Science.gov

Sample records for prefabricated structures

  1. 41 CFR 102-75.160 - Should prefabricated movable structures be designated real or personal property for disposition...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Should prefabricated movable structures be designated real or personal property for disposition purposes? 102-75.160 Section 102-75.160 Public Contracts and Property Management Federal Property Management Regulations...

  2. 41 CFR 102-75.160 - Should prefabricated movable structures be designated real or personal property for disposition...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Should prefabricated movable structures be designated real or personal property for disposition purposes? 102-75.160 Section 102-75.160 Public Contracts and Property Management Federal Property Management Regulations...

  3. 41 CFR 102-75.160 - Should prefabricated movable structures be designated real or personal property for disposition...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Should prefabricated movable structures be designated real or personal property for disposition purposes? 102-75.160 Section 102-75.160 Public Contracts and Property Management Federal Property Management Regulations...

  4. 41 CFR 102-75.160 - Should prefabricated movable structures be designated real or personal property for disposition...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Should prefabricated movable structures be designated real or personal property for disposition purposes? 102-75.160 Section 102-75.160 Public Contracts and Property Management Federal Property Management Regulations...

  5. 41 CFR 102-75.160 - Should prefabricated movable structures be designated real or personal property for disposition...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Should prefabricated movable structures be designated real or personal property for disposition purposes? 102-75.160 Section 102-75.160 Public Contracts and Property Management Federal Property Management Regulations...

  6. Use of prefabricated titanium abutments and customized anatomic lithium disilicate structures for cement-retained implant restorations in the esthetic zone.

    PubMed

    Lin, Wei-Shao; Harris, Bryan T; Zandinejad, Amirali; Martin, William C; Morton, Dean

    2014-03-01

    This report describes the fabrication of customized abutments consisting of prefabricated 2-piece titanium abutments and customized anatomic lithium disilicate structures for cement-retained implant restorations in the esthetic zone. The heat-pressed lithium disilicate provides esthetic customized anatomic structures and crowns independently of the computer-aided design and computer-aided manufacturing process. PMID:24360007

  7. BRITISH PREFABRICATED SCHOOL CONSTRUCTION.

    ERIC Educational Resources Information Center

    Stanford Univ., CA. School Planning Lab.

    AT THE END OF WORLD WAR II, ENGLAND EXPERIENCED A SHORTAGE OF TRADITIONAL BUILDING MATERIALS WHILE HAVING TO FACE THE PROBLEM OF PROVIDING MORE THAN 1 MILLION PLACES FOR SCHOOL CHILDREN IN 7 YEARS. IN 1946, THE COUNTY OF HERTFORDSHIRE BEGAN USING PREFABRICATED STANDARDIZED MATERIALS FOR SCHOOL CONSTRUCTION TO MEET THIS NEED. STANDARDIZATION HAS SO…

  8. The Prefabricated Interior Design Studio: An Exploration into the History and Sustainability of Interior Prefabrication

    ERIC Educational Resources Information Center

    Schneiderman, Deborah; Freihoefer, Kara

    2013-01-01

    This article examines the integration of prefabrication into an interior design studio. A review of the literature revealed that while there is a paucity of categorical research focused on this subject, the subject is historically significant with an abundance of evidence regarding the prefabrication of the interior environment dating back…

  9. Prefabricated stock trays for impression of auricular region.

    PubMed

    Vibha, Shetty; Anandkrishna, G N; Anupam, Purwar; Namratha, N

    2010-06-01

    The conventional methods of impression making for maxillofacial defects are cumbersome and time consuming for both patient and operator. This study focuses upon standardizing and simplifying the impression making methodology for auricular prosthesis with the help of prefabricated stock trays for auricular region. The stock trays were designed on positive replicas of anatomical structures, broadly divided into long and narrow, short and broad and long and broad ear. For each stock tray, impressions of auricle, of patients of different morphology were made with plastic funnels of different shape and size ensuring at least 6 mm of space between the anatomical part and inner surface of funnel and master cast was obtained. Subsequent adaptation of wax was done and fabrications of stock stainless steel trays were done. A standardized stock tray for making of auricular impressions was developed. From this innovative technical procedure it is possible to get an accurate impression of auricular defects now by the use of prefabricated stock trays rather than the cumbersome conventional method. PMID:21629455

  10. Studies of the Prefabricated Housing Construction Market in Poland

    NASA Astrophysics Data System (ADS)

    Radziszewska-Zielina, Elżbieta; Gleń, Monika

    2014-11-01

    The directions of development of the construction market are not only related to the need to own one's own home but also to increasing functional and economic requirements and conditions of sustainable development. The perception and understanding of prefabrication in housing construction are undoubtedly starting to change. Sustainable construction criteria may constitute a significant turning point and support for the development of new prefabricated housing construction technologies. Entrepreneurs are slowly perceiving an opportunity for the development of prefabrication in the construction market. The implementation and popularisation of ready-made homes will undoubtedly constitute a favourable change in the Polish construction market; however, this will require a modification of habits. This article presents an historical analysis of the development of the prefabricated housing construction market as well as an attempt to answer questions concerning the future of prefabrication in housing construction in Poland based on the conducted studies.

  11. Occupational dermatitis in a prefabrication construction factory.

    PubMed

    Goh, C L; Gan, S L; Ngui, S J

    1986-10-01

    In a field study of occupational dermatoses in a prefabrication construction factory, 272 workers were interviewed, examined and patch tested to chromate, cobalt, nickel, rubber mixes, epoxy resin, melamine formaldehyde and conplasts. The prevalence of occupational dermatitis was 14% (38/272); 57% (22/38) were irritant dermatitis from cement; 39.5% (15/38) were allergic contact dermatitis from cement (2 with concomitant rubber glove allergy); and 2.5% (1/38) were allergic to rubber chemicals in gloves. The overall prevalence of chromate sensitivity was 8.5% (23/272), with the highest rate from the concreting bays of the factory. The rate was unrelated to the duration of workers' engagement in construction work. 34.8% (8/23) had asymptomatic chromate allergy. The prevalence of cobalt reactions was 17.4% (4/23) and all were associated with chromate allergy. PMID:2948758

  12. The use of prefabrication technique in microvascular reconstructive surgery

    PubMed Central

    Maciejewski, Adam; Szymczyk, Cezary; Wierzgoń, Janusz; Szumniak, Ryszard; Jędrzejewski, Piotr; Grajek, Maciej; Dobrut, Mirosław; Ulczok, Rafał; Półtorak, Stanisław

    2013-01-01

    Aim of the study The aim of the study was to develop standards for the prefabrication of free microvascular flaps in an animal model, followed by their application in clinical practice, and quantitative/qualitative microscopic assessment of the extent of development of a new microvascular network. Material and methods The study was carried out in 10 experimental pigs. As the first stage, a total of 20 prefabricated flaps were created using polytetrafluoroethylene (PTFE) as a support material, placed horizontally over an isolated and distally closed vascular pedicle based on superficial abdominal vessels. After completing the animal model study, one patient was selected for the grafting of the prefabricated free flap. Results All 20 free flaps prefabricated in the animal model were analyzed microscopically, exhibiting connective tissue rich in fibroblasts and small blood vessels in the porous areas across the entire thickness of the PTFE element. Conclusions Flap prefabrication is a new and fast developing reconstruction technique. The usefulness of prefabrication techniques and their status in reconstructive surgery still needs to be investigated experimentally and clinically. The method based on prefabricated free flaps is the first step towards anatomical bioengineering that will make it possible to replace missing organs with their anatomically perfect equivalents. PMID:23788942

  13. Prefabrication and prelamination strategies for the reconstruction of complex defects of trachea and larynx.

    PubMed

    Vranckx, J J; Den Hondt, M; Delaere, P

    2014-03-01

    Complex tracheal and laryngeal defects can be reconstructed using prelamination and prefabrication techniques. Three clinical situations are described in detail in the article. In short segment restenosis defects within scarred surroundings, we restore the fibrocartilaginous defect with a radial forearm fascia flap prelaminated with buccal mucosa or cartilage. This provides a newly vascularized inner lining to the tracheal defect and restores the tubular convexity. For long segment defects we need a technique that can withstand respiratory forces. We use a heterotopic prefabrication strategy to vascularize a tracheal allograft wrapped in forearm fascia. Chimerism is created by replacing donor respiratory epithelium with buccal mucosa of the recipient. After orthotopic transfer, this chimerism allows immunosuppression to be tapered and stopped when bronchoscopy shows mucosal integrity of the new trachea, since the recipient epithelium replaces the allogeneic inner tracheal lining by means of a chronic rejection process. A distinct situation occurs after resection of a unilateral larynx tumor, which usually results in a total laryngectomy with loss of both vocal cords, since reconstruction of the hemilarynx is considered too complex. First, we prefabricate a nearby four-ring autologous tracheal segment using radial forearm fascia. In a second stage, this orthotopically vascularized trachea restores the laryngeal structure with the aim to conserve one vocal cord and thus speech. Orthotopic and heterotopic prelamination and prefabrication strategies offer efficient and reproducible solutions for the restoration of challenging short and long segment tracheal defects, as well as unilateral laryngeal defects. The series in this review article are based on previous studies and case reports. The level of evidence is III-"Study of nonconsecutive patients, without a universally applied gold standard: case-control study". PMID:24399691

  14. Mechanical properties of roots combined with prefabricated fiber post.

    PubMed

    Kono, Takashi; Yoshinari, Masao; Takemoto, Shinji; Hattori, Masayuki; Kawada, Eiji; Oda, Yutaka

    2009-09-01

    This study examined the mechanical properties of roots combined with prefabricated fiber post. Three types of specimens were evaluated: (1) prefabricated fiber post alone (FP); (2) core composite resin with FP (CFP); and (3) root with CFP (RCFP). The volume fractions of the prefabricated fiber post in the core composite resin (FP/CFP ratio) were set to 0, 0.16, 0.22, 0.28, and 0.48. Bending test for FP and CFP, and diametral compression test for FP, CFP, and RCFP were carried out. The FP/CFP ratio showed no effect on the diametral tensile strength (DTS) of RCFP; and there were no significant differences in DTS with/without FP. The flexural strength of CFP increased with increase in FP/CFP ratio. The DTS of CFP declined in comparison with that of core composite resin only. PMID:19822983

  15. Prefabrication: A History of Its Development in Great Britain.

    ERIC Educational Resources Information Center

    Building Research Establishment, Watford (England).

    A history of prefabrication in Britain from the first Victorian innovations in wood, glass, and cast iron, through the developments of the inter-war years and the buildings of the immediate post-war period to the 'system building' of today is presented. The study is not confined to houses and flats but examines the influences of non-traditional…

  16. 4. Prefabricated concrete panel portion of Snowshed 29 abutting west ...

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

    4. Prefabricated concrete panel portion of Snowshed 29 abutting west portal of Tunnel 41, view to east, 135mm lens. Function of the elevated portion is unknown, but it may help to channel exhaust fumes out of the shed and the two-mile long tunnel. - Central Pacific Transcontinental Railroad, Tunnel No. 41, Milepost 193.3, Donner, Placer County, CA

  17. Cryogenic line insulation made from prefabricated polyurethane shells

    NASA Technical Reports Server (NTRS)

    Lerma, G.

    1975-01-01

    Prefabricated polyurethane foam insulation is inexpensive and easily installed on cryogenic lines. Insulation sections are semicircular half shells. Pair of half shells is placed to surround cryogenic line. Cylindrically-shaped knit sock is pulled over insulation then covered with polyurethane resin to seal system.

  18. Changes of postural steadiness following use of prefabricated orthotic insoles.

    PubMed

    Bateni, Hamid

    2013-04-01

    Orthoses are designed to assist a malaligned foot in adapting to the environment and reduce the frequency of injury. Literature is divided on the benefits of orthotics insoles for postural stability. The current study was conducted to determine the effect of prefabricated orthotic arch supports on postural stabilization. Twelve healthy young adults participated in this study and were tested with and without prefabricated orthotics. Different variables were computed from movement of center of pressure (COP) during orthotic use as suggested in the literature. The mean position of COP was significantly shifted forward and toward the dominant side. Neither the COP movement nor the velocity changes following the use of orthotics revealed significant differences. Mediolateral range of COP movement and the 95% confidence circle area of sway was significantly reduced (P = .022 and 0.048 respectively), but changes in 95% confidence circle and ellipse areas of fractal dimension were not significant (P = .053 and P = .057 respectively). In conclusion, orthotic insoles significantly improved postural sway initially by reducing mediolateral range of postural sway and 95% confidence circle area of sway at the cost of increased fractal dimension area variables and power. PMID:22815281

  19. Prefabricated light-polymerizing plastic pattern for partial denture framework.

    PubMed

    Takaichi, Atsushi; Wakabayashi, Noriyuki; Igarashi, Yoshimasa

    2011-10-01

    Our aim is to report an application of a prefabricated light-polymerizing plastic pattern to construction of removable partial denture framework without the use of a refractory cast. A plastic pattern for the lingual bar was adapted on the master cast of a mandibular Kennedy class I partially edentulous patient. The pattern was polymerized in a light chamber. Cobalt-chromium wires were employed to minimize the potential distortion of the plastic framework. The framework was carefully removed from the master cast and invested with phosphate-bonded investment for the subsequent casting procedures. A retentive clasp was constructed using 19-gauge wrought wire and was welded to the framework by means of laser welding machine. An excellent fit of the framework in the patient's mouth was observed in the try-in and the insertion of the denture. The result suggests that this method minimizes laboratory cost and time for partial denture construction. PMID:22346178

  20. Prefabricated light-polymerizing plastic pattern for partial denture framework

    PubMed Central

    Takaichi, Atsushi; Wakabayashi, Noriyuki; Igarashi, Yoshimasa

    2011-01-01

    Our aim is to report an application of a prefabricated light-polymerizing plastic pattern to construction of removable partial denture framework without the use of a refractory cast. A plastic pattern for the lingual bar was adapted on the master cast of a mandibular Kennedy class I partially edentulous patient. The pattern was polymerized in a light chamber. Cobalt–chromium wires were employed to minimize the potential distortion of the plastic framework. The framework was carefully removed from the master cast and invested with phosphate-bonded investment for the subsequent casting procedures. A retentive clasp was constructed using 19-gauge wrought wire and was welded to the framework by means of laser welding machine. An excellent fit of the framework in the patient's mouth was observed in the try-in and the insertion of the denture. The result suggests that this method minimizes laboratory cost and time for partial denture construction. PMID:22346178

  1. Prefabricated foldable lunar base modular systems for habitats, offices, and laboratories

    NASA Technical Reports Server (NTRS)

    Hijazi, Yousef

    1992-01-01

    The first habitat and work station on the lunar surface undoubtedly has to be prefabricated, self-erecting, and self-contained. The building structure should be folded and compacted to the minimum size and made of materials of minimum weight. It must also be designed to provide maximum possible habitable and usable space on the Moon. For this purpose the concept of multistory, foldable structures was further developed. The idea is to contain foldable structural units in a cylinder or in a capsule adapted for launching. Upon landing on the lunar surface, the cylinder of the first proposal in this paper will open in two hinge-connected halves while the capsule of the second proposal will expand horizontally and vertically in all directions. In both proposals, the foldable structural units will self-erect providing a multistory building with several room enclosures. The solar radiation protection is maintained through regolith-filled pneumatic structures as in the first proposal, or two regolith-filled expandable capsule shells as in the second one, which provide the shielding while being supported by the erected internal skeletal structure.

  2. Sick building syndrome in like symptoms in emergency prefabricated accommodation.

    PubMed

    Muzi, G; Accattoli, M P; dell'Omo, M; Frillici, C; Sapia, I E; Abbritti, G

    2004-01-01

    The present study investigated the sources of discomfort and the symptoms reported by earthquake victims residing in temporary emergency prefabricated accommodation (prefab). The investigation was carried out by means of a questionnaire. 203 prefab occupants and 13 inhabitants of houses, who were chosen as reference population, replied in winter and 233 prefab occupants and 154 inhabitants of houses replied in summer. In both seasons more people living in prefabs indentified dry air, stuffy air, stale air, dust, dampness, uncomfortable temperature and bad odours as sources of discomfort. They also complained of general symptoms (headache, irritablility, insomnia, difficulty in concentration) and irritative symptoms of the eyes, upper and lower airways and skin. Multiple regression analysis identified the type of accommodation as the variable that most influenced the onset of general, ocular, upper and lower airway symptoms. Intrinsic characteristics of the prefabs (being constructed with synthetic materials, combustion sources, poor ventilation and insulation) and psychosocial factors e. losing their home, could have contributed to the onset of symptoms. PMID:15345200

  3. Prefabricated Refractory Panels for Use in KSC's Flame Deflectors: A Feasibility Study

    NASA Technical Reports Server (NTRS)

    Calle, Luz Maria; Trejo, David

    2010-01-01

    The launch complexes at the John F. Kennedy Space Center (KSC) have been used to launch space vehicles for the Apollo and Space Shuttle programs. NASA is currently designing and developing a new space vehicle. The launch complexes have been in service for a significant duration and the aggressive conditions of the Florida coast and the launches have resulted in failures within the launch complexes. Of particular interests is the performance of the refractory lining that covers the steel base structure for the diversion of the exhaust from the launched vehicles (i.e., the flame deflectors). An unprotected steel base structure would likely experience loss of strength and possible failure when subjected to the high temperatures during launches. The refractory lining is critical for successful launches. The refractory material currently used in the flame trenches was developed in 1959 and is the only refractory material approved for use in these facilities. Significant effort and costs are expended in repairing the lining system after each launch. NASA is currently performing a comprehensive research program to assess and develop refractory materials for improved performance in the flame trenches. However, one challenge associated with the use of refractory materials in the flame trench is that the materials should be cured, dried, and fired to maximize their properties and characteristics. Because of the large size of the deflectors and trenches, drying and firing of the lining system is difficult, if not impossible. Most refractory materials are dried and fired before use. Because the refractory materials used for the deflector lining cannot be dried and fired, the full potential of the materials are not being realized. A system that could use refractory materials that could be cured, dried, and sintered in a controlled environment would likely improve the performance of the lining system. This report evaluates the feasibility of fabricating and placing prefabricated

  4. Pediatric airway reconstruction with a prefabricated auricular cartilage and radial forearm free flap.

    PubMed

    Ahmad, Faisal I; O'Dell, Karla; Peck, Jessica J; Wax, Mark K; Milczuk, Henry A

    2015-08-01

    Prefabricated composite free flaps for complex airway reconstruction have been described for an adult series at our institution. We extended this approach to a pediatric patient with lifelong subglottic stenosis who had failed previous open airway reconstructions. A staged procedure was utilized in which a composite graft was created using conchal cartilages and a radial forearm free flap. This reconstruction improved the patency of her airway and decreased her dependency on intermittent airway dilations. Airway reconstruction with prefabricated conchal cartilage composite free flaps may be used as a salvage procedure for complex pediatric airway reconstruction when other methods have failed. PMID:25645935

  5. Reconstruction of the mandible by prefabricated autogenous bone grafts. An experimental study in minipigs.

    PubMed

    Schliephake, H; Langner, M

    1997-08-01

    The aim of the present experimental study was to evaluate the use of prefabricated bone grafts for reconstruction of the mandible. In 20 adult Göttingen minipigs, prefabricated bone grafts 10 x 12 x 40 mm in size were cultivated in scaffolds of pyrolized bovine bone under a polylactic membrane on the outside of the mandible during a period of five months. The grafts were harvested and transferred to bridge 2- and 4-cm lower mandibular border defects and discontinuity defects. Five animals served as ungrafted controls and evaluation of the grafts was performed three and five months after grafting. At both intervals and in both graft-length groups, the grafted bone volume was almost completely preserved inside the scaffolds and exhibited a slight (3 months) to marked (5 months) increase in bone density by appositional bone growth. The inserted screws were histologically integrated into the transplanted bone and the grafts were linked to the adjacent mandibular bone without intervening soft tissue. The grafts, which were transferred to bridge discontinuity defects, were likewise well preserved with direct fusion between the grafted bone and local bone. It was concluded that bone grafts can be prefabricated from underlying mandibular bone and used for the repair of mandibular defects of various length and shape. PMID:9258711

  6. Vapor-deposited amorphous metamaterials as visible near-perfect absorbers with random non-prefabricated metal nanoparticles

    PubMed Central

    Zhang, Yun; Wei, Tiaoxing; Dong, Wenjing; Zhang, Kenan; Sun, Yan; Chen, Xin; Dai, Ning

    2014-01-01

    Spatial order or periodicity is usually required and constructed with tens of nanometers in the feature size, which makes it difficult to process the near-perfect metamaterial absorbers (PMAs) working in the visible range in large-area and mass-production scale. Although many established technologies and theoretical modeling methods used for order-based metamaterials, aperiodic or disordered structures have been gradually recognized to achieve similar functionalities for which the ordered structures are overwhelmingly used. Here, we demonstrated the vapor-deposited ‘amorphous’ metamaterials as controlled-reflectance surfaces and tunable PMAs without the use of the lithographically ordered arrays, the prefabricated colloidal metal nanoparticles (MNPs) or the multilayer of nanoparticles. The flexible construction, the control of the monolayer of MNPs and the atomic-layer-deposited (ALD) dielectric spacer layer provide more insight for understanding the controlled-reflectance surfaces. Such processes have a few key advantages of CMOS-compatible simple processing, low cost and large-area plating, allowing the PMAs to be flexibly constructed in mass-production scale. PMID:24810434

  7. Prefabricated partial distal urethral in 2-staged repair of proximal hypospadias with severe chordee

    PubMed Central

    Fan, Zhi-Qiang; Sun, Jian-Tao; Huangfu, Xue-Hun; Chen, Guo-Xiao; Hao, Jian-Wei; Liu, Zhong-Hua

    2015-01-01

    Purpose: To describe a new technique for staged hypospadias repair in which the urethral plate is divided and tubularized transverse island flap prefabricated partial distal urethral at the time of the first stage. Materials and methods: Sixteen patients with proximal hypospadias associated with severe chordee were operated on using a new staged technique. At the time of the first stage, the urethral plate was divided and chordee was corrected. Then tubularized transverse island flap was used to prefabricate partial distal urethra. The defective urethra was repaired using the Thiersch-Duplay principle at the second stage. Results: All participants have completed both stages of the operation. The mean follow-up duration was 18.4 months (range from 6 to 72 months). In the first-stage surgery, the modified tabularized transverse preputial island flap was performed on 6 patients, whereas the modified preputial double-faced island flap was performed on the other 10 patients. All of the prefabricated partial distal neourethras had no evidence of stenosis or scarring. The result of the second-stage procedure was a complete penis with integrated urethral. All patients were satisfied with cosmetic and functional results. Neither stricture nor diverticula was observed. A good urinary stream during the urination was attained in 12 (75.0%) patients. Four cases (25.0%) developed urethrocutaneous fistula after the second stage repair. Conclusions: In our preliminary series, this procedure improved functional and cosmetic results. It may be applicable to most cases of proximal hypospadias. Even when complications occur, they are less severe compared to those of the traditional staged approach. PMID:25932188

  8. Man as a Living Bioreactor: Prefabrication of a Custom Vascularized Bone Graft in the Gastrocolic Omentum.

    PubMed

    Wiltfang, Jörg; Rohnen, Michael; Egberts, Jan-Hendrik; Lützen, Ulf; Wieker, Henning; Açil, Yahya; Naujokat, Hendrik

    2016-08-01

    Reconstruction of critical-size jaw defects still remains challenging. The standard treatment today is transplantation of autologous bone grafts, which is associated with high donor-site morbidity and unsatisfactory outcomes. We aimed to reconstruct a mandibular discontinuity defect after ablative surgery using the gastrocolic omentum as a bioreactor for heterotopic ossification. Three-dimensional computed tomography data were used to produce an ideal virtual replacement for the mandibular defect. A titanium mesh cage was filled with bone mineral blocks, infiltrated with 12 mg of recombinant human bone morphogenetic protein 2, and enriched with bone marrow aspirate. The scaffold was implanted into the gastrocolic omentum, and 3 months later, a free flap was harvested to reconstruct the mandibular defect. In vivo single photon emission computed tomography/computed tomography revealed bone remodeling and mineralization inside the mandibular transplant during prefabrication and after transplantation. Reconstruction was possible without any further modifications of the graft. A histological evaluation revealed that large sections of the Bio-Oss material were covered with osteoid matrix 3 months after transplantation. The quality of life of the patient significantly increased with acquisition of the ability to masticate and the improvement in pronunciation and aesthetics. Heterotopic bone induction to form a mandibular replacement inside the gastrocolic omentum is possible in human subjects. Heterotopic prefabrication is associated with many advantages, like allowing a reduced operative burden compared with conventional techniques and good three-dimensional outcomes. PMID:27317022

  9. Comparison of custom and prefabricated orthoses in the initial treatment of proximal plantar fasciitis.

    PubMed

    Pfeffer, G; Bacchetti, P; Deland, J; Lewis, A; Anderson, R; Davis, W; Alvarez, R; Brodsky, J; Cooper, P; Frey, C; Herrick, R; Myerson, M; Sammarco, J; Janecki, C; Ross, S; Bowman, M; Smith, R

    1999-04-01

    Fifteen centers for orthopaedic treatment of the foot and ankle participated in a prospective randomized trial to compare several nonoperative treatments for proximal plantar fasciitis (heel pain syndrome). Included were 236 patients (160 women and 76 men) who were 16 years of age or older. Most reported duration of symptoms of 6 months or less. Patients with systemic disease, significant musculoskeletal complaints, sciatica, or local nerve entrapment were excluded. We randomized patients prospectively into five different treatment groups. All groups performed Achilles tendon- and plantar fascia-stretching in a similar manner. One group was treated with stretching only. The other four groups stretched and used one of four different shoe inserts, including a silicone heel pad, a felt pad, a rubber heel cup, or a custom-made polypropylene orthotic device. Patients were reevaluated after 8 weeks of treatment. The percentages improved in each group were: (1) silicone insert, 95%; (2) rubber insert, 88%; (3) felt insert, 81%; (4)stretching only, 72%; and (5) custom orthosis, 68%. Combining all the patients who used a prefabricated insert, we found that their improvement rates were higher than those assigned to stretching only (P = 0.022) and those who stretched and used a custom orthosis (P = 0.0074). We conclude that, when used in conjunction with a stretching program, a prefabricated shoe insert is more likely to produce improvement in symptoms as part of the initial treatment of proximal plantar fasciitis than a custom polypropylene orthotic device. PMID:10229276

  10. Assessment of past exposure to man-made vitreous fibers in the Swedish prefabricated house industry.

    PubMed

    Plato, N; Gustavsson, P; Krantz, S

    1997-10-01

    Large quantities of man-made vitreous fibers (MMVF) are handled in the Swedish prefabricated wooden house industry. The present study is part of a program to investigate mortality, cancer incidence, and current as well as previous exposure to MMVF among workers in the Swedish prefabricated wooden house industry. Since measurements of historical fiber exposure levels are lacking, these were calculated by the application of a matrix of multipliers to recently measured MMVF levels. The multipliers represented changes over time in production rate, technical properties of the fibers, manual handling vs. automation, and ventilation control. The multipliers were based on a similar matrix, developed for the MMVF-manufacturing industry, which was modified to reflect the conditions in the wooden house industry. The model was developed for the highest-exposed job title in the study, insulators. One hundred and twenty samples of airborne fiber were taken in 11 plants to reflect current exposure levels. The highest mean fiber exposure level for insulators was assessed as 0.18 f/ml (geometric mean), which occurred during the mid-1970s, compared to 0.10 f/ml at the end of the 1980s and the early 1960s. Changes in production rate, improved ventilation control, and the surface area of the total amount of MMVF sheets handled per insulator were the most important variables of the model. No increased risk of lung cancer was found in the present industry. PMID:9258388

  11. Case History Report: Immediate Rehabilitation with a Prefabricated Fibula Flap Following Removal of a Locally Aggressive Maxillary Tumor.

    PubMed

    Nkenke, Emeka; Agaimy, Abbas; Vairaktaris, Elefterios; Lell, Michael; von Wilmowsky, Cornelius; Eitner, Stephan

    2016-01-01

    The present clinical case history report describes an interdisciplinary treatment protocol that combines maxillary tumor resection with immediate reconstruction to achieve functional rehabilitation. A fibula flap that received four dental implants and a split-thickness graft epithelial layer was prefabricated for a 31-year-old man. The flap was designed so that it could be adapted to fit in different extents of tumor resection. Resection and immediate reconstruction were successfully performed 6 weeks after flap prefabrication, with the final bar-retained dental prosthesis delivered 4 weeks later. PMID:26757329

  12. A Proposed Collaborative Framework for Prefabricated Housing Construction Using RFID Technology

    NASA Astrophysics Data System (ADS)

    Charnwasununth, Phatsaphan; Yabuki, Nobuyoshi; Tongthong, Tanit

    Despite the popularity of prefabricated housing construction in Thailand and many other countries, due to the lack of collaboration in current practice, undesired low productivity and a number of mistakes are identified. This research proposes a framework to raise the collaborative level for improving productivity and reducing mistake occurrences at sites. In this framework, RFID system bridges the gap between the real situation and the design, and the proposed system can cope with the unexpected construction conditions by generating proper alternatives. This system is composed of PDAs, RFID readers, laptop PCs, and a desktop PC. Six main modules and a database system are implemented in laptop PCs for recording actual site conditions, generating working alternatives, providing related information, and evaluating the work.

  13. [Microorganisms growing on the inner surfaces of prefabricated houses and their control].

    PubMed

    Katircioğlu, Y Z; Gürcan, A

    1987-01-01

    Microorganisms which isolated from the plasters of prefabricated houses, constructed by Yübetaş company in Oran Ankara Were examined. As a result of isolations, Alternaria, Penicillium and Stemphylium species of fungi were founded on the plasters. The growth of the fungi was tested on Agrisan megess and Dyo Sadosan make plastic wall paints and it was found that these fungi showed a profuse growth in the former make paint, but not in the second one. When mancozeb (Dithan-M-45) in 0.2% and copper oxychloride (Mavi Bakir Sandoz) in 0.5% were added to the plaster the growth of the fungi were completely prevented, but Wettable powder sulfur in 0.4% did not prevent their growth but stimulated it. PMID:3441227

  14. [Moisture and mold on the inner walls of prefabricated building slabs--investigating a strange cause].

