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Sample records for plate osteosynthesis solve

  1. Bridging plate osteosynthesis of humeral shaft fractures.

    PubMed

    Livani, Bruno; Belangero, William Dias

    2004-06-01

    This study was approved by the Ethics Committee of the Faculty of Medical Sciences and developed during November 2000 and July 2001 in the Orthopedic and Traumatology Department of UNICAMP. There were 15 patients, 11 males, age between 14 and 66 years. All fractures were unilateral. Of the 15 patients eight were polytraumatised, two of them had open fractures. The others had an isolated fracture of the humerus, of which one was open. None of the patients had previous lesions of the radial nerve, but in two patients there was a lesion of the brachial plexus. All of the patients underwent a bridging plate osteosynthesis of the humeral shaft fractures using only two small incisions proximal and distal to the fracture site. We used broad or narrow D.C.P. plates for large fragments mostly with 12 holes, fixed with two or three screws at each end. All cases united with an average time of 8-12 weeks, with the exception of one case with a grade III open fracture and a brachial plexus lesion on the same side. We had no major complications. All patients recovered good function of the limb without significant residual deformity. PMID:15135278

  2. Minimally invasive plate osteosynthesis using 3D printing for shaft fractures of clavicles: technical note.

    PubMed

    Jeong, Ho-Seung; Park, Kyoung-Jin; Kil, Kyung-Min; Chong, Suri; Eun, Hyeon-Jun; Lee, Tae-Soo; Lee, Jeong-Pyo

    2014-11-01

    This article describes a minimally invasive plate osteosynthesis technique for midshaft fractures of clavicles using intramedullary indirect reduction and prebent plates with 3D printing models. This technique allows for easy reduction of fractures with accurate prebent plates and minimal soft tissue injury around the fracture site.

  3. Redesign of Indonesian-made osteosynthesis plates to enhance their mechanical behavior.

    PubMed

    Dewo, P; van der Houwen, E B; Suyitno; Marius, R; Magetsari, R; Verkerke, G J

    2015-02-01

    Mechanical properties determined by fatigue strength, ductility, and toughness are important measures for osteosynthesis plates in order to tolerate some load-bearing situations caused by muscle contractions and weight-bearing effects. Previous study indicated that Indonesian-made plates showed lower mechanical strength compared to the European AO standard plate. High stress under load-bearing situations often starts from surface of the plate; we therefore refined the grain size of the surface by using shot peening and surface mechanical attrition treatment (SMAT). Single cycle bending tests showed that shot-peened and SMAT-treated plates had significantly higher load limit and bending stress compared to the original plates (p<0.05). Weibull analysis confirmed the improvement of proportional load limit of SMAT-treated plates. Fatigue limit also increased upon shot-peening and SMAT treatment (improvement ratio 18% and 27%, respectively). Significant improvement ratio of fatigue tests can be observed in SMAT-treated plates compared to the untreated and shot-peened plates. Fatigue performance demonstrated equivalent results between SMAT-treated and standard plate. These designated that mechanical properties of Indonesian-made plates can be improved upon SMAT treatment leading to significant enhancement of mechanical strength thus is comparable to the standard plate. Our findings highlight the benefits of SMAT treatment to improve mechanical strength of Indonesian-made osteosynthesis plates.

  4. [Angle-fixed plate fixation or double-plate osteosynthesis in fractures of the proximal humerus: a biomechanical study].

    PubMed

    Hessmann, Martin H; Korner, Jan; Hofmann, Alexander; Sternstein, Werner; Rommens, Pol M

    2008-06-01

    Internal fixation of fractures of the proximal humerus needs a high stability of fixation to avoid secondary loss of fixation. This is especially important in osteoporotic bone. In an experimental study, the biomechanical properties of the angle-fixed Philos plate (internal fixator) and a double-plate osteosynthesis using two one-third tubular plates were assessed. The fracture model was an unstable three-part fracture (AO type B2). Eight pairs of human cadaveric humeri were submitted to axial load and torque. In the first part of the study, it was assessed to which degree the original stiffness of the humeri could be restored after the osteotomy by the osteosynthesis procedure. Subsequently, subsidence during 200 cycles of axial loading and torque was analysed. During axial loading, the Philos plate was significantly stiffer and showed less irreversible deformation. Two double-plate fixations, but none of the Philos plate osteosynthesis, failed. During torsion, there were no significant differences between the two implants. From the biomechanical point of view, the angle-fixed Philos plate represents the implant of choice for the surgical fixation of highly unstable three-part fractures of the proximal humerus, as the internal fixator system is characterised by superior biomechanical properties.

  5. Intraoperative C-arm CT imaging in angular stable plate osteosynthesis of distal radius fractures.

    PubMed

    Mehling, I; Rittstieg, P; Mehling, A P; Küchle, R; Müller, L P; Rommens, P M

    2013-09-01

    The purpose of this study was to analyze the practicability and benefit of intraoperative C-arm computed tomography (CT) imaging in volar plate osteosynthesis of unstable distal radius fractures. During a 1 year period, intraoperative three dimensional (3D) imaging with the ARCADIS Orbic 3D was performed in addition to standard fluoroscopy in 51 cases. The volar angular stable plate oesteosyntheses were analyzed intraoperatively and, if necessary, improved immediately. The duration of the scan and radiation exposure dose were measured. On average, performance of the scan and analysis of the CT dataset took 6.7 minutes. In 31.3% of the surgeries a misplacement of screws was detected and correction was done immediately. C-arm CT imaging can easily be integrated in the normal course of surgery. As a complement to the standard 2D-fluoroscopy, the C-arm CT is a useful tool to evaluate the quality of osteosynthesis.

  6. [Intramedullary nailing of the humerus as an alternative to conservative therapy and to plate osteosynthesis].

    PubMed

    Kessler, S B; Nast-Kolb, D; Brunner, U; Wischhöfer, E

    1996-06-01

    For humeral shaft fractures conservative treatment, plate osteosynthesis and IM nailing are possible options according to the localization, type of fracture or additional soft tissue problems. While the majority of humeral shaft fractures is still treated conservatively, today an increasing number of fractures is felt to be suitable for ORIF. Pseudarthroses, pathological fractures, multiple fractures or polytrauma, very severe open fractures, soft tissue interposition or concomitant nerve or vascular injuries are all indications for operative treatment. We think that plate osteosynthesis is still the standard. IM interlocking nailing has been shown to be advantageous for early rehabilitation and low radial nerve damage rates. In IM nailing it is still necessary to improve the implants and implantation techniques. A retrograde extra-articular nailing technique with elastic implants is preferable. The preliminary results for a newly developed elastic nail ("Monachia Nail") in 18 patients are very promising with respect to the implantation technique, fracture healing and functional rehabilitation.

  7. Influence of the osteosynthesis plate on ultrasound propagation in the bone

    PubMed Central

    Bezuti, Márcio Takey; Mandarano-Filho, Luiz Garcia; Barbieri, Giuliano; Mazzer, Nilton; Barbieri, Cláudio Henrique

    2014-01-01

    Objective: To analyze the influence of steel plates for osteosynthesis on the velocity of ultrasound propagation (VU) through the bone. Methods: The transverse coronal and sagittal velocity of ultrasound propagation underwater were measured on the intact bone and then on assemblies of the same bone with two types of osteosynthesis plates (DCP and semi tubular), fixed onto the dorsal side of the bones. The first arriving signal (FAS) was the ultrasound parameter used, taking the coronal and sagittal diameters as the distances to calculate velocity. Intergroup statistical comparisons were made at significance level of 1% (p<0.01). Results: Velocity was higher on the intact bones than on the bone-plate assemblies and higher for the semitubular than for the compression plates, although differences were not statistically significant for most comparisons (p=0.0132 to 0.9884), indicating that the steel plates do not interfere significantly with ultrasound wave propagation through the bone-plate assemblies. Conclusion: The velocity reduction effect was attributed to the greater reflection coefficient of the steel as compared to that of bone and water. Ultrasonometry can, thus, be used in the evaluation of healing of fractures fixed with steel plates. Experimental Study. PMID:25328436

  8. [Effect of bending on shot peened and polished osteosynthesis plates].

    PubMed

    Starker, M; Fröhling, M; Hirsch, T

    1991-03-01

    Shot peening can increase the fatigue strength of commercially available surgical plates made of 1.4435 alloy by 40% even in a corrosive environment. Our investigations show that residual stresses resulting from shot peening are reduced by additional bending of the plates. In such plates smaller tensile residual stresses were found than after polishing of the plates. Bending of polished plates results in considerable tensile residual stresses. The hardening achieved by shot peening is not reduced by bending. As the fatigue strength of soft materials depends mainly on the hardening and less on the residual stresses, only little influence of the changed residual stresses on the fatigue strength can be expected. Shot peening of surgical implants thus means an improvement in quality. PMID:2054460

  9. Minimal invasive long PHILOS®-plate osteosynthesis in metadiaphyseal fractures of the proximal humerus.

    PubMed

    Rancan, Mario; Dietrich, Michael; Lamdark, Tenzin; Can, Uenal; Platz, Andreas

    2010-12-01

    Minimal invasive plate osteosynthesis (MIPO) not only meets the criteria of a "biological" osteosynthesis by minimising invasivity as well as iatrogenic soft tissue damage, but can also provide adequate stability for fracture healing and early functional aftertreatment. Up to date, only few publications report on MIPO of humeral shaft fractures mainly using the anterolateral deltopectoral approach for proximal plate insertion. Objective of the present study was to assess the feasibility and clinical outcome of MIPO for metadiaphyseal fractures of the proximal humerus through a lateral approach using angular stable long PHILOS(®)-plates. We retrospectively evaluated 29 patients (mean age 77 years, range 48-95 years) with displaced metadiaphyseal fractures of the proximal humerus treated with MIPO technique. For the first time, an angular stable long PHILOS(®)-plate through a lateral deltoid-split approach proximally and a brachialis/brachioradialis intermuscular approach with exposure of the radial nerve distally, were used. There were no infections and no iatrogenic injuries to the axillary and radial nerve. One patient showed subacromial impingement and one patient had to be reoperated for redislocation of the distal fragment with screw breakage, which was most likely due to incorrect screw placement. This patient was successfully operated using the same method and implant. Besides one patient who refused further follow-up, 28 patients could be followed up to a mean of 8 months (range 3-12 months) each with an entirely healed fracture. Furthermore, patient's quality of life was documented using the SF-36 questionnaire. Comparison with published United States normative data showed no significant deficits in the physical as well as in the mental domains 8 months after MIPO. Minimal invasive long PHILOS(®)-plate osteosynthesis using a combined lateral deltoid-split and brachialis/brachioradialis intermuscular approach proved to be a safe procedure for the

  10. Treatment of Intercondylar Humeral Fractures With 3D-Printed Osteosynthesis Plates.

    PubMed

    Shuang, Feng; Hu, Wei; Shao, Yinchu; Li, Hao; Zou, Hongxing

    2016-01-01

    The aim of the study was to evaluate the efficacy custom 3D-printed osteosynthesis plates in the treatment of intercondylar humeral fractures.Thirteen patients with distal intercondylar humeral fractures were randomized to undergo surgery using either conventional plates (n = 7) or 3D-printed plates (n = 6) at our institution from March to October 2014. Both groups were compared in terms of operative time and elbow function at 6 month follow-up.All patients were followed-up for a mean of 10.6 months (range: 6-13 months). The 3D-printing group had a significantly shorter mean operative time (70.6 ± 12.1 min) than the conventional plates group (92.3 ± 17.4 min). At the last follow-up period, there was no significant difference between groups in the rate of patients with good or excellent elbow function, although the 3D-printing group saw a slightly higher rate of good or excellent evaluations (83.1%) compared to the conventional group (71.4%).Custom 3D printed osteosynthesis plates are safe and effective for the treatment of intercondylar humeral fractures and significantly reduce operative time. PMID:26817880

  11. Treatment of Intercondylar Humeral Fractures With 3D-Printed Osteosynthesis Plates

    PubMed Central

    Shuang, Feng; Hu, Wei; Shao, Yinchu; Li, Hao; Zou, Hongxing

    2016-01-01

    Abstract The aim of the study was to evaluate the efficacy custom 3D-printed osteosynthesis plates in the treatment of intercondylar humeral fractures. Thirteen patients with distal intercondylar humeral fractures were randomized to undergo surgery using either conventional plates (n = 7) or 3D-printed plates (n = 6) at our institution from March to October 2014. Both groups were compared in terms of operative time and elbow function at 6 month follow-up. All patients were followed-up for a mean of 10.6 months (range: 6–13 months). The 3D-printing group had a significantly shorter mean operative time (70.6 ± 12.1 min) than the conventional plates group (92.3 ± 17.4 min). At the last follow-up period, there was no significant difference between groups in the rate of patients with good or excellent elbow function, although the 3D-printing group saw a slightly higher rate of good or excellent evaluations (83.1%) compared to the conventional group (71.4%). Custom 3D printed osteosynthesis plates are safe and effective for the treatment of intercondylar humeral fractures and significantly reduce operative time. PMID:26817880

  12. Modular adaptive bone plate for humerus bone osteosynthesis.

    PubMed

    Tarniţă, Daniela; Tarniţă, D N; Bîzdoacă, N; Tarniţă, Corina; Berceanu, C; Boborelu, C

    2009-01-01

    The present paper describes a bionics application of shape memory alloy in construction of orthopedic implant. The main idea of this paper is related to design modular adaptive implants for fractured bones. In order to target the efficiency of medical treatment, the implant has to protect the fractured bone, for the healing period, undertaking much as is possible from the daily usual load of the healthy bones. The adaptability of this design is related to medical possibility of the doctor to made the implant to correspond to patient specifically anatomy. Using a CT-realistic numerical humerus bone model, the mechanical simulation of the osteosyntesis process for humerus bone using staples made out of Nitinol. The stress and displacements diagrams for bone, for plate modules and for staples, are presented. PMID:19690773

  13. Secondary Radial Nerve Palsy after Minimally Invasive Plate Osteosynthesis of a Distal Humeral Shaft Fracture

    PubMed Central

    Bichsel, Ursina; Nyffeler, Richard Walter

    2015-01-01

    Minimally invasive plate osteosynthesis is a widely used procedure for the treatment of fractures of the femur and the tibia. For a short time it is also used for the treatment of humeral shaft fractures. Among other advantages, the ambassadors of this technique emphasize the lower risk of nerve injuries when compared to open reduction and internal fixation. We report the case of secondary radial nerve palsy caused by percutaneous fixation of a plate above the antecubital fold. The nerve did not recover and the patient needed a tendon transfer to regain active extension of the fingers. This case points to the importance of adequate exposure of the bone and plate if a humeral shaft fracture extends far distally. PMID:26558125

  14. Central acetabular fracture with dislocation treated by minimally invasive plate osteosynthesis.

    PubMed

    2015-06-01

    Central acetabular fractures with dislocation are usually the result of high-energy trauma, resulting in joint incongruity, and are frequently associated with other injuries. Open reduction and internal fixation has been the standard treatment for acetabular fractures, but it is associated with extensive surgical trauma, and complications such as haematoma formation, iatrogenic nerve injury, and heterotopic ossification. We present the case of a 63-year-old female who sustained a central acetabular fracture of the hip with dislocation as a result of an automobile collision. Closed reduction of the dislocation was performed, and the fracture was managed by minimally invasive plate osteosynthesis using a specially prepared plate. At 01 year postoperatively, radiographs showed the fracture to have been well-healed with good congruity of the joint. However, heterotopic ossification of the joint was noted. The technique allowed reduction of the fracture with minimal surgical trauma.

  15. Central acetabular fracture with dislocation treated by minimally invasive plate osteosynthesis.

    PubMed

    2015-06-01

    Central acetabular fractures with dislocation are usually the result of high-energy trauma, resulting in joint incongruity, and are frequently associated with other injuries. Open reduction and internal fixation has been the standard treatment for acetabular fractures, but it is associated with extensive surgical trauma, and complications such as haematoma formation, iatrogenic nerve injury, and heterotopic ossification. We present the case of a 63-year-old female who sustained a central acetabular fracture of the hip with dislocation as a result of an automobile collision. Closed reduction of the dislocation was performed, and the fracture was managed by minimally invasive plate osteosynthesis using a specially prepared plate. At 01 year postoperatively, radiographs showed the fracture to have been well-healed with good congruity of the joint. However, heterotopic ossification of the joint was noted. The technique allowed reduction of the fracture with minimal surgical trauma. PMID:26060171

  16. Numerical simulations of human tibia osteosynthesis using modular plates based on Nitinol staples.

    PubMed

    Tarniţă, Daniela; Tarniţă, D N; Popa, D; Grecu, D; Tarniţă, Roxana; Niculescu, D; Cismaru, F

    2010-01-01

    The shape memory alloys exhibit a number of remarkable properties, which open new possibilities in engineering and more specifically in biomedical engineering. The most important alloy used in biomedical applications is NiTi. This alloy combines the characteristics of the shape memory effect and superelasticity with excellent corrosion resistance, wear characteristics, mechanical properties and a good biocompatibility. These properties make it an ideal biological engineering material, especially in orthopedic surgery and orthodontics. In this work, modular plates for the osteosynthesis of the long bones fractures are presented. The proposed modular plates are realized from identical modules, completely interchangeable, made of titanium or stainless steel having as connecting elements U-shaped staples made of Nitinol. Using computed tomography (CT) images to provide three-dimensional geometric details and SolidWorks software package, the three dimensional virtual models of the tibia bone and of the modular plates are obtained. The finite element models of the tibia bone and of the modular plate are generated. For numerical simulation, VisualNastran software is used. Finally, displacements diagram, von Misses strain diagram, for the modular plate and for the fractured tibia and modular plate ensemble are obtained.

  17. Numerical simulations of human tibia osteosynthesis using modular plates based on Nitinol staples.

    PubMed

    Tarniţă, Daniela; Tarniţă, D N; Popa, D; Grecu, D; Tarniţă, Roxana; Niculescu, D; Cismaru, F

    2010-01-01

    The shape memory alloys exhibit a number of remarkable properties, which open new possibilities in engineering and more specifically in biomedical engineering. The most important alloy used in biomedical applications is NiTi. This alloy combines the characteristics of the shape memory effect and superelasticity with excellent corrosion resistance, wear characteristics, mechanical properties and a good biocompatibility. These properties make it an ideal biological engineering material, especially in orthopedic surgery and orthodontics. In this work, modular plates for the osteosynthesis of the long bones fractures are presented. The proposed modular plates are realized from identical modules, completely interchangeable, made of titanium or stainless steel having as connecting elements U-shaped staples made of Nitinol. Using computed tomography (CT) images to provide three-dimensional geometric details and SolidWorks software package, the three dimensional virtual models of the tibia bone and of the modular plates are obtained. The finite element models of the tibia bone and of the modular plate are generated. For numerical simulation, VisualNastran software is used. Finally, displacements diagram, von Misses strain diagram, for the modular plate and for the fractured tibia and modular plate ensemble are obtained. PMID:20191135

  18. The Role of Minimally Invasive Plate Osteosynthesis in Rib Fixation: A Review.

    PubMed

    Bemelman, Michael; van Baal, Mark; Yuan, Jian Zhang; Leenen, Luke

    2016-02-01

    More than a century ago, the first scientific report was published about fracture fixation with plates. During the 1950's, open reduction and plate fixation for fractures were standardized by the founders of Arbeitsgemeinschaft für osteosynthesefragen/Association for the Study of Internal Fixation. Since the introduction of plate fixation for fractures, several plates and screws have been developed, all with their own characteristics. To accomplice more fracture stability, it was thought the bigger the plate, the better. The counter side was a compromised blood supply of the bone, often resulting in bone necrosis and ultimately delayed or non-union. With the search and development of new materials and techniques for fracture fixation, less invasive procedures have become increasingly popular. This resulted in the minimally invasive plate osteosynthesis (MIPO) technique for fracture fixation. With the MIPO technique, procedures could be performed with smaller incisions and thus with less soft tissue damage and a better preserved blood supply. The last 5 years rib fixation has become increasingly popular, rising evidence has become available suggesting that surgical rib fixation improves outcome of patients with a flail chest or isolated rib fractures. Many surgical approaches for rib fixation have been described in the old literature, however, most of these techniques are obscure nowadays. Currently mostly large incisions with considerable surgical insult are used to stabilize rib fractures. We think that MIPO deserves a place in the surgical treatment of rib fractures. We present the aspects of diagnosis, preoperative planning and operative techniques in regard to MIPO rib fixation.

  19. The Role of Minimally Invasive Plate Osteosynthesis in Rib Fixation: A Review

    PubMed Central

    Bemelman, Michael; van Baal, Mark; Yuan, Jian Zhang; Leenen, Luke

    2016-01-01

    More than a century ago, the first scientific report was published about fracture fixation with plates. During the 1950’s, open reduction and plate fixation for fractures were standardized by the founders of Arbeitsgemeinschaft für osteosynthesefragen/Association for the Study of Internal Fixation. Since the introduction of plate fixation for fractures, several plates and screws have been developed, all with their own characteristics. To accomplice more fracture stability, it was thought the bigger the plate, the better. The counter side was a compromised blood supply of the bone, often resulting in bone necrosis and ultimately delayed or non-union. With the search and development of new materials and techniques for fracture fixation, less invasive procedures have become increasingly popular. This resulted in the minimally invasive plate osteosynthesis (MIPO) technique for fracture fixation. With the MIPO technique, procedures could be performed with smaller incisions and thus with less soft tissue damage and a better preserved blood supply. The last 5 years rib fixation has become increasingly popular, rising evidence has become available suggesting that surgical rib fixation improves outcome of patients with a flail chest or isolated rib fractures. Many surgical approaches for rib fixation have been described in the old literature, however, most of these techniques are obscure nowadays. Currently mostly large incisions with considerable surgical insult are used to stabilize rib fractures. We think that MIPO deserves a place in the surgical treatment of rib fractures. We present the aspects of diagnosis, preoperative planning and operative techniques in regard to MIPO rib fixation. PMID:26889439

  20. Minimally invasive plate osteosynthesis in the treatment of proximal humeral fracture

    PubMed Central

    Leung, F.; Chan, C. F.; Chow, S. P.

    2006-01-01

    The management of fractures of the proximal shaft of the humerus has been evolving since the development of new techniques and new implants in recent years. It seems that this kind of fracture has an increasing incidence in the older, osteoporotic population. In the last 2 years, we have operated on 17 patients, with an average age of 65, who had proximal humeral shaft fractures treated by minimally invasive percutaneous osteosynthesis (MIPO) technique using the metaphyseal locking compression plate. Our study evaluated the surgical technique used and the outcome for these patients with regards to their range of movement and shoulder function. Our results showed that all the patients could achieve at least 140º of shoulder abduction in the first 6 months after the operation, except for three patients who had shoulder impingement. These patients had an average Constant score of 76.8. All fractures had bony union at 6 months, except one, which was probably due to poor reduction in the initial operation. Another complication that we encountered was radial nerve neuropraxia. The ways to prevent these complications are discussed. In conclusion, MIPO fixation using the metaphyseal locking compression plate is a good option for the management of proximal humeral shaft fractures. It provides early functional recovery, but we had to pay special attention to some of the surgical details in order to minimise complications. PMID:17033765

  1. Plating osteosynthesis of mid-distal humeral shaft fractures: minimally invasive versus conventional open reduction technique

    PubMed Central

    Zeng, Bingfang; He, Xiaojian; Chen, Qi; Hu, Shundong

    2009-01-01

    Results of two methods, conventional open reduction–internal plating and minimally invasive plating osteosynthesis (MIPO), in the treatment of mid-distal humeral shaft fractures were compared. Thirty-three patients were retrospectively analysed and divided into two groups. Group A (n = 17) patients were treated by MIPO and group B (n = 16) by conventional plating. The mean operation time in group A was 92.35 ± 57.68 minutes and 103.12 ± 31.08 minutes in group B (P = 0.513). Iatrogenic radial nerve palsy in group A was 0% (0/17) and 31.3% in group B (5/16 (P = 0.012). The mean fracture union time in group A was 15.29 ± 4.01 weeks (range 8–24 weeks), and 21.25 ± 13.67 weeks (range 10–58 weeks) in group B (P = 0.095). The mean UCLA end-result score in group A was 34.76 ± 0.56 points (range 33–35), and 34.38 ± 1.41 points (range 30–35) in group B (P = 0.299). The mean MEPI in group A was 99.41 ± 2.43 points (range 90–100) and 99.69 ± 1.25 points (range 95–100) in group B (P = 0.687). When compared to the conventional plating techniques, MIPO offers advantages in terms of reduced incidence of iatrogenic radial nerve palsies and accelerated fracture union and a similar functional outcome with respect to shoulder and elbow function. PMID:19301000

  2. Comparing the In Vitro Stiffness of Straight-DCP, Wave-DCP, and LCP Bone Plates for Femoral Osteosynthesis.

    PubMed

    Mariolani, José Ricardo Lenzi; Belangero, William Dias

    2013-01-01

    The objective of this study was to compare the Locking Compression Plate (LCP) with the more cost-effective straight-dynamic compression plate (DCP) and wave-DCPs by testing in vitro the effects of plate stiffness on different types of diaphyseal femur fractures (A, B, and C, according to AO classification). The bending structural stiffness of each plate was obtained from four-point bending tests according to ASTM F382-99(2008). The plate systems were tested by applying compression/bending in different osteosynthesis simulation models using wooden rods to simulate the fractured bone fragments. Kruskal-Wallis test showed no significant difference in the bending structural stiffness between the three plate models. Rank-transformed two-way ANOVA showed significant influence of plate type, fracture type, and interaction plate versus fracture on the stiffness of the montages. The straight-DCP produced the most stable model for types B and C fractures, which makes its use advantageous for complex nonosteoporotic fractures that require minimizing focal mobility, whereas no difference was found for type A fracture. Our results indicated that DCPs, in straight or wave form, can provide adequate biomechanical properties for fixing diaphyseal femoral fractures in cases where more modern osteosynthesis systems are cost restrictive.

  3. Treatment of Humeral Shaft Fractures: Minimally Invasive Plate Osteosynthesis Versus Open Reduction and Internal Fixation

    PubMed Central

    Esmailiejah, Ali Akbar; Abbasian, Mohammad Reza; Safdari, Farshad; Ashoori, Keyqobad

    2015-01-01

    Background: The optimal technique for operative fixation of humeral shaft fractures remains controversial and warrants research. Objectives: The purpose of the current study was to compare the functional and clinical outcomes of conventional open reduction and internal fixation (ORIF) with minimally invasive plate osteosynthesis (MIPO) in patients with fractures in two-third distal humeral shaft. Patients and Methods: In the current prospective case-control study, 65 patients with humeral shaft fractures were treated using ORIF (33 patients) or MIPO (32 patients). Time of surgery, time of union, incidence of varus deformity and complications were compared between the two groups. Also, the university of California-Los Angeles (UCLA) shoulder rating scale and Mayo Elbow performance score (MEPS) were used to compare the functional outcomes between the two groups. Results: The median of union time was shorter in the MIPO group (4 months versus 5 months). The time of surgery and functional outcomes based on the UCLA and MEPS scores were the same. The incidence of varus deformity was more than 5° and was higher and the incidence of nonunion, infection and iatrogenic radial nerve injury were lower in the MIPO group; however, the differences were not significant. Conclusions: Due to the shorter union time, to some extent less complication rate and comparable functional and clinical results, the authors recommend to use the MIPO technique in treating the mid-distal humeral shaft fracture. PMID:26543844

  4. Minimally invasive plate osteosynthesis for humeral shaft fractures: are results reproducible?

    PubMed Central

    Concha, Juan M.; Sandoval, Alejandro

    2009-01-01

    Minimally invasive plate osteosynthesis (MIPO) has been advocated as a safe approach to humeral shaft fracture management. We evaluated the reproducibility of this technique in a regional hospital. Thirty-five patients underwent MIPO of humerus shaft fractures. Fifteen patients had an open fracture, six a preoperative radial nerve palsy, and nine a concomitant thoracic, musculoskeletal or vascular injury. At an average 12-month follow-up, 91% of fractures healed after a mean of 12 weeks (range, 8–16). Two infections occurred. Final alignment averaged 4° of varus (range, 5° of valgus to 20° of varus). Active elbow ROM averaged 114° (range, 60–135°) and was less than 100° in nine elbows. Five of six preoperative radial nerve injuries recovered spontaneously. Healing and infection rates in this study are consistent with those reported in the literature. Lower elbow ROM and higher fracture angulation at healing were nevertheless found. MIPO is technically demanding and requires adequate intraoperative imaging and surgical experience in order to obtain adequate fracture alignment. Brachialis muscle scarring and inadequate postoperative rehabilitation may be involved in limited elbow range of motion. PMID:19844708

  5. Plate on plate osteosynthesis for the treatment of nonhealed periplate fractures.

    PubMed

    Arealis, Georgios; Nikolaou, Vassilios S; Lacon, Andrew; Ashwood, Neil; Hamlet, Mark

    2014-01-01

    Purpose. The purpose of this paper is to present our technique for the treatment of periplate fractures. Methods. From 2009 to 2012 we treated three patients. In all cases the existing plate was left and the new one placed over the existing. Locking screws were placed through both plates. The other screws in the new plate were used as best suited the fracture. Results. In all cases less than 6 months had passed between fractures. None of the original fractures had healed. Mean followup was 2 years. All fractures proceeded to union within 7 months. No complications were recorded. All the patients returned to their normal activities and were satisfied with the results of their treatment. Conclusion. Our plate on plate technique is effective for the treatment of periplate fractures. A solid fusion can be achieved at the new fracture site without disturbing the previous fixation.

  6. Plate on Plate Osteosynthesis for the Treatment of Nonhealed Periplate Fractures

    PubMed Central

    Nikolaou, Vassilios S.; Lacon, Andrew; Ashwood, Neil; Hamlet, Mark

    2014-01-01

    Purpose. The purpose of this paper is to present our technique for the treatment of periplate fractures. Methods. From 2009 to 2012 we treated three patients. In all cases the existing plate was left and the new one placed over the existing. Locking screws were placed through both plates. The other screws in the new plate were used as best suited the fracture. Results. In all cases less than 6 months had passed between fractures. None of the original fractures had healed. Mean followup was 2 years. All fractures proceeded to union within 7 months. No complications were recorded. All the patients returned to their normal activities and were satisfied with the results of their treatment. Conclusion. Our plate on plate technique is effective for the treatment of periplate fractures. A solid fusion can be achieved at the new fracture site without disturbing the previous fixation. PMID:24967127

  7. Total Hip Arthroplasty Using a Short-Stemmed Femoral Component in the Presence of a Long Dynamic Condylar Screw Osteosynthesis Plate

    PubMed Central

    Buttaro, Martin; Piuzzi, Nicolas; Comba, Fernando; Zanotti, Gerardo; Piccaluga, Francisco

    2014-01-01

    We present a potential indication of a short-stemmed femoral component in a patient with multiple comorbidities presenting with hip posttraumatic osteoarthritis and a long dynamic condylar screw osteosynthesis plate. Removal of the plate and implantation of a long stem would have been related to a much longer operative time and potential local or systemic complications. PMID:25349758

  8. Management of fractures of the distal third tibia by minimally invasive plate osteosynthesis – A prospective series of 50 patients

    PubMed Central

    Paluvadi, Siddhartha Venkata; Lal, Hitesh; Mittal, Deepak; Vidyarthi, Kandarp

    2014-01-01

    Background Minimally invasive plate osteosynthesis (MIPO) is an established technique for fixation of fractures of the distal third tibia. Our study aimed to manage intra articular and extraarticular fractures of the distal third tibia by the minimally invasive plate osteosynthesis technique and follow them prospectively. Clinical and radiological outcomes were studied and clinical indications & efficacy of the procedure reviewed. Though many studies on the subject have been done previously, these have been retrospective reviews or small series. Methods From May 2010 to May 2013, 50 patients of closed distal tibial fractures were operated by MIPO technique with a distal tibial anatomical locking plate having 4.5/5 proximal and 3.5/4 distal screw holes. The follow up duration was for 3 years. Results The mean fracture healing time was 21.4 weeks (range 16–32 weeks) and average AOFAS score 95.06 was out of a total possible 100 points. At last follow up, superficial infection occurred in 5 patients (10%); deep infection, implant failure and malunion in 1-patient each (2%). Conclusion MIPO technique provides good, though slightly delayed bone healing and decreases incidence of nonunion and need for bone grafting. This technique should be used in distal tibia fractures where locked nailing cannot be done like fractures with small distal metaphyseal fragments, vertical splits, markedly comminuted fractures and in fractures with intra-articular extension. PMID:25983486

  9. OSTEOSYNTHESIS OF PROXIMAL HUMERAL END FRACTURES WITH FIXED-ANGLE PLATE AND LOCKING SCREWS: TECHNIQUE AND RESULTS

    PubMed Central

    Cohen, Marcio; Amaral, Marcus Vinicius; Monteiro, Martim; Brandão, Bruno Lobo; Motta Filho, Geraldo Rocha

    2015-01-01

    Describe the results of proximal humeral fractures surgically treated with the Philos locking plate system. Method: Between March 2003 and October 2004 we prospectively reviewed 24 of 26 patients with proximal humerus fractures treated with a Philos plate. The mean follow-up time was 12 months and the mean age of patients was 57 years. Six patients had four-part proximal humerus fractures, 11 patients had three-part proximal humerus fractures, and nine patients had two-part proximal humerus fractures. Clinical evaluation was performed using the University of California at Los Angeles (UCLA) criteria. Results: The mean UCLA score was 30 points (17-34). All fractures showed union. Three patients showed fracture union at varus position. The mean UCLA score for these patients was 27 points. Conclusion: Osteosynthesis with Philos plate provides a stable fixation method with good functional outcome. PMID:26998460

  10. Callus Formation and Mineralization after Fracture with Different Fixation Techniques: Minimally Invasive Plate Osteosynthesis versus Open Reduction Internal Fixation.

    PubMed

    Xu, Haitao; Xue, Zichao; Ding, Haoliang; Qin, Hui; An, Zhiquan

    2015-01-01

    Minimally invasive plate osteosynthesis(MIPO) has been considered as an alternative for fracture treatment. Previous study has demonstrated that MIPO technique has the advantage of less soft tissue injury compared with open reduction internal fixation (ORIF). However, the comparison of callus formation and mineralization between two plate osteosynthesis methods remains unknown. In this experiment, ulna fracture model was established in 42 beagle dogs. The fractures underwent reduction and internal fixation with MIPO or ORIF. Sequential fluorescent labeling and radiographs were applied to determine new callus formation and mineralization in two groups after operation. At 4, 8 and 12 weeks postoperatively, the animals were selected to be sacrificed and the ulna specimens were analyzed by Micro-CT. The sections were also treated with Masson staining for histological evaluation. More callus formation was observed in MIPO group in early stage of fracture healing. The fracture union rate has no significant difference between two groups. The results indicate that excessive soft tissue stripping may impact early callus formation. As MIPO technique can effectively reduce soft tissue injury with little incision, it is considered to be a promising alternative for fracture fixation.

  11. Callus Formation and Mineralization after Fracture with Different Fixation Techniques: Minimally Invasive Plate Osteosynthesis versus Open Reduction Internal Fixation

    PubMed Central

    Ding, Haoliang; Qin, Hui; An, Zhiquan

    2015-01-01

    Minimally invasive plate osteosynthesis(MIPO) has been considered as an alternative for fracture treatment. Previous study has demonstrated that MIPO technique has the advantage of less soft tissue injury compared with open reduction internal fixation (ORIF). However, the comparison of callus formation and mineralization between two plate osteosynthesis methods remains unknown. In this experiment, ulna fracture model was established in 42 beagle dogs. The fractures underwent reduction and internal fixation with MIPO or ORIF. Sequential fluorescent labeling and radiographs were applied to determine new callus formation and mineralization in two groups after operation. At 4, 8 and 12 weeks postoperatively, the animals were selected to be sacrificed and the ulna specimens were analyzed by Micro-CT. The sections were also treated with Masson staining for histological evaluation. More callus formation was observed in MIPO group in early stage of fracture healing. The fracture union rate has no significant difference between two groups. The results indicate that excessive soft tissue stripping may impact early callus formation. As MIPO technique can effectively reduce soft tissue injury with little incision, it is considered to be a promising alternative for fracture fixation. PMID:26444295

  12. Treatment of Palatal Fractures by Osteosynthesis with 2.0-mm Locking Plates as External Fixator

    PubMed Central

    Cienfuegos, Ricardo; Sierra, Eduardo; Ortiz, Benjamin; Fernández, Gerardo

    2010-01-01

    Treatment options for palatal fractures range from orthodontic braces, acrylic bars, and arch bars for maxillomandibular fixation to internal fixation, with plates and screws placed under the palate mucosa and periosteum, together with pyriform aperture or alveolar plating plus buttress reconstruction. Forty-five patients, ages 4 to 56, were treated using medium- or high-profile locking plates placed over the palatal mucosa as an external fixator for palatal fractures, together with treatment for other associated facial fractures. In open fractures, plates were placed after approximating the edges of the mucosal wounds. Plates and screws for palate fixation were removed at 12 weeks, when computed tomography scans provided evidence of fracture healing. All palatal fractures healed by 12 weeks, with no cases of mucosal necrosis, bone exposure, fistulae, or infections. This approach achieves adequate stability, reduces the risk of bone and mucosal necrosis, and promotes healing of mucosal wounds in case of open fractures. PMID:22132261

  13. [Intra-articular fracture of the distal radius: results following osteosynthesis with a support plate].

    PubMed

    Ferguson, G A; Leutenegger, A; Mark, G; Breiter, H; Rüedi, T

    1989-01-01

    The treatment of comminuted intra-articular fractures of the distal radius often requires an operative fixation. Beside the recently recommended external fixator, the support plate fixation offers a helpful alternative to treatment. Between 1980 and 1986, 30 wrists in 29 patients with intra-articular fractures of the distal radius were stabilized with a buttress plate an the Kantonsspital Chur, Switzerland. The mean follow-up-time was 15 months. These follow-ups showed that the buttress plate in treatment of complicated intra-articular fractures allows a satisfactory reduction and stabilization with restoration of the articular congruity and the possibility for early active assisted motion. Buttress plate fixation still remains a demanding technique, which in complicated cases, should be reserved for the experienced surgeon. PMID:2500786

  14. Osteosynthesis of Proximal Humeral Fractures with the Fixed Angle PHILOS-plate.

    PubMed

    Klitscher, Daniela; Blum, Jochen; Andreas, Dominik; Hessmann, Martin; Kuechle, Raphael; du Prel, Jean-Baptist; Rommens, Pol Maria

    2008-02-01

    In a retrospective study we analyzed the functional and radiological outcome of 30 proximal humeral fractures, treated by PHILOS-plate, a fixed-angle device. Two of them were characterized as type Neer III, 14 as type Neer IV, 5 as type Neer V and 9 as type Neer VI. There were 2 2-part, 16 3-part and 12 4-part fractures. According to the constant-score, the normalized constant-score and the UCLA-score, good to excellent results were obtained in 66.7, 76.7 and 76.7%. Twenty-six (86.7%) patients had no or mild pain. Active forward flexion and active abduction over 90° was possible in 26 (86.7%) cases. Four (13.3%) patients developed partial avascular necrosis. Screw perforation was seen in 3 (10%) cases, delayed union in 1 (3.3%) case, malunion in 1 case and a loosening of plate and screws in another one. A secondary varus displacement of 5°-35° with a mean of 7° was found in 19 (63.3%) cases. The average time to union was 75 days. Fixation with PHILOS-plate is an adequate treatment for displaced 2- to 4-part fractures. Even in dislocated or 4-part fractures or in patients over 65 years good to excellent results were seen in the majority of cases.

  15. In vivo degradation of magnesium plate/screw osteosynthesis implant systems: Soft and hard tissue response in a calvarial model in miniature pigs.

    PubMed

    Schaller, Benoit; Saulacic, Nikola; Imwinkelried, Thomas; Beck, Stefan; Liu, Edwin Wei Yang; Gralla, Jan; Nakahara, Ken; Hofstetter, Willy; Iizuka, Tateyuki

    2016-03-01

    Biodegradable magnesium plate/screw osteosynthesis systems were implanted on the frontal bone of adult miniature pigs. The chosen implant geometries were based on existing titanium systems used for the treatment of facial fractures. The aim of this study was to evaluate the in vivo degradation and tissue response of the magnesium alloy WE43 with and without a plasma electrolytic surface coating. Of 14 animals, 6 received magnesium implants with surface modification (coated), 6 without surface modification (uncoated), and 2 titanium implants. Radiological examination of the skull was performed at 1, 4, and 8 weeks post-implantation. After euthanasia at 12 and 24 weeks, X-ray, computed tomography, and microfocus computed tomography analyses and histological and histomorphological examinations of the bone/implant blocks were performed. The results showed a good tolerance of the plate/screw system without wound healing disturbance. In the radiological examination, gas pocket formation was found mainly around the uncoated plates 4 weeks after surgery. The micro-CT and histological analyses showed significantly lower corrosion rates and increased bone density and bone implant contact area around the coated screws compared to the uncoated screws at both endpoints. This study shows promising results for the further development of coated magnesium implants for the osteosynthesis of the facial skeleton.

  16. Treatment of the humeral shaft fractures - minimally invasive osteosynthesis with bridge plate versus conservative treatment with functional brace: study protocol for a randomised controlled trial

    PubMed Central

    2013-01-01

    Background Humeral shaft fractures account for 1 to 3% of all fractures in adults and for 20% of all humeral fractures. Non-operative treatment is still the standard treatment of isolated humeral shaft fractures, although this method can present unsatisfactory results. Surgical treatment is reserved for specific conditions. Modern concepts of internal fixation of long bone shaft fractures advocate relative stabilisation techniques with no harm to fracture zone. Recently described, minimally invasive bridge plate osteosynthesis has been shown to be a secure technique with good results for treating humeral shaft fractures. There is no good quality evidence advocating which method is more effective. This randomised controlled trial will be performed to investigate the effectiveness of surgical treatment of humeral shaft fractures with bridge plating in comparison with conservative treatment with functional brace. Methods/Design This randomised clinical trial aims to include 110 patients with humeral shaft fractures who will be allocated after randomisation to one of the two groups: bridge plate or functional brace. Surgical treatment will be performed according to technique described by Livani and Belangero using a narrow DCP plate. Non-operative management will consist of a functional brace for 6 weeks or until fracture consolidation. All patients will be included in the same rehabilitation program and will be followed up for 1 year after intervention. The primary outcome will be the DASH score after 6 months of intervention. As secondary outcomes, we will assess SF-36 questionnaire, treatment complications, Constant score, pain (Visual Analogue Scale) and radiographs. Discussion According to current evidence shown in a recent systematic review, this study is one of the first randomised controlled trials designed to compare two methods to treat humeral shaft fractures (functional brace and bridge plate surgery). Trial registration Current Controlled Trials: ISRCTN

  17. Study of the interaction between Ti-based osteosynthesis plates and the human body by XPS, SIMS and AES

    NASA Astrophysics Data System (ADS)

    Suba, Csongor; Kovács, Krisztina; Kiss, Gábor; Vida, György; Varga, Máté; Velich, Norbert; Kovács, Lajos; Kádár, Bence; Szabó, György

    2007-02-01

    Ti implants with surfaces modified by anodic and thermal oxidation were used to promote osteosynthesis. X-ray photoelectron spectroscopy, secondary ion mass spectroscopy and Auger electron spectroscopy were used to study the surface composition and the depth homogeneity of the implant materials before implantation and after removal from the patient (3 years later). The surface of the Ti implants was modified through anodic and thermal oxidation. The surface of the Ti implant before use is covered by a 200 nm thick TiO2 layer, with homogeneously distributed O at depth. During the formation of this TiO2 layer, phosphate, Ca and a small amount of C are incorporated into the oxide. Similarly to the main impurities in the base Ti metal (Cr and Fe), the Ca and C accumulate at the oxide/metal interface. Three years after the implantation, the binding state of the Ti in the oxide layer was unchanged. The base metal remained covered by TiO2, the outer surface of which was partially covered by a mainly C-containing layer of varying thickness. The increases in the Ca and P contents of the TiO2 layer during the 3 years in the human body can be explained by incorporation from the body. Clinically, no metallosis or allergic reactions were observed.

  18. A Novel Shape Memory Plate Osteosynthesis for Noninvasive Modulation of Fixation Stiffness in a Rabbit Tibia Osteotomy Model

    PubMed Central

    Müller, Christian W.; Pfeifer, Ronny; Meier, Karen; Decker, Sebastian; Reifenrath, Janin; Gösling, Thomas; Wesling, Volker; Krettek, Christian; Hurschler, Christof; Krämer, Manuel

    2015-01-01

    Nickel-titanium shape memory alloy (NiTi-SMA) implants might allow modulating fracture healing, changing their stiffness through alteration of both elastic modulus and cross-sectional shape by employing the shape memory effect (SME). Hypotheses: a novel NiTi-SMA plate stabilizes tibia osteotomies in rabbits. After noninvasive electromagnetic induction heating the alloy exhibits the SME and the plate changes towards higher stiffness (inverse dynamization) resulting in increased fixation stiffness and equal or better bony healing. In 14 rabbits, 1.0 mm tibia osteotomies were fixed with our experimental plate. Animals were randomised for control or induction heating at three weeks postoperatively. Repetitive X-ray imaging and in vivo measurements of bending stiffness were performed. After sacrifice at 8 weeks, macroscopic evaluation, µCT, and post mortem bending tests of the tibiae were carried out. One death and one early implant dislocation occurred. Following electromagnetic induction heating, radiographic and macroscopic changes of the implant proved successful SME activation. All osteotomies healed. In the treatment group, bending stiffness increased over time. Differences between groups were not significant. In conclusion, we demonstrated successful healing of rabbit tibia osteotomies using our novel NiTi-SMA plate. We demonstrated shape-changing SME in-vivo through transcutaneous electromagnetic induction heating. Thus, future orthopaedic implants could be modified without additional surgery. PMID:26167493

  19. Experimental study in order to assess the effects of limited periosteum stripping on the fracture healing and to compare osteosynthesis using plates and screws with intramedullary Kirschner wire fixation.

    PubMed

    Neagu, Tiberiu Paul; Enache, Valentin; Cocoloş, Ion; Ţigliş, Mirela; Cobilinschi, Cristian; Ţincu, Radu

    2016-01-01

    There are many studies that investigate indirect and direct fracture healing but few mention the effect of periosteum stripping on consolidation of fractures. Most of these studies use only one method of osteosynthesis for each group. Therefore, we reported a new developed murine model in order to assess if limited periosteum stripping influence significantly the quality of the fracture healing process by comparing two different osteosynthesis methods to reduce simultaneously bilateral femur fractures. We applied the experimental protocol for a number of 12 rats. We used plates and screws to reduce femoral osteotomy for the right hind limb and intramedullary Kirschner wire for the left hind limb. Clinical, radiological and histological assessments were made for a period of eight weeks. The absence of a healthy hind limb led to a slower healing process based on the histological findings and to implant failure based on radiological findings. In summary, complete fracture healing was not achieved during this experimental study. Therefore, we consider that future studies are needed for a better understanding of the effects of periosteum removal on the fracture healing process. PMID:27516016

  20. Understand, solve problems with ESP wide plate spacing

    SciTech Connect

    Grieco, G.J.

    1994-08-01

    Selecting the appropriate type of discharge electrode and the width of the channels formed by the collecting plates is critical to the performance of a high-efficiency electrostatic precipitator (ESP). These considerations may be biased toward a supplier's standard discharge electrode designs and the economic pressure to apply wide plate spacing, often, it has turned out, at the expense of the performance of the ESP. As with any system, a change in any one component will impact the performance of all other components. The trend toward wide plate spacings has not always resulted in parametric analysis of the effect on the rest of the components. Discharge electrode configuration, collecting plate spacing, field strength, current density, particulate size and resistivity, and dust loading must all be taken into consideration when optimum precipitator performance is sought. This article provides an understanding of the ESP precipitation process that can provide insights into the proper application of wide plate spacing and discharge-electrodes configuration as well as design changes that can be incorporated to improve performance.

  1. Fractures of the distal third of the humerus with palsy of the radial nerve: management using minimally-invasive percutaneous plate osteosynthesis.

    PubMed

    Livani, B; Belangero, W D; Castro de Medeiros, R

    2006-12-01

    Fractures of the distal third of the humerus may be complicated by complete lesions of the radial nerve which may be entrapped or compressed by bone fragments. Indirect reduction and internal fixation may result in a permanent nerve lesion. We describe the treatment of these lesions by insertion of a bridge plate using the minimally-invasive percutaneous technique. Six patients were operated on and showed complete functional recovery. Healing of the fractures occurred at a mean of 2.7 months (2 to 3) and complete neurological recovery by a mean of 2.3 months (1 to 5). In one patient infection occurred which resolved after removal of the implant. PMID:17159176

  2. Are allogenic or xenogenic screws and plates a reasonable alternative to alloplastic material for osteosynthesis--a histomorphological analysis in a dynamic system.

    PubMed

    Jacobsen, C; Obwegeser, J A

    2010-12-01

    Despite invention of titanium and resorbable screws and plates, still, one of the main challenges in bone fixation is the search for an ideal osteosynthetic material. Biomechanical properties, biocompatibility, and also cost effectiveness and clinical practicability are factors for the selection of a particular material. A promising alternative seems to be screws and plates made of bone. Recently, xenogenic bone pins and screws have been invented for use in joint surgery. In this study, screws made of allogenic sheep and xenogenic human bone were analyzed in a vital and dynamic sheep-model and compared to conventional titanium screws over a standard period of bone healing of 56 days with a constant applied extrusion force. Biomechanical analysis and histomorphological evaluation were performed. After 56 days of insertion xenogenic screws made of human bone showed significantly larger distance of extrusion of on average 173.8 μm compared to allogenic screws made of sheep bone of on average 27.8 and 29.95 μm of the titanium control group. Severe resorption processes with connective tissue interposition were found in the histomorphological analysis of the xenogenic screws in contrast to new bone formation and centripetal vascularization of the allogenic bone screw, as well as in processes of incorporation of the titanium control group. The study showed allogenic cortical bone screws as a substantial alternative to titanium screws with good biomechanical properties. In contrast to other reports a different result was shown for the xenogenic bone screws. They showed insufficient holding strength with confirmative histomorphological signs of degradation and insufficient osseointegration. Before common clinical use of xenogenic osteosynthetic material, further evaluation should be performed. PMID:20813368

  3. Solving the vibroacoustic equations of plates by minimization of error on a sample of observation points.

    PubMed

    Collery, Olivier; Guyader, Jean-Louis

    2010-03-01

    In the context of better understanding and predicting sound transmission through heterogeneous fluid-loaded aircraft structures, this paper presents a method of solving the vibroacoustic problem of plates. The present work considers fluid-structure coupling and is applied to simply supported rectangular plates excited mechanically. The proposed method is based on the minimization of the error of verification of the plate vibroacoustic equation of motion on a sample of points. From sampling comes an aliasing effect; this phenomenon is described and solved using a wavelet-based filter. The proposed approach is validated in presenting very accurate results of sound radiation immersed in heavy and light fluids. The fluid-structure interaction appears to be very well described avoiding time-consuming classical calculations of the modal radiation impedances. The focus is also put on different samplings to observe the aliasing effect. As perspectives sound radiation from a non-homogeneous plate is solved and compared with reference results proving all the power of this method.

