretch of the western Himalayan orogenic wedge that has two prominent changes in along-strike morphology: (1) a tectonic window (the Kullu Window) that appears to be strongly influenced by erosion along the 3rd largest river in the Himalayan system, the Sutlej River and (2) the Kangra Re-entrant, the largest re-entrant along the Himalayan arc. In addition to the along-strike heterogeneity, a key advantage of the proposed study area is its rich stratigraphy, with the most known diversity in the Himalayan arc. The stratigraphic wealth, combined with the along-strike heterogeneity in exposure level, offers a high resolution view of regional structural geometry. Our preliminary reconstructions suggest that the Sutlej River erosion increases the exposure depth and shortening budget across a narrow segment of the orogen, strongly warping the Kullu Window. Previous models have suggested that the out-of-sequence Munsiari thrust is the main structure associated with Kullu window formation, while our work suggests that most of this uplift and warping is accomplished by antiformal stacking of basement thrust horses. Late Miocene ages (U-Pb ages of zircons and Th-Pb ages of monazites) from a leucogranite in the core of the Kullu Window along the Sutlej River further suggests that this segment of the orogen represents a middle ground between plane strain orogenic wedge development and a tectonic aneurysm model. We have constructed a palinspastic

  9. First 13 Years of HIGH-Tc:. Brief Review and Open Questions

    NASA Astrophysics Data System (ADS)

    Pavuna, Davor

    Exactly 13 years ago, in April 1986, appeared the famous paper1 by Bednorz and Müller, that announced a striking discovery of high-Tc superconductivity in cuprates. Some 40'000 papers later, we are still struggling to understand the high-Tc superconductivity. Here I summarize some of the most relevant recent results and open questions by discussing the observed phenomena in a rather complex electronic phase diagram of high-Tc oxides.

  10. Ammonia losses and nitrogen partitioning at a southern High Plains open lot dairy

    NASA Astrophysics Data System (ADS)

    Todd, Richard W.; Cole, N. Andy; Hagevoort, G. Robert; Casey, Kenneth D.; Auvermann, Brent W.

    2015-06-01

    Animal agriculture is a significant source of ammonia (NH3). Cattle excrete most ingested nitrogen (N); most urinary N is converted to NH3, volatilized and lost to the atmosphere. Open lot dairies on the southern High Plains are a growing industry and face environmental challenges as well as reporting requirements for NH3 emissions. We quantified NH3 emissions from the open lot and wastewater lagoons of a commercial New Mexico dairy during a nine-day summer campaign. The 3500-cow dairy consisted of open lot, manure-surfaced corrals (22.5 ha area). Lactating cows comprised 80% of the herd. A flush system using recycled wastewater intermittently removed manure from feeding alleys to three lagoons (1.8 ha area). Open path lasers measured atmospheric NH3 concentration, sonic anemometers characterized turbulence, and inverse dispersion analysis was used to quantify emissions. Ammonia fluxes (15-min) averaged 56 and 37 μg m-2 s-1 at the open lot and lagoons, respectively. Ammonia emission rate averaged 1061 kg d-1 at the open lot and 59 kg d-1 at the lagoons; 95% of NH3 was emitted from the open lot. The per capita emission rate of NH3 was 304 g cow-1 d-1 from the open lot (41% of N intake) and 17 g cow-1 d-1 from lagoons (2% of N intake). Daily N input at the dairy was 2139 kg d-1, with 43, 36, 19 and 2% of the N partitioned to NH3 emission, manure/lagoons, milk, and cows, respectively.

  11. Ammonia losses and nitrogen partitioning at a southern High Plains open lot dairy

    NASA Astrophysics Data System (ADS)

    Todd, Richard W.; Cole, N. Andy; Hagevoort, G. Robert; Casey, Kenneth D.; Auvermann, Brent W.

    2015-06-01

    Animal agriculture is a significant source of ammonia (NH3). Cattle excrete most ingested nitrogen (N); most urinary N is converted to NH3, volatilized and lost to the atmosphere. Open lot dairies on the southern High Plains are a growing industry and face environmental challenges as well as reporting requirements for NH3 emissions. We quantified NH3 emissions from the open lot and wastewater lagoons of a commercial New Mexico dairy during a nine-day summer campaign. The 3500-cow dairy consisted of open lot, manure-surfaced corrals (22.5 ha area). Lactating cows comprised 80% of the herd. A flush system using recycled wastewater intermittently removed manure from feeding alleys to three lagoons (1.8 ha area). Open path lasers measured atmospheric NH3 concentration, sonic anemometers characterized turbulence, and inverse dispersion analysis was used to quantify emissions. Ammonia fluxes (15-min) averaged 56 and 37 μg m-2 s-1 at the open lot and lagoons, respectively. Ammonia emission rate averaged 1061 kg d-1 at the open lot and 59 kg d-1 at the lagoons; 95% of NH3 was emitted from the open lot. The per capita emission rate of NH3 was 304 g cow-1 d-1 from the open lot (41% of N intake) and 17 g cow-1 d-1 from lagoons (2% of N intake). Daily N input at the dairy was 2139 kg d-1, with 43, 36, 19 and 2% of the N partitioned to NH3 emission, manure/lagoons, milk, and cows, respectively.

  12. Crystallization of soft matter under confinement at interfaces and in wedges

    NASA Astrophysics Data System (ADS)

    Archer, Andrew J.; Malijevský, Alexandr

    2016-06-01

    opening angle of the wedge is commensurate with the crystal lattice.

  13. Crystallization of soft matter under confinement at interfaces and in wedges.

    PubMed

    Archer, Andrew J; Malijevský, Alexandr

    2016-06-22

    The surface freezing and surface melting transitions that are exhibited by a model two-dimensional soft matter system are studied. The behaviour when confined within a wedge is also considered. The system consists of particles interacting via a soft purely repulsive pair potential. Density functional theory (DFT) is used to calculate density profiles and thermodynamic quantities. The external potential due to the confining walls is modelled via a hard wall with an additional repulsive Yukawa potential. The surface phase behaviour depends on the range and strength of this repulsion: when the repulsion is weak, the wall promotes freezing at the surface of the wall. The thickness of this frozen layer grows logarithmically as the bulk liquid-solid phase coexistence is approached. Our mean-field DFT predicts that this crystalline layer at the wall must be nucleated (i.e. there is a free energy barrier) and its formation is necessarily a first-order transition, referred to as 'prefreezing', by analogy with the prewetting transition. However, in contrast to the latter, prefreezing cannot terminate in a critical point, since the phase transition involves a change in symmetry. If the wall-fluid interaction is sufficiently long ranged and the repulsion is strong enough, surface melting can occur instead. Then the interface between the wall and the bulk crystalline solid is wetted by the liquid phase as the chemical potential is decreased towards the value at liquid-solid coexistence. It is observed that the finite thickness fluid film at the wall has a broken translational symmetry due to its proximity to the bulk crystal, and so the nucleation of the wetting film can be either first order or continuous. Our mean-field theory predicts that for certain wall potentials there is a premelting critical point analogous to the surface critical point for the prewetting transition. When the fluid is confined within a linear wedge, this can strongly promote freezing when the opening

  14. Crystallization of soft matter under confinement at interfaces and in wedges

    NASA Astrophysics Data System (ADS)

    Archer, Andrew J.; Malijevský, Alexandr

    2016-06-01

    opening angle of the wedge is commensurate with the crystal lattice.

  15. Analyzing Inquiry Questions of High-School Students in a Gas Chromatography Open-Ended Laboratory Experiment

    ERIC Educational Resources Information Center

    Blonder, Ron; Mamlock-Naaman, Rachel; Hofstein, Avi

    2008-01-01

    This paper describes the implementation of an open-ended inquiry experiment for high-school students, based on gas chromatography (GC). The research focuses on identifying the level of questions that students ask during the GC open inquiry laboratory, and it examines whether implementing the advanced inquiry laboratory opens up new directions for…

  16. Integrated Analysis Platform: An Open-Source Information System for High-Throughput Plant Phenotyping1[C][W][OPEN

    PubMed Central

    Klukas, Christian; Chen, Dijun; Pape, Jean-Michel

    2014-01-01

    High-throughput phenotyping is emerging as an important technology to dissect phenotypic components in plants. Efficient image processing and feature extraction are prerequisites to quantify plant growth and performance based on phenotypic traits. Issues include data management, image analysis, and result visualization of large-scale phenotypic data sets. Here, we present Integrated Analysis Platform (IAP), an open-source framework for high-throughput plant phenotyping. IAP provides user-friendly interfaces, and its core functions are highly adaptable. Our system supports image data transfer from different acquisition environments and large-scale image analysis for different plant species based on real-time imaging data obtained from different spectra. Due to the huge amount of data to manage, we utilized a common data structure for efficient storage and organization of data for both input data and result data. We implemented a block-based method for automated image processing to extract a representative list of plant phenotypic traits. We also provide tools for build-in data plotting and result export. For validation of IAP, we performed an example experiment that contains 33 maize (Zea mays ‘Fernandez’) plants, which were grown for 9 weeks in an automated greenhouse with nondestructive imaging. Subsequently, the image data were subjected to automated analysis with the maize pipeline implemented in our system. We found that the computed digital volume and number of leaves correlate with our manually measured data in high accuracy up to 0.98 and 0.95, respectively. In summary, IAP provides a multiple set of functionalities for import/export, management, and automated analysis of high-throughput plant phenotyping data, and its analysis results are highly reliable. PMID:24760818

  17. On the Origin of High-altitude Open Clusters in the Milky Way

    NASA Astrophysics Data System (ADS)

    Martinez-Medina, L. A.; Pichardo, B.; Moreno, E.; Peimbert, A.; Velazquez, H.

    2016-01-01

    We present a dynamical study of the effect of the bar and spiral arms on the simulated orbits of open clusters in the Galaxy. Specifically, this work is devoted to the puzzling presence of high-altitude open clusters in the Galaxy. For this purpose we employ a very detailed observationally motivated potential model for the Milky Way and a careful set of initial conditions representing the newly born open clusters in the thin disk. We find that the spiral arms are able to raise an important percentage of open clusters (about one-sixth of the total employed in our simulations, depending on the structural parameters of the arms) above the Galactic plane to heights beyond 200 pc, producing a bulge-shaped structure toward the center of the Galaxy. Contrary to what was expected, the spiral arms produce a much greater vertical effect on the clusters than the bar, both in quantity and height; this is due to the sharper concentration of the mass on the spiral arms, when compared to the bar. When a bar and spiral arms are included, spiral arms are still capable of raising an important percentage of the simulated open clusters through chaotic diffusion (as tested from classification analysis of the resultant high-z orbits), but the bar seems to restrain them, diminishing the elevation above the plane by a factor of about two.

  18. Structure of the Yeast DEAD Box Protein Mss116p Reveals Two Wedges that Crimp RNA

    SciTech Connect

    Del Campo, Mark; Lambowitz, Alan M.

    2010-01-12

    The yeast DEAD box protein Mss116p is a general RNA chaperone that functions in mitochondrial group I and II intron splicing, translational activation, and RNA end processing. Here we determined high-resolution X-ray crystal structures of Mss116p complexed with an RNA oligonucleotide and ATP analogs AMP-PNP, ADP-BeF{sub 3}, or ADP-AlF{sub 4}{sup -}. The structures show the entire helicase core acting together with a functionally important C-terminal extension. In all structures, the helicase core is in a closed conformation with a wedge {alpha} helix bending RNA 3' of the central bound nucleotides, as in previous DEAD box protein structures. Notably, Mss116p's C-terminal extension also bends RNA 5' of the central nucleotides, resulting in RNA crimping. Despite reported functional differences, we observe few structural changes in ternary complexes with different ATP analogs. The structures constrain models of DEAD box protein function and reveal a strand separation mechanism in which a protein uses two wedges to act as a molecular crimper.

  19. Polarization induced two dimensional confinement of carriers in wedge shaped polar semiconductors

    PubMed Central

    Deb, S.; Bhasker, H. P.; Thakur, Varun; Shivaprasad, S. M.; Dhar, S.

    2016-01-01

    A novel route to achieve two dimensional (2D) carrier confinement in a wedge shaped wall structure made of a polar semiconductor has been demonstrated theoretically. Tapering of the wall along the direction of the spontaneous polarization leads to the development of charges of equal polarity on the two inclined facades of the wall. Polarization induced negative (positive) charges on the facades can push the electrons (holes) inward for a n-type (p-type) material which results in the formation of a 2D electron (hole) gas at the central plane and ionized donors (acceptors) at the outer edges of the wall. The theory shows that this unique mode of 2D carrier confinement can indeed lead to a significant enhancement of carrier mobility. It has been found that the reduced dimensionality is not the only cause for the enhancement of mobility in this case. Ionized impurity scattering, which is one of the major contributer to carrier scattering, is significantly suppressed as the carriers are naturally separated from the ionized centers. A recent experimental finding of very high electron mobility in wedge shaped GaN nanowall networks has been analyzed in the light of this theoretical reckoning. PMID:27210269

  20. Polarization induced two dimensional confinement of carriers in wedge shaped polar semiconductors

    NASA Astrophysics Data System (ADS)

    Deb, S.; Bhasker, H. P.; Thakur, Varun; Shivaprasad, S. M.; Dhar, S.

    2016-05-01

    A novel route to achieve two dimensional (2D) carrier confinement in a wedge shaped wall structure made of a polar semiconductor has been demonstrated theoretically. Tapering of the wall along the direction of the spontaneous polarization leads to the development of charges of equal polarity on the two inclined facades of the wall. Polarization induced negative (positive) charges on the facades can push the electrons (holes) inward for a n-type (p-type) material which results in the formation of a 2D electron (hole) gas at the central plane and ionized donors (acceptors) at the outer edges of the wall. The theory shows that this unique mode of 2D carrier confinement can indeed lead to a significant enhancement of carrier mobility. It has been found that the reduced dimensionality is not the only cause for the enhancement of mobility in this case. Ionized impurity scattering, which is one of the major contributer to carrier scattering, is significantly suppressed as the carriers are naturally separated from the ionized centers. A recent experimental finding of very high electron mobility in wedge shaped GaN nanowall networks has been analyzed in the light of this theoretical reckoning.

  1. Simulation of arrested salt wedges with a multi-layer Shallow Water Lattice Boltzmann model

    NASA Astrophysics Data System (ADS)

    Prestininzi, P.; Montessori, A.; La Rocca, M.; Sciortino, G.

    2016-10-01

    The ability to accurately and efficiently model the intrusion of salt wedges into river beds is crucial to assay its interaction with human activities and the natural environment. We present a 2D multi-layer Shallow Water Lattice Boltzmann (SWLB) model able to predict the salt wedge intrusion in river estuaries. The formulation usually employed for the simulation of gravity currents is here equipped with proper boundary conditions to handle both the downstream seaside outlet and the upstream river inlet. Firstly, the model is validated against highly accurate semi-analytical solutions of the steady state 1D two-layer Shallow Water model. Secondly, the model is applied to a more complex, fully 3D geometry, to assess its capability to handle realistic cases. The simple formulation proposed for the shear interlayer stress is proven to be consistent with the general 3D viscous solution. In addition to the accuracy, the model inherits the efficiency of the Lattice Boltzmann approach to fluid dynamics problems.

  2. Ingestion of plastic debris by Laysan albatrosses and wedge-tailed shearwaters in the Hawaiian Islands

    USGS Publications Warehouse

    Fry, D.M.; Fefer, S.I.; Sileo, L.

    1987-01-01

    Surveys of Laysan Albatross and Wedge-tailed Shearwaters on Midway and Oahu Island, Hawaii, identified a high proportion of birds with plastic in the upper gastrointestinal tract, representing hazards to the health of adult birds and their chicks. Fifty Laysan Albatross chicks were examined for plastic items lodged within the upper digestive tract. Forty-five (90%) contained plastic, including 3 chicks having proventricular impactions or ulcerative lesions. Plastic items in 21 live albatross chicks weighed a mean of 35.7 g chicka??1 (range 1a??175 g). Four dead birds contained 14a??175 g (mean 76.7 g). Two of four adult albatross examined contained plastic in the gut. Laysan albatross chicks have the highest reported incidence and amount of ingested plastic of any seabird species. Twelve of 20 adult Wedge-tailed Shearwaters (60%) contained plastic particles 2a??4 mm in diameter. Impaction did not appear to be a significant hazard for adult shearwaters. Shearwater chicks were not examined. Chemical toxicity of plastic polymers, plasticizers and antioxidant additives is low, although many pigments are toxic and plastics may serve as vehicles for the adsorption of organochlorine pollutants from sea water, and the toxicity of plastics is unlikely to pose significant hazard compared to obstruction and impaction of the gut.

  3. Polarization induced two dimensional confinement of carriers in wedge shaped polar semiconductors.

    PubMed

    Deb, S; Bhasker, H P; Thakur, Varun; Shivaprasad, S M; Dhar, S

    2016-01-01

    A novel route to achieve two dimensional (2D) carrier confinement in a wedge shaped wall structure made of a polar semiconductor has been demonstrated theoretically. Tapering of the wall along the direction of the spontaneous polarization leads to the development of charges of equal polarity on the two inclined facades of the wall. Polarization induced negative (positive) charges on the facades can push the electrons (holes) inward for a n-type (p-type) material which results in the formation of a 2D electron (hole) gas at the central plane and ionized donors (acceptors) at the outer edges of the wall. The theory shows that this unique mode of 2D carrier confinement can indeed lead to a significant enhancement of carrier mobility. It has been found that the reduced dimensionality is not the only cause for the enhancement of mobility in this case. Ionized impurity scattering, which is one of the major contributer to carrier scattering, is significantly suppressed as the carriers are naturally separated from the ionized centers. A recent experimental finding of very high electron mobility in wedge shaped GaN nanowall networks has been analyzed in the light of this theoretical reckoning. PMID:27210269

  4. Magnetotail flux accumulation leading to auroral expansion and a substorm current wedge: case study

    NASA Astrophysics Data System (ADS)

    Chu, X.; McPherron, R. L.; Hsu, T. S.; Angelopoulos, V.; Weygand, J. M.; Strangeway, R. J.; Liu, J.

    2015-12-01

    Magnetotail burst busty flows, magnetic field dipolarization, and auroral poleward expansion are linked to the development of substorm current wedges (SCW). Although auroral brightening is often attributed to field-aligned currents (FACs) in the SCW produced by flow vorticity and pressure redistribution, in-situ observations addressing the mechanism that generates these currents have been scarce. Conjugate observations and modelling results utilizing magnetotail satellites, inversion technique for SCW, and auroral imagers were used to study the release, transport, and accumulation of magnetic flux by flows; dipolarization associated with substorm current wedge formation; and auroral poleward expansion during an isolated substorm on 13 February 2008. During early expansion phase, magnetic flux released by magnetic reconnection was transported by earthward flows. Some magnetic flux was accumulated in the near-Earth region, and the remainder was transported azimuthally by flow diversion. The accumulated flux created a high pressure region with vertically dipolarized and azimuthally bent magnetic field lines. The rotation of the magnetic field lines was consistent with the polarity of the SCW. In the near-Earth region, good agreement was found among the magnetic flux transported by the flows, the accumulated flux causing dipolarization inside the SCW, and the flux enclosed within the poleward-expanded auroral oval. This agreement demonstrates that magnetic flux from the flows accumulated and generated the SCW, the magnetic dipolarization, and the auroral poleward expansion. The quantity of accumulated flux appears to determine the amplitudes of these phenomena.

  5. Gap test modeling to predict wedge tests initiation of PBXN-103

    NASA Astrophysics Data System (ADS)

    Richmond, Clinton T.

    1998-07-01

    The experimental initiation of PBXN-103 by the standard wedge test has been modeled by using the HVRB initiation and growth model in the CTH code. The P-081 plane wave lens was used as initiator in these experiments. The wedge test was converted to a gap test by replacing the PBXN-103 wedge by a PBXN-103 cylinder. By modeling this gap test, shock initiation in PBXN-103 was calculated. The results of these calculations are in agreement with the data of the wedge test experiments. Comparison of the CTH code calculations with the wedge test data was accomplished by using an auxiliary program called the BCAT code. In particular, it computes the "pop plot" and compares it to the wedge test data. Shock initiation of PBX-9404 was also calculated by the HVRB model and the results compared to the initiation of PBX-9404 using the Lee-Tarver model. The two calculations from both of the models are very compatible.

  6. Modes of continental extension in a crustal wedge

    NASA Astrophysics Data System (ADS)

    Wu, Guangliang; Lavier, Luc L.; Choi, Eunseo

    2015-07-01

    We ran numerical experiments of the extension of a crustal wedge as an approximation to extension in an orogenic belt or a continental margin. We study the effects of the strength of the lower crust and of a weak mid-crustal shear zone on the resulting extension styles. A weak mid-crustal shear zone effectively decouples upper crustal extension from lower crustal flow. Without the mid-crustal shear zone, the degree of coupling between the upper and the lower crust increases and extension of the whole crust tends to focus on the thickest part of the wedge. We identify three distinct modes of extension determined by the strength of the lower crust, which are characterized by 1) localized, asymmetric crustal exhumation in a single massif when the lower crust is weak, 2) the formation of rolling-hinge normal faults and the exhumation of lower crust in multiple core complexes with an intermediate strength lower crust, and 3) distributed domino faulting over the weak mid-crustal shear zone when the lower crust is strong. A frictionally stronger mid-crustal shear zone does not change the overall model behaviors but extension occurred over multiple rolling-hinges. The 3 modes of extension share characteristics similar to geological models proposed to explain the formation of metamorphic core complexes: 1) the crustal flow model for the weak lower crust, 2) the rolling-hinge and crustal flow models when the lower crust is intermediate and 3) the flexural uplift model when the lower crust is strong. Finally we show that the intensity of decoupling between the far field extension and lower crustal flow driven by the regional pressure gradient in the wedge control the overall style of extension in the models.

  7. Evaluation of Wedged Arterial Injection as a New Technique for Delivery of Experimental Therapeutic Sustances into the Porcine Pancreas

    PubMed Central

    Latorre, Rafael; Hernández, Wendy; Sun, Fei; Sánchez-Margallo, Francisco; Gil, Francisco; López-Albors, Octavio; Vázquez, Jose M.; Usón, Jesús

    2011-01-01

    Objectives. To prospectively evaluate the technical feasibility and efficacy of wedged arterial injection (WAI) as a potential route for experimental selective therapy to the pancreas of healthy pigs. Materials and Methods. Selective angiographies were completed in ten pigs under general anaesthesia. By superselective angiography, the catheter was inserted and wedged into the major pancreatic artery, blocking the blood flow. In order to evaluate the efficacy of the WAI method, a DNA-specific fluorescent dye (Hoechst 33258) was used. Results. Histological study revealed a uniform distribution of the fluorescent dye within the nuclei of the endocrine and exocrine pancreatic cells. Pancreatic and liver enzymes as well as histopathology of the pancreas were normal. Conclusion. WAI is a highly effective minimally invasive methodology to target the porcine pancreas. The findings suggest that WAI may contribute to developing preclinical assays of pancreas gene or cell-transfer therapies in swine model. PMID:22007190

  8. "OpenLAB": A 2-Hour PCR-Based Practical for High School Students

    ERIC Educational Resources Information Center

    Bouakaze, Caroline; Eschbach, Judith; Fouquerel, Elise; Gasser, Isabelle; Kieffer, Emmanuelle; Krieger, Sophie; Milosevic, Sara; Saandi, Thoueiba; Florentz, Catherine; Marechal-Drouard, Laurence; Labouesse, Michel

    2010-01-01

    The Strasbourg University PhD school in Life and Health Sciences launched an initiative called "OpenLAB." This project was developed in an effort to help high school teenagers understand theoretical and abstract concepts in genetics. A second objective of this program is to help students in defining their future orientation and to attract them to…

  9. Opening the Creative Mind of High Need for Cognitive Closure Individuals through Activation of Uncreative Ideas

    ERIC Educational Resources Information Center

    Ong, Lay See; Leung, Angela K.-Y.

    2013-01-01

    Drawing on the integrative system theory of creativity combining the person, process, and press perspectives, this research offers the first evidence of how high-need-for-cognitive-closure (NFC) individuals' creative mind can be opened up, by making them become more cognizant of uncreative ideas as consensually invalid solutions to creative…

  10. My Former Students' Reflections on Having an Openly Gay Teacher in High School

    ERIC Educational Resources Information Center

    Macgillivray, Ian

    2008-01-01

    This study examines how high school students were affected by having an openly gay teacher and compares its results to a previous study (Rofes, 2000). The author's lesbian, gay, or bisexual students experienced a sense of relief that they could finally feel comfortable about themselves, as well as feeling happy that others in the school were…

  11. Inverted-wedge silica resonators for controlled and stable coupling.

    PubMed

    Bo, Fang; Huang, Steven He; Özdemir, Sahin Kaya; Zhang, Guoquan; Xu, Jingjun; Yang, Lan

    2014-04-01

    Silica microresonators with an inverted-wedge shape were fabricated using conventional semiconductor fabrication methods. The measured quality factors of the resonators were greater than 10(6) in 1550 nm band. Controllable coupling from undercoupling to the overcoupling regime through the critical coupling point was demonstrated by horizontally moving a fiber taper while in touch with the top surface of the resonator. The thin outer ring of the resonator provided a support for the fiber taper leading to robust stable coupling. PMID:24686619

  12. The Newton two-knife experiment: Intricacies of wedge diffraction

    NASA Astrophysics Data System (ADS)

    Silverman, M. P.; Strange, Wayne

    1996-06-01

    About a century before Young's celebrated two-slit experiment, Isaac Newton quantitatively investigated the diffraction of light from a wedge aperture, but failed to understand the implications of his findings. We have reexamined this unusual system theoretically within the framework of the Fresnel-Kirchhoff scalar diffraction theory, and experimentally using a laser light source with pinhole spatial filter and CCD camera. Both the far-field shadow region and near-field directly illuminated region reveal aesthetically striking images that are deducible from the mathematical analysis, but whose interpretation is subtle and best elucidated by an alternative and less widely known perspective of diffraction.

  13. Hexahedron, wedge, tetrahedron, and pyramid diffusion operator discretization

    SciTech Connect

    Roberts, R.M.

    1996-08-06

    The diffusion equation, {phi}({rvec x}), is solved by finding the extrema of the functional, {Gamma}[{phi}] = {integral}({1/2}D{rvec {nabla}}{phi}{center_dot}{rvec {nabla}}{phi} + {1/2}{sigma}{sub a}{phi}{sup 2} - {ital Q}{phi}){ital d}{sup 3}{ital x}. A matrix is derived that is investigated for hexahedron, wedge, tetrahedron, and pyramid cells. The first term of the diffusion integration was concentrated and the others dropped; these dropped terms are also considered. Results are presented for hexahedral meshes and three weighting methods.

  14. On the Use of a Driven Wedge Test to Acquire Dynamic Fracture Energies of Bonded Beam Specimens

    SciTech Connect

    Dillard, David A.; Pohilt, David; Jacob, George Chennakattu; Starbuck, Michael; Rakesh, Kapania

    2011-01-01

    A driven wedge test is used to characterize the mode I fracture resistance of adhesively bonded composite beam specimens over a range of crosshead rates up to 1 m/s. The shorter moment arms (between wedge contact and crack tip) significantly reduce inertial effects and stored energy in the debonded adherends, when compared with conventional means of testing double cantilever beam (DCB) specimens. This permitted collecting an order of magnitude more crack initiation events per specimen than could be obtained with end-loaded DCB specimens bonded with an epoxy exhibiting significant stick-slip behavior. The localized contact of the wedge with the adherends limits the amount of both elastic and kinetic energy, significantly reduces crack advance during slip events, and facilitates higher resolution imaging of the fracture zone with high speed imaging. The method appears to work well under both quasi-static and high rate loading, consistently providing substantially more discrete fracture events for specimens exhibiting pronounced stick-slip failures. Deflections associated with beam transverse shear and root rotation for the shorter beams were not negligible, so simple beam theory was inadequate for obtaining qualitative fracture energies. Finite element analysis of the specimens, however, showed that fracture energies were in good agreement with values obtained from traditional DCB tests. The method holds promise for use in dynamic testing and for characterizing bonded or laminated materials exhibiting significant stick slip behavior, reducing the number of specimens required to characterize a sufficient number of fracture events.

  15. A microfabricated wedge-shaped adhesive array displaying gecko-like dynamic adhesion, directionality and long lifetime.

    PubMed

    Parness, Aaron; Soto, Daniel; Esparza, Noé; Gravish, Nick; Wilkinson, Matt; Autumn, Kellar; Cutkosky, Mark

    2009-12-01

    Gecko adhesion has become a paradigmatic example of bio-inspired engineering, yet among the many gecko-like synthetic adhesives (GSAs), truly gecko-like performance remains elusive. Many GSAs have previously demonstrated one or two features of the gecko adhesive. We present a new wedge-shaped GSA that exhibits several gecko-like properties simultaneously: directional features; zero force at detachment; high ratio of detachment force to preload force; non-adhesive default state; and the ability to maintain performance while sliding, even after thousands of cycles. Individual wedges independently detach and reattach during sliding, resulting in high levels of shear and normal adhesion during drag. This behaviour provides a non-catastrophic failure mechanism that is desirable for applications such as climbing robots where sudden contact failure would result in serious falls. The effects of scaling patch sizes up to tens of square centimetres are also presented and discussed. Patches of 1 cm(2) had an adhesive pressure of 5.1 kPa while simultaneously supporting 17.0 kPa of shear. After 30 000 attachment/detachment cycles, a patch retained 67 per cent of its initial adhesion and 76 per cent of its initial shear without cleaning. Square-based wedges of 20 mum and 50 mum are manufactured in a moulding process where moulds are fabricated using a dual-side, dual-angle lithography process on quartz wafers with SU-8 photoresist as the mould material and polydimethylsiloxane as the cast material.

  16. Surface acoustic admittance of highly porous open-cell, elastic foams

    NASA Technical Reports Server (NTRS)

    Lambert, R. F.

    1983-01-01

    This work presents a comprehensive study of the surface acoustic admittance properties of graded sizes of open-cell foams that are highly porous and elastic. The intrinsic admittance as well as properties of samples of finite depth were predicted and then measured for sound at normal incidence over a frequency range extending from about 35-3500 Hz. The agreement between theory and experiment for a range of mean pore size and volume porosity is excellent. The implications of fibrous structure on the admittance of open-cell foams is quite evident from the results.

  17. SPIM-fluid: open source light-sheet based platform for high-throughput imaging.

    PubMed

    Gualda, Emilio J; Pereira, Hugo; Vale, Tiago; Estrada, Marta Falcão; Brito, Catarina; Moreno, Nuno

    2015-11-01

    Light sheet fluorescence microscopy has recently emerged as the technique of choice for obtaining high quality 3D images of whole organisms/embryos with low photodamage and fast acquisition rates. Here we present an open source unified implementation based on Arduino and Micromanager, which is capable of operating Light Sheet Microscopes for automatized 3D high-throughput imaging on three-dimensional cell cultures and model organisms like zebrafish, oriented to massive drug screening. PMID:26601007

  18. SPIM-fluid: open source light-sheet based platform for high-throughput imaging

    PubMed Central

    Gualda, Emilio J.; Pereira, Hugo; Vale, Tiago; Estrada, Marta Falcão; Brito, Catarina; Moreno, Nuno

    2015-01-01

    Light sheet fluorescence microscopy has recently emerged as the technique of choice for obtaining high quality 3D images of whole organisms/embryos with low photodamage and fast acquisition rates. Here we present an open source unified implementation based on Arduino and Micromanager, which is capable of operating Light Sheet Microscopes for automatized 3D high-throughput imaging on three-dimensional cell cultures and model organisms like zebrafish, oriented to massive drug screening. PMID:26601007

  19. Perspectives on open access high resolution digital elevation models to produce global flood hazard layers

    NASA Astrophysics Data System (ADS)

    Sampson, Christopher; Smith, Andrew; Bates, Paul; Neal, Jeffrey; Trigg, Mark

    2015-12-01

    Global flood hazard models have recently become a reality thanks to the release of open access global digital elevation models, the development of simplified and highly efficient flow algorithms, and the steady increase in computational power. In this commentary we argue that although the availability of open access global terrain data has been critical in enabling the development of such models, the relatively poor resolution and precision of these data now limit significantly our ability to estimate flood inundation and risk for the majority of the planet's surface. The difficulty of deriving an accurate 'bare-earth' terrain model due to the interaction of vegetation and urban structures with the satellite-based remote sensors means that global terrain data are often poorest in the areas where people, property (and thus vulnerability) are most concentrated. Furthermore, the current generation of open access global terrain models are over a decade old and many large floodplains, particularly those in developing countries, have undergone significant change in this time. There is therefore a pressing need for a new generation of high resolution and high vertical precision open access global digital elevation models to allow significantly improved global flood hazard models to be developed.

  20. Preliminary engineering study: Quick opening valve MSFC high Reynolds number wind tunnel

    NASA Technical Reports Server (NTRS)

    1983-01-01

    FluiDyne Engineering Corporation has conducted a preliminary engineering study of a quick-opening valve for the MSFC High Reynolds Number Wind Tunnel under NASA Contract NAS8-35056. The subject valve is intended to replace the Mylar diaphragm system as the flow initiation device for the tunnel. Only valves capable of opening within 0.05 sec. and providing a minimum of 11.4 square feet of flow area were considered. Also, the study focused on valves which combined the quick-opening and tight shutoff features in a single unit. A ring sleeve valve concept was chosen for refinement and pricing. Sealing for tight shutoff, ring sleeve closure release and sleeve actuation were considered. The resulting cost estimate includes the valve and requisite modifications to the facility to accommodate the valve as well as the associated design and development work.

  1. Equivalent Thermal Conductivity of Open-Cell Ceramic Foams at High Temperatures

    NASA Astrophysics Data System (ADS)

    Li, J. E.; Wang, B.

    2014-01-01

    At high temperature, heat transfer in open-cell foams occurs by thermal radiation through the whole medium as well as by conduction through the solid matrix and air filling the pores. This paper applies the body-centered cubic cell model to predict radiative properties and the thermal conductivity of the open-cell foams. The model is validated by comparing the results with previous published works. Effects of structural characteristic parameters (cell diameter and porosity) and optical properties of the solid matrix (reflectivity and specularity parameter) on extinction coefficients and the radiative conductivity are discussed. The influence of temperature on the thermal conductivities including the effective, radiative, and the equivalent conductivity of open-cell ceramic foams are analyzed.

  2. Mass stranding of wedge-tailed shearwater chicks in Hawaii

    USGS Publications Warehouse

    Work, T.M.; Rameyer, R.A.

