Science.gov

Sample records for open wedge high

  1. Effect of Wedge Insertion Angle on Posterior Tibial Slope in Medial Opening Wedge High Tibial Osteotomy

    PubMed Central

    Ogawa, Hiroyasu; Matsumoto, Kazu; Ogawa, Takahiro; Takeuchi, Kentaro; Akiyama, Haruhiko

    2016-01-01

    Background: Medial opening wedge high tibial osteotomy (HTO) is a well-established surgery for medial compartment knee osteoarthritis (OA) wherein the lower extremity is realigned to shift the load distribution from the medial compartment of the knee to the lateral compartment. However, this surgery is known to affect the posterior tibial slope angle (PTSA), which could lead to abnormal knee kinematics and instability, and eventually to knee OA. Although PTSA control is as important as coronal realignment, few appropriate measurements for this parameter have been reported. The placement of a wedge spacer might have an effect on PTSA. Purpose: To elucidate the relationship between the PTSA and the direction of insertion of a wedge spacer. Study Design: Case series; Level of evidence, 4. Methods: This study assessed 43 knees from 34 patients who underwent medial opening wedge HTO for knee OA. Pre- and postoperative lateral radiographs of the knee as well as postoperative computed tomography scans were performed to evaluate the relationship among PTSA, wedge insertion angle (WIA), and opening gap ratio (distance of the anterior opening gap/distance of the posterior opening gap at the osteotomy site). Results: The PTSA significantly increased from 9.0° ± 2.8° preoperatively to 13.2° ± 4.1° postoperatively (P < .001), resulting in a mean ΔPTSA of 4.7° ± 4.5°. The mean opening gap ratio was 0.86 ± 0.11, and the mean WIA was 25.9° ± 8.4°. The WIA and opening gap ratio were both highly correlated with ΔPTSA (r = 0.71 and 0.72, respectively), implying that a smaller WIA or smaller gap ratio leads to less increase in posterior slope. Conclusion: The direction of wedge insertion is highly correlated with PTSA increase, which suggests that the PTSA can be controlled for by adjusting the direction of wedge insertion during surgery. Clinical Relevance: Study results suggest that it is possible to adjust the PTSA by controlling the WIA during surgery. Proper

  2. Comparison of clinical and radiological outcomes between opening-wedge and closing-wedge high tibial osteotomy: A comprehensive meta-analysis

    PubMed Central

    Wu, Lingfeng; Lin, Jun; Jin, Zhicheng; Cai, Xiaobin; Gao, Weiyang

    2017-01-01

    High tibial osteotomy (HTO) has been widely used for clinical treatment of osteoarthritis of the medial compartment of the knee, and both opening-wedge and closing-wedge HTO are the most commonly used methods. However, it remains unclear which technique has better clinical and radiological outcomes in practice. To systematically evaluate this issue, we conducted a comprehensive meta-analysis by pooling all available data for the opening-wedge HTO and closing-wedge HTO techniques from the electronic databases including PubMed, Embase, Wed of Science and Cochrane Library. A total of 22 studies encompassing 2582 cases were finally enrolled in the meta-analysis. There was no significant difference regarding surgery time, duration of hospitalization, knee pain VAS, Lysholm score and HSS knee score (clinical outcomes) between the opening-wedge and closing-wedge HTO groups (P > 0.05). However, the opening-wedge HTO group showed wider range of motion than the closing-wedge HTO group (P = 0.003). Moreover, as for Hip-Knee-Ankle angle and mean angle of correction, no significant difference was observed between the opening-wedge and closing-wedge HTO groups (P > 0.05), while the opening-wedge HTO group showed greater posterior tibial slope angle (P < 0.001) and lesser patellar height than the closing-wedge HTO group (P < 0.001). On light of the above analysis, we believe that individualized surgical approach should be introduced based on the clinical characteristics of each patient. PMID:28182736

  3. 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

  4. 3D Surgical Printing Cutting Guides for Open-Wedge High Tibial Osteotomy: Do It Yourself.

    PubMed

    Pérez-Mañanes, Rubén; Burró, Juan Arnal; Manaute, Jose Rojo; Rodriguez, Francisco Chana; Martín, Javier Vaquero

    2016-11-01

    Opening wedge osteotomy has recently gained popularity, thanks to the recent implementation of locking plates, which have shown equivalent stability with greater reproducibility, accuracy, and longevity than the closing wedge techniques and a lower prosthetic conversion rate. We present a new "do-it-yourself" cutting guides system for tibial opening osteotomy. Using a conventional computed tomography digital image, a positioning guide and wedge spacers were printed in three dimensions (3D) for implementing the osteotomy and obtaining the planned correction. The surgeon makes the whole process in a do-it-yourself style. This new technique was used in eight cases. Previous opening osteotomies with the standard technique were used as control (20 cases). Surgical time, fluoroscopic time, and accuracy of the axial correction were measured. The use of a custom positioning guide reduced the surgical (31 minutes less) and fluoroscopic times (6.9 times less) while achieving a high-axis correction accuracy compared with the standard technique. Digitally planned and executed osteotomies under 3D printed osteotomy positioning guides help the surgeon to minimize human error while reducing surgical time. The reproducibility of this technique is very robust, allowing a transfer of the steps planned in a virtual environment to the operating table.

  5. Personalized implant for high tibial opening wedge: combination of solid freeform fabrication with combustion synthesis process.

    PubMed

    Zhim, Fouad; Ayers, Reed A; Moore, John J; Moufarrège, Richard; Yahia, L'Hocine

    2012-09-01

    In this work a new generation of bioceramic personalized implants were developed. This technique combines the processes of solid freeform fabrication (SFF) and combustion synthesis (CS) to create personalized bioceramic implants with tricalcium phosphate (TCP) and hydroxyapatite (HA). These porous bioceramics will be used to fill the tibial bone gap created by the opening wedge high tibial osteotomy (OWHTO). A freeform fabrication with three-dimensional printing (3DP) technique was used to fabricate a metallic mold with the same shape required to fill the gap in the opening wedge osteotomy. The mold was subsequently used in a CS process to fabricate the personalized ceramic implants with TCP and HA compositions. The mold geometry was designed on commercial 3D CAD software. The final personalized bioceramic implant was produced using a CS process. This technique was chosen because it exploits the exothermic reaction between P₂O₅ and CaO. Also, chemical composition and distribution of pores in the implant could be controlled. To determine the chemical composition, the microstructure, and the mechanical properties of the implant, cylindrical shapes were also fabricated using different fabrication parameters. Chemical composition was performed by X-ray diffraction. Pore size and pore interconnectivity was measured and analyzed using an electronic microscope system. Mechanical properties were determined by a mechanical testing system. The porous TCP and HA obtained have an open porous structure with an average 400 µm channel size. The mechanical behavior shows great stiffness and higher load to failure for both ceramics. Finally, this personalized ceramic implant facilitated the regeneration of new bone in the gap created by OWHTO and provides additional strength to allow accelerated rehabilitation.

  6. The SPECT/CT Evaluation of Compartmental Changes after Open Wedge High Tibial Osteotomy

    PubMed Central

    Kim, Tae Won; Kim, Byung Kag; Kim, Dong Whan; Sim, Jae Ang; Lee, Beom Koo; Lee, Yong Seuk

    2016-01-01

    Purpose The purpose of this study was to evaluate compartmental changes using combined single-photon emission computerized tomography and conventional computerized tomography (SPECT/CT) after open wedge high tibial osteotomy (OWHTO) for providing clinical guidance for proper correction. Materials and Methods Analysis was performed using SPECT/CT from around 1 year after surgery on 22 patients who underwent OWHTO. Postoperative mechanical axis was measured and classified into 3 groups: group I (varus), group II (0°–3° valgus), and group III (>3° valgus). Patella location was evaluated using Blackburne-Peel (BP) ratio. On SPECT/CT, the knee joint was divided into medial, lateral, and patellofemoral compartments and the brighter signal was marked as a positive signal. Results Increased signal activity in the medial compartment was observed in 12 cases. No correlation was observed between postoperative mechanical axis and medial signal increase. Lateral increased signal activity was observed in 3 cases, and as valgus degree increased, lateral compartment’s signal activity increased. Increased signal activity of the patellofemoral joint was observed in 7 cases, and significant correlation was observed between changes in BP ratio and increased signal activity. Conclusions For the treatment of medial osteoarthritis, OWHTO requires overcorrection that does not exceed 3 valgus. In addition, the possibility of a patellofemoral joint problem after OWHTO should be kept in mind. PMID:27894172

  7. 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

  8. Open Wedge High Tibial Osteotomy and Combined Arthroscopic Surgery in Severe Medial Osteoarthritis and Varus Malalignment: Minimum 5-Year Results

    PubMed Central

    Yoo, Moon-Jib; Shin, Yong-Eun

    2016-01-01

    Purpose To evaluate the radiologic and functional outcomes of medial open wedge high tibial osteotomy (HTO) combined with arthroscopic procedure in patients with medial osteoarthritis. Materials and Methods From June 1996 to March 2010, 26 patients (32 knees) who underwent medial open wedge osteotomy and arthroscopic operation for medial osteoarthritis were retrospectively reviewed. Measurements included hip-knee-ankle (HKA) angle, femorotibial angle, medial proximal tibial angle, posterior tibial slope angle, and Kellgren-Lawrence grade. Clinical evaluation was performed using Lysholm knee scoring scale and knee and function score of the American Knee Society. Results Differences between the mean preoperative and postoperative measurements were significant in all angles including the HKA angle (−5.7° and +5.5°), femorotibial angle (−1.9° and +9.8°), and medial proximal tibial angle (82.9° and 90.5°) (p<0.05). Mean Lysholm knee scoring scale was 63.6 preoperatively and 88.7 at the last follow-up, mean Knee Society knee score was 61.2 and 86.6, and mean function score was 59.3 and 87.2, respectively. All differences were significant (p<0.05). Conclusions Medial open wedge HTO in combination with arthroscopic procedure is an effective treatment method for medial osteoarthritis to treat varus deformity and an intra-articular lesion. PMID:27894173

  9. Comparison of theoretical fixation stability of three devices employed in medial opening wedge high tibial osteotomy: a finite element analysis

    PubMed Central

    2014-01-01

    Background Medial open wedge high tibial osteotomy is a well-established procedure for the treatment of unicompartmental osteoarthritis and symptomatic varus malalignment. We hypothesized that different fixation devices generate different fixation stability profiles for the various wedge sizes in a finite element (FE) analysis. Methods Four types of fixation were compared: 1) first and 2) second generation Puddu plates, and 3) TomoFix plate with and 4) without bone graft. Cortical and cancellous bone was modelled and five different opening wedge sizes were studied for each model. Outcome measures included: 1) stresses in bone, 2) relative displacement of the proximal and distal tibial fragments, 3) stresses in the plates, 4) stresses on the upper and lower screw surfaces in the screw channels. Results The highest load for all fixation types occurred in the plate axis. For the vast majority of the wedge sizes and fixation types the shear stress (von Mises stress) was dominating in the bone independent of fixation type. The relative displacements of the tibial fragments were low (in μm range). With an increasing wedge size this displacement tended to increase for both Puddu plates and the TomoFix plate with bone graft. For the TomoFix plate without bone graft a rather opposite trend was observed. For all fixation types the occurring stresses at the screw-bone contact areas pulled at the screws and exceeded the allowable threshold of 1.2 MPa for at least one screw surface. Of the six screw surfaces that were studied, the TomoFix plate with bone graft showed a stress excess of one out of twelve and without bone graft, five out of twelve. With the Puddu plates, an excess stress occurred in the majority of screw surfaces. Conclusions The different fixation devices generate different fixation stability profiles for different opening wedge sizes. Based on the computational simulations, none of the studied osteosynthesis fixation types warranted an intransigent full

  10. Tibial nerve neuropathy following medial opening-wedge high tibial osteotomy-case report of a rare technical complication.

    PubMed

    Shin, Young-Soo; Sim, Hyun-Bo; Yoon, Jung-Ro

    2017-03-21

    A 63-year-old woman developed tibial nerve injury caused by an overlong K wire and 4.5-mm cortical lag screw through the first distal hole below the osteotomy during medial opening-wedge high tibial osteotomy (HTO), leading to a lack of sensation on the sole of the foot with no disturbances in motor functions. The temporary lag screw in the first distal hole below the osteotomy is often inserted by an excessive length in order to compress the potentially fractured opposite cortex. By doing so, posterior neurovascular structures including the tibial nerve and the popliteal vessels can be injured. To avoid this type of injury during medial opening-wedge HTO, proper knee position and appropriate Hohmann retractor position in combination with meticulous insertion of the K wire or screw under fluoroscopic control are essential. In addition, our study reinforces the fact that different presentations of injury to the tibial nerve should be carefully considered in the absence of common diagnostic features, including weakness of the toe flexors and posterior tibial muscle of the leg with intractable pain.

  11. Utilizing reamer irrigator aspirator (RIA) autograft for opening wedge high tibial osteotomy: A new surgical technique and report of three cases☆

    PubMed Central

    Seagrave, Richard A.; Sojka, John; Goodyear, Adam; Munns, Stephen W.

    2013-01-01

    INTRODUCTION The lateral closing wedge high tibial osteotomy (HTO) was popularized by Coventry in the 1960s. In the 1990s the medial opening wedge osteotomy gained popularity because it could achieve greater valgus correction and it did not require dissociation of the fibula from the tibia, an important consideration when treating varus knees with lateral and posterolateral ligament deficiencies (Noyes’ double-varus and triple-varus knees). However, it has the disadvantage of requiring bone graft to fill bony defects. Recently, the reamer-irrigator-aspirator (RIA; Synthes, Paoli, PA) system was developed, and as a result of this procedure, a large amount of usable autogenous bone graft can be collected safely for use. To our knowledge, there is no published series combining opening wedge HTO with the use of RIA obtained autogenous bone graft. PRESENTATION OF CASE We present a novel technique in which a series of three patients underwent opening wedge HTO using ipsilateral, retrograde femur RIA graft to fill the bone defect. All patients had satisfactory clinical and radiologic outcomes following the new technique at latest follow up. DISCUSSION Opening wedge high tibial osteotomy is a well-documented and accepted orthopedic procedure, however, has the disadvantage of requiring varying amounts of bone graft. Traditionally, iliac crest or tricortical allograft have been the grafting modalities of choice, however both have inherent drawbacks to their use. In our series, the use of RIA autograft is a safe and reliable harvest technique for high tibial osteotomy, providing abundant and quality autogenous bone graft. CONCLUSION All three of our patients achieved radiographic union with high clinical patient satisfaction without any major complications. We feel this novel technique is a safe and acceptable operative solution grafting opening wedge osteotomies about the knee. PMID:24412805

  12. 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

  13. Management of Osteoarthritis Knee by Graduated Open Wedge High Tibial Osteotomy in 40-60 Years Age Group Using Limb Reconstruction System: A Clinical Study

    PubMed Central

    Sharma, Pawan Kumar; Chugh, Ankush; Singh, Randhir

    2015-01-01

    Background With i ncrease in elderly population, osteoarthritis has become major concern nowadays. Knee joint is most commonly affected joint. A number of methods have been developed in the last few years which help in treating the osteoarthritis knee, which includes non pharmacological, pharmacological and surgical methods. Among the most promising techniques with renewed interest for osteoarthritis knee with deformity is the use of high tibial osteotomy. Uni-compartmental osteoarthritis knee with deformity especially in relatively younger age group (less than 60 years) constitutes the main indication. Aim The aim of present study was to evaluate management of osteoarthritis knee by graduated open wedge high tibial osteotomy in 40-60 years age group using limb reconstruction system. Materials and Methods Medial Opening Wedge High Tibial Osteotomy leaving the lateral cortex intact which acts as a hinge, was done in 30 patients and stabilized by Limb Reconstruction System. Distraction was started at 7th day at the rate of 1 mm/day and continued till proper alignment was achieved. Results Medial Opening Wedge High Tibial Osteotomy stabilized by unilateral external fixator is a good method for unicompartmental osteoarthritis knee with deformity as it gives precise control over final limb alignment and its ability to perform a residual correction. Deformity correction can be quantified at the time of correction as it is not acute correction. Gradual deformity correction can be done over time by distraction histogenesis with the help of unilateral external fixator. It is also a good method in young patients requiring large correction. Conclusion Medial Opening Wedge High Tibial Osteotomy is having many benefits over closed wedge osteotomy and stabilization by unilateral external fixator also has its added benefits. It is less invasive, no internal hardware present and safer in terms of neurovascular complications. PMID:26557580

  14. Improvement of the knee center of rotation during walking after opening wedge high tibial osteotomy.

    PubMed

    Kim, Kyungsoo; Feng, Jun; Nha, Kyung Wook; Park, Won Man; Kim, Yoon Hyuk

    2015-06-01

    Accurate measurement of the center of rotation of the knee joint is indispensable for prediction of joint kinematics and kinetics in musculoskeletal models. However, no study has yet identified the knee center of rotations during several daily activities before and after high tibial osteotomy surgery, which is one surgical option for treating knee osteoarthritis. In this study, an estimation method for determining the knee joint center of rotation was developed by applying the optimal common shape technique and symmetrical axis of rotation approach techniques to motion-capture data and validated for typical activities (walking, squatting, climbing up stairs, walking down stairs) of 10 normal subjects. The locations of knee joint center of rotations for injured and contralateral knees of eight subjects with osteoarthritis, both before and after high tibial osteotomy surgery, were then calculated during walking. It was shown that high tibial osteotomy surgery improved the knee joint center of rotation since the center of rotations for the injured knee after high tibial osteotomy surgery were significantly closer to those of the normal healthy population. The difference between the injured and contralateral knees was also generally reduced after surgery, demonstrating increased symmetry. These results indicate that symmetry in both knees can be recovered in many cases after high tibial osteotomy surgery. Moreover, the recovery of center of rotation in the injured knee was prior to that of symmetry. This study has the potential to provide fundamental information that can be applied to understand abnormal kinematics in patients, diagnose knee joint disease, and design a novel implants for knee joint surgeries.

  15. RADIOGRAPHIC ASSESSMENT OF THE OPENING WEDGE PROXIMAL TIBIAL OSTEOTOMY

    PubMed Central

    Silva, Carlos Francisco Bittencourt; Camara, Eduardo Kastrup Bittencourt; Vieira, Luiz Antonio; Adolphsson, Fernando; Rodarte, Rodrigo Ribeiro Pinho

    2015-01-01

    Objective: To radiographically evaluate individuals who underwent opening wedge proximal tibial osteotomy, with the aim of analyzing the proximal tibial slope in the frontal and sagittal planes, and the patellar height. Method: The study included 22 individuals who were operated at the National Traumatology and Orthopedics Institute (INTO) for correction of varus angular tibial deviation using the opening wedge osteotomy (OWO) technique with the Orthofix monolateral external fixator. Patients with OWO whose treatment was completed between January 2000 and December 2006 were analyzed. The measurement technique consisted of using anteroposterior radiographs with loading and lateral views with the operated knees flexed at 30°. Results: There were no statistically significant differences between the pre and postoperative tibial slope and patellar height values in the patients evaluated. Conclusion: Opening wedge proximal tibial osteotomy is a technique that avoids the problems presented by high proximal tibial osteotomy, since it is done without causing changes to the extensor mechanism, ligament imbalance or distortions in the proximal tibia. PMID:27022577

  16. ACL injury while jumping rope in a patient with an unintended increase in the tibial slope after an opening wedge high tibial osteotomy.

    PubMed

    Jung, Kwang Am; Lee, Su Chan; Hwang, Seung Hyun; Song, Moon Bok

    2009-08-01

    High tibial osteotomy (HTO) is an accepted surgical technique for the treatment of medial compartmental arthrosis of the knee in younger patients. Compared to total knee arthroplasty, HTO may be a good choice in patients who wish to continue with heavy labor and/or impact sports. Based on the rehabilitation protocol after HTO, impact sports, such as running, jumping rope, and full sports activities, are generally permitted 6 months postoperatively. Jumping rope is an excellent form of aerobic exercise, and when done properly, jumping rope can lead to a dramatic improvement in rehabilitation and full sports activities. However, an adequate evaluation should be performed prior to initiating impact sports. We present the case of a ruptured anterior cruciate ligament that occurred in a patient with an unintended increase in the tibial slope after an opening wedge HTO who was jumping rope.

  17. Complications and Short-Term Outcomes of Medial Opening Wedge High Tibial Osteotomy Using a Locking Plate for Medial Osteoarthritis of the Knee

    PubMed Central

    Seo, Seung-Suk; Kim, Ok-Gul; Seo, Jin-Hyeok; Kim, Do-Hoon; Kim, Youn-Gu; Lee, In-Seung

    2016-01-01

    Purpose The purpose of this study was to investigate complications and radiologic and clinical outcomes of medial opening wedge high tibial osteotomy (MOWHTO) using a locking plate. Materials and Methods This study reviewed 167 patients who were treated with MOWHTO using a locking plate from May 2012 to June 2014. Patients without complications were classified into group 1 and those with complications into group 2. Medical records, operative notes, and radiographs were retrospectively reviewed to identify complications. Clinically, Oxford Knee score and Knee Injury and Osteoarthritis Outcome score (KOOS) were evaluated. Results Overall, complications were observed in 49 patients (29.3%). Minor complications included lateral cortex fracture (15.6%), neuropathy (3.6%), correction loss (2.4%), hematoma (2.4%), delayed union (2.4%), delayed wound healing (2.4%), postoperative stiffness (1.2%), hardware irritation (1.2%), tendinitis (1.2%), and hardware failure without associated symptoms (0.6%). Major complications included hardware failure with associated symptoms (0.6%), deep infection (0.6%), and nonunion (0.6%). At the first-year follow-up, there were no significant differences in radiologic measurements between groups 1 and 2. There were no significant differences in knee scores except for the KOOS pain score. Conclusions Our data showed that almost all complications of the treatment were minor and the patients recovered without any problems. Most complications did not have a significant impact on radiologic and clinical outcomes. PMID:27894176

  18. Modified Iliac Crest Reconstruction with Bone Cement for Reduction of Donor Site Pain and Morbidity after Open Wedge High Tibial Osteotomy: A Prospective Study

    PubMed Central

    Lee, Jong Seong; Park, Yong Jee; Wang, Lih; Chang, Yong Suk; Shetty, Gautam M.; Nha, Kyung Wook

    2016-01-01

    Purpose This study was to determine the efficacy of iliac crest reconstruction using bone cement in reducing pain and morbidity at the donor site in patients undergoing open wedge high tibial osteotomy (OWHTO) with tricortical iliac crest autologous graft. Materials and Methods Thirty-three patients who underwent iliac crest reconstruction using polymethyl methacrylate (PMMA) bone cement (group A) and thirty patients who had no iliac crest reconstruction (group B) were enrolled in this study. All patients were evaluated for pain and functional disability related to graft harvesting using the pain and functional visual analogue scale (VAS) score during hospital stay and at 6 weeks, 3 months, and 6 months postoperatively. Results There was significant difference between the two groups in terms of pain and function. The pain VAS score was significantly lower in group A than group B during the first 2 weeks postoperatively (p=0.04) and the functional VAS score was also significantly lower in group A during the first 2 weeks postoperatively (p<0.001) in terms of breathing, sitting up from the supine position, and standing up with crutches from the sitting position. Conclusions Iliac crest donor site reconstruction using PMMA bone cement in patients undergoing OWHTO significantly decreased pain and improved function during the first 2 weeks postoperatively when compared to patients who underwent OWHTO without iliac crest reconstruction. PMID:27894174

  19. Comparison of Cable Method and Miniaci Method Using Picture Archiving and Communication System in Preoperative Planning for Open Wedge High Tibial Osteotomy

    PubMed Central

    Yoon, Seong-Dae; Zhang, GuoFeng; Kim, Hee-June; Lee, Byoung-Joo; Kyung, Hee-Soo

    2016-01-01

    Purpose The purpose was to compare the accuracy of Miniaci method using picture archiving and communication system (PACS) with a cable method in high tibial osteotomy (HTO). Materials and Methods This study analyzed 47 patients (52 knees) with varus deformity and medial osteoarthritis. From 2007 to 2013, patients underwent HTO using either a cable method (20 knees) or Miniaci method based on a PACS image (32 knees). In the cable method, the 62.5% point of the mediolateral tibial plateau width was located using an electrocautery cord under fluoroscopy (cable group). The Miniaci method used preoperative radiographs to shift the weight bearing axis (PACS group). Full-length lower limb radiographs obtained preoperatively and at the sixth postoperative week were used to compare the percentage of crossing point of the weight bearing line on the tibial plateau with respect to the medial border. Results The weight bearing line on the tibial plateau was corrected from a preoperative 11.0±7.0% to a postoperative 47.2±7.4% in the cable group and from 12.7±4.9% to 59.5±5.3% in the PACS group. The mechanical femorotibial angle was corrected from varus 8.9±3.7° to valgus 0.3±4.0° in the cable group and from varus 9.0±3.3° to valgus 2.9±2.6° in the PACS group. Conclusions In HTO, correction based on the Miniaci method using a PACS was more accurate than correction using the cable method. PMID:27894175

  20. Measurement of photoneutron dose produced by wedge filters of a high energy linac using polycarbonate films.

    PubMed

    Hashemi, Seyed Mehdi; Hashemi-Malayeri, Bijan; Raisali, Gholamreza; Shokrani, Parvaneh; Sharafi, Ali Akbar; Torkzadeh, Falamarz

    2008-05-01

    Radiotherapy represents the most widely spread technique to control and treat cancer. To increase the treatment efficiency, high energy linacs are used. However, applying high energy photon beams leads to a non-negligible dose of neutrons contaminating therapeutic beams. In addition, using conventional linacs necessitates applying wedge filters in some clinical conditions. However, there is not enough information on the effect of these filters on the photoneutrons produced. The aim of this study was to investigate the change of photoneutron dose equivalent due to the use of linac wedge filters. A high energy (18 MV) linear accelerator (Elekta SL 75/25) was studied. Polycarbonate films were used to measure the dose equivalent of photoneutrons. After electrochemical etching of the films, the neutron dose equivalent was calculated using Hp(10) factor, and its variation on the patient plane at 0, 5, 10, 50 and 100 cm from the center of the X-ray beam was determined. By increasing the distance from the center of the X-ray beam towards the periphery, the photoneutron dose equivalent decreased rapidly for the open and wedged fields. Increasing of the field size increased the photoneutron dose equivalent. The use of wedge filter increased the proportion of the neutron dose equivalent. The increase can be accounted for by the selective absorption of the high energy photons by the wedge filter.

  1. 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...

  2. Opening-wedge osteotomy for angular deformities of long bones in children.

    PubMed

    Scheffer, M M; Peterson, H A

    1994-03-01

    Mild angular deformities associated with a mild limb-length discrepancy of long bones in children can be treated effectively with opening-wedge osteotomy with insertion of a specially prepared autogenous tricortical iliac-crest bone graft and with minimum or no internal fixation. Thirty-one osteotomies in twenty-six children satisfactorily corrected the deformities so that the angulation and length of the bone were comparable with the values on the normal, contralateral side. Physeal arrest or ipsilateral excision of a physeal bar was performed either concomitantly or at a separate operation in twenty-one of the twenty-six patients, to aid in the treatment of the limb-length discrepancy. Opening-wedge osteotomy is applicable for correction when the angular deformity is 25 degrees or less and the limb-length discrepancy is, or will be, twenty-five millimeters or less at maturity.

  3. Outcomes of Opening Wedge Osteotomy to Correct Angular Deformity in Small Finger Clinodactyly

    PubMed Central

    Piper, Samantha L.; Goldfarb, Charles A.

    2015-01-01

    Purpose To evaluate the outcomes and complications in a series of children with clinodactyly treated with opening wedge osteotomy of the abnormal phalanx. Methods We performed a retrospective review of all children with clinodactyly treated at our institution with opening wedge osteotomy of the abnormal middle phalanx between 2003 and 2013. Patients with concomitant pathology or prior surgery in the affected finger were excluded. Pre and postoperative clinical angle, radiographic angle, digital range of motion, and pain were compared, and complications were recorded. Results Thirteen digits in 9 patients were included. All had greater than 20° of preoperative clinical angulation (mean 36°). Mean age at the time of surgery was 11 years and mean duration of follow-up was 25 months (12–43 months). All digits had significant improvement (mean 32°) in clinical and radiographic angles after surgery. This improvement was maintained at final follow-up in 12 digits. Six patients had pain preoperatively and no patient had pain postoperatively. One digit had a recurrent deformity at final follow-up, and 3 digits developed stiffness at the distal interphalangeal joint. Conclusions Opening wedge osteotomy is an effective treatment for angulation in children with clinodactyly. We counsel families regarding the risk of distal interphalangeal joint stiffness. Level of Evidence: Therapeutic Level IV PMID:25754787

  4. Impact of sedimentation on evolution of accretionary wedges: Insights from high-resolution thermomechanical modeling

    NASA Astrophysics Data System (ADS)

    Mannu, Utsav; Ueda, Kosuke; Willett, Sean D.; Gerya, Taras V.; Strasser, Michael

    2016-12-01

    Syntectonic sedimentation history is a potential cause of differentiated accretionary wedge structures along the subduction margin. Recent efforts to model the role of sedimentation on wedge evolution have highlighted the importance of spatiotemporal history of sedimentation on the evolution of the wedge. Moreover, reconstruction of deformation history of the accretionary wedges using reflection seismic and borehole data has further substantiated the impact of sedimentation on wedge evolution. We conduct several numerical experiments using a high-resolution dynamic 2-D thermomechanical plate subduction model to systematically investigate and quantify different effects of sedimentation on accretionary wedge evolution. Models with sedimentation suggest migration of deformation to parts of the wedge lying outside the sedimentation zone leading to emergence/reactivation of out-of-sequence thrusts (OOSTs). Frequency and length of new thrust sheets are correlated with sedimentation in the trench. Models undergo a transition period of 1.5 Myr following the onset of sedimentation, after which they continue to grow under a new steady state. Stabilization of the wedge and increased load on the oceanic plate due to sedimentation create conditions in which smaller wedge-top basins combine to form a large and flat forearc basin. Last but not the least, emergence of OOST in models of accretionary wedges undergoing sedimentation provides important insights in to evolution of potentially tsunamigenic OOSTs like the Megasplay Fault seaward of the Kumano forearc basin.

  5. Crack-opening displacements in center-crack, compact, and crack-line wedge-loaded specimens. [of flat plates

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr.

    1976-01-01

    The theoretical crack-opening displacements for center-crack, compact, and crack-line wedge-loaded specimens (reported in the ASTM Proposed Recommended Practice for R-Curve Determination (1974)) disagree with experimental measurements in the literature. The disagreement is a result of using approximate specimen configurations and load representation to obtain the theoretical displacements. An improved method of boundary collocation is presented which was used to obtain the theoretical displacements in these three specimen types; the actual specimen configurations and more accurate load representation were used. In the analysis of crack-opening displacements in the compact and crack-line wedge-loaded specimens, the effects of the pin-loaded holes were also included. The theoretical calculations agree with the experimental measurements reported in the literature. Also examined are accurate polynomial expressions for crack-opening displacements in both compact and crack-line wedge-loaded specimens.

  6. Generation of high-order optical vortices by optical wedges system

    NASA Astrophysics Data System (ADS)

    Izdebskaya, Ya. V.; Shvedov, V. G.; Volyar, A. V.

    2005-11-01

    The aim of the given report is experimental and theoretical research of the diffraction of a Gaussian beam by the optical wedges system. It is shown that this system is able to form high-order optical vortices. The effectiveness of system is about 90%. It was shown, that each wedge changes a charge of phase singularity as a result of edge diffraction. The value topological charge of the optical vortex formed after system is defined by the number of wedges in the system. Changing mutual orientation corners of wedges we can select required conditions of the vortex core. It was revealed that the optical vortex appears structurally steady if the comer of mutual orientation of wedges equals α = πn (where n-number of wedges).

  7. Anterior opening wedge osteotomy of the proximal tibia for anterior knee pain in idiopathic hyperextension knees

    PubMed Central

    van Raaij, T. M.

    2006-01-01

    We analysed 20 patients with 24 knees affected by idiopathic genu recurvatum who were treated with an anterior opening wedge osteotomy of the proximal tibia because of anterior knee pain. We managed to attain full satisfaction in 83% of the patients with a mean follow-up of 7.4 years. The mean Hospital for Special Surgery score was 90.3 (range 70.5–99.5), and the mean Knee Society score score was 94.6 (70–100) for function and 87.7 (47–100) for pain. The mean Western Ontario and McMaster University Osteoarthritis Index score for knee function was 87.5 (42–100), for stiffness 82.8 (25–100) and for pain 87.3 (55–100). Radiographs showed a significant increase in posterior tibial slope of 9.4 deg and a significant decrease of patellar height according to the Blackburne–Peel method of 0.16 postoperatively. No cases of non-union, deep infection or compartment syndrome were seen. No osteoarthritic changes in the lateral or medial knee compartment were found with more than 5 years’ follow-up in 16 patients with 19 affected knees. Three out of the four dissatisfied patients had a patella infera which led to patellofemoral complaints. One patient in the study underwent a secondary superior displacement of the patella with excellent results. We conclude that in a selected group of patients with idiopathic genu recurvatum and anterior knee pain an opening wedge osteotomy of the proximal tibia can be beneficial. PMID:16521014

  8. Predicting translational deformity following opening-wedge osteotomy for lower limb realignment.

    PubMed

    Barksfield, Richard C; Monsell, Fergal P

    2015-11-01

    An opening-wedge osteotomy is well recognised for the management of limb deformity and requires an understanding of the principles of geometry. Translation at the osteotomy is needed when the osteotomy is performed away from the centre of rotation of angulation (CORA), but the amount of translation varies with the distance from the CORA. This translation enables proximal and distal axes on either side of the proposed osteotomy to realign. We have developed two experimental models to establish whether the amount of translation required (based on the translation deformity created) can be predicted based upon simple trigonometry. A predictive algorithm was derived where translational deformity was predicted as 2(tan α × d), where α represents 50 % of the desired angular correction, and d is the distance of the desired osteotomy site from the CORA. A simulated model was developed using TraumaCad online digital software suite (Brainlab AG, Germany). Osteotomies were simulated in the distal femur, proximal tibia and distal tibia for nine sets of lower limb scanograms at incremental distances from the CORA and the resulting translational deformity recorded. There was strong correlation between the distance of the osteotomy from the CORA and simulated translation deformity for distal femoral deformities (correlation coefficient 0.99, p < 0.0001), proximal tibial deformities (correlation coefficient 0.93-0.99, p < 0.0001) and distal tibial deformities (correlation coefficient 0.99, p < 0.0001). There was excellent agreement between the predictive algorithm and simulated translational deformity for all nine simulations (correlation coefficient 0.93-0.99, p < 0.0001). Translational deformity following corrective osteotomy for lower limb deformity can be anticipated and predicted based upon the angular correction and the distance between the planned osteotomy site and the CORA.

  9. Monolithic integration of high-Q wedge resonators with vertically coupled waveguides

    NASA Astrophysics Data System (ADS)

    Ramiro-Manzano, Fernando; Prtljaga, Nikola; Pavesi, Lorenzo; Pucker, Georg; Ghulinyan, Mher

    2013-05-01

    Typical UHQ resonators, microspheres and microtoroids, lack the possibility of integration into lightwave circuits due to their planarity constrains. In this context, CMOS-compatible alternatives in the form of wedge resonators have been proposed. However, the mode retraction from the wedge cavity inhibits the possibility to side couple with integrated waveguides and therefore, halts the full integration within a planar lightwave circuit. In this work, we propose and demonstrate experimentally the complete integration of wedge resonators with vertically coupled dielectric bus waveguides. This coupling scheme permits to use arbitrary gaps, geometries and materials, enables simplified and precise control of the light injection into the cavity and opens the door to an industrial mass-fabrication of UHQ resonators.

  10. 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.

  11. 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

  12. Wedge Absorbers for Final Cooling for a High-Energy High-Luminosity Lepton Collider

    SciTech Connect

    Neuffer, David; Mohayai, Tanaz; Snopok, Pavel; Summers, Don

    2016-06-01

    A high-energy high-luminosity muon collider scenario requires a "final cooling" system that reduces transverse emittance to ~25 microns (normalized) while allowing longitudinal emittance increase. Ionization cooling using high-field solenoids (or Li Lens) can reduce transverse emittances to ~100 microns in readily achievable configurations, confirmed by simulation. Passing these muon beams at ~100 MeV/c through cm-sized diamond wedges can reduce transverse emittances to ~25 microns, while increasing longitudinal emittance by a factor of ~5. Implementation will require optical matching of the exiting beam into downstream acceleration systems.

  13. Clinical and radiological outcome after mini-open Latarjet technique with fixation of coracoid with Arthrex wedge mini-plate

    PubMed Central

    Chaudhary, Deepak; Goyal, Ankit; Joshi, Deepak; Jain, Vineet; Mohindra, Mukul; Mehta, Nitin

    2016-01-01

    Background Technical faults leading to coracoid fractures during screw insertion and coracoid graft osteolysis are concerns with standard screw fixation techniques in Latarjet procedure. The purpose of this study is to share our experience using Arthrex wedge profile plate with mini-open technique for graft fixation, that ensures better load distribution between coracoid graft and glenoid. Methods We did retrospective analysis of 24 patients with recurrent anterior shoulder instability after failed arthroscopic Bankart's repair. Arthroscopic examination of affected shoulder was done in lateral position before making patient supine for open Latarjet. A low profile wedge plate (Arthrex) with two screws was used for the procedure. CT analysis was performed post-operatively at 6 months to see graft union and results were evaluated using the Rowe and Walch Duplay score. Results Mean follow-up time was 26 months. Postoperatively, mean forward elevation was 170.6 + 4.6° (loss of average 5.9°) and mean external rotation was 42.5 + 5.3° (loss of average 3.1°). All patients returned to their previous occupation. None reported to be having any recurrent subluxation. Functional assessment done using Rowe score and Walch Duplay score showed statistically significant improvement (p value 0.034). There were no implant-related complications and no case of coracoid graft osteolysis. Conclusions Mini-open Latarjet with graft fixation with Arthrex mini-plate provides satisfactory outcome in patients who require reoperation due to dramatic bone loss and failed soft tissue reconstruction. The modified incision improves exposure enabling plate fixation and the secure fixation accelerates rehabilitation. PMID:26908972

  14. 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

  15. 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

  16. High-Speed Ion Flow, Substorm Current Wedge, and Multiple Pi 2 Pulsations

    DTIC Science & Technology

    2007-11-02

    5.76 65.8 22.96 -20.5 03 6. 66 23 -2 20 3 .5 .19 D.6 Figure 12. Magnetic field data measured on the ISEE 1 satellite in the GSE...ISMC-TR-99-04 AEROSPACE REPORT NO. TR-99(8570)- 3 iHigh-Speed Ion Flow, Substorm Current Wedge, land Multiple Pi 2 Pulsations >0 December 1998...and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20S03. 1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 20 December 1998 3

  17. Phase-Shift Master-Slave Mechanisms for High Angular-Speed Wedge-Prism Systems

    NASA Astrophysics Data System (ADS)

    Chappuis, Olivier; Clavel, Reymond

    2013-02-01

    Laser micro-machining requires high dynamic laser spot trajectory and accuracy to control the laser beam scanning. A well-known technique to scan a laser beam over a specimen is to use a pair of wedge-prisms. However, it is difficult to master-slave the phase-shift between two rotating prisms at high angular-speed. We present here two drive mechanisms that decouple the phase-shift control and the angular-speed control. These mechanisms simplify the required control architecture and are suitable to achieve a high-dynamic trajectory. These concepts are based on differential timing belts and gears mechanisms that modify the phase-shift between the prisms without interrupting the rotation. This article focuses on the kinematic and mechanical design aspects of such mechanisms.

  18. Optimal clinical implementation of the Siemens virtual wedge.

    PubMed

    Walker, C P; Richmond, N D; Lambert, G D

    2003-01-01

    Installation of a modern high-energy Siemens Primus linear accelerator at the Northern Centre for Cancer Treatment (NCCT) provided the opportunity to investigate the optimal clinical implementation of the Siemens virtual wedge filter. Previously published work has concentrated on the production of virtual wedge angles at 15 degrees, 30 degrees, 45 degrees, and 60 degrees as replacements for the Siemens hard wedges of the same nominal angles. However, treatment plan optimization of the dose distribution can be achieved with the Primus, as its control software permits the selection of any virtual wedge angle from 15 degrees to 60 degrees in increments of 1 degrees. The same result can also be produced from a combination of open and 60 degrees wedged fields. Helax-TMS models both of these modes of virtual wedge delivery by the wedge angle and the wedge fraction methods respectively. This paper describes results of timing studies in the planning of optimized patient dose distributions by both methods and in the subsequent treatment delivery procedures. Employment of the wedge fraction method results in the delivery of small numbers of monitor units to the beam's central axis; therefore, wedge profile stability and delivered dose with low numbers of monitor units were also investigated. The wedge fraction was proven to be the most efficient method when the time taken for both planning and treatment delivery were taken into consideration, and is now used exclusively for virtual wedge treatment delivery in Newcastle. It has also been shown that there are no unfavorable dosimetric consequences from its practical implementation.