  4. The value of ultrasound-assisted pinned resorbable osteosynthesis for cranial vault remodelling in craniosynostosis.

    PubMed

    Freudlsperger, Christian; Castrillon-Oberndorfer, Gregor; Baechli, Heidi; Hoffmann, Juergen; Mertens, Christian; Engel, Michael

    2014-07-01

    Resorbable osteosynthesis is a widespread tool in craniofacial surgery, however only a limited number of studies have focused on ultrasound-assisted pinned resorbable systems in the treatment of craniosynostosis. Thirty-eight children with various types of craniosynostosis including scaphocephaly, trigonocephaly, anterior and posterior plagiocephaly were treated using the Sonic Welding resorbable osteosynthesis system. All patients were evaluated for operation time, stability of the surgical results, rate of local infections and visibility or palpability of the osteosynthesis material in the follow-up ranging from 15 to 21 month. Mean operation time was not significantly higher compared to conventional osteosynthesis material and all remodelled cranial vaults showed immediate stability. Only one patient showed signs of an inflammatory skin reaction, which recovered spontaneously. The number of palpable or visible plates, respectively, increased during the first months with a maximum at 12 months (34 (89%) plates palpable, 26 (68%) plates visible). After this time point, the number decreased continuously until the end of the follow-up period at 21 months when 3 (20%) plates were palpable, 0 (0%) plates were visible). Ultrasound-assisted pinned resorbable systems seem to be a promising tool in craniofacial surgery providing a timesaving and stable osteosynthesis. An initial swelling of the plates during the first 12 months before the complete degradation might result in a palpable and visible bulge.

  5. Quasi-simultaneous interaction method for solving 2D boundary layer flows over plates and airfoils

    NASA Astrophysics Data System (ADS)

    Bijleveld, H. A.; Veldman, A. E. P.

    2012-11-01

    This paper studies unsteady 2D boundary layer flows over dented plates and a NACA 0012 airfoil. An inviscid flow is assumed to exist outside the boundary layer and is solved iteratively with the boundary layer flow together with the interaction method until a matching solution is achieved. Hereto a quasi-simultaneous interaction method is applied, in which the integral boundary layer equations are solved together with an interaction-law equation. The interaction-law equation is an approximation of the external flow and based on thin-airfoil theory. It is an algebraic relation between the velocity and displacement thickness. The interaction-law equation ensures that the eigenvalues of the system of equations do not have a sign change and that no singularities occur. Three numerical schemes are used to solve the boundary layer flow with the interaction method. These are: a standard scheme, a splitting method and a characteristics solver. All schemes use a finite difference discretization. The three schemes yield comparable results for the simulations carried out. The standard scheme is deviating most from the splitting and characteristics solvers. The results show that the eigenvalues remain positive, even in separation. As expected, the addition of the interaction-law equation prevents a sign change of the eigenvalues. The quasi-simultaneous interaction scheme is applicable to the three numerical schemes tested.

  6. Osteosynthesis system for vertebra arthrodesis

    DOEpatents

    Ameil, Marc; Huppert, Jean; Jermann, Jean-Louis; Marnay, Thierry

    2000-01-01

    An osteosynthesis system for vertebral arthrodesis, having at least one vertebral compression or distraction bar capable of extending over a portion at least of the rachis; at least one vertebral anchoring member having an end head with a spherical surface, an intermediate shank and a vertebral anchoring portion; and, associated with each anchoring member, a common support for receiving, coupling and immobilizing the vertebral anchoring member and the bar, the common support including a first concave housing for receiving the bar, a second concave housing, for receiving the spherical head, and a screwthreaded member, for immobilization of the bar and the anchoring member on the support, the immobilization member having at least one nut which is screwed onto a screwthreaded portion of the support. The first housing is disposed to the exterior of the screwthreaded portion of the support and is open laterally and upwardly, in opposite relationship to the rachis, so that the bar is immobilized by a peripheral portion of the nut.

  7. Resorbable continuous-fibre reinforced polymers for osteosynthesis.

    PubMed

    Dauner, M; Planck, H; Caramaro, L; Missirlis, Y; Panagiotopoulos, E

    1998-03-01

    Four institutes from three countries in the European Union have collaborated under the BRITE-EURAM framework programme for the development of processing technologies for resorbable osteosynthesis devices. The devices should be continuous-fibre reinforced, and the technology should offer the possibility of orienting the fibres in the main trajectories. Poly-L-lactide and poly-L-DL-lactides have been synthesized for reinforcement fibres and matrix material, respectively. Melt-spun P-L-LA fibres of a strength of 800 MPa have been embedded in an amorphous P-L-DL-LA 70 : 30 matrix by compression moulding. Ethyleneoxide sterilized samples have been tested in vitro and in vivo. A satisfying bending modulus has been reached (6 GPa). Yet with 50% strength retention after ten weeks, fast degradation occurred that could be related to residual monomers. By this fast degradation 70% resorption after one year could be observed in the non-functional animal studies in rabbits. There was only a mild inflammatory reaction, which confirmed the good biocompatibility of the materials even during the resorption period. Further effort has to concentrate on the reduction of initial monomer content. The great advantage of the processing method to orient fibres in the device will be utilized in prototype samples, e.g. an osteosynthesis plate with fixation holes.

  8. Solving TEAM problem 8 (slot in a plate) on a PC with ELEKTRA

    SciTech Connect

    Turner, L.R.

    1996-05-01

    This note presents the solution of TEAM Problem 8, a problem in nondestructive testing with eddy currents. A differential probe consisting of two thin coils 15 mm apart produces a signal. The computation used a fairly coarse three-dimensional mesh: fewer than 8000 elements, fewer than 20,000 equations. Subtracting the signal from a differential probe over a plate with no flaw from the signal over a plate with a flaw eliminated the effects of mesh coarseness. Even though this process requires taking the difference of two already small differences, the solution for the effect of the flaw agrees well with the three sets of experimental results as the results agree with each other. With the use of this process, the results do not show the effects of the edge of the plate that complicate the experimental results. On a 90-MHz Pentium PC, each position of the probe required a 10-minute solution for the case with the flaw and another 10-minute solution without the flaw.

  9. Miniplate osteosynthesis of fractures of the edentulous mandible.

    PubMed

    Mugino, Hiroshi; Takagi, Shinji; Oya, Ryoichi; Nakamura, Syoichi; Ikemura, Kunio

    2005-12-01

    This study was performed to analyze treatment of fractures of the edentulous mandible and to discuss this method in relation to the mandibular height at the fracture site. Fifteen fracture sites in 11 patients with an edentulous mandible were retrospectively examined. These fractures were located: nine fractures in the mandibular body, three in the paramedian region, and three in the mandibular angle. Fractures in a mandible measuring more than 10 mm in the vertical height were treated with one miniplate. Fractures in an extremely atrophic mandible with 10 mm or less were treated using one or two miniplates, also using a modified Champy plate with 1.3 mm in thickness. A mandibular fracture with a height of 5 mm was treated with a combination of a microplate on the buccal side and a miniplate on the inferior border of the mandible with additional direct circumferential wiring. Oblique or splitting fractures were treated with direct circumferential wiring or a Herbert screw, at one fracture site each, respectively. Complications, including infection, fibrous union, nonunion and trismus, were not seen. In one patient, hypesthesia of the lower lip was, however, persistent 1 month after surgery. Miniplate osteosynthesis is the less invasive treatment, and it is suitable for fractures of the atrophic edentulous mandible, except for comminuted or defect fractures. To obtain stable fixation in severely atrophic mandibles, we need to consider the use of two miniplates or a combination with microplates. PMID:16311742

  10. Reinforcement of osteosynthesis screws with brushite cement.

    PubMed

    Van Landuyt, P; Peter, B; Beluze, L; Lemaître, J

    1999-08-01

    The fixation of osteosynthesis screws remains a severe problem for fracture repair among osteoporotic patients. Polymethyl-methacrylate (PMMA) is routinely used to improve screw fixation, but this material has well-known drawbacks such as monomer toxicity, exothermic polymerization, and nonresorbability. Calcium phosphate cements have been developed for several years. Among these new bone substitution materials, brushite cements have the advantage of being injectable and resorbable. The aim of this study is to assess the reinforcement of osteosynthesis screws with brushite cement. Polyurethane foams, whose density is close to that of cancellous bone, were used as bone model. A hole was tapped in a foam sample, then brushite cement was injected. Trabecular osteosynthesis screws were inserted. After 24 h of aging in water, the stripping force was measured by a pull-out test. Screws (4.0 and 6.5 mm diameter) and two foam densities (0.14 and 0.28 g/cm3) were compared. Cements with varying solid/liquid ratios and xanthan contents were used in order to obtain the best screw reinforcement. During the pull-out test, the stripping force first increases to a maximum, then drops to a steady-state value until complete screw extraction. Both maximum force and plateau value increase drastically in the presence of cement. The highest stripping force is observed for 6.5-mm screws reinforced with cement in low-density foams. In this case, the stripping force is multiplied by 3.3 in the presence of cement. In a second experiment, cements with solid/liquid ratio ranging from 2.0 to 3.5 g/mL were used with 6.5-mm diameter screws. In some compositions, xanthan was added to improve injectability. The best results were obtained with 2.5 g/mL cement containing xanthan and with 3.0 g/mL cements without xanthan. A 0.9-kN maximal stripping force was observed with nonreinforced screws, while 1.9 kN was reached with reinforced screws. These first results are very promising regarding screw

  11. Osteosynthesis with Rush's double nail by the "Eiffel Tower" method in pseudarthrosis impacted in good position and retarded union.

    PubMed

    Zinghi, G F; Lanfranchi, R

    1980-04-01

    The "Eiffel Tower" method of nailing has not attracted the interest in Italy that it deserves, both because its utilisaton in fractures is difficult when closed reduction of the fragments is difficult, and because the attention of surgeons has been progressively directed towards osteosynthesis by open reduction. Our experience over many years, however, has convinced us that, in the diaphysis, only the intramedullary nail can provide the quick recovery that is not always forthcoming in the case of plating. We need only think of comminuted fractures, where the possible necrosis of one or more fragments demands a certain amount of prudence in allowing direct weight bearing. Therefore, in adopting the double Rush system, we extended its application to the intramedullary osteosynthesis of metaphyseal fractures. It was a short step from this to the surgical treatment of pseudarthrosis impacted in good position or retarded union, the results of which were encouraging, as demonstrated by the eighty-one cases reported in this paper.

  12. The influence of bone density and anisotropy in finite element models of distal radius fracture osteosynthesis: Evaluations and comparison to experiments.

    PubMed

    Synek, A; Chevalier, Y; Baumbach, S F; Pahr, D H

    2015-11-26

    Continuum-level finite element (FE) models can be used to analyze and improve osteosynthesis procedures for distal radius fractures (DRF) from a biomechanical point of view. However, previous models oversimplified the bone material and lacked thorough experimental validation. The goal of this study was to assess the influence of local bone density and anisotropy in FE models of DRF osteosynthesis for predictions of axial stiffness, implant plate stresses, and screw loads. Experiments and FE analysis were conducted in 25 fresh frozen cadaveric radii with DRFs treated by volar locking plate osteosynthesis. Specimen specific geometries were captured using clinical quantitative CT (QCT) scans of the prepared samples. Local bone material properties were computed based on high resolution CT (HR-pQCT) scans of the intact radii. The axial stiffness and individual screw loads were evaluated in FE models, with (1) orthotropic inhomogeneous (OrthoInhom), (2) isotropic inhomogeneous (IsoInhom), and (3) isotropic homogeneous (IsoHom) bone material and compared to the experimental axial stiffness and screw-plate interface failures. FE simulated and experimental axial stiffness correlated significantly (p<0.0001) for all three model types. The coefficient of determination was similar for OrthoInhom (R(2)=0.807) and IsoInhom (R(2)=0.816) models but considerably lower for IsoHom models (R(2)=0.500). The peak screw loads were in qualitative agreement with experimental screw-plate interface failure. Individual loads and implant plate stresses of IsoHom models differed significantly (p<0.05) from OrthoInhom and IsoInhom models. In conclusion, including local bone density in FE models of DRF osteosynthesis is essential whereas local bone anisotropy hardly effects the models׳ predictive abilities.

  13. Holographic Interferometry Applications In External Osteosynthesis

    NASA Astrophysics Data System (ADS)

    Jacquot, P.; Rastogi, P. K.; Pflug, L.

    1985-08-01

    In order to maintain fragments of fractured bones in a state of immobilization, the use of an external rigid frame has proved to be very advantageous. Confronted by contradictory requirements, the conception of external fixation has, however, been a difficult task. The present paper aims to show, through three examples of varied bearings, the interest of holographic interferometry in external osteosynthesis. The first example deals with the mechanical behavior of a key element of the fixation device the ball joint submitted to realistic loads. The last two examples compare two models of ball joints as to their characteristics of rigidity and of resistance to slipping. Whereas in the former case holographic interferometry primarily fulfills the function of a prelude to the modelization work, in the latter cases it serves to formulate an engineering diagnostic. The findings relate to the remarkable elastic behavior of the ball joint, to the effectiveness of a lightened bowl design, and to the fact that cousin models may behave quite differently as to their resistance to slipping rotations of the bar. In comparison with other experimental methods, holographic interferometry appears to be very competitive and result-oriented and, as such, is expected to multiply applications in similar evaluation tasks.

  14. Pediatric craniofacial osteosynthesis and distraction using an ultrasonic-assisted pinned resorbable system: a prospective report with a minimum 30 months' follow-up.

    PubMed

    Arnaud, Eric; Renier, Dominique

    2009-11-01

    Resorbable osteosynthesis is an important tool in pediatric craniofacial surgery. A prospective clinical study was carried out to evaluate the Sonic Welding resorbable osteosynthesis system. Twenty pediatric patients with craniosynostosis were operated on for craniofacial reconstruction. The techniques used were the same than usual (fronto-orbital remodeling or advancement). During the process of osteosynthesis, similar resorbable miniplates were used, but for fixation, only 2 steps were necessary (drilling and welding), tapping being unnecessary. Clinically, the hold of the pins in the bone seemed stronger, and less-than-usual osteosynthesis materials were necessary. Clearly, the pins were able to hold in a very thin bone in which no screws could hold. Subjectively, the satisfaction of the surgeon was greater owing to the avoidance of the tapping step. On follow-up, resorption took place with an initial swelling effect, like with another pure polylactic acid material. The good resistance of pins suggests that, in such a system, the resorbable plate becomes the weak point. PMID:19881368

  15. Pediatric craniofacial osteosynthesis and distraction using an ultrasonic-assisted pinned resorbable system: a prospective report with a minimum 30 months' follow-up.

    PubMed

    Arnaud, Eric; Renier, Dominique

    2009-11-01

    Resorbable osteosynthesis is an important tool in pediatric craniofacial surgery. A prospective clinical study was carried out to evaluate the Sonic Welding resorbable osteosynthesis system. Twenty pediatric patients with craniosynostosis were operated on for craniofacial reconstruction. The techniques used were the same than usual (fronto-orbital remodeling or advancement). During the process of osteosynthesis, similar resorbable miniplates were used, but for fixation, only 2 steps were necessary (drilling and welding), tapping being unnecessary. Clinically, the hold of the pins in the bone seemed stronger, and less-than-usual osteosynthesis materials were necessary. Clearly, the pins were able to hold in a very thin bone in which no screws could hold. Subjectively, the satisfaction of the surgeon was greater owing to the avoidance of the tapping step. On follow-up, resorption took place with an initial swelling effect, like with another pure polylactic acid material. The good resistance of pins suggests that, in such a system, the resorbable plate becomes the weak point.

  16. Mechanical properties of Indonesian-made narrow dynamic compression plate.

    PubMed

    Dewo, P; van der Houwen, E B; Sharma, P K; Magetsari, R; Bor, T C; Vargas-Llona, L D; van Horn, J R; Busscher, H J; Verkerke, G J

    2012-09-01

    Osteosynthesis plates are clinically used to fixate and position a fractured bone. They should have the ability to withstand cyclic loads produced by muscle contractions and total body weight. The very high demand for osteosynthesis plates in developing countries in general and in Indonesia in particular necessitates the utilisation of local products. In this paper, we investigated the mechanical properties, i.e. proportional limit and fatigue strength of Indonesian-made Narrow Dynamic Compression Plates (Narrow DCP) as one of the most frequently used osteosynthesis plates, in comparison to the European AO standard plate, and its relationship to geometry, micro structural features and surface defects of the plates. All Indonesian-made plates appeared to be weaker than the standard Narrow DCP because they consistently failed at lower stresses. Surface defects did not play a major role in this, although the polishing of the Indonesian Narrow DCP was found to be poor. The standard plate showed indications of cold deformation from the production process in contrast to the Indonesian plates, which might be the first reason for the differences in strength. This is confirmed by hardness measurements. A second reason could be the use of an inferior version of stainless steel. The Indonesian plates showed lower mechanical behaviour compared to the AO-plates. These findings could initiate the development of improved Indonesian manufactured DCP-plates with properties comparable to commonly used plates, such as the standard European AO-plates.

  17. Finite element analysis of osteosynthesis screw fixation in the bone stock: an appropriate method for automatic screw modelling.

    PubMed

    Wieding, Jan; Souffrant, Robert; Fritsche, Andreas; Mittelmeier, Wolfram; Bader, Rainer

    2012-01-01

    The use of finite element analysis (FEA) has grown to a more and more important method in the field of biomedical engineering and biomechanics. Although increased computational performance allows new ways to generate more complex biomechanical models, in the area of orthopaedic surgery, solid modelling of screws and drill holes represent a limitation of their use for individual cases and an increase of computational costs. To cope with these requirements, different methods for numerical screw modelling have therefore been investigated to improve its application diversity. Exemplarily, fixation was performed for stabilization of a large segmental femoral bone defect by an osteosynthesis plate. Three different numerical modelling techniques for implant fixation were used in this study, i.e. without screw modelling, screws as solid elements as well as screws as structural elements. The latter one offers the possibility to implement automatically generated screws with variable geometry on arbitrary FE models. Structural screws were parametrically generated by a Python script for the automatic generation in the FE-software Abaqus/CAE on both a tetrahedral and a hexahedral meshed femur. Accuracy of the FE models was confirmed by experimental testing using a composite femur with a segmental defect and an identical osteosynthesis plate for primary stabilisation with titanium screws. Both deflection of the femoral head and the gap alteration were measured with an optical measuring system with an accuracy of approximately 3 µm. For both screw modelling techniques a sufficient correlation of approximately 95% between numerical and experimental analysis was found. Furthermore, using structural elements for screw modelling the computational time could be reduced by 85% using hexahedral elements instead of tetrahedral elements for femur meshing. The automatically generated screw modelling offers a realistic simulation of the osteosynthesis fixation with screws in the adjacent

  18. Finite Element Analysis of Osteosynthesis Screw Fixation in the Bone Stock: An Appropriate Method for Automatic Screw Modelling

    PubMed Central

    Wieding, Jan; Souffrant, Robert; Fritsche, Andreas; Mittelmeier, Wolfram; Bader, Rainer

    2012-01-01

    The use of finite element analysis (FEA) has grown to a more and more important method in the field of biomedical engineering and biomechanics. Although increased computational performance allows new ways to generate more complex biomechanical models, in the area of orthopaedic surgery, solid modelling of screws and drill holes represent a limitation of their use for individual cases and an increase of computational costs. To cope with these requirements, different methods for numerical screw modelling have therefore been investigated to improve its application diversity. Exemplarily, fixation was performed for stabilization of a large segmental femoral bone defect by an osteosynthesis plate. Three different numerical modelling techniques for implant fixation were used in this study, i.e. without screw modelling, screws as solid elements as well as screws as structural elements. The latter one offers the possibility to implement automatically generated screws with variable geometry on arbitrary FE models. Structural screws were parametrically generated by a Python script for the automatic generation in the FE-software Abaqus/CAE on both a tetrahedral and a hexahedral meshed femur. Accuracy of the FE models was confirmed by experimental testing using a composite femur with a segmental defect and an identical osteosynthesis plate for primary stabilisation with titanium screws. Both deflection of the femoral head and the gap alteration were measured with an optical measuring system with an accuracy of approximately 3 µm. For both screw modelling techniques a sufficient correlation of approximately 95% between numerical and experimental analysis was found. Furthermore, using structural elements for screw modelling the computational time could be reduced by 85% using hexahedral elements instead of tetrahedral elements for femur meshing. The automatically generated screw modelling offers a realistic simulation of the osteosynthesis fixation with screws in the adjacent

  19. Implementation of the Bacillus cereus microbiological plate used for the screening of tetracyclines in raw milk samples with STAR protocol - the problem with false-negative results solved.

    PubMed

    Raspor Lainšček, P; Biasizzo, M; Henigman, U; Dolenc, J; Kirbiš, A

    2014-01-01

    In antibiotic residue analyses the first step of screening is just as important as the following steps. Screening methods need to be quick and inexpensive, but above all sensitive enough to detect the antibiotic residue at or below the maximum residue limit (MRL). In the case of a positive result, the next step is conducted and further methods are used for confirmation. MRLs stated in European Union Regulation 37/2010 for tetracyclines in raw milk are: 100 µg kg(-1) for tetracycline, 100 µg kg(-1) for oxytetracycline, 100 µg kg(-1) for chlortetracycline and no limit for doxycycline because it is prohibited for use in animals from which milk is produced for human consumption. The current five-plate microbiological screening method for the detection of antibiotic residues in raw milk was found to be simple and inexpensive, but not specific, sensitive and reliable enough to detect tetracycline at MRL in routine raw milk screening procedures. Spiking samples with tetracycline at the MRL level and applying them on Bacillus cereus ATCC 11778 microbiological plates often gave false-negative results, indicating that tetracyclines may have to be inactivated or masked. Tetracyclines seem to bind to a certain component in milk. Consequently, when applying samples to the B. cereus microbiological plate the antibiotic cannot inhibit the growth of B. cereus which disables the formation of inhibition zones on the test plate. After adding the appropriate amount of citric acid into the milk samples, we solved the problem of false-negative results. During the validation 79 samples of milk were spiked with tetracyclines at different concentrations: 100 µg kg(-1) for tetracycline, 100 µg kg(-1) for oxytetracycline, 80 µg kg(-1) for chlortetracycline and 30 µg kg(-1) for doxycycline. Concentrations used in the validation matched the requirements for MRLs (they were either at or below the MRLs) stated in European Union Regulation 37/2010. The sensitivity of the validation was 100%.

  20. Aseptic nonunion of the tibia treated by intramedullary osteosynthesis.

    PubMed

    Gualdrini, G; Rollo, G; Montanari, A; Zinghi, G F

    1996-01-01

    The authors report 52 cases of aseptic nonunion of the tibia treated by intramedullary osteosynthesis. The means of synthesis used were the Küntscher nail, the Eiffel Tower Rush nail, and the Grosse-Kempf nail. Which means of synthesis was used depended on the site and the features of the nonunion. Healing occurred in all of the cases after an average of 5 months. Mean follow-up was 4.5 years.

  1. [METHOD OF OSTEOSYNTHESIS OF SUPRACONDULAR FRACTURES OF THE HUMERUS].

    PubMed

    Neverov, V A; Chernyaev, S N; Shinkarenko, D V

    2015-01-01

    A treatment of fractures of distal metadiaphysis of the humeral bone remains an actual problem of modern traumatology at present time. This is associated with immediate proximity of the radial nerve and risk of iatrogenic injury in external fixation, presence of short distal fragment, comminuted nature of fracture, complexity of treatment method selection, need of extensible approach. Biomechanical features of different fixators were analyzed in consideration of presence of short distal fragment, traumatic of. external fixation and risk of iatrogenic injury of the nerve. The authors suggested the method of osteosynthesis of the humerus by using blocking osteosynthesis with preliminary extension of intra-medullary canal of distal fragment for obtaining stable osteosynthesis (priority No 2014105323 from 14.02.2014). The proposed method allowed avoiding the iatrogenic neuropathy of the radial nerve, providing the stability of fixation higher, than in case of external fixation. It excludes the need of external immobilization and combines the period of bony union with the period of rehabilitation and socially integrates the patient in minimal terms.

  2. Supraintercondylar fractures of the humerus--treatment by the Vigliani osteosynthesis.

    PubMed

    Fama, G

    1987-03-01

    Nineteen cases of supraintercondylar fractures of the humerus treated by the Vigliani osteosynthesis technique are described. This consists of wide transolecranon exposure of the fracture, stabilisation of the epiphyseal fragments with a transcondylar screw, and of the metaphyseo-epiphyseal junction with two condylo-diaphyseal "Eiffel Tower" Kirschner wires. The ulnar nerve is transposed anteriorly and the operation is carried out early in order to prevent neural disturbances and intra and/or periarticular ossification. The results confirm the validity of this method, which respects the delicate structure of this part of the humerus. Postoperative plaster is necessary as an indispensable complement to "minimum" osteosynthesis but this is quite free from risk. The importance of careful and gradual mobilisation of the elbow is also confirmed. Finally, this method combines the advantages of stable osteosynthesis in compression (screw and nut) at the epiphyseal site, with those of elastic osteosynthesis (Kirschner wires) at the metaphyseo-epiphyseal junction.

  3. Minimal Invasive Percutaneous Osteosynthesis for Elderly Valgus Impacted Proximal Humeral Fractures with the PHILOS.

    PubMed

    Chen, Hang; Hu, Xiaochuan; Tang, Haochen; Yang, Guoyong; Xiang, Ming

    2015-01-01

    There is a growing concern about elderly valgus impacted proximal humeral fractures. The aim of this study was to evaluate the treatment and clinical outcomes following minimal invasive percutaneous plate osteosynthesis (MIPPO) with the proximal humeral internal locking system (PHILOS) for the treatment of elderly valgus impacted proximal humeral fracture. Between May 2008 and May 2012, 27 patients (average age 67.3, range 61-74) with valgus impacted proximal humeral fractures were enrolled in the study. The patients were treated with MIPPO using PHILOS-plate through the anterolateral delta-splitting approach. Rehabilitation exercises were done gradually. The NEER score and Constant-Murley score were used to evaluate shoulder function. All the patients were followed up by routine radiological imaging and clinical examination. There were 15 cases of II-part greater tuberosity fractures, 10 cases of III-part greater tuberosity fractures, and 2 cases of IV-part fractures according to the NEER classification. The surgery was successful in all patients with an average follow-up of 20.8 (range: 11-34) months. The fractures united in an average of 7.2 (6-14) weeks without implant loosening. According to NEER score, there were 17 excellent, 7 satisfactory, 2 unsatisfactory, and 1 poor. The mean Constant-Murley score was 89.4 ± 4.35. No complication including axillary nerve damage, postoperative nerve or vessel damage, infections, DVT, or death was observed. In conclusion, the MIPPO technique with the PHILOS through the anterolateral delta-splitting approach seems to be a safe and easy treatment for elderly valgus impacted proximal humeral fractures. A case-control study and longer follow-up time are needed.

  4. Minimal Invasive Percutaneous Osteosynthesis for Elderly Valgus Impacted Proximal Humeral Fractures with the PHILOS

    PubMed Central

    Chen, Hang; Hu, Xiaochuan; Tang, Haochen; Yang, Guoyong; Xiang, Ming

    2015-01-01

    There is a growing concern about elderly valgus impacted proximal humeral fractures. The aim of this study was to evaluate the treatment and clinical outcomes following minimal invasive percutaneous plate osteosynthesis (MIPPO) with the proximal humeral internal locking system (PHILOS) for the treatment of elderly valgus impacted proximal humeral fracture. Between May 2008 and May 2012, 27 patients (average age 67.3, range 61–74) with valgus impacted proximal humeral fractures were enrolled in the study. The patients were treated with MIPPO using PHILOS-plate through the anterolateral delta-splitting approach. Rehabilitation exercises were done gradually. The NEER score and Constant-Murley score were used to evaluate shoulder function. All the patients were followed up by routine radiological imaging and clinical examination. There were 15 cases of II-part greater tuberosity fractures, 10 cases of III-part greater tuberosity fractures, and 2 cases of IV-part fractures according to the NEER classification. The surgery was successful in all patients with an average follow-up of 20.8 (range: 11–34) months. The fractures united in an average of 7.2 (6–14) weeks without implant loosening. According to NEER score, there were 17 excellent, 7 satisfactory, 2 unsatisfactory, and 1 poor. The mean Constant-Murley score was 89.4 ± 4.35. No complication including axillary nerve damage, postoperative nerve or vessel damage, infections, DVT, or death was observed. In conclusion, the MIPPO technique with the PHILOS through the anterolateral delta-splitting approach seems to be a safe and easy treatment for elderly valgus impacted proximal humeral fractures. A case-control study and longer follow-up time are needed. PMID:26693491

  5. Comparison of two-transsacral-screw fixation versus triangular osteosynthesis for transforaminal sacral fractures.

    PubMed

    Min, Kyong S; Zamorano, David P; Wahba, George M; Garcia, Ivan; Bhatia, Nitin; Lee, Thay Q

    2014-09-01

    Transforaminal pelvic fractures are high-energy injuries that are translationally and rotationally unstable. This study compared the biomechanical stability of triangular osteosynthesis vs 2-transsacral-screw fixation in the repair of a transforaminal pelvic fracture model. A transforaminal fracture model was created in 10 cadaveric lumbopelvic specimens. Five of the specimens were stabilized with triangular osteosynthesis, which consisted of unilateral L5-to-ilium lumbopelvic fixation and ipsilateral iliosacral screw fixation. The remaining 5 were stabilized with a 2-transsacral-screw fixation technique that consisted of 2 transsacral screws inserted across S1. All specimens were loaded cyclically and then loaded to failure. Translation and rotation were measured using the MicroScribe 3D digitizing system (Revware Inc, Raleigh, North Carolina). The 2-transsacral-screw group showed significantly greater stiffness than the triangular osteosynthesis group (2-transsacral-screw group, 248.7 N/mm [standard deviation, 73.9]; triangular osteosynthesis group, 125.0 N/mm [standard deviation, 66.9]; P=.02); however, ultimate load and rotational stiffness were not statistically significant. Compared with triangular osteosynthesis fixation, the use of 2 transsacral screws provides a comparable biomechanical stability profile in both translation and rotation. This newly revised 2-transsacral-screw construct offers the traumatologist an alternative method of repair for vertical shear fractures that provides biplanar stability. It also offers the advantage of percutaneous placement in either the prone or supine position.

  6. An alternative method of osteosynthesis for distal humeral shaft fractures.

    PubMed

    Levy, Jonathan C; Kalandiak, Steven P; Hutson, James J; Zych, Gregory

    2005-01-01

    Treatment of extra-articular distal humerus shaft fractures with plating techniques is often difficult, as traditional centrally located posterior plates often encroach on the olecranon fossa, limiting distal osseous fixation. The use of a modified Synthes Lateral Tibial Head Buttress Plate (Synthes, Paoli, PA) allows for a centrally placed posterior plating of the humeral shaft that angles anatomically along the lateral column to treat far distal humeral shaft fractures. Fifteen patients treated in this manner were followed to radiographic and clinical union. There were no cases of instrumentation failure or loss of reduction.

  7. The concept of locking plates.

    PubMed

    Cronier, P; Pietu, G; Dujardin, C; Bigorre, N; Ducellier, F; Gerard, R

    2010-05-01

    After a short historical review of locking bone plates since their inception more than a century ago to the success of the concept less than 15 years ago with today's plates, the authors present the main locking mechanisms in use. In the two broad categories - plates with fixed angulation and those with variable angulation - the screw head is locked in the plate with a locknut by screwing in a threaded chamber on the plate or by screwing through an adapted ring. The authors then provide a concrete explanation, based on simple mechanical models, of the fundamental differences between conventional bone plates and locking plates and why a locking screw system presents greater resistance at disassembly, detailing the role played by the position and number of screws. The advantages of epiphyseal fixation are then discussed, including in cases of mediocre-quality bone. For teaching purposes, the authors also present assembly with an apple fixed with five locking screws withstanding a 47-kg axial load with no resulting disassembly. The principles of plate placement are detailed for both the epiphysis and diaphysis, including the number and position of screws and respect of the soft tissues, with the greatest success assured by the minimally invasive and even percutaneous techniques. The authors then present the advantages of locking plates in fixation of periprosthetic fractures where conventional osteosynthesis often encounters limited success. Based on simplified theoretical cases, the economic impact in France of this type of implant is discussed, showing that on average it accounts for less than 10% of the overall cost of this pathology to society. Finally, the possible problems of material ablation are discussed as well as the means to remediate these problems.

  8. NASA Solve

    NASA Video Gallery

    NASA Solve lists opportunities available to the general public to contribute to solving tough problems related to NASA’s mission through challenges, prize competitions, and crowdsourcing activities...

  9. Posterior osteosynthesis of a spontaneous bilateral pedicle fracture of the lumbar spine.

    PubMed

    Han, Sang-Hyun; Hyun, Seung-Jae; Jahng, Tae-Ahn; Kim, Ki-Jeong

    2016-03-01

    Spontaneous bilateral pedicle fractures of the lumbar spine are rare, and an optimal surgical treatment has not been suggested. The authors report the case of a 50-year-old woman who presented with low-back pain and right leg radiating pain of 1 year's duration. Radiological studies revealed a spontaneous bilateral pedicle fracture of L-5. All efforts at conservative treatment failed, and the patient underwent surgery for osteosynthesis of the fractured pedicle using bilateral pedicle screws connected with a bent rod. Her low-back and right leg pain were relieved postoperatively. A CT scan performed 3 months postoperatively revealed the disappearance of the pedicle fracture gap and presence of newly formed bony trabeculation. In rare cases of spontaneous bilateral pedicle fracture of the lumbar spine, osteosynthesis of the fractured pedicle using bilateral pedicle screws and a bent rod is a motion-preserving technique that may be an effective option when conservative management has failed.

  10. [Kinesitherapy in the early postoperative period following intramedullary osteosynthesis of tibial fractures].

    PubMed

    Pavlov, D V; Vorob'ev, A V; Shimbaretskiĭ, A N; Komkova, O V

    2010-01-01

    A program of postoperative kinesitherapy oriented to normalize the muscular force of the shin, reduce the time needed to restore the weight-bearing function of the affected leg, and treat pain syndrome has been developed for the patients presenting with fractures, nonunions, and pseudoarthrosis of the tibia that were treated using intramedullary osteosynthesis. The efficacy of the program was evaluated in terms of restoration of the muscular force in the shin and improvement of microcirculation in the affected region. PMID:21089206

  11. [Assessment of the results of rehabilitation treatment after osteosynthesis of femoral trochanter fractures with Gamma nails].

    PubMed

    Kotela, Paweł; Bednarenko, Marcin; Kotela, Ireneusz

    2010-01-01

    The work presents the results of the rehabilitation after osteosynthesis of femoral trochanter fractures with the Gamma nails. Femoral trochanter fractures usually affect the elderly and senile patients, which require the use of appropriate methods of operation as well as intense rehabilitation. Early and intense post-operational management, based on physiotherapy has advantageous effects on the process of mobilization of the patients. In the majority of them it allows to regain the pre-traumatic ability, mobility and activity. PMID:20684340

  12. Radial shaft stress fracture after internal fixation using a titanium plate.

    PubMed

    Nagoshi, Narihito; Yamanaka, Kazuyoshi; Sasaki, Takashi

    2015-05-20

    A 22-year-old man, a boxer, presented with acute right forearm pain after striking a punch mitt. The patient had sustained a diaphyseal fracture of the right radius 19 months previously and was treated by minimally invasive plate osteosynthesis using a titanium reconstruction plate. Radiography revealed stress fractures beneath a proximal screw hole of the plate. The forearm was protected in a splint for 6 weeks and the fracture healed. Titanium plates are superior to stainless steel plates, due to various properties of titanium including corrosion resistance and biocompatibility. Removal of such plates is not routinely performed in our hospital, but plate removal may be warranted for patients who actively participate in certain sports.

  13. Double Tension Band Osteosynthesis in Inter-Condylar Humeral Fractures

    PubMed Central

    Munde, Santosh Lakshmanrao; Bhatti, Mohmmed Javed; Siwach, R.C.; Gulia, Anil; Kundu, Z.S.; Bansal, Sanjeev; Middha, Sanjay

    2015-01-01

    Introduction Intercondylar humerus fractures are uncommon in orthopaedic practice. The treatment for the same has been described in the literature and include paragonal and orthogonal fixation by using plates. Tension band wiring as a treatment for the same is sparsely described in the literature. Aim To evaluate the effectiveness of "Double Tension Band wiring" method for the treatment of intercondylar fractures of humerus and compare the results with studies involving treatment with locked plates. Materials and Methods Twenty patients, all presenting with fresh fractures of the distal humerus, treated with double tension band wiring were retrospectively evaluated over a period of three years. Fractures were classified according to Jupiter classification of distal humeral fractures. There were 5 high T fractures, 13 low T fractures and 2 Y fractures. According to AO classification, all were C1 fractures. Average age of the patients was 56.20 years (32-70 years). There were 13 males and 07 females. Results Out of 20 cases treated with this method, rigid fixation and union was achieved in all of them. The average tourniquet time was 69 minutes with minimum of 50 minutes and maximum of 120 minutes. Radiological union was achieved at an average of 10.8 weeks (8-14weeks). Average range of motion was 104.5 degrees with maximum range of motion 120 degrees (10-130) and minimum of 70 degrees (30-100). Excellent or good results were obtained in 80% of the patients in our study. Conclusion Double tension band is a reliable, less demanding and cost effective method of fixation of intercondylar fractures of humerus. PMID:26816955

  14. Solving Problems.

    ERIC Educational Resources Information Center

    Hale, Norman; Lindelow, John

    Chapter 12 in a volume on school leadership, this chapter cites the work of several authorities concerning problem-solving or decision-making techniques based on the belief that group problem-solving effort is preferable to individual effort. The first technique, force-field analysis, is described as a means of dissecting complex problems into…

  15. [Assessment of mechanical complications of intramedullary osteosynthesis in trochanteric fractures of the femur in elderly people].

    PubMed

    Hładki, Waldemar; Bednarenko, Marcin; Kotela, Ireneusz

    2011-01-01

    Operational treatment of trochanteric fractures of the femur, independently of the applied connecting implant, carries the risk of various types of complications. In this paper the incidence of mechanical complications in performed osteosynthesis of trochanteric fractures of the femur was analyzed as well as the risk factors influencing them and their extent were assessed. The results showed statistically significant influence of the type of implant, the type of fracture and the patients' age. It has been proven that the use of Gamma nail decreases the risk of mechanical complications almost twofold in comparison with the Ender's posts, disregarding the type of trochanteric fracture of the femur. PMID:21751513

  16. Holographic Interferometry Applied To External Osteosynthesis : Comparative Analysis Of The Performances Of External Fixation Prototypes

    NASA Astrophysics Data System (ADS)

    Jacquot, Pierre; Rastogi, Pramod K.; Pflug, Leopold

    1983-10-01

    The use of external osteosynthesis in the healing and the management of fractured bones is in rapid progression. The method employs an external rigid frame which is mounted to keep the fractured bones in state of immobilisation by means of percutaneous transfixing pins traversing the bones. In this paper, holographic interferometry is used to investigate the mechanical behaviour of the ball-joint - a central element in the fixation frame - sub-jected to realistic loads. Besides, the work has permitted to compare several models of this piece (of comparable handiness) as to their characteristics of rigidity and of resistance to slipping.

  17. [Basic studies of ultrasonic surgery. IV. Osteosynthesis in bone welding using ultrasound].

    PubMed

    Müller, T; Wolf, E; Winckler, U; Wehner, W

    1982-07-01

    A conglomerate of homologous bone-chips and n-butyl-cyanoacrylate fixes the fragments in the ultrasonic osteosynthesis. The sound pressure leads to the forced penetration of the monomer into preformed gaps of the bone surface (Volkmann and Haversian canals) up to maximum 300 microns during the polymerisation forced by ultrasound. A toothing effect between the conglomerate and the cortex takes place in this way, this one leads to a higher mechanical resistance and to specialities in the regenerative process. The term welding is founded scientifically by the mechanism of the connecting formation. On the other hand the application of the ultrasound is sensible in order to force the polymerisation.

  18. Solving Quartics

    ERIC Educational Resources Information Center

    Kulkarni, R. G.

    2007-01-01

    A technique is presented, which is different from the well-known Ferrari's method, to solve a general quartic equation. Formulae for the four roots of quartic are derived. A numerical example verifies the formulae obtained.

  19. Intramedullary cement osteosynthesis (IMCO): a pilot study in sheep.

    PubMed

    Mirzasadeghi, Alireza; Narayanan, Sri Subanesh; Ng, Min Hwei; Sanaei, Reza; Cheng, Chen Hui; Bajuri, Mohd Yazid; Shukur, Mohammad Hassan

    2014-01-01

    The application of bone substitutes and cements has a long standing history in augmenting fractures as a complement to routine fracture fixation techniques. Nevertheless, such use is almost always in conjunction with definite means of fracture fixation such as intramedullary pins or bone plates. The idea of using biomaterials as the primary fixation bears the possibility of simultaneous fixation and bone enhancement. Intramedullary recruitment of bone cements is suggested in this study to achieve this goal. However, as the method needs primary testings in animal models before human implementation, and since the degree of ambulation is not predictable in animals, this pilot study only evaluates the outcomes regarding the feasibility and safety of this method in the presence of primary bone fixators. A number of two sheep were used in this study. Tibial transverse osteotomies were performed in both animals followed by external skeletal fixation. The medullary canals, which have already been prepared by removing the marrow through proximal and distal drill holes, were then injected with calcium phosphate cement (CPC). The outcomes were evaluated postoperatively by standard survey radiographs, morphology, histology and biomechanical testings. Healing processes appeared uncomplicated until week four where one bone fracture recurred due to external fixator failure. The results showed 56% and 48% cortical thickening, compared to the opposite site, in the fracture site and proximal and distal diaphyses respectively. This bone augmentative effect resulted in 264% increase in bending strength of the fracture site and 148% increase of the same value in the adjacent areas of diaphyses. In conclusion, IMCO, using CPC in tibia of sheep, is safe and biocompatible with bone physiology and healing. It possibly can carry the osteopromotive effect of the CPCs to provide a sustained source of bone augmentation throughout the diaphysis. Although the results must be considered

  20. Treatment of Midshaft Clavicle Fractures: Application of Local Autograft With Concurrent Plate Fixation.

    PubMed

    Slette, Erik L; Mikula, Jacob D; Turnbull, Travis Lee; Hackett, Thomas R

    2016-06-01

    Currently, open reduction-internal fixation using contoured plates or intramedullary nails is considered the standard operative treatment for midshaft clavicle fractures because of the immediate rigid stability provided by the fixation device. In addition, autologous iliac crest bone graft has proved to augment osteosynthesis during internal fixation of nonunion fractures through the release of osteogenic factors. The purpose of this article is to describe a surgical technique developed to reduce donor-site morbidity and improve functional and objective outcomes after open reduction-internal fixation with autologous bone graft placement through local autograft harvesting and concurrent plate fixation. PMID:27656378

  1. [Morphological peculiarities of consolidation of experimental mandible fractures by osteosynthesis using Kollapan and retabolil].

    PubMed

    Beriashvili, G K; Menabde, G T; Chikhladze, R T

    2006-07-01

    The Purpose of the research was to study in the experiment morphological particularities of mandible fracture consolidation by osteosynthesis using Kollapan and Retabolil. The experiments were carried out on sexually matured rabbits. In the first series of the experiments (the control group), mandibula bones fracture was prototyped lower, whereas bone fragments were fixed by miniplate. In the second series of the experiments (the study group) bone fragments were bolted by the above mentioned way but diastase between bone fragments was filled by Kollapan granules, containing klaforan, and animals were intramuscularly anabolic material (the retabolil 0.4 mg/kg). On the 3-d and 15-th days, as well as, after 1 and 2 months after operation observing all corresponding rules, animals were killed and patologico-anatomic study of jaw bone was carried out. The analysis of the results showed that in experimental animals both in the control and the study groups reparative regeneration of bone tissues runs with the formation of periosteum and intermedium regenerator, at the same time consolidation of the bone defect in the main group occurs earlier than in the control group. The Results of the studies point out that Retabolil under osteosynthesis is an osteoinductive material and Kollapan, having osteoinductive, osteoconductive, and osteoprotective characteristics, promotes speeding of the process of jaw bones fracture consolidation. PMID:16905861

  2. Plate motion

    SciTech Connect

    Gordon, R.G. )

    1991-01-01

    The motion of tectonic plates on the earth is characterized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the NUVEL-1 global model of current plate motions, diffuse plate boundaries and the oceanic lithosphere, the relation between plate motions and distributed deformations, accelerations and the steadiness of plate motions, the distribution of current Pacific-North America motion across western North America and its margin, plate reconstructions and their uncertainties, hotspots, and plate dynamics. A comprehensive bibliography is provided. 126 refs.

  3. [Problems in osteosynthesis of patella fractures with the AO tension belt and consequences for new implants. The XS nail].

    PubMed

    Gehr, J; Friedl, W

    2001-11-01

    The eccentric ventral AO tension belt system represents the standard therapy of fractures of the patella. This often leads to unsatisfying results. Relating to Klute and Meenen [10] and the results of our own retrospective study, expressed as a percentage, 5-34% (own results 12.4%) have extremely poor treatment outcome, 23-60% (39%) end in deficiencies of bending, and there are 51-79.5% (65.7%) with subjective complaints after patella osteosynthesis. The disadvantages due to the eccentric tension belt position and the impossibility of applying the tension belt directly to the bone surface are abolished with the development of the XS nail. Due to its central position, constant compression of the entire fracture surface is provided. This is valid for all tension-stressed fractures such as those of the patella and olecranon. In synthetic patellae [5] standardized stress testing with changing tension up to 500 Newton was carried out. The XS nail was compared with the AO tension belt osteosynthesis after osteotomy and osteosynthesis in synthetic patellae. The XS nail was superior to the tension belt for all tests and therefore can be applied to all types of fractures where tension stress exists. We repaired the first 15 patella fractures with the XS nail. In 13 of 15 cases, full load of the injured leg was possible (for stairs a plaster splint was used). The experimental patella tests and first clinical results with the XS nail osteosynthesis after patella fracture confirm the new type of osteosynthesis, and functional treatment with loading seems possible.

  4. Chemical and structural analyses of titanium plates retrieved from patients.

    PubMed

    Pinto, C M S A; Asprino, L; de Moraes, M

    2015-08-01

    The aim of this study was to evaluate the microscopic structure and chemical composition of titanium bone plates and screws retrieved from patients with a clinical indication and to relate the results to the clinical conditions associated with the removal of these devices. Osteosynthesis plates and screws retrieved from 30 patients between January 2010 and September 2013 were studied by metallographic, gas, and energy dispersive X-ray (EDX) analyses and the medical records of these patients were reviewed. Forty-eight plates and 238 screws were retrieved. The time elapsed between plate and screw insertion and removal ranged between 11 days and 10 years. Metallographic analysis revealed that all the plates were manufactured from commercially pure titanium (CP-Ti). The screw samples analyzed consisted of Ti-6Al-4V alloy, except four samples, which consisted of CP-Ti. Titanium plates studied by EDX analysis presented greater than 99.7% titanium by mass. On gas analysis of Ti-6Al-4V screws, three samples were outside the standard values. One CP-Ti screw sample and one plate sample also presented an oxygen analysis value above the standard. The results indicated that the physical properties and chemical compositions of the plates and screws did not correspond with the need to remove these devices or the time of retention.

  5. Minimally invasive plate osteosythesis of fractures of the radius and ulna in a primate.

    PubMed

    Tong, K; Guiot, L P

    2013-01-01

    A 25-year-old female mandrill (Mandrillus sphinx - a primate and part of the Old World monkey group) was presented with a mildly comminuted, diaphyseal, radial fracture associated with a transverse ulnar fracture. Minimally invasive plate osteosynthesis techniques were used to achieve fixation of both the radial and the ulnar fractures. First, closed fracture reduction was achieved with a distraction frame consisting of a motorized circular external skeletal fixator. Next, dual percutaneous radio-ulnar plating was performed using a 2.7 limited-contact dynamic compression plate on the cranial aspect of the radius and two stacked 2.0/2.7 veterinary cut-to-length plates on the lateral aspect of the ulna. Uncomplicated recovery was observed with a complete return to normal activity three months postoperatively. Fracture healing was documented at four weeks, clinical union at 14 weeks, and callus remodelling at 24 weeks postoperatively. This report demonstrates the feasibility of minimally invasive plate osteosynthesis in a primate and shows the adaptability of this technique across mammalian species. PMID:23708981

  6. Finite element modeling for development and optimization of a bone plate for mandibular fracture in dogs.

    PubMed

    Freitas, Elisângela P; Rahal, Sheila C; Gioso, Marco Antonio; Vulcano, Luiz Carlos; Shimano, Antonio Carlos; da Silva, Jorge Vicente Lopes; Noritomi, Pedro Y; El Warrak, Alexander O

    2010-01-01

    This study aimed to develop a plate to treat fractures of the mandibular body in dogs and to validate the project using finite elements and biomechanical essays. Mandible prototypes were produced with 10 oblique ventrorostral fractures (favorable) and 10 oblique ventrocaudal fractures (unfavorable). Three groups were established for each fracture type. Osteosynthesis with a pure titanium plate of double-arch geometry and blocked monocortical screws of free angulation were used. The mechanical resistance of the prototype with unfavorable fracture was lower than that of the favorable fracture. In both fractures, the deflection increased and the relative stiffness decreased proportionally to the diminishing screw number The finite element analysis validated this plate study, since the maximum tension concentration observed on the plate was lower than the resistance limit tension admitted by the titanium. In conclusion, the double-arch geometry plate fixed with blocked monocortical screws has sufficient resistance to stabilize oblique fractures, without compromising mandibular dental or neurovascular structures. PMID:21322428

  7. Fixation of zygomatic and mandibular fractures with biodegradable plates

    PubMed Central

    Degala, Saikrishna; Shetty, Sujeeth; Ramya, S

    2013-01-01

    Context: In this prospective study, 13 randomly selected patients underwent treatment for zygomatic–complex fractures (2 site fractures) and mandibular fractures using 1.5 / 2 / 2.5-mm INION CPS biodegradable plates and screws. Aims: To assess the fixation of zygomatic-complex and mandibular fractures with biodegradable copolymer osteosynthesis system. Materials and Methods: In randomly selected 13 patients, zygomatic-complex and mandibular fractures were plated using resorbable plates and screws using Champy's principle. All the cases were evaluated clinically and radiologically for the type of fracture, need for the intermaxillary fixation (IMF) and its duration, duration of surgery, fixation at operation, state of reduction at operation, state of bone union after operation, anatomic reduction, paresthesia, occlusal discrepancies, soft tissue infection, immediate and late inflammatory reactions related to biodegradation process, and any need for the removal of the plates. Statistical Analysis Used: Descriptives, Frequencies, and Chi-square test were used. Results: In our study, the age group range was 5 to 55 years. Road traffic accidents accounted for the majority of patients six, (46.2%). Postoperative occlusal discrepancies were found in seven patients as mild to moderate, which resolved with IMF for 1-8 weeks. There were minimal complications seen and only as soft tissue infection. Conclusions: Use of biodegradable osteosynthesis system is a reliable alternative method for the fixation of zygomatic-complex and mandibular fractures. The biodegradable system still needs to be refined in material quality and handling to match the stability achieved with metal system. Biodegradable plates and screws is an ideal system for pediatric fractures with favorable outcome. PMID:23662255

  8. Repair of defects and osteosynthesis of long bones in children with osteoclastoma

    NASA Astrophysics Data System (ADS)

    Ryzhikov, D. V.; Gubina, E. V.; Podorozhnaya, V. T.; Senchenko, E. V.; Sadovoy, M. A.

    2016-08-01

    The paper is aimed at reporting a retrospective analysis covering the period from 2007 to 2015. The study involved 22 patients with benign osteoclastoma (OC), 14 male and 8 female children aged 9 to 19. All patients had monostotic lesions with the following location of pathological foci: humerus—11 patients, femoral bone—7, shin bone— 1, fibular bone—1, and ulnar bone—1. All 22 patients underwent surgery. Surgical treatment included resection of tumor focus within intact tissues (in cases of eccentric foci, bony bridge was preserved in the area of minimum damage, which was treated by electrocoagulation together with the cavity) together with bone grafting and intramedullary reinforcement of the affected bone (which provides stable osteosynthesis, early mobilization, and prevention of functional deficits in most patients). Consolidation was achieved in 100% of the operated patients.