    1999-01-01

    Unusual numbers of wedge-tailed shearwater (Puffinus pacificus) chicks stranded on Oahu (Hawaii, USA) in 1994. Compared to healthy wedge-tailed shearwater (WTSW) chicks, stranded chicks were underweight, dehydrated, leukopenic, lymphopenic, eosinopenic, and heterophilic; some birds were toxemic and septic. Stranded chicks also were hypoglycemic and had elevated aspartate amino transferase levels. Most chicks apparently died from emaciation, dehydration, or bacteremia. Because many birds with bacteremia also had severe necrosis of the gastrointestinal (GI) mucosa associated with bacteria, we suspect the GI tract to be the source of disseminated bacterial infection. The identity of the bacteria was not confirmed. The daily number of chicks stranded was significantly related to average wind speeds, and the mortality coincided with the fledging period for WTSW. Strong southeasterly winds were a distinguishing meteorologic factor in 1994 and contributed to the distribution of stranded chicks on Oahu. More objective data on WTSW demographics would enhance future efforts to determine predisposing causes of WTSW wrecks and their effects on seabird colonies.

  3. Supercritical aqueous fluids in subduction zones carrying carbon and sulfur: oxidants for the mantle wedge?

    NASA Astrophysics Data System (ADS)

    Sverjensky, Dimitri; Manning, Craig

    2014-05-01

    magnesite, the C/S ratio can vary from 0.2 to 3.5 when temperature varies from 650 to 750 °C at 4 GPa. Fe concentrations remain negligible. These results strongly suggest that aqueous subarc eclogitic fluids that evolve to QFM +3 to +4, perhaps by reaction with metamorphosed Fe-oxide-bearing sediments, could transport significant amounts of C and/or S into the mantle wedge environment depending on the temperature. Hotter subduction should favor high C/S fluids, whereas colder subduction should favor low C/S fluids. Aqueous Fe transport is unlikely to be playing a significant role in oxidizing the mantle wedge. Sverjensky, D. A., Harrison, B., and Azzolini, D., 2014. Water in the deep Earth: the dielectric constant and the solubilities of quartz and corundum to 60 kb and 1,200°C. Geochim. et Cosmochim. Acta (in press).

  4. Growth of the deposit wedge in the mountain reservoir

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Song, G.

    2011-12-01

    The sedimentary problem of mountain reservoirs in Taiwan is getting serious year by year.Due to eroded sediments enter downstream reservoirs,the loss of sediment transport capacity may cause deposition of sediment in reservoirs.This phenomenon make problems to small mountain reservoirs.To realize the interaction between deposit wedges and mountain reservoirs,we selected Wushe reservoir which is situated in central Taiwan for a case study. Wushe reservoir is long and narrow.In recent years,most sediment is introduced during rain events that now accompany climate change are very important in sediment supply.In this thesis,we collected data of underwater landform and sub-bottom bedding information by using high resolution Multibeam Survey System(MBS) and seismic-reflection system.Up to now,we already had the bathymetric data for more than ten years,moreover,in 2010,we used 3.5kHz sub-bottom seismic profiler to analysis the sedimentary bedding situation in this area.These methods provide us accurate reservoir topography,sediment accumulation and the major ways of sediment transportation.The study purposes are as follows: First,according to the available underwater data for last ten years,we recognize the geomorphological characters of sedimentation as well as complete the mappings.Comparing to bathymetric images each year,we evaluate the carried ways of sediment.The flow water which enters this area transports along the thalweg,which in eastern reservoir.The range of water level variation cause alteration of sedimentary morphology,it also affects the scope of alluvial fan.The alluvial fan is located in the middle of the reservoir,the edge of it had moved forward 500 meters for last ten years.The annual mean of forward velocity was 50 meters,the elevation of fan edge also accelerated 10 meters per year.In a word,the large volume of the sedimentary delta is in Wushe reservoir now. Second,trying to clarify the composition of sedimentation and explain the sub

  5. Arc-parallel extension and fluid flow in an ancient accretionary wedge: The San Juan Islands, Washington

    USGS Publications Warehouse

    Schermer, E.R.; Gillaspy, J.R.; Lamb, R.

    2007-01-01

    Structural analysis of the Lopez Structural Complex, a major Late Cretaceous terrane-bounding fault zone in the San Juan thrust system, reveals a sequence of events that provides insight into accretionary wedge mechanics and regional tectonics. After formation of regional ductile flattening and shear-related fabrics, the area was crosscut by brittle structures including: (1) southwest-vergent thrusts, (2) extension veins and normal faults related to northwest-southeast extension, and (3) conjugate strike-slip structures that record northwest-southeast extension and northeast-southwest shortening. Aragonite-bearing veins are associated with thrust and normal faults, but only rarely with strike-slip faults. High-pressure, low-temperature (HP-LT) minerals constrain the conditions for brittle deformation to ???20 km and <250 ??C. The presence of similar structures elsewhere indicates that the brittle structural sequence is typical of the San Juan nappes. Sustained HP-LT conditions are possible only if structures formed in an accretionary prism during active subduction, which suggests that these brittle structures record internal wedge deformation at depth and early during uplift of the San Juan nappes. The structures are consistent with orogen-normal shortening and vertical thickening followed by vertical thinning and along-strike extension. The kinematic evolution may be related initially to changes in wedge strength, followed by response to overthickening of the wedge in an unbuttressed, obliquely convergent setting. The change in vein mineralogy indicates that exhumation occurred prior to the strike-slip event. The pressure and temperature conditions and spatial and temporal extent of small faults associated with fluid flow suggest a link between these structures and the silent earthquake process. ?? 2007 Geological Society of America.

  6. Mosaic of Wedge, Shark, Half-Dome, Moe and Flat Top

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The front cameras aboard the rover Sojourner imaged several prominent rocks on Sol 44. The highly-textured rock at left is Wedge, and in the background from left to right are Shark, Half-Dome, and Moe. The rectangular rock at right is Flat Top, which earlier close-up images revealed to be made up of elongated pits, possibly made by vesicles from volcanic outgassing or etches caused by weathering.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

  7. Laparoscopic versus open radical prostatectomy in high prostate volume cases: impact on oncological and functional results

    PubMed Central

    Alessandro, Sciarra; Alessandro, Gentilucci; Susanna, Cattarino; Michele, Innocenzi; Francesca, Di Quilio; Andrea, Fasulo; heland, Magnus Von; Vincenzo, Gentile; Stefano, Salciccia

    2016-01-01

    ABSTRACT Background and objective: To prospectively compare the laparoscopic versus open approach to RP in cases with high prostate volume and to evaluate a possible different impact of prostate volume. Materials and Methods: From March 2007 to March 2013 a total of 120 cases with clinically localized prostate cancer (PC) and a prostate volume>70cc identified for radical prostatectomy (RP), were prospectively analyzed in our institute. Patients were offered as surgical technique either an open retropubic or an intraperitoneal laparoscopic (LP) approach. In our population, 54 cases were submitted to LP and 66 to open RP. We analyzed the association of the surgical technique with perioperative, oncological and postoperative functional parameters. Results: In those high prostate volume cases, the surgical technique (laparoscopic versus open) does not represent a significant independent factor able to influence positive surgical margins rates and characteristics (p=0.4974). No significant differences (p>0.05) in the overall rates of positive margins was found, and also no differences following stratification according to the pathological stage and nerve sparing (NS) procedure. The surgical technique was able to significantly and independently influence the hospital stay, time of operation and blood loss (p<0.001). On the contrary, in our population, the surgical technique was not a significant factor influencing all pathological and 1-year oncological or functional outcomes (p>0.05). Conclusions: In our prospective non randomized analysis on high prostate volumes, the laparoscopic approach to RP is able to guarantee the same oncological and functional results of an open approach, maintaining the advantages in terms of perioperative outcomes. PMID:27256175

  8. Wedge and spring assembly for securing coils in electromagnets and dynamoelectric machines

    SciTech Connect

    Lindner, M.; Cottingham, J.G.

    1994-12-31

    A wedge and spring assembly for use in electromagnets or dynamoelectric machines having a housing with an axis therethrough and a plurality of coils supported on salient poles that extend radially inward from the housing toward the housing axis to define a plurality of interpole spaces, respectively between the housing and adjacent coils, the interpole spaces each extending in a direction generally parallel to the housing axis. The wedge and spring assembly includes a nonmagnetic retainer spring and a nonmagnetic wedge. The retainer spring is formed to fit into one of the interpole spaces, and has juxtaposed ends defining between them a slit extending in a direction generally parallel to the housing axis. The wedge for insertion into the slit provides an outwardly directed force on respective portions of the juxtaposed ends defining the slit to expand the slit so that respective portions of the retainer spring engage areas of the coils adjacent thereto, thereby resiliently holding the coils against their respective salient poles. Preferably, the spring retainer and wedge are self-locking wherein wedge is fabricated from a material softer than a material the retainer spring is fabricated from, so that the wedge is securely retained in the slit. The retainer spring is generally triangular shaped to fit within the interpole space and fabricated from berryllium-copper alloy, and the wedge is generally T-shaped and fabricated from aluminum. Alternatively, a wedge and spring assembly includes a wedge having divergent sloped surfaces in which each surface and the respective juxtaposed ends of the retainer spring are angled relative to one another so that the wedge is securely retained in the slit by friction existing between its sloped surfaces and the juxtaposed ends of the retaining spring.

  9. Properties of HIGH-Tc Cuprates: Some Recent Results and Open Questions

    NASA Astrophysics Data System (ADS)

    Vobornik, Ivana; Pavuna, Davor

    Thirteen years ago, late in 1986, several groups confirmed striking claims of the famous paper by Bednorz and M[Z Phys. B 64 (1986) 189] that announced the discovery of high-Tc superconductivity in cuprates. Some 60,000 papers later, we are still struggling to understand the high-Tc oxide superconductivity. Here we present some of the most relevant recent experiments and discuss some open questions across rather complex electronic phase diagram; we also note an important role of un-intentional and intentional disorder in these layered, high-Tc oxides.

  10. The role of aerothermochemistry in double cone and double wedge flows

    NASA Astrophysics Data System (ADS)

    Swantek, Andrew

    In this work, hypervelocity flows over double cone and double wedge geometries are studied. The flow configurations established over the double cone/double wedge models are extremely sensitive to thermochemistry, and thus serve as ideal benchmarks for validating chemical models. The goals of this research are: i) to investigate the coupling between the fluid mechanics and thermochemistry in these flow fields by varying freestream flow composition and enthalpy, ii) to implement a diagnostic suite for time-resolved surface and freestream measurements, iii) to investigate the nature of flow field unsteadiness across various test conditions, and lastly iv) to extend the experimental database for shock wave boundary/layer interactions. An expansion tube is used to generate flows with enthalpies ranging from 2.2-8.0 MJ/kg (2-4 km/s) and Mach numbers from 4-7. The expansion tube is a novel impulse facility for accelerating a test gas to these velocities, while maintaining a minimally dissociated freestream. Additionally, the facility allows variation of the freestream composition (between nitrogen and air), while maintaining freestream test parameters (Mach number, density, enthalpy) to within 0.5%. Two models are used: a 25-55 degree double cone model and a 30-55 degree double wedge. There are four diagnostic components to this research which aim to enable a better understanding of these canonical flow fields. Single frame, high resolution schlieren photography is used to visualize various flow features including: the separation zone formed in the corner, the triple point interaction, and a supersonic shear layer. From these images, a separation zone length scaling parameter is determined. This parameter, derived for wedge geometries, is successfully applied to conical geometries by using a judicious choice of flow properties for scaling. In the wedge image series, nitrogen test conditions exhibit a distinct increase in bow shock standoff distance. Additionally, aft

  11. Perceptions of low agency and high sexual openness mediate the relationship between sexualization and sexual aggression.

    PubMed

    Blake, Khandis R; Bastian, Brock; Denson, Thomas F

    2016-09-01

    Researchers have become increasingly interested in the saturation of popular Western culture by female hypersexualization. We provide data showing that men have more sexually aggressive intentions toward women who self-sexualize, and that self-sexualized women are vulnerable to sexual aggression if two qualifying conditions are met. Specifically, if perceivers view self-sexualized women as sexually open and lacking agency (i.e., the ability to influence one's environment), they harbor more sexually aggressive intentions and view women as easier to sexually victimize. In Experiment 1, male participants viewed a photograph of a woman whose self-sexualization was manipulated through revealing versus non-revealing clothing. In subsequent experiments, men and women (Experiment 2) and men only (Experiment 3) viewed a photograph of a woman dressed in non-revealing clothing but depicted as open or closed to sexual activity. Participants rated their perceptions of the woman's agency, then judged how vulnerable she was to sexual aggression (Experiments 1 and 2) or completed a sexually aggressive intentions measure (Experiment 3). Results indicated that both men and women perceived self-sexualized women as more vulnerable to sexual aggression because they assumed those women were highly sexually open and lacked agency. Perceptions of low agency also mediated the relationship between women's perceived sexual openness and men's intentions to sexually aggress. These effects persisted even when we described the self-sexualized woman as possessing highly agentic personality traits and controlled for individual differences related to sexual offending. The current work suggests that perceived agency and sexual openness may inform perpetrator decision-making and that cultural hypersexualization may facilitate sexual aggression. Aggr. Behav. 42:483-497, 2016. © 2016 Wiley Periodicals, Inc. PMID:26848102

  12. Propagation of sound in highly porous open-cell elastic foams

    NASA Technical Reports Server (NTRS)

    Lambert, R. F.

    1983-01-01

    This work presents both theoretical predictions and experimental measurements of attenuation and progressive phase constants of sound in open-cell, highly porous, elastic polyurethane foams. The foams are available commercially in graded pore sizes for which information about the static flow resistance, thermal time constant, volume porosity, dynamic structure factor, and speed of sound is known. The analysis is specialized to highly porous foams which can be efficient sound absorbers at audio frequencies. Negligible effect of internal wave coupling on attenuation and phase shift for the frequency range 16-6000 Hz was predicted and no experimentally significant effects were observed in the bulk samples studied. The agreement between predictions and measurements in bulk materials is excellent. The analysis is applicable to both the regular and compressed elastic open-cell foams.

  13. Google Classroom and Open Clusters: An Authentic Science Research Project for High School Students

    NASA Astrophysics Data System (ADS)

    Johnson, Chelen H.; Linahan, Marcella; Cuba, Allison Frances; Dickmann, Samantha Rose; Hogan, Eleanor B.; Karos, Demetra N.; Kozikowski, Kendall G.; Kozikowski, Lauren Paige; Nelson, Samantha Brooks; O'Hara, Kevin Thomas; Ropinski, Brandi Lucia; Scarpa, Gabriella; Garmany, Catharine D.

    2016-01-01

    STEM education is about offering unique opportunities to our students. For the past three years, students from two high schools (Breck School in Minneapolis, MN, and Carmel Catholic High School in Mundelein, IL) have collaborated on authentic astronomy research projects. This past year they surveyed archival data of open clusters to determine if a clear turnoff point could be unequivocally determined. Age and distance to each open cluster were calculated. Additionally, students requested time on several telescopes to obtain original data to compare to the archival data. Students from each school worked in collaborative teams, sharing and verifying results through regular online hangouts and chats. Work papers were stored in a shared drive and on a student-designed Google site to facilitate dissemination of documents between the two schools.

  14. Changing conditions of mantle wedge melting across arc as illustrated by changing iron isotopes compositions

    NASA Astrophysics Data System (ADS)

    Foden, J. D.; Halverson, G. P.; Sossi, P.; Elburg, M. A.

    2009-12-01

    Active volcanoes in the eastern Sunda Arc , Indonesia are distributed across a wide range of position above the active Benioff Zone. These include the near fore-arc tholeiite suite from Ija volcano on Flores Island which is about 100 Km above the slab. Then at successively greater depths are the archetypal calcalkaline suites of Rinjani and Batur volcanoes on Lombok and Bali and then the rear arc alkalic suites from Tambora, Sangeang Api and Batu Tara. The latter approaching 200km above the slab. The fore-arc volcano Ija is clearly influenced by hydrous fluid flux from the slab, having high Ba/Th and U/Nb ratios. The strongly undersaturated alkalic suites from Tambora and Batu Tara are highly enriched in LIL incompatible elements, but do not have sufficiently anomalously high 87Sr/86Sr or Pb isotopic ratios or low 143Nd/144Nd ratios to explain this anomaly as entirely due to significantly larger components of subducted sediment. This implies that these rear arc volcanoes are the product of smaller percentage melting of the supra-slab mantle wedge. This is also consistent with the determined lower water content of Tambora basalts compared with Ija fore-arc basalts. δ56Fe values were determined and show a systematic increase across the arc that is equivalent to that determined by other workers between some global MORB and OIB suites the bulk earth. This is like across arc variation described elsewhere (New Britain; Dauphas et al., 2009). It appears that this stable isotope fractionation results from the changed mode of melt percolation and extraction from the deeper, rear arc mantle wedge domains compared to the shallow fore-arc.

  15. Revisit the classical Newmark displacement method for earthquake-induced wedge slide

    NASA Astrophysics Data System (ADS)

    Yang, Che-Ming; Cheng, Hui-Yun; Wu, Wen-Jie; Hsu, Chang-Hsuan; Dong, Jia-Jyun; Lee, Chyi-Tyi

    2016-04-01

    Newmark displacement method has been widely used to study the earthquake-induced landslides and adopted to explore the initiation and kinematics of catastrophic planar failure in recent years. However, surprisingly few researchers utilize the Newmark displacement method to study the earthquake-induced wedge slide. The classical Newmark displacement method for earthquake-induced wedge sliding assumed the wedge is rigid and the vertical acceleration, as well as the horizontal acceleration perpendicular to the sliding direction, is neglected. Moreover, the friction coefficients on the weak planes are assumed as unchanged during sliding. The purpose of this study is to test the reasonableness of the aforementioned assumptions. This study uses Newmark displacement method incorporating the rigid wedge method (RWM) and maximum shear stress method (MSSM) to evaluate the influence of wedge deformation. We design the geometry of the wedge and input the synthetic seismicity to trigger the wedge slide. The influence for neglecting the vertical and horizontal (perpendicular to the sliding direction) accelerations is also assessed. Besides, this research incorporates the velocity-displacement dependent friction law in the analysis to evaluate the influence of constant friction coefficient assumption. Result of this study illustrated that the aforementioned assumptions have significant effects on the calculated permeant displacement, moving speed, and failure initiation. To conclude, this study provides new insights on the initiation and kinematics of an earthquake induced wedge slide.

  16. Immediate and 1 week effects of laterally wedge insoles on gait biomechanics in healthy females.

    PubMed

    Weinhandl, Joshua T; Sudheimer, Sarah E; Van Lunen, Bonnie L; Stewart, Kimberly; Hoch, Matthew C

    2016-03-01

    It is estimated that approximately 45% of the U.S. population will develop knee osteoarthritis, a disease that creates significant economic burdens in both direct and indirect costs. Laterally wedged insoles have been frequently recommended to reduce knee abduction moments and to manage knee osteoarthritis. However, it remains unknown whether the lateral wedge will reduce knee abduction moments over a prolonged period of time. Thus, the purposes of this study were to (1) examine the immediate effects of a laterally wedged insole in individuals normally aligned knees and (2) determine prolonged effects after the insole was worn for 1 week. Gait analysis was performed on ten women with and without a laterally wedged insole. After participants wore the wedges for a week, a second gait analysis was performed with and without the insole. The wedged insole did not affect peak knee abduction moment, although there was a significant increase in knee abduction angular impulse after wearing the insoles for 1 week. Furthermore, there was a significant increase in vertical ground reaction force at the instance of peak knee abduction moment with the wedges. While the laterally wedged insole used in the current study did not alter knee abduction moments as expected, other studies have shown alterations. Future studies should also examine a longer acclimation period, the influence of gait speed, and the effect of different shoe types with the insole.

  17. Preliminary analysis of coil wedge dimensional variation in SSC Prototype Dipole Magnets

    SciTech Connect

    Pollock, D.; Brown, G.; Dwyer, S.; Gattu, R.; Warner, D.

    1993-05-01

    The wedges used in SSC Prototype Dipole Magnets determine the relative position of conductor blocks within magnet coils. They serve to compensate partially for the less than full keystoning of the superconductor cable and to adjust current distribution with azimuth to determine the magnetic field shape. The ability to control the size and uniformity of wedges therefore is an important factor influencing magnet quality. This paper presents preliminary results of a Statistical Quality Control study of wedge dimensional variation and predicted field quality. Dimensions of samples from outer wedges for magnet DCA102 have been measured using a programmable optical comparator. The data is used to evaluate wedge manufacturing process capability, wedge uniformity, and to predict changes in conductor block position due to wedge deviation. Expected multipole variation attributable to observed wedge variation is discussed. This work focuses on a Prototype Dipole Magnet being built at the SSCL Magnet Development Laboratory (SSCL MDL) in Waxahachie, Texas. The magnet is of the same design as the DCA3xx series magnets built at Fermi National Accelerator Laboratory (FNAL) in 1991--92 and later used in the 1992 Accelerator Systems String Test (ASST).

  18. Enhancement of linear and second-order hyperpolarizabilities in wedge-shaped nanostructures

    NASA Astrophysics Data System (ADS)

    Jayabalan, J.; Singh, Manoranjan P.; Rustagi, K. C.

    2003-08-01

    Analytical solutions for the wave functions for free electrons inside a wedge-shaped quantum dot are reported. For silver wedge-shaped quantum dots, linear and second-order hyperpolarizabilities are calculated for various apex angles. It is found that linear and nonlinear hyperpolarizabilities both increase with decreasing apex angle.

  19. Pan-Arctic ice-wedge degradation in warming permafrost and its influence on tundra hydrology

    NASA Astrophysics Data System (ADS)

    Liljedahl, Anna K.; Boike, Julia; Daanen, Ronald P.; Fedorov, Alexander N.; Frost, Gerald V.; Grosse, Guido; Hinzman, Larry D.; Iijma, Yoshihiro; Jorgenson, Janet C.; Matveyeva, Nadya; Necsoiu, Marius; Raynolds, Martha K.; Romanovsky, Vladimir E.; Schulla, Jörg; Tape, Ken D.; Walker, Donald A.; Wilson, Cathy J.; Yabuki, Hironori; Zona, Donatella

    2016-04-01

    Ice wedges are common features of the subsurface in permafrost regions. They develop by repeated frost cracking and ice vein growth over hundreds to thousands of years. Ice-wedge formation causes the archetypal polygonal patterns seen in tundra across the Arctic landscape. Here we use field and remote sensing observations to document polygon succession due to ice-wedge degradation and trough development in ten Arctic localities over sub-decadal timescales. Initial thaw drains polygon centres and forms disconnected troughs that hold isolated ponds. Continued ice-wedge melting leads to increased trough connectivity and an overall draining of the landscape. We find that melting at the tops of ice wedges over recent decades and subsequent decimetre-scale ground subsidence is a widespread Arctic phenomenon. Although permafrost temperatures have been increasing gradually, we find that ice-wedge degradation is occurring on sub-decadal timescales. Our hydrological model simulations show that advanced ice-wedge degradation can significantly alter the water balance of lowland tundra by reducing inundation and increasing runoff, in particular due to changes in snow distribution as troughs form. We predict that ice-wedge degradation and the hydrological changes associated with the resulting differential ground subsidence will expand and amplify in rapidly warming permafrost regions.

  20. Performance of an isolated two-dimensional wedge nozzle with fixed cowl and variable wedge centerbody at Mach numbers up to 2.01

    NASA Technical Reports Server (NTRS)

    Maiden, D. L.

    1976-01-01

    A wind tunnel investigation has been conducted to determine the aeropropulsion performance (thrust minus drag) of an isolated, two-dimensional wedge nozzle with a simulated variable-wedge mechanism and a fixed cowl. The investigation was conducted statically and at Mach numbers from 0.60 to 1.20 in the Langley 16-foot transonic tunnel and at a Mach number of 2.01 in the Langley 4-foot supersonic pressure tunnel. The ratio of exhaust jet total pressure to free-stream static pressure was varied up to 27 depending on free-stream Mach number. The results indicate that the aeropropulsion performance of the two-dimensional fixed-cowl variable-wedge nozzle is slightly lower (0.7 to 1.4 percent of ideal thrust) than that achieved for a two-dimensional wedge nozzle with a translating shroud, although part of the difference in performance is attributed to internal-performance differences. The effects of cowl boattail angle, internal expansion area ratio, and wedge half-angle on the performance of the two-dimensional wedge nozzle are discussed.

  1. OpenTopography: Enabling Online Access to High-Resolution Lidar Topography Data and Processing Tools

    NASA Astrophysics Data System (ADS)

    Crosby, Christopher; Nandigam, Viswanath; Baru, Chaitan; Arrowsmith, J. Ramon

    2013-04-01

    High-resolution topography data acquired with lidar (light detection and ranging) technology are revolutionizing the way we study the Earth's surface and overlying vegetation. These data, collected from airborne, tripod, or mobile-mounted scanners have emerged as a fundamental tool for research on topics ranging from earthquake hazards to hillslope processes. Lidar data provide a digital representation of the earth's surface at a resolution sufficient to appropriately capture the processes that contribute to landscape evolution. The U.S. National Science Foundation-funded OpenTopography Facility (http://www.opentopography.org) is a web-based system designed to democratize access to earth science-oriented lidar topography data. OpenTopography provides free, online access to lidar data in a number of forms, including the raw point cloud and associated geospatial-processing tools for customized analysis. The point cloud data are co-located with on-demand processing tools to generate digital elevation models, and derived products and visualizations which allow users to quickly access data in a format appropriate for their scientific application. The OpenTopography system is built using a service-oriented architecture (SOA) that leverages cyberinfrastructure resources at the San Diego Supercomputer Center at the University of California San Diego to allow users, regardless of expertise level, to access these massive lidar datasets and derived products for use in research and teaching. OpenTopography hosts over 500 billion lidar returns covering 85,000 km2. These data are all in the public domain and are provided by a variety of partners under joint agreements and memoranda of understanding with OpenTopography. Partners include national facilities such as the NSF-funded National Center for Airborne Lidar Mapping (NCALM), as well as non-governmental organizations and local, state, and federal agencies. OpenTopography has become a hub for high-resolution topography

  2. Image Harvest: an open-source platform for high-throughput plant image processing and analysis

    PubMed Central

    Knecht, Avi C.; Campbell, Malachy T.; Caprez, Adam; Swanson, David R.; Walia, Harkamal

    2016-01-01

    High-throughput plant phenotyping is an effective approach to bridge the genotype-to-phenotype gap in crops. Phenomics experiments typically result in large-scale image datasets, which are not amenable for processing on desktop computers, thus creating a bottleneck in the image-analysis pipeline. Here, we present an open-source, flexible image-analysis framework, called Image Harvest (IH), for processing images originating from high-throughput plant phenotyping platforms. Image Harvest is developed to perform parallel processing on computing grids and provides an integrated feature for metadata extraction from large-scale file organization. Moreover, the integration of IH with the Open Science Grid provides academic researchers with the computational resources required for processing large image datasets at no cost. Image Harvest also offers functionalities to extract digital traits from images to interpret plant architecture-related characteristics. To demonstrate the applications of these digital traits, a rice (Oryza sativa) diversity panel was phenotyped and genome-wide association mapping was performed using digital traits that are used to describe different plant ideotypes. Three major quantitative trait loci were identified on rice chromosomes 4 and 6, which co-localize with quantitative trait loci known to regulate agronomically important traits in rice. Image Harvest is an open-source software for high-throughput image processing that requires a minimal learning curve for plant biologists to analyzephenomics datasets. PMID:27141917

  3. Image Harvest: an open-source platform for high-throughput plant image processing and analysis.

    PubMed

    Knecht, Avi C; Campbell, Malachy T; Caprez, Adam; Swanson, David R; Walia, Harkamal

    2016-05-01

    High-throughput plant phenotyping is an effective approach to bridge the genotype-to-phenotype gap in crops. Phenomics experiments typically result in large-scale image datasets, which are not amenable for processing on desktop computers, thus creating a bottleneck in the image-analysis pipeline. Here, we present an open-source, flexible image-analysis framework, called Image Harvest (IH), for processing images originating from high-throughput plant phenotyping platforms. Image Harvest is developed to perform parallel processing on computing grids and provides an integrated feature for metadata extraction from large-scale file organization. Moreover, the integration of IH with the Open Science Grid provides academic researchers with the computational resources required for processing large image datasets at no cost. Image Harvest also offers functionalities to extract digital traits from images to interpret plant architecture-related characteristics. To demonstrate the applications of these digital traits, a rice (Oryza sativa) diversity panel was phenotyped and genome-wide association mapping was performed using digital traits that are used to describe different plant ideotypes. Three major quantitative trait loci were identified on rice chromosomes 4 and 6, which co-localize with quantitative trait loci known to regulate agronomically important traits in rice. Image Harvest is an open-source software for high-throughput image processing that requires a minimal learning curve for plant biologists to analyzephenomics datasets.

  4. Image Harvest: an open-source platform for high-throughput plant image processing and analysis.

    PubMed

    Knecht, Avi C; Campbell, Malachy T; Caprez, Adam; Swanson, David R; Walia, Harkamal

    2016-05-01

    High-throughput plant phenotyping is an effective approach to bridge the genotype-to-phenotype gap in crops. Phenomics experiments typically result in large-scale image datasets, which are not amenable for processing on desktop computers, thus creating a bottleneck in the image-analysis pipeline. Here, we present an open-source, flexible image-analysis framework, called Image Harvest (IH), for processing images originating from high-throughput plant phenotyping platforms. Image Harvest is developed to perform parallel processing on computing grids and provides an integrated feature for metadata extraction from large-scale file organization. Moreover, the integration of IH with the Open Science Grid provides academic researchers with the computational resources required for processing large image datasets at no cost. Image Harvest also offers functionalities to extract digital traits from images to interpret plant architecture-related characteristics. To demonstrate the applications of these digital traits, a rice (Oryza sativa) diversity panel was phenotyped and genome-wide association mapping was performed using digital traits that are used to describe different plant ideotypes. Three major quantitative trait loci were identified on rice chromosomes 4 and 6, which co-localize with quantitative trait loci known to regulate agronomically important traits in rice. Image Harvest is an open-source software for high-throughput image processing that requires a minimal learning curve for plant biologists to analyzephenomics datasets. PMID:27141917

  5. Comparison of the hamstring/quadriceps ratio in females during squat exercise using various foot wedges.

    PubMed

    Yoo, Won-Gyu

    2016-08-01

    [Purpose] This study compared the hamstring/quadriceps ratio in females during squat exercise using various foot wedges. [Subjects and Methods] Nine females participated in this study. Surface electrodes measurements were taken over the hamstring and quadriceps under 3 squat exercise conditions, and the hamstring/quadriceps ratio was calculated. [Results] The hamstring/quadriceps ratio was significantly increased during squat exercise in inclined wedge condition (7.4 ± 1.8), compared to the declined wedge condition (5.3 ± 2.2) and no wedge condition (6.4 ± 3.2). [Conclusion] This study suggests that squat exercise in the inclined wedge condition may be effective for increasing the hamstring/quadriceps ratio in females. PMID:27630437

  6. Periodic nanostructures from self assembled wedge-type block-copolymers

    DOEpatents

    Xia, Yan; Sveinbjornsson, Benjamin R.; Grubbs, Robert H.; Weitekamp, Raymond; Miyake, Garret M.; Piunova, Victoria; Daeffler, Christopher Scot

    2015-06-02

    The invention provides a class of wedge-type block copolymers having a plurality of chemically different blocks, at least a portion of which incorporates a wedge group-containing block providing useful properties. For example, use of one or more wedge group-containing blocks in some block copolymers of the invention significantly inhibits chain entanglement and, thus, the present block copolymers materials provide a class of polymer materials capable of efficient molecular self-assembly to generate a range of structures, such as periodic nanostructures and microstructures. Materials of the present invention include copolymers having one or more wedge group-containing blocks, and optionally for some applications copolymers also incorporating one or more polymer side group-containing blocks. The present invention also provides useful methods of making and using wedge-type block copolymers.

  7. Wedge and spring assembly for securing coils in electromagnets and dynamoelectric machines

    DOEpatents

    Lindner, Melvin; Cottingham, James G.

    1996-03-12

    A wedge and spring assembly for use in electromagnets or dynamoelectric machines having a housing with an axis therethrough and a plurality of coils supported on salient poles that extend radially inward from the housing toward the housing axis to define a plurality of interpole spaces. The wedge and spring assembly includes a nonmagnetic retainer spring and a nonmagnetic wedge. The retainer spring is formed to fit into one of the interpole spaces, and has juxtaposed ends defining between them a slit extending in a direction generally parallel to the housing axis. The wedge for insertion into the slit provides an outwardly directed force on respective portions of the juxtaposed ends to expand the slit so that respective portions of the retainer spring engage areas of the coils adjacent thereto, thereby resiliently holding the coils against their respective salient poles. The retainer spring is generally triangular shaped to fit within the interpole space, and the wedge is generally T-shaped.

  8. Comparison of the hamstring/quadriceps ratio in females during squat exercise using various foot wedges

    PubMed Central

    Yoo, Won-gyu

    2016-01-01

    [Purpose] This study compared the hamstring/quadriceps ratio in females during squat exercise using various foot wedges. [Subjects and Methods] Nine females participated in this study. Surface electrodes measurements were taken over the hamstring and quadriceps under 3 squat exercise conditions, and the hamstring/quadriceps ratio was calculated. [Results] The hamstring/quadriceps ratio was significantly increased during squat exercise in inclined wedge condition (7.4 ± 1.8), compared to the declined wedge condition (5.3 ± 2.2) and no wedge condition (6.4 ± 3.2). [Conclusion] This study suggests that squat exercise in the inclined wedge condition may be effective for increasing the hamstring/quadriceps ratio in females.

  9. Mechanics of fold-and-thrust belts and accretionary wedges Cohesive Coulomb theory

    NASA Technical Reports Server (NTRS)

    Dahlen, F. A.; Suppe, J.; Davis, D.

    1984-01-01

    A self-consistent theory for the mechanics of thin-skinned accretionary Coulomb wedges is developed and applied to the active fold-and-thrust belt of western Taiwan. The state of stress everywhere within a critical wedge is determined by solving the static equilibrium equations subject to the appropriate boundary conditions. The influence of wedge cohesion, which gives rise to a concave curvature of the critical topographic surface and affects the orientation of the principal stresses and Coulomb fracture within the wedge, is considered. The shape of the topographic surface and the angles at which thrust faults step up from the basal decollement in the Taiwanese belt is analyzed taking into account the extensive structural and fluid-pressure data available there. It is concluded that the gross geometry and structure of the Taiwan wedge are consistent with normal laboratory frictional and fracture strengths of sedimentary rocks.