  19. Biomechanical Analysis of a Novel Wedge Locking Plate in a Porcine Tibial Model

    PubMed Central

    Ha, Jeong-Ku; Yeom, Chul Hyun; Jang, Ho Su; Song, Han Eui; Lee, Sung Jae; Kim, Kang Hee; Chung, Kyu Sung; Bhat, Mahendar Gururaj

    2016-01-01

    Background The purpose of this study was to analyze biomechanical properties of a novel wedge locking plate in medial open wedge high tibial osteotomy (OWHTO) in a porcine tibial model. Methods A uniform 8-mm OWHTO was performed in 12 porcine tibiae. Six of them were subsequently fixed with the plate without a wedge, whereas the other 6 were additionally reinforced with a metal wedge of 8 mm. Biomechanical properties (stiffness, displacement of the osteotomy gap, and failure load) were evaluated under axial load. The different modes of failure were also investigated. Results The plate showed an axial stiffness of 2,457 ± 450 N/mm with a wedge and 1,969 ± 874 N/mm without a wedge. The maximum failure load was 5,380 ± 952 N with a wedge and 4,354 ± 607 N without a wedge. The plate with a wedge had a significantly greater failure load and significantly less displacement of medial gap at failure than that without a wedge (p = 0.041 and p = 0.002, respectively). The axial stiffness was not different between the two types of fixation. Most failures were caused by lateral cortex breakage and there was no implant failure. Conclusions The novel wedge locking plate showed excellent biomechanical properties and an additional wedge provided significant improvement. This plate can be a good fixation method for OWHTO. PMID:27904718

  20. Opening-wedge osteotomy, allografting with dual buttress plate fixation for severe genu recurvatum caused by partial growth arrest of the proximal tibial physis: a case report.

    PubMed

    Chen, Liang-Chin; Chan, Yi-Sheng; Wang, Ching-Jen

    2004-07-01

    Injuries to the proximal tibial physis are among the least common epiphyseal injuries. We present a case of severe genu recurvatum deformity (45 degrees) with leg length discrepancy (4 cm) following a neglected proximal tibial physeal injury incurred 6 years previously. The 16-year-old patient was successfully treated by open-wedge osteotomy, allograft reconstruction, and dual buttress plate fixation. At 3 years' follow-up, the patient was asymptomatic, fully active with a full range of motion (0 - 140 degrees) of the leg, and equal leg lengths. There were no signs of genu recurvatum clinically.

  1. 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

  2. The role of subducting bathymetric highs on the oceanic crust to deformation of accretionary wedge and earthquake segmentation in the Java forearc

    NASA Astrophysics Data System (ADS)

    Singh, S. C.; Mukti, M.; Deighton, I.

    2014-12-01

    Stratigraphic and structural observations of newly acquired seismic reflection data along the offshore south Java reveal the structural style of deformation along the forearc and the role of subducting bathymetric highs to the morphology of the forearc region. The forearc region can be divided in to two major structural units: accretionary wedge and forearc and forearc basin where a backthrust marks the boundary between the accretionary wedge and the forearc basin sediments. The continuous compression in the subduction zone has induced younger landward-vergent folds and thrusts within the seaward margin of the forearc basin sediments, which together with the backthrust is referred as the Offshore South Java Fault Zone (OSJFZ), representing the growth of the accretionary wedge farther landward. Seaward-vergent imbricated thrusts have deformed the sediments in the accretionary wedge younging seaward, and have developed fold-thrust belts in the accretionary wedge toward trench. Together with the backthrusts, these seaward-vergent thrusts characterize the growth of accretionary wedge in South of Java trench. Based on these new results, we suggest that accretionary wedge mechanic is not the first order factor in shaping the morphology of the accretionary wedge complex. Instead the subducting bathymetric highs play the main role in shaping the forearc that are manifested in the uplift of the forearc high and intense deformation along the OSJFZ. These subducting highs also induce compression within the accretionary sediments, evident from landward deflection of the subduction front at the trench and inner part of accretionary wedge in the seaward margin of the forearc basin. Intense deformation is also observed on the seaward portion of the accretionary wedge area where the bathymetric highs subducted. We suggest that these subducted bathymetric features define the segment boundaries for megathrust earthquakes, and hence reducing the maximum size of the earthquakes in the

  3. 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.

  4. 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

  5. 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

  6. High-enthalpy shock/boundary-layer interaction on a double wedge

    NASA Astrophysics Data System (ADS)

    Davis, Jean-Paul

    1999-11-01

    Interaction between a shock wave and a boundary layer at a compression corner can produce a region of separated flow. The length of separation is important in determining aerodynamic forces, and the heat transfer at reattachment is important for the design of thermal protection systems. The effects of high-enthalpy flow on these phenomenon, particularly separation length, are not well known. Experiments to measure separation length and reattachment heating are performed in the T5 Hypervelocity Shock Tunnel using nitrogen test gas and a double-wedge geometry which allows greater control over local flow conditions at separation and, at high incidence angle, may produce real-gas effects due to dissociation behind the leading shock. Local external flow conditions were found by computational reconstruction of the inviscid nonequilibrium flow field.Application of results from asymptotic theory to a simple model for separation leads to a new scaling parameter which approximately accounts for wall temperature effects on separation length for a laminar nonreacting boundary layer and extends previous results to arbitrary viscosity law. A. classification is introduced which divides mechanisms for real-gas effects into those acting internal and external to viscous regions of the flow, with internal mechanisms further subdivided into those arising upstream and downstream of separation. Application of the ideal dissociating gas model to a scaling law based on local external flow parameters and a nonreacting boundary layer shows that external mechanisms due to dissociation decrease separation length at low incidence but depend on the free-stream dissociation at high incidence, and have only a small effect on peak heating. A limited numerical study of reacting boundary layers shows that internal mechanisms due to recombination in the upstream boundary layer cause a slight decrease in separation length and a large increase in heat flux relative to a nonreacting boundary layer with

  7. Wedged multilayer Laue Lens.

    SciTech Connect

    Conley, R.; Liu, C.; Qian, J.; Kewish, C. M.; Macrander, A. T.; Yan, H.; Kang, H. C.; Maser, J.; Stephenson, G. B.

    2008-05-01

    A multilayer Laue lens (MLL) is an x-ray focusing optic fabricated from a multilayer structure consisting of thousands of layers of two different materials produced by thin-film deposition. The sequence of layer thicknesses is controlled to satisfy the Fresnel zone plate law and the multilayer is sectioned to form the optic. An improved MLL geometry can be created by growing each layer with an in-plane thickness gradient to form a wedge, so that every interface makes the correct angle with the incident beam for symmetric Bragg diffraction. The ultimate hard x-ray focusing performance of a wedged MLL has been predicted to be significantly better than that of a nonwedged MLL, giving subnanometer resolution with high efficiency. Here, we describe a method to deposit the multilayer structure needed for an ideal wedged MLL and report our initial deposition results to produce these structures.

  8. High-energy rate forgings of wedges. Characterization of processing conditions

    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.

  9. 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.

  10. Base pressure associated with incompressible flow past wedges at high Reynolds numbers

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    A model is suggested to study the viscid-inviscid interaction associated with steady incompressible flow past wedges of arbitrary angles. It is shown from this analysis that the determination of the nearly constant pressure (base pressure) prevailing within the near wake is really the heart of the problem and this pressure can only be determined from these interactive considerations. The basic free streamline flow field is established through two discrete parameters which should adequately describe the inviscid flow around the body and the wake. The viscous flow processes such as boundary-layer buildup along the wedge surface, jet mixing, recompression, and reattachment which occurs along the region attached to the inviscid flow in the sense of the boundary-layer concept, serve to determine the aforementioned parameters needed for the establishment of the inviscid flow. It is found that the point of reattachment behaves as a saddle point singularity for the system of equations describing the viscous recompression process. Detailed results such as the base pressure, pressure distributions on the wedge surface, and the wake geometry as well as the influence of the characteristic Reynolds number are obtained. Discussion of these results and their comparison with the experimental data are reported.

  11. 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.

  12. 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

  13. Grounding-zone wedges (GZWs) on high-latitude continental margins

    NASA Astrophysics Data System (ADS)

    Batchelor, Christine; Dowdeswell, Julian

    2014-05-01

    inferred for GZWs on the Greenland, Norwegian, Canadian and Barents Sea margins. However, no significant relationship between GZW length and thickness exists for the GZWs described from the Antarctic margin. GZWs typically possess a semi-transparent to chaotic acoustic character, which reflects the delivery of diamictic subglacial debris. Many GZWs contain low-amplitude, seaward-dipping internal reflections, which indicate sediment progradation and wedge-growth through continued delivery of basal sediments from the flow of active ice. The formation of GZWs is inferred to require high rates of sediment delivery to a relatively stable, fast-flowing ice margin. Ice-margin stabilisation, and consequently GZW formation, is dependent on a number of factors, including the ice-sheet mass balance, sea-level fluctuations, and the rate of inland-ice delivery to the grounding-zone. GZWs may be formed preferentially by glaciers with termini ending as floating ice shelves, which restrict vertical accommodation space and prevent the build-up of high-amplitude moraine ridges. The basal topography of the continental shelf can also act as a control on GZW formation. The majority of high-latitude GZWs are located at topographic or lateral pinning points within cross-shelf troughs, which encourage ice-margin stabilisation through reducing iceberg calving and increasing basal and lateral drag.

  14. 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.

  15. 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.

  16. Optimized dynamic rotation with wedges.

    PubMed

    Rosen, I I; Morrill, S M; Lane, R G

    1992-01-01

    Dynamic rotation is a computer-controlled therapy technique utilizing an automated multileaf collimator in which the radiation beam shape changes dynamically as the treatment machine rotates about the patient so that at each instant the beam shape matches the projected shape of the target volume. In simple dynamic rotation, the dose rate remains constant during rotation. For optimized dynamic rotation, the dose rate is varied as a function of gantry angle. Optimum dose rate at each gantry angle is computed by linear programming. Wedges can be included in the optimized dynamic rotation therapy by using additional rotations. Simple and optimized dynamic rotation treatment plans, with and without wedges, for a pancreatic tumor have been compared using optimization cost function values, normal tissue complication probabilities, and positive difference statistic values. For planning purposes, a continuous rotation is approximated by static beams at a number of gantry angles equally spaced about the patient. In theory, the quality of optimized treatment planning solutions should improve as the number of static beams increases. The addition of wedges should further improve dose distributions. For the case studied, no significant improvements were seen for more than 36 beam angles. Open and wedged optimized dynamic rotations were better than simple dynamic rotation, but wedged optimized dynamic rotation showed no definitive improvement over open beam optimized dynamic rotation.

  17. High strain gradient plasticity associated with wedge indentation into face-centered cubic single crystals: Geometrically necessary dislocation densities

    NASA Astrophysics Data System (ADS)

    Kysar, Jeffrey W.; Gan, Yong X.; Morse, Timothy L.; Chen, Xi; Jones, Milton E.

    2007-07-01

    Experimental studies on indentation into face-centered cubic (FCC) single crystals such as copper and aluminum were performed to reveal the spatially resolved variation in crystal lattice rotation induced due to wedge indentation. The crystal lattice curvature tensors of the indented crystals were calculated from the in-plane lattice rotation results as measured by electron backscatter diffraction (EBSD). Nye's dislocation density tensors for plane strain deformation of both crystals were determined from the lattice curvature tensors. The least L2-norm solutions to the geometrically necessary dislocation densities for the case in which three effective in-plane slip systems were activated in the single crystals associated with the indentation were determined. Results show the formation of lattice rotation discontinuities along with a very high density of geometrically necessary dislocations.

  18. Penetrating eye injury from a metal wedge.

    PubMed

    Kozielec, G F; To, K

    1999-01-01

    The authors describe a patient with a penetrating ocular injury from a metal wedge, a common hand tool used by road service technicians for the purpose of opening a locked car door. The patient had a penetrating eye injury from a metal wedge when its sharp end released from a car door lock and retracted upward, striking the right eye. No report exists of ocular injury using a metal wedge for its intended purpose of opening a car door lock. The use of polycarbonate lenses might afford some protection.

  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. Evaluating the dose to the contralateral breast when using a dynamic wedge versus a regular wedge.

    PubMed

    Weides, C D; Mok, E C; Chang, W C; Findley, D O; Shostak, C A

    1995-01-01

    The incidence of secondary cancers in the contralateral breast after primary breast irradiation is several times higher than the incidence of first time breast cancer. Studies have shown that the scatter radiation to the contralateral breast may play a large part in the induction of secondary breast cancers. Factors that may contribute to the contralateral breast dose may include the use of blocks, the orientation of the field, and wedges. Reports have shown that the use of regular wedges, particularly for the medial tangential field, gives a significantly higher dose to the contralateral breast compared to an open field. This paper compares the peripheral dose outside the field using a regular wedge, a dynamic wedge, and an open field technique. The data collected consisted of measurements taken with patients, solid water and a Rando phantom using a Varian 2300CD linear accelerator. Ion chambers, thermoluminescent dosimeters (TLD), diodes, and films were the primary means for collecting the data. The measurements show that the peripheral dose outside the field using a dynamic wedge is close to that of open fields, and significantly lower than that of regular wedges. This information indicates that when using a medial wedge, a dynamic wedge should be used.

  2. Geometry and kinematics of extensional structural wedges

    NASA Astrophysics Data System (ADS)

    Gui, Baoling; He, Dengfa; Zhang, Yongsheng; Sun, Yanpeng; Huang, Jingyi; Zhang, Wenjun

    2017-03-01

    Structural wedges in the compressive environment have been recognized and studied in different locations. However, extension structural wedges are less well-understood. Based on the normal fault-bend folding theory and inclined shear model, this paper quantitatively analyses deformations related to extensional structural wedges and builds a series of geometric models for them. An extensional structural wedge is a fault-block held by two or more normal faults, the action of which would fold its overlying strata. Extensional structural wedges of different shapes will lead to different deformation results for the overlying strata, and this paper illustrates both the triangular and quadrangular wedges and their related deformations. This paper also discusses differences between the extensional structural wedges and the normal fault-bend-folding. By analysing two seismic sections from Langfang-Gu'an Sag, East China, this paper provides two natural examples of the triangular and quadrangular extensional structural wedges, where the models can reasonably explain the overlying distinct highs and lows without obvious faults. The establishment of a geometric model of extensional structural wedges can provide reference and theoretical bases for future quantitative analysis of deformations in the extensional environment.

  3. High efficient coupling between wedged-shaped fiber and planar lightwave circuit chip using gradient refractive-index media

    NASA Astrophysics Data System (ADS)

    Liu, Xu; Qu, Shuting; Xiao, Jinbiao; Sun, Xiaohan

    2006-10-01

    Planar lightwave circuit (PLC) chips based on III-V semiconductor MQW rib waveguide promise to be not only a solution to information access, but also direct the issues of bandwidth, pin count, reliability and complexity. Nanopositioning and precision alignment addresses vital importance in high-efficient connectivity between PLC chips and fiber arrays. Refractive-index mismatching between fused silica and III-V compound is one of the most serious problem which remains unsolved on one hand as well as mode field mismatching which can be mitigated in other hand through gradient geometry structure such as tapered spot size converter (SSC) and specialty fibers such as wedge-shaped fiber (WSF). Spherical gradient refractive-index (SGRIN) media intervened between WSF and MQW rib waveguide is put forward. The GRIN media virtually eliminates the reflection losses associated with the fused silica-air interface and III-V semiconductor-air interface. The beam spot emitted from WSF are observed by digital camera and the fundamental mode of MQW rib waveguide was calculated out. Lightwave propagation and mode field evolution in the WSF-SGRIN-PLC system is simulated by FDTD method with the coupling loss of 8.54dB at a wavelength of 1.55μm. An LED signal is injected into WSF, transmitted along GRIN media and PLC waveguide and output through single mode fiber (SMF). Optical power meter-based measurement verifies the whole system coupling loss to be consistent with the numeric estimation. The approach provides an experimental prototype for coupling and packaging technique of integrated photonic devices, hence supplying foundation for photonic network.

  4. 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.

  5. 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.

  6. High-resolution 3D numerical modeling of thrust wedges: Influence of décollement strength on transfer zones

    NASA Astrophysics Data System (ADS)

    Ruh, Jonas B.; Gerya, Taras; Burg, Jean-Pierre

    2013-04-01

    mechanics and dynamics of thin-skinned compressible thrust wedges with prescribed offsets in the backstop, i.e., transfer zones, are investigated using a three-dimensional finite difference numerical model with a visco-brittle/plastic rheology. The main questions addressed are as follows: (i) What is the influence of the initial length of the backstop offset and (ii) what is the effect of the frictional strength of the main décollement on the structural evolution of the brittle wedges along such transfer zones? Results show that the shorter the backstop offset, the earlier these two thrust planes connect, forming a curved frontal thrust along the entire width of the model. Younger, in-sequence thrusts are formed parallel to this curved shape. Long backstop offsets produce strongly curved thrust faults around the indenting corner. Simulations with a weak basal friction evolve toward almost linear frontal thrusts orthogonal to the bulk shortening direction. Increased basal drag in models with a strong décollement favors propagation of the backstop offset into a transfer zone up to the frontal thrust. These simulations revealed that surface tapers of the wedge in front of the backstop promontory are larger than what the critical wedge theory predicts, whereas the tapers on the other side of the transfer zone are smaller than analytical values. This difference is amplified with increasing length of the backstop offset and/or strength of the décollement. Modeled surface elevation schemes reproduce well the topographic patterns of natural orogenic systems such as the topographic low along the Minab-Zendan transform/transfer fault between the Zagros and Makran.

  7. The Substorm Current Wedge Revisited

    NASA Astrophysics Data System (ADS)

    Kepko, Larry; McPherron, Robert; Apatenkov, Sergey; Baumjohann, Wolfgang; Birn, Joachim; Lester, Mark; Nakamura, Rumi; Pulkkinen, Tuija; Sergeev, Victor

    2015-04-01

    Almost 40 years ago the concept of the substorm current wedge was developed to explain the magnetic signatures observed on the ground and in geosynchronous orbit during substorm expansion. In the ensuing decades new observations, including radar and low-altitude spacecraft, MHD simulations, and theoretical considerations have tremendously advanced our understanding of this system. The AMPTE/IRM, THEMIS and Cluster missions have added considerable observational knowledge, especially on the important role of fast flows in producing the stresses that generate the substorm current wedge. Recent detailed, multi-spacecraft, multi-instrument observations both in the magnetosphere and in the ionosphere have brought a wealth of new information about the details of the temporal evolution and structure of the current system. In this paper, we briefly review recent in situ and ground-based observations and theoretical work that have demonstrated a need for an update of the original picture. We present a revised, time-dependent picture of the substorm current wedge that follows its evolution from the initial substorm flows through substorm expansion and recovery, and conclude by identifying open questions.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Fastening of a High-Strength Composite rod with a Splitted and Wedged end in a Potted Anchor 1. Experimental Investigation

    NASA Astrophysics Data System (ADS)

    Arnautov, A. K.; Terrasi, G. P.; Kulakov, V. L.; Portnov, G. G.

    2014-01-01

    The effectiveness of fastening of high-strength unidirectional CFRP/epoxy rods in potted anchors was investigated experimentally. The rods had splitted ends, in which duralumin wedges were glued. The experiments, performed for three types of contact between the composite rods and the potted material, showed that the most effective were full adhesion and adhesion-friction contacts, when the maximum load-carrying capacity of CFRP rods under tension could be reached. The full friction contact was ineffective because of the shear failure of CFRP rods inside the anchorage zone.

  13. Seismic rupture propagation beneath potential landslide wedge

    NASA Astrophysics Data System (ADS)

    Sakaguchi, A.; Kawamura, K.

    2011-12-01

    During 2011 Tohoku earthquake (Mw 9.0), much larger slip and tsunami occurred than expectation at outer-wedge (toe of the trench landward slope) of Japan trench (eg. Ide et al., 2011). Similarly, outer-wedge deformation was pointed out in northern segment of 1986 Meiji-Sanriku earthquake (Ms 7.2), and it was discussed that earthquake-related landslide induced large tsunami (eg. Kanamori, 1972; Tanioka and Satake, 1996). Many landslides and normal faults, potential tsunami genesis, are developed at outer-wedge of Japan trench (Henry et al., 1989). Some steep normal-faults turn to horizon at deep portion, and land sliding may be prevented by basal friction. If seismic rupture propagates to basal fault of the outer-wedge, triggered gravity collapse will enlarge deformation of the outer-wedge to cause large tsunamis. It was considered that seismogenic fault locks at deep portion under inner-wedge of the plate subduction zone, and outer-wedge was classified into aseismic zone classically. Seismic rupture propagation to outer-wedge is still uncertain. Seismic slip at the outer-wedge was found from the drilled core during IODP Nankai trough seismogenic zone drilling project (NanTroSEIZE) in Nankai trough, southwest Japan. Samples were obtained from the frontal thrust (438 mbsf), which connects the deep plate boundary to the seafloor at the toe of the accretionary wedge, and from a megasplay fault (271 mbsf) that branches from the plate boundary décollement. Higher vitrinite reflectance of 0.57 % and 0.37 % than the host rock of 0.24 % were found at splay and plate boundary faults zones respectively. These correspond with 300-400 °C and > 20°C of host rock. Local high temperature zone less than several cm thick may be caused by frictional shear heat at fault zone (Sakaguchi, et al., 2011). Shear velocity and durations can be estimated from thermal property of the sediment and distribution of the vitrinite anomaly (Hamada et al., 2011). This result shows that seismic

  14. 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.

  15. Fastening of a High-Strength Composite Rod with a Splitted and Wedged End in a Potted Anchor 2. Finite-Element Analysis

    NASA Astrophysics Data System (ADS)

    Kulakov, V. L.; Terrasi, G. P.; Arnautov, A. K.; Portnov, G. G.; Kovalov, A. O.

    2014-03-01

    A finite element analysis is carried out to determine the stress-strain state of anchors for round rods made of a high- modulus, high-strength unidirectional carbon-fiber reinforced plastic. The rods have splitted ends in which Duralumin wedges are glued. Three types of contact between the composite rods and a potted epoxy compound are considered: adhesion, adhesion-friction, and friction ones. The corresponding three-dimensional problems in the elastic statement are solved by the finite-element method (FEM) with account of nonlinear Coulomb friction. An analysis of stresses on the surface of the composite rod revealed the locations of high concentrations of operating stresses. The results of FEM calculations agree with experimental data.

  16. Substorm Current Wedge Revisited

    NASA Astrophysics Data System (ADS)

    Kepko, L.; McPherron, R. L.; Amm, O.; Apatenkov, S.; Baumjohann, W.; Birn, J.; Lester, M.; Nakamura, R.; Pulkkinen, T. I.; Sergeev, V.

    2015-07-01

    Almost 40 years ago the concept of the substorm current wedge was developed to explain the magnetic signatures observed on the ground and in geosynchronous orbit during substorm expansion. In the ensuing decades new observations, including radar and low-altitude spacecraft, MHD simulations, and theoretical considerations have tremendously advanced our understanding of this system. The AMPTE/IRM, THEMIS and Cluster missions have added considerable observational knowledge, especially on the important role of fast flows in producing the stresses that generate the substorm current wedge. Recent detailed, multi-spacecraft, multi-instrument observations both in the magnetosphere and in the ionosphere have brought a wealth of new information about the details of the temporal evolution and structure of the current system. While the large-scale picture remains valid, the new details call for revision and an update of the original view. In this paper we briefly review the historical development of the substorm current wedge, review recent in situ and ground-based observations and theoretical work, and discuss the current active research areas. We conclude with a revised, time-dependent picture of the substorm current wedge that follows its evolution from the initial substorm flows through substorm expansion and recovery.

  17. 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.

  18. Opening the high-energy frontier

    SciTech Connect

    Quigg, C.

    1988-12-01

    I review the scientific motivation for an experimental assault on the 1-TeV scale, elaborating the idea of technicolor as one interesting possibility for what may be found there. I then summarize some of the discovery possibilities opened by a high-luminosity, multi-TeV proton-proton collider. After a brief resume of the experimental environment anticipated at the SSC, I report on the status of the SSC R D effort and discuss the work to be carried out over the course of the next year. 37 refs., 10 figs., 1 tab.

  19. High-torque open-end wrench

    NASA Technical Reports Server (NTRS)

    Giandomenico, A.; Dame, J. M.; Behimer, H. (Inventor)

    1978-01-01

    A wrench is described that is usable where limited access normally requires an open-end wrench, but which has substantially the high-torque capacity and small radial clearance characteristics of a closed-end wrench. The wrench includes a sleeve forming a nut-engageable socket with a gap in its side, and an adaptor forming a socket with a gap in its side, the adaptor closely surrounding the sleeve and extending across the gap in the sleeve. The sleeve and adaptor have surfaces that become fully engaged when a wrench handle is applied to the adaptor to turn it so as to tighten a nut engaged by the sleeve.

  20. Shock detachment from curved wedges

    NASA Astrophysics Data System (ADS)

    Mölder, S.

    2017-03-01

    Curved shock theory is used to show that the flow behind attached shocks on doubly curved wedges can have either positive or negative post-shock pressure gradients depending on the freestream Mach number, the wedge angle and the two wedge curvatures. Given enough wedge length, the flow near the leading edge can choke to force the shock to detach from the wedge. This local choking can preempt both the maximum deflection and the sonic criteria for shock detachment. Analytical predictions for detachment by local choking are supported by CFD results.

  1. Recognition and characterization of networks of water bodies in the Arctic ice-wedge polygonal tundra using high-resolution satellite imagery

    NASA Astrophysics Data System (ADS)

    Skurikhin, A. N.; Gangodagamage, C.; Rowland, J. C.; Wilson, C. J.

    2013-12-01

    Arctic lowland landscapes underlain by permafrost are often characterized by polygon-like patterns such as ice-wedge polygons outlined by networks of ice wedges and complemented with polygon rims, troughs, shallow ponds and thermokarst lakes. Polygonal patterns and corresponding features are relatively easy to recognize in high spatial resolution satellite imagery by a human, but their automated recognition is challenging due to the variability in their spectral appearance, the irregularity of individual trough spacing and orientation within the patterns, and a lack of unique spectral response attributable to troughs with widths commonly between 1 m and 2 m. Accurate identification of fine scale elements of ice-wedge polygonal tundra is important as their imprecise recognition may bias estimates of water, heat and carbon fluxes in large-scale climate models. Our focus is on the problem of identification of Arctic polygonal tundra fine-scale landscape elements (as small as 1 m - 2 m width). The challenge of the considered problem is that while large water bodies (e.g. lakes and rivers) can be recognized based on spectral response, reliable recognition of troughs is more difficult. Troughs do not have unique spectral signature, their appearance is noisy (edges are not strong), their width is small, and they often form connected networks with ponds and lakes, and thus they have overlapping spectral response with other water bodies and surrounding non-water bodies. We present a semi-automated approach to identify and classify Arctic polygonal tundra landscape components across the range of spatial scales, such as troughs, ponds, river- and lake-like objects, using high spatial resolution satellite imagery. The novelty of the approach lies in: (1) the combined use of segmentation and shape-based classification to identify a broad range of water bodies, including troughs, and (2) the use of high-resolution WorldView-2 satellite imagery (with resolution of 0.6 m) for this

  2. Sharp Thermal Transition in the Forearc Mantle Wedge as a Consequence of Nonlinear Mantle Wedge Flow

    NASA Astrophysics Data System (ADS)

    Wada, I.; Wang, K.; Jiangheng, H.

    2009-12-01

    A sharp landward increase in seismic attenuation over a few tens of kilometres distance in the forearc mantle wedge has been reported for a number of subduction zones, including Alaska, Costa Rica, central Andes, Hikurangi, and NE Japan. The low attenuation in the wedge nose is commonly interpreted as to indicate a cold state, and the high attenuation further landward to indicate high temperature and/or partial melting. Beneath the arc, the high temperature at shallow depths may be caused by transient melt migration, but at larger depths the mantle wedge must be hot enough to generate melt. Thus, the landward change in the thermal state of the forearc mantle wedge is large and sharp. We use a two-dimensional steady-state thermal model and the subduction-interface weakening approach of Wada et al. (2008) to investigate how slab-driven mantle wedge flow controls the thermal transition. We observe that the sharpness of the transition increases with the increasing nonlinearity of the flow system. In an isoviscous mantle wedge with a uniform interface strength, there is no spontaneous transition in the flow and thermal fields. In a diffusion-creep mantle wedge, even with a uniform interface strength, the strong temperature dependence of the mantle rheology always results in full slab-mantle decoupling along the weakened part of the interface and hence complete stagnation of the overlying mantle, giving rise to a cold wedge nose that does not participate in the wedge flow. On the other hand, the interface immediately downdip of the zone of decoupling is fully coupled, and the overlying mantle is driven to flow at a rate compatible with the subduction rate. The flow system thus shows a bimodal behaviour. In a dislocation-creep mantle wedge, its stress-dependence results in an additional feedback effect, making the bimodal behaviour more pronounced than in the diffusion-creep mantle wedge, with an abrupt change from decoupling to coupling along the subduction interface

  3. Coherently Opening a High-Q Cavity

    NASA Astrophysics Data System (ADS)

    Tufarelli, Tommaso; Ferraro, Alessandro; Serafini, Alessio; Bose, Sougato; Kim, M. S.

    2014-04-01

    We propose a general framework to effectively "open" a high-Q resonator, that is, to release the quantum state initially prepared in it in the form of a traveling electromagnetic wave. This is achieved by employing a mediating mode that scatters coherently the radiation from the resonator into a one-dimensional continuum of modes such as a waveguide. The same mechanism may be used to "feed" a desired quantum field to an initially empty cavity. Switching between an open and "closed" resonator may then be obtained by controlling either the detuning of the scatterer or the amount of time it spends in the resonator. First, we introduce the model in its general form, identifying (i) the traveling mode that optimally retains the full quantum information of the resonator field and (ii) a suitable figure of merit that we study analytically in terms of the system parameters. Then, we discuss two feasible implementations based on ensembles of two-level atoms interacting with cavity fields. In addition, we discuss how to integrate traditional cavity QED in our proposal using three-level atoms.

  4. 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.

  5. Penetrable Wedge Analysis

    DTIC Science & Technology

    1993-08-03

    F -A276 232 GE F Formpproved P-W-=nQb,3;t- OBM No. 0704 -0188 foI rll it 1 Ilthisl buridllenli 1i to :iudrrg th ftirnu reviwing Wwtru"t.Of S.aching...geometries. (2) Numerical " solutions" are still proliferating, but are too messy and remoxed from the physics to offer any important insight into the wave...mathematical solution of the impedance boundary wedge. III. PHYSICAL IMPEDANCE BOUNDARY CONDITION The coupled difference equations (14), (17), and (18) on page

  6. Tumor Targeting, Trifunctional Dendritic Wedge

    PubMed Central

    2015-01-01

    We report in vitro and in vivo evaluation of a newly designed trifunctional theranostic agent for targeting solid tumors. This agent combines a dendritic wedge with high boron content for boron neutron capture therapy or boron MRI, a monomethine cyanine dye for visible-light fluorescent imaging, and an integrin ligand for efficient tumor targeting. We report photophysical properties of the new agent, its cellular uptake and in vitro targeting properties. Using live animal imaging and intravital microscopy (IVM) techniques, we observed a rapid accumulation of the agent and its retention for a prolonged period of time (up to 7 days) in fully established animal models of human melanoma and murine mammary adenocarcinoma. This macromolecular theranostic agent can be used for targeted delivery of high boron load into solid tumors for future applications in boron neutron capture therapy. PMID:25350602

  7. 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.

  8. 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…

  9. 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. .

  10. Geochemistry of rare high-Nb basalt lavas: Are they derived from a mantle wedge metasomatised by slab melts?

    NASA Astrophysics Data System (ADS)

    Hastie, Alan R.; Mitchell, Simon F.; Kerr, Andrew C.; Minifie, Matthew J.; Millar, Ian L.

    2011-09-01

    Compositionally, high-Nb basalts are similar to HIMU (high U/Pb) ocean island basalts, continental alkaline basalts and alkaline lavas formed above slab windows. Tertiary alkaline basaltic lavas from eastern Jamaica, West Indies, known as the Halberstadt Volcanic Formation have compositions similar to high-Nb basalts (Nb > 20 ppm). The Halberstadt high-Nb basalts are divided into two compositional sub-groups where Group 1 lavas have more enriched incompatible element concentrations relative to Group 2. Both groups are derived from isotopically different spinel peridotite mantle source regions, which both require garnet and amphibole as metasomatic residual phases. The Halberstadt geochemistry demonstrates that the lavas cannot be derived by partial melting of lower crustal ultramafic complexes, metasomatised mantle lithosphere, subducting slabs, continental crust, mantle plume source regions or an upper mantle source region composed of enriched and depleted components. Instead, their composition, particularly the negative Ce anomalies, the high Th/Nb ratios and the similar isotopic ratios to nearby adakite lavas, suggests that the Halberstadt magmas are derived from a compositionally variable spinel peridotite source region(s) metasomatised by slab melts that precipitated garnet, amphibole, apatite and zircon. It is suggested that high-Nb basalts may be classified as a distinct rock type with Nb > 20 ppm, intraplate alkaline basalt compositions, but that are generated in subduction zones by magmatic processes distinct from those that generate other intraplate lavas.

  11. 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

    2015-09-09

    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.

  12. Bouncing and bursting in a wedge

    NASA Astrophysics Data System (ADS)

    Reyssat, Etienne; Cohen, Caroline; Quere, David

    2015-11-01

    Placed into an inhomogeneous confined medium, non-wetting drops tend to be expelled from the tightest regions, where their contact with the walls would be maximized. They preferentially explore more open areas which are favorable from the point of view of capillary energy. Following this principle, one may thus use the geometry of confined environments to control fluid droplets in various ways : displacing, filtering, fragmenting... In this communication, we present experimental results on the dynamics of Leidenfrost drops launched into a wedge formed by two quasi-horizontal glass plates. Influenced by the gradient of confinement, these non-wetting liquid pucks approach the apex of the wedge to a minimal distance where they bounce back. At higher impact velocity, we observe that drops tend to penetrate deeper into the wedge but often burst into a large number of small fragments. We also discuss ways to control the deviation of droplets from their initial trajectory. We propose scaling law analyses to explain the characteristics of the observed bouncing and bursting phenomena.

  13. 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

  14. 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.

  15. 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.

  16. New machining and testing method of large angle infrared wedge mirror parts

    NASA Astrophysics Data System (ADS)

    Su, Ying; Guo, Rui; Zhang, Fumei; Zhang, Zheng; Liu, Xuanmin; Zengqi, Xu; Li, Wenting; Zhang, Feng

    2016-10-01

    Large angle wedge parts were widely used in the optical system that was used for achieving a wide range of scanning. Due to the parts having the characteristic of large difference in the thickness of both ends and high density, the accuracy of the wedge angle was hard to ensure to reach second level in optical processing. Generally, wedge mirror angle was measured by contact comparison method which was easy to damage the surface. In view of the existence of two practical problems, in this paper, based on theoretical analysis, by taking three key measures that were the accurate positioning for the central position of the large angle wedge part, the accuracy control of angle precision machined of wedge mirror and fast and non destructive laser assisted absolute measurement of large angle wedge, the qualified rate of parts were increased to 100%, a feasible, controllable and efficient process route for large angle infrared wedge parts was found out.

  17. Wedge Heat-Flux Indicators for Flash Thermography

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay M.

    2003-01-01

    Wedge indicators have been proposed for measuring thermal radiation that impinges on specimens illuminated by flash lamps for thermographic inspection. Heat fluxes measured by use of these indicators would be used, along with known thermal, radiative, and geometric properties of the specimens, to estimate peak flash temperatures on the specimen surfaces. These indicators would be inexpensive alternatives to high-speed infrared pyrometers, which would otherwise be needed for measuring peak flash surface temperatures. The wedge is made from any suitable homogenous material such as plastic. The choice of material is governed by the equation given. One side of the wedge is covered by a temperature sensitive compound that decomposes irreversibly when its temperature exceeds a rated temperature (T-rated). The uncoated side would be positioned alongside or in place of the specimen and exposed to the flash, then the wedge thickness at the boundary between the white and blackened portions measured.

  18. 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.

  19. Geophysical Surveys for Detecting Distribution and Shape of Ice Wedges

    NASA Astrophysics Data System (ADS)

    Watanabe, T.; Matsuoka, N.; Ikeda, A.

    2006-12-01

    Recent development of applied geophysical methods has shown detailed structure in various periglacial features. However, these methods have been rarely applied to studies in ice wedges. Thus, we attempted to display distribution and shape of ice wedges using a ground penetrating radar (GPR) and a direct current (DC) resistivity meter. The surveys were performed at a comprehensive monitoring site of ice-wedging in Adventdalen, Svalbard, where troughs and small cracks form polygonal patterns on the ground. Unknown structure below such new cracks is also focused in this study. We obtained 37 GPR profiles using 250 MHz signal. 2-D resistivity surveys were also performed along 14 GPR profiles. The electrodes were placed at 1 m intervals and their combination followed the Wenner array. In addition, shallow boreholes were dug across 5 troughs/cracks to estimate the width of ice wedge. The analyzed results show parabolic patterns formed by the multiple radar waveforms and largely increasing gradients of DC resistivity below the troughs and small cracks. The strong reflections of the radar signals and the starting zones of the increasing resistivity lay about 1 m deep, which corresponded to the top of ice wedges (0.7-0.9 m deep) revealed by the drilling. In the GPR profiles, a relatively flat pattern of the reflection was sandwiched by a pair of parabolic patterns below each well-developed trough, whereas a sharp parabolic pattern was detected below each small crack. These results mean that the presence of narrow ice wedges is detectable by the GPR method and the top of a parabolic pattern roughly corresponds to one edge of an ice wedge table. In the DC resistivity profiles, a high resistivity core exists below each trough and crack. The high resistivity probably resulted from ice having lower unfrozen water content than the surrounding silt materials. The heights of the cores indicate that the ice wedges were formed at least between 1 m and 3 m deep. The cores are, however

  20. 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.

  1. 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.

  2. Comparison of dosimetric characteristics of Siemens virtual and physical wedges for ONCOR linear accelerator.

    PubMed

    Attalla, Ehab M; Abo-Elenein, H S; Ammar, H; El-Desoky, Ismail

    2010-07-01

    Dosimetric properties of virtual wedge (VW) and physical wedge (PW) in 6- and 10-MV photon beams from a Siemens ONCOR linear accelerator, including wedge factors, depth doses, dose profiles, peripheral doses, are compared. While there is a great difference in absolute values of wedge factors, VW factors (VWFs) and PW factors (PWFs) have a similar trend as a function of field size. PWFs have stronger depth dependence than VWF due to beam hardening in PW fields. VW dose profiles in the wedge direction, in general, match very well with those of PW, except in the toe area of large wedge angles with large field sizes. Dose profiles in the nonwedge direction show a significant reduction in PW fields due to off-axis beam softening and oblique filtration. PW fields have significantly higher peripheral doses than open and VW fields. VW fields have similar surface doses as the open fields, while PW fields have lower surface doses. Surface doses for both VW and PW increase with field size and slightly with wedge angle. For VW fields with wedge angles 45° and less, the initial gap up to 3 cm is dosimetrically acceptable when compared to dose profiles of PW. VW fields in general use less monitor units than PW fields.

  3. 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.

  4. Ice wedges as climate archives - opportunities and limitations

    NASA Astrophysics Data System (ADS)

    Opel, Thomas; Meyer, Hanno; Dereviagin, Alexander; Wetterich, Sebastian; Schirrmeister, Lutz

    2014-05-01

    Permafrost regions are assumed to play a major role for Global Climate Change as they are susceptible to recent warming in particular with regard to the potential release of stored fossil carbon. Permafrost serves as archive of past environmental and climate conditions (such as sedimentation processes, temperature and precipitation regimes as well as landscape and ecosystem development) over tens of thousands of years that can be traced by the study of the frozen deposits, paleontological content and ground ice. Ground ice comprises all types of ice contained in frozen ground, including pore ice, segregation ice and ice wedges. Here, we focus on ice wedges as the most promising climate archive that can be studied by stable water isotope methods analogously to glacier ice. They may be identified by their vertically oriented foliations. Ice wedges form by the repeated filling of wintertime thermal contraction cracks by snow melt water in spring. As the melt water quickly refreezes at negative ground temperature no isotopic fractionation takes place. Hence, the isotopic composition (δ18O, δD, d excess) of wedge ice is assumed to be representative of annual cold period climate conditions, i.e. winter and spring. Ice wedges are widely distributed in non-glaciated high northern latitudes, are diagnostic of permafrost and, in general, indicative of cold and stable climate conditions. They are found in continuous and discontinuous permafrost zones and may also have formed during and survived interglacials. They may provide unique paleo information that is not captured by other climate archives. Usually, ice wedges are dated by radiocarbon dating of organic material incorporated in the ice, but also 36Cl/Cl ratios have been successfully used to date ice wedges. Nevertheless reliable age determination is challenging when studying ice wedges. Here we tackle the potential of ice wedges from the Siberian and American Arctic to trace past climate changes from stable isotope

  5. 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.

  6. 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.

  7. Wedge immersed thermistor bolometers

    NASA Technical Reports Server (NTRS)

    Dreyfus, M. G. (Inventor)

    1964-01-01

    An immersed thermistor bolometer for the detection of ultraviolet, visible, and infrared radiation is described. Two types of immersed bolometers are discussed. The immersion of thermistor flakes in a lens, or half immersed by optical contact on a lens, is examined. Lens materials are evaluated for optimum immersion including fused aluminum oxide, beryllium oxide, and germanium. The application of the bolometer to instruments in which the entrance pupil of the immersion optics has a high aspect ratio is considered.

  8. 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.

  9. 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.

  10. Assessment of computerized treatment planning system accuracy in calculating wedge factors of physical wedged fields for 6 MV photon beams.