    PubMed

    Kaufhold, T; Fiedler, K; Jung, G; Lindner, M; Gassel, R P

    1997-04-01

    Reasons for indoor-moisture beyond the normal level can be caused by penetrating dampness, condensation-water, and apartment misuse. A fall in the air temperature below the dew point in connection with moulding inside buildings becomes evident mostly at places like badly insulated outer-walls or room-corners. In a number of houses built between 1980 and 1983 in the so called "Plattenbauweise" (prefabricated slabs), exclusively the inner-walls were covered in mould around cracks in the walls. Examinations showed connections between the apartment and the outer-corridor with a slight exchange of air through the cracks. Warm, wet air escaped from the apartment into the outer-corridor, and cold air entered the apartment from the outer-corridor. This temporary fall below the dewpoint caused by suitable variation of temperature probably resulted in the building materials and wallpapers becoming damp, as well as the growth of mould. PMID:9376065

  15. An ex vivo comparative study on the retention of custom and prefabricated posts

    PubMed Central

    Singh, Abhinav; Logani, Ajay; Shah, Naseem

    2012-01-01

    Aim: This study was designed to comparatively evaluate the effect of cyclic loading on the retention of custom-fabricated fiber-reinforced composite (CF-FRC), prefabricated metal, and glass fiber posts. Materials and Methods: Thirty mandibular first premolars decoronated at the CE junction were divided into three groups (n=10). Groups A, B, and C were restored using Para Post (Whale dent), Reforpost (Angelus), and CF-FRC post (Ribbond-THM), respectively. Five specimens from each group were subjected to cyclic loading. Tensile bond strength (TBS) was evaluated. Results: Pre-loading TBS values were statistically, significantly higher for all posts (P<0.05). Before and after loading, there was a significant difference between group C as compared to groups A and B. Conclusions: Cyclic loading reduced the retention of all posts but was comparatively lesser for the CF-FRC post. This system provides sufficient retention required for clinical success. PMID:22557821

  16. En bloc prefabrication of vascularized bioartificial bone grafts in sheep and complete workflow for custom-made transplants.

    PubMed

    Kokemüller, H; Jehn, P; Spalthoff, S; Essig, H; Tavassol, F; Schumann, P; Andreae, A; Nolte, I; Jagodzinski, M; Gellrich, N-C

    2014-02-01

    The aim of this pilot study was to determine, in a new experimental model, whether complex bioartificial monoblocs of relevant size and stability can be prefabricated in a defined three-dimensional design, in which the latissimus dorsi muscle serves as a natural bioreactor and the thoracodorsal vessel tree is prepared for axial construct perfusion. Eighteen sheep were included in the study, with six animals in each of three experimental groups. Vitalization of the β-tricalcium phosphate-based constructs was performed by direct application of unmodified osteogenic material from the iliac crest (group A), in vivo application of nucleated cell concentrate (NCC) from bone marrow aspirate (group B), and in vitro cultivation of bone marrow stromal cells (BMSC) in a perfusion bioreactor system (group C). The contours of the constructs were designed digitally and transferred onto the bioartificial bone grafts using a titanium cage, which was bent over a stereolithographic model of the defined subvolume intraoperatively. At the end of the prefabrication process, only the axial vascularized constructs of group A demonstrated vital bone formation with considerable stability. In groups B and C, the applied techniques were not able to induce ectopic bone formation. The presented computer-assisted workflow allows the prefabrication of custom-made bioartificial transplants. PMID:24238866

  17. Effect of eugenol-based root canal sealers on retention of prefabricated metal posts luted with resin cement

    PubMed Central

    Al-Ali, Khalil

    2009-01-01

    Objective This study evaluated the effect of two different eugenol-based root canal sealers on the retention of prefabricated metal posts luted with adhesive resin cement. Materials and methods Thirty prefabricated ParaPosts randomly divided among three groups of 10 each were luted into extracted single-rooted teeth with adhesive resin cement. Two of the groups had been obturated with Gutta–Percha and one of two eugenol-based root canal sealers (Endofil and Tubli-Seal), respectively. The third group was not obturated and served as the control. The forces required for dislodgment of posts from their prepared post spaces were recorded using a universal testing machine. Data were statistically analyzed using one-way ANOVA and Tukey’s multiple range test was used to determine the mean differences. Results Endofil and Tubli-Seal groups demonstrated significantly reduced retention compared to the unobturated (control) group (P < 0.05). Conclusion Eugenol-based sealers significantly reduced the retention of prefabricated posts luted with adhesive resin cement. PMID:23960462

  18. The effect of a prefabricated foot orthotic on frontal plane joint mechanics in healthy runners.

    PubMed

    Almonroeder, Thomas G; Benson, Lauren C; O'Connor, Kristian M

    2015-06-01

    The mechanism of action of a foot orthotic is poorly understood. The purpose of this study was to use principal components analysis (PCA) to analyze the effects of a prefabricated foot orthotic on frontal plane knee and ankle mechanics during running. Thirty-one healthy subjects performed running trials with and without a foot orthotic and PCA was performed on the knee and ankle joint angles and moments to identify the dominant modes of variation. MANOVAs were conducted on the retained principal components of each waveform and dependent t tests (P < .05) were performed in the case of significance. Mechanics of the ankle were not affected by the foot orthotic. However, mechanics of the knee were significantly altered as subjects demonstrated an increase in the magnitude of the knee abduction moment waveform in an orthotic condition. Subjects also demonstrated a significant shift in the timing of the knee abduction moment waveform toward later in the stance phase in the orthotic condition. These orthotic effects were not related to subject's foot mobility, measured using the navicular drop test. The mechanism of action of a foot orthotic may be related to their effect on the timing of frontal plane knee loading. PMID:25536274

  19. Implant-supported overdenture with prefabricated bar attachment system in mandibular edentulous patient

    PubMed Central

    Ha, Seung-Ryong; Song, Seung-Il; Hong, Seong-Tae; Kim, Gy-Young

    2012-01-01

    Implant-supported overdenture is a reliable treatment option for the patients with edentulous mandible when they have difficulty in using complete dentures. Several options have been used for implant-supported overdenture attachments. Among these, bar attachment system has greater retention and better maintainability than others. SFI-Bar® is prefabricated and can be adjustable at chairside. Therefore, laboratory procedures such as soldering and welding are unnecessary, which leads to fewer errors and lower costs. A 67-year-old female patient presented, complaining of mobility of lower anterior teeth with old denture. She had been wearing complete denture in the maxilla and removable partial denture in the mandible with severe bone loss. After extracting the teeth, two implants were placed in front of mental foramen, and SFI-Bar® was connected. A tube bar was seated to two adapters through large ball joints and fixation screws, connecting each implant. The length of the tube bar was adjusted according to inter-implant distance. Then, a female part was attached to the bar beneath the new denture. This clinical report describes two-implant-supported overdenture using the SFI-Bar® system in a mandibular edentulous patient. PMID:23236580

  20. Hospital-wide outbreak of Burkholderia contaminans caused by prefabricated moist washcloths.

    PubMed

    Martin, M; Christiansen, B; Caspari, G; Hogardt, M; von Thomsen, A J; Ott, E; Mattner, F

    2011-03-01

    We experienced a hospital outbreak of Burkholderia contaminans (Burkholderia cepacia Group K) in a German university hospital with two campuses. Cases were defined as the microbiological detection of B. cepacia complex (BCC) in any clinical specimen sent to the laboratory during 30 June to 21 October 2008. Species identification of BCC was performed by recA gene sequencing, followed by pulsed-field gel electrophoresis (PFGE; SpeI digest) for clonal identity. In total, 61 BCC-positive cases were diagnosed at the two campuses. At least nine patients contracted a ventilator-associated pneumonia with BCC. One patient suffered an infection of a pacing wire insertion site and four patients had septicaemia. Sixteen patients died in hospital, none thought to be due to the outbreak strain. BCC was eventually found in packages of moist prefabricated washcloths used for intensive care patients. German healthcare authorities were informed and a Europe-wide alarm (RAPEX) was initiated through the systems to prevent infections in other hospitals. PFGE proved clonal identity between isolates from clinical specimens and washcloths of both campuses. After elimination of the contaminated washcloths no further cases occurred. This example of a relatively newly introduced product raises the question of whether current regulations are adequate to protect consumers. For critically ill patients, care products should be carefully evaluated. In case of infections due to contaminated products, immediate communication to healthcare authorities is required, including RAPEX warning if products are sold across Europe. PMID:21216034

  1. Effect of cyclic load on vertical misfit of prefabricated and cast implant single abutment

    PubMed Central

    DE JESUS TAVAREZ, Rudys Rodolfo; BONACHELA, Wellington Cardoso; XIBLE, Anuar Antônio

    2011-01-01

    Objective The purpose of this in vitro study was to evaluate misfit alterations at the implant/abutment interface of external and internal connection implant systems when subjected to cyclic loading. Material and Methods Standard metal crowns were fabricated for 5 groups (n=10) of implant/abutment assemblies: Group 1, external hexagon implant and UCLA cast-on premachined abutment; Group 2, internal hexagon implant and premachined abutment; Group 3, internal octagon implant and prefabricated abutment; Group 4, external hexagon implant and UCLA cast-on premachined abutment; and Group 5, external hexagon implant and Ceraone abutment. For groups 1, 2, 3 and 5, the crowns were cemented on the abutments and in group 4 crowns were screwed directly on the implant. The specimens were subjected to 500,000 cycles at 19.1 Hz of frequency and non-axial load of 133 N in a MTS 810 machine. The vertical misfit (μm) at the implant/abutment interface was evaluated before (B) and after (A) application of the cyclic loading. Data were analyzed statistically by using two-away ANOVA and Tukey’s post-hoc test (p<0.05). Results Before loading values showed no difference among groups 2 (4.33±3.13), 3 (4.79±3.43) and 5 (3.86±4.60); between groups 1 (12.88±6.43) and 4 (9.67±3.08), and among groups 2, 3 and 4. However, groups 1 and 4 were significantly different from groups 2, 3 and 5. After loading values of groups 1 (17.28±8.77) and 4 (17.78±10.99) were significantly different from those of groups 2 (4.83±4.50), 3 (8.07±4.31) and 5 (3.81±4.84). There was a significant increase in misfit values of groups 1, 3 and 4 after cyclic loading, but not for groups 2 and 5. Conclusion The cyclic loading and type of implant/abutment connection may develop a role on the vertical misfit at the implant/abutment interface. PMID:21437464

  2. Evaluation of Columbia, USMARC-Composite, Suffolk, and Texel rams as terminal sires in an extensive rangeland production system: III. Prefabrication carcass traits and organ

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To evaluate terminal sire breeds, harvest BW, prefabrication carcass measurements, and organ weights were evaluated over 3 yr, for 518 crossbred wether lambs. Lambs were produced by single-sire matings of 22 Columbia, 22 USMARC-Composite (Composite), 21 Suffolk, and 17 Texel rams to adult Rambouille...

  3. Lung cancer risk among workers exposed to man-made mineral fibers (MMMF) in the Swedish prefabricated house industry.

    PubMed

    Gustavsson, P; Plato, N; Axelson, O; Brage, H N; Hogstedt, C; Ringbäck, G; Tornling, G; Wingren, G

    1992-01-01

    Mortality and cancer incidence was investigated among 2,807 workers, employed for at least one year before 1972, at 11 Swedish companies manufacturing prefabricated wooden houses. A total of 1,068 workers had been exposed to man-made mineral fibers (MMMF) used for insulation. Mortality was followed from 1969 to 1988 and cancer incidence from 1969 to 1985. Exposure conditions were investigated at all plants. There were 14 deaths from lung cancer in the total cohort, whereas 20.7 would be expected (SMR = 68; 95% CI:37-113), based on regional mortality. After a latency of 20 years of more, two lung cancer cases had occurred among all workers exposed to MMMF, whereas 4.3 would be expected (SMR = 46; 95% CI: 5-168). The exposure levels that have prevailed do not seem to be associated with an increased lung cancer rate, but extended follow-up is necessary for a definitive evaluation. PMID:1621690

  4. Adhesion promoters for large scale fabrication of dielectric elastomer stack transducers (DESTs) made of pre-fabricated dielectric films

    NASA Astrophysics Data System (ADS)

    Grotepaß, T.; Förster-Zügel, F.; Mößinger, H.; Schlaak, H. F.

    2015-04-01

    Multilayer dielectric elastomer stack transducers (DESTs) are a promising new transducer technology with many applications in different industry sectors, like medical devices, human-machine-interaction, etc. Stacked dielectric elastomer transducers show larger thickness contraction driven by lower voltages than transducers made from a single dielectric layer. Traditionally multilayered DESTs are produced by repeatedly cross-linking a liquid elastomeric pre-polymer into the required shape. Our recent research focusses on a novel fabrication method for large scale stack transducers with a surface area over 200 x 300 mm by processing pre-fabricated elastomeric thin films of less than 50 μm thicknesses. The thin films are provided as two- or three-layer composites, where the elastomer is sandwiched between one or two sacrificial liners. Separating the elastomeric film from the residual layers and assembling them into dielectric elastomer stack transducers poses many challenges concerning adhesion, since the dielectric film merely separates from the liner if the adhesive forces between them are overcome. Conversely, during the assembly of a dielectric elastomer stack transducer, adhesive forces have to be established between two elastomeric layers or between the dielectric and the electrode layer. The very low Young's modulus of at least one adhesion partner requires suitable means of increasing the adhesive forces between the different adhesive layers of a dielectric elastomer stack transducer to prevent a delamination of the transducer during its lifetime. This work evaluates different surface activation treatments - corona, low-pressure plasma and UV-light - and their applicability in the production of large scale DESTs made from pre-fabricated elastomeric films.

  5. Spatial and temporal patterns of bone formation in ectopically pre-fabricated, autologous cell-based engineered bone flaps in rabbits

    PubMed Central

    Scheufler, Oliver; Schaefer, Dirk J; Jaquiery, Claude; Braccini, Alessandra; Wendt, David J; Gasser, Jürg A; Galli, Raffaele; Pierer, Gerhard; Heberer, Michael; Martin, Ivan

    2008-01-01

    Biological substitutes for autologous bone flaps could be generated by combining flap pre-fabrication and bone tissue engineering concepts. Here, we investigated the pattern of neotissue formation within large pre-fabricated engineered bone flaps in rabbits. Bone marrow stromal cells from 12 New Zealand White rabbits were expanded and uniformly seeded in porous hydroxyapatite scaffolds (tapered cylinders, 10–20 mm diameter, 30 mm height) using a perfusion bioreactor. Autologous cell-scaffold constructs were wrapped in a panniculus carnosus flap, covered by a semipermeable membrane and ectopically implanted. Histological analysis, substantiated by magnetic resonance imaging (MRI) and micro-computerized tomography scans, indicated three distinct zones: an outer one, including bone tissue; a middle zone, formed by fibrous connective tissue; and a central zone, essentially necrotic. The depths of connective tissue and of bone ingrowth were consistent at different construct diameters and significantly increased from respectively 3.1 ± 0.7 mm and 1.0 ± 0.4 mm at 8 weeks to 3.7± 0.6 mm and 1.4 ± 0.6 mm at 12 weeks. Bone formation was found at a maximum depth of 1.8 mm after 12 weeks. Our findings indicate the feasibility of ectopic pre-fabrication of large cell-based engineered bone flaps and prompt for the implementation of strategies to improve construct vascularization, in order to possibly accelerate bone formation towards the core of the grafts. PMID:18782188

  6. Follow-up of workers from the prefabricated concrete industry after the addition of ferrous sulphate to Danish cement.

    PubMed

    Avnstorp, C

    1989-05-01

    Ferrous sulfate has been added to cement manufactured in Denmark, reducing the water soluble chromate content to not more than 2 ppm, since September 1981. A comparison is made between the medical and employment status of a cohort of workers engaged, or who had been engaged, in the manufacture of prefabricated concrete building components in 1981 and in 1987. Workers who had allergic cement eczema in 1981 appeared to show no improvement 6 years after the reduction of chromate in the cement. Improvement was seen, however, in the eczema of those workers with irritant cement eczema. The 1987 study showed that a larger number of chromate-sensitized workers required medical services and topical steroid treatment than did those who were not sensitized to chromate. This difference was statistically significant. The worse medical prognosis of the chromate-sensitized workers could in part be due to the fact that some of these had secondary contact sensitivity to cobalt and rubber chemicals. The chromate-sensitized workers also took earlier retirement. Younger workers with allergic and irritant cement eczema continued to work and their employment status was not influenced by chromate sensitization. PMID:2527716

  7. Angiographic Evaluation of Carotid Artery Grafting with Prefabricated Small-Diameter, Small-Intestinal Submucosa Grafts in Sheep

    SciTech Connect

    Pavcnik, Dusan; Obermiller, Josef; Uchida, Barry T.; Van Alstine, William; Edwards, James M.; Landry, Gregory J.; Kaufman, John A.; Keller, Frederick S.; Roesch, Josef

    2009-01-15

    The purpose of this study was to report the longitudinal angiographic evaluation of prefabricated lyophilized small-intestinal submucosa (SIS) grafts placed in ovine carotid arteries and to demonstrate a variety of complications that developed. A total of 24 grafts, 10 cm long and 6 mm in diameter, were placed surgically as interposition grafts. Graft patency at 1 week was evaluated by Doppler ultrasound, and angiography was used for follow-up at 1 month and at 3 to 4 months. A 90% patency rate was found at 1 week, 65% at 1 month, and 30% at 3 to 4 months. On the patent grafts, angiography demonstrated a variety of changes, such as anastomotic stenoses, graft diffuse dilations and dissections, and aneurysm formation. These findings have not been previously demonstrated angiographically by other investigators reporting results with small-diameter vessel grafts made from fresh small-intestinal submucosa (SIS). The complications found were partially related to the graft construction from four SIS layers. Detailed longitudinal angiographic study should become an essential part of any future evaluation of small-vessel SIS grafting.

  8. The Influence of a Prefabricated Foot Orthosis on Lower Extremity Mechanics During Running in Individuals With Varying Dynamic Foot Motion.

    PubMed

    Almonroeder, Thomas G; Benson, Lauren C; O'Connor, Kristian M

    2016-09-01

    Study Design Controlled laboratory study, cross-sectional. Background Orthotic prescription is often based on the premise that the mechanical effects will be more prominent in individuals with greater calcaneal eversion. Objective To compare the effects of a prefabricated foot orthosis on lower extremity kinematics and kinetics between recreational athletes with high and low calcaneal eversion during running. Methods Thirty-one recreational athletes were included in this study. Three-dimensional kinematic and kinetic data were collected while running with and without a foot orthosis. Participants were grouped based on the degree of calcaneal eversion during the running trials relative to a standing trial (dynamic foot motion). The effects of the orthosis on the frontal and transverse plane angles and moments of the hip and knee were compared between the 10 participants with the greatest and least amount of dynamic foot motion. Results There were no significant interactions (group by orthotic condition) for any of the kinematic or kinetic variables of interest. Conclusion The effects of an orthosis on the mechanics of the hip and knee do not appear to be dependent on an individual's dynamic foot motion. J Orthop Sports Phys Ther 2016;46(9):749-755. Epub 5 Aug 2016. doi:10.2519/jospt.2016.6253. PMID:27494054

  9. Supporting Structures for Flat Solar-Cell Arrays

    NASA Technical Reports Server (NTRS)

    Wilson, A. H.

    1986-01-01

    Strong supporting structures for flat solar photovoltaic arrays built with such commonly available materials as wood and galvanized steel sheet. Structures resist expected static loads from snow and ice as well as dynamic loads from winds and even Earthquake vibrations. Supporting structure uses inexpensive materials. Parts prefabricated to minimize assembly work in field.

  10. A comparison of customised and prefabricated insoles to reduce risk factors for neuropathic diabetic foot ulceration: a participant-blinded randomised controlled trial

    PubMed Central

    2012-01-01

    Background Neuropathic diabetic foot ulceration may be prevented if the mechanical stress transmitted to the plantar tissues is reduced. Insole therapy is one practical method commonly used to reduce plantar loads and ulceration risk. The type of insole best suited to achieve this is unknown. This trial compared custom-made functional insoles with prefabricated insoles to reduce risk factors for ulceration of neuropathic diabetic feet. Method A participant-blinded randomised controlled trial recruited 119 neuropathic participants with diabetes who were randomly allocated to custom-made functional or prefabricated insoles. Data were collected at issue and six month follow-up using the F-scan in-shoe pressure measurement system. Primary outcomes were: peak pressure, forefoot pressure time integral, total contact area, forefoot rate of load, duration of load as a percentage of stance. Secondary outcomes were patient perceived foot health (Bristol Foot Score), quality of life (Audit of Diabetes Dependent Quality of Life). We also assessed cost of supply and fitting. Analysis was by intention-to-treat. Results There were no differences between insoles in peak pressure, or three of the other four kinetic measures. The custom-made functional insole was slightly more effective than the prefabricated insole in reducing forefoot pressure time integral at issue (27% vs. 22%), remained more effective at six month follow-up (30% vs. 24%, p=0.001), but was more expensive (UK £656 vs. £554, p<0.001). Full compliance (minimum wear 7 hours a day 7 days per week) was reported by 40% of participants and 76% of participants reported a minimum wear of 5 hours a day 5 days per week. There was no difference in patient perception between insoles. Conclusion The custom-made insoles are more expensive than prefabricated insoles evaluated in this trial and no better in reducing peak pressure. We recommend that where clinically appropriate, the more cost effective prefabricated insole

  11. Graphene-based structure, method of suspending graphene membrane, and method of depositing material onto graphene membrane

    DOEpatents

    Zettl, Alexander K.; Meyer, Jannik Christian

    2013-04-02

    An embodiment of a method of suspending a graphene membrane across a gap in a support structure includes attaching graphene to a substrate. A pre-fabricated support structure having the gap is attached to the graphene. The graphene and the pre-fabricated support structure are then separated from the substrate which leaves the graphene membrane suspended across the gap in the pre-fabricated support structure. An embodiment of a method of depositing material includes placing a support structure having a graphene membrane suspended across a gap under vacuum. A precursor is adsorbed to a surface of the graphene membrane. A portion of the graphene membrane is exposed to a focused electron beam which deposits a material from the precursor onto the graphene membrane. An embodiment of a graphene-based structure includes a support structure having a gap, a graphene membrane suspended across the gap, and a material deposited in a pattern on the graphene membrane.

  12. An assessment of fracture resistance of three composite resin core build-up materials on three prefabricated non-metallic posts, cemented in endodontically treated teeth: an in vitro study

    PubMed Central

    Pal, Bhupinder; Pujari, Prashant

    2015-01-01

    Endodontically treated teeth with excessive loss of tooth structure would require to be restored with post and core to enhance the strength and durability of the tooth and to achieve retention for the restoration. The non-metallic posts have a superior aesthetic quality. Various core build-up materials can be used to build-up cores on the posts placed in endodontically treated teeth. These materials would show variation in their bonding with the non-metallic posts thus affecting the strength and resistance to fracture of the remaining tooth structure. Aims. The aim of the study was to assess the fracture resistance of three composite resin core build-up materials on three prefabricated non-metallic posts, cemented in extracted endodontically treated teeth. Material and Methods. Forty-five freshly extracted maxillary central incisors of approximately of the same size and shape were selected for the study. They were divided randomly into 3 groups of 15 each, depending on the types of non-metallic posts used. Each group was further divided into 3 groups (A, B and C) of 5 samples each depending on three core build-up material used. Student’s unpaired ‘t’ test was also used to analyse and compare each group with the other groups individually, and decide whether their comparisons were statistically significant. Results. Luxacore showed the highest fracture resistance among the three core build-up materials with all the three posts systems. Ti-core had intermediate values of fracture resistance and Lumiglass had the least values of fracture resistance. PMID:25755926

  13. Rocker-sole footwear versus prefabricated foot orthoses for the treatment of pain associated with first metatarsophalangeal joint osteoarthritis: study protocol for a randomised trial

    PubMed Central

    2014-01-01

    Background Osteoarthritis affecting the first metatarsophalangeal joint of the foot is a common condition which results in pain, stiffness and impaired ambulation. Footwear modifications and foot orthoses are widely used in clinical practice to treat this condition, but their effectiveness has not been rigorously evaluated. This article describes the design of a randomised trial comparing the effectiveness of rocker-sole footwear and individualised prefabricated foot orthoses in reducing pain associated with first metatarsophalangeal joint osteoarthritis. Methods Eighty people with first metatarsophalangeal joint osteoarthritis will be randomly allocated to receive either a pair of rocker-sole shoes (MBT® Matwa, Masai Barefoot Technology, Switzerland) or a pair of individualised, prefabricated foot orthoses (Vasyli Customs, Vasyli Medical™, Queensland, Australia). At baseline, the biomechanical effects of the interventions will be examined using a wireless wearable sensor motion analysis system (LEGSys™, BioSensics, Boston, MA, USA) and an in-shoe plantar pressure system (Pedar®, Novel GmbH, Munich, Germany). The primary outcome measure will be the pain subscale of the Foot Health Status Questionnaire (FHSQ), measured at baseline and 4, 8 and 12 weeks. Secondary outcome measures will include the function, footwear and general foot health subscales of the FHSQ, severity of pain and stiffness at the first metatarsophalangeal joint (measured using 100 mm visual analog scales), global change in symptoms (using a 15-point Likert scale), health status (using the Short-Form-12® Version 2.0 questionnaire), use of rescue medication and co-interventions to relieve pain, the frequency and type of self-reported adverse events and physical activity levels (using the Incidental and Planned Activity Questionnaire). Data will be analysed using the intention to treat principle. Discussion This study is the first randomised trial to compare the effectiveness of rocker

  14. The Value of SPECT/CT in Monitoring Prefabricated Tissue-Engineered Bone and Orthotopic rhBMP-2 Implants for Mandibular Reconstruction.

    PubMed

    Zhou, Miao; Peng, Xin; Mao, Chi; Tian, Jia-he; Zhang, Shu-wen; Xu, Fang; Tu, Jing-jing; Liu, Sheng; Hu, Min; Yu, Guang-yan

    2015-01-01

    Bone tissue engineering shows good prospects for mandibular reconstruction. In recent studies, prefabricated tissue-engineered bone (PTEB) by recombinant human bone morphogenetic proteins (rhBMPs) applied in vivo has found to be an effective alternative for autologous bone grafts. However, the optimal time to transfer PTEB for mandibular reconstruction is still not elucidated. Thus, here in an animal experiment of rhesus monkey, the suitable transferring time for PTEB to reconstruct mandibular defects was evaluated by 99mTc-MDP SPECT/CT, and its value in monitoring orthotopic rhBMP-2 implants for mandibular reconstruction was also evaluated. The result of SPECT/CT showed higher 99mTc-MDP uptake, indicating osteoinductivity, in rhBMP-2 incorporated demineralized freeze-dried bone allograft (DFDBA) and coralline hydroxyapatite (CHA) implants than those without BMP stimulation. 99mTc-MDP uptake of rhBMP-2 implant peaked at 8 weeks following implantation while CT showed the density of these implants increased after 13 weeks' prefabrication. Histology confirmed that mandibular defects were repaired successfully with PTEB or orthotopically rhBMP-2 incorporated CHA implants, in accordance with SPECT/CT findings. Collectively, data shows 99mTc-MDP SPECT/CT is a sensitive and noninvasive tool to monitor osteoinductivity and bone regeneration of PTEB and orthotopic implants. The PTEB achieved peak osteoinductivity and bone density at 8 to 13 weeks following ectopic implantation, which would serve as a recommendable time frame for its transfer to mandibular reconstruction. PMID:26340447

  15. The Value of SPECT/CT in Monitoring Prefabricated Tissue-Engineered Bone and Orthotopic rhBMP-2 Implants for Mandibular Reconstruction

    PubMed Central

    Zhou, Miao; Peng, Xin; Mao, Chi; Tian, Jia-he; Zhang, Shu-wen; Xu, Fang; Tu, Jing-jing; Liu, Sheng; Hu, Min; Yu, Guang-yan

    2015-01-01

    Bone tissue engineering shows good prospects for mandibular reconstruction. In recent studies, prefabricated tissue-engineered bone (PTEB) by recombinant human bone morphogenetic proteins (rhBMPs) applied in vivo has found to be an effective alternative for autologous bone grafts. However, the optimal time to transfer PTEB for mandibular reconstruction is still not elucidated. Thus, here in an animal experiment of rhesus monkey, the suitable transferring time for PTEB to reconstruct mandibular defects was evaluated by 99mTc-MDP SPECT/CT, and its value in monitoring orthotopic rhBMP-2 implants for mandibular reconstruction was also evaluated. The result of SPECT/CT showed higher 99mTc-MDP uptake, indicating osteoinductivity, in rhBMP-2 incorporated demineralized freeze-dried bone allograft (DFDBA) and coralline hydroxyapatite (CHA) implants than those without BMP stimulation. 99mTc-MDP uptake of rhBMP-2 implant peaked at 8 weeks following implantation while CT showed the density of these implants increased after 13 weeks’ prefabrication. Histology confirmed that mandibular defects were repaired successfully with PTEB or orthotopically rhBMP-2 incorporated CHA implants, in accordance with SPECT/CT findings. Collectively, data shows 99mTc-MDP SPECT/CT is a sensitive and noninvasive tool to monitor osteoinductivity and bone regeneration of PTEB and orthotopic implants. The PTEB achieved peak osteoinductivity and bone density at 8 to 13 weeks following ectopic implantation, which would serve as a recommendable time frame for its transfer to mandibular reconstruction. PMID:26340447

  16. Enhanced room-temperature thermoelectric performance of In-doped ZnO:Al thin films through prefabricated layer doping method

    NASA Astrophysics Data System (ADS)

    Zheng, Zhuang-Hao; Fan, Ping; Luo, Jing-Ting; Liang, Guang-Xing; Zhang, Dong-Ping

    2015-05-01

    In this study, AZO thin films prepared by direct current reactive magnetron sputtering using a Zn-Al alloy target and In with varied content were doped through the prefabricated layer doping method in order to optimize their thermoelectric properties. The effects of In content on the room temperature microstructure and thermoelectric properties of the AZO thin films were investigated. It was found that the absolute value of the Seebeck coefficient of the thin films increases stably after In doping and reaches 153 μV·K-1 when the In content is 0.71%. Though the electrical conductivity of In-doped thin films is smaller than those of the un-doped films, the power factor of the thin films shows a significant increase after In doping with a maximum value of 2.22 × 10-4 W·m-1·K-2, which is several times that of the un-doped films.[Figure not available: see fulltext.