  10. Comparison of the hamstring/quadriceps ratio in females during squat exercise using various foot wedges

    PubMed Central

    Yoo, Won-gyu

    2016-01-01

    [Purpose] This study compared the hamstring/quadriceps ratio in females during squat exercise using various foot wedges. [Subjects and Methods] Nine females participated in this study. Surface electrodes measurements were taken over the hamstring and quadriceps under 3 squat exercise conditions, and the hamstring/quadriceps ratio was calculated. [Results] The hamstring/quadriceps ratio was significantly increased during squat exercise in inclined wedge condition (7.4 ± 1.8), compared to the declined wedge condition (5.3 ± 2.2) and no wedge condition (6.4 ± 3.2). [Conclusion] This study suggests that squat exercise in the inclined wedge condition may be effective for increasing the hamstring/quadriceps ratio in females. PMID:27630437

  11. Magnetic quantum well states in ultrathin film and wedge structures

    SciTech Connect

    Li, D.; Bader, S.D.

    1996-04-01

    Magnetic quantum-well (QW) states are probed with angle- and spin-resolved photoemission to address critical issues pertaining to the origin of the giant magnetoresistance (GMR) optimization and oscillatory coupling of magnetic multilayers. Two epitaxial systems are highlighted: Cu/Co(wedge)/Cu(100) and Cr/Fe(100)-whisker. The confinement of Cu sp-QW states by a Co barrier requires a characteristic Co thickness of 2.2 {+-} 0.6 {angstrom}, which is consistent with the interfacial Co thickness reported to optimize the GMR of permalloy-Cu structures. The controversial k-space origin of the 18-{angstrom} long period oscillation in Fe/Cr multilayers is identified by the vector that spans the d-derived lens feature of the Cr Fermi surface, based on the emergence of QW states with 17 {+-} 2 {angstrom} periodicity in this region.

  12. Numerical investigation of shedding partial cavities over a sharp wedge

    NASA Astrophysics Data System (ADS)

    Budich, B.; Neuner, S.; Schmidt, S. J.; Adams, N. A.

    2015-12-01

    In this contribution, we examine transient dynamics and cavitation patterns of periodically shedding partial cavities by numerical simulations. The investigation reproduces reference experiments of the cavitating flow over a sharp wedge. Utilizing a homogeneous mixture model, full compressibility of the two-phase flow of water and water vapor is taken into account by the numerical method. We focus on inertia-dominated mechanisms, thus modeling the flow as inviscid. Based on the assumptions of thermodynamic equilibrium and barotropic flow, the thermodynamic properties are computed from closed-form analytical relations. Emphasis is put on a validation of the employed numerical approach. We demonstrate that computed shedding dynamics are in agreement with the references. Complex flow features observed in the experiments, including cavitating hairpin and horse-shoe vortices, are also predicted by the simulations. Furthermore, a condensation discontinuity occurring during the collapse phase at the trailing portion of the partial cavity is equally obtained.

  13. Metamorphism of peritotites in the mantle wedge above the subduction zone: Hydration of the lithospheric mantle

    NASA Astrophysics Data System (ADS)

    Savelieva, G. N.; Raznitsin, Yu. N.; Merkulova, M. V.

    2016-05-01

    Two areas with different types of hydration (serpentinization), which occurred in two settings distinct in temperatures, pressures, and stresses, are spatially individualized in the ophiolitic ultramafic massifs of the Polar Urals. The high-temperature hydration of ultramafic rocks occurred in the lithosphere of the mantle wedge directly above the subducted slab. The initial conditions of hydration are limited to 1.2-2 GPa and 650-700°C; a stable assemblage of olivine + antigorite + magnetite → amphibole → talc → chlorite was formed at 0.9-1.2 GPa and 550-600°C. The low-temperature mesh lizardite-chrysotile serpentinization occurred in the crustal, near-surface conditions. Both types of hydration were accompanied by release of hydrogen, which participates in abiogenic CH4 synthesis in the presence of CO2 dissolved in water.

  14. Distribution of strain rates in the Taiwan orogenic wedge

    NASA Astrophysics Data System (ADS)

    Mouthereau, F.; Fillon, C.; Ma, K.-F.

    2009-07-01

    To constrain the way Eurasian crust is accreted to the Taiwan orogenic wedge we investigate the present-day 3D seismogenic deformation field using the summation of 1129 seismic moment tensors of events ( Mw > 4) covering a period of 11 years (1995 to 2005). Based on the analysis of the principal strain-rate field, including dilatation and maximum shear rates, we distinguish four domains. Domain I comprises the Coastal Plain and the Western Foothills. It is mainly contractional in both the horizontal plane and in cross-section. Domain II comprises the eastern Western Foothills, the Hsuehshan Range and the Backbone Range. It is characterized by the highest contraction rates of 10 - 6 yr - 1 in association with area expansion in cross-section and area contraction in the horizontal plane. Domain III corresponds to the Central Range. It is characterized by area contraction in cross-section and area expansion in the horizontal plane. The maximum contractional axis is typically low and plunges ~ 30°E. Extension is larger, horizontal and strikes parallel to the axis of the mountain range. Domain IV corresponding to the Coastal Range and offshore Luzon Arc shows deformation patterns similar to domain II. This seismogenic strain-rate field, which is found in good agreement with the main features of the geodetic field, supports shortening within a thick wedge whose basal décollement is relatively flat and located in the middle-to-lower crust > 20 km. The east plunges of maximum strain-rate axes below the Central Range argue for the development of top-to-the-east transport of rocks resulting from the extrusion of the whole crust along west-dipping crustal-scale shear zones. The study of seismogenic strain rates argues that the initiation of subduction reversal has already started in the Taiwan collision domain.

  15. The Substorm Current Wedge: Further Insights from MHD Simulations

    NASA Technical Reports Server (NTRS)

    Birn, J.; Hesse, M.

    2015-01-01

    Using a recent magnetohydrodynamic simulation of magnetotail dynamics, we further investigate the buildup and evolution of the substorm current wedge (SCW), resulting from flow bursts generated by near-tail reconnection. Each flow burst generates an individual current wedge, which includes the reduction of cross-tail current and the diversion to region 1 (R1)-type field-aligned currents (earthward on the dawn and tailward on the duskside), connecting the tail with the ionosphere. Multiple flow bursts generate initially multiple SCW patterns, which at later times combine to a wider single SCW pattern. The standard SCWmodel is modified by the addition of several current loops, related to particular magnetic field changes: the increase of Bz in a local equatorial region (dipolarization), the decrease of |Bx| away from the equator (current disruption), and increases in |By| resulting from azimuthally deflected flows. The associated loop currents are found to be of similar magnitude, 0.1-0.3 MA. The combined effect requires the addition of region 2 (R2)-type currents closing in the near tail through dawnward currents but also connecting radially with the R1 currents. The current closure at the inner boundary, taken as a crude proxy of an idealized ionosphere, demonstrates westward currents as postulated in the original SCW picture as well as North-South currents connecting R1- and R2-type currents, which were larger than the westward currents by a factor of almost 2. However, this result should be applied with caution to the ionosphere because of our neglect of finite resistance and Hall effects.

  16. Thrust fault growth within accretionary wedges: New Insights from 3D seismic reflection data

    NASA Astrophysics Data System (ADS)

    Orme, H.; Bell, R. E.; Jackson, C. A. L.

    2015-12-01

    The shallow parts of subduction megathrust faults are typically thought to be aseismic and incapable of propagating seismic rupture. The 2011 Tohoku-Oki earthquake, however, ruptured all the way to the trench, proving that in some locations rupture can propagate through the accretionary wedge. An improved understanding of the structural character and physical properties of accretionary wedges is therefore crucial to begin to assess why such anomalously shallow seismic rupture occurs. Despite its importance, we know surprisingly little regarding the 3D geometry and kinematics of thrust network development in accretionary prisms, largely due to a lack of 3D seismic reflection data providing high-resolution, 3D images of entire networks. Thus our current understanding is largely underpinned by observations from analogue and numerical modelling, with limited observational data from natural examples. In this contribution we use PSDM, 3D seismic reflection data from the Nankai margin (3D Muroto dataset, available from the UTIG Academic Seismic Portal, Marine Geoscience Data System) to examine how imbricate thrust fault networks evolve during accretionary wedge growth. Previous studies have reported en-echelon thrust fault geometries from the NW part of the dataset, and have related this complex structure to seamount subduction. We unravel the evolution of faults within the protothrust and imbricate thrust zones by interpreting multiple horizons across faults and measuring fault displacement and fold amplitude along-strike; by doing this, we are able to investigate the three dimensional accrual of strain. We document a number of local displacement minima along-strike of faults, suggesting that, the protothrust and imbricate thrusts developed from the linkage of smaller, previously isolated fault segments. We also demonstrate that the majority of faults grew upward from the décollement, although there is some evidence for downward fault propagation. Our observations

  17. Deriving Animal Behaviour from High-Frequency GPS: Tracking Cows in Open and Forested Habitat

    PubMed Central

    de Weerd, Nelleke; van Langevelde, Frank; van Oeveren, Herman; Nolet, Bart A.; Kölzsch, Andrea; Prins, Herbert H. T.; de Boer, W. Fred

    2015-01-01

    The increasing spatiotemporal accuracy of Global Navigation Satellite Systems (GNSS) tracking systems opens the possibility to infer animal behaviour from tracking data. We studied the relationship between high-frequency GNSS data and behaviour, aimed at developing an easily interpretable classification method to infer behaviour from location data. Behavioural observations were carried out during tracking of cows (Bos Taurus) fitted with high-frequency GPS (Global Positioning System) receivers. Data were obtained in an open field and forested area, and movement metrics were calculated for 1 min, 12 s and 2 s intervals. We observed four behaviour types (Foraging, Lying, Standing and Walking). We subsequently used Classification and Regression Trees to classify the simultaneously obtained GPS data as these behaviour types, based on distances and turning angles between fixes. GPS data with a 1 min interval from the open field was classified correctly for more than 70% of the samples. Data from the 12 s and 2 s interval could not be classified successfully, emphasizing that the interval should be long enough for the behaviour to be defined by its characteristic movement metrics. Data obtained in the forested area were classified with a lower accuracy (57%) than the data from the open field, due to a larger positional error of GPS locations and differences in behavioural performance influenced by the habitat type. This demonstrates the importance of understanding the relationship between behaviour and movement metrics, derived from GNSS fixes at different frequencies and in different habitats, in order to successfully infer behaviour. When spatially accurate location data can be obtained, behaviour can be inferred from high-frequency GNSS fixes by calculating simple movement metrics and using easily interpretable decision trees. This allows for the combined study of animal behaviour and habitat use based on location data, and might make it possible to detect deviations

  18. Deriving Animal Behaviour from High-Frequency GPS: Tracking Cows in Open and Forested Habitat.

    PubMed

    de Weerd, Nelleke; van Langevelde, Frank; van Oeveren, Herman; Nolet, Bart A; Kölzsch, Andrea; Prins, Herbert H T; de Boer, W Fred

    2015-01-01

    The increasing spatiotemporal accuracy of Global Navigation Satellite Systems (GNSS) tracking systems opens the possibility to infer animal behaviour from tracking data. We studied the relationship between high-frequency GNSS data and behaviour, aimed at developing an easily interpretable classification method to infer behaviour from location data. Behavioural observations were carried out during tracking of cows (Bos Taurus) fitted with high-frequency GPS (Global Positioning System) receivers. Data were obtained in an open field and forested area, and movement metrics were calculated for 1 min, 12 s and 2 s intervals. We observed four behaviour types (Foraging, Lying, Standing and Walking). We subsequently used Classification and Regression Trees to classify the simultaneously obtained GPS data as these behaviour types, based on distances and turning angles between fixes. GPS data with a 1 min interval from the open field was classified correctly for more than 70% of the samples. Data from the 12 s and 2 s interval could not be classified successfully, emphasizing that the interval should be long enough for the behaviour to be defined by its characteristic movement metrics. Data obtained in the forested area were classified with a lower accuracy (57%) than the data from the open field, due to a larger positional error of GPS locations and differences in behavioural performance influenced by the habitat type. This demonstrates the importance of understanding the relationship between behaviour and movement metrics, derived from GNSS fixes at different frequencies and in different habitats, in order to successfully infer behaviour. When spatially accurate location data can be obtained, behaviour can be inferred from high-frequency GNSS fixes by calculating simple movement metrics and using easily interpretable decision trees. This allows for the combined study of animal behaviour and habitat use based on location data, and might make it possible to detect deviations

  19. OpenMSI: a high-performance web-based platform for mass spectrometry imaging.

    PubMed

    Rübel, Oliver; Greiner, Annette; Cholia, Shreyas; Louie, Katherine; Bethel, E Wes; Northen, Trent R; Bowen, Benjamin P

    2013-11-01

    Mass spectrometry imaging (MSI) enables researchers to directly probe endogenous molecules directly within the architecture of the biological matrix. Unfortunately, efficient access, management, and analysis of the data generated by MSI approaches remain major challenges to this rapidly developing field. Despite the availability of numerous dedicated file formats and software packages, it is a widely held viewpoint that the biggest challenge is simply opening, sharing, and analyzing a file without loss of information. Here we present OpenMSI, a software framework and platform that addresses these challenges via an advanced, high-performance, extensible file format and Web API for remote data access (http://openmsi.nersc.gov). The OpenMSI file format supports storage of raw MSI data, metadata, and derived analyses in a single, self-describing format based on HDF5 and is supported by a large range of analysis software (e.g., Matlab and R) and programming languages (e.g., C++, Fortran, and Python). Careful optimization of the storage layout of MSI data sets using chunking, compression, and data replication accelerates common, selective data access operations while minimizing data storage requirements and are critical enablers of rapid data I/O. The OpenMSI file format has shown to provide >2000-fold improvement for image access operations, enabling spectrum and image retrieval in less than 0.3 s across the Internet even for 50 GB MSI data sets. To make remote high-performance compute resources accessible for analysis and to facilitate data sharing and collaboration, we describe an easy-to-use yet powerful Web API, enabling fast and convenient access to MSI data, metadata, and derived analysis results stored remotely to facilitate high-performance data analysis and enable implementation of Web based data sharing, visualization, and analysis. PMID:24087878

  20. OpenMSI: A High-Performance Web-Based Platform for Mass Spectrometry Imaging

    SciTech Connect

    Rubel, Oliver; Greiner, Annette; Cholia, Shreyas; Louie, Katherine; Bethel, E. Wes; Northen, Trent R.; Bowen, Benjamin P.

    2013-10-02

    Mass spectrometry imaging (MSI) enables researchers to directly probe endogenous molecules directly within the architecture of the biological matrix. Unfortunately, efficient access, management, and analysis of the data generated by MSI approaches remain major challenges to this rapidly developing field. Despite the availability of numerous dedicated file formats and software packages, it is a widely held viewpoint that the biggest challenge is simply opening, sharing, and analyzing a file without loss of information. Here we present OpenMSI, a software framework and platform that addresses these challenges via an advanced, high-performance, extensible file format and Web API for remote data access (http://openmsi.nersc.gov). The OpenMSI file format supports storage of raw MSI data, metadata, and derived analyses in a single, self-describing format based on HDF5 and is supported by a large range of analysis software (e.g., Matlab and R) and programming languages (e.g., C++, Fortran, and Python). Careful optimization of the storage layout of MSI data sets using chunking, compression, and data replication accelerates common, selective data access operations while minimizing data storage requirements and are critical enablers of rapid data I/O. The OpenMSI file format has shown to provide >2000-fold improvement for image access operations, enabling spectrum and image retrieval in less than 0.3 s across the Internet even for 50 GB MSI data sets. To make remote high-performance compute resources accessible for analysis and to facilitate data sharing and collaboration, we describe an easy-to-use yet powerful Web API, enabling fast and convenient access to MSI data, metadata, and derived analysis results stored remotely to facilitate high-performance data analysis and enable implementation of Web based data sharing, visualization, and analysis.

  1. High tibial osteotomy in varus knees: indications and limits

    PubMed Central

    LOIA, MARCO CORGIAT; VANNI, STEFANIA; ROSSO, FEDERICA; BONASIA, DAVIDE EDOARDO; BRUZZONE, MATTEO; DETTONI, FEDERICO; ROSSI, ROBERTO

    2016-01-01

    Opening wedge high tibial osteotomy (OWHTO) is a surgical procedure that aims to correct the weight-bearing axis of the knee, moving the loads laterally from the medial compartment. Conventional indications for OWHTO are medial compartment osteoarthritis and varus malalignment of the knee; recently OWHTO has been used successfully in the treatment of double and triple varus. OWHTO, in contrast to closing wedge high tibial osteotomy, does not require fibular osteotomy or peroneal nerve dissection, or lead to disruption of the proximal tibiofibular joint and bone stock loss. For these reasons, interest in this procedure has grown in recent years. The aim of this study is to review the literature on OWHTO, considering indications and prognostic factors (body mass index, grade of osteoarthritis, instability, range of movement and age), outcomes at mid-term follow-up, and limits of the procedure (slope modifications, patellar height changes and difficulties in conversion to a total knee arthroplasty). PMID:27602350

  2. High tibial osteotomy in varus knees: indications and limits

    PubMed Central

    LOIA, MARCO CORGIAT; VANNI, STEFANIA; ROSSO, FEDERICA; BONASIA, DAVIDE EDOARDO; BRUZZONE, MATTEO; DETTONI, FEDERICO; ROSSI, ROBERTO

    2016-01-01

    Opening wedge high tibial osteotomy (OWHTO) is a surgical procedure that aims to correct the weight-bearing axis of the knee, moving the loads laterally from the medial compartment. Conventional indications for OWHTO are medial compartment osteoarthritis and varus malalignment of the knee; recently OWHTO has been used successfully in the treatment of double and triple varus. OWHTO, in contrast to closing wedge high tibial osteotomy, does not require fibular osteotomy or peroneal nerve dissection, or lead to disruption of the proximal tibiofibular joint and bone stock loss. For these reasons, interest in this procedure has grown in recent years. The aim of this study is to review the literature on OWHTO, considering indications and prognostic factors (body mass index, grade of osteoarthritis, instability, range of movement and age), outcomes at mid-term follow-up, and limits of the procedure (slope modifications, patellar height changes and difficulties in conversion to a total knee arthroplasty).

  3. High tibial osteotomy in varus knees: indications and limits.

    PubMed

    Loia, Marco Corgiat; Vanni, Stefania; Rosso, Federica; Bonasia, Davide Edoardo; Bruzzone, Matteo; Dettoni, Federico; Rossi, Roberto

    2016-01-01

    Opening wedge high tibial osteotomy (OWHTO) is a surgical procedure that aims to correct the weight-bearing axis of the knee, moving the loads laterally from the medial compartment. Conventional indications for OWHTO are medial compartment osteoarthritis and varus malalignment of the knee; recently OWHTO has been used successfully in the treatment of double and triple varus. OWHTO, in contrast to closing wedge high tibial osteotomy, does not require fibular osteotomy or peroneal nerve dissection, or lead to disruption of the proximal tibiofibular joint and bone stock loss. For these reasons, interest in this procedure has grown in recent years. The aim of this study is to review the literature on OWHTO, considering indications and prognostic factors (body mass index, grade of osteoarthritis, instability, range of movement and age), outcomes at mid-term follow-up, and limits of the procedure (slope modifications, patellar height changes and difficulties in conversion to a total knee arthroplasty). PMID:27602350

  4. Vertebral body or intervertebral disc wedging: which contributes more to thoracolumbar kyphosis in ankylosing spondylitis patients?

    PubMed Central

    Liu, Hao; Qian, Bang-Ping; Qiu, Yong; Wang, Yan; Wang, Bin; Yu, Yang; Zhu, Ze-Zhang

    2016-01-01

    Abstract Both vertebral body wedging and disc wedging are found in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis. However, their relative contribution to thoracolumbar kyphosis is not fully understood. The objective of this study was to compare different contributions of vertebral and disc wedging to the thoracolumbar kyphosis in AS patients, and to analyze the relationship between the apical vertebral wedging angle and thoracolumbar kyphosis. From October 2009 to October 2013, a total of 59 consecutive AS patients with thoracolumbar kyphosis with a mean age of 38.1 years were recruited in this study. Based on global kyphosis (GK), 26 patients with GK < 70° were assigned to group A, and the other 33 patients with GK ≥ 70° were included in group B. Each GK was divided into disc wedge angles and vertebral wedge angles. The wedging angle of each disc and vertebra comprising the thoracolumbar kyphosis was measured, and the proportion of the wedging angle to the GK was calculated accordingly. Intergroup and intragroup comparisons were subsequently performed to investigate the different contributions of disc and vertebra to the GK. The correlation between the apical vertebral wedging angle and GK was calculated by Pearson correlation analysis. The duration of disease and sex were also recorded in this study. With respect to the mean disease duration, significant difference was observed between the two groups (P < 0.01). The wedging angle and wedging percentage of discs were significantly higher than those of vertebrae in group A (34.8° ± 2.5° vs 26.7° ± 2.7°, P < 0.01 and 56.6% vs 43.4%, P < 0.01), whereas disc wedging and disc wedging percentage were significantly lower than vertebrae in group B (37.6° ± 7.0° vs 50.1° ± 5.1°, P < 0.01 and 42.7% vs 57.3%, P < 0.01). The wedging of vertebrae was significantly higher in group B than in group A (50.1° ± 5.1° vs 26.7° ± 2.7°, P < 0

  5. Fluids confined in wedges and by edges: Virial series for the line-thermodynamic properties of hard spheres

    NASA Astrophysics Data System (ADS)

    Urrutia, Ignacio

    2014-12-01

    This work is devoted to analyze the relation between the thermodynamic properties of a confined fluid and the shape of its confining vessel. Recently, new insights in this topic were found through the study of cluster integrals for inhomogeneous fluids that revealed the dependence on the vessel shape of the low density behavior of the system. Here, the statistical mechanics and thermodynamics of fluids confined in wedges or by edges is revisited, focusing on their cluster integrals. In particular, the well known hard sphere fluid, which was not studied in this framework so far, is analyzed under confinement and its thermodynamic properties are analytically studied up to order two in the density. Furthermore, the analysis is extended to the confinement produced by a corrugated wall. These results rely on the obtained analytic expression for the second cluster integral of the confined hard sphere system as a function of the opening dihedral angle 0 < β < 2π. It enables a unified approach to both wedges and edges.

  6. Fluids confined in wedges and by edges: Virial series for the line-thermodynamic properties of hard spheres

    SciTech Connect

    Urrutia, Ignacio

    2014-12-28

    This work is devoted to analyze the relation between the thermodynamic properties of a confined fluid and the shape of its confining vessel. Recently, new insights in this topic were found through the study of cluster integrals for inhomogeneous fluids that revealed the dependence on the vessel shape of the low density behavior of the system. Here, the statistical mechanics and thermodynamics of fluids confined in wedges or by edges is revisited, focusing on their cluster integrals. In particular, the well known hard sphere fluid, which was not studied in this framework so far, is analyzed under confinement and its thermodynamic properties are analytically studied up to order two in the density. Furthermore, the analysis is extended to the confinement produced by a corrugated wall. These results rely on the obtained analytic expression for the second cluster integral of the confined hard sphere system as a function of the opening dihedral angle 0 < β < 2π. It enables a unified approach to both wedges and edges.

  7. Scalable High Performance Message Passing over InfiniBand for Open MPI

    SciTech Connect

    Friedley, A; Hoefler, T; Leininger, M L; Lumsdaine, A

    2007-10-24

    InfiniBand (IB) is a popular network technology for modern high-performance computing systems. MPI implementations traditionally support IB using a reliable, connection-oriented (RC) transport. However, per-process resource usage that grows linearly with the number of processes, makes this approach prohibitive for large-scale systems. IB provides an alternative in the form of a connectionless unreliable datagram transport (UD), which allows for near-constant resource usage and initialization overhead as the process count increases. This paper describes a UD-based implementation for IB in Open MPI as a scalable alternative to existing RC-based schemes. We use the software reliability capabilities of Open MPI to provide the guaranteed delivery semantics required by MPI. Results show that UD not only requires fewer resources at scale, but also allows for shorter MPI startup times. A connectionless model also improves performance for applications that tend to send small messages to many different processes.

  8. tranSMART: An Open Source Knowledge Management and High Content Data Analytics Platform

    PubMed Central

    Scheufele, Elisabeth; Aronzon, Dina; Coopersmith, Robert; McDuffie, Michael T.; Kapoor, Manish; Uhrich, Christopher A.; Avitabile, Jean E.; Liu, Jinlei; Housman, Dan; Palchuk, Matvey B.

    2014-01-01

    The tranSMART knowledge management and high-content analysis platform is a flexible software framework featuring novel research capabilities. It enables analysis of integrated data for the purposes of hypothesis generation, hypothesis validation, and cohort discovery in translational research. tranSMART bridges the prolific world of basic science and clinical practice data at the point of care by merging multiple types of data from disparate sources into a common environment. The application supports data harmonization and integration with analytical pipelines. The application code was released into the open source community in January 2012, with 32 instances in operation. tranSMART’s extensible data model and corresponding data integration processes, rapid data analysis features, and open source nature make it an indispensable tool in translational or clinical research. PMID:25717408

  9. Exploring Infiniband Hardware Virtualization in OpenNebula towards Efficient High-Performance Computing

    SciTech Connect

    Pais Pitta de Lacerda Ruivo, Tiago; Bernabeu Altayo, Gerard; Garzoglio, Gabriele; Timm, Steven; Kim, Hyun-Woo; Noh, Seo-Young; Raicu, Ioan

    2014-11-11

    has been widely accepted that software virtualization has a big negative impact on high-performance computing (HPC) application performance. This work explores the potential use of Infiniband hardware virtualization in an OpenNebula cloud towards the efficient support of MPI-based workloads. We have implemented, deployed, and tested an Infiniband network on the FermiCloud private Infrastructure-as-a-Service (IaaS) cloud. To avoid software virtualization towards minimizing the virtualization overhead, we employed a technique called Single Root Input/Output Virtualization (SRIOV). Our solution spanned modifications to the Linux’s Hypervisor as well as the OpenNebula manager. We evaluated the performance of the hardware virtualization on up to 56 virtual machines connected by up to 8 DDR Infiniband network links, with micro-benchmarks (latency and bandwidth) as well as w a MPI-intensive application (the HPL Linpack benchmark).

  10. tranSMART: An Open Source Knowledge Management and High Content Data Analytics Platform.

    PubMed

    Scheufele, Elisabeth; Aronzon, Dina; Coopersmith, Robert; McDuffie, Michael T; Kapoor, Manish; Uhrich, Christopher A; Avitabile, Jean E; Liu, Jinlei; Housman, Dan; Palchuk, Matvey B

    2014-01-01

    The tranSMART knowledge management and high-content analysis platform is a flexible software framework featuring novel research capabilities. It enables analysis of integrated data for the purposes of hypothesis generation, hypothesis validation, and cohort discovery in translational research. tranSMART bridges the prolific world of basic science and clinical practice data at the point of care by merging multiple types of data from disparate sources into a common environment. The application supports data harmonization and integration with analytical pipelines. The application code was released into the open source community in January 2012, with 32 instances in operation. tranSMART's extensible data model and corresponding data integration processes, rapid data analysis features, and open source nature make it an indispensable tool in translational or clinical research. PMID:25717408

  11. Open Source Drug Discovery: Highly Potent Antimalarial Compounds Derived from the Tres Cantos Arylpyrroles

    PubMed Central

    2016-01-01

    The development of new antimalarial compounds remains a pivotal part of the strategy for malaria elimination. Recent large-scale phenotypic screens have provided a wealth of potential starting points for hit-to-lead campaigns. One such public set is explored, employing an open source research mechanism in which all data and ideas were shared in real time, anyone was able to participate, and patents were not sought. One chemical subseries was found to exhibit oral activity but contained a labile ester that could not be replaced without loss of activity, and the original hit exhibited remarkable sensitivity to minor structural change. A second subseries displayed high potency, including activity within gametocyte and liver stage assays, but at the cost of low solubility. As an open source research project, unexplored avenues are clearly identified and may be explored further by the community; new findings may be cumulatively added to the present work. PMID:27800551

  12. tranSMART: An Open Source Knowledge Management and High Content Data Analytics Platform.

    PubMed

    Scheufele, Elisabeth; Aronzon, Dina; Coopersmith, Robert; McDuffie, Michael T; Kapoor, Manish; Uhrich, Christopher A; Avitabile, Jean E; Liu, Jinlei; Housman, Dan; Palchuk, Matvey B

    2014-01-01

    The tranSMART knowledge management and high-content analysis platform is a flexible software framework featuring novel research capabilities. It enables analysis of integrated data for the purposes of hypothesis generation, hypothesis validation, and cohort discovery in translational research. tranSMART bridges the prolific world of basic science and clinical practice data at the point of care by merging multiple types of data from disparate sources into a common environment. The application supports data harmonization and integration with analytical pipelines. The application code was released into the open source community in January 2012, with 32 instances in operation. tranSMART's extensible data model and corresponding data integration processes, rapid data analysis features, and open source nature make it an indispensable tool in translational or clinical research.

  13. The Eocimmerian history of Central Iran: the accretionary wedge of Anarak

    NASA Astrophysics Data System (ADS)

    Malaspina, Nadia; Zanchi, Andrea; Berra, Fabrizio; Javadi, Hamid Reza; Koohpeyma, Meysam; Ghassemi, Mohammad R.; Sheikholeslami, Mohammad Reza; Bergomi, Maria; Tunesi, Annalisa; Zanchetta, Stefano

    2013-04-01

    The Anarak region of Central Iran is a key area for the understanding of the Late Palaeozoic to Triassic Cimmerian evolution of Iran. The Anarak Metamorphic Complex (AMC) forms an E-W trending mountain ridge, which separates the Triassic of Nakhlak to the north from a continuous non-metamorphic Palaeozoic to Mesozoic sedimentary succession to the south and was interpreted as an accretionary wedge active from Late Palaeozoic to Triassic times. The AMC is sharply cross-cut westward by the Upper Cretaceous "Coloured Melange", consisting of low- to medium- grade metamorphic rocks with tectonically intercalated slivers of serpentinite often associated to blue schists. The occurrence of this rock association in Central Iran poses several questions regarding its evolution and especially on the number of Cimmerian (Palaeotethys) sutures (single rather than multiple) between Eurasia and Iran. The AMC includes several subunits (Morghab, Chah Gorbeh, Patyar, Palhavand Gneiss, Lakh Marble and Doshak) which differ for composition and/or metamorphic evolution. Based on field observations, the Morghab and Chah Gorbeh units suggest a common deformation and a similar metamorphic history, characterised by three major folding events. The first two events developed pervasive axial plane foliations causing a complete transposition of the primary stratigraphic characters. Folding was accompanied by two main metamorphic events, the latter showing retrogression from possible medium to low grade conditions. During the third folding stage, large-scale plunging to vertical open folds were superposed on previous folds in the area north of the Kuh-e Chah Gorbeh, deforming the previous penetrative foliations. In this frame, the Palhavand Gneiss can be considered as part of the same metamorphic unit which escaped a more pervasive low grade retrogression. Concerning the Patyar unit, previous studies considered the Lakh Marble as the lagoonal sediments of an atoll. Field analyses indicate that the

  14. Ice-wedge based permafrost chronologies and stable-water isotope records from Arctic Siberia

    NASA Astrophysics Data System (ADS)

    Wetterich, Sebastian; Opel, Thomas; Meyer, Hanno; Schwamborn, Georg; Schirrmeister, Lutz; Dereviagin, Alexander Yu.

    2016-04-01

    Late Quaternary permafrost of northern latitudes contains large proportions of ground ice, including pore ice, segregation ice, massive ice, buried glacier ice and in particular ice wedges. Fossil ice-wedges are remnants of polygonal patterned ground in former tundra areas, which evolved over several tens of thousands of years in non-glaciated Beringia. Ice wedges originate from repeated frost cracking of the ground in winter and subsequent crack filling by snowmelt and re-freezing in the ground in spring. Hence, the stable water isotope composition (δ18O, δD, d excess) of wedge ice derives from winter precipitation and is commonly interpreted as wintertime climate proxy. Paleoclimate studies based on ice-wedge isotope data cover different timescales and periods of the late Quaternary. (MIS 6 to MIS 1). In the long-term scale the temporal resolution is rather low and corresponds to mid- and late Pleistocene and Holocene stratigraphic units. Recent progress has been made in developing centennial Late Glacial and Holocene time series of ice-wedge stable isotopes by applying radiocarbon dating of organic remains in ice samples. Ice wedges exposed at both coasts of the Dmitry Laptev Strait (East Siberian Sea) were studied to deduce winter climate conditions since about 200 kyr. Ice wedges aligned to distinct late Quaternary permafrost strata were studied for their isotopic composition and dated by radiocarbon ages of organic matter within the wedge ice or by cosmogenic nuclide ratios (36Cl/Cl-) of the ice. The paleoclimate interpretation is furthermore based on geocryological and paleoecological proxy data and geochronological information (radiocarbon, luminescence, radioisotope disequilibria 230Th/U) from ice-wedge embedding frozen deposits. Coldest winter conditions are mirrored by most negative δ18O mean values of -37 ‰ and δD mean values of -290 ‰ from ice wedges of the Last Glacial Maximum (26 to 22 kyr BP) while late Holocene (since about 4 kyr BP) and in

  15. Hyper-extended continental crust deformation in the light of Coulomb critical wedge theory

    NASA Astrophysics Data System (ADS)

    Nirrengarten, Michael; Manatschal, Gianreto; Yuan, Xiaoping; Kusznir, Nick; Maillot, Bertrand

    2016-04-01

    The rocks forming the wedge shape termination of hyper-extended continental crust are deformed in the frictional field during the last stage of continental rifting due to cooling and hydration. Seismic interpretation and field evidence show that the basal boundary of the wedge is a low frictional décollement level. The wedge shape, the frictional deformation and the basal décollement correspond to the requirements of the critical Coulomb wedge (CCW) theory which describes the stability limit of a frictional wedge over a décollement. In a simple shear separation model the upper-plate margin (in the hangingwall of the detachment fault) corresponds to a tectonic extensional wedge whereas the lower plate (in the footwall of the detachment fault) is a gravitational wedge. This major difference causes the asymmetry of conjugate hyper-extended rifted margins. We measure a dataset of upper and lower hyper-extended wedge and compare it to the stability envelope of the CCW theory for serpentine and clay friction. We find a good fit by adjusting fluid pressure. The main results of our analysis are that the crustal wedges of lower plate margins are close to the critical shape, which explains their low variability whereas upper plate wedges can be critical, sub- or sup- critical due to the detachment evolution during rifting. On the upper plate side, according to the Coulomb tectonic extensional wedge, faults should be oriented toward the continent. Observations showed some continentward faults in the termination of the continental crust but there are also oceanward faults. This can be explained by two processes, first continentward faults are created only over the detachment, therefore if part of the hyper-extended upper plate crust is not directly over the detachment it will not be part of the wedge. Secondly the tip block of the wedge can be detached creating an extensional allochthon induced by the flattening of the detachment near the surface, therefore continentward

  16. Critical taper wedge strength varies with structural style: results from distinct-element models

    NASA Astrophysics Data System (ADS)

    Strayer, L. M.; Suppe, J.