  9. [Blood circulation features by treatment of multiply mandible fractures by means of transosseus osteosynthesis].

    PubMed

    Krasnov, V V; Kononovich, N A

    2013-01-01

    The multiple injury of the mandible was modeled experimentally in 27 adult mongrel dogs with subsequent fixation using a device for transosseous osteosynthesis. The special features of soft tissue hemodynamics in the injury zone and contralateral symmetrical part were studied. It has been determined that the unidirectional changes in functional properties of the arterial bed vessels occur under the conditions created, and these changes are more marked on the injury side and characterized by vasodilatation. Circulation in the injury zone doesn't recover by the end of fixation. Performing the measures directed for the improvement of vascular elastotonic properties during mandibular fracture treatment will allow to decrease the degree of hemodynamics disorders in paraosseous tissues, as well as will have a positive effect on a final clinical outcome.

  10. [Treatment outcome for forearm shaft fracture using AO plate stabilization].

    PubMed

    Kaleta, M; Małecki, P; Tokarowski, A; Kusz, D

    1995-01-01

    Results of treatment for 104 forearm shaft fractures in 70 patients have been presented. In all cases included in this study an open reduction of the fracture was followed by AO plate stabilization. Functional and radiological assessment was carried out according to the criteria of Anderson et al. Excellent and good functional results were achieved in 48 cases, fair in 10 and poor in 12 cases. The ulna united in 75%, the radius in 78% (delayed union included). Cross- union occurred in three patients, one case of destabilization at fracture site was observed, no infection has been noted. AO plate osteosynthesis proved to be still valuable mode of treatment for forearm shaft fracture. PMID:7587501

  11. Moving Divertor Plates in a Tokamak

    SciTech Connect

    S.J. Zweben, H. Zhang

    2009-02-12

    Moving divertor plates could help solve some of the problems of the tokamak divertor through mechanical ingenuity rather than plasma physics. These plates would be passively heated on each pass through the tokamak and cooled and reprocessed outside the tokamak. There are many design options using varying plate shapes, orientations, motions, coatings, and compositions.

  12. [Humerus varus: correction by proximal valgus osteotomy with precontourned plate fixation in children].

    PubMed

    Tallón-López, J; Domínguez-Amador, J J; Andrés-García, J A

    2014-01-01

    Varus deformity of the proximal humerus in children is a little known pathology due to its low incidence of presentation. Progress has been made in recent years in understanding the possible etiology and pathophysiological causes. Radiological criteria for diagnosis and functional impairment that occurs have also been defined. However, there are few reports in the literature about the surgical treatment of this deformity in children. In this paper we present a case of surgical treatment of this deformity by corrective osteotomy fixed with precontoured external maleolar plate osteosynthesis.

  13. Bone Repair on Fractures Treated with Osteosynthesis, ir Laser, Bone Graft and Guided Bone Regeneration: Histomorfometric Study

    NASA Astrophysics Data System (ADS)

    dos Santos Aciole, Jouber Mateus; dos Santos Aciole, Gilberth Tadeu; Soares, Luiz Guilherme Pinheiro; Barbosa, Artur Felipe Santos; Santos, Jean Nunes; Pinheiro, Antonio Luiz Barbosa

    2011-08-01

    The aim of this study was to evaluate, through the analysis of histomorfometric, the repair of complete tibial fracture in rabbits fixed with osteosynthesis, treated or not with infrared laser light (λ780 nm, 50 mW, CW) associated or not to the use of hydroxyapatite and guided bone regeneration (GBR). Surgical fractures were created, under general anesthesia (Ketamina 0,4 ml/Kg IP and Xilazina 0,2 ml/Kg IP), on the dorsum of 15 Oryctolagus rabbits that were divided into 5 groups and maintained on individual cages, at day/night cycle, fed with solid laboratory pelted diet and had water ad libidum. On groups II, III, IV and V the fracture was fixed with wire osteosynthesis. Animals of groups III and V were grafted with hydroxyapatite and GBR technique used. Animals of groups IV and V were irradiated at every other day during two weeks (16 J/cm2, 4×4 J/cm2). Observation time was that of 30 days. After animal death (overdose of general anesthetics) the specimes were routinely processed to wax and underwent histological analysis by light microscopy. The histomorfometric analysis showed an increased bone neoformation, increased collagen deposition, less reabsorption and inflammation when laser was associated to the HATCP. It is concluded that IR laser light was able to accelerate fracture healing and the association with HATCP and GBR resulted on increased deposition of CHA.

  14. Management of pediatric mandibular fractures using bioresorbable plating system – Efficacy, stability, and clinical outcomes: Our experiences and literature review

    PubMed Central

    Singh, Mahinder; Singh, R.K.; Passi, Deepak; Aggarwal, Mohit; Kaur, Guneet

    2015-01-01

    Aims The purpose of this study was to determine the efficacy and stability of the biodegradable fixation system for treatment of mandible fractures in pediatric patients by measuring the bite force. Methods Sixty pediatric patients with mandibular fractures (36 males, 24 females) were included in this study. The 2.5-mm resorbable plates were adapted along Champy's line of ideal osteosynthesis and secured with four 2.5 mm diameter monocortical resorbable screws, 8 mm in length. All patients were followed for 10 months. Clinical parameters, such as soft tissue infection, nonunion, malunion, implant exposure, malocclusion, nerve injury, and bite force for stability, were prospectively assessed. Results Adequate fixation and primary bone healing was achieved in 100% of the cases. Six minor complications (10%) were observed: 2 soft tissue infections (3%), 1 plate dehiscence (2%), 1 malocclusion (2%), and 2 paresthesia (3%). Conclusion 2.5-mm resorbable plating system along Champy's line of ideal osteosynthesis is a good treatment modality for mandible fractures in pediatric patients. PMID:27195206

  15. Plating of proximal fracture of the humerus: a study of 30 cases.

    PubMed

    Iacobellis, C; Fountzoulas, K; Aldegheri, R

    2011-07-01

    In recent years, plate osteosynthesis with angular stable implants is frequently used for severely displaced three- and four-part proximal humeral fractures. The aim of this study is to evaluate early results of these fractures treated with insertion of LCP or Philos plates. We present results in 30 cases of proximal humeral fractures, 17 with 3 parts according to Neer and 13 with 4 parts, treated with Locking Compression Plates (LCP, 14 cases) and Philos plates (16) by the deltopectoral approach. Patients were checked with standard X-rays and clinical evaluation, according to the Constant-Murley shoulder score, Individual Constant score and Relative Constant score. Mean follow-up time was 21 months (range 6-42 months). The mean Constant-Murley shoulder scores were Pain 10.6 (3-15), Activities of Daily Living 15.3 (2-20), Range of Motion 26.8 (12-40) and Power 10.3 (3-25) and Total 63 (25-97). The Individual Constant score was 68.6% (27-98%) and the Relative Constant score 85.4% (36-130%). Fractures in 3 parts (of the surgical or anatomic humeral neck and major tubercle) had a mean Constant score of 69.1 (17 cases), but this fell to 55 (13 cases) in those in 4 parts (neck, major and lesser tubercles). Late necrosis of the humeral head occurred in two cases, both with 4-part breaks. We thus believe that 3-part fractures, in which both reduction and stable osteosynthesis are easier, show favourable prognosis and should be clearly distinguished from 4-part ones during assessments. The deltopectoral approach offers good exposure and is especially recommended in 4-part fractures, also because it provides a good view of the lesser tubercle. The osteosynthesis must be stable if early mobilisation of the shoulder and proper recovery of range of motion are to be achieved. As well as reduction and stabilisation of the tubercles, it is also important to restore the neck/shaft angle and stabilise it with oblique screws fitting the plate to avoid varus malposition.

  16. Quaternions as astrometric plate constants

    NASA Technical Reports Server (NTRS)

    Jefferys, William H.

    1987-01-01

    A new method for solving problems in relative astrometry is proposed. In it, the relationship between the measured quantities and the components of the position vector of a star is modeled using quaternions, in effect replacing the plate constants of a standard four-plate-constant solution with the four components of a quaternion. The method allows a direct solution for the position vectors of the stars, and hence for the equatorial coordinates. Distortions, magnitude, and color effects are readily incorporated into the formalism, and the method is directly applicable to overlapping-plate problems. The advantages of the method include the simplicity of the resulting equations, their freedom from singularities, and the fact that trigonometric functions and tangential point transformations are not needed to model the plate material. A global solution over the entire sky is possible.

  17. Biodegradable calcium polyphosphate/polyvinyl-urethane carbonate composites for osteosynthesis applications

    NASA Astrophysics Data System (ADS)

    Ramsay, Scott Desmond

    The formation of biodegradable implants for use in osteosynthesis has been a major goal of biomaterials research for the past two to three decades. Self-reinforced polylactide systems represent the most significant success of this research to date, however with elastic constants of, at most, 12--15 GPa, they fail to provide the necessary initial stiffness required of devices designed for stabilizing fractures of major load-bearing bones. One objective of this study has been the development of a biodegradable composite suitable for fabrication of implants for the repair of fractures of major load-bearing bones. Specifically, this research has focussed on the use of calcium polyphosphate (CPP), an uiorganic polymer in combination with polyvinyl-urethane carbonate (PVUC) organic polymers. Composite samples were formed as interpenetrating phase composites (IPC), particle-reinforced composites (PRC), and fibre-reinforced composites (FRC). Additionally, the IPCs were produced as both monolithic and laminated specimens. PRC samples exhibit too low asmade elastic constant for fracture fixation applications, while the IPC and FRC samples exhibit desired as-made strength and bending stiffness but lose these properties too rapidly when exposed to aqueous-based in vitro aging, simulating in vivo conditions. An investigation to determine the mechanism of the rapid in vitro degradation was undertaken using a model IPC system to study the effect of the interfacial strength on the mechanical properties of the composite. In addition, these studies provided further support for a hypothesis to explain the observed high mechanical properties of the as-made CPP-PVUC interpenetrating phase composites. It was found that strong interfacial strength is very significant in obtaining appropriate mechanical properties in the IPC system. Results support the conclusion that a rapid loss of the CPP-PVUC interface through exposure to an aqueous environment, as well as stresses imposed on the CPP

  18. Dynamic locking plates provide symmetric axial dynamization to stimulate fracture healing.

    PubMed

    Tsai, Stanley; Fitzpatrick, Daniel C; Madey, Steven M; Bottlang, Michael

    2015-08-01

    Axial dynamization of an osteosynthesis construct can promote fracture healing. This biomechanical study evaluated a novel dynamic locking plate that derives symmetric axial dynamization by elastic suspension of locking holes within the plate. Standard locked and dynamic plating constructs were tested in a diaphyseal bridge-plating model of the femoral diaphysis to determine the amount and symmetry of interfragmentary motion under axial loading, and to assess construct stiffness under axial loading, torsion, and bending. Subsequently, constructs were loaded until failure to determine construct strength and failure modes. Finally, strength tests were repeated in osteoporotic bone surrogates. One body-weight axial loading of standard locked constructs produced asymmetric interfragmentary motion that was over three times smaller at the near cortex (0.1 ± 0.01 mm) than at the far cortex (0.32 ± 0.02 mm). Compared to standard locked constructs, dynamic plating constructs enhanced motion by 0.32 mm at the near cortex and by 0.33 mm at the far cortex and yielded a 77% lower axial stiffness (p < 0.001). Dynamic plating constructs were at least as strong as standard locked constructs under all test conditions. In conclusion, dynamic locking plates symmetrically enhance interfragmentary motion, deliver controlled axial dynamization, and are at least comparable in strength to standard locked constructs. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1218-1225, 2015.

  19. Clinical application of locked plating system in children. An orthopaedic view

    PubMed Central

    Zafra-Jimenez, Jose Alberto; Rodriguez Martin, Juan

    2010-01-01

    In recent years, the locked plating system has gained favour in the treatment of certain fractures in adults; however, there is not much information regarding its use in children. We think there could be some advantages and applications such as: an alternative to external fixation, the bridge plating technique, unicortical screws, removal of hardware, metadiaphyseal fractures, periarticular fractures, poor quality bone, and allograft fixation. However, there are some disadvantages to keep in mind and the final decision for using it should be based on the osteosynthesis method principle the surgeon would like to apply. In this review article we discuss the up-to-date possible clinical applications and issues of this system. PMID:20162415

  20. Vibration of plates using plate characteristic functions obtained by reduction of partial differential equation

    NASA Astrophysics Data System (ADS)

    Bhat, R. B.; Mundkur, G.

    1993-02-01

    Vibration of rectangular plates is studied using a set of plate characteristic functions generated by reduction of the plate partial differential equation, and exactly solving the resulting ordinary differential equation. The plate characteristic functions are used as deflection shape functions in the Rayleigh-Ritz method to obtain the natural frequencies. Because the solution is exact in one direction, the results fall in between the exact values and those obtained with the straight forward Rayleigh-Ritz method, where the complete deflection shape is assumed initially. Results are provided for rectangular plates with combinations of clamped, simply supported and free edge conditions.

  1. Thermal stresses and deflections of cross-ply laminated plates using refined plate theories

    NASA Technical Reports Server (NTRS)

    Khdeir, A. A.; Reddy, J. N.

    1991-01-01

    Exact analytical solutions of refined plate theories are developed to study the thermal stresses and deflections of cross-ply rectangular plates. The state-space approach in conjunction with the Levy method is used to solve exactly the governing equations of the theories under various boundary conditions. Numerical results of the higher-order theory of Reddy for thermal stresses and deflections are compared with those obtained using the classical and first-order plate theories.

  2. Impact on multilayered composite plates

    NASA Technical Reports Server (NTRS)

    Kim, B. S.; Moon, F. C.

    1977-01-01

    Stress wave propagation in a multilayer composite plate due to impact was examined by means of the anisotropic elasticity theory. The plate was modelled as a number of identical anisotropic layers and the approximate plate theory of Mindlin was then applied to each layer to obtain a set of difference-differential equations of motion. Dispersion relations for harmonic waves and correction factors were found. The governing equations were reduced to difference equations via integral transforms. With given impact boundary conditions these equations were solved for an arbitrary number of layers in the plate and the transient propagation of waves was calculated by means of a Fast Fourier Transform algorithm. The multilayered plate problem was extended to examine the effect of damping layers present between two elastic layers. A reduction of the interlaminar normal stress was significant when the thickness of damping layer was increased but the effect was mostly due to the softness of the damping layer. Finally, the problem of a composite plate with a crack on the interlaminar boundary was formulated.

  3. Analysis of hydraulic instability of ANS involute fuel plates

    SciTech Connect

    Sartory, W.K.

    1991-11-01

    Curved shell equations for the involute Advanced Neutron Source (ANS) fuel plates are coupled to two-dimensional hydraulic channel flow equations that include fluid friction. A complete set of fluid and plate boundary conditions is applied at the entrance and exit and along the sides of the plate and the channel. The coupled system is linearized and solved to assess the hydraulic instability of the plates.

  4. A Refined Shear Deformation Plate Theory

    NASA Astrophysics Data System (ADS)

    Liu, Yucheng

    2011-04-01

    An improved higher-order shear deformation theory of plates is presented in this paper. The theory is developed from the transverse shear deformation theory presented by Ambartsumian [11]. The present plate theory contains kinematics of higher-order displacement field of plates, a system of higher-order differential equilibrium equations in terms of the three generalized displacements of bending plates, and a system of boundary conditions at each edge of plate boundaries. The present shear deformation theory of plates is validated by applying it to solve torsional plates and simply supported plates. The obtained solutions using the present theory are compared with the solutions of other shear-deformation theories. A good agreement is achieved through these comparisons and the advantages of the present theory are clearly verified. The shear deformation plate theory presented here can be applied to the analysis of laminated composite plates to better predict their dynamic and static behaviors. The proposed theory should also be supplemented to the theory of finite element analysis for developing new shell elements.

  5. Extrinsic subclavian vein compression after osteosynthesis of a midshaft clavicular fracture in an athlete.

    PubMed

    Rossi, Luciano A; Piuzzi, Nicolas S; Bongiovanni, Santiago L; Tanoira, Ignacio; Maignon, Gaston; Ranalletta, Maximiliano

    2015-01-01

    Clavicle fractures are common injuries. Traditionally, nonsurgical management has been favored; however, recent evidence has emerged indicating that operative fixation produces lower nonunion rates, better functional outcomes, improved cosmesis, and greater patient satisfaction. Although clavicle fixation has been considered a safe procedure, several complications related to plate fixation have been reported. We report a case of a 21-year-old basketball player that had a vascular complication associated with internal fixation of a clavicle fracture. An external compression of the subclavian vein was attributed to a long screw of a precontoured clavicular plate. Although vascular complications associated with clavicle fixation are rare, they may be limb and even life threating. It is advisable that surgeons take measures to avoid them especially when placing the medial screws.

  6. Osteosynthesis of ununited femoral neck fracture by internal fixation combined with iliac crest bone chips and muscle pedicle bone grafting

    PubMed Central

    Baksi, D D; Pal, A K; Baksi, D P

    2016-01-01

    Background: Ununited femoral neck fracture is seen commonly in developing countries due to delayed presentation or failure of primary internal fixation. Such fractures, commonly present with partial or total absorption of femoral neck, osteonecrosis of femoral head in 8–30% cases with upward migration of trochanter posing problem for osteosynthesis, especially in younger individuals. Several techniques for treatment of such conditions are described like osteotomies or nonvascularied cortical or cancellous bone grafting provided varying degrees of success in terms of fracture union but unsatisfactory long term results occurred due to varying incidence of avascular necrosis (AVN) of femoral head. Moreover, in presence of AVN of femoral head neither free fibular graft nor cancellous bone graft is satisfactory. The vascularied bone grafting by deep circumflex iliac artery based on iliac crest bone grafting, free vascularied fibular grafting and muscle pedicle periosteal grafting showed high incidence of success rate. Osteosynthesis is the preferred treatment of choice in ununited femoral neck fracture in younger individuals. Materials and Methods: Of the 293 patients operated during the period from June 1977 to June 2009, 42 were lost to followup. Seven patients with gluteus medius muscle pedicle bone grafting (MPBG) were excluded. Thus, out of 244 patients, 208 (85.3%) untreated nonunion and 36 (14.7%) following failure of primary internal fixation were available for studies. Time interval between the date of injury and operation in untreated nonunion cases was mean 6.5 months and in failed internal fixation cases was mean 11.2 months. Ages of the patients varied from 16 to 55 years. Seventy patients had partial and 174 had subtotal absorption of the femoral neck. Evidence of avascular necrosis (AVN) femoral head was found histologically in 135 (54.3%) and radiologically in 48 (19.7%) patients. The patients were operated by open reduction of fracture, cannulated hip

  7. Corrugated cover plate for flat plate collector

    DOEpatents

    Hollands, K. G. Terry; Sibbitt, Bruce

    1978-01-01

    A flat plate radiant energy collector is providing having a transparent cover. The cover has a V-corrugated shape which reduces the amount of energy reflected by the cover away from the flat plate absorber of the collector.

  8. Osteotomy and osteosynthesis in complex segmental genioplasty with double surgical guide

    PubMed Central

    Assis, Adriano; Olate, Sergio; Asprino, Luciana; de Moraes, Márcio

    2014-01-01

    Chin osteotomy is used in esthetic and functional procedure; genioplasty shows different surgical options as lineal osteotomy, curved osteotomy, segmental osteotomy and others for different conditions of the face. This communication shows the use of two surgical guides used in a patient with extremely facial asymmetry; the surgical plan was realized in a stereolithographic biomodel. The first surgical guide was used for osteotomy and the second surgical guide was used for putting the plate, previously bent, and for segmented osteotomy in the planned position on the biomodel; this technique showed adequate adaptation and security in this extremely asymmetric case. The potential use of this surgical guide was discussed. PMID:24995074

  9. Absolute Plate Velocities from Seismic Anisotropy

    NASA Astrophysics Data System (ADS)

    Kreemer, Corné; Zheng, Lin; Gordon, Richard

    2015-04-01

    The orientation of seismic anisotropy inferred beneath plate interiors may provide a means to estimate the motions of the plate relative to the sub-asthenospheric mantle. Here we analyze two global sets of shear-wave splitting data, that of Kreemer [2009] and an updated and expanded data set, to estimate plate motions and to better understand the dispersion of the data, correlations in the errors, and their relation to plate speed. We also explore the effect of using geologically current plate velocities (i.e., the MORVEL set of angular velocities [DeMets et al. 2010]) compared with geodetically current plate velocities (i.e., the GSRM v1.2 angular velocities [Kreemer et al. 2014]). We demonstrate that the errors in plate motion azimuths inferred from shear-wave splitting beneath any one tectonic plate are correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two-tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining relative plate angular velocities to consistency with the MORVEL relative plate angular velocities. The SKS-MORVEL absolute plate angular velocities (based on the Kreemer [2009] data set) are determined from the poles from eight plates weighted proportionally to the root-mean-square velocity of each plate. SKS-MORVEL indicates that eight plates (Amur, Antarctica, Caribbean, Eurasia, Lwandle, Somalia, Sundaland, and Yangtze) have angular velocities that differ insignificantly from zero. The net rotation of the lithosphere is 0.25±0.11° Ma-1 (95% confidence limits) right-handed about 57.1°S, 68.6°E. The within-plate dispersion of seismic anisotropy for oceanic lithosphere (σ=19.2° ) differs insignificantly from that for continental lithosphere (σ=21.6° ). The between-plate dispersion, however, is significantly smaller for oceanic lithosphere (σ=7.4° ) than for continental

  10. Group Problem Solving.

    ERIC Educational Resources Information Center

    King, James C.

    1988-01-01

    This pamphlet discusses group problem solving in schools. Its point of departure is that teachers go at problems from a number of different directions and that principals need to capitalize on those differences and bring a whole range of skills and perceptions to the problem-solving process. Rather than trying to get everyone to think alike,…

  11. Teaching through Problem Solving

    ERIC Educational Resources Information Center

    Fi, Cos D.; Degner, Katherine M.

    2012-01-01

    Teaching through Problem Solving (TtPS) is an effective way to teach mathematics "for" understanding. It also provides students with a way to learn mathematics "with" understanding. In this article, the authors present a definition of what it means to teach through problem solving. They also describe a professional development vignette that…

  12. Chemical Reaction Problem Solving.

    ERIC Educational Resources Information Center

    Veal, William

    1999-01-01

    Discusses the role of chemical-equation problem solving in helping students predict reaction products. Methods for helping students learn this process must be taught to students and future teachers by using pedagogical skills within the content of chemistry. Emphasizes that solving chemical reactions should involve creative cognition where…

  13. Techniques of Problem Solving.

    ERIC Educational Resources Information Center

    Krantz, Steven G.

    The purpose of this book is to teach the basic principles of problem solving in both mathematical and non-mathematical problems. The major components of the book consist of learning to translate verbal discussion into analytical data, learning problem solving methods for attacking collections of analytical questions or data, and building a…

  14. Preliminary results from osteosynthesis using Ender nails by means of a percutaneous technique, in humeral diaphysis fractures in adults☆

    PubMed Central

    Godinho, Glaydson Gomes; França, Flávio de Oliveira; Freitas, José Márcio Alves; Santos, Flávio Márcio Lago; Correa, Guilherme de Almeida Sellos; Maia, Lucas Russo

    2015-01-01

    Objective To demonstrate the clinical and functional results from treatment of humeral diaphysis fractures using Ender nails. Methods Eighteen patients who underwent osteosynthesis of humeral diaphysis fractures using Ender nails were evaluated. In addition to the clinical and radiographic evaluations, patients with a minimum of one year of follow-up were assessed by means of the Constant, American Shoulder and Elbow Surgeons (ASES), Mayo Clinic and Simple Shoulder Value (SSV) functional scores, and in relation to the degree of satisfaction with the final result. The fixation technique used was by means of an anterograde percutaneous route. Results All the patients achieved fracture consolidation, after a mean of 2.9 months (ranging from 2 to 4 months). The mean Constant score was 85.7 (ranging from 54 to 100) and the mean ASES score was 95.9 (ranging from 76 to 100). All the patients achieved the maximum score on the Mayo Clinic scale. Conclusion Fixation of humeral diaphysis fractures using Ender nails by means of a percutaneous technique was shown to be a method with promising preliminary results. PMID:26417566

  15. Fabrication of a biodegradable calcium polyphosphate/polyvinyl-urethane carbonate composite for high load bearing osteosynthesis applications.

    PubMed

    Ramsay, Scott D; Pilliar, Robert M; Santerre, J Paul

    2010-07-01

    The formation of biodegradable implants for use in osteosynthesis has been a major goal of biomaterials research for the past 2-3 decades. Self-reinforced polylactide systems represent the most significant success of this research to date, however, with elastic constants up to 12-15 GPa at best, they fail to provide the initial stiffness required of devices for stabilizing fractures of major load-bearing bones. Our research has investigated the use of calcium polyphosphate (CPP), an inorganic polymer in combination with polyvinyl-urethane carbonate (PVUC) organic polymers for such applications. Initial studies indicated that composite samples formed as interpenetrating phase composites (IPC) exhibited suitable as-made strength and stiffness, however, they displayed a rapid loss of properties when exposed to in vitro aging. An investigation to determine the mechanism of this accelerated in vitro degradation for the IPCs as well as to identify possible design changes to overcome this drawback was undertaken using a model IPC system. It was found that strong interfacial strength and minimal swelling of the PVUC are very important for obtaining and maintaining appropriate mechanical properties in vitro.

  16. Biodegradable Fe-based alloys for use in osteosynthesis: outcome of an in vivo study after 52 weeks.

    PubMed

    Kraus, Tanja; Moszner, Frank; Fischerauer, Stefan; Fiedler, Michael; Martinelli, Elisabeth; Eichler, Johannes; Witte, Frank; Willbold, Elmar; Schinhammer, Michael; Meischel, Martin; Uggowitzer, Peter J; Löffler, Jörg F; Weinberg, Annelie

    2014-07-01

    This study investigates the degradation performance of three Fe-based materials in a growing rat skeleton over a period of 1 year. Pins of pure Fe and two Fe-based alloys (Fe-10 Mn-1Pd and Fe-21 Mn-0.7C-1Pd, in wt.%) were implanted transcortically into the femur of 38 Sprague-Dawley rats and inspected after 4, 12, 24 and 52 weeks. The assessment was performed by ex vivo microfocus computed tomography, weight-loss determination, surface analysis of the explanted pins and histological examination. The materials investigated showed signs of degradation; however, the degradation proceeded rather slowly and no significant differences between the materials were detected. We discuss these unexpected findings on the basis of fundamental considerations regarding iron corrosion. Dense layers of degradation products were formed on the implants' surfaces, and act as barriers against oxygen transport. For the degradation of iron, however, the presence of oxygen is an indispensable prerequisite. Its availability is generally a critical factor in bony tissue and rather limited there, i.e. in the vicinity of our implants. Because of the relatively slow degradation of both pure Fe and the Fe-based alloys, their suitability for bulk temporary implants such as those in osteosynthesis applications appears questionable.

  17. Fabrication of a biodegradable calcium polyphosphate/polyvinyl-urethane carbonate composite for high load bearing osteosynthesis applications.

    PubMed

    Ramsay, Scott D; Pilliar, Robert M; Santerre, J Paul

    2010-07-01

    The formation of biodegradable implants for use in osteosynthesis has been a major goal of biomaterials research for the past 2-3 decades. Self-reinforced polylactide systems represent the most significant success of this research to date, however, with elastic constants up to 12-15 GPa at best, they fail to provide the initial stiffness required of devices for stabilizing fractures of major load-bearing bones. Our research has investigated the use of calcium polyphosphate (CPP), an inorganic polymer in combination with polyvinyl-urethane carbonate (PVUC) organic polymers for such applications. Initial studies indicated that composite samples formed as interpenetrating phase composites (IPC) exhibited suitable as-made strength and stiffness, however, they displayed a rapid loss of properties when exposed to in vitro aging. An investigation to determine the mechanism of this accelerated in vitro degradation for the IPCs as well as to identify possible design changes to overcome this drawback was undertaken using a model IPC system. It was found that strong interfacial strength and minimal swelling of the PVUC are very important for obtaining and maintaining appropriate mechanical properties in vitro. PMID:20524193

  18. Large Deflections of Elastic Rectangular Plates

    NASA Astrophysics Data System (ADS)

    Razdolsky, A. G.

    2015-11-01

    It is known that elastic large deflections of thin plates are governed by von Karman nonlinear equations. The analytical solution of these equations in the general case is unfeasible. Samuel Levy, in 1942, showed that large deflections of the rectangular plate can be expressed as a double series of sine-shaped harmonics (deflection harmonics). However, this method gave no way of creating the computer algorithm of solving the problem. The stress function expression taken in the Levy's method must be revised to find the approach that takes into account of all possible products of deflection coefficients. The algorithm of solving the problem for the rectangular plate with an arbitrary aspect ratio under the action of the lateral distributed load is reported in this paper. The approximation of the plate deflection is taken in the form of double series proposed by Samuel Levy. However, the expression for the stress function is presented in the form that incorporates products of deflection coefficients in the explicit form in distinction to the Levy's expression. The number of harmonics in the deflection expression may be arbitrary. The algorithm provides composing the system of governing cubic equations, which includes the deflection coefficients in the explicit form. Solving the equation system is based on using the principle of minimum potential energy. A method of the gradient descent is applied to find the equilibrium state of the plate as the minimum point of the potential energy. A computer program is developed on the basis of the present algorithm. Numerical examples carried out for the plate model with 16 deflection harmonics illustrate the potentialities of the program. The results of solving the examples are presented in the graphical form for the plates with a different aspect ratio and may be used under designing thin-walled elements of airplane and ship structures.

  19. Poisson-Boltzmann theory for two parallel uniformly charged plates

    NASA Astrophysics Data System (ADS)

    Xing, Xiangjun

    2011-04-01

    We solve the nonlinear Poisson-Boltzmann equation for two parallel and like-charged plates both inside a symmetric electrolyte, and inside a 2:1 asymmetric electrolyte, in terms of Weierstrass elliptic functions. From these solutions we derive the functional relation between the surface charge density, the plate separation, and the pressure between plates. For the one plate problem, we obtain exact expressions for the electrostatic potential and for the renormalized surface charge density, both in symmetric and in asymmetric electrolytes. For the two plate problems, we obtain new exact asymptotic results in various regimes.

  20. The primary resonance of laminated piezoelectric rectangular plates.

    PubMed

    Zhao, Shuai; Shi, Zhifei; Xiang, Hongjun

    2009-11-01

    Based on Hamilton's principle and the Rayleigh-Ritz method, a model of a nonlinear dynamic laminated piezoelectric rectangular plate was established, and the governing equations were derived and solved for both the thin-plate and thick-plate models. In the present investigation, the nonlinear constitutive relations of piezoelectric materials were considered and the effects of the nonlinearity on the response of the plate were discovered. The primary resonance of rectangular plate is investigated with the use of the method of multiple scales. The results obtained in the present paper agree very well with the experiment results.

  1. Sputtering and ion plating

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The proceedings of a conference on sputtering and ion plating are presented. Subjects discussed are: (1) concepts and applications of ion plating, (2) sputtering for deposition of solid film lubricants, (3) commercial ion plating equipment, (4) industrial potential for ion plating and sputtering, and (5) fundamentals of RF and DC sputtering.

  2. Distal humerus fractures in the elderly: osteosynthesis or endoprosthesis? Review of the literature.

    PubMed

    Dietz, S O; Burkhart, K E; Nowak, T E; Rommens, P M; Müller, L P

    2012-12-01

    Fractures of the distal humerus in adults are rare but challenging for the orthopaedic trauma surgeon. The bimodal distribution reflects the trauma mechanism. While distal humerus fractures are caused by high-energy traumata in young male adults, a fall from a standing height is the most common reason for humerus fractures among elderly females. As a rule, fractures of the distal humerus are treated surgically. In young patients, open reduction and internal fixation (ORIF) with anatomic locking plates are the gold standard. In elderly patients, reconstruction is not always possible, and total elbow arthroplasty (TEA) becomes necessary. The present article provides an overview of the current diagnostic and treatment recommendations. The current literature is reviewed and the results discussed. PMID:26814545

  3. Biomechanical evaluation of maxillary Lefort Ι fracture with bioabsorbable osteosynthesis internal fixation.

    PubMed

    Wu, Wei; Zhou, Jiang; Xu, Chong-Tao; Zhang, Jie; Jin, Yan-Jiao; Sun, Geng-Lin

    2014-12-01

    The aim of this study was to apply biomechanical analysis model to evaluate the effects of bioabsorbable internal fixation devices on maxillary Lefort Ι fracture. CT scan technology and the finite element software (ansys) were used to establish three-dimensional finite element models of five resorbable internal fixation devices in maxillary Lefort Ι fractures. We used the model to calculate the stress of the upper jaw and internal fixation. We further analyzed the stability of fixation under four occlusions. The fixation using two bioabsorbable plates was not stable. The zygomaticomaxillary pillars fixation is more stable than other fixations. The stability of fracture fixation was influenced with the molar occlusion. The current study developed a functional three-dimensional finite element model of bioabsorbable internal fixation and compared the stability of five fixation methods for maxillary Lefort Ι fractures. The results would facilitate the application of bioabsorbable materials in dental clinic.

  4. NAEP Note: Problem Solving.

    ERIC Educational Resources Information Center

    Carpenter, Thomas P.; And Others

    1980-01-01

    Student weaknesses on problem-solving portions of the NAEP mathematics assessment are discussed using Polya's heuristics as a framework. Recommendations for classroom instruction are discussed. (MP) Aspect of National Assessment (NAEP) dealt with in this document: Results (Interpretation).

  5. Problem Solving and Learning

    NASA Astrophysics Data System (ADS)

    Singh, Chandralekha

    2009-07-01

    One finding of cognitive research is that people do not automatically acquire usable knowledge by spending lots of time on task. Because students' knowledge hierarchy is more fragmented, "knowledge chunks" are smaller than those of experts. The limited capacity of short term memory makes the cognitive load high during problem solving tasks, leaving few cognitive resources available for meta-cognition. The abstract nature of the laws of physics and the chain of reasoning required to draw meaningful inferences makes these issues critical. In order to help students, it is crucial to consider the difficulty of a problem from the perspective of students. We are developing and evaluating interactive problem-solving tutorials to help students in the introductory physics courses learn effective problem-solving strategies while solidifying physics concepts. The self-paced tutorials can provide guidance and support for a variety of problem solving techniques, and opportunity for knowledge and skill acquisition.

  6. [Treatment of supramalleolar open fractures by means of centro-medullary osteosynthesis of the fibula].

    PubMed

    Radu, C; Barbu, D; Maksay, S

    1978-01-01

    The study is concerned with 11 cases of open supra-malleolar fractures involving both bones. The tibial fracture was of the comminutive type, with a large number of small fragments allowing an exteriorization of the proximal end or telescoping of the ends with consecutive loss of the axis. Due to a difficult synthesis of the tibial bone synthesis of the peroneum with a thick rod or with a brooch was performed, recovering the length of the lever and allowing to de-telescope the tibial focus, to recover the normal length and a corresponding axis. Since in all the treated cases consolidation was achieved over a duration of 5 months, the advantage is stressed, of the procedure which, solving indirectly the fracture, protects the tibial focus, already poorly irrigated and susceptible to pseudarthrosis in thi;s type of location. PMID:580461

  7. Analysis of skew plate problems with various constraints

    NASA Astrophysics Data System (ADS)

    Mizusawa, T.; Kajita, T.; Naruoka, M.

    1980-12-01

    This paper presents the application of the modified Rayleigh-Ritz method with Lagrange multipliers to analyze skew plate problems with various constraints. By this procedure one can satisfy both geometric and natural boundary conditions of skew plates. To demonstrate the accuracy and versatility of the method, several examples of bending, vibration and buckling of skew plates are solved, and results are compared with those obtained by other approximate methods.

  8. Turbulent flows near flat plates

    NASA Astrophysics Data System (ADS)

    Kambe, R.; Imamura, T.; Doi, M.

    1980-08-01

    The method to study the effect of the plate moving in the homogeneous or isotropic turbulence is presented. The crucial point of this method is to solve the Orr-Sommerfeld like equation, which is satisfied by the kernel of the Wiener-Hermite expansion of the velocity field, under the inhomogeneous boundary condition. In the special case of constant mean flow, our method gives the same result as that of Hunt and Graham and succeeds in explaining the experimental results of Thomas and Hancock. The method is also applied to the case of nonuniform mean flow, where the shear effect comes up.

  9. COMPARATIVE STUDY BETWEEN OSTEOSYNTHESIS IN CONVENTIONAL AND BIOABSORBABLE IMPLANTS IN ANKLE FRACTURES

    PubMed Central

    Gaiarsa, Guilherme Pelosini; dos Reis, Paulo Roberto; Mattar, Rames; Silva, Jorge dos Santos; Fernandez, Túlio Diniz

    2015-01-01

    ABSTRACT Objective: To compare the functional results of ankle fractures treated with metallic and absorbable plates. Twenty patients were randomized into two groups (metallic and absorbable implant groups) and followed prospectively. In the immediate postoperative period, patients were immobilized with plaster casts for one week, which was replaced by a removable cast for another four weeks. Partial weight-bearing was allowed after three weeks, and full weight-bearing after six weeks. Functional recovery was similar in both groups. At six months, three patients in the metallic group complained of local pain, and had their implants removed. One patient in the absorbable group exhibited early dehiscence of the suture and underwent debridement and suturing with good evolution. The American Orthopaedic Foot and Ankle Society (AOFAS) score was similar between the two groups after six and nine months of follow-up. The absorbable implants showed clinical and functional results that were similar to those of metallic implants. Level of Evidence II, Prospective Comparative Study. PMID:26981035

  10. Dynamic locking plates provide symmetric axial dynamization to stimulate fracture healing.

    PubMed

    Tsai, Stanley; Fitzpatrick, Daniel C; Madey, Steven M; Bottlang, Michael

    2015-08-01

    Axial dynamization of an osteosynthesis construct can promote fracture healing. This biomechanical study evaluated a novel dynamic locking plate that derives symmetric axial dynamization by elastic suspension of locking holes within the plate. Standard locked and dynamic plating constructs were tested in a diaphyseal bridge-plating model of the femoral diaphysis to determine the amount and symmetry of interfragmentary motion under axial loading, and to assess construct stiffness under axial loading, torsion, and bending. Subsequently, constructs were loaded until failure to determine construct strength and failure modes. Finally, strength tests were repeated in osteoporotic bone surrogates. One body-weight axial loading of standard locked constructs produced asymmetric interfragmentary motion that was over three times smaller at the near cortex (0.1 ± 0.01 mm) than at the far cortex (0.32 ± 0.02 mm). Compared to standard locked constructs, dynamic plating constructs enhanced motion by 0.32 mm at the near cortex and by 0.33 mm at the far cortex and yielded a 77% lower axial stiffness (p < 0.001). Dynamic plating constructs were at least as strong as standard locked constructs under all test conditions. In conclusion, dynamic locking plates symmetrically enhance interfragmentary motion, deliver controlled axial dynamization, and are at least comparable in strength to standard locked constructs. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1218-1225, 2015. PMID:25721801

  11. Electrically-induced stresses and deflection in multiple plates

    SciTech Connect

    Hu, Jih-Perng; Tichler, P.R.

    1992-05-01

    Thermohydraulic tests are being planned at the High Flux Beam Reactor of Brookhaven National Laboratory, in which direct electrical heating of metal plates will simulate decay heating in parallel plate-type fuel elements. The required currents are high if plates are made of metal with a low electrical resistance, such as aluminum. These high currents will induce either attractive or repulsive forces between adjacent current-carrying plates. Such forces, if strong enough, will cause the plates to deflect and so change the geometry of the coolant channel between the plates. Since this is undesirable, an analysis has been made to evaluate the magnitude of the deflection and related stresses. In contrast to earlier publications in which either a concentrated or a uniform load was assumed, in this paper an exact force distribution on the plate is analytically solved and then used for stress and deflection calculations, assuming each plate to be a simply supported beam. Results indicate that due to superposition of the induced forces between plates in a multiple-and-parallel plate array, the maximum deflection and bending stress occur at the midpoint of the outermost plate. The maximum shear stress, which is inversely proportional to plate thickness, occurs at both ends of the outermost plate.

  12. Electrically-induced stresses and deflection in multiple plates

    SciTech Connect

    Hu, Jih-Perng; Tichler, P.R.

    1992-01-01

    Thermohydraulic tests are being planned at the High Flux Beam Reactor of Brookhaven National Laboratory, in which direct electrical heating of metal plates will simulate decay heating in parallel plate-type fuel elements. The required currents are high if plates are made of metal with a low electrical resistance, such as aluminum. These high currents will induce either attractive or repulsive forces between adjacent current-carrying plates. Such forces, if strong enough, will cause the plates to deflect and so change the geometry of the coolant channel between the plates. Since this is undesirable, an analysis has been made to evaluate the magnitude of the deflection and related stresses. In contrast to earlier publications in which either a concentrated or a uniform load was assumed, in this paper an exact force distribution on the plate is analytically solved and then used for stress and deflection calculations, assuming each plate to be a simply supported beam. Results indicate that due to superposition of the induced forces between plates in a multiple-and-parallel plate array, the maximum deflection and bending stress occur at the midpoint of the outermost plate. The maximum shear stress, which is inversely proportional to plate thickness, occurs at both ends of the outermost plate.

  13. Problem-Solving Software

    NASA Technical Reports Server (NTRS)

    1992-01-01

    CBR Express software solves problems by adapting sorted solutions to new problems specified by a user. It is applicable to a wide range of situations. The technology was originally developed by Inference Corporation for Johnson Space Center's Advanced Software Development Workstation. The project focused on the reuse of software designs, and Inference used CBR as part of the ACCESS prototype software. The commercial CBR Express is used as a "help desk" for customer support, enabling reuse of existing information when necessary. It has been adopted by several companies, among them American Airlines, which uses it to solve reservation system software problems.

  14. Earth's Decelerating Tectonic Plates

    SciTech Connect

    Forte, A M; Moucha, R; Rowley, D B; Quere, S; Mitrovica, J X; Simmons, N A; Grand, S P

    2008-08-22

    Space geodetic and oceanic magnetic anomaly constraints on tectonic plate motions are employed to determine a new global map of present-day rates of change of plate velocities. This map shows that Earth's largest plate, the Pacific, is presently decelerating along with several other plates in the Pacific and Indo-Atlantic hemispheres. These plate decelerations contribute to an overall, globally averaged slowdown in tectonic plate speeds. The map of plate decelerations provides new and unique constraints on the dynamics of time-dependent convection in Earth's mantle. We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data to show that time-dependent changes in mantle buoyancy forces can explain the deceleration of the major plates in the Pacific and Indo-Atlantic hemispheres.

  15. ASSEMBLY OF PARALLEL PLATES

    DOEpatents

    Groh, E.F.; Lennox, D.H.

    1963-04-23

    This invention is concerned with a rigid assembly of parallel plates in which keyways are stamped out along the edges of the plates and a self-retaining key is inserted into aligned keyways. Spacers having similar keyways are included between adjacent plates. The entire assembly is locked into a rigid structure by fastening only the outermost plates to the ends of the keys. (AEC)

  16. Accelerated plate tectonics.

    PubMed

    Anderson, D L

    1975-03-21

    The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence.

  17. Bending and buckling behavior analysis of foamed metal circular plate.

    PubMed

    Fan, Jian Ling; Ma, Lian Sheng; Zhang, Lu; De Su, Hou

    2016-01-01

    This paper establishes a density gradient model along the thickness direction of a circular plate made of foamed material. Based on the first shear deformation plate theory, the result is deduced that the foamed metal circular plate with graded density along thickness direction yields axisymmetric bending problem under the action of uniformly distributed load, and the analytical solution is obtained by solving the governing equation directly. The analyses on two constraint conditions of edge radial clamping and simply supported show that the density gradient index and external load may affect the axisymmetric bending behavior of the plate. Then, based on the classical plate theory, the paper analyzes the behavior of axisymmetric buckling under radial pressure applied on the circular plate. Shooting method is used to obtain the critical load, and the effects of gradient nature of material properties and boundary conditions on the critical load of the plate are analyzed. PMID:27339281

  18. Implant removal of osteosynthesis: the Dutch practice. Results of a survey

    PubMed Central

    2012-01-01

    Background The aim of this survey study was to evaluate the current opinion and practice of trauma and orthopaedic surgeons in the Netherlands in the removal of implants after fracture healing. Methods A web-based questionnaire consisting of 44 items was sent to all active members of the Dutch Trauma Society and Dutch Orthopaedic Trauma Society to determine their habits and opinions about implant removal. Results Though implant removal is not routinely done in the Netherlands, 89% of the Dutch surgeons agreed that implant removal is a good option in case of pain or functional deficits. Also infection of the implant or bone is one of the main reasons for removing the implant (> 90%), while making money was a motivation for only 1% of the respondents. In case of younger patients (< 40 years of age) only 34% of the surgeons agreed that metal implants should always be removed in this category. Orthopaedic surgeons are more conservative and differ in their opinion about this subject compared to general trauma surgeons (p = 0.002). Though the far majority removes elastic nails in children (95%). Most of the participants (56%) did not agree that leaving implants in is associated with an increased risk of fractures, infections, allergy or malignancy. Yet in case of the risk of fractures, residents all agreed to this statement (100%) whereas staff specialists disagreed for 71% (p < 0.001). According to 62% of the surgeons titanium plates are more difficult to remove than stainless steel, but 47% did not consider them safer to leave in situ compared to stainless steel. The most mentioned postoperative complications were wound infection (37%), unpleasant scarring (24%) and postoperative hemorraghe (19%). Conclusion This survey indicates that there is no general opinion about implant removal after fracture healing with a lack of policy guidelines in the Netherlands. In case of symptomatic patients a majority of the surgeons removes the implant, but this is not

  19. Solving Common Mathematical Problems

    NASA Technical Reports Server (NTRS)

    Luz, Paul L.

    2005-01-01

    Mathematical Solutions Toolset is a collection of five software programs that rapidly solve some common mathematical problems. The programs consist of a set of Microsoft Excel worksheets. The programs provide for entry of input data and display of output data in a user-friendly, menu-driven format, and for automatic execution once the input data has been entered.

  20. Solving Problems in Genetics

    ERIC Educational Resources Information Center

    Aznar, Mercedes Martinez; Orcajo, Teresa Ibanez

    2005-01-01

    A teaching unit on genetics and human inheritance using problem-solving methodology was undertaken with fourth-level Spanish Secondary Education students (15 year olds). The goal was to study certain aspects of the students' learning process (concepts, procedures and attitude) when using this methodology in the school environment. The change…

  1. What Is Problem Solving?

    ERIC Educational Resources Information Center

    Martinez, Michael E.

    1998-01-01

    Many important human activities involve accomplishing goals without a script. There is no formula for true problem-solving. Heuristic, cognitive "rules of thumb" are the problem-solver's best guide. Learners should understand heuristic tools such as means-end analysis, working backwards, successive approximation, and external representation. Since…

  2. Problem Solving by Design

    ERIC Educational Resources Information Center

    Capobianco, Brenda M.; Tyrie, Nancy

    2009-01-01

    In a unique school-university partnership, methods students collaborated with fifth graders to use the engineering design process to build their problem-solving skills. By placing the problem in the context of a client having particular needs, the problem took on a real-world appeal that students found intriguing and inviting. In this article, the…

  3. Mathematics as Problem Solving.

    ERIC Educational Resources Information Center

    Soifer, Alexander

    This book contains about 200 problems. It is suggested that it be used by students, teachers or anyone interested in exploring mathematics. In addition to a general discussion on problem solving, there are problems concerned with number theory, algebra, geometry, and combinatorics. (PK)

  4. Problem Solving in Electricity.

    ERIC Educational Resources Information Center

    Caillot, Michel; Chalouhi, Elias

    Two studies were conducted to describe how students perform direct current (D-C) circuit problems. It was hypothesized that problem solving in the electricity domain depends largely on good visual processing of the circuit diagram and that this processing depends on the ability to recognize when two or more electrical components are in series or…

  5. Universal Design Problem Solving

    ERIC Educational Resources Information Center

    Sterling, Mary C.

    2004-01-01

    Universal design is made up of four elements: accessibility, adaptability, aesthetics, and affordability. This article addresses the concept of universal design problem solving through experiential learning for an interior design studio course in postsecondary education. Students' experiences with clients over age 55 promoted an understanding of…

  6. Problem Solving with Patents

    ERIC Educational Resources Information Center

    Moore, Jerilou; Sumrall, William J.

    2008-01-01

    Exploring our patent system is a great way to engage students in creative problem solving. As a result, the authors designed a teaching unit that uses the study of patents to explore one avenue in which scientists and engineers do science. Specifically, through the development of an idea, students learn how science and technology are connected.…

  7. Electric Current Solves Mazes

    ERIC Educational Resources Information Center

    Ayrinhac, Simon

    2014-01-01

    We present in this work a demonstration of the maze-solving problem with electricity. Electric current flowing in a maze as a printed circuit produces Joule heating and the right way is instantaneously revealed with infrared thermal imaging. The basic properties of electric current can be discussed in this context, with this challenging question:…

  8. Inquiry and Problem Solving.

    ERIC Educational Resources Information Center

    Thorson, Annette, Ed.

    1999-01-01

    This issue of ENC Focus focuses on the topic of inquiry and problem solving. Featured articles include: (1) "Inquiry in the Everyday World of Schools" (Ronald D. Anderson); (2) "In the Cascade Reservoir Restoration Project Students Tackle Real-World Problems" (Clint Kennedy with Advanced Biology Students from Cascade High School); (3) "Project…

  9. Preparing for Problem Solving

    ERIC Educational Resources Information Center

    Holden, Becky

    2007-01-01

    Seeking more effective mathematics instruction, this author decided to incorporate Cognitively Guided Instruction (CGI) into first-grade classroom lessons. Students in CGI mathematics classrooms are prompted to use their prior knowledge to solve new problems, establish cognitive structures to which new learning can be connected, and be driven by…

  10. Solving Problems through Circles

    ERIC Educational Resources Information Center

    Grahamslaw, Laura; Henson, Lisa H.

    2015-01-01

    Several problem-solving interventions that utilise a "circle" approach have been applied within the field of educational psychology, for example, Circle Time, Circle of Friends, Sharing Circles, Circle of Adults and Solution Circles. This research explored two interventions, Solution Circles and Circle of Adults, and used thematic…

  11. On Solving Linear Recurrences

    ERIC Educational Resources Information Center

    Dobbs, David E.

    2013-01-01

    A direct method is given for solving first-order linear recurrences with constant coefficients. The limiting value of that solution is studied as "n to infinity." This classroom note could serve as enrichment material for the typical introductory course on discrete mathematics that follows a calculus course.

  12. Circumference and Problem Solving.

    ERIC Educational Resources Information Center

    Blackburn, Katie; White, David

    The concept of pi is one of great importance to all developed civilization and one that can be explored and mastered by elementary students through an inductive and problem-solving approach. Such an approach is outlined and discussed. The approach involves the following biblical quotation: "And he made a moltin sea ten cubits from one brim to the…

  13. Introspection in Problem Solving

    ERIC Educational Resources Information Center

    Jäkel, Frank; Schreiber, Cornell

    2013-01-01

    Problem solving research has encountered an impasse. Since the seminal work of Newell und Simon (1972) researchers do not seem to have made much theoretical progress (Batchelder and Alexander, 2012; Ohlsson, 2012). In this paper we argue that one factor that is holding back the field is the widespread rejection of introspection among cognitive…

  14. [Problem Solving Activities.

    ERIC Educational Resources Information Center

    Wisconsin Univ. - Stout, Menomonie. Center for Vocational, Technical and Adult Education.