  17. The benefits of an additional worker are task-dependent: assessing low-back injury risks during prefabricated (panelized) wall construction.

    PubMed

    Kim, Sunwook; Nussbaum, Maury A; Jia, Bochen

    2012-09-01

    Team manual material handling is a common practice in residential construction where prefabricated building components (e.g., wall panels) are increasingly used. As part of a larger effort to enable proactive control of ergonomic exposures among workers handling panels, this study explored the effects of additional workers on injury risks during team-based panel erection tasks, specifically by quantifying how injury risks are affected by increasing the number of workers (by one, above the nominal or most common number). Twenty-four participants completed panel erection tasks with and without an additional worker under different panel mass and size conditions. Four risk assessment methods were employed that emphasized the low back. Though including an additional worker generally reduced injury risk across several panel masses and sizes, the magnitude of these benefits varied depending on the specific task and exhibited somewhat high variability within a given task. These results suggest that a simple, generalizable recommendation regarding team-based panel erection tasks is not warranted. Rather, a more systems-level approach accounting for both injury risk and productivity (a strength of panelized wall systems) should be undertaken. PMID:22226545

  18. Mandibular reconstruction with a prefabricated free vascularized fibula and implant-supported prosthesis based on fully three-dimensional virtual planning.

    PubMed

    Freudlsperger, Christian; Bodem, Jens Philipp; Engel, Eva; Hoffmann, Jürgen

    2014-05-01

    Because optimal reconstruction of maxillofacial defects requires functional rehabilitation, the current study demonstrates the successful secondary reconstruction of a large mandibular continuity defect using a fully digitally planned prefabricated free vascularized fibula with immediate implant-supported prosthodontic restoration. A 56-year-old man presented with a large mandibular continuity defect after resection of an enlarged squamous cell carcinoma arising from the floor of the mouth. For secondary reconstruction, the shape of the neomandible and implant position for support of the lower prosthesis were planned virtually. The combined cutting and drilling guide was printed in 3 dimensions. In a 2-step surgical approach, first, the implants were inserted into the fibula and covered with a split-thickness skin graft to form a neogingiva. In a second operation, the fibula was harvested, osteotomized, and fixed with the denture on the preinserted implants. The fibula was placed to its final position guided by the occlusion. Using three-dimensional virtual backward planning, it was feasible to perform a mandibular reconstruction with immediate prosthetic rehabilitation. PMID:24670276

  19. Integrated reactive ion etching to pattern cross-linked hydrophilic polymer structures for protein immobilization

    NASA Astrophysics Data System (ADS)

    Bhatnagar, Parijat; Strickland, Aaron D.; Kim, Il; Malliaras, George G.; Batt, Carl A.

    2007-04-01

    Patterning of cross-linked hydrophilic polymer features using reactive ion etching (RIE) capable of covalently immobilizing proteins has been achieved. Projection photolithography was used to pattern photoresist to create micromolds. Vapor phase molecular self-assembly of polymerizable monolayer in molds allowed covalent binding of hydrogel on surface during free-radical polymerization. Excess hydrogel blanket film was consumed with oxygen RIE resulting into hydrogel pattern of 1μm size aligned to prefabricated silicon oxide structures. Proteins were finally coupled through their primary amine groups selectively to acid functionalized hydrogel features through stable amide linkages using 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride and N-hydroxysulfosuccinimide.

  20. Structuralism.

    ERIC Educational Resources Information Center

    Piaget, Jean

    Provided is an overview of the analytical method known as structuralism. The first chapter discusses the three key components of the concept of a structure: the view of a system as a whole instead of so many parts; the study of the transformations in the system; and the fact that these transformations never lead beyond the system but always…

  1. Rapid production of structural color images with optical data storage capabilities

    NASA Astrophysics Data System (ADS)

    Rezaei, Mohamad; Jiang, Hao; Qarehbaghi, Reza; Naghshineh, Mohammad; Kaminska, Bozena

    2015-03-01

    In this paper, we present novel methods to produce structural color image for any given color picture using a pixelated generic stamp named nanosubstrate. The nanosubstrate is composed of prefabricated arrays of red, green and blue subpixels. Each subpixel has nano-gratings and/or sub-wavelength structures which give structural colors through light diffraction. Micro-patterning techniques were implemented to produce the color images from the nanosubstrate by selective activation of subpixels. The nano-grating structures can be nanohole arrays, which after replication are converted to nanopillar arrays or vice versa. It has been demonstrated that visible and invisible data can be easily stored using these fabrication methods and the information can be easily read. Therefore the techniques can be employed to produce personalized and customized color images for applications in optical document security and publicity, and can also be complemented by combined optical data storage capabilities.

  2. Mimicking bicolor by changing the reflectance of the substrate in a one-dimensional periodic structure.

    PubMed

    Wang, Bin; Ye, Yong-Hong; Yang, Li

    2013-11-01

    In nature, some beetles can display bicolor on their elytra. In order to explore the bicolor mechanism, we experimentally studied the optical and structural properties of the Carabus lafossei beetle. We found a multilayer structure in the cuticle of the beetle. Due to the different multilayer thicknesses in different areas, the beetle displayed bicolor. Here, we provide another approach to fabricate bicolor by depositing the same multilayer stack on a substrate with different reflectances at different areas. In this paper, the substrate with different reflectances is achieved by prefabricating sculpted hexagons (SU-8) on a silicon substrate. By coating a (ZnS/MgF2)3.5 multilayer, the sculpted structure displays green color at the ridges (SU-8/silicon area) and yellow color at the basins (silicon area). PMID:24216662

  3. Advanced Metal Foam Structures for Outer Space

    NASA Technical Reports Server (NTRS)

    Hanan, Jay; Johnson, William; Peker, Atakan

    2005-01-01

    A document discusses a proposal to use advanced materials especially bulk metallic glass (BMG) foams in structural components of spacecraft, lunar habitats, and the like. BMG foams, which are already used on Earth in some consumer products, are superior to conventional metal foams: BMG foams have exceptionally low mass densities and high strength-to-weight ratios and are more readily processable into strong, lightweight objects of various sizes and shapes. These and other attractive properties of BMG foams would be exploited, according to the proposal, to enable in situ processing of BMG foams for erecting and repairing panels, shells, containers, and other objects. The in situ processing could include (1) generation of BMG foams inside prefabricated deployable skins that would define the sizes and shapes of the objects thus formed and (2) thermoplastic deformation of BMG foams. Typically, the generation of BMG foams would involve mixtures of precursor chemicals that would be subjected to suitable pressure and temperature schedules. In addition to serving as structural components, objects containing or consisting of BMG foams could perform such functions as thermal management, shielding against radiation, and shielding against hypervelocity impacts of micrometeors and small debris particles.

  4. Evaluation of pre-fabricated root canal posts.

    PubMed

    Hew, Y S; Purton, D G; Love, R M

    2001-03-01

    In this in vitro study, properties of a titanium alloy post recently introduced to the market (IntegraPost), were compared with those of a clinically proven stainless steel post (ParaPost). The IntegraPost has a unique, perforated, spherical head and a microknurled shank surface. The posts were tested for rigidity, for retention within the root canals of extracted teeth and for ability to retain composite resin cores. The two post types exhibited similar properties in core and root canal retention, however, the IntegraPost was significantly less rigid than the ParaPost. PMID:11350574

  5. Prefabricated heat-exchanging fireplace. Final technical report

    SciTech Connect

    Schleper, M.A.

    1981-06-15

    A heat-exchanging fireplace was installed in a 2000 square foot home and the standard air distribution equipment was ducted directly to the forced-air heating system of the home. The standard air distribution equipment for the fireplace included two squirrel-cage blowers which were connected to a thermostat, allowing a choice of temperature ranges; and a snap disc thermostat was used to disconnect the blowers in order to avoid blowing cold air after the fire died out. Arranged in this manner, one is able to set the regular home thermostat a few degrees lower than the fireplace thermostat, and this will allow the regular heating system to turn on after the fire has gone out in the fireplace. Energy consumption in both the fireplace and the conventional heating system was monitored throughout a heating season and then compared with past heating seasons when only a conventional heating system was used.

  6. Faxing Structures to the Moon: Freeform Additive Construction System (FACS)

    NASA Technical Reports Server (NTRS)

    Howe, A. Scott; Wilcox, Brian; McQuin, Christopher; Townsend, Julie; Rieber, Richard; Barmatz, Martin; Leichty, John

    2013-01-01

    Using the highly articulated All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) robotic mobility system as a precision positioning tool, a variety of print head technologies can be used to 3D print large-scale in-situ structures on planetary surfaces such as the moon or Mars. In effect, in the same way CAD models can be printed in a 3D printer, large-scale structures such as walls, vaults, domes, berms, paving, trench walls, and other insitu derived elements can be FAXed to the planetary surface and built in advance of the arrival of crews, supplementing equipment and materials brought from earth. This paper discusses the ATHLETE system as a mobility / positioning platform, and presents several options for large-scale additive print head technologies, including tunable microwave "sinterator" approaches and in-situ concrete deposition. The paper also discusses potential applications, such as sintered-in-place habitat shells, radiation shielding, road paving, modular bricks, and prefabricated construction components.

  7. Technical challenges in the design and construction of the Troll gravity base structure

    SciTech Connect

    Skjaeveland, H.; Knudsen, A.; Nyborg, A.

    1994-12-31

    The Troll gravity base structure (GBS), which currently is under construction, is the largest and tallest offshore concrete structure yet. The platform concept has several novel features. In order to reduce the wave loads from the substructure into the deck frame, a flexible deck connection is used for 2 of the 4 shafts. The Riegel structure at mid height is a new way of reducing the loads in the shafts and the natural periods of the structure. The platform location in the North Sea has some very soft layers of clay. To overcome the poor foundation condition, very deep skirt piles will be used. The Wave phenomenon, dynamic transient response, ringing has been addressed, both through model testing and analytical work. The enormous height of the concrete structure, over 370 meter has been a substantial construction challenge. In order to meet a very tight construction program, innovative methods of prefabrication have been used. In order to optimize the weight and stability of the structure during the floating phases, various concrete densities and strengths have been used.

  8. 41 CFR 102-39.60 - What restrictions and prohibitions apply to the exchange/sale of personal property?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 1560 Airframe Structural Components). 42 Firefighting, rescue, and safety equipment. 44 Nuclear reactors (FSC Class 4470 only). 51 Hand tools. 54 Prefabricated structure and scaffolding (FSC Class...

  9. High-Throughput Processes and Structural Characterization of Single-Nanotube Based Devices for 3D Electronics

    NASA Technical Reports Server (NTRS)

    Kaul, A. B.; Megerian, K. G.; Baron, R. L.; Jennings, A. T.; Jang, D.; Greer, J. R.

    2011-01-01

    We have developed manufacturable approaches to form single, vertically aligned carbon nanotubes, where the tubes are centered precisely, and placed within a few hundred nm of 1-1.5 micron deep trenches. These wafer-scale approaches were enabled by chemically amplified resists and inductively coupled Cryo-etchers to form the 3D nanoscale architectures. The tube growth was performed using dc plasmaenhanced chemical vapor deposition (PECVD), and the materials used for the pre-fabricated 3D architectures were chemically and structurally compatible with the high temperature (700 C) PECVD synthesis of our tubes, in an ammonia and acetylene ambient. The TEM analysis of our tubes revealed graphitic basal planes inclined to the central or fiber axis, with cone angles up to 30 deg. for the particular growth conditions used. In addition, bending tests performed using a custom nanoindentor, suggest that the tubes are well adhered to the Si substrate. Tube characteristics were also engineered to some extent, by adjusting growth parameters, such as Ni catalyst thickness, pressure and plasma power during growth.

  10. High-throughput processes and structural characterization of single-nanotube based devices for 3D electronics

    NASA Astrophysics Data System (ADS)

    Kaul, A. B.; Megerian, K. G.; Baron, R. L.; Jennings, A. T.; Jang, D.; Greer, J. R.

    2009-05-01

    We have developed manufacturable approaches to form single, vertically aligned carbon nanotubes, where the tubes are centered precisely, and placed within a few hundred nm of 1-1.5 μm deep trenches. These wafer-scale approaches were enabled by chemically amplified resists and inductively coupled Cryo-etchers to form the 3D nanoscale architectures. The tube growth was performed using dc plasmaenhanced chemical vapor deposition (PECVD), and the materials used for the pre-fabricated 3D architectures were chemically and structurally compatible with the high temperature (700 °C) PECVD synthesis of our tubes, in an ammonia and acetylene ambient. The TEM analysis of our tubes revealed graphitic basal planes inclined to the central or fiber axis, with cone angles up to 30° for the particular growth conditions used. In addition, bending tests performed using a custom nanoindentor, suggest that the tubes are well adhered to the Si substrate. Tube characteristics were also engineered to some extent, by adjusting growth parameters, such as Ni catalyst thickness, pressure and plasma power during growth.

  11. Cell Structure

    MedlinePlus

    ... Cells, Tissues, & Membranes Cell Structure & Function Cell Structure Cell Function Body Tissues Epithelial Tissue Connective Tissue Muscle Tissue ... apparatus , and lysosomes . « Previous (Cell Structure & Function) Next (Cell Function) » Contact Us | Privacy Policy | Accessibility | FOIA | File Formats ...

  12. Photoelastic stress analysis of different prefabricated post-and-core materials.

    PubMed

    Asvanund, Pattapon; Morgano, Steven M

    2011-01-01

    The purpose of this study was to investigate stress developed by a combination of a stainless steel post or a fiber-reinforced resin post with a silver amalgam core or a composite resin core. Two-dimensional photoelastic models were used to simulate root dentin. Posts (ParaPost XT and ParaPost-FiberWhite) were cemented with a luting agent (RelyX Unicem). Silver amalgam cores and composite resin cores were fabricated on the posts. Complete crowns were fabricated and cemented on the cores. Each model was analyzed with 2 force magnitudes and in 2 directions. Fringe orders were recorded and compared using ANOVA (p=0.05) and the Scheffe's test. With vertical force, no stress differences occurred among the 4 groups (p=0.159). With a 30-degree force, there was stress differences among the 4 groups (p<0.001). The combination of a fiber-reinforced post and composite resin core could potentially reduce stresses within the radicular dentin when angled loads are applied. PMID:21946489

  13. Repair of calvarial defects in rats by prefabricated, degradable, long fibre composite implants.

    PubMed

    Scotchford, C A; Shahtaheri, M; Shataheri, M; Chen, P-S; Evans, M; Parsons, A J; Aitchison, G A; Efeoglu, C; Burke, J L; Vikram, A; Fisher, S E; Rudd, C D

    2011-01-01

    We report results from an initial small animal study designed to provide information on the biocompatibility of a novel biodegradable composite designed for craniomaxillofacial reconstruction. Rat calvarium was chosen as a clinically analogous model, which allowed comparison between experimental groups (PCL alone, PCL/phosphate glass, or PCL/bioglass implants) and control groups (empty defects or bone grafted defects). All animals recovered well from surgery and no clinical complications were observed. Histological assessment indicated a lack of inflammatory response. The amount of new bone formation at the dural aspect of the implant was statistically significantly higher in the PCL/phosphate glass group than the other experimental groups. This study confirms, in a clinically analogous model, the promise of the novel PCL/phosphate glass composite material. Work is planned toward manufacturing scale up and clinical trials. PMID:21105172

  14. Custom prefabrication of silicone tubes from urinary catheters for experimental peripheral nerve surgery.

    PubMed

    Saray, Aydin

    2004-01-01

    The entubulation principle represents a neurobiological approach to nerve surgery in which the role of the surgeon is limited and intrinsic healing capabilities of the nerve play the primary role. Herein, a technique for fabricating custom-made silicone tubes from a silicone urinary catheter is described. Silicone tubes with varying size and dimensions can be tailored depending on the diameter of the silicone urinary catheter (14 F to 18 F). Tubes crafted from silicone urinary catheters were used either as a nerve conduit to facilitate regeneration or as compressive nerve banding to simulate compressive neuropathy in the rat sciatic nerve. Custom-made silicone tubes have similar pros and cons to the commercially available silicone tubes regarding the capsule and foreign body reaction. It can be concluded that these cost effective tubes can be easily cut and used in experimental peripheral nerve surgery in developing countries where the cost of such materials becomes an important issue for the researchers. PMID:24115867

  15. Ex Vivo Prefabricated Rat Skin Flap Using Cell Sheets and an Arteriovenous Vascular Bundle

    PubMed Central

    Fujisawa, Daisuke; Sekine, Hidekazu; Okano, Teruo; Sakurai, Hiroyuki

    2015-01-01

    Background: Recently, research on tissue-engineered skin substitutes have been active in plastic surgery, and significant development has been made in this area over the past several decades. However, a regenerative skin flap has not been developed that could provide immediate blood flow after transplantation. Here, we make a regenerative skin flap ex vivo that is potentially suitable for microsurgical transplantation in future clinical applications. Methods: In rats, for preparing a stable vascular carrier, a femoral vascular pedicle was sandwiched between collagen sponges and inserted into a porous chamber in the abdomen. The vascular bed was harvested 3 weeks later, and extracorporeal perfusion was performed. A green fluorescent protein positive epidermal cell sheet was placed on the vascular bed. After perfusion culture, the whole construct was harvested and fixed for morphological analyses. Results: After approximately 10 days perfusion, the epidermal cell sheet cornified sufficiently. The desquamated corneum was positive for filaggrin. The basement membrane protein laminin 332 and type 4 collagen were deposited on the interface area between the vascular bed and the epidermal cell sheet. Moreover, an electron microscopic image showed anchoring junctions and keratohyalin granules. These results show that we were able to produce native-like skin. Conclusions: We have succeeded in creating regenerative skin flap ex vivo that is similar to native skin, and this technique could be applied to create various tissues in the future. PMID:26180725

  16. Removable Partial Denture Supported by Implants with Prefabricated Telescopic Abutments - A Case Report

    PubMed Central

    Sehgal, Komal

    2014-01-01

    Implants have been designed to rehabilitate edentulous patients with fixed prosthesis or implant supported overdentures. Implant-supported single crowns and fixed partial dentures have become successful treatment alternatives to removable and fixed partial dentures. However, it is common to have clinical situations which make it impossible to use conventional as well as implant supported fixed partial dentures. The implant supported removable partial dentures can be a treatment modality that offers the multitude of benefits of implant-based therapy—biologic, biomechanical, social, and psychological to such patients. The aim of this article is to present a case report describing the fabrication and advantages of removable partial denture supported by teeth and implants for a patient with long edentulous span. The patient was satisfied with his dentures in terms of function and aesthetics. Regular follow-up visits over a period of three years revealed that the periodontal condition of remaining natural dentition and peri-implant conditions were stable. There was no evidence of excessive residual ridge resorption or mobility of the teeth, nor were any visible changes in the bone levels of the natural teeth or implants noted on radiographs. PMID:25121066

  17. Zirconia-Prefabricated Crowns for Pediatric Patients With Primary Dentition: Technique and Cementation for Esthetic Outcomes.

    PubMed

    Cohn, Carla

    2016-09-01

    Traditionally, many clinicians tend to forego esthetic considerations when full-coverage restorations are indicated for pediatric patients with primary dentitions. However, the availability of new zirconia pediatric crowns and reliable techniques for cementation makes esthetic outcomes practical and consistent when restoring primary dentition. Two cases are described: a 3-year-old boy who presented with severe early childhood caries affecting both anterior and posterior teeth, and a 6-year-old boy who presented with extensive caries of his primary posterior dentition, including a molar requiring full coverage. The parents of both boys were concerned about esthetics, and the extent of decay indicated the need for full-coverage restorations. This led to the boys receiving treatment using a restorative procedure in which the carious teeth were prepared for and restored with esthetic tooth-colored zirconia crowns. In both cases, comfortable function and pleasing esthetics were achieved. PMID:27608199

  18. Silicon sample holder for molecular beam epitaxy on pre-fabricated integrated circuits

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael E. (Inventor); Grunthaner, Paula J. (Inventor); Grunthaner, Frank J. (Inventor)

    1994-01-01

    The sample holder of the invention is formed of the same semiconductor crystal as the integrated circuit on which the molecular beam expitaxial process is to be performed. In the preferred embodiment, the sample holder comprises three stacked micro-machined silicon wafers: a silicon base wafer having a square micro-machined center opening corresponding in size and shape to the active area of a CCD imager chip, a silicon center wafer micro-machined as an annulus having radially inwardly pointing fingers whose ends abut the edges of and center the CCD imager chip within the annulus, and a silicon top wafer micro-machined as an annulus having cantilevered membranes which extend over the top of the CCD imager chip. The micro-machined silicon wafers are stacked in the order given above with the CCD imager chip centered in the center wafer and sandwiched between the base and top wafers. The thickness of the center wafer is about 20% less than the thickness of the CCD imager chip. Preferably, four titanium wires, each grasping the edges of the top and base wafers, compress all three wafers together, flexing the cantilever fingers of the top wafer to accommodate the thickness of the CCD imager chip, acting as a spring holding the CCD imager chip in place.

  19. Concepts and strategies for lunar base radiation protection - Prefabricated versus in-situ materials

    NASA Technical Reports Server (NTRS)

    Simonsen, Lisa C.; Nealy, John E.; Townsend, Lawrence W.

    1992-01-01

    The most recently accepted environment data are used as inputs for the Langley nucleon and heavy-ion transport codes, BRYNTRN and HZETRN, to examine the shield effectiveness of lunar regolith in comparison with commercially-used shield materials in nuclear facilities. Several of the fabricated materials categorized as neutron absorbers exhibit favorable characteristics for space radiation protection. In particular, polyethylene with additive boron is analyzed with regard to response to the predicted lunar galactic cosmic ray and solar proton flare environment during the course of a complete solar cycle. Although this effort is not intended to be a definitive trade study for specific shielding recommendations, attention is given to several factors that warrant consideration in such trade studies. For example, the transporting of bulk shield material to the lunar site as opposed to regolith-moving and processing equipment is assessed on the basis of recent scenario studies. The transporting of shield material from Earth may also be a viable alternative to the use of regolith from standpoints of cost-effectiveness, EVA time required, and risk factor.

  20. On-site experiment for towing procedure of pre-fabricated tendon of TLP

    SciTech Connect

    Morikawa, Masao; Ishikawa, Kuniteru; Suzuki, Hideyuki; Yoshida, Koichiro

    1994-12-31

    Research and development of the Tension Leg Platform (TLP) have been performed in the Offshore Oil and Gas Production Platform Project of Japan Ocean Industries Association (JOIA) promoted by the Ministry of International Trade and Industry, Japan (MITI). In this project, the tendons that are planned to be fabricated and assembled on the land in an overall length will be horizontally toward to the site. After that, they will be installed there. The towing procedure, however, has been established neither theoretically nor empirically. Therefore, the on-site experiment was performed to investigate whether it is possible to plan the towing procedure at the sea. The bending moment and the towing force of the tendon model during the towing procedure were measured.

  1. Information Structure and Linguistic Structure.

    ERIC Educational Resources Information Center

    Zierer, Ernesto

    1972-01-01

    This document describes a format for analyzing the information content of sentences and the language patterns that accompany particular information content. The author writes in terms of information structures, each information structure having a corresponding linguistic structure composed of distinctive features. The information structure of a…

  2. Classifying structures

    SciTech Connect

    Buslov, V.M.; Krahl, N.W.

    1985-01-01

    61 concepts are categorized and divided by structure type into bottom-mounted, floating, and island structures. They are either permanent systems or moving systems. They are further subdivided and listed in this paper. The structural designs are all distinguished by the consideration of sea ice. Bottom-mounted structures have been built in water depths from 30 to about 500 feet. To date, only a few steel or concrete structures have been built, but a number are being planned. A list of concrete structures now in operation is provided.

  3. A Dome Amidst the Hexagons

    ERIC Educational Resources Information Center

    American School and University, 1976

    1976-01-01

    Describes the design of the gymnasium of York (South Carolina) Comprehensive High School, a circular 12,000 square foot structure with a prefabricated domed roof constructed of steel hubs and curved wooden beams. (JG)

  4. Website Structure

    ERIC Educational Resources Information Center

    Jackson, Larry S.

    2009-01-01

    This dissertation reports the results of an exploratory data analysis investigation of the relationship between the structures used for information organization and access and the associated storage structures within state government websites. Extending an earlier claim that hierarchical directory structures are both the preeminent information…

  5. Coilgun structures

    NASA Astrophysics Data System (ADS)

    Andrews, J. A.

    1993-01-01

    Recent research into the optimal design of 'coilgun' structures has indicated that structural requirements are strong functions of launcher classification as well as acceleration mode. Attention is presently given to both closed-form and numerical analytical techniques for coaxial DC accelerator (DCA) structural-design calculations. The DCA is a multistage pulsed-induction launcher that makes extensive use of composite materials technology; measured plastic deformations of the armature after a high energy experiment are compared to FEM analysis predictions.

  6. Aeropropulsion structures

    NASA Technical Reports Server (NTRS)

    Nichols, Lester D.

    1987-01-01

    The structural engineer is faced with unique problems when dealing with aeropropulsion systems. He is faced with extremes in operating temperatures, rotational effects, and behaviors of advanced material systems which combine into complexities that require advances in many scientific disciplines involved in structural analysis and design procedures. This presentation provides an overview of the complexities of aeropropulsion structures and the theoretical, computational, and experimental research conducted to achieve the needed advances.

  7. Structural crashworthiness

    SciTech Connect

    Jones, N.; Wierzbicki, T.

    1983-01-01

    Behind the quest for safety in all forms of transport lies a complex technology of which structural crashworthiness forms an important part. This volume contains the work of over twenty experts whose interests range from the fundamental principles of structural collapse to the application of those principles to the design of ships, aircraft, road vehicles, and rail vehicles. The text focuses on the application of analytical and experimental techniques to predict energy dissipation characteristics of thin-walled structures and structural members under quasi-static and dynamic loadings.

  8. Reconfigurable structure

    NASA Technical Reports Server (NTRS)

    Curtis, Steven A. (Inventor)

    2010-01-01

    A reconfigurable structure includes a plurality of selectively extensible and retractable limbs, at least one node pivotably receiving respective ends of at least two limbs, and an actuator associated with each limb for extending and retracting the limb. The structure may further include an addressable module associated with each actuator to control the actuator.

  9. Structural Ceramics

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This publication is a compilation of abstracts and slides of papers presented at the NASA Lewis Structural Ceramics Workshop. Collectively, these papers depict the scope of NASA Lewis' structural ceramics program. The technical areas include monolithic SiC and Si3N4 development, ceramic matrix composites, tribology, design methodology, nondestructive evaluation (NDE), fracture mechanics, and corrosion.

  10. Protein Structure

    ERIC Educational Resources Information Center

    Asmus, Elaine Garbarino

    2007-01-01

    Individual students model specific amino acids and then, through dehydration synthesis, a class of students models a protein. The students clearly learn amino acid structure, primary, secondary, tertiary, and quaternary structure in proteins and the nature of the bonds maintaining a protein's shape. This activity is fun, concrete, inexpensive and…

  11. Organisational Structure

    ERIC Educational Resources Information Center

    National Centre for Vocational Education Research (NCVER), 2006

    2006-01-01

    An understanding of organisational structure can provide guidance for organisations that want to change and innovate. Many writers agree that this understanding allows organisations to shape how their work is done to ultimately achieve their business goals--and that too often structure is given little consideration in business strategy and…

  12. Structured light in structured media

    NASA Astrophysics Data System (ADS)

    Zeng, Jinwei

    The objective of this dissertation is to investigate fundamental optical phenomena at the interface between two emerging fields of modern optics - structured light and micro/nano-structured optical materials. Until recently, these fields were developing in parallel yet independently. A majority of researchers in the field of metamaterials and photonic crystals considered "simple" linearly or circularly polarized light or Gaussian beam propagation in "structured" materials with properties not found in nature. However, in addition to conventional polarization states, light beams can be radially or azimuthally polarized and carry orbital angular momentum (OAM). A fascinating example of a beam carrying OAM is the optical vortex---a donut-shaped beam with a helical phase front. Similarly, the structured light community largely focused on complex light propagation in rather simple homogeneous, isotropic, transparent media. In this dissertation, we explore fundamentals and applications of light-matter interactions that involve both complex light and complex media. The central question that we aim to tackle is: How may the synergy of these two fields lead to a breakthrough in modern photonics? Structured materials, including metamaterials and photonic bandgap structures, realize unprecedented control over light propagation and design flexibility. They can enable new optical properties and functionalities, including new regimes of wave guiding, negative index of refraction, magnetism at optical frequencies, and subwavelength imaging to name a few. We demonstrate how nearly unlimited possibilities in engineering the properties of structured media can be used for generation and manipulation of structured light. Also, we show how the unique properties of structured light could be used for characterization of structured media.

  13. Spacecraft Structures

    NASA Video Gallery

    This activity challenges students to solve a real-world problem that is part of the space program using creativity, cleverness and scientific knowledge while learning about forces, structures and e...

  14. Structural Analysis

    NASA Technical Reports Server (NTRS)

    1991-01-01

    After an 800-foot-tall offshore oil recovery platform collapsed, the engineers at Engineering Dynamics, Inc., Kenner, LA, needed to learn the cause of the collapse, and analyze the proposed repairs. They used STAGSC-1, a NASA structural analysis program with geometric and nonlinear buckling analysis. The program allowed engineers to determine the deflected and buckling shapes of the structural elements. They could then view the proposed repairs under the pressure that caused the original collapse.