    2015-12-01

    Critical-taper theory has given diverse insight into kinematics, roles of erosion and sedimentation, and the morphology of compressive mountain belts. We have made progress by recasting the parameter-rich mathematics into a simpler form that describes a linear, co-varying relationship between surface slope and detachment dip (α, β), and internal- and basal-sliding strengths (W, F). Using distinct-element models, we tested this simpler theory over a range of wedge strengths and structural styles. We also obtained W & F from observations of surface slope α and detachment dip β in active natural systems, all of which including the numerical models, show wedges are strong but detachments are weak, with F/W=0.1 or less. Model-derived W & F vary about a mean that matches geometry-derived values. Time- and spatially-averaged dynamical F & W are observed to be equal to wedge-derived results. Critical taper reflects the dynamical strengths during wedge growth and is controlled dynamically as base friction varies between an assigned quasi-static value and lower values during slip events. In the wedge, W varies more than F, which may also be true for natural systems. Detachments have frictional stick/slip behavior on a basal wall, but the wedge has more going on within it. Tandem faulting & folding serve to simultaneously weaken and strengthen the wedge, and may occur anywhere: structural style appears to be important to wedge strength evolution. The dynamics of deformation within the wedge and slip upon the base control the finite wedge geometry: static strengths drop to dynamic levels during seismicity, resulting in materials and faults that are weaker than prescribed in models or determined by testing. Relationships between α and W & F are complex. All sudden, stepwise changes in α, W & F with time coincide with seismicity spikes in the models. Large events trigger or are triggered by large changes in F and W. We examine the complex details of dynamically driven

  17. Deep long-period earthquakes west of the volcanic arc in Oregon: evidence of serpentine dehydration in the fore-arc mantle wedge

    USGS Publications Warehouse

    Vidale, John E.; Schmidt, David A.; Malone, Stephen D.; Hotovec-Ellis, Alicia J.; Moran, Seth C.; Creager, Kenneth C.; Houston, Heidi

    2014-01-01

    Here we report on deep long-period earthquakes (DLPs) newly observed in four places in western Oregon. The DLPs are noteworthy for their location within the subduction fore arc: 40–80 km west of the volcanic arc, well above the slab, and near the Moho. These “offset DLPs” occur near the top of the inferred stagnant mantle wedge, which is likely to be serpentinized and cold. The lack of fore-arc DLPs elsewhere along the arc suggests that localized heating may be dehydrating the serpentinized mantle wedge at these latitudes and causing DLPs by dehydration embrittlement. Higher heat flow in this region could be introduced by anomalously hot mantle, associated with the western migration of volcanism across the High Lava Plains of eastern Oregon, entrained in the corner flow proximal to the mantle wedge. Alternatively, fluids rising from the subducting slab through the mantle wedge may be the source of offset DLPs. As far as we know, these are among the first DLPs to be observed in the fore arc of a subduction-zone system.

  18. Sand provenance documents continuing accretion of the pro-wedge and erosional unroofing of the retro-wedge during arc-continent collision (Taiwan)

    NASA Astrophysics Data System (ADS)

    Garzanti, Eduardo; Padoan, Marta; Resentini, Alberto; Vezzoli, Giovanni; Castelltort, Sebastien; Tien-Shun Lin, Andrew

    2014-05-01

    The Taiwan doubly-vergent orogenic wedge developed during collision between the Luzon volcanic arc and the Chinese passive continental margin since the late Miocene (Byrne et al., 2011). In the east, the Coastal Range represents the northernmost extension of the Luzon arc and includes Neogene volcanic rocks and Plio-Pleistocene siliciclastic deposits. West of the plate boundary, running along the Longitudinal Valley, the Central Range includes polymetamorphic rocks (Tananao Complex) and a Slate Belt (Backbone Range and Hsuehshan Range). Farther to the west, the Western Foothills are a fold-thrust belt incorporating Oligo-Miocene sediments of the Chinese margin and younger foreland-basin deposits. High-resolution framework-petrography and heavy-mineral analyses were carried out on 106 samples collected from major rivers and beaches all around Taiwan in October 2012. The Coastal Range sheds feldspatho-lithic volcaniclastic sands including rich clinopyroxene-hypersthene suites with kaersutitic hornblende. Recycling of Plio-Pleistocene siliciclastics produces quartzo-lithic sands with cellular serpentinite and poor suites including hypersthene, epidote, clinopyroxene, kaersutitic hornblende and rare Cr-spinel. Similar mineralogy characterizes detritus from the Liji Mélange. Sands from the Tananao Complex are quartzo-lithic metamorphiclastic with common marble grains, sporadic metabasite, and moderately rich epidote-hornblende suites. Sands from the Slate Belt are invariably quartzo-lithic with very poor zircon-tourmaline suites. Phyllite and slate grains dominate in the east (Yuli Belt), slate grains in the middle (Backbone Range), and shale/siltstone and slate grains in the northwest (Hsuehshan Range). Neogene strata of the foothills shed litho-quartzose sands with poor suites including zircon, tourmaline, and garnet. Sands from the Tatung volcano are feldspatho-quartzo-lithic with extremely rich hypersthene-clinopyroxene suites including kaersutitic hornblende. The

  19. Inner vs. outer wedge-top depozone "sequences" in the Late Miocene (late Tortonian-early Messinian) Sicilian Foreland Basin System; new data from the Terravecchia Formation of NW Sicily

    NASA Astrophysics Data System (ADS)

    Gugliotta, C.

    2012-04-01

    The wedge-top depozone belongs to the innermost portion of a Foreland Basin System (FBS) (DeCelles and Giles, 1996) and includes all sediments, typically coarse-grained proximal facies, that bury the active frontal part of a fold and thrust belt. The Terravecchia Formation (Flores, 1959; Schmidt Di Friedberg, 1962, 1964-1965; Catalano, 1979) is a composite lithostratigraphic unit widespread in Sicily (southern Italy) which has been recently considered (Gugliotta, 2010) as a part of the stratigraphic record of the Late Miocene (late Tortonian to early Messinian) Sicilian wedge-top depozone and represent the main object of this paper. Two end-member wedge-top "sequences" the (i) the inner wedge-top sequence (IWS) and (ii) the outer wedge-top sequence (OWS), respectively, were recognized in the Terravecchia Formation outcropping in different sectors of NW Sicily and here described and compared on the base of both their depositional and deformative pattern. The differences existing between the IWS and OWS clearly reflect the tectono-depositional evolution of sedimentary basins located at different position across the wedge-top depozone. The more coarse grained and IWS was deposited filling narrow and often oversupplied basins located in the inner sectors of the wedge-top depozone. In these basins the sedimentary evolution has been strongly controlled by a syn-sedimentary transpressional tectonics which produced, since the late Tortonian, the development of "local scale" intraformational angular unconformities. Contemporaneously, the more fine-grained OWS was deposited filling relatively wide and mainly shallow-water marine basins, probably open to major marine areas, located in a less external position of the wedge-top depozone. In these external areas during the late Tortonian-early Messinian the transpressional tectonics was active but still confined to the deeper structural layers producing long wavelength deformation and "basin-scale" unconformities. Integrating

  20. Deformation transients in the brittle regime: Insights from spring-wedge experiments

    NASA Astrophysics Data System (ADS)

    Rosenau, Matthias; Santimano, Tasca; Oncken, Onno

    2016-04-01

    Deformation of the earth's crust varies over timescales ranging from the seismic cycle to plate tectonic phases. Seismic cycles can generically be explained by sudden coseismic release of strain energy accumulated slowly over the interseismic period. The simplest models of such transient behavior is a spring-slider system where the spring stores elastic energy and the slider is characterized by static and dynamic friction at its base allowing cyclic occurrence of slip instabilities. Here we extend this model by allowing the slider to deform in an accretionary wedge type system. Because cyclic thrust formation is associated with bulk strain weakening this should introduce slip instabilities at the time-scale of accretionary cycles superimposed on seismic cycles which are controlled by static and dynamic friction at the wedge base. To test this hypothesis we set up sandbox-type experiments where the backwall is not rigid but elastic. We vary stiffness, friction coefficients and amount of strain weakening during fault formation and reactivation within realistic ranges when scaled to nature and monitor backwall push force and surface deformation at high resolution. We observe slip instabilities both at seismic and accretionary cycle scale. Depending on the ratio of the amount of strain weakening to elastic stiffness, shortening rate increases transiently by a factor of 2-3 during fault growth. Applied to nature our observation suggests that episodic deformation transients might be interpreted as longterm slip instabilities related to crustal weakening at all relevant spatial scales: At local scale "slow earthquakes" might be interpreted as the result of the interplay between matrix stiffness and strain weakening in fault gouge material. At regional scale, applying buckling theory, we predict that deformation zones bordered by "soft" oceanic plates (e.g. the Andes) are more susceptible to deformation transients than "stiff" intracontinental settings (e.g. the Himalaya).

  1. Oasis: A high-level/high-performance open source Navier-Stokes solver

    NASA Astrophysics Data System (ADS)

    Mortensen, Mikael; Valen-Sendstad, Kristian

    2015-03-01

    Oasis is a high-level/high-performance finite element Navier-Stokes solver written from scratch in Python using building blocks from the FEniCS project (fenicsproject.org). The solver is unstructured and targets large-scale applications in complex geometries on massively parallel clusters. Oasis utilizes MPI and interfaces, through FEniCS, to the linear algebra backend PETSc. Oasis advocates a high-level, programmable user interface through the creation of highly flexible Python modules for new problems. Through the high-level Python interface the user is placed in complete control of every aspect of the solver. A version of the solver, that is using piecewise linear elements for both velocity and pressure, is shown to reproduce very well the classical, spectral, turbulent channel simulations of Moser et al. (1999). The computational speed is strongly dominated by the iterative solvers provided by the linear algebra backend, which is arguably the best performance any similar implicit solver using PETSc may hope for. Higher order accuracy is also demonstrated and new solvers may be easily added within the same framework.

  2. High Open-Circuit Voltage Solar Cells Based on Organic-Inorganic Lead Bromide Perovskite.

    PubMed

    Edri, Eran; Kirmayer, Saar; Cahen, David; Hodes, Gary

    2013-03-21

    Mesoscopic solar cells, based on solution-processed organic-inorganic perovskite absorbers, are a promising avenue for converting solar to electrical energy. We used solution-processed organic-inorganic lead halide perovskite absorbers, in conjunction with organic hole conductors, to form high voltage solar cells. There is a dire need for low-cost cells of this type, to drive electrochemical reactions or as the high photon energy cell in a system with spectral splitting. These perovskite materials, although spin-coated from solution, form highly crystalline materials. Their simple synthesis, along with high chemical versatility, allows tuning their electronic and optical properties. By judicious selection of the perovskite lead halide-based absorber, matching organic hole conductor, and contacts, a cell with a ∼ 1.3 V open circuit voltage was made. While further study is needed, this achievement provides a general guideline for additional improvement of cell performance.

  3. Ridges on Europa: Origin by Incremental Ice-Wedging

    NASA Technical Reports Server (NTRS)

    Melosh, H. J.; Turtle, E. P.

    2004-01-01

    The surface of Europa is covered by ridges that display a variety of morphologies . The most common type is characterized by a double ridge divided by an axial trough. These ridges are, in general, narrow (typically only a few km across) and remarkably linear. They are up to a few hundred meters high and the inner and outer slopes appear to stand at the angle of repose . A number of diverse mechanisms have been proposed to explain the formation of these ubiquitous features , although none can fully account for all of their observed characteristics. We propose a different formation theory in which accumulation of material within cracks that open during the extensional phase of the tidal cycle prevents complete closure of the cracks during the tidal cycle s compressional phase. This accumulation deforms the surrounding ice and, in time, results in the growth of a landform remarkably similar to the ridges observed on Europa.

  4. Nematic liquid crystal in the wedge and edge geometry in the case of homeotropic alignment.

    PubMed

    Poniewierski, A

    2010-02-01

    Nematic liquid crystal confined to a wedge or edge is studied on the assumption that the confining surfaces provide strong and weak homeotropic anchorings, respectively. Both infinite and finite systems are considered. The model based on the Frank-Oseen and Rapini-Papoular formalisms predicts two textures of opposite rotations of the director as in the case of strong anchoring on both surfaces. However, the presence of weak anchoring results in a length scale lambda which characterizes the crossover between the regions close to the apex and far from it. The ratio lambda/b , where b is the extrapolation length, is a function of the opening angle alpha. Both stable and metastable textures are considered and the mechanism by which a texture loses its stability is found. It is related to the formation of a defect-like structure at the surface of weak anchoring whose distance from the apex is lambda(alpha) and the loss of stability is signalled by the divergence of lambda. Only in the limit alpha --> 2tau, the defect-like structure transforms into a defect of strength -1/2 located at a finite distance from the apex. PMID:20195687

  5. Biomechanical effects of lateral and medial wedge insoles on unilateral weight bearing

    PubMed Central

    Sawada, Tomonori; Kito, Nobuhiro; Yukimune, Masaki; Tokuda, Kazuki; Tanimoto, Kenji; Anan, Masaya; Takahashi, Makoto; Shinkoda, Koichi

    2016-01-01

    [Purpose] Lateral wedge insoles reduce the peak external knee adduction moment and are advocated for patients with knee osteoarthritis. However, some patients demonstrate adverse biomechanical effects with treatment. In this study, we examined the immediate effects of lateral and medial wedge insoles under unilateral weight bearing. [Subjects and Methods] Thirty healthy young adults participated in this study. The subjects were assessed by using the foot posture index, and were divided into three groups: normal foot, pronated foot, and supinated foot groups. The knee adduction moment and knee-ground reaction force lever arm under the studied conditions were measured by using a three-dimensional motion capture system and force plates. [Results] In the normal and pronated groups, the change in knee adduction moment significantly decreased under the lateral wedge insole condition compared with the medial wedge insole condition. In the normal group, the change in the knee-ground reaction force lever arm also significantly decreased under the lateral wedge insole condition than under the medial wedge insole condition. [Conclusion] Lateral wedge insoles significantly reduced the knee adduction moment and knee-ground reaction force lever arm during unilateral weight bearing in subjects with normal feet, and the biomechanical effects varied according to individual foot alignment. PMID:26957775

  6. Biomechanical effects of lateral and medial wedge insoles on unilateral weight bearing.

    PubMed

    Sawada, Tomonori; Kito, Nobuhiro; Yukimune, Masaki; Tokuda, Kazuki; Tanimoto, Kenji; Anan, Masaya; Takahashi, Makoto; Shinkoda, Koichi

    2016-01-01

    [Purpose] Lateral wedge insoles reduce the peak external knee adduction moment and are advocated for patients with knee osteoarthritis. However, some patients demonstrate adverse biomechanical effects with treatment. In this study, we examined the immediate effects of lateral and medial wedge insoles under unilateral weight bearing. [Subjects and Methods] Thirty healthy young adults participated in this study. The subjects were assessed by using the foot posture index, and were divided into three groups: normal foot, pronated foot, and supinated foot groups. The knee adduction moment and knee-ground reaction force lever arm under the studied conditions were measured by using a three-dimensional motion capture system and force plates. [Results] In the normal and pronated groups, the change in knee adduction moment significantly decreased under the lateral wedge insole condition compared with the medial wedge insole condition. In the normal group, the change in the knee-ground reaction force lever arm also significantly decreased under the lateral wedge insole condition than under the medial wedge insole condition. [Conclusion] Lateral wedge insoles significantly reduced the knee adduction moment and knee-ground reaction force lever arm during unilateral weight bearing in subjects with normal feet, and the biomechanical effects varied according to individual foot alignment.

  7. Inferring the spatial variation of the wedge strength based on a modified critical taper model

    NASA Astrophysics Data System (ADS)

    Yang, C.; Liu, H.; Hsieh, Y.; Dong, J.

    2013-12-01

    Critical taper wedge theory has been widely applied to evaluate the strength of the detachment fault and the wedge by measuring taper angle. Traditional taper model, which incorporated constant cohesion and friction angle, fails to explain the lateral variation of the taper angle. A modified critical taper model adopting nonlinear Hoek-Brown failure criterion is proposed accordingly. The fold-and-thrust belt of central Taiwan was studied. Based on the field works and laboratory tests, the geological strength index (GSI) and the uniaxial compressive strength were obtained and the wedge strength can be estimated accordingly. The GSI values from investigation are decreased from the west to the east along the cross section due to the wedge strength heterogeneity. The uniaxial compressive strength of intact rock varies from the age of formation and lithology. The estimated wedge strength exhibits a strong spatial variation. The strength of the detachment fault was derived from rotary shear tests using fault gouge materials under different velocities and normal stresses. General speaking, the steady-state friction coefficient are about 0.29-0.46 when the shear velocity less than 0.1 m/s. The friction coefficient is not sensitive to the normal stress. Consequently, the lateral variation of the taper angle, which calculated by modified critical taper model, is mainly dominated by the wedge strength heterogeneity and the thickening of the wedge from the west to the east.

  8. Gap Test Modeling to Predict Wedge Tests Initiation of PBXN-103

    NASA Astrophysics Data System (ADS)

    Richmond, Clinton Thomas

    1997-07-01

    The experimental Initiation of PBXN-103 by the standard wedge test has been modeled by using the HVRB initiation and growth model in the CTH code. The P-081 plane wave lens was used as initiator in these experiments. The wedge test was converted to a gap test by replacing the PBXN-103 wedge by a PBXN-103 cylinder. By modeling this gap test, shock initiation in the PBXN-103 was calculated. The results of these calculations are in agreement with the experimental results of the wedge tests. Comparison of the CTH code calculations with the wedge test data was accomplished by using an auxiliary program to the CTH code called the BCAT code. In particular, it computes the ``pop plot'' and compares it to the wedge test data. It also predicts other fundamental results of the wedge test. Shock initiation of PBX-9404 was also calculated by the HVRB model and compared to the same calculation using the Lee-Tarver model. Comparison of the two calculations indicate that the HVRB model is apparently as good as the Lee-Tarver model.

  9. Diffuse holographic interferometric observation of shock wave reflection from a skewed wedge

    NASA Astrophysics Data System (ADS)

    Numata, D.; Ohtani, K.; Takayama, K.

    2009-06-01

    The pattern of shock wave reflection over a wedge is, in general, either a regular reflection or a Mach reflection, depending on wedge angles, shock wave Mach numbers, and specific heat ratios of gases. However, regular and Mach reflections can coexist, in particular, over a three-dimensional wedge surface, whose inclination angles locally vary normal to the direction of shock propagation. This paper reports a result of diffuse double exposure holographic interferometric observations of shock wave reflections over a skewed wedge surface placed in a 100 × 180 mm shock tube. The wedge consists of a straight generating line whose local inclination angle varies continuously from 30° to 60°. Painting its surface with fluorescent spray paint and irradiating its surface with a collimated object beam at a time interval of a few microseconds, we succeeded in visualizing three-dimensional shock reflection over the skewed wedge surface. Experiments were performed at shock Mach numbers, 1.55, 2.02, and 2.53 in air. From reconstructed holographic images, we estimated critical transition angles at these shock wave Mach numbers and found that these were very close to those over straight wedges. This is attributable to the flow three-dimensionality.

  10. Spatially Concentrated Erosion Focuses Deformation Within the Himalayan Orogenic Wedge: Sutlej Valley, NW Himalaya, India

    NASA Astrophysics Data System (ADS)

    Thiede, R. C.; Arrowsmith, J.; Bookhagen, B.; McWilliams, M.; Sobel, E. R.; Strecker, M. R.

    2004-12-01

    Long-term erosion processes in the NW-Himalaya have not only shaped the distribution of topography and relief, but may also exert a regional control on the kinematic history of the Himalayan orogenic wedge. The topographic front of the orogenic wedge forms the southern margin of the High Himalaya and may be related to subsurface structures such as a crustal ramp or a blind thrust. Drastic along- and across-strike erosional gradients characterize the modern Himalaya and range from high-erosion regions along the southern High Himalayan front where monsoonal precipitation is able to penetrate far into the range, to low-erosion sectors across the moderately elevated Lesser Himalaya to the south and the high-elevation, arid sectors to the north. Published paleo-elevation estimates from the Thakkhola Graben (Nepal) suggest that by ~11 Ma the southern Tibetan Plateau and probably the High Himalaya had been uplifted to elevations comparable to the recent conditions. Thus, the presently observed pronounced erosional gradients have likely existed across the orogen since then. However, the cause of high rock-uplift and exhumation rates along distinct segments of the southern front of the High Himalaya are still a matter of debate. New apatite fission track (AFT) and 40Ar/39Ar data sampled along an orogen-perpendicular transect following the Sutlej Valley, approximately perpendicular to the Himalayan orogen, constrain the distribution patterns of rapid cooling related to rock uplift and exhumation. Combined with published thermochronologic data, this comprehensive AFT dataset from south of the High Himalaya mountain front to the interior of the Tethyan Himalaya allows us to derive a regional uplift and exhumation scenario. Our new 40Ar/39Ar ages ranging between 17 and 4 Ma reveal diachronous exhumation of two crystalline nappes (Higher and Lesser Himalayan crystalline) during Miocene-Pliocene time. In contrast, the AFT data ranging from 1.3 to 4.6 Ma indicate synchronous, fast

  11. OpenCL: a viable solution for high-performance medical image reconstruction?

    NASA Astrophysics Data System (ADS)

    Siegl, Christian; Hofmann, H. G.; Keck, B.; Prümmer, M.; Hornegger, J.

    2011-03-01

    Reconstruction of 3-D volumetric data from C-arm CT projections is a computationally demanding task. For interventional image reconstruction, hardware optimization is mandatory. Manufacturers of medical equipment use a variety of high-performance computing (HPC) platforms, like FPGAs, graphics cards, or multi-core CPUs. A problem of this diversity is that many different frameworks and (vendor-specific) programming languages are used. Furthermore, it is costly to switch the platform, since the code has to be re-written, verified, and optimized. OpenCL, a relatively new industry standard for HPC, promises to enable portable code. Its key idea is to abstract hardware in a way that allows an efficient mapping onto real CPUs, GPUs, and other hardware. The code is compiled for the actual target by the device driver. In this work we investigated the suitability of OpenCL as a tool to write portable code that runs efficiently across different hardware. The problems chosen are back- and forward-projection, the most time-consuming parts of (iterative) reconstruction. We present results on three platforms, a multi-core CPU system and two GPUs, and compare them against manually optimized native implementations. We found that OpenCL allows to share a common framework in one language across platforms. However, considering differences in the underlying architecture, a hardware-oblivious implementation cannot be expected to deliver maximal performance. By optimizing the OpenCL code for the specific hardware we reached over 90% of native performance for both problems, back- and forward-projection, on all platforms.

  12. Metastable olivine wedge beneath northeast China and its applications

    NASA Astrophysics Data System (ADS)

    Jiang, G.; Zhao, D.; Zhang, G.

    2013-12-01

    When the Pacific slab subducted into the mantle transition zone, there might exist a metastable olivine wedge (MOW) inside the slab due to the phase transition. Lots of researchers have adopted such various methods to detect the characteristics of this MOW as the forward modeling of travel times, shear wave amplitude patterns, teleseismic P wave coda, receiver function imaging, thermodynamic simulation and so on. Almost all results could be more or less affected by the source, the receiver and/or the velocity model passed through by the seismic rays. In this study, we have used 21 deep earthquakes, greater than 400 km and locating beneath northeast China, to study the velocity within the MOW. For more precisions, we have done further modifications in two ways based on our previous studies. (1) Double-difference location method is used to relocate all events with an error of 1-2 km with the data recorded by stations both at northeast China and at Japan. All relocated events locate in a zone about 30 km away from the upper boundary of Pacific slab. (2) Double residual travel times, generated by an event-pair at a common station at only Japan, are used to constrain the velocity anomaly rather than the residuals themselves. As a result, we have found that an ultra-lower velocity zone (ULVZ), averagely -7% relative to the iasp91 model, exists within the subducted Pacific slab around the deep earthquakes, which might be represented as the metastable olivine wedge. Because of the lower-velocity corresponding to the lower-density, the MOW would provide upward buoyancy forces which might prevent the slab from free subduction into the mantle transition zone. This feed-back mechanism of MOW to the slab is called ';parachute-effect', which is characterized by other researchers. In addition, the existence of the ULVZ or the MOW in the slab may supply a possible mechanism for triggering deep earthquakes, called ';phase transformation faulting', which was already proposed few

  13. Application of the critical Coulomb wedge theory to hyper-extended, magma-poor rifted margins

    NASA Astrophysics Data System (ADS)

    Nirrengarten, M.; Manatschal, G.; Yuan, X. P.; Kusznir, N. J.; Maillot, B.

    2016-05-01

    The Critical Coulomb Wedge Theory (CCWT) has been extensively used in compressional tectonics to resolve the shape of orogenic or accretionary prisms, while it is less applied to extensional and gravitational wedges despite the fact that it can be described by the same equation. In particular, the hyper-extended domain at magma-poor rifted margins, forming the oceanward termination of extended continental crust, satisfies the three main requirements of the CCWT: 1) it presents a wedge shape, 2) the rocks forming the wedge are completely brittle (frictional), and 3) the base of the wedge corresponds to a low friction décollement. However hyper-extended margins present a fully frictional behaviour only for a very thin crust; therefore this study is limited to the termination of hyper-extended continental crust which deforms in the latest stage of continental rifting. In this paper we define a method to measure the surface slope and the basal deep of this wedge that we apply to 17 hyper-extended, magma-poor rifted margins in order to compare the results to the values predicted by the CCWT. Because conjugate pairs of hyper-extended, magma-poor rifted margins are commonly asymmetric, due to detachment faulting, the wedges in the upper and lower plate margins corresponding respectively to the hanging wall and footwall of the detachment system are different. While the stress field in the upper plate wedge corresponds to a tectonic extensional wedge, the one in the lower plate matches that of a gravity extensional wedge. Using typical frictional properties of phyllosilicates (e.g. clays and serpentine), the shape of the hyper-extended wedges can be resolved by the CCWT using consistent fluid overpressures. Our results show that all lower plate margins are gravitationally stable and therefore have a close to critical shape whereas the tectonic extensional wedges at upper plate margins are critical, sub or sup critical due to the detachment initial angle and the duration of

  14. Line-shape flattening resulting from hypersonic nozzle wedge flow in low-pressure chemical lasers.

    PubMed

    Livingston, P M; Bullock, D L

    1980-07-01

    The new hypersonic wedge nozzle (HYWN) supersonic wedge nozzle design produces a significant component of directed gas flow along the optical axis of a laser cavity comparable to thermal speeds. The gain-line-shape function is broadened and the refractive-index line shape is also spread as a function of wedge-flow half-angle. An analytical treatment as well as a numerical study is presented that evaluates the Doppler-directed-flow impact on the number of longitudinal modes and their frequencies as well as on gain and refractive-index saturation of those that lase in a Fabry-Perot cavity.

  15. High-Throughput Metagenomic Technologies for Complex Microbial Community Analysis: Open and Closed Formats

    PubMed Central

    He, Zhili; Yang, Yunfeng; Deng, Ye; Tringe, Susannah G.; Alvarez-Cohen, Lisa

    2015-01-01

    ABSTRACT   Understanding the structure, functions, activities and dynamics of microbial communities in natural environments is one of the grand challenges of 21st century science. To address this challenge, over the past decade, numerous technologies have been developed for interrogating microbial communities, of which some are amenable to exploratory work (e.g., high-throughput sequencing and phenotypic screening) and others depend on reference genes or genomes (e.g., phylogenetic and functional gene arrays). Here, we provide a critical review and synthesis of the most commonly applied “open-format” and “closed-format” detection technologies. We discuss their characteristics, advantages, and disadvantages within the context of environmental applications and focus on analysis of complex microbial systems, such as those in soils, in which diversity is high and reference genomes are few. In addition, we discuss crucial issues and considerations associated with applying complementary high-throughput molecular technologies to address important ecological questions. PMID:25626903

  16. High-throughput metagenomic technologies for complex microbial community analysis. Open and closed formats

    SciTech Connect

    Zhou, Jizhong; He, Zhili; Yang, Yunfeng; Deng, Ye; Tringe, Susannah G.; Alvarez-Cohen, Lisa

    2015-01-27

    Understanding the structure, functions, activities and dynamics of microbial communities in natural environments is one of the grand challenges of 21st century science. To address this challenge, over the past decade, numerous technologies have been developed for interrogating microbial communities, of which some are amenable to exploratory work (e.g., high-throughput sequencing and phenotypic screening) and others depend on reference genes or genomes (e.g., phylogenetic and functional gene arrays). Here, we provide a critical review and synthesis of the most commonly applied “open-format” and “closed-format” detection technologies. We discuss their characteristics, advantages, and disadvantages within the context of environmental applications and focus on analysis of complex microbial systems, such as those in soils, in which diversity is high and reference genomes are few. In addition, we discuss crucial issues and considerations associated with applying complementary high-throughput molecular technologies to address important ecological questions.

  17. High-throughput metagenomic technologies for complex microbial community analysis: open and closed formats.

    PubMed

    Zhou, Jizhong; He, Zhili; Yang, Yunfeng; Deng, Ye; Tringe, Susannah G; Alvarez-Cohen, Lisa

    2015-01-27

    Understanding the structure, functions, activities and dynamics of microbial communities in natural environments is one of the grand challenges of 21st century science. To address this challenge, over the past decade, numerous technologies have been developed for interrogating microbial communities, of which some are amenable to exploratory work (e.g., high-throughput sequencing and phenotypic screening) and others depend on reference genes or genomes (e.g., phylogenetic and functional gene arrays). Here, we provide a critical review and synthesis of the most commonly applied "open-format" and "closed-format" detection technologies. We discuss their characteristics, advantages, and disadvantages within the context of environmental applications and focus on analysis of complex microbial systems, such as those in soils, in which diversity is high and reference genomes are few. In addition, we discuss crucial issues and considerations associated with applying complementary high-throughput molecular technologies to address important ecological questions.

  18. Decarbonation and carbonation processes in the slab and mantle wedge - insights from thermomechanical modeling

    NASA Astrophysics Data System (ADS)

    Gonzalez, C. M.; Gorczyk, W.; Connolly, J. A.; Gerya, T.; Hobbs, B. E.; Ord, A.

    2013-12-01

    Subduction zones offer one of the most geologically active and complex systems to investigate. They initiate a process in which crustal sediments are recycled, mantle heterogeneities arise, and mantle wedge refertilization occurs via slab derived volatiles and magma generation. Slab derived volatiles, consisting primarily of H2O - CO2 fluids, are especially critical in subduction evolution as they rheologically weaken the mantle wedge, decrease solidus temperatures, and rock-fluid interactions result in metasomatism. While the effects of H2O in these processes have been well studied in the past decades, CO2's role remains open for much scientific study. This is partly attributed to the sensitivity of decarbonation to the thermal gradient of the subduction zone, bulk compositions (sediments, basalts, peridotites) and redox state of the mantle. Here we show benchmarking results of a subduction scenario that implements carbonation-decarbonation reactions into a fully coupled petrological-thermomechanical numerical modeling code. We resolve stable mineralogy and extract rock properties via Perple_X at a resolution of 5°C and 25 MPa. The numerical technique employed is a characteristics-based marker-in-cell technique with conservative finite-differences that includes visco-elastic-plastic rheologies (I2ELVIS). The devolatilized fluids are tracked via markers that are either generated or consumed based on P-T conditions. The fluids are also allowed to freely advect within the velocity field. The hosts for CO2 in this system are computed via GLOSS average sediments (H2O: 7.29 wt% & CO2: 3.01 wt%), metabasalts ( H2O: 2.63 & CO2: 2.90 wt%), and ophicarbonates (H2O: 1.98 wt% & CO2: 5.00 wt%). Our results demonstrate the feasibility of applying this decarbonation-carbonation numerical method to a range of geodynamic scenarios that simulate the removal of CO2 from the subducting slab. Such applicable scenarios include sediment diapirism into the convecting wedge and better

  19. Motion control of the wedge prisms in Risley-prism-based beam steering system for precise target tracking.

    PubMed

    Zhou, Yuan; Lu, Yafei; Hei, Mo; Liu, Guangcan; Fan, Dapeng

    2013-04-20

    Two exact inverse solutions of Risley prisms have been given by previous authors, based on which we calculate the gradients of the scan field that open a way to investigate the nonlinear relationship between the slewing rate of the beam and the required angular velocities of the two wedge prisms in the Risley-prism-based beam steering system for target tracking. The limited regions and singularity point at the center and the edge of the field of regard are discussed. It is found that the maximum required rotational velocities of the two prisms for target tracking are nearly the same and are dependent on the altitude angle. The central limited region is almost independent of the prism parameters. The control singularity at the crossing center path can be avoided by switching the two solutions.

  20. High school students' enactment of chemistry knowing in open-entry laboratory investigations

    NASA Astrophysics Data System (ADS)

    Pilane, Sentsetsa M.

    2003-10-01

    This study is an exploration of student meaning making in a non-traditional, high activity, hands-on grade 12 high school chemistry setting. The study focused on a sequence of three "open-entry" laboratory investigations (i.e., iodine clock reaction, pop-can cell and electroplating). These open-entry laboratory investigations were designed to be flexible and to take place in settings where students could make an impact. Students were responsible for devising their own problem and entry strategy, for making decisions about what reagents to use, what variables to manipulate, and how to proceed to develop the problem to a resolution acceptable to them and to the teacher. To explore students' meaning making in open-entry laboratory settings, their interactions were video taped and samples of their written laboratory reports were collected from time to time. Students were also requested to write reflective notes on their experiences of each investigation, some students were interviewed at the end of the course. This thesis consists of accounts and interpretations of what students did and said as they made meaning in these open-entry, hands-on laboratory investigations. The research uses an enactivist perspective to explore the meanings emerging from the study. From an enactivist view, cognition is seen as perceptually guided action in which a knower brings forth a world of significance with others. Enactivism suggests that students do not only express their knowing in what they say or write but also in their actions with others within this learning community. The research revealed that meaning making in these circumstances was highly complex. It involved systematic trial and error at various levels within the multiple iterative feedback loops. Students' interactions in this setting were mediated by the culture of chemistry which is embodied in the practices of the discipline. With students having to make decisions with every action, their meaning making was not only

  1. Dose distribution analysis of physical and dynamic wedges by using an intensity-modulated radiotherapy MatriXX

    NASA Astrophysics Data System (ADS)

    Lee, Hae-Kag; Cho, Jae-Hwan; Cho, Dae-chul

    2013-05-01

    This study investigated differences between the physical wedge and the dynamic wedge distributions of radiation by using an intensity-modulated radiotherapy (ImRT) MatriXX. The linear accelerator used X-rays with energy levels of 6 MV and 10 MV to adjust the collimator by motoring the independent jaws (X1, X2, Y1, Y2) for setting wedge angles of 15, 30, 45, and 60 degrees. The collimator field size was set as 10 × 10 cm2 or 20 × 20 cm2 at the maximum dose point. The dose distribution for each wedge had ±5% and ±11% errors for field sizes of 10 × 10 cm2 and 20 × 20 cm2, respectively. The error was greatest at a wedge angle of 45 degrees and was pronounced at the end of the dynamic wedge where Y1 and Y2 met. Consequently, concluded that the dose distributions were similar for both wedges for the field size of a small beam profile. The beam dose was greatly increased at the end of the dynamic wedge. A more precise estimate of the therapeutic dose of radiation for a dynamic wedge that nearly matches that of the physical wedge can be achieved by correcting of the increasing part of the beam dose. The findings imply that a heavy wedge filter should not be used when calculating the isodose distribution and the therapeutic dose.