    PubMed

    Muhammad, Wazir; Maqbool, Muhammad; Shahid, Muhammad; Hussain, Amjad; Tahir, Sajjad; Matiullah; Rooh, Gul; Ahmad, Tanveer; Lee, Sang Hoon

    2011-07-01

    Wedge filters are commonly used in external beam radiotherapy to achieve a uniform dose distribution within the target volume. The main objective of this study was to investigate the accuracy of the beam modifier algorithm of Theraplan plus (TPP version 3.8) treatment planning system and to confirm that either the beam hardening, beam softening and attenuation coefficients along with wedge geometry and measured wedge factor at single depth and multiple fields sizes can be the replacement of wedged profile and wedged cross-sectional data or not. In this regard the effect of beam hardening and beam softening was studied with physical wedges for 6 MV photons. The Normalized Wedge Factors (NWFs) were measured experimentally as well as calculated with the Theraplan plus, as a function of depth and field size in a water phantom for 15°, 30°, 45°, and 60° wedge filters. The beam hardening and softening was determined experimentally by deriving the required coefficients for all wedge angles. The TPP version 3.8 requires wedge transmission factor at single depth and multiple field sizes. Without incorporating the hardening and softening coefficients the percent difference between measured and calculated NFWs was as high as 7%. After the introduction of these parameters into the algorithm, the agreement between measured and TPP (V 3.8) calculated NWFs were improved to within 2 percent for various depths. Similar improvement was observed in TPP version 3.8 while calculating NWFs for various field sizes when the required coefficients were adjusted. In conclusion, the dose calculation algorithm of TPP version 3.8 showed good accuracy for a 6 MV photon beam provided beam hardening and softening parameters are taken into account. From the results, it is also concluded that, the beam hardening, beam softening and attenuation coefficients along with wedge geometry and measured wedge factor at single depth and multiple fields sizes can be the replacement of wedged profile and

  11. Wedge locality and asymptotic commutativity

    NASA Astrophysics Data System (ADS)

    Soloviev, M. A.

    2014-05-01

    In this paper, we study twist deformed quantum field theories obtained by combining the Wightman axiomatic approach with the idea of spacetime noncommutativity. We prove that the deformed fields with deformation parameters of opposite sign satisfy the condition of mutual asymptotic commutativity, which was used earlier in nonlocal quantum field theory as a substitute for relative locality. We also present an improved proof of the wedge localization property discovered for the deformed fields by Grosse and Lechner, and we show that the deformation leaves the asymptotic behavior of the vacuum expectation values in spacelike directions substantially unchanged.

  12. 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

  13. Effect of a trade between boattail angle and wedge size on the performance of a nonaxisymmetric wedge nozzle

    NASA Technical Reports Server (NTRS)

    Carson, George T., Jr.; Bare, E. Ann; Burley, James R., II

    1987-01-01

    An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine the effect of a boattail angle and wedge-size trade on the performance of nonaxisymmetric wedge nozzles installed on a generic twin-engine fighter aircraft model. Test data were obtained at static conditions and at Mach numbers from 0.60 to 1.25. Angle of attack was held constant at 0 deg. High-pressure air was used to simulate jet exhaust, and the nozzle pressure ratio was varied from 1.0 (jet off) to slightly over 15.0. For the configurations studied, the results indicate that wedge size can be reduced without affecting aeropropulsive performance.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. The opening of a high care hostel for problem drinkers.

    PubMed

    Bretherton, H

    1992-12-01

    This paper gives a personal and practice based account by one of the Team Leaders of the opening of a high-care hostel for problem drinkers in North London. The hostel, Rugby House, was set up to provide detoxification and assessment facilities for thirteen residents. It was part of the Rugby House Project, an alcohol agency in the voluntary sector. The paper explores the processes involved in setting up a new project; how the new paid employees turn a committee's vision into practice; how a group of individuals become a team; the importance of clarity about boundaries and underlying values and assumptions; the need for openness about negative as well as positive feelings; and the recognition that some of the experiences of staff will resonate with those of the residents for whom giving up drinking is a major life change.

  19. 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.

  20. 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.

  1. Stacking and metamorphism of continuous segments of subducted lithosphere in a high-pressure wedge: The example of Alpine Corsica (France)

    NASA Astrophysics Data System (ADS)

    Vitale Brovarone, Alberto; Beyssac, Olivier; Malavieille, Jacques; Molli, Giancarlo; Beltrando, Marco; Compagnoni, Roberto

    2013-01-01

    Alpine Corsica consists of a stack of variably metamorphosed units of continental and Tethys-derived rocks. It represents an excellent example of high-pressure (HP) orogenic belt, such as the Western Alps, exposed over a small and accessible area. Compared to the Western Alps, the geology of Alpine Corsica is poorly unraveled. During the 1970s-80s, based on either lithostratigraphic or metamorphic field observations, various classifications of the belt have been proposed, but these classifications have been rarely matched together. Furthermore, through time, the internal complexity of large domains has been progressively left aside in the frame of large-scale geodynamic reconstructions. As a consequence, major open questions on the internal structure of the belt have remained unsolved. Apart from a few local studies, Alpine Corsica has not benefited of modern developments in petrology and basin research. This feature results in several uncertainties when combining lithostratigraphic and metamorphic patterns and, consequently, in the definition of an exhaustive architecture of the belt. In this paper we provide a review on the geology of Alpine Corsica, paying particular attention to the available lithostratigraphic and metamorphic classifications of the metamorphic terranes. These data are completed by a new and exhaustive metamorphic dataset obtained by means of thermometry based on Raman Spectroscopy of Carbonaceous Material (RSCM). This technique provides reliable insights on the peak temperature of the metamorphic history for CM-bearing metasediments. A detailed metamorphic characterization of metasediments, which have been previously largely ignored due to retrogression or to the lack of diagnostic mineralogy, is thus obtained and fruitfully coupled with the available lithostratigraphic data. Nine main tectono-metamorphic units are defined, from subgreenschist (ca. 280-300 °C) to the lawsonite-eclogite-facies (ca. 500-550 °C) condition. These units are

  2. High-Quality Broadband BVRI Photometry of Benchmark Open Clusters

    NASA Astrophysics Data System (ADS)

    Joner, Michael D.

    Photometric techniques are often used to observe stars and it can be demonstrated that fundamental stellar properties can be observationally determined using calibrated sets of photometric data. Many of the most powerful techniques utilized to calibrate stellar photometry employ the use of stars in clusters since the individual stars are believed to have many common properties such as age, composition, and approximate distance. Broadband photometric Johnson/Cousins BVRI observations are presented for several nearby open clusters. The new photometry has been tested for consistency relative to archival work and shown to be both accurate and precise. The careful use of a regular routine when making photometric observations, along with the monitoring of instrumental systems and the use of various quality control techniques when making observations or performing data reductions, will enhance an observer's ability to produce high-quality photometric measurements. This work contains a condensed review of the history of photometry, along with a brief description of several popular photometric systems that are often utilized in the field of stellar astrophysics. Publications written by Taylor or produced during the early Taylor and Joner collaboration are deemed especially relevant to the current work. A synopsis of seven archival publications is offered, along with a review of notable reports of VRI photometric observations for the nearby Hyades open star cluster. The body of this present work consists of four publications that appeared between the years 2005 and 2008, along with a soon to be submitted manuscript for a fifth publication. Each of these papers deals specifically with high-quality broadband photometry of open clusters with new data being presented for the Hyades, Coma, NGC 752, Praesepe, and M67. It is concluded that the VRI photometry produced during the Taylor and Joner collaborative investigations forms a high-quality data set that has been: (1) stable for

  3. Two critical tapers in a single wedge

    NASA Astrophysics Data System (ADS)

    Smit, J.; Burg, J.-P.; Brun, J.-P.

    2009-04-01

    Thrust involving a ductile décollement (e.g. salt, over-pressured shales) like Zagros, Jura, Pakistan Salt Ranges, Cascades and Makran have in common a small cross-sectional taper, attributed to large thrust spacing and fast frontward propagation above the ductile décollement. Such a low cross-sectional taper has been analytically explained by approximating the ductile layer as a horizon with negligible shear strength. We tested the development of thrust wedges involving a ductile basal décollement of uniform shear strength by means of laboratory experiments. The model consists of a sand layer with initial wedge geometry and a basal ductile décollement of constant thickness and shear strength made of silicone putty. 30% of bulk shortening is applied to the wedge at constant velocity. Thrusting starts in the middle of the wedge, followed by in-sequence frontward propagation. The back part of the wedge, between backstop and the closest thrust, remains undeformed; it passively advances over the base without internal deformation. It appears that both domains have different critical tapers. The inner domain is in a critical state from the onset of shortening (i.e. the initial wedge is already critical), while the frontal domain steadily acquires a state of critical taper by thrusting. This result is at variance with the classical assumption that shortening of a wedge made of homogeneous layers creates a single critical taper. The experimental thrust wedges do show other features characteristic for weak décollement wedges like narrow cross-sectional taper, large thrust spacing and variety in thrust geometries. Application of the results to natural thrust wedges like the Jura Mountains could shed new light on their development and geometry at depth.

  4. 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.

  5. Experimental investigation of hypersonic flow induced separation over double wedges

    NASA Astrophysics Data System (ADS)

    Hashimoto, Tokitada

    2009-09-01

    Flow separation occurs over the compression corners generated by deflected control surfaces on hypersonic re-entry vehicles and in the inlet of scram jet engines. Configurations like a double wedge and double cone model are useful for studying the separated flow features. Flow fields around concave corners are relatively complicated and produce several classical viscous flow features depending on the combination of the first and second wedge or cone half apex angles. Particularly characteristic phenomena are mainly shock/boundary layer, shock/shock interaction, unsteady shear layers and non-linear shock oscillations. Although most of these basic gas dynamics characteristics are well known, it is not clear what happens at high enthalpy conditions. This paper reports a result of flow fields over a double wedge at a stagnation enthalpy of 4.8 MJ/kg. The experiment was carried out in a free piston shock tunnel at a nominal Mach number of 6.99. Schlieren and double exposure holographic interferometry were applied to visualize the flow field over the double wedge.

  6. Highly reversible open framework nanoscale electrodes for divalent ion batteries.

    PubMed

    Wang, Richard Y; Wessells, Colin D; Huggins, Robert A; Cui, Yi

    2013-01-01

    The reversible insertion of monovalent ions such as lithium into electrode materials has enabled the development of rechargeable batteries with high energy density. Reversible insertion of divalent ions such as magnesium would allow the creation of new battery chemistries that are potentially safer and cheaper than lithium-based batteries. Here we report that nanomaterials in the Prussian Blue family of open framework materials, such as nickel hexacyanoferrate, allow for the reversible insertion of aqueous alkaline earth divalent ions, including Mg(2+), Ca(2+), Sr(2+), and Ba(2+). We show unprecedented long cycle life and high rate performance for divalent ion insertion. Our results represent a step forward and pave the way for future development in divalent batteries.

  7. 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.

  8. 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…

  9. 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)

  10. 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.

  11. 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.

  12. ExpertEyes: open-source, high-definition eyetracking.

    PubMed

    Parada, Francisco J; Wyatte, Dean; Yu, Chen; Akavipat, Ruj; Emerick, Brandi; Busey, Thomas

    2015-03-01

    ExpertEyes is a low-cost, open-source package of hardware and software that is designed to provide portable high-definition eyetracking. The project involves several technological innovations, including portability, high-definition video recording, and multiplatform software support. It was designed for challenging recording environments, and all processing is done offline to allow for optimization of parameter estimation. The pupil and corneal reflection are estimated using a novel forward eye model that simultaneously fits both the pupil and the corneal reflection with full ellipses, addressing a common situation in which the corneal reflection sits at the edge of the pupil and therefore breaks the contour of the ellipse. The accuracy and precision of the system are comparable to or better than what is available in commercial eyetracking systems, with a typical accuracy of less than 0.4° and best accuracy below 0.3°, and with a typical precision (SD method) around 0.3° and best precision below 0.2°. Part of the success of the system comes from a high-resolution eye image. The high image quality results from uncasing common digital camcorders and recording directly to SD cards, which avoids the limitations of the analog NTSC format. The software is freely downloadable, and complete hardware plans are available, along with sources for custom parts.

  13. 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.

  14. Distribution and activity of ice wedges across the forest-tundra transition, western Arctic Canada

    NASA Astrophysics Data System (ADS)

    Kokelj, S. V.; Lantz, T. C.; Wolfe, S. A.; Kanigan, J. C.; Morse, P. D.; Coutts, R.; Molina-Giraldo, N.; Burn, C. R.

    2014-09-01

    Remote sensing, regional ground temperature and ground ice observations, and numerical simulation were used to investigate the size, distribution, and activity of ice wedges in fine-grained mineral and organic soils across the forest-tundra transition in uplands east of the Mackenzie Delta. In the northernmost dwarf-shrub tundra, ice wedge polygons cover up to 40% of the ground surface, with the wedges commonly exceeding 3 m in width. The largest ice wedges are in peatlands where thermal contraction cracking occurs more frequently than in nearby hummocky terrain with fine-grained soils. There are fewer ice wedges, rarely exceeding 2 m in width, in uplands to the south and none have been found in mineral soils of the tall-shrub tundra, although active ice wedges are found there throughout peatlands. In the spruce forest zone, small, relict ice wedges are restricted to peatlands. At tundra sites, winter temperatures at the top of permafrost are lower in organic than mineral soils because of the shallow permafrost table, occurrence of phase change at 0°C, and the relatively high thermal conductivity of icy peat. Due to these factors and the high coefficient of thermal contraction of frozen saturated peat, ice wedge cracking and growth is more common in peatlands than in mineral soil. However, the high latent heat content of saturated organic active layer soils may inhibit freezeback, particularly where thick snow accumulates, making the permafrost and the ice wedges in spruce forest polygonal peatlands susceptible to degradation following alteration of drainage or climate warming.

  15. Deformation of brittle-ductile thrust wedges in experiments and nature

    NASA Astrophysics Data System (ADS)

    Smit, J. H. W.; Brun, J. P.; Sokoutis, D.

    2003-10-01

    Even though the rheology of thrust wedges is mostly frictional, a basal ductile decollement is often involved. By comparison with purely frictional wedges, such brittle-ductile wedges generally display anomalous structures such as backward vergence, widely spaced thrust units, and nonfrontward sequences of thrust development. Laboratory experiments are used here to study the deformation of brittle-ductile thrust wedges. Results are compared with natural systems in the Jura Mountains and the northern Pakistan Salt Range and Potwar Plateau. Two series of three models are used to illustrate the effects of varying the basal wedge angle (β) and shortening rate (V). These two parameters directly control variations in relative strength between brittle and ductile layers (BD coupling). Wedges with strong BD coupling (low β and high V) give almost regular frontward sequences with closely spaced thrust units and, as such, are not significantly different from purely frictional wedges. Weak BD coupling (high β and low V) gives dominantly backward thrusting sequences. Intermediate BD coupling produces frontward-backward oscillating sequences. The spacing of thrust units increases as coupling decreases. Back thrusts develop in parts of a wedge where BD coupling is weak, regardless of the thrust sequence. Wedges with weak BD coupling need large amounts of bulk shortening (more than 30%) to attain a state of equilibrium, at which stable sliding along the base occurs. On this basis, we argue that a state of equilibrium has not yet been attained in at least some parts of the Jura Mountains and eastern Salt Range and Potwar Plateau thrust systems.

  16. Two brittle ductile transitions in subduction wedges, as revealed by topography

    NASA Astrophysics Data System (ADS)

    Thissen, C.; Brandon, M. T.

    2013-12-01

    Subduction wedges contain two brittle ductile transitions. One transition occurs within the wedge interior, and a second transition occurs along the decollement. The decollement typically has faster strain rates, which suggests that the brittle ductile transition along the decollement will be more rearward (deeper) than the transition within the interior. However, the presence of distinct rheologies or other factors such as pore fluid pressure along the decollement may reverse the order of the brittle-ductile transitions. We adopt a solution by Williams et al., (1994) to invert for these brittle ductile transitions using the wedge surface topography. At present, this model does not include an s point or sediment loading atop the wedge. The Hellenic wedge, however, as exposed in Crete presents an ideal setting to test these ideas. We find that the broad high of the Mediterranean ridge represents the coulomb frictional part of the Hellenic wedge. The rollover in topography north of the ridge results from curvature of the down going plate, creating a negative alpha depression in the vicinity of the Strabo, Pliny, and Ionian 'troughs' south of Crete. A steep topographic rise out of these troughs and subsequent flattening reflects the brittle ductile transition at depth in both the decollement and the wedge interior. Crete exposes the high-pressure viscous core of the wedge, and pressure solution textures provide additional evidence for viscous deformation in the rearward part of the wedge. The location of the decollement brittle ductile transition has been previously poorly constrained, and Crete has never experienced a subduction zone earthquake in recorded history. Williams, C. A., et al., (1994). Effect of the brittle ductile transition on the topography of compressive mountain belts on Earth and Venus. Journal of Geophysical Research Solid Earth

  17. Numerical simulation of vortex-wedge interaction

    NASA Astrophysics Data System (ADS)

    Park, Jin-Ho; Lee, Duck-Joo

    1994-06-01

    Interactions between vortical flows and a solid surface cause one of the primary sources of noise and unsteady loading. The mechanism of the interaction is studied numerically for a single Rankine vortex impinging upon a wedge. An Euler-Lagrangian method is employed to calculate the unsteady, viscous, incompressible flows in two dimensions. A random vortex method is used to describe the vorticity dominant field. A fast vortex method is used to reduce the computational time in the calculation of the convection velocity of each vortex particle. A Schwarz-Christoffel transformation is used to map the numerical domain onto the physical domain. Vortex partical plots, velocity vectors, and streamlines are presented at selected times for both inviscid and viscous interactions. It is observed that the incident rankine vortex distorts and is split by the wedge as it nears and passes the wedge, and the vortices generated from the leading edge toward the underside of the wedge form into a single vortex. The vorticity orientation of the shed vortex is opposite to that of the incident vortex. It is found that the convection velocity of the shed vortex is changed wheen it comes off the leading edge of the wedge, and the strength of the shed vortex varies with the time during the vortex-wedge interaction. This strength variation is presumed to influence the shed vortex convection velocity. The overall features for the interaction agree well with the experimental results of Ziada and Rockwell.

  18. 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.

  19. 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.

  20. 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%.

  1. 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

  2. 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.

  3. Open Principle for Large High-Resolution Solar Telescopes

    NASA Astrophysics Data System (ADS)

    Hammerschlag, Robert H.; Bettonvil, Felix C. M.; Jägers, Aswin P. L.; Sliepen, Guus

    2009-04-01

    Vacuum solar telescopes solve the problem of image deterioration inside the telescope due to refractive index fluctuations of the air heated by the solar light. However, such telescopes have a practical diameter limit somewhat over 1 m. The Dutch Open Telescope (DOT) was the pioneering demonstrator of the open-telescope technology without need of vacuum, now pursued in the German GREGOR. Important ingredients for this technology are primary beam completely open to natural wind flow, stiff but still open design by principal stiff overall geometries in combination with carefully designed joints and completely open-foldable dome constructions based on tensioned strong cloth. Further developments to large sizes are made within the framework of the design study for a European Solar Telescope (EST).

  4. 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.

  5. Silurian Extrusion Wedge Tectonics in the Central Scandinavian Caledonides

    NASA Astrophysics Data System (ADS)

    Grimmer, J. C.; Glodny, J.; Drüppel, K.; Greiling, R. O.

    2015-12-01

    The Scandian fold-thrust belt of the central Scandinavian Caledonides host the high-grade metamorphic Seve Nappe Complex bounded on top by a normal sense shear zone and at the base by a reverse sense shear zone. Rb-Sr multimineral geochronology in synkinematic assemblages indicates simultaneous movements at the normal-sense roof shear zone and at the reverse-sense floor shear zone between 434 Ma and 429 Ma. Pressure temperature pseudosection calculations provide evidence for eclogite facies metamorphic conditions and nearly isothermal decompression at ~670 ± 50 °C from 17.5 to 14.5 kbar in garnet-kyanite mica schists during reverse-sense shearing, and from 15 to 11 kbar in garnet mica schists during normal-sense shearing. These and other published data and the presence of decompression-related pegmatites dated at 434 Ma and 429 Ma indicate that the Seve nappes form a 1-2 km thin extrusion wedge that extends along strike for at least 150 km. Devonian ductile extensional to transtensional deformation of the more internal parts of the orogen did not affect the early to mid-Silurian extrusion wedge that was preserved in the more external parts of the orogen due to foreland-directed nappe displacements in the order of >400 km. This wedge marks an early stage of exhumation of (ultra-)high-pressure metamorphic rocks and orogenic wedge formation in this part of the Scandinavian Caledonides predating the ≥10 km thick, post-415 Ma exhumation processes of ultrahigh-pressure rocks in southwestern Norway.

  6. The formation of grounding zone wedges

    NASA Astrophysics Data System (ADS)

    Kowal, Katarzyna; Worster, Grae

    2016-11-01

    Ice sheets are generally lubricated by a layer of sub-glacial sediment, or till, which plays a central role in determining their large-scale dynamics. Sub-glacial till has been found to accumulate into distinctive sedimentary wedges at ice-sheet grounding zones, separating floating ice shelves from grounded ice sheets. These grounding-zone wedges have important implications for stabilizing ice sheets against grounding-zone retreat in response to rising sea levels. We develop a theoretical model of wedge formation in which we treat both ice and till as viscous fluids spreading under gravity into an inviscid ocean and present a fluid-mechanical explanation of the formation of these wedges in terms of the jump in hydrostatic loading and unloading of till across the grounding zone. We also conduct a series of fluid-mechanical experiments in a confined setting in which we find that the underlying layer of less viscous fluid accumulates spontaneously in a similar wedge-shaped region at the experimental grounding line. We also extend our theory to more natural, unconfined settings in two dynamical regimes in which the overlying ice is resisted dominantly either by vertical shear or by extensional stresses and compare our findings with available geophysical data. Currently at Northwestern University.

  7. Early complications after high tibial osteotomy: a comparison of two techniques.

    PubMed

    van den Bekerom, Michel P J; Patt, Thomas W; Kleinhout, Miriam Y; van der Vis, Harm M; Albers, G H Rob

    2008-01-01

    This prospective cohort study compared opening wedge high tibial osteotomy with use of the Puddu plate and the Vitoss synthetic cancellous bone versus closing wedge high tibial osteotomy with use of the AO/ASIF L-plate, focusing on complications (nonunions, infections, loss of correction, reoperations) and patient satisfaction (visual linear analog scale). During a 10-month period, we performed high tibial osteotomy for 40 patients experiencing medial knee osteoarthritis and a varus deformity. The average follow-up was 11 months. The complication rate in patients treated with the opening wedge technique was significantly higher regarding tibial nonunion, loss of correction, and material failure. Patients in the closing wedge group were more satisfied with the postoperative result. This study found that the Puddu plate, despite 6 weeks of non-weight bearing facilitating the osseous consolidation with Vitoss cement, was not able to maintain the correction during the time required for bone healing.

  8. Stability of Supersonic Boundary Layers Over Blunt Wedges

    NASA Technical Reports Server (NTRS)

    Balakumar, Ponnampalam

    2006-01-01

    Receptivity and stability of supersonic boundary layers over blunt flat plates and wedges are numerically investigated at a free stream Mach number of 3.5 and at a high Reynolds number of 10(exp 6)/inch. Both the steady and unsteady solutions are obtained by solving the full Navier-Stokes equations using the 5th-order accurate weighted essentially non-oscillatory (WENO) scheme for space discretization and using third-order total-variation-diminishing (TVD) Runge-Kutta scheme for time integration. Computations are performed for a flat plate with leading edge thicknesses of 0.0001, 0.001, 0.005 and 0.01 inches that give Reynolds numbers based on the leading edge thickness ranging from 1000 to 10000. Calculations are also performed for a wedge of 10 degrees half angle with different leading edge radii 0.001 and 0.01 inches. The linear stability results showed that the bluntness has a strong stabilizing effect on the stability of two-dimensional boundary layers. The transition Reynolds number for a flat plate with a leading edge thickness of 0.01 inches is about 3.5 times larger than it is for the Blasius boundary layer. It was also revealed that boundary layers on blunt wedges are far more stable than on blunt flat plates.

  9. 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.

  10. 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°.

  11. Evaluation method of lead measurement accuracy of gears using a wedge artefact

    NASA Astrophysics Data System (ADS)

    Komori, Masaharu; Takeoka, Fumi; Kubo, Aizoh; Okamoto, Kazuhiko; Osawa, Sonko; Sato, Osamu; Takatsuji, Toshiyuki

    2009-02-01

    The reduction of the vibration and noise of gears is an important issue in mechanical devices such as vehicles and wind turbines. The characteristics of the vibration and noise of gears are markedly affected by deviations of the tooth flank form of micrometre order; therefore, a strict quality control of the tooth flank form is required. The accuracy of the lead measurement for a gear-measuring instrument is usually evaluated using a master gear or a lead master. However, it is difficult to manufacture masters with high accuracy because the helix is a complicated geometrical form. In this paper, we propose a method of evaluating a gear-measuring instrument using a wedge artefact, which includes a highly precise plane surface. The concept of the wedge artefact is described and a mathematical model of the measuring condition of the wedge artefact is constructed. Theoretical measurement results for the wedge artefact are calculated. The wedge artefact is designed and produced on the basis of the theoretical measurement results. A measurement experiment using the wedge artefact is carried out and its effectiveness is verified.

  12. 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.

  13. 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.

  14. 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

  15. Two-dimensional meniscus in a wedge

    SciTech Connect

    Kagan, M.; Pinczewski, W.V.; Oren, P.E.

    1995-03-15

    This paper presents a closed-form analytical solution of the augmented Young-Laplace equation for the meniscus profile in a two-dimensional wedge-shaped capillary. The solution is valid for monotonic forms of disjoining pressure which are repulsive in nature. In the limit of negligible disjoining pressure, it is shown to reduce to the classical solution of constant curvature. The character of the solution is examined and examples of practical interest which demonstrate the application of the solution to the computation of the meniscus profile in a wedge-shaped capillary are discussed.

  16. 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…

  17. 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.

  18. 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…

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

    SciTech Connect

    Lee, Seyong; Kim, Jungwon; 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.

  20. 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…

  1. 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

  2. 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.

  3. COAST: Cascadia Open-Access Seismic Transects

    NASA Astrophysics Data System (ADS)

    Holbrook, W.; Johnson, H. P.; Kent, G.; Keranen, K. M.; Tobin, H. J.; Trehu, A. M.

    2012-12-01

    The Cascadia margin is the site of active subduction, where the Juan de Fuca plate subducts under the North American plate at a rate of ~35 mm/yr. This system is of great scientific and societal interest, as it is capable of very large (Mw~9) earthquakes, creates volcanic hazards in the Cascades, and hosts periodic episodic tremor and slip (ETS) episodes. Despite evidence that the system has generated large megathrust earthquakes, limited seismicity creates large uncertainties in the position, structure, and physical state of the plate boundary. The COAST (Cascadia Open-Access Seismic Transects) project conducted an open-access, open-participation 2D seismic survey of the Cascadia subduction margin off Grays Harbor, WA, that will provide benchmark seismic images to address key scientific issues regarding the location, physical state, fluid budget, and associated methane systems of the subducting plate boundary and overlying crust. We collected seismic reflection, multibeam bathymetric, sidescan sonar, gravity, and magnetic data on the Cascadia subduction margin from the R/V Langseth in July 2012 in a high-priority GeoPRISMS corridor off Grays Harbor, Washington. The cruise was open-participation, with an organized shipboard education and training program, and the data are open-access, with immediate, full release to the community of all geophysical data. Project goals include (1) determining the location of the offshore plate boundary, (2) constraining sediment subduction and plate boundary roughness, (3) estimating pore fluid pathways, (4) determining controls on methane distribution, and (5) imaging compressional and extensional structures that may pose geohazards on the Cascadia margin. Initial observations include the following: (1) The Pleistocene accretionary wedge is well imaged and shows landward-vergent thrust faulting throughout our survey area. An outboard series of ramp-and-thrust structures gives way to a region characterized by folds that separate

  4. The effects of tibia profile, distraction angle, and knee load on wedge instability and hinge fracture: A finite element study.

    PubMed

    Weng, Pei-Wei; Chen, Chia-Hsien; Luo, Chu-An; Sun, Jui-Sheng; Tsuang, Yang-Hwei; Cheng, Cheng-Kung; Lin, Shang-Chih

    2017-04-01

    Several plate systems for high tibial osteotomy (HTO) have been developed to stabilize the opening wedge of an osteotomized tibia. Among them, the TomoFix system, having a quasi-straight and T-shaped design, has been widely adopted in the literature. However, this system is implemented by inserting a lag (i.e., cortical) screw through the proximal combi-hole, to deform the plate and pull the distal tibia toward the plate. This process potentially induces plate springback and creates an elastic preload on the osteotomized tibia, especially at the lateral hinge of the distracted wedge. Using the finite-element method, this study aims to investigate the contoured effect of lag-screw application on the biomechanical behavior of the tibia-plate construct. Two tibial profiles (normal and more concave), three distraction angles (6°, 9°, and 12°), and three knee loads (intraoperative: contouring plate; postoperative: weight and nonweight bearing) are systematically varied in this study. The wedge instability and fracture risk at the lateral hinge are chosen as the comparison indices. The results show the necessity of preoperative planning for a precontoured procedure, rather than elastic deformation using a lag screw. Within the intraoperative period, a more concave tibial profile and/or reduced distraction angle (i.e., 6° or 9°) necessitate a higher compressive load to elastically deform the plate, thereby deteriorating the lateral-hinge fracture risk. A precontoured plate is recommended in the case that the proximal tibia is highly concave and the distraction angle is insufficient to stretch the tibial profile.

  5. Highly dynamically evolved intermediate-age open clusters

    NASA Astrophysics Data System (ADS)

    Piatti, Andrés E.; Dias, Wilton S.; Sampedro, Laura M.

    2017-04-01

    We present a comprehensive UBVRI and Washington CT1T2 photometric analysis of seven catalogued open clusters, namely: Ruprecht 3, 9, 37, 74, 150, ESO 324-15 and 436-2. The multiband photometric data sets in combination with 2MASS photometry and Gaia astrometry for the brighter stars were used to estimate their structural parameters and fundamental astrophysical properties. We found that Ruprecht 3 and ESO 436-2 do not show self-consistent evidence of being physical systems. The remained studied objects are open clusters of intermediate age (9.0 ≤ log(t yr-1) ≤ 9.6), of relatively small size (rcls ∼ 0.4-1.3 pc) and placed between 0.6 and 2.9 kpc from the Sun. We analysed the relationships between core, half-mass, tidal and Jacoby radii as well as half-mass relaxation times to conclude that the studied clusters are in an evolved dynamical stage. The total cluster masses obtained by summing those of the observed cluster stars resulted to be ∼10-15 per cent of the masses of open clusters of similar age located closer than 2 kpc from the Sun. We found that cluster stars occupy volumes as large as those for tidally filled clusters.

  6. Benchmarking numerical models of brittle thrust wedges

    NASA Astrophysics Data System (ADS)

    Buiter, Susanne J. H.; Schreurs, Guido; Albertz, Markus; Gerya, Taras V.; Kaus, Boris; Landry, Walter; le Pourhiet, Laetitia; Mishin, Yury; Egholm, David L.; Cooke, Michele; Maillot, Bertrand; Thieulot, Cedric; Crook, Tony; May, Dave; Souloumiac, Pauline; Beaumont, Christopher

    2016-11-01

    We report quantitative results from three brittle thrust wedge experiments, comparing numerical results directly with each other and with corresponding analogue results. We first test whether the participating codes reproduce predictions from analytical critical taper theory. Eleven codes pass the stable wedge test, showing negligible internal deformation and maintaining the initial surface slope upon horizontal translation over a frictional interface. Eight codes participated in the unstable wedge test that examines the evolution of a wedge by thrust formation from a subcritical state to the critical taper geometry. The critical taper is recovered, but the models show two deformation modes characterised by either mainly forward dipping thrusts or a series of thrust pop-ups. We speculate that the two modes are caused by differences in effective basal boundary friction related to different algorithms for modelling boundary friction. The third experiment examines stacking of forward thrusts that are translated upward along a backward thrust. The results of the seven codes that run this experiment show variability in deformation style, number of thrusts, thrust dip angles and surface slope. Overall, our experiments show that numerical models run with different numerical techniques can successfully simulate laboratory brittle thrust wedge models at the cm-scale. In more detail, however, we find that it is challenging to reproduce sandbox-type setups numerically, because of frictional boundary conditions and velocity discontinuities. We recommend that future numerical-analogue comparisons use simple boundary conditions and that the numerical Earth Science community defines a plasticity test to resolve the variability in model shear zones.

  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. Benchmarking analogue models of brittle thrust wedges

    NASA Astrophysics Data System (ADS)

    Schreurs, Guido; Buiter, Susanne J. H.; Boutelier, Jennifer; Burberry, Caroline; Callot, Jean-Paul; Cavozzi, Cristian; Cerca, Mariano; Chen, Jian-Hong; Cristallini, Ernesto; Cruden, Alexander R.; Cruz, Leonardo; Daniel, Jean-Marc; Da Poian, Gabriela; Garcia, Victor H.; Gomes, Caroline J. S.; Grall, Céline; Guillot, Yannick; Guzmán, Cecilia; Hidayah, Triyani Nur; Hilley, George; Klinkmüller, Matthias; Koyi, Hemin A.; Lu, Chia-Yu; Maillot, Bertrand; Meriaux, Catherine; Nilfouroushan, Faramarz; Pan, Chang-Chih; Pillot, Daniel; Portillo, Rodrigo; Rosenau, Matthias; Schellart, Wouter P.; Schlische, Roy W.; Take, Andy; Vendeville, Bruno; Vergnaud, Marine; Vettori, Matteo; Wang, Shih-Hsien; Withjack, Martha O.; Yagupsky, Daniel; Yamada, Yasuhiro

    2016-11-01

    We performed a quantitative comparison of brittle thrust wedge experiments to evaluate the variability among analogue models and to appraise the reproducibility and limits of model interpretation. Fifteen analogue modeling laboratories participated in this benchmark initiative. Each laboratory received a shipment of the same type of quartz and corundum sand and all laboratories adhered to a stringent model building protocol and used the same type of foil to cover base and sidewalls of the sandbox. Sieve structure, sifting height, filling rate, and details on off-scraping of excess sand followed prescribed procedures. Our analogue benchmark shows that even for simple plane-strain experiments with prescribed stringent model construction techniques, quantitative model results show variability, most notably for surface slope, thrust spacing and number of forward and backthrusts. One of the sources of the variability in model results is related to slight variations in how sand is deposited in the sandbox. Small changes in sifting height, sifting rate, and scraping will result in slightly heterogeneous material bulk densities, which will affect the mechanical properties of the sand, and will result in lateral and vertical differences in peak and boundary friction angles, as well as cohesion values once the model is constructed. Initial variations in basal friction are inferred to play the most important role in causing model variability. Our comparison shows that the human factor plays a decisive role, and even when one modeler repeats the same experiment, quantitative model results still show variability. Our observations highlight the limits of up-scaling quantitative analogue model results to nature or for making comparisons with numerical models. The frictional behavior of sand is highly sensitive to small variations in material state or experimental set-up, and hence, it will remain difficult to scale quantitative results such as number of thrusts, thrust spacing

  9. High Power/High Voltage Rechargeable Batteries Open New Opportunities for Space Missions

    NASA Astrophysics Data System (ADS)

    Borthomieu, Y.; Brochard, P.; Lagattu, B.; Netchev, K.

    2008-09-01

    Scientific missions probes, new generation of launchers and satellites are increasingly requesting high power (permanent or pulses). The introduction of a range of rechargeable cells capable of delivering up and receiving high current addresses these needs and opens new horizons for future space missions power supply.Moreover, high power is often linked to high voltage and such need becomes more and more common for space & defence applications. The aim of the high voltage is to carry reasonable current in the harness of the electrical systems.This paper presents Saft answers to these demands, for existing launchers and also for in development ones, as well as for other markets with similar needs, such as military equipment or underwater vehicles.

  10. 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...

  11. 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...

  12. 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...

  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, 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...

  15. 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...

  16. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

    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

  18. 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

  19. 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.

  20. Crossing the boundary: experimental investigation of water entry conditions of V-shaped wedges

    NASA Astrophysics Data System (ADS)

    Xiao, Tingben; Yohann, Daniel; Vincent, Lionel; Jung, Sunghwan; Kanso, Eva

    2016-11-01

    Seabirds that plunge-dive at high speeds exhibit remarkable abilities to withstand and mitigate impact forces. To minimize these forces, diving birds streamline their shape at impact, entering water with their sharp beak first. Here, we investigate the impact forces on rigid V-shaped wedges crossing the air-water interface at high Weber numbers. We vary the impact velocity V by adjusting the height from which the wedge is dropped. Both a high-speed camera and a force transducer are used to characterize the impact. We found that the splash base and air cavity show little dependence on the impact velocity when rescaling by inertial time d / V , where d is the breadth of the wedge. The peak impact force occurs at time tp smaller than the submersion time ts such that the ratio tp /ts is almost constant for all wedges and impact velocities V. We also found that the maximum impact force, like drag force, scales as AV2 , where A is the cross-sectional area of the wedge. We then propose analytical models of the impact force and splash dynamics. The theoretical predictions agree well with our experimental results. We conclude by commenting on the relevance of these results to understanding the mechanics of diving seabirds. We acknowledge support from the National Science Foundation.

  1. Computer dosimetry for flattened and wedged fast-neutron beams.

    PubMed

    Hogstrom, K R; Smith, A R; Almond, P R; Otte, V A; Smathers, J B

    1976-01-01

    Beam flattening by the use of polyethylene filters has been developed for the 50-MeV d in equilibrium Be fast-neutron therapy beam at the Texas A&M Variable-Energy Cyclotron (TAMVEC) as a result of the need for a more uniform dose distribution at depth within the patient. A computer algorithm has been developed that allows the use of a modified decrement line method to calculate dose distributions; standards decrement line methods do not apply because of off-axis peaking. The dose distributions for measured flattened beams are transformed into distributions that are physically equivalent to an unflattened distribution. In the transformed space, standard decrement line theory yields a distribution for any field size which, by applying the inverse transformation, generates the flattened dose distribution, including the off-axis peaking. A semiempirical model has been constructed that allows the calculation of dose distributions for wedged beams from open-beam data.

  2. Electromagnetic scattering by pyramidal and wedge absorber

    NASA Technical Reports Server (NTRS)

    Dewitt, Brian T.; Burnside, Walter D.

    1988-01-01

    Electromagnetic scattering from pyramidal and wedge absorbers used to line the walls of modern anechoic chambers is measured and compared with theoretically predicted values. The theoretical performance for various angles of incidence is studied. It is shown that a pyramidal absorber scatters electromagnetic energy more as a random rough surface does. The apparent reflection coefficient from an absorber wall illuminated by a plane wave can be much less than the normal absorber specifications quoted by the manufacturer. For angles near grazing incidence, pyramidal absorbers give a large backscattered field from the pyramid side-faces or edges. The wedge absorber was found to give small backscattered fields for near-grazing incidence. Based on this study, some new guidelines for the design of anechoic chambers are advocated because the specular scattering models used at present do not appear valid for pyramids that are large compared to the wavelength.

  3. The effect of décollement dip on geometry and kinematics of model accretionary wedges

    NASA Astrophysics Data System (ADS)

    Koyi, Hemin A.; Vendeville, Bruno C.

    2003-09-01

    We conducted a series of sand-box models shortened asymmetrically above a frictional-plastic décollement to study the influence of amount and sense of the décollement dip on the geometry and kinematics of accretionary wedges. Model results illustrate that the amount and direction of décollement dip strongly influence the geometry and mode of deformation of the resulting wedge. In general, for models having similar décollement frictional parameters, the resulting wedge is steeper, grows higher and is shorter when shortened above a décollement that dips toward the hinterland. At 42% bulk shortening, the length/height ratio of wedges formed above a 5°-dipping décollement was equal to 2.4 whereas this ratio was equal to 3 for wedges shortened above a horizontal décollement. Moreover, models with a hinterland dipping décollement undergo larger amounts of layer parallel compaction (LPC) and area loss than models shortened above a non-dipping décollement. The effect of décollement dip on wedge deformation is most pronounced when basal friction is relatively high (μ b=0.55), whereas its effect is less significant in models where the basal décollement has a lower friction (μ b=0.37). Model results also show that increasing basal slope has a similar effect to that of increasing basal friction; the wedge grows taller and its critical taper steepens.

  4. High-frequency EPR applications of open nonradiative resonators.

    PubMed

    Annino, G; Fittipaldi, M; Martinelli, M; Moons, H; Van Doorslaer, S; Goovaerts, E

    2009-09-01

    A new class of open single-mode cavities, the nonradiative (NR) resonators, has recently been proposed in order to overcome the limitations of standard cylindrical cavities and Fabry-Perot resonators at millimeter wavelengths. This paper presents the first applications of a NR resonator in W-band pulsed electron paramagnetic resonance spectroscopy. It consists of a cylindrical cavity having a lateral aperture that represents about 35% of its total height. Electron-spin-echo measurements performed on different samples show that the signal-to-noise ratio and the optimal pulse length obtained with the proposed device are comparable to those obtained with the closed cavity used in the commercial W-band spectrometer, at both cryogenic and room temperature. Similar results have been obtained for paramagnetic species optically activated by means of an optical fiber inserted in the aperture of the resonator. The insertion losses estimated for the probe employed with the NR resonator are higher than those of the commercial probe, hence, demonstrating that the proposed cavity holds the promise of improved resonator performance.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens

    PubMed Central

    Hansen, S. M.; Schmandt, B.; Levander, A.; Kiser, E.; Vidale, J. E.; Abers, G. A.; Creager, K. C.