  15. Structural biology.

    PubMed Central

    Holmes, K C

    1999-01-01

    Protein crystallography has become a major technique for understanding cellular processes. This has come about through great advances in the technology of data collection and interpretation, particularly the use of synchrotron radiation. The ability to express eukaryotic genes in Escherichia coli is also important. Analysis of known structures shows that all proteins are built from about 1000 primeval folds. The collection of all primeval folds provides a basis for predicting structure from sequence. At present about 450 are known. Of the presently sequenced genomes only a fraction can be related to known proteins on the basis of sequence alone. Attempts are being made to determine all (or as many as possible) of the structures from some bacterial genomes in the expectation that structure will point to function more reliably than does sequence. Membrane proteins present a special problem. The next 20 years may see the experimental determination of another 40,000 protein structures. This will make considerable demands on synchrotron sources and will require many more biochemists than are currently available. The availability of massive structure databases will alter the way biochemistry is done. PMID:10670018

  16. Structures research

    NASA Technical Reports Server (NTRS)

    Abu-Saba, Elias; Mcginley, Williams; Shen, Ji-Yao

    1992-01-01

    The main objective of the structures group is to provide quality aerospace research with the Center for Aerospace Research - A NASA Center for Excellence at North Carolina Agricultural and Technical State University. The group includes dedicated faculty and students who have a proven record in the area of structures, in particular space structures. The participating faculty developed accurate mathematical models and effective computational algorithms to characterize the flexibility parameters of joint dominated beam-truss structures. Both experimental and theoretical modelling has been applied to the dynamic mode shapes and mode frequencies for a large truss system. During the past few months, the above procedures has been applied to the hypersonic transport plane model. The plane structure has been modeled as a lumped mass system by Doctor Abu-Saba while Doctor Shen applied the transfer matrix method with a piecewise continuous Timoshenko tapered beam model. Results from both procedures compare favorably with those obtained using the finite element method. These two methods are more compact and require less computer time than the finite element method. The group intends to perform experiments on structural systems including the hypersonic plane model to verify the results from the theoretical models.

  17. Structures Division

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The NASA Lewis Research Center Structures Division is an international leader and pioneer in developing new structural analysis, life prediction, and failure analysis related to rotating machinery and more specifically to hot section components in air-breathing aircraft engines and spacecraft propulsion systems. The research consists of both deterministic and probabilistic methodology. Studies include, but are not limited to, high-cycle and low-cycle fatigue as well as material creep. Studies of structural failure are at both the micro- and macrolevels. Nondestructive evaluation methods related to structural reliability are developed, applied, and evaluated. Materials from which structural components are made, studied, and tested are monolithics and metal-matrix, polymer-matrix, and ceramic-matrix composites. Aeroelastic models are developed and used to determine the cyclic loading and life of fan and turbine blades. Life models are developed and tested for bearings, seals, and other mechanical components, such as magnetic suspensions. Results of these studies are published in NASA technical papers and reference publication as well as in technical society journal articles. The results of the work of the Structures Division and the bibliography of its publications for calendar year 1995 are presented.

  18. Composite structural materials. [aircraft structures

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1980-01-01

    The use of filamentary composite materials in the design and construction of primary aircraft structures is considered with emphasis on efforts to develop advanced technology in the areas of physical properties, structural concepts and analysis, manufacturing, and reliability and life prediction. The redesign of a main spar/rib region on the Boeing 727 elevator near its actuator attachment point is discussed. A composite fabrication and test facility is described as well as the use of minicomputers for computer aided design. Other topics covered include (1) advanced structural analysis methids for composites; (2) ultrasonic nondestructive testing of composite structures; (3) optimum combination of hardeners in the cure of epoxy; (4) fatigue in composite materials; (5) resin matrix characterization and properties; (6) postbuckling analysis of curved laminate composite panels; and (7) acoustic emission testing of composite tensile specimens.

  19. Tension Structure

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The fabric structure pictured is the Campus Center of La Verne College, La Verne, California. Unlike the facilities shown on the preceding pages, it is not air-supported. It is a "tension structure," its multi-coned fabric membrane supported by a network of cables attached to steel columns which function like circus tent poles. The spider-web in the accompanying photo is a computer graph of the tension pattern. The designers, Geiger-Berger Associates PC, of New York City, conducted lengthy computer analysis to determine the the best placement of columns and cables. The firm also served as structural engineering consultant on the Pontiac Silverdome and a number of other large fabric structures. Built by Birdair Structures, Inc., Buffalo, New York, the La Verne Campus Center was the first permanent facility in the United States enclosed by the space-spinoff fabric made of Owens-Corning Beta fiber glass coated with Du Pont Teflon TFE. The flexible design permits rearrangement of the interior to accommodate athletic events, student activities, theatrical productions and other recreational programs. Use of fabric covering reduced building cost 30 percent below conventional construction.

  20. Lightweight Structures.

    ERIC Educational Resources Information Center

    Shaver and Co., Michigan City, IN.

    One of the newest and most promising developments in architecture has been the use of lightweight structures for encapsulating space. Using this new technology, builders can enclose large and small areas at a fraction of the cost of conventional construction and at the same time provide interior space that is totally flexible. This brochure shows…

  1. Structural evolution

    SciTech Connect

    Burr, M.T.

    1993-03-01

    In this special report, financial executives discuss key trends in power project finance, new funding sources and evolving project structures. Industry wide, financial firms and developers are striving to improve the cost-effectiveness and efficiency of project financing, for projects in both greenfield development and the growing secondary market.

  2. Nanocrystal structures

    SciTech Connect

    Eisler, Hans J.; Sundar, Vikram C.; Walsh, Michael E.; Klimov, Victor I.; Bawendi, Moungi G.; Smith, Henry I.

    2008-12-30

    A structure including a grating and a semiconductor nanocrystal layer on the grating, can be a laser. The semiconductor nanocrystal layer can include a plurality of semiconductor nanocrystals including a Group II-VI compound, the nanocrystals being distributed in a metal oxide matrix. The grating can have a periodicity from 200 nm to 500 nm.

  3. Nanocrystal structures

    DOEpatents

    Eisler, Hans J.; Sundar, Vikram C.; Walsh, Michael E.; Klimov, Victor I.; Bawendi, Moungi G.; Smith, Henry I.

    2006-12-19

    A structure including a grating and a semiconductor nanocrystal layer on the grating, can be a laser. The semiconductor nanocrystal layer can include a plurality of semiconductor nanocrystals including a Group II–VI compound, the nanocrystals being distributed in a metal oxide matrix. The grating can have a periodicity from 200 nm to 500 nm.

  4. Lightweight Structures

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel

    2001-01-01

    Present structural concepts for hot static structures are conventional "sheet & stringer" or truss core construction. More weight-efficient concepts such as honeycomb and lattice block are being investigated, in combination with both conventional superalloys and TiAl. Development efforts for components made from TiAl sheet are centered on lower cost methods for sheet and foil production, plus alloy development for higher temperature capability. A low-cost casting technology recently developed for aluminum and steel lattice blocks has demonstrated the required higher strength and stiffness, with weight efficiency approach- ing honeycombs. The current effort is based on extending the temperature capability by developing lattice block materials made from IN-718 and Mar-M247.

  5. Structural Geology

    NASA Astrophysics Data System (ADS)

    Weber, John; Frankel, Kurt L.

    2011-05-01

    Structural geology and continental tectonics were ushered in to the modern quantitative age of geosciences with the arrival of the global plate tectonics paradigm (circa 1968), derived using new data from the oceans' depths, and John Ramsay's 1967 seminal work, Folding and Fracturing of Rocks. Fossen is to be applauded for crafting a unique, high-caliber, and accessible undergraduate textbook on structural geology that faithfully reflects this advance and the subsequent evolution of the discipline. This well-written text draws on Fossen's wealth of professional experience, including his broad and diverse academic research and experience in the petroleum industry. This book is beautifully illustrated, with excellent original color diagrams and with impressive color field photographs that are all keyed to locations and placed into geologic context.

  6. Superconducting Structure

    DOEpatents

    Kwon, Chuhee; Jia, Quanxi; Foltyn, Stephen R.

    2005-09-13

    A superconductive structure including a dielectric oxide substrate, a thin buffer layer of a superconducting material thereon; and, a layer of a rare earth-barium-copper oxide superconducting film thereon the thin layer of yttrium-barium-copper oxide, the rare earth selected from the group consisting of samarium, gadolinium, ytterbium, erbium, neodymium, dysprosium, holmium, lutetium, a combination of more than one element from the rare earth group and a combination of one or more elements from the rare earth group with yttrium, the buffer layer of superconducting material characterized as having chemical and structural compatibility with the dielectric oxide substrate and the rare earth-barium-copper oxide superconducting film is provided.

  7. Superconducting structure

    DOEpatents

    Kwon, Chuhee; Jia, Quanxi; Foltyn, Stephen R.

    2003-04-01

    A superconductive structure including a dielectric oxide substrate, a thin buffer layer of a superconducting material thereon; and, a layer of a rare earth-barium-copper oxide superconducting film thereon the thin layer of yttrium-barium-copper oxide, the rare earth selected from the group consisting of samarium, gadolinium, ytterbium, erbium, neodymium, dysprosium, holmium, lutetium, a combination of more than one element from the rare earth group and a combination of one or more elements from the rare earth group with yttrium, the buffer layer of superconducting material characterized as having chemical and structural compatibility with the dielectric oxide substrate and the rare earth-barium-copper oxide superconducting film is provided.

  8. Terminal structure

    DOEpatents

    Schmidt, Frank; Allais, Arnaud; Mirebeau, Pierre; Ganhungu, Francois; Lallouet, Nicolas

    2009-10-20

    A terminal structure (2) for a superconducting cable (1) is described. It consists of a conductor (2a) and an insulator (2b) that surrounds the conductor (2a), wherein the superconducting cable (1) has a core with a superconducting conductor (5) and a layer of insulation that surrounds the conductor (5), and wherein the core is arranged in such a way that it can move longitudinally in a cryostat. The conductor (2a) of the terminal structure (2) is electrically connected with the superconducting conductor (5) or with a normal conductor (6) that is connected with the superconducting conductor (5) by means of a tubular part (7) made of an electrically conductive material, wherein the superconducting conductor (5) or the normal conductor (6) can slide in the part (7) in the direction of the superconductor.

  9. Fabrication, Characterization, And Deformation of 3D Structural Meta-Materials

    NASA Astrophysics Data System (ADS)

    Montemayor, Lauren C.

    Current technological advances in fabrication methods have provided pathways to creating architected structural meta-materials similar to those found in natural organisms that are structurally robust and lightweight, such as diatoms. Structural meta-materials are materials with mechanical properties that are determined by material properties at various length scales, which range from the material microstructure (nm) to the macro-scale architecture (mum -- mm). It is now possible to exploit material size effect, which emerge at the nanometer length scale, as well as structural effects to tune the material properties and failure mechanisms of small-scale cellular solids, such as nanolattices. This work demonstrates the fabrication and mechanical properties of 3-dimensional hollow nanolattices in both tension and compression. Hollow gold nanolattices loaded in uniaxial compression demonstrate that strength and stiffness vary as a function of geometry and tube wall thickness. Structural effects were explored by increasing the unit cell angle from 30° to 60° while keeping all other parameters constant; material size effects were probed by varying the tube wall thickness, t, from 200nm to 635nm, at a constant relative density and grain size. In-situ uniaxial compression experiments reveal an order-of-magnitude increase in yield stress and modulus in nanolattices with greater lattice angles, and a 150% increase in the yield strength without a concomitant change in modulus in thicker-walled nanolattices for fixed lattice angles. These results imply that independent control of structural and material size effects enables tunability of mechanical properties of 3-dimensional architected meta-materials and highlight the importance of material, geometric, and microstructural effects in small-scale mechanics. This work also explores the flaw tolerance of 3D hollow-tube alumina kagome nanolattices with and without pre-fabricated notches, both in experiment and simulation

  10. Airfoil structure

    DOEpatents

    Frey, G.A.; Twardochleb, C.Z.

    1998-01-13

    Past airfoil configurations have been used to improve aerodynamic performance and engine efficiencies. The present airfoil configuration further increases component life and reduces maintenance by reducing internal stress within the airfoil itself. The airfoil includes a chord and a span. Each of the chord and the span has a bow being summed to form a generally ``C`` configuration of the airfoil. The generally ``C`` configuration includes a compound bow in which internal stresses resulting from a thermal temperature gradient are reduced. The structural configuration reduces internal stresses resulting from thermal expansion. 6 figs.

  11. Airfoil structure

    DOEpatents

    Frey, Gary A.; Twardochleb, Christopher Z.

    1998-01-01

    Past airfoil configurations have been used to improve aerodynamic performance and engine efficiencies. The present airfoil configuration further increases component life and reduces maintenance by reducing internal stress within the airfoil itself. The airfoil includes a chord and a span. Each of the chord and the span has a bow being summed to form a generally "C" configuration of the airfoil. The generally "C" configuration includes a compound bow in which internal stresses resulting from a thermal temperature gradient are reduced. The structural configuration reduces internal stresses resulting from thermal expansion.

  12. Digital structural

    USGS Publications Warehouse

    Dohm, J.M.; Anderson, R.C.; Tanaka, K.L.

    1998-01-01

    Magmatic and tectonic activity have both contributed significantly to the surface geology of Mars. Digital structural mapping techniques have now been used to classify and date centers of tectonic activity in the western equatorial region. For example, our results show a center of tectonic activity at Valles Marineris, which may be associated with uplift caused by intrusion. Such evidence may help explain, in part, the development of the large troughs and associated outflow channels and chaotic terrain. We also find a local centre of tectonic activity near the source region of Warrego Valles. Here, we suggest that the valley system may have resulted largely from intrusive-related hydrothermal activity. We hope that this work, together with the current Mars Global Surveyor mission, will lead to a better understanding of the geological processes that shaped the Martian surface.

  13. Armor structures

    DOEpatents

    Chu, Henry Shiu-Hung [Idaho Falls, ID; Lacy, Jeffrey M [Idaho Falls, ID

    2008-04-01

    An armor structure includes first and second layers individually containing a plurality of i-beams. Individual i-beams have a pair of longitudinal flanges interconnected by a longitudinal crosspiece and defining opposing longitudinal channels between the pair of flanges. The i-beams within individual of the first and second layers run parallel. The laterally outermost faces of the flanges of adjacent i-beams face one another. One of the longitudinal channels in each of the first and second layers faces one of the longitudinal channels in the other of the first and second layers. The channels of the first layer run parallel with the channels of the second layer. The flanges of the first and second layers overlap with the crosspieces of the other of the first and second layers, and portions of said flanges are received within the facing channels of the i-beams of the other of the first and second layers.

  14. Linear-motion tattoo machine and prefabricated needle sets for the delivery of plant viruses by vascular puncture inoculation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vascular puncture inoculation (VPI) of plant viruses previously has been conducted either manually or by use of a commercial engraving tool and laboratory-fabricated needle arrays. In an effort to improve this technique, a linear-motion tattoo machine driving industry-standard needle arrays was tes...

  15. Asteroid structure

    NASA Astrophysics Data System (ADS)

    Asphaug, E.

    2014-07-01

    Even before the first space missions to asteroids, in the mid-1990s, it was known that asteroids have weird structures. Photometry indicated complicated shapes, and the pioneering radar investigations by Ostro and colleagues followed by adaptive optics campaigns and flybys showed odd binary forms, and confirmed the common presence of satellites, and indications of highly varying surface roughness. Some asteroids turned out to be dominated by a single major cratering event, while others showed no evidence of a major crater, or perhaps for global crater erasure. The first space mission to orbit an asteroid, NEAR, found a mixture of heavily cratered terrains and geomorphically active 'ponds', and indicated evidence for global seismicity from impact. The next mission to orbit an asteroid, Hayabusa, found what most agree is a rubble pile, with no major craters and an absence of fines. There is to date no direct evidence of asteroid interior geology, other than measurements of bulk density, and inferences made for mass distribution asymmetry based on dynamics, and inferences based on surface lineaments. Interpolating from the surface to the interior is always risky and usually wrong, but of course the answer is important since we are someday destined to require this knowledge in order to divert a hazardous asteroid from impact with the Earth. Even considering the near-subsurface, here we remain as ignorant as we were about the Moon in the early 1960s, whether the surface will swallow us up in dust, or will provide secure landing and anchoring points. Laboratory experimentation in close to zero-G is still in its early stages. Adventures such as mining and colonization will surely have to wait until we better know these things. How do we get from here to there? I will focus on 3 areas of progress: (1) asteroid cratering seismology, where we use the surface craters to understand what is going on inside; (2) numerical modeling of collisions, which predicts the internal

  16. Computational structural mechanics for engine structures

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    1989-01-01

    The computational structural mechanics (CSM) program at Lewis encompasses the formulation and solution of structural mechanics problems and the development of integrated software systems to computationally simulate the performance, durability, and life of engine structures. It is structured to supplement, complement, and, whenever possible, replace costly experimental efforts. Specific objectives are to investigate unique advantages of parallel and multiprocessing for reformulating and solving structural mechanics and formulating and solving multidisciplinary mechanics and to develop integrated structural system computational simulators for predicting structural performance, evaluating newly developed methods, and identifying and prioritizing improved or missing methods.

  17. Computational structural mechanics for engine structures

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    1988-01-01

    The computational structural mechanics (CSM) program at Lewis encompasses the formulation and solution of structural mechanics problems and the development of integrated software systems to computationally simulate the performance, durability, and life of engine structures. It is structured to supplement, complement, and, whenever possible, replace costly experimental efforts. Specific objectives are to investigate unique advantages of parallel and multiprocessing for reformulating and solving structural mechanics and formulating and solving multidisciplinary mechanics and to develop integrated structural system computational simulators for predicting structural performance, evaluating newly developed methods, and identifying and prioritizing improved or missing methods.

  18. Adaptive Space Structures

    NASA Technical Reports Server (NTRS)

    Wada, B.

    1993-01-01

    The term adaptive structures refers to a structural control approach in which sensors, actuators, electronics, materials, structures, structural concepts, and system-performance-validation strategies are integrated to achieve specific objectives.

  19. Structural Biology Fact Sheet

    MedlinePlus

    ... Home > Science Education > Structural Biology Fact Sheet Structural Biology Fact Sheet Tagline (Optional) Middle/Main Content Area What is structural biology? Structural biology is a field of science focused ...

  20. Structured Data in Structural Analysis Software

    NASA Technical Reports Server (NTRS)

    Kunz, Donald L.; Hopkins, Stewart

    1987-01-01

    This paper discusses the use of computer data structures in finite-element structural analysis programs. A number of data structure types that have been shown to be useful in such programs are introduced and described. A simple finite-element model is used to demonstrate how the given set of data structure types naturally lend themselves to developing software for the model. Different methods of implementing data structures in the context of a program are discussed.

  1. Magnetic multilayer structure

    DOEpatents

    Herget, Philipp; O'Sullivan, Eugene J.; Romankiw, Lubomyr T.; Wang, Naigang; Webb, Bucknell C.

    2016-07-05

    A mechanism is provided for an integrated laminated magnetic device. A substrate and a multilayer stack structure form the device. The multilayer stack structure includes alternating magnetic layers and diode structures formed on the substrate. Each magnetic layer in the multilayer stack structure is separated from another magnetic layer in the multilayer stack structure by a diode structure.

  2. Collapsible Geostrut Structure

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A.

    1994-01-01

    Portable truss structure collapsible into smaller volume for storage and transportation. At new site, reerected quickly, without need to reassemble parts. Structure could be tent, dome, tunnel, or platform. Key element in structure joint, called "geostrut joint," includes internal cable. Structure is network of struts attached to geostrut joints. Pulling cables taut in all joints makes structure rigid. Releasing cables relaxes structure.

  3. Computational structural mechanics for engine structures

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1989-01-01

    The computational structural mechanics (CSM) program at Lewis encompasses: (1) fundamental aspects for formulating and solving structural mechanics problems, and (2) development of integrated software systems to computationally simulate the performance/durability/life of engine structures. It is structured to mainly supplement, complement, and whenever possible replace, costly experimental efforts which are unavoidable during engineering research and development programs. Specific objectives include: investigate unique advantages of parallel and multiprocesses for: reformulating/solving structural mechanics and formulating/solving multidisciplinary mechanics and develop integrated structural system computational simulators for: predicting structural performances, evaluating newly developed methods, and for identifying and prioritizing improved/missing methods needed. Herein the CSM program is summarized with emphasis on the Engine Structures Computational Simulator (ESCS). Typical results obtained using ESCS are described to illustrate its versatility.

  4. Structural Health Monitoring of Large Structures

    NASA Technical Reports Server (NTRS)

    Kim, Hyoung M.; Bartkowicz, Theodore J.; Smith, Suzanne Weaver; Zimmerman, David C.

    1994-01-01

    This paper describes a damage detection and health monitoring method that was developed for large space structures using on-orbit modal identification. After evaluating several existing model refinement and model reduction/expansion techniques, a new approach was developed to identify the location and extent of structural damage with a limited number of measurements. A general area of structural damage is first identified and, subsequently, a specific damaged structural component is located. This approach takes advantage of two different model refinement methods (optimal-update and design sensitivity) and two different model size matching methods (model reduction and eigenvector expansion). Performance of the proposed damage detection approach was demonstrated with test data from two different laboratory truss structures. This space technology can also be applied to structural inspection of aircraft, offshore platforms, oil tankers, ridges, and buildings. In addition, its applications to model refinement will improve the design of structural systems such as automobiles and electronic packaging.

  5. Nonlinear Structural Analysis

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Nonlinear structural analysis techniques for engine structures and components are addressed. The finite element method and boundary element method are discussed in terms of stress and structural analyses of shells, plates, and laminates.

  6. Intelligent adaptive structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.

    1990-01-01

    'Intelligent Adaptive Structures' (IAS) refers to structural systems whose geometric and intrinsic structural characteristics can be automatically changed to meet mission requirements with changing operational scenarios. An IAS is composed of actuators, sensors, and a control logic; these are integrated in a distributed fashion within the elements of the structure. The IAS concepts thus far developed for space antennas and other precision structures should be applicable to civil, marine, automotive, and aeronautical structural systems.

  7. Protein structure mining using a structural alphabet.

    PubMed

    Tyagi, M; de Brevern, A G; Srinivasan, N; Offmann, B

    2008-05-01

    We present a comprehensive evaluation of a new structure mining method called PB-ALIGN. It is based on the encoding of protein structure as 1D sequence of a combination of 16 short structural motifs or protein blocks (PBs). PBs are short motifs capable of representing most of the local structural features of a protein backbone. Using derived PB substitution matrix and simple dynamic programming algorithm, PB sequences are aligned the same way amino acid sequences to yield structure alignment. PBs are short motifs capable of representing most of the local structural features of a protein backbone. Alignment of these local features as sequence of symbols enables fast detection of structural similarities between two proteins. Ability of the method to characterize and align regions beyond regular secondary structures, for example, N and C caps of helix and loops connecting regular structures, puts it a step ahead of existing methods, which strongly rely on secondary structure elements. PB-ALIGN achieved efficiency of 85% in extracting true fold from a large database of 7259 SCOP domains and was successful in 82% cases to identify true super-family members. On comparison to 13 existing structure comparison/mining methods, PB-ALIGN emerged as the best on general ability test dataset and was at par with methods like YAKUSA and CE on nontrivial test dataset. Furthermore, the proposed method performed well when compared to flexible structure alignment method like FATCAT and outperforms in processing speed (less than 45 s per database scan). This work also establishes a reliable cut-off value for the demarcation of similar folds. It finally shows that global alignment scores of unrelated structures using PBs follow an extreme value distribution. PB-ALIGN is freely available on web server called Protein Block Expert (PBE) at http://bioinformatics.univ-reunion.fr/PBE/. PMID:18004784

  8. Soil Structure Examined

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil structure is the product of the inter-play of all the observed and unobserved forces acting on and within the soil. The most critical component of soil structure for crop productivity is the structure of pore space. Biological organisms play a major role in the development of pore structure a...

  9. Describing Cognitive Structure.

    ERIC Educational Resources Information Center

    White, Richard T.

    This paper discusses questions pertinent to a definition of cognitive structure as the knowledge one possesses and the manner in which it is arranged, and considers how to select or devise methods of describing cognitive structure. The main purpose in describing cognitive structure is to see whether differences in memory (or cognitive structure)…

  10. Materials and structures

    NASA Technical Reports Server (NTRS)

    Venneri, Samuel L.

    1988-01-01

    Information on materials and structures for use in space is given in viewgraph form. Information is given on the Materials and Structures Division of NASA's Office of Aeronautics and Space Technology. The Division's space research and development budget is given. Further information is given on space materials and structures, space environmental effects, radiation effects, high temperature materials research, metal matrix composites, SiC fiber reinforced titanium alloys, structural dynamics, and control of flexible structures.

  11. Teaching Structured Fortran without Structured Extensions.

    ERIC Educational Resources Information Center

    Worland, Peter B.

    Six control structures are used in teaching a college Fortran programing course: (1) simple sequences of instruction without any control statement, (2) IF-THEN selection, (3) IF-THEN-ELSE selection, (4) definite loop, (5) indefinite loop, and (6) generalized IF-THEN-ELSE case structure. Outlines, instead of flowcharts, are employed for algorithm…

  12. 30 CFR 75.1506 - Refuge alternatives.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the unit, shall be approved under 30 CFR part 7; and (2) The structural components of units consisting... CFR part 7. (3) Prefabricated refuge alternative structures that states have approved and those that... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Refuge alternatives. 75.1506 Section...

  13. 30 CFR 75.1506 - Refuge alternatives.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the unit, shall be approved under 30 CFR part 7; and (2) The structural components of units consisting... CFR part 7. (3) Prefabricated refuge alternative structures that states have approved and those that... areas, considering the following factors: proximity to seals; proximity to potential fire or...

  14. 30 CFR 75.1506 - Refuge alternatives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the unit, shall be approved under 30 CFR part 7; and (2) The structural components of units consisting... CFR part 7. (3) Prefabricated refuge alternative structures that states have approved and those that... areas, considering the following factors: proximity to seals; proximity to potential fire or...

  15. 30 CFR 75.1506 - Refuge alternatives.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the unit, shall be approved under 30 CFR part 7; and (2) The structural components of units consisting... CFR part 7. (3) Prefabricated refuge alternative structures that states have approved and those that... areas, considering the following factors: proximity to seals; proximity to potential fire or...

  16. Structural system identification: Structural dynamics model validation

    SciTech Connect

    Red-Horse, J.R.

    1997-04-01

    Structural system identification is concerned with the development of systematic procedures and tools for developing predictive analytical models based on a physical structure`s dynamic response characteristics. It is a multidisciplinary process that involves the ability (1) to define high fidelity physics-based analysis models, (2) to acquire accurate test-derived information for physical specimens using diagnostic experiments, (3) to validate the numerical simulation model by reconciling differences that inevitably exist between the analysis model and the experimental data, and (4) to quantify uncertainties in the final system models and subsequent numerical simulations. The goal of this project was to develop structural system identification techniques and software suitable for both research and production applications in code and model validation.

  17. Structural Engineering: Overview

    NASA Technical Reports Server (NTRS)

    Castro, Edgar

    2011-01-01

    This slide presentation presents the work of the Structural Engineering Division of the Engineering Directorate. The work includes: providing technical expertise and leadership for the development, evaluation, and operation of structural, mechanical, and thermal spaceflight systems.

  18. Space Structure Development

    NASA Technical Reports Server (NTRS)

    Smith, Thomas

    2015-01-01

    The duration of my Summer 2015 Internship Tour at NASA's Johnson Space Center was spent working in the Structural Engineering Division's Structures Branch. One of the two main roles of the Structures Branch, ES2, is to ensure the structural integrity of spacecraft vehicles and the structural subsystems needed to support those vehicles. The other main objective of this branch is to develop the lightweight structures that are necessary to take humans beyond Low-Earth Orbit. Within ES2, my four projects involved inflatable space structure air bladder material testing; thermal and impact material testing for spacecraft windows; structural analysis on a joint used in the Boeing CST-100 airbag system; and an additive manufacturing design project.

  19. Structural materials and components

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor)

    1982-01-01

    High density structural (blocking) materials composed of a polyimide filled with glass microballoons. Structural components such as panels which have integral edgings and/or other parts made of the high density materials.

  20. Structural materials and components

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor)

    1982-01-01

    High density structural (blocking) materials composed of a polyimide filled with glass microballoons and methods for making such materials. Structural components such as panels which have integral edgings and/or other parts made of the high density materials.

  1. Lightweight Materials & Structures

    NASA Video Gallery

    The Lightweight Materials and Structures (LMS) project will mature high-payoff structures and materials technologies that have direct application to NASA’s future space exploration needs.One of the...

  2. Structural materials and components

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor)

    1983-01-01

    High density structural (blocking) materials composed of a polyimide filled with glass microballoons. Structural components such as panels which have integral edgings and/or other parts made of the high density materials.

  3. Structural health monitoring for ship structures

    SciTech Connect

    Farrar, Charles; Park, Gyuhae; Angel, Marian; Bement, Matthew; Salvino, Liming

    2009-01-01

    Currently the Office of Naval Research is supporting the development of structural health monitoring (SHM) technology for U.S. Navy ship structures. This application is particularly challenging because of the physical size of these structures, the widely varying and often extreme operational and environmental conditions associated with these ships missions, lack of data from known damage conditions, limited sensing that was not designed specifically for SHM, and the management of the vast amounts of data that can be collected during a mission. This paper will first define a statistical pattern recognition paradigm for SHM by describing the four steps of (1) Operational Evaluation, (2) Data Acquisition, (3) Feature Extraction, and (4) Statistical Classification of Features as they apply to ship structures. Note that inherent in the last three steps of this process are additional tasks of data cleansing, compression, normalization and fusion. The presentation will discuss ship structure SHM challenges in the context of applying various SHM approaches to sea trials data measured on an aluminum multi-hull high-speed ship, the HSV-2 Swift. To conclude, the paper will discuss several outstanding issues that need to be addressed before SHM can make the transition from a research topic to actual field applications on ship structures and suggest approaches for addressing these issues.

  4. Neutron reflecting supermirror structure

    DOEpatents

    Wood, James L.

    1992-01-01

    An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources.

  5. Neutron reflecting supermirror structure

    DOEpatents

    Wood, J.L.

    1992-12-01

    An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. 2 figs.

  6. Endjoints For Structural Elements

    NASA Technical Reports Server (NTRS)

    Bush, Harold G.; Mikulas, Martin M.; Wallsom, Richard E.

    1989-01-01

    Endjoint and connecting-node system designed for use in erection of frames. System structurally sound and simple to operate. All nodes and struts interchangeable. Nodes and struts attach to form cubic cell structures to produce beams, platforms, towers, or combinations of these. Design suitable for use in construction of space structures and such terrestrial skeletal frameworks as antenna-reflector supports, roof structures for large buildings, lookout towers, radio-transmitter towers, powerline pylons, and scaffolds.

  7. Structural Enhancement of Learning

    ERIC Educational Resources Information Center

    Trumpower, David L.; Goldsmith, Timothy E.