  2. The role of pore fluid overpressure in the substrates of advancing salt sheets, ice glaciers, and critical-state wedges

    NASA Astrophysics Data System (ADS)

    Luo, Gang; Flemings, Peter B.; Hudec, Michael R.; Nikolinakou, Maria A.

    2015-01-01

    Critical-state wedges, ice glaciers, and salt sheets have many geometric and mechanical similarities. Each has a tapering geometry and moves along a basal detachment. Their motions result from the combined effects of internal deformation and basal sliding. Wedge deformation and geometry, basal conditions, and overpressure (pore fluid pressure less hydrostatic pore fluid pressure) development within the substrate interact with each other in this mechanically coupled system. However, the nature of this interaction is poorly understood. In order to investigate this coupled system, we have developed two-dimensional poromechanical finite-element models with porous fluid flow in sediments. We have simulated the advance of a salt sheet wedge across poroelastic sediments in this study. We emphasize that our results have applications beyond salt wedges to both critical-state wedges and ice glaciers. Overpressure develops within the substrate over time during the advance of the wedge. The magnitude of the overpressure influences the wedge geometry and the wedge advance rate. Lower overpressure results in a thicker and steeper wedge geometry, and a slower advance rate, while higher overpressure favors a thinner, wider, and more flattened wedge geometry and a faster advance rate. This study provides key insights into the links between wedge geometry, basal shear stress, and overpressure in substrates.

  3. Influence of intermolecular forces at critical-point wedge filling.

    PubMed

    Malijevský, Alexandr; Parry, Andrew O

    2016-04-01

    We use microscopic density functional theory to study filling transitions in systems with long-ranged wall-fluid and short-ranged fluid-fluid forces occurring in a right-angle wedge. By changing the strength of the wall-fluid interaction we can induce both wetting and filling transitions over a wide range of temperatures and study the order of these transitions. At low temperatures we find that both wetting and filling transitions are first order in keeping with predictions of simple local effective Hamiltonian models. However close to the bulk critical point the filling transition is observed to be continuous even though the wetting transition remains first order and the wetting binding potential still exhibits a small activation barrier. The critical singularities for adsorption for the continuous filling transitions depend on whether retarded or nonretarded wall-fluid forces are present and are in excellent agreement with predictions of effective Hamiltonian theory even though the change in the order of the transition was not anticipated.

  4. Transonic flow past a wedge profile with detached bow wave

    NASA Technical Reports Server (NTRS)

    Vincenti, Walter G; Wagoner, Cleo B

    1952-01-01

    A theoretical study has been made of the aerodynamic characteristics at zero angle of attack of a thin, doubly symmetrical double-wedge profile in the range of supersonic flight speed in which the bow wave is detached. The analysis utilizes the equations of the transonic small-disturbance theory and involves no assumptions beyond those implicit in this theory. The mixed flow about the front half of the profile is calculated by relaxation solution of boundary conditions along the shock polar and sonic line. The purely subsonic flow about the rear of the profile is found by means of the method of characteristics specialized to the transonic small-disturbance theory. Complete calculations were made for four values of the transonic similarity parameter. These were found sufficient to bridge the gap between the previous results of Guderley and Yoshihara at a Mach number of 1 and the results which are readily obtained when the bow wave is attached and the flow is completely supersonic.

  5. Hydrodynamics of superfluids confined in blocked rings and wedges.

    PubMed

    Dasgupta, Chandan; Valls, Oriol T

    2009-01-01

    Motivated by many recent experimental studies of nonclassical rotational inertia (NCRI) in superfluid and supersolid samples, we present a study of the hydrodynamics of a superfluid confined in the two-dimensional region (equivalent to a long cylinder) between two concentric arcs of radii b and a (bwedges (b=0) with beta>pi , we find an unexpected divergence of the velocity at the origin, which implies the presence of either a region of normal fluid or a vortex for any nonzero value of the angular velocity. Implications of our results for experiments on "supersolid" behavior in solid 4He are discussed. A number of mathematical issues are pointed out and resolved. PMID:19257135

  6. Performance of an isolated two-dimensional variable-geometry wedge nozzle with translating shroud and collapsing wedge at speeds up to Mach 2.01

    NASA Technical Reports Server (NTRS)

    Maiden, D. L.

    1975-01-01

    A wind-tunnel investigation was conducted to determine the aeropropulsion performance (thrust-minus-drag) of a single-engine, variable-geometry, two-dimensional (2-D) wedge nozzle with simulated translating-shroud and collapsing-wedge mechanisms. The investigation was conducted statically and at Mach numbers from 0.60 to 2.01 at an angle of attack of 0 deg and at varied jet total-pressure ratios up to 21, depending on the Mach number. The results indicate that the isolated aeropropulsion performance of a variable-geometry two-dimensional wedge nozzle is competitive with axisymmetric nozzles at transonic and supersonic speeds, but the isolated performance is slightly inferior for static take-off and low subsonic speeds. With the use of a simple tertiary-air ejector, the static take-off performance was increased.

  7. Clinical implementation of enhanced dynamic wedges into the Pinnacle treatment planning system: Monte Carlo validation and patient-specific QA

    NASA Astrophysics Data System (ADS)

    Ahmad, Munir; Deng, Jun; Lund, Molly W.; Chen, Zhe; Kimmett, James; Moran, Meena S.; Nath, Ravinder

    2009-01-01

    The goal of this work is to present a systematic Monte Carlo validation study on the clinical implementation of the enhanced dynamic wedges (EDWs) into the Pinnacle3 (Philips Medical Systems, Fitchburg, WI) treatment planning system (TPS) and QA procedures for patient plan verification treated with EDWs. Modeling of EDW beams in the Pinnacle3 TPS, which employs a collapsed-cone convolution superposition (CCCS) dose model, was based on a combination of measured open-beam data and the 'Golden Segmented Treatment Table' (GSTT) provided by Varian for each photon beam energy. To validate EDW models, dose profiles of 6 and 10 MV photon beams from a Clinac 2100 C/D were measured in virtual water at depths from near-surface to 30 cm for a wide range of field sizes and wedge angles using the Profiler 2 (Sun Nuclear Corporation, Melbourne, FL) diode array system. The EDW output factors (EDWOFs) for square fields from 4 to 20 cm wide were measured in virtual water using a small-volume Farmer-type ionization chamber placed at a depth of 10 cm on the central axis. Furthermore, the 6 and 10 MV photon beams emerging from the treatment head of Clinac 2100 C/D were fully modeled and the central-axis depth doses, the off-axis dose profiles and the output factors in water for open and dynamically wedged fields were calculated using the Monte Carlo (MC) package EGS4. Our results have shown that (1) both the central-axis depth doses and the off-axis dose profiles of various EDWs computed with the CCCS dose model and MC simulations showed good agreement with the measurements to within 2%/2 mm; (2) measured EDWOFs used for monitor-unit calculation in Pinnacle3 TPS agreed well with the CCCS and MC predictions within 2%; (3) all the EDW fields satisfied our validation criteria of 1% relative dose difference and 2 mm distance-to-agreement (DTA) with 99-100% passing rate in routine patient treatment plan verification using MapCheck 2D diode array.

  8. Evaluation of ‘OpenCL for FPGA’ for Data Acquisition and Acceleration in High Energy Physics

    NASA Astrophysics Data System (ADS)

    Sridharan, Srikanth

    2015-12-01

    The increase in the data acquisition and processing needs of High Energy Physics experiments has made it more essential to use FPGAs to meet those needs. However harnessing the capabilities of the FPGAs has been hard for anyone but expert FPGA developers. The arrival of OpenCL with the two major FPGA vendors supporting it, offers an easy software-based approach to taking advantage of FPGAs in applications such as High Energy Physics. OpenCL is a language for using heterogeneous architectures in order to accelerate applications. However, FPGAs are capable of far more than acceleration, hence it is interesting to explore if OpenCL can be used to take advantage of FPGAs for more generic applications. To answer these questions, especially in the context of High Energy Physics, two applications, a DAQ module and an acceleration workload, were tested for implementation with OpenCL on FPGAs2. The challenges on using OpenCL for a DAQ application and their solutions, together with the performance of the OpenCL based acceleration are discussed. Many of the design elements needed to realize a DAQ system in OpenCL already exists, mostly as FPGA vendor extensions, but a small number of elements were found to be missing. For acceleration of OpenCL applications, using FPGAs has become as easy as using GPUs. OpenCL has the potential for a massive gain in productivity and ease of use enabling non FPGA experts to design, debug and maintain the code. Also, FPGA power consumption is much lower than other implementations. This paper describes one of the first attempts to explore the use of OpenCL for applications outside the acceleration workloads.

  9. Deformation in the mantle wedge associated with Laramide flat-slab subduction

    NASA Astrophysics Data System (ADS)

    Behr, Whitney M.; Smith, Douglas

    2016-07-01

    Laramide crustal deformation in the Rocky Mountains of the west-central United States is often considered to relate to a narrow segment of shallow subduction of the Farallon slab, but there is no consensus as to how deformation along the slab-mantle lithosphere interface was accommodated. Here we investigate deformation in mantle rocks associated with hydration and shear above the flat-slab at its contact with the base of the North American plate. The rocks we focus on are deformed, hydrated, ultramafic inclusions hosted within diatremes of the Navajo Volcanic Field in the central Colorado Plateau that erupted during the waning stages of the Laramide orogeny. We document a range of deformation textures, including granular peridotites, porphyroclastic peridotites, mylonites, and cataclasites, which we interpret to reflect different proximities to a slab-mantle-interface shear zone. Mineral assemblages and chemistries constrain deformation to hydrous conditions in the temperature range ˜550-750°C. Despite the presence of hydrous phyllosilicates in modal percentages of up to 30%, deformation was dominated by dislocation creep in olivine. The mylonites exhibit an uncommon lattice preferred orientation (LPO) in olivine, known as B-type LPO in which the a-axes are aligned perpendicular to the flow direction. The low temperature, hydrated setting in which these fabrics formed is consistent with laboratory experiments that indicate B-type LPOs form under conditions of high stress and high water contents; furthermore, the mantle wedge context of these LPOs is consistent with observations of trench-parallel anisotropy in the mantle wedge above many modern subduction zones. Differential stress magnitudes in the mylonitic rocks estimated using paleopiezometry range from 290 to 444 MPa, and calculated effective viscosities using a wet olivine flow law are on the order of 1019-1023 Pa s. The high stress magnitudes, high effective viscosities, and high strains recorded in these

  10. Measurements of dose from secondary radiation outside a treatment field: effects of wedges and blocks

    SciTech Connect

    Sherazi, S.; Kase, K.R.

    1985-12-01

    Radiation dose outside the radiotherapy treatment field can be significant and therefore is of clinical interest in estimating organ doses. In a previous paper we reported the results of measurements made using unmodified radiation fields. We have extended this study to include the effects of wedge filters and blocks. For a given dose on the central axis of a radiation field, wedges can cause a factor of 2 to 4 increase in dose at any point outside the field compared with the dose when no wedge is used. Adding blocks to a treatment field can cause an increase in dose at points outside the field, but the effect is much smaller than the effect of a wedge, and generally less than a factor of 2. From the results of these measurements, doses to selected organs outside the field for specified treatment geometries were estimated, and the potential for reducing these organ doses by additional shielding was assessed.

  11. Study on Mach stems induced by interaction of planar shock waves on two intersecting wedges

    NASA Astrophysics Data System (ADS)

    Xiang, Gaoxiang; Wang, Chun; Teng, Honghui; Yang, Yang; Jiang, Zonglin

    2016-06-01

    The properties of Mach stems in hypersonic corner flow induced by Mach interaction over 3D intersecting wedges were studied theoretically and numerically. A new method called "spatial dimension reduction" was used to analyze theoretically the location and Mach number behind Mach stems. By using this approach, the problem of 3D steady shock/shock interaction over 3D intersecting wedges was transformed into a 2D moving one on cross sections, which can be solved by shock-polar theory and shock dynamics theory. The properties of Mach interaction over 3D intersecting wedges can be analyzed with the new method, including pressure, temperature, density in the vicinity of triple points, location, and Mach number behind Mach stems. Theoretical results were compared with numerical results, and good agreement was obtained. Also, the influence of Mach number and wedge angle on the properties of a 3D Mach stem was studied.

  12. Plane-wave diffraction by a wedge: A spectral domain approach

    NASA Astrophysics Data System (ADS)

    Ciarkowski, A.; Mittra, R.

    1981-11-01

    In this paper we investigate the canonical problem of plane wave diffraction by a wedge in the context of the spectral domain approach which exploits the relationship between the induced current on a scatterer and its far field. We show how the Sommerfeld solution to the wedge diffraction problem can be manipulated in a form which enables one to interpret the far scattered field as the Fourier transform of the physical optics current on the two faces of the wedge, augmented by the fringe current near the tip of the wedge. We also show that the uniform asymptotic expansion derived by Lee and Deschamps on the basis of the Lewis, Ahluwalia and Boersma ansatz can be rigorously obtained using the approach presented in this paper.

  13. Plane-wave diffraction by a wedge - A spectral domain approach

    NASA Astrophysics Data System (ADS)

    Ciarkowski, A.; Boersma, J.; Mittra, R.

    1984-01-01

    The canonical problem of plane wave diffraction by a wedge in the context of the spectral domain approach which exploits the relationship between the induced current on a scatterer and its far field is investigated. It is shown how the exact solution to the wedge diffraction problem can be manipulated in a form which enables one to interpret the far scattered field as the Fourier transform of the physical optics (PO) current on the two faces of the wedge augmented by the fringe current near the tip of the wedge. A uniform asymptotic expansion for the total field which slightly modifies the Ansatz in the uniform asymptotic theory of electromagnetic edge diffraction is constructed.

  14. Open and closed shear-walls in high-rise structural systems: Static and dynamic analysis

    NASA Astrophysics Data System (ADS)

    Carpinteri, Alberto; Lacidogna, Giuseppe; Nitti, Giuseppe

    2016-06-01

    In the present paper, a General Algorithm is applied to the analysis of high-rise structures. This algorithm is to be used as a calculation tool in preliminary design; it allows to define the interaction between closed and open, straight or curved shear-walls, and the forces exchanged in structures subject to mainly horizontal loads. The analysis can be performed in both static and dynamic regimes, the mode shapes and the natural frequencies being assessed. This general formulation allows analyses of high-rise structures by taking into account the torsional rigidity and the warping deformations of the elements composing the building without gross simplifications. In thisway it is possible to model the structure as a single equivalent cantilever, thus minimising the degrees of freedom of the system, and consequently the calculation time. Finally, potentials of the method proposed are demonstrated by a numerical example which emphasizes the link between global displacements and stresses in the elements composing the structure.

  15. kspectrum: an open-source code for high-resolution molecular absorption spectra production

    NASA Astrophysics Data System (ADS)

    Eymet, V.; Coustet, C.; Piaud, B.

    2016-01-01

    We present the kspectrum, scientific code that produces high-resolution synthetic absorption spectra from public molecular transition parameters databases. This code was originally required by the atmospheric and astrophysics communities, and its evolution is now driven by new scientific projects among the user community. Since it was designed without any optimization that would be specific to any particular application field, its use could also be extended to other domains. kspectrum produces spectral data that can subsequently be used either for high-resolution radiative transfer simulations, or for producing statistic spectral model parameters using additional tools. This is a open project that aims at providing an up-to-date tool that takes advantage of modern computational hardware and recent parallelization libraries. It is currently provided by Méso-Star (http://www.meso-star.com) under the CeCILL license, and benefits from regular updates and improvements.

  16. Salt-wedge propagation in a Mediterranean micro-tidal river mouth

    NASA Astrophysics Data System (ADS)

    Haralambidou, Kiriaki; Sylaios, Georgios; Tsihrintzis, Vassilios A.

    2010-12-01

    The dynamics of a seasonally formed salt-wedge propagating along the micro-tidal channel of Strymon River estuary, Northern Greece, and its consequences on river water quality, are thoroughly studied through intensive sampling campaigns. The wedge is developed at the downstream river part, under the summer limited freshwater discharge conditions ( Q < 30 m 3/s). The geometric features of the wedge (length and thickness) appeared directly related to Strymon River discharge. A maximum intrusion length of 4.7 km along Strymon River estuary was observed under minimum river discharge of almost 6 m 3/s. Relations produced from in situ data illustrate that limited river flow expands the wedge horizontally, reducing its vertical dimension, while higher flows lead to increased wedge thickness. Estuarine flushing time ranges between 0.2 and 1.5 days, exponentially dependent on Strymon River discharge. Wedge velocities depicted tidal asymmetry between tidal phases, with consistent inward motion, even under the ebb tidal stage. Strong vertical stratification prevails throughout the tidal cycle, proving the limited vertical mixing between the two layers, although higher interfacial stresses are produced in ebb. Bottom topography plays an interesting role in wedge propagation, as the presence of an underwater sill either prevents saline intrusion during flood or isolates the front of the wedge from its core at the ebb. Ecological consequences of salt-wedge propagation in Strymon River estuary are the frequent evidence of bottom hypoxic conditions and the increased TSS levels, leading to the occurrence of a turbidity maximum at the tip of the salt-wedge. Higher BOD and ammonium levels were mostly observed at the river end, associated to point and non-point pollution sources. Nitrates and silicates were found associated with freshwater fluxes, while ammonia levels were related to saline intrusions. The reduced phosphorus freshwater fluxes, resulting from phosphorus uptake at the

  17. The Río de la Plata estuary response to wind variability in synoptic time scale: Salinity fields and salt wedge structure

    NASA Astrophysics Data System (ADS)

    Meccia, V. L.; Simionato, C. G.; Guerrero, R. A.

    2009-04-01

    The Río de la Plata estuary is located in the eastern coast of southern South America, approximately at 35° S. It has a northwest to southeast oriented funnel shape approximately 300 km long that narrows from 220 km at its mouth to 40 km at its upper end. With a mean discharge of 25,000 m3 s-1 and a drainage area of 3.5 × 106 km2 it ranks fourth and fifth worldwide in freshwater discharge and drainage area, respectively. The interaction between estuarine and shelf waters originates an intense and active salinity front which plays an important role in the flow dynamics and the distribution of properties on the shelf. As a result of the constant displacement of the surface front and the steadiness of the bottom front whose location is controlled by the bathymetry, a time-variable salt wedge structure is observed in the estuary during most of the year. In this work, Estuary, Coastal and Ocean Model (ECOM) was applied to study the processes associated to the salinity fields and the salt wedge structure in the Río de la Plata estuary. It was found that salinity fields in the Río de la Plata rapidly respond -order of 3 days- to wind variability. Therefore, the traditional conceptual scheme that considers seasonal variability as the main feature of the salinity field in this estuary does not longer hold and conditions classically though as characteristic of ‘winter' or ‘summer' can take place during any season with high variability. The estuary response to wind variability can be explained in terms of four characteristic patterns associated to winds that blow with dominant components perpendicular and parallel to the estuary axis. Northeasterly winds produce a southwestward retraction of the surface salinity front. The results are consistent with upwelling motion along the Uruguayan coast under this wind direction. Southwesterly winds produce a northward displacement of the surface salinity front towards the Uruguayan coast and, according to our simulations, a

  18. Evidence of Arc Magma Genesis in a Paleo-Mantle Wedge, the Higashi-Akaishi Peridotite, Japan

    NASA Astrophysics Data System (ADS)

    Till, C. B.; Guild, M. R.; Grove, T. L.; Carlson, R. W.

    2014-12-01

    Located in the Sanbagawa subduction-related high-pressure metamorphic belt in SW Japan on the island of Shikoku, the Higashi-akaishi peridotite body is composed of dunite, lherzolite and garnet clinopyroxenite, interfingered in one locality with quartz-rich eclogite. Previous work indicates the P-T history of the peridotite includes rapid prograde metamorphism with peak temperatures of 700-810°C and pressures of 2.9-3.8 GPa [1] at ~88-89 Ma followed by rapid exhumation at >2.5 cm/yr [2,3]. Major and trace element and isotopic data from samples within the Higashi-akaishi peridotite presented here and in another recent study [4] provide a record of subduction zone melting processes in a paleo-mantle wedge. Ultramafic samples range from 40-52 wt.% SiO2, 1-11 wt.% Al2O3 and 21-45 wt.% MgO with olivine and clinopyroxene Mg#'s as high as 0.93. The quartz-rich eclogite contains 62 wt.% SiO2, 6 wt.% MgO and 13 wt.% Al2O3 with trace element concentrations that are enriched relative to the ultramafic samples. 87Sr/86Sr (.703237-.704288), 143Nd/144Nd (ɛNd=+2 to +6) and Pb isotopic compositions are within the range of previously studied Japanese arc rocks. We interpret the pyroxenites as shallowly crystallized cumulates with varying amounts of trapped hydrous melt and the harzburgites as residues of melting. The peak P-T conditions of these rocks are similar to the solidus conditions of H2O-saturated fertile mantle near the base of the mantle wedge [5,6]. The presence of garnet porphyroblasts that enclose primary euhedral chlorite together with the chemical evidence, suggest these samples are associated with mantle melting in the presence of H2O. Major element modeling suggests the quartz-rich eclogite composition can be reproduced through mixing melts of subducted sediment with wet peridotite melts in the mantle wedge. Thus the Higashi-aikashi rock suite provides an in-situ record of the beginnings of hydrous melting and the mechanisms of metasomatism in the mantle wedge

  19. Stress and displacement fields in the outer wedge induced by megathrust earthquakes

    NASA Astrophysics Data System (ADS)

    Fukao, Yoshio; Hori, Takane; Kodaira, Shuichi

    2014-05-01

    We model plate boundary slip at the outer (oceanward) segment of the megathrust wedge as slip at the base of a two-dimensional elastic wedge, subject to gravity force, with a sloping seafloor at the top, and drag at the bottom from a rigid plate in frictional contact. The stress and displacement fields in the wedge are given analytically as functions of basal frictional coefficient μe. Unlike either conventional dislocation models (constant slip) or crack models (constant stress drop), our wedge model (constant μe drop) does not show a stress singularity at the updip toe of the plate boundary. The slip increases, but the stress drop decreases updip along the fault toward the trench axis. There is a minimum stress difference state in the wedge when μe is varied. By referring to this state (μe = μec), the stress state is separated into a horizontally tensile regime (μe < μec) and a horizontally compressional regime (μe > μec). Slip associated with a μe drop in the range μe ≤ μec occurs toward increasing horizontal tension and shear energy. Such earthquakes include tsunami earthquakes occurring in the outer segment and the 2011 great Tohoku-Oki earthquake, which involved both the outer and inner segments, with much larger slip in the outer segment. These earthquakes are characterized by an almost complete drop of basal stress, which brings the wedge into the maximum tensile state, leading to the rare occurrence of thrust aftershocks at the base of the wedge and frequent occurrence of normal fault aftershocks within the wedge.

  20. The effect of a dynamic wedge in the medial tangential field upon the contralateral breast dose

    SciTech Connect

    McParland, B.J. )

    1990-12-01

    The elevated incidence of breast cancer following irradiation of breast tissue has led to concern over the magnitude of the scattered radiation received by the uninvolved contralateral breast during radiation therapy for a primary breast lesion and the risk of an induced contralateral breast cancer. Some linear accelerators use a single dynamic (or universal) wedge that is mounted within the treatment head at an extended distance from the patient. Because of the combined effects of distance and shielding, the contralateral breast dose due to a medial tangent containing a dynamic wedge is expected to be less than that containing a conventional wedge. This paper presents contralateral breast dose (CBD) measurements performed on an anthropomorphic phantom with breast prostheses irradiated with 6 MV X rays from a linear accelerator equipped with a dynamic wedge. Doses were measured at 15 points within the contralateral breast prosthesis with thermoluminescent dosimeters. It was found that the contralateral breast dose per unit target breast dose decreases with the perpendicular distance from the posterior edge of the medial tangent to the dose measurement point and increases with effective wedge angle by factors ranging up to 2.8, in agreement with data presented earlier for a water phantom geometry. This dose elevation showed no statistically significant dependence (p less than 0.05) upon the perpendicular distance from the beam edge. Comparisons with data in the literature show that the contralateral breast dose increase by a dynamic wedge is typically only about half of that reported for a conventional wedge for the same wedge angle and distance from the beam.

  1. Active shortening within the Himalayan orogenic wedge implied by the 2015 Gorkha earthquake

    NASA Astrophysics Data System (ADS)

    Whipple, Kelin X.; Shirzaei, Manoochehr; Hodges, Kip V.; Ramon Arrowsmith, J.

    2016-09-01

    Models of Himalayan neotectonics generally attribute active mountain building to slip on the Himalayan Sole Thrust, also termed the Main Himalayan Thrust, which accommodates underthrusting of the Indian Plate beneath Tibet. However, the geometry of the Himalayan Sole Thrust and thus how slip along it causes uplift of the High Himalaya are unclear. We show that the geodetic record of the 2015 Gorkha earthquake sequence significantly clarifies the architecture of the Himalayan Sole Thrust and suggests the need for revision of the canonical view of how the Himalaya grow. Inversion of Gorkha surface deformation reveals that the Himalayan Sole Thrust extends as a planar gently dipping fault surface at least 20-30 km north of the topographic front of the High Himalaya. This geometry implies that building of the high range cannot be attributed solely to slip along the Himalayan Sole Thrust over a steep ramp; instead, shortening within the Himalayan wedge is required to support the topography and maintain rapid rock uplift. Indeed, the earthquake sequence may have included a moderate rupture (Mw 6.9) on an out-of-sequence thrust fault at the foot of the High Himalaya. Such internal deformation is an expected response to sustained, focused rapid erosion, and may be common to most compressional orogens.

  2. Breakdown in helium in high-voltage open discharge with subnanosecond current front rise

    NASA Astrophysics Data System (ADS)

    Schweigert, I. V.; Alexandrov, A. L.; Bokhan, P. A.; Zakrevskiy, Dm. E.

    2016-07-01

    Investigations of high-voltage open discharge in helium have shown a possibility of generation of current pulses with subnanosecond front rise, due to ultra-fast breakdown development. The open discharge is ignited between two planar cathodes with mesh anode in the middle between them. For gas pressure 6 Torr and 20 kV applied voltage, the rate of current rise reaches 500 A/(cm2 ns) for current density 200 A/cm2 and more. The time of breakdown development was measured for different helium pressures and a kinetic model of breakdown in open discharge is presented, based on elementary reactions for electrons, ions and fast atoms. The model also includes various cathode emission processes due to cathode bombardment by ions, fast atoms, electrons and photons of resonant radiation with Doppler shift of frequency. It is shown, that the dominating emission processes depend on the evolution of the discharge voltage during the breakdown. In the simulations, two cases of voltage behavior were considered: (i) the voltage is kept constant during the breakdown; (ii) the voltage is reduced with the growth of current. For the first case, the exponentially growing current is maintained due to photoemission by the resonant photons with Doppler-shifted frequency. For the second case, the dominating factor of current growth is the secondary electron emission. In both cases, the subnanosecond rise of discharge current was obtained. Also the effect of gas pressure on breakdown development was considered. It was found that for 20 Torr gas pressure the time of current rise decreases to 0.1 ns, which is in agreement with experimental data.

  3. Thrust fault segmentation and downward fault propagation in accretionary wedges: New Insights from 3D seismic reflection data

    NASA Astrophysics Data System (ADS)

    Orme, Haydn; Bell, Rebecca; Jackson, Christopher

    2016-04-01

    The shallow parts of subduction megathrust faults are typically thought to be aseismic and incapable of propagating seismic rupture. The 2011 Tohoku-Oki earthquake, however, ruptured all the way to the trench, proving that in some locations rupture can propagate through the accretionary wedge. An improved understanding of the structural character and physical properties of accretionary wedges is therefore crucial to begin to assess why such anomalously shallow seismic rupture occurs. Despite its importance, we know surprisingly little regarding the 3D geometry and kinematics of thrust network development in accretionary prisms, largely due to a lack of 3D seismic reflection data providing high-resolution, 3D images of entire networks. Thus our current understanding is largely underpinned by observations from analogue and numerical modelling, with limited observational data from natural examples. In this contribution we use PSDM, 3D seismic reflection data from the Nankai margin (3D Muroto dataset, available from the UTIG Academic Seismic Portal, Marine Geoscience Data System) to examine how imbricate thrust fault networks evolve during accretionary wedge growth. We unravel the evolution of faults within the protothrust and imbricate thrust zones by interpreting multiple horizons across faults and measuring fault displacement and fold amplitude along-strike; by doing this, we are able to investigate the three dimensional accrual of strain. We document a number of local displacement minima along-strike of faults, suggesting that, the protothrust and imbricate thrusts developed from the linkage of smaller, previously isolated fault segments. Although we often assume imbricate faults are likely to have propagated upwards from the décollement we show strong evidence for fault nucleation at shallow depths and downward propagation to intersect the décollement. The complex fault interactions documented here have implications for hydraulic compartmentalisation and pore

  4. Backarc spreading and mantle wedge flow beneath the Japan Sea: insight from Rayleigh-wave anisotropic tomography

    NASA Astrophysics Data System (ADS)

    Liu, Xin; Zhao, Dapeng

    2016-10-01

    We present the first high-resolution Rayleigh-wave phase-velocity azimuthal anisotropy tomography of the Japan subduction zone at periods of 20-150 s, which is determined using a large number of high-quality amplitude and phase data of teleseismic fundamental-mode Rayleigh waves. The obtained 2-D anisotropic phase-velocity models are then inverted for a 3-D shear-wave velocity azimuthal anisotropy tomography down to a depth of ˜300 km beneath Japan. The subducting Pacific slab is imaged as a dipping high-velocity zone with trench-parallel fast-velocity directions (FVDs) which may indicate the anisotropy arising from the normal faults produced at the outer-rise area near the Japan trench axis, overprinting the slab fossil fabric, whereas the mantle wedge generally exhibits lower velocities with trench-normal FVDs which reflect subduction-driven corner flow and anisotropy. Depth variations of azimuthal anisotropy are revealed in the big mantle wedge beneath the Japan Sea, which may reflect past deformations in the Eurasian lithosphere related to backarc spreading during 21 to 15 Ma and complex current convection in the asthenosphere induced by active subductions of both the Pacific and Philippine Sea plates.

  5. Inside the subduction factory: Modeling fluid mobile element enrichment in the mantle wedge above a subduction zone

    NASA Astrophysics Data System (ADS)

    Shervais, John W.; Jean, Marlon M.

    2012-10-01

    Enrichment of the mantle wedge above subduction zones with fluid mobile elements is thought to represent a fundamental process in the origin of arc magmas. This "subduction factory" is typically modeled as a mass balance of inputs (from the subducted slab) and outputs (arc volcanics). We present here a new method to model fluid mobile elements, based on the composition of peridotites associated with supra-subduction ophiolites, which form by melt extraction and fluid enrichment in the mantle wedge above nascent subduction zones. The Coast Range ophiolite (CRO), California, is a Jurassic supra-subduction zone ophiolite that preserves mantle lithologies formed in response to hydrous melting. We use high-precision laser ablation ICP-MS analyses of relic pyroxenes from these peridotites to document fluid-mobile element (FME) concentrations, along with a suite of non-fluid mobile elements that includes rare earth and high-field strength elements. In the CRO, fluid-mobile elements are enriched by factors of up to 100× DMM, whereas fluid immobile elements are progressively depleted by melt extraction. The high concentrations of fluid mobile elements in supra-subduction peridotite pyroxene can be attributed to a flux of aqueous fluid or fluid-rich melt phase derived from the subducting slab. To model this enrichment, we derive a new algorithm that calculates the concentration of fluid mobile elements added to the source: C=[C/[[D/(D-PF)]∗[1-(PF/D)

  6. Improve the transconductance of a graphene field-effect transistor by folding graphene into a wedge

    NASA Astrophysics Data System (ADS)

    Cao, Guiming; Liu, Weihua; Cao, Meng; Li, Xin; Zhang, Anping; Wang, Xiaoli; Chen, Bangdao

    2016-07-01

    The transport property of a graphene wedge channel is studied theoretically and its leakage current through field emission is estimated when considering the effect of the internal electric field. The transconductance of the graphene transistor is improved from 0.016 to 0.321 μS μm‑1 when the graphene is folded into a wedge (with angle of wedge π/6 and radius curvature 2.7 nm at the tip), while the wedge height is much smaller than the space between the top-gate and the channel. The improved transconductance is due to the locally enhanced electric field, which results in a potential well and causes electron accumulation at the wedge tip. The leakage current through field emission J FE shows a super-linear increase with the channel conductive current J DS, where overall the electron supply for the field emission at the wedge tip is improved by the channel bias voltage V DS.

  7. Improve the transconductance of a graphene field-effect transistor by folding graphene into a wedge

    NASA Astrophysics Data System (ADS)

    Cao, Guiming; Liu, Weihua; Cao, Meng; Li, Xin; Zhang, Anping; Wang, Xiaoli; Chen, Bangdao

    2016-07-01

    The transport property of a graphene wedge channel is studied theoretically and its leakage current through field emission is estimated when considering the effect of the internal electric field. The transconductance of the graphene transistor is improved from 0.016 to 0.321 μS μm-1 when the graphene is folded into a wedge (with angle of wedge π/6 and radius curvature 2.7 nm at the tip), while the wedge height is much smaller than the space between the top-gate and the channel. The improved transconductance is due to the locally enhanced electric field, which results in a potential well and causes electron accumulation at the wedge tip. The leakage current through field emission J FE shows a super-linear increase with the channel conductive current J DS, where overall the electron supply for the field emission at the wedge tip is improved by the channel bias voltage V DS.