    2016-01-01

    Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, resulting in a cold mantle wedge that is unlikely to generate melt. Consequently, the forearc location of Mount St Helens raises questions regarding the extent of the cold mantle wedge and the source region of melts that are responsible for volcanism. Here using, high-resolution active-source seismic data, we show that Mount St Helens sits atop a sharp lateral boundary in Moho reflectivity. Weak-to-absent PmP reflections to the west are attributed to serpentinite in the mantle-wedge, which requires a cold hydrated mantle wedge beneath Mount St Helens (<∼700 °C). These results suggest that the melt source region lies east towards Mount Adams. PMID:27802263

  11. Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens.

    PubMed

    Hansen, S M; Schmandt, B; Levander, A; Kiser, E; Vidale, J E; Abers, G A; Creager, K C

    2016-11-01

    Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, resulting in a cold mantle wedge that is unlikely to generate melt. Consequently, the forearc location of Mount St Helens raises questions regarding the extent of the cold mantle wedge and the source region of melts that are responsible for volcanism. Here using, high-resolution active-source seismic data, we show that Mount St Helens sits atop a sharp lateral boundary in Moho reflectivity. Weak-to-absent PmP reflections to the west are attributed to serpentinite in the mantle-wedge, which requires a cold hydrated mantle wedge beneath Mount St Helens (<∼700 °C). These results suggest that the melt source region lies east towards Mount Adams.

  12. Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens

    NASA Astrophysics Data System (ADS)

    Hansen, S. M.; Schmandt, B.; Levander, A.; Kiser, E.; Vidale, J. E.; Abers, G. A.; Creager, K. C.

    2016-11-01

    Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, resulting in a cold mantle wedge that is unlikely to generate melt. Consequently, the forearc location of Mount St Helens raises questions regarding the extent of the cold mantle wedge and the source region of melts that are responsible for volcanism. Here using, high-resolution active-source seismic data, we show that Mount St Helens sits atop a sharp lateral boundary in Moho reflectivity. Weak-to-absent PmP reflections to the west are attributed to serpentinite in the mantle-wedge, which requires a cold hydrated mantle wedge beneath Mount St Helens (<~700 °C). These results suggest that the melt source region lies east towards Mount Adams.

  13. 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.

  14. 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.

  15. Shock Wave Boundary Layer Interaction Mechanism on a Double Wedge Geometry

    NASA Astrophysics Data System (ADS)

    Celik, Bayram; Barada, Mohammad Adel El Hajj Ali; Durna, Ahmet Selim

    2015-11-01

    A hypersonic test series by Swantek & Austin report complex shock wave boundary layer interaction mechanisms and unsteady surface heat flux from a double wedge geometry in a low enthalpy Mach 7 flow. In order to understand the physics of the flow and the heat transfer, we study the flow computationally and compare the results for the double wedge geometries, whose second angle is higher and lower than the maximum deflection angle at Mach 7. Apart from the numbers of comprehensive computational studies on the subject available in open literature, our study aims to describe the flow physics by taking the influence of both boundary layers that are formed on the two walls of the wedge into account. In addition to describing the flow and heat transfer mechanisms, we investigate the time for the flows to reach steady state. We evaluate the interaction mechanisms in term of instant and time average surface heat flux distributions. We perform all computations using a finite volume based compressible Navier-Stokes solver, rhoCentralFoam, which is one of the several compressible flow solvers of an open source software, openFOAM.

  16. 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.

  17. Plastic deformation of a wedge by a sliding punch

    NASA Astrophysics Data System (ADS)

    Nepershin, R. I.

    2016-11-01

    We present a self-similar solution of the problem of deformation of an ideally plastic wedge by a sliding punch with regard to contact friction; such a solution generalizes the well-known solutions of the problem of wedge penetration into a plastic half-space and of compression of an ideally plastic wedge by a plane punch. The problem is of interest for modeling the processes of plastic deformation of rough surfaces of metal pieces by a rigid tool.

  18. 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.

  19. Principle and analysis of the moving-optical-wedge interferometer.

    PubMed

    Yang, Qinghua; Zhou, Renkui; Zhao, Baochang

    2008-05-01

    A new type of interferometer, the moving-optical-wedge interferometer, is presented, and its principle and properties are studied. The novel interferometer consists of one beam splitter, two flat fixed mirrors, two fixed compensating plates, one fixed optical wedge, and one moving optical wedge. The optical path difference (OPD) as a function of the displacement of the moving optical wedge from the zero path difference position is accomplished by the straight reciprocating motion of the moving optical wedge. A large physical shift of the moving optical wedge corresponds to a very short OPD value of the new interferometer if the values of the wedge angle and the refractive index of the two optical wedges are given properly. The new interferometer is not so sensitive to the velocity variation of the moving optical wedge and the mechanical disturbances compared with the Michelson interferometer, and it is very applicable to low-spectral-resolution application for any wavenumber region from the far infrared down to the ultraviolet.

  20. Spot size effects in miniaturized moving-optical-wedge interferometer.

    PubMed

    Al-Saeed, Tarek A; Khalil, Diaa A

    2011-06-10

    In this paper we study the effect of diffraction on the performance of a miniaturized moving-optical-wedge interferometer. By using the Gaussian model, we calculate the degradation of the interferometer visibility due to diffraction effects. We use this model to optimize the detector size required to obtain maximum visibility and study its effect on resolution of Fourier transform spectrometers based on a moving-optical-wedge interferometer. A comparison between these effects in Michelson and wedge interferometers is also presented showing the advantage of the moving-optical-wedge interferometer in suppressing the diffraction effects with respect to the Michelson interferometer.

  1. 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.

  2. Oxidation sharpening, template stripping, and passivation of ultra-sharp metallic pyramids and wedges.

    PubMed

    Im, Hyungsoon; Oh, Sang-Hyun

    2014-02-26

    Ultra-sharp metallic pyramids and wedges with tunable tip angles and 5-nm tip radii are replicated from oxidation-sharpened silicon templates with high throughput (80 million pyramids per wafer). Atomic layer deposition of Al2 O3 shells can protect these sharp pyramidal tips for subsequent usage in near-field imaging.

  3. Kees Zwaan, open principle, future of high-resolution solar telescopes

    NASA Astrophysics Data System (ADS)

    Hammerschlag, R. H.; Bettonvil, F. C. M.

    2013-01-01

    It was around the 1970s that during site-test campaigns masts were erected up till 30 m height with sensors at several heights for the measurement of temperature fluctuations. Kees Zwaan discovered that the fluctuations decrease drastically at heights from about 15 m and upward when there is some wind. The conclusion from this experience was the open telescope principle: a telescope completely free in the air 15 m or more above the ground. The Dutch Open Telescope (DOT) was the pioneering demonstrator of the open-telescope technology. Now that larger high-resolution telescopes come in view, it is time to analyze again the principle: the essentials for proper working of the open principle and the design consequences for the new generation of high-resolution solar telescopes.

  4. Cornelis Zwaan, open principle, and the future of high-resolution solar telescopes

    NASA Astrophysics Data System (ADS)

    Hammerschlag, Robert H.; Bettonvil, Felix C. M.; Jägers, Aswin P. L.; Sliepen, Guus

    2008-07-01

    It was in the years around 1970 that during site-test campaigns for JOSO masts were erected up till 30 m height with sensors at several heights for the measurement of temperature fluctuations. Cornelis (Kees) Zwaan discovered that the fluctuations decrease drastically at heights from about 15 m and upward when there is some wind. The conclusion from this experience was the open telescope principle: the telescope should be completely free in the air 15 m or more above the ground. The Dutch Open Telescope (DOT) was the pioneering demonstrator of the open-telescope technology. Now that larger high-resolution telescopes come in view, it is time to analyze again the principle: (i) the essentials for proper working of the open principle; (ii) the differences with nighttime observations particularly concerning the seeing; (iii) the design consequences for the new generation of high-resolution solar telescopes.

  5. Colluvial wedge imaging using traveltime and waveform tomography along the Wasatch Fault near Mapleton, Utah

    NASA Astrophysics Data System (ADS)

    Buddensiek, M.-L.; Sheng, J.; Crosby, T.; Schuster, G. T.; Bruhn, R. L.; He, R.

    2008-02-01

    Four high-resolution seismic surveys were conducted across the Wasatch Fault Zone near Mapleton, Utah. The objective was twofold: (1) To use velocity tomograms and reflection images to delineate fault structures and colluvial wedges to more than twice the depth of the Mapleton Megatrench excavated by URS personnel, (2) to assess the strengths and limitations of traveltime and waveform tomography by synthetic studies and comparison of the tomogram to the ground truth seen in the Megatrench log. Four out of the five faults within the trench area are accurately identified in the migrated image and in the tomograms, and the main fault's dip angle is estimated to be between 71 and 80°. Two additional faults are interpreted outside the trench. The faults can be delineated down to 30 m below the surface, which is 20 m deeper than the excavated trench. Five out of six colluvial wedges found in the trench log were seen as low-velocity zones (LVZs) in the tomogram, however the biggest colluvial wedge could not be identified by either tomography method. Waveform tomography prevailed over ray-based traveltime tomography by more clearly recovering the faults and LVZs. A newly discovered LVZ at a depth of 18-21 m below the surface possibly represents a colluvial wedge and is estimated to be less than 21000 years old. If this LVZ is a colluvial wedge, the earthquake history obtained by trenching can be extended from 13500 to 21000 yr with seismic tomography. Our results further demonstrate the capability of tomography in identifying faults, and show that waveform tomography more accurately resolves colluvial wedges compared to traveltime tomography. However, despite the successful recovery of most faults and some, but not all, colluvial wedges, both tomography methods show many more LVZs besides the wedges, so that an unambiguous interpretation cannot be made. A major part of the ambiguity in the tomograms is due to the many major faults, which result in an uneven raypath

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

    NASA Astrophysics Data System (ADS)

    Sadeh, Irit; Zion, Michal

    2012-10-01

    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 differences between the two groups: Open inquiry students were more satisfied and felt they gained benefits from implementing the project to a greater extent than guided inquiry students. On the other hand, regarding documentation throughout the project, guided inquiry students believed that they conducted more documentation, as compared to their open inquiry peers. No significant differences were found regarding `the investment of time', but significant differences were found in the time invested and difficulties which arose concerning the different stages of the inquiry process: Open inquiry students believed they spent more time in the first stages of the project, while guided inquiry students believed they spent more time in writing the final paper. In addition, other differences were found: Open inquiry students felt more involved in their project, and felt a greater sense of cooperation with others, in comparison to guided inquiry students. These findings may help teachers who hesitate to teach open inquiry to implement this method of inquiry; or at least provide their students with the opportunity to be more involved in inquiry projects, and ultimately provide their students with more autonomy, high-order thinking, and a deeper understanding in performing science.

  7. 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...

  8. 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

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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…

  14. 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?…

  15. Compact optical isolator for fibers using birefringent wedges.

    PubMed

    Shirasaki, M; Asama, K

    1982-12-01

    A new type of optical isolator for fibers is proposed in this paper. A birefringent wedge used to separate and combine the polarized light is developed, giving the isolator low forward loss and high isolation. The antire-flection process at the fiber endface reduces the forward loss and reflected return. A forward loss of 0.8 dB, a backward loss of 35 dB, and a reflected return of -32 dB were obtained. These characteristics were measured from fiber to fiber using multimode fibers with 50-/microm core diam at a wavelength of 1.3 microm. Details of the design, fabrication, and characteristics of this isolator are presented.

  16. 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.

  17. Substorm Current Wedge at Earth and Mercury

    NASA Astrophysics Data System (ADS)

    Kepko, L.; Glassmeier, K.-H.; Slavin, J. A.; Sundberg, T.

    2015-01-01

    This chapter reviews magnetospheric substorms and dipolarizations observed at both Earth and Mercury. It briefly discusses new insights into the physics of the substorm current wedge (SCW) that have been revealed the past few years. The formation and evolution of the SCW are closely tied to the braking of flows convecting flux away from the reconnection site and the resultant near-planet flux pileup that creates the dipolarization. At Earth, the SCW plays a critical role in substorms, coupling magnetospheric to ionospheric motions, deflecting incoming plasma flows, and regulating the dissipation of pressure built up in the near-Earth magnetosphere during dipolarization. The lack of a conducting boundary at Mercury provides a natural experiment to examine the role of an ionosphere on regulating magnetospheric convection. Energetic particles may play a much greater role within substorms at Mercury than at Earth, providing another opportunity for comparative studies.

  18. 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

  19. 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.

  20. Fabrication of wedged multilayer Laue lenses

    DOE PAGES

    Prasciolu, M.; Leontowich, A. F. G.; Krzywinski, J.; ...

    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

  1. Unscented Kalman filter with open-loop compensation for high dynamic GNSS carrier tracking

    NASA Astrophysics Data System (ADS)

    Wang, Wen-Jing; Chen, Xi; Han, Shuai; Meng, Wei-Xiao; Zhang, Yi

    2009-12-01

    Because of the limit of the loop-band, traditional carrier tracking loop of GNSS receiver can't work in high dynamic conditions with large Doppler frequency, for which an open-loop carrier tracking method based on UKF is proposed. Upon this new tracking loop, the four-dimensionality UKF phase estimator and a compensator is designed to modify the estimative values. By simulating the high dynamic trace of the plat of GNSS receiver, this new method is compared to the closed loop mainly in the aspects of tracking errors, compensation effects and unlocking probability. Simulations show that (1) the proposed open-loop compensation method can give attention to the precision and the dynamics better, with high stability, (2) compared with the closed loop, the open-loop carrier tracking method can improve the tracking precision, with 50% decrease of the tracking errors; and (3) the convergence of this new method is much better, leading to lower unlocking probability.

  2. High voltage, high power operation of the plasma erosion opening switch

    SciTech Connect

    Neri, J.M.; Boller, J.R.; Ottinger, P.F.; Weber, B.V.; Young, F.C.

    1987-04-07

    A Plasma Erosion Opening Switch (PEOS) is used as the opening switch for a vacuum inductive storage system driven by a 1.8-MV, 1.6-TW pulsed power generator. A 135-nH vacuum inductor is current charged to approx.750 kA in 50 ns through the closed PEOS which then opens in <10 ns into an inverse ion diode load. Electrical diagnostics and nuclear activations from ions accelerated in the diode yield a peak load voltage (4.25 MV) and peak load power (2.8 TW) that are 2.4 and 1.8 times greater than ideal matched load values for the same generator pulse.

  3. First 13 years of high-{Tc}: Brief review and open questions

    SciTech Connect

    Pavuna, D.

    1999-12-20

    Exactly 13 years ago, in April 1986, appeared the famous paper by Bednorz and Mueller, that announced a striking discovery of high-{Tc} superconductivity in cuprates. Some 40,000 papers later, scientists are still struggling to understand the high-{Tc} superconductivity. Here the author summarizes 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.

  4. On the Effect of Structural Response on the Hydrodynamic Loading of a Free-Falling Wedge

    NASA Astrophysics Data System (ADS)

    Ikeda, Christine; Taravella, Brandon; Judge, Carolyn

    2016-11-01

    High-speed planing craft are subjected to repeated slamming events in waves that can be very extreme depending on the wave topography, impact angle of the ship, forward speed of the ship, encounter angle, and height out of the water. The current work examines this fluid-structure interaction problem through the use of wedge drop experiments and a theoretical prediction. The experimental program consisted of two 20° deadrise angle wedges dropped from a range of heights, 0 . 15 <= H <= 0 . 6 m, while pressures and accelerations of the slam were measured. The first wedge had a rigid bottom, and the second wedge had a flexible bottom. Both experiments are compared with a non-linear boundary value flat cylinder theory in order to determine the effects of flexibility on the hydrodynamic pressure. The code assumes a rigid structure, therefore, the results between the code and the first experiment are in good agreement. The second experiment shows pressure magnitudes that are lower than the predictions due to the energy required to deform the structure. This work is funded by the Office of Naval Research and the state of Louisiana Board of Regents Industrial Ties and Reseach Subprogram.

  5. 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.

  6. 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.

  7. 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.

  8. ON THE ORIGIN OF HIGH-ALTITUDE OPEN CLUSTERS IN THE MILKY WAY

    SciTech Connect

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

    2016-01-20

    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.

  9. Wedge Dynamics, Forearc Basins, and Seismogenic Zone of Cascadia Megathrust

    NASA Astrophysics Data System (ADS)

    Wang, K.; Hu, Y.

    2005-12-01

    A dynamic critical wedge theory has been developed to describe stress changes in submarine wedges in great earthquake cycles. For most subduction zones, the theory postulates that the actively deforming outer wedge overlies the updip velocity-strengthening part of the subduction fault, and the less deformed inner wedge overlies the megathrust seismogenic zone. Coseismic shear-stress increase in the velocity-strengthening zone drives the outer wedge into the critical state, causing episodic fold-and-thrust deformation, but the inner wedge stays in the stable regime throughout earthquake cycles, maintaining a stable environment for the development of forearc sedimentary basins. This is consistent with the globally observed correlation of the location of forearc basins with rupture zones of subduction earthquakes [Wells et al., JGR, 2003]. However, northern/central Cascadia is complicated by recent, exceedingly rapid growth of the accretionary prism. Until mid-Pleistocene, the megathrust seismogenic zone was probably mostly beneath the forearc basins, in agreement with the modern global observations. Rapid wedge growth and consequent megathrust warming over the past Ma have caused the seismogenic zone to move seaward by tens of km, to a position consistent with inferences based on contemporary geodetic observations. With much of the seismogenic zone located seaward of the forearc basins and beneath the upper continental slope, the dynamic taper theory predicts that coseismic deformation should cause extensional structures on the upper slope but accretion and thrusting on the lower slope, consistent with structural observations [McNeill et al., JGR, 1998].

  10. The Fate of an Innovation: Open Education in Victorian High Schools.

    ERIC Educational Resources Information Center

    King, Ronald Charles

    This study compares open education groups and traditional education groups with respect to student attitudes toward high school; creative thinking of students; collaborative behavior among students; and student preferences for intellectual activities, activities involving change or sameness, and activities involving autonomy or dependence. Groups…

  11. 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…

  12. Zinc-Catalyzed Highly Isoselective Ring Opening Polymerization of rac-Lactide

    PubMed Central

    2015-01-01

    A family of chiral zinc amido-oxazolinate complexes are shown to be highly active and isoselective initiators for the ring-opening polymerization (ROP) of rac-lactide, yielding isotactic stereoblock polylactides (PLA) with Pm up to 0.91. This represents the highest isoselectivity observed with zinc-based catalysts for ROP of rac-lactide. PMID:25068079

  13. "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…

  14. Building Open Educational Resources from the Ground up: South Africa's Free High School Science Texts

    ERIC Educational Resources Information Center

    Petrides, Lisa; Jimes, Cynthia

    2008-01-01

    The relatively new field of open educational resources (OER) is just now receiving more widespread attention and study. As such, there have been few opportunities thus far to share knowledge across program, organizational and national boundaries. This article presents a case study of the development of the South African project Free High School…

  15. Stable and Critical Noncohesive Coulomb Wedges: Exact Elastic Solutions

    NASA Astrophysics Data System (ADS)

    Wang, K.; Hu, Y.

    2004-12-01

    The theory of critically tapered Coulomb wedge has been successfully applied to model active fold-and-thrust belts or submarine accretionary prisms. Brittle mountain building is episodic in nature, controlled by changes in basal friction, erosion and sedimentation, and hydrogeology. Sediment accretion may be modulated by great subduction earthquakes. Between deformation episodes and/or during transition between compressional and extensional tectonics, the Coulomb wedges are stable (i.e., supercritical), to which the critical taper theory does not apply. In this work, we provide an exact elastic solution for stable wedges based on Airy stress functions. The stress equilibrium equation and definition of basal friction and basal and internal pore fluid pressure ratios are exactly the same as those used for Dahlen's [1984] exact solution for critical noncohesive Coulomb wedges, but internal friction μ becomes irrelevant. Given elastic - perfectly Coulomb-plastic rheology, for stresses in a wedge on the verge of Coulomb failure there must co-exist a critical taper solution involving μ and a unique equivalent elastic solution not involving μ . Our elastic solution precisely reduces to Dahlen's critical taper solution for critical conditions. For stable conditions, normal stress perpendicular to the surface slope σ z and shear stress τ xz are identical with those in a critical taper, but the slope-parallel normal stress is different. The elastic solution is also generally applicable to purely elastic wedges and useful for modeling geodetic observations. A stable noncohesive Coulomb wedge differs from a general elastic wedge in that its upper and lower surfaces stay at zero curvature during loading. Dahlen, F.A. (1984), Noncohesive critical Coulomb wedges: An exact solution, JGR, 89, 10,125-10,133.

  16. Saltwater wedge variation in a non-anthropogenic coastal karst aquifer influenced by a strong tidal range (Burren, Ireland)

    NASA Astrophysics Data System (ADS)

    Perriquet, Marie; Leonardi, Véronique; Henry, Tiernan; Jourde, Hervé

    2014-11-01

    Spatial and temporal changes in saltwater wedges in coastal karst aquifers are still poorly understood, largely due to complex mixing processes in these heterogeneous environments, but also due to anthropogenic forcing such as pumping, which commonly affect natural variations in wedges. The purpose of this study was first to characterize the hydrodynamic functioning of a karst aquifer in an oceanic temperate climate with little anthropogenic pressure but strongly influenced by a high tidal range and second, to evaluate the extent and movements of a saltwater wedge influenced by both the tide and the natural recharge of the aquifer. Variations in specific conductivity combined with water chemistry results from six boreholes and two lakes located in the Bell Harbour catchment (western Ireland) enabled us to assess the extent of the intrusion of the saltwater wedge into the aquifer as a function of both karst recharge and tidal movements at high/low and neap/spring tidal cycles. The marked spatial disparity of the saltwater wedge was analysed as a function of both the hydrodynamic and the structural properties of the karst aquifer. Results showed that the extent of the saltwater wedge depended not only on the intrinsic properties of the aquifer but also on the relative influence of the recharge and the tide on groundwater levels, which have opposite effects. Recharge in the Burren area throughout the year is large enough to prevent saltwater intruding more than about one kilometre from the shore. A strong tidal amplitude seems to be the motor of sudden saltwater intrusion observed in the aquifer near the shore while the position of the groundwater level seems to influence the intensity of the salinity increase. Competition between recharge and the tide thus controls the seawater inputs, hence explaining temporal and spatial changes in the saltwater wedge in this coastal karst aquifer.

  17. 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.

  18. 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.

  19. 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.

  20. Refined numerical solution of the transonic flow past a wedge

    NASA Technical Reports Server (NTRS)

    Liang, S.-M.; Fung, K.-Y.

    1985-01-01

    A numerical procedure combining the ideas of solving a modified difference equation and of adaptive mesh refinement is introduced. The numerical solution on a fixed grid is improved by using better approximations of the truncation error computed from local subdomain grid refinements. This technique is used to obtain refined solutions of steady, inviscid, transonic flow past a wedge. The effects of truncation error on the pressure distribution, wave drag, sonic line, and shock position are investigated. By comparing the pressure drag on the wedge and wave drag due to the shocks, a supersonic-to-supersonic shock originating from the wedge shoulder is confirmed.

  1. 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

    2016-05-02

    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.

  2. Fracture and contact problems for an elastic wedge

    NASA Technical Reports Server (NTRS)

    Erdogan, F.; Arin, K.

    1976-01-01

    The paper deals with the plane elastostatic contact problem for an infinite elastic wedge of arbitrary angle. The medium is loaded through a frictionless rigid wedge of a given symmetric profile. Using the Mellin transform formulation the mixed boundary value problem is reduced to a singular integral equation with the contact stress as the unknown function. With the application of the results to the fracture of the medium in mind, the main emphasis in the study has been on the investigation of the singular nature of the stress state around the apex of the wedge and on the determination of the contact pressure.

  3. Fracture and contact problems for an elastic wedge

    NASA Technical Reports Server (NTRS)

    Erdogan, F.; Arin, K.

    1974-01-01

    The plane elastostatic contact problem for an infinite elastic wedge of arbitrary angle is discussed. The medium is loaded through a frictionless rigid wedge of a given symmetric profile. Using the Mellin transform formulation the mixed boundary value problem is reduced to a singular integral equation with the contact stress as the unknown function. With the application of the results to the fracture of the medium in mind, the main emphasis in the study has been on the investigation of the singular nature of the stress state around the apex of the wedge and on the determination of the contact pressure.

  4. Open Science CBS Neuroimaging Repository: Sharing ultra-high-field MR images of the brain.

    PubMed

    Tardif, Christine Lucas; Schäfer, Andreas; Trampel, Robert; Villringer, Arno; Turner, Robert; Bazin, Pierre-Louis

    2016-01-01

    Magnetic resonance imaging at ultra high field opens the door to quantitative brain imaging at sub-millimeter isotropic resolutions. However, novel image processing tools to analyze these new rich datasets are lacking. In this article, we introduce the Open Science CBS Neuroimaging Repository: a unique repository of high-resolution and quantitative images acquired at 7 T. The motivation for this project is to increase interest for high-resolution and quantitative imaging and stimulate the development of image processing tools developed specifically for high-field data. Our growing repository currently includes datasets from MP2RAGE and multi-echo FLASH sequences from 28 and 20 healthy subjects respectively. These datasets represent the current state-of-the-art in in-vivo relaxometry at 7 T, and are now fully available to the entire neuroimaging community.

  5. 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

  6. 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

  7. Open-foldable domes with high-tension textile membranes: The GREGOR dome

    NASA Astrophysics Data System (ADS)

    Hammerschlag, R. H.; Kommers, J. N.; Visser, S.; Bettonvil, F. C. M.; van Schie, A. G. M.; van Leverink, S. J.; Sliepen, G.; Jägers, A. P. L.; Schmidt, W.; Volkmer, R.

    2012-11-01

    Double layers of high-tensioned textile membranes were applied to the completely open-foldable dome for the GREGOR telescope for the first time. Simultaneous climate measurements inside and outside the dome have proven the thermal-insulating capability of this double-layer construction. The GREGOR dome is the result of the continuation of the ESO research on open-foldable domes with textile structures, followed by the research for the DOT dome with high-tensioned textile membranes. It cleared the way to extreme stability required for astronomical practice on high mountain sites with heavy storms and ice formation. The storm Delta with 245 km/h 1-minute mean maximum at the location of the GREGOR caused no problems, nor did other storms afterwards. Opening and closing experiences up to wind speeds of 90 km/h were without problems. New technical developments were implemented and tested at the GREGOR dome, opening the way for application to much larger domes up to the 30 m diameter-class range.

  8. On the Survival of High-altitude Open Clusters within the Milky Way Galaxy Tides

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    It is a common assumption that high-altitude open clusters live longer compared to clusters moving close to the Galactic plane. This is because, at high altitudes, open clusters are far from the disruptive effects of in-plane substructures, such as spiral arms, molecular clouds, and the bar. However, an important aspect to consider in this scenario is that orbits of high-altitude open clusters will eventually cross the Galactic plane, where the vertical tidal field of the disk is strong. In this work, we simulate the interaction of open clusters with the tidal field of a detailed Milky Way Galactic model at different average altitudes and galactocentric radii. We find that the life expectancy of clusters decreases as the maximum orbital altitude increases and reaches a minimum at altitudes of approximately 600 pc. Clusters near the Galactic plane live longer because they do not experience strong vertical tidal shocks from the Galactic disk; then, for orbital altitudes higher than 600 pc, clusters again start to live longer due to the decrease in the number of encounters with the disk. With our study, we find that the compressive nature of the tides in the arms region and the bar play an important role in the survival of small clusters by protecting them from disruption: clusters inside the arms can live up to twice as long as those outside the arms at similar galactocentric distances.

  9. 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.

  10. 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.

  11. 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.

  12. Human-like characteristics for high degree of freedom robotic door-opening end-effector

    NASA Astrophysics Data System (ADS)

    Gray, Jeremy P.; Campagna, Frank

    2011-05-01

    In the field of military Unmanned Ground Vehicles (UGV's), military units are forced to sweep largely populated cities and towns in search of hostile enemies. These urban types of operations are referred to as MOUT (Military Operations on Urban Terrain). During urban operations, these UGV's encounter difficulties when opening doors. Current manipulator end effectors have these difficulties, because they are not designed to mimic human hand operations. This paper explains the mechanical nature of the Modular Universal Door Opening End-effector (MUDOE). MUDOE is a result of our development research to improve robotic manipulators ability to negotiate closed doors. The presented solution has the ability to mimic human hand characteristics when opening doors. The end-effector possesses an ability to maintain a high Degree of Freedom (DoF), and grasp the doorknob by applying equally distributed forces to all points of contact.

  13. 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…

  14. 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

  15. Laparoscopic Wedge Resection and Partial Nephrectomy - The Washington University Experience and Review of the Literature

    PubMed Central

    Elbahnasy, Abdelhamid M.; Clayman, Ralph 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

  16. Time-delay at higher genus in high-energy open string scattering*

    NASA Astrophysics Data System (ADS)

    Kuroki, T.; Rey, S.-J.

    2001-02-01

    We explore some aspects of causal time-delay in open string scattering studied recently by Seiberg, Susskind and Toumbas. By examining high-energy scattering amplitudes at higher order in perturbation theory, we argue that causal time-delay at /Gth order is /1/(G+1) times smaller than the time-delay at tree level. We propose a space-time interpretation of the result by utilizing the picture of the high-energy open string scattering put forward by Gross and Mañes. We argue that the phenomenon of reduced time-delay is attributed to the universal feature of the space-time string trajectory in high-energy scattering that string shape at higher order remains the same as that at tree level but overall scale is reduced. We also discuss implications to the space-time uncertainty principle and make brief comments on causal time-delay behavior in space/time noncommutative field theory.

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. Seismicity of the forearc marginal wedge (accrertionary prism)

    SciTech Connect

    Chen, A.T.; Frohlich, C.; Latham, G.V.

    1982-05-10

    Three different types of seismic data have been examined for seismic events occurring within the zone called the accreted wedge or forearc marginal wedge that underlies the inner trench wall of some arcs. These types of data are (1) teleseismically recorded earthquakes that have been reported in the literature as occurring in major arc-trench regions; these events fail to demonstrate that earthquakes occur within the accreted wedge because the uncertainty of focal depth usually exceeds the depth dimension of the accreted wedge; these data include many tsunamigenic earthquakes, (2) local earthquakes located by combined ocean bottom seismograph and land networks in the arc-trench region in the New Hebrides and the central and eastern Aleutian Trench; none of the more reliable of these hypocenters lies within the accreted wedge; (3) S-P intervals measured at stations on islands located on the outer ridge or at ocean bottom seismograph stations on the forearc marginal wedge; these data do not show the existence of events occurring within the accreted wedge; e.g., from 18 ocean bottom seismograph stations with a cumulative operation time of about 1 year, the smallest S-P time is about 2.5 s for events in the New Hebrides and about 4 s for events in the Adak and Kodiak regions. We found no S-P time smaller than 2 s from 6 years of seismograms recorded at Middleton Island, Alaska, and no S-P time smaller than 4 s from 25 years of seismograms recorded on Barbados. All of the events could have occured outside the forearc marginal wedge.

  3. Stereoscopic Display on Computer Monitor Using a Single Wedge Prism

    NASA Astrophysics Data System (ADS)

    Park, Tae-Soo; Park, Chan-Young; Lee, Han-Bae; Park, Seung-Han

    2002-02-01

    We propose a novel stereoscopic display technique which uses only a single wedge prism. It can provide good depth perception from a stereoscopic pair image displayed on a computer monitor. One element of the stereoscopic pair image is inversely distorted to correct the deformation induced by the wedge prism. The computer simulation and experimental demonstration show that this technique can be successfully applied to the Internet environment.

  4. Orientation of optic axis in wedged photorefractive crystals

    NASA Astrophysics Data System (ADS)

    Kos, Konstantine; Siahmakoun, Azad Z.

    1996-02-01

    A holographic method for finding the orientation of the optic axis of uniaxial photorefractive crystals is proposed. A theoretical procedure for determining the wedge angle of such crystals has also been developed. Two BaTiO 3 crystals grown by the same vender are examined and the resulting measurements lead to the values of wedge angle with an accuracy of about ±0.1°.

  5. 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.

  6. AZOrange - High performance open source machine learning for QSAR modeling in a graphical programming environment

    PubMed Central

    2011-01-01

    Background Machine learning has a vast range of applications. In particular, advanced machine learning methods are routinely and increasingly used in quantitative structure activity relationship (QSAR) modeling. QSAR data sets often encompass tens of thousands of compounds and the size of proprietary, as well as public data sets, is rapidly growing. Hence, there is a demand for computationally efficient machine learning algorithms, easily available to researchers without extensive machine learning knowledge. In granting the scientific principles of transparency and reproducibility, Open Source solutions are increasingly acknowledged by regulatory authorities. Thus, an Open Source state-of-the-art high performance machine learning platform, interfacing multiple, customized machine learning algorithms for both graphical programming and scripting, to be used for large scale development of QSAR models of regulatory quality, is of great value to the QSAR community. Results This paper describes the implementation of the Open Source machine learning package AZOrange. AZOrange is specially developed to support batch generation of QSAR models in providing the full work flow of QSAR modeling, from descriptor calculation to automated model building, validation and selection. The automated work flow relies upon the customization of the machine learning algorithms and a generalized, automated model hyper-parameter selection process. Several high performance machine learning algorithms are interfaced for efficient data set specific selection of the statistical method, promoting model accuracy. Using the high performance machine learning algorithms of AZOrange does not require programming knowledge as flexible applications can be created, not only at a scripting level, but also in a graphical programming environment. Conclusions AZOrange is a step towards meeting the needs for an Open Source high performance machine learning platform, supporting the efficient development of

  7. 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.

  8. Optical refractometry based on Fresnel diffraction from a phase wedge.

    PubMed

    Tavassoly, M Taghi; Saber, Ahad

    2010-11-01

    A method that utilizes the Fresnel diffraction of light from the phase step formed by a transparent wedge is introduced for measuring the refractive indices of transparent solids, liquids, and solutions. It is shown that, as a transparent wedge of small apex angle is illuminated perpendicular to its surface by a monochromatic parallel beam of light, the Fresnel fringes, caused by abrupt change in refractive index at the wedge lateral boundary, are formed on a screen held perpendicular to the beam propagation direction. The visibility of the fringes varies periodically between zero and 1 in the direction normal to the wedge apex. For a known or measured apex angle, the wedge refractive index is obtained by measuring the period length by a CCD. To measure the refractive index of a transparent liquid or solution, the wedge is installed in a transparent rectangle cell containing the sample. Then, the cell is illuminated perpendicularly and the visibility period is measured. By using modest optics, one can measure the refractive index at a relative uncertainty level of 10(-5). There is no limitation on the refractive index range. The method can be applied easily with no mechanical manipulation. The measuring apparatus can be very compact with low mechanical and optical noises.

  9. Anomalous intra-plate high-Mg andesites in the Choshi area (Chiba, Central Japan) produced during early stages of Japan Sea opening?

    NASA Astrophysics Data System (ADS)

    Hoang, Nguyen; Yamamoto, Takahiro; Itoh, Jun'ichi; Flower, Martin F. J.

    2009-10-01

    Geochemical and isotopic data are reported for 20 Ma high-magnesian andesite (HMA) lavas erupted on the forearc side of Central Japan in the Choshi coastal area (Chiba). Rarely olivine-phyric (< 3% vol), these rocks have ca. 56 wt.% SiO 2, Na 2O ranging between 3.9 and 4.2 wt.%, and relatively low K 2O/Na 2O ratios (ca. 0.44). Their Mg numbers are relatively high (ca. 0.64) and matched by high Cr (> 345 ppm), high Sr (> 520 ppm), high Sr/Y (ca. 30), and high [La/Yb] N (> 8), conforming to the definition of low-silica adakites, transitional in character to HMA. However, despite slight negative Nb and Ta 'troughs' in a few samples, their incompatible element distribution patterns appear closer to those of intra-plate basalts, apparently confirming previous suggestions that terms such as HMA and adakite cover a diverse range of compositions. Enriched in radiogenic Sr and Nd (ca. 0.7040 to 0.7043 and 0.5128 to 0.51275, respectively), the Choshi HMA shows relatively low 206Pb/ 204Pb (18.25 to 18.35) and 208Pb/ 204Pb (38.37 to 38.48) ratios, resembling those of late Miocene intra-plate basalts in the Japan Sea and SW Japan. In this regard the Choshi HMA differs from those of the 'classic' Middle Miocene (14 to 12 Ma) HMA described from the Setouchi volcanic belt (e.g. Tatsumi, 1981), a short distance to the west which also shows relative high K contents. Although HMAs have been generally attributed to subduction-related processes, the lack of high field strength element (HFSE) depletions cf. large ionic lithophile elements (LILE) in most Choshi HMA suggests an absence of so-called 'subduction signatures'. Accordingly, we suggest that the Choshi HMA probably tapped a fertile (asthenospheric) region of the convecting mantle wedge, primitive melt products having acquired HMA-like character as a result of shallow level modification by interaction with lithospheric components, aided by thermal input resulting from mantle extrusion, during the early stages of Japan Sea opening

  10. Further research on high open circuit voltage in silicon solar cells

    NASA Technical Reports Server (NTRS)

    Spitzer, M. B.; Keavney, C. J.

    1985-01-01

    The results of a new research on the use of controlled dopant profiles and oxide passivation to achieve high open circuit voltage V sub oc in silicon solar cells is presented. Ion implantation has been used to obtain nearly optimal values of surface dopant concentration. The concentrations are selected so as to minimize heavy doping effects and thereby provide both high blue response and high V sub oc ion implantation technique has been successfully applied to fabrication of both n-type and p-type emitters. V sub oc of up to 660 mV is reported and AMO efficiency of 16.1% has been obtained.

  11. 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

  12. Study of Cavitation in Wakes of Circular Cylinders and Symmetric Wedges Using X-ray Densitometry

    NASA Astrophysics Data System (ADS)

    Koot, Joachim; Wu, Juliana; Ganesh, Harish; Ceccio, Steven

    2016-11-01

    Cavitation in wakes behind canonical objects can exhibit variation in Strouhal number with a reduction in cavitation number. Circular cylinders of two diameters and symmetric wedges with a wedge angle of 15, 30, and 60 degrees are used to study cavitation in their wakes using X-ray densitometry. Using high speed video and X-ray densitometry, the nature of cavitation is studied in near-wake and a part of the far-wake region. In addition, acoustic measurements are also carried out to understand the spectral content of such wake cavities. Based on void fraction flow field and high-speed video measurements, the effect of cavitation on the Kármán vortex street spacing in the far wake region is studied. The results are the interpreted to explain the physical mechanisms responsible for the observed change in Strouhal number. Office of Naval Research.

  13. Relationship between the blue response and open-circuit voltage of high performance silicon solar cells

    NASA Technical Reports Server (NTRS)

    Green, M. A.; Blakers, A. W.

    1983-01-01

    The relationship between the response at blue wavelengths and the open-circuit voltage of high performance silicon solar cells with a virtually 'transparent' emitter is analyzed. It is shown that a one-dimensional cell model cannot simultaneously model the optical collection properties and operating characteristics of such cells. The analysis highlights the importance of surface conditions and shows that previous conclusions regarding bounds on Auger coefficients imposed by correlating these parameters must be treated with caution.

  14. Results of Open-Heart Surgery in High-Risk Patients

    PubMed Central

    Chafizadeh, G.N.

    1982-01-01

    Of 732 patients undergoing open heart surgery in Pars Hospital Tehran, 127 were classified in a high risk surgical category. Of these, there were 19 mortalities. Three main groups of patients were studied; Group I consisted of those with congenital disorders, such as Ebstein's anomaly and the medical-necrosis type of ascending aneurysms; Group II consisted of reoperaton cases; and Group III was composed of patients with cardiomegaly who required double or triple-valve surgery. PMID:15226817

  15. 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

  16. 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

  17. 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.

  18. SU-E-T-362: Enhanced Dynamic Wedge Output Factors for Varian 2300CD and the Case for a Reference Database

    SciTech Connect

    Njeh, C

    2015-06-15

    Purpose: Dose inhomogeneity in treatment planning can be compensated using physical wedges. Enhanced dynamic wedges (EDW) were introduced by Varian to overcome some of the short comings of physical wedges. The objectives of this study were to measure EDW output factors for 6 MV and 20 MV photon energies for a Varian 2300CD. Secondly to review the literature in terms of published enhanced dynamic wedge output factors (EDWOF) for different Varian models and thereby adding credence to the case of the validity of reference databases. Methods: The enhanced dynamic wedge output factors were measured for the Varian 2300CD for both 6 MV and 20 MV photon energies. Twelve papers with published EDWOF for different Varian Linac models were found in the literature. Results: The EDWOF for 6 MV varied from 0.980 for a 5×5 cm 10 degree wedge to 0.424 for 20×20 cm 60 degree wedge. Similarly for 20 MV, the EDWOF varied from 0.986 for 5×5 cm 10 degree wedge to 0.529 for 20×20 cm 60 degree wedge. EDWOF are highly dependent on field size. Comparing our results with the published mean, we found an excellent agreement for 6 MV EDWOF with the percentage differences ranging from 0.01% to 0.57% with a mean of 0.03%. The coefficient of variation of published EDWOF ranged from 0.17% to 0.85% and 0.1% to 0.9% for the for 6 MV and 18MV photon energies respectively. This paper provides the first published EDWOF for 20 MV photon energy. In addition, we have provided the first compendium of EDWOFs for different Varian linac models. Conclusion: The consistency of EDWOF across models and institution provide further support that, a standard data set of basic photon and electron dosimetry could be established, as a guide for future commissioning, beam modeling and quality assurance purposes.