    The teacher directed problem solving activities package contains 17 units: Future Community Design, Let's Build an Elevator, Let's Construct a Catapult, Let's Design a Recreational Game, Let's Make a Hand Fishing Reel, Let's Make a Wall Hanging, Let's Make a Yo-Yo, Marooned in the Past, Metrication, Mousetrap Vehicles, The Multi System…

  15. Preoperative Planning of Virtual Osteotomies Followed by Fabrication of Patient Specific Reconstruction Plate for Secondary Correction and Fixation of Displaced Bilateral Mandibular Body Fracture.

    PubMed

    Thor, Andreas

    2016-06-01

    This paper describes the course of treatment of a severely diplaced bilateral mandibular body fracture, where the first osteosynthesis failed. The subject developed an open bite due to a posterior rotation of the distal part of the mandible and anterior rotation of the proximal parts of the mandible. This situation was evaluated with CBCT and the facial skeleton was segmented using computer software. Correct occlusion was virtually established by bilateral virtual osteotomies in the fracture areas of the mandible. After segmentation, the mandible was virtually rotated back into position and the open bite was closed. A patient specific mandibular reconstruction plate was outlined and fabricated from the new virtual situation and the plate was thereafter installed utilizing the preoperative plan. Osteotomy- and drill-guides was used and thus simplified the surgery resulting in uneventful healing. Virtual planning and patient specific implants and guides were valuable in this case of secondary reconstructive trauma surgery. PMID:27162581

  16. Absolute plate velocities from seismic anisotropy: Importance of correlated errors

    NASA Astrophysics Data System (ADS)

    Zheng, Lin; Gordon, Richard G.; Kreemer, Corné

    2014-09-01

    The errors in plate motion azimuths inferred from shear wave splitting beneath any one tectonic plate are shown to be correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two-tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining relative plate angular velocities to consistency with the MORVEL relative plate angular velocities. Our preferred set of angular velocities, SKS-MORVEL, is determined from the poles from eight plates weighted proportionally to the root-mean-square velocity of each plate. SKS-MORVEL indicates that eight plates (Amur, Antarctica, Caribbean, Eurasia, Lwandle, Somalia, Sundaland, and Yangtze) have angular velocities that differ insignificantly from zero. The net rotation of the lithosphere is 0.25 ± 0.11° Ma-1 (95% confidence limits) right handed about 57.1°S, 68.6°E. The within-plate dispersion of seismic anisotropy for oceanic lithosphere (σ = 19.2°) differs insignificantly from that for continental lithosphere (σ = 21.6°). The between-plate dispersion, however, is significantly smaller for oceanic lithosphere (σ = 7.4°) than for continental lithosphere (σ = 14.7°). Two of the slowest-moving plates, Antarctica (vRMS = 4 mm a-1, σ = 29°) and Eurasia (vRMS = 3 mm a-1, σ = 33°), have two of the largest within-plate dispersions, which may indicate that a plate must move faster than ≈ 5 mm a-1 to result in seismic anisotropy useful for estimating plate motion. The tendency of observed azimuths on the Arabia plate to be counterclockwise of plate motion may provide information about the direction and amplitude of superposed asthenospheric flow or about anisotropy in the lithospheric mantle.

  17. Rotatable shear plate interferometer

    DOEpatents

    Duffus, Richard C.

    1988-01-01

    A rotatable shear plate interferometer comprises a transparent shear plate mounted obliquely in a tubular supporting member at 45.degree. with respect to its horizontal center axis. This tubular supporting member is supported rotatably around its center axis and a collimated laser beam is made incident on the shear plate along this center axis such that defocus in different directions can be easily measured.

  18. Plating Tank Control Software

    1998-03-01

    The Plating Tank Control Software is a graphical user interface that controls and records plating process conditions for plating in high aspect ratio channels that require use of low current and long times. The software is written for a Pentium II PC with an 8 channel data acquisition card, and the necessary shunt resistors for measuring currents in the millampere range.

  19. Study on plate silencer with general boundary conditions

    NASA Astrophysics Data System (ADS)

    Liu, Gongmin; Zhao, Xiaochen; Zhang, Wenping; Li, Shuaijun

    2014-09-01

    A plate silencer consists of an expansion chamber with two side-branch rigid cavities covered by plates. Previous studies showed that, in a duct, the introduction of simply supported or clamped plates into an air conveying system could achieve broadband quieting from low to medium frequencies. In this study, analytical formulation is extended to the plate silencer with general boundary conditions. A set of static beam functions, which are a combination of sine series and third-order polynomial, is employed as the trial functions of the plate vibration velocity. Greens function and Kirchhoff-Helmholtz integral are used to solve the sound radiation in the duct and the cavity, and then the vibration velocity of the plate is obtained. Having obtained the vibration velocity, the pressure perturbations induced by the plate oscillation and the transmission loss are found. Optimization is carried out in order to obtain the widest stopband. The transmission loss calculated by the analytical method agrees closely with the result of the finite element method simulation. Further studies with regard to the plate under several different classical boundary conditions based on the validated model show that a clamped-free plate silencer has the worst stopband. Attempts to release the boundary restriction of the plate are also made to study its effect on sound reflection. Results show that a softer end for a clamped-clamped plate silencer helps increase the optimal bandwidth, while the same treatment for simply supported plate silencer will result in performance degradation.

  20. An improved plating process

    NASA Technical Reports Server (NTRS)

    Askew, John C.

    1994-01-01

    An alternative to the immersion process for the electrodeposition of chromium from aqueous solutions on the inside diameter (ID) of long tubes is described. The Vessel Plating Process eliminates the need for deep processing tanks, large volumes of solutions, and associated safety and environmental concerns. Vessel Plating allows the process to be monitored and controlled by computer thus increasing reliability, flexibility and quality. Elimination of the trivalent chromium accumulation normally associated with ID plating is intrinsic to the Vessel Plating Process. The construction and operation of a prototype Vessel Plating Facility with emphasis on materials of construction, engineered and operational safety and a unique system for rinse water recovery are described.

  1. Angular shear plate

    SciTech Connect

    Ruda, Mitchell C.; Greynolds, Alan W.; Stuhlinger, Tilman W.

    2009-07-14

    One or more disc-shaped angular shear plates each include a region thereon having a thickness that varies with a nonlinear function. For the case of two such shear plates, they are positioned in a facing relationship and rotated relative to each other. Light passing through the variable thickness regions in the angular plates is refracted. By properly timing the relative rotation of the plates and by the use of an appropriate polynomial function for the thickness of the shear plate, light passing therethrough can be focused at variable positions.

  2. Unstable-unit tensegrity plate: modeling and design

    NASA Astrophysics Data System (ADS)

    Zaslavsky, Ron; de Oliveira, Mauricio C.; Skelton, Robert E.

    2003-08-01

    A new topology for a prestressed tensegrity plate, the unstable-unit tensegrity plate (UUTP), is introduced, together with a detailed algorithm for its design. The plate is a truss made of strings (flexible elements) and bars (rigid elements), which are loaded in tension and compression, respectively, where bars do not touch each other. Given the outline dimensions of the desired plate, and the number of bars along the plate's width and length, the algorithm solves for the nodes' positions and the prestress forces that make a plate in equilibrium. This is done by solving a non-linear matrix equation via Newton's method. This equation reflects static equilibrium conditions. We've designed several such plates, proving the feasibility of the proposed topology and the effectiveness of its design algorithm. Two such plates are characterized in detail, both statically and dynamically (via simulation). The proposed algorithm may be extended to solve for other tensegrity structures having different topologies and/or different shapes. The UUTP may be used as a building block of many types of structures, both uncontrolled and controlled, either large-scale or miniature-scale.

  3. Multicolor printing plate joining

    NASA Technical Reports Server (NTRS)

    Waters, W. J. (Inventor)

    1984-01-01

    An upper plate having ink flow channels and a lower plate having a multicolored pattern are joined. The joining is accomplished without clogging any ink flow paths. A pattern having different colored parts and apertures is formed in a lower plate. Ink flow channels each having respective ink input ports are formed in an upper plate. The ink flow channels are coated with solder mask and the bottom of the upper plate is then coated with solder. The upper and lower plates are pressed together at from 2 to 5 psi and heated to a temperature of from 295 F to 750 F or enough to melt the solder. After the plates have cooled and the pressure is released, the solder mask is removed from the interior passageways by means of a liquid solvent.

  4. Geologically current plate motions

    NASA Astrophysics Data System (ADS)

    DeMets, Charles; Gordon, Richard G.; Argus, Donald F.

    2010-04-01

    We describe best-fitting angular velocities and MORVEL, a new closure-enforced set of angular velocities for the geologically current motions of 25 tectonic plates that collectively occupy 97 per cent of Earth's surface. Seafloor spreading rates and fault azimuths are used to determine the motions of 19 plates bordered by mid-ocean ridges, including all the major plates. Six smaller plates with little or no connection to the mid-ocean ridges are linked to MORVEL with GPS station velocities and azimuthal data. By design, almost no kinematic information is exchanged between the geologically determined and geodetically constrained subsets of the global circuit-MORVEL thus averages motion over geological intervals for all the major plates. Plate geometry changes relative to NUVEL-1A include the incorporation of Nubia, Lwandle and Somalia plates for the former Africa plate, Capricorn, Australia and Macquarie plates for the former Australia plate, and Sur and South America plates for the former South America plate. MORVEL also includes Amur, Philippine Sea, Sundaland and Yangtze plates, making it more useful than NUVEL-1A for studies of deformation in Asia and the western Pacific. Seafloor spreading rates are estimated over the past 0.78 Myr for intermediate and fast spreading centres and since 3.16 Ma for slow and ultraslow spreading centres. Rates are adjusted downward by 0.6-2.6mmyr-1 to compensate for the several kilometre width of magnetic reversal zones. Nearly all the NUVEL-1A angular velocities differ significantly from the MORVEL angular velocities. The many new data, revised plate geometries, and correction for outward displacement thus significantly modify our knowledge of geologically current plate motions. MORVEL indicates significantly slower 0.78-Myr-average motion across the Nazca-Antarctic and Nazca-Pacific boundaries than does NUVEL-1A, consistent with a progressive slowdown in the eastward component of Nazca plate motion since 3.16 Ma. It also

  5. Is There Really A North American Plate?

    NASA Astrophysics Data System (ADS)

    Krill, A.

    2011-12-01

    elsewhere, such as S.J. Shand (1933), E.B. Bailey (1939), and Arthur Holmes (1944), presented continental drift as a working hypothesis that could elegantly solve important geological problems. Americans were preconditioned to dislike continental drift theory, ever since James Dwight Dana taught in his Manual of Geology (1863...1895) that North America was the type continent of the world, and that it had stood alone since earliest time. Such beliefs sometimes trump geologic evidence. As noted by Stephen Jay Gould (1999) Sigmund Freud had much insight into the psychology of scientific revolutions: they involve a scientific development that shows humans to have lesser status than previously perceived. In the Copernican revolution (geocentrism vs. heliocentrism) humans no longer inhabited the center of the universe. In the Darwinian revolution (creationism vs. evolutionism) humans were no longer uniquely created. In the Wegenerian revolution (fixism vs. mobilism) North America was no longer uniquely created; it was just other fragment from Pangaea. North American geologists were pleased when Press & Siever gave them their own lithospheric plate. Being a global-tectonic killjoy, I would like to take away that small consolation as well. Or at least pose the question: Is there really a North American Plate?

  6. Hypervelocity plate acceleration

    SciTech Connect

    Marsh, S.P.; Tan, T.H.

    1991-01-01

    Shock tubes have been used to accelerate 1.5-mm-thick stainless steel plates to high velocity while retaining their integrity. The fast shock tubes are 5.1-cm-diameter, 15.2-cm-long cylinders of PBX-9501 explosive containing a 1.1-cm-diameter cylindrical core of low-density polystyrene foam. The plates have been placed directly in contact with one face of the explosive system. Plane-wave detonation was initiated on the opposite face. A Mach disk was formed in the imploding styrofoam core, which provided the impulse required to accelerate the metal plate to high velocity. Parametric studies were made on this system to find the effect of varying plate metal, plate thickness, foam properties, and addition of a barrel. A maximum plate velocity of 9.0 km/s has been observed. 6 refs., 17 figs.

  7. On Solving Kepler's Equation

    NASA Astrophysics Data System (ADS)

    Taff, L. G.; Brennan, T. A.

    1989-06-01

    Intrigued by the recent advances in research on solving Kepler's equation, we have attacked the problem too. Our contributions emphasize the unified derivation of all known bounds and several starting values, a proof of the optimality of these bounds, a very thorough numerical exploration of a large variety of starting values and solution techniques in both mean anomaly/eccentricity space and eccentric anomaly/eccentricity space, and finally the best and simplest starting value/solution algorithm: M + e and Wegstein's secant modification of the method of successive substitutions. The very close second is Broucke's bounds coupled with Newton's second-order scheme.

  8. Solving crimes with hypnosis.

    PubMed

    Wester, William C; Hammond, D Corydon

    2011-04-01

    Following a brief review of the literature on hypnosis and memory, this paper overviews the procedures that are used in conducting forensic hypnosis interviews. Ten forensic hypnosis cases are then described. These real world cases are in stark contrast to research done in an artificial laboratory setting where the information to be recalled lacks personal relevance and was not associated with emotionally arousing situations. These cases illustrate how forensic hypnosis can result in obtaining important additional investigative leads which lead to the solving of crimes.

  9. Plating methods, a survey

    NASA Technical Reports Server (NTRS)

    Berkowitz, J. B.; Emerson, N. H.

    1972-01-01

    Results are presented of a comprehensive search of the literature available, much of which has been generated by the research centers of NASA and its contractors, on plating and coating methods and techniques. Methods covered included: (1) electroplating from aqueous solutions; (2) electroplating from nonaqueous solutions; (3) electroplating from fused-salt baths; (4) electroforming; (5) electroless plating, immersion plating, and mirroring; (6) electroplating from gaseous plasmas; and (7) anodized films and conversion coatings.

  10. GOLD PLATING PROCESS

    DOEpatents

    Seegmiller, R.

    1957-08-01

    An improved bath is reported for plating gold on other metals. The composition of the plating bath is as follows: Gold cyanide from about 15 to about 50 grams, potassium cyanide from about 70 to about 125 grams, and sulfonated castor oil from about 0.1 to about 10 cc. The gold plate produced from this bath is smooth, semi-hard, and nonporous.

  11. PLATES WITH OXIDE INSERTS

    DOEpatents

    West, J.M.; Schumar, J.F.

    1958-06-10

    Planar-type fuel assemblies for nuclear reactors are described, particularly those comprising fuel in the oxide form such as thoria and urania. The fuel assembly consists of a plurality of parallel spaced fuel plate mennbers having their longitudinal side edges attached to two parallel supporting side plates, thereby providing coolant flow channels between the opposite faces of adjacent fuel plates. The fuel plates are comprised of a plurality of longitudinally extending tubular sections connected by web portions, the tubular sections being filled with a plurality of pellets of the fuel material and the pellets being thermally bonded to the inside of the tubular section by lead.

  12. Inversion for the driving forces of plate tectonics

    NASA Technical Reports Server (NTRS)

    Richardson, R. M.

    1983-01-01

    Inverse modeling techniques have been applied to the problem of determining the roles of various forces that may drive and resist plate tectonic motions. Separate linear inverse problems have been solved to find the best fitting pole of rotation for finite element grid point velocities and to find the best combination of force models to fit the observed relative plate velocities for the earth's twelve major plates using the generalized inverse operator. Variance-covariance data on plate motion have also been included. Results emphasize the relative importance of ridge push forces in the driving mechanism. Convergent margin forces are smaller by at least a factor of two, and perhaps by as much as a factor of twenty. Slab pull, apparently, is poorly transmitted to the surface plate as a driving force. Drag forces at the base of the plate are smaller than ridge push forces, although the sign of the force remains in question.

  13. Inverse methods-based estimation of plate coupling in a plate motion model governed by mantle flow

    NASA Astrophysics Data System (ADS)

    Ratnaswamy, V.; Stadler, G.; Gurnis, M.

    2013-12-01

    Plate motion is primarily controlled by buoyancy (slab pull) which occurs at convergent plate margins where oceanic plates undergo deformation near the seismogenic zone. Yielding within subducting plates, lateral variations in viscosity, and the strength of seismic coupling between plate margins likely have an important control on plate motion. Here, we wish to infer the inter-plate coupling for different subduction zones, and develop a method for inferring it as a PDE-constrained optimization problem, where the cost functional is the misfit in plate velocities and is constrained by the nonlinear Stokes equation. The inverse models have well resolved slabs, plates, and plate margins in addition to a power law rheology with yielding in the upper mantle. Additionally, a Newton method is used to solve the nonlinear Stokes equation with viscosity bounds. We infer plate boundary strength using an inexact Gauss-Newton method with line search for backtracking. Each inverse model is applied to two simple 2-D scenarios (each with three subduction zones), one with back-arc spreading and one without. For each case we examine the sensitivity of the inversion to the amount of surface velocity used: 1) full surface velocity data and 2) surface velocity data simplified using a single scalar average (2-D equivalent to an Euler pole) for each plate. We can recover plate boundary strength in each case, even in the presence of highly nonlinear flow with extreme variations in viscosity. Additionally, we ascribe an uncertainty in each plate's velocity and perform an uncertainty quantification (UQ) through the Hessian of the misfit in plate velocities. We find that as plate boundaries become strongly coupled, the uncertainty in the inferred plate boundary strength decreases. For very weak, uncoupled subduction zones, the uncertainty of inferred plate margin strength increases since there is little sensitivity between plate margin strength and plate velocity. This result is significant

  14. A Mindlin-Reissner variational principle to analyze the behavior of moderately thick plates

    SciTech Connect

    Carnicer, R.S. ); Alliney, S. )

    1989-11-01

    In the present work a method to solve the plate behavior under the assumption of the Mindlin plate theory is analyzed by means of finite element techniques, avoiding the tendency of the thin element to lock when the thickness of the plates becomes very small. A different formulation is developed from the Mindlin-Reissner principle for general boundary conditions. Numerical examples to evaluate the noninfluence of locking on clamped and simple support plates are calculated.

  15. Numerical modelling of instantaneous plate tectonics

    NASA Technical Reports Server (NTRS)

    Minster, J. B.; Haines, E.; Jordan, T. H.; Molnar, P.

    1974-01-01

    Assuming lithospheric plates to be rigid, 68 spreading rates, 62 fracture zones trends, and 106 earthquake slip vectors are systematically inverted to obtain a self-consistent model of instantaneous relative motions for eleven major plates. The inverse problem is linearized and solved iteratively by a maximum-likelihood procedure. Because the uncertainties in the data are small, Gaussian statistics are shown to be adequate. The use of a linear theory permits (1) the calculation of the uncertainties in the various angular velocity vectors caused by uncertainties in the data, and (2) quantitative examination of the distribution of information within the data set. The existence of a self-consistent model satisfying all the data is strong justification of the rigid plate assumption. Slow movement between North and South America is shown to be resolvable.

  16. Management of lower limb fractures in polytrauma patients with delayed referral in a mass disaster. The role of the Ilizarov method in conversion osteosynthesis.

    PubMed

    Dhar, Shabir Ahmed; Butt, Mohammed Farooq; Hussain, Anwar; Mir, Mohammed Ramzan; Halwai, Manzoor Ahmed; Kawoosa, Altaf Ahmed

    2008-08-01

    Polytrauma cases in mass disasters present several challenges to the orthopaedic surgeon. Delayed referral, multisystem involvement and the requirement to manage coexisting injuries by interhospital transfer often make infection an inevitable risk. 28 patients with polytrauma were studied after being referred after being recovered from the debris of their homes in the Kashmir earthquake. All patients were referred more than 24h after sustaining their injuries. The lower limb fractures were fixed by external fixators in all these cases before interhospital transfer for the management of their co existing injuries. Return referral to the orthopaedic facility occurred after an average of 25 days. All cases were converted to Ilizarov fixation. The results bear out the fact that the Ilizarov method may be well suited for conversion osteosynthesis of lower limb fractures in polytrauma cases.

  17. Solving Differential Equations in R: Package deSolve

    EPA Science Inventory

    In this paper we present the R package deSolve to solve initial value problems (IVP) written as ordinary differential equations (ODE), differential algebraic equations (DAE) of index 0 or 1 and partial differential equations (PDE), the latter solved using the method of lines appr...

  18. Earthquakes and plate tectonics

    USGS Publications Warehouse

    Spall, H.

    1977-01-01

    An explanation is to be found in plate tectonics, a concept which has revolutionized thinking in the Earth sciences in the last 10 years. The theory of plate tectonics combines many of the ideas about continental drift (originally proposed in 1912 by Alfred Wegener in Germany) and sea-floor spreading (suggested originally by Harry Hess of Princeton University). 

  19. Blue Willow Story Plates

    ERIC Educational Resources Information Center

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  20. The polarizability and the capacitance change of a bounded object in a parallel plate capacitor

    NASA Astrophysics Data System (ADS)

    Kristensson, Gerhard

    2012-09-01

    A method for solving the change in capacitance (or charge) if an object is introduced in a parallel plate capacitor is developed. The integral representation of the potential is exploited in a systematic way to solve the potential everywhere inside the capacitor. In particular, the change in capacitance is extracted. The method shows similarities with the null field approach for solving dynamic problems.

  1. Instability of a cantilevered flexible plate in viscous channel flow

    NASA Astrophysics Data System (ADS)

    Balint, T. S.; Lucey, A. D.

    2005-10-01

    The stability of a flexible cantilevered plate in viscous channel flow is studied as a representation of the dynamics of the human upper airway. The focus is on instability mechanisms of the soft palate (flexible plate) that cause airway blockage during sleep. We solve the Navier Stokes equations for flow with Reynolds numbers up to 1500 fully coupled with the dynamics of the plate motion solved using finite-differences. The study is 2-D and based upon linearized plate mechanics. When both upper and lower airways are open, the plate is found to lose its stability through a flutter mechanism and a critical Reynolds number exists. When one airway is closed, the plate principally loses its stability through a divergence mechanism and a critical flow speed exists. However, below the divergence-onset flow speed, flutter can exist for low levels of structural damping in the flexible plate. Our results serve to extend understanding of flow-induced instability of cantilevered flexible plates and will ultimately improve the diagnosis and treatment of upper-airway disorders.

  2. Turbine vane plate assembly

    SciTech Connect

    Schiavo Jr., Anthony L.

    2006-01-10

    A turbine vane assembly includes a turbine vane having first and second shrouds with an elongated airfoil extending between. Each end of the airfoil transitions into a shroud at a respective junction. Each of the shrouds has a plurality of cooling passages, and the airfoil has a plurality of cooling passages extending between the first and second shrouds. A substantially flat inner plate and an outer plate are coupled to each of the first and second shrouds so as to form inner and outer plenums. Each inner plenum is defined between at least the junction and the substantially flat inner plate; each outer plenum is defined between at least the substantially flat inner plate and the outer plate. Each inner plenum is in fluid communication with a respective outer plenum through at least one of the cooling passages in the respective shroud.

  3. Principal visual word discovery for automatic license plate detection.

    PubMed

    Zhou, Wengang; Li, Houqiang; Lu, Yijuan; Tian, Qi

    2012-09-01

    License plates detection is widely considered a solved problem, with many systems already in operation. However, the existing algorithms or systems work well only under some controlled conditions. There are still many challenges for license plate detection in an open environment, such as various observation angles, background clutter, scale changes, multiple plates, uneven illumination, and so on. In this paper, we propose a novel scheme to automatically locate license plates by principal visual word (PVW), discovery and local feature matching. Observing that characters in different license plates are duplicates of each other, we bring in the idea of using the bag-of-words (BoW) model popularly applied in partial-duplicate image search. Unlike the classic BoW model, for each plate character, we automatically discover the PVW characterized with geometric context. Given a new image, the license plates are extracted by matching local features with PVW. Besides license plate detection, our approach can also be extended to the detection of logos and trademarks. Due to the invariance virtue of scale-invariant feature transform feature, our method can adaptively deal with various changes in the license plates, such as rotation, scaling, illumination, etc. Promising results of the proposed approach are demonstrated with an experimental study in license plate detection.

  4. Geogebra for Solving Problems of Physics

    NASA Astrophysics Data System (ADS)

    Kllogjeri, Pellumb; Kllogjeri, Adrian

    Today is highly speed progressing the computer-based education, which allowes educators and students to use educational programming language and e-tutors to teach and learn, to interact with one another and share together the results of their work. In this paper we will be concentrated on the use of GeoGebra programme for solving problems of physics. We have brought an example from physics of how can be used GeoGebra for finding the center of mass(centroid) of a picture(or system of polygons). After the problem is solved graphically, there is an application of finding the center of a real object(a plate)by firstly, scanning the object and secondly, by inserting its scanned picture into the drawing pad of GeoGebra window and lastly, by finding its centroid. GeoGebra serve as effective tool in problem-solving. There are many other applications of GeoGebra in the problems of physics, and many more in different fields of mathematics.

  5. Osteosynthesis of fragility fractures.

    PubMed

    Tarantino, Umberto; Iundusi, Riccardo; Lecce, Domenico; Tempesta, Valerio; Perrone, Fabio Luigi; Rao, Cecilia; Cerocchi, Irene; Gasbarra, Elena

    2011-04-01

    The deepening knowledge about bone pathophysiology, together with the development of less invasive bone implants, fitted for the treatment of fragility fractures, the continuous advances in the creation of osteoconductive and osteoinductive biomaterials, the availability of bone active agents, capable of modulating fracture healing, actually represent the orthopaedic "weapons" to improve the surgical outcome and quality of life in patients with osteoporosis.

  6. Plating To Reinforce Welded Joints

    NASA Technical Reports Server (NTRS)

    Otousa, J. E.

    1982-01-01

    Electrodeposition used to strengthen welded joints gouged, nicked, or suffered other mechanical damage. Plating cell, typically of acrylic plastic such as poly (Methylmetacrylate), is assembled around part to be plated. Areas not to be plated are masked with plater's tape. Weld area is plated in standard nickel-plating process.

  7. Problem Solving and Beginning Programming.

    ERIC Educational Resources Information Center

    McAllister, Alan

    Based on current models of problem solving within cognitive psychology, this study focused on the spontaneous problem solving strategies used by children as they first learned LOGO computer programming, and on strategy transformations that took place during the problem solving process. The research consisted of a six weeks programming training…

  8. Geometrically nonlinear behavior of piezoelectric laminated plates

    NASA Astrophysics Data System (ADS)

    Rabinovitch, Oded

    2005-08-01

    The geometrically nonlinear behavior of piezo-laminated plates actuated with isotropic or anisotropic piezoelectric layers is analytically investigated. The analytical model is derived using the variational principle of virtual work along with the lamination and plate theories, the von Karman large displacement and moderate rotation kinematic relations, and the anisotropic piezoelectric constitutive laws. A solution strategy that combines the approach of the method of lines, the advantages of the finite element concept, and the variational formulation is developed. This approach yields a set of nonlinear ordinary differential equations with nonlinear boundary conditions, which are solved using the multiple-shooting method. Convergence and verification of the model are examined through comparison with linear and nonlinear results of other approximation methods. The nonlinear response of two active plate structures is investigated numerically. The first plate is actuated in bending using monolithic piezoceramic layers and the second one is actuated in twist using macro-fiber composites. The results quantitatively reveal the complicated in-plane stress state associated with the piezoelectric actuation and the geometrically nonlinear coupling of the in-plane and out-of-plane responses of the plate. The influence of the nonlinear effects ranges from significant stiffening in certain combinations of electrical loads and boundary conditions to amplifications of the induced deflections in others. The paper closes with a summary and conclusions.

  9. Fracture of composite plates containing periodic buffer strips

    NASA Technical Reports Server (NTRS)

    Erdogan, F.; Bakioglu, M.

    1974-01-01

    Fracture of a composite plate which consists of perfectly bonded parallel load carrying laminates and buffer strips is considered. Fatigue cracks appear and spread in main laminates or in buffer strips or in both perpendicular to the interfaces. The external load is applied to the plate parallel to the strips and away from the crack region. The problem is solved for fully imbedded cracks and for broken laminates or strips. Corresponding stress intensity factors are calculated.

  10. Earthquakes and plate tectonics.

    USGS Publications Warehouse

    Spall, H.

    1982-01-01

    Earthquakes occur at the following three kinds of plate boundary: ocean ridges where the plates are pulled apart, margins where the plates scrape past one another, and margins where one plate is thrust under the other. Thus, we can predict the general regions on the earth's surface where we can expect large earthquakes in the future. We know that each year about 140 earthquakes of magnitude 6 or greater will occur within this area which is 10% of the earth's surface. But on a worldwide basis we cannot say with much accuracy when these events will occur. The reason is that the processes in plate tectonics have been going on for millions of years. Averaged over this interval, plate motions amount to several mm per year. But at any instant in geologic time, for example the year 1982, we do not know, exactly where we are in the worldwide cycle of strain build-up and strain release. Only by monitoring the stress and strain in small areas, for instance, the San Andreas fault, in great detail can we hope to predict when renewed activity in that part of the plate tectonics arena is likely to take place. -from Author

  11. Lohse's historic plate archive

    NASA Astrophysics Data System (ADS)

    Tsvetkov, M.; Tsvetkova, K.; Richter, G.; Scholz, G.; Böhm, P.

    The description and the analysis of Oswald Lohse's astrophotographic plates, collected at the Astrophysical Observatory Potsdam in the period 1879 - 1889, are presented. 67 plates of the archive, taken with the greatest instrument of the observatory at that time - the refractor (D = 0.30 m, F = 5.40 m, scale = 38''/mm) and with the second heliographic objective (D = 0.13 m, F = 1.36 m, scale = 152''/mm) - - survived two world wars in relative good condition. The plate emulsions are from different manufacturers in the beginning of astrophotography (Gädicke, Schleussner, Beernaert, etc.). The sizes of the plates are usually 9x12 cm2, which corresponds to fields of 1.2deg and 5deg respectively for each instrument mentioned above. The average limiting magnitude is 13.0(pg). Besides of the plates received for technical experiments (work on photographic processes, testing of new instruments and methods of observations), the scientific observations follow programs for studies of planet surfaces, bright stars, some double stars, stellar clusters and nebulous objects. Lohse's archive is included into the Wide Field Plate Database (http://www.skyarchive.org) as the oldest systematic one, covering the fields of Orion (M42/43), Pleiades, h & chi Persei, M37, M3, M11, M13, M92, M31, etc. With the PDS 2020 GM+ microdensitometer of Münster University 10 archive plates were digitized.

  12. Computational valve plate design

    NASA Astrophysics Data System (ADS)

    Kalbfleisch, Paul

    Axial piston machines are widely used in many industries for their designs compactness, flexibility in power transfer, variable flow rate, and high efficiencies as compared to their manufacturing costs. One important component of all axial piston machines that is a very influential on the performance of the unit is the valve plate. The aim of this research is to develop a design methodology that is general enough to design all types of valve plates and the simple enough not to require advanced technical knowledge from the user. A new style of valve plate designs has been developed that comprehensively considers all previous design techniques and does not require significant changes to the manufacturing processes of valve plates. The design methodology utilizes a previously developed accurate computer model of the physical phenomenon. This allows the precise optimization of the valve plate design through the use of simulations rather than expensive trial and error processes. The design of the valve plate is clarified into the form of an optimization problem. This formulation into an optimization problem has motivated the selection of an optimization algorithm that satisfies the requirements of the design. The proposed design methodology was successfully tested in a case study in the shown to be very successful in improving required performance of the valve plate design.

  13. Solving the Antibiotic Crisis.

    PubMed

    Wright, Gerard D

    2015-02-13

    Antibiotics are essential for both treating and preventing infectious diseases. Paradoxically, despite their importance as pillars of modern medicine, we are in danger of losing antibiotics because of the evolution and dissemination of resistance mechanisms throughout all pathogenic microbes. This fact, coupled with an inability to bring new drugs to market at a pace that matches resistance, has resulted in a crisis of global proportion. Solving this crisis requires the actions of many stakeholders, but chemists, chemical biologists, and microbiologists must drive the scientific innovation that is required to maintain our antibiotic arsenal. This innovation requires (1) a deep understanding of the evolution and reservoirs of resistance; (2) full knowledge of the molecular mechanisms of antibiotic action and resistance; (3) the discovery of chemical and genetic probes of antibiotic action and resistance; (4) the integration of systems biology into antibiotic discovery; and (5) the discovery of new antimicrobial chemical matter. Addressing these pressing scientific gaps will ensure that we can meet the antibiotic crisis with creativity and purpose. PMID:27622298

  14. Computer Problem-Solving Coaches

    NASA Astrophysics Data System (ADS)

    Hsu, Leon; Heller, Kenneth

    2005-09-01

    Computers might be able to play an important role in physics instruction by coaching students to develop good problem-solving skills. Building on previous research on student problem solving and on designing computer programs to teach cognitive skills, we are developing a prototype computer coach to provide students with guided practice in solving problems. In addition to helping students become better problem solvers, such programs can be useful in studying how students learn to solve problems and how and if problem-solving skills can be transferred from a computer to a pencil-and-paper environment.

  15. Plate removal following orthognathic surgery.

    PubMed

    Little, Mhairi; Langford, Richard Julian; Bhanji, Adam; Farr, David

    2015-11-01

    The objectives of this study are to determine the removal rates of orthognathic plates used during orthognathic surgery at James Cook University Hospital and describe the reasons for plate removal. 202 consecutive orthognathic cases were identified between July 2004 and July 2012. Demographics and procedure details were collected for these patients. Patients from this group who returned to theatre for plate removal between July 2004 and November 2012 were identified and their notes were analysed for data including reason for plate removal, age, smoking status, sex and time to plate removal. 3.2% of plates were removed with proportionally more plates removed from the mandible than the maxilla. 10.4% of patients required removal of one or more plate. Most plates were removed within the first post-operative year. The commonest reasons for plate removal were plate exposure and infection. The plate removal rates in our study are comparable to those seen in the literature.

  16. Less invasive percutaneous wave plating of simple femur shaft fractures: A prospective series.

    PubMed

    Angelini, Alessandro Janson; Livani, Bruno; Flierl, Michael A; Morgan, Steven J; Belangero, William Dias

    2010-06-01

    In developing nations, fixation of femoral shaft fractures with intramedullary (IM) nails can pose significant challenges. Use of IM implants is commonly limited by availability, funds or patient's physique. Conversely, traditional compression plates are usually readily available at a much lower cost, making bridge plating of femur fractures a frequently used surgical technique. We hypothesised that less invasive percutaneous plate osteosynthesis (MIPPO) of femoral shaft fractures has a similar outcome compared to IM nailing. The study is designed as a prospective case series at a Level 1 university trauma centre. Fifty-seven patients with simple femur shaft fractures (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) type A) were enrolled between April 2001 and December 2005 and followed up for a minimum of 1 year or until fracture union. Primary outcome measures included union rate and time to union. Secondary outcome parameters were hardware failure, malalignment, infection and need for revision surgery. The mean age of the study cohort was 24.7 years. Fifty-four patients sustained associated systems injury. Primary union occurred in 54 patients in an average time of 13 weeks. Two patients presented with implant failure, and one patient displayed signs of delayed union. Six patients developed valgus deformities, whereas five patients displayed external rotation malalignment. One patient developed a superficial wound infection, and another presented with a deep infection. Bridge wave plating represents a safe and efficacious treatment alternative to IM nailing for simple femoral shaft fractures in countries where IM nails are limited by availability, costs and patient's physical characteristics. PMID:20170914

  17. Absolute Plate Velocities from Seismic Anisotropy: Importance of Correlated Errors

    NASA Astrophysics Data System (ADS)

    Gordon, R. G.; Zheng, L.; Kreemer, C.

    2014-12-01

    The orientation of seismic anisotropy inferred beneath the interiors of plates may provide a means to estimate the motions of the plate relative to the deeper mantle. Here we analyze a global set of shear-wave splitting data to estimate plate motions and to better understand the dispersion of the data, correlations in the errors, and their relation to plate speed. The errors in plate motion azimuths inferred from shear-wave splitting beneath any one tectonic plate are shown to be correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two-tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining relative plate angular velocities to consistency with the MORVEL relative plate angular velocities. Our preferred set of angular velocities, SKS-MORVEL, is determined from the poles from eight plates weighted proportionally to the root-mean-square velocity of each plate. SKS-MORVEL indicates that eight plates (Amur, Antarctica, Caribbean, Eurasia, Lwandle, Somalia, Sundaland, and Yangtze) have angular velocities that differ insignificantly from zero. The net rotation of the lithosphere is 0.25±0.11º Ma-1 (95% confidence limits) right-handed about 57.1ºS, 68.6ºE. The within-plate dispersion of seismic anisotropy for oceanic lithosphere (σ=19.2°) differs insignificantly from that for continental lithosphere (σ=21.6°). The between-plate dispersion, however, is significantly smaller for oceanic lithosphere (σ=7.4°) than for continental lithosphere (σ=14.7°). Two of the slowest-moving plates, Antarctica (vRMS=4 mm a-1, σ=29°) and Eurasia (vRMS=3 mm a-1, σ=33°), have two of the largest within-plate dispersions, which may indicate that a plate must move faster than ≈5 mm a-1 to result in seismic anisotropy useful for estimating plate motion.

  18. Modal response of a composite plate due to impact

    SciTech Connect

    Zhu, J.; Shah, A.H.; Datta, S.K.

    1995-12-31

    Dynamic response of a fiber reinforced composite plate to an impact load has been studied in this paper. The analysis technique is based on the representation of the elastodynamic field in the plate in terms of guided wave-modes supported by the plate For this purpose, the exact dispersion equation governing the modes has been solved by the Muller`s method, using as starting estimates the wavenumbers that solve the eigenvalue problem obtained by employing a Rayleigh-Ritz type procedure. This avoids the problem of a complicated (and sometimes unreliable) root search needed to solve the transcendental dispersion equations. It is shown that this procedure assures computation of a sufficient number of modes (propagating, nonpropagating, or evanescent) with desirable accuracy. The dynamic field in the plate is then expressed as a sum of the modes. Attention has been focused here on the flexural motion of the plate. Numerical results are presented to show the frequency dependence of the shear stress distribution in the plate.

  19. Surgical Fixation of Sternal Fractures: Preoperative Planning and a Safe Surgical Technique Using Locked Titanium Plates and Depth Limited Drilling

    PubMed Central

    Schulz-Drost, Stefan; Oppel, Pascal; Grupp, Sina; Schmitt, Sonja; Carbon, Roman Th.; Mauerer, Andreas; Hennig, Friedrich F.; Buder, Thomas

    2015-01-01

    Different ways to stabilize a sternal fracture are described in literature. Respecting different mechanisms of trauma such as the direct impact to the anterior chest wall or the flexion-compression injury of the trunk, there is a need to retain each sternal fragment in the correct position while neutralizing shearing forces to the sternum. Anterior sternal plating provides the best stability and is therefore increasingly used in most cases. However, many surgeons are reluctant to perform sternal osteosynthesis due to possible complications such as difficulties in preoperative planning, severe injuries to mediastinal organs, or failure of the performed method. This manuscript describes one possible safe way to stabilize different types of sternal fractures in a step by step guidance for anterior sternal plating using low profile locking titanium plates. Before surgical treatment, a detailed survey of the patient and a three dimensional reconstructed computed tomography is taken out to get detailed information of the fracture’s morphology. The surgical approach is usually a midline incision. Its position can be described by measuring the distance from upper sternal edge to the fracture and its length can be approximated by the summation of 60 mm for the basis incision, the thickness of presternal soft tissue and the greatest distance between the fragments in case of multiple fractures. Performing subperiosteal dissection along the sternum while reducing the fracture, using depth limited drilling, and fixing the plates prevents injuries to mediastinal organs and vessels. Transverse fractures and oblique fractures at the corpus sterni are plated longitudinally, whereas oblique fractures of manubrium, sternocostal separation and any longitudinally fracture needs to be stabilized by a transverse plate from rib to sternum to rib. Usually the high convenience of a patient is seen during follow up as well as a precise reconstruction of the sternal morphology. PMID

  20. Reduction of astrometric plates

    NASA Technical Reports Server (NTRS)

    Stock, J.

    1984-01-01

    A rapid and accurate method for the reduction of comet or asteroid plates is described. Projection equations, scale length correction, rotation of coordinates, linearization, the search for additional reference stars, and the final solution are examined.

  1. Violin plate modes.

    PubMed

    Gough, Colin

    2015-01-01

    As the first step toward developing a generic model for the acoustically radiating vibrational modes of the violin and related instruments, the modes of both freely supported and edge-constrained top and back plates have been investigated as functions of shape, arching height, elastic anisotropy, the f-holes and associated island area, thickness graduations, and the additional boundary constraints of the ribs, soundpost, and bass-bar present in the assembled instrument. Comsol shell structure finite element software has been used as a quasi-experimental tool, with physical and geometric properties varied smoothly, often over several orders of magnitude, allowing the development of the plate modes to be followed continuously from those of an initially square plate to those of doubly-arched, guitar-shaped, orthotropic plates and their dependence on all the above factors. PMID:25618046

  2. Violin plate modes.

    PubMed

    Gough, Colin

    2015-01-01

    As the first step toward developing a generic model for the acoustically radiating vibrational modes of the violin and related instruments, the modes of both freely supported and edge-constrained top and back plates have been investigated as functions of shape, arching height, elastic anisotropy, the f-holes and associated island area, thickness graduations, and the additional boundary constraints of the ribs, soundpost, and bass-bar present in the assembled instrument. Comsol shell structure finite element software has been used as a quasi-experimental tool, with physical and geometric properties varied smoothly, often over several orders of magnitude, allowing the development of the plate modes to be followed continuously from those of an initially square plate to those of doubly-arched, guitar-shaped, orthotropic plates and their dependence on all the above factors.

  3. Flat plate solar oven

    SciTech Connect

    Parikh, M.

    1981-01-01

    The construction of an Indian Rs. 186 (US $20.33) flat-plate solar oven is described. Detailed drawings are provided and relevant information on cooking times and temperature for different foods is given.

  4. Tectonic Plate Movement.

    ERIC Educational Resources Information Center

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  5. Plate tectonics: Metamorphic myth

    NASA Astrophysics Data System (ADS)

    Korenaga, Jun

    2016-01-01

    Clear evidence for subduction-induced metamorphism, and thus the operation of plate tectonics on the ancient Earth has been lacking. Theoretical calculations indicate that we may have been looking for something that cannot exist.

  6. Parallel plate waveguide with anisotropic graphene plates: Effect of electric and magnetic biases

    NASA Astrophysics Data System (ADS)

    Malekabadi, Ali; Charlebois, Serge A.; Deslandes, Dominic

    2013-03-01

    The performances of a parallel plate waveguide (PPWG) supported by perfect electric conductor (PEC)-graphene and graphene-graphene plates are evaluated. The graphene plate behavior is modeled as an anisotropic medium with both diagonal and Hall conductivities derived from Kubo formula. The PPWG modes supported by PEC-graphene and graphene-graphene plates are studied. Maxwell's equations are solved for these two waveguides, while the graphene layers are biased with an electric field only and with both electric and magnetic fields. It is shown that when both electric and magnetic biases are applied to the graphene, a hybrid mode (simultaneous transverse electric (TE) and transverse magnetic (TM) modes) will propagate inside the waveguide. The intensity of each TE and TM modes can be adjusted with the applied external bias fields. Study of different waveguides demonstrates that by decreasing the plate separation (d), the wave confinement improves. However, it increases the waveguide attenuation. A dielectric layer inserted between the plates can also be used to improve the wave confinement. The presented analytical procedure is applicable to other guiding structures having walls with isotropic or anisotropic conductivities.

  7. The postbuckling analysis of laminated circular plate with elliptic delamination

    NASA Astrophysics Data System (ADS)

    Chen, Deliang; Chen, Changping; Fu, Yiming

    2011-01-01

    Based on the Von Karman plate theory, considering the effect of transverse shear deformation, and using the method of the dissociated three regions, the postbuckling governing equations for the axisymmetric laminated circular plates with elliptical delamination are derived. By using the orthogonal point collocation method, the governing equations, boundary conditions and continuity conditions are transformed into a group of nonlinear algebraically equation and the equations are solved with the alternative method. In the numerical examples, the effects of various elliptical in shape, delamination depth and different material properties on buckling and postbuckling of the laminated circular plates are discussed and the numerical results are compared with available data.

  8. Positive battery plate

    NASA Technical Reports Server (NTRS)

    Rowlette, John R. (Inventor)

    1985-01-01

    The power characteristics of a lead acid battery are improved by incorporating a dispersion of 1 to 10% by weight of a thermodynamically stable conductivity additive, such as conductive tin oxide coated glass fibers (34) of filamentary glass wool (42) in the positive active layer (32) carried on the grid (30) of the positive plate (16). Positive plate potential must be kept high enough to prevent reduction of the tin oxide to tin by utilizing an oversized, precharged positive paste.

  9. Fractal multifiber microchannel plates

    NASA Technical Reports Server (NTRS)

    Cook, Lee M.; Feller, W. B.; Kenter, Almus T.; Chappell, Jon H.

    1992-01-01

    The construction and performance of microchannel plates (MCPs) made using fractal tiling mehtods are reviewed. MCPs with 40 mm active areas having near-perfect channel ordering were produced. These plates demonstrated electrical performance characteristics equivalent to conventionally constructed MCPs. These apparently are the first MCPs which have a sufficiently high degree of order to permit single channel addressability. Potential applications for these devices and the prospects for further development are discussed.

  10. [Review of 40 years AO/ASIF. The development of the Veterinary Surgical Working Group for Osteosynthesis Questions(AO) in Veterinary Medicine (AOVET) and a systematic operative fracture treatment in animals].

    PubMed

    Kasa, G; Kasa, F; Kasa, A; Pohler, O

    2011-01-01

    With respect to the founding of the AOVET in 1969, the development of the systematic osteosynthesis in large and small animals is reviewed. With the introduction of the stable OS techniques corresponding to the principles and operative techniques developed by the organization of ASIF/AO (hum), the systematic operative fracture treatment in animals expanded remarkably. The application of the "absolutely" stable compression osteosynthesis was the basis for the successful fracture treatment in large animals. The systematic osteosynthesis in small animals was realized through the generation of a multitude of stabilization techniques for the different fracture types in the various anatomical areas and for special orthopaedic interventions. This was achieved through a specifically developed implant- instrument system and corresponding operation methods. This development was supported by instruction courses, published manuals and visiting fellowships. The extensive collaboration in research and development led to an increasing understanding of the diverse bone healing processes. The AOVET enjoyed a progressing integration into the AO/ASIF (hum) organization. PMID:22134662

  11. Dynamic behaviour of thin composite plates for different boundary conditions

    SciTech Connect

    Sprintu, Iuliana E-mail: rotaruconstantin@yahoo.com; Rotaru, Constantin E-mail: rotaruconstantin@yahoo.com

    2014-12-10

    In the context of composite materials technology, which is increasingly present in industry, this article covers a topic of great interest and theoretical and practical importance. Given the complex design of fiber-reinforced materials and their heterogeneous nature, mathematical modeling of the mechanical response under different external stresses is very difficult to address in the absence of simplifying assumptions. In most structural applications, composite structures can be idealized as beams, plates, or shells. The analysis is reduced from a three-dimensional elasticity problem to a oneor two-dimensional problem, based on certain simplifying assumptions that can be made because the structure is thin. This paper aims to validate a mathematical model illustrating how thin rectangular orthotropic plates respond to the actual load. Thus, from the theory of thin plates, new analytical solutions are proposed corresponding to orthotropic rectangular plates having different boundary conditions. The proposed analytical solutions are considered both for solving equation orthotropic rectangular plates and for modal analysis.

  12. Vibration suppression of composite laminated plate with nonlinear energy sink

    NASA Astrophysics Data System (ADS)

    Zhang, Ye-Wei; Zhang, Hao; Hou, Shuai; Xu, Ke-Fan; Chen, Li-Qun

    2016-06-01

    The composite laminated plate is widely used in supersonic aircraft. So, there are many researches about the vibration suppression of composite laminated plate. In this paper, nonlinear energy sink (NES) as an effective method to suppress vibration is studied. The coupled partial differential governing equations of the composite laminated plate with the nonlinear energy sink (NES) are established by using the Hamilton principle. The fourth-order Galerkin discrete method is used to truncate the partial differential equations, which are solved by numerical integration method. Meanwhile study about the precise effectiveness of the nonlinear energy sink (NES) by discussing the different installation location of the nonlinear energy sink (NES) at the same speed. The results indicate that the nonlinear energy sink (NES) can significantly suppress the severe vibration of the composite laminated plate with speed wind loadings in to protect the composite laminated plate from excessive vibration.

  13. Numerical solution of acoustic scattering by finite perforated elastic plates

    NASA Astrophysics Data System (ADS)

    Cavalieri, A. V. G.; Wolf, W. R.; Jaworski, J. W.

    2016-04-01

    We present a numerical method to compute the acoustic field scattered by finite perforated elastic plates. A boundary element method is developed to solve the Helmholtz equation subjected to boundary conditions related to the plate vibration. These boundary conditions are recast in terms of the vibration modes of the plate and its porosity, which enables a direct solution procedure. A parametric study is performed for a two-dimensional problem whereby a cantilevered perforated elastic plate scatters sound from a point quadrupole near the free edge. Both elasticity and porosity tend to diminish the scattered sound, in agreement with previous work considering semi-infinite plates. Finite elastic plates are shown to reduce acoustic scattering when excited at high Helmholtz numbers k0 based on the plate length. However, at low k0, finite elastic plates produce only modest reductions or, in cases related to structural resonance, an increase to the scattered sound level relative to the rigid case. Porosity, on the other hand, is shown to be more effective in reducing the radiated sound for low k0. The combined beneficial effects of elasticity and porosity are shown to be effective in reducing the scattered sound for a broader range of k0 for perforated elastic plates.

  14. The Potsdam Plate Archive

    NASA Astrophysics Data System (ADS)

    Boehm, P.; Steinmetz, M.; Tsvetkov, M.; Tsvetkova, K.

    2006-08-01

    The Virtual Observatory (VO) project will provide a global network platform to support modern astronomical research with fast and easy access to distributed archives via a unified interface and data model. Our aim is to include the historical photographic plates of the Potsdam observatory into this database in the framework of GAVO, the German contribution to VO. This work is part of the DFG project 436 BUL. The Postdam collection of wide-field plates consists of 11 archives, obtained from 1879 to 1970 (see Catalogue of Wide-Field Plate Archives, version 5.0, March 2005, http://www.skyarchive.org/catalogue.html), with a total amount of about 10000 plates and films stored not only in Potsdam but also in Leiden and Sonneberg. Apart from the long timeline provided for the observed objects, the archives reflect the history and development of the Potsdam observatory and of astronomical photography as well. The first astronomical photographs represent a scientific treasure. They offer the possibility to follow the photometric behavior of astronomical objects for about 120 years. This information is unique, because no more reproducible. Our aim is to digitize the old plates as long as their physical status does still allow it, and continue their systematic incorporation into the already existing Wide-Field Plate Database. These data can be used to search for any kind of long-term brightness variations like new flare stars or rapidly varying stars (Froehlich et al., 2002, A&A 391).

  15. Problem Solving Style, Creative Thinking, and Problem Solving Confidence

    ERIC Educational Resources Information Center

    Houtz, John C.; Selby, Edwin C.