    2004-01-01

    Structural learning aids, such as interactive overviews (IOs), have previously been shown to facilitate text comprehension and recall. In this study, we examined the effects of structural aids on learners' structural knowledge and their performance on a procedural transfer task. In Experiment 1, 90 college students were presented definitions of…

  8. Building safer structures

    USGS Publications Warehouse

    Celebi, Mehmet; Page, Robert A.; Seekins, Linda

    1995-01-01

    In this century, major earthquakes in the United States have damaged or destroyed numerous buildings, bridges, and other structures. By monitoring how structures respond to earthquakes and applying the knowledge gained, scientists and engineers are improving the ability of structures to survive major earthquakes. Many lives and millions of dollars have already been saved by this ongoing research.

  9. The Structures of Life

    ERIC Educational Resources Information Center

    National Institute of General Medical Sciences (NIGMS), 2007

    2007-01-01

    This booklet reveals how structural biology provides insight into health and disease and is useful in developing new medications. It contains a general introduction to proteins, coverage of the techniques used to determine protein structures, and a chapter on structure-based drug design. The booklet features "Student Snapshots," designed to…

  10. HIV Structural Database

    National Institute of Standards and Technology Data Gateway

    SRD 102 HIV Structural Database (Web, free access)   The HIV Protease Structural Database is an archive of experimentally determined 3-D structures of Human Immunodeficiency Virus 1 (HIV-1), Human Immunodeficiency Virus 2 (HIV-2) and Simian Immunodeficiency Virus (SIV) Proteases and their complexes with inhibitors or products of substrate cleavage.

  11. Catalytic distillation structure

    DOEpatents

    Smith, Jr., Lawrence A.

    1984-01-01

    Catalytic distillation structure for use in reaction distillation columns, a providing reaction sites and distillation structure and consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and being present with the catalyst component in an amount such that the catalytic distillation structure consist of at least 10 volume % open space.

  12. Vitrified underground structures

    DOEpatents

    Murphy, Mark T.; Buelt, James L.; Stottlemyre, James A.; Tixier, Jr., John S.

    1992-01-01

    A method of making vitrified underground structures in which 1) the vitrification process is started underground, and 2) a thickness dimension is controlled to produce substantially planar vertical and horizontal vitrified underground structures. Structures may be placed around a contaminated waste site to isolate the site or may be used as aquifer dikes.

  13. Structured FORTRAN Preprocessor

    NASA Technical Reports Server (NTRS)

    Flynn, J. A.; Lawson, C. L.; Van Snyder, W.; Tsitsivas, H. N.

    1985-01-01

    SFTRAN3 supports structured programing in FORTRAN environment. Language intended particularly to support two aspects of structured programing -- nestable single-entry control structures and modularization and top-down organization of code. Code designed and written using these SFTRAN3 facilities have fewer initial errors, easier to understand and less expensive to maintain and modify.

  14. Structural Ceramics Database

    National Institute of Standards and Technology Data Gateway

    SRD 30 NIST Structural Ceramics Database (Web, free access)   The NIST Structural Ceramics Database (WebSCD) provides evaluated materials property data for a wide range of advanced ceramics known variously as structural ceramics, engineering ceramics, and fine ceramics.

  15. Weatherizing a Structure.

    ERIC Educational Resources Information Center

    Metz, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with weatherizing a structure. Its objective is for the student to be able to analyze factors related to specific structures that indicate need for weatherizing activities and to determine steps to correct defects in structures that…

  16. Organizational Knowledge Management Structure

    ERIC Educational Resources Information Center

    Walczak, Steven

    2005-01-01

    Purpose: To propose and evaluate a novel management structure that encourages knowledge sharing across an organization. Design/methodology/approach: The extant literature on the impact of organizational culture and its link to management structure is examined and used to develop a new knowledge sharing management structure. Roadblocks to…

  17. Hypermedia 1990 structured Hypertext tutorial

    NASA Technical Reports Server (NTRS)

    Johnson, J. Scott

    1990-01-01

    Hypermedia 1990 structured Hypertext tutorial is presented in the form of view-graphs. The following subject areas are covered: structured hypertext; analyzing hypertext documents for structure; designing structured hypertext documents; creating structured hypertext applications; structuring service and repair documents; maintaining structured hypertext documents; and structured hypertext conclusion.

  18. Modelling ionospheric density structures

    NASA Technical Reports Server (NTRS)

    Schunk, R. W.; Sojka, J. J.

    1989-01-01

    Large-scale density structures are a common feature in the high-latitude ionsphere. The structures were observed in the dayside cusp, polar cap, and nocturnal auroral region over a range of altitudes, including the E-region, F-region and topside ionosphere. The origins, lifetimes and transport characteristics of large-scale density structures were studied with the aid of a three-dimensional, time-dependent ionospheric model. Blob creation due to particle precipitation, the effect that structured electric fields have on the ionosphere, and the lifetimes and transport characteristics of density structures for different seasonal, solar cycle, and interplanetary magnetic field (IMF) conditions were studied. The main conclusions drawn are: (1) the observed precipitation energy fluxes are sufficient for blob creation if the plasma is exposed to the precipitation for 5 to 10 minutes; (2) structured electric fields produce structured electron densities, ion temperatures, and ion composition; (3) the lifetime of an F-region density structure depends on several factors, including the initial location where it was formed, the magnitude of the perturbation, season, solar cycle and IMF; and (4) depending on the IMF, horizontal plasma convection can cause an initial structure to break up into multiple structures of various sizes, remain as a single distorted structure, or become stretched into elongated segments.

  19. Materials and structures

    NASA Technical Reports Server (NTRS)

    Saito, Theodore T.; Langenbeck, Sharon L.; Al-Jamily, Ghanim; Arnold, Joe; Barbee, Troy; Coulter, Dan; Dolgin, Ben; Fichter, Buck; George, Patricia; Gorenstein, Paul

    1992-01-01

    Materials and structures technology covers a wide range of technical areas. Some of the most pertinent issues for the Astrotech 21 missions include dimensionally stable structural materials, advanced composites, dielectric coatings, optical metallic coatings for low scattered light applications, low scattered light surfaces, deployable and inflatable structures (including optical), support structures in 0-g and 1-g environments, cryogenic optics, optical blacks, contamination hardened surfaces, radiation hardened glasses and crystals, mono-metallic telescopes and instruments, and materials characterization. Some specific examples include low coefficients of thermal expansion (CTE) structures (0.01 ppm/K), lightweight thermally stable mirror materials, thermally stable optical assemblies, high reliability/accuracy (1 micron) deployable structures, and characterization of nanometer level behavior of materials/structures for interferometry concepts. Large filled-aperture concepts will require materials with CTE's of 10(exp 9) at 80 K, anti-contamination coatings, deployable and erectable structures, composite materials with CTE's less than 0.01 ppm/K and thermal hysteresis, 0.001 ppm/K. Gravitational detection systems such as LAGOS will require rigid/deployable structures, dimensionally stable components, lightweight materials with low conductivity, and high stability optics. The Materials and Structures panel addressed these issues and the relevance of the Astrotech 21 mission requirements by dividing materials and structures technology into five categories. These categories, the necessary development, and applicable mission/program development phasing are summarized. For each of these areas, technology assessments were made and development plans were defined.

  20. Computers boost structural technology

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Venneri, Samuel L.

    1989-01-01

    Derived from matrix methods of structural analysis and finite element methods developed over the last three decades, computational structures technology (CST) blends computer science, numerical analysis, and approximation theory into structural analysis and synthesis. Recent significant advances in CST include stochastic-based modeling, strategies for performing large-scale structural calculations on new computing systems, and the integration of CST with other disciplinary modules for multidisciplinary analysis and design. New methodologies have been developed at NASA for integrated fluid-thermal structural analysis and integrated aerodynamic-structure-control design. The need for multiple views of data for different modules also led to the development of a number of sophisticated data-base management systems. For CST to play a role in the future development of structures technology and in the multidisciplinary design of future flight vehicles, major advances and computational tools are needed in a number of key areas.

  1. Inverse structure functions

    SciTech Connect

    Pearson, Bruce R.; Water, Willem van de

    2005-03-01

    While the ordinary structure function in turbulence is concerned with the statistical moments of the velocity increment {delta}u measured over a distance r, the inverse structure function is related to the distance r where the turbulent velocity exits the interval {delta}u. We study inverse structure functions of wind-tunnel turbulence which covers a range of Reynolds numbers Re{sub {lambda}}=400-1100. We test a recently proposed relation between the scaling exponents of the ordinary structure functions and those of the inverse structure functions [S. Roux and M. H. Jensen, Phys. Rev. E 69, 16309 (2004)]. The relatively large range of Reynolds numbers in our experiment also enables us to address the scaling with Reynolds number that is expected to highlight the intermediate dissipative range. While we firmly establish the (relative) scaling of inverse structure functions, our experimental results fail both predictions. Therefore, the question of the significance of inverse structure functions remains open.

  2. Structures of membrane proteins

    PubMed Central

    Vinothkumar, Kutti R.; Henderson, Richard

    2010-01-01

    In reviewing the structures of membrane proteins determined up to the end of 2009, we present in words and pictures the most informative examples from each family. We group the structures together according to their function and architecture to provide an overview of the major principles and variations on the most common themes. The first structures, determined 20 years ago, were those of naturally abundant proteins with limited conformational variability, and each membrane protein structure determined was a major landmark. With the advent of complete genome sequences and efficient expression systems, there has been an explosion in the rate of membrane protein structure determination, with many classes represented. New structures are published every month and more than 150 unique membrane protein structures have been determined. This review analyses the reasons for this success, discusses the challenges that still lie ahead, and presents a concise summary of the key achievements with illustrated examples selected from each class. PMID:20667175

  3. Defining Dynamic Route Structure

    NASA Technical Reports Server (NTRS)

    Zelinski, Shannon; Jastrzebski, Michael

    2011-01-01

    This poster describes a method for defining route structure from flight tracks. Dynamically generated route structures could be useful in guiding dynamic airspace configuration and helping controllers retain situational awareness under dynamically changing traffic conditions. Individual merge and diverge intersections between pairs of flights are identified, clustered, and grouped into nodes of a route structure network. Links are placed between nodes to represent major traffic flows. A parametric analysis determined the algorithm input parameters producing route structures of current day flight plans that are closest to todays airway structure. These parameters are then used to define and analyze the dynamic route structure over the course of a day for current day flight paths. Route structures are also compared between current day flight paths and more user preferred paths such as great circle and weather avoidance routing.

  4. Structural tailoring of select fiber composite structures

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.; Rubinstein, Robert I.

    1990-01-01

    A multidisciplinary design process for aerospace propulsion composite structures was formalized and embedded into computer codes. These computer codes are streamlined to obtain tailored designs for select composite structures. The codes available are briefly described with sample cases to illustrate their applications. The sample cases include aircraft engine blades, propfans (turboprops), flat, and cylindrical panels. Typical results illustrate that the use of these codes enable the designer to obtain designs which meet all the design requirements with maximum benefits in efficiency, noise, weight or thermal distortions.

  5. Theoretical electronic structure of structurally modified graphene

    NASA Astrophysics Data System (ADS)

    Dvorak, Marc David

    Graphene has emerged as a promising replacement for silicon in next-generation electronics and optoelectronic devices. If graphene is to be used in semiconductor devices, however, it must acquire an electronic band gap. Numerous approaches have been proposed to control the band gap of graphene, including the periodic patterning of defects. However, the mechanism for band gap opening and the associated physics in graphene patterned with defects remain unclear. Using both analytic theory and first-principles calculations, we show that periodic patterning of defects on graphene can open a large and tunable band gap, induce strong absorption peaks at optical wavelengths, and host a giant band gap quantum spin Hall phase. First, a geometric rule is analytically derived for the arrangements of defects that open a band gap in graphene, with one ninth of all possible patterns opening a band gap. Next, we perform ab-initio density functional calculations to compare the effects of structural vacancies, hexagonal BN dopants, and passivants on the electronic structure of graphene. Qualitatively, these three types of structural defects behave the same, with only slight differences in their resulting band structures. By adjusting the shape of structural defects, we show how to move the Dirac cones in reciprocal space in accordance with the tight-binding model for the anisotropic honeycomb lattice, while the fundamental mechanism for band gap opening remains the same. To quantitatively predict the band gap and optical properties of these materials, we employ many-body perturbation theory with Green's functions (GW/Bethe-Salpeter equation) to directly include electron-electron and electron-hole interactions. Structurally modified graphene shows a strong renormalization of the fundamental band gap over single particle descriptions, and a strong electron-hole interaction as indicated by strong exciton binding energies (> 0.5 eV). Finally, we show that structurally modified graphene

  6. Protein Structure Databases.

    PubMed

    Laskowski, Roman A

    2016-01-01

    Web-based protein structure databases come in a wide variety of types and levels of information content. Those having the most general interest are the various atlases that describe each experimentally determined protein structure and provide useful links, analyses, and schematic diagrams relating to its 3D structure and biological function. Also of great interest are the databases that classify 3D structures by their folds as these can reveal evolutionary relationships which may be hard to detect from sequence comparison alone. Related to these are the numerous servers that compare folds-particularly useful for newly solved structures, and especially those of unknown function. Beyond these are a vast number of databases for the more specialized user, dealing with specific families, diseases, structural features, and so on. PMID:27115626

  7. Analysis of Geological Structures

    NASA Astrophysics Data System (ADS)

    Price, Neville J.; Cosgrove, John W.

    1990-08-01

    A knowledge of structural geology is fundamental to understanding the processes by which the earth's crust has evolved. It is a subject of fundamental importance to students of geology, experienced field geologists and academic researchers as well as to petroleum and mining engineers. In contrast to many structural textbooks which dwell upon geometrical descriptions of geological structures, this book emphasises mechanical principles and the way in which they can be used to understand how and why a wide range of geological structures develop. Structures on all scales are considered but the emphasis of the book is on those that can be seen on the scale of hand specimen or outcrop. Drawing on their considerable teaching experience the authors present a coherent and lucid analysis of geological structures which will be welcomed by a wide variety of earth scientists.

  8. Control of flexible structures

    NASA Technical Reports Server (NTRS)

    Russell, R. A.

    1985-01-01

    The requirements for future space missions indicate that many of these spacecraft will be large, flexible, and in some applications, require precision geometries. A technology program that addresses the issues associated with the structure/control interactions for these classes of spacecraft is discussed. The goal of the NASA control of flexible structures technology program is to generate a technology data base that will provide the designer with options and approaches to achieve spacecraft performance such as maintaining geometry and/or suppressing undesired spacecraft dynamics. This technology program will define the appropriate combination of analysis, ground testing, and flight testing required to validate the structural/controls analysis and design tools. This work was motivated by a recognition that large minimum weight space structures will be required for many future missions. The tools necessary to support such design included: (1) improved structural analysis; (2) modern control theory; (3) advanced modeling techniques; (4) system identification; and (5) the integration of structures and controls.

  9. Optimization of aerospace structures

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Patnaik, Surya N.

    1994-01-01

    Research carried out is grouped under two topics: (1) Design Optimization, and (2) Integrated Force Method of Analysis. Design Optimization Research Topics are singularity alleviation enhances structural optimization methods, computer based design capability extended through substructure synthesis, and optimality criteria provides optimum design for a select class of structural problems. Integrated Force Method of Analysis Research Topics are boundary compatibility formulation improves stress analysis of shell structures. Brief descriptions of the four topics are appended.

  10. Structures and Acoustics Division

    NASA Technical Reports Server (NTRS)

    Acquaviva, Cynthia S.

    1999-01-01

    The Structures and Acoustics Division of NASA Glenn Research Center is an international leader in rotating structures, mechanical components, fatigue and fracture, and structural aeroacoustics. Included are disciplines related to life prediction and reliability, nondestructive evaluation, and mechanical drive systems. Reported are a synopsis of the work and accomplishments reported by the Division during the 1996 calendar year. A bibliography containing 42 citations is provided.

  11. BOMB STABILIZING STRUCTURE

    DOEpatents

    Kelley, J.L.; Runyan, C.E.

    1963-12-10

    A stabilizinig structure capable of minimizing deviations of a falling body such as a bomb from desired trajectory is described. The structure comprises a fin or shroud arrangement of double-wedge configuration, the feeding portion being of narrow wedge shape and the after portion being of a wider wedge shape. The structure provides a force component for keeping the body on essentially desired trajectory throughout its fall. (AEC)

  12. Catalytic distillation structure

    DOEpatents

    Smith, L.A. Jr.

    1984-04-17

    Catalytic distillation structure is described for use in reaction distillation columns, and provides reaction sites and distillation structure consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and is present with the catalyst component in an amount such that the catalytic distillation structure consists of at least 10 volume % open space. 10 figs.

  13. Structures and Acoustics Division

    NASA Technical Reports Server (NTRS)

    Acquaviva, Cynthia S.

    2001-01-01

    The Structures and Acoustics Division of the NASA Glenn Research Center is an international leader in rotating structures, mechanical components, fatigue and fracture, and structural aeroacoustics. Included in this report are disciplines related to life prediction and reliability, nondestructive evaluation, and mechanical drive systems. Reported is a synopsis of the work and accomplishments completed by the Division during the 1997, 1998, and 1999 calendar years. A bibliography containing 93 citations is provided.

  14. Structural assembly in space

    NASA Technical Reports Server (NTRS)

    Stokes, J. W.; Pruett, E. C.

    1980-01-01

    A cost algorithm for predicting assembly costs for large space structures is given. Assembly scenarios are summarized which describe the erection, deployment, and fabrication tasks for five large space structures. The major activities that impact total costs for structure assembly from launch through deployment and assembly to scientific instrument installation and checkout are described. Individual cost elements such as assembly fixtures, handrails, or remote minipulators are also presented.

  15. Space station structures development

    NASA Technical Reports Server (NTRS)

    Teller, V. B.

    1986-01-01

    A study of three interrelated tasks focusing on deployable Space Station truss structures is discussed. Task 1, the development of an alternate deployment system for linear truss, resulted in the preliminary design of an in-space reloadable linear motor deployer. Task 2, advanced composites deployable truss development, resulted in the testing and evaluation of composite materials for struts used in a deployable linear truss. Task 3, assembly of structures in space/erectable structures, resulted in the preliminary design of Space Station pressurized module support structures. An independent, redundant support system was developed for the common United States modules.

  16. Structural building response review

    SciTech Connect

    Not Available

    1980-01-15

    The integrity of a nuclear power plant during a postulated seismic event is required to protect the public against radiation. Therefore, a detailed set of seismic analyses of various structures and equipment is performed while designing a nuclear power plant. This report describes the structural response analysis method, including the structural model, soil-structure interaction as it relates to structural models, methods for seismic structural analysis, numerical integration methods, methods for non-seismic response analysis approaches for various response combinations, structural damping values, nonlinear response, uncertainties in structural properties, and structural response analysis using random properties. The report describes the state-of-the-art in these areas for nuclear power plants. It also details the past studies made at Sargent and Lundy to evaluate different alternatives and the conclusions reached for the specific purposes that those studies were intended. These results were incorporated here because they fall into the general scope of this report. The scope of the present task does not include performing new calculations.

  17. Structure of human adenovirus

    SciTech Connect

    Nemerow, Glen R.; Stewart, Phoebe L.; Reddy, Vijay S.

    2012-07-11

    A detailed structural analysis of the entire human adenovirus capsid has been stymied by the complexity and size of this 150 MDa macromolecular complex. Over the past 10 years, the steady improvements in viral genome manipulation concomitant with advances in crystallographic techniques and data processing software has allowed structure determination of this virus by X-ray diffraction at 3.5 {angstrom} resolution. The virus structure revealed the location, folds, and interactions of major and minor (cement proteins) on the inner and outer capsid surface. This new structural information sheds further light on the process of adenovirus capsid assembly and virus-host cell interactions.

  18. Integrated structural health monitoring.

    SciTech Connect

    Farrar, C. R.

    2001-01-01

    Structural health monitoring is the implementation of a damage detection strategy for aerospace, civil and mechanical engineering infrastructure. Typical damage experienced by this infrastructure might be the development of fatigue cracks, degradation of structural connections, or bearing wear in rotating machinery. The goal of the research effort reported herein is to develop a robust and cost-effective structural health monitoring solution by integrating and extending technologies from various engineering and information technology disciplines. It is the authors opinion that all structural health monitoring systems must be application specific. Therefore, a specific application, monitoring welded moment resisting steel frame connections in structures subjected to seismic excitation, is described along with the motivation for choosing this application. The structural health monitoring solution for this application will integrate structural dynamics, wireless data acquisition, local actuation, micro-electromechanical systems (MEMS) technology, and statistical pattern recognition algorithms. The proposed system is based on an assessment of the deficiencies associated with many current structural health monitoring technologies including past efforts by the authors. This paper provides an example of the integrated approach to structural health monitoring being undertaken at Los Alamos National Laboratory and summarizes progress to date on various aspects of the technology development.

  19. Integrated structural health monitoring

    NASA Astrophysics Data System (ADS)

    Farrar, Charles R.; Sohn, Hoon; Fugate, Michael L.; Czarnecki, Jerry J.

    2001-07-01

    Structural health monitoring is the implementation of a damage detection strategy for aerospace, civil and mechanical engineering infrastructure. Typical damage experienced by this infrastructure might be the development of fatigue cracks, degradation of structural connections, or bearing wear in rotating machinery. The goal of the research effort reported herein is to develop a robust and cost-effective structural health monitoring solution by integrating and extending technologies from various engineering and information technology disciplines. It is the author's opinion that all structural health monitoring systems must be application specific. Therefore, a specific application, monitoring welded moment resisting steel frame connections in structures subjected to seismic excitation, is described along with the motivation for choosing this application. The structural health monitoring solution for this application will integrate structural dynamics, wireless data acquisition, local actuation, micro-electromechanical systems (MEMS) technology, and statistical pattern recognition algorithms. The proposed system is based on an assessment of the deficiencies associated with many current structural health monitoring technologies including past efforts by the authors. This paper provides an example of the integrated approach to structural health monitoring being undertaken at Los Alamos National Laboratory and summarizes progress to date on various aspects of the technology development.

  20. Deployable Soft Composite Structures.

    PubMed

    Wang, Wei; Rodrigue, Hugo; Ahn, Sung-Hoon

    2016-01-01

    Deployable structure composed of smart materials based actuators can reconcile its inherently conflicting requirements of low mass, good shape adaptability, and high load-bearing capability. This work describes the fabrication of deployable structures using smart soft composite actuators combining a soft matrix with variable stiffness properties and hinge-like movement through a rigid skeleton. The hinge actuator has the advantage of being simple to fabricate, inexpensive, lightweight and simple to actuate. This basic actuator can then be used to form modules capable of different types of deformations, which can then be assembled into deployable structures. The design of deployable structures is based on three principles: design of basic hinge actuators, assembly of modules and assembly of modules into large-scale deployable structures. Various deployable structures such as a segmented triangular mast, a planar structure comprised of single-loop hexagonal modules and a ring structure comprised of single-loop quadrilateral modules were designed and fabricated to verify this approach. Finally, a prototype for a deployable mirror was developed by attaching a foldable reflective membrane to the designed ring structure and its functionality was tested by using it to reflect sunlight onto to a small-scale solar panel. PMID:26892762

  1. Deployable Soft Composite Structures

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Rodrigue, Hugo; Ahn, Sung-Hoon

    2016-02-01

    Deployable structure composed of smart materials based actuators can reconcile its inherently conflicting requirements of low mass, good shape adaptability, and high load-bearing capability. This work describes the fabrication of deployable structures using smart soft composite actuators combining a soft matrix with variable stiffness properties and hinge-like movement through a rigid skeleton. The hinge actuator has the advantage of being simple to fabricate, inexpensive, lightweight and simple to actuate. This basic actuator can then be used to form modules capable of different types of deformations, which can then be assembled into deployable structures. The design of deployable structures is based on three principles: design of basic hinge actuators, assembly of modules and assembly of modules into large-scale deployable structures. Various deployable structures such as a segmented triangular mast, a planar structure comprised of single-loop hexagonal modules and a ring structure comprised of single-loop quadrilateral modules were designed and fabricated to verify this approach. Finally, a prototype for a deployable mirror was developed by attaching a foldable reflective membrane to the designed ring structure and its functionality was tested by using it to reflect sunlight onto to a small-scale solar panel.

  2. Neutron reflecting supermirror structure

    DOEpatents

    Wood, James L.

    1992-01-01

    An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. One layer of each set of bilayers consist of titanium, and the second layer of each set of bilayers consist of an alloy of nickel with carbon interstitially present in the nickel alloy.

  3. Deployable Soft Composite Structures

    PubMed Central

    Wang, Wei; Rodrigue, Hugo; Ahn, Sung-Hoon

    2016-01-01

    Deployable structure composed of smart materials based actuators can reconcile its inherently conflicting requirements of low mass, good shape adaptability, and high load-bearing capability. This work describes the fabrication of deployable structures using smart soft composite actuators combining a soft matrix with variable stiffness properties and hinge-like movement through a rigid skeleton. The hinge actuator has the advantage of being simple to fabricate, inexpensive, lightweight and simple to actuate. This basic actuator can then be used to form modules capable of different types of deformations, which can then be assembled into deployable structures. The design of deployable structures is based on three principles: design of basic hinge actuators, assembly of modules and assembly of modules into large-scale deployable structures. Various deployable structures such as a segmented triangular mast, a planar structure comprised of single-loop hexagonal modules and a ring structure comprised of single-loop quadrilateral modules were designed and fabricated to verify this approach. Finally, a prototype for a deployable mirror was developed by attaching a foldable reflective membrane to the designed ring structure and its functionality was tested by using it to reflect sunlight onto to a small-scale solar panel. PMID:26892762

  4. Flexible Volumetric Structure

    NASA Technical Reports Server (NTRS)

    Cagle, Christopher M. (Inventor); Schlecht, Robin W. (Inventor)

    2014-01-01

    A flexible volumetric structure has a first spring that defines a three-dimensional volume and includes a serpentine structure elongatable and compressible along a length thereof. A second spring is coupled to at least one outboard edge region of the first spring. The second spring is a sheet-like structure capable of elongation along an in-plane dimension thereof. The second spring is oriented such that its in-plane dimension is aligned with the length of the first spring's serpentine structure.

  5. Adaptive structures to enable ground test validation of precision structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Fanson, James F.; Chen, Gun-Shing; Kuo, Chin-Po

    1990-01-01

    The use of analytical models and ground-based experimental validation of precision space structures is addressed. The application of adaptive structures to such validation of precision space structures is addressed, with the focus on adaptive truss structures.

  6. Stable umbral chromospheric structures

    NASA Astrophysics Data System (ADS)

    Henriques, V. M. J.; Scullion, E.; Mathioudakis, M.; Kiselman, D.; Gallagher, P. T.; Keenan, F. P.

    2015-02-01

    Aims: We seek to understand the morphology of the chromosphere in sunspot umbra. We investigate if the horizontal structures observed in the spectral core of the Ca II H line are ephemeral visuals caused by the shock dynamics of more stable structures, and examine their relationship with observables in the H-alpha line. Methods: Filtergrams in the core of the Ca II H and H-alpha lines as observed with the Swedish 1-m Solar Telescope are employed. We utilise a technique that creates composite images and tracks the flash propagation horizontally. Results: We find 0.̋15 wide horizontal structures, in all of the three target sunspots, for every flash where the seeing is moderate to good. Discrete dark structures are identified that are stable for at least two umbral flashes, as well as systems of structures that live for up to 24 min. We find cases of extremely extended structures with similar stability, with one such structure showing an extent of 5''. Some of these structures have a correspondence in H-alpha, but we were unable to find a one-to-one correspondence for every occurrence. If the dark streaks are formed at the same heights as umbral flashes, there are systems of structures with strong departures from the vertical for all three analysed sunspots. Conclusions: Long-lived Ca II H filamentary horizontal structures are a common and likely ever-present feature in the umbra of sunspots. If the magnetic field in the chromosphere of the umbra is indeed aligned with the structures, then the present theoretical understanding of the typical umbra needs to be revisited. Movies associated to Figs. 3 and 4 are available in electronic form at http://www.aanda.org

  7. Structural sizing considerations for large space structures

    NASA Technical Reports Server (NTRS)

    Heard, W. L., Jr.; Bush, H. G.; Walz, J. E.

    1981-01-01

    A number of missions for the space shuttle were proposed which involve placing large truss platforms on-orbit. These platforms range in size from tens of meters in span for reflector application to several thousand meters for solar power collector application. These proposed sizes and the operational requirements considered are unconventional in comparison to Earthbound structures and little information exists concerning efficient proportions of the structural elements forming the framework of the platforms. Such proportions are of major concern because they have a strong influence on the packaging efficiency and, thus, the transportation effectiveness of the shuttle. The present study is undertaken to: (1) identify efficient ranges of application of deployable and erectable platforms configured for shuttle transport to orbit, and (2) determine sensitivity to key parameters of minimum mass deployable and erectable platform designs.

  8. Tapered structure construction

    DOEpatents

    Smith, Eric D.; Takata, Rosalind K.; Slocum, Alexander H.; Nayfeh, Samir A.

    2016-04-05

    Feeding stock used to form a tapered structure into a curving device such that each point on the stock undergoes rotational motion about a peak location of the tapered structure; and the stock meets a predecessor portion of stock along one or more adjacent edges.

  9. Generalized holomorphic structures

    NASA Astrophysics Data System (ADS)

    Wang, Yicao

    2014-12-01

    We define the notion of generalized holomorphic principal bundles and establish that their associated vector bundles of holomorphic representations are generalized holomorphic vector bundles defined by M. Gualtieri. Motivated by our definition, several examples of generalized holomorphic structures are constructed. A reduction theorem of generalized holomorphic structures is also included.

  10. Calcium silicate insulation structure

    DOEpatents

    Kollie, Thomas G.; Lauf, Robert J.

    1995-01-01

    An insulative structure including a powder-filled evacuated casing utilizes a quantity of finely divided synthetic calcium silicate having a relatively high surface area. The resultant structure-provides superior thermal insulating characteristics over a broad temperature range and is particularly well-suited as a panel for a refrigerator or freezer or the insulative barrier for a cooler or a insulated bottle.

  11. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, R. G.; Wiberley, S. E.