  19. Measured Two-Dimensional Ice-Wedge Polygon Thermal Dynamics

    NASA Astrophysics Data System (ADS)

    Cable, William; Romanovsky, Vladimir; Busey, Robert

    2016-04-01

    Ice-wedge polygons are perhaps the most dominant permafrost related features in the arctic landscape. The microtopography of these features, that includes rims, troughs, and high and low polygon centers, alters the local hydrology, as water tends to collect in the low areas. During winter, wind redistribution of snow leads to an increased snowpack depth in the low areas, while the slightly higher areas often have very thin snow cover, leading to differences across the landscape in vegetation communities and soil moisture between higher and lower areas. These differences in local surface conditions lead to spatial variability of the ground thermal regime in the different microtopographic areas and between different types of ice-wedge polygons. To study these features in depth, we established temperature transects across four different types of ice-wedge polygons near Barrow, Alaska. The transects were composed of five vertical array thermistor probes (VATP) beginning in the center of each polygon and extending through the trough to the rim of the adjacent polygon. Each VATP had 16 thermistors from the surface to a depth of 1.5 m. In addition to these 80 subsurface temperature measurement points per polygon, soil moisture, thermal conductivity, heat flux, and snow depth were all measured in multiple locations for each polygon. Above ground, a full suite of micrometeorological instrumentation was present at each polygon. Data from these sites has been collected continuously for the last three years. We found snow cover, timing and depth, and active layer soil moisture to be major controlling factors in the observed thermal regimes. In troughs and in the centers of low-center polygons, the combined effect of typically saturated soils and increased snow accumulation resulted in the highest mean annual ground temperatures (MAGT). Additionally, these areas were the last part of the polygon to refreeze during the winter. However, increased active layer thickness was not

  20. 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

  1. 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

    2013-11-05

    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.

  2. 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.

  3. 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

  4. Characteristics of a rat model of an open craniocerebral injury at simulated high altitude

    PubMed Central

    Yu, An-Yong; Xu, Quan-Hong; Hu, Sheng-Li; Li, Fei; Chen, Yu-Jie; Yin, Yi; Zhu, Gang; Lin, Jiang-Kai

    2014-01-01

    To establish a rat model of an open craniocerebral injury at simulated high altitude and to examine the characteristics of this model. Rats were divided randomly into a normobaric group and a high-altitude group and their corresponding control groups. A rat model of an open craniocerebral injury was established with a nail gun shot. Simulated high-altitude conditions were established with a hypobaric chamber at 0.6 ATA to mimic pressure at an altitude of 4000 m. Mortality, brain water content (BWC), Evans blue content, pathology, regional cerebral blood flow (rCBF), partial pressure of brain tissue oxygen (PbtO2), and brainstem auditory-evoked potential were observed after injury. The mortality of the high-altitude group was significantly greater than that of the normobaric group within 72 h after injury (P<0.05). BWC and Evans blue content increased by 48 h after injury (P<0.05); pathological changes in damaged brains were more serious. In contrast, rCBF and PbtO2 had decreased markedly by 72 h (P<0.01); brainstem auditory-evoked potential values were significantly prolonged (P<0.05). Moreover, an inverse correlation between rCBF and BWC and a positive correlation between rCBF and PbtO2 were found. The rat model of an open craniocerebral injury at simulated high altitude can be established successfully using a nail gun shot and a hypobaric chamber. The injury characteristics at high altitude were more serious, rapid, and prolonged than those in the normobaric group. PMID:25191925

  5. Remote Sensing of Open Water in Northern High Latitudes for use in Hydrologic Modeling

    NASA Astrophysics Data System (ADS)

    Podest, E.; McDonald, K. C.; Kimball, J.; Maumenee, N.; Bohn, T.; Lettenmaier, D.; Bowling, L.

    2007-12-01

    In the northern high latitudes open water bodies are common landscape features, having a large influence on hydrologic processes as well as surface-atmosphere carbon exchange and associated impacts on global climate. It is therefore of great importance to assess their spatial extent and temporal character in order to improve hydrologic and ecosystem process modeling. Spaceborne synthetic aperture radar (SAR) is an effective tool for this purpose since it is particularly sensitive to surface water and it can monitor large inaccessible areas on a temporal basis regardless of atmospheric conditions or solar illumination. We employ multi-temporal L-band SAR data from the Japanese Earth Remote Sensing Satellite (JERS-1) and ALOS PALSAR to map open water bodies across Alaska and Eurasia. A supervised decision tree-based classification approach was used to generate open water maps. For Alaska, we assembled regional-scale monthly JERS-1 SAR mosaics from data acquired during 1998. Digital elevation model (DEM) terrain and slope information were also employed in the decision tree classifier. These supplementary data aided significantly in improving classification performance in topographically complex regions where radar shadowing was prevalent. For study regions in Eurasia, PALSAR data was used in conjunction with JERS-1 imagery to map spatial patterns and seasonal variability in open water characteristics over selected study basins. These results were examined in relation to regional topographic and land cover characteristics. Classification results were also evaluated relative to other open water and land cover classification maps derived from Landsat, AVHRR, MODIS and SRTM. This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology; at the University of Montana; at the University of Washington; and at Purdue University under contract with the National Aeronautics and Space Administration.

  6. Coulomb theory applied to accretionary and nonaccretionary wedges: Possible causes for tectonic erosion and/or frontal accretion

    NASA Astrophysics Data System (ADS)

    Lallemand, Serge E.; Schnürle, Philippe; Malavieille, Jacques

    1994-06-01

    Based on observations from both modem convergent margins and sandbox modeling, we examine the possible conditions favoring frontal accretion and/or frontal and basal tectonic erosion. Mean characteristic parameters (μ, μ*b and λ) are used to discuss the mechanical stability of 28 transects across the frontal part of convergent margins where the Coulomb theory is applicable. Natural observations reveal that "typical accretionary wedges" are characterized by low tapers with smooth surface slope and subducting plate, low convergence rates and thick trench sediment, while "nonaccretionary wedges" display large tapers with irregular surface slopes and rough subducting plate, high convergence rates and almost no trench fill. Sandbox experiments were performed to illustrate the effects of seamounts/ridges in the subduction zone on the deformation of an accretionary wedge. These experiments show that a wedge of sand is first trapped and pushed in front of the seamount which acts as a moving bulldozer. This is followed by a tunnelling effect of the subducting seamount through the frontal wedge material, which results in considerable sand reworking. At an advanced subduction stage, the décollement jumps back from a high level in the wedge to its former basal position. We conclude that a high trench sedimentation rate relative to the convergence rate leads to frontal accretion. In contrast, several conditions may favor tectonic erosion of the upper plate. First, oceanic features, such as grabens, seamounts or ridges, may trap upper plate material during their subduction process. Second, destabilization of the upper plate material by internal fluid overpressuring causing hydrofracturing is probably another important mechanism.

  7. 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.

  8. Convergence of high order perturbative expansions in open system quantum dynamics

    NASA Astrophysics Data System (ADS)

    Xu, Meng; Song, Linze; Song, Kai; Shi, Qiang

    2017-02-01

    We propose a new method to directly calculate high order perturbative expansion terms in open system quantum dynamics. They are first written explicitly in path integral expressions. A set of differential equations are then derived by extending the hierarchical equation of motion (HEOM) approach. As two typical examples for the bosonic and fermionic baths, specific forms of the extended HEOM are obtained for the spin-boson model and the Anderson impurity model. Numerical results are then presented for these two models. General trends of the high order perturbation terms as well as the necessary orders for the perturbative expansions to converge are analyzed.

  9. Opening-mode fracture in siliceous mudstone at high homologous temperature—effect of surface forces

    NASA Astrophysics Data System (ADS)

    Eichhubl, Peter; Aydin, Atilla; Lore, Jason

    In analogy to high-temperature sintering of ceramics and metal powder compacts, the formation of opening-mode fractures in siliceous mudstone during natural in-situ combustion of hydrocarbons is attributed to contractile surface forces between mineral grains and an interstitial melt phase. A comparison between bulk density increase during sintering and created fracture space indicates that fracturing resulted from contraction of the rock matrix due to porosity reduction, grain-scale mass transfer, and high-temperature mineral formation. It is suggested that contractile surface forces between mineral grains and between mineral grains and pore fluid contribute to subcritical fracture formation under a wide range of subsurface conditions.

  10. 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.

  11. Seismic reflection images of the accretionary wedge of Costa Rica

    SciTech Connect

    Shipley, T.H.; Stoffa, P.L. ); McIntosh, K.; Silver, E.A. )

    1990-05-01

    The large-scale structure of modern accretionary wedges is known almost entirely from seismic reflection investigations using single or grids of two-dimensional profiles. The authors will report on the first three-dimensional seismic reflection data volume collected of a wedge. This data set covers a 9-km-wide {times} 22-km-long {times} 6-km-thick volume of the accretionary wedge just arcward of the Middle America Trench off Costa Rica. The three-dimensional processing has improved the imaging ability of the multichannel data, and the data volume allows mapping of structures from a few hundred meters to kilometers in size. These data illustrate the relationships between the basement, the wedge shape, and overlying slope sedimentary deposits. Reflections from within the wedge define the gross structural features and tectonic processes active along this particular convergent margin. So far, the analysis shows that the subdued basement relief (horst and graben structures seldom have relief of more than a few hundred meters off Costa Rica) does affect the larger scale through going structural features within the wedge. The distribution of mud volcanoes and amplitude anomalies associated with the large-scale wedge structures suggests that efficient fluid migration paths may extend from the top of the downgoing slab at the shelf edge out into the lower and middle slope region at a distance of 50-100 km. Offscraping of the uppermost (about 45 m) sediment occurs within 4 km of the trench, creating a small pile of sediments near the trench lower slope. Underplating of parts of the 400-m-thick subducted sedimentary section begins at a very shallow structural level, 4-10 km arcward of the trench. Volumetrically, the most important accretionary process is underplating.

  12. 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

  13. Modification of the Himalayan Orogenic Wedge by Late Cenozoic Southeastward Flow of Tibet

    NASA Astrophysics Data System (ADS)

    Hodges, K. V.; Whipple, K. X.; Kirby, E.; Arrowsmith, R.; Shirzaei, M.

    2014-12-01

    Continental plateaus are reservoirs of excess gravitational energy that can influence the late-stage geodynamic evolution of adjacent orogenic wedges. In the central Himalaya (80-88˚E), most late Cenozoic deformation has involved roughly N-S shortening within the Himalayan orogenic wedge. Within this region, all 1976-2014 Mw 5 and larger earthquakes had thrust mechanisms associated with slip along major arc-parallel structures within or at the base of the orogenic wedge. In contrast, the segment of the wedge between 88˚E and 91˚E - including easternmost Nepal, the Sikkim region of India, and Bhutan - is characterized by a complex deformation field that includes thrusting on arc-parallel wedge structures but also transcurrent faulting at high angles to the Himalayan arc. In fact, over the same 1976-2014 period, all but one of the Mw 5 and larger earthquakes in this region had transcurrent fault mechanisms, mostly consistent with dextral strike-slip along NW-striking faults. We refer to this region as the central-eastern Himalayan transition zone. Although direct field evidence of the surface breaks of these faults has not been established, the orientations of nodal planes of large earthquakes, as well as alignments of microearthquake arrays, suggest that they may connect northward to a discontinuous family of arc-parallel faults - most showing evidence for oblique slip, with variable normal and dextral-transcurrent components - which we interpret as the long-term structural manifestation of the boundary between the distinctive modern strain fields of Tibet (E-W extension) and the central Himalaya (N-S shortening). In addition, transverse faults of the central-eastern Himalayan transition zone may project southward, beneath sediments near the Ganges and Bhramaputra confluence, as dextral tear faults linking the active thrust front of the central Himalaya to the active thrust front of the Shillong Plateau in northeastern India. We hypothesize that the broadening of

  14. 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).

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. Resonant wedge-plasmon modes in single-crystalline gold nanoplatelets

    NASA Astrophysics Data System (ADS)

    Gu, Lin; Sigle, Wilfried; Koch, Christoph T.; Ögüt, Burcu; van Aken, Peter A.; Talebi, Nahid; Vogelgesang, Ralf; Mu, Jianlin; Wen, Xiaogang; Mao, Jian

    2011-05-01

    Using energy-filtered transmission electron microscopy we measured surface-plasmon resonances of gold nanoplatelets with different shapes and edge lengths at high spatial resolution. We find equidistant maxima of the energy-loss probability along the platelet edges. The plasmon dispersion of the different geometries is very similar, i.e., hardly dependent on specimen shape. The experimental results are verified by means of finite-difference time-domain calculations which reveal the presence of wedge-plasmon polaritons propagating along the platelet edges. At platelet corners, apart from radiative losses, wedge-plasmon polaritons are partially reflected or transmitted to neighboring edges. The interference of all these contributions leads to the observed plasmon resonance modes. This is an essential step towards a thorough understanding of plasmon eigenmodes in prismatic nanoplatelets.

  1. 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.

  2. Body radiation exposure in breast cancer radiotherapy: Impact of breast IMRT and virtual wedge compensation techniques

    SciTech Connect

    Woo, Tony; Pignol, Jean-Philippe . E-mail: Jean-Philippe.Pignol@sw.ca; Rakovitch, Eileen; Vu, Toni; Hicks, Deanna; O'Brien, Peter; Pritchard, Kathleen

    2006-05-01

    Purpose: Recent reports demonstrate a dramatically increased rate of secondary leukemia for breast cancer patients receiving adjuvant high-dose anthracycline and radiotherapy, and that radiation is an independent factor for the development of leukemia. This study aimed to evaluate the radiation body exposure during breast radiotherapy and to characterize the factors associated with an increased exposure. Patients and Methods: In a prospective cohort of 120 women, radiation measurements were taken from four sites on the body at the time of adjuvant breast radiotherapy. Multiple regression analysis was performed to analyze patient and treatment factors associated with the amount of scattered radiation. Results: For standard 50 Gy breast radiotherapy, the minimal dose received by abdominal organs is on average 0.45 Gy, ranging from 0.06 to 1.55 Gy. The use of physical wedges as a compensation technique was the most significant factor associated with increased scattered dose (p < 0.001), resulting in approximately three times more exposure compared with breast intensity-modulated radiation therapy (IMRT) and dynamic wedge. Conclusions: The amount of radiation that is scattered to a patient's body is consistent with exposure reported to be associated with excess of leukemia. In accordance with the As Low As Reasonably Achievable (ALARA) principle, we recommend using breast IMRT or virtual wedging for the radiotherapy of breast cancer receiving high-dose anthracycline chemotherapy.

  3. 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.

  4. 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.

  5. The Cu2ZnSnS4 solar cell with high open circuit voltage

    NASA Astrophysics Data System (ADS)

    Yang, Min; Ma, Xun; Jiang, Zhi; Li, Zhishan; Liu, Sijia; Lu, Yilei; Wang, Shurong

    2017-03-01

    In this paper, the effects of two different sulfurization processes on the CZTS films were investigated, and the results indicated that a rapid high-temperature crystallization process after sulfurization was beneficial for CZTS thin films to obtain a compact and flat surface with large grains. However, a common sulfurization without rapid high-temperature crystallization process would easily lead to undesirable properties of films, such as rough surface with pin holes, which degenerate the performance of devices. Cu2ZnSnS4 (CZTS) solar cell based on a rapid high-temperature process after sulfurization achieved a high open circuit voltage of 722 mV and the best efficiency 3.32% was obtained.

  6. [Evaluation of the bite block wedged between the maxillary and mandibular molars].

    PubMed

    Katoh, H; Nishiyama, J; Takiguchi, M; Yamamoto, M; Fujita, K; Yamasaki, Y

    1996-12-01

    The purpose of this study was to compare our original bite block (T-X Block) wedged between the maxillary and mandibular molars, with the standard gum bite block, in 200 patients whose tracheas were intubated. During emergence from isoflurane anesthesia, no trouble occurred in T-X Block group (n = 100). On the other hand, lip damage and ejection of the bite block were found in 11 and 10 cases, respectively, in gum bite block group (n = 100). As another study, an opening between the maxillary and mandibular incisor edges was measured with T-X Block placed in twenty patients under general anesthesia. The inter-incisal distances in one way of using it as a smaller wedge and in the other way as a bigger one were 21.6 +/- 2.4 and 25.2 +/- 2.6 mm, respectively. Those values were significantly larger than thickness of the gum bite block. T-X Block is very useful because its use causes no complications and makes it easier to insert a naso-gastric tube as well as to clean the oral cavity with suction by giving a larger opening of the mouth.

  7. 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.

  8. Numerical simulation of flow around a simplified high-speed train model using OpenFOAM

    NASA Astrophysics Data System (ADS)

    Ishak, I. A.; Ali, M. S. M.; Shaikh Salim, S. A. Z.

    2016-10-01

    Detailed understanding of flow physics on the flow over a high-speed train (HST) can be accomplished using the vast information obtained from numerical simulation. Accuracy of any simulation in solving and analyzing problems related to fluid flow is important since it measures the reliability of the results. This paper describes a numerical simulation setup for the flow around a simplified model of HST that utilized open source software, OpenFOAM. The simulation results including pressure coefficient, drag coefficient and flow visualization are presented and they agreed well with previously published data. This shows that OpenFOAM software is capable of simulating fluid flows around a simplified HST model. Additionally, the wall functions are implemented in order to minimize the overall number of grid especially near the wall region. This resulted in considerably smaller numbers of mesh resolution used in the current study compared to previous work, which leads to achievement of much reasonable time simulation and consequently reduces the total computational effort without affecting the final outcome.

  9. Open Source High Content Analysis Utilizing Automated Fluorescence Lifetime Imaging Microscopy

    PubMed Central

    Warren, Sean C.; Alibhai, Dominic; West, Lucien; Kumar, Sunil; Alexandrov, Yuriy; Munro, Ian; Garcia, Edwin; McGinty, James; Talbot, Clifford; Serwa, Remigiusz A.; Thinon, Emmanuelle; da Paola, Vincenzo; Murray, Edward J.; Stuhmeier, Frank; Neil, Mark A. A.; Tate, Edward W.; Dunsby, Christopher; French, Paul M. W.

    2017-01-01

    We present an open source high content analysis instrument utilizing automated fluorescence lifetime imaging (FLIM) for assaying protein interactions using Förster resonance energy transfer (FRET) based readouts of fixed or live cells in multiwell plates. This provides a means to screen for cell signaling processes read out using intramolecular FRET biosensors or intermolecular FRET of protein interactions such as oligomerization or heterodimerization, which can be used to identify binding partners. We describe here the functionality of this automated multiwell plate FLIM instrumentation and present exemplar data from our studies of HIV Gag protein oligomerization and a time course of a FRET biosensor in live cells. A detailed description of the practical implementation is then provided with reference to a list of hardware components and a description of the open source data acquisition software written in µManager. The application of FLIMfit, an open source MATLAB-based client for the OMERO platform, to analyze arrays of multiwell plate FLIM data is also presented. The protocols for imaging fixed and live cells are outlined and a demonstration of an automated multiwell plate FLIM experiment using cells expressing fluorescent protein-based FRET constructs is presented. This is complemented by a walk-through of the data analysis for this specific FLIM FRET data set. PMID:28190060

  10. 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.

  11. On the validity of 2D critical taper theory in 3D wedges: defining a lateral deformation length scale

    NASA Astrophysics Data System (ADS)

    Leever, Karen; Oncken, Onno; Thorden Haug, Øystein

    2015-04-01

    For 2D critical taper theory to be applicable to 3D natural cases, cylindric deformation is a requirement. The assumption of cylindricity is violated in case of localized perturbations (subducting seamount, localized sedimentation) or due to a lateral change in decollement strength or depth. In natural accretionary wedges and fold-and-thrust belts, along strike changes may occur in a variety of ways: geometrical (due to a protruding indenter or a change in decollement depth), through a lateral change in basal friction (leading to laterally different tapers), or through a change in surface slope (by strongly localized fan sedimentation on accretionary wedges). Recent numerical modelling results (Ruh et al., 2013) have shown that lateral coupling preferentially occurs for relatively small perturbations, i.e. the horizontal shear stress caused by the perturbation is supported by the system. Lateral linking of the wedge in front of a protruding indenter to the wedge in front of the trailing edge of the back stop leads to curved thrust fronts and importantly it has been noted that even outside the curved zone, where the wedge front is again parallel to the direction of tectonic transport, the lateral effect is still evident: both tapers are different from the analytical prediction. We present results from a 3D analogue modelling parameter study to investigate this behavior more quantitatively, with the objective of empirically finding a lateral length scale of deformation in brittle contractional wedges. For a given wedge strength (angle of internal friction), we infer this to be a function of the size (width) of the perturbation and its magnitude (difference in basal friction). To this end we run different series of models in which we systematically vary the width and/or magnitude of a local perturbation. In the first series, the width of a zone of high basal friction is varied, in the second series we vary the width of an indenter and in the third series

  12. Facilitating the openEHR approach - organizational structures for defining high-quality archetypes.

    PubMed

    Kohl, Christian Dominik; Garde, Sebastian; Knaup, Petra

    2008-01-01

    Using openEHR archetypes to establish an electronic patient record promises rapid development and system interoperability by using or adopting existing archetypes. However, internationally accepted, high quality archetypes which enable a comprehensive semantic interoperability require adequate development and maintenance processes. Therefore, structures have to be created involving different health professions. In the following we present a model which facilitates and governs distributed but cooperative development and adoption of archetypes by different professionals including peer reviews. Our model consists of a hierarchical structure of professional committees and descriptions of the archetype development process considering these different committees.

  13. Open Dislocation of the High Ankle Joint After Fibular Graft Harvesting.

    PubMed

    Anđelković, Slađana Z; Vučković, Čedo Đ; Palibrk, Tomislav D; Milutinović, Suzana M; Bumbaširević, Marko Ž

    2015-01-01

    The free microvascular fibula and soft tissue transfer has become a widely used method for reconstruction of different regions. Donor site morbidity for free fibula microvascular flaps has generally been reported to be low, or at least acceptable. We describe the case of a patient who underwent vascularized free fibula graft harvest for mandibular reconstruction. After 21 months, he had sustained an open dislocation of the left high ankle joint during recreational sports activity. We did not found such case in the published data.

  14. 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

  15. 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.

  16. CFD Simulations of the IHF Arc-Jet Flow: Compression-Pad/Separation Bolt Wedge Tests

    NASA Technical Reports Server (NTRS)

    Gokcen, Tahir; Skokova, Kristina A.

    2017-01-01

    This paper reports computational analyses in support of two wedge tests in a high enthalpy arc-jet facility at NASA Ames Research Center. These tests were conducted using two different wedge models, each placed in a free jet downstream of a corresponding different conical nozzle in the Ames 60-MW Interaction Heating Facility. Panel test articles included a metallic separation bolt imbedded in the compression-pad and heat shield materials, resulting in a circular protuberance over a flat plate. As part of the test calibration runs, surface pressure and heat flux measurements on water-cooled calibration plates integrated with the wedge models were also obtained. Surface heating distributions on the test articles as well as arc-jet test environment parameters for each test configuration are obtained through computational fluid dynamics simulations, consistent with the facility and calibration measurements. The present analysis comprises simulations of the non-equilibrium flow field in the facility nozzle, test box, and flow field over test articles, and comparisons with the measured calibration data.

  17. 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.

  18. Trench-parallel anisotropy produced by serpentine deformation in the hydrated mantle wedge.

    PubMed

    Katayama, Ikuo; Hirauchi, Ken-ichi; Michibayashi, Katsuyoshi; Ando, Jun-ichi

    2009-10-22

    Seismic anisotropy is a powerful tool for detecting the geometry and style of deformation in the Earth's interior, as it primarily reflects the deformation-induced preferred orientation of anisotropic crystals. Although seismic anisotropy in the upper mantle is generally attributed to the crystal-preferred orientation of olivine, the strong trench-parallel anisotropy (delay time of one to two seconds) observed in several subduction systems is difficult to explain in terms of olivine anisotropy, even if the entire mantle wedge were to act as an anisotropic source. Here we show that the crystal-preferred orientation of serpentine, the main hydrous mineral in the upper mantle, can produce the strong trench-parallel seismic anisotropy observed in subduction systems. High-pressure deformation experiments reveal that the serpentine c-axis tends to rotate to an orientation normal to the shear plane during deformation; consequently, seismic velocity propagating normal to the shear plane (plate interface) is much slower than that in other directions. The seismic anisotropy estimated for deformed serpentine aggregates is an order of magnitude greater than that for olivine, and therefore the alignment of serpentine in the hydrated mantle wedge results in a strong trench-parallel seismic anisotropy in the case of a steeply subducting slab. This hypothesis is also consistent with the presence of a hydrous phase in the mantle wedge, as inferred from anomalously low seismic-wave velocities.

  19. 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

  20. Hyaluronan Based Heparin Free Coated Open and Closed Extracorporeal Circuits for High Risk Coronary Revascularization

    PubMed Central

    Gunaydin, Serdar; Ucar, Halil Ibrahim; Serter, Tanzer; McCusker, Kevin; Ozcelik, Gokhan; Salman, Nevriye; Yorgancioglu, Ali Cem

    2010-01-01

    Abstract: This prospective randomized study compares the inflammatory response and fibrinolytic activation of fully coated/uncoated and open/closed extracorporeal circuits (ECC) in high risk patients. Over a 2-month period, 48 patients with EuroSCOREs 6 or greater undergoing coronary revascularization were pro spectively randomized to one of the four perfusion protocols: Group 1: Closed and totally hyaluronan based heparin free coated (Vision HFO-GBS-HF™, Gish Biomedical, Rancho Santa Margarita, CA) ECC with a soft-shell coated venous reservoir (SVR11S2-HFC™, Gish Biomedical) and a hard-shell cardiotomy (CAPVRF44, Gish Biomedical) (n = 12); Group 2: Closed and totally uncoated identical ECC with soft-shell uncoated venous reservoir and a hard-shell cardiotomy (n = 12); Group 3: Open, totally hyaluronan based heparin free coated ECC (n = 12); and Group 4: Control-open, uncoated ECC (n = 12). Blood samples were collected at T1: Baseline; T2: 15 minutes after cardiopulmonary bypass (CPB) initiation; T3: before cessation of CPB; T4: 15 minutes after protamine reversal, and T5: in the intensive care unit. Serum IL-6 levels were significantly lower at T2 in all study groups, at T3 for coated groups, and T4 for closed+coated group (p < .05 versus control). Creatine kinase M-band (MB) levels in coronary sinus blood demonstrated well preserved myocardium after CPB in both coated groups versus Control (p < .05). Neutrophil CD11b/CD18 levels were significantly lower for all study groups versus control at T2, for both coated groups at T3 and only for closed+coated group at T4 (p < .05). Postoperative hemorrhage (mL) was 510 ± 40 in closed+coated and 536 ± 40 in open+coated groups (control: 784 ± 48, p ≤ .05). No significant differences in thrombin-antithrombin complex and free plasma hemoglobin were observed. Desorbed protein amount on ECC (mg/dL) was 1.7 ± .01 in closed+coated, 2.01 ± .01 in open+coated, and 3.3 ± .015 in control groups (p ≤ .05). Use of a

  1. Hyaluronan based heparin free coated open and closed extracorporeal circuits for high risk coronary revascularization.

    PubMed

    Gunaydin, Serdar; Ucar, Halil Ibrahim; Serter, Tanzer; McCusker, Kevin; Ozcelik, Gokhan; Salman, Nevriye; Yorgancioglu, Ali Cem

    2010-12-01

    This prospective randomized study compares the inflammatory response and fibrinolytic activation of fully coated/uncoated and open/closed extracorporeal circuits (ECC) in high risk patients. Over a 2-month period, 48 patients with EuroSCOREs 6 or greater undergoing coronary revascularization were prospectively randomized to one of the four perfusion protocols: Group 1: Closed and totally hyaluronan based heparin free coated (Vision HFO-GBS-HF, Gish Biomedical, Rancho Santa Margarita, CA) ECC with a soft-shell coated venous reservoir (SVR11S2-HFC, Gish Biomedical) and a hard-shell cardiotomy (CAPVRF44, Gish Biomedical) (n = 12); Group 2: Closed and totally uncoated identical ECC with soft-shell uncoated venous reservoir and a hard-shell cardiotomy (n = 12); Group 3: Open, totally hyaluronan based heparin free coated ECC (n = 12); and Group 4: Control-open, uncoated ECC (n = 12). Blood samples were collected at T1: Baseline; T2: 15 minutes after cardiopulmonary bypass (CPB) initiation; T3: before cessation of CPB; T4: 15 minutes after protamine reversal, and T5: in the intensive care unit. Serum IL-6 levels were significantly lower at T2 in all study groups, at T3 for coated groups, and T4 for closed+coated group (p < .05 versus control). Creatine kinase M-band (MB) levels in coronary sinus blood demonstrated well preserved myocardium after CPB in both coated groups versus Control (p < .05). Neutrophil CD11b/CD18 levels were significantly lower for all study groups versus control at T2, for both coated groups at T3 and only for closed + coated group at T4 (p < .05). Postoperative hemorrhage (mL) was 510 +/- 40 in closed + coated and 536 +/- 40 in open + coated groups (control: 784 +/- 48, p < .05). No significant differences in thrombin-antithrombin complex and free plasma hemoglobin were observed. Desorbed protein amount on ECC (mg/dL) was 1.7 +/- .01 in closed+coated, 2.01 +/- .01 in open+coated, and 3.3 +/- .015 in control groups (p < or = .05). Use of a closed

  2. Exploring Differences between Self-Regulated Learning Strategies of High and Low Achievers in Open Distance Learning

    ERIC Educational Resources Information Center

    Geduld, Bernadette

    2016-01-01

    Open distance students differ in their preparedness for higher education studies. Students who are less self-regulated risk failure and drop out in the challenging milieu of open distance learning. In this study, the differences between the application of self-regulated learning strategies by low and high achievers were explored. A multi-method…

  3. Capillary surfaces in a wedge: Differing contact angles

    NASA Technical Reports Server (NTRS)

    Concus, Paul; Finn, Robert

    1994-01-01

    The possible zero-gravity equilibrium configurations of capillary surfaces u(x, y) in cylindrical containers whose sections are (wedge) domains with corners are investigated mathematically, for the case in which the contact angles on the two sides of the wedge may differ. In such a situation the behavior can depart in significant qualitative ways from that for which the contact angles on the two sides are the same. Conditions are described under which such qualitative changes must occur. Numerically computed surfaces are depicted to indicate the behavior.

  4. Development of high-gradient and open-gradient magnetic separation

    SciTech Connect

    Hise, E C

    1981-01-01

    This paper was prepared: to review the accomplishments in both high-gradient magnetic separation (HGMS) and open-gradient magnetic separation (OGMS) by the Oak Ridge National Laboratory (ORNL) group during the past three years; to show, through the medium of motion pictures, the operation of the various separation methods and devices used and developed; to show qualitative results of the separation performed; and to make available, to those interested, detailed reports of the experimental procedures and the resulting data. The qualitative separation of pyritic sulfur and ash forming minerals from fine coal by high gradient magnetic separation has been demonstrated at feed rates up to one ton per hour, and in a machine that is commercially produced in sizes for feed rates up to several hundred tons per hour. The quantitative separation of pyritic sulfur and ash forming minerals from fine coal by free fall open gradient magnetic separation has been demonstrated at a laboratory scale and at 300 kg per hour in a solenoidal magnet configuration. A magnet modeling analysis has shown that an optimum magnet can be designed with practical physical constraints which can generate separating forces two to three times those of the existing solenoidal configuration and with a large processing capacity. The analytical predictions of the behavior of particles traversing these separating forces have been experimentally confirmed within 15% in existing magnets.

  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. Anatexis of accretionary wedge, Pacific-type magmatism, and formation of vertically stratified continental crust in the Altai Orogenic Belt

    NASA Astrophysics Data System (ADS)

    Jiang, Y. D.; Schulmann, K.; Sun, M.; Å típská, P.; Guy, A.; Janoušek, V.; Lexa, O.; Yuan, C.

    2016-12-01

    Granitoid magmatism and its role in differentiation and stabilization of the Paleozoic accretionary wedge in the Chinese Altai are evaluated in this study. Voluminous Silurian-Devonian granitoids intruded a greywacke-dominated Ordovician sedimentary succession (the Habahe Group) of the accretionary wedge. The close temporal and spatial relationship between the regional anatexis and the formation of granitoids, as well as their geochemical similarities including rather unevolved Nd isotopic signatures and the strong enrichment of large-ion lithophile elements relative to many of the high field strength elements, may indicate that the granitoids are product of partial melting of the accretionary wedge rocks. Whole-rock geochemistry and pseudosection modeling show that regional anatexis of fertile sediments could have produced a large amount of melts compositionally similar to the granitoids. Such process could have left a high-density garnet- and/or garnet-pyroxene granulite residue in the deep crust, which can be the major reason for the gravity high over the Chinese Altai. Our results show that melting and crustal differentiation can transform accretionary wedge sediments into vertically stratified and stable continental crust. This may be a key mechanism contributing to the peripheral continental growth worldwide.

  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. 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.

  9. High-throughput syntheses of iron phosphite open frameworks in ionic liquids

    NASA Astrophysics Data System (ADS)

    Wang, Zhixiu; Mu, Ying; Wang, Yilin; Bing, Qiming; Su, Tan; Liu, Jingyao

    2017-02-01

    Three open-framework iron phosphites: Feп5(NH4)2(HPO3)6 (1), Feп2Fe♯(NH4)(HPO3)4 (2) and Fe♯2(HPO3)3 (3) have been synthesized under ionothermal conditions. How the different synthesis parameters, such as the gel concentrations, synthetic times, reaction temperatures and solvents affect the products have been monitored by using high-throughput approaches. Within each type of experiment, relevant products have been investigated. The optimal reaction conditions are obtained from a series of experiments by high-throughput approaches. All the structures are determined by single-crystal X-ray diffraction analysis and further characterized by PXRD, TGA and FTIR analyses. Magnetic study reveals that those three compounds show interesting magnetic behavior at low temperature.

  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. Thermocleavable materials for polymer solar cells with high open circuit voltage-a comparative study.

    PubMed

    Tromholt, Thomas; Gevorgyan, Suren A; Jørgensen, Mikkel; Krebs, Frederik C; Sylvester-Hvid, Kristian O

    2009-12-01

    The search for polymer solar cells giving a high open circuit voltage was conducted through a comparative study of four types of bulk-heterojunction solar cells employing different photoactive layers. As electron donors the thermo-cleavable polymer poly-(3-(2-methylhexyloxycarbonyl)dithiophene) (P3MHOCT) and unsubstituted polythiophene (PT) were used, the latter of which results from thermo cleaving the former at 310 degrees C. As reference, P3HT solar cells were built in parallel. As electron acceptors, either PCBM or bis-[60]PCBM were used. In excess of 300 solar cells were produced under as identical conditions as possible, varying only the material combination of the photo active layer. It was observed that on replacing PCBM with bis[60]PCBM, the open circuit voltage on average increased by 100 mV for P3MHOCT and 200 mV for PT solar cells. Open circuit voltages approaching 1 V were observed for the PT:bis[60]PCBM solar cells and a maximum conversion efficiency of 1.3% was obtained for solar cells with P3MHOCT:PCBM as the photoactive material. For the reference solar cells maximum efficiencies of 2.1 and 2.4% were achieved for P3HT:PCBM and P3HT:bis[60]PCBM, respectively. Despite special measures taken in terms of substrate design and device processing, a substantial spread in the photovoltaic properties was generally observed. This spread could not be correlated with the optical properties of the solar cells, the thickness of the photo active layer or the electrode deposition conditions of the aluminum top electrode.

  12. Contemporaneous comparison of open vs minimally-invasive radical prostatectomy for high-risk prostate cancer

    PubMed Central

    Pierorazio, Phillip M.; Mullins, Jeffrey K.; Eifler, John B.; Voth, Kipp; Hyams, Elias S.; Han, Misop; Pavlovich, Christian P.; Bivalacqua, Trinity J.; Partin, Alan W.; Allaf, Mohamad E.; Schaeffer, Edward M.

    2014-01-01

    Objectives • To analyze pathological and short-term oncological outcomes in men undergoing open and minimally-invasive radical prostatectomy (MIRP) for high-risk prostate cancer (HRPC; prostate-specific antigen level [PSA] >20 ng/mL, ≥cT2c, Gleason score 8–10) in a contemporaneous series. Patients and Methods • In total, 913 patients with HRPC were identified in the Johns Hopkins Radical Prostatectomy Database subsequent to the inception of MIRP at this institution (2002–2011) • Of these, 743 (81.4%) underwent open radical retropubic prostatectomy (ORRP), 105 (11.5%) underwent robot-assisted laparoscopic radical prostatectomy (RALRP) and 65 (7.1%) underwent laparoscopic radical prostatectomy (LRP) for HRPC. • Appropriate comparative tests were used to evaluate patient and prostate cancer characteristics. • Proportional hazards regression models were used to predict biochemical recurrence. Results • Age, race, body mass index, preoperative PSA level, clinical stage, number of positive cores and Gleason score at final pathology were similar between ORRP and MIRP. • On average, men undergoing MIRP had smaller prostates and more organ-confined (pT2) disease (P = 0.02). • The number of surgeons and surgeon experience were greatest for the ORRP cohort. • Overall surgical margin rate was 29.4%, 34.3% and 27.7% (P = 0.52) and 1.9%, 2.9% and 6.2% (P = 0.39) for pT2 disease in men undergoing ORRP, RALRP and LRP, respectively. • Biochemical recurrence-free survival among ORRP, RALRP and LRP was 56.3%, 67.8% and 41.1%, respectively, at 3 years (P = 0.6) and the approach employed did not predict biochemical recurrence in regression models. Conclusions • At an experienced centre, MIRP is comparable to open radical prostatectomy for HRPC with respect to surgical margin status and biochemical recurrence. PMID:23356390

  13. A study on high subsonic airfoil flows in relatively high Reynolds number by using OpenFOAM

    NASA Astrophysics Data System (ADS)

    Nakao, Shinichiro; Kashitani, Masashi; Miyaguni, Takeshi; Yamaguchi, Yutaka

    2014-04-01

    In the present study, numerical calculations of the flow-field around the airfoil model are performed by using the OpenFOAM in high subsonic flows. The airfoil model is NACA 64A010. The maximum thickness is 10 % of the chord length. The SonicFOAM and the RhoCentralFOAM are selected as the solver in high subsonic flows. The grid point is 158,000 and the Mach numbers are 0.277 and 0.569 respectively. The CFD data are compared with the experimental data performed by the cryogenic wind tunnel in the past. The results are as follows. The numerical results of the pressure coefficient distribution on the model surface calculated by the SonicFOAM solver showed good agreement with the experimental data measured by the cryogenic wind tunnel. And the data calculated by the SonicFOAM have the capability for the quantitative comparison of the experimental data at low angle of attack.

  14. 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

  15. 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.

  16. Molecular imprint polymers as highly selective stationary phases for open tubular liquid chromatography and capillary electrochromatography.

    PubMed

    Tan, Z J; Remcho, V T

    1998-09-01

    Chiral separations employing molecular imprint polymer (MIP) stationary phases in both open tubular liquid chromatography (OT-LC) and capillary electrochromatography (OT-CEC) are demonstrated. MIPs are highly crosslinked polymers containing spatial and functionality memory of template molecules which provide a higher degree of selectivity when used as stationary phases for chromatographic separations. Thin films of molecular imprinted polymers bonded to the inner walls of 25 microm ID fused-silica capillaries were prepared using an in situ polymerization technique developed in our laboratory that allows the use of conventional fused-silica capillaries with polyimide outer coatings. The success rate in preparing such open tubular columns was about 70%. Methacrylic acid and 2-vinyl pyridine were chosen as functional monomers, and either ethylene dimethacrylate or trimethylol propane trimethacrylate was used as the crosslinker. Toluene was employed as the porogen. Effects of polymerization conditions on column preparation and chromatographic performance were studied. Enantiomeric separations of D- and L-dansyl phenylalanines were achieved in both OT-LC and OT-CEC modes with good selectivity and efficiencies. Both types of separations may be performed on the same column using a single commercial instrument.

  17. 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.

  18. Population Connectivity Shifts at High Frequency within an Open-Coast Marine Protected Area Network

    PubMed Central

    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

  19. 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.

  20. Acoustic or Electromagnetic Scattering from the Penetrable Wedge

    DTIC Science & Technology

    1993-02-28

    difference equation to be solved in the transform variable. A special inhomogeneous surface impedance yields purely algebraic equations for the... lineal density is located at the source coordinates (r’, 0’) of Fig. 1. The permittivity of the wedge of angle 2a is f 2 , which is surrounded by a

  1. 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.

  2. Dynamics of Sub-Micron Bubbles Growing in a Wedge in the Low Capillary Number Regime

    NASA Astrophysics Data System (ADS)

    Norton, Michael; Park, Jeung; Kodambaka, Suneel; Ross, Frances; Bau, Haim

    2014-11-01

    Using a hermetically-sealed liquid cell, we observed the growth and migration of bubbles (tens to hundreds of nanometers in diameter) with a transmission electron microscope. The internal pressure of the liquid caused the thin silicon nitride membranes that comprise the cell's observation windows to bow outward, creating spatial gradients in the liquid cell's height. As a result, growing bubbles migrated in the direction of increasing cell height. To better understand the migration dynamics, we developed a simple, two-dimensional model to predict the translational velocity of a bubble that makes contact with both wedge surfaces as a function of the bubble growth rate and wedge opening angle. The model is valid in the asymptotic limit of zero capillary number and relies on a phenomenological relationship between the contact line velocity and the dynamic contact angle. The theoretical predictions are compared with experimental observations. MN was supported, in part, by the Nano/Bio Interface Center through the National Science Foundation NSEC DMR08-32802. HHB and FR were supported, in part, by Grants 1129722 and 1066573 from the National Science Foundation.