    2009-01-01

    Forty-two undergraduate and graduate students completed VIEW: An Assessment of Problem Solving Style, the non-verbal Torrance Test Thinking Creatively with Pictures, and the Problem Solving Inventory (PSI). VIEW assesses individuals' orientation to change, manner of processing, and ways of deciding, while the Torrance test measures several…

  16. Parent Problem Solving: Analysis of Problem Solving in Parenthood Transition.

    ERIC Educational Resources Information Center

    Alpert, Judith L.; And Others

    The general purpose of this study was to explore the possibility of adapting the Means-Ends Problem-Solving procedure (MEPS) to the investigation of the individual's transition to parenthood. Specific purposes were to determine (1) the internal consistency of the Parent Problem-Solving Scale (PPSS), of its subclasses, and of a combined subscale;…

  17. Caribbean plate interactions

    SciTech Connect

    Ball, M. )

    1993-02-01

    Vector analysis of plate motions, derived from studies of Atlantic magnetic lineations and fracture zone trends, indicates the following relative movements between the Caribbean, North American, and South American Plates. (1) During Early Jurassic to Early Cretaceous, the North American Plate moved 1900 km westward and 900 km northward relative to the South American Plate. A broad zone including the Caribbean region, i.e., the zone between the North and South America Plates, was a site of left-lateral shear and north-south extension. (2) During Early Cretaceous to Late Cretaceous, the North American Mate moved an additional 1200 km westward relative to South America across this zone. (3) During Late Cretaceous to the end of the Eocene, the North American Plate moved 200 km westward and 400 km northward relative to the South American Plate. (4) From the end of the Eocene to near the end of the Miocene, North America converged on South America some 200 km and moved 100 km eastward relative to it. Through the Mesozoic and earliest Tertiary history of the Caribbean, the region was a shear zone within which left-lateral displacement exceeded 3000 km and north-south extension exceeded 1300 km. In regard to time, 80% of the history of the Caribbean region is one of north-south extension and left-lateral shear. In terms of space, 97% of the shear is left-lateral and the ratio of divergence versus convergence is 7 to 1. Thus, characterizing the Caribbean region, and the Atlantic to its east, as a zone of north-south extension and left-lateral shear, is a fair generalization.

  18. Cadmium plating replacements

    NASA Technical Reports Server (NTRS)

    Nelson, Mary J.; Groshart, Earl C.

    1995-01-01

    The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

  19. Simulation of the stationary electrochemical surface treatment by two asymmetric cathode plates

    NASA Astrophysics Data System (ADS)

    Klokov, V. V.; Sergeev, D. E.

    2012-11-01

    The hydrodynamic analogy method was used to solve the problem of stationary electrochemical shaping with two semi-infinite cathode plates arranged arbitrarily relative to the feed direction. A feature of the problem is the multivalence of the velocity hodograph.

  20. Contextual Problem Solving Model Origination

    ERIC Educational Resources Information Center

    Ernst, Jeremy V.

    2009-01-01

    Problem solving has become a central focus of instructional activity in technology education classrooms at all levels (Boser, 1993). Impact assessment considerations incorporating society, culture, and economics are factors that require high-level deliberation involving critical thinking and the implementation of problem solving strategy. The…

  1. Problem Solving, Scaffolding and Learning

    ERIC Educational Resources Information Center

    Lin, Shih-Yin

    2012-01-01

    Helping students to construct robust understanding of physics concepts and develop good solving skills is a central goal in many physics classrooms. This thesis examine students' problem solving abilities from different perspectives and explores strategies to scaffold students' learning. In studies involving analogical problem solving…

  2. Problem Solving in the Professions.

    ERIC Educational Resources Information Center

    Jackling, Noel; And Others

    1990-01-01

    It is proposed that algorithms and heuristics are useful in improving professional problem-solving abilities when contextualized within the academic discipline. A basic algorithm applied to problem solving in undergraduate engineering education and a similar algorithm applicable to legal problems are used as examples. Problem complexity and…

  3. Learning Impasses in Problem Solving

    NASA Technical Reports Server (NTRS)

    Hodgson, J. P. E.

    1992-01-01

    Problem Solving systems customarily use backtracking to deal with obstacles that they encounter in the course of trying to solve a problem. This paper outlines an approach in which the possible obstacles are investigated prior to the search for a solution. This provides a solution strategy that avoids backtracking.

  4. Difficulties in Genetics Problem Solving.

    ERIC Educational Resources Information Center

    Tolman, Richard R.

    1982-01-01

    Examined problem-solving strategies of 30 high school students as they solved genetics problems. Proposes a new sequence of teaching genetics based on results: meiosis, sex chromosomes, sex determination, sex-linked traits, monohybrid and dihybrid crosses (humans), codominance (humans), and Mendel's pea experiments. (JN)

  5. Adolescent Problem-Solving Thinking

    ERIC Educational Resources Information Center

    Platt, Jerome J.; And Others

    1974-01-01

    The hypothesis that adolescent psychiatric patients would be deficient with respect to normal controls in their interpersonal problem-solving skills was tested by comparing the patient and control groups on seven tasks ref lecting different aspects of problem solving. (Author)

  6. Multiple Ways to Solve Proportions

    ERIC Educational Resources Information Center

    Ercole, Leslie K.; Frantz, Marny; Ashline, George

    2011-01-01

    When solving problems involving proportions, students may intuitively draw on strategies that connect to their understanding of fractions, decimals, and percents. These two statements--"Instruction in solving proportions should include methods that have a strong intuitive basis" and "Teachers should begin instruction with more intuitive…

  7. Creative Thinking and Problem Solving.

    ERIC Educational Resources Information Center

    Lacy, Grace

    The booklet considers the nature of creativity in children and examines classroom implications. Among the topics addressed are the following: theories about creativity; research; developments in brain research; the creative process; creative problem solving; the Structure of Intellect Problem Solving (SIPS) model; a rationale for creativity in the…

  8. The Future Problem Solving Program.

    ERIC Educational Resources Information Center

    Crabbe, Anne B.

    1989-01-01

    Describes the Future Problem Solving Program, in which students from the U.S. and around the world are tackling some complex challenges facing society, ranging from acid rain to terrorism. The program uses a creative problem solving process developed for business and industry. A sixth-grade toxic waste cleanup project illustrates the process.…

  9. Schema and Problem-Solving.

    ERIC Educational Resources Information Center

    Callison, Daniel

    1998-01-01

    Presents a revised working definition of schema, lists four types of knowledge that individuals have (i.e., identification, elaboration, planning, and execution), and outlines issues in schema theory. The usefulness of schema in problem solving and information problem solving is discussed, and implications for teachers of information literacy are…

  10. Problem Solving vis Soap Bubbles

    ERIC Educational Resources Information Center

    Bader, William A.

    1975-01-01

    Describes the use of a scientific phenomenon related to the concept of surface tension as an intriguing vehicle to direct attention to useful problem solving techniques. The need for a definite building process in attempts to solve mathematical problems is stressed. (EB)

  11. BEPLATE emdash simulation of electrochemical plating

    SciTech Connect

    Giles, G.E. ); Gray, L.J. ); Bullock, J.S. IV )

    1990-09-01

    BEPLATE is a FORTRAN code that uses the boundary element method to simulate the electrochemical plating of material on parts, primarily rotating axisymmetric parts. A boundary element technique is used to solve for the local current density and thus the plating rate on the part, which is used to calculate the growth in the plated layer over a user-specified time step. The surface is moved to reflect this growth, and the new surface is used to generate the local current density. This cycle is repeated until the final time specified by the analyst, producing the final plated thickness. BEPLATE includes models for the polarization effects at both the part (cathode) and anode and allows the use of symmetry planes and nonconducting shields. For electroplating simulations, the part shape is normally assumed to be axisymmetric with a centerline along the z-axis. More general part shapes can be analyzed by BEPLATE if the surface growth simulation is not needed. In either case, the shield, anode, and tank geometries are not restricted to specific shapes. This report includes the information required to run BEPLATE, specifically, a brief description of the BEPLATE system including hardware and software requirements, a description of the complete simulation process, discussion of rules for generating models, and additional reference material. This system of codes consists of model generators (PIGS or PATRAN), input processor (BEPIN), the simulation code (BEPLATE) and postprocessing codes (PATRAN or CONPLOT).

  12. Bipolar battery plate

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1987-01-01

    A liquid-impermeable plate (10) having through-plate conductivity with essentially zero resistance comprises an insulator sheet (12) having a series of spaced perforations (14) each of which contains a metal element (16) sealingly received into the perforation (14). A low-cost plate can readily be manufactured by punching a thermoplastic sheet (40) such as polypropylene with a punching tool (52), filling the apertures with led spheres (63) having a diameter smaller than the holes (50) but larger than the thickness of the sheet, sweeping excess spheres (62) off the sheet with a doctor blade (60) and then pressing a heated platen (74) onto the sheet to swage the spheres into a cylindrical shape and melt the surrounding resin to form a liquid-impermeable collar (4) sealing the metal into the sheet.

  13. Disturbed film flow on a vertical plate

    NASA Astrophysics Data System (ADS)

    Kheshgi, Haroon S.; Scriven, L. E.

    1987-04-01

    Flow of incompressible Newtonian liquid films is governed by the Navier-Stokes system with shear-free, balanced-normal-stress, and kinematic boundary conditions at the free surface. This system is solved here for the evolution of finite-amplitude two-dimensional disturbances to otherwise steady flow down a vertical plate by means of a finite element method adapted for free boundary problems. When flow is specified to be spatially periodic, fully developed steady flows that ensue approach time-periodic states, i.e., waves, the finite amplitude of which depends upon their wavelength. The family of time-periodic states connects to the steady, fully developed flow at a Hopf bifurcation that lies at a critical disturbance length, in agreement with the Orr-Sommerfeld analysis. Initial disturbances to flow down a plate of finite length grow as they propagate downward. In all cases studied here, however, steady flow is eventually approached.

  14. Plate-mantle coupling from post-Pangea plate kinematics

    NASA Astrophysics Data System (ADS)

    Zahirovic, Sabin; Dietmar Müller, R.; Seton, Maria; Flament, Nicolas

    2015-04-01

    Convection in the Earth's mantle that involves plates at the surfaces gives rise to plate velocities that vary through time and depend on the balance of plate boundary forces, with the present-day providing a snapshot of this ongoing process. However, present-day plate velocities do not capture plate behaviour over geologically representative timeframes and thus cannot be used to evaluate factors limiting plate velocities. Previous studies investigated the effects of continental keels on plate speeds by either using the present-day snapshot or a limited number of reconstructed plate configurations, often leading to conflicting results. For example, an early assumption was that continental keels (especially cratons) were unlikely to impede fast plate motions because India's velocity approached ~20 cm/yr in the Eocene prior to the collision with Eurasia. We employ a modern plate reconstruction approach with evolving global topological plate boundaries for the post-Pangea timeframe (since 200 Ma) to evaluate factors controlling plate velocities. Plate boundary configurations and plate velocities are extracted from the open-source and cross-platform plate reconstruction package GPlates (www.gplates.org) at 1 Myr intervals. For each plate, at each timestep, the area of continental and cratonic lithosphere is calculated to evaluate the effect on plate velocities. Our results support that oceanic plates tend to be 2-3 times faster than plates with large portion of continental plate area, consistent with predictions of numerical models of mantle convection. The fastest plates (~8.5 cm/yr RMS) are dominated by oceanic plate area and high subducting portion of plate perimeter, while the slowest plates (~2.6-2.8 cm/yr RMS) are dominated by continental plate area and bounded by transforms and mid-oceanic ridge segments. Importantly, increasing cratonic fractions (both Proterozoic and Archean lithosphere) significantly impede plate velocities, suggesting that deep continental

  15. Pulsating Star Mystery Solved

    NASA Astrophysics Data System (ADS)

    2010-11-01

    By discovering the first double star where a pulsating Cepheid variable and another star pass in front of one another, an international team of astronomers has solved a decades-old mystery. The rare alignment of the orbits of the two stars in the double star system has allowed a measurement of the Cepheid mass with unprecedented accuracy. Up to now astronomers had two incompatible theoretical predictions of Cepheid masses. The new result shows that the prediction from stellar pulsation theory is spot on, while the prediction from stellar evolution theory is at odds with the new observations. The new results, from a team led by Grzegorz Pietrzyński (Universidad de Concepción, Chile, Obserwatorium Astronomiczne Uniwersytetu Warszawskiego, Poland), appear in the 25 November 2010 edition of the journal Nature. Grzegorz Pietrzyński introduces this remarkable result: "By using the HARPS instrument on the 3.6-metre telescope at ESO's La Silla Observatory in Chile, along with other telescopes, we have measured the mass of a Cepheid with an accuracy far greater than any earlier estimates. This new result allows us to immediately see which of the two competing theories predicting the masses of Cepheids is correct." Classical Cepheid Variables, usually called just Cepheids, are unstable stars that are larger and much brighter than the Sun [1]. They expand and contract in a regular way, taking anything from a few days to months to complete the cycle. The time taken to brighten and grow fainter again is longer for stars that are more luminous and shorter for the dimmer ones. This remarkably precise relationship makes the study of Cepheids one of the most effective ways to measure the distances to nearby galaxies and from there to map out the scale of the whole Universe [2]. Unfortunately, despite their importance, Cepheids are not fully understood. Predictions of their masses derived from the theory of pulsating stars are 20-30% less than predictions from the theory of the

  16. NICKEL PLATING PROCESS

    DOEpatents

    Hoover, T.B.; Zava, T.E.

    1959-05-12

    A simplified process is presented for plating nickel by the vapor decomposition of nickel carbonyl. In a preferred form of the invention a solid surface is nickel plated by subjecting the surface to contact with a mixture containing by volume approximately 20% nickel carbonyl vapor, 2% hydrogen sulfide and .l% water vapor or 1% oxygen and the remainder carbon dioxide at room temperature until the desired thickness of nickel is obtained. The advantage of this composition over others is that the normally explosive nickel carbonyl is greatly stabilized.

  17. Reduced Plating Ignitron

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A (Inventor); Pearson, J Boise (Inventor)

    2014-01-01

    An ignitron apparatus has an airtight tubular housing having a first sealed end and a second sealed end. An anode is connected at the first sealed end, projecting into the housing, and a recess at the second sealed and forms a well which contains a quantity of liquid gallium or gallium alloy making up the cathode. An ignitor projects through the liquid metal and into the housing. The inner surface of the housing includes at least one plating-reduction structure to prevent electrical shorting of the apparatus caused by plating of the liquid metal.

  18. Wave propagation of functionally graded material plates in thermal environments.

    PubMed

    Sun, Dan; Luo, Song-Nan

    2011-12-01

    The wave propagation of an infinite functionally graded plate in thermal environments is studied using the higher-order shear deformation plate theory. The thermal effects and temperature-dependent material properties are both taken into account. The temperature field considered is assumed to be a uniform distribution over the plate surface and varied in the thickness direction only. Material properties are assumed to be temperature-dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Considering the effects of transverse shear deformation and rotary inertia, the governing equations of the wave propagation in the functionally graded plate are derived by using the Hamilton's principle. The analytic dispersion relation of the functionally graded plate is obtained by solving an eigenvalue problem. Numerical examples show that the characteristics of wave propagation in the functionally graded plate are relates to the volume fraction index and thermal environment of the functionally graded plate. The influences of the volume fraction distributions and temperature on wave propagation of functionally graded plate are discussed in detail. The results carried out can be used in the ultrasonic inspection techniques and structural health monitoring.

  19. Intermittent Plate Tectonics

    NASA Astrophysics Data System (ADS)

    Silver, P. G.; Behn, M. D.

    2006-12-01

    Intermittent Plate Tectonics A basic premise of Earth Science is that plate tectonics has been continuously operating since it began early in Earth's history. Yet, plate-tectonic theory itself, specifically the collisional phase of the Wilson Cycle, constitutes a process that is capable of stopping all plate motion. The plausibility of a plate-tectonic hiatus is most easily illustrated by considering the expected future of the present-day plate-tectonic configuration. Since the opening of the Atlantic at ~200 ma, the area of the Atlantic basin has been growing at the expense of the Pacific. If this trend continues, relative plate motion models predict that in ~350 my, the Pacific Ocean basin will effectively close leading to widespread continent-continent collisions. Since a continent-continent collision represents the termination of subduction locally, the accumulated effect of all collisions is to stop subduction globally. In this scenario, ridges would then stop spreading and young oceanic lithosphere would cool, reaching a steady-state thickness of 100 km in about 80 my, based on the properties of oceanic lithosphere today. This would constitute the stoppage of plate tectonics. The presumption that plate tectonics never stops in the face of continental collisions is equivalent to requiring that subduction flux is approximately constant through time, such that subduction initiation roughly balances subduction termination. Such a balance then raises several questions about the subduction initiation process. When and how does subduction initiate? Is there a detectible relationship between subduction cessation and subduction initiation? We can gain some guidance into these questions by examining the plate motion history over the last 200 my. Subduction initiation has occurred over the last 80 my in three intra- oceanic subduction zones: Aleutians, Marianas-Izu-Bonin and Tonga-Kermadec in the Pacific basin. In these cases, however, subduction initiation would not

  20. Vibration Analysis of Annular Plates with Concentric Supports Using a Variant of Rayleigh-Ritz Method

    NASA Astrophysics Data System (ADS)

    Wang, C. M.; Thevendran, V.

    1993-05-01

    A variant of the Rayleigh-Ritz method is presented for solving the free vibration problem of annular plates with internal axisymmetric supports. The method is simple, accurate and may be readily programmed and run on a microcomputer. A comprehensive tabulation of the fundamental frequencies is presented for isotropic annular plates with an internal concentric support. Results for full circular plates with concentric supports are also obtained by making the inner radial edge free and permitting the inner radius to become very small.

  1. On the analysis of a plate with a local shape perturbation

    NASA Astrophysics Data System (ADS)

    Kolpakov, A. G.

    2012-07-01

    The asymptotic behavior of the solution of the bending problem of plates with local shape perturbations (connections, ribs, holes comparable in size with the plate thickness) is studied in a three-dimensional formulation using the local perturbation method. The problem is completely decomposed into a two-dimensional problem of plate theory and local problems describing the threedimensional stress-strain state in the perturbation region. The local problems are solved using numerical methods.

  2. Salvage of failed osteosynthesis of an intracapsular fracture of the femoral neck using two cannulated compression screws and a vascularised iliac crest bone graft.

    PubMed

    Xiaobing, Y; Dewei, Z

    2015-07-01

    We evaluated the outcome of treatment of nonunion of an intracapsular fracture of the femoral neck in young patients using two cannulated screws and a vascularised bone graft. A total of 32 patients (15 women and 17 men, with a mean age of 36.5 years; 20 to 50) with failed internal fixation of an intracapsular fracture were included in the study. Following removal of the primary fixation, two cannulated compression screws were inserted with a vascularised iliac crest bone graft based on the ascending branch of the lateral femoral circumflex artery. At a mean follow-up of 6.8 years (4 to 10), union was achieved in 27 hips (84%). A total of five patients with a mean age of 40.5 years (35 to 50) had a persistent nonunion and underwent total hip arthroplasty as also did two patients whose fracture united but who developed osteonecrosis of the femoral head two years post-operatively. Statistical analysis showed that younger patients achieved earlier and more reliable union (p < 0.001). The functional outcome, as assessed by the Harris Hip score, was better in patients aged < 45 years compared with those aged > 45 years (p < 0.001). These findings suggest that further fixation using two cannulated compression screws and a vascularised iliac crest bone graft is an effective salvage treatment in patients aged < 45 years, in whom osteosynthesis of a displaced intracapsular fractures of the femoral neck has failed.

  3. Nuclear reactor alignment plate configuration

    DOEpatents

    Altman, David A; Forsyth, David R; Smith, Richard E; Singleton, Norman R

    2014-01-28

    An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accomodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through with the dowel pins pass.

  4. Unitary plate electrode

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor); Clough, Thomas J. (Inventor); Josefowicz, Jack Y. (Inventor); Sibert, John W. (Inventor)

    1985-01-01

    The unitary electrode (10) comprises a porous sheet (12) of fiberglass the strands (14) of which contain a coating (16) of conductive tin oxide. The lower portion of the sheet contains a layer (18) of resin and the upper layer (20) contains lead dioxide forming a positive active electrode on an electrolyte-impervious layer. The strands (14) form a continuous conduction path through both layers (16, 18). Tin oxide is prevented from reduction by coating the surface of the plate facing the negative electrode with a conductive, impervious layer resistant to reduction such as a thin film (130) of lead or graphite filled resin adhered to the plate with a layer (31) of conductive adhesive. The plate (10) can be formed by casting a molten resin from kettle (60) onto a sheet of glass wool (56) overlying a sheet of lead foil and then applying positive active paste from hopper (64) into the upper layer (68). The plate can also be formed by passing an assembly of a sheet ( 80) of resin, a sheet (86) of sintered glass and a sheet (90) of lead between the nip (92) of heated rollers (93, 95) and then filling lead oxide into the pores (116) of the upper layer (118).

  5. The Plate Tectonics Project

    ERIC Educational Resources Information Center

    Hein, Annamae J.

    2011-01-01

    The Plate Tectonics Project is a multiday, inquiry-based unit that facilitates students as self-motivated learners. Reliable Web sites are offered to assist with lessons, and a summative rubric is used to facilitate the holistic nature of the project. After each topic (parts of the Earth, continental drift, etc.) is covered, the students will…

  6. INL HIP Plate Fabrication

    SciTech Connect

    B. H. Park; C. R. Clark; J. F. Jue

    2010-02-01

    This document outlines the process used to bond monolithic fuel plates by Hot Isostatic Pressing (HIP). This method was developed at Idaho National Laboratory (INL) for the Reduced Enrichment for Research and Test Reactors (RERTR) program. These foils have been used in a number of irradiation experiments in support of the United States Global Threat Reduction Initiative (GTRI) program.

  7. Growth Plate Injuries

    MedlinePlus

    ... or crushed, the growth plate may close prematurely, forming a bony bridge or “bar.” The risk of ... this publication: James S. Panagis, M.D., M.P.H., NIAMS/NIH; R. Tracy Ballock, M.D., Case ...

  8. Minimally Invasive Medial Plating of Low-Energy Lisfranc Injuries: Preliminary Experience with Five Cases

    PubMed Central

    del Vecchio, Jorge Javier; Ghioldi, Mauricio; Raimondi, Nicolás; De Elias, Manuel

    2016-01-01

    Fracture dislocations involving the Lisfranc joint are rare; they represent only 0.2% of all the fractures. There is no consensus about the surgical management of these lesions in the medical literature. However, both anatomical reduction and tarsometatarsal stabilization are essential for a good outcome. In this clinical study, five consecutive patients with a diagnosis of Lisfranc low-energy lesion were treated with a novel surgical technique characterized by minimal osteosynthesis performed through a minimally invasive approach. According to the radiological criteria established, the joint reduction was anatomical in four patients, almost anatomical in one patient (#4), and nonanatomical in none of the patients. At the final follow-up, the AOFAS score for the midfoot was 96 points (range, 95–100). The mean score according to the VAS (Visual Analog Scale) at the end of the follow-up period was 1.4 points over 10 (range, 0–3). The surgical technique described in this clinical study is characterized by the use of implants with the utilization of a novel approach to reduce joint and soft tissue damage. We performed a closed reduction and minimally invasive stabilization with a bridge plate and a screw after achieving a closed anatomical reduction. PMID:27340569

  9. Endovascular treatment of anterior tibial artery pseudoaneurysm following locking compression plating of the tibia.

    PubMed

    van Hensbroek, P Boele; Ponsen, K J; Reekers, J A; Goslings, J C

    2007-04-01

    Less invasive surgery and interventional radiology are relatively new techniques. This case report describes a patient with a distal tibial fracture that was stabilized using minimally invasive osteosynthesis consisting of a precontoured metaphyseal Locking Compression Plate (LCP). Postoperative radiographs showed good alignment of the bone, and the initial postoperative course was uneventful. At the sixth-week follow-up visit after surgery, the patient presented with a pulsating and tender mass on the lower leg that was palpable subcutaneously. Arteriography showed a pseudoaneurysm of the anterior tibial artery. At the same procedure an endovascular stent was placed, thereby excluding the pseudoaneurysm from the main circulation while keeping the vessel lumen patent. At the time of the last visit, 6 months after the operation, the patient was fully weightbearing with normal function of the ankle but with a nonhealing fracture on the x-ray. The dorsalis pedis pulse was equally strong as on the right side. Endovascular treatment with a covered stent proved to be an effective treatment for the described posttraumatic pseudoaneurysm of the anterior tibial artery. This case illustrates a risk of less invasive fracture surgery and at the same time underlines the value of a multidisciplinary approach to complications in trauma surgery. PMID:17414557

  10. Injury to the anterior tibial system during percutaneous plating of a proximal tibial fracture.

    PubMed

    Gary, Joshua L; Sciadini, Marcus F

    2012-07-01

    Minimally invasive osteosynthesis of proximal tibial fractures has grown in popularity in recent years. This article describes a patient with a Schatzker type VI proximal tibial fracture (AO/OTA type 41.C3) and previous compartment syndrome treated with definitive fixation 8 weeks after initial injury with a precontoured proximal tibial plate and a distal targeting device. Brisk bleeding occurred during percutaneous insertion of a cortical screw at the midshaft of the tibia. Surgical exploration revealed sidewall tearing of the anterior tibial artery and vein, which were clipped at the screw insertion site. After the bleeding was controlled, the patient had a strong palpable posterior tibial pulse with no palpable dorsalis pedis pulse, and the foot remained well perfused. Function of the deep peroneal nerve was normal postoperatively. Previous concerns regarding the percutaneous treatment of proximal tibial fractures have focused on the risks of damage to the superficial peroneal nerve from distal screws. Based on cadaveric studies, percutaneously and laterally based screw placement in the distal tibial metaphysis threatens injury to the anterior tibial system. However, with alterations to the normal anatomy caused by severe trauma, previously described safe zones may be changed and neurovascular structures may be exposed to risk in locations that were previously thought safe. PMID:22784915

  11. Problem Solving with General Semantics.

    ERIC Educational Resources Information Center

    Hewson, David

    1996-01-01

    Discusses how to use general semantics formulations to improve problem solving at home or at work--methods come from the areas of artificial intelligence/computer science, engineering, operations research, and psychology. (PA)

  12. Solving Differential Equations in R

    NASA Astrophysics Data System (ADS)

    Soetaert, Karline; Meysman, Filip; Petzoldt, Thomas

    2010-09-01

    The open-source software R has become one of the most widely used systems for statistical data analysis and for making graphs, but it is also well suited for other disciplines in scientific computing. One of the fields where considerable progress has been made is the solution of differential equations. Here we first give an overview of the types of differential equations that R can solve, and then demonstrate how to use R for solving a 2-Dimensional partial differential equation.

  13. Managing Vancouver B1 fractures by cerclage system compared to locking plate fixation - a biomechanical study.

    PubMed

    Gordon, Katharina; Winkler, Martin; Hofstädter, Thomas; Dorn, Ulrich; Augat, Peter

    2016-06-01

    With increasing life expectancy and number of total hip arthroplasties (THA), the need for revision surgery is increasing too. The aim of this study was to evaluate the optimal fracture treatment for a clinically characteristic Vancouver B1 fracture. We hypothesized that locking plate fixation has biomechanical advantages over fixation with a simple cerclage system. Additionally, we hypothesized that removal of the primary short stem and revision with a long stem would show biomechanical benefit. The biomechanical testing was performed with a static and a dynamic loading protocol on twenty 4th Generation sawbones. These were divided into four different groups (n = 5 each). In group 1, the primary uncemented short stem remained and the fracture was stabilized with a locking plate. In group 2, the primary stem remained and the fracture was stabilized with a cerclage stabilization system containing two stabilizers and four cerclages. In group 3, the primary stem was replaced by an uncemented long revision stem and the fracture was fixed with a locking plate. In group 4, the short stem was replaced by a long revision stem and the fracture was fixed with the cerclage system. Static testing revealed that the revision of the short stem with the long stem caused a 2-fold (p < 0.001, ANOVA) increase of axial stiffness. In dynamic testing, the number of cycles to failure was 4 times (p < 0.001, ANOVA) higher with the long revision stem. Compared to locked plating cerclage wiring demonstrated a 26% more cycles to failure (p = 0.031, ANOVA). The load to failure was 91% larger (p < 0.001, ANOVA) with the long revision stem and 11% smaller with locked plating (p < 0.001, ANOVA). In conclusion, the present biomechanical study indicates that periprosthetic Vancouver B1 fractures can be sufficiently fixed by simple cerclage systems. Revision with a long replacement stem provides a superior mechanical stability regardless of type of osteosynthesis fixation and is therefore a viable

  14. Buckling of Fiber Reinforced Composite Plates with Nanofiber Reinforced Matrices

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.; Murthy, Pappu L. N.

    2010-01-01

    Anisotropic composite plates were evaluated with nanofiber reinforced matrices (NFRM). The nanofiber reinforcement volumes ratio in the matrix was 0.01. The plate dimensions were 20 by 10 by 1.0 in. (508 by 254 by 25.4 mm). Seven different loading condition cases were evaluated: three for uniaxial loading, three for pairs of combined loading, and one with three combined loadings. The anisotropy arose from the unidirectional plates having been at 30 from the structural axis. The anisotropy had a full 6 by 6 rigidities matrix which were satisfied and solved by a Galerkin buckling algorithm. The buckling results showed that the NFRM plates buckled at about twice those with conventional matrix.

  15. Stress analysis of multilayered plates around circular holes

    NASA Technical Reports Server (NTRS)

    Delale, F.

    1984-01-01

    The elasticity problem for a thick plate consisting of two bonded dissimilar homogeneous layers is considered. It is assumed that the plate is infinite, contains a circular hole, and is subjected to axisymmetric external loads. A technique suitable to the formulation of three-dimensional boundary value problems is introduced and applied to the three-dimensional elasticity solution of an infinite plate with a hole. The effect of Poisson's ratio is studied in some detail, and the axisymmetric problem of a laminated plate is solved. The stresses at the interface are calculated and are observed to become unbounded at the hole boundary. An approximate treatment of the singularity is presented and the stress intensity factors are computed. Some of the results are compared with those found from the finite element method. The agreement between the two sets with regard to trend and magnitude is found to be very satisfactory.

  16. Tangram solved? Prefrontal cortex activation analysis during geometric problem solving.

    PubMed

    Ayaz, Hasan; Shewokis, Patricia A; Izzetoğlu, Meltem; Çakır, Murat P; Onaral, Banu

    2012-01-01

    Recent neuroimaging studies have implicated prefrontal and parietal cortices for mathematical problem solving. Mental arithmetic tasks have been used extensively to study neural correlates of mathematical reasoning. In the present study we used geometric problem sets (tangram tasks) that require executive planning and visuospatial reasoning without any linguistic representation interference. We used portable optical brain imaging (functional near infrared spectroscopy--fNIR) to monitor hemodynamic changes within anterior prefrontal cortex during tangram tasks. Twelve healthy subjects were asked to solve a series of computerized tangram puzzles and control tasks that required same geometric shape manipulation without problem solving. Total hemoglobin (HbT) concentration changes indicated a significant increase during tangram problem solving in the right hemisphere. Moreover, HbT changes during failed trials (when no solution found) were significantly higher compared to successful trials. These preliminary results suggest that fNIR can be used to assess cortical activation changes induced by geometric problem solving. Since fNIR is safe, wearable and can be used in ecologically valid environments such as classrooms, this neuroimaging tool may help to improve and optimize learning in educational settings. PMID:23366983

  17. MyPlate Food Guide

    MedlinePlus

    ... follow throughout your life. 2. Fruits Like veggies, fruits contain vitamins, minerals, and fiber. The red section of MyPlate is slightly smaller than the green, but together fruits and veggies should fill half your plate. Whole ...

  18. What Are Growth Plate Injuries?

    MedlinePlus

    ... activities. Other reasons for growth plate injuries are:  Child abuse  Injury from extreme cold (for example, frostbite)  Radiation ( ... problems) treats most growth plate injuries. At other times, the child will see a pediatric orthopaedic surgeon (a doctor ...

  19. What Are Growth Plate Injuries?

    MedlinePlus

    ... activities. Other reasons for growth plate injuries are: Child abuse Injury from extreme cold (for example, frostbite) Radiation ( ... problems) treats most growth plate injuries. At other times, the child will see a pediatric orthopaedic surgeon (a doctor ...

  20. North American plate dynamics

    NASA Technical Reports Server (NTRS)

    Richardson, Randall M.; Reding, Lynn M.

    1991-01-01

    Deformation within the North American plate in response to various tectonic processes is modeled using an elastic finite element analysis. The tectonic processes considered in the modeling include ridge forces associated with the normal thermal evolution of oceanic lithosphere, shear and normal stresses transmitted across transforms, normal stresses transmitted across convergent boundaries, stresses due to horizontal density contrasts within the continent, and shear tractions applied along the base of the plate. Model stresses are calculated with respect to a lithostatic reference stress state. Shear stresses transmitted across transform boundaries along the San Andreas and Caribbean are small, of the order of 5-10 MPa. Also, compressive stresses of the order of 5-10 MPa transmitted across the major transforms improve the fit to the data. Compressive stresses across convergent margins along the Aleutians and the Middle America trench are important.

  1. Microchannel plate streak camera

    DOEpatents

    Wang, Ching L.

    1989-01-01

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays.

  2. Microchannel plate streak camera

    DOEpatents

    Wang, C.L.

    1984-09-28

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (uv to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 keV x-rays.

  3. Microchannel plate streak camera

    DOEpatents

    Wang, C.L.

    1989-03-21

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras is disclosed. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1,000 KeV x-rays. 3 figs.

  4. Bipolar battery plate

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1985-01-01

    A liquid-impermeable plate (10) having throughplate conductivity with essentially zero resistance comprises an insulator sheet (12) having a series of spaced perforations (14) each of which contains a metal element (16) sealingly received into the perforation (14). A low-cost plate can readily be manufactured by punching a thermoplastic sheet (40) such as polypropylene with a punching tool (52), filling the apertures with lead spheres (63) having a diameter smaller than the holes (50) but larger than the thickness of the sheet, sweeping excess spheres (62) off the sheet with a doctor blade (60) and then pressing a heated platen (74) onto the sheet to swage the spheres into a cylindrical shape and melt the surrounding resin to form a liquid-impermeable collar (4) sealing the metal into the sheet.

  5. Finite element study of plate buckling induced by spatial temperature gradients

    SciTech Connect

    Thornton, E.A.; Kolenski, J.D.; Marino, R.P.

    1993-01-01

    Finite element analyses of thermal buckling of thin metallic plates with prescribed spatial temperature distributions are described. Thermally induced compressive membrane stresses and transverse plate displacement imperfections initiate plates buckling. A finite element formulation based on von Karman plate theory is presented. The resulting nonlinear equations are solved for incremental temperature increases by Newton-Raphson iteration. The computational method is used to investigate the buckling response of rectangular plates with steady and unsteady spatially varying temperature distributions. The role of initial plate imperfections and temperature distributions on the nonlinear response of plate displacements and stresses is described. The relatively high levels of stress induced by spatial temperature gradients should be considered carefully in the postbuckling design of panels for aerospace vehicles subjected to combined mechanical and thermal loads. 31 refs.

  6. Acoustic radiation from a laminated composite plate reinforced by doubly periodic parallel stiffeners

    NASA Astrophysics Data System (ADS)

    Yin, X. W.; Gu, X. J.; Cui, H. F.; Shen, R. Y.

    2007-10-01

    Acoustic radiation from a point-driven, infinite fluid-loaded, laminated composite plate which is reinforced by doubly periodic parallel stiffeners is investigated theoretically. The stiffeners interact with the plate only through normal forces. Fourier transform is used for solving the responses of the plate, and the stationary phase approximate is then employed to find an expression for the far field pressure. Acoustic radiation from a stiffened uniform plate composed of multiple isotropic layers is calculated with the present stiffened, laminated composite plate theory, and with the stiffened uniform isotropic plate theory that Mace has proposed. Comparison of the numerical results reveals the validity of our work. Characteristics of the acoustic radiation from a stiffened laminated composite plate are examined through examples and some physical interpretations of significant features are also offered.

  7. Dynamics of Shells and Fluid-Loaded Plates.

    NASA Astrophysics Data System (ADS)

    Wang, Zhang

    This thesis is composed of two parts. The first part is concerned with wave propagation on elastic structures in vacuum. An asymptotic approximation is obtained for the dispersion relation of flexural waves propagating in an infinite, flat plate, with material and/or geometric properties periodic in one direction. A matrix approach is proposed to investigate waves in circular cylindrical thin shells joined with circular plates. Both the general propagator matrix and S-matrix formalisms are presented, with emphasis on the latter. The second part is devoted to structures with ambient fluid loading. The Green's function for a fluid-loaded plate under line loading is expressed as a sum of five fluid-loaded plate waves and an acoustic wave with magnitude given by an infinite integral, similar to a branch cut integral. A scattering matrix approach is presented to solve wave propagation problems on fluid-loaded plates with attached ribs. The low frequency asymptotic dispersion relation for a fluid-loaded plate with infinite number of equally spaced identical ribs is derived, from which an equation of motion for the plate is inferred which is valid also at low frequencies.

  8. Plated wire memory subsystem

    NASA Technical Reports Server (NTRS)

    Reynolds, L.; Tweed, H.

    1972-01-01

    The work performed entailed the design, development, construction and testing of a 4000 word by 18 bit random access, NDRO plated wire memory for use in conjunction with a spacecraft imput/output unit and central processing unit. The primary design parameters, in order of importance, were high reliability, low power, volume and weight. A single memory unit, referred to as a qualification model, was delivered.

  9. Plate motion and deformation

    SciTech Connect

    Minster, B.; Prescott, W.; Royden, L.

    1991-02-01

    Our goal is to understand the motions of the plates, the deformation along their boundaries and within their interiors, and the processes that control these tectonic phenomena. In the broadest terms, we must strive to understand the relationships of regional and local deformation to flow in the upper mantle and the rheological, thermal and density structure of the lithosphere. The essential data sets which we require to reach our goal consist of maps of current strain rates at the earth's surface and the distribution of integrated deformation through time as recorded in the geologic record. Our success will depend on the effective synthesis of crustal kinematics with a variety of other geological and geophysical data, within a quantitative theoretical framework describing processes in the earth's interior. Only in this way can we relate the snapshot of current motions and earth structure provided by geodetic and geophysical data with long-term processes operating on the time scales relevant to most geological processes. The wide-spread use of space-based techniques, coupled with traditional geological and geophysical data, promises a revolution in our understanding of the kinematics and dynamics of plate motions over a broad range of spatial and temporal scales and in a variety of geologic settings. The space-based techniques that best address problems in plate motion and deformation are precise space-geodetic positioning -- on land and on the seafloor -- and satellite acquisition of detailed altimetric and remote sensing data in oceanic and continental areas. The overall science objectives for the NASA Solid Earth Science plan for the 1990's, are to Understand the motion and deformation of the lithosphere within and across plate boundaries'', and to understand the dynamics of the mantle, the structure and evolution of the lithosphere, and the landforms that result from local and regional deformation. 57 refs., 7 figs., 2 tabs.

  10. Martian plate tectonics

    NASA Astrophysics Data System (ADS)

    Sleep, N. H.

    1994-03-01

    The northern lowlands of Mars have been produced by plate tectonics. Preexisting old thick highland crust was subducted, while seafloor spreading produced thin lowland crust during late Noachian and Early Hesperian time. In the preferred reconstruction, a breakup margin extended north of Cimmeria Terra between Daedalia Planum and Isidis Planitia where the highland-lowland transition is relatively simple. South dipping subduction occured beneath Arabia Terra and east dipping subduction beneath Tharsis Montes and Tempe Terra. Lineations associated with Gordii Dorsum are attributed to ridge-parallel structures, while Phelegra Montes and Scandia Colles are interpreted as transfer-parallel structures or ridge-fault-fault triple junction tracks. Other than for these few features, there is little topographic roughness in the lowlands. Seafloor spreading, if it occurred, must have been relatively rapid. Quantitative estimates of spreading rate are obtained by considering the physics of seafloor spreading in the lower (approx. 0.4 g) gravity of Mars, the absence of vertical scarps from age differences across fracture zones, and the smooth axial topography. Crustal thickness at a given potential temperature in the mantle source region scales inversely with gravity. Thus, the velocity of the rough-smooth transition for axial topography also scales inversely with gravity. Plate reorganizations where young crust becomes difficult to subduct are another constraint on spreading age. Plate tectonics, if it occurred, dominated the thermal and stress history of the planet. A geochemical implication is that the lower gravity of Mars allows deeper hydrothermal circulation through cracks and hence more hydration of oceanic crust so that more water is easily subducted than on the Earth. Age and structural relationships from photogeology as well as median wavelength gravity anomalies across the now dead breakup and subduction margins are the data most likely to test and modify hypotheses

  11. Plates with Incompatible Prestrain

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Kaushik; Lewicka, Marta; Schäffner, Mathias

    2016-07-01

    We study effective elastic behavior of the incompatibly prestrained thin plates, where the prestrain is independent of thickness and uniform through the plate's thickness h. We model such plates as three-dimensional elastic bodies with a prescribed pointwise stress-free state characterized by a Riemannian metric G, and seek the limiting behavior as {h to 0}. We first establish that when the energy per volume scales as the second power of h, the resulting {Γ} -limit is a Kirchhoff-type bending theory. We then show the somewhat surprising result that there exist non-immersible metrics G for whom the infimum energy (per volume) scales smaller than h 2. This implies that the minimizing sequence of deformations carries nontrivial residual three-dimensional energy but it has zero bending energy as seen from the limit Kirchhoff theory perspective. Another implication is that other asymptotic scenarios are valid in appropriate smaller scaling regimes of energy. We characterize the metrics G with the above property, showing that the zero bending energy in the Kirchhoff limit occurs if and only if the Riemann curvatures R 1213, R 1223 and R 1212 of G vanish identically. We illustrate our findings with examples; of particular interest is an example where {G_{2 × 2}}, the two-dimensional restriction of G, is flat but the plate still exhibits the energy scaling of the Föppl-von Kármán type. Finally, we apply these results to a model of nematic glass, including a characterization of the condition when the metric is immersible, for {G = Id3 + γ n ⊗ n} given in terms of the inhomogeneous unit director field distribution { n in R^3}.

  12. The Photodynamic Bone Stabilization System: a minimally invasive, percutaneous intramedullary polymeric osteosynthesis for simple and complex long bone fractures

    PubMed Central

    Vegt, Paul; Muir, Jeffrey M; Block, Jon E

    2014-01-01

    The treatment of osteoporotic long bone fractures is difficult due to diminished bone density and compromised biomechanical integrity. The majority of osteoporotic long bone fractures occur in the metaphyseal region, which poses additional problems for surgical repair due to increased intramedullary volume. Treatment with internal fixation using intramedullary nails or plating is associated with poor clinical outcomes in this patient population. Subsequent fractures and complications such as screw pull-out necessitate additional interventions, prolonging recovery and increasing health care costs. The Photodynamic Bone Stabilization System (PBSS) is a minimally invasive surgical technique that allows clinicians to repair bone fractures using a light-curable polymer contained within an inflatable balloon catheter, offering a new treatment option for osteoporotic long bone fractures. The unique polymer compound and catheter application provides a customizable solution for long bone fractures that produces internal stability while maintaining bone length, rotational alignment, and postsurgical mobility. The PBSS has been utilized in a case series of 41 fractures in 33 patients suffering osteoporotic long bone fractures. The initial results indicate that the use of the light-cured polymeric rod for this patient population provides excellent fixation and stability in compromised bone, with a superior complication profile. This paper describes the clinical uses, procedural details, indications for use, and the initial clinical findings of the PBSS. PMID:25540600

  13. Aging and skilled problem solving.

    PubMed

    Charness, N

    1981-03-01

    Information-processing models of problem solving too often are based on restrictive age ranges. On the other hand, gerontologists have investigated few problem-solving tasks and have rarely generated explicit models. As this article demonstrates, both fields can benefit by closer collaboration. One major issue in gerontology is whether aging is associated with irreversible decrement or developmental plasticity. If both processes occur, then an appropriate strategy for investigating aging is to equate age groups for molar problem-solving performance and search for differences in the underlying components. This strategy was adopted to examine the relation of age and skill to problem solving in chess. Chess players were selected to vary widely in age and skill such that these variables were uncorrelated. Problem-solving and memory tasks were administered. Skill level was the only significant predictor for accuracy in both a choose-a-move task and a speeded end-game evaluation task. Age (negatively) and skill (positively) jointly determined performance in an unexpected recall task. Efficient chunking in recall was positively related to skill, though negatively related to age. Recognition confidence, though not accuracy, was negatively related to age. Thus despite age-related declines in encoding and retrieval of information, older players match the problem-solving performance of equivalently skilled younger players. Apparently, they can search the problem space more efficiently, as evidenced by taking less time to select an equally good move. Models of chess skill that stress that role of encoding efficiency, as indexed by chunking in recall, need to be modified to account for performance over the life span.

  14. Symmetries in laminated composite plates

    NASA Technical Reports Server (NTRS)

    Noor, A. K.

    1976-01-01

    The different types of symmetry exhibited by laminated anisotropic fibrous composite plates are identified and contrasted with the symmetries of isotropic and homogeneous orthotropic plates. The effects of variations in the fiber orientation and the stacking sequence of the layers on the symmetries exhibited by composite plates are discussed. Both the linear and geometrically nonlinear responses of the plates are considered. A simple procedure is presented for exploiting the symmetries in the finite element analysis. Examples are given of square, skew and polygonal plates where use of symmetry concepts can significantly reduce the scope and cost of analysis.

  15. Robot, computer problem solving system

    NASA Technical Reports Server (NTRS)

    Becker, J. D.

    1972-01-01

    The development of a computer problem solving system is reported that considers physical problems faced by an artificial robot moving around in a complex environment. Fundamental interaction constraints with a real environment are simulated for the robot by visual scan and creation of an internal environmental model. The programming system used in constructing the problem solving system for the simulated robot and its simulated world environment is outlined together with the task that the system is capable of performing. A very general framework for understanding the relationship between an observed behavior and an adequate description of that behavior is included.

  16. Principles for Teaching Problem Solving. Technical Paper.

    ERIC Educational Resources Information Center

    Foshay, Rob; Kirkley, Jamie

    This Technical Paper focuses on principles for teaching problem solving. Part 1 addresses the need to teach problem solving. Part 2 defines problem solving skills, and describes: general problem solving models of the 1960s and 1970s, current problem solving models, declarative knowledge, mental models, expert versus novice knowledge, procedural…

  17. [A turning point in the therapeutic history of open leg fractures: osteosynthesis coupled to the immediate dressing in the presence of major damage to the soft tissues].

    PubMed

    Vichard, P; Tropet, Y; Garbuio, P

    1999-01-01

    A brief history of the treatment of open leg fractures (OLF) points out the problems posed by the present therapy with regard to the soft tissues in the most serious cases (type III from cauchoix, Duparc, type III A and B from Gustilo). Which strategy should be foremost, knowing that the debridement, stabilization and cover are the three essential procedures? Rigorous debridement certainly carries unanimous approval but some are opposed to this procedure during the first few days. Also widely recognized is the beneficial aspect of early cover when regarding aseptic evolution, consolidation, low rate of complications, rehabilitation and the patient's helplessness. However, despite the well demonstrated results of BYRD [14] and GODINA [15] and because of the debridement concept and logistical insufficiencies, thorough treatment in a true emergency has not achieved full acceptance. In general, the majority of surgeons first clear, stabilize with the use of an external fixator in true emergency situations and cover several days later. For the past ten years, in real emergencies, in the Department of Orthopedics, Traumatology and Plastic Surgery at the Besançon University Hospital Center we have subscribed to a radical treatment which simultaneously combines debridement, osteosynthesis (locked centro-medullary nailing) and cover with the use of free flaps in the same operating period. A study based on 27 wounded patients seeks to validate the advantages of looked centro-medullary nailing over the use of an external fixator and the use of free flaps rather than local flaps in the most serious cases. PMID:10437287

  18. Hypervelocity impact on shielded plates

    NASA Technical Reports Server (NTRS)

    Smith, James P.

    1993-01-01

    A ballistic limit equation for hypervelocity impact on thin plates is derived analytically. This equation applies to cases of impulsive impact on a plate that is protected by a multi-shock shield, and it is valid in the range of velocity above 6 km/s. Experimental tests were conducted at the NASA Johnson Space Center on square aluminum plates. Comparing the center deflections of these plates with the theoretical deflections of a rigid-plastic plate subjected to a blast load, one determines the dynamic yield strength of the plate material. The analysis is based on a theory for the expansion of the fragmented projectile and on a simple failure criterion. Curves are presented for the critical projectile radius versus the projectile velocity, and for the critical plate thickness versus the velocity. These curves are in good agreement with curves that have been generated empirically.

  19. Fuel cell end plate structure

    DOEpatents

    Guthrie, Robin J.; Katz, Murray; Schroll, Craig R.

    1991-04-23

    The end plates (16) of a fuel cell stack (12) are formed of a thin membrane. Pressure plates (20) exert compressive load through insulation layers (22, 26) to the membrane. Electrical contact between the end plates (16) and electrodes (50, 58) is maintained without deleterious making and breaking of electrical contacts during thermal transients. The thin end plate (16) under compressive load will not distort with a temperature difference across its thickness. Pressure plate (20) experiences a low thermal transient because it is insulated from the cell. The impact on the end plate of any slight deflection created in the pressure plate by temperature difference is minimized by the resilient pressure pad, in the form of insulation, therebetween.

  20. Reverse distal femoral locking compression plate a salvage option in nonunion of proximal femoral fractures

    PubMed Central

    Dumbre Patil, Sampat S; Karkamkar, Sachin S; Patil, Vaishali S Dumbre; Patil, Shailesh S; Ranaware, Abhijeet S

    2016-01-01

    Background: When primary fixation of proximal femoral fractures with implants fails, revision osteosynthesis may be challenging. Tracts of previous implants and remaining insufficient bone stock in the proximal femur pose unique problems for the treatment. Intramedullary implants like proximal femoral nail (PFN) or surface implants like Dynamic Condylar Screw (DCS) are few of the described implants for revision surgery. There is no evidence in the literature to choose one implant over the other. We used the reverse distal femur locking compression plate (LCP) of the contralateral side in such cases undergoing revision surgery. This implant has multiple options of fixation in proximal femur and its curvature along the length matches the anterior bow of the femur. We aimed to evaluate the efficacy of this implant in salvage situations. Materials and Methods: Twenty patients of failed primary proximal femoral fractures who underwent revision surgery with reverse distal femoral locking plate from February 2009 to November 2012 were included in this retrospective study. There were 18 subtrochanteric fractures and two ipsilateral femoral neck and shaft fractures, which exhibited delayed union or nonunion. The study included 14 males and six females. The mean patient age was 43.6 years (range 22–65 years) and mean followup period was 52.1 months (range 27–72 months). Delayed union was considered when clinical and radiological signs of union failed to progress at the end of four months from initial surgery. Results: All fractures exhibited union without any complications. Union was assessed clinically and radiologically. One case of ipsilateral femoral neck and shaft fracture required bone grafting at the second stage for delayed union of the femoral shaft fracture. Conclusions: Reverse distal femoral LCP of the contralateral side can be used as a salvage option for failed fixation of proximal femoral fractures exhibiting nonunion. PMID:27512218

  1. Sudden stretching of a four layered composite plate

    NASA Technical Reports Server (NTRS)

    Sih, G. C.; Chen, E. P.

    1980-01-01

    An approximate theory of laminated plates is developed by assuming that the extensioral and thickness mode of vibration are coupled. The mixed boundary value crack problem of a four layered composite plate is solved. Dynamic stress intensity factors for a crack subjected to suddenly applied stress are found to vary as a function of time and depend on the material properties of the laminate. Stress intensification in the region near the crack front can be reduced by having the shear modulus of the inner layers to be larger than that of the outer layers.

  2. Common Core: Solve Math Problems

    ERIC Educational Resources Information Center

    Strom, Erich

    2012-01-01

    The new common core standards for mathematics demand that students (and teachers!) exhibit deeper conceptual understanding. That's music to the ears of education professor John Tapper, who says teachers have overemphasized teaching procedures--and getting right answers. In his new book, "Solving for Why," he makes a powerful case for moving beyond…

  3. Robot computer problem solving system

    NASA Technical Reports Server (NTRS)

    Becker, J. D.; Merriam, E. W.

    1974-01-01

    The conceptual, experimental, and practical aspects of the development of a robot computer problem solving system were investigated. The distinctive characteristics were formulated of the approach taken in relation to various studies of cognition and robotics. Vehicle and eye control systems were structured, and the information to be generated by the visual system is defined.