  8. The Effects of a Lateral Wedge Insole on Knee and Ankle Joints During Slope Walking.

    PubMed

    Uto, Yuki; Maeda, Tetsuo; Kiyama, Ryoji; Kawada, Masayuki; Tokunaga, Ken; Ohwatashi, Akihiko; Fukudome, Kiyohiro; Ohshige, Tadasu; Yoshimoto, Yoichi; Yone, Kazunori

    2015-12-01

    The purpose of this study was to determine whether a lateral wedge insole reduces the external knee adduction moment during slope walking. Twenty young, healthy subjects participated in this study. Subjects walked up and down a slope using 2 different insoles: a control flat insole and a 7° lateral wedge insole. A three-dimensional motion analysis system and force plate were used to examine the knee adduction moment, the ankle valgus moment, and the moment arm of the ground reaction force to the knee joint center in the frontal plane. The lateral wedge insole significantly decreased the moment arm of the ground reaction force, resulting in a reduction of the knee adduction moment during slope walking, similar to level walking. The reduction ratio of knee adduction moment by the lateral wedge insole during the early stance of up-slope walking was larger than that of level walking. Conversely, the lateral wedge insole increased the ankle valgus moment during slope walking, especially during the early stance phase of up-slope walking. Clinicians should examine the utilization of a lateral wedge insole for knee osteoarthritis patients who perform inclined walking during daily activity, in consideration of the load on the ankle joint. PMID:26252560

  9. Field observation of low-to-mid-frequency acoustic propagation characteristics of an estuarine salt wedge.

    PubMed

    Reeder, D Benjamin

    2016-01-01

    The estuarine environment often hosts a salt wedge, the stratification of which is a function of the tide's range and speed of advance, river discharge volumetric flow rate, and river mouth morphology. Competing effects of temperature and salinity on sound speed in this stratified environment control the degree of acoustic refraction occurring along an acoustic path. A field experiment was carried out in the Columbia River Estuary to test the hypothesis: the estuarine salt wedge is acoustically observable in terms of low-to-mid-frequency acoustic propagation. Linear frequency-modulated acoustic signals in the 500-2000 Hz band were transmitted during the advance and retreat of the salt wedge during May 27-29, 2013. Results demonstrate that the salt wedge front is the dominant physical mechanism controlling acoustic propagation in this environment: received signal energy is relatively stable before and after the passage of the salt wedge front when the acoustic path consists of a single medium (either entirely fresh water or entirely salt water), and suffers a 10-15 dB loss and increased variability during salt wedge front passage. Physical parameters and acoustic propagation modeling corroborate and inform the acoustic observations. PMID:26827001

  10. A simplistic analytical unit cell based model for the effective thermal conductivity of high porosity open-cell metal foams

    NASA Astrophysics Data System (ADS)

    Yang, X. H.; Kuang, J. J.; Lu, T. J.; Han, F. S.; Kim, T.

    2013-06-01

    We present a simplistic yet accurate analytical model for the effective thermal conductivity of high porosity open-cell metal foams saturated in a low conducting fluid (air). The model is derived analytically based on a realistic representative unit cell (a tetrakaidecahedron) under the assumption of one-dimensional heat conduction along highly tortuous-conducting ligaments at high porosity ranges (ε ⩾ 0.9). Good agreement with existing experimental data suggests that heat conduction along highly conducting and tortuous ligaments predominantly defines the effective thermal conductivity of open-cell metal foams with negligible conduction in parallel through the fluid phase.

  11. MANTA--an open-source, high density electrophysiology recording suite for MATLAB.

    PubMed

    Englitz, B; David, S V; Sorenson, M D; Shamma, S A

    2013-01-01

    The distributed nature of nervous systems makes it necessary to record from a large number of sites in order to decipher the neural code, whether single cell, local field potential (LFP), micro-electrocorticograms (μECoG), electroencephalographic (EEG), magnetoencephalographic (MEG) or in vitro micro-electrode array (MEA) data are considered. High channel-count recordings also optimize the yield of a preparation and the efficiency of time invested by the researcher. Currently, data acquisition (DAQ) systems with high channel counts (>100) can be purchased from a limited number of companies at considerable prices. These systems are typically closed-source and thus prohibit custom extensions or improvements by end users. We have developed MANTA, an open-source MATLAB-based DAQ system, as an alternative to existing options. MANTA combines high channel counts (up to 1440 channels/PC), usage of analog or digital headstages, low per channel cost (<$90/channel), feature-rich display and filtering, a user-friendly interface, and a modular design permitting easy addition of new features. MANTA is licensed under the GPL and free of charge. The system has been tested by daily use in multiple setups for >1 year, recording reliably from 128 channels. It offers a growing list of features, including integrated spike sorting, PSTH and CSD display and fully customizable electrode array geometry (including 3D arrays), some of which are not available in commercial systems. MANTA runs on a typical PC and communicates via TCP/IP and can thus be easily integrated with existing stimulus generation/control systems in a lab at a fraction of the cost of commercial systems. With modern neuroscience developing rapidly, MANTA provides a flexible platform that can be rapidly adapted to the needs of new analyses and questions. Being open-source, the development of MANTA can outpace commercial solutions in functionality, while maintaining a low price-point.

  12. MANTA--an open-source, high density electrophysiology recording suite for MATLAB.

    PubMed

    Englitz, B; David, S V; Sorenson, M D; Shamma, S A

    2013-01-01

    The distributed nature of nervous systems makes it necessary to record from a large number of sites in order to decipher the neural code, whether single cell, local field potential (LFP), micro-electrocorticograms (μECoG), electroencephalographic (EEG), magnetoencephalographic (MEG) or in vitro micro-electrode array (MEA) data are considered. High channel-count recordings also optimize the yield of a preparation and the efficiency of time invested by the researcher. Currently, data acquisition (DAQ) systems with high channel counts (>100) can be purchased from a limited number of companies at considerable prices. These systems are typically closed-source and thus prohibit custom extensions or improvements by end users. We have developed MANTA, an open-source MATLAB-based DAQ system, as an alternative to existing options. MANTA combines high channel counts (up to 1440 channels/PC), usage of analog or digital headstages, low per channel cost (<$90/channel), feature-rich display and filtering, a user-friendly interface, and a modular design permitting easy addition of new features. MANTA is licensed under the GPL and free of charge. The system has been tested by daily use in multiple setups for >1 year, recording reliably from 128 channels. It offers a growing list of features, including integrated spike sorting, PSTH and CSD display and fully customizable electrode array geometry (including 3D arrays), some of which are not available in commercial systems. MANTA runs on a typical PC and communicates via TCP/IP and can thus be easily integrated with existing stimulus generation/control systems in a lab at a fraction of the cost of commercial systems. With modern neuroscience developing rapidly, MANTA provides a flexible platform that can be rapidly adapted to the needs of new analyses and questions. Being open-source, the development of MANTA can outpace commercial solutions in functionality, while maintaining a low price-point. PMID:23653593

  13. MANTA—an open-source, high density electrophysiology recording suite for MATLAB

    PubMed Central

    Englitz, B.; David, S. V.; Sorenson, M. D.; Shamma, S. A.

    2013-01-01

    The distributed nature of nervous systems makes it necessary to record from a large number of sites in order to decipher the neural code, whether single cell, local field potential (LFP), micro-electrocorticograms (μECoG), electroencephalographic (EEG), magnetoencephalographic (MEG) or in vitro micro-electrode array (MEA) data are considered. High channel-count recordings also optimize the yield of a preparation and the efficiency of time invested by the researcher. Currently, data acquisition (DAQ) systems with high channel counts (>100) can be purchased from a limited number of companies at considerable prices. These systems are typically closed-source and thus prohibit custom extensions or improvements by end users. We have developed MANTA, an open-source MATLAB-based DAQ system, as an alternative to existing options. MANTA combines high channel counts (up to 1440 channels/PC), usage of analog or digital headstages, low per channel cost (<$90/channel), feature-rich display and filtering, a user-friendly interface, and a modular design permitting easy addition of new features. MANTA is licensed under the GPL and free of charge. The system has been tested by daily use in multiple setups for >1 year, recording reliably from 128 channels. It offers a growing list of features, including integrated spike sorting, PSTH and CSD display and fully customizable electrode array geometry (including 3D arrays), some of which are not available in commercial systems. MANTA runs on a typical PC and communicates via TCP/IP and can thus be easily integrated with existing stimulus generation/control systems in a lab at a fraction of the cost of commercial systems. With modern neuroscience developing rapidly, MANTA provides a flexible platform that can be rapidly adapted to the needs of new analyses and questions. Being open-source, the development of MANTA can outpace commercial solutions in functionality, while maintaining a low price-point. PMID:23653593

  14. Population connectivity shifts at high frequency within an open-coast marine protected area network.

    PubMed

    Cook, Geoffrey S; Parnell, P Ed; Levin, Lisa A

    2014-01-01

    A complete understanding of population connectivity via larval dispersal is of great value to the effective design and management of marine protected areas (MPA). However empirical estimates of larval dispersal distance, self-recruitment, and within season variability of population connectivity patterns and their influence on metapopulation structure remain rare. We used high-resolution otolith microchemistry data from the temperate reef fish Hypsypops rubicundus to explore biweekly, seasonal, and annual connectivity patterns in an open-coast MPA network. The three MPAs, spanning 46 km along the southern California coastline were connected by larval dispersal, but the magnitude and direction of connections reversed between 2008 and 2009. Self-recruitment, i.e. spawning, dispersal, and settlement to the same location, was observed at two locations, one of which is a MPA. Self-recruitment to this MPA ranged from 50-84%; within the entire 60 km study region, self-recruitment accounted for 45% of all individuals settling to study reefs. On biweekly time scales we observed directional variability in alongshore current data and larval dispersal trajectories; if viewed in isolation these data suggest the system behaves as a source-sink metapopulation. However aggregate biweekly data over two years reveal a reef network in which H. rubicundus behaves more like a well-mixed metapopulation. As one of the few empirical studies of population connectivity within a temperate open coast reef network, this work can inform the MPA design process, implementation of ecosystem based management plans, and facilitate conservation decisions. PMID:25077486

  15. Mud volcano venting induced gas hydrate formation at the upper slope accretionary wedge, offshore SW Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Saulwood; Tseng, Yi-Ting; Cheng, Wan-Yen; Chou, Cheng-Tien; Chen, NeiChen; Hsieh, I.-Chih

    2016-04-01

    TsanYao Mud Volcano (TYMV) is the largest mud volcano cone in the Hengchun Mud Volcano Group (HCMVG), located at the upper slope of the accrretionary wedge, southwest of Taiwan. The region is under active tectonic activity with the Philippine Plate, moving northwestward at a rate of ~8 cm/year. This region also receives huge quantity of suspended particle load of ~100 mT/year at present time from adjacent small rivers of the Island of Taiwan. Large loads of suspended sediments influx become a major source of organic carbon and later gas and other hydrocarbon. Gas and fluid in the mud volcano are actively venting from deep to the sea floor on the upper slope of the accretionary wedge. In order to understand venting on the HCMVG, echo sounder, towcam and coring were carried out. Pore water sulfate, chloride, potassium, calcium, stable isotope O-18, gas compositions, dissolved sulfide were analysed. The HCMVG consists of 12 volcano cones of different sizes. Large quantity of gas and fluid are venting directly from deep to the TYMV structure high, as well as 50+ other vents as appeared as flares on the echo sounder. Some flares are reaching to the atmosphere and likely a source of green house gases to the atmosphere. Venting fluids include gas bubbles, suspended particle, mud, and breccia. Breccia size could reach more than 12 cm in diameter. Circular bands in different color appeared around the cone may represent stages of vent eruptions. Compositions of vent gas include methane, ethane and propane. High proportions of ethane and propane in the vent gas demonstrated that source of gas are thermogenic in origin. Patchy authigenic carbonate, bacterial mats, bivalves, tube worms and other chemosynthesis organisms were supported by venting gas AOM process near the sea floor. Pore water chloride concentrations show distinct variation pattern from center cone to the side of the volcano, with low in the center and high away from the cone. Pore water with higher than seawater

  16. Benzothiadiazole-based polymer for single and double junction solar cells with high open circuit voltage.

    PubMed

    Venkatesan, Swaminathan; Ngo, Evan C; Chen, Qiliang; Dubey, Ashish; Mohammad, Lal; Adhikari, Nirmal; Mitul, Abu Farzan; Qiao, Qiquan

    2014-06-21

    Single and double junction solar cells with high open circuit voltage were fabricated using poly{thiophene-2,5-diyl-alt-[5,6-bis(dodecyloxy)benzo[c][1,2,5]thiadiazole]-4,7-diyl} (PBT-T1) blended with fullerene derivatives in different weight ratios. The role of fullerene loading on structural and morphological changes was investigated using atomic force microscopy (AFM) and X-ray diffraction (XRD). The XRD and AFM measurements showed that a higher fullerene mixing ratio led to breaking of inter-chain packing and hence resulted in smaller disordered polymer domains. When the PBT-T1:PC60BM weight ratio was 1 : 1, the polymer retained its structural order; however, large aggregated domains formed, leading to poor device performance due to low fill factor and short circuit current density. When the ratio was increased to 1 : 2 and then 1 : 3, smaller amorphous domains were observed, which improved photovoltaic performance. The 1 : 2 blending ratio was optimal due to adequate charge transport pathways giving rise to moderate short circuit current density and fill factor. Adding 1,8-diiodooctane (DIO) additive into the 1 : 2 blend films further improved both the short circuit current density and fill factor, leading to an increased efficiency to 4.5% with PC60BM and 5.65% with PC70BM. These single junction solar cells exhibited a high open circuit voltage at ∼ 0.9 V. Photo-charge extraction by linearly increasing voltage (Photo-CELIV) measurements showed the highest charge carrier mobility in the 1 : 2 film among the three ratios, which was further enhanced by introducing the DIO. The Photo-CELIV measurements with varying delay times showed significantly higher extracted charge carrier density for cells processed with DIO. Tandem devices using P3HT:IC60BA as bottom cell and PBT-T1:PC60BM as top cell exhibited a high open circuit voltage of 1.62 V with 5.2% power conversion efficiency. PMID:24844939

  17. Modes of continental extension in a lithospheric wedge

    NASA Astrophysics Data System (ADS)

    Wu, G.; Lavier, L. L.; Choi, E.

    2014-12-01

    We studied extension of a lithospheric wedge as an approximation to an orogenic belt or a continental margin. We ran a series of numerical models to quantify the effects of the strength of the lower crust and a mid-crustal shear zone (MCSZ) on the extension processes. When the MCSZ is present, we found that the regional lower crustal flow plays a critical role in controlling the modes of extension. The compensation is long-wavelength when the lower crust flows from the highest to the lowest elevation in order to compensate upper crustal thinning. In response to this motion, the mantle flows towards the highest elevation in order to balance for the lower crust leaving the area under the highest topography. For weak (wet quartz regime with partial melting) or intermediate (wet quartz regime), or strong (dry quartz regime) lower crust, we recognized three predominantly decoupled modes of extension characterized by 1) significant lower crustal exhumation exemplified as a large massif, 2) formation of core complexes and detachment faults, and 3) distributive domino faulting, respectively. Without the MCSZ, however, the lower crustal flow is essentially subdued with predominantly coupled extension. For weak or intermediate, or strong lower crust, we recognized three coupled modes characterized by 1) localized generally symmetric crustal exhumation, 2) distributed grabens and narrow rifts, and 3) wide continental margins, respectively. The MCSZ controls the degree of decoupling of the lower crustal flow such that a frictionally stronger MCSZ does not change the behaviors of the models but results in a more distributed extension. Due to the long-wavelength compensation, subhorizontal Moho is achieved where intensive extension occurred for all the decoupled models with a MCSZ. Natural counterparts for each mode may be easily identified, for instance, in the Basin and Range or the Aegean.

  18. Grounding zone wedges, Kveithola Trough (NW Barents Sea)

    NASA Astrophysics Data System (ADS)

    Rebesco, Michele; Urgeles, Roger; Özmaral, Asli; Hanebuth, Till; Caburlotto, Andrea; Hörner, Tanja; Lantzsch, Hendrik; LLopart, Juame; Lucchi, Renata; Skøtt Nicolaisen, Line; Giacomo, Osti; Sabbatini, Anna; Camerlenghi, Angelo

    2014-05-01

    Swath bathymetry within Kveithola Trough (NW Barents Sea) shows a seafloor characterized by E-W trending megascale glacial lineations (MSGLs) overprinted by transverse Grounding Zone Wedges (GZWs), which give the trough a stair profile (Rebesco et al., 2011). GZWs are formed by deposition of subglacial till at temporarily stable ice-stream fronts in between successive episodic retreats (Rüther et al., 2012; Bjarnadóttir et al., 2012). Sub-bottom data show that present-day morphology is largely inherited from palaeo-seafloor topography of GZWs, which is draped by a deglacial to early Holocene glaciomarine sediments (about 15 m thick). The ice stream that produced such subglacial morphology was flowing from East to West inside Kveithola Trough during Last Glacial Maximum. Its rapid retreat was likely associated with progressive lift-offs, and successive rapid melting of the grounded ice, induced by the eustatic sea-level rise (Lucchi et al., 2013). References: Bjarnadóttir, L.R., Rüther, D.C., Winsborrow, M.C.M., Andreassen, K., 2012. Grounding-line dynamics during the last deglaciation of Kveithola, W Barents Sea, as revealed by seabed geomorphology and shallow seismic stratigraphy. Boreas, 42, 84-107. Lucchi R.G., et al. 2013. Postglacial sedimentary processes on the Storfjorden and Kveithola TMFs: impact of extreme glacimarine sedimentation. Global and Planetary Change, 111, 309-326. Rebesco, M., et al. 2011. Deglaciation of the Barents Sea Ice Sheet - a swath bathymetric and subbottom seismic study from the Kveitehola Trough. Marine Geology, 279, 141-14. Rüther, D.C., Bjarnadóttir, L.R., Junttila, J., Husum, K., Rasmussen, T.L., Lucchi, R.G., Andreassen, K., 2012. Pattern and timing of the north-western Barents Sea Ice Sheet deglaciation and indications of episodic Holocene deposition. Boreas 41, 494-512.

  19. Saline Fluids in Subduction Channels and Mantle Wedge

    NASA Astrophysics Data System (ADS)

    Kawamoto, T.; Hertwig, A.; Schertl, H. P.; Maresch, W. V.; Shigeno, M.; Mori, Y.; Nishiyama, T.

    2015-12-01

    Saline fluids can transport large-ion-lithophile elements and carbonate. Subduction-zone fluids contain salts with various amounts of NaCl equivalent similar to that of the present and/or Phanerozoic seawater (about 3.5 wt% NaCl). The salinity of aqueous fluids in the mantle wedge decreases from trench side to back-arc side, although available data have been limited. Such saline fluids from mantle peridotite underneath Pinatubo, a frontal volcano of the Luzon arc, contain 5.1 wt% NaCl equivalent and CO2 [Kawamoto et al., 2013 Proc Natl Acad Sci USA] and in Ichinomegeta, a rear-arc volcano of the Northeast Japan arc, contain 3.7 wt% NaCl equivalent and CO2 [Kumagai et al., Contrib Mineral Petrol 2014]. Abundances of chlorine and H2O in olivine-hosted melt inclusions also suggest that aqueous fluids to produce frontal basalts have higher salinity than rear-arc basalts in Guatemala arc [Walker et al., Contrib Mineral Petrol 2003]. In addition to these data, quartz-free jadeitites contain fluid inclusions composed of aqueous fluids with 7 wt% NaCl equivalent and quartz-bearing jadeitite with 4.6 wt% NaCl equivalent in supra-subduction zones in Southwest Japan [Mori et al., 2015, International Eclogite Conference] and quartz-bearing jadeitite and jadeite-rich rocks contain fluid inclusions composed of aqueous fluids with 4.2 wt% NaCl equivalent in Rio San Juan Complex, Dominica Republic [Kawamoto et al., 2015, Goldschmidt Conference]. Aqueous fluids generated at pressures lower than conditions for albite=jadeite+quartz occurring at 1.5 GPa, 500 °C may contain aqueous fluids with higher salinity than at higher pressures.

  20. Flow Pattern relative to the Substorm Current Wedge

    NASA Astrophysics Data System (ADS)

    Chu, X.; McPherron, R. L.; Hsu, T.

    2013-12-01

    Magnetospheric substorms play a key role in the coupling of the solar wind and the magnetosphere. The Substorm Current Wedge (SCW) is a key element in the present physical model of substorms. It is widely accepted that the SCW is created by earthward busty flows, but the generation mechanism is still unknown. Previous studies suggest pressure gradients and magnetic vortices are possible candidates. Due to the sparse coverage of satellites in space, these studies were strongly dependent on the assumption that the satellites were in the generation region of the field-aligned currents (FAC) forming the SCW. In this work, we take advantage of an inversion technique that determines the parameters describing the SCW and perform a statistical study on the plasma and magnetic field parameters of the flow pattern relative to the SCW. The inversion technique finds the location and the intensity of the SCW from midlatitude magnetic data. The technique has been validated using auroral observations, Equivalent Ionospheric Currents (EIC), SYM-H index from SuperMAG, and magnetic perturbations at geosynchronous orbit by the GOES satellite. A database of substorm events has been created using midlatitude positive bays, which are the ground signature of the SCW at lower latitudes. The inversion technique is applied to each event in the database to determine the location of the origin of the SCW. The inversion results are also used to find conjunction events with space observations from VAP (RBSP), THEMIS and GOES. The plasma and magnetic field parameters such as the pressure gradient and magnetic vorticity are then categorized as a function of their location relative to the origin of the SCW. How the distribution/pattern of the pressure gradient and vorticity are related to the properties of the SCW (locations and intensity of the FAC), and flows (entropy, velocity and density) will be determined.

  1. Discrete dislocation plasticity analysis of the wedge indentation of films

    NASA Astrophysics Data System (ADS)

    Balint, D. S.; Deshpande, V. S.; Needleman, A.; Van der Giessen, E.

    2006-11-01

    The plane strain indentation of single crystal films on a rigid substrate by a rigid wedge indenter is analyzed using discrete dislocation plasticity. The crystals have three slip systems at ±35.3∘ and 90∘ with respect to the indentation direction. The analyses are carried out for three values of the film thickness, 2, 10 and 50 μm, and with the dislocations all of edge character modeled as line singularities in a linear elastic material. The lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and dislocation annihilation are incorporated through a set of constitutive rules. Over the range of indentation depths considered, the indentation pressure for the 10 and 50 μm thick films decreases with increasing contact size and attains a contact size-independent value for contact lengths A>4 μm. On the other hand, for the 2 μm films, the indentation pressure first decreases with increasing contact size and subsequently increases as the plastic zone reaches the rigid substrate. For the 10 and 50 μm thick films sink-in occurs around the indenter, while pile-up occurs in the 2 μm film when the plastic zone reaches the substrate. Comparisons are made with predictions obtained from other formulations: (i) the contact size-independent indentation pressure is compared with that given by continuum crystal plasticity; (ii) the scaling of the indentation pressure with indentation depth is compared with the relation proposed by Nix and Gao [1998. Indentation size effects in crystalline materials: a law for strain gradient plasticity. J. Mech. Phys. Solids 43, 411-423]; and (iii) the computed contact area is compared with that obtained from the estimation procedure of Oliver and Pharr [1992. An improved technique for determining hardness and elastic-modulus using load and displacement sensing indentation experiments, J. Mater. Res. 7, 1564-1583].

  2. Forward Versus Back Thrusts in Accretionary Wedges: Effects of Rheology and Thickness of the Décollement Layer

    NASA Astrophysics Data System (ADS)

    Ito, Garrett; Olive, Jean-Arthur; Moore, Gregory; Gutscher, Marc-Andre; Weiss, Jonathan

    2016-04-01

    The mechanical processes that control whether major thrusts in accretionary wedges verge forward toward the foreland, versus backward toward the hinterland has long been a topic of debate. Whereas forethrusts are the most common major thrusts, the importance of the globally rare back thrusts has recently been highlighted given their prominence along the Cascadia margin off of the NW coast of North America as well as along the Andaman-Sumatra subduction zone, in the rupture area of the great 2004 earthquake. We address this problem using 2-D numerical models that use a finite-difference, particle-in-cell method with a viscoelastic-plastic rheology for simulating thrusting in accretionary wedges. Simulations of a weak frictional décollement confirm prior numerical and analogue modeling studies in that they predict lower wedge tapers and repeated sequences of doubly verging conjugate thrusts. A forward dipping backstop was shown in prior laboratory experiments to promote backthrusting, and our results confirm that backthrusting occurs near the backstop but as the wedge widens away from the backstop forethrusts become dominant. Other laboratory experimental studies have found that a non-brittle, viscously deforming décollement can promote backthrusting. Our numerical models show that if the viscosity of the décollement layer η is too high, such that the stress scale, ηU/H (where U is the convergence rate and H is the décollement layer thickness), is comparable to the frictional strength at the base, then forethrusts dominate. For ηU/H less than the basal frictional strength, doubly verging faults are prominent over a wide range of décollement layer thicknesses. Only for cases with relatively low ηU/H and décollement layer thicknesses H that are 25-33% of the thickness of the whole, incoming sediment layer do backthrusts dominate. Thus backthrusting appears to require unusual rheological properties of the deepest sediments, which is consistent with the rarity

  3. MRF Applications: Measurement of Process-dependent Subsurface Damage in Optical Materials using the MRF Wedge Technique

    SciTech Connect

    Menapace, J A; Davis, P J; Steele, W A; Wong, L L; Suratwala, T I; Miller, P E

    2005-11-02

    Understanding the behavior of fractures and subsurface damage in the processes used during optic fabrication plays a key role in determining the final quality of the optical surface finish. During the early stages of surface preparation, brittle grinding processes induce fractures at or near an optical surface whose range can extend from depths of a few mm to hundreds of mm depending upon the process and tooling being employed. Controlling the occurrence, structure, and propagation of these sites during subsequent grinding and polishing operations is highly desirable if one wishes to obtain high-quality surfaces that are free of such artifacts. Over the past year, our team has made significant strides in developing a diagnostic technique that combines magnetorheological finishing (MRF) and scanning optical microscopy to measure and characterize subsurface damage in optical materials. The technique takes advantage of the unique nature of MRF to polish a prescribed large-area wedge into the optical surface without propagating existing damage or introducing new damage. The polished wedge is then analyzed to quantify subsurface damage as a function of depth from the original surface. Large-area measurement using scanning optical microscopy provides for improved accuracy and reliability over methods such as the COM ball-dimple technique. Examples of the technique's use will be presented that illustrate the behavior of subsurface damage in fused silica that arises during a variety of intermediate optical fabrication process steps.

  4. HTSstation: A Web Application and Open-Access Libraries for High-Throughput Sequencing Data Analysis

    PubMed Central

    David, Fabrice P. A.; Delafontaine, Julien; Carat, Solenne; Ross, Frederick J.; Lefebvre, Gregory; Jarosz, Yohan; Sinclair, Lucas; Noordermeer, Daan; Rougemont, Jacques; Leleu, Marion

    2014-01-01

    The HTSstation analysis portal is a suite of simple web forms coupled to modular analysis pipelines for various applications of High-Throughput Sequencing including ChIP-seq, RNA-seq, 4C-seq and re-sequencing. HTSstation offers biologists the possibility to rapidly investigate their HTS data using an intuitive web application with heuristically pre-defined parameters. A number of open-source software components have been implemented and can be used to build, configure and run HTS analysis pipelines reactively. Besides, our programming framework empowers developers with the possibility to design their own workflows and integrate additional third-party software. The HTSstation web application is accessible at http://htsstation.epfl.ch. PMID:24475057

  5. An informatics infrastructure for combinatorial and high-throughput materials research built on open source code

    NASA Astrophysics Data System (ADS)

    Zhang, Wenhua; Fasolka, Michael J.; Karim, Alamgir; Amis, Eric J.

    2005-01-01

    Laboratory research informatics systems (LRIS) hold great promise in streamlining research generally, and are absolutely necessary for new data-intensive research strategies such as combinatorial and high-throughput (C&HT) approaches. In this paper, we describe a LRIS geared towards C&HT materials research, which is being established in lab facilities at the NIST Combinatorial Method Center (NCMC). The NCMC LRIS system aims to seamlessly integrate the library design, fabrication, measurement and analysis/data-mining aspects of the combi approach into a functional whole geared towards accelerating materials research. Our LRIS system is built upon an open source database management system, and incorporates non-proprietary user/instrument interface and automation software. The NCMC LRIS project endeavours to provide working examples of informatics infrastructure development to those interested in assimilating such tools into their research programmes. Accordingly, this report aims at providing an experiential account of the process by which we designed and implemented the NCMC LRIS.

  6. Cost Effective Open Geometry HTS MRI System amended to BSCCO 2212 Wire for High Field Magnets

    SciTech Connect

    Kennth Marken

    2006-08-11

    The original goal of this Phase II Superconductivity Partnership Initiative project was to build and operate a prototype Magnetic Resonance Imaging (MRI) system using high temperature superconductor (HTS) coils wound from continuously processed dip-coated BSCCO 2212 tape conductor. Using dip-coated tape, the plan was for MRI magnet coils to be wound to fit an established commercial open geometry, 0.2 Tesla permanent magnet system. New electronics and imaging software for a prototype higher field superconducting system would have added significantly to the cost. However, the use of the 0.2 T platform would allow the technical feasibility and the cost issues for HTS systems to be fully established. Also it would establish the energy efficiency and savings of HTS open MRI compared with resistive and permanent magnet systems. The commercial goal was an open geometry HTS MRI running at 0.5 T and 20 K. This low field open magnet was using resistive normal metal conductor and its heat loss was rather high around 15 kolwatts. It was expected that an HTS magnet would dissipate around 1 watt, significantly reduce power consumption. The SPI team assembled to achieve this goal was led by Oxford Instruments, Superconducting Technology (OST), who developed the method of producing commercial dip coated tape. Superconductive Components Inc. (SCI), a leading US supplier of HTS powders, supported the conductor optimization through powder optimization, scaling, and cost reduction. Oxford Magnet Technology (OMT), a joint venture between Oxford Instruments and Siemens and the world’s leading supplier of MRI magnet systems, was involved to design and build the HTS MRI magnet and cryogenics. Siemens Magnetic Resonance Division, a leading developer and supplier of complete MRI imaging systems, was expected to integrate the final system and perform imaging trials. The original MRI demonstration project was ended in July 2004 by mutual consent of Oxford Instruments and Siemens. Between

  7. Three-Dimensional Vertebral Wedging in Mild and Moderate Adolescent Idiopathic Scoliosis

    PubMed Central

    Scherrer, Sophie-Anne; Begon, Mickaël; Leardini, Alberto; Coillard, Christine; Rivard, Charles-Hilaire; Allard, Paul

    2013-01-01

    Background Vertebral wedging is associated with spinal deformity progression in adolescent idiopathic scoliosis. Reporting frontal and sagittal wedging separately could be misleading since these are projected values of a single three-dimensional deformation of the vertebral body. The objectives of this study were to determine if three-dimensional vertebral body wedging is present in mild scoliosis and if there are a preferential vertebral level, position and plane of deformation with increasing scoliotic severity. Methodology Twenty-seven adolescent idiopathic scoliotic girls with mild to moderate Cobb angles (10° to 50°) participated in this study. All subjects had at least one set of bi-planar radiographs taken with the EOS® X-ray imaging system prior to any treatment. Subjects were divided into two groups, separating the mild (under 20°) from the moderate (20° and over) spinal scoliotic deformities. Wedging was calculated in three different geometric planes with respect to the smallest edge of the vertebral body. Results Factorial analyses of variance revealed a main effect for the scoliosis severity but no main effect of vertebral Levels (apex and each of the three vertebrae above and below it) (F = 1.78, p = 0.101). Main effects of vertebral Positions (apex and above or below it) (F = 4.20, p = 0.015) and wedging Planes (F = 34.36, p<0.001) were also noted. Post-hoc analysis demonstrated a greater wedging in the inferior group of vertebrae (3.6°) than the superior group (2.9°, p = 0.019) and a significantly greater wedging (p≤0.03) along the sagittal plane (4.3°). Conclusions Vertebral wedging was present in mild scoliosis and increased as the scoliosis progressed. The greater wedging of the inferior group of vertebrae could be important in estimating the most distal vertebral segment to be restrained by bracing or to be fused in surgery. Largest vertebral body wedging values obtained in the sagittal plane support the claim

  8. High-frequency asymptotic methods for analyzing the EM scattering by open-ended waveguide cavities

    NASA Technical Reports Server (NTRS)

    Burkholder, R. J.; Pathak, P. H.

    1989-01-01

    Four high-frequency methods are described for analyzing the electromagnetic (EM) scattering by electrically large open-ended cavities. They are: (1) a hybrid combination of waveguide modal analysis and high-frequency asymptotics, (2) geometrical optics (GO) ray shooting, (3) Gaussian beam (GB) shooting, and (4) the generalized ray expansion (GRE) method. The hybrid modal method gives very accurate results but is limited to cavities which are made up of sections of uniform waveguides for which the modal fields are known. The GO ray shooting method can be applied to much more arbitrary cavity geometries and can handle absorber treated interior walls, but it generally only predicts the major trends of the RCS pattern and not the details. Also, a very large number of rays need to be tracked for each new incidence angle. Like the GO ray shooting method, the GB shooting method can handle more arbitrary cavities, but it is much more efficient and generally more accurate than the GO method because it includes the fields diffracted by the rim at the open end which enter the cavity. However, due to beam divergence effects the GB method is limited to cavities which are not very long compared to their width. The GRE method overcomes the length-to-width limitation of the GB method by replacing the GB's with GO ray tubes which are launched in the same manner as the GB's to include the interior rim diffracted field. This method gives good accuracy and is generally more efficient than the GO method, but a large number of ray tubes needs to be tracked.

  9. Does Human Body Odor Represent a Significant and Rewarding Social Signal to Individuals High in Social Openness?

    PubMed Central

    Lübke, Katrin T.; Croy, Ilona; Hoenen, Matthias; Gerber, Johannes; Pause, Bettina M.; Hummel, Thomas

    2014-01-01

    Across a wide variety of domains, experts differ from novices in their response to stimuli linked to their respective field of expertise. It is currently unknown whether similar patterns can be observed with regard to social expertise. The current study therefore focuses on social openness, a central social skill necessary to initiate social contact. Human body odors were used as social cues, as they inherently signal the presence of another human being. Using functional MRI, hemodynamic brain responses to body odors of women reporting a high (n = 14) or a low (n = 12) level of social openness were compared. Greater activation within the inferior frontal gyrus and the caudate nucleus was observed in high socially open individuals compared to individuals low in social openness. With the inferior frontal gyrus being a crucial part of the human mirror neuron system, and the caudate nucleus being implicated in social reward, it is discussed whether human body odor might constitute more of a significant and rewarding social signal to individuals high in social openness compared to individuals low in social openness process. PMID:24718308

  10. Does human body odor represent a significant and rewarding social signal to individuals high in social openness?

    PubMed

    Lübke, Katrin T; Croy, Ilona; Hoenen, Matthias; Gerber, Johannes; Pause, Bettina M; Hummel, Thomas

    2014-01-01

    Across a wide variety of domains, experts differ from novices in their response to stimuli linked to their respective field of expertise. It is currently unknown whether similar patterns can be observed with regard to social expertise. The current study therefore focuses on social openness, a central social skill necessary to initiate social contact. Human body odors were used as social cues, as they inherently signal the presence of another human being. Using functional MRI, hemodynamic brain responses to body odors of women reporting a high (n = 14) or a low (n = 12) level of social openness were compared. Greater activation within the inferior frontal gyrus and the caudate nucleus was observed in high socially open individuals compared to individuals low in social openness. With the inferior frontal gyrus being a crucial part of the human mirror neuron system, and the caudate nucleus being implicated in social reward, it is discussed whether human body odor might constitute more of a significant and rewarding social signal to individuals high in social openness compared to individuals low in social openness process.