  3. Wedges, cones, cosmic strings and their vacuum energy

    NASA Astrophysics Data System (ADS)

    Fulling, S. A.; Trendafilova, C. S.; Truong, P. N.; Wagner, J.

    2012-09-01

    One of J Stuart Dowker’s most significant achievements has been to observe that the theory of diffraction by wedges developed a century ago by Sommerfeld and others provided the key to solving two problems of great interest in general-relativistic quantum field theory during the last quarter of the 20th century: the vacuum energy associated with an infinitely thin, straight cosmic string, and (after an interchange of time with a space coordinate) the apparent vacuum energy of empty space as viewed by an accelerating observer. In a sense the string problem is more elementary than the wedge, since Sommerfeld’s technique was to relate the wedge problem to that of a conical manifold by the method of images. Indeed, Minkowski space, as well as all cone and wedge problems, are related by images to an infinitely sheeted master manifold, which we call Dowker space. We review the research in this area and exhibit in detail the vacuum expectation values of the energy density and pressure of a scalar field in Dowker space and the cone and wedge spaces that result from it. We point out that the (vanishing) vacuum energy of Minkowski space results, from the point of view of Dowker space, from the quantization of angular modes, in precisely the way that the Casimir energy of a toroidal closed universe results from the quantization of Fourier modes; we hope that this understanding dispels any lingering doubts about the reality of cosmological vacuum energy. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker’s 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’.

  4. Open- and Closed-Loop Dynamics of the High-Efficiency Antenna Subreflector

    NASA Astrophysics Data System (ADS)

    Kuczenski, M. B.; Gawronski, W.

    2000-07-01

    The subreflector of the high-efficiency (HEF) antenna moves in three axes, while the subreflector controller supervises these movements. The precision of subreflector response to the controller commands is essential to maintaining the antenna-pointing precision. This article presents the development of the control system model of the HEF antenna subreflector. It includes the dynamics of the open-loop (or rate-loop) system, the development of the controller, and the simulations of the closed-loop performance. The analysis shows that the closed-loop dynamics, such as settling time, overshoot, and bandwidth, are comparable to the antenna closed-loop dynamics; thus, they are able to meet the pointing requirements.

  5. High open circuit voltages of solar cells based on quantum dot and dye hybrid-sensitization

    SciTech Connect

    Zhao, Yujie; Zhao, Wanyu; Chen, Jingkuo; Li, Huayang; Fu, Wuyou E-mail: fuwy56@163.com; Sun, Guang; Cao, Jianliang; Zhang, Zhanying; Bala, Hari E-mail: fuwy56@163.com

    2014-01-06

    A type of solar cell based on quantum dot (QD) and dye hybrid-sensitized mesoporous TiO{sub 2} film electrode was designed and reported. The electrode was consisted of a TiO{sub 2} nanoparticle (NP) thin film layer sensitized with CdS quantum dot (QD) and an amorphous TiO{sub 2} coated TiO{sub 2} NP thin film layer that sensitized with C106 dye. The amorphous TiO{sub 2} layer was obtained by TiCl{sub 4} post-treatment to improve the properties of solar cells. Research showed that the solar cells fabricated with as-prepared hybrid-sensitized electrode exhibited excellent photovoltaic performances and a fairly high open circuit voltage of 796 mV was achieved.

  6. Development of highly open polyhedral networks from vitreous carbon for orthopaedic applications

    NASA Astrophysics Data System (ADS)

    Güiza-Argüello, V.; Bayona-Becerra, M.; Cruz-Orellana, S.; Córdoba-Tuta, E.

    2017-01-01

    Highly open polyhedral networks were fabricated using an economical and environmentally friendly template route. Recycled cellulose foams were impregnated with a sucrose resin and then pyrolyzed in order to produce reticulated vitreous carbon foams with morphological features that closely resemble trabecular bone. Also, cell sizes ~1mm were achieved, a trait that will allow the mechanical reinforcement of such scaffolds using a biomaterial coating without compromising the pore size that favors osteoblast cell infiltration and growth (200-500µm). Moreover, initial studies showed that carbonization conditions have an effect on the mechanical properties of the synthesized foams and, therefore, such process parameters could be further evaluated towards the enhancement of the mechanical resistance of the scaffolds. The materials developed here are visualized as the porous component of a synthetic bone graft with features that could help overcome the current limitations associated with the medical treatments used for bone defect repair.

  7. 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

  8. Realizing the increased potential of an open-system high-definition digital projector design

    NASA Astrophysics Data System (ADS)

    Daniels, Reginald

    1999-05-01

    Modern video projectors are becoming more compact and capable. Various display technologies are very competitive and are delivering higher performance and more compact projectors to market at an ever quickening pace. However the end users are often left with the daunting task of integrating the 'off the self projectors' into a previously existing system. As the projectors become more digitally enhanced, there will be a series of designs, and the digital projector technology matures. The design solutions will be restricted by the state of the art at the time of manufacturing. In order to allow the most growth and performance for a given price, many design decisions will be made and revisited over a period of years or decades. A modular open digital system design concept is indeed a major challenge of the future high definition digital displays for al applications.

  9. Open hole packer for high pressure service in a five hundred degree fahrenheit precambrian wellbore

    SciTech Connect

    Dreesen, D.S.; Miller, J.R.; Halbardier, F.A.; Nicholson, R.W.

    1985-01-01

    Massive hydraulic fracturing (MHF) from a lower wellbore (EE-2) created a large man-made reservoir which did not intersect the upper well (EE-3). To create a heat extraction flow loop, the upper well was sidetracked and redrilled (EE-3A) down into a microseismic cloud around EE-2 mapped during the MHF. The potential to intersect numerous fracture zones in the redrilled bore was apparent from seismicity. To economically and effectively isolate and test these microseismic zones required that a functional open hole packer be developed. The packer would be exposed to soak temperatures as high as 500/sup 0/F (260/sup 0/C) with cool down to 100/sup 0/F (40/sup 0/C) at differential pressures exceeding 5000 psi (35 Mpa). A functional packer has been designed, manufactured, and successfully used for the creation of a hot dry rock (HDR) reservoir. 5 figs., 1 tab.

  10. 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.

  11. 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.

  12. 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.

  13. Phylogenetic analysis of bacteria preserved in a permafrost ice wedge for 25,000 years.

    PubMed

    Katayama, Taiki; Tanaka, Michiko; Moriizumi, Jun; Nakamura, Toshio; Brouchkov, Anatoli; Douglas, Thomas A; Fukuda, Masami; Tomita, Fusao; Asano, Kozo

    2007-04-01

    Phylogenetic analysis of bacteria preserved within an ice wedge from the Fox permafrost tunnel was undertaken by cultivation and molecular techniques. The radiocarbon age of the ice wedge was determined. Our results suggest that the bacteria in the ice wedge adapted to the frozen conditions have survived for 25,000 years.

  14. P-Wave to Rayleigh-wave conversion coefficients for wedge corners; model experiments

    USGS Publications Warehouse

    Gangi, A.F.; Wesson, R.L.

    1978-01-01

    An analytic solution is not available for the diffraction of elastic waves by wedges; however, numerical solutions of finite-difference type are available for selected wedge angles. The P- to Rayleigh-wave conversion coefficients at wedge tips have been measured on two-dimensional seismic models for stress-free wedges with wedge angles, ??0, of 10, 30, 60, 90 and 120??. The conversion coefficients show two broad peaks and a minimum as a function of the angle between the wedge face and the direction of the incident P-wave. The minimum occurs for the P wave incident parallel to the wedge face and one maximum is near an incidence angle of 90?? to the wedge face. The amplitude of this maximum, relative to the other, decreases as the wedge angle increases. The asymmetry of the conversion coefficients, CPR(??; ??0), relative to parallel incidence (?? = 0) increases as the wedge angle increases. The locations of the maxima and the minimum as well as the asymmetry can be explained qualitatively. The conversion coefficients are measured with an accuracy of ??5% in those regions where there are no interfering waves. A comparison of the data for the 10?? wedge with the theoretical results for a half plane (0?? wedge) shows good correlation. ?? 1978.

  15. Differential Expression and Functional Analysis of High-Throughput -Omics Data Using Open Source Tools.

    PubMed

    Kebschull, Moritz; Fittler, Melanie Julia; Demmer, Ryan T; Papapanou, Panos N

    2017-01-01

    Today, -omics analyses, including the systematic cataloging of messenger RNA and microRNA sequences or DNA methylation patterns in a cell population, organ, or tissue sample, allow for an unbiased, comprehensive genome-level analysis of complex diseases, offering a large advantage over earlier "candidate" gene or pathway analyses. A primary goal in the analysis of these high-throughput assays is the detection of those features among several thousand that differ between different groups of samples. In the context of oral biology, our group has successfully utilized -omics technology to identify key molecules and pathways in different diagnostic entities of periodontal disease.A major issue when inferring biological information from high-throughput -omics studies is the fact that the sheer volume of high-dimensional data generated by contemporary technology is not appropriately analyzed using common statistical methods employed in the biomedical sciences.In this chapter, we outline a robust and well-accepted bioinformatics workflow for the initial analysis of -omics data generated using microarrays or next-generation sequencing technology using open-source tools. Starting with quality control measures and necessary preprocessing steps for data originating from different -omics technologies, we next outline a differential expression analysis pipeline that can be used for data from both microarray and sequencing experiments, and offers the possibility to account for random or fixed effects. Finally, we present an overview of the possibilities for a functional analysis of the obtained data.

  16. Building highly available control system applications with Advanced Telecom Computing Architecture and open standards

    NASA Astrophysics Data System (ADS)

    Kazakov, Artem; Furukawa, Kazuro

    2010-11-01

    Requirements for modern and future control systems for large projects like International Linear Collider demand high availability for control system components. Recently telecom industry came up with a great open hardware specification - Advanced Telecom Computing Architecture (ATCA). This specification is aimed for better reliability, availability and serviceability. Since its first market appearance in 2004, ATCA platform has shown tremendous growth and proved to be stable and well represented by a number of vendors. ATCA is an industry standard for highly available systems. On the other hand Service Availability Forum, a consortium of leading communications and computing companies, describes interaction between hardware and software. SAF defines a set of specifications such as Hardware Platform Interface, Application Interface Specification. SAF specifications provide extensive description of highly available systems, services and their interfaces. Originally aimed for telecom applications, these specifications can be used for accelerator controls software as well. This study describes benefits of using these specifications and their possible adoption to accelerator control systems. It is demonstrated how EPICS Redundant IOC was extended using Hardware Platform Interface specification, which made it possible to utilize benefits of the ATCA platform.

  17. High-throughput metagenomic technologies for complex microbial community analysis. Open and closed formats

    DOE PAGES

    Zhou, Jizhong; He, Zhili; Yang, Yunfeng; ...

    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. Recent movements along the Main Boundary Thrust of the Himalayas: Normal faulting in an over-critical thrust wedge?

    NASA Astrophysics Data System (ADS)

    Mugnier, Jean-Louis; Huyghe, Pascale; Chalaron, Edouard; Mascle, Georges

    1994-11-01

    The Main Boundary Thrust (MBT) is one of the major Himalayan thrusts occurring during the Cainozoic, and it is presently incorporated within the Himalayan thrust wedge (Lesser and Outer Himalayas) displaced above the Indian lithosphere. Nonetheless the MBT shows recent normal displacement along most of its length. We suggest that the orientation of the major principal stress within the Himalayan thrust wedge deviates significantly from the horizontal and when this deviation exceeds the dip of the vectors normal to back-tilted thrusts, the normal component of displacement may act along these faults. Steep north-dipping segments of the MBT therefore show a normal component of displacement if a geometrical definition is used, but they are faults in a compressional regime where the major principal stress axis has deviated from the horizontal. Micro-structural data recorded along the Surkhet-Ghorahi segment of the MBT are consistent with a strong deviation of the state of stress. The presence of such peculiar normal faulting along the MBT is used to calibrate the mechanical characteristics of the belt considered as a Coulomb wedge. The following characteristics are suggested: (a) very poor strength contrast between basal decollement and rocks in the wedge body, (b) a high pore fluid pressure ratio (probably close to 0.8-0.9) and a higher fluid pressure ratio (close to 1.0) along the active normal faults if a high internal friction angle (close to the Byerlee value) is considered. The strong deviation in principal stress direction may have recently increased, due to a taper of the Himalayan wedge exceeding the stability boundary and may be controlled by erosion and isostatic uplift rebound of the Himalayan range.

  19. 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.

  20. Gap formation processes in a high-density plasma opening switch

    NASA Astrophysics Data System (ADS)

    Grossmann, J. M.; Swanekamp, S. B.; Ottinger, P. F.; Commisso, R. J.; Hinshelwood, D. D.; Weber, B. V.

    1995-01-01

    A gap opening process in plasma opening switches (POS) is examined with the aid of numerical simulations. In these simulations, a high density (ne=1014-5×1015 cm-3) uniform plasma initially bridges a small section of the coaxial transmission line of an inductive energy storage generator. A short section of vacuum transmission line connects the POS to a short circuit load. The results presented here extend previous simulations in the ne=1012-1013 cm-3 density regime. The simulations show that a two-dimensional (2-D) sheath forms in the plasma near a cathode. This sheath is positively charged, and electrostatic sheath potentials that are large compared to the anode-cathode voltage develop. Initially, the 2-D sheath is located at the generator edge of the plasma. As ions are accelerated out of the sheath, it retains its original 2-D structure, but migrates axially toward the load creating a magnetically insulated gap in its wake. When the sheath reaches the load edge of the POS, the POS stops conducting current and the load current increases rapidly. At the end of the conduction phase a gap exists in the POS whose size is determined by the radial dimensions of the 2-D sheath. Simulations at various plasma densities and current levels show that the radial size of the gap scales roughly as B/ne, where B is the magnetic field. The results of this work are discussed in the context of long-conduction-time POS physics, but exhibit the same physical gap formation mechanisms as earlier lower density simulations more relevant to short-conduction-time POS.

  1. Outlook for the use of microsecond plasma opening switches to generate high-power nanosecond current pulses

    NASA Astrophysics Data System (ADS)

    Dolgachev, G. I.; Maslennikov, D. D.; Ushakov, A. G.

    2006-12-01

    An analysis is made of the current break process in microsecond plasma opening switches and their possible application in high-current generators. Necessary conditions are determined for generating megavolt pulses in the erosion mode of a plasma opening switch with the gap insulated by an external magnetic field. Under these conditions, efficient sharpening of high-power submegampere current pulses can be achieved. The possibility of using plasma opening switches operating at voltages of 5 6 MV to generate X-ray and gamma emission is discussed. The main operating and design parameters of a six-module plasma opening switch with a current pulse amplitude of 3.7 MA and voltage of 4 6 MV for use in the MOL generator, which is the prototype of one of the 24 modules of the projected Baikal multimegajoule generator, are estimated by using the available scalings.

  2. 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

  3. 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.

  4. 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%.

  5. Generation of high-current electron beam in a wide-aperture open discharge

    NASA Astrophysics Data System (ADS)

    Bokhan, P. A.; Zakrevsky, Dm. E.; Gugin, P. P.

    2011-10-01

    In the present study, it was examined generation of nanosecond-duration electron-beam (EB) pulses by a wide-aperture open discharge burning in helium or in a mixture of helium with nitrogen and water vapor. In the experiments, a discharge cell with coaxial electrode geometry, permitting radial injection of the electron beam into operating lasing medium, was used, with the cathode having radius 2.5 cm and length 12 cm. It was shown possible to achieve an efficient generation of a high-intensity electron beam (EB pulse power ˜250 MW and EB pulse energy up to 4 J) in the kiloampere range of discharge currents (up to 26 kA at ˜12 kV discharge voltage). The current-voltage characteristics of the discharge proved to be independent of the working-gas pressure. The existence of an unstable dynamic state of EB, conditioned by the presence of an uncompensated space charge accumulated in the discharge cell due to the exponential growth of the current in time during discharge initiation and the hyperbolic growth of current density in the direction towards the tube axis, was revealed. The obtained pulsed electron beam was used to excite the self-terminated laser on He 21P10-21S0 transition. The oscillations developing in the discharge cell at high discharge currents put limit to the pumping energy and emissive power of the laser excited with the radially converging electron beam.

  6. 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.

  7. 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

  8. Analysis of a wedge prism to perform small-angle beam deviation

    NASA Astrophysics Data System (ADS)

    Senderakova, Dagmar; Strba, Anton

    2003-07-01

    The contribution is to present both the theoretical and experimental analysis of a wedge prism, which allows us to perform very small angle deviation of a passing beam in a simply way. No high precise steering element is necessary. The results of the theoretical analysis, i.e. the dependence of the propagation vector on the angle of incidence had been verified experimentally, using both Mach-Zehnder interferometer and a holographic grating. The results obtained have proved the advantage of the method proposed, which may be of great importance anywhere if small-angle deviation of propagation wave vector is needed.

  9. Origin of the high open circuit voltage in planar heterojunction perovskite solar cells: Role of the reduced bimolecular recombination

    NASA Astrophysics Data System (ADS)

    Yang, Wenchao; Yao, Yao; Wu, Chang-Qin

    2015-03-01

    The high open circuit voltage is an attractive feature for the currently popular organic-inorganic hybrid perovskite solar cells. In this paper, by employing the macroscopic device model simulation, we investigate its origin for the planar heterojunction perovskite solar cells. Based on the calculated current density-voltage characteristics, it is revealed that compared to the excitonic solar cells, the fast thermal-activated exciton dissociation in the bulk due to the small exciton binding energy may improve the short circuit current and the fill factor, but its beneficial role on the open circuit voltage is marginal. The most significant contribution for the open circuit voltage comes from the reduced bimolecular recombination. In the perovskites, with the recombination prefactor many orders of magnitude smaller than that based on the Langevin's theory, the internal charge density level is significantly enhanced and the density gradient is removed, leading to the high quasi-Fermi level splitting and thus the small open circuit voltage loss. For the nonradiative recombination pathway due to the deep trap states, it may induce significant loss of open circuit voltage as the trap density is high, while for the moderately low density its effect on the open circuit voltage is small and negligible.

  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. 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.

  12. Developing Open Source Software To Advance High End Computing. Report to the President.

    ERIC Educational Resources Information Center

    National Coordination Office for Information Technology Research and Development, Arlington, VA.

    This is part of a series of reports to the President and Congress developed by the President's Information Technology Advisory Committee (PITAC) on key contemporary issues in information technology. This report defines open source software, explains PITAC's interest in this model, describes the process used to investigate issues in open source…

  13. Shock wave reflection over convex and concave wedge

    NASA Astrophysics Data System (ADS)

    Kitade, M.; Kosugi, T.; Yada, K.; Takayama, Kazuyoshi

    2001-04-01

    It is well known that the transition criterion nearly agrees with the detachment criterion in the case of strong shocks, two-dimensional, and pseudosteady flow. However, when the shock wave diffracts over a wedge whose angle is below the detachment criterion, that is, in the domain of Mach reflection, precursory regular reflection (PRR) appears near the leading edge and as the shock wave propagates, the PRR is swept away by the overtaking corner signal (cs) that forces the transition to Mach reflection. It is clear that viscosity and thermal conductivity influences transition and the triple point trajectory. On the other hand, the reflection over concave and convex wedges is truly unsteady flow, and the effect of viscosity and thermal conductivity on transition and triple point trajectory has not been reported. This paper describes that influence of viscosity over convex and concave corners investigated both experiments and numerical simulations.

  14. MHD Casson nanofluid flow past a wedge with Newtonian heating

    NASA Astrophysics Data System (ADS)

    Ahmad, Kartini; Hanouf, Zahir; Ishak, Anuar

    2017-02-01

    The problem of steady Casson nanofluid flow past a wedge is studied in this paper. The presence of magnetic field along with Newtonian heating at the surface is considered. The governing partial differential equations are first transformed into a set of nonlinear ordinary differential equations by similarity transformations, before being solved numerically using the Keller-box method. The effects of the wedge angle Ω from 0° (horizontal plate) to 180° (vertical plate) as well as of as the magnetic parameter M on the non-Newtonian fluid flow and heat transfer characteristics are investigated. It is found that the surface temperature is slightly higher for the flow over a horizontal plate compared to that over a vertical plate. It is also found that the magnetic field decreases the surface temperature but increases the skin friction. The flow of a Newtonian fluid is found to give higher skin friction as compared to that of Casson fluid.

  15. Nickel oxide film with open macropores fabricated by surfactant-assisted anodic deposition for high capacitance supercapacitors.

    PubMed

    Wu, Mao-Sung; Wang, Min-Jyle

    2010-10-07

    Nickel oxide film with open macropores prepared by anodic deposition in the presence of surfactant shows a very high capacitance of 1110 F g(-1) at a scan rate of 10 mV s(-1), and the capacitance value reduces to 950 F g(-1) at a high scan rate of 200 mV s(-1).

  16. 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

  17. Regional Patterns of Ice-Wedge Degradation Across Northern Alaska: What Does Asynchronous Timing of Onset Tell Us Regarding Triggering Mechanisms, Thresholds, and Impacts?

    NASA Astrophysics Data System (ADS)

    Frost, G. V., Jr.; Macander, M. J.; Liljedahl, A. K.; Walker, D. A.

    2015-12-01

    Ice-wedge polygons are conspicuous and widespread in arctic landscapes, creating complex microtopography and strong, meter-scale contrasts in hydrology, soil, vegetation, and ground ice conditions. Thaw of the upper portion of ice-wedges results in ground subsidence (thermokarst), plant mortality and the formation of small, flooded pits along the polygon margins. Secondary impacts, such as changes in flowpaths, spatially-variable flooding and drainage of polygon centers, and thermal erosion of permafrost, extend well beyond the thermokarst pits themselves. We delineated small waterbodies in historical airphotos and modern high-resolution satellite imagery and made ground observations across a network of 45 km2 study areas spanning the western and central regions of Alaska's North Slope. The imagery archive covers three epochs: 1948-1955, 1979-1985, and 2009-2012. Our analysis focused on residual upland surfaces dominated by Holocene-aged ice wedges, where surface water is mainly restricted to degraded ice-wedges. Total extent of flooded pits increased at most landscapes since circa 1980 (range -27 - +135%; median +10.6%). An intriguing regional pattern was evident: degradation of Holocene ice-wedges was already well underway by 1950 across much of the western North Slope, but degradation initiated much more recently on eolian sand and silt (yedoma) deposits prevalent to the east. Our results indicate that recent degradation of Holocene ice wedges across northern Alaska cannot be explained by late-20th century warmth alone. Possible mechanisms for earlier onset of degradation on the western North Slope include differences in recent climate history, snow regime, and thermal and physical properties of surficial materials. These findings provide context for interpreting and predicting ice-wedge thermokarst processes, thresholds, and impacts in Alaska and elsewhere in the circumpolar arctic.

  18. Across-arc variations of isotope and trace element compositions from Quaternary basaltic volcanic rocks in northeastern Japan: Implications for interaction between subducted oceanic slab and mantle wedge

    NASA Astrophysics Data System (ADS)

    Shibata, Tomoyuki; Nakamura, Eizo

    1997-04-01

    Isotopic compositions of Pb, Sr, and Nd and concentrations of trace elements were determined for Quaternary island arc basaltic rocks from northeastern Japan. Sr and Pb isotopic ratios decrease, and Nd isotopic ratios increase from the volcanic front toward the back arc. The isotopic compositions nearest the back arc side are nearly identical to those of mid-ocean ridge basalt (MORB). The high field strength elements and heavy rare earth elements show homogeneous and MORB-like characteristics. These observations indicate that the mantle wedge beneath northeastern Japan originally had a MORB-type mantle composition that was homogeneous across the arc. Pb isotope compositions show a mixing relationship between mantle wedge and oceanic sediments reflecting the introduction of subduction component into the mantle wedge, Across-arc isotopic variations were caused by interaction between MORB-type mantle wedge and the subducting slab, and the amount of subduction component correlates with the depth to the slab. The isotopic compositions of subduction component are expressed by bulk mixing of 15 wt % of oceanic sediment and 85 wt % of altered MORB. Inversion analyses of isotopic compositions using two-component mixing relationships show that the Sr/Nd and Pb/Nd ratios in subduction component decrease with increasing depth to the slab, while the Sr/Pb ratio is nearly constant. These changes can be explained only by a preferential discharge of the elements into the wedge mantle associated with continuous dehydration of the subducting slab. The present study further demonstrates that a very wide range of isotopic and elemental compositions in island arc magmas is a consequence of the interaction between subducting slab and mantle wedge without the involvement of an oceanic island basalts component, and the slab can carry water and supply a subduction component as a fluid to the overlying mantle wedge to depths exceeding 150 km.

  19. Large scale test of wedge shaped micro strip gas counters

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Atz, S.; Aulchenko, V.; Bachmann, S.; Baiboussinov, B.; Barthe, S.; Beaumont, W.; Beckers, T.; Beißel, F.; Benhammou, Y.; Bergdolt, A. M.; Bernier, K.; Blüm, P.; Bondar, A.; Bouhali, O.; Boulogne, I.; Bozzo, M.; Brom, J. M.; Camps, C.; Chorowicz, V.; Coffin, J.; Commichau, V.; Contardo, D.; Croix, J.; De Troy, J.; Drouhin, F.; Eberlé, H.; Flügge, G.; Fontaine, J.-C.; Geist, W.; Goerlach, U.; Gundlfinger, K.; Hangarter, K.; Haroutunian, R.; Helleboid, J. M.; Henkes, Th.; Hoffer, M.; Hoffman, C.; Huss, D.; Ischebeck, R.; Jeanneau, F.; Juillot, P.; Junghans, S.; Kapp, M. R.; Kärcher, K.; Knoblauch, D.; Kräber, M.; Krauth, M.; Kremp, J.; Lounis, A.; Lübelsmeyer, K.; Maazouzi, C.; Macke, D.; Metri, R.; Mirabito, L.; Müller, Th.; Nagaslaev, V.; Neuberger, D.; Nowack, A.; Pallares, A.; Pandoulas, D.; Petertill, M.; Pooth, O.; Racca, C.; Ripp, I.; Ruoff, E.; Sauer, A.; Schmitz, P.; Schulte, R.; von Dratzig, A. Schultz; Schunk, J. P.; Schuster, G.; Schwaller, B.; Shektman, L.; Siedling, R.; Sigward, M. H.; Simonis, H. J.; Smadja, G.; Stefanescu, J.; Szczesny, H.; Tatarinov, A.; Thümmel, W. H.; Tissot, S.; Titov, V.; Todorov, T.; Tonutti, M.; Udo, F.; Vander Velde, C.; Van Doninck, W.; Van Dyck, Ch.; Vanlaer, P.; Van Lancker, L.; Verdini, P. G.; Weseler, S.; Wittmer, B.; Wortmann, R.; Zghiche, A.; Zhukov, V.

    1999-11-01

    In order to check the system aspects of the forward-backward MSGC tracker designed for the future CMS experiment at LHC, 38 trapezoidal MSGC counters assembled in six multi-substrates detector modules were built and exposed to a muon beam at the CERN SPS. Results on the gain uniformity along the wedge-shaped strip pattern and across the detector modules are shown together with measurements of the detection efficiency and the spatial resolution.

  20. Quantitative comparisons of numerical models of brittle wedge dynamics

    NASA Astrophysics Data System (ADS)

    Buiter, Susanne

    2010-05-01

    Numerical and laboratory models are often used to investigate the evolution of deformation processes at various scales in crust and lithosphere. In both approaches, the freedom in choice of simulation method, materials and their properties, and deformation laws could affect model outcomes. To assess the role of modelling method and to quantify the variability among models, we have performed a comparison of laboratory and numerical experiments. Here, we present results of 11 numerical codes, which use finite element, finite difference and distinct element techniques. We present three experiments that describe shortening of a sand-like, brittle wedge. The material properties of the numerical ‘sand', the model set-up and the boundary conditions are strictly prescribed and follow the analogue setup as closely as possible. Our first experiment translates a non-accreting wedge with a stable surface slope of 20 degrees. In agreement with critical wedge theory, all models maintain the same surface slope and do not deform. This experiment serves as a reference that allows for testing against analytical solutions for taper angle, root-mean-square velocity and gravitational rate of work. The next two experiments investigate an unstable wedge in a sandbox-like setup, which deforms by inward translation of a mobile wall. The models accommodate shortening by formation of forward and backward shear zones. We compare surface slope, rate of dissipation of energy, root-mean-square velocity, and the location, dip angle and spacing of shear zones. We show that we successfully simulate sandbox-style brittle behaviour using different numerical modelling techniques and that we obtain the same styles of deformation behaviour in numerical and laboratory experiments at similar levels of variability. The GeoMod2008 Numerical Team: Markus Albertz, Michelle Cooke, Tony Crook, David Egholm, Susan Ellis, Taras Gerya, Luke Hodkinson, Boris Kaus, Walter Landry, Bertrand Maillot, Yury Mishin

  1. Wedge-local quantum fields on a nonconstant noncommutative spacetime

    SciTech Connect

    Much, A.

    2012-08-15

    Within the framework of warped convolutions we deform the massless free scalar field. The deformation is performed by using the generators of the special conformal transformations. The investigation shows that the deformed field turns out to be wedge-local. Furthermore, it is shown that the spacetime induced by the deformation with the special conformal operators is nonconstant noncommutative. The noncommutativity is obtained by calculating the deformed commutator of the coordinates.

  2. Wedge Prism for Direction Resolved Speckle Correlation Interferometry

    SciTech Connect

    Pechersky, M.J.

    1999-01-20

    The role of a wedge prism for strain sign determination and enhancing the sensitivity for sub-fringe changes is emphasized. The design and incorporation aspects for in-plane sensitive interferometers have been described in detail. Some experimental results dealing with stress determination by laser annealing and speckle corelation interferometry are presented. The prism can also be applied to produce standardized carrier fringes in spatial phase shifting interferometry.

  3. 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

  4. Wedge-Filtering of Geomorphologic Terrestrial Laser Scan Data

    PubMed Central

    Panholzer, Helmut; Prokop, Alexander

    2013-01-01

    Terrestrial laser scanning is of increasing importance for surveying and hazard assessments. Digital terrain models are generated using the resultant data to analyze surface processes. In order to determine the terrain surface as precisely as possible, it is often necessary to filter out points that do not represent the terrain surface. Examples are vegetation, vehicles, and animals. Filtering in mountainous terrain is more difficult than in other topography types. Here, existing automatic filtering solutions are not acceptable, because they are usually designed for airborne scan data. The present article describes a method specifically suitable for filtering terrestrial laser scanning data. This method is based on the direct line of sight between the scanner and the measured point and the assumption that no other surface point can be located in the area above this connection line. This assumption is only true for terrestrial laser data, but not for airborne data. We present a comparison of the wedge filtering to a modified inverse distance filtering method (IDWMO) filtered point cloud data. Both methods use manually filtered surfaces as reference. The comparison shows that the mean error and root–mean-square-error (RSME) between the results and the manually filtered surface of the two methods are similar. A significantly higher number of points of the terrain surface could be preserved, however, using the wedge-filtering approach. Therefore, we suggest that wedge-filtering should be integrated as a further parameter into already existing filtering processes, but is not suited as a standalone solution so far. PMID:23429548

  5. Hypersingularity, electromagnetic edge condition, and an analytic hyperbolic wedge model.

    PubMed

    Li, Lifeng

    2014-04-01

    It is insufficient to consider that hypersingularity is unphysical solely based on energy considerations. With a proper combination of the two degenerate hypersingular modes, the energy-flux edge condition is satisfied. A hyperbolic wedge model is presented that is much simpler than the previous model for the purpose of studying singular characteristics of the edge fields. This model not only reproduces the sharp edge model as the wedge becomes infinitely sharp but also naturally shows how the two degenerate hypersingular modes of the sharp edge model should be combined. In an incidental study of the effect of rounding edges on numerical computation, I show that the converged results for rounded edges do not converge to a fixed value when the radius of curvature tends to zero, if the corresponding sharp edge supports hypersingularity. I also prove that introducing a small amount of absorption loss for the purpose of improving numerical convergence is effective only when the ratio of the real parts of the permittivities of the two media forming the wedge is close to -1. Finally I remark on the possible illposedness of the hypersingularity problem without imposition of the edge condition.

  6. 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.

  7. Open Access High Throughput Drug Discovery in the Public Domain: A Mount Everest in the Making

    PubMed Central

    Roy, Anuradha; McDonald, Peter R.; Sittampalam, Sitta; Chaguturu, Rathnam

    2013-01-01

    High throughput screening (HTS) facilitates screening large numbers of compounds against a biochemical target of interest using validated biological or biophysical assays. In recent years, a significant number of drugs in clinical trails originated from HTS campaigns, validating HTS as a bona fide mechanism for hit finding. In the current drug discovery landscape, the pharmaceutical industry is embracing open innovation strategies with academia to maximize their research capabilities and to feed their drug discovery pipeline. The goals of academic research have therefore expanded from target identification and validation to probe discovery, chemical genomics, and compound library screening. This trend is reflected in the emergence of HTS centers in the public domain over the past decade, ranging in size from modestly equipped academic screening centers to well endowed Molecular Libraries Probe Centers Network (MLPCN) centers funded by the NIH Roadmap initiative. These centers facilitate a comprehensive approach to probe discovery in academia and utilize both classical and cutting-edge assay technologies for executing primary and secondary screening campaigns. The various facets of academic HTS centers as well as their implications on technology transfer and drug discovery are discussed, and a roadmap for successful drug discovery in the public domain is presented. New lead discovery against therapeutic targets, especially those involving the rare and neglected diseases, is indeed a Mount Everestonian size task, and requires diligent implementation of pharmaceutical industry’s best practices for a successful outcome. PMID:20809896

  8. Resilience of SAR11 bacteria to rapid acidification in the high-latitude open ocean.

    PubMed

    Hartmann, Manuela; Hill, Polly G; Tynan, Eithne; Achterberg, Eric P; Leakey, Raymond J G; Zubkov, Mikhail V

    2016-02-01

    Ubiquitous SAR11 Alphaproteobacteria numerically dominate marine planktonic communities. Because they are excruciatingly difficult to cultivate, there is comparatively little known about their physiology and metabolic responses to long- and short-term environmental changes. As surface oceans take up anthropogenic, atmospheric CO2, the consequential process of ocean acidification could affect the global biogeochemical significance of SAR11. Shipping accidents or inadvertent release of chemicals from industrial plants can have strong short-term local effects on oceanic SAR11. This study investigated the effect of 2.5-fold acidification of seawater on the metabolism of SAR11 and other heterotrophic bacterioplankton along a natural temperature gradient crossing the North Atlantic Ocean, Norwegian and Greenland Seas. Uptake rates of the amino acid leucine by SAR11 cells as well as other bacterioplankton remained similar to controls despite an instant ∼50% increase in leucine bioavailability upon acidification. This high physiological resilience to acidification even without acclimation, suggests that open ocean dominant bacterioplankton are able to cope even with sudden and therefore more likely with long-term acidification effects.

  9. Mechanism of formation of subnanosecond current front in high-voltage pulse open discharge

    NASA Astrophysics Data System (ADS)

    Schweigert, I. V.; Alexandrov, A. L.; Zakrevsky, Dm. E.; Bokhan, P. A.

    2014-11-01

    The mechanism of subnanosecond current front rise observed previously in the experiment in high-voltage pulse open discharge in helium is studied in kinetic particle-in-cell simulations. The Boltzmann equations for electrons, ions, and fast atoms are solved self-consistently with the Poisson equations for the electrical potential. The partial contributions to the secondary electron emission from the ions, fast atoms, photons, and electrons, bombarding the electrode, are calculated. In simulations, as in the experiment, the discharge glows between two symmetrical cathodes and the anode grid in the midplane at P =6 Torr and the applied voltage of 20 kV. The electron avalanche development is considered for two experimental situations during the last stage of breakdown: (i) with constant voltage and (ii) with decreasing voltage. For case (i), the subnanosecond current front rise is set by photons from the collisional excitation transfer reactions. For the case (ii), the energetic electrons swamp the cathode during voltage drop and provide the secondary electron emission for the subnanosecond current rise, observed in the experiment.

  10. Screensaver: an open source lab information management system (LIMS) for high throughput screening facilities

    PubMed Central

    2010-01-01

    Background Shared-usage high throughput screening (HTS) facilities are becoming more common in academe as large-scale small molecule and genome-scale RNAi screening strategies are adopted for basic research purposes. These shared facilities require a unique informatics infrastructure that must not only provide access to and analysis of screening data, but must also manage the administrative and technical challenges associated with conducting numerous, interleaved screening efforts run by multiple independent research groups. Results We have developed Screensaver, a free, open source, web-based lab information management system (LIMS), to address the informatics needs of our small molecule and RNAi screening facility. Screensaver supports the storage and comparison of screening data sets, as well as the management of information about screens, screeners, libraries, and laboratory work requests. To our knowledge, Screensaver is one of the first applications to support the storage and analysis of data from both genome-scale RNAi screening projects and small molecule screening projects. Conclusions The informatics and administrative needs of an HTS facility may be best managed by a single, integrated, web-accessible application such as Screensaver. Screensaver has proven useful in meeting the requirements of the ICCB-Longwood/NSRB Screening Facility at Harvard Medical School, and has provided similar benefits to other HTS facilities. PMID:20482787

  11. Open access high throughput drug discovery in the public domain: a Mount Everest in the making.

    PubMed

    Roy, Anuradha; McDonald, Peter R; Sittampalam, Sitta; Chaguturu, Rathnam

    2010-11-01

    High throughput screening (HTS) facilitates screening large numbers of compounds against a biochemical target of interest using validated biological or biophysical assays. In recent years, a significant number of drugs in clinical trails originated from HTS campaigns, validating HTS as a bona fide mechanism for hit finding. In the current drug discovery landscape, the pharmaceutical industry is embracing open innovation strategies with academia to maximize their research capabilities and to feed their drug discovery pipeline. The goals of academic research have therefore expanded from target identification and validation to probe discovery, chemical genomics, and compound library screening. This trend is reflected in the emergence of HTS centers in the public domain over the past decade, ranging in size from modestly equipped academic screening centers to well endowed Molecular Libraries Probe Centers Network (MLPCN) centers funded by the NIH Roadmap initiative. These centers facilitate a comprehensive approach to probe discovery in academia and utilize both classical and cutting-edge assay technologies for executing primary and secondary screening campaigns. The various facets of academic HTS centers as well as their implications on technology transfer and drug discovery are discussed, and a roadmap for successful drug discovery in the public domain is presented. New lead discovery against therapeutic targets, especially those involving the rare and neglected diseases, is indeed a Mount Everestonian size task, and requires diligent implementation of pharmaceutical industry's best practices for a successful outcome.

  12. High throughput synthesis of polyesters using entropically driven ring-opening polymerizations.

    PubMed

    Kamau, Stephen D; Hodge, Philip; Williams, Richard T; Stagnaro, Paola; Conzatti, Lucia

    2008-01-01

    Copolyesters were synthesized in a high throughput (HT) manner and in high yield on ca. a 90 mg scale using entropically driven ring-opening polymerizations (ED-ROPs). This synthetic approach is a valuable addition to the HT polymer synthesis arsenal in that it allows condensation-type polymers with relatively large repeat units, such as those in poly(ethylene terephthalate) and poly(butylene terephthalate), to be obtained easily. The synthetic procedure involved taking mixtures of the appropriate macrocyclic oligoesters and heating them together under neat conditions at 250-300 degrees C for 2 h in the presence of 0.1 mol % of di- n-butyltin oxide or tetra- n-butylammonium tetrafluoroborate. In most cases Mw values were >25,000 and, as expected for ED-ROPs, the polydispersity indices were close to 2.0. Higher molecular weights could be obtained by using longer reaction times, but this might lead to product decomposition. The method worked well for esters formally derived from aliphatic or aromatic acids and alcohols, but less well for esters derived from phenols. Attempts were also made to synthesize copolymers by mixing together the two homopolymers and heating with a catalyst. These reactions were successful in a few instances, but generally, they were not. This is probably because the homopolymers did not mix well. An aluminum reaction block with 36 wells lined with Teflon cups, that fitted snugly in a cylindrical Buchi oven, was the most successful method for carrying out syntheses in an HT manner.

  13. Anomalous open-circuit voltage from a high-Tc superconducting dynamo

    NASA Astrophysics Data System (ADS)

    Bumby, C. W.; Jiang, Zhenan; Storey, J. G.; Pantoja, A. E.; Badcock, R. A.

    2016-03-01

    We report on the behavior of a high-Tc superconducting (HTS) homopolar dynamo which outputs a DC open-circuit voltage when the stator is in the superconducting state, but behaves as a conventional AC alternator when the stator is in the normal state. We observe that this time-averaged DC voltage arises from a change in the shape of the AC voltage waveform that is obtained from a normal conducting stator. The measured DC voltage is proportional to frequency, and decreases with increasing flux gap between the rotor magnet and the HTS stator wire. We observe that the DC output voltage decreases to zero at large flux gaps, although small differences between the normal-conducting and superconducting waveforms are still observed, which we attribute to screening currents in the HTS stator wire. Importantly, the normalised pulse shape is found to be a function of the rotor position angle only. Based on these observations, we suggest that the origin of this unexpected DC effect can be explained by a model first proposed by Giaever, which considers the impact of time-varying circulating eddy currents within the HTS stator wire. Such circulating currents form a superconducting shunt path which "short-circuits" the high field region directly beneath the rotor magnet, at those points in the cycle when the rotor magnet partially overlaps the superconducting stator wire. This reduces the output voltage from the device during these periods of the rotor cycle, leading to partial rectification of the output voltage waveform and hence the emergence of a time-averaged DC voltage.