  4. Gender and Mathematical Problem Solving.

    ERIC Educational Resources Information Center

    Duffy, Jim; Gunther, Georg; Walters, Lloyd

    1997-01-01

    Studied the relationship between gender and mathematical problem solving in 83 male and 76 female high achieving Canadian 12-year-olds. Gender differences were found on the Canadian Test of Basic Skills but not on the GAUSS assessment. Implications for the discussion of the origin of gender differences in mathematics are discussed. (SLD)

  5. Students' Problem Solving and Justification

    ERIC Educational Resources Information Center

    Glass, Barbara; Maher, Carolyn A.

    2004-01-01

    This paper reports on methods of students' justifications of their solution to a problem in the area of combinatorics. From the analysis of the problem solving of 150 students in a variety of settings from high-school to graduate study, four major forms of reasoning evolved: (1) Justification by Cases, (2) Inductive Argument, (3) Elimination…

  6. Customer Service & Team Problem Solving.

    ERIC Educational Resources Information Center

    Martin, Sabrina Budasi

    This curriculum guide provides materials for a six-session, site-specific training course in customer service and team problem solving for the Claretian Medical Center. The course outline is followed the six lesson plans. Components of each lesson plan include a list of objectives, an outline of activities and discussion topics for the lesson,…

  7. Problem-Solving Test: Pyrosequencing

    ERIC Educational Resources Information Center

    Szeberenyi, Jozsef

    2013-01-01

    Terms to be familiar with before you start to solve the test: Maxam-Gilbert sequencing, Sanger sequencing, gel electrophoresis, DNA synthesis reaction, polymerase chain reaction, template, primer, DNA polymerase, deoxyribonucleoside triphosphates, orthophosphate, pyrophosphate, nucleoside monophosphates, luminescence, acid anhydride bond,…

  8. Human Problem Solving in 2006

    ERIC Educational Resources Information Center

    Pizlo, Zygmunt

    2007-01-01

    This paper presents a bibliography of a little more than 100 references related to human problem solving, arranged by subject matter. The references were taken from PsycInfo and Compendex databases. Only journal papers, books and dissertations are included. The topics include human development, education, neuroscience, research in applied…

  9. Robot computer problem solving system

    NASA Technical Reports Server (NTRS)

    Becker, J. D.; Merriam, E. W.

    1974-01-01

    The conceptual, experimental, and practical phases of developing a robot computer problem solving system are outlined. Robot intelligence, conversion of the programming language SAIL to run under the THNEX monitor, and the use of the network to run several cooperating jobs at different sites are discussed.

  10. Sex Differences in Problem Solving.

    ERIC Educational Resources Information Center

    Johnson, Edward S.

    1984-01-01

    Nine experiments were performed to verify and extend studies on sex differences in problem solving conducted in the 1950s by Sweeney, Carey, Milton, Nakamura, and Berry. A 20-item problem set was administered to over 1,000 college students. Results indicated a male advantage, averaging 35 percent, virtually identical with 1950s results. (Author/BS)

  11. Problem Solving through Paper Folding

    ERIC Educational Resources Information Center

    Wares, Arsalan

    2014-01-01

    The purpose of this article is to describe a couple of challenging mathematical problems that involve paper folding. These problem-solving tasks can be used to foster geometric and algebraic thinking among students. The context of paper folding makes some of the abstract mathematical ideas involved relatively concrete. When implemented…

  12. Promote Problem-Solving Discourse

    ERIC Educational Resources Information Center

    Bostic, Jonathan; Jacobbe, Tim

    2010-01-01

    Fourteen fifth-grade students gather at the front of the classroom as their summer school instructor introduces Jonathan Bostic as the mathematics teacher for the week. Before examining any math problems, Bostic sits at eye level with the students and informs them that they will solve problems over the next four days by working individually as…

  13. Teaching through Collaborative Problem Solving.

    ERIC Educational Resources Information Center

    Blandford, A. E.

    1994-01-01

    Discussion of a prototype intelligent education system called WOMBAT (Weighted Objectives Method by Arguing with the Tutor) focuses on dialogue and negotiation in collaborative problem solving. The results of a formative evaluation, in which the system was used by 10 subjects who commented on various aspects of the design, are presented. (Contains…

  14. Time Out for Problem Solving.

    ERIC Educational Resources Information Center

    Champagne, Audrey B.; And Others

    Teachers in elementary schools, supervisors of instruction, and other educational practitioners are the primary audience for this publication. The paper presents philosophical, psychological, and practical reasons for including a problem-solving approach in elementary school instruction. It draws on the writings of John Dewey, Jean Piaget, James…

  15. Supporting Problem Solving in PBL

    ERIC Educational Resources Information Center

    Jonassen, David

    2011-01-01

    Although the characteristics of PBL (problem focused, student centered, self-directed, etc.) are well known, the components of a problem-based learning environment (PBLE) and the cognitive scaffolds necessary to support learning to solve different kinds of problems with different learners is less clear. This paper identifies the different…

  16. Vibration characteristics of rectangular plate in compressible inviscid fluid

    NASA Astrophysics Data System (ADS)

    Liao, Chan-Yi; Ma, Chien-Ching

    2016-02-01

    This paper presents a mathematical derivation of the vibration characteristics of an elastic thin plate placed at the bottom of a three dimensional rectangular container filled with compressible inviscid fluid. A set of beam functions is used as the admissible functions of the plate in a fluid-plate system, and the motion of the fluid induced by the deformation of the plate is obtained from a three-dimensional acoustic equation. Pressure from the fluid over the fluid-plate interface is integrated to form a virtual mass matrix. The frequency equation of the fluid-plate system is derived by combining mass, stiffness, and the virtual mass matrix. Solving the frequency equation makes it possible to obtain the dynamic characteristic of the fluid-plate system, such as resonant frequencies, corresponding mode shapes, and velocity of the fluid. Numerical calculations were performed for plates coupled with fluids with various degrees of compressibility to illustrate the difference between compressible and incompressible fluids in a fluid-plate system. The proposed method could be used to predict resonant frequencies and mode shapes with accuracy compared to that of incompressible fluid theory (IFT). The proposed method can be used to analyze cases involving high value of sound velocity, such as incompressible fluids. When the sound velocity approaches infinity, the results obtained for compressible fluids are similar to those of incompressible fluids. We also examined the influence of fluid compressibility on vibration characteristics in which a decrease in sound velocity was shown to correspond to a decrease in resonant frequency. Additional modes, not observed in incompressible fluids, were obtained in cases of low sound velocity, particularly at higher resonant frequencies. Fluid velocity plots clearly reveal that the additional resonant modes can be attributed to the compressible behavior of the fluid.

  17. The surface and through crack problems in layered orthotropic plates

    NASA Technical Reports Server (NTRS)

    Erdogan, Fazil; Wu, Binghua

    1991-01-01

    An analytical method is developed for a relatively accurate calculation of Stress Intensity Factors in a laminated orthotropic plate containing a through or part-through crack. The laminated plate is assumed to be under bending or membrane loading and the mode 1 problem is considered. First three transverse shear deformation plate theories (Mindlin's displacement based first-order theory, Reissner's stress-based first-order theory, and a simple-higher order theory due to Reddy) are reviewed and examined for homogeneous, laminated and heterogeneous orthotropic plates. Based on a general linear laminated plate theory, a method by which the stress intensity factors can be obtained in orthotropic laminated and heterogeneous plates with a through crack is developed. Examples are given for both symmetrically and unsymmetrically laminated plates and the effects of various material properties on the stress intensity factors are studied. In order to implement the line-spring model which is used later to study the surface crack problem, the corresponding plane elasticity problem of a two-bonded orthotropic plated containing a crack perpendicular to the interface is also considered. Three different crack profiles: an internal crack, an edge crack, and a crack terminating at the interface are considered. The effect of the different material combinations, geometries, and material orthotropy on the stress intensity factors and on the power of stress singularity for a crack terminating at the interface is fully examined. The Line Spring model of Rice and Levy is used for the part-through crack problem. The surface crack is assumed to lie in one of the two-layered laminated orthotropic plates due to the limitation of the available plane strain results. All problems considered are of the mixed boundary value type and are reduced to Cauchy type of singular integral equations which are then solved numerically.

  18. Plated wire memory subsystem

    NASA Technical Reports Server (NTRS)

    Carpenter, K. H.

    1974-01-01

    The design, construction, and test history of a 4096 word by 18 bit random access NDRO Plated Wire Memory for use in conjunction with a spacecraft input/output and central processing unit is reported. A technical and functional description is given along with diagrams illustrating layout and systems operation. Test data is shown on the procedures and results of system level and memory stack testing, and hybrid circuit screening. A comparison of the most significant physical and performance characteristics of the memory unit versus the specified requirements is also included.

  19. Shuttle plate braiding machine

    NASA Technical Reports Server (NTRS)

    Huey, Jr., Cecil O. (Inventor)

    1994-01-01

    A method and apparatus for moving yarn in a selected pattern to form a braided article. The apparatus includes a segmented grid of stationary support elements and a plurality of shuttles configured to carry yarn. The shuttles are supported for movement on the grid assembly and each shuttle includes a retractable plunger for engaging a reciprocating shuttle plate that moves below the grid assembly. Such engagement at selected times causes the shuttles to move about the grid assembly in a selected pattern to form a braided article of a particular geometry.

  20. Reduced hydrogen cadmium plating

    SciTech Connect

    Hoeller, T.; Ross, L. ); Varma, R. ); Agarwala, V.S. )

    1991-01-01

    This paper demonstrates the advantages of using a periodic reverse pulse plating method, incorporating a fast cathodic pulse which is separated from the subsequent anodic/cathodic pulses by a long rest period in producing silvery cadmium coatings on steel from aqueous fluoroborate electrolyte. Also, the deposition obtained by combination of pulse currents and turbulent electrolyte flow system (forced convection of electrolyte, Re {approximately} 20-25,000) result in a near hydrogen-free electrodeposition of fine- grained cadmium. This is confirmed by the determination of diffusible hydrogen by the electrochemical (Barnach Electrode) method.

  1. Genetics problem solving and worldview

    NASA Astrophysics Data System (ADS)

    Dale, Esther

    The research goal was to determine whether worldview relates to traditional and real-world genetics problem solving. Traditionally, scientific literacy emphasized content knowledge alone because it was sufficient to solve traditional problems. The contemporary definition of scientific literacy is, "The knowledge and understanding of scientific concepts and processes required for personal decision-making, participation in civic and cultural affairs and economic productivity" (NRC, 1996). An expanded definition of scientific literacy is needed to solve socioscientific issues (SSI), complex social issues with conceptual, procedural, or technological associations with science. Teaching content knowledge alone assumes that students will find the scientific explanation of a phenomenon to be superior to a non-science explanation. Formal science and everyday ways of thinking about science are two different cultures (Palmer, 1999). Students address this rift with cognitive apartheid, the boxing away of science knowledge from other types of knowledge (Jedege & Aikenhead, 1999). By addressing worldview, cognitive apartheid may decrease and scientific literacy may increase. Introductory biology students at the University of Minnesota during fall semester 2005 completed a written questionnaire-including a genetics content-knowledge test, four genetic dilemmas, the Worldview Assessment Instrument (WAI) and some items about demographics and religiosity. Six students responded to the interview protocol. Based on statistical analysis and interview data, this study concluded the following: (1) Worldview, in the form of metaphysics, relates to solving traditional genetic dilemmas. (2) Worldview, in the form of agency, relates to solving traditional genetics problems. (3) Thus, worldview must be addressed in curriculum, instruction, and assessment.

  2. Dynamic stiffness matrix of a rectangular plate for the general case

    NASA Astrophysics Data System (ADS)

    Banerjee, J. R.; Papkov, S. O.; Liu, X.; Kennedy, D.

    2015-04-01

    The dynamic stiffness matrix of a rectangular plate for the most general case is developed by solving the bi-harmonic equation and finally casting the solution in terms of the force-displacement relationship of the freely vibrating plate. Essentially the frequency dependent dynamic stiffness matrix of the plate when all its sides are free is derived, making it possible to achieve exact solution for free vibration of plates or plate assemblies with any boundary conditions. Previous research on the dynamic stiffness formulation of a plate was restricted to the special case when the two opposite sides of the plate are simply supported. This restriction is quite severe and made the general purpose application of the dynamic stiffness method impossible. The theory developed in this paper overcomes this long-lasting restriction. The research carried out here is basically fundamental in that the bi-harmonic equation which governs the free vibratory motion of a plate in harmonic oscillation is solved in an exact sense, leading to the development of the dynamic stiffness method. It is significant that the ingeniously sought solution presented in this paper is completely general, covering all possible cases of elastic deformations of the plate. The Wittrick-Williams algorithm is applied to the ensuing dynamic stiffness matrix to provide solutions for some representative problems. A carefully selected sample of mode shapes is also presented.

  3. Plating on difficult-to-plate metals: what's new

    SciTech Connect

    Wiesner, H.J.

    1980-07-30

    Some of the changes since 1970 in procedures for plating on such materials as titanium, molybdenum, silicon, aluminum, and gallium arsenide are summarized. While basic procedures for plating some of these materials were developed as many as 30 to 40 years ago, changes in the end uses of the plated products have necessitated new plating processes. In some cases, vacuum techniques - such as ion bombardment, ion implantation, and vacuum metallization - have been introduced to improve the adhesion of electrodeposits. In other cases, these techniques have been used to deposit materials upon which electrodeposits are required.

  4. The Application of Optimisation Methods to Constrain Absolute Plate Motions

    NASA Astrophysics Data System (ADS)

    Tetley, M. G.; Williams, S.; Hardy, S.; Müller, D.

    2015-12-01

    Plate tectonic reconstructions are an excellent tool for understanding the configuration and behaviour of continents through time on both global and regional scales, and are relatively well understood back to ~200 Ma. However, many of these models represent only relative motions between continents, providing little information of absolute tectonic motions and their relationship with the deep Earth. Significant issues exist in solving this problem, including how to combine constraints from multiple, diverse data into a unified model of absolute plate motions; and how to address uncertainties both in the available data, and in the assumptions involved in this process (e.g. hotspot motion, true polar wander). In deep time (pre-Pangea breakup), plate reconstructions rely more heavily on paleomagnetism, but these data often imply plate velocities much larger than those observed since the breakup of the supercontinent Pangea where plate velocities are constrained by the seafloor spreading record. Here we present two complementary techniques to address these issues, applying parallelized numerical methods to quantitatively investigate absolute plate motions through time. Firstly, we develop a data-fit optimized global absolute reference frame constrained by kinematic reconstruction data, hotspot-trail observations, and trench migration statistics. Secondly we calculate optimized paleomagnetic data-derived apparent polar wander paths (APWPs) for both the Phanerozoic and Precambrian. Paths are generated from raw pole data with optimal spatial and temporal pole configurations calculated using all known uncertainties and quality criteria to produce velocity-optimized absolute motion paths through deep time.

  5. Tectonics of the Easter plate

    NASA Technical Reports Server (NTRS)

    Engeln, J. F.; Stein, S.

    1984-01-01

    A new model for the Easter plate is presented in which rift propagation has resulted in the formation of a rigid plate between the propagating and dying ridges. The distribution of earthquakes, eleven new focal mechanisms, and existing bathymetric and magnetic data are used to describe the tectonics of this area. Both the Easter-Nazca and Easter-Pacific Euler poles are sufficiently close to the Easter plate to cause rapid changes in rates and directions of motion along the boundaries. The east and west boundaries are propagating and dying ridges; the southwest boundary is a slow-spreading ridge and the northern boundary is a complex zone of convergent and transform motion. The Easter plate may reflect the tectonics of rift propagation on a large scale, where rigid plate tectonics requires boundary reorientation. Simple schematic models to illustrate the general features and processes which occur at plates resulting from large-scale rift propagation are used.

  6. Localised Plate Motion on Venus

    NASA Astrophysics Data System (ADS)

    Ghail, R. C.

    1996-03-01

    The volcanic and tectonic features observed in Dali Vinculum, Parga Vinculum and Imdr Regio are concentrated at long, narrow, curvilinear zones, with relatively minor volcanism and tectonism between these zones. These zones, whilst more diffuse than terrestrial plate boundaries, nevertheless define the margins of tectonic plates. In contrast to Earth, however, it appears that venusian plates are neither created nor destroyed by lateral motion. Rather, plates are thinned and intruded at vincula plate boundaries, vertically accreted by small-scale intra-plate (planitia) volcanism and perhaps destroyed by delamination of thickened crust in tesserae and montane regions such as Thetis Regio and Ishtar Terra. The diversity in age both between and within these three areas together with the evidence for infrequent, small scale resurfacing in the planitiae are difficult to reconcile with a non-uniformitarian geological process.

  7. Quantum Computing: Solving Complex Problems

    ScienceCinema

    DiVincenzo, David [IBM Watson Research Center

    2016-07-12

    One of the motivating ideas of quantum computation was that there could be a new kind of machine that would solve hard problems in quantum mechanics. There has been significant progress towards the experimental realization of these machines (which I will review), but there are still many questions about how such a machine could solve computational problems of interest in quantum physics. New categorizations of the complexity of computational problems have now been invented to describe quantum simulation. The bad news is that some of these problems are believed to be intractable even on a quantum computer, falling into a quantum analog of the NP class. The good news is that there are many other new classifications of tractability that may apply to several situations of physical interest.

  8. An NOy* Algorithm for SOLVE

    NASA Technical Reports Server (NTRS)

    Loewenstein, M.; Greenblatt. B. J.; Jost, H.; Podolske, J. R.; Elkins, Jim; Hurst, Dale; Romanashkin, Pavel; Atlas, Elliott; Schauffler, Sue; Donnelly, Steve; Condon, Estelle (Technical Monitor)

    2000-01-01

    De-nitrification and excess re-nitrification was widely observed by ER-2 instruments in the Arctic vortex during SOLVE in winter/spring 2000. Analyses of these events requires a knowledge of the initial or pre-vortex state of the sampled air masses. The canonical relationship of NOy to the long-lived tracer N2O observed in the unperturbed stratosphere is generally used for this purpose. In this paper we will attempt to establish the current unperturbed NOy:N2O relationship (NOy* algorithm) using the ensemble of extra-vortex data from in situ instruments flying on the ER-2 and DC-8, and from the Mark IV remote measurements on the OMS balloon. Initial analysis indicates a change in the SOLVE NOy* from the values predicted by the 1994 Northern Hemisphere NOy* algorithm which was derived from the observations in the ASHOE/MAESA campaign.

  9. Solving higher curvature gravity theories

    NASA Astrophysics Data System (ADS)

    Chakraborty, Sumanta; SenGupta, Soumitra

    2016-10-01

    Solving field equations in the context of higher curvature gravity theories is a formidable task. However, in many situations, e.g., in the context of f( R) theories, the higher curvature gravity action can be written as an Einstein-Hilbert action plus a scalar field action. We show that not only the action but the field equations derived from the action are also equivalent, provided the spacetime is regular. We also demonstrate that such an equivalence continues to hold even when the gravitational field equations are projected on a lower-dimensional hypersurface. We have further addressed explicit examples in which the solutions for Einstein-Hilbert and a scalar field system lead to solutions of the equivalent higher curvature theory. The same, but on the lower-dimensional hypersurface, has been illustrated in the reverse order as well. We conclude with a brief discussion on this technique of solving higher curvature field equations.

  10. Maze Solving by Chemotactic Droplets

    SciTech Connect

    Lagzi, Istvan; Soh, Siowling; Wesson, Paul J.; Browne, Kevin P.; Grzybowski, Bartosz A.

    2010-01-11

    Droplets emitting surface-active chemicals exhibit chemotaxis toward low-pH regions. Such droplets are self-propelled and navigate through a complex maze to seek a source of acid placed at one of the maze’s exits. In doing so, the droplets find the shortest path through the maze. Chemotaxis and maze solving are due to an interplay between acid/base chemistry and surface tension effects.

  11. Channel plate for DNA sequencing

    DOEpatents

    Douthart, R.J.; Crowell, S.L.

    1998-01-13

    This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface. 15 figs.

  12. Ion plating for the future

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1981-01-01

    The ion plating techniques are classified relative to the instrumental set up, evaporation media, and mode of transport. A distinction is drawn between the low vacuum (plasma) and high vacuum (ion beam) techniques. Ion plating technology is discussed at the fundamental and industrial level. At the fundamental level, the capabilities and limitations of the plasma (evaporant flux) and film characteristics are evaluated. And on the industrial level, the performance and potential uses of ion plated films are discussed.

  13. Multiple plate hydrostatic viscous damper

    NASA Technical Reports Server (NTRS)

    Ludwig, L. P. (Inventor)

    1981-01-01

    A device for damping radial motion of a rotating shaft is described. The damper comprises a series of spaced plates extending in a radial direction. A hydraulic piston is utilized to place a load in these plates. Each annular plate is provided with a suitable hydrostatic bearing geometry on at least one of its faces. This structure provides a high degree of dampening in a rotor case system of turbomachinery in general. The damper is particularly useful in gas turbine engines.

  14. Plate heat exchanger design theory

    NASA Astrophysics Data System (ADS)

    Shah, R. K.; Wanniarachchi, A. S.

    Plate heat exchangers are commonly used in hygienic applications as well as in chemical processing and other industrial applications. Pertinent information on plate exchangers from a designer's point of view is summarized to provide a basic insight into performance behavior of chevron plates. Basic design methods are presented and a method of coupling between heat transfer and pressure drop is introduced. A step by step design procedure for rating and sizing problems is outlined.

  15. Channel plate for DNA sequencing

    DOEpatents

    Douthart, Richard J.; Crowell, Shannon L.

    1998-01-01

    This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface.

  16. Light propagation in biological tissues containing an absorbing plate.

    PubMed

    Kim, Arnold D

    2004-01-20

    We study light propagation in biological tissue containing an absorbing obstacle. In particular, we solve the infinite-domain problem in which an absorbing plate of negligible thickness prevents a portion of the light from the source from reaching the detector plane. Inasmuch as scattering in the medium is sharply peaked in the forward direction, we replace the governing radiative transport equation with the Fokker-Planck equation. The problem is solved first by application of the Kirchhoff approximation to determine the secondary source distribution over the surface of the plate. That result is propagated to the detector plane by use of Green's function. The Green's function is given as an expansion of plane-wave modes that are calculated numerically. The radiance is shown to obey Babinet's principle. Results from numerical computations that demonstrate this theory are shown.

  17. Glass-bead peen plating

    NASA Technical Reports Server (NTRS)

    Graves, J. R.

    1974-01-01

    Peen plating of aluminum, copper, and nickel powders was investigated. Only aluminum was plated successfully within the range of peen plating conditions studied. Optimum plating conditions for aluminum were found to be: (1) bead/powder mixture containing 25 to 35% powder by weight, (2) peening intensity of 0.007A as measured by Almen strip, and (3) glass impact bead diameter of at least 297 microns (0.0117 inches) for depositing-100 mesh aluminum powder. No extensive cleaning or substrate preparation is required beyond removing loose dirt or heavy oil.

  18. True Shear Parallel Plate Viscometer

    NASA Technical Reports Server (NTRS)

    Ethridge, Edwin; Kaukler, William

    2010-01-01

    This viscometer (which can also be used as a rheometer) is designed for use with liquids over a large temperature range. The device consists of horizontally disposed, similarly sized, parallel plates with a precisely known gap. The lower plate is driven laterally with a motor to apply shear to the liquid in the gap. The upper plate is freely suspended from a double-arm pendulum with a sufficiently long radius to reduce height variations during the swing to negligible levels. A sensitive load cell measures the shear force applied by the liquid to the upper plate. Viscosity is measured by taking the ratio of shear stress to shear rate.

  19. Carbon-assisted flyer plates

    DOEpatents

    Stahl, David B.; Paisley, Dennis L.

    1994-01-01

    A laser driven flyer plate utilizing an optical fiber connected to a laser. The end of the optical fiber has a layer of carbon and a metal layer deposited onto it. The carbon layer provides the laser induced plasma which is superior to the plasma produced from most metals. The carbon layer plasma is capable of providing a flatter flyer plate, converting more of the laser energy to driving plasma, promoting a higher flyer plate acceleration, and providing a more uniform pulse behind the plate. In another embodiment, the laser is in optical communication with a substrate onto which a layer of carbon and a layer of metal have been deposited.

  20. Natural Frequencies of Rectangular Plate With- and Without-Rotary Inertia

    NASA Astrophysics Data System (ADS)

    Kalita, Kanak; Haldar, Salil

    2016-07-01

    A nine-node isoparametric plate element, in conjunction with first-order shear deformation theory, was used for free vibration analysis of rectangular plates. Both thick and thin plate problems were solved for various aspect ratios and boundary conditions. In this work, the primary focus is on the effect of rotary inertia on the natural frequencies of rectangular plates. It is found that rotary inertia significantly affects thick plates, while it can be ignored for thin plates. The numerical convergence is very rapid and based on a comparison with data from the literature; it is proposed that the present formulation can yield highly accurate results. Finally, some numerical solutions are provided here, which may serve as benchmarks for future research on similar problems.

  1. Vibration Analysis of Corner Supported Mindlin Plates of Arbitrary Shape Using the Lagrange Multiplier Method

    NASA Astrophysics Data System (ADS)

    Kitipornchai, S.; Xiang, Y.; Liew, K. M.

    1994-06-01

    This paper presents the first known solutions of the problem of free flexural vibration of corner supported Mindlin plates of arbitrary shape. A hybrid numerical approach combining the Rayleigh-Ritz method and the Lagrange multiplier method has been developed to solve the plate vibration problem. The algorithm uses the pb-2 shape functions to account for different geometries, and Lagrange multipliers to impose zero lateral deflection constraints at plate corners. The method of solution is applicable to arbitrarily shaped plates with corner supports. In this paper, however, only triangular, skew and annular sector plates are chosen for the purpose of demonstration. Some comparison studies for corner supported thin square plates are made to verify the accuracy of the derived solutions.

  2. Modeling of composite beams and plates for static and dynamic analysis

    NASA Technical Reports Server (NTRS)

    Hodges, Dewey H.

    1992-01-01

    A rigorous theory and the corresponding computational algorithms were developed for through-the-thickness analysis of composite plates. This type of analysis is needed in order to find the elastic stiffness constants of a plate. Additionally, the analysis is used to post-process the resulting plate solution in order to find approximate three-dimensional displacement, strain, and stress distributions throughout the plate. It was decided that the variational-asymptotical method (VAM) would serve as a suitable framework in which to solve these types of problems. Work during this reporting period has progressed along two lines: (1) further evaluation of neo-classical plate theory (NCPT) as applied to shear-coupled laminates; and (2) continued modeling of plates with nonuniform thickness.

  3. Theoretical analysis on capillary adhesion of microsized plates with a substrate

    NASA Astrophysics Data System (ADS)

    Liu, Jian Lin

    2010-05-01

    The stiction of a thin plate induced by the capillary force has attracted much attention in the broad range of applications. A novel method is presented to calculate the capillary adhesion problem of the plate through analytical method. The expressions of the surface energy, the strain energy and the total potential energy of the plate-substrate system have been analyzed and delineated. By means of continuum mechanics and the principle of minimum potential energy, the governing equation of the plate with an arbitrary shape and the corresponding transversality boundary condition due to the moving bound have been derived. Then the critical adhesion radius of the circular plate has been solved according to the supplementary transversality condition. Thus the deflections of the plates are analytically calculated with different critical adhesion radii. The results may be beneficial to the engineering application and the micro/nano-measurement.

  4. The treatment of complex proximal humeral fractures: analysis of the results of 55 cases treated with PHILOS plate.

    PubMed

    Fattoretto, D; Borgo, A; Iacobellis, C

    2016-08-01

    Complex proximal humerus fractures are often difficult to treat. Their frequency is high, especially in the elderly, and their treatment is still controversial. The aim of this study was to analyze the clinical and radiological results achieved by patients with complex proximal humerus fractures, treated with PHILOS plate only. A cohort of 55 patients was selected. The mean age was 63.4 (range 33-89), while the mean follow-up time was 21.5 months (range 6-75). Clinical outcome was evaluated with the "Constant-Murley shoulder score." All the informations about the presence of complications were gathered, and radiological images were used to calculate the head-shaft angle. The overall mean Constant score was 61.93 ± 18.59, the Individual CS was 70 ± 20 % and the Relative CS was 83 ± 23 %. No significant differences were found between fractures Neer 3 and Neer 4 and between the surgical approaches (delta-split vs. delto-pectoral). Six patients had a fracture with dislocation, seven patients (12.7 %) had complications while in four patients a head-shaft angle beyond the normal range was found. Osteosynthesis with PHILOS plate is stable in the greater part of the cases, and it allows an earlier rehabilitation and so a good functional result, which could be compromised by a prolonged immobilization. Therefore, PHILOS plate is a good option for the treatment of complex proximal humerus fractures.

  5. Intermittent plate tectonics?

    PubMed

    Silver, Paul G; Behn, Mark D

    2008-01-01

    Although it is commonly assumed that subduction has operated continuously on Earth without interruption, subduction zones are routinely terminated by ocean closure and supercontinent assembly. Under certain circumstances, this could lead to a dramatic loss of subduction, globally. Closure of a Pacific-type basin, for example, would eliminate most subduction, unless this loss were compensated for by comparable subduction initiation elsewhere. Given the evidence for Pacific-type closure in Earth's past, the absence of a direct mechanism for termination/initiation compensation, and recent data supporting a minimum in subduction flux in the Mesoproterozoic, we hypothesize that dramatic reductions or temporary cessations of subduction have occurred in Earth's history. Such deviations in the continuity of plate tectonics have important consequences for Earth's thermal and continental evolution.

  6. Downgoing plate controls on overriding plate deformation in subduction zones

    NASA Astrophysics Data System (ADS)

    Garel, Fanny; Davies, Rhodri; Goes, Saskia; Davies, Huw; Kramer, Stephan; Wilson, Cian

    2014-05-01

    Although subduction zones are convergent margins, deformation in the upper plate can be extensional or compressional and tends to change through time, sometimes in repeated episodes of strong deformation, e.g, phases of back-arc extension. It is not well understood what factors control this upper plate deformation. We use the code Fluidity, which uses an adaptive mesh and a free-surface formulation, to model a two-plate subduction system in 2-D. The model includes a composite temperature- and stress-dependent rheology, and plates are decoupled by a weak layer, which allows for free trench motion. We investigate the evolution of the state of stress and topography of the overriding plate during the different phases of the subduction process: onset of subduction, free-fall sinking in the upper mantle and interaction of the slab with the transition zone, here represented by a viscosity contrast between upper and lower mantle. We focus on (i) how overriding plate deformation varies with subducting plate age; (ii) how spontaneous and episodic back-arc spreading develops for some subduction settings; (iii) the correlation between overriding plate deformation and slab interaction with the transition zone; (iv) whether these trends resemble observations on Earth.

  7. 10. DETAIL OF BUILDER'S PLATE AT NORTH PORTAL. PLATE READS: ...

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

    10. DETAIL OF BUILDER'S PLATE AT NORTH PORTAL. PLATE READS: 1889, BUILT BY THE BERLIN IRON BRIDGE CO. EAST BERLIN CONN. DOUGLAS & JARVIS PAT. APT. 16, 1878, AP'L 17, 1885. A.P. FORESMAN, WM. S. STARR, T.J. STREBEIGH, COMMISSIONERS. - Pine Creek Bridge, River Road spanning Pine Creek, Jersey Shore, Lycoming County, PA

  8. Anticipating Student Responses to Improve Problem Solving

    ERIC Educational Resources Information Center

    Wallace, Ann H.

    2007-01-01

    This article illustrates how problem solving can be enhanced through careful planning and problem presentation. Often, students shut down or are turned off when presented with a problem to solve. The author describes how to motivate students to embrace a problem to be solved and provides helpful prompts to further the problem-solving process.…

  9. Journey toward Teaching Mathematics through Problem Solving

    ERIC Educational Resources Information Center

    Sakshaug, Lynae E.; Wohlhuter, Kay A.

    2010-01-01

    Teaching mathematics through problem solving is a challenge for teachers who learned mathematics by doing exercises. How do teachers develop their own problem solving abilities as well as their abilities to teach mathematics through problem solving? A group of teachers began the journey of learning to teach through problem solving while taking a…

  10. Assessing Algebraic Solving Ability: A Theoretical Framework

    ERIC Educational Resources Information Center

    Lian, Lim Hooi; Yew, Wun Thiam

    2012-01-01

    Algebraic solving ability had been discussed by many educators and researchers. There exists no definite definition for algebraic solving ability as it can be viewed from different perspectives. In this paper, the nature of algebraic solving ability in terms of algebraic processes that demonstrate the ability in solving algebraic problem is…

  11. Limit cycle oscillation of a fluttering cantilever plate

    NASA Technical Reports Server (NTRS)

    Dowell, Earl; Ye, Weiliang

    1991-01-01

    A response of a cantilever plate in high supersonic flow to a disturbance is considered. The Rayleigh-Ritz method is used to solve the nonlinear oscillation of a fluttering plate. It is found that the length-to-width ratio for a cantilever plate has a great effect on flutter amplitude of the limit cycle. For small length-to-width ratio, the dominant chordwise modes are translation and rotation. It is suggested that higher bending modes must be included to obtain an accurate prediction of the flutter onset and limit cycle oscillation. For large length-to-width ratio, significant chordwise bending is apparent in the flutter motion, with the trailing edge area having the largest motion.

  12. Method for conducting electroless metal-plating processes

    DOEpatents

    Petit, George S.; Wright, Ralph R.

    1978-01-01

    This invention is an improved method for conducting electroless metal-plating processes in a metal tank which is exposed to the plating bath. The invention solves a problem commonly encountered in such processes: how to determine when it is advisable to shutdown the process in order to clean and/or re-passivate the tank. The new method comprises contacting the bath with a current-conducting, non-catalytic probe and, during plating operations, monitoring the gradually changing difference in electropotential between the probe and tank. It has been found that the value of this voltage is indicative of the extent to which nickel-bearing decomposition products accumulate on the tank. By utilizing the voltage to determine when shutdown for cleaning is advisable, the operator can avoid premature shutdown and at the same time avoid prolonging operations to the point that spontaneous decomposition occurs.

  13. Plate tectonics conserves angular momentum

    NASA Astrophysics Data System (ADS)

    Bowin, C.

    2010-03-01

    A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4+27 kg m2 s-1). Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates). Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies revealed by geoid anomalies of the degree 4-10 packet of the Earth's spherical harmonic coefficients. These linear positive geoid anomalies underlie plate subduction zones and are presumed due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth). The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant

  14. Plate tectonics, damage and inheritance

    NASA Astrophysics Data System (ADS)

    Bercovici, David; Ricard, Yanick

    2014-04-01

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4 billion years ago) and global tectonics (approximately 3 billion years ago) suggests that plates and plate boundaries became widespread over a period of 1 billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates.

  15. Plate tectonics, damage and inheritance.

    PubMed

    Bercovici, David; Ricard, Yanick

    2014-04-24

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4 billion years ago) and global tectonics (approximately 3 billion years ago) suggests that plates and plate boundaries became widespread over a period of 1 billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates. PMID:24717430

  16. Plate tectonics, damage and inheritance.

    PubMed

    Bercovici, David; Ricard, Yanick

    2014-04-24

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4 billion years ago) and global tectonics (approximately 3 billion years ago) suggests that plates and plate boundaries became widespread over a period of 1 billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates.

  17. Structured problem solving for materiel managers.

    PubMed

    Samelson, Q B

    1998-05-01

    A structured approach to problem solving and solution documentation is one of the keys to continuous improvement. Without it, it is quite possible to solve the wrong problem, to solve the right problem in the wrong way, or (maybe worst of all) to solve the same problem over and over again. Companies that have figured out how to solve the right problems in the right way, once and for all, will ultimately move forward much faster than their competitors.

  18. Resistive Plate Chambers: electron transport and modeling

    NASA Astrophysics Data System (ADS)

    Bošnjaković, D.; Petrović, Z. Lj; Dujko, S.

    2014-12-01

    We study the electron transport in gas mixtures used by Resistive Plate Chambers (RPCs) in high energy physics experiments at CERN. Calculations are performed using a multi term theory for solving the Boltzmann equation. We identify the effects induced by non-conservative nature of electron attachment, including attachment heating of electrons and negative differential conductivity (NDC). NDC was observed only in the bulk component of drift velocity. Using our Monte Carlo technique, we calculate the spatially resolved transport properties in order to investigate the origin of these effects. We also present our microscopic approach to modeling of RPCs which is based on Monte Carlo method. Calculated results for a timing RPC show good agreement with an analytical model and experimental data. Different cross section sets for electron scattering in C2H2F4 are used for comparison and analysis.

  19. Solving the Dark Matter Problem

    ScienceCinema

    Baltz, Ted

    2016-07-12

    Cosmological observations have firmly established that the majority of matter in the universe is of an unknown type, called 'dark matter'. A compelling hypothesis is that the dark matter consists of weakly interacting massive particles (WIMPs) in the mass range around 100 GeV. If the WIMP hypothesis is correct, such particles could be created and studied at accelerators. Furthermore they could be directly detected as the primary component of our galaxy. Solving the dark matter problem requires that the connection be made between the two. We describe some theoretical and experimental avenues that might lead to this connection.

  20. Micro-channel plate detector

    SciTech Connect

    Elam, Jeffrey W.; Lee, Seon W.; Wang, Hsien -Hau; Pellin, Michael J.; Byrum, Karen; Frisch, Henry J.

    2015-09-22

    A method and system for providing a micro-channel plate detector. An anodized aluminum oxide membrane is provided and includes a plurality of nanopores which have an Al coating and a thin layer of an emissive oxide material responsive to incident radiation, thereby providing a plurality of radiation sensitive channels for the micro-channel plate detector.

  1. Metal vapor arc ion plating

    SciTech Connect

    Bertram, L.A.; Fisher, R.W.; Mattox, D.M.; Zanner, F.J.

    1986-09-09

    A method and apparatus for ion plating are described. The apparatus uses more negative than a first electrode voltage in a vacuum arc remelt system to attract low energy ions from the anode electrode to the article to be plated. 2 figs.

  2. Flat-plate heat pipe

    NASA Technical Reports Server (NTRS)

    Marcus, B. D.; Fleischman, G. L. (Inventor)

    1977-01-01

    Flat plate (vapor chamber) heat pipes were made by enclosing metal wicking between two capillary grooved flat panels. These heat pipes provide a unique configuration and have good capacity and conductance capabilities in zero gravity. When these flat plate vapor chamber heat pipes are heated or cooled, the surfaces are essentially isothermal, varying only 3 to 5 C over the panel surface.

  3. Metals plated on fluorocarbon polymers

    NASA Technical Reports Server (NTRS)

    Ford, H.; Krasinsky, J. B.; Vango, S. P.

    1964-01-01

    Electroplating lead on fluorocarbon polymer parts is accomplished by etching the parts to be plated with sodium, followed by successive depositions of silver and lead from ultrasonically agitated plating solutions. Metals other than lead may be electroplated on the silvered parts.

  4. Aseptic laboratory techniques: plating methods.

    PubMed

    Sanders, Erin R

    2012-05-11

    Microorganisms are present on all inanimate surfaces creating ubiquitous sources of possible contamination in the laboratory. Experimental success relies on the ability of a scientist to sterilize work surfaces and equipment as well as prevent contact of sterile instruments and solutions with non-sterile surfaces. Here we present the steps for several plating methods routinely used in the laboratory to isolate, propagate, or enumerate microorganisms such as bacteria and phage. All five methods incorporate aseptic technique, or procedures that maintain the sterility of experimental materials. Procedures described include (1) streak-plating bacterial cultures to isolate single colonies, (2) pour-plating and (3) spread-plating to enumerate viable bacterial colonies, (4) soft agar overlays to isolate phage and enumerate plaques, and (5) replica-plating to transfer cells from one plate to another in an identical spatial pattern. These procedures can be performed at the laboratory bench, provided they involve non-pathogenic strains of microorganisms (Biosafety Level 1, BSL-1). If working with BSL-2 organisms, then these manipulations must take place in a biosafety cabinet. Consult the most current edition of the Biosafety in Microbiological and Biomedical Laboratories (BMBL) as well as Material Safety Data Sheets (MSDS) for Infectious Substances to determine the biohazard classification as well as the safety precautions and containment facilities required for the microorganism in question. Bacterial strains and phage stocks can be obtained from research investigators, companies, and collections maintained by particular organizations such as the American Type Culture Collection (ATCC). It is recommended that non-pathogenic strains be used when learning the various plating methods. By following the procedures described in this protocol, students should be able to: Perform plating procedures without contaminating media. Isolate single bacterial colonies by the streak-plating

  5. Aseptic Laboratory Techniques: Plating Methods

    PubMed Central

    Sanders, Erin R.

    2012-01-01

    Microorganisms are present on all inanimate surfaces creating ubiquitous sources of possible contamination in the laboratory. Experimental success relies on the ability of a scientist to sterilize work surfaces and equipment as well as prevent contact of sterile instruments and solutions with non-sterile surfaces. Here we present the steps for several plating methods routinely used in the laboratory to isolate, propagate, or enumerate microorganisms such as bacteria and phage. All five methods incorporate aseptic technique, or procedures that maintain the sterility of experimental materials. Procedures described include (1) streak-plating bacterial cultures to isolate single colonies, (2) pour-plating and (3) spread-plating to enumerate viable bacterial colonies, (4) soft agar overlays to isolate phage and enumerate plaques, and (5) replica-plating to transfer cells from one plate to another in an identical spatial pattern. These procedures can be performed at the laboratory bench, provided they involve non-pathogenic strains of microorganisms (Biosafety Level 1, BSL-1). If working with BSL-2 organisms, then these manipulations must take place in a biosafety cabinet. Consult the most current edition of the Biosafety in Microbiological and Biomedical Laboratories (BMBL) as well as Material Safety Data Sheets (MSDS) for Infectious Substances to determine the biohazard classification as well as the safety precautions and containment facilities required for the microorganism in question. Bacterial strains and phage stocks can be obtained from research investigators, companies, and collections maintained by particular organizations such as the American Type Culture Collection (ATCC). It is recommended that non-pathogenic strains be used when learning the various plating methods. By following the procedures described in this protocol, students should be able to: ● Perform plating procedures without contaminating media. ● Isolate single bacterial colonies by the

  6. The moving plate capacitor paradox

    NASA Astrophysics Data System (ADS)

    Davis, B. R.; Abbott, D.; Parrondo, J. M. R.

    2000-03-01

    For the first time we describe an apparent paradox concerning a moving plate capacitor driven by thermal noise from a resistor. A demon restores the plates of the capacitor to their original position, only when the voltage across the capacitor is small—hence only small forces are present for the demon to work against. The demon has to work harder than this to avoid the situation of perpetual motion, but the question is how? We explore the concept of a moving plate capacitor, driven by noise, a step further by examining the case where the restoring force on the capacitor plates is provided by a simple spring, rather than some unknown demon. We display simulation results with interesting behavior, particularly where the capacitor plates collide with each other.

  7. SAMI Automated Plug Plate Configuration

    NASA Astrophysics Data System (ADS)

    Lorente, N. P. F.; Farrell, T.; Goodwin, M.

    2013-10-01

    The Sydney-AAO Multi-object Integral field spectrograph (SAMI) is a prototype wide-field system at the Anglo-Australian Telescope (AAT) which uses a plug-plate to mount its 13×61-core imaging fibre bundles (hexabundles) in the optical path at the telescope's prime focus. In this paper we describe the process of determining the positions of the plug-plate holes, where plates contain three or more stacked observation configurations. The process, which up until now has involved several separate processes and has required significant manual configuration and checking, is now being automated to increase efficiency and reduce error. This is carried out by means of a thin Java controller layer which drives the configuration cycle. This layer controls the user interface and the C++ algorithm layer where the plate configuration and optimisation is carried out. Additionally, through the Aladin display package, it provides visualisation and facilitates user verification of the resulting plates.

  8. Present-day plate motions

    NASA Technical Reports Server (NTRS)

    Minster, J. B.; Jordan, T. H.

    1977-01-01

    A data set comprising 110 spreading rates, 78 transform fault azimuths and 142 earthquake slip vectors was inverted to yield a new instantaneous plate motion model, designated RM2. The mean averaging interval for the relative motion data was reduced to less than 3 My. A detailed comparison of RM2 with angular velocity vectors which best fit the data along individual plate boundaries indicates that RM2 performs close to optimally in most regions, with several notable exceptions. On the other hand, a previous estimate (RM1) failed to satisfy an extensive set of new data collected in the South Atlantic Ocean. It is shown that RM1 incorrectly predicts the plate kinematics in the South Atlantic because the presently available data are inconsistent with the plate geometry assumed in deriving RM1. It is demonstrated that this inconsistency can be remedied by postulating the existence of internal deformation with the Indian plate, although alternate explanations are possible.

  9. Plate tectonics, damage and inheritance

    NASA Astrophysics Data System (ADS)

    Bercovici, D. A.; Ricard, Y. R.

    2013-12-01

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto subduction about 4Ga, evident in geochemical analysis from ancient cratons, to global tectonics by 3-2.7Ga, suggests that plates and plate boundaries spread globally over a 1Gyr period. We hypothesize that when sufficient lithospheric damage, which promotes shear-localization and long-lived weak zones, combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of plate boundaries and eventually fully formed tectonic plates driven by subduction alone. We demonstrate this process with an idealized model of pressure-driven flow (wherein a low pressure zone is equivalent to downwelling suction or slab pull) in a lithosphere that self-weakens according to a mylonitic-type polycrystalline grain-damage mechanism (Bercovici and Ricard, Phys. Earth Planet. Int. v.202-203, pp27-55, 2012). In the simplest case, for Earth-like conditions, four successive orthogonal rotations of the driving pressure field yield relic damage zones that are inherited to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even as flow is only driven by subduction. For Venus' hotter surface conditions, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which is compatible with observations. After plates are developed, continued changes in driving forces combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor and micro plates.

  10. Sub-Plate Overlap Code Documentation

    NASA Technical Reports Server (NTRS)

    Taff, L. G.; Bucciarelli, B.; Zarate, N.

    1997-01-01

    An expansion of the plate overlap method of astrometric data reduction to a single plate has been proposed and successfully tested. Each plate is (artificially) divided into sub-plates which can then be overlapped. This reduces the area of a 'plate' over which a plate model needs to accurately represent the relationship between measured coordinates and standard coordinates. Application is made to non-astrographic plates such as Schmidt plates and to wide-field astrographic plates. Indeed, the method is completely general and can be applied to any type of recording media.

  11. Solving Equations of Multibody Dynamics

    NASA Technical Reports Server (NTRS)

    Jain, Abhinandan; Lim, Christopher

    2007-01-01

    Darts++ is a computer program for solving the equations of motion of a multibody system or of a multibody model of a dynamic system. It is intended especially for use in dynamical simulations performed in designing and analyzing, and developing software for the control of, complex mechanical systems. Darts++ is based on the Spatial-Operator- Algebra formulation for multibody dynamics. This software reads a description of a multibody system from a model data file, then constructs and implements an efficient algorithm that solves the dynamical equations of the system. The efficiency and, hence, the computational speed is sufficient to make Darts++ suitable for use in realtime closed-loop simulations. Darts++ features an object-oriented software architecture that enables reconfiguration of system topology at run time; in contrast, in related prior software, system topology is fixed during initialization. Darts++ provides an interface to scripting languages, including Tcl and Python, that enable the user to configure and interact with simulation objects at run time.

  12. From seismic images to plate dynamics: Towards the full inverse

    NASA Astrophysics Data System (ADS)

    Gurnis, M.; Ratnaswamy, V.; Stadler, G.; Ghattas, O.; Alisic, L.

    2014-12-01

    Three-dimensional seismic images of slabs and other mantle structures provide a first order constraint on the forces driving plate motions. Previous attempts to invert for plate motions from seismic images have blurry slabs that do not act as stress guides. Using forward models, we describe characteristics needed to capture the coupling between mantle structures and plates. In forward models, we capitalized on advances in adaptive mesh refinement and scalable solvers to simulate global mantle flow and plate motions, with plate margins resolved down to 1 km. Cold thermal anomalies within the lower mantle are coupled into oceanic plates through narrow high-viscosity slabs, altering the velocity of oceanic plates. Back-arc extension and slab rollback are emergent consequences of slab descent in the upper mantle. The forward models require the solution of a highly ill-conditioned non-linear Stokes equation. Based on a realistic rheological model with yielding and strain rate weakening from dislocation creep, we formulate inverse problems casted as PDE-constrained optimization problems and derive adjoints of the nonlinear Stokes and incompressibility equations. An inexact-Gauss Newton method is used to infer the rheological parameters while quantifying the uncertainty using the Hessian at the maximum a posteriori (MAP) point. Through 2-D numerical experiments we demonstrate that when the temperature field is known from seismic images, we can recover all of these properties to varying levels of certainty: strength of plate boundaries, yield stress and strain rate exponent in the upper mantle. When the system becomes more unconstrained (when all three mechanical properties are unknown), there can be tradeoffs depending on how well the data approximates the realistic dynamics. As plate boundaries become weaker beyond a limiting value, the uncertainty of the inferred parameters increases due to insensitivity of plate motion to plate coupling. Using the inverse of the

  13. Gravity and Flexure Modelling of Subducting Plates

    NASA Astrophysics Data System (ADS)

    Hunter, J. A.; Watts, A. B.; SO 215 Shipboard Scientific Party

    2012-04-01

    The long-term strength of the lithosphere is determined by its flexural rigidity, which is commonly expressed through the effective elastic thickness, Te. Flexure studies have revealed a dependence of Te on thermal age. In the oceans, loads formed on young (70 Ma) seafloor. In the continents, loads on young (1000 Ma) lithosphere. Recent studies have questioned the relationship of Te with age, especially at subduction zones, where oceanic and continental lithosphere are flexed downwards by up to ~6 km over horizontal distances of up to ~350 km. We have therefore used free-air gravity anomaly and topography profile data, combined with forward and inverse modelling techniques, to re-assess Te in these settings. Preliminary inverse modelling results from the Tonga-Kermadec Trench - Outer Rise system, where the Pacific plate is subducting beneath the Indo-Australian plate, show large spatial variations in Te that are unrelated to age. In contrast to the southern end of the system, where Te is determined by the depth to the 600° C and 900° C isotherms, the northern end of the system shows a reduction in strength. Results also suggest a reduction in Te trenchward of the outer rise that is coincident with a region of pervasive extensional faulting visible in swath bathymetry data. In a continental setting, the Ganges foreland basin has formed by flexure of the Indo-Australian plate in front of the migrating loads of the Himalaya. Preliminary forward modelling results, using the Himalaya as a known surface topographic load, suggest that Te is high - consistent with the great age of Indian cratonic lithosphere. However, results from inverse modelling that solves for unknown loads (vertical shear force and bending moment) show significant scatter and display trade-offs between Te and these driving loads.

  14. Stresses in adhesively bonded joints: A closed form solution. [plate theory

    NASA Technical Reports Server (NTRS)

    Delale, F.; Erdogan, F.; Aydinoglu, M. N.

    1980-01-01

    The plane strain of adhesively bonded structures which consist of two different orthotropic adherents is considered. Assuming that the thicknesses of the adherends are constant and are small in relation to the lateral dimensions of the bonded region, the adherends are treated as plates. The transverse shear effects in the adherends and the in-plane normal strain in the adhesive are taken into account. The problem is reduced to a system of differential equations for the adhesive stresses which is solved in closed form. A single lap joint and a stiffened plate under various loading conditions are considered as examples. To verify the basic trend of the solutions obtained from the plate theory a sample problem is solved by using the finite element method and by treating the adherends and the adhesive as elastic continua. The plate theory not only predicts the correct trend for the adhesive stresses but also gives rather surprisingly accurate results.

  15. Three-dimensional elasticity solution of an infinite plate with a circular hole

    NASA Technical Reports Server (NTRS)

    Delale, F.; Erdogan, F.