    1985-01-01

    Various topics relating to composite structural materials for use in aircraft structures are discussed. The mechanical properties of high performance carbon fibers, carbon fiber-epoxy interface bonds, composite fractures, residual stress in high modulus and high strength carbon fibers, fatigue in composite materials, and the mechanical properties of polymeric matrix composite laminates are among the topics discussed.

  12. Organisational Structure & Change

    ERIC Educational Resources Information Center

    National Centre for Vocational Education Research (NCVER), 2006

    2006-01-01

    Structural change is seen as a way to meet the challenges of the future that face many organisations. While some writers agree that broad-ranging structural change may not always transform an organisation or enhance its performance, others claim that innovation will be a major source of competitive advantage to organisations, particularly when…

  13. The Cambridge Structural Database

    PubMed Central

    Groom, Colin R.; Bruno, Ian J.; Lightfoot, Matthew P.; Ward, Suzanna C.

    2016-01-01

    The Cambridge Structural Database (CSD) contains a complete record of all published organic and metal–organic small-molecule crystal structures. The database has been in operation for over 50 years and continues to be the primary means of sharing structural chemistry data and knowledge across disciplines. As well as structures that are made public to support scientific articles, it includes many structures published directly as CSD Communications. All structures are processed both computationally and by expert structural chemistry editors prior to entering the database. A key component of this processing is the reliable association of the chemical identity of the structure studied with the experimental data. This important step helps ensure that data is widely discoverable and readily reusable. Content is further enriched through selective inclusion of additional experimental data. Entries are available to anyone through free CSD community web services. Linking services developed and maintained by the CCDC, combined with the use of standard identifiers, facilitate discovery from other resources. Data can also be accessed through CCDC and third party software applications and through an application programming interface. PMID:27048719

  14. Fabricating Structural Beams

    NASA Technical Reports Server (NTRS)

    Engler, E. E.; Ehl, J.; Muench, W.; Morfin, H.; Huber, J.; Braun, R.; Marx, W.; Alberi, A.; Romaneck, R.; Johnson, C.; Giannuzzi, O.; Weyhreter, A.

    1982-01-01

    Automatic machine described in new report has demonstrated on Earth feasibility of machine fabricating beams for huge structures in space. Such structures include solar mirrors, radiometer reflectors, microwave power transmitters, solar-thermal power generators, and solar photoelectric generators, ranging in size from few hundred meters long to tens of kilometers long.

  15. Agricultural Structures, Volume II.

    ERIC Educational Resources Information Center

    Linhardt, Richard E.; Burhoe, Steve

    This guide to a curriculum unit in agricultural structures is designed to expand the curriculum materials available in vocational agriculture in Missouri. It and Agricultural Structures I (see note) provide reference materials to systematize the curriculum. The six units cover working with concrete (19 lessons, 2 laboratory exercises), drawing and…

  16. Ecological Structure Activity Relationships

    EPA Science Inventory

    Ecological Structure Activity Relationships, v1.00a, February 2009
    ECOSAR (Ecological Structure Activity Relationships) is a personal computer software program that is used to estimate the toxicity of chemicals used in industry and discharged into water. The program predicts...

  17. Structure of Skeletal Muscle

    MedlinePlus

    ... Cells, Tissues, & Membranes Cell Structure & Function Cell Structure Cell Function Body Tissues Epithelial Tissue Connective Tissue Muscle Tissue ... nerves. This is directly related to the primary function of skeletal muscle, ... an impulse from a nerve cell. Generally, an artery and at least one vein ...

  18. Piaget's Structural Developmental Psychology.

    ERIC Educational Resources Information Center

    Broughton, John M.

    1981-01-01

    Piaget's theory is identified as a branch of structuralism concerned with the concept of truth, in distinction from French structuralism, which is focused on meaning. The two branches are compared and contrasted, and relations between logic and language are explored. Similarities and differences in the theories of Piaget, Levi-Strauss, and Chomsky…

  19. Space Station structures

    NASA Astrophysics Data System (ADS)

    Schneider, W.

    1985-04-01

    A brief overview of some structural results that came from space station skunk works is presented. Detailed drawings of the pressurized modules, and primary truss structures such as deployable single fold beams, erectable beams and deployable double folds are given. Typical truss attachment devices and deployable backup procedures are also given.

  20. Space Station structures

    NASA Technical Reports Server (NTRS)

    Schneider, W.

    1985-01-01

    A brief overview of some structural results that came from space station skunk works is presented. Detailed drawings of the pressurized modules, and primary truss structures such as deployable single fold beams, erectable beams and deployable double folds are given. Typical truss attachment devices and deployable backup procedures are also given.

  1. The Structure of Reciprocity

    ERIC Educational Resources Information Center

    Molm, Linda D.

    2010-01-01

    Reciprocity is one of the defining features of social exchange and social life, yet exchange theorists have tended to take it for granted. Drawing on work from a decade-long theoretical research program, I argue that reciprocity is structured and variable across different forms of exchange, that these variations in the structure of reciprocity…

  2. Masses and Structure

    SciTech Connect

    Cakirli, R. B.; Casten, R. F.

    2010-08-04

    The use of nuclear masses to elucidate structure and its evolution with Z and N is discussed, with emphasis on two-neutron separation energies and the proton-neutron interaction as extracted from double differences of binding energies. The enhanced sensitivity of masses to structure in deformed nuclei is also discussed.

  3. The Cambridge Structural Database.

    PubMed

    Groom, Colin R; Bruno, Ian J; Lightfoot, Matthew P; Ward, Suzanna C

    2016-04-01

    The Cambridge Structural Database (CSD) contains a complete record of all published organic and metal-organic small-molecule crystal structures. The database has been in operation for over 50 years and continues to be the primary means of sharing structural chemistry data and knowledge across disciplines. As well as structures that are made public to support scientific articles, it includes many structures published directly as CSD Communications. All structures are processed both computationally and by expert structural chemistry editors prior to entering the database. A key component of this processing is the reliable association of the chemical identity of the structure studied with the experimental data. This important step helps ensure that data is widely discoverable and readily reusable. Content is further enriched through selective inclusion of additional experimental data. Entries are available to anyone through free CSD community web services. Linking services developed and maintained by the CCDC, combined with the use of standard identifiers, facilitate discovery from other resources. Data can also be accessed through CCDC and third party software applications and through an application programming interface. PMID:27048719

  4. Inflatable Column Structure

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1985-01-01

    Lightweight structural member easy to store. Billowing between circumferential loops of fiber inflated column becomes series of cells. Each fiber subjected to same tension along entire length (though tension is different in different fibers). Member is called "isotensoid" column. Serves as jack for automobiles or structures during repairs. Also used as support for temporary bleachers or swimming pools.

  5. The Structures of Life.

    ERIC Educational Resources Information Center

    National Inst. of General Medical Sciences (NIH), Bethesda, MD.

    This booklet, geared toward an advanced high school or early college-level audience, explains how structural biology provides insight into health and disease and is useful in developing new medications. This publication contains a general introduction to proteins, coverage of the techniques used to determine protein structures, and a chapter on…

  6. Kernel structures for Clouds

    NASA Technical Reports Server (NTRS)

    Spafford, Eugene H.; Mckendry, Martin S.

    1986-01-01

    An overview of the internal structure of the Clouds kernel was presented. An indication of how these structures will interact in the prototype Clouds implementation is given. Many specific details have yet to be determined and await experimentation with an actual working system.

  7. Frontiers of Nuclear Structure

    SciTech Connect

    Nazarewicz, Witold

    1997-12-31

    Current developments in nuclear structure at the `limits` are discussed. The studies of nuclear behavior at extreme conditions provide us with invaluable information about the nature of the nuclear interaction and nucleonic correlations at various energy-distance scales. In this talk frontiers of nuclear structure are briefly reviewed from a theoretical perspective, mainly concentrating on medium-mass and heavy nuclei.

  8. Structurally abnormal human autosomes

    SciTech Connect

    1993-12-31

    Chapter 25, discusses structurally abnormal human autosomes. This discussion includes: structurally abnormal chromosomes, chromosomal polymorphisms, pericentric inversions, paracentric inversions, deletions or partial monosomies, cri du chat (cat cry) syndrome, ring chromosomes, insertions, duplication or pure partial trisomy and mosaicism. 71 refs., 8 figs.

  9. Defining structural limit zones

    NASA Technical Reports Server (NTRS)

    Merchant, D. H.

    1978-01-01

    Method for defining limit loads uses probability distribution of largest load occurring during given time intervals. Method is compatible with both deterministic and probabilistic structural design criteria. It also rationally accounts for fact that longer structure is exposed to random loading environment, greater is possibility that it will experience extreme load.

  10. The Changing Family Structure.

    ERIC Educational Resources Information Center

    Bernard van Leer Foundation Newsletter, 1993

    1993-01-01

    This newsletter issue contains feature articles and short reports on how and why family structures are undergoing substantial change in many parts of the world. These articles include: (1) "The Changing Family Structure," a review of how families are changing and why; (2) "Peru: Families in the Andes"; (3) "Thailand: Families of the Garbage Dump";…

  11. Boston Infill Schools.

    ERIC Educational Resources Information Center

    Stull, Don; Heder, Lajos

    Concepts and recommendations are presented regarding a proposed system of dispersed classroom clusters or 'infill schools'. These small independent urban schools would be housed in prefabricated structures developed for infill housing in Boston. The infill unit uses pre-designed building components and can be constructed in a few weeks. The infill…

  12. Using Computer-Aided Design Software and 3D Printers to Improve Spatial Visualization

    ERIC Educational Resources Information Center

    Katsio-Loudis, Petros; Jones, Millie

    2015-01-01

    Many articles have been published on the use of 3D printing technology. From prefabricated homes and outdoor structures to human organs, 3D printing technology has found a niche in many fields, but especially education. With the introduction of AutoCAD technical drawing programs and now 3D printing, learners can use 3D printed models to develop…

  13. Adaptive structures: some materials and structural issues

    NASA Astrophysics Data System (ADS)

    Roberts, Donald; Lloyd, Peter A.; Hopgood, P.; Mahon, Steve W.; Bowles, A. R.

    2000-08-01

    The concept of using embedded or surface-bonded solid-state actuators to effect shape change in carbon fibre composite laminates continues to have technical merit and appeal. Conventional laminate design methods tend to lead to stiff structures, whilst it is easiest to impose a change of shape on a compliant structure. This presents a possible conflict of design and suggests that the useful performance of solid- state actuators will always be limited by the stiffness of the host laminate. One possible solution is to increase the in-plane work capacity of the actuators either by using improved materials such as phase change perovskites like PLZT or improved eletroding techniques such as inter-digitated electrodes (IDEs). In this study, the performance of several different actuator/laminate systems have been modelled to determine a baseline capability in pure bending. Four cases have been considered for different panel thicknesses and lay-up sequences. The materials performance and IDE design issues have also been addressed. Modelling indicates that even with conventional actuator materials, structural displacements can be produced which could provide useful shape change in applications such as missile roll control.

  14. Regularized Structural Equation Modeling

    PubMed Central

    Jacobucci, Ross; Grimm, Kevin J.; McArdle, John J.

    2016-01-01

    A new method is proposed that extends the use of regularization in both lasso and ridge regression to structural equation models. The method is termed regularized structural equation modeling (RegSEM). RegSEM penalizes specific parameters in structural equation models, with the goal of creating easier to understand and simpler models. Although regularization has gained wide adoption in regression, very little has transferred to models with latent variables. By adding penalties to specific parameters in a structural equation model, researchers have a high level of flexibility in reducing model complexity, overcoming poor fitting models, and the creation of models that are more likely to generalize to new samples. The proposed method was evaluated through a simulation study, two illustrative examples involving a measurement model, and one empirical example involving the structural part of the model to demonstrate RegSEM’s utility. PMID:27398019

  15. Inflatable nested toroid structure

    NASA Technical Reports Server (NTRS)

    Johnson, Christopher J. (Inventor); Raboin, Jasen L. (Inventor); Spexarth, Gary R. (Inventor)

    2011-01-01

    An inflatable structure comprises at least two generally toroidal, inflatable modules. When in a deployed mode, the first, inner module has a major diameter less than that of a second, outer module and is positioned within the inner circumference of the outer module such that the first module is nested circumferentially alongside the second module. The inflatable structure, in a non-deployed, non-inflated mode, is of compact configuration and adapted to be transported to a site of deployment. When deployed, the inflatable structure is of substantially increased interior volume. In one embodiment, access between the interior of the first module and the second module is provided by at least one port or structural pass-through. In another embodiment, the inflatable structure includes at least one additional generally toroidal module external of and circumferentially surrounding the second module.

  16. Iconicity as structure mapping

    PubMed Central

    Emmorey, Karen

    2014-01-01

    Linguistic and psycholinguistic evidence is presented to support the use of structure-mapping theory as a framework for understanding effects of iconicity on sign language grammar and processing. The existence of structured mappings between phonological form and semantic mental representations has been shown to explain the nature of metaphor and pronominal anaphora in sign languages. With respect to processing, it is argued that psycholinguistic effects of iconicity may only be observed when the task specifically taps into such structured mappings. In addition, language acquisition effects may only be observed when the relevant cognitive abilities are in place (e.g. the ability to make structural comparisons) and when the relevant conceptual knowledge has been acquired (i.e. information key to processing the iconic mapping). Finally, it is suggested that iconicity is better understood as a structured mapping between two mental representations than as a link between linguistic form and human experience. PMID:25092669

  17. Spin structure functions

    SciTech Connect

    Jian-ping Chen, Alexandre Deur, Sebastian Kuhn, Zein-eddine Meziani

    2011-06-01

    Spin-dependent observables have been a powerful tool to probe the internal structure of the nucleon and to understand the dynamics of the strong interaction. Experiments involving spin degrees of freedom have often brought out surprises and puzzles. The so-called "spin crisis" in the 1980s revealed the limitation of naive quark-parton models and led to intensive worldwide efforts, both experimental and theoretical, to understand the nucleon spin structure. With high intensity and high polarization of both the electron beam and targets, Jefferson Lab has the world's highest polarized luminosity and the best figure-of-merit for precision spin structure measurements. It has made a strong impact in this subfield of research. This chapter will highlight Jefferson Lab's unique contributions in the measurements of valence quark spin distributions, in the moments of spin structure functions at low to intermediate Q2, and in the transverse spin structure.

  18. Optoelectronic Mounting Structure

    DOEpatents

    Anderson, Gene R.; Armendariz, Marcelino G.; Baca, Johnny R. F.; Bryan, Robert P.; Carson, Richard F.; Chu, Dahwey; Duckett, III, Edwin B.; McCormick, Frederick B.; Peterson, David W.; Peterson, Gary D.; Reber, Cathleen A.; Reysen, Bill H.

    2004-10-05

    An optoelectronic mounting structure is provided that may be used in conjunction with an optical transmitter, receiver or transceiver module. The mounting structure may be a flexible printed circuit board. Thermal vias or heat pipes in the head region may transmit heat from the mounting structure to the heat spreader. The heat spreader may provide mechanical rigidity or stiffness to the heat region. In another embodiment, an electrical contact and ground plane may pass along a surface of the head region so as to provide an electrical contact path to the optoelectronic devices and limit electromagnetic interference. In yet another embodiment, a window may be formed in the head region of the mounting structure so as to provide access to the heat spreader. Optoelectronic devices may be adapted to the heat spreader in such a manner that the devices are accessible through the window in the mounting structure.

  19. Flow measuring structures

    NASA Astrophysics Data System (ADS)

    Boiten, W.

    1993-11-01

    The use of flow measuring structures is one of the various methods for the continuous measurement of discharges in open channels. In this report a brief summary of these methods is presented to get some insight in the selection of the most appropriate method. Then the distinct functions of water control structures are described. The flow measuring structures are classified according to international rules. The fields of application are dealt with and the definitions of weir flow are given. Much attention is paid to the aspects of how to select the most suitable flow measuring structure. The accuracy in the evaluation of the discharge has been related to the different error sources. A review of international standards on flow measuring structures concludes the report.

  20. Electron Structure of Francium

    NASA Astrophysics Data System (ADS)

    Koufos, Alexander

    2012-02-01

    This talk presents the first calculations of the electronic structure of francium for the bcc, fcc and hcp structures, using the Augmented Plane Wave (APW) method in its muffin-tin and linearized general potential forms. Both the Local Density Approximation (LDA) and Generalized Gradient Approximation (GGA), were used to calculate the electronic structure and total energy of francium (Fr). The GGA and LDA both found the total energy of the hcp structure slightly below that of the fcc and bcc structure, respectively. This is in agreement with similar results for the other alkali metals using the same methodology. The equilibrium lattice constant, bulk modulus and superconductivity parameters were calculated. We found that under pressures, in the range of 1-5 GPa, Fr could be a superconductor at a critical temperature of about 4K.

  1. Iconicity as structure mapping.

    PubMed

    Emmorey, Karen

    2014-09-19

    Linguistic and psycholinguistic evidence is presented to support the use of structure-mapping theory as a framework for understanding effects of iconicity on sign language grammar and processing. The existence of structured mappings between phonological form and semantic mental representations has been shown to explain the nature of metaphor and pronominal anaphora in sign languages. With respect to processing, it is argued that psycholinguistic effects of iconicity may only be observed when the task specifically taps into such structured mappings. In addition, language acquisition effects may only be observed when the relevant cognitive abilities are in place (e.g. the ability to make structural comparisons) and when the relevant conceptual knowledge has been acquired (i.e. information key to processing the iconic mapping). Finally, it is suggested that iconicity is better understood as a structured mapping between two mental representations than as a link between linguistic form and human experience. PMID:25092669

  2. Trends in aerospace structures

    NASA Technical Reports Server (NTRS)

    Card, M. F.

    1978-01-01

    Recent developments indicate that there may soon be a revolution in aerospace structures. Increases in allowable operational stress levels, utilization of high-strength, high-toughness materials, and new structural concepts will highlight this advancement. Improved titanium and aluminum alloys and high-modulus, high-strength advanced composites, with higher specific properties than aluminum and high-strength nickel alloys, are expected to be the principal materials. Significant advances in computer technology will cause major changes in the preliminary design cycle and permit solutions of otherwise too-complex interactive structural problems and thus the development of vehicles and components of higher performance. The energy crisis will have an impact on material costs and choices and will spur the development of more weight-efficient structures. There will also be significant spinoffs of aerospace structures technology, particularly in composites and design/analysis software.

  3. Solution Accounts for Structural Damping

    NASA Technical Reports Server (NTRS)

    Roussos, L. A.; Hyer, M. W.; Thornton, E. A.

    1982-01-01

    New analytical technique determines dynamic response of damped structures dominated by internal structural damping mechanisms. Though structural damping is often negligible compared with damping due to air friction and friction in joints, structural damping can be of major importance in structures having heavy damping treatments or in outer-space structures. Finite-element model includes nonlinear, nonviscous internal damping.

  4. Fundamentals of Structural Geology

    NASA Astrophysics Data System (ADS)

    Pollard, David D.; Fletcher, Raymond C.

    2005-09-01

    Fundamentals of Structural Geology provides a new framework for the investigation of geological structures by integrating field mapping and mechanical analysis. Assuming a basic knowledge of physical geology, introductory calculus and physics, it emphasizes the observational data, modern mapping technology, principles of continuum mechanics, and the mathematical and computational skills, necessary to quantitatively map, describe, model, and explain deformation in Earth's lithosphere. By starting from the fundamental conservation laws of mass and momentum, the constitutive laws of material behavior, and the kinematic relationships for strain and rate of deformation, the authors demonstrate the relevance of solid and fluid mechanics to structural geology. This book offers a modern quantitative approach to structural geology for advanced students and researchers in structural geology and tectonics. It is supported by a website hosting images from the book, additional colour images, student exercises and MATLAB scripts. Solutions to the exercises are available to instructors. The book integrates field mapping using modern technology with the analysis of structures based on a complete mechanics MATLAB is used to visualize physical fields and analytical results and MATLAB scripts can be downloaded from the website to recreate textbook graphics and enable students to explore their choice of parameters and boundary conditions The supplementary website hosts color images of outcrop photographs used in the text, supplementary color images, and images of textbook figures for classroom presentations The textbook website also includes student exercises designed to instill the fundamental relationships, and to encourage the visualization of the evolution of geological structures; solutions are available to instructors

  5. Structure of lipid bilayers

    PubMed Central

    Nagle, John F.; Tristram-Nagle, Stephanie

    2009-01-01

    The quantitative experimental uncertainty in the structure of fully hydrated, biologically relevant, fluid (Lα) phase lipid bilayers has been too large to provide a firm base for applications or for comparison with simulations. Many structural methods are reviewed including modern liquid crystallography of lipid bilayers that deals with the fully developed undulation fluctuations that occur in the Lα phase. These fluctuations degrade the higher order diffraction data in a way that, if unrecognized, leads to erroneous conclusions regarding bilayer structure. Diffraction measurements at high instrumental resolution provide a measure of these fluctuations. In addition to providing better structural determination, this opens a new window on interactions between bilayers, so the experimental determination of interbilayer interaction parameters is reviewed briefly. We introduce a new structural correction based on fluctuations that has not been included in any previous studies. Updated measurements, such as for the area compressibility modulus, are used to provide adjustments to many of the literature values of structural quantities. Since the gel (Lβ′) phase is valuable as a stepping stone for obtaining fluid phase results, a brief review is given of the lower temperature phases. The uncertainty in structural results for lipid bilayers is being reduced and best current values are provided for bilayers of five lipids. PMID:11063882

  6. Mobile marine operations structure

    SciTech Connect

    Bhalaik, A.; Braddick, P.W.; Brittin, D.S.; Johnson, G.L.

    1987-09-22

    This patent describes the process of installing a marine operations structure in a pre-determined sea floor location. The structure has a central core and a support base having at least two differently sloped ice wall surfaces for achieving fracturing of ice features, and having at least two series of circumferentially arranged ballast tanks. It consists of positioning the structure over a selected sea floor location by the use of at least three tug boats connected to the structure by tension cables arranged radially with respect to the structure; flooding a first series of lower ballast tanks in a sequential ballasting operation; flooding a second series of ballast tanks located at a higher elevation within the structure than the first series of ballast tanks; maintaining radial forces along the tension cables during the flooding steps; and after the structure has become founded on the bottom of the sea, pumping sea waver into fluid tanks some of which are located at an elevation above the water level.

  7. Structural Model of Eumelanin

    NASA Astrophysics Data System (ADS)

    Kaxiras, Efthimios; Tsolakidis, Argyrios; Zonios, George; Meng, Sheng

    2006-11-01

    Melanin is a ubiquitous pigment in living organisms with multiple important functions, yet its structure is not well understood. We propose a structural model for eumelanin protomolecules, consisting of 4 or 5 of the basic molecular units (hydroquinone, indolequinone, and its tautomers), in arrangements that contain an inner porphyrin ring. We use time-dependent density functional theory to calculate the optical absorption spectrum of the structural model, which reproduces convincingly the main features of the experimental spectrum of eumelanin. Our model also reproduces accurately other important properties of eumelanin, including x-ray scattering data, its ability to capture and release metal ions, and the characteristic size of the protomolecules.

  8. ACEE composite structures technology

    NASA Technical Reports Server (NTRS)

    Klotzsche, M. (Compiler)

    1984-01-01

    The NASA Aircraft Energy Efficiency (ACEE) Composite Primary Aircraft Structures Program has made significant progress in the development of technology for advanced composites in commercial aircraft. Commercial airframe manufacturers have demonstrated technology readiness and cost effectiveness of advanced composites for secondary and medium primary components and have initiated a concerted program to develop the data base required for efficient application to safety-of-flight wing and fuselage structures. Oral presentations were compiled into five papers. Topics addressed include: damage tolerance and failsafe testing of composite vertical stabilizer; optimization of composite multi-row bolted joints; large wing joint demonstation components; and joints and cutouts in fuselage structure.

  9. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, R.; Wiberley, S. E.

    1986-01-01

    Overall emphasis is on basic long-term research in the following categories: constituent materials, composite materials, generic structural elements, processing science technology; and maintaining long-term structural integrity. Research in basic composition, characteristics, and processing science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to present and future problems. Detailed descriptions of the progress achieved in the various component parts of this comprehensive program are presented.

  10. Deployable geodesic truss structure

    NASA Technical Reports Server (NTRS)

    Mikulas, Martin M., Jr. (Inventor); Rhodes, Marvin D. (Inventor); Simonton, J. Wayne (Inventor)

    1987-01-01

    A deployable geodesic truss structure which can be deployed from a stowed state to an erected state is described. The truss structure includes a series of bays, each bay having sets of battens connected by longitudinal cross members which give the bay its axial and torsional stiffness. The cross members are hinged at their mid point by a joint so that the cross members are foldable for deployment or collapsing. The bays are deployed and stabilized by actuator means connected between the mid point joints of the cross members. Hinged longerons may be provided to also connect the sets of battens and to collapse for stowing with the rest of the truss structure.

  11. Fault structure, damage and acoustic emission characteristics

    NASA Astrophysics Data System (ADS)

    Dresen, G. H.; Göbel, T.; Stanchits, S.; Kwiatek, G.; Charalampidou, E. M.

    2011-12-01

    We investigate the evolution of faulting-related damage and acoustic emission activity in experiments performed on granite, quartzite and sandstone samples with 40-50 mm diameter and 100-125 mm length. Experiments were performed in a servo-controlled MTS loading frame in triaxial compression at confining pressures ranging from 20-140 MPa. We performed a series of fracture and stick-slip sliding experiments on prefractured samples. Acoustic emissions (AE) and ultrasonic velocities were monitored using up to 14 P-wave sensors glued to the cylindrical surface of the rock. Full waveforms were stored in a 16 channel transient recording system (Daxbox, PRÖKEL, Germany). Full moment tensor analysis and polarity of AE first motions were used to discriminate source types associated with tensile, shear and pore-collapse cracking. To monitor strain, two pairs of orthogonally oriented strain-gages were glued onto the specimen surface. Fracture nucleation and growth occurred from a nucleation patch mostly located at the specimen surface or at the tip of prefabricated notches inside the specimens. Irrespective of the rock type, fracture propagation is associated with formation of a damage zone surrounding the fracture surface as revealed by distribution of cracks and AE hypocenters displaying a logarithmic decay in microcrack damage with distance normal to the fault trace. The width of the damage zone varies along the fault. After fracturing, faults were locked by increasing confining pressure. Subsequent sliding was mostly induced by driving the piston at a constant displacement rate producing large single events or multiple stick-slips. With increasing sliding distance a corrugated and rough fault surface formed displaying displacement-parallel lineations. Microstructural analysis of fault surfaces and cross-sections revealed formation of multiple secondary shears progressively merging into an anastomosing 3D-network controlling damage evolution and AE activity in the fault

  12. Mesochronal Structure Learning

    PubMed Central

    Plis, Sergey; Danks, David; Yang, Jianyu

    2016-01-01

    Standard time series structure learning algorithms assume that the measurement timescale is approximately the same as the timescale of the underlying (causal) system. In many scientific contexts, however, this assumption is violated: the measurement timescale can be substantially slower than the system timescale (so intermediate time series datapoints will be missing). This assumption violation can lead to significant learning errors. In this paper, we provide a novel learning algorithm to extract system-timescale structure from measurement data that undersample the underlying system. We employ multiple algorithmic optimizations that exploit the problem structure in order to achieve computational tractability. The resulting algorithm is highly reliable at extracting system-timescale structure from undersampled data. PMID:27076793

  13. ACEE composite structures technology

    NASA Technical Reports Server (NTRS)

    James, A. M.

    1984-01-01

    Topics addressed include: strength and hygrothermal response of L-1011 fin components; wing fuel containment and damage tolerance development; impact dynamics; acoustic transmission; fuselage structure; composite transport wing technology development; spar/assembly concepts.

  14. Stratigraphy and structural geology

    NASA Technical Reports Server (NTRS)

    Carr, M. H.; Wilhelms, D. E.; Greeley, R.; Guest, J. E.

    1976-01-01

    The immediate goal of stratigraphy and structural geology is to reduce the enormous complexity of a planetary surface to comprehensible proportions by dividing the near-surface rocks into units and mapping their distribution and attitude.

  15. School Administrator Grapevine Structure.

    ERIC Educational Resources Information Center

    Licata, Joseph W.; Hack, Walter G.

    1980-01-01

    A study reveals that principals' grapevine structure shows both "guild-like" and "clan-like" grouping and reflects the patterns of occupational socialization of school principals and informal boundary spanning processes. (Author/JM)

  16. NASA Now: Inflatable Structures

    NASA Video Gallery

    NASA senior research engineer Judith Watson is one of a team of engineers at NASA’s Langley Research Center who are studying inflatable structures that might one day be used to establish an outpo...

  17. Other Fabric Structures

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Architects, engineers and building owners are turning increasingly to fabric structures because of their aesthetic appeal, relatively low initial cost, low maintenance outlays, energy efficiency and good space utilization. Several examples are shown.

  18. Stellar atmospheric structural patterns

    NASA Technical Reports Server (NTRS)

    Thomas, R. N.

    1983-01-01

    The thermodynamics of stellar atmospheres is discussed. Particular attention is given to the relation between theoretical modeling and empirical evidence. The characteristics of distinctive atmospheric regions and their radical structures are discussed.

  19. Dielectric assist accelerating structure

    NASA Astrophysics Data System (ADS)

    Satoh, D.; Yoshida, M.; Hayashizaki, N.

    2016-01-01

    A higher-order TM02 n mode accelerating structure is proposed based on a novel concept of dielectric loaded rf cavities. This accelerating structure consists of ultralow-loss dielectric cylinders and disks with irises which are periodically arranged in a metallic enclosure. Unlike conventional dielectric loaded accelerating structures, most of the rf power is stored in the vacuum space near the beam axis, leading to a significant reduction of the wall loss, much lower than that of conventional normal-conducting linac structures. This allows us to realize an extremely high quality factor and a very high shunt impedance at room temperature. A simulation of a 5 cell prototype design with an existing alumina ceramic indicates an unloaded quality factor of the accelerating mode over 120 000 and a shunt impedance exceeding 650 M Ω /m at room temperature.

  20. Bioinspired structured surfaces.

    PubMed

    Bhushan, Bharat

    2012-01-24

    Nature has evolved objects with desired functionality using commonly found materials. Nature capitalizes on hierarchical structures to achieve functionality. The understanding of the functions provided by objects and processes found in nature can guide us to produce nanomaterials, nanodevices, and processes with desirable functionality. Various natural objects which provide functionality of commercial interest have been characterized to understand how a natural object provides functionality. We have modeled and fabricated structures in the lab using nature's route and developed optimum structures. Once it is understood how nature does it, optimum structures have been fabricated using smart materials and fabrication techniques. This feature article provides an overview of four topics: Lotus effect, rose petal effect, gecko feet, and shark skin. PMID:22233136

  1. Structural Organization of DNA.

    ERIC Educational Resources Information Center

    Banfalvi, Gaspar

    1986-01-01

    Explains the structural organization of DNA by providing information on the primary, secondary, tertiary, and higher organization levels of the molecule. Also includes illustrations and descriptions of sign-inversion and rotating models for supercoiling of DNA. (ML)

  2. Structured beam diffraction.

    PubMed

    Castagna, R; Di Donato, A; Nucara, L; Xu, J H; Lucchetta, D E; Simoni, F

    2016-04-01

    We report on the observation of a modulated pattern induced by a single laser beam in a polymeric film. In spite of the simple geometrical configuration, the analysis of the far field diffraction pattern allows a sensitive retrieving of the wavelength of the recording beam and of its incidence angle, pointing out the high information content of the recorded spot. A theoretical model is presented which satisfactorily explains the observed behavior. It takes into account the interaction of structured light with structured matter with the same symmetries and spatial modulation frequencies close to each other. This result shows a feature of the interaction between structured light and structured matter which has not been explored yet. PMID:27192262

  3. Structure of the Heart

    MedlinePlus

    ... Central Nervous System Peripheral Nervous System Review Quiz Endocrine System Characteristics of Hormones Endocrine Glands & Their Hormones Pituitary & ... Thyroid & Parathyroid Glands Adrenal Gland Pancreas Gonads Other Endocrine Glands ... Cardiovascular System Heart Structure of the Heart Physiology of the ...

  4. Structure of Ice VI.

    PubMed

    Kamb, B

    1965-10-01

    Ice VI, a high-pressure form of density 1.31 g cm-(3), has a tetragonal cell of dimensions a = 6.27 A, c = 5.79 A, space group P4(2)/nmc, each cell containing ten water molecules. The structure is built up of hydrogen-bonded chdins of water molecules that are analogs of the tectosilicate chains out of which the fibrous zeolites are constructed. The chains in ice VI are linked laterally to one another to form an open, zeolite-like framework. The cavities in this framework are filled with a second framework identical with the first. The two frameworks interpenetrate but do not interconnect, and the complete structure can thus be considered a "self-clathrate." This structural feature is a natural way to achieve high density in tetrahedrally linked framework structures. PMID:17787274

  5. Determining structural performance

    NASA Technical Reports Server (NTRS)

    Ernst, Michael A.; Kiraly, Louis J.

    1987-01-01

    An overview is given of the methods and concepts developed to enhance and predict structural dynamic characteristics of advanced aeropropulsion systems. Aeroelasticity, Vibration Control, Dynamic Systems, and Computational Structural Methods are four disciplines that make up the research program at NASA/Lewis Research Center. The Aeroelasticity program develops analytical and experimental methods to minimize flutter and forced vibration of aerospace propulsion systems. Both frequency domain and time domain methods have been developed for applications on the turbofan, turbopump, and advanced turboprop. To improve life and performance, the Vibration Control program conceives, analyzes, develops, and demonstrates new methods to control vibrations in aerospace systems. Active and passive vibration control is accomplished with electromagnetic dampers, magnetic bearings, and piezoelectric crystals to control rotor vibrations. The Dynamic Systems program analyzes and verifies the dynamics of interacting systems, as well as develops concepts and methods for high-temperature dynamic seals. The Computational Structural Methods program uses computer science to improve solutions of structural problems.

  6. COLLAGEN STRUCTURE AND STABILITY

    PubMed Central

    Shoulders, Matthew D.; Raines, Ronald T.

    2010-01-01

    Collagen is the most abundant protein in animals. This fibrous, structural protein comprises a right-handed bundle of three parallel, left-handed polyproline II-type helices. Much progress has been made in elucidating the structure of collagen triple helices and the physicochemical basis for their stability. New evidence demonstrates that stereoelectronic effects and preorganization play a key role in that stability. The fibrillar structure of type I collagen–the prototypical collagen fibril–has been revealed in detail. Artificial collagen fibrils that display some properties of natural collagen fibrils are now accessible using chemical synthesis and self-assembly. A rapidly emerging understanding of the mechanical and structural properties of native collagen fibrils will guide further development of artificial collagenous materials for biomedicine and nanotechnology. PMID:19344236

  7. Encapsulation with structured triglycerides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lipids provide excellent materials to encapsulate bioactive compounds for food and pharmaceutical applications. Lipids are renewable, biodegradable, and easily modified to provide additional chemical functionality. The use of structured lipids that have been modified with photoactive properties are ...

  8. The Neutron Structure Function

    NASA Astrophysics Data System (ADS)

    Holt, Roy

    2013-10-01

    Knowledge of the neutron structure function is important for testing models of the nucleon, for a complete understanding of deep inelastic scattering (DIS) from nuclei, and for high energy experiments. As there exist no free neutron targets, neutron structure functions have been determined from deep inelastic scattering from the deuteron. Unfortunately, the short-range part of the deuteron wave function becomes important in extracting the neutron structure function at very high Bjorken x. New methods have been devised for Jefferson Lab experiments to mitigate this problem. The BONUS experiment involves tagging spectator neutrons in the deuteron, while the MARATHON experiment minimizes nuclear structure effects by a comparison of DIS from 3H and 3He. A summary of the status and future plans will be presented. This work supported by the U. S. Department of Energy, Office of Nuclear Physics, under contract DE-AC02-06CH11357.

  9. Vascular structures in dermoscopy*

    PubMed Central

    Ayhan, Erhan; Ucmak, Derya; Akkurt, ZeynepMeltem

    2015-01-01

    Dermoscopy is an aiding method in the visualization of the epidermis and dermis. It is usually used to diagnose melanocytic lesions. In recent years, dermoscopy has increasingly been used to diagnose non-melanocytic lesions. Certain vascular structures, their patterns of arrangement and additional criteria may demonstrate lesion-specific characteristics. In this review, vascular structures and their arrangements are discussed separately in the light of conflicting views and an overview of recent literature. PMID:26375224

  10. Structural control interaction

    NASA Technical Reports Server (NTRS)

    Ryan, R. S.; Mowery, D. K.; Winder, S. W.; Worley, H. E.

    1973-01-01

    The basic guidance and control concepts that lead to structural control interaction and structural dynamic loads are identified. Space vehicle ascent flight load sources and the load relieving mechanism are discussed, along with the the characteristics and special problems of both present and future space vehicles including launch vehicles, orbiting vehicles, and the Space Shuttle flyback vehicle. The special dynamics and control analyses and test problems apparent at this time are summarized.

  11. Structured luminescence conversion layer

    DOEpatents

    Berben, Dirk; Antoniadis, Homer; Jermann, Frank; Krummacher, Benjamin Claus; Von Malm, Norwin; Zachau, Martin

    2012-12-11

    An apparatus device such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer deposited on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains regions such as color-changing and non-color-changing regions with particular shapes arranged in a particular pattern.

  12. Physics of structural colors

    NASA Astrophysics Data System (ADS)

    Kinoshita, S.; Yoshioka, S.; Miyazaki, J.

    2008-07-01

    In recent years, structural colors have attracted great attention in a wide variety of research fields. This is because they are originated from complex interaction between light and sophisticated nanostructures generated in the natural world. In addition, their inherent regular structures are one of the most conspicuous examples of non-equilibrium order formation. Structural colors are deeply connected with recent rapidly growing fields of photonics and have been extensively studied to clarify their peculiar optical phenomena. Their mechanisms are, in principle, of a purely physical origin, which differs considerably from the ordinary coloration mechanisms such as in pigments, dyes and metals, where the colors are produced by virtue of the energy consumption of light. It is generally recognized that structural colors are mainly based on several elementary optical processes including thin-layer interference, diffraction grating, light scattering, photonic crystals and so on. However, in nature, these processes are somehow mixed together to produce complex optical phenomena. In many cases, they are combined with the irregularity of the structure to produce the diffusive nature of the reflected light, while in some cases they are accompanied by large-scale structures to generate the macroscopic effect on the coloration. Further, it is well known that structural colors cooperate with pigmentary colors to enhance or to reduce the brilliancy and to produce special effects. Thus, structure-based optical phenomena in nature appear to be quite multi-functional, the variety of which is far beyond our understanding. In this article, we overview these phenomena appearing particularly in the diversity of the animal world, to shed light on this rapidly developing research field.

  13. Integrated support structure

    NASA Technical Reports Server (NTRS)

    Bruneau, Stephen D.; Campbell, John T.; Struven, Christopher A.

    1990-01-01

    This Major Qualifying Project is part of the Advanced Space Design Program at WPI. The goal is to design a support structure for a NASA GetAway Special experimental canister. The payload integration, weight, volume, and structural integrity of the canister as specified by NASA guidelines were studied. The end result is a complete set of design drawings with interface drawings and data to specify the design and leave a base on which the next group can concentrate.

  14. Singularity in structural optimization

    NASA Technical Reports Server (NTRS)

    Patnaik, S. N.; Guptill, J. D.; Berke, L.

    1993-01-01

    The conditions under which global and local singularities may arise in structural optimization are examined. Examples of these singularities are presented, and a framework is given within which the singularities can be recognized. It is shown, in particular, that singularities can be identified through the analysis of stress-displacement relations together with compatibility conditions or the displacement-stress relations derived by the integrated force method of structural analysis. Methods of eliminating the effects of singularities are suggested and illustrated numerically.

  15. REACTOR MODERATOR STRUCTURE

    DOEpatents

    Greenstreet, B.L.

    1963-12-31

    A system for maintaining the alignment of moderator block structures in reactors is presented. Integral restraining grids are placed between each layer of blocks in the moderator structure, at the top of the uppermost layer, and at the bottom of the lowermost layer. Slots are provided in the top and bottom surfaces of the moderator blocks so as to provide a keying action with the grids. The grids are maintained in alignment by vertical guiding members disposed about their peripheries. (AEC)

  16. Structure function monitor

    SciTech Connect

    McGraw, John T.; Zimmer, Peter C.; Ackermann, Mark R.

    2012-01-24

    Methods and apparatus for a structure function monitor provide for generation of parameters characterizing a refractive medium. In an embodiment, a structure function monitor acquires images of a pupil plane and an image plane and, from these images, retrieves the phase over an aperture, unwraps the retrieved phase, and analyzes the unwrapped retrieved phase. In an embodiment, analysis yields atmospheric parameters measured at spatial scales from zero to the diameter of a telescope used to collect light from a source.

  17. Adaptive Structures Flight Experiments

    NASA Technical Reports Server (NTRS)

    Martin, Maurice

    1992-01-01

    The topics are presented in viewgraph form and include the following: adaptive structures flight experiments; enhanced resolution using active vibration suppression; Advanced Controls Technology Experiment (ACTEX); ACTEX program status; ACTEX-2; ACTEX-2 program status; modular control patch; STRV-1b Cryocooler Vibration Suppression Experiment; STRV-1b program status; Precision Optical Bench Experiment (PROBE); Clementine Spacecraft Configuration; TECHSAT all-composite spacecraft; Inexpensive Structures and Materials Flight Experiment (INFLEX); and INFLEX program status.

  18. Adaptive structures flight experiments

    NASA Astrophysics Data System (ADS)

    Martin, Maurice

    The topics are presented in viewgraph form and include the following: adaptive structures flight experiments; enhanced resolution using active vibration suppression; Advanced Controls Technology Experiment (ACTEX); ACTEX program status; ACTEX-2; ACTEX-2 program status; modular control patch; STRV-1b Cryocooler Vibration Suppression Experiment; STRV-1b program status; Precision Optical Bench Experiment (PROBE); Clementine Spacecraft Configuration; TECHSAT all-composite spacecraft; Inexpensive Structures and Materials Flight Experiment (INFLEX); and INFLEX program status.

  19. Structural traps 5

    SciTech Connect

    Foster, N.H.; Beaumont, E.A.

    1991-01-01

    This book contains studies of oil and gas fields that are mainly structural in nature. Stratigraphy controls the extend of the reservoir in the traps of several fields, but overall, the main trapping features within the group of fields in this volume are structural. Fields covered in this volume include: Endicott Field, Point Arguello Field, West Puerto Chiquito Field, Dukhan Field, Sendji Field, Ruston Field, Raudhatain Field, Hassi Messaoud Field, Snapper Field, Tirrawarra Field, and Sacha Field.

  20. Integral Textile Ceramic Structures

    NASA Astrophysics Data System (ADS)

    Marshall, David B.; Cox, Brian N.

    2008-08-01

    A new paradigm for ceramic composite structural components enables functionality in heat exchange, transpiration, detailed shape, and thermal strain management that significantly exceeds the prior art. The paradigm is based on the use of three-dimensional fiber reinforcement that is tailored to the specific shape, stress, and thermal requirements of a structural application and therefore generally requires innovative textile methods for each realization. Key features include the attainment of thin skins (less than 1 mm) that are nevertheless structurally robust, transpiration holes formed without cutting fibers, double curvature, compliant integral attachment to other structures that avoids thermal stress buildup, and microcomposite ceramic matrices that minimize spalling and allow the formation of smooth surfaces. All these features can be combined into structures of very varied gross shape and function, using a wide range of materials such as all-oxide systems and SiC and carbon fibers in SiC matrices. Illustrations are drawn from rocket nozzles, thermal protection systems, and gas turbine engines. The new design challenges that arise for such material/structure systems are being met by specialized computational modeling that departs significantly in the representation of materials behavior from that used in conventional finite element methods.

  1. Structural analysis of glucans

    PubMed Central

    Novak, Miroslav

    2014-01-01

    Glucans are most widespread polysaccharides in the nature. There is a large diversity in their molecular weight and configuration depending on the original source. According to the anomeric structure of glucose units it is possible to distinguish linear and branched α-, β- as well as mixed α,β-glucans with various glycoside bond positions and molecular masses. Isolation of glucans from raw sources needs removal of ballast compounds including proteins, lipids, polyphenols and other polysaccharides. Purity control of glucan fractions is necessary to evaluate the isolation and purification steps; more rigorous structural analyses of purified polysaccharides are required to clarify their structure. A set of spectroscopic, chemical and separation methods are used for this purpose. Among them, NMR spectroscopy is known as a powerful tool in structural analysis of glucans both in solution and in solid state. Along with chemolytic methods [methylation analysis (MA), periodate oxidation, partial chemical or enzymatic hydrolysis, etc.], correlation NMR experiments are able to determine the exact structure of tested polysaccharides. Vibration spectroscopic methods (FTIR, Raman) are sensitive to anomeric structure of glucans and can be used for purity control as well. Molecular weight distribution, homogeneity and branching of glucans can be estimated by size-exclusion chromatography (SEC), laser light scattering (LLS) and viscometry. PMID:25332993

  2. RNA Thermodynamic Structural Entropy

    PubMed Central

    Garcia-Martin, Juan Antonio; Clote, Peter

    2015-01-01

    Conformational entropy for atomic-level, three dimensional biomolecules is known experimentally to play an important role in protein-ligand discrimination, yet reliable computation of entropy remains a difficult problem. Here we describe the first two accurate and efficient algorithms to compute the conformational entropy for RNA secondary structures, with respect to the Turner energy model, where free energy parameters are determined from UV absorption experiments. An algorithm to compute the derivational entropy for RNA secondary structures had previously been introduced, using stochastic context free grammars (SCFGs). However, the numerical value of derivational entropy depends heavily on the chosen context free grammar and on the training set used to estimate rule probabilities. Using data from the Rfam database, we determine that both of our thermodynamic methods, which agree in numerical value, are substantially faster than the SCFG method. Thermodynamic structural entropy is much smaller than derivational entropy, and the correlation between length-normalized thermodynamic entropy and derivational entropy is moderately weak to poor. In applications, we plot the structural entropy as a function of temperature for known thermoswitches, such as the repression of heat shock gene expression (ROSE) element, we determine that the correlation between hammerhead ribozyme cleavage activity and total free energy is improved by including an additional free energy term arising from conformational entropy, and we plot the structural entropy of windows of the HIV-1 genome. Our software RNAentropy can compute structural entropy for any user-specified temperature, and supports both the Turner’99 and Turner’04 energy parameters. It follows that RNAentropy is state-of-the-art software to compute RNA secondary structure conformational entropy. Source code is available at https://github.com/clotelab/RNAentropy/; a full web server is available at http

  3. GENERAL VIEW OF DEHYDRATER (STRUCTURE 12), SHED (STRUCTURE 18), FRUIT ...

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

    GENERAL VIEW OF DEHYDRATER (STRUCTURE 12), SHED (STRUCTURE 18), FRUIT TRAY STORAGE ROOM (STRUCTURE 11), WITH FRUIT DRYING AREA AND TRAM TRACKS IN FOREGROUND, FROM NORTHWEST - Stevens Ranch Complex, State Route 101, Coyote, Santa Clara County, CA

  4. The Quality and Validation of Structures from Structural Genomics

    PubMed Central

    Domagalski, Marcin J.; Zheng, Heping; Zimmerman, Matthew D.; Dauter, Zbigniew; Wlodawer, Alexander; Minor, Wladek

    2014-01-01

    Quality control of three-dimensional structures of macromolecules is a critical step to ensure the integrity of structural biology data, especially those produced by structural genomics centers. Whereas the Protein Data Bank (PDB) has proven to be a remarkable success overall, the inconsistent quality of structures reveals a lack of universal standards for structure/deposit validation. Here, we review the state-of-the-art methods used in macromolecular structure validation, focusing on validation of structures determined by X-ray crystallography. We describe some general protocols used in the rebuilding and re-refinement of problematic structural models. We also briefly discuss some frontier areas of structure validation, including refinement of protein–ligand complexes, automation of structure redetermination, and the use of NMR structures and computational models to solve X-ray crystal structures by molecular replacement. PMID:24203341

  5. Controls for space structures

    NASA Technical Reports Server (NTRS)

    Balas, Mark

    1991-01-01

    Assembly and operation of large space structures (LSS) in orbit will require robot-assisted docking and berthing of partially-assembled structures. These operations require new solutions to the problems of controls. This is true because of large transient and persistent disturbances, controller-structure interaction with unmodeled modes, poorly known structure parameters, slow actuator/sensor dynamical behavior, and excitation of nonlinear structure vibrations during control and assembly. For on-orbit assembly, controllers must start with finite element models of LSS and adapt on line to the best operating points, without compromising stability. This is not easy to do, since there are often unmodeled dynamic interactions between the controller and the structure. The indirect adaptive controllers are based on parameter estimation. Due to the large number of modes in LSS, this approach leads to very high-order control schemes with consequent poor stability and performance. In contrast, direct model reference adaptive controllers operate to force the LSS to track the desirable behavior of a chosen model. These schemes produce simple control algorithms which are easy to implement on line. One problem with their use for LSS has been that the model must be the same dimension as the LSS - i.e., quite large. A control theory based on the command generator tracker (CGT) ideas of Sobel, Mabins, Kaufman and Wen, Balas to obtain very low-order models based on adaptive algorithms was developed. Closed-loop stability for both finite element models and distributed parameter models of LSS was proved. In addition, successful numerical simulations on several LSS databases were obtained. An adaptive controller based on our theory was also implemented on a flexible robotic manipulator at Martin Marietta Astronautics. Computation schemes for controller-structure interaction with unmodeled modes, the residual mode filters or RMF, were developed. The RMF theory was modified to compensate

  6. Carbon Structure Hazard Control

    NASA Technical Reports Server (NTRS)

    Yoder, Tommy; Greene, Ben; Porter, Alan

    2015-01-01

    Carbon composite structures are widely used in virtually all advanced technology industries for a multitude of applications. The high strength-to-weight ratio and resistance to aggressive service environments make them highly desirable. Automotive, aerospace, and petroleum industries extensively use, and will continue to use, this enabling technology. As a result of this broad range of use, field and test personnel are increasingly exposed to hazards associated with these structures. No single published document exists to address the hazards and make recommendations for the hazard controls required for the different exposure possibilities from damaged structures including airborne fibers, fly, and dust. The potential for personnel exposure varies depending on the application or manipulation of the structure. The effect of exposure to carbon hazards is not limited to personnel, protection of electronics and mechanical equipment must be considered as well. The various exposure opportunities defined in this document include pre-manufacturing fly and dust, the cured structure, manufacturing/machining, post-event cleanup, and post-event test and/or evaluation. Hazard control is defined as it is applicable or applied for the specific exposure opportunity. The carbon exposure hazard includes fly, dust, fiber (cured/uncured), and matrix vapor/thermal decomposition products. By using the recommendations in this document, a high level of confidence can be assured for the protection of personnel and equipment.

  7. Determining structural performance

    NASA Technical Reports Server (NTRS)

    Ernst, Michael A. (Editor); Brown, Gerald; Dirusso, Eliseo; Fleming, David; Janetzke, David; Kascak, Albert; Kaza, Krishna; Kielb, Robert; Kiraly, Louis J.; Lawrence, Charles

    1990-01-01

    An overview of the methods and concepts developed to enhance and predict structural dynamic characteristics of advanced aeropropulsion systems is presented. Aeroelasticity, vibration control, dynamic systems, and computational structural methods are four disciplines that make up the structural dynamic effort at LeRC. The aeroelasticity program develops analytical and experimental methods for minimizing flutter and forced vibration of aerospace propulsion systems. Both frequency domain and time domain methods were developed for applications on the turbofan, turbopump, and advanced turboprop. In order to improve life and performance, the vibration control program conceives, analyzes, develops, and demonstrates new methods for controlling vibrations in aerospace systems. Active and passive vibration control is accomplished with electromagnetic dampers, magnetic bearings, and piezoelectric crystals to control rotor vibrations. The dynamic systems program analyzes and verifies the dynamics of interacting systems, as well as develops concepts and methods for high-temperature dynamic seals. Work in this field involves the analysis and parametric identification of large, nonlinear, damped, stochastic systems. The computational structural methods program exploits modern computer science as an aid to the solutions of structural problems.

  8. PRSEUS Structural Concept Development

    NASA Technical Reports Server (NTRS)

    Velicki, Alex; Jegley, Dawn

    2014-01-01

    A lighter, more robust airframe is one of the key technological advancements necessary for the successful launch of any large next-generation transport aircraft. Such a premise dictates that considerable improvements beyond current state-of-the-art aluminum structures is needed, and that improvements of this magnitude will require an extensive use of composite materials that are not only lightweight, but also economical to produce. To address this challenge, researchers at NASA and The Boeing Company are developing a novel structural concept called the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) under the Environmentally Responsible Aviation (ERA) Project. It is an integrally stiffened panel concept that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. In addition to improved structural performance, an important facet of this unique arrangement of stitched carbon fibers is its innovative manufacturing method that has the potential to lower fabrication costs by eliminating fasteners and autoclave cures. The rationale and development status for this new approach forms the basis of the work described in this paper. The test specimens described herein were fabricated, or are currently being fabricated, by The Boeing Company, while the structural analyses and testing tasks are being performed by NASA and Boeing personnel.

  9. FRP : Strengthened RC Structures

    NASA Astrophysics Data System (ADS)

    Teng, J. G.; Chen, J. F.; Smith, S. T.; Lam, L.

    2002-01-01

    The strengthening of reinforced concrete (RC) structures using advanced fibre-reinforced polymer (FRP) composites, and in particular the behaviour of FRP-strengthened RC structures is a topic which has become very popular in recent years. This popularity has arisen due to the need to maintain and upgrade essential infrastructure in all parts of the world, combined with the well-known advantages of FRP composites, such as good corrosion resistance and ease for site handling due to their light weight. The continuous reduction in the material cost of FRP composites has also contributed to their popularity. While a great amount of research now exists in the published literature on this topic, it is scattered in various journals and conference proceedings. This book therefore provides the first ever comprehensive, state-of-the-art summary of the existing research on FRP strengthening of RC structures, with the emphasis being on structural behaviour and strength models. The main topics covered include: Bond behaviour Flexural and shear strengthening of beams Column strengthening Flexural strengthening of slabs. For each area, the methods of strengthening are discussed, followed by a description of behaviour and failure modes and then the presentation of rational design recommendations, for direct use in practical design of FRP strengthening measures. Researchers, practicing engineers, code writers and postgraduate students in structural engineering and construction materials, as well as consulting firms, government departments, professional bodies, contracting firms and FRP material suppliers will find this an invaluable resource.

  10. Expert Cold Structure Development

    NASA Astrophysics Data System (ADS)

    Atkins, T.; Demuysere, P.

    2011-05-01

    The EXPERT Program is funded by ESA. The objective of the EXPERT mission is to perform a sub-orbital flight during which measurements of critical aero- thermodynamic phenomena will be obtained by using state-of-the-art instrumentation. As part of the EXPERT Flight Segment, the responsibility of the Cold Structure Development Design, Manufacturing and Validation was committed to the Belgian industrial team SONACA/SABCA. The EXPERT Cold Structure includes the Launcher Adapter, the Bottom Panel, the Upper Panel, two Cross Panels and the Parachute Bay. An additional Launcher Adapter was manufactured for the separation tests. The selected assembly definition and manufacturing technologies ( machined parts and sandwich panels) were dictated classically by the mass and stiffness, but also by the CoG location and the sensitive separation interface. Used as support for the various on-board equipment, the Cold Structure is fixed to but thermally uncoupled from the PM 1000 thermal shield. It is protect on its bottom panel by a thermal blanket. As it is a protoflight, analysis was the main tool for the verification. Low level stiffness and modal analysis tests have also been performed on the Cold Structure equipped with its ballast. It allowed to complete its qualification and to prepare SONACA/SABCA support for the system dynamic tests foreseen in 2011. The structure was finally coated with a thermal control black painting and delivered on time to Thales Alenia Space-Italy end of March 201.

  11. Structural graphitic carbon foams

    SciTech Connect

    Kearns, K.M.; Anderson, H.J.

    1998-12-31

    Graphitic carbon foams are a unique material form with very high structural and thermal properties at a light weight. A process has been developed to produce microcellular, open-celled graphitic foams. The process includes heating a mesophase pitch preform above the pitch melting temperature in a pressurized reactor. At the appropriate time, the pressure is released, the gas nucleates bubbles, and these bubbles grow forming the pitch into the foam structure. The resultant foamed pitch is then stabilized in an oxygen environment. At this point a rigid structure exists with some mechanical integrity. The foam is then carbonized to 800 C followed by a graphitization to 2700 C. The shear action from the growing bubbles aligns the graphitic planes along the foam struts to provide the ideal structure for good mechanical properties. Some of these properties have been characterized for some of the foam materials. It is known that variations of the blowing temperature, blowing pressure and saturation time result in foams of variously sized with mostly open pores; however, the mechanism of bubble nucleation is not known. Therefore foams were blown with various gases to begin to determine the nucleation method. These gases are comprised of a variety of molecular weights as well as a range of various solubility levels. By examining the resultant structures of the foam, differences were noted to develop an explanation of the foaming mechanism.

  12. Solar efficient structure

    SciTech Connect

    Arenas, F.B.

    1985-02-12

    A solar efficient structure is disclosed which comprises a central chase positioned vertically within the structure and connected in fluid communication with a duct network positioned in thermal contact with the ground and with the attic of the structure. A fan is provided for circulating air through a perforated attic duct, through the various rooms of the structure, and through the duct network and the chase. In one embodiment, the fan is reversible so as to circulate the air in one direction, or in the other direction. When operating in the heating mode, the ground acts as a heat source to heat the air circulating through the duct network. Conversely, when operating in the cooling mode, the ground acts as a heat sink to cool the airflow circulating therethrough. A dehumidifier, and a heating or cooling means is provided for assisting in the conditioning of the circulating airflow. In one embodiment, the heating means comprises a greenhouse room which permits ultraviolet radiation to enter and heat the air contained therein, and a damper means for controlling the flow rate of the air circulating through the greenhouse room. The structure is fully insulated and includes a vent skin positioned about the exterior walls and the roof thereof. A method is disclosed for insulating the roof line with loose insulation.

  13. Prosodic Structure as a Parallel to Musical Structure.

    PubMed

    Heffner, Christopher C; Slevc, L Robert

    2015-01-01

    What structural properties do language and music share? Although early speculation identified a wide variety of possibilities, the literature has largely focused on the parallels between musical structure and syntactic structure. Here, we argue that parallels between musical structure and prosodic structure deserve more attention. We review the evidence for a link between musical and prosodic structure and find it to be strong. In fact, certain elements of prosodic structure may provide a parsimonious comparison with musical structure without sacrificing empirical findings related to the parallels between language and music. We then develop several predictions related to such a hypothesis. PMID:26733930

  14. Prosodic Structure as a Parallel to Musical Structure

    PubMed Central

    Heffner, Christopher C.; Slevc, L. Robert

    2015-01-01

    What structural properties do language and music share? Although early speculation identified a wide variety of possibilities, the literature has largely focused on the parallels between musical structure and syntactic structure. Here, we argue that parallels between musical structure and prosodic structure deserve more attention. We review the evidence for a link between musical and prosodic structure and find it to be strong. In fact, certain elements of prosodic structure may provide a parsimonious comparison with musical structure without sacrificing empirical findings related to the parallels between language and music. We then develop several predictions related to such a hypothesis. PMID:26733930

  15. Diagnostics and structure

    NASA Technical Reports Server (NTRS)

    Vial, J. C.

    1986-01-01

    The structure of prominences and the diagnostic techniques used to evaluate their physical parameters are discussed. These include electron temperature, various densities (n sub p, n sub e, n sub l), ionization degree, velocities, and magnetic field vector. UV and radio measurements have already evidenced the existence of different temperature regions, corresponding to different geometrical locations, e.g., the so called Prominence-Corona (P-C) interface. Velocity measurements are important for considering formation and mass balance of prominences but there are conflicting velocity measurements which have led to the basic question: what structure is actually observed at a given wavelength; what averaging is performed within the projected slit area during the exposure time? In optically thick lines, the question of the formation region of the radiation along the line of sight is also not a trivial one. The same is true for low resolution measurements of the magnetic field. Coupling diagnostics with structure is now a general preoccupation.