  11. Oncologic Safety of Laparoscopic Wedge Resection with Gastrotomy for Gastric Gastrointestinal Stromal Tumor: Comparison with Conventional Laparoscopic Wedge Resection

    PubMed Central

    Lee, Sejin; Kim, You Na; Kim, Hyoung-Il; Cheong, Jae-Ho; Hyung, Woo Jin; Noh, Sung Hoon

    2015-01-01

    Purpose Various laparoscopic wedge resection (LWR) techniques requiring gastrotomy for gastrointestinal stromal tumors (GISTs) of the stomach have been applied to facilitate tumor resection and preserve the remnant gastric volume. However, there is the possibility of cancer cell dissemination during these procedures. The aim of this study was to assess the oncologic safety of LWR with gastrotomy (LWR-G) compared to LWR without luminal exposure. Materials and Methods Clinicopathologic and operative results of 193 patients who underwent LWR for gastric GIST were retrospectively analyzed from 2003 to 2013. We stratified the patients into two groups: LWR-G and LWR without gastrotomy (LWR-C). Clinicopathologic features, short-term outcomes, and long-term outcomes were compared. Results A total of 26 patients underwent LWR-G, and 167 patients underwent LWR-C. The LWR-G group showed significantly more anterior wall-located (n=10, 38.5%), intraluminal (n=20, 76.9%), and ulcerative (n=13, 50.0%) tumors than the LWR-C group (n=33, 19.8%; n=96, 57.5%; n=46, 27.5%, respectively). Postoperative short-term outcomes did not differ between the two groups. When tumor staging was compared, no statistical difference was noted. There was no recurrence in the LWR-G group, while 2 patients in the LWR-C group experienced recurrence. The two recurrences in the LWR-C group were found in the liver and in the remnant stomach at 63 and 12 months after the operation, respectively. No gastric GIST-related death was recorded in any group during the study period. Conclusions LWR-G for gastric GIST is an oncologically safe procedure even for masses with ulcerations. PMID:26819802

  12. High-pressure open-channel on-chip electroosmotic pump for nanoflow high performance liquid chromatography.

    PubMed

    Wang, Wei; Gu, Congying; Lynch, Kyle B; Lu, Joann J; Zhang, Zhengyu; Pu, Qiaosheng; Liu, Shaorong

    2014-02-18

    Here, we construct an open-channel on-chip electroosmotic pump capable of generating pressures up to ∼170 bar and flow rates up to ∼500 nL/min, adequate for high performance liquid chromatographic (HPLC) separations. A great feature of this pump is that a number of its basic pump units can be connected in series to enhance its pumping power; the output pressure is directly proportional to the number of pump units connected. This additive nature is excellent and useful, and no other pumps can work in this fashion. We demonstrate the feasibility of using this pump to perform nanoflow HPLC separations; tryptic digests of bovine serum albumin (BSA), transferrin factor (TF), and human immunoglobulins (IgG) are utilized as exemplary samples. We also compare the performance of our electroosmotic (EO)-driven HPLC with Agilent 1200 HPLC; comparable efficiencies, resolutions, and peak capacities are obtained. Since the pump is based on electroosmosis, it has no moving parts. The common material and process also allow this pump to be integrated with other microfabricated functional components. Development of this high-pressure on-chip pump will have a profound impact on the advancement of lab-on-a-chip devices.

  13. High-pressure open-channel on-chip electroosmotic pump for nanoflow high performance liquid chromatography.

    PubMed

    Wang, Wei; Gu, Congying; Lynch, Kyle B; Lu, Joann J; Zhang, Zhengyu; Pu, Qiaosheng; Liu, Shaorong

    2014-02-18

    Here, we construct an open-channel on-chip electroosmotic pump capable of generating pressures up to ∼170 bar and flow rates up to ∼500 nL/min, adequate for high performance liquid chromatographic (HPLC) separations. A great feature of this pump is that a number of its basic pump units can be connected in series to enhance its pumping power; the output pressure is directly proportional to the number of pump units connected. This additive nature is excellent and useful, and no other pumps can work in this fashion. We demonstrate the feasibility of using this pump to perform nanoflow HPLC separations; tryptic digests of bovine serum albumin (BSA), transferrin factor (TF), and human immunoglobulins (IgG) are utilized as exemplary samples. We also compare the performance of our electroosmotic (EO)-driven HPLC with Agilent 1200 HPLC; comparable efficiencies, resolutions, and peak capacities are obtained. Since the pump is based on electroosmosis, it has no moving parts. The common material and process also allow this pump to be integrated with other microfabricated functional components. Development of this high-pressure on-chip pump will have a profound impact on the advancement of lab-on-a-chip devices. PMID:24495233

  14. Closing the wedge: Search strategies for extended Higgs sectors with heavy flavor final states

    NASA Astrophysics Data System (ADS)

    Gori, Stefania; Kim, Ian-Woo; Shah, Nausheen R.; Zurek, Kathryn M.

    2016-04-01

    We consider search strategies for an extended Higgs sector at the high-luminosity LHC14 utilizing multitop final states. In the framework of a two Higgs doublet model, the purely top final states (t t ¯ , 4 t ) are important channels for heavy Higgs bosons with masses in the wedge above 2 mt and at low values of tan β , while a 2 b 2 t final state is most relevant at moderate values of tan β . We find, in the t t ¯H channel, with H →t t ¯, that both single and three lepton final states can provide statistically significant constraints at low values of tan β for mA as high as ˜750 GeV . When systematics on the t t ¯ background are taken into account, however, the three lepton final state is more powerful, though the precise constraint depends fairly sensitively on lepton fake rates. We also find that neither 2 b 2 t nor t t ¯ final states provide constraints on additional heavy Higgs bosons with couplings to tops smaller than the top Yukawa due to expected systematic uncertainties in the t t ¯ background.

  15. Comparison of weak-shock reflection factors for wedges, cylinders and blast waves

    SciTech Connect

    Reichenbach, H.; Kuhl, A.L.

    1992-07-01

    Ernst Mach (1838--1916) was the first to discover an irregular reflection phenomenon of shock waves, as is well known in our community. In fact, this occurred in 1875 -- three years earlier than usually assumed in the literature. A facsimile of the paper in which he mentioned a special shock wave behavior is shown in a figure. However, it is correct that Mach gave the physical interpretation of this phenomenon in 1878. Since Mach`s discovery of an irregular shock reflection pattern 117 years ago, new shock configurations have been discovered -- one of the most recent examples is the so-called {open_quotes}von Neumann reflection{close_quotes} for weak shocks as reported by Colella and Henderson in 1990. Due to active research efforts related to shock reflection, especially in the last two decades, we now have a relatively detailed understanding of reflection phenomena and of transition conditions from one reflection configuration to another. The purpose of this paper is to compare reflection factors for weak shocks from various surfaces, and to focus attention on some unsolved questions. Three different cases are considered: (1) square-wave planar shock reflection from wedges, (2) square-wave planar shock reflection from cylinders and (3) spherical blast wave reflection from a planar surface. The authors restrict themselves to weak shocks. Following Henderson`s definition, shocks with a Mach number of M{sub 0} < 1.56 in air or with an overpressure of {Delta}p{sub I} < 25 psi (1.66 bar) under normal ambient conditions are called weak.

  16. Comparison of weak-shock reflection factors for wedges, cylinders and blast waves

    SciTech Connect

    Reichenbach, H. , Freiburg im Breisgau ); Kuhl, A.L. )

    1992-07-01

    Ernst Mach (1838--1916) was the first to discover an irregular reflection phenomenon of shock waves, as is well known in our community. In fact, this occurred in 1875 -- three years earlier than usually assumed in the literature. A facsimile of the paper in which he mentioned a special shock wave behavior is shown in a figure. However, it is correct that Mach gave the physical interpretation of this phenomenon in 1878. Since Mach's discovery of an irregular shock reflection pattern 117 years ago, new shock configurations have been discovered -- one of the most recent examples is the so-called [open quotes]von Neumann reflection[close quotes] for weak shocks as reported by Colella and Henderson in 1990. Due to active research efforts related to shock reflection, especially in the last two decades, we now have a relatively detailed understanding of reflection phenomena and of transition conditions from one reflection configuration to another. The purpose of this paper is to compare reflection factors for weak shocks from various surfaces, and to focus attention on some unsolved questions. Three different cases are considered: (1) square-wave planar shock reflection from wedges, (2) square-wave planar shock reflection from cylinders and (3) spherical blast wave reflection from a planar surface. The authors restrict themselves to weak shocks. Following Henderson's definition, shocks with a Mach number of M[sub 0] < 1.56 in air or with an overpressure of [Delta]p[sub I] < 25 psi (1.66 bar) under normal ambient conditions are called weak.

  17. High-throughput metagenomic technologies for complex microbial community analysis. Open and closed formats

    DOE PAGESBeta

    Zhou, Jizhong; He, Zhili; Yang, Yunfeng; Deng, Ye; Tringe, Susannah G.; Alvarez-Cohen, Lisa

    2015-01-27

    Understanding the structure, functions, activities and dynamics of microbial communities in natural environments is one of the grand challenges of 21st century science. To address this challenge, over the past decade, numerous technologies have been developed for interrogating microbial communities, of which some are amenable to exploratory work (e.g., high-throughput sequencing and phenotypic screening) and others depend on reference genes or genomes (e.g., phylogenetic and functional gene arrays). Here, we provide a critical review and synthesis of the most commonly applied “open-format” and “closed-format” detection technologies. We discuss their characteristics, advantages, and disadvantages within the context of environmental applications andmore » focus on analysis of complex microbial systems, such as those in soils, in which diversity is high and reference genomes are few. In addition, we discuss crucial issues and considerations associated with applying complementary high-throughput molecular technologies to address important ecological questions.« less

  18. Effect of Laterally Wedged Insoles on the External Knee Adduction Moment across Different Reference Frames

    PubMed Central

    Yamaguchi, Satoshi; Kitamura, Masako; Ushikubo, Tomohiro; Murata, Atsushi; Akagi, Ryuichiro; Sasho, Takahisa

    2015-01-01

    Objective Biomechanical effects of laterally wedged insoles are assessed by reduction in the knee adduction moment. However, the degree of reduction may vary depending on the reference frame with which it is calculated. The purpose of this study was to clarify the effect of reference frame on the reduction in the knee adduction moment by laterally wedged insoles. Methods Twenty-nine healthy participants performed gait trials with a laterally wedged insole and with a flat insole as a control. The knee adduction moment, including the first and second peaks and the angular impulse, were calculated using four different reference frames: the femoral frame, tibial frame, laboratory frame and the Joint Coordinate System. Results There were significant effects of reference frame on the knee adduction moment first and second peaks (P < 0.001 for both variables), while the effect was not significant for the angular impulse (P = 0.84). No significant interaction between the gait condition and reference frame was found in either of the knee adduction moment variables (P = 0.99 for all variables), indicating that the effects of laterally wedged insole on the knee adduction moments were similar across the four reference frames. On the other hand, the average percent changes ranged from 9% to 16% for the first peak, from 16% to 18% for the second peak and from 17% to 21% for the angular impulse when using the different reference frames. Conclusion The effects of laterally wedged insole on the reduction in the knee adduction moment were similar across the reference frames. On the other hand, Researchers need to recognize that when the percent change was used as the parameter of the efficacy of laterally wedged insole, the choice of reference frame may influence the interpretation of how laterally wedged insoles affect the knee adduction moment. PMID:26397375

  19. Collinear spin-density-wave ordering in Fe/Cr multilayers and wedges

    SciTech Connect

    Fishman, R.S.; Shi, Z.

    1999-06-01

    Several recent experiments have detected a spin-density wave (SDW) within the Cr spacer of Fe/Cr multilayers and wedges. We use two simple models to predict the behavior of a collinear SDW within an Fe/Cr/Fe trilayer. Both models combine assumed boundary conditions at the Fe-Cr interfaces with the free energy of the Cr spacer. Depending on the temperature and the number {ital N} of Cr monolayers, the SDW may be either commensurate ({ital C}) or incommensurate ({ital I}) with the bcc Cr lattice. Model I assumes that the Fe-Cr interface is perfect and that the Fe-Cr interaction is antiferromagnetic. Consequently, the {ital I} SDW antinodes lie near the Fe-Cr interfaces. With increasing temperature, the Cr spacer undergoes a series of transitions between {ital I} SDW phases with different numbers {ital n} of nodes. If the {ital I} SDW has n=m nodes at T=0, then {ital n} increases by one at each phase transition from {ital m} to m{minus}1 to m{minus}2 up to the {ital C} phase with n=0 above T{sub IC}(N). For a fixed temperature, the magnetic coupling across the Cr spacer undergoes a phase slip whenever {ital n} changes by one. In the limit N{r_arrow}{infinity}, T{sub IC}(N) is independent of the Fe-Cr coupling strength. We find that T{sub IC}({infinity}) is always larger than the bulk N{acute e}el transition temperature and increases with the strain on the Cr spacer. These results explain the very high IC transition temperature of about 600 K extrapolated from measurements on Fe/Cr/Fe wedges. Model II assumes that the {ital I} SDW nodes lie precisely at the Fe-Cr interfaces. This condition may be enforced by the interfacial roughness of sputtered Fe/Cr multilayers. As a result, the {ital C} phase is never stable and the transition temperature T{sub N}(N) takes on a seesaw pattern as n{ge}2 increases with thickness. In agreement with measurements on both sputtered and epitaxially grown multilayers, model II predicts the {ital I} phase to be unstable above the bulk N

  20. Holocene ice-wedge polygon development in northern Yukon permafrost peatlands (Canada)

    NASA Astrophysics Data System (ADS)

    Fritz, Michael; Wolter, Juliane; Rudaya, Natalia; Palagushkina, Olga; Nazarova, Larisa; Obu, Jaroslav; Rethemeyer, Janet; Lantuit, Hugues; Wetterich, Sebastian

    2016-09-01

    Ice-wedge polygon (IWP) peatlands in the Arctic and Subarctic are extremely vulnerable to climatic and environmental change. We present the results of a multidisciplinary paleoenvironmental study on IWPs in the northern Yukon, Canada. High-resolution laboratory analyses were carried out on a permafrost core and the overlying seasonally thawed (active) layer, from an IWP located in a drained lake basin on Herschel Island. In relation to 14 Accelerator Mass Spectrometry (AMS) radiocarbon dates spanning the last 5000 years, we report sedimentary data including grain size distribution and biogeochemical parameters (organic carbon, nitrogen, C/N ratio, δ13C), stable water isotopes (δ18O, δD), as well as fossil pollen, plant macrofossil and diatom assemblages. Three sediment units (SUs) correspond to the main stages of deposition (1) in a thermokarst lake (SU1: 4950 to 3950 cal yrs BP), (2) during transition from lacustrine to palustrine conditions after lake drainage (SU2: 3950 to 3120 cal yrs BP), and (3) in palustrine conditions of the IWP field that developed after drainage (SU3: 3120 cal yrs BP to 2012 CE). The lacustrine phase (pre 3950 cal yrs BP) is characterized by planktonic-benthic and pioneer diatom species indicating circumneutral waters, and very few plant macrofossils. The pollen record has captured a regional signal of relatively stable vegetation composition and climate for the lacustrine stage of the record until 3950 cal yrs BP. Palustrine conditions with benthic and acidophilic diatom species characterize the peaty shallow-water environments of the low-centered IWP. The transition from lacustrine to palustrine conditions was accompanied by acidification and rapid revegetation of the lake bottom within about 100 years. Since the palustrine phase we consider the pollen record as a local vegetation proxy dominated by the plant communities growing in the IWP. Ice-wedge cracking in water-saturated sediments started immediately after lake drainage at

  1. NeuriteQuant: An open source toolkit for high content screens of neuronal Morphogenesis

    PubMed Central

    2011-01-01

    Background To date, some of the most useful and physiologically relevant neuronal cell culture systems, such as high density co-cultures of astrocytes and primary hippocampal neurons, or differentiated stem cell-derived cultures, are characterized by high cell density and partially overlapping cellular structures. Efficient analytical strategies are required to enable rapid, reliable, quantitative analysis of neuronal morphology in these valuable model systems. Results Here we present the development and validation of a novel bioinformatics pipeline called NeuriteQuant. This tool enables fully automated morphological analysis of large-scale image data from neuronal cultures or brain sections that display a high degree of complexity and overlap of neuronal outgrowths. It also provides an efficient web-based tool to review and evaluate the analysis process. In addition to its built-in functionality, NeuriteQuant can be readily extended based on the rich toolset offered by ImageJ and its associated community of developers. As proof of concept we performed automated screens for modulators of neuronal development in cultures of primary neurons and neuronally differentiated P19 stem cells, which demonstrated specific dose-dependent effects on neuronal morphology. Conclusions NeuriteQuant is a freely available open-source tool for the automated analysis and effective review of large-scale high-content screens. It is especially well suited to quantify the effect of experimental manipulations on physiologically relevant neuronal cultures or brain sections that display a high degree of complexity and overlap among neurites or other cellular structures. PMID:21989414

  2. Versatile wedge-based system for the construction of unidirectional collagen scaffolds by directional freezing: practical and theoretical considerations.

    PubMed

    Pot, Michiel W; Faraj, Kaeuis A; Adawy, Alaa; van Enckevort, Willem J P; van Moerkerk, Herman T B; Vlieg, Elias; Daamen, Willeke F; van Kuppevelt, Toin H

    2015-04-29

    Aligned unidirectional collagen scaffolds may aid regeneration of those tissues where alignment of cells and extracellular matrix is essential, as for instance in cartilage, nerve bundles, and skeletal muscle. Pores can be introduced by ice crystal formation followed by freeze-drying, the pore architecture reflecting the ice crystal morphology. In this study we developed a wedge-based system allowing the production of a wide range of collagen scaffolds with unidirectional pores by directional freezing. Insoluble type I collagen suspensions were frozen using a custom-made wedge system, facilitating the formation of a horizontal as well as a vertical temperature gradient and providing a controlled solidification area for ice dendrites. The system permitted the growth of aligned unidirectional ice crystals over a large distance (>2.5 cm), an insulator prolonging the freezing process and facilitating the construction of crack-free scaffolds. Unidirectional collagen scaffolds with tunable pore sizes and pore morphologies were constructed by varying freezing rates and suspension media. The versatility of the system was indicated by the construction of unidirectional scaffolds from albumin, poly(vinyl alcohol) (a synthetic polymer), and collagen-polymer blends producing hybrid scaffolds. Macroscopic observations, temperature measurements, and scanning electron microscopy indicated that directed horizontal ice dendrite formation, vertical ice crystal nucleation, and evolutionary selection were the basis of the aligned unidirectional ice crystal growth and, hence, the aligned unidirectional pore structure. In conclusion, a simple, highly adjustable freezing system has been developed allowing the construction of large (hybrid) bioscaffolds with tunable unidirectional pore architecture.

  3. A gastrointestinal stromal tumor of the third portion of the duodenum treated by wedge resection: A case report

    PubMed Central

    Acar, Fahrettin; Sahin, Mustafa; Ugras, Serdar; Calisir, Akın

    2013-01-01

    A 65-year old woman was admitted to our hospital with abdominal pain. Computed tomography showed a tumor measuring about 3 cm in diameter with no metastatic lesion or signs of local infiltration. Gastroduodenal endoscopy revealed the presence of a submucosal tumor in the third portion of the duodenum and biopsy revealed tumor cells stained positive for c-kit. These findings were consistent with gastrointestinal stromal tumors (GISTs) and we performed a wedge resection of the duodenum, sparing the pancreas. The postoperative course was uneventful and she was discharged on day 6. Surgical margins were negative. Histology revealed a GIST with a diameter of 3.2 cm and < 5 mitoses/50 high power fields, indicating a low risk of malignancy. Therefore, adjuvant therapy with imatinib was not initiated. Wedge resection with primary closure is a surgical procedure that can be used to treat low malignant potential neoplasms of the duodenum and avoid extensive surgery, with significant morbidity and possible mortality, such as pancreatoduodenectomy. PMID:24392185

  4. Falkner-Skan flow of a magnetic-Carreau fluid past a wedge in the presence of cross diffusion effects

    NASA Astrophysics Data System (ADS)

    Raju, C. S. K.; Sandeep, N.

    2016-08-01

    Heat and mass transfer in the Falkner-Skan flow of a Carreau fluid past a wedge is investigated numerically. In most of the existing studies thermal radiation is linear. Due to the prominent importance of the various industrial applications, in this study we considered the nonlinear thermal radiation along with cross diffusion effects for the heat and mass transfer controlling process. Numerical results are presented graphically as well as in tabular form by enforcing Runge-Kutta and Newton's methods. We also validated the present results by comparing with the published results and found favourable agreement. We presented solutions for the flow separation, decelerating and accelerating cases. We observed that the thermal and concentration boundary layers are non-uniform for the flow separation, decelerating and accelerating cases. For industrial needs, we analysed the heat and mass transfer rates of the accelerating, decelerating and flow separation cases and found that the heat transfer rate is high in the accelerating case when compared with the decelerating case. From this we can conclude that the decelerating flow over a wedge is very useful for cooling applications.

  5. Laser-based linear and nonlinear guided elastic waves at surfaces (2D) and wedges (1D).

    PubMed

    Hess, Peter; Lomonosov, Alexey M; Mayer, Andreas P

    2014-01-01

    The characteristic features and applications of linear and nonlinear guided elastic waves propagating along surfaces (2D) and wedges (1D) are discussed. Laser-based excitation, detection, or contact-free analysis of these guided waves with pump-probe methods are reviewed. Determination of material parameters by broadband surface acoustic waves (SAWs) and other applications in nondestructive evaluation (NDE) are considered. The realization of nonlinear SAWs in the form of solitary waves and as shock waves, used for the determination of the fracture strength, is described. The unique properties of dispersion-free wedge waves (WWs) propagating along homogeneous wedges and of dispersive wedge waves observed in the presence of wedge modifications such as tip truncation or coatings are outlined. Theoretical and experimental results on nonlinear wedge waves in isotropic and anisotropic solids are presented.

  6. CCD Washington photometry of three highly field star contaminated open clusters in the third Galactic quadrant

    NASA Astrophysics Data System (ADS)

    Piatti, A. E.; Clariá, J. J.; Parisi, M. C.; Ahumada, A. V.

    2009-01-01

    We present CCD photometry in the Washington system C and T1 passbands down to T1 ˜ 19.5 magnitudes in the fields of Czernik 26, Czernik 30, and Haffner 11, three poorly studied open clusters located in the third Galactic quadrant. We measured T1 magnitudes and C - T1 colors for a total of 6472 stars distributed throughout cluster areas of 13.6' × 13.6' each. Cluster radii were estimated from star counts in appropriate-sized boxes distributed throughout the entire observed fields. Based on the best fits of isochrones computed by the Padova group to the ( C - T1, T1) color-magnitude diagrams (CMDs), we derived color excesses, heliocentric distances and ages for the three clusters. These are characterized by a relatively small angular size and by a high field star contamination. We performed a firm analysis of the field star contamination of the CMDs and examined different relationships between the position in the Galaxy of known open clusters located within 1 kpc around the three studied ones, their age and their interstellar visual absorption. We confirm previous results in the sense that the closer the cluster birthplace to the Galactic plane, the higher the interstellar visual absorption. We also found that the space velocity dispersion perpendicular to the Galactic plane diminishes as the clusters are younger. The positions, interstellar visual absorptions, ages, and metallicities of the three studied clusters favor the hypothesis that they were not born in the recently discovered Canis major (CMa) dwarf galaxy before it was accreted by the Milky Way.

  7. Nonsurgical treatment of adult open bite using edgewise appliance combined with high-pull headgear and class III elastics.

    PubMed

    Saito, Isao; Yamaki, Masaki; Hanada, Kooji

    2005-03-01

    This case report describes the effect of a combination of high-pull headgear and Class III elastics on the nonsurgical treatment of an adult open bite. The 19-year 1-month-old Japanese female presented with the anterior open bite of 4.0 mm and mild crowding. She had a skeletal Class II but a Class III molar relationship due to a severe proclination of the mandibular dental arch. Unilateral congenital missing premolars caused a discrepancy between the facial and dental midline. After extraction of two premolars and the impacted mandibular third molars, nonsurgical therapy was performed using the standard edgewise appliance combined with a high-pull headgear and Class III elastics. The successful treatment outcome and stability of the final occlusion indicates that a combination of high-pull headgear and Class III elastics is one of the effective devices in the nonsurgical treatment of open bite and, is especially helpful in uprighting the mandibular dental arch.

  8. Correlates of Marijuana Drugged Driving and Openness to Driving While High: Evidence from Colorado and Washington

    PubMed Central

    Davis, Kevin C.; Allen, Jane; Duke, Jennifer; Nonnemaker, James; Bradfield, Brian; Farrelly, Matthew C.; Shafer, Paul; Novak, Scott

    2016-01-01

    associated with lower odds of each of these outcomes (OR = 0.63, P < 0.01, OR = 0.69, P = 0.02, respectively). Post-estimation Wald tests confirmed the negative associations with marijuana DUI were greater in magnitude for safety perceptions than knowledge of DUI laws. Increased perceptions that driving while high is unsafe was associated with significantly lower willingness to drive after using marijuana while increased knowledge of marijuana DUI laws was not associated with these outcomes. Conclusions Despite recent interventions targeting public awareness of the legal consequences of marijuana DUI, our results suggest that knowledge of these laws is a weaker predictor of DUI behavior than perceptions that driving high is unsafe. In addition, safety perceptions predict decreased openness to driving high while knowledge of DUI laws was not associated with openness. These findings suggest that interventions for reducing the incidence of marijuana DUI are likely to be more successful by targeting safety perceptions related to marijuana DUI rather than knowledge of DUI laws. We caution that because these data are limited to an online convenience sample, results may not be generalizable beyond our sample. PMID:26800209

  9. New Compound Sets Identified from High Throughput Phenotypic Screening Against Three Kinetoplastid Parasites: An Open Resource

    PubMed Central

    Peña, Imanol; Pilar Manzano, M.; Cantizani, Juan; Kessler, Albane; Alonso-Padilla, Julio; Bardera, Ana I.; Alvarez, Emilio; Colmenarejo, Gonzalo; Cotillo, Ignacio; Roquero, Irene; de Dios-Anton, Francisco; Barroso, Vanessa; Rodriguez, Ana; Gray, David W.; Navarro, Miguel; Kumar, Vinod; Sherstnev, Alexander; Drewry, David H.; Brown, James R.; Fiandor, Jose M.; Julio Martin, J.

    2015-01-01

    Using whole-cell phenotypic assays, the GlaxoSmithKline high-throughput screening (HTS) diversity set of 1.8 million compounds was screened against the three kinetoplastids most relevant to human disease, i.e. Leishmania donovani, Trypanosoma cruzi and Trypanosoma brucei. Secondary confirmatory and orthogonal intracellular anti-parasiticidal assays were conducted, and the potential for non-specific cytotoxicity determined. Hit compounds were chemically clustered and triaged for desirable physicochemical properties. The hypothetical biological target space covered by these diversity sets was investigated through bioinformatics methodologies. Consequently, three anti-kinetoplastid chemical boxes of ~200 compounds each were assembled. Functional analyses of these compounds suggest a wide array of potential modes of action against kinetoplastid kinases, proteases and cytochromes as well as potential host–pathogen targets. This is the first published parallel high throughput screening of a pharma compound collection against kinetoplastids. The compound sets are provided as an open resource for future lead discovery programs, and to address important research questions. PMID:25740547

  10. The Open Connectome Project Data Cluster: Scalable Analysis and Vision for High-Throughput Neuroscience.

    PubMed

    Burns, Randal; Roncal, William Gray; Kleissas, Dean; Lillaney, Kunal; Manavalan, Priya; Perlman, Eric; Berger, Daniel R; Bock, Davi D; Chung, Kwanghun; Grosenick, Logan; Kasthuri, Narayanan; Weiler, Nicholas C; Deisseroth, Karl; Kazhdan, Michael; Lichtman, Jeff; Reid, R Clay; Smith, Stephen J; Szalay, Alexander S; Vogelstein, Joshua T; Vogelstein, R Jacob

    2013-01-01

    We describe a scalable database cluster for the spatial analysis and annotation of high-throughput brain imaging data, initially for 3-d electron microscopy image stacks, but for time-series and multi-channel data as well. The system was designed primarily for workloads that build connectomes- neural connectivity maps of the brain-using the parallel execution of computer vision algorithms on high-performance compute clusters. These services and open-science data sets are publicly available at openconnecto.me. The system design inherits much from NoSQL scale-out and data-intensive computing architectures. We distribute data to cluster nodes by partitioning a spatial index. We direct I/O to different systems-reads to parallel disk arrays and writes to solid-state storage-to avoid I/O interference and maximize throughput. All programming interfaces are RESTful Web services, which are simple and stateless, improving scalability and usability. We include a performance evaluation of the production system, highlighting the effec-tiveness of spatial data organization.

  11. Dynamic simulation and safety evaluation of high-speed trains meeting in open air

    NASA Astrophysics Data System (ADS)

    Li, Songyan; Zheng, Zhijun; Yu, Jilin; Qian, Chunqiang

    2016-04-01

    Dynamic responses of a carriage under excitation with the German high-speed low-interference track spectrum together with the air pressure pulse generated as high-speed trains passing each other are investigated with a multi-body dynamics method. The variations of degrees of freedom (DOFs: horizontal movement, roll angle, and yaw angle), the lateral wheel-rail force, the derailment coefficient, and the rate of wheel load reduction with time when two carriages meet in open air are obtained and compared with the results of a single train travelling at specified speeds. Results show that the rate of wheel load reduction increases with the increase of train speed and meets some safety standard at a certain speed, but exceeding the value of the rate of wheel load reduction does not necessarily mean derailment. The evaluation standard of the rate of wheel load reduction is somewhat conservative and may be loosened. The pressure pulse has significant effects on the train DOFs, and the evaluations of these safety indexes are strongly suggested in practice. The pressure pulse has a limited effect on the derailment coefficient and the lateral wheel-rail force, and, thus, their further evaluations may be not necessary.

  12. Achieving Energy Savings with Highly-Controlled Lighting in an Open-Plan Office

    SciTech Connect

    Rubinstein, Francis; Enscoe, Abby

    2010-04-19

    An installation in a Federal building tested the effectiveness of a highly-controlled, workstation-specific lighting retrofit. The study took place in an open-office area with 86 cubicles and low levels of daylight. Each cubicle was illuminated by a direct/indirectpendant luminaire with three 32 watt lamps, two dimmable DALI ballasts, and an occupancy sensor. A centralized control system programmed all three lamps to turn on and off according to occupancy on a workstation-by-workstation basis. Field measurements taken over the course of several monthsdemonstrated 40% lighting energy savings compared to a baseline without advanced controls that conforms to GSA's current retrofit standard. A photometric analysis found that the installation provided higher desktop light levels than the baseline, while an occupant survey found that occupants in general preferred the lighting system to thebaseline.Simple payback is fairly high; projects that can achieve lower installation costs and/or higher energy savings and those in which greenhouse gas reduction and occupant satisfaction are significant priorities provide the ideal setting for workstation-specific lighting retrofits.

  13. The Open Connectome Project Data Cluster: Scalable Analysis and Vision for High-Throughput Neuroscience.

    PubMed

    Burns, Randal; Roncal, William Gray; Kleissas, Dean; Lillaney, Kunal; Manavalan, Priya; Perlman, Eric; Berger, Daniel R; Bock, Davi D; Chung, Kwanghun; Grosenick, Logan; Kasthuri, Narayanan; Weiler, Nicholas C; Deisseroth, Karl; Kazhdan, Michael; Lichtman, Jeff; Reid, R Clay; Smith, Stephen J; Szalay, Alexander S; Vogelstein, Joshua T; Vogelstein, R Jacob

    2013-01-01

    We describe a scalable database cluster for the spatial analysis and annotation of high-throughput brain imaging data, initially for 3-d electron microscopy image stacks, but for time-series and multi-channel data as well. The system was designed primarily for workloads that build connectomes- neural connectivity maps of the brain-using the parallel execution of computer vision algorithms on high-performance compute clusters. These services and open-science data sets are publicly available at openconnecto.me. The system design inherits much from NoSQL scale-out and data-intensive computing architectures. We distribute data to cluster nodes by partitioning a spatial index. We direct I/O to different systems-reads to parallel disk arrays and writes to solid-state storage-to avoid I/O interference and maximize throughput. All programming interfaces are RESTful Web services, which are simple and stateless, improving scalability and usability. We include a performance evaluation of the production system, highlighting the effec-tiveness of spatial data organization. PMID:24401992

  14. The Open Connectome Project Data Cluster: Scalable Analysis and Vision for High-Throughput Neuroscience

    PubMed Central

    Burns, Randal; Roncal, William Gray; Kleissas, Dean; Lillaney, Kunal; Manavalan, Priya; Perlman, Eric; Berger, Daniel R.; Bock, Davi D.; Chung, Kwanghun; Grosenick, Logan; Kasthuri, Narayanan; Weiler, Nicholas C.; Deisseroth, Karl; Kazhdan, Michael; Lichtman, Jeff; Reid, R. Clay; Smith, Stephen J.; Szalay, Alexander S.; Vogelstein, Joshua T.; Vogelstein, R. Jacob

    2013-01-01

    We describe a scalable database cluster for the spatial analysis and annotation of high-throughput brain imaging data, initially for 3-d electron microscopy image stacks, but for time-series and multi-channel data as well. The system was designed primarily for workloads that build connectomes— neural connectivity maps of the brain—using the parallel execution of computer vision algorithms on high-performance compute clusters. These services and open-science data sets are publicly available at openconnecto.me. The system design inherits much from NoSQL scale-out and data-intensive computing architectures. We distribute data to cluster nodes by partitioning a spatial index. We direct I/O to different systems—reads to parallel disk arrays and writes to solid-state storage—to avoid I/O interference and maximize throughput. All programming interfaces are RESTful Web services, which are simple and stateless, improving scalability and usability. We include a performance evaluation of the production system, highlighting the effec-tiveness of spatial data organization. PMID:24401992

  15. Self-induced gaseous plasma as high power microwave opening switch medium

    SciTech Connect

    Lin, S.; Beeson, S.; Dickens, J.; Neuber, A.; Liu, C.