    1982-01-01

    The elasticity problem for a thick plate with a circular hole is formulated in a systematic fashion by using the z-component of the Galerkin vector and that of Muki's harmonic vector function. The problem was originally solved by Alblas. The reasons for reconsidering it are to develop a technique which may be used in solving the elasticity problem for a multilayered plate and to verify and extend the results given by Alblas. The problem is reduced to an infinite system of algebraic equations which is solved by the method of reduction. Various stress components are tabulated as functions of a/h, z/h, r/a, and nu, a and 2h being the radius of the hole and the plate thickness and nu, the Poisson's ratio. The significant effect of the Poisson's ratio on the behavior and the magnitude of the stresses is discussed.

  16. Mantle convection with plates and mobile, faulted plate margins.

    PubMed

    Zhong, S; Gurnis, M

    1995-02-10

    A finite-element formulation of faults has been incorporated into time-dependent models of mantle convection with realistic rheology, continents, and phase changes. Realistic tectonic plates naturally form with self-consistent coupling between plate and mantle dynamics. After the initiation of subduction, trenches rapidly roll back with subducted slabs temporarily laid out along the base of the transition zone. After the slabs have penetrated into the lower mantle, the velocity of trench migration decreases markedly. The inhibition of slab penetration into the lower mantle by the 670-kilometer phase change is greatly reduced in these models as compared to models without tectonic plates. PMID:17813909

  17. Stress measurement in thick plates using nonlinear ultrasonics

    SciTech Connect

    Abbasi, Zeynab E-mail: dozevin@uic.edu; Ozevin, Didem E-mail: dozevin@uic.edu

    2015-03-31

    In this paper the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded thick steel plates using fundamental theory of nonlinear ultrasonics is investigated in order to measure the stress state at a given cross section. The measurement concept is based on phased array placement of ultrasonic transmitter-receiver to scan three angles of a given cross section using Rayleigh waves. The change in the ultrasonic data in thick steel plates is influenced by normal and shear stresses; therefore, three measurements are needed to solve the equations simultaneously. Different thickness plates are studied in order to understand the interaction of Rayleigh wave penetration depth and shear stress. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The influences of plate thickness and ultrasonic frequency on the identification of stress tensor are numerically studied in 3D structural geometry and Murnaghan material model. The experimental component of this study includes uniaxial loading of the plate while measuring ultrasonic wave at three directions (perpendicular, parallel and angled to the loading direction). Instead of rotating transmitter-receiver pair for each test, a device capable of measuring the three angles is designed.

  18. Theoretical-experimental method of determining the drag coefficient of a harmonically oscillating thin plate

    NASA Astrophysics Data System (ADS)

    Egorov, A. G.; Kamalutdinov, A. M.; Paimushin, V. N.; Firsov, V. A.

    2016-03-01

    A method for determining the drag coefficient of a thin plate harmonically oscillating in a viscous incompressible fluid is proposed. The method is based on measuring the amplitude of deflections of cantilever-fixed thin plates exhibiting damping flexural oscillations with a frequency corresponding to the first mode and on solving an inverse problem of calculating the drag coefficient on the basis of the experimentally found logarithmic decrement of beam oscillations.

  19. Difficulties encountered removing locked plates

    PubMed Central

    Raja, S; Imbuldeniya, AM; S, Garg; Groom, G

    2012-01-01

    INTRODUCTION Locked plates are commonly used to obtain fixation in periarticular and comminuted fractures. Their use has also gained popularity in repairing fractures in osteoporotic bone. These plates provide stable fixation and promote biological healing. Over the last 3 years, we have used over 150 locked plates with varying success to fix periarticular fractures involving mainly the knee and ankle. In this study, we report our clinical experience and the difficulties encountered when removing locked plates in adult patients with a variety of indications including implant failure, infection, non-union and a palpable symptomatic implant. METHODS A retrospective analysis was performed of patients enrolled prospectively into a database. Included in the study were 36 consecutive adult patients who each underwent the procedure of locked plate removal in a single inner city level 1 trauma centre. Data collected included primary indication for fixation, indication for implant removal, time of the implant in situ, grade of operating surgeon and difficulties encountered during the procedure. RESULTS Implant removal was associated with a complication rate of 47%. The major problems encountered were difficulty in removing the locked screws and the implant itself. A total of ten cold welded screws were found in eight cases. Removal was facilitated by high speed metal cutting burrs and screw removal sets in all but one case, where a decision was made to leave the plate in situ. CONCLUSIONS The majority of studies investigating implant removal and problems encountered in doing so report a relatively high complication rate. With the advent of locking plates and their growing popularity, difficulties are now being seen intra-operatively when removing them. There is a paucity of data, however, specifically directed at locking plate removal. We recommend that surgeons should be aware of the potential complications while removing locked plates. Fluoroscopic control and all

  20. SOLV-DB: Solvents Data

    DOE Data Explorer

    SOLV-DB provides a specialized mix of information on commercially available solvents. The development of the database was funded under the Strategic Environmental Research and Development Program (SERDP) with funds from EPA and DOE's Office of Industrial Technologies in EE. The information includes: • Health and safety considerations involved in choosing and using solvents • Chemical and physical data affecting the suitability of a particular solvent for a wide range of potential applications • Regulatory responsibilities, including exposure and effluent limits, hazard classification status with respect to several key statutes, and selected reporting requirements • Environmental fate data, to indicate whether a solvent is likely to break down or persist in air or water, and what types of waste treatment techniques may apply to it • CAS numbers (from Chemical Abstracts Service) and Sax Numbers (from Sax, et.al., Dangerous Properties of Industrial Materials) Supplier Information See help information at http://solvdb.ncms.org/welcome.htm (Specialized Interface)

  1. Solving the structure of metakaolin

    SciTech Connect

    Proffen, Thomas E; White, Claire E; Provis, John L; Riley, Daniel P; Van Deventer, Jannie S J

    2009-01-01

    Metakaolin has been used extensively as a cement additive and paint extender, and recently as a geopolymer precursor. This disordered layered aluminosilicate is formed via the dehydroxylation of kaolinite. However, an accurate representation of its atomic structure has bever before been presented. Here, a novel synergy between total scattering and density functional modeling is presented to solve the structure of metakaolin. The metastable structure is elucidated by iterating between least-squares real-space refinement using neutron pair distribution function data, and geometry optimization using density functional modeling. The resulting structural representation is both energetically feasible and in excellent agreement with experimental data. This accurate structure of metakaolin provides new insight into the local environment of the aluminum atoms, with evidence of the existence of tri-coordinated aluminum. By the availability of this detailed atomic description, there exists the opportunity to tailor chemical and mechanical processes involving metakaolin at the atomic level to obtain optimal performance at the macro-scale.

  2. High loading uranium fuel plate

    DOEpatents

    Wiencek, Thomas C.; Domagala, Robert F.; Thresh, Henry R.

    1990-01-01

    Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pair of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat having a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process.

  3. Trapping of surface gravity waves by a vertical flexible porous plate near a wall

    NASA Astrophysics Data System (ADS)

    Kaligatla, R. B.; Koley, S.; Sahoo, T.

    2015-10-01

    The present study deals with the trapping of oblique surface gravity waves by a vertical submerged flexible porous plate located near a rigid wall in water of finite as well as infinite depths. The physical problem is based on the assumption of small amplitude water wave theory and structural response. The flexible plate is assumed to be thin and is modeled based on the Euler-Bernoulli beam equation. Using the Green's function technique to the plate equation and associated boundary conditions, an integral equation is derived which relates the normal velocity on the plate to the difference in velocity potentials across the plate involving the porous-effect parameter and structural rigidity. Further, applying Green's second identity to the free-surface Green's function and the scattered velocity potentials on the two sides of the plate, a system of three more integral equations is derived involving the velocity potentials and their normal derivatives across the plate boundary along with the velocity potential on the rigid wall. The system of integral equations is converted into a set of algebraic equations using appropriate Gauss quadrature formula which in turn solved to obtain various quantities of physical interest. Utilizing Green's identity, explicit expressions for the reflection coefficients are derived in terms of the velocity potentials and their normal derivatives across the plate. Energy balance relations are derived and used to check the accuracy of the computational results. As special cases of the submerged plate, wave trapping by the bottom-standing as well as surface-piercing plates is analyzed. Effects of various wave and structural parameters in trapping of surface waves are studied from the computational results by analyzing the reflection coefficients, wave forces exerted on the plate and the rigid wall, flow velocity, plate deflections and surface elevations. It is observed that surface-piercing plate is more effective for trapping of water waves

  4. Problem Solving in the General Mathematics Classroom

    ERIC Educational Resources Information Center

    Troutman, Andria Price; Lichtenberg, Betty Plunkett

    1974-01-01

    Five steps common to different problem solving models are listed. Next, seven specific abilities related to solving problems are discussed and examples given. Sample activities, appropriate to help in developing these specific abilities, are suggested. (LS)

  5. The Important Thing about Teaching Problem Solving

    ERIC Educational Resources Information Center

    Roberts, Sally K.

    2010-01-01

    The author teaches a content course in problem solving for middle school teachers. During the course, teacher candidates have the opportunity to confront their insecurities as they actively engage in solving math problems using a variety of strategies. As the semester progresses, they add new strategies to their problem-solving arsenal and…

  6. Developing Creativity through Collaborative Problem Solving

    ERIC Educational Resources Information Center

    Albert, Lillie R.; Kim, Rina

    2013-01-01

    This paper discusses an alternative approach for developing problem solving experiences for students. The major argument is that students can develop their creativity by engaging in collaborative problem solving activities in which they apply a variety of mathematical methods creatively to solve problems. The argument is supported by: considering…

  7. Problem Solving Appraisal of Delinquent Adolescents.

    ERIC Educational Resources Information Center

    Perez, Ruperto M.; And Others

    The study investigated the following: (1) the relationship of problem solving appraisal to narcissistic vulnerability, locus of control, and depression; (2) the differences in problem solving appraisal, locus of control, and depression in first-time and repeat offenders; and (3) the prediction of problem solving appraisal by narcissistic…

  8. Disciplinary Foundations for Solving Interdisciplinary Scientific Problems

    ERIC Educational Resources Information Center

    Zhang, Dongmei; Shen, Ji

    2015-01-01

    Problem-solving has been one of the major strands in science education research. But much of the problem-solving research has been conducted on discipline-based contexts; little research has been done on how students, especially individuals, solve interdisciplinary problems. To understand how individuals reason about interdisciplinary problems, we…

  9. Theoretical and Philosophical Perspectives to Problem Solving.

    ERIC Educational Resources Information Center

    Sherman, Thomas M.; And Others

    1988-01-01

    Five articles explore various theoretical aspects of problems and problem solving skills. Highlights include strategies to learn problem solving skills; knowledge structures; metacognition; behavioral processes and cognitive psychology; erotetic logic; creativity as an aspect of computer problem solving; and programing as a problem-solving…

  10. Perspectives on Problem Solving and Instruction

    ERIC Educational Resources Information Center

    van Merrienboer, Jeroen J. G.

    2013-01-01

    Most educators claim that problem solving is important, but they take very different perspective on it and there is little agreement on how it should be taught. This article aims to sort out the different perspectives and discusses problem solving as a goal, a method, and a skill. As a goal, problem solving should not be limited to well-structured…

  11. King Oedipus and the Problem Solving Process.

    ERIC Educational Resources Information Center

    Borchardt, Donald A.

    An analysis of the problem solving process reveals at least three options: (1) finding the cause, (2) solving the problem, and (3) anticipating potential problems. These methods may be illustrated by examining "Oedipus Tyrannus," a play in which a king attempts to deal with a problem that appears to be beyond his ability to solve, and applying…

  12. Kindergarten Students Solving Mathematical Word Problems

    ERIC Educational Resources Information Center

    Johnson, Nickey Owen

    2013-01-01

    The purpose of this study was to explore problem solving with kindergarten students. This line of inquiry is highly significant given that Common Core State Standards emphasize deep, conceptual understanding in mathematics as well as problem solving in kindergarten. However, there is little research on problem solving with kindergarten students.…

  13. LEGO Robotics: An Authentic Problem Solving Tool?

    ERIC Educational Resources Information Center

    Castledine, Alanah-Rei; Chalmers, Chris

    2011-01-01

    With the current curriculum focus on correlating classroom problem solving lessons to real-world contexts, are LEGO robotics an effective problem solving tool? This present study was designed to investigate this question and to ascertain what problem solving strategies primary students engaged with when working with LEGO robotics and whether the…

  14. Collis-Romberg Mathematical Problem Solving Profiles.

    ERIC Educational Resources Information Center

    Collis, K. F.; Romberg, T. A.

    Problem solving has become a focus of mathematics programs in Australia in recent years, necessitating the assessment of students' problem-solving abilities. This manual provides a problem-solving assessment and teaching resource package containing four elements: (1) profiles assessment items; (2) profiles diagnostic forms for recording individual…

  15. Some Applications of Algebraic System Solving

    ERIC Educational Resources Information Center

    Roanes-Lozano, Eugenio

    2011-01-01

    Technology and, in particular, computer algebra systems, allows us to change both the way we teach mathematics and the mathematical curriculum. Curiously enough, unlike what happens with linear system solving, algebraic system solving is not widely known. The aim of this paper is to show that, although the theory lying behind the "exact solve"…

  16. Models of Problem Solving Processes and Abilities.

    ERIC Educational Resources Information Center

    Feldhusen, John F.; Guthrie, Virginia A.

    1979-01-01

    This paper reviews current models of problem solving to identify results relevant to teachers or instructional developers. Four areas are covered: information processing models, approaches stressing human abilities and factors, creative problem solving models, and other aspects of problem solving. Part of a theme issue on intelligence. (Author/SJL)

  17. Carbon-assisted flyer plates

    DOEpatents

    Stahl, D.B.; Paisley, D.L.

    1994-04-12

    A laser driven flyer plate is described utilizing an optical fiber connected to a laser. The end of the optical fiber has a layer of carbon and a metal layer deposited onto it. The carbon layer provides the laser induced plasma which is superior to the plasma produced from most metals. The carbon layer plasma is capable of providing a flatter flyer plate, converting more of the laser energy to driving plasma, promoting a higher flyer plate acceleration, and providing a more uniform pulse behind the plate. In another embodiment, the laser is in optical communication with a substrate onto which a layer of carbon and a layer of metal have been deposited. 2 figures.

  18. The multigap resistive plate chamber

    SciTech Connect

    Zeballos, E. Cerron; Crotty, I.; Hatzifotiadou, D.; Valverde, J. Lamas; Neupane, S.; Williams, M. C. S.; Zichichi, A.

    2015-02-03

    The paper describes the multigap resistive plate chamber (RPC). This is a variant of the wide gap RPC. However it has much improved time resolution, while keeping all the other advantages of the wide gap RPC design.

  19. Tectonics: Changing of the plates

    NASA Astrophysics Data System (ADS)

    Brandon, Alan

    2016-10-01

    The composition of Earth's crust depends on the style of plate tectonics and of the melting regimes in the mantle. Analyses of the oldest identified rocks suggest that these styles and the resulting crust have changed over Earth's history.

  20. Analytical results for post-buckling behaviour of plates in compression and in shear

    NASA Technical Reports Server (NTRS)

    Stein, M.

    1985-01-01

    The postbuckling behavior of long rectangular isotropic and orthotropic plates is determined. By assuming trigonometric functions in one direction, the nonlinear partial differential equations of von Karman large deflection plate theory are converted into nonlinear ordinary differential equations. The ordinary differential equations are solved numerically using an available boundary value problem solver which makes use of Newton's method. Results for longitudinal compression show different postbuckling behavior between isotropic and orthotropic plates. Results for shear show that change in inplane edge constraints can cause large change in postbuckling stiffness.

  1. Vibration analysis of multi-span plates having orthogonal straight edges

    NASA Astrophysics Data System (ADS)

    Liew, K. M.; Lam, K. Y.

    1991-06-01

    An accurate numerical technique is developed for flexural vibration of rectangular and L-shaped plates continuous over rigid supports with arbitrary number of spans. A set of orthogonally generated two-dimensional plates function is used in the Rayleigh-Ritz method to determine the natural frequencies of the plate systems. Several numerical examples are presented and the results obtained, where possible, are compared with the known solutions in the literature. The present method is proven to be extremely versatile in solving a broad class of the aforementioned problems.

  2. Pulse plating of nickel deposits

    SciTech Connect

    Stimetz, C.J.; Stevenson, M.F.

    1980-02-01

    Pulse plated and conventional nickel deposits have been compared for differences in morphology, mechanical properties, and microstructure. The deposits were obtained from nickel sulfamate, nickel chloride, and Watts nickel plating solutions. No significant differences were found in the direct and pulse current deposits from the sulfamate and chloride solutions; however, significant differences in microstructure, yield strength, and microhardness were observed in deposits from the Watts nickel solution.

  3. Nonlinear dynamic behavior of simply supported laminated composite plates subjected to blast load

    NASA Astrophysics Data System (ADS)

    Kazancı, Zafer; Mecitoğlu, Zahit

    2008-11-01

    This paper deals with the analysis and discussion of nonlinear dynamic response of a laminated composite plate subjected to blast load. Dynamic equations of the plate are derived by the use of the virtual work principle. The geometric nonlinearity effects are taken into account with the von Kármán large deflection theory of thin plates. Approximate solutions for a simply supported plate are assumed for the space domain. The single term approximation functions are selected by considering the nonlinear static deformations of plate, which is obtained using finite element method. The Galerkin Method is used to obtain the nonlinear differential equations in the time domain. The finite difference method is applied to solve the system of coupled nonlinear equations. The results of approximate-numerical analysis are obtained and compared with the literature and finite element results. Good agreement is found for the character and frequencies of vibrations.

  4. Dynamic analysis of tapered laminated composite magnetorheological elastomer (MRE) sandwich plates

    NASA Astrophysics Data System (ADS)

    Babu, V. Ramesh; Vasudevan, R.

    2016-03-01

    In the present study, the dynamic performance of the sandwich plate with magneto rheological elastomer (MRE) as the core layer and tapered laminated composite plates as the face layers is investigated. Various MRE tapered laminated composite sandwich plate models are formulated by dropping-off the plies longitudinally in top and bottom composite layers to yield tapered plates as the face layers and uniform MRE layer as the core layer. The governing equations of motion of tapered composite MRE sandwich plates are derived using classical laminated plate theory and solved numerically. Further, silicon based MRE is being fabricated and tested to obtain the shear and loss moduli using MR rheometer. The efficacy of the finite element formulation is validated by carrying out experiments on the various prototypes of tapered composite silicon based MRE sandwich plates and comparing the results in terms of natural frequencies obtained at various magnetic fields with those obtained numerically and with available literature. Also, the effects of magnetic field, taper angle of the top and bottom layers, aspect ratio, ply orientations and various end conditions on the various dynamic properties of tapered laminated composite MRE sandwich plate are investigated. Further, the transverse vibration responses of three different tapered composite MRE based sandwich plates under harmonic force excitation are analyzed at various magnetic fields.

  5. Solving equations through particle dynamics

    NASA Astrophysics Data System (ADS)

    Edvardsson, S.; Neuman, M.; Edström, P.; Olin, H.

    2015-12-01

    The present work evaluates a recently developed particle method (DFPM). The basic idea behind this method is to utilize a Newtonian system of interacting particles that through dissipation solves mathematical problems. We find that this second order dynamical system results in an algorithm that is among the best methods known. The present work studies large systems of linear equations. Of special interest is the wide eigenvalue spectrum. This case is common as the discretization of the continuous problem becomes dense. The convergence rate of DFPM is shown to be in parity with that of the conjugate gradient method, both analytically and through numerical examples. However, an advantage with DFPM is that it is cheaper per iteration. Another advantage is that it is not restricted to symmetric matrices only, as is the case for the conjugate gradient method. The convergence properties of DFPM are shown to be superior to the closely related approach utilizing only a first order dynamical system, and also to several other iterative methods in numerical linear algebra. The performance properties are understood and optimized by taking advantage of critically damped oscillators in classical mechanics. Just as in the case of the conjugate gradient method, a limitation is that all eigenvalues (spring constants) are required to be of the same sign. DFPM has no other limitation such as matrix structure or a spectral radius as is common among iterative methods. Examples are provided to test the particle algorithm's merits and also various performance comparisons with existent numerical algorithms are provided.

  6. Community-powered problem solving.

    PubMed

    Gouillart, Francis; Billings, Douglas

    2013-04-01

    Traditionally, companies have managed their constituencies with specific processes: marketing to customers, procuring from vendors, developing HR policies for employees, and so on. The problem is, such processes focus on repeatability and compliance, so they can lead to stagnation. Inviting your constituencies to collectively help you solve problems and exploit opportunities--"co-creation"--is a better approach. It allows you to continually tap the skills and insights of huge numbers of stakeholders and develop new ways to produce value for all. The idea is to provide stakeholders with platforms (physical and digital forums) on which they can interact, get them to start exploring new experiences and connections, and let the system grow organically. A co-creation initiative by a unit of Becton, Dickinson and Company demonstrates how this works. A global leader in syringes, BD set out to deepen its ties with hospital customers and help them reduce the incidence of infections from unsafe injection and syringe disposal practices. The effort began with a cross-functional internal team, brought in the hospital procurement and supply managers BD had relationships with, and then reached out to hospitals' infection-prevention and occupational health leaders. Eventually product designers, nurses, sustainability staffers, and even hospital CFOs were using the platform, contributing data that generated new best practices and reduced infections.

  7. Community-powered problem solving.

    PubMed

    Gouillart, Francis; Billings, Douglas

    2013-04-01

    Traditionally, companies have managed their constituencies with specific processes: marketing to customers, procuring from vendors, developing HR policies for employees, and so on. The problem is, such processes focus on repeatability and compliance, so they can lead to stagnation. Inviting your constituencies to collectively help you solve problems and exploit opportunities--"co-creation"--is a better approach. It allows you to continually tap the skills and insights of huge numbers of stakeholders and develop new ways to produce value for all. The idea is to provide stakeholders with platforms (physical and digital forums) on which they can interact, get them to start exploring new experiences and connections, and let the system grow organically. A co-creation initiative by a unit of Becton, Dickinson and Company demonstrates how this works. A global leader in syringes, BD set out to deepen its ties with hospital customers and help them reduce the incidence of infections from unsafe injection and syringe disposal practices. The effort began with a cross-functional internal team, brought in the hospital procurement and supply managers BD had relationships with, and then reached out to hospitals' infection-prevention and occupational health leaders. Eventually product designers, nurses, sustainability staffers, and even hospital CFOs were using the platform, contributing data that generated new best practices and reduced infections. PMID:23593769

  8. How mantle slabs drive plate tectonics.

    PubMed

    Conrad, Clinton P; Lithgow-Bertelloni, Carolina

    2002-10-01

    The gravitational pull of subducted slabs is thought to drive the motions of Earth's tectonic plates, but the coupling between slabs and plates is not well established. If a slab is mechanically attached to a subducting plate, it can exert a direct pull on the plate. Alternatively, a detached slab may drive a plate by exciting flow in the mantle that exerts a shear traction on the base of the plate. From the geologic history of subduction, we estimated the relative importance of "pull" versus "suction" for the present-day plates. Observed plate motions are best predicted if slabs in the upper mantle are attached to plates and generate slab pull forces that account for about half of the total driving force on plates. Slabs in the lower mantle are supported by viscous mantle forces and drive plates through slab suction. PMID:12364804

  9. How mantle slabs drive plate tectonics.

    PubMed

    Conrad, Clinton P; Lithgow-Bertelloni, Carolina

    2002-10-01

    The gravitational pull of subducted slabs is thought to drive the motions of Earth's tectonic plates, but the coupling between slabs and plates is not well established. If a slab is mechanically attached to a subducting plate, it can exert a direct pull on the plate. Alternatively, a detached slab may drive a plate by exciting flow in the mantle that exerts a shear traction on the base of the plate. From the geologic history of subduction, we estimated the relative importance of "pull" versus "suction" for the present-day plates. Observed plate motions are best predicted if slabs in the upper mantle are attached to plates and generate slab pull forces that account for about half of the total driving force on plates. Slabs in the lower mantle are supported by viscous mantle forces and drive plates through slab suction.

  10. Geometry of the Cocos Plate Under North American Plate

    NASA Astrophysics Data System (ADS)

    Perez-Campos, X.

    2015-12-01

    The Cocos plate subducts under the North American plate with a complex geometry, and previous seismicity studies revealed some of this complexity. However, details of the geometry and the depth that the plate penetrates werelargely unknown. Since 2004, temporary experiments and the expansion of the permanent network of the Servicio Sismológico Nacional (SSN, Mexican National Seismological Service) have improved resolution of the plate geometry and have helped to map its descent into the upper mantle. Going from northwest to southeast, the Cocos plate appears to be fragmenting into north and south segments. The north segment subducts with an angle of ~30º and the south with an angle of ~10-15º. The transition is smooth near the trench and progresses to a tear at depth; this coincides with the projection of the Orozco Fracture Zone to depth. Also, this transition marks the limit of the presence to the south of an ultra slow velocity layer (USL) on top of the slab.South of this transition, the Cocos plate subducts horizontally , underplating the North American plate for a distance of ~140 to ~300 km from the trench. Along this horizontal region, silent slow events (SSE) and tectonic tremor (TT) have been observed. At a distance of 300 km from the trench (beneath central Mexico), the plate dives into the mantle with an angle of 76º to a depth of 500 km. This geometry changes abruptly to the south, marking the eastern limit of the USL. This change seems to be also characterized by a tear on the slab. Finally to the south, the Cocos plate subducts with a constant angle of 26º. This presentation summarizes the work of many contributors including A. Arciniega-Ceballos, M. Brudzinski, E. Cabral-Cano, T. Chen, R. Clayton,F. Cordoba-Montiel,P. Davis,S. Dougherty,F. Green, M. Gurnis, D. V. Helmberger, A. Husker,A. Iglesias, Y. Kim, V. Manea, D. Melgar, M. Rodríguez-Domínguez,S. K. Singh, T.-R. A. Song, C. M. Valdés-González, D. Valencia-Cabrera

  11. Plate mode velocities in graphite/epoxy plates

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Gorman, M. R.

    1994-01-01

    Measurements of the velocities of the extensional and flexural plate modes were made along three directions of propagation in four graphite/epoxy composite plates. The acoustic signals were generated by simulated acoustic emission events (pencil lead breaks or Hsu-Neilson sources) and detected by by broadband ultrasonic transducers. The first arrival of the extensional plate mode, which is nondispersive at low frequencies, was measured at a number of different distances from the source along the propagation direction of interest. The velocity was determined by plotting the distance versus arrival time and computing its slope. Because of the large dispersion of the flexural mode, a Fourier phase velocity technique was used to characterize this mode. The velocity was measured up to a frequency of 160 kHz. Theoretical predictions of the velocities of these modes were also made and compared with experimental observations. Classical plate theory yields good agreement with the measured extensional velocities. For predictions of the dispersion of the flexural mode, Mindlin plates theory, which includes the effects of shear deformation and rotatory inertia was shown to give better agreement with the experimental measurements.

  12. Vibro-acoustic response and sound transmission loss analysis of functionally graded plates

    NASA Astrophysics Data System (ADS)

    Chandra, N.; Raja, S.; Nagendra Gopal, K. V.

    2014-10-01

    This paper presents analytical studies on the vibro-acoustic and sound transmission loss characteristics of functionally graded material (FGM) plates using a simple first-order shear deformation theory. The material properties of the plate are assumed to vary according to power law distribution of the constituent materials in terms of volume fraction. The sound radiation due to sinusoidally varying point load, uniformly distributed load and obliquely incident sound wave is computed by solving the Rayleigh integral with a primitive numerical scheme. Displacement, velocity, acceleration, radiated sound power level, radiated sound pressure level and radiation efficiency of FGM plate for varying power law index are examined. The sound transmission loss of the FGM plate for several incidence angles and varying power law index is studied in detail. It has been found that, for the plate being considered, the sound power level increases monotonically with increase in power law index at lower frequency range (0-500 Hz) and a non-monotonic trend is appeared towards higher frequencies for both point and distributed force excitations. Increased vibration and acoustic response is observed for ceramic-rich FGM plate at higher frequency band; whereas a similar trend is seen for metal-rich FGM plate at lower frequency band. The dBA values are found to be decreasing with increase in power law index. The radiation efficiency of ceramic-rich FGM plate is noticed to be higher than that of metal and metal-rich FGM plates. The transmission loss below the first resonance frequency is high for ceramic-rich FGM plate and low for metal-rich FGM plate and further depends on the specific material property. The study has found that increased transmission loss can be achieved at higher frequencies with metal-rich FGM plates.

  13. An electromechanical finite element model for piezoelectric energy harvester plates

    NASA Astrophysics Data System (ADS)

    De Marqui Junior, Carlos; Erturk, Alper; Inman, Daniel J.

    2009-10-01

    Vibration-based energy harvesting has been investigated by several researchers over the last decade. The goal in this research field is to power small electronic components by converting the waste vibration energy available in their environment into electrical energy. Recent literature shows that piezoelectric transduction has received the most attention for vibration-to-electricity conversion. In practice, cantilevered beams and plates with piezoceramic layers are employed as piezoelectric energy harvesters. The existing piezoelectric energy harvester models are beam-type lumped parameter, approximate distributed parameter and analytical distributed parameter solutions. However, aspect ratios of piezoelectric energy harvesters in several cases are plate-like and predicting the power output to general (symmetric and asymmetric) excitations requires a plate-type formulation which has not been covered in the energy harvesting literature. In this paper, an electromechanically coupled finite element (FE) plate model is presented for predicting the electrical power output of piezoelectric energy harvester plates. Generalized Hamilton's principle for electroelastic bodies is reviewed and the FE model is derived based on the Kirchhoff plate assumptions as typical piezoelectric energy harvesters are thin structures. Presence of conductive electrodes is taken into account in the FE model. The predictions of the FE model are verified against the analytical solution for a unimorph cantilever and then against the experimental and analytical results of a bimorph cantilever with a tip mass reported in the literature. Finally, an optimization problem is solved where the aluminum wing spar of an unmanned air vehicle (UAV) is modified to obtain a generator spar by embedding piezoceramics for the maximum electrical power without exceeding a prescribed mass addition limit.

  14. Measurement of Kirchhoff's stress intensity factors in bending plates

    NASA Astrophysics Data System (ADS)

    Bäcker, D.; Kuna, M.; Häusler, C.

    2014-03-01

    A measurement method of the stress intensity factors defined by KIRCHHOFF's theory for a crack in a bending plate is shown. For this purpose, a thin piezoelectric polyvinylidene fluoride film (PVDF) is attached to the surface of the cracked plate. The measured electrical voltages are coupled with the load type and the crack tip position relative to the sensor film. Stress intensity factors and the crack tip position can be determined by solving the non-linear inverse problem based on the measured signals. To guarantee solvability of the problem, more measuring electrodes on the film have to be taken in to account. To the developed sensor concept the KIRCHHOFF's plate theory has been applied. In order to connect the electrical signals and the stress intensity factors the stresses near the crack tip have to be written in eigenfunctions (see WILLIAMS [1]). The presented method was verified by means of the example of a straight crack of the length 2a in an infinite isotropic plate under all- side bending. It was found that the positioning of the electrodes is delimited by two radii. On one hand, the measurement points should not be too close to the crack tip. In this area, the Kirchhoff's plate theory cannot be used effectively. On the other hand, the measuring electrodes should be placed at a smaller distance to each other and not too far from the crack tip regarding the convergence radius of the WILLIAMS series expansion. Test calculations on a straight crack in an infinite isotropic plate showed the general applicability of the measurement method.

  15. Plate tectonics of the Mediterranean region.

    PubMed

    McKenzie, D P

    1970-04-18

    The seismicity and fault plane solutions in the Mediterranean area show that two small rapidly moving plates exist in the Eastern Mediterranean, and such plates may be a common feature of contracting ocean basins. The results show that the concepts of plate tectonics apply to instantaneous motions across continental plate boundaries. PMID:16057188

  16. Electrodeposition process reduces cost of cold plates

    NASA Technical Reports Server (NTRS)

    Ruppe, E. P.

    1980-01-01

    Efficient nickel heat-exchanger cold plates can be fabricated less expensively than stainless steel plates. If adapted to mass production, it is estimated that nickel cold plates might be made for about 30 percent less than stainless-steel plates.

  17. 49 CFR 451.23 - Plate specifications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 6 2013-10-01 2013-10-01 false Plate specifications. 451.23 Section 451.23... SECURITY SAFETY APPROVAL OF CARGO CONTAINERS TESTING AND APPROVAL OF CONTAINERS Safety Approval Plate § 451.23 Plate specifications. (a) The safety approval plate must be of the size and in the...

  18. 49 CFR 451.23 - Plate specifications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 6 2012-10-01 2012-10-01 false Plate specifications. 451.23 Section 451.23... SECURITY SAFETY APPROVAL OF CARGO CONTAINERS TESTING AND APPROVAL OF CONTAINERS Safety Approval Plate § 451.23 Plate specifications. (a) The safety approval plate must be of the size and in the...

  19. Plate tectonics of the Mediterranean region.

    PubMed

    McKenzie, D P

    1970-04-18

    The seismicity and fault plane solutions in the Mediterranean area show that two small rapidly moving plates exist in the Eastern Mediterranean, and such plates may be a common feature of contracting ocean basins. The results show that the concepts of plate tectonics apply to instantaneous motions across continental plate boundaries.

  20. Beyond plate tectonics - Looking at plate deformation with space geodesy

    NASA Technical Reports Server (NTRS)

    Jordan, Thomas H.; Minster, J. Bernard

    1988-01-01

    The requirements that must be met by space-geodetic systems in order to constrain the horizontal secular motions associated with the geological deformation of the earth's surface are explored. It is suggested that in order to improve existing plate-motion models, the tangential components of relative velocities on interplate baselines must be resolved to an accuracy of less than 3 mm/yr. Results indicate that measuring the velocities between crustal blocks to + or - 5 mm/yr on 100-km to 1000-km scales can produce geologically significant constraints on the integrated deformation rates across continental plate-boundary zones such as the western United States.

  1. Plating on some difficult-to-plate metals and alloys

    SciTech Connect

    Dini, J.W.; Johnson, H.R.

    1980-02-01

    Electrodeposition of coatings on metals such as beryllium, beryllium-copper, Kovar, lead, magnesium, thorium, titanium, tungsten, uranium, zirconium, and their alloys can be problematic. This is due in most cases to a natural oxide surface film that readily reforms after being removed. The procedures we recommend for plating on these metals rely on replacing the oxide film with a displacement coating, or etching to allow mechanical keying between the substrate and plated deposit. The effectiveness of the procedures is demonstrated by interface bond strengths found in ring-shear and conical-head tensile tests.

  2. Plates for vacuum thermal fusion

    DOEpatents

    Davidson, James C.; Balch, Joseph W.

    2002-01-01

    A process for effectively bonding arbitrary size or shape substrates. The process incorporates vacuum pull down techniques to ensure uniform surface contact during the bonding process. The essence of the process for bonding substrates, such as glass, plastic, or alloys, etc., which have a moderate melting point with a gradual softening point curve, involves the application of an active vacuum source to evacuate interstices between the substrates while at the same time providing a positive force to hold the parts to be bonded in contact. This enables increasing the temperature of the bonding process to ensure that the softening point has been reached and small void areas are filled and come in contact with the opposing substrate. The process is most effective where at least one of the two plates or substrates contain channels or grooves that can be used to apply vacuum between the plates or substrates during the thermal bonding cycle. Also, it is beneficial to provide a vacuum groove or channel near the perimeter of the plates or substrates to ensure bonding of the perimeter of the plates or substrates and reduce the unbonded regions inside the interior region of the plates or substrates.

  3. Inverse problem of pulsed eddy current field of ferromagnetic plates

    NASA Astrophysics Data System (ADS)

    Chen, Xing-Le; Lei, Yin-Zhao

    2015-03-01

    To determine the wall thickness, conductivity and permeability of a ferromagnetic plate, an inverse problem is established with measured values and calculated values of time-domain induced voltage in pulsed eddy current testing on the plate. From time-domain analytical expressions of the partial derivatives of induced voltage with respect to parameters, it is deduced that the partial derivatives are approximately linearly dependent. Then the constraints of these parameters are obtained by solving a partial linear differential equation. It is indicated that only the product of conductivity and wall thickness, and the product of relative permeability and wall thickness can be determined accurately through the inverse problem with time-domain induced voltage. In the practical testing, supposing the conductivity of the ferromagnetic plate under test is a fixed value, and then the relative variation of wall thickness between two testing points can be calculated via the ratio of the corresponding inversion results of the product of conductivity and wall thickness. Finally, this method for wall thickness measurement is verified by the experiment results of a carbon steel plate. Project supported by the National Defense Basic Technology Research Program of China (Grant No. Z132013T001).

  4. Multiregional evaluation of the SimPlate heterotrophic plate count method compared to the standard plate count agar pour plate method in water.

    PubMed

    Jackson, R W; Osborne, K; Barnes, G; Jolliff, C; Zamani, D; Roll, B; Stillings, A; Herzog, D; Cannon, S; Loveland, S

    2000-01-01

    A new SimPlate heterotrophic plate count (HPC) method (IDEXX Laboratories, Westbrook, Maine) was compared with the pour plate method at 35 degrees C for 48 h. Six laboratories tested a total of 632 water samples. The SimPlate HPC method was found to be equivalent to the pour plate method by regression analysis (r = 0. 95; y = 0.99X + 0.06).

  5. Insert metering plates for gas turbine nozzles

    DOEpatents

    Burdgick, Steven S.; Itzel, Gary; Chopra, Sanjay; Abuaf, Nesim; Correia, Victor H.

    2004-05-11

    The invention comprises a metering plate which is assembled to an impingement insert for use in the nozzle of a gas turbine. The metering plate can have one or more metering holes and is used to balance the cooling flow within the nozzle. A metering plate with multiple holes reduces static pressure variations which result from the cooling airflow through the metering plate. The metering plate can be assembled to the insert before or after the insert is inserted into the nozzle.

  6. Distance Measurement Solves Astrophysical Mysteries

    NASA Astrophysics Data System (ADS)

    2003-08-01

    Location, location, and location. The old real-estate adage about what's really important proved applicable to astrophysics as astronomers used the sharp radio "vision" of the National Science Foundation's Very Long Baseline Array (VLBA) to pinpoint the distance to a pulsar. Their accurate distance measurement then resolved a dispute over the pulsar's birthplace, allowed the astronomers to determine the size of its neutron star and possibly solve a mystery about cosmic rays. "Getting an accurate distance to this pulsar gave us a real bonanza," said Walter Brisken, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. Monogem Ring The Monogem Ring, in X-Ray Image by ROSAT satellite CREDIT: Max-Planck Institute, American Astronomical Society (Click on Image for Larger Version) The pulsar, called PSR B0656+14, is in the constellation Gemini, and appears to be near the center of a circular supernova remnant that straddles Gemini and its neighboring constellation, Monoceros, and is thus called the Monogem Ring. Since pulsars are superdense, spinning neutron stars left over when a massive star explodes as a supernova, it was logical to assume that the Monogem Ring, the shell of debris from a supernova explosion, was the remnant of the blast that created the pulsar. However, astronomers using indirect methods of determining the distance to the pulsar had concluded that it was nearly 2500 light-years from Earth. On the other hand, the supernova remnant was determined to be only about 1000 light-years from Earth. It seemed unlikely that the two were related, but instead appeared nearby in the sky purely by a chance juxtaposition. Brisken and his colleagues used the VLBA to make precise measurements of the sky position of PSR B0656+14 from 2000 to 2002. They were able to detect the slight offset in the object's apparent position when viewed from opposite sides of Earth's orbit around the Sun. This effect, called parallax, provides a direct measurement of

  7. Elastoacoustic response of laminated plates

    NASA Astrophysics Data System (ADS)

    Kolar, Ramesh

    2005-04-01

    The application of composite materials in the aerospace and naval structures has increased enormously due to high specific strength and specific stiffness afforded by these materials. In this paper a formulation is developed based on Hamilton's Principle and laminated composite plate theory to study the elasto-acoustical response of composite plates under heavy fluid loadings. The formulation starts by using Hamilton's principle in conjunction with shear deformable theory of laminated composite plates. The acoustic pressure described by wave equation is computed similar to Sandman and Nelisse. Using the Rayleigh Ritz method and symbolic mathematics for evaluation of integrals, the formulation provides efficient approach for the problem defined. Typical results include radiation impedance as a function of driving frequency, vibroacoustic indicators such as radiated sound power and mean square velocity for a model problem. Such results are very important in studying constrained layer damping when viscolastic dampers are used in structural components.

  8. The Role of History-Dependent Rheology in Plate Boundary Lubrication for Generating One-Sided Subduction

    NASA Astrophysics Data System (ADS)

    Tagawa, Michio; Nakakuki, Tomoeki; Kameyama, Masanori; Tajima, Fumiko

    2007-05-01

    We have developed a two-dimensional dynamical model of asymmetric subduction integrated into the mantle convection without imposed plate velocities. In this model we consider that weak oceanic crust behaves as a lubricator on the thrust fault at the plate boundary. We introduce a rheological layer that depends on the history of the past fracture to simulate the effect of the oceanic crust. The thickness of this layer is set to be as thin as the Earth's oceanic crust. To treat 1-kilometer scale structure at the plate boundary in the 1000-kilometer scale mantle convection calculation, we introduce a new numerical method to solve the hydrodynamic equations using a couple of uniform and nonuniform grids of control volumes. Using our developed models, we have systematically investigated effects of basic rheological parameters that determine the deformation strength of the lithosphere and the oceanic crust on the development of the subducted slab, with a focus on the plate motion controlling mechanism. In our model the plate subduction is produced when the friction coefficient (0.004 0.008) of the modeled oceanic crust and the maximum strength (400 MPa) of the lithosphere are in plausible range inferred from the observations on the plate driving forces and the plate deformation, and the rheology experiments. In this range of the plate strength, yielding induces the plate bending. In this case the speed of plate motion is controlled more by viscosity layering of the underlying mantle than by the plate strength. To examine the setting of the overriding plate, we also consider the two end-member cases in which the overriding plate is fixed or freely-movable. In the case of the freely-movable overriding plate, the trench motion considerably changes the dip angle of the deep slab. Especially in the case with a shallow-angle plate boundary, retrograde slab motion occurs to generate a shallow-angle deep slab.

  9. Ionospheric plasma flow about a system of electrically biased flat plates. M.S. Thesis - Cleveland State Univ. Final Report

    NASA Technical Reports Server (NTRS)

    Herr, Joel L.

    1993-01-01

    The steady state interaction of two electrically biased parallel plates immersed in a flowing plasma characteristic of low earth orbit is studied numerically. Fluid equations are developed to describe the motion of the cold positively charged plasma ions, and are solved using finite-differences in two dimensions on a Cartesian grid. The behavior of the plasma electrons is assumed to be described by the Maxwell-Boltzmann distribution. Results are compared to an analytical and a particle simulation technique for a simplified flow geometry consisting of a single semi-infinite negatively biased plate. Comparison of the extent of the electrical disturbance into the flowing plasma and the magnitude of the current collected by the plate is very good. The interaction of two equally biased parallel plates is studied as a function of applied potential. The separation distance at which the current collected by either plate decreases by five and twenty percent is determined as a function of applied potential. The percent decreases were based on a non-interacting case. The decrease in overall current is caused by a decrease in ionic density in the region between the plates. As the separation between the plates decreases, the plates collect the ions at a faster rate than they are supplied to the middle region by the oncoming plasma flow. The docking of spacecraft in orbit is simulated by moving two plates of unequal potential toward one another in a quasi-static manner. One plate is held at a large negative potential while the other floats electrically in the resulting potential field. It is found that the floating plate does not charge continuously negative as it approaches the other more negatively biased plate. Instead, it charges more and then less negative as ionic current decreases and then increases respectively upon approach. When the two plates come into contact, it is expected that the electrically floating plate will charge rapidly negative to a potential near that of

  10. Transverse vibration of trapezoidal plates of variable thickness - Symmetric trapezoids

    NASA Astrophysics Data System (ADS)

    Liew, K. M.; Lim, M. K.

    1993-07-01

    A set of simple 2D polynomial functions is employed as the admissible displacement function in the Rayleigh-Ritz energy approach for the free transverse vibration analysis of symmetric trapezoidal plates with linearly varying thickness. The admissible function consists the product of a 2D polynomial function and a basic function defined by the product of the equations of the prescribed continuous piecewise boundary shape, each raised to the power of 0, 1 or 2 (corresponding to a free, simply supported, or clamped edge, respectively). The set of functions generated ensures the satisfaction of all the kinematic boundary conditions at the outset. The proposed method is applied to solve several symmetric trapezoidal plates with different combinations of boundary conditions and variable thickness. The results, for some cases, are compared with the available published values from the open literature. These new results may serve as benchmark data for the development of other numerical methods.

  11. Analog Processor To Solve Optimization Problems

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.; Eberhardt, Silvio P.; Thakoor, Anil P.

    1993-01-01

    Proposed analog processor solves "traveling-salesman" problem, considered paradigm of global-optimization problems involving routing or allocation of resources. Includes electronic neural network and auxiliary circuitry based partly on concepts described in "Neural-Network Processor Would Allocate Resources" (NPO-17781) and "Neural Network Solves 'Traveling-Salesman' Problem" (NPO-17807). Processor based on highly parallel computing solves problem in significantly less time.

  12. Solving global optimization problems on GPU cluster

    NASA Astrophysics Data System (ADS)

    Barkalov, Konstantin; Gergel, Victor; Lebedev, Ilya

    2016-06-01

    The paper contains the results of investigation of a parallel global optimization algorithm combined with a dimension reduction scheme. This allows solving multidimensional problems by means of reducing to data-independent subproblems with smaller dimension solved in parallel. The new element implemented in the research consists in using several graphic accelerators at different computing nodes. The paper also includes results of solving problems of well-known multiextremal test class GKLS on Lobachevsky supercomputer using tens of thousands of GPU cores.

  13. Plate-like osteoma cutis.

    PubMed

    Orme, Charisse M; Hale, Christopher S; Meehan, Shane A; Long, Wendy

    2014-12-16

    Osteoma cutis is the aberrant development of bone within the skin. The bone formation may be de novo (primary) or result from an injury to the skin (secondary). Here we present a healthy 53-year-old man with no known abnormalities in calcium or phosphate metabolism with plate-like osteoma cutis of the scalp. Plate- or plaque-like osteoma cutis was initially described as a congenital condition but has now been reported several times in the literature as an idiopathic process that occurs in adults. Treatment options are limited and are only required if the lesion is bothersome to the patient.

  14. Mobile serious games for collaborative problem solving.

    PubMed

    Sanchez, Jaime; Mendoza, Claudia; Salinas, Alvaro

    2009-01-01

    This paper presents the results obtained from the implementation of a series of learning activities based on mobile serious games (MSG) for the development of problem-solving and collaborative skills in Chilean 8th grade students. Three MSGs were developed and played by teams of four students, who had to solve the problems posed by the game collaboratively. The data shows that the experimental group had a higher perception of their own skills of collaboration and of the plan execution dimension of problem solving than the control group, providing empirical evidence regarding the contribution of MSGs to the development of collaborative problem-solving skills.

  15. Fibonacci's Triangle: A Vehicle for Problem Solving.

    ERIC Educational Resources Information Center

    Ouellette, Hugh

    1979-01-01

    A method for solving certain types of problems is illustrated by problems related to Fibonacci's triangle. The method involves pattern recognition, generalizing, algebraic manipulation, and mathematical induction. (MP)

  16. Numerical Simulation of the Turbulent Flow around a Strut Mounted on a Plate

    NASA Astrophysics Data System (ADS)

    Ungureanu, Costel; Lungu, Adrian

    2009-09-01

    The research describes the flow features around a protuberance mounted on a plate. It aims at establishing an appropriate method to further design the geometry of a fin mounted on the ship hull with the flow around the stern may be controlled. For that purpose, a numerical simulation aimed at describing the flow field around a NACA0012 hydrofoil mounted on a plate is presented. Several geometric configurations are taken into account, e.g. flat or curved plate, straight or inclined hydrofoil. RANS equations are solved to compute the solution around the juncture. Closure to the turbulence is done by using the Spalart-Allmaras one-equation model and the results are compared. A FVM technique is employed to solve the problem numerically. H-C type grids are used for the PDE discretization.

  17. Interaction between a cantilevered-free flexible plate and ideal flow

    NASA Astrophysics Data System (ADS)

    Howell, R. M.; Lucey, A. D.; Carpenter, P. W.; Pitman, M. W.

    2009-04-01

    We develop a new computational model of the linear fluid-structure interaction of a cantilevered flexible plate with an ideal flow in a channel. The system equation is solved via numerical simulations that capture transients and allow the spatial variation of the flow-structure interaction on the plate to be studied in detail. Alternatively, but neglecting wake effects, we are able to extract directly the system eigenvalues to make global predictions of the system behaviour in the infinite-time limit. We use these complementary approaches to conduct a detailed study of the fluid-structure system. When the channel walls are effectively absent, predictions of the critical velocity show good agreement with those of other published work. We elucidate the single-mode flutter mechanism that dominates the response of short plates and show that the principal region of irreversible energy transfer from fluid to structure occurs over the middle portion of the plate. A different mechanism, modal-coalescence flutter, is shown to cause the destabilisation of long plates with its energy transfer occurring closer to the trailing edge of the plate. This mechanism is shown to allow a continuous change to higher-order modes of instability as the plate length is increased. We then show how the system response is modified by the inclusion of channel walls placed symmetrically above and below the flexible plate, the effect of unsteady vorticity shed at the trailing edge of the plate, and the effect of a rigid surface placed upstream of the flexible plate. Finally, we apply the modelling techniques in a brief study of upper-airway dynamics wherein soft-palate flutter is considered to be the source of snoring noises. In doing so, we show how a time-varying mean flow influences the type of instability observed as flow speed is increased and demonstrate how localised stiffening can be used to control instability of the flexible plate.

  18. Motion transitions of falling plates via quasisteady aerodynamics.

    PubMed

    Hu, Ruifeng; Wang, Lifeng

    2014-07-01

    In this paper, we study the dynamics of freely falling plates based on the Kirchhoff equation and the quasisteady aerodynamic model. Motion transitions among fluttering, tumbling along a cusp-like trajectory, irregular, and tumbling along a straight trajectory are obtained by solving the dynamical equations. Phase diagrams spanning between the nondimensional moment of inertia and aerodynamic coefficients or aspect ratio are built to identify regimes for these falling styles. We also investigate the stability of fixed points and bifurcation scenarios. It is found that the transitions are all heteroclinic bifurcations and the influence of the fixed-point stability is local.

  19. Nonlinear dynamics and control of a vibrating rectangular plate

    NASA Technical Reports Server (NTRS)

    Shebalin, J. V.

    1983-01-01

    The von Karman equations of nonlinear elasticity are solved for the case of a vibrating rectangular plate by meams of a Fourier spectral transform method. The amplification of a particular Fourier mode by nonlinear transfer of energy is demonstrated for this conservative system. The multi-mode system is reduced to a minimal (two mode) system, retaining the qualitative features of the multi-mode system. The effect of a modal control law on the dynamics of this minimal nonlinear elastic system is examined.

  20. License Plate Recognition System for Indian Vehicles

    NASA Astrophysics Data System (ADS)

    Sanap, P. R.; Narote, S. P.

    2010-11-01

    We consider the task of recognition of Indian vehicle number plates (also called license plates or registration plates in other countries). A system for Indian number plate recognition must cope with wide variations in the appearance of the plates. Each state uses its own range of designs with font variations between the designs. Also, vehicle owners may place the plates inside glass covered frames or use plates made of nonstandard materials. These issues compound the complexity of automatic number plate recognition, making existing approaches inadequate. We have developed a system that incorporates a novel combination of image processing and artificial neural network technologies to successfully locate and read Indian vehicle number plates in digital images. Commercial application of the system is envisaged.