  16. Structural power flow measurement

    SciTech Connect

    Falter, K.J.; Keltie, R.F.

    1988-12-01

    Previous investigations of structural power flow through beam-like structures resulted in some unexplained anomalies in the calculated data. In order to develop structural power flow measurement as a viable technique for machine tool design, the causes of these anomalies needed to be found. Once found, techniques for eliminating the errors could be developed. Error sources were found in the experimental apparatus itself as well as in the instrumentation. Although flexural waves are the carriers of power in the experimental apparatus, at some frequencies longitudinal waves were excited which were picked up by the accelerometers and altered power measurements. Errors were found in the phase and gain response of the sensors and amplifiers used for measurement. A transfer function correction technique was employed to compensate for these instrumentation errors.

  17. Computational engine structural analysis

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Johns, R. H.

    1986-01-01

    A significant research activity at the NASA Lewis Research Center is the computational simulation of complex multidisciplinary engine structural problems. This simulation is performed using computational engine structural analysis (CESA) which consists of integrated multidisciplinary computer codes in conjunction with computer post-processing for problem-specific application. A variety of the computational simulations of specific cases are described in some detail in this paper. These case studies include: (1) aeroelastic behavior of bladed rotors, (2) high velocity impact of fan blades, (3) blade-loss transient response, (4) rotor/stator/squeeze-film/bearing interaction, (5) blade-fragment/rotor-burst containment, and (6) structural behavior of advanced swept turboprops. These representative case studies are selected to demonstrate the breath of the problems analyzed and the role of the computer including post-processing and graphical display of voluminous output data.

  18. Magnetosheath Filamentary Structures

    NASA Astrophysics Data System (ADS)

    Rojas-Castillo, D. I.; Blanco-Cano, X.; Omidi, N.; Kajdic, P.

    2014-12-01

    The terrestrial magnetosheath is full of highly perturbed plasma. The inhomogeneity of this region leads to temperature anisotropies that can originate waves; e.g, mirror mode and ion cyclotron waves. Other structures like the magnetosheath filamentary structures (MFS) can also be present. These are structures reported from results of global hybrid simulations by Omidi et al. (2014) that are formed in the quasi-parallel region of the bow shock and they are convected into the magnetosheath. The MFS are characterized by field aligned enhancements of density and temperature that are anti-correlated. In this work we analyze magnetic field and plasma data from the THEMIS mission to explore the possible existence of MFS.

  19. Structural Equation Model Trees

    PubMed Central

    Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

    2015-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree structures that separate a data set recursively into subsets with significantly different parameter estimates in a SEM. SEM Trees provide means for finding covariates and covariate interactions that predict differences in structural parameters in observed as well as in latent space and facilitate theory-guided exploration of empirical data. We describe the methodology, discuss theoretical and practical implications, and demonstrate applications to a factor model and a linear growth curve model. PMID:22984789

  20. The Structure Lacuna

    PubMed Central

    Boeyens, Jan C.A.; Levendis, Demetrius C.

    2012-01-01

    Molecular symmetry is intimately connected with the classical concept of three-dimensional molecular structure. In a non-classical theory of wave-like interaction in four-dimensional space-time, both of these concepts and traditional quantum mechanics lose their operational meaning, unless suitably modified. A required reformulation should emphasize the importance of four-dimensional effects like spin and the symmetry effects of space-time curvature that could lead to a fundamentally different understanding of molecular symmetry and structure in terms of elementary number theory. Isolated single molecules have no characteristic shape and macro-biomolecules only develop robust three-dimensional structure in hydrophobic response to aqueous cellular media. PMID:22942753

  1. Observed Quasar Structure

    NASA Astrophysics Data System (ADS)

    Schild, Rudolph E.

    2011-05-01

    With the introduction of microlensing (nano-lensing) and reverberation analysis, understanding of the luminous structure surrounding quasars has gone from theoretical speculation to an observer's sport. Micro-lensing with day timescale has demonstrated that quasars have structure on scales of 1 R_G which we attribute to the inner edge of the accretion disc, at central distance 70 R_G in lo-hard state (radio loud) Q0957 quasar, indicated by reverberation. Reverberation of the dominant optical continuum has been detected in all 55 hi-soft quasars with brightness data, originating in the dusty torus observed in UV-optical and IR reverberation. Microlensing simulation compared to brightness monitoring shows that 2/3 of the UV-optical continuum originates in the outer torus. The observed color effects observed in the microlensing support the existence of inner and outer luminous structure.

  2. Rethinking cell structure.

    PubMed Central

    Penman, S

    1995-01-01

    Cell structure, emerging from behind the veil of conventional electron microscopy, appears far more complex than formerly realized. The standard plastic-embedded, ultrathin section can image only what is on the section surface and masks the elaborate networks of the cytoplasm and nucleus. Embedment-free electron microscopy gives clear, high-contrast micrographs of cell structure when combined with removal of obscuring material such as soluble proteins. The resinless ultrathin section is the technique of choice; it is simple and inexpensive, and it uses ordinary electron microscopes. The resulting pictures reveal a world of complex cell structure and function. These images necessarily change our conception of the cytoskeleton, nuclear matrix, mitosis, and the relation of membranes to cytostructure. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:7777493

  3. Structural Acoustics and Vibrations

    NASA Astrophysics Data System (ADS)

    Chaigne, Antoine

    This structural chapter is devoted to vibrations of structures and to their coupling with the acoustic field. Depending on the context, the radiated sound can be judged as desirable, as is mostly the case for musical instruments, or undesirable, like noise generated by machinery. In architectural acoustics, one main goal is to limit the transmission of sound through walls. In the automobile industry, the engineers have to control the noise generated inside and outside the passenger compartment. This can be achieved by means of passive or active damping. In general, there is a strong need for quieter products and better sound quality generated by the structures in our daily environment.

  4. Tendon Structure and Composition.

    PubMed

    Thorpe, Chavaunne T; Screen, Hazel R C

    2016-01-01

    Tendons are soft, fibrous tissues that connect muscle to bone. Their main function is to transfer muscle generated force to the bony skeleton, facilitating movement around a joint, and as such they are relatively passive, inelastic structures, able to resist high forces. Tendons are predominantly composed of collagen, which is arranged in a hierarchical manner parallel to the long axis of the tendon, resulting in high tensile strength. Tendon also contains a range of non-collagenous proteins, present in low amounts, which nevertheless have important functional roles. In this chapter, we describe general tendon composition and structure, and discuss how variations in composition and structure at different levels of the tendon hierarchy confer specific mechanical properties, which are related to tendon function. PMID:27535244

  5. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1981-01-01

    The composite aircraft program component (CAPCOMP) is a graduate level project conducted in parallel with a composite structures program. The composite aircraft program glider (CAPGLIDE) is an undergraduate demonstration project which has as its objectives the design, fabrication, and testing of a foot launched ultralight glider using composite structures. The objective of the computer aided design (COMPAD) portion of the composites project is to provide computer tools for the analysis and design of composite structures. The major thrust of COMPAD is in the finite element area with effort directed at implementing finite element analysis capabilities and developing interactive graphics preprocessing and postprocessing capabilities. The criteria for selecting research projects to be conducted under the innovative and supporting research (INSURE) program are described.

  6. Modular arctic structures system

    SciTech Connect

    Reusswig, G. H.

    1984-12-04

    A modular and floatable offshore exploration and production platform system for use in shallow arctic waters is disclosed. A concrete base member is floated to the exploration or production site, and ballated into a predredged cavity. The cavity and base are sized to provide a stable horizontal base 30 feet below the mean water/ice plane. An exploration or production platform having a massive steel base is floated to the site and ballasted into position on the base. Together, the platform, base and ballast provide a massive gravity structure that is capable of resisting large ice and wave forces that impinge on the structure. The steel platform has a sloping hourglass profile to deflect horizontal ice loads vertically, and convert the horizontal load to a vertical tensile stress, which assists in breaking the ice as it advances toward the structure.

  7. Underground waste barrier structure

    DOEpatents

    Saha, Anuj J.; Grant, David C.

    1988-01-01

    Disclosed is an underground waste barrier structure that consists of waste material, a first container formed of activated carbonaceous material enclosing the waste material, a second container formed of zeolite enclosing the first container, and clay covering the second container. The underground waste barrier structure is constructed by forming a recessed area within the earth, lining the recessed area with a layer of clay, lining the clay with a layer of zeolite, lining the zeolite with a layer of activated carbonaceous material, placing the waste material within the lined recessed area, forming a ceiling over the waste material of a layer of activated carbonaceous material, a layer of zeolite, and a layer of clay, the layers in the ceiling cojoining with the respective layers forming the walls of the structure, and finally, covering the ceiling with earth.

  8. Superalloy Lattice Block Structures

    NASA Technical Reports Server (NTRS)

    Nathal, M. V.; Whittenberger, J. D.; Hebsur, M. G.; Kantzos, P. T.; Krause, D. L.

    2004-01-01

    Initial investigations of investment cast superalloy lattice block suggest that this technology will yield a low cost approach to utilize the high temperature strength and environmental resistance of superalloys in lightweight, damage tolerant structural configurations. Work to date has demonstrated that relatively large superalloy lattice block panels can be successfully investment cast from both IN-718 and Mar-M247. These castings exhibited mechanical properties consistent with the strength of the same superalloys measured from more conventional castings. The lattice block structure also accommodates significant deformation without failure, and is defect tolerant in fatigue. The potential of lattice block structures opens new opportunities for the use of superalloys in future generations of aircraft applications that demand strength and environmental resistance at elevated temperatures along with low weight.

  9. Structures behind superconductivity

    SciTech Connect

    Rotman, D.

    1988-07-01

    The previously reported preparation and structures of superconducting materials are reviewed. The two systems, Y-Ba-Cu-O and La-Cu-O, previously reported with high transition temperatures are discussed in some detail. The new systems introduced in 1987 that were not based on a rare earth but including Bi-Sr-Cu-O are also reviewed. Superconductive materials including thallium rather than bismuth that have been reported but not thoroughly studied are discussed briefly. It is pointed out that many superconducting materials have been prepared, but good documentation of the structures and properties of these materials need much more study.

  10. Aerospace structures supportability

    NASA Astrophysics Data System (ADS)

    Smith, Howard Wesley

    1989-04-01

    This paper is about supportability in its general sense, with emphasis on aerospace structures. Reliability and maintainability (R&M) are described and defined from the standpoint of both structural analysis. Accessability, inspectability, and replaceability are described as design attributes. Reliability and probability of failure are shown to be in the domain of the analysis. Availability and replaceability are traditional logistic responsibilities which are influenced by supportability engineers. The USAF R&M 2000 process is described, and the R&M 1988 Workshop at Wright-Patterson Air Force Base is also included in the description.

  11. Microemulsions: Structure and dynamics

    SciTech Connect

    Friberg, S.E.; Bothorel, P.

    1987-01-01

    This book covers the state-of-the-art in stability, structure, applications, and dynamics representation of microemulsion systems. An international group of reviewers discuss the introductory investigations into macroemulsions and interfacial free energy, the derivation of the microemulsion systems from micellar solutions, and the correlation between structure and dynamics. Future developments in this area are also considered. The book presents following: contents; phase diagrams and pseudophase assumption; phase diagram and critical behavior of a quaternary microemulsion system; non-aqueous microemulsions; nonionics; molecular diffusion in microemulsions; dynamics of microemulsions; low interfacial tensions in microemulsion systems; oil recovery and microemulsions.

  12. Stellar structure of magnetars

    NASA Astrophysics Data System (ADS)

    Dong, JianMin; Zuo, Wei; Gu, JianZhong; Shang, XinLe

    2016-04-01

    Magnetars are strong magnetized neutron stars which could emit quiescent X-ray, repeating burst of soft gamma ray, and even the giant flares. We investigate the effects of magnetic fields on the structure of isolated magnetars. The stellar structure together with the magnetic field configuration can be obtained at the same time within a self-consistent procedure. The magnetar mass and radius are found to be weakly enhanced by the strong magnetic fields. Unlike other previous investigations, the magnetic field is unable to violate the mass limit of the neutron stars.

  13. Objective Eulerian coherent structures.

    PubMed

    Serra, Mattia; Haller, George

    2016-05-01

    We define objective Eulerian Coherent Structures (OECSs) in two-dimensional, non-autonomous dynamical systems as the instantaneously most influential material curves. Specifically, OECSs are stationary curves of the averaged instantaneous material stretching-rate or material shearing-rate functionals. From these objective (frame-invariant) variational principles, we obtain explicit differential equations for hyperbolic, elliptic, and parabolic OECSs. As an illustration, we compute OECSs in an unsteady ocean velocity data set. In comparison to structures suggested by other common Eulerian diagnostic tools, we find OECSs to be the correct short-term cores of observed trajectory deformation patterns. PMID:27249950

  14. Structural Acoustics and Vibrations

    NASA Astrophysics Data System (ADS)

    Chaigne, Antoine

    This chapter is devoted to vibrations of structures and to their coupling with the acoustic field. Depending on the context, the radiated sound can be judged as desirable, as is mostly the case for musical instruments, or undesirable, like noise generated by machinery. In architectural acoustics, one main goal is to limit the transmission of sound through walls. In the automobile industry, the engineers have to control the noise generated inside and outside the passenger compartment. This can be achieved by means of passive or active damping. In general, there is a strong need for quieter products and better sound quality generated by the structures in our daily environment.

  15. Multiscale structure of meanders

    NASA Astrophysics Data System (ADS)

    Vermeulen, B.; Hoitink, A. J. F.; Zolezzi, G.; Abad, J. D.; Aalto, R.

    2016-04-01

    River meander planforms can be described based on wavelet analysis, but an objective method to identify the main characteristics of a meander planform over all spatial scales is yet to be found. Here we show how a set of simple metrics representing meander shape can be retrieved from a continuous wavelet transform of a planform geometry. We construct a synoptic multiple looping tree to establish the meander structure, revealing the embedding of dominant meander scales in larger-scale loops. The method can be applied beyond the case of rivers to unravel the meandering structure of lava flows, turbidity currents, tidal channels, rivulets, supraglacial streams, and extraterrestrial flows.

  16. Objective Eulerian coherent structures

    NASA Astrophysics Data System (ADS)

    Serra, Mattia; Haller, George

    2016-05-01

    We define objective Eulerian Coherent Structures (OECSs) in two-dimensional, non-autonomous dynamical systems as the instantaneously most influential material curves. Specifically, OECSs are stationary curves of the averaged instantaneous material stretching-rate or material shearing-rate functionals. From these objective (frame-invariant) variational principles, we obtain explicit differential equations for hyperbolic, elliptic, and parabolic OECSs. As an illustration, we compute OECSs in an unsteady ocean velocity data set. In comparison to structures suggested by other common Eulerian diagnostic tools, we find OECSs to be the correct short-term cores of observed trajectory deformation patterns.

  17. Structural mechanics simulations

    NASA Technical Reports Server (NTRS)

    Biffle, Johnny H.

    1992-01-01

    Sandia National Laboratory has a very broad structural capability. Work has been performed in support of reentry vehicles, nuclear reactor safety, weapons systems and components, nuclear waste transport, strategic petroleum reserve, nuclear waste storage, wind and solar energy, drilling technology, and submarine programs. The analysis environment contains both commercial and internally developed software. Included are mesh generation capabilities, structural simulation codes, and visual codes for examining simulation results. To effectively simulate a wide variety of physical phenomena, a large number of constitutive models have been developed.

  18. Structure of spinel

    SciTech Connect

    Sickafus, K.E.; Wills, J.M.; Grimes, N.W.

    1999-12-01

    This paper reviews the crystal structure of compounds with the general formula AB{sub 2}X{sub 4}, which crystallize with the same atomic structure as the mineral spinel, MgAl{sub 2}O{sub 4}. Three degrees of freedom associated with the detailed atomic arrangements of spinels are considered here: (i) the lattice parameter, a; (ii) the anion parameter, u; and (iii) the cation inversion parameter, i. Oxide spinels are used as examples to explore the interrelationships between these parameters.

  19. Composite foam structures

    NASA Technical Reports Server (NTRS)

    Williams, Brian E. (Inventor); Brockmeyer, Jerry (Inventor); Tuffias, Robert H. (Inventor)

    2005-01-01

    A composite rigid foam structure that has a skin or coating on at least one of its surfaces. The skin is formed in situ by thermal spray techniques. The skin is bonded substantially throughout the surface of the porous substrate to the peripheries of the pores. The skin on the average does not penetrate the surface of the substrate by more than the depth of about 2 to 5 pores. Thus, thermal spraying the skin onto the rigid foam produces a composite that is tightly and uniformly bonded together without unduly increasing the weight of the composite structure. Both thermal conductivity and bonding are excellent.

  20. Structural brain defects.

    PubMed

    Whitehead, Matthew T; Fricke, Stanley T; Gropman, Andrea L

    2015-06-01

    Up to 14% of patients with congenital metabolic disease may show structural brain abnormalities from perturbation of cell proliferation, migration, and/or organization. Most inborn errors of metabolism have a postnatal onset. Abnormalities from genetic disease processes have a prenatal onset. Energy impairment, substrate insufficiency, cell membrane receptor and cell signaling abnormalities, and toxic byproduct accumulation are associations between genetic disorders and structural brain anomalies. Collective imaging patterns of brain abnormalities can provide clues to the underlying etiology. We review selected metabolic diseases associated with brain malformations and highlight characteristic clinical and imaging manifestations that help narrow the differential diagnosis. PMID:26042908

  1. Structural Margins Assessment Approach

    NASA Technical Reports Server (NTRS)

    Ryan, Robert S.

    1988-01-01

    A general approach to the structural design and verification used to determine the structural margins of the space vehicle elements under Marshall Space Flight Center (MSFC) management is described. The Space Shuttle results and organization will be used as illustrations for techniques discussed. Given also are: (1) the system analyses performed or to be performed by, and (2) element analyses performed by MSFC and its contractors. Analysis approaches and their verification will be addressed. The Shuttle procedures are general in nature and apply to other than Shuttle space vehicles.

  2. Structure of Serum Albumin

    NASA Technical Reports Server (NTRS)

    Carter, Daniel C.; Ho, Joseph X.

    1994-01-01

    Because of its availability, low cost, stability, and unusual ligand-binding properties, serum albumin has been one of the mst extensively studied and applied proteins in biochemistry. However, as a protein, albumin is far from typical, and the widespread interest in and application of albumin have not been balanced by an understanding of its molecular structure. Indeed, for more than 30 years structural information was surmised based solely on techniques such as hydrodynamics, low-angle X-ray scattering, and predictive methods.

  3. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1979-01-01

    A multifaceted program is described in which aeronautical, mechanical, and materials engineers interact to develop composite aircraft structures. Topics covered include: (1) the design of an advanced composite elevator and a proposed spar and rib assembly; (2) optimizing fiber orientation in the vicinity of heavily loaded joints; (3) failure mechanisms and delamination; (4) the construction of an ultralight sailplane; (5) computer-aided design; finite element analysis programs, preprocessor development, and array preprocessor for SPAR; (6) advanced analysis methods for composite structures; (7) ultrasonic nondestructive testing; (8) physical properties of epoxy resins and composites; (9) fatigue in composite materials, and (10) transverse thermal expansion of carbon/epoxy composites.

  4. Fire protection for relocatable structures

    SciTech Connect

    1995-06-01

    This standard supersedes DOE/EV-0043, ``Standard on Fire Protection for Portable Structures.`` It was revised to address the numerous types of relocatable structures, such as trailers, tension-supported structures, and tents being used by DOE and contractors.

  5. Structural interaction with control systems

    NASA Technical Reports Server (NTRS)

    Noll, R. B.; Zvara, J.

    1971-01-01

    A monograph which assesses the state of the art of space vehicle design and development is presented. The monograph presents criteria and recommended practices for determining the structural data and a mathematical structural model of the vehicle needed for accurate prediction of structure and control-system interaction; for design to minimize undesirable interactions between the structure and the control system; and for determining techniques to achieve the maximum desirable interactions and associated structural design benefits. All space vehicles are treated, including launch vehicles, spacecraft, and entry vehicles. Important structural characteristics which affect the structural model used for structural and control-system interaction analysis are given.

  6. Acicular photomultiplier photocathode structure

    DOEpatents

    Craig, Richard A.; Bliss, Mary

    2003-09-30

    A method and apparatus for increasing the quantum efficiency of a photomultiplier tube by providing a photocathode with an increased surface-to-volume ratio. The photocathode includes a transparent substrate, upon one major side of which is formed one or more large aspect-ratio structures, such as needles, cones, fibers, prisms, or pyramids. The large aspect-ratio structures are at least partially composed of a photoelectron emitting material, i.e., a material that emits a photoelectron upon absorption of an optical photon. The large aspect-ratio structures may be substantially composed of the photoelectron emitting material (i.e., formed as such upon the surface of a relatively flat substrate) or be only partially composed of a photoelectron emitting material (i.e., the photoelectron emitting material is coated over large aspect-ratio structures formed from the substrate material itself.) The large aspect-ratio nature of the photocathode surface allows for an effective increase in the thickness of the photocathode relative the absorption of optical photons, thereby increasing the absorption rate of incident photons, without substantially increasing the effective thickness of the photocathode relative the escape incidence of the photoelectrons.

  7. Design oriented structural analysis

    NASA Technical Reports Server (NTRS)

    Giles, Gary L.

    1994-01-01

    Desirable characteristics and benefits of design oriented analysis methods are described and illustrated by presenting a synoptic description of the development and uses of the Equivalent Laminated Plate Solution (ELAPS) computer code. ELAPS is a design oriented structural analysis method which is intended for use in the early design of aircraft wing structures. Model preparation is minimized by using a few large plate segments to model the wing box structure. Computational efficiency is achieved by using a limited number of global displacement functions that encompass all segments over the wing planform. Coupling with other codes is facilitated since the output quantities such as deflections and stresses are calculated as continuous functions over the plate segments. Various aspects of the ELAPS development are discussed including the analytical formulation, verification of results by comparison with finite element analysis results, coupling with other codes, and calculation of sensitivity derivatives. The effectiveness of ELAPS for multidisciplinary design application is illustrated by describing its use in design studies of high speed civil transport wing structures.

  8. Extremes of nuclear structure

    NASA Astrophysics Data System (ADS)

    1999-09-01

    With the advent of medium and large gamma detector arrays, it is now possible to look at nuclear structure at high rotational forces. The role of pairing correlations and their eventual breakdown, along with the shell effects have showed us the interesting physics for nuclei at high spins - superdeformation, shape co-existence, yrast traps, alignments and their dramatic effects on nuclear structure and so on. Nuclear structure studies have recently become even more exciting, due to efforts and possibilities to reach nuclei far off from the stability valley. Coupling of gamma ray arrays with 'filters', like neutron wall, charged particle detector array, gamma ray total energy and multiplicity castles, conversion electron spectrometers etc gives a great handle to study nuclei produced online with 'low' cross-sections. Recently we studied, nuclei in mass region 80 using an array of 8 germanium detectors in conjunction with the recoil mass analyser, HIRA at the Nuclear Science Centre and, most unexpectedly came across the phenomenon of identical bands, with two quasi-particle difference. The discovery of magnetic rotation is another highlight. Our study of light In nucleus, 107In brought us face to face with the 'dipole' bands. I plan to discuss some of these aspects. There is also an immensely important development - that of the 'radioactive ion beams'. The availability of RIB, will probably very dramatically influence our 'conventional' concept of nuclear structure. The exotic shapes of these exotic nuclei and some of their expected properties will also be touched upon.

  9. Generalized Structured Component Analysis

    ERIC Educational Resources Information Center

    Hwang, Heungsun; Takane, Yoshio

    2004-01-01

    We propose an alternative method to partial least squares for path analysis with components, called generalized structured component analysis. The proposed method replaces factors by exact linear combinations of observed variables. It employs a well-defined least squares criterion to estimate model parameters. As a result, the proposed method…

  10. Structural Pest Control.

    ERIC Educational Resources Information Center

    Kahn, M. S.; Hoffman, W. M.

    This manual is designed for those who seek certification as pesticide applicators for industrial, institutional, structural, and health-related pest control. It is divided into six sections covering general pest control, wood-destroying organisms, bird control, fumigation, rodent control, and industrial weed control. The manual gives information…

  11. Control Augmented Structural Synthesis

    NASA Technical Reports Server (NTRS)

    Lust, Robert V.; Schmit, Lucien A.

    1988-01-01

    A methodology for control augmented structural synthesis is proposed for a class of structures which can be modeled as an assemblage of frame and/or truss elements. It is assumed that both the plant (structure) and the active control system dynamics can be adequately represented with a linear model. The structural sizing variables, active control system feedback gains and nonstructural lumped masses are treated simultaneously as independent design variables. Design constraints are imposed on static and dynamic displacements, static stresses, actuator forces and natural frequencies to ensure acceptable system behavior. Multiple static and dynamic loading conditions are considered. Side constraints imposed on the design variables protect against the generation of unrealizable designs. While the proposed approach is fundamentally more general, here the methodology is developed and demonstrated for the case where: (1) the dynamic loading is harmonic and thus the steady state response is of primary interest; (2) direct output feedback is used for the control system model; and (3) the actuators and sensors are collocated.

  12. Agriculture Education. Agriculture Structures.

    ERIC Educational Resources Information Center

    Stuttgart Public Schools, AR.

    This curriculum guide is designed for group instruction of secondary agricultural education students enrolled in one or two semester-long courses in agriculture structures. The guide presents units of study in the following areas: (1) shop safety, (2) identification and general use of hand tools, (3) power tools, (4) carpentry, (5) blueprint…

  13. Probabilistic Structural Analysis Program

    NASA Technical Reports Server (NTRS)

    Pai, Shantaram S.; Chamis, Christos C.; Murthy, Pappu L. N.; Stefko, George L.; Riha, David S.; Thacker, Ben H.; Nagpal, Vinod K.; Mital, Subodh K.

    2010-01-01

    NASA/NESSUS 6.2c is a general-purpose, probabilistic analysis program that computes probability of failure and probabilistic sensitivity measures of engineered systems. Because NASA/NESSUS uses highly computationally efficient and accurate analysis techniques, probabilistic solutions can be obtained even for extremely large and complex models. Once the probabilistic response is quantified, the results can be used to support risk-informed decisions regarding reliability for safety-critical and one-of-a-kind systems, as well as for maintaining a level of quality while reducing manufacturing costs for larger-quantity products. NASA/NESSUS has been successfully applied to a diverse range of problems in aerospace, gas turbine engines, biomechanics, pipelines, defense, weaponry, and infrastructure. This program combines state-of-the-art probabilistic algorithms with general-purpose structural analysis and lifting methods to compute the probabilistic response and reliability of engineered structures. Uncertainties in load, material properties, geometry, boundary conditions, and initial conditions can be simulated. The structural analysis methods include non-linear finite-element methods, heat-transfer analysis, polymer/ceramic matrix composite analysis, monolithic (conventional metallic) materials life-prediction methodologies, boundary element methods, and user-written subroutines. Several probabilistic algorithms are available such as the advanced mean value method and the adaptive importance sampling method. NASA/NESSUS 6.2c is structured in a modular format with 15 elements.

  14. Visual Narrative Structure

    ERIC Educational Resources Information Center

    Cohn, Neil

    2013-01-01

    Narratives are an integral part of human expression. In the graphic form, they range from cave paintings to Egyptian hieroglyphics, from the Bayeux Tapestry to modern day comic books (Kunzle, 1973; McCloud, 1993). Yet not much research has addressed the structure and comprehension of narrative images, for example, how do people create meaning out…

  15. Insulin structure and function.

    PubMed

    Mayer, John P; Zhang, Faming; DiMarchi, Richard D

    2007-01-01

    Throughout much of the last century insulin served a central role in the advancement of peptide chemistry, pharmacology, cell signaling and structural biology. These discoveries have provided a steadily improved quantity and quality of life for those afflicted with diabetes. The collective work serves as a foundation for the development of insulin analogs and mimetics capable of providing more tailored therapy. Advancements in patient care have been paced by breakthroughs in core technologies, such as semisynthesis, high performance chromatography, rDNA-biosynthesis and formulation sciences. How the structural and conformational dynamics of this endocrine hormone elicit its biological response remains a vigorous area of study. Numerous insulin analogs have served to coordinate structural biology and biochemical signaling to provide a first level understanding of insulin action. The introduction of broad chemical diversity to the study of insulin has been limited by the inefficiency in total chemical synthesis, and the inherent limitations in rDNA-biosynthesis and semisynthetic approaches. The goals of continued investigation remain the delivery of insulin therapy where glycemic control is more precise and hypoglycemic liability is minimized. Additional objectives for medicinal chemists are the identification of superagonists and insulins more suitable for non-injectable delivery. The historical advancements in the synthesis of insulin analogs by multiple methods is reviewed with the specific structural elements of critical importance being highlighted. The functional refinement of this hormone as directed to improved patient care with insulin analogs of more precise pharmacology is reported. PMID:17410596

  16. Chemical structure of interfaces

    NASA Technical Reports Server (NTRS)

    Grunthaner, F. J.

    1985-01-01

    The interfacial structure of silicon/dielectric and silicon/metal systems is particularly amenable to analysis using a combination of surface spectroscopies together with a variety of chemical structures of Si/SiO2, Si/SiO2Si3N4, Si/Si2N2O, Si/SiO2/Al, and Si/Native Oxide interfaces using high resolution (0.350 eV FWHM) X ray photoelectron spectroscopy. The general structure of these dielectric interfaces entails a monolayer chemical transition layer at the Si/dielectric boundary. Amorphous Si substrates show a wide variety of hydrogenated Si and Si(OH) sub x states that are not observed in thermal oxidation of single crystal material. Extended SiO2 layers greater than 8 A in thickness are shown to be stoichiometric SiO2, but to exhibit a wide variety of local network structures. In the nitrogen containing systems, an approach to stoichiometric oxynitride compounds with interesting impurity and electron trapping properties are seen. In native oxides, substantial topographical nonuniformity in oxide thickness and composition are found. Analysis of metal/oxide interfacial layers is accomplished by analytical removal of the Si substrate by UHV XeF2 dry etching methods.

  17. Manipulating Combinatorial Structures.

    ERIC Educational Resources Information Center

    Labelle, Gilbert

    This set of transparencies shows how the manipulation of combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities at every level of education from elementary school to university. The transparencies describe: (1) the importance and relations of combinatorics to science and…

  18. Secondary Structure