    2015-04-15

    Self-induced gaseous plasma is evaluated as active opening switch medium for pulsed high power microwave radiation. The self-induced plasma switch is investigated for N{sub 2} and Ar environments under pressure conditions ranging from 25 to 700 Torr. A multi-pass TE{sub 111} resonator is used to significantly reduce the delay time inherently associated with plasma generation. The plasma forms under the pulsed excitation of a 4 MW magnetron inside the central dielectric tube of the resonator, which isolates the inner atmospheric gas from the outer vacuum environment. The path from the power source to the load is designed such that the pulse passes through the plasma twice with a 35 ns delay between these two passes. In the first pass, initial plasma density is generated, while the second affects the transition to a highly reflective state with as much as 30 dB attenuation. Experimental data revealed that virtually zero delay time may be achieved for N{sub 2} at 25 Torr. A two-dimensional fluid model was developed to study the plasma formation times for comparison with experimental data. The delay time predicted from this model agrees well with the experimental values in the lower pressure regime (error < 25%), however, due to filamentary plasma formation at higher pressures, simulated delay times may be underestimated by as much as 50%.

  16. Characterizing and configuring motorized wedge for a new generation telecobalt machine in a treatment planning system.

    PubMed

    Kinhikar, Rajesh A; Sharma, Smriti; Upreti, Rituraj; Tambe, Chandrashekhar M; Deshpande, Deepak D

    2007-01-01

    A new generation telecobalt unit, Theratron Equinox-80, (MDS Nordion, Canada) has been evaluated. It is equipped with a single 60-degree motorized wedge (MW), four universal wedges (UW) for 15°, 30°, 45° and 60°. MW was configured in Eclipse (Varian, Palo Alto, USA) 3D treatment planning system (TPS). The profiles and central axis depth doses (CADD) were measured with radiation field analyzer blue water phantom for MW. These profiles and CADD for MW were compared with UW in a homogeneous phantom generated in Eclipse for various field sizes. The absolute dose was measured for a field size of 10 × 10 cm2 only in a MEDTEC water phantom at 10 cm depth with a 0.13 cc thimble ion chamber (Scanditronix Wellhofer, Uppsala, Sweden) and a NE electrometer (Nuclear Enterprises, UK). Measured dose with ion chamber was compared with the TPS predicted dose. MW angle was verified on the Equinox for four angles (15°, 30°, 45° and 60°). The variation in measured and calculated dose at 10 cm depth was within 2%. The measured and the calculated wedge angles were in well agreement within 2°. The motorized wedges were successfully configured in Eclipse for four wedge angles. PMID:21217916

  17. Wedge and spring assembly for securing coils in electromagnets and dynamoelectric machines

    DOEpatents

    Lindner, M.; Cottingham, J.G.

    1996-03-12

    A wedge and spring assembly for use in electromagnets or dynamoelectric machines is disclosed having a housing with an axis therethrough and a plurality of coils supported on salient poles that extend radially inward from the housing toward the housing axis to define a plurality of interpole spaces. The wedge and spring assembly includes a nonmagnetic retainer spring and a nonmagnetic wedge. The retainer spring is formed to fit into one of the interpole spaces, and has juxtaposed ends defining between them a slit extending in a direction generally parallel to the housing axis. The wedge for insertion into the slit provides an outwardly directed force on respective portions of the juxtaposed ends to expand the slit so that respective portions of the retainer spring engage areas of the coils adjacent thereto, thereby resiliently holding the coils against their respective salient poles. The retainer spring is generally triangular shaped to fit within the interpole space, and the wedge is generally T-shaped. 6 figs.

  18. Parental arc magma compositions dominantly controlled by mantle-wedge thermal structure

    NASA Astrophysics Data System (ADS)

    Turner, Stephen J.; Langmuir, Charles H.; Katz, Richard F.; Dungan, Michael A.; Escrig, Stéphane

    2016-10-01

    The processes that lead to the fourfold variation in arc-averaged compositions of mafic arc lavas remain controversial. Control by the mantle-wedge thermal structure is supported by chemical correlations with the thickness of the underlying arc crust, which affects the thermal state of the wedge. Control by down-going slab temperature is supported by correlations with the slab thermal parameter. The Chilean Southern Volcanic Zone provides a test of these hypotheses. Here we use chemical data to demonstrate that the Southern Volcanic Zone and global arc averages define the same chemical trends, both among elements and between elements and crustal thickness. But in contrast to the global arc system, the Southern Volcanic Zone is built on crust of variable thickness with a constant slab thermal parameter. This natural experiment, along with a set of numerical simulations, shows that global arc compositional variability is dominated by different extents of melting that are controlled by the thermal structure of the mantle wedge. Slab temperatures play a subordinate role. Variations in the subducting slab's fluid flux and sediment compositions, as well as mantle-wedge heterogeneities, produce second-order effects that are manifested as distinctive trace element and isotopic signatures; these can be more clearly elucidated once the importance of wedge thermal structure is recognized.

  19. Interaction of disturbances with an oblique detonation wave attached to a wedge

    NASA Technical Reports Server (NTRS)

    Lasseigne, D. G.; Hussaini, M. Y.

    1992-01-01

    The linear response of an oblique overdriven detonation to impose free stream disturbances or to periodic movements of the wedge is examined. The free stream disturbances are assumed to be steady vorticity waves and the wedge motions are considered to be time periodic oscillations either about a fixed pivot point or along the plane of symmetry of the wedge aligned with the incoming stream. The detonation is considered to be a region of infinitesmal thickness in which a finite amount of heat is released. The response to the imposed disturbances is a function of the Mach number of the incoming flow, the wedge angle, and the exothermocity of the reaction within the detonation. It is shown that as the degree of overdrive increases, the amplitude of the response increases significantly; furthermore, a fundamental difference in the dependence of the response on the parameters of the problem is found between the response to a free stream disturbance and to a disturbance emanating from the wedge surface.

  20. Medpor Craniotomy Gap Wedge Designed to Fill Small Bone Defects along Cranial Bone Flap

    PubMed Central

    Goh, Duck-Ho; Kim, Gyoung-Ju

    2009-01-01

    Objective Medpor porous polyethylene was used to reconstruct small bone defects (gaps and burr holes) along a craniotomy bone flap. The feasibility and cosmetic results were evaluated. Methods Medpor Craniotomy Gap Wedges, V and T, were designed. The V implant is a 10 cm-long wedge strip, the cross section of which is an isosceles triangle with a 4 mm-long base, making it suitable for gaps less than 4 mm after trimming. Meanwhile, the Medpor T wedge includes a 10 mm-wide thin plate on the top surface of the Medpor V Wedge, making it suitable for gaps wider than 4 mm and burr holes. Sixty-eight pterional craniotomies and 39 superciliary approaches were performed using the implants, and the operative results were evaluated with respect to the cosmetic results and pain or tenderness related to the cranial flap. Results The small bone defects were eliminated with less than 10 minutes additional operative time. In a physical examination, there were no considerable cosmetic problems regarding to the cranial bone defects, such as a linear depression or dimple in the forehead, anterior temporal hollow, preauricular depression, and parietal burr hole defect. Plus, no patient suffered from any infectious complications. Conclusion The Medpor Craniotomy Gap Wedge is technically easy to work with for reconstructing small bone defects, such as the bone gaps and burr holes created by a craniotomy, and produces excellent cosmetic results. PMID:19844617

  1. Determination of the pulmonary capillary wedge position in patients with giant left atrial V waves.

    PubMed

    Moore, R A; Neary, M J; Gallagher, J D; Clark, D L

    1987-04-01

    Thirteen patients with giant left atrial V waves during preoperative cardiac catheterization were admitted into the study group. While awake and breathing spontaneously, simultaneous recordings of electrocardiographic leads II and V5, radial arterial traces, and pulmonary arterial or pulmonary capillary wedge traces were obtained. Measurements were made on four consecutive cardiac cycles in the unwedged and wedged positions for the following intervals: Q wave to the radial arterial upstroke (220 +/- 20 milliseconds) and peak (360 +/- 10 milliseconds), Q wave to the pulmonary arterial upstroke (170 +/- 20 milliseconds) and peak (350 +/- 20 milliseconds), Q wave to the V wave upstroke (280 +/- 20 milliseconds) and peak (570 +/- 20 milliseconds), and QT interval (420 +/- 20 milliseconds). These findings indicate that the radial arterial and pulmonary arterial upstrokes and peaks occur nearly simultaneously. Upon wedging, the V wave upstroke occurs significantly later in the cardiac cycle (P less than .05) compared with the pulmonary arterial upstroke, and the V wave peak occurs significantly later compared with both the pulmonary arterial and the radial arterial peak (P less than .05). A rapid, simple beat-to-beat method for differentiating pulmonary arterial from pulmonary capillary wedge positions in the presence of giant left atrial V waves is the superimposition of the pulmonary arterial trace on the radial arterial trace. When a wedge position is attained, there is an immediate rightward shift in the upstroke and peak of the pulmonary arterial pressure trace, which can be easily identified by observing the relationship between the pulmonary arterial and systemic arterial traces.

  2. Ultrasonographic Identification of Fibromuscular Bands Associated with Neurogenic Thoracic Outlet Syndrome: The "Wedge-Sickle" Sign.

    PubMed

    Arányi, Zsuzsanna; Csillik, Anita; Böhm, Josef; Schelle, Thomas

    2016-10-01

    Thoracic outlet syndrome (TOS) is a disorder characterized by compression of the lower trunk of the brachial plexus, most often in association with anomalous congenital fibromuscular bands in the scalenic region. Early diagnosis is important, because the neurologic deficit associated with TOS may be irreversible. Using high-resolution ultrasound, we investigated 20 consecutive patients with clinical signs suggestive of TOS (all females, average age: 40.4 ± 14.9 y) and 25 control patients. In 19 patients, we identified a hyper-echoic fibromuscular structure at the medial edge of the middle scalene muscle, which indented the lower trunk of the brachial plexus ("wedge-sickle sign"). It was associated with the significant enlargement (p < 0.0001) and hypo-echogenicity of the lower trunk. This novel and distinctive ultrasonographic sign allows pre-surgical identification of anomalous fibromuscular bands causing TOS. It is especially useful in patients without neurologic deficit, in whom the diagnosis may not be as straightforward. PMID:27444863

  3. Hospital-wide rollout of antimicrobial stewardship: a stepped-wedge randomized trial.

    PubMed

    Palmay, Lesley; Elligsen, Marion; Walker, Sandra A N; Pinto, Ruxandra; Walker, Scott; Einarson, Thomas; Simor, Andrew; Rachlis, Anita; Mubareka, Samira; Daneman, Nick

    2014-09-15

    Our objective was to rigorously evaluate the impact of an antimicrobial stewardship audit-and-feedback intervention, via a stepped-wedge randomized trial. An effective intensive care unit (ICU) audit-and-feedback program was rolled out to 6 non-ICU services in a randomized sequence. The primary outcome was targeted antimicrobial utilization, using a negative binomial regression model to assess the impact of the intervention while accounting for secular and seasonal trends. The intervention was successfully transitioned, with high volumes of orders reviewed, suggestions made, and recommendations accepted. Among patients meeting stewardship review criteria, the intervention was associated with a large reduction in targeted antimicrobial utilization (-21%, P = .004); however, there was no significant change in targeted antibiotic use among all admitted patients (-1.2%, P = .9), and no reductions in overall costs and microbiologic outcomes. An ICU day 3 audit-and-feedback program can be successfully expanded hospital-wide, but broader benefits on non-ICU wards may require interventions earlier in the course of treatment.

  4. Global typology of urban energy use and potentials for an urbanization mitigation wedge

    PubMed Central

    Creutzig, Felix; Baiocchi, Giovanni; Bierkandt, Robert; Pichler, Peter-Paul; Seto, Karen C.

    2015-01-01

    The aggregate potential for urban mitigation of global climate change is insufficiently understood. Our analysis, using a dataset of 274 cities representing all city sizes and regions worldwide, demonstrates that economic activity, transport costs, geographic factors, and urban form explain 37% of urban direct energy use and 88% of urban transport energy use. If current trends in urban expansion continue, urban energy use will increase more than threefold, from 240 EJ in 2005 to 730 EJ in 2050. Our model shows that urban planning and transport policies can limit the future increase in urban energy use to 540 EJ in 2050 and contribute to mitigating climate change. However, effective policies for reducing urban greenhouse gas emissions differ with city type. The results show that, for affluent and mature cities, higher gasoline prices combined with compact urban form can result in savings in both residential and transport energy use. In contrast, for developing-country cities with emerging or nascent infrastructures, compact urban form, and transport planning can encourage higher population densities and subsequently avoid lock-in of high carbon emission patterns for travel. The results underscore a significant potential urbanization wedge for reducing energy use in rapidly urbanizing Asia, Africa, and the Middle East. PMID:25583508

  5. Seismic evidence for flow in the hydrated mantle wedge of the Ryukyu subduction zone

    NASA Astrophysics Data System (ADS)

    Nagaya, Takayoshi; Walker, Andrew M.; Wookey, James; Wallis, Simon R.; Ishii, Kazuhiko; Kendall, J.-Michael

    2016-07-01

    It is widely accepted that water-rich serpentinite domains are commonly present in the mantle above shallow subducting slabs and play key roles in controlling the geochemical cycling and physical properties of subduction zones. Thermal and petrological models show the dominant serpentine mineral is antigorite. However, there is no good consensus on the amount, distribution and alignment of this mineral. Seismic velocities are commonly used to identify antigorite-rich domains, but antigorite is highly-anisotropic and depending on the seismic ray path, its properties can be very difficult to distinguish from non-hydrated olivine-rich mantle. Here, we utilize this anisotropy and show how an analysis of seismic anisotropy that incorporates measured ray path geometries in the Ryukyu arc can constrain the distribution, orientation and amount of antigorite. We find more than 54% of the wedge must consist of antigorite and the alignment must change from vertically aligned to parallel to the slab. This orientation change suggests convective flow in the hydrated forearc mantle. Shear wave splitting analysis in other subduction zones indicates large-scale serpentinization and forearc mantle convection are likely to be more widespread than generally recognized. The view that the forearc mantle of cold subduction zones is dry needs to be reassessed.

  6. Database of Inlet and Exhaust Noise Shielding for Wedge-Shaped Airframe

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.; Clark, Lorenzo R.

    2001-01-01

    An experiment to measure the noise shielding of the blended wing body design concept was developed using a simplified wedge-shaped airframe. The experimental study was conducted in the Langley Anechoic Noise Research Facility. A wideband, omnidirective sound source in a simulated engine nacelle was held at locations representative of a range of engine locations above the wing. The sound field around the model was measured with the airframe and source in place and with source alone, using an-array of microphones on a rotating hoop that is also translated along an axis parallel to the airframe axis. The insertion loss was determined from the difference between the two resulting contours. Although no attempt was made to simulate the noise characteristics of a particular engine, the broadband noise source radiated sound over a range of scaled frequencies encompassing 1 and 2 times the blade passage frequency representative of a large, high-bypass-ratio turbofan engine. The measured data show that significant shielding of the inlet-radiated noise is obtained in the area beneath and upstream of the model. The data show the sensitivity of insertion loss to engine location.

  7. Hospital-wide rollout of antimicrobial stewardship: a stepped-wedge randomized trial.

    PubMed

    Palmay, Lesley; Elligsen, Marion; Walker, Sandra A N; Pinto, Ruxandra; Walker, Scott; Einarson, Thomas; Simor, Andrew; Rachlis, Anita; Mubareka, Samira; Daneman, Nick

    2014-09-15

    Our objective was to rigorously evaluate the impact of an antimicrobial stewardship audit-and-feedback intervention, via a stepped-wedge randomized trial. An effective intensive care unit (ICU) audit-and-feedback program was rolled out to 6 non-ICU services in a randomized sequence. The primary outcome was targeted antimicrobial utilization, using a negative binomial regression model to assess the impact of the intervention while accounting for secular and seasonal trends. The intervention was successfully transitioned, with high volumes of orders reviewed, suggestions made, and recommendations accepted. Among patients meeting stewardship review criteria, the intervention was associated with a large reduction in targeted antimicrobial utilization (-21%, P = .004); however, there was no significant change in targeted antibiotic use among all admitted patients (-1.2%, P = .9), and no reductions in overall costs and microbiologic outcomes. An ICU day 3 audit-and-feedback program can be successfully expanded hospital-wide, but broader benefits on non-ICU wards may require interventions earlier in the course of treatment. PMID:24928294

  8. Seismic evidence for flow in the hydrated mantle wedge of the Ryukyu subduction zone.

    PubMed

    Nagaya, Takayoshi; Walker, Andrew M; Wookey, James; Wallis, Simon R; Ishii, Kazuhiko; Kendall, J-Michael

    2016-01-01

    It is widely accepted that water-rich serpentinite domains are commonly present in the mantle above shallow subducting slabs and play key roles in controlling the geochemical cycling and physical properties of subduction zones. Thermal and petrological models show the dominant serpentine mineral is antigorite. However, there is no good consensus on the amount, distribution and alignment of this mineral. Seismic velocities are commonly used to identify antigorite-rich domains, but antigorite is highly-anisotropic and depending on the seismic ray path, its properties can be very difficult to distinguish from non-hydrated olivine-rich mantle. Here, we utilize this anisotropy and show how an analysis of seismic anisotropy that incorporates measured ray path geometries in the Ryukyu arc can constrain the distribution, orientation and amount of antigorite. We find more than 54% of the wedge must consist of antigorite and the alignment must change from vertically aligned to parallel to the slab. This orientation change suggests convective flow in the hydrated forearc mantle. Shear wave splitting analysis in other subduction zones indicates large-scale serpentinization and forearc mantle convection are likely to be more widespread than generally recognized. The view that the forearc mantle of cold subduction zones is dry needs to be reassessed. PMID:27436676

  9. Seismic evidence for flow in the hydrated mantle wedge of the Ryukyu subduction zone

    PubMed Central

    Nagaya, Takayoshi; Walker, Andrew M.; Wookey, James; Wallis, Simon R.; Ishii, Kazuhiko; Kendall, J. -Michael

    2016-01-01

    It is widely accepted that water-rich serpentinite domains are commonly present in the mantle above shallow subducting slabs and play key roles in controlling the geochemical cycling and physical properties of subduction zones. Thermal and petrological models show the dominant serpentine mineral is antigorite. However, there is no good consensus on the amount, distribution and alignment of this mineral. Seismic velocities are commonly used to identify antigorite-rich domains, but antigorite is highly-anisotropic and depending on the seismic ray path, its properties can be very difficult to distinguish from non-hydrated olivine-rich mantle. Here, we utilize this anisotropy and show how an analysis of seismic anisotropy that incorporates measured ray path geometries in the Ryukyu arc can constrain the distribution, orientation and amount of antigorite. We find more than 54% of the wedge must consist of antigorite and the alignment must change from vertically aligned to parallel to the slab. This orientation change suggests convective flow in the hydrated forearc mantle. Shear wave splitting analysis in other subduction zones indicates large-scale serpentinization and forearc mantle convection are likely to be more widespread than generally recognized. The view that the forearc mantle of cold subduction zones is dry needs to be reassessed. PMID:27436676

  10. Seismic evidence for flow in the hydrated mantle wedge of the Ryukyu subduction zone.

    PubMed

    Nagaya, Takayoshi; Walker, Andrew M; Wookey, James; Wallis, Simon R; Ishii, Kazuhiko; Kendall, J-Michael

    2016-07-20

    It is widely accepted that water-rich serpentinite domains are commonly present in the mantle above shallow subducting slabs and play key roles in controlling the geochemical cycling and physical properties of subduction zones. Thermal and petrological models show the dominant serpentine mineral is antigorite. However, there is no good consensus on the amount, distribution and alignment of this mineral. Seismic velocities are commonly used to identify antigorite-rich domains, but antigorite is highly-anisotropic and depending on the seismic ray path, its properties can be very difficult to distinguish from non-hydrated olivine-rich mantle. Here, we utilize this anisotropy and show how an analysis of seismic anisotropy that incorporates measured ray path geometries in the Ryukyu arc can constrain the distribution, orientation and amount of antigorite. We find more than 54% of the wedge must consist of antigorite and the alignment must change from vertically aligned to parallel to the slab. This orientation change suggests convective flow in the hydrated forearc mantle. Shear wave splitting analysis in other subduction zones indicates large-scale serpentinization and forearc mantle convection are likely to be more widespread than generally recognized. The view that the forearc mantle of cold subduction zones is dry needs to be reassessed.

  11. Structure, variability, and salt flux in a strongly forced salt wedge estuary

    NASA Astrophysics Data System (ADS)

    Ralston, David K.; Geyer, W. Rockwell; Lerczak, James A.

    2010-06-01

    The tidally varying circulation, stratification, and salt flux mechanisms are investigated in a shallow salt wedge estuary where fluvial and tidal velocities are large and the steady baroclinic circulation is comparatively weak. The study integrates field observations and numerical simulations of the Merrimack River estuary. At moderate to high discharge the estuary is short and highly stratified, while at lower discharges it shifts to a longer, more weakly stratified estuary; the transition occurs when the length of the salinity intrusion is similar to the tidal excursion. The Merrimack is highly variable at tidal time scales owing to the advection and mixing of a bottom salinity front. Salt flux is predominantly due to tidal processes rather than steady baroclinic or bathymetric shear. Tidal pumping is important near the mouth, but inside the estuary salt flux is due to tidal asymmetries in the elevation and thickness of the halocline that depend on the tidal amplitude and river discharge. Conditions in the Merrimack, including the salinity intrusion length and stratification, vary more with event to seasonal shifts in river discharge than with spring-neap changes in tidal amplitude. An unstructured grid hydrodynamic model is used to simulate conditions in the Merrimack and model results are compared quantitatively against field observations. The model achieves a high skill against time series of water level, salinity, and velocity and captures the spatial structures of salinity, velocity, and salt flux observed in along- and across-estuary transects. High model skills depend on accurate and well-resolved grid bathymetry and low background vertical and horizontal diffusivities.

  12. Equipment and Furniture Guidelines for Open-Plan Middle and High Schools.

    ERIC Educational Resources Information Center

    Lassiter, Frank

    The flexibility of open-plan space and the goals of an open education have implications for the development of furniture and equipment lists. A suggested furniture and equipment list that has been developed for one team group in one academic cluster in an academic area is presented. The selections aim at providing a wide variety of working…

  13. Development of Thin Heterojunction Solar Cells with High Open Circuit Voltage

    NASA Astrophysics Data System (ADS)

    Monga, Tanmay

    The aim of this thesis research is the development of thin silicon heterojunction solar cells with high open circuit voltage (Voc). Heterojunction solar cells are higher in efficiency than diffused junction c-Si solar cells, and they are less vulnerable to light degradation. Furthermore, the low temperature processing of heterojunction cells favour a decrease in production costs and improve cell performance at the same time. Since about 30 % of the module cost is a result of substrate cost, thin solar cells are of economic advantage than their thicker counterparts. This lead to the research for development of thin heterojunction solar cells. For high cell efficiencies and performance, it is important for cells to have a high operating voltage and Voc. Development of heterojunction cells with high Voc required a stable and repeatable baseline process on which further improvements could be made. Therefore a baseline process for heterojunction solar cells was developed and demonstrated as a pilot line at the Solar Power Lab at ASU. All the processes involved in fabrication of cells with the baseline process were optimized to have a stable and repeatable process. The cells produced with the baseline process were 19-20% efficient. The baseline process was further used as a backbone to improve and develop thin cells with even higher Voc. The process recipe was optimized with an aim to explore the limits of Voc that could be achieved with this structure on a much thinner substrate than used for the baseline process. A record Voc greater than 760mV was recorded at SPL using Suns-Voc tester on a 50 microns thick heterojunction cell without metallization. Furthermore, Voc of 754.2 mV was measured on a 50 microns thick cell with metallization by National Renewable Energy Laboratory (NREL), which is a record for Voc for heterojunction cells with metallization. High Voc corresponds to high cell efficiency and therefore, higher module voltage and power with using the same number

  14. Quantitative Analysis of the Head Scatter and Jaw Transmission Correction Factor for Commissioning of Enhanced Dynamic Wedge Fields Using a MapCHECK 2 Diode Array

    NASA Astrophysics Data System (ADS)

    Dickerson, Edward C.

    Quality assurance in radiation oncology treatment planning requires independent verification of dose to be delivered to a patient through "second check" calculations for simple plans as well as planar dose fluence measurements for more complex treatments, such as intensity modulated radiation treatments (IMRT). Discrepancies between treatment planning system (TPS) and second check calculations created a need for treatment plan verification using a two dimensional diode array for Enhanced Dynamic Wedge (EDW) fields. While these measurements met clinical standards for treatment, they revealed room for improvement in the EDW model. The purpose of this study is to analyze the head scatter and jaw transmission effects of the moving jaw in EDW fields by measuring dose profiles with a two dimensional diode array in order to minimize differences between the manufacturer provided fluence table (Golden Segmented Treatment Table) and actual machine output. The jaw transmission effect reduces the dose gradient in the wedge direction due to transmission photons adding dose to the heel region of the field. The head scatter effect also reduces the gradient in the dose profile due to decreased accelerator output at increasingly smaller field sizes caused by the moving jaw. The field size continuously decreases with jaw motion, and thus the toe region of the wedge receives less dose than anticipated due to less head scatter contribution for small field sizes. The Golden Segmented Treatment Table (GSTT) does not take these factors into account since they are specific to each individual machine. Thus, these factors need to be accounted for in the TPS to accurately model the gradient of the wedge. The TPS used in this clinic uses one correction factor (transmission factor) to account for both effects since both factors reduce the dose gradient of the wedge. Dose profile measurements were made for 5x5 cm2, 10x10 cm2, and 20x20 cm2 field sizes with open fields and 10°, 15°, 20°, 25

  15. Using meteoric 10Be to constrain the age and structure of the frontal wedge at the Japan Trench

    NASA Astrophysics Data System (ADS)

    Regalla, C.; Bierman, P. R.; Rood, D.; Motoyama, I.; Fisher, D. M.

    2013-12-01

    We present new meteoric 10Be concentration data from marine sediments recovered during International Ocean Drilling Program (IODP) Exp. 343 that help constrain the age and internal structure of the frontal prism at the Japan trench in the vicinity of the 2011 Tohoku-oki M9 earthquake rupture. Exp. 343 recovered sediments from an ~200 m interval of the frontal wedge at site C0019. Core and log observations identify the plate boundary décollement at ~820 mbsf, which separates a deformed sedimentary wedge from relatively undeformed underthrust sediments. However, reconstructions of the structural evolution of the wedge are difficult because of similarity in lithology between sediments from the incoming and overriding plate, and the chaotic character of seismic reflectors in the frontal wedge. We utilize the radiogenic decay of 10Be (t1/2 =1.36 Ma) in marine sediments to constrain variations in sediment age with depth in core C0019. Meteoric 10Be was isolated from marine sediments at the University of Vermont using total fusion and 10Be/9Be ratios were measured at the Scottish Universities Environmental Research Centre. Concentrations of meteoric 10Be in core C0019 range from 1.7x107 to 2.1x109 atm/g and are consistent with 10Be concentrations at nearby DSDP sites 436 and 434. We calculate 10Be sediment ages for analyzed samples assuming a range of initial 10Be concentrations from 1.6 to 2.1x109 atm/g. These concentrations are constrained by a 10Be sample co-located with a radiolarian micropaleontology sample at 780 mbsf that yields a Quaternary age, and from previously reported 10Be concentrations for Quaternary sediments in nearby DSDP cores. 10Be and radiolarian micropaleontology samples from similar depths yield consistent ages for late Miocene to Quaternary sediments (R2 = 0.89). Calculated 10Be ages range from 0-10 Ma, with ~50% of analyzed samples yielding ages <2 Ma. Repetition and inversion of high (109 atm/g) and low (107 atm/g) concentration sediments with

  16. Quantitative comparisons of analogue models of brittle wedge dynamics

    NASA Astrophysics Data System (ADS)

    Schreurs, Guido

    2010-05-01

    Analogue model experiments are widely used to gain insights into the evolution of geological structures. In this study, we present a direct comparison of experimental results of 14 analogue modelling laboratories using prescribed set-ups. A quantitative analysis of the results will document the variability among models and will allow an appraisal of reproducibility and limits of interpretation. This has direct implications for comparisons between structures in analogue models and natural field examples. All laboratories used the same frictional analogue materials (quartz and corundum sand) and prescribed model-building techniques (sieving and levelling). Although each laboratory used its own experimental apparatus, the same type of self-adhesive foil was used to cover the base and all the walls of the experimental apparatus in order to guarantee identical boundary conditions (i.e. identical shear stresses at the base and walls). Three experimental set-ups using only brittle frictional materials were examined. In each of the three set-ups the model was shortened by a vertical wall, which moved with respect to the fixed base and the three remaining sidewalls. The minimum width of the model (dimension parallel to mobile wall) was also prescribed. In the first experimental set-up, a quartz sand wedge with a surface slope of ˜20° was pushed by a mobile wall. All models conformed to the critical taper theory, maintained a stable surface slope and did not show internal deformation. In the next two experimental set-ups, a horizontal sand pack consisting of alternating quartz sand and corundum sand layers was shortened from one side by the mobile wall. In one of the set-ups a thin rigid sheet covered part of the model base and was attached to the mobile wall (i.e. a basal velocity discontinuity distant from the mobile wall). In the other set-up a basal rigid sheet was absent and the basal velocity discontinuity was located at the mobile wall. In both types of experiments

  17. Three-dimensional measurement of wedged scoliotic vertebrae and intervertebral disks.

    PubMed

    Aubin, C E; Dansereau, J; Petit, Y; Parent, F; de Guise, J A; Labelle, H

    1998-01-01

    Idiopathic scoliosis involves complex spinal intrinsic deformations such as the wedging of vertebral bodies (VB) and intervertebral disks (ID), and it is obvious that the clinical evaluation obtained by the spinal projections on the two-dimensional (2D) radiographic planes do not give a full and accurate interpretation of scoliotic deformities. This paper presents a method that allows reconstruction in 3D of the vertebral body endplates and measurement of the 3D wedging angles. This approach was also used to verify whether 2D radiographic measurements could lead to a biased evaluation of scoliotic spine wedging. The 3D reconstruction of VB contours was done using calibrated biplanar X-rays and an iterative projection computer procedure that fits 3D oriented ellipses of adequate diameters onto the 3D endplate contours. "3D wedging angles" of the VB and ID (representing the maximum angle between adjacent vertebrae) as well as their angular locations with respect to the vertebral frontal planes were computed by finding the positions of the shortest and longest distances between consecutive endplates along their contour. This method was extensively validated using several approaches: (1) by comparing the 3D reconstructed endplates of a cadaveric functional unit (T8-T9) with precise 3D measurements obtained using a coordinate measuring machine for 11 different combinations of vertebral angular positions; (2) by a sensitivity study on 400 different vertebral segments mathematically generated, with errors randomly introduced on the digitized points (standard deviations of 0.5, 1, 2, and 3 mm); (3) by comparing the clinical wedging measurements (on postero-anterior and lateral radiographs) at the thoracic apical level of 34 scoliotic patients (15 degrees < Cobb < 45 degrees) to the computed values. Mean errors for the 11 vertebral positions were 0.5 +/- 0.4 mm for VB thickness, less than 2.2 degrees for endplate orientation, and about 11 degrees (3 mm) for the location of

  18. Relationship between colloid osmotic pressure and pulmonary artery wedge pressure in patients with acute cardiorespiratory failure.

    PubMed

    Weil, M H; Henning, R J; Morissette, M; Michaels, S

    1978-04-01

    Close relationships between progressive respiratory failure, roentgenographic signs of pulmonary opacification and decreases in the difference between colloid osmotic pressure of plasma and the pulmonary artery wedge pressure (colloid-hydrosatic pressure gradient) were demonstrated in 49 critically ill patients with multisystem failure, in patients in shock. The potential importance of this relationship is underscored by the observation that fatal progression of pulmonary edema was related to a critical reduction in the colloid-hydrostatic pressure gradient to levels of less than 0 mm Hg. More often, reduction in colloid osmotic pressure rather than increases in left ventricular filling pressure (pulmonary artery wedge pressure) accounted for the decline in colloid-hydrostatic pressure gradient. Routine measurement of colloid osmotic pressure, preferably in conjunction with pulmonary artery wedge pressure, is likely to improve understanding of the mechanisms of acute pulmonary edema.

  19. Achieving Hard X-ray Nanofocusing Using a Wedged Multilayer Laue Lens

    SciTech Connect

    Huang, Xiaojing; Conley, Raymond; Bouet, Nathalie; Zhou, Juan; Macrander, Albert; Maser, Jorg; Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth; Harder, Ross; Robinson, Ian K.; Kalbfleisch, Sebastian; Chu, Yong S.

    2015-05-04

    Here, we report on the fabrication and the characterization of a wedged multilayer Laue lens for x-ray nanofocusing. The lens was fabricated using a sputtering deposition technique, in which a specially designed mask was employed to introduce a thickness gradient in the lateral direction of the multilayer. X-ray characterization shows an efficiency of 27% and a focus size of 26 nm at 14.6 keV, in a good agreement with theoretical calculations. Our results indicate that the desired wedging is achieved in the fabricated structure. Furthermore, we anticipate that continuous development on wedged MLLs will advance x-ray nanofocusing optics to new frontiers and enrich capabilities and opportunities for hard X-ray microscopy.

  20. Effectiveness of a Wedge Probe to Measure Sonic Boom Signatures in a Supersonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Wilcox, Floyd J., Jr.; Elmiligui, Alaa A.

    2013-01-01

    A wind tunnel investigation was conducted in the Langley Unitary Plan Wind Tunnel (UPWT) to determine the effectiveness of a wedge probe to measure sonic boom pressure signatures compared to a slender conical probe. A generic business jet model at a constant angle of attack and at a single model to probe separation distance was used to generate a sonic boom signature. Pressure signature data were acquired with both the wedge probe and a slender conical probe for comparison. The test was conducted at a Mach number of 2.0 and a free-stream unit Reynolds number of 2 million per foot. The results showed that the wedge probe was not effective in measuring the sonic boom pressure signature of the aircraft model in the supersonic wind tunnel. Data plots and a discussion of the results are presented. No tabulated data or flow visualization photographs are included.