  1. Corrosion resistant metallic bipolar plate

    DOEpatents

    Brady, Michael P.; Schneibel, Joachim H.; Pint, Bruce A.; Maziasz, Philip J.

    2007-05-01

    A corrosion resistant, electrically conductive component such as a bipolar plate for a PEM fuel cell includes 20 55% Cr, balance base metal such as Ni, Fe, or Co, the component having thereon a substantially external, continuous layer of chromium nitride.

  2. Petroleum occurrences and plate tectonics

    SciTech Connect

    Olenin, V.B.; Sokolov, B.A.

    1983-01-01

    This paper analyzes the mechanisms of petroleum formation and petroleum accumulation proposed in recent years by some Russian and foreign investigators from the viewpoint of the new global or plate tectonics. On the basis of discussion and the facts, the authors conclude that the mechanisms proposed are in contradiction to reality and their use in practical application is at least premature.

  3. Comment on "Intermittent plate tectonics?".

    PubMed

    Korenaga, Jun

    2008-06-01

    Silver and Behn (Reports, 4 January 2008, p. 85) proposed that intermittent plate tectonics may resolve a long-standing paradox in Earth's thermal evolution. However, their analysis misses one important term, which subsequently brings their main conclusion into question. In addition, the Phanerozoic eustasy record indicates that the claimed effect of intermittency is probably weak.

  4. Troubleshooting plated-wire memories

    NASA Technical Reports Server (NTRS)

    Baker, C. M.; Bright, T. M.; Constable, R. C.

    1979-01-01

    Faults in plated wire memories are identified and located from outside of system by applying electrical impulses and analyzing their reflectance in technique of Time-Domain Reflectometry (TDR). Intermittent faults are easier to find because memory system is not disturbed by probing or disassembly.

  5. The seismotectonics of plate boundaries

    NASA Technical Reports Server (NTRS)

    Berger, J.; Brune, J. N.; Goodkind, J.; Wyatt, F.; Agnew, D. C.; Beaumont, C.

    1981-01-01

    Research on the seismotectonics of plate boundaries is summarized. Instrumental development and an observational program designed to study various aspects of the seismotectonics of southern California and the northern Gulf of California are described. A unique superconducting gravimeter was further developed and supported under this program for deployment and operation at several sites. Work on Earth tides is also discussed.

  6. Plated wire random access memories

    NASA Technical Reports Server (NTRS)

    Gouldin, L. D.

    1975-01-01

    A program was conducted to construct 4096-work by 18-bit random access, NDRO-plated wire memory units. The memory units were subjected to comprehensive functional and environmental tests at the end-item level to verify comformance with the specified requirements. A technical description of the unit is given, along with acceptance test data sheets.

  7. Double-Plate Penetration Equations

    NASA Technical Reports Server (NTRS)

    Hayashida, K. B.; Robinson, J. H.

    2000-01-01

    This report compares seven double-plate penetration predictor equations for accuracy and effectiveness of a shield design. Three of the seven are the Johnson Space Center original, modified, and new Cour-Palais equations. The other four are the Nysmith, Lundeberg-Stern-Bristow, Burch, and Wilkinson equations. These equations, except the Wilkinson equation, were derived from test results, with the velocities ranging up to 8 km/sec. Spreadsheet software calculated the projectile diameters for various velocities for the different equations. The results were plotted on projectile diameter versus velocity graphs for the expected orbital debris impact velocities ranging from 2 to 15 km/sec. The new Cour-Palais double-plate penetration equation was compared to the modified Cour-Palais single-plate penetration equation. Then the predictions from each of the seven double-plate penetration equations were compared to each other for a chosen shield design. Finally, these results from the equations were compared with test results performed at the NASA Marshall Space Flight Center. Because the different equations predict a wide range of projectile diameters at any given velocity, it is very difficult to choose the "right" prediction equation for shield configurations other than those exactly used in the equations' development. Although developed for various materials, the penetration equations alone cannot be relied upon to accurately predict the effectiveness of a shield without using hypervelocity impact tests to verify the design.

  8. Could HPS Improve Problem-Solving?

    ERIC Educational Resources Information Center

    Coelho, Ricardo Lopes

    2013-01-01

    It is generally accepted nowadays that History and Philosophy of Science (HPS) is useful in understanding scientific concepts, theories and even some experiments. Problem-solving strategies are a significant topic, since students' careers depend on their skill to solve problems. These are the reasons for addressing the question of whether problem…

  9. Solving Problems in Genetics II: Conceptual Restructuring

    ERIC Educational Resources Information Center

    Orcajo, Teresa Ibanez; Aznar, Mercedes Martinez

    2005-01-01

    This paper presents the results of part of an investigation carried out with fourth-level Spanish secondary education students (15 years old), in which we implemented a teaching unit based on problem-solving methodology as an investigation to teach genetics and human inheritance curricular contents. By solving open problems, the students…

  10. Measuring Problem Solving Skills in "Portal 2"

    ERIC Educational Resources Information Center

    Shute, Valerie J.; Wang, Lubin

    2013-01-01

    This paper examines possible improvement to problem solving skills as a function of playing the video game "Portal 2." Stealth assessment is used in the game to evaluate students' problem solving abilities--specifically basic and flexible rule application. The stealth assessment measures will be validated against commonly accepted…

  11. Problem Solving and Technology. ACESIA Monograph 2.

    ERIC Educational Resources Information Center

    Lomon, Earle L.; And Others

    1977-01-01

    The two articles dealing with problem solving and technology in this publication should be useful to those developing the kinds of materials, experiences, and thinking that elementary school industrial arts offers children. The first article accepts problem solving as an educational goal and reports a timely and universally acceptable approach.…

  12. Mathematical Problem Solving through Sequential Process Analysis

    ERIC Educational Resources Information Center

    Codina, A.; Cañadas, M. C.; Castro, E.

    2015-01-01

    Introduction: The macroscopic perspective is one of the frameworks for research on problem solving in mathematics education. Coming from this perspective, our study addresses the stages of thought in mathematical problem solving, offering an innovative approach because we apply sequential relations and global interrelations between the different…

  13. Distributed problem solving by pilots and dispatchers

    NASA Technical Reports Server (NTRS)

    Orasanu, Judith; Wich, Mike; Fischer, Ute; Jobe, Kim; Mccoy, Elaine; Beatty, Roger; Smith, Phil

    1993-01-01

    The study addressed the following question: Are flight planning problems solved differently by PILOTS and DISPATCHERS when they work alone versus when they work together? Aspect of their performance that were of interest include the following: Problem perception and definition; Problem solving strategies and information use; Options considered; Solution and rational; and errors.

  14. Problem Solving Software for Math Classes.

    ERIC Educational Resources Information Center

    Troutner, Joanne

    1987-01-01

    Described are 10 computer software programs for problem solving related to mathematics. Programs described are: (1) Box Solves Story Problems; (2) Safari Search; (3) Puzzle Tanks; (4) The King's Rule; (5) The Factory; (6) The Royal Rules; (7) The Enchanted Forest; (8) Gears; (9) The Super Factory; and (10) Creativity Unlimited. (RH)

  15. Toward a Design Theory of Problem Solving.

    ERIC Educational Resources Information Center

    Jonassen, David H.

    2000-01-01

    Proposes a metatheory of problem solving. Describes differences among problems in terms of their structured ness, domain specificity (abstractness), and complexity; describes individual differences that affect problem solving; and presents a typology of problems, each of which engages different cognitive, affective, and conative process and…

  16. Solving Cubic Equations by Polynomial Decomposition

    ERIC Educational Resources Information Center

    Kulkarni, Raghavendra G.

    2011-01-01

    Several mathematicians struggled to solve cubic equations, and in 1515 Scipione del Ferro reportedly solved the cubic while participating in a local mathematical contest, but did not bother to publish his method. Then it was Cardano (1539) who first published the solution to the general cubic equation in his book "The Great Art, or, The Rules of…

  17. New Perspectives on Human Problem Solving

    ERIC Educational Resources Information Center

    Goldstone, Robert L.; Pizlo, Zygmunt

    2009-01-01

    In November 2008 at Purdue University, the 2nd Workshop on Human Problem Solving was held. This workshop, which was a natural continuation of the first workshop devoted almost exclusively to optimization problems, addressed a wider range of topics that reflect the scope of the "Journal of Problem Solving." The workshop was attended by 35…

  18. General Description of Human Problem Solving.

    ERIC Educational Resources Information Center

    Klein, Gary A.; Weitzenfeld, Julian

    A theoretical model relating problem identification to problem solving is presented. The main purpose of the study is to increase understanding of decision making among Air Force educators. The problem-solving process is defined as the generation and evaluation of alternatives that will accomplish what is needed and the reidentification of what is…

  19. Student Modeling Based on Problem Solving Times

    ERIC Educational Resources Information Center

    Pelánek, Radek; Jarušek, Petr

    2015-01-01

    Student modeling in intelligent tutoring systems is mostly concerned with modeling correctness of students' answers. As interactive problem solving activities become increasingly common in educational systems, it is useful to focus also on timing information associated with problem solving. We argue that the focus on timing is natural for certain…

  20. Children Solving Problems. The Developing Child Series.

    ERIC Educational Resources Information Center

    Thornton, Stephanie

    The developmental increase in the ability to solve problems is a puzzle. Does it come from basic changes in mental skills, or is it a matter of practice? This book from the Developing Child series synthesizes recent research examining children's problem-solving skills development. Chapter 1 presents the major themes: (1) there is increasing…

  1. Problem Solving Interactions on Electronic Networks.

    ERIC Educational Resources Information Center

    Waugh, Michael; And Others

    Arguing that electronic networking provides a medium which is qualitatively superior to the traditional classroom for conducting certain types of problem solving exercises, this paper details the Water Problem Solving Project, which was conducted on the InterCultural Learning Network in 1985 and 1986 with students from the United States, Mexico,…

  2. Students' Equation Understanding and Solving in Iran

    ERIC Educational Resources Information Center

    Barahmand, Ali; Shahvarani, Ahmad

    2014-01-01

    The purpose of the present article is to investigate how 15-year-old Iranian students interpret the concept of equation, its solution, and studying the relation between the students' equation understanding and solving. Data from two equation-solving exercises are reported. Data analysis shows that there is a significant relationship between…

  3. Using Thinking Skills to Solve Geographic Riddles.

    ERIC Educational Resources Information Center

    Pellow, Randall A.

    1992-01-01

    Presents two geography problem-solving scenarios for use with elementary and middle school children or preservice teachers in social studies methods courses. Provides problems about the magnetic poles and the presence of ice in desert conditions. Calls upon teachers to encourage students to use their thinking skills to solve the problems. (SG)

  4. Taking "From Scratch" out of Problem Solving

    ERIC Educational Resources Information Center

    Brown, Wayne

    2007-01-01

    Solving problems and creating processes and procedures from the ground up has long been part of the IT department's way of operating. IT staffs will continue to encounter new problems to solve and new technologies to be implemented. They also must involve their constituents in the creation of solutions. Nonetheless, for many issues they no longer…

  5. Dynamic Problem Solving: A New Assessment Perspective

    ERIC Educational Resources Information Center

    Greiff, Samuel; Wustenberg, Sascha; Funke, Joachim

    2012-01-01

    This article addresses two unsolved measurement issues in dynamic problem solving (DPS) research: (a) unsystematic construction of DPS tests making a comparison of results obtained in different studies difficult and (b) use of time-intensive single tasks leading to severe reliability problems. To solve these issues, the MicroDYN approach is…

  6. The Process of Solving Complex Problems

    ERIC Educational Resources Information Center

    Fischer, Andreas; Greiff, Samuel; Funke, Joachim

    2012-01-01

    This article is about Complex Problem Solving (CPS), its history in a variety of research domains (e.g., human problem solving, expertise, decision making, and intelligence), a formal definition and a process theory of CPS applicable to the interdisciplinary field. CPS is portrayed as (a) knowledge acquisition and (b) knowledge application…

  7. A Multivariate Model of Physics Problem Solving

    ERIC Educational Resources Information Center

    Taasoobshirazi, Gita; Farley, John

    2013-01-01

    A model of expertise in physics problem solving was tested on undergraduate science, physics, and engineering majors enrolled in an introductory-level physics course. Structural equation modeling was used to test hypothesized relationships among variables linked to expertise in physics problem solving including motivation, metacognitive planning,…

  8. Teaching Effective Problem Solving Strategies for Interns

    ERIC Educational Resources Information Center

    Warren, Louis L.

    2005-01-01

    This qualitative study investigates what problem solving strategies interns learn from their clinical teachers during their internships. Twenty-four interns who completed their internship in the elementary grades shared what problem solving strategies had the greatest impact upon them in learning how to deal with problems during their internship.…

  9. Teaching and Learning through Problem Solving

    ERIC Educational Resources Information Center

    Ollerton, Mike

    2007-01-01

    In this article, the author relates some problem solving work with primary schools to Department for Children, Schools, and Families (DfES) support. In four primary schools in the West Midlands, the focus was teaching mathematics through problem solving, based on materials published on the DfES "standards" website. The author noticed the way…

  10. Parallel Algorithm Solves Coupled Differential Equations

    NASA Technical Reports Server (NTRS)

    Hayashi, A.

    1987-01-01

    Numerical methods adapted to concurrent processing. Algorithm solves set of coupled partial differential equations by numerical integration. Adapted to run on hypercube computer, algorithm separates problem into smaller problems solved concurrently. Increase in computing speed with concurrent processing over that achievable with conventional sequential processing appreciable, especially for large problems.

  11. Learning to Solve Problems in Primary Grades

    ERIC Educational Resources Information Center

    Whitin, Phyllis; Whitin, David J.

    2008-01-01

    Problem solving lies at the heart of mathematical learning. Children need opportunities to write, discuss, and solve problems on a regular basis. The problems must incorporate grade-appropriate content and be "accessible and engaging to the students, building on what they know and can do." Teachers also play a key role in establishing a classroom…

  12. Developing Legal Problem-Solving Skills.

    ERIC Educational Resources Information Center

    Nathanson, Stephen

    1994-01-01

    A law professor explains how he came to view legal problem solving as the driving concept in law school curriculum design and draws on personal experience and a survey of students concerning teaching methods in a commercial law course. He outlines six curriculum design principles for teaching legal problem solving. (MSE)

  13. Metacognition: Student Reflections on Problem Solving

    ERIC Educational Resources Information Center

    Wismath, Shelly; Orr, Doug; Good, Brandon

    2014-01-01

    Twenty-first century teaching and learning focus on the fundamental skills of critical thinking and problem solving, creativity and innovation, and collaboration and communication. Metacognition is a crucial aspect of both problem solving and critical thinking, but it is often difficult to get students to engage in authentic metacognitive…

  14. Conceptual Problem Solving in High School Physics

    ERIC Educational Resources Information Center

    Docktor, Jennifer L.; Strand, Natalie E.; Mestre, José P.; Ross, Brian H.

    2015-01-01

    Problem solving is a critical element of learning physics. However, traditional instruction often emphasizes the quantitative aspects of problem solving such as equations and mathematical procedures rather than qualitative analysis for selecting appropriate concepts and principles. This study describes the development and evaluation of an…

  15. Enigma of Runaway Stars Solved

    NASA Astrophysics Data System (ADS)

    1997-01-01

    Supernova Propels Companion Star through Interstellar Space The following success story is a classical illustration of scientific progress through concerted interplay of observation and theory. It concerns a 35-year old mystery which has now been solved by means of exciting observations of a strange double star. An added touch is the successive involvement of astronomers connected to the European Southern Observatory. For many years, astronomers have been puzzled by the fact that, among the thousands of very young, hot and heavy stars which have been observed in the Milky Way, there are some that move with exceptionally high velocities. In some cases, motions well above 100 km/sec, or ten times more than normal for such stars, have been measured. How is this possible? Which mechanism is responsible for the large amounts of energy needed to move such heavy bodies at such high speeds? Could it be that these stars are accelerated during the powerful explosion of a companion star as a supernova? Such a scenario was proposed in 1961 by Adriaan Blaauw [1], but until now, observational proof has been lacking. Now, however, strong supporting evidence for this mechanism has become available from observations obtained at the ESO La Silla observatory. The mysterious runaway stars OB-runaway stars [2] are heavy stars that travel through interstellar space with an anomalously high velocity. They have been known for several decades, but it has always been a problem to explain their high velocities. Although most OB-runaway stars are located at distances of several thousands of lightyears, their high velocity results in a measurable change in position on sky photos taken several years apart. The velocity component in the direction of the Earth can be measured very accurately from a spectrogram. From a combination of such observations, it is possible to measure the space velocity of OB-runaways. Bow shocks reveal runaway stars It has also been found that some OB-runaways display

  16. WickSolve Version 1.0

    SciTech Connect

    Andraka, Charles E.

    2011-09-27

    WickSolve is a code used to design wick structures for sodium heat pipe receivers for dish Stirling systems. WickSolve can model distributed pore size wicks in domes and cylinders, and interfaces with CIRCE2, another Sandia code, to determine flux boundary conditions to the wick. WickSolve is available as an executable for Windows computer systems. Wicksolve is used for design of wick structures for high temperature sodium heat pipes for solar applications. These wick structures may contain a distribution of pore sizes (felt metal, sintered metal powders, etc) to enhance heat transfer by allowing partial wick dryout. WickSolve incorporates a 2-D liquid flow model (finite differencing) to model in-plane liquid flow, and a 1-D vapor flow finite difference model for vapor flow perpendicular to the liquid flow surface. The models are coupled by the liquid void fraction in the wick, and solved iteratively.

  17. WickSolve Version 1.0

    2011-09-27

    WickSolve is a code used to design wick structures for sodium heat pipe receivers for dish Stirling systems. WickSolve can model distributed pore size wicks in domes and cylinders, and interfaces with CIRCE2, another Sandia code, to determine flux boundary conditions to the wick. WickSolve is available as an executable for Windows computer systems. Wicksolve is used for design of wick structures for high temperature sodium heat pipes for solar applications. These wick structures maymore » contain a distribution of pore sizes (felt metal, sintered metal powders, etc) to enhance heat transfer by allowing partial wick dryout. WickSolve incorporates a 2-D liquid flow model (finite differencing) to model in-plane liquid flow, and a 1-D vapor flow finite difference model for vapor flow perpendicular to the liquid flow surface. The models are coupled by the liquid void fraction in the wick, and solved iteratively.« less

  18. Consecutive plate acoustic suppressor apparatus and methods

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph (Inventor); Parrott, Tony (Inventor)

    1992-01-01

    An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing, arrangement, etc., can be selected to achieve bulk material-like behavior.

  19. Consecutive Plate Acoustic Suppressor Apparatus and Methods

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph (Inventor); Parrott, Tony L. (Inventor)

    1993-01-01

    An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing, arrangement, etc., can be selected to achieve bulk material-like behavior.

  20. Avionics Box Cold Plate Damage Prevention

    NASA Technical Reports Server (NTRS)

    Stambolian, Damon B.; Larchar, Steven W.; Henderson, Gena; Tran, Donald; Barth, Tim

    2012-01-01

    Problem Introduction: 1. Prevent Cold Plate Damage in Space Shuttle. 1a. The number of cold plate problems had increased from an average of 16.5 per/year between 1990 through 2000, to an average of 39.6 per year between 2001through 2005. 1b. Each complete set of 80 cold plates cost approximately $29 million, an average of $362,500 per cold plate. 1c It takes four months to produce a single cold plate. 2. Prevent Cold Plate Damage in Future Space Vehicles.

  1. Evaluation of an automated agar plate streaker.

    PubMed Central

    Tilton, R C; Ryan, R W

    1978-01-01

    An automated agar plate streaker was evaluated. The Autostreaker mechanizes the agar plate streaking process by providing storage for plates, labeling and streaking one or more plates for either isolation or quantitation, and stacking in one of several racks for subsequent incubation. Results showed the Autostreaker to produce agar plates with well-separated colonies and accurate colony counts. A total of 1,930 clinical specimens were processed either in parallel with manual methods or solely by the Autostreaker. Technologist acceptance of machine-streaked plates was outstanding. Images PMID:348722

  2. Cryo-EM single particle analysis with the Volta phase plate.

    PubMed

    Danev, Radostin; Baumeister, Wolfgang

    2016-01-01

    We present a method for in-focus data acquisition with a phase plate that enables near-atomic resolution single particle reconstructions. Accurate focusing is the determining factor for obtaining high quality data. A double-area focusing strategy was implemented in order to achieve the required precision. With this approach we obtained a 3.2 Å resolution reconstruction of the Thermoplasma acidophilum 20S proteasome. The phase plate matches or slightly exceeds the performance of the conventional defocus approach. Spherical aberration becomes a limiting factor for achieving resolutions below 3 Å with in-focus phase plate images. The phase plate could enable single particle analysis of challenging samples in terms of small size, heterogeneity and flexibility that are difficult to solve by the conventional defocus approach.

  3. Buckling and Vibration of Fiber Reinforced Composite Plates With Nanofiber Reinforced Matrices

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.; Murthy, Pappu L. N.

    2011-01-01

    Anisotropic composite plates were evaluated with nanofiber reinforced matrices (NFRM). The nanofiber reinforcement volumes ratio in the matrix was 0.01. The plate dimensions were 20 by 10 by 1.0 in. (508 by 254 by 25.4 mm). Seven different loading condition cases were evaluated for buckling: three for uniaxial loading, three for pairs of combined loading, and one with three combined loadings. The anisotropy arose from the unidirectional plates having been at 30 from the structural axis. The anisotropy had a full 6 by 6 rigidities matrix which were satisfied and solved by a Galerkin buckling algorithm. For vibration the same conditions were used with the applied cods about a small fraction of the buckling loads. The buckling and vibration results showed that the NFRM plates buckled at about twice those with conventional matrix.

  4. Approximate study of the free vibrations of a cantilever anisotropic plate carrying a concentrated mass

    NASA Astrophysics Data System (ADS)

    Ciancio, P. M.; Rossit, C. A.; Laura, P. A. A.

    2007-05-01

    This study is concerned with the vibration analysis of a cantilevered rectangular anisotropic plate when a concentrated mass is rigidly attached to its center point. Based on the classical theory of anisotropic plates, the Ritz method is employed to perform the analysis. The deflection of the plate is approximated by a set of beam functions in each principal coordinate direction. The influence of the mass magnitude on the natural frequencies and modal shapes of vibration is studied for a boron-epoxy plate and also in the case of a generic anisotropic material. The classical Ritz method with beam functions as the spatial approximation proved to be a suitable procedure to solve a problem of this analytical complexity.

  5. Vibration analysis of twisted plates using first order shear deformation theory

    NASA Astrophysics Data System (ADS)

    Hu, X. X.; Sakiyama, T.; Xiong, Y.; Matsuda, H.; Morita, C.

    2004-10-01

    Based on general shell theory and the first order shear deformation theory, an accurate relationship between strains and displacements of a twisted plate is derived by the Green strain tensor. An equation of equilibrium for free vibration is given by the principle of virtual work and the governing equation is solved by using the Rayleigh-Ritz method with sets of orthonormal polynomials in which only the first polynomials are defined according to the geometric boundary conditions of a plate and the others are generated by the Gram-Schmidt process. The numerical verification is carried out by comparing with previous results of cantilever plates. Vibration characteristics of cantilever twisted plates such as frequency parameters and corresponding mode shapes are obtained by the present numerical method, and the effects of the twist angle, the aspect ratio and the thickness ratio on them are studied.

  6. Cryo-EM single particle analysis with the Volta phase plate

    PubMed Central

    Danev, Radostin; Baumeister, Wolfgang

    2016-01-01

    We present a method for in-focus data acquisition with a phase plate that enables near-atomic resolution single particle reconstructions. Accurate focusing is the determining factor for obtaining high quality data. A double-area focusing strategy was implemented in order to achieve the required precision. With this approach we obtained a 3.2 Å resolution reconstruction of the Thermoplasma acidophilum 20S proteasome. The phase plate matches or slightly exceeds the performance of the conventional defocus approach. Spherical aberration becomes a limiting factor for achieving resolutions below 3 Å with in-focus phase plate images. The phase plate could enable single particle analysis of challenging samples in terms of small size, heterogeneity and flexibility that are difficult to solve by the conventional defocus approach. DOI: http://dx.doi.org/10.7554/eLife.13046.001 PMID:26949259

  7. Synthesizing Huber's Problem Solving and Kolb's Learning Cycle: A Balanced Approach to Technical Problem Solving

    ERIC Educational Resources Information Center

    Kamis, Arnold; Khan, Beverly K.

    2009-01-01

    How do we model and improve technical problem solving, such as network subnetting? This paper reports an experimental study that tested several hypotheses derived from Kolb's experiential learning cycle and Huber's problem solving model. As subjects solved a network subnetting problem, they mapped their mental processes according to Huber's…

  8. The Cyclic Nature of Problem Solving: An Emergent Multidimensional Problem-Solving Framework

    ERIC Educational Resources Information Center

    Carlson, Marilyn P.; Bloom, Irene

    2005-01-01

    This paper describes the problem-solving behaviors of 12 mathematicians as they completed four mathematical tasks. The emergent problem-solving framework draws on the large body of research, as grounded by and modified in response to our close observations of these mathematicians. The resulting "Multidimensional Problem-Solving Framework" has four…

  9. Pre-Service Class Teacher' Ability in Solving Mathematical Problems and Skills in Solving Daily Problems

    ERIC Educational Resources Information Center

    Aljaberi, Nahil M.; Gheith, Eman

    2016-01-01

    This study aims to investigate the ability of pre-service class teacher at University of Petrain solving mathematical problems using Polya's Techniques, their level of problem solving skills in daily-life issues. The study also investigates the correlation between their ability to solve mathematical problems and their level of problem solving…

  10. Lesion mapping of social problem solving.

    PubMed

    Barbey, Aron K; Colom, Roberto; Paul, Erick J; Chau, Aileen; Solomon, Jeffrey; Grafman, Jordan H

    2014-10-01

    Accumulating neuroscience evidence indicates that human intelligence is supported by a distributed network of frontal and parietal regions that enable complex, goal-directed behaviour. However, the contributions of this network to social aspects of intellectual function remain to be well characterized. Here, we report a human lesion study (n = 144) that investigates the neural bases of social problem solving (measured by the Everyday Problem Solving Inventory) and examine the degree to which individual differences in performance are predicted by a broad spectrum of psychological variables, including psychometric intelligence (measured by the Wechsler Adult Intelligence Scale), emotional intelligence (measured by the Mayer, Salovey, Caruso Emotional Intelligence Test), and personality traits (measured by the Neuroticism-Extraversion-Openness Personality Inventory). Scores for each variable were obtained, followed by voxel-based lesion-symptom mapping. Stepwise regression analyses revealed that working memory, processing speed, and emotional intelligence predict individual differences in everyday problem solving. A targeted analysis of specific everyday problem solving domains (involving friends, home management, consumerism, work, information management, and family) revealed psychological variables that selectively contribute to each. Lesion mapping results indicated that social problem solving, psychometric intelligence, and emotional intelligence are supported by a shared network of frontal, temporal, and parietal regions, including white matter association tracts that bind these areas into a coordinated system. The results support an integrative framework for understanding social intelligence and make specific recommendations for the application of the Everyday Problem Solving Inventory to the study of social problem solving in health and disease.

  11. Disciplinary Foundations for Solving Interdisciplinary Scientific Problems

    NASA Astrophysics Data System (ADS)

    Zhang, Dongmei; Shen, Ji

    2015-10-01

    Problem-solving has been one of the major strands in science education research. But much of the problem-solving research has been conducted on discipline-based contexts; little research has been done on how students, especially individuals, solve interdisciplinary problems. To understand how individuals reason about interdisciplinary problems, we conducted an interview study with 16 graduate students coming from a variety of disciplinary backgrounds. During the interviews, we asked participants to solve two interdisciplinary science problems on the topic of osmosis. We investigated participants' problem reasoning processes and probed in their attitudes toward general interdisciplinary approach and specific interdisciplinary problems. Through a careful inductive content analysis of their responses, we studied how disciplinary, cognitive, and affective factors influenced their interdisciplinary problems-solving. We found that participants' prior discipline-based science learning experiences had both positive and negative influences on their interdisciplinary problem-solving. These influences were embodied in their conceptualization of the interdisciplinary problems, the strategies they used to integrate different disciplinary knowledge, and the attitudes they had toward interdisciplinary approach in general and specific interdisciplinary problems. This study sheds light on interdisciplinary science education by revealing the complex relationship between disciplinary learning and interdisciplinary problem-solving.

  12. Lesion mapping of social problem solving

    PubMed Central

    Colom, Roberto; Paul, Erick J.; Chau, Aileen; Solomon, Jeffrey; Grafman, Jordan H.

    2014-01-01

    Accumulating neuroscience evidence indicates that human intelligence is supported by a distributed network of frontal and parietal regions that enable complex, goal-directed behaviour. However, the contributions of this network to social aspects of intellectual function remain to be well characterized. Here, we report a human lesion study (n = 144) that investigates the neural bases of social problem solving (measured by the Everyday Problem Solving Inventory) and examine the degree to which individual differences in performance are predicted by a broad spectrum of psychological variables, including psychometric intelligence (measured by the Wechsler Adult Intelligence Scale), emotional intelligence (measured by the Mayer, Salovey, Caruso Emotional Intelligence Test), and personality traits (measured by the Neuroticism-Extraversion-Openness Personality Inventory). Scores for each variable were obtained, followed by voxel-based lesion–symptom mapping. Stepwise regression analyses revealed that working memory, processing speed, and emotional intelligence predict individual differences in everyday problem solving. A targeted analysis of specific everyday problem solving domains (involving friends, home management, consumerism, work, information management, and family) revealed psychological variables that selectively contribute to each. Lesion mapping results indicated that social problem solving, psychometric intelligence, and emotional intelligence are supported by a shared network of frontal, temporal, and parietal regions, including white matter association tracts that bind these areas into a coordinated system. The results support an integrative framework for understanding social intelligence and make specific recommendations for the application of the Everyday Problem Solving Inventory to the study of social problem solving in health and disease. PMID:25070511

  13. Lesion mapping of social problem solving.

    PubMed

    Barbey, Aron K; Colom, Roberto; Paul, Erick J; Chau, Aileen; Solomon, Jeffrey; Grafman, Jordan H

    2014-10-01

    Accumulating neuroscience evidence indicates that human intelligence is supported by a distributed network of frontal and parietal regions that enable complex, goal-directed behaviour. However, the contributions of this network to social aspects of intellectual function remain to be well characterized. Here, we report a human lesion study (n = 144) that investigates the neural bases of social problem solving (measured by the Everyday Problem Solving Inventory) and examine the degree to which individual differences in performance are predicted by a broad spectrum of psychological variables, including psychometric intelligence (measured by the Wechsler Adult Intelligence Scale), emotional intelligence (measured by the Mayer, Salovey, Caruso Emotional Intelligence Test), and personality traits (measured by the Neuroticism-Extraversion-Openness Personality Inventory). Scores for each variable were obtained, followed by voxel-based lesion-symptom mapping. Stepwise regression analyses revealed that working memory, processing speed, and emotional intelligence predict individual differences in everyday problem solving. A targeted analysis of specific everyday problem solving domains (involving friends, home management, consumerism, work, information management, and family) revealed psychological variables that selectively contribute to each. Lesion mapping results indicated that social problem solving, psychometric intelligence, and emotional intelligence are supported by a shared network of frontal, temporal, and parietal regions, including white matter association tracts that bind these areas into a coordinated system. The results support an integrative framework for understanding social intelligence and make specific recommendations for the application of the Everyday Problem Solving Inventory to the study of social problem solving in health and disease. PMID:25070511

  14. Development of Reduction Technique of Thermal Stress Induced in Steel Plate Bonded by CFRP Plates

    NASA Astrophysics Data System (ADS)

    Ishikawa, Toshiyuki; Hattori, Atsushi; Kawano, Hirotaka; Nagao, Takashi; Kobayashi, Akira

    In CFRP bonded onto steel plate, thermal stress is induced in steel plate by temperature change, due to difference in coefficients of thermal expansion between steel and CFRP. In this study, reduction technique of the thermal stress in steel plate, which is additional bonding of aluminum alloy plates, is proposed. Namely, the coefficient of thermal expansion of composite plate consisted of CFRP and aluminum plates is designed as that of steel. In this research, to verify the effectiveness of developed method, heat tests of CFRP and aluminum plates bonded onto steel plate were carried out. As a result of the tests, infinitesimal thermal stresses in steel plate with CFRP and aluminum plates were measured while large thermal stresses were measured in conventional CFRP bonded onto steel plate. Additionally, to confirm the test results, numerical analysis was also carried out.

  15. 49 CFR 213.123 - Tie plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.123 Tie plates. (a) In Classes 3 through 5 track where timber crossties are in use there shall be tie plates under the running rails on at least eight...

  16. Epiphyseal plate transplantation: an historical review.

    PubMed

    Boyer, M I; Bray, P W; Bowen, C V

    1994-12-01

    Non-vascularized and vascularized transplantation of epiphyseal plate autografts have been performed both clinically and experimentally for over 100 years. However, the ultimate clinical goal of vascularized transplantation of epiphyseal plate allografts for paediatric extremity reconstruction remains elusive, due primarily to the lack of suitably nontoxic techniques to prevent graft rejection. We have summarized the published clinical and experimental investigations of vascularized epiphyseal plate transplantation, and organized the experiments and clinical operations into four main groups: (1) local vascular studies on unmanipulated epiphyseal plates, (2) studies of epiphyseal plate behaviour after orthotopic replantation, (3) studies of epiphyseal plate behaviour after heterotopic transplantation, and (4) studies of epiphyseal plate behaviour after allograft transplantation. Prior investigations into the non-vascularized transplantation of epiphyseal plate autografts and allografts are presented as background. These groups of studies serve as the building blocks for the more clinically applicable experimental investigations outlined in the final section of this review. PMID:7697285

  17. Maps, Plates, and Mount Saint Helens.

    ERIC Educational Resources Information Center

    Lary, Barbara E.; Krockover, Gerald H.

    1987-01-01

    Describes a laboratory activity on plate tectonics which focuses on the connection between plate tectonics and the different types of volcanoes. Provides questions for discussion and includes suggestions for extending the activity. (ML)

  18. Solving the Schroedinger equation using Smolyak interpolants

    SciTech Connect

    Avila, Gustavo; Carrington, Tucker Jr.

    2013-10-07

    In this paper, we present a new collocation method for solving the Schroedinger equation. Collocation has the advantage that it obviates integrals. All previous collocation methods have, however, the crucial disadvantage that they require solving a generalized eigenvalue problem. By combining Lagrange-like functions with a Smolyak interpolant, we device a collocation method that does not require solving a generalized eigenvalue problem. We exploit the structure of the grid to develop an efficient algorithm for evaluating the matrix-vector products required to compute energy levels and wavefunctions. Energies systematically converge as the number of points and basis functions are increased.

  19. Practical automatic Arabic license plate recognition system

    NASA Astrophysics Data System (ADS)

    Mohammad, Khader; Agaian, Sos; Saleh, Hani

    2011-02-01

    Since 1970's, the need of an automatic license plate recognition system, sometimes referred as Automatic License Plate Recognition system, has been increasing. A license plate recognition system is an automatic system that is able to recognize a license plate number, extracted from image sensors. In specific, Automatic License Plate Recognition systems are being used in conjunction with various transportation systems in application areas such as law enforcement (e.g. speed limit enforcement) and commercial usages such as parking enforcement and automatic toll payment private and public entrances, border control, theft and vandalism control. Vehicle license plate recognition has been intensively studied in many countries. Due to the different types of license plates being used, the requirement of an automatic license plate recognition system is different for each country. [License plate detection using cluster run length smoothing algorithm ].Generally, an automatic license plate localization and recognition system is made up of three modules; license plate localization, character segmentation and optical character recognition modules. This paper presents an Arabic license plate recognition system that is insensitive to character size, font, shape and orientation with extremely high accuracy rate. The proposed system is based on a combination of enhancement, license plate localization, morphological processing, and feature vector extraction using the Haar transform. The performance of the system is fast due to classification of alphabet and numerals based on the license plate organization. Experimental results for license plates of two different Arab countries show an average of 99 % successful license plate localization and recognition in a total of more than 20 different images captured from a complex outdoor environment. The results run times takes less time compared to conventional and many states of art methods.

  20. Electrically induced mechanical precompression of ferroelectric plates

    DOEpatents

    Chen, P.J.

    1987-03-02

    A method of electrically inducing mechanical precompression of ferroelectric plate covered with electrodes utilizes the change in strains of the plate as functions of applied electric field. A first field polarizes and laterally shrinks the entire plate. An outer portion of the electrodes are removed, and an opposite field partially depolarizes and expands the central portion of the plate against the shrunk outer portion. 2 figs.

  1. Electrically induced mechanical precompression of ferroelectric plates

    DOEpatents

    Chen, Peter J.

    1987-01-01

    A method of electrically inducing mechanical precompression of a ferroelectric plate covered with electrodes utilizes the change in strains of the plate as functions of applied electric field. A first field polarizes and laterally shrinks the entire plate. An outer portion of the electrodes are removed, and an opposite field partially depolarizes and expands the central portion of the plate against the shrunk outer portion.

  2. Axisymmetric vibrations of layered tapered plates

    NASA Astrophysics Data System (ADS)

    Navaneethakrishnan, P. V.; Chandrasekaran, K.; Ravisrinivas, N.

    1992-12-01

    The study of Navaneethakrishnan and Chandrasekaran (1989) on axisymmetric free vibrations of layered annular plates is extended to the vibrations of layered annular plates whose thickness can vary as the radial distance from the arbitrary concentric circle. Numerical results are presented, showing the relationship between the circular frequency of the plate vibration and the ratio between the inner and the outer radii of the plate.

  3. Electrochemical Assay of Gold-Plating Solutions

    NASA Technical Reports Server (NTRS)

    Chiodo, R.

    1982-01-01

    Gold content of plating solution is assayed by simple method that required only ordinary electrochemical laboratory equipment and materials. Technique involves electrodeposition of gold from solution onto electrode, the weight gain of which is measured. Suitable fast assay methods are economically and practically necessary in electronics and decorative-plating industries. If gold content in plating bath is too low, poor plating may result, with consequent economic loss to user.

  4. A non-classical Mindlin plate model incorporating microstructure, surface energy and foundation effects

    NASA Astrophysics Data System (ADS)

    Gao, X.-L.; Zhang, G. Y.

    2016-07-01

    A non-classical model for a Mindlin plate resting on an elastic foundation is developed in a general form using a modified couple stress theory, a surface elasticity theory and a two-parameter Winkler-Pasternak foundation model. It includes all five kinematic variables possible for a Mindlin plate. The equations of motion and the complete boundary conditions are obtained simultaneously through a variational formulation based on Hamilton's principle, and the microstructure, surface energy and foundation effects are treated in a unified manner. The newly developed model contains one material length-scale parameter to describe the microstructure effect, three surface elastic constants to account for the surface energy effect, and two foundation parameters to capture the foundation effect. The current non-classical plate model reduces to its classical elasticity-based counterpart when the microstructure, surface energy and foundation effects are all suppressed. In addition, the new model includes the Mindlin plate models considering the microstructure dependence or the surface energy effect or the foundation influence alone as special cases, recovers the Kirchhoff plate model incorporating the microstructure, surface energy and foundation effects, and degenerates to the Timoshenko beam model including the microstructure effect. To illustrate the new Mindlin plate model, the static bending and free vibration problems of a simply supported rectangular plate are analytically solved by directly applying the general formulae derived.

  5. A simple higher order shear deformation theory for mechanical behavior of laminated composite plates

    NASA Astrophysics Data System (ADS)

    Adim, Belkacem; Daouadji, Tahar Hassaine; Rabahi, Aberezak

    2016-06-01

    In the present study, the static, buckling, and free vibration of laminated composite plates is examined using a refined shear deformation theory and developed for a bending analysis of orthotropic laminated composite plates. These models take into account the parabolic distribution of transverse shear stresses and satisfy the condition of zero shear stresses on the top and bottom surfaces of the plates. The most interesting feature of this theory is that it allows for parabolic distributions of transverse shear stresses across the plate thickness and satisfies the conditions of zero shear stresses at the top and bottom surfaces of the plate without using shear correction factors. The number of independent unknowns in the present theory is four, as against five in other shear deformation theories. In the analysis, the equation of motion for simply supported thick laminated rectangular plates is obtained through the use of Hamilton's principle. The accuracy of the analysis presented is demonstrated by comparing the results with solutions derived from other higher order models and with data found in the literature. It can be concluded that the proposed theory is accurate and simple in solving the static, the buckling, and free vibration behaviors of laminated composite plates.

  6. Modeling of composite beams and plates for static and dynamic analysis

    NASA Technical Reports Server (NTRS)

    Hodges, Dewey H.; Sutyrin, Vladislav G.; Lee, Bok Woo

    1993-01-01

    The main purpose of this research was to develop a rigorous theory and corresponding computational algorithms for through-the-thickness analysis of composite plates. This type of analysis is needed in order to find the elastic stiffness constants for a plate and to post-process the resulting plate solution in order to find approximate three-dimensional displacement, strain, and stress distributions throughout the plate. This also requires the development of finite deformation plate equations which are compatible with the through-the-thickness analyses. After about one year's work, we settled on the variational-asymptotical method (VAM) as a suitable framework in which to solve these types of problems. VAM was applied to laminated plates with constant thickness in the work of Atilgan and Hodges. The corresponding geometrically nonlinear global deformation analysis of plates was developed by Hodges, Atilgan, and Danielson. A different application of VAM, along with numerical results, was obtained by Hodges, Lee, and Atilgan. An expanded version of this last paper was submitted for publication in the AIAA Journal.

  7. Electroless metal plating of plastics

    DOEpatents

    Krause, Lawrence J.

    1984-01-01

    Process for plating main group metals on aromatic polymers is carried out by the use of a nonaqueous solution of a salt of an alkali metal in a positive valence state and a main group metal in a negative valence state with contact between the solution and polymer providing a redox reaction causing the deposition of the main group metal and the reduction of the polymer. Products from the process exhibit useful decorative and electrical properties.

  8. Electroless metal plating of plastics

    DOEpatents

    Krause, Lawrence J.

    1986-01-01

    Process for plating main group metals on aromatic polymers is carried out by the use of a nonaqueous solution of a salt of an alkali metal in a positive valence state and a main group metal in a negative valence state with contact between the solution and polymer providing a redox reaction causing the deposition of the main group metal and the reduction of the polymer. Products from the process exhibit useful decorative and electrical properties.

  9. Electroless metal plating of plastics

    DOEpatents

    Krause, L.J.

    1982-09-20

    Process for plating main group metals on aromatic polymers is carried out by the use of a nonaqueous solution of a salt of an alkali metal in a positive valence state and a main group metal in a negative valence state with contact between the solution and polymer providing a redox reaction causing the deposition of the main group metal and the reduction of the polymer. Products from the process exhibit useful decorative and electrical properties.

  10. Ion plated electronic tube device

    DOEpatents

    Meek, T.T.

    1983-10-18

    An electronic tube and associated circuitry which is produced by ion plating techniques. The process is carried out in an automated process whereby both active and passive devices are produced at very low cost. The circuitry is extremely reliable and is capable of functioning in both high radiation and high temperature environments. The size of the electronic tubes produced are more than an order of magnitude smaller than conventional electronic tubes.

  11. Syncytial-Type Cell Plates

    PubMed Central

    Otegui, Marisa; Staehelin, L. Andrew

    2000-01-01

    Cell wall formation in the syncytial endosperm of Arabidopsis was studied by using high-pressure-frozen/freeze-substituted developing seeds and immunocytochemical techniques. The endosperm cellularization process begins at the late globular embryo stage with the synchronous organization of small clusters of oppositely oriented microtubules (∼10 microtubules in each set) into phragmoplast-like structures termed mini-phragmoplasts between both sister and nonsister nuclei. These mini-phragmoplasts produce a novel kind of cell plate, the syncytial-type cell plate, from Golgi-derived vesicles ∼63 nm in diameter, which fuse by way of hourglass-shaped intermediates into wide (∼45 nm in diameter) tubules. These wide tubules quickly become coated and surrounded by a ribosome-excluding matrix; as they grow, they branch and fuse with each other to form wide tubular networks. The mini-phragmoplasts formed between a given pair of nuclei produce aligned tubular networks that grow centrifugally until they merge into a coherent wide tubular network with the mini-phragmoplasts positioned along the network margins. The individual wide tubular networks expand laterally until they meet and eventually fuse with each other at the sites of the future cell corners. Transformation of the wide tubular networks into noncoated, thin (∼27 nm in diameter) tubular networks begins at multiple sites and coincides with the appearance of clathrin-coated budding structures. After fusion with the syncytial cell wall, the thin tubular networks are converted into fenestrated sheets and cell walls. Immunolabeling experiments show that the cell plates and cell walls of the endosperm differ from those of the embryo and maternal tissue in two features: their xyloglucans lack terminal fucose residues on the side chain, and callose persists in the cell walls after the cell plates fuse with the parental plasma membrane. The lack of terminal fucose residues on xyloglucans suggests that these cell wall

  12. PRETREATING URANIUM FOR METAL PLATING

    DOEpatents

    Wehrmann, R.F.

    1961-05-01

    A process is given for anodically treating the surface of uranium articles, prior to metal plating. The metal is electrolyzed in an aqueous solution of about 10% polycarboxylic acid, preferably oxalic acid, from 1 to 5% by weight of glycerine and from 1 to 5% by weight of hydrochloric acid at from 20 to 75 deg C for from 30 seconds to 15 minutes. A current density of from 60 to 100 amperes per square foot is used.

  13. Episodic plate tectonics on Venus

    NASA Technical Reports Server (NTRS)

    Turcotte, Donald

    1992-01-01

    Studies of impact craters on Venus from the Magellan images have placed important constraints on surface volcanism. Some 840 impact craters have been identified with diameters ranging from 2 to 280 km. Correlations of this impact flux with craters on the Moon, Earth, and Mars indicate a mean surface age of 0.5 +/- 0.3 Ga. Another important observation is that 52 percent of the craters are slightly fractured and only 4.5 percent are embayed by lava flows. These observations led researchers to hypothesize that a pervasive resurfacing event occurred about 500 m.y. ago and that relatively little surface volcanism has occurred since. Other researchers have pointed out that a global resurfacing event that ceased about 500 MYBP is consistent with the results given by a recent study. These authors carried out a series of numerical calculations of mantle convection in Venus yielding thermal evolution results. Their model considered crustal recycling and gave rapid planetary cooling. They, in fact, suggested that prior to 500 MYBP plate tectonics was active in Venus and since 500 MYBP the lithosphere has stabilized and only hot-spot volcanism has reached the surface. We propose an alternative hypothesis for the inferred cessation of surface volcanism on Venus. We hypothesize that plate tectonics on Venus is episodic. Periods of rapid plate tectonics result in high rates of subduction that cool the interior resulting in more sluggish mantle convection.

  14. Volcano spacing and plate rigidity

    SciTech Connect

    Brink, U. )

    1991-04-01

    In-plane stresses, which accompany the flexural deformation of the lithosphere under the load adjacent volcanoes, may govern the spacing of volcanoes in hotspot provinces. Specifically, compressive stresses in the vicinity of a volcano prevent new upwelling in this area, forcing a new volcano to develop at a minimum distance that is equal to the distance in which the radial stresses change from compressional to tensile (the inflection point). If a volcano is modeled as a point load on a thin elastic plate, then the distance to the inflection point is proportional to the thickness of the plate to the power of 3/4. Compilation of volcano spacing in seven volcanic groups in East Africa and seven volcanic groups of oceanic hotspots shows significant correlation with the elastic thickness of the plate and matches the calculated distance to the inflection point. In contrast, volcano spacing in island arcs and over subduction zones is fairly uniform and is much larger than predicted by the distance to the inflection point, reflecting differences in the geometry of the source and the upwelling areas.

  15. MTR plates modeling with MAIA

    SciTech Connect

    Marelle, V.; Dubois, S.; Ripert, M.; Noirot, J.

    2008-07-15

    MAIA is a thermo-mechanical code dedicated to the modeling of MTR fuel plates. The main physical phenomena modeled in the code are the cladding oxidation, the interaction between fuel and Al-matrix, the swelling due to fission products and the Al/fuel particles interaction. The creeping of the plate can be modeled in the mechanical calculation. MAIA has been validated on U-Mo dispersion fuel experiments such as IRIS 1 and 2 and FUTURE. The results are in rather good agreement with post-irradiation examinations. MAIA can also be used to calculate in-pile behavior of U{sub 3}Si{sub 2} plates as in the SHARE experiment irradiated in the SCK/Mol BR2 reactor. The main outputs given by MAIA throughout the irradiation are temperatures, cladding oxidation thickness, interaction thickness, volume fraction of meat constituents, swelling, displacements, strains and stresses. MAIA is originally a two-dimensional code but a three-dimensional version is currently under development. (author)

  16. Plating of proximal humeral fractures.

    PubMed

    Martetschläger, Frank; Siebenlist, Sebastian; Weier, Michael; Sandmann, Gunther; Ahrens, Philipp; Braun, Karl; Elser, Florian; Stöckle, Ulrich; Freude, Thomas

    2012-11-01

    The optimal treatment for proximal humeral fractures is controversial. Few data exist concerning the influence of the surgical approach on the outcome. The purpose of this study was to evaluate the clinical and radiological outcomes of proximal humeral fractures treated with locking plate fixation through a deltopectoral vs an anterolateral deltoid-splitting approach. Of 86 patients who met the inclusion criteria, 70 were available for follow-up examination. Thirty-three patients were treated through a deltopectoral approach and 37 through an anterolateral deltoid-splitting approach. In all cases, open reduction and internal fixation with a PHILOS locking plate (Synthes, Umkirch, Germany) was performed. Clinical follow-up included evaluation of pain, shoulder mobility, and strength. Constant score and Disabilities of the Arm, Shoulder and Hand (DASH) score were assessed. A clinical neurological examination of the axillary nerve was also performed. Consolidation, reduction, and appearance of head necrosis were evaluated radiographically. After a mean follow-up of 33 months, Constant scores, DASH scores, and American Shoulder and Elbow Surgeons scores showed no significant differences between the groups. Clinical neurologic examination of the axillary nerve revealed no obvious damage to the nerve in either group. Deltopectoral and anterolateral detoid-splitting approaches for plate fixation of proximal humeral fractures are safe and provide similar clinical outcomes. The results of this study suggest that the approach can be chosen according to surgeon preference.

  17. 46 CFR 169.665 - Name plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Name plates. 169.665 Section 169.665 Shipping COAST... Gross Tons § 169.665 Name plates. Each generator, motor and other major item f power equipment must be provided with a name plate indicating the manufacturer's name, its rating in volts and amperes or in...

  18. 46 CFR 169.665 - Name plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Name plates. 169.665 Section 169.665 Shipping COAST... Gross Tons § 169.665 Name plates. Each generator, motor and other major item f power equipment must be provided with a name plate indicating the manufacturer's name, its rating in volts and amperes or in...

  19. Apparatus and method for controlling plating uniformity

    DOEpatents

    Hachman Jr., John T.; Kelly, James J.; West, Alan C.

    2004-10-12

    The use of an insulating shield for improving the current distribution in an electrochemical plating bath is disclosed. Numerical analysis is used to evaluate the influence of shield shape and position on plating uniformity. Simulation results are compared to experimental data for nickel deposition from a nickel--sulfamate bath. The shield is shown to improve the average current density at a plating surface.

  20. FASTENER FOR AN ASSEMBLY OF PLATES

    DOEpatents

    Groh, E.F.

    1963-08-20

    A fastener is provided for a spaced-apart parallel plate fuel assembly. The fastener, attached by screws to a key that passes through the edges of the assembled plate, serves as a retainer for the outermost plate as well as a bidirectional spacer for separating the fuel assembly from two neighboring fuel assemblies. (AEC)