  14. Synthesis of Highly Porous Coordination Polymers with Open Metal Sites for Enhanced Gas Uptake and Separation.

    PubMed

    Song, Kyung Seob; Kim, Daeok; Polychronopoulou, Kyriaki; Coskun, Ali

    2016-10-12

    Metal-containing amorphous microporous polymers are an emerging class of functional porous materials in which the surface properties and functions of polymers are dictated by the nature of the metal ions incorporated into the framework. In an effort to introduce coordinatively unsaturated metal sites into the porous polymers, we demonstrate herein an aqueous-phase synthesis of porous coordination polymers (PCPs) incorporating bis(o-diiminobenzosemiquinonato)-Cu(II) or -Ni(II) bridges by simply reacting hexaminotriptycene with CuSO4·5H2O [Cu(II)-PCP] or NiCl2·6H2O [Ni(II)-PCP] in H2O. The resulting polymers showed surface areas of up to 489 m(2) g(-1) along with a narrow pore size distribution. The presence of open metal sites significantly improved the gas affinity of these frameworks, leading to an exceptional isosteric heat of adsorption of 10.3 kJ·mol(-1) for H2 at zero coverage. The high affinities of Cu(II)- and Ni(II)-PCPs toward CO2 prompted us to investigate the removal of CO2 from natural and landfill gas conditions. We found that the higher affinity of Cu(II)-PCP compared to that of Ni(II)-PCP not only allowed for the tuning of the affinity of CO2 molecules toward the sorbent, but also led to an exceptional CO2/CH4 selectivity of 35.1 for landfill gas and 20.7 for natural gas at 298 K. These high selectivities were further verified by breakthrough measurements under the simulated natural and landfill gas conditions, in which both Cu(II)- and Ni(II)-PCPs showed complete removal of CO2. These results clearly demonstrate the promising attributes of metal-containing porous polymers for gas storage and separation applications.

  15. Quantitative testing critical-taper wedge theory with distinct-element modeling and the role of dynamics in controlling wedge tapers

    NASA Astrophysics Data System (ADS)

    Strayer, Luther; Suppe, John

    2014-05-01

    Critical-taper wedge mechanics (e.g. Davis, et al. 1983, Dahlen 1990) provides fundamental relationships between the observed tapered geometries of fold-and-thrust belts and accretionary wedges and their detachment and wedge strengths. This theory has given diverse insight into kinematics, roles of erosion and sedimentation, and the morphology of compressive mountain belts, much of which has been aided by extensive analog and numerical modeling. The field has grown large, with several thousand papers addressing real-world, analog, and numerical wedges (cf. Buiter 2012). The majority of the insight has been qualitative, but nevertheless quite influential in our current understanding of mountain belts and submarine wedges. In contrast, quantitative applications of wedge theory, either to nature or models, has been rather limited because of the complexity of most wedge equations. It it is easy to become "lost in parameter space" with many strength parameters that are difficult to constrain or have ambiguous meaning, given real-world data and observations. Recently wedge theory has been recast into a very simple form (Suppe 2007; Yeh and Suppe 2014) that provides an unambiguous relationship between the observed covariation of surface slope α with detachment dip β and the wedge W and fault F strengths with few assumptions. In the real world we have limited knowledge of strengths, forces, fluid pressures and earthquake history, or the relationship between strength heterogeneity and structural style, or to what extent the strength of a wedge is an evolving macroscopic property (e.g. folding, imbrications and strain localization) or a material property. The well-defined relationship between wedge taper and global strength makes numerical wedges an ideal tool for the study of compressive mountain belts. In this work: [1] We successfully test this simpler quantitative wedge theory over a very wide range of wedge strengths and structural styles using distinct

  16. 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.

  17. Numerical modeling of mantle wedge processes and exhumation of UHP mantle in subduction zones

    NASA Astrophysics Data System (ADS)

    Gorczyk, W.; Gerya, T. V.; Guillot, S.; Connolly, J. A.; Yuen, D.

    2007-12-01

    The upwelling of subduction generated partially molten rocks is potentially a mechanism for the exhumation of UHP rocks through the mantle wedge. We investigated this processes using a 2-D coupled petrological- thermomechanical model that incorporates slab dehydration and water transport as well as partial melting of mantle and crustal rocks. This approach allows us to study the dynamics of mantle wedge processes including evolution of partially molten plumes and their interaction with surrounding dry mantle. To study the internal structure of the plumes we used ultra-high resolution numerical simulations with 10 billion active markers to detail the internal structure of natural plumes originating from the slab. The plumes consist of partially molten hydrated peridotite, dry solid mantle and subducted oceanic crust, which may comprise up to 12 volume % of the plume. As the plumes grow and mature these materials mix chaotically resulting in attenuation and duplication of the original layering on scales of 1-1000 m. Comparison of numerical results with geological observations from the Horoman ultramafic complex in Japan suggests that mixing and differentiation processes related to development of partially molten plumes above slabs may be responsible for strongly layered lithologically mixed (marble cake) structure of asthenospheric mantle wedges. The recent discovery of garnet bearing peridotites in the subduction zone of the Great Antilles in Hispaniola has raised questions about the process that leads to their exhumation. To evaluate whether upwelling plumes are a plausible exhumation mechanism we investigated the dynamics of subduction of slow spreading ridges. The results show that subduction of strongly serpentinized oceanic plate causes strong dehydration of the slab and leads to a rheological weakening of the interface between subducting and overriding plate. This weakening triggers trench retreat and massive asthenospheric upwelling into the gap between the

  18. 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.

  19. Intermediate and old age Open Clusters science case for high resolution spectroscopy

    NASA Astrophysics Data System (ADS)

    Jordi, C.; Carrera, R.; Balaguer-Núnez, L.; Casamiquela, L.

    2017-03-01

    Open Clusters are dynamically-bound groups of stars that formed from the same giant molecular cloud, having a similar age and bulk chemical composition. Open Clusters are key objects for studying the formation and evolution of the Galactic disk. They are targets in on-going large spectroscopic surveys like Gaia-ESO and OCCASO surveys. We discuss the science case of the intermediate age and old Open Clusters for WEAVE, the upcoming multifiber spectroscopic facility in the WHT. In particular we do an overview of the target selection and the survey strategy. Additionally, the impact of the discovery of new clusters by Gaia space mission is discussed.

  20. 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

  1. 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

  2. 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

  3. First Year Progress Report on Project Open, Ona Junior High School, Cabell County, West Virginia, 1977-78 Project Year.

    ERIC Educational Resources Information Center

    Murwin, Scott; Murray, Michael

    As part of Project Open (see related documents listed below), unified arts and industrial arts curricula were developed and implemented at Ona Junior High School in West Virginia. The unified arts program combines the four subject areas of art, home economics, music, and industrial arts. It is a two-year required course for all seventh and eighth…

  4. Open data policy and data sharing in Astroparticle Physics: the case for high-energy multi-messenger astronomy

    NASA Astrophysics Data System (ADS)

    Spiro, M.

    2016-05-01

    This paper is a position paper on open data policy and data sharing in Astroparticle Physics, focusing on the case of high-energy multi-messenger astronomy. It is presented on behalf of ApPIC, Astroparticle Physics International Committee [1], IUPAP (International Union for Pure and Applied Physics) working group 10.

  5. 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.

  6. A phenomenological model for intergranular failure by r-type and wedge-type cavitation

    SciTech Connect

    Lee, S.B.; Miller, A.K.

    1995-07-01

    Equations to predict local intergranular failure (by r-type and wedge-type cavitation and the coupling between them) have been developed. The derivation has utilized physically based concepts such as thermal activation of the controlling processes, wedge cracking driven by grain boundary sliding, and cavity growth driven by diffusion. It has also been based upon phenomenological observations such as the variation in the steady-state creep rate with stress and temperature, incomplete healing of cavities under compression, and differences in life under slow-fast and fast-slow cycling. The model has been tested against data on the low-cycle fatigue life of 304 stainless steel under unequal ramp rates. The new equations simulate, for example, the differences in life produced by slow-fast, fast-slow, and equal ramp rate cycling in terms of their effects on internal cavitation. Together with the new equations` ability to treat monotonic creep rupture, these comparisons demonstrate that the intergranular failure equations are capable of simulating a number of phenomena of importance in life prediction for high-temperature structures.

  7. 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.

  8. Compact multi-projection 3D display using a wedge prism

    NASA Astrophysics Data System (ADS)

    Park, Soon-gi; Lee, Chang-Kun; Lee, Byoungho

    2015-03-01

    We propose a compact multi-projection system based on integral floating method with waveguide projection. Waveguide projection can reduce the projection distance by multiple folding of optical path inside the waveguide. The proposed system is composed of a wedge prism, which is used as a waveguide, multiple projection-units, and an anisotropic screen made of floating lens combined with a vertical diffuser. As the projected image propagates through the wedge prism, it is reflected at the surfaces of prism by total internal reflections, and the final view image is created by the floating lens at the viewpoints. The position of view point is decided by the lens equation, and the interval of view point is calculated by the magnification of collimating lens and interval of projection-units. We believe that the proposed method can be useful for implementing a large-scale autostereoscopic 3D system with high quality of 3D images using projection optics. In addition, the reduced volume of the system will alleviate the restriction of installment condition, and will widen the applications of a multi-projection 3D display.

  9. Joule-Heating-Induced Damage in Cu-Al Wedge Bonds Under Current Stressing

    NASA Astrophysics Data System (ADS)

    Yang, Tsung-Han; Lin, Yu-Min; Ouyang, Fan-Yi

    2014-01-01

    Copper wires are increasingly used to replace gold wires in wire-bonding technology owing to their better electrical properties and lower cost. However, not many studies have been conducted on electromigration-induced failure of Cu wedge bonds on Al metallization. In this study, we investigated the failure mechanism of Cu-Al wedge bonds under high current stressing from 4 × 104 A/cm2 to 1 × 105 A/cm2 at ambient temperature of 175°C. The resistance evolution of samples during current stressing and the microstructure of the joint interface between the Cu wire and Al-Si bond pad were examined. The results showed that abnormal crack formation accompanying significant intermetallic compound growth was observed at the second joint of the samples, regardless of the direction of electric current for both current densities of 4 × 104 A/cm2 and 8 × 104 A/cm2. We propose that this abnormal crack formation at the second joint is mainly due to the higher temperature induced by the greater Joule heating at the second joint for the same current stressing, because of its smaller bonded area compared with the first joint. The corresponding fluxes induced by the electric current and chemical potential difference between Cu and Al were calculated and compared to explain the failure mechanism. For current density of 1 × 105 A/cm2, the Cu wire melted within 0.5 h owing to serious Joule heating.

  10. 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.

  11. 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.

  12. 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

  13. Thermodynamic and kinetic supercooling of liquid in a wedge pore.

    PubMed

    Nowak, Dominika; Heuberger, Manfred; Zäch, Michael; Christenson, Hugo K

    2008-10-21

    Cyclohexane allowed to capillary condense from vapor in an annular wedge pore of mica in a surface force apparatus (SFA) remains liquid down to at least 14 K below the bulk melting-point T(m). This is an example of supercooling of a liquid due to confinement, like melting-point depression in porous media. In the wedge pore, however, the supercooled liquid is in equilibrium with vapor, and the amount of liquid (and thereby the radius of curvature r of the liquid-vapor interface) depends on the surface tension gamma(LV) of the liquid, not the interfacial tension between the solid and liquid. At coexistence r is inversely proportional to the temperature depression DeltaT below T(m), in accordance with a recently proposed model [P. Barber, T. Asakawa, and H. K. Christenson, J. Phys. Chem. C 111, 2141 (2007)]. We have now extended this model to include effects due to the temperature dependence of both the surface tension and the enthalpy of melting. The predictions of the improved model have been quantitatively verified in experiments using both a Mark IV SFA and an extended surface force apparatus (eSFA). The three-layer interferometer formed by the two opposing, backsilvered mica surfaces in a SFA was analyzed by conventional means (Mark IV) and by fast spectral correlation of up to 40 fringes (eSFA). We discuss the absence of freezing in the outermost region of the wedge pore down to 14 K below T(m) and attribute it to nonequilibrium (kinetic) supercooling, whereas the inner region of the condensate is thermodynamically supercooled.

  14. Mask-Free Patterning of High-Conductivity Metal Nanowires in Open Air by Spatially Modulated Femtosecond Laser Pulses.

    PubMed

    Wang, Andong; Jiang, Lan; Li, Xiaowei; Liu, Yang; Dong, Xianzi; Qu, Liangti; Duan, Xuanming; Lu, Yongfeng

    2015-10-28

    A novel high-resolution nanowire fabrication method is developed by thin-film patterning using a spatially modulated femtosecond laser pulse. Deep subwavelength (≈1/13 of the laser wavelength) and high conductivity (≈1/4 of the bulk gold) nanowires are fabricated in the open air without using masks, which offers a single-step arbitrary direct patterning approach for electronics, plasmonics, and optoelectronics nanodevices.

  15. Highly Selective Adsorption of Ethylene over Ethane in a MOF Featuring the Combination of Open Metal Site and -Complexation

    DOE PAGES

    Zhang, Yiming; Li, Baiyan; Wu, Zili; ...

    2015-01-01

    The introduction of the combination of open metal site (OMS) and -complexation into MOF has led to very high ethylene/ethane adsorption selectivity at 318K, as illustrated in the context of MIL-101-Cr-SO3Ag. The interactions with ethylene from both OMS and -complexation in MIL-101-Cr-SO3Ag have been investigated by in situ IR spectroscopic studies and computational calculations, which suggest -complexation contributes dominantly to the high ethylene/ethane adsorption selectivity.

  16. Mechanics of brittle transpressional wedges: constraints from complementary analogue and numerical modelling

    NASA Astrophysics Data System (ADS)

    Leever, K.; Thieulot, C.; Oncken, O.

    2012-12-01

    Analogue tectonic modeling combined with digital image analysis (PIV) gives high resolution constraints on the kinematics of (crustal) deformation. Observations are, however, limited to the model surface. While 3D numerical codes suffer much lower resolution than their analogue counterparts, they do allow unrestrained access to the internal dynamics. We apply both methods to constrain the mechanics of brittle transpressional wedges as fully as possible, allowing for a validation of existing analytical models. In this contribution, we highlight the strong control of erosional unloading on strain partitioning in highly oblique convergence. Results from analogue modelling Analogue tectonic transpression models with a brittle rheology and driven by constant basal kinematic boundary conditions were run at convergence angles of 10°, 20° and 30°. In one end member series, no erosion was applied. In the other series, the wedge topography was fully removed at 3 cm displacement increments. The models were observed with digital cameras. Using PIV, displacement fields were calculated and the slip on individual fault segments was derived. The analogue models reveal a strong dependence of fault kinematics on erosional unloading. The model series without erosion show a two-stage evolution. An initial, transient "oblique wedge" stage with oblique slip on pro- and retro-shear is followed by a steady state stage of "strain partitioning", in which slip is partitioned between strike-slip on a sub-vertical fault above the velocity discontinuity and oblique slip (20-30° obliquity, depending on the convergence angle) on the pro-shears. In this stage, the retro-shear accommodates near-orthogonal slip (5-10° obliquity). In the model series with erosion, a strike-slip fault develops as well. However, probably due to its inclined geometry, a larger component of the boundary-parallel displacement remains to be accommodated on the pro-shears. Slip on the retro-shear remains highly oblique

  17. High-energy-density electron jet generation from an opening gold cone filled with near-critical-density plasma

    SciTech Connect

    Yu, T. P. Shao, F. Q.; Zou, D. B.; Ge, Z. Y.; Zhang, G. B.; Wang, W. Q.; Li, X. H.; Liu, J. X.; Ouyang, J. M.; Yu, W.; Luan, S. X.; Wang, J. W.; Wong, A. Y.

    2015-01-14

    By using two-dimensional particle-in-cell simulations, we propose a scheme for strong coupling of a petawatt laser with an opening gold cone filled with near-critical-density plasmas. When relevant parameters are properly chosen, most laser energy can be fully deposited inside the cone with only 10% leaving the tip opening. Due to the asymmetric ponderomotive acceleration by the strongly decayed laser pulse, high-energy-density electrons with net laser energy gain are accumulated inside the cone, which then stream out of the tip opening continuously, like a jet. The jet electrons are fully relativistic, with speeds around 0.98−0.998 c and densities at 10{sup 20}/cm{sup 3} level. The jet can keep for a long time over 200 fs, which may have diverse applications in practice.

  18. Nonlinear Instability of Hypersonic Flow past a Wedge

    NASA Technical Reports Server (NTRS)

    Seddougui, Sharon O.; Bassom, Andrew P.

    1991-01-01

    The nonlinear stability of a compressible flow past a wedge is investigated in the hypersonic limit. The analysis follows the ideas of a weakly nonlinear approach. Interest is focussed on Tollmien-Schlichting waves governed by a triple deck structure and it is found that the attached shock can profoundly affect the stability characteristics of the flow. In particular, it is shown that nonlinearity tends to have a stabilizing influence. The nonlinear evolution of the Tollmien-Schlichting mode is described in a number of asymptotic limits.

  19. Detection of unsuspected ovarian pregnancy by wedge resection

    PubMed Central

    Helde, M. D.; Campbell, J. S.; Himaya, A.; Nuyens, J. J.; Cowley, F. C.; Hurteau, G. D.

    1972-01-01

    Five follicular ovarian implantations occurred among 200 ectopic pregnancies encountered during a 14-year period. Abortions from impregnated follicles may cause hemoperitoneum more often than is generally suspected. Wedge resection or cystectomy to ensure hemostasis provides tissue for histological examination, without which ruptured ovarian pregnancy may masquerade as rupture of a corpus luteum with hemorrhage (“ovarian apoplexy”). Including patients reported here, IUCD users have within the past five years accounted for about 10% of all ovarian pregnancies recorded in English. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6 PMID:5057958

  20. Open Educational Resources for Blended Learning in High Schools: Overcoming Impediments in Developing Countries

    ERIC Educational Resources Information Center

    Larson, Richard C.; Murray, M. Elizabeth

    2008-01-01

    With today's computer and telecommunications technologies, every young person can have a quality education regardless of his or her place of birth. This is the dream that Open Educational Resources (OERs), when viewed as a right rather than a privilege, are directed to realize. For developing countries, we propose a type of OER initiative that…

  1. High-resolution structure of the open NaK channel

    SciTech Connect

    Alam, Amer; Jiang, Youxing

    2009-04-08

    We report the crystal structure of the nonselective cation channel NaK from Bacillus cereus at a resolution of 1.6 {angstrom}. The structure reveals the intracellular gate in an open state, as opposed to the closed form reported previously, making NaK the only channel for which the three-dimensional structures of both conformations are known. Channel opening follows a conserved mechanism of inner helix bending using a flexible glycine residue, the gating hinge, seen in MthK and most other tetrameric cation channels. Additionally, distinct inter and intrasubunit rearrangements involved in channel gating are seen and characterized for the first time along with inner helix twisting motions. Furthermore, we identify a residue deeper within the cavity of the channel pore, Phe92, which is likely to form a constriction point within the open pore, restricting ion flux through the channel. Mutating this residue to alanine causes a subsequent increase in ion-conduction rates as measured by {sup 86}Rb flux assays. The structures of both the open and closed conformations of the NaK channel correlate well with those of equivalent K{sup +} channel conformations, namely MthK and KcsA, respectively.

  2. Resilient seal ring assembly with spring means applying force to wedge member. [cryogenic applications

    NASA Technical Reports Server (NTRS)

    Myers, W. N.; Hein, L. A. (Inventor)

    1983-01-01

    A ring seal adapted for installation in an annular recess between a housing and a rotating or reciprocating shaft is described. The seal consists of a resilient ring cup member having a ring wedge member inserted in the center recess of the cup member to wedge the opposing lips of the cup member outwardly into a sealing relationship. A spring maintains the force against the wedge member.

  3. 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

    2009-12-06

    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.

  4. A Preliminary Examination of the Cost Savings and Learning Impacts of Using Open Textbooks in Middle and High School Science Classes

    ERIC Educational Resources Information Center

    Wiley, David; Hilton, John Levi, III; Ellington, Shelley; Hall, Tiffany

    2012-01-01

    Proponents of open educational resources claim that significant cost savings are possible when open textbooks displace traditional textbooks in the classroom. Over a period of two years, we worked with 20 middle and high school science teachers (collectively teaching approximately 3,900 students) who adopted open textbooks to understand the…

  5. Deviation of tracheal pressure from airway opening pressure during high-frequency oscillatory ventilation in a porcine lung model.

    PubMed

    Johannes, Amélie; Zollhoefer, Bernd; Eujen, Ulrike; Kredel, Markus; Rauch, Stefan; Roewer, Norbert; Muellenbach, Ralf M

    2013-04-01

    Oxygenation during high-frequency oscillatory ventilation is secured by a high level of mean airway pressure. Our objective was to identify a pressure difference between the airway opening of the respiratory circuit and the trachea during application of different oscillatory frequencies. Six female Pietrain pigs (57.1 ± 3.6 kg) were first ventilated in a conventional mechanical ventilation mode. Subsequently, the animals were switched to high-frequency oscillatory ventilation by setting mean airway opening pressure 5 cmH(2)O above the one measured during controlled mechanical ventilation. Measurements at the airway opening and at tracheal levels were performed in healthy lungs and after induction of acute lung injury by surfactant depletion. During high-frequency oscillatory ventilation, the airway opening pressure was set at a constant level. The pressure amplitude was fixed at 90 cmH(2)O. Starting from an oscillatory frequency of 3 Hz, the frequency was increased in steps of 3 Hz to 15 Hz and then decreased accordingly. At each frequency, measurements were performed in the trachea through a side-lumen of the endotracheal tube and the airway opening pressure was recorded. The pressure difference was calculated. At every oscillatory frequency, a pressure loss towards the trachea could be shown. This pressure difference increased with higher oscillatory frequencies (3 Hz 2.2 ± 2.1 cmH(2)O vs. 15 Hz 7.5 ± 1.8 cmH(2)O). The results for healthy and injured lungs were similar. Tracheal pressures decreased with higher oscillatory frequencies. This may lead to pulmonary derecruitment. This has to be taken into consideration when increasing oscillatory frequencies and differentiated pressure settings are mandatory.

  6. Observing lysozyme's closing and opening motions by high-resolution single-molecule enzymology.

    PubMed

    Akhterov, Maxim V; Choi, Yongki; Olsen, Tivoli J; Sims, Patrick C; Iftikhar, Mariam; Gul, O Tolga; Corso, Brad L; Weiss, Gregory A; Collins, Philip G

    2015-06-19

    Single-molecule techniques can monitor the kinetics of transitions between enzyme open and closed conformations, but such methods usually lack the resolution to observe the underlying transition pathway or intermediate conformational dynamics. We have used a 1 MHz bandwidth carbon nanotube transistor to electronically monitor single molecules of the enzyme T4 lysozyme as it processes substrate. An experimental resolution of 2 μs allowed the direct recording of lysozyme's opening and closing transitions. Unexpectedly, both motions required 37 μs, on average. The distribution of transition durations was also independent of the enzyme's state: either catalytic or nonproductive. The observation of smooth, continuous transitions suggests a concerted mechanism for glycoside hydrolysis with lysozyme's two domains closing upon the polysaccharide substrate in its active site. We distinguish these smooth motions from a nonconcerted mechanism, observed in approximately 10% of lysozyme openings and closings, in which the enzyme pauses for an additional 40-140 μs in an intermediate, partially closed conformation. During intermediate forming events, the number of rate-limiting steps observed increases to four, consistent with four steps required in the stepwise, arrow-pushing mechanism. The formation of such intermediate conformations was again independent of the enzyme's state. Taken together, the results suggest lysozyme operates as a Brownian motor. In this model, the enzyme traces a single pathway for closing and the reverse pathway for enzyme opening, regardless of its instantaneous catalytic productivity. The observed symmetry in enzyme opening and closing thus suggests that substrate translocation occurs while the enzyme is closed.

  7. Contact and crack problems for an elastic wedge. [stress concentration in elastic half spaces

    NASA Technical Reports Server (NTRS)

    Erdogan, F.; Gupta, G. D.

    1974-01-01

    The contact and the crack problems for an elastic wedge of arbitrary angle are considered. The problem is reduced to a singular integral equation which, in the general case, may have a generalized Cauchy kernel. The singularities under the stamp as well as at the wedge apex were studied, and the relevant stress intensity factors are defined. The problem was solved for various wedge geometries and loading conditions. The results may be applicable to certain foundation problems and to crack problems in symmetrically loaded wedges in which cracks initiate from the apex.

  8. Late Holocene ice wedges near Fairbanks, Alaska, USA: environmental setting and history of growth.

    USGS Publications Warehouse

    Hamilton, T.D.; Ager, T.A.; Robinson, S.W.

    1983-01-01

    Test trenches excavated into muskeg near Fairbanks in 1969 exposed a polygonal network of active ice wedges. The history of ice-wedge growth shows that wedges can form and grow to more than 1m apparent width under mean annual temperatures that probably are close to those of the Fairbanks area today (-3.5oC) and under vegetation cover similar to that of the interior Alaskan boreal forest. The commonly held belief that ice wedges develop only below mean annual air temperatures of -6 to -8oC in the zone of continuous permafrost is invalid.-from Authors

  9. High-resolution retinal imaging through open-loop adaptive optics.

    PubMed

    Li, Chao; Xia, Mingliang; Li, Dayu; Mu, Quanquan; Xuan, Li

    2010-01-01

    Using the liquid crystal spatial light modulator (LC-SLM) as the wavefront corrector, an open-loop adaptive optics (AO) system for fundus imaging in vivo is constructed. Compared with the LC-SLM closed-loop AO system, the light energy efficiency is increased by a factor of 2, which is helpful for the safety of fundus illumination in vivo. In our experiment, the subjective accommodation method is used to precorrect the defocus aberration, and three subjects with different myopia 0, -3, and -5 D are tested. Although the residual wavefront error after correction cannot to detected, the fundus images adequately demonstrate that the imaging system reaches the resolution of a single photoreceptor cell through the open-loop correction. Without dilating and cyclopleging the eye, the continuous imaging for 8 s is recorded for one of the subjects.

  10. High-resolution retinal imaging through open-loop adaptive optics

    NASA Astrophysics Data System (ADS)

    Li, Chao; Xia, Mingliang; Li, Dayu; Mu, Quanquan; Xuan, Li

    2010-07-01

    Using the liquid crystal spatial light modulator (LC-SLM) as the wavefront corrector, an open-loop adaptive optics (AO) system for fundus imaging in vivo is constructed. Compared with the LC-SLM closed-loop AO system, the light energy efficiency is increased by a factor of 2, which is helpful for the safety of fundus illumination in vivo. In our experiment, the subjective accommodation method is used to precorrect the defocus aberration, and three subjects with different myopia 0, -3, and -5 D are tested. Although the residual wavefront error after correction cannot to detected, the fundus images adequately demonstrate that the imaging system reaches the resolution of a single photoreceptor cell through the open-loop correction. Without dilating and cyclopleging the eye, the continuous imaging for 8 s is recorded for one of the subjects.

  11. 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.

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

    PubMed

    Work, T M; Rameyer, R A

    1999-07-01

    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.

  13. Growth and mixing dynamics of mantle wedge plumes

    NASA Astrophysics Data System (ADS)

    Gorczyk, Weronika; Gerya, Taras V.; Connolly, James A. D.; Yuen, David A.

    2007-07-01

    Recent work suggests that hydrated partially molten thermal-chemical plumes that originate from subducted slab as a consequence of Rayleigh-Taylor instability are responsible for the heterogeneous composition of the mantle wedge. We use a two-dimensional ultrahigh-resolution numerical simulation involving 10 × 109 active markers to anticipate the detailed evolution of the internal structure of natural plumes beneath volcanic arcs in intraoceanic subduction settings. The plumes consist of partially molten hydrated peridotite, dry solid mantle, and subducted oceanic crust, which may compose as much as 12% of the plume. As plumes grow and mature these materials mix chaotically, resulting in attenuation and duplication of the original layering on scales of 1-1000 m. Comparison of numerical results with geological observations from the Horoman ultramafic complex in Japan suggests that mixing and differentiation processes related to development of partially molten plumes above slabs may be responsible for the strongly layered lithologically mixed (marble cake) structure of asthenospheric mantle wedges.

  14. Magmatic implications of mantle wedge plumes: Experimental study

    NASA Astrophysics Data System (ADS)

    Castro, A.; Gerya, T. V.

    2008-06-01

    Numerical and laboratory experiments beside natural observations suggest that hydration and partial melting along the subducting slab can trigger Rayleigh-Taylor instabilities that evolve into partially molten diapiric structures ("cold plumes") that rise through the hot asthenospheric wedge. Mixed cold plumes composed of tectonic melanges derived from subduction channels can transport the fertile subducted crustal materials towards hotter zones of the suprasubduction mantle wedge leading to the formation of silicic melts. We investigate magmatic consequences of this plausible geodynamic scenario by using an experimental approach. Melt compositions, fertility and reaction between silicic melts and the peridotite mantle (both hydrous and dry) were tested by means of piston-cylinder experiments at conditions of 1000°C and pressures of 2.0 and 2.5GPa. The results indicate that silicic melts of trondhjemite and granodiorite compositions may be produced in the ascending mixed plume megastructures. Our experiments show that the formation of an Opx-rich reaction band, developed at the contact between the silicic melts and the peridotite, protect silicic melts from further reaction in contrast to the classical view that silicic melts are completely consumed in the mantle. The mixed, mantle-crust isotopic signatures which are characteristic of many calc-alkaline batholiths are also expected from this petrogenetic scenario.

  15. Relation of the auroral substorm to the substorm current wedge

    NASA Astrophysics Data System (ADS)

    McPherron, Robert L.; Chu, Xiangning

    2016-12-01

    The auroral substorm is an organized sequence of events seen in the aurora near midnight. It is a manifestation of the magnetospheric substorm which is a disturbance of the magnetosphere brought about by the solar wind transfer of magnetic flux from the dayside to the tail lobes and its return through the plasma sheet to the dayside. The most dramatic feature of the auroral substorm is the sudden brightening and poleward expansion of the aurora. Intimately associated with this expansion is a westward electrical current flowing across the bulge of expanding aurora. This current is fed by a downward field-aligned current (FAC) at its eastern edge and an upward current at its western edge. This current system is called the substorm current wedge (SCW). The SCW forms within a minute of auroral expansion. FAC are created by pressure gradients and field line bending from shears in plasma flow. Both of these are the result of pileup and diversion of plasma flows in the near-earth plasma sheet. The origins of these flows are reconnection sites further back in the tail. The auroral expansion can be explained by a combination of a change in field line mapping caused by the substorm current wedge and a tailward growth of the outer edge of the pileup region. We illustrate this scenario with a complex substorm and discuss some of the problems associated with this interpretation.

  16. OnEarth: An Open Source Solution for Efficiently Serving High-Resolution Mapped Image Products

    NASA Astrophysics Data System (ADS)

    Thompson, C. K.; Plesea, L.; Hall, J. R.; Roberts, J. T.; Cechini, M. F.; Schmaltz, J. E.; Alarcon, C.; Huang, T.; McGann, J. M.; Chang, G.; Boller, R. A.; Ilavajhala, S.; Murphy, K. J.; Bingham, A. W.

    2013-12-01

    This presentation introduces OnEarth, a server side software package originally developed at the Jet Propulsion Laboratory (JPL), that facilitates network-based, minimum-latency geolocated image access independent of image size or spatial resolution. The key component in this package is the Meta Raster Format (MRF), a specialized raster file extension to the Geospatial Data Abstraction Library (GDAL) consisting of an internal indexed pyramid of image tiles. Imagery to be served is converted to the MRF format and made accessible online via an expandable set of server modules handling requests in several common protocols, including the Open Geospatial Consortium (OGC) compliant Web Map Tile Service (WMTS) as well as Tiled WMS and Keyhole Markup Language (KML). OnEarth has recently transitioned to open source status and is maintained and actively developed as part of GIBS (Global Imagery Browse Services), a collaborative project between JPL and Goddard Space Flight Center (GSFC). The primary function of GIBS is to enhance and streamline the data discovery process and to support near real-time (NRT) applications via the expeditious ingestion and serving of full-resolution imagery representing science products from across the NASA Earth Science spectrum. Open source software solutions are leveraged where possible in order to utilize existing available technologies, reduce development time, and enlist wider community participation. We will discuss some of the factors and decision points in transitioning OnEarth to a suitable open source paradigm, including repository and licensing agreement decision points, institutional hurdles, and perceived benefits. We will also provide examples illustrating how OnEarth is integrated within GIBS and other applications.

  17. Nonfullerene Tandem Organic Solar Cells with High Open-Circuit Voltage of 1.97 V.

    PubMed

    Liu, Wenqing; Li, Shuixing; Huang, Jiang; Yang, Shida; Chen, Jiehuan; Zuo, Lijian; Shi, Minmin; Zhan, Xiaowei; Li, Chang-Zhi; Chen, Hongzheng

    2016-11-01

    Small-molecule nonfullerene-based tandem organic solar cells (OSCs) are fabricated for the first time by utilizing P3HT:SF(DPPB)4 and PTB7-Th:IEIC bulk heterojunctions as the front and back subcells, respectively. A power conversion efficiency of 8.48% is achieved with an ultrahigh open-circuit voltage of 1.97 V, which is the highest voltage value reported to date among efficient tandem OSCs.

  18. 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).

  19. 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.

  20. Radical covalent organic frameworks: a general strategy to immobilize open-accessible polyradicals for high-performance capacitive energy storage.

    PubMed

    Xu, Fei; Xu, Hong; Chen, Xiong; Wu, Dingcai; Wu, Yang; Liu, Hao; Gu, Cheng; Fu, Ruowen; Jiang, Donglin

    2015-06-01

    Ordered π-columns and open nanochannels found in covalent organic frameworks (COFs) could render them able to store electric energy. However, the synthetic difficulty in achieving redox-active skeletons has thus far restricted their potential for energy storage. A general strategy is presented for converting a conventional COF into an outstanding platform for energy storage through post-synthetic functionalization with organic radicals. The radical frameworks with openly accessible polyradicals immobilized on the pore walls undergo rapid and reversible redox reactions, leading to capacitive energy storage with high capacitance, high-rate kinetics, and robust cycle stability. The results suggest that channel-wall functional engineering with redox-active species will be a facile and versatile strategy to explore COFs for energy storage.

  1. Low-power, open-path mobile sensing platform for high-resolution measurements of greenhouse gases and air pollutants

    NASA Astrophysics Data System (ADS)

    Tao, Lei; Sun, Kang; Miller, David J.; Pan, Dan; Golston, Levi M.; Zondlo, Mark A.

    2015-04-01

    A low-power mobile sensing platform has been developed with multiple open-path gas sensors to measure the ambient concentrations of greenhouse gases and air pollutants with high temporal and spatial resolutions over extensive spatial domains. The sensing system consists of four trace gas sensors including two custom quantum cascade laser-based open-path sensors and two LICOR open-path sensors to measure CO2, CO, CH4, N2O, NH3, and H2O mixing ratios simultaneously at 10 Hz. In addition, sensors for meteorological and geolocation data are incorporated into the system. The system is powered by car batteries with a low total power consumption (~200 W) and is easily transportable due to its low total mass (35 kg). Multiple measures have been taken to ensure robust performance of the custom, open-path sensors located on top of the vehicle where the optics are exposed to the harsh on-road environment. The mobile sensing system has been integrated and installed on top of common passenger vehicles and participated in extensive field campaigns (>400 h on-road time with >18,000 km total distance) in both the USA and China. The simultaneous detection of multiple trace gas species makes the mobile sensing platform a unique and powerful tool to identify and quantify different emission sources through mobile mapping.

  2. Mini-open PLIF for Moderate to High Grade Spondylolisthesis: Technique to Achieve Spontaneous Reduction

    PubMed Central

    Jeong, Se Ho; Kim, Hyeun Sung

    2015-01-01

    Objective The purpose of this study was to evaluate the surgical technique and outcome of mini-open posterior lumbar interbody fusion (PLIF) under circumferential releasing technique. Methods Fourty patients who underwent mini-open PLIF using the percutaneous screw fixation system for Meyerding Grade II spondylolisthesis or more were retrospectively studied. After complete circumferential release, the slipped vertebrae would tend to obtain spontaneous reduction, and with compressive force by percutaneous screw fixation, additional reduction could be achieved. The radiological measurements including slippage reduction, disc height, restoration of lumbar lordotic angle and focal segmental angle were analyzed. The clinical outcome was assessed using the visual analog scale (VAS) and low back outcome score (LBOS), and procedure related complications were also analyzed. Results Slippage percentage was improved from 38.0±12.6% to 9.3±7.8% and lumbar lordotic angle was changed from 43.0±13.8° to 48.2±10.3°. Focal segmental angle improved from 10.1±8.5° to 15.9±6.0°. The mean LBOS and mean pain score were also improved significantly. Complications included one case of medial penetration of pedicle border and two cases of transient radiculopathy. However, there were no signs of neurological aggravation or fusion failure during the follow-up period. Conclusion Mini-open PLIF using the percutaneous screw fixation following complete circumferential release can be safe and effective treatment for even moderate to severe grade spondylolisthesis. PMID:26834812

  3. DasPy – Open Source Multivariate Land Data Assimilation Framework with High Performance Computing

    NASA Astrophysics Data System (ADS)

    Han, Xujun; Li, Xin; Montzka, Carsten; Kollet, Stefan; Vereecken, Harry; Hendricks Franssen, Harrie-Jan

    2015-04-01

    Data assimilation has become a popular method to integrate observations from multiple sources with land surface models to improve predictions of the water and energy cycles of the soil-vegetation-atmosphere continuum. In recent years, several land data assimilation systems have been developed in different research agencies. Because of the software availability or adaptability, these systems are not easy to apply for the purpose of multivariate land data assimilation research. Multivariate data assimilation refers to the simultaneous assimilation of observation data for multiple model state variables into a simulation model. Our main motivation was to develop an open source multivariate land data assimilation framework (DasPy) which is implemented using the Python script language mixed with C++ and Fortran language. This system has been evaluated in several soil moisture, L-band brightness temperature and land surface temperature assimilation studies. The implementation allows also parameter estimation (soil properties and/or leaf area index) on the basis of the joint state and parameter estimation approach. LETKF (Local Ensemble Transform Kalman Filter) is implemented as the main data assimilation algorithm, and uncertainties in the data assimilation can be represented by perturbed atmospheric forcings, perturbed soil and vegetation properties and model initial conditions. The CLM4.5 (Community Land Model) was integrated as the model operator. The CMEM (Community Microwave Emission Modelling Platform), COSMIC (COsmic-ray Soil Moisture Interaction Code) and the two source formulation were integrated as observation operators for assimilation of L-band passive microwave, cosmic-ray soil moisture probe and land surface temperature measurements, respectively. DasPy is parallelized using the hybrid MPI (Message Passing Interface) and OpenMP (Open Multi-Processing) techniques. All the input and output data flow is organized efficiently using the commonly used NetCDF file

  4. High rate, long cycle life battery electrode materials with an open framework structure

    DOEpatents

    Wessells, Colin; Huggins, Robert; Cui, Yi; Pasta, Mauro

    2015-02-10

    A battery includes a cathode, an anode, and an aqueous electrolyte disposed between the cathode and the anode and including a cation A. At least one of the cathode and the anode includes an electrode material having an open framework crystal structure into which the cation A is reversibly inserted during operation of the battery. The battery has a reference specific capacity when cycled at a reference rate, and at least 75% of the reference specific capacity is retained when the battery is cycled at 10 times the reference rate.

  5. Opening Wedge Osteotomy for Distal Radius Malunion: Dorsal or Palmar Approach?

    PubMed Central

    Rothenfluh, Esin; Schweizer, Andreas; Nagy, Ladislav

    2013-01-01

    Background There are various technical variations to consider when performing a corrective osteotomy of a distal radius malunion. We chose two of the more commonly reported techniques and compared the results of volar (palmar) osteotomy and fixation with dorsal osteotomy and fixation. Method Within a continuous cohort of patients who had undergone corrective osteotomy for a malunited Colles fracture, two groups could be identified retrospectively. In 8 patients a dorsal approach was used. A structural trapezoidal graft, subtending the amount of correction, was inserted into the osteotomy gap and stabilization was performed with a thin round-hole mini-fragment plate. In 14 patients a palmar approach and a palmar fixed-angle plate was used for correction of the malunion and for angular stable rigid fixation of the two fragments. The osteotomy gap was loosely filled with nonstructural cancellous bone chips. A retrospective comparison of the two groups was performed to see whether the outcome was affected by the use of either operative technique.The demographics, the preoperative amount of deformity, range of motion, pain, and force were comparable for both groups. All osteotomies healed without loss of correction. After a minimal follow-up of one year, radiographic appearance, objective functional parameters were assessed and subjective data (Disabilities of the Arm, Shoulder, and Hand [DASH] score and special pain and function questionnaire) obtained. Results These data did not show statistical difference for the two groups except for the amount of final wrist flexion. This parameter was significantly better in patients who had palmar approaches and fixed-angle plates. Conclusion Corrective osteotomies of distal radius malunions can be done in either way. It might result in some better flexion, if performed volarly. PMID:24436789

  6. Lithium Isotope Study of Peridotite-Slab Fluid Interactions in the Mariana Forearc Mantle Wedge

    NASA Astrophysics Data System (ADS)

    Lui-Heung, C.; Savov, I. P.; Ryan, J. G.

    2006-05-01

    Drilling of the Mariana forearc region during ODP Leg 195 at S. Chamorro Seamount recovered serpentinized peridotite clasts enclosed by serpentinite muds and slab-derived porefluids. In the serpentinized peridotite clasts the ranges of Li abundance (1- 8 ppm) and δ7Li (-1.4 to +5 ‰) are similar to those reported for the forearc- serpentinites of the Conical Seamount [Benton et al., 2004]. Although the serpentinized muds show Li abundances comparable to the clasts (0.5- 10 ppm; average: 2.5 ppm), they have higher δ7Li (+13.4 ‰). Heavier isotopic composition of serpentinized muds confirms the inferences from REE modeling and the visual observations for the presence of 5-10 % metabasalt component, most probably from the Pacific oceanic crust. Fluids (pH up to 12.5) circulating within the muds are highly depleted in Li and show dramatic 7Li-enrichment relative to seawater (δ7Li up to 47 per mil). These characteristics are consistent with near complete removal of Li from slab fluids into minerals of the sepentinite assemblage. We will present a model to describe the fluid-rock interaction including a reconstruction of the Li isotope compositions of the fluids as they leave the subducted slab assemblage, before transiting through the Mariana mantle wedge. Our model will evaluate the importance of Raleigh- type distillation processes under high P/low T conditions within the sub-arc mantle. Because both Conical and S.Chamorro seamounts are sampling approx. 30 km deep column of similarly depleted mantle wedge immediately above the subducting Pacific plate, the clasts may have similar Li systematics due to the effect of equally long transit through the mantle. The similarity in δ7Li signature among all arc lavas implies that although the ultimate source of Li is the subducting slab, the final Li isotope makeup of arc magmatic suites is controlled by the degree of mantle wedge- fluid/ (melt?) interaction upon emplacement.

  7. Fundamental parameters of the highly reddened young open clusters Westerlund 1 and 2

    NASA Astrophysics Data System (ADS)

    Piatti, A. E.; Bica, E.; Claria, J. J.

    1998-02-01

    We study the compact open clusters Westerlund1 (BH197) and Westerlund2. We present CCD integrated spectroscopy for both clusters, and CCD imaging in the V and I bands for the former one. So far, Westerlund1 is possibly the most reddened open cluster studied in detail (Av ~ 13.0). It has an age of 8 +/- 3 Myr and a distance from the Sun of d_sun ~ 1.0 +/- 0.4 kpc. For Westerlund2 we derive a visual absorption AV~ 5.0 mag, an age of 2-3 Myr, and d_sun=5.7+/- 0.3 kpc. From luminosity and structural arguments we conclude that Westerlund1, although young and compact, it is a massive cluster, in contrast to Westerlund2. Based on observations made at Complejo Astronómico El Leoncito, which is operated under agreement between the Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina and the Universities of La Plata, Cordoba and San Juan, Argentina, and at the University of Toronto (David Dunlap Observatory) 24-inch telescope, Las Campanas, Chile. The photometric observations are available at CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

  8. Investigation of a Wedge Adhesion Test for Edge Seals

    SciTech Connect

    Kempe, Michael; Wohlgemuth, John; Miller, David; Postak, Lori; Booth, Dennis; Phillips, Nancy

    2016-09-26

    Many photovoltaic (PV) technologies have been found to be sensitive to moisture that diffuses into a PV package. Even with the use of impermeable frontsheets and backsheets, moisture can penetrate from the edges of a module. To limit this moisture ingress pathway from occurring, manufacturers often use a low permeability polyisobutylene (PIB) based edge seal filled with desiccant to further restrict moisture ingress. Moisture ingress studies have shown that these materials are capable of blocking moisture for the 25-year life of a module; but to do so, they must remain well-adhered and free of cracks. This work focuses on adapting the Boeing Wedge test for use with edge seals laminated using glass substrates as part of a strategy to assess the long-term durability of edge seals. The advantage of this method is that it duplicates the residual stresses and strains that a glass/glass module may have when the lamination process results in some residual glass bending that puts the perimeter in tension. Additionally, this method allows one to simultaneously expose the material to thermal stress, humidity, mechanical stress, and ultraviolet radiation. The disadvantage of this method generally is that we are limited by the fracture toughness of the glass substrates that the edge seal is adhered to. However, the low toughness of typical uncrosslinked or sparsely crosslinked PIB makes them suitable for this technique. We present data obtained during the development of the wedge test for use with PV edge seal materials. This includes development of the measuring techniques and evaluation of the test method with relevant materials. We find consistent data within a given experiment, along with the theoretical independence of fracture toughness measurements with wedge thickness. This indicates that the test methodology is reproducible. However, even though individual experimental sets are consistent, the reproducibility between experimental sets is poor. We believe this may be

  9. Investigation of a wedge adhesion test for edge seals

    NASA Astrophysics Data System (ADS)

    Kempe, Michael; Wohlgemuth, John; Miller, David; Postak, Lori; Booth, Dennis; Phillips, Nancy

    2016-09-01

    Many photovoltaic (PV) technologies have been found to be sensitive to moisture that diffuses into a PV package. Even with the use of impermeable frontsheets and backsheets, moisture can penetrate from the edges of a module. To limit this moisture ingress pathway from occurring, manufacturers often use a low permeability polyisobutylene (PIB) based edge seal filled with desiccant to further restrict moisture ingress. Moisture ingress studies have shown that these materials are capable of blocking moisture for the 25-year life of a module; but to do so, they must remain well-adhered and free of cracks. This work focuses on adapting the Boeing Wedge test for use with edge seals laminated using glass substrates as part of a strategy to assess the long-term durability of edge seals. The advantage of this method is that it duplicates the residual stresses and strains that a glass/glass module may have when the lamination process results in some residual glass bending that puts the perimeter in tension. Additionally, this method allows one to simultaneously expose the material to thermal stress, humidity, mechanical stress, and ultraviolet radiation. The disadvantage of this method generally is that we are limited by the fracture toughness of the glass substrates that the edge seal is adhered to. However, the low toughness of typical uncrosslinked or sparsely crosslinked PIB makes them suitable for this technique. We present data obtained during the development of the wedge test for use with PV edge seal materials. This includes development of the measuring techniques and evaluation of the test method with relevant materials. We find consistent data within a given experiment, along with the theoretical independence of fracture toughness measurements with wedge thickness. This indicates that the test methodology is reproducible. However, even though individual experimental sets are consistent, the reproducibility between experimental sets is poor. We believe this may be

  10. Medical devices; obstetrical and gynecological devices; classification of the hemorrhoid prevention pressure wedge. Final rule.

    PubMed

    2011-04-15

    The Food and Drug Administration (FDA) is classifying the hemorrhoid prevention pressure wedge into class II (special controls). The special controls will apply to the device in order to provide a reasonable assurance of safety and effectiveness of the device. A hemorrhoid prevention pressure wedge provides support to the perianal region during the labor and delivery process.

  11. A quantum hybrid with a thin antenna at the vertex of a wedge

    NASA Astrophysics Data System (ADS)

    Carlone, Raffaele; Posilicano, Andrea

    2017-03-01

    We study the spectrum, resonances and scattering matrix of a quantum Hamiltonian on a "hybrid surface" consisting of a half-line attached by its endpoint to the vertex of a concave planar wedge. At the boundary of the wedge, outside the vertex, homogeneous Dirichlet conditions are imposed. The system is tunable by varying the measure of the angle at the vertex.

  12. 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.

  13. [Electron microscopic study of wedge-shaped defects of teeth on initial stage].

    PubMed

    Makeeva, I M; Biakova, S F; Chuev, V P; Sheveliuk, Iu V

    2009-01-01

    The aim of thes; study was to observe initial stage of wedge-shaped defects under scanning electron microscopy without prior samples preparation. There were revealed special features of structure of enamel and cement at initial stage of wedge-shaped defects in comparison to normal tissues.

  14. Reflection of a converging cylindrical shock wave segment by a straight wedge

    NASA Astrophysics Data System (ADS)

    Gray, B.; Skews, B.

    2017-01-01

    As a converging cylindrical shock wave propagates over a wedge, the shock wave accelerates and the angle between the shock wave and the wedge decreases. This causes the conditions at the reflection point to move from what would be the irregular reflection domain for a straight shock wave into the regular reflection domain. This paper covers a largely qualitative study of the reflection of converging shock wave segments with Mach numbers between 1.2 and 2.1 by wedges inclined at angles between 15° and 60° from experimental and numerical results. The sonic condition conventionally used for predicting the type of reflection of straight shock waves was found to also be suitable for predicting the initial reflection of a curved shock wave. Initially regular reflections persisted until the shock was completely reflected by the wedge, whereas the triple point of initially irregular reflections was observed to return to the wedge surface, forming transitioned regular reflection. After the incident shock wave was completely reflected by the wedge, a shock wave focusing mechanism was observed to amplify the pressure on the surface of the wedge by a factor of up to 100 for low wedge angles.

  15. Highly Selective Adsorption of Ethylene over Ethane in a MOF Featuring the Combination of Open Metal Site and -Complexation

    SciTech Connect

    Zhang, Yiming; Li, Baiyan; Wu, Zili; Ma, Shengqian

    2015-01-01

    The introduction of the combination of open metal site (OMS) and -complexation into MOF has led to very high ethylene/ethane adsorption selectivity at 318K, as illustrated in the context of MIL-101-Cr-SO3Ag. The interactions with ethylene from both OMS and -complexation in MIL-101-Cr-SO3Ag have been investigated by in situ IR spectroscopic studies and computational calculations, which suggest -complexation contributes dominantly to the high ethylene/ethane adsorption selectivity.

  16. An Azulene-Containing Low Bandgap Small Molecule for Organic Photovoltaics with High Open-Circuit Voltage.

    PubMed

    Chen, Yao; Zhu, Youqin; Yang, Daobin; Zhao, Suling; Zhang, Lei; Yang, Lin; Wu, Jianglin; Huang, Yan; Xu, Zheng; Lu, Zhiyun

    2016-10-04

    A simple azulene-containing squaraine dye (AzUSQ) showing bandgap of 1.38 eV and hole mobility up to 1.25×10(-4)  cm(2)  V(-1)  s(-1) was synthesized. With its low bandgap, an organic photovoltaic (OPV) device based on it has been made that exhibits an impressive open-circuit voltages (Voc ) of 0.80 V. Hence, azulene might be a promising structural unit to construct OPV materials with simultaneous low bandgap, high hole mobility and high Voc .

  17. Open source large-scale high-resolution environmental modelling with GEMS

    NASA Astrophysics Data System (ADS)

    Baarsma, Rein; Alberti, Koko; Marra, Wouter; Karssenberg, Derek

    2016-04-01

    Many environmental, topographic and climate data sets are freely available at a global scale, creating the opportunities to run environmental models for every location on Earth. Collection of the data necessary to do this and the consequent conversion into a useful format is very demanding however, not to mention the computational demand of a model itself. We developed GEMS (Global Environmental Modelling System), an online application to run environmental models on various scales directly in your browser and share the results with other researchers. GEMS is open-source and uses open-source platforms including Flask, Leaflet, GDAL, MapServer and the PCRaster-Python modelling framework to process spatio-temporal models in real time. With GEMS, users can write, run, and visualize the results of dynamic PCRaster-Python models in a browser. GEMS uses freely available global data to feed the models, and automatically converts the data to the relevant model extent and data format. Currently available data includes the SRTM elevation model, a selection of monthly vegetation data from MODIS, land use classifications from GlobCover, historical climate data from WorldClim, HWSD soil information from WorldGrids, population density from SEDAC and near real-time weather forecasts, most with a ±100m resolution. Furthermore, users can add other or their own datasets using a web coverage service or a custom data provider script. With easy access to a wide range of base datasets and without the data preparation that is usually necessary to run environmental models, building and running a model becomes a matter hours. Furthermore, it is easy to share the resulting maps, timeseries data or model scenarios with other researchers through a web mapping service (WMS). GEMS can be used to provide open access to model results. Additionally, environmental models in GEMS can be employed by users with no extensive experience with writing code, which is for example valuable for using models

  18. 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

  19. Distortion of optical wedges with a large angle of incidence in a collimated beam

    NASA Astrophysics Data System (ADS)

    Mao, Wenwei; Xu, Yuxian

    1999-04-01

    The optical wedge engenders a distortion aberration in a collimated beam in general. Presented is a set of distortion formulas and of third-order distortion formulas in the component form of TAx and TAy for optical wedges. The main dependence of the distortion as a function of the apex angle, of the incident angle of the optical axis, and of the view field of the optical wedge is established. The slope formula of a curved line, which is the image of a straight line of an optical wedge, is developed. They are suited for the large incident angle of the optical axis and the small apex angle. The analysis and calculation indicate that the image of a square for an optical wedge is in the shape of a church bell with a slightly convex or flat side rather than with a concave side.

  20. 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.

  1. The accuracy of transoesophageal echocardiography in estimating pulmonary capillary wedge pressure in anaesthetised patients.

    PubMed

    Ali, M M; Royse, A G; Connelly, K; Royse, C F

    2012-02-01

    The objective of this study was to identify whether pulmonary capillary wedge pressure can be estimated in anaesthetised patients receiving mechanical ventilation, using transoesophageal echocardiography. A retrospective validation study investigated a 10-patient cohort with variable haemodynamic conditions, and a 102-patient series in which a single measurement was made during stable haemodynamic conditions. Concurrent echocardiographic Doppler and pulmonary artery catheter wedge pressure measurements were performed. In the 10-patient cohort, the systolic fraction of Doppler measurements in the pulmonary vein (r = -0.32, p = 0.035) and the E/A ratio (r = 0.56, p = 0.0009) were correlated with the wedge pressure. In all cases, the limits of agreement exceeded 10 mmHg, and sensitivity or specificity for detecting wedge pressure ≥ 15 mmHg was poor. This study demonstrates proof of concept that using transoesophageal echocardiography for estimating the pulmonary artery wedge pressure may not be sufficiently accurate for clinical use.

  2. Simple phase-shifting method in a wedge-plate lateral-shearing interferometer.

    PubMed

    Song, Jae Bong; Lee, Yun Woo; Lee, In Won; Lee, Yong-Hee

    2004-07-10

    A simple phase-shifting method in a wedge-plate lateral shearing interferometer is described. Simply moving the wedge plate in an in-plane parallel direction gives the amount of phase shift required for phase-shifting interferometry because the thickness of a wedge plate is not constant and varies along the wedge direction. This method requires only one additional linear translator to move the wedge plate. The required moving distance for a phase shift of the wave front with this method is of the order of a millimeter, whereas the typical moving distance for another method that uses a piezoelectric transducer is of the order of a wavelength. This method yields better precision in controlling the moving distance than do the other methods.

  3. 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.

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

    SciTech Connect

    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.

  5. 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.

  6. [Diversity of bacterial forms in ice wedge of the Mamontova Gora Glacial complex (central Yakutiya)].

    PubMed

    Filippova, S N; Surgucheva, N A; Sorokin, V V; Cherbunina, M Iu; Karnysheva, E A; Brushkov, A V; Gal'chenko, V F

    2014-01-01

    Electron microscopic investigation of four samples of ancient ice wedge from the Pleistocene glacial complex of Mamontova Gora (Yakutiya, Russia) revealed high diversity of bacteriomorphic particles. Their structural features included the presence of electron-transparent zones, presumably inclusions containing storage compounds, and microenvironment (capsules or external sheaths). These features may be a result of adaptive strategies providing for microbial survival under permafrost conditions. Predominance of rod-shaped forms morphologically resembling coryneform actinobacteria was found. X-ray microanalysis revealed organic origin of bacteriomorphic particles. Some particles were characterized by incomplete spectra of the major biogenic elements, resulting probably from low-temperature damage to the cellular structures. Total numbers of aerobic heterotrophic bacteria determined by plating on nutrient media were comparable to the values obtained for permafrost soils and Arctic ice. Predominance of coryneform actinobacteria was observed. Abundance of these evolutionarily early groups of actinobacteria may indicate the ancient origin of the microflora of the relic frozen rocks.

  7. Mosaic wedge-and-strip arrays for large format microchannel plate detectors

    NASA Technical Reports Server (NTRS)

    Martin, Christopher; Rasmussen, Andrew

    1989-01-01

    The authors present a novel method for joining wedge-and-strip patterns on single anodes in a mosaic array. With only a modest increase in complexity over three-conductor anodes currently in use, the ultimate detector position resolution can be significantly improved, and large-format microchannel plate detectors with pore-size-limited resolution are made possible. The problem of the transition from one anode to the next has been solved with a novel linear encoding scheme, which exhibits essentially distortionless behavior at boundaries parallel to the conducting elements and only slight distortion at the orthogonal boundaries. The ultimate resolution for two anode designs, one designed for large-format imaging and the other for high-resolution spectroscopy, is also predicted.

  8. Tubulation by amphiphysin requires concentration-dependent switching from wedging to scaffolding

    PubMed Central

    Isas, J. Mario; Ambroso, Mark R.; Hegde, Prabhavati B.; Langen, Jennifer; Langen, Ralf

    2015-01-01

    Summary BAR proteins are involved in a variety of membrane remodeling events, but how they can mold membranes into different shapes remains poorly understood. Using EPR, we find that vesicle binding of the N-BAR protein amphiphysin is predominantly mediated by the shallow insertion of amphipathic N-terminal helices. In contrast, the interaction with tubes involves deeply inserted N-terminal helices together with the concave surface of the BAR domain, which acts as a scaffold. Combined with the observed concentration dependence of tubulation and BAR domain scaffolding, the data indicate that initial membrane deformations and vesicle binding are mediated by insertion of amphipathic helical wedges, while tubulation requires high protein densities at which oligomeric BAR domain scaffolds form. In addition, we identify a pocket of residues on the concave surface of the BAR domain that deeply insert into tube membrane. Interestingly, this pocket harbors a number of disease mutants in the homologous amphiphysin 2. PMID:25865245

  9. 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.

  10. 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.

  11. Design of a high order Campbelling mode measurement system using open source hardware

    NASA Astrophysics Data System (ADS)

    Izarra, G. de; Elter, Zs.; Jammes, C.

    2016-12-01

    This paper reviews a new real-time measurement instrument dedicated for online neutron monitoring with fission chambers in nuclear reactors. The instrument implements the higher order Campbelling methods and self-monitoring capabilities on an open source development board. The board includes an CPU/FPGA System on a Chip. The feasibility of the measurement instrument was tested both in laboratory with a signal generator and in the Minerve reactor. It is shown that the instrument provides reliable and robust count rate estimation over a wide reactor power range based on the third order statistics of the fission chamber signal. In addition, the system is able to identify whether the measured count rate change is due to the malfunction of the detector or due to the change in the neutron flux. The applied self-monitoring method is based on the spectral properties of the fission chamber signal. During the experimental verification, the considered malfunction was the change of the polarization voltage.

  12. 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

  13. Local Atmospheric Response to an Open-Ocean Polynya in a High-Resolution Climate Model

    DOE PAGES

    Weijer, Wilbert; Veneziani, Milena; Stössel, Achim; ...

    2017-03-01

    For this scientific paper, we study the atmospheric response to an open-ocean polynya in the Southern Ocean by analyzing the results from an atmospheric and oceanic synoptic-scale resolving Community Earth System Model (CESM) simulation. While coarser-resolution versions of CESM generally do not produce open-ocean polynyas in the Southern Ocean, they do emerge and disappear on interannual timescales in the synoptic-scale simulation. This provides an ideal opportunity to study the polynya’s impact on the overlying and surrounding atmosphere. This has been pursued here by investigating the seasonal cycle of differences of surface and air-column variables between polynya and non-polynya years. Ourmore » results indicate significant local impacts on turbulent heat fluxes, precipitation, cloud characteristics, and radiative fluxes. In particular, we find that clouds over polynyas are optically thicker and higher than clouds over sea ice during non-polynya years. Although the lower albedo of polynyas significantly increases the net shortwave absorption, the enhanced cloud brightness tempers this increase by almost 50%. Also, in this model, enhanced longwave radiation emitted from the warmer surface of polynyas is balanced by stronger downwelling fluxes from the thicker cloud deck. Impacts are found to be sensitive to the synoptic wind direction. Strongest regional impacts are found when northeasterly winds cross the polynya and interact with katabatic winds. Finally, surface air pressure anomalies over the polynya are only found to be significant when cold, dry air masses strike over the polynya, i.e. in case of southerly winds.« less

  14. Local atmospheric response to an open-ocean polynya in a high-resolution climate model

    DOE PAGES

    Weijer, Wilbert; Veneziani, Milena; Stössel, Achim; ...

    2017-02-14

    In this paper we study the atmospheric response to an open-ocean polynya in the Southern Ocean by analyzing the results from an atmospheric and oceanic synoptic-scale resolving Community Earth System Model (CESM) simulation. While coarser-resolution versions of CESM generally do not produce open-ocean polynyas in the Southern Ocean, they do emerge and disappear on interannual timescales in the synoptic-scale simulation. This provides an ideal opportunity to study the polynya’s impact on the overlying and surrounding atmosphere. This has been pursued here by investigating the seasonal cycle of differences of surface and air-column variables between polynya and nonpolynya years. Our resultsmore » indicate significant local impacts on turbulent heat fluxes, precipitation, cloud characteristics, and radiative fluxes. In particular, we find that clouds over polynyas are optically thicker and higher than clouds over sea ice during non-polynya years. Although the lower albedo of polynyas significantly increases the net shortwave absorption, the enhanced cloud brightness tempers this increase by almost 50%. Also, in this model, enhanced longwave radiation emitted from the warmer surface of polynyas is balanced by stronger downwelling fluxes from the thicker cloud deck. Impacts are found to be sensitive to the synoptic wind direction. Strongest regional impacts are found when northeasterly winds cross the polynya and interact with katabatic winds. As a result, surface air pressure anomalies over the polynya are only found to be significant when cold, dry air masses strike over the polynya, i.e. in case of southerly winds.« less

  15. Local atmospheric response to an open-ocean polynya in a high-resolution climate model

    SciTech Connect

    Weijer, Wilbert; Veneziani, Milena; Stössel, Achim; Hecht, Matthew W.; Jeffery, Nicole; Jonko, Alexandra; Hodos, Travis; Wang, Hailong

    2016-11-17

    For this scientific paper, we study the atmospheric response to an open-ocean polynya in the Southern Ocean by analyzing the results from an atmospheric and oceanic synoptic-scale resolving Community Earth System Model (CESM) simulation. While coarser-resolution versions of CESM generally do not produce open-ocean polynyas in the Southern Ocean, they do emerge and disappear on interannual timescales in the synoptic-scale simulation. This provides an ideal opportunity to study the polynya’s impact on the overlying and surrounding atmosphere. This has been pursued here by investigating the seasonal cycle of differences of surface and air-column variables between polynya and non-polynya years. Our results indicate significant local impacts on turbulent heat fluxes, precipitation, cloud characteristics, and radiative fluxes. In particular, we find that clouds over polynyas are optically thicker and higher than clouds over sea ice during non-polynya years. Although the lower albedo of polynyas significantly increases the net shortwave absorption, the enhanced cloud brightness tempers this increase by almost 50%. Also, in this model, enhanced longwave radiation emitted from the warmer surface of polynyas is balanced by stronger downwelling fluxes from the thicker cloud deck. Impacts are found to be sensitive to the synoptic wind direction. Strongest regional impacts are found when northeasterly winds cross the polynya and interact with katabatic winds. Finally, surface air pressure anomalies over the polynya are only found to be significant when cold, dry air masses strike over the polynya, i.e. in case of southerly winds.

  16. 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.

  17. Experiments on melt-rock reaction in the shallow mantle wedge

    NASA Astrophysics Data System (ADS)

    Mitchell, Alexandra L.; Grove, Timothy L.

    2016-12-01

    This experimental study simulates the interaction of hotter, deeper hydrous mantle melts with shallower, cooler depleted mantle, a process that is expected to occur in the upper part of the mantle wedge. Hydrous reaction experiments ( 6 wt% H2O in the melt) were conducted on three different ratios of a 1.6 GPa mantle melt and an overlying 1.2 GPa harzburgite from 1060 to 1260 °C. Reaction coefficients were calculated for each experiment to determine the effect of temperature and starting bulk composition on final melt compositions and crystallizing assemblages. The experiments used to construct the melt-wall rock model closely approached equilibrium and experienced <5% Fe loss or gain. Experiments that experienced higher extents of Fe loss were used to critically evaluate the practice of "correcting" for Fe loss by adding iron. At low ratios of melt/mantle (20:80 and 5:95), the crystallizing assemblages are dunites, harzburgites, and lherzolites (as a function of temperature). When the ratio of deeper melt to overlying mantle is 70:30, the crystallizing assemblage is a wehrlite. This shows that wehrlites, which are observed in ophiolites and mantle xenoliths, can be formed by large amounts of deeper melt fluxing though the mantle wedge during ascent. In all cases, orthopyroxene dissolves in the melt, and olivine crystallizes along with pyroxenes and spinel. The amount of reaction between deeper melts and overlying mantle, simulated here by the three starting compositions, imposes a strong influence on final melt compositions, particularly in terms of depletion. At the lowest melt/mantle ratios, the resulting melt is an extremely depleted Al-poor, high-Si andesite. As the fraction of melt to mantle increases, final melts resemble primitive basaltic andesites found in arcs globally. An important element ratio in mantle lherzolite composition, the Ca/Al ratio, can be significantly elevated through shallow mantle melt-wall rock reaction. Wall rock temperature is a key

  18. 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

  19. Opening Doors to Postsecondary Education and Training: Planning for Life after High School.

    ERIC Educational Resources Information Center

    Wisconsin State Dept. of Public Instruction, Madison.

    This handbook is designed as a guide to help students with disabilities take another step in preparing for "life after high school." While high school is an exciting time, what you do after high school can be just as exciting if you have done some careful and thoughtful planning. Students'"Transition Plans" include: thinking about their strengths…

  20. 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.

  1. THE USE OF SINGULAR INTEGRALS IN WAVE DIFFRACTION PROBLEMS WITH THE SOLUTION OF THE PROBLEM OF SCATTERING BY A DIELECTRIC WEDGE,

    DTIC Science & Technology

    ELECTROMAGNETIC RADIATION, DIFFRACTION, WEDGES, WEDGES, PRISMATIC BODIES, COMPLEX VARIABLES , PRISMS(OPTICS), REFRACTION, FUNCTIONS(MATHEMATICS), REFLECTION, PARTIAL DIFFERENTIAL EQUATIONS, SCATTERING.

  2. 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

  3. 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

  4. 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

  5. High Performance Open Loop Control of Scanning with a Small Cylindrical Cantilever Beam.

    PubMed

    Kundrat, Matthew J; Reinhall, Per G; Lee, Cameron M; Seibel, Eric J

    2011-04-11

    The steady state response motion of a base excited cantilever beam with circular cross-section excited by a unidirectional displacement will fall along a straight line. However, achieving straight-line motion with a real cantilever beam of circular cross-section is difficult to accomplish. This is due to the fact that nonlinear effects, small deviations from circularity, asymmetric boundary conditions, and actuator cross coupling can induce whirling. The vast majority of previous work on cantilever beam whirling has focused on the effects of system nonlinearities. We show that whirling is a much broader problem in the design of resonant beam scanners in that the onset of whirling does not depend on large amplitude of motion. Rather, whirling is the norm in real systems due to small system asymmetries and actuator cross coupling. It is therefore necessary to control the growth of the whirling motion when a unidirectional beam motion is desired. We have developed a novel technique to identify the two eigen directions of the beam. Base excitation generated by virtual electrodes along these orthogonal eigen axes of the cantilever beam system generates tip vibration without whirl. This leads to accurate open loop control of the motion of the beam through the combined actuation of two pairs of orthogonally placed actuator electrodes.

  6. High-resolution elemental abundance analysis of the open cluster IC 4756

    NASA Astrophysics Data System (ADS)

    Ting, Yuan-Sen; De Silva, Gayandhi M.; Freeman, Kenneth C.; Parker, Stacey Jo

    2012-11-01

    We present detailed elemental abundances of 12 subgiants in the open cluster IC 4756 including Na, Al, Mg, Si, Ca, Ti, Cr, Ni, Fe, Zn and Ba. We measure the cluster to have [Fe/H] = -0.01 ± 0.10. Most of the measured star-to-star [X/H] abundance variation is below σ < 0.03, as expected from a coeval stellar population preserving natal abundance patterns, supporting the use of elemental abundances as a probe to reconstruct dispersed clusters. We find discrepancies between Cr I and Cr II abundances as well as between Ti I and Ti II abundances, where the ionized abundances are larger by about 0.2 dex. This follows other such studies which demonstrate the effects of overionization in cool stars. IC 4756 are supersolar in Mg, Si, Na and Al, but are solar in the other elements. The fact that IC 4756 is supersolar in some α-elements (Mg, Si) but solar in the others (Ca, Ti) suggests that the production of α-elements is not simply one dimensional and could be exploited for chemical tagging.

  7. High activity of an indium alkoxide complex toward ring opening polymerization of cyclic esters.

    PubMed

    Quan, Stephanie M; Diaconescu, Paula L

    2015-06-14

    An indium complex supported by a ferrocene-derived Schiff base ligand has an unprecedented high activity toward ε-caprolactone, δ-valerolactone, and β-butyrolactone. l-Lactide, d,l-lactide, and trimethylene carbonate polymerizations also showed moderate to high activity.

  8. Opening the Doors a Little Wider: High School Students Attending Junior Colleges.

    ERIC Educational Resources Information Center

    Schrupp, Harold A.

    Through the Veysey and the Regional Occupation Program/Regional Occupation Center (ROP/ROC) Acts, junior colleges can assist high school students in gaining skills for immediate employment on high school graduation. In an attempt to develop an early introduction to technical skills, the Veysey Act (initial legislation 1963; amended 1967) allows…

  9. Thrust-related, diapiric, and extensional doming in a frontal orogenic wedge: example of the Montagne Noire, Southern French Hercynian Belt

    NASA Astrophysics Data System (ADS)

    Soula, Jean-Claude; Debat, Pierre; Brusset, Stéphane; Bessière, Gilbert; Christophoul, Frédéric; Déramond, Joachim

    2001-11-01

    The Montagne Noire, which is situated at the toe of the orogenic wedge of the French Massif Central South European Variscides, appears to be a well-suited area for studying the origin and evolution of middle to upper crustal domes adjacent to foreland basins. The data reported in the present paper show that the Montagne Noire dome is a particular type of basement-involved frontal culmination in an orogenic wedge and foreland basin system. This frontal culmination is characterized by a syn-contractional HT decompression recorded by clockwise PTt paths and widespread strata overturning in thrust and fold structures, which controlled the sedimentation in the adjacent foreland basin. These unusual characteristics are interpreted to be a result of the succession of thrusting, diapirism and extensional collapse. Antiformal stacking of syn-metamorphic thrust sheets controlled the first stages of the foreland basin development. Diapirism was essentially responsible for the HT decompression and widespread strata overturning. Extensional doming was a result of late- to post-metamorphic collapse acting on the pre-existing high-amplitude dome. Diapirism and associated isothermal decompression metamorphism, which constitute the essential difference between the Montagne Noire and 'ordinary' frontal ridges in orogenic wedges, were probably enhanced by a local partial melting of the upper to middle crust. It is suggested that the occurrence of these phenomena in front of an orogenic wedge was related to local over-thickening due to the superposition of an upper crustal antiformal stack on top of a lower crustal ramp anticline.

  10. 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.

  11. 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

  12. Automatic monitoring system for high-steep slope in open-pit mine based on GPS and data analysis

    NASA Astrophysics Data System (ADS)

    Zhou, Chunmei; Li, Xianfu; Qin, Sunwei; Qiu, Dandan; Wu, Yanlin; Xiao, Yun; Zhou, Jian

    2008-12-01

    Recently, GPS has been more and more applicative in open pit mine slope safety monitoring. Daye Iron Mine open pit high-steep slope automatic monitoring system mainly consists of three modules, namely, GPS data processing module, monitoring and warning module, emergency plans module. According to the rock mass structural feature and the side slope stability evaluation, it is arranged altogether to seven GPS distortion monitoring points on the sharp of Fault F9 at Daye iron Mine, adopted the combination of monofrequent static GPS receiver and data-transmission radio to carry on the observation, the data processing mainly uses three transect interpolation method to solve the questions of discontinuity and Effectiveness in the data succession. According to the displacement monitoring data from 1990 to 1996 of Daye Iron Mine East Open Pit Shizi mountain Landslide A2, researching the displacement criterion, rate criterion, acceleration criterion, creep curve tangent angle criterion etc of landslide failure, the result shows that the landslide A2 is the lapse type crag nature landslide whose movement in three phases, namely creep stage, accelerated phase, destruction stage. It is different of the failure criterion in different stages and different position that is at the rear, central, front margin of the landslide. It has important guiding significance to put forward the comprehensive failure criterion of seven new-settled monitoring points combining the slope deformation destruction and macroscopic evidence.

  13. Investigation on Twisting and Side Wall Opening Occurring in Curved Hat Channel Products Made of High Strength Steel Sheets

    NASA Astrophysics Data System (ADS)

    Takamura, Masato; Fukui, Ayako; Yano, Hiroshi; Hama, Takayuki; Sunaga, Hideyuki; Makinouchi, Akitake; Asakawa, Motoo

    2011-08-01

    High strength steel sheets are becoming increasingly important for the weight reduction of automotive bodies to meet the requirements for reduced environmental impact. However, dimensional defects resulting from springback are serious issues, and effective methods of predicting and reducing such defects are necessary. In this study, we numerically and experimentally analyzed the mechanisms of dimensional inaccuracies caused by springback occurring in curved hat channel deep drawing products. The analysis was based on the static explicit FEM software "TP-STRUCT" (the solver part is known as "STAMP3D"). The results of the experiments and simulations similarly show that the twist angle is positive (right-hand system) when the drawing height is relatively large. We calculated the twist torque around the longitudinal axis using the stress distributions obtained by FE analysis. Through the investigation of twist torque and its transition during the drawing and die removal processes, we found that the negative torque generated by side wall opening occurring in the die removal process is the dominant factor of the positive twist. Knowing such mechanisms of twist in cases with a relatively large drawing height, we attempted to explore methods of reducing side wall opening by giving the side wall a stepped shape with the eventual aim of reducing twist. Consequently, we concluded that the stepped shape on the side wall has marked effects of reducing side wall opening, mainly through the elimination of bending-unbending effects on die shoulders, which was verified by observing the stress distribution obtained by FE analysis.

  14. 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).

  15. Properties of the Open Cluster Tombaugh 1 from High-resolution Spectroscopy and uvbyCaHβ Photometry

    NASA Astrophysics Data System (ADS)

    Sales Silva, João V.; Carraro, Giovanni; Anthony-Twarog, Barbara J.; Moni Bidin, Christian; Costa, Edgardo; Twarog, Bruce A.

    2016-01-01

    Open clusters can be the key to deepening our knowledge on various issues involving the structure and evolution of the Galactic disk and details of stellar evolution because a cluster’s properties are applicable to all its members. However, the number of open clusters with detailed analysis from high-resolution spectroscopy or precision photometry imposes severe limitations on studies of these objects. To expand the number of open clusters with well-defined chemical abundances and fundamental parameters, we investigate the poorly studied, anticenter open cluster Tombaugh 1. Using precision uvbyCaHβ photometry and high-resolution spectroscopy, we derive the cluster’s reddening, obtain photometric metallicity estimates, and, for the first time, present a detailed abundance analysis of 10 potential cluster stars (nine clump stars and one Cepheid). Using the radial position from the cluster center and multiple color indices, we have isolated a sample of unevolved, probable single-star members of Tombaugh 1. From 51 stars, the cluster reddening is found to be E(b-y) = 0.221 ± 0.006 or E(B-V) = 0.303 ± 0.008, where the errors refer to the internal standard errors of the mean. The weighted photometric metallicity from m1 and hk is [Fe/H] = -0.10 ± 0.02, while a match to the Victoria-Regina Strömgren isochrones leads to an age of 0.95 ± 0.10 Gyr and an apparent modulus of (m-M) = 13.10 ± 0.10. Radial velocities identify six giants as probable cluster members, and the elemental abundances of Fe, Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Y, Ba, Ce, and Nd have been derived for both the cluster and the field stars. Tombaugh 1 appears to be a typical inner thin disk, intermediate-age open cluster of slightly subsolar metallicity, located just beyond the solar circle, with solar elemental abundance ratios except for the heavy s-process elements, which are a factor of two above solar. Its metallicity is consistent with a steep metallicity gradient in the galactocentric region

  16. Prediction of orbiter RSI tile gap heating ratios from NASA/Ames double wedge model test

    NASA Technical Reports Server (NTRS)

    1978-01-01

    In-depth gap heating ratios for Orbiter RSI tile sidewalls were predicted based on near steady state temperature measurements obtained from double wedge model tests. An analysis was performed to derive gap heating ratios which would result in the best fit of test data; provide an assessment of open gap response, and supply the definition of gap filler requirements on the Orbiter. A comparison was made of these heating ratios with previously derived ratios in order to verify the extrapolation of the wing glove data to Orbiter flight conditions. The analysis was performed with the Rockwell TPS Multidimensional Heat Conduction Program for a 3-D, 2.0-inch thick flat RSI tile with 255 nodal points. The data from 14 tests was used to correlate with the analysis. The results show that the best-fit heating ratios at the station farthest upstream on the model for most gap depths were less than the extrapolated values of the wing glove model heating ratios. For the station farthest downstream on the model, the baseline heating ratios adequately predicted or over-predicted the test data.

  17. 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.

  18. REDBACK: an Open-Source Highly Scalable Simulation Tool for Rock Mechanics with Dissipative Feedbacks

    NASA Astrophysics Data System (ADS)

    Poulet, T.; Veveakis, M.; Paesold, M.; Regenauer-Lieb, K.

    2014-12-01

    Multiphysics modelling has become an indispensable tool for geoscientists to simulate the complex behaviours observed in their various fields of study where multiple processes are involved, including thermal, hydraulic, mechanical and chemical (THMC) laws. This modelling activity involves simulations that are computationally expensive and its soaring uptake is tightly linked to the increasing availability of supercomputing power and easy access to powerful nonlinear solvers such as PETSc (http://www.mcs.anl.gov/petsc/). The Multiphysics Object-Oriented Simulation Environment (MOOSE) is a finite-element, multiphysics framework (http://mooseframework.org) that can harness such computational power and allow scientists to develop easily some tightly-coupled fully implicit multiphysics simulations that run automatically in parallel on large clusters. This open-source framework provides a powerful tool to collaborate on numerical modelling activities and we are contributing to its development with REDBACK (https://github.com/pou036/redback), a module for Rock mEchanics with Dissipative feedBACKs. REDBACK builds on the tensor mechanics finite strain implementation available in MOOSE to provide a THMC simulator where the energetic formulation highlights the importance of all dissipative terms in the coupled system of equations. We show first applications of fully coupled dehydration reactions triggering episodic fluid transfer through shear zones (Alevizos et al, 2014). The dimensionless approach used allows focusing on the critical underlying variables which are driving the resulting behaviours observed and this tool is specifically designed to study material instabilities underpinning geological features like faulting, folding, boudinage, shearing, fracturing, etc. REDBACK provides a collaborative and educational tool which captures the physical and mathematical understanding of such material instabilities and provides an easy way to apply this knowledge to realistic

  19. Opening Lab Doors to High School Students: Keys to a Successful Engagement

    ERIC Educational Resources Information Center

    Slayton, Rebecca M.; Nelson, Keith A.

    2005-01-01

    A project to invite high school students into research laboratories to plan and carry out an investigation over several weeks, using the sophisticated equipment available there, can help to break down social barriers and enhance outreach activities.

  20. Integrating Omics and Alternative Splicing Reveals Insights into Grape Response to High Temperature1[OPEN

    PubMed Central

    Jiang, Jianfu; Liu, Xinna; Liu, Guotian; Li, Shaohua

    2017-01-01

    Heat stress is one of the primary abiotic stresses that limit crop production. Grape (Vitis vinifera) is a cultivated fruit with high economic value throughout the world, with its growth and development often influenced by high temperature. Alternative splicing (AS) is a widespread phenomenon increasing transcriptome and proteome diversity. We conducted high-temperature treatments (35°C, 40°C, and 45°C) on grapevines and assessed transcriptomic (especially AS) and proteomic changes in leaves. We found that nearly 70% of the genes were alternatively spliced under high temperature. Intron retention (IR), exon skipping, and alternative donor/acceptor sites were markedly induced under different high temperatures. Among all differential AS events, IR was the most abundant up- and down-regulated event. Moreover, the occurrence frequency of IR events at 40°C and 45°C was far higher than at 35°C. These results indicated that AS, especially IR, is an important posttranscriptional regulatory event during grape leaf responses to high temperature. Proteomic analysis showed that protein levels of the RNA-binding proteins SR45, SR30, and SR34 and the nuclear ribonucleic protein U1A gradually rose as ambient temperature increased, which revealed a reason why AS events occurred more frequently under high temperature. After integrating transcriptomic and proteomic data, we found that heat shock proteins and some important transcription factors such as MULTIPROTEIN BRIDGING FACTOR1c and HEAT SHOCK TRANSCRIPTION FACTOR A2 were involved mainly in heat tolerance in grape through up-regulating transcriptional (especially modulated by AS) and translational levels. To our knowledge, these results provide the first evidence for grape leaf responses to high temperature at simultaneous transcriptional, posttranscriptional, and translational levels. PMID:28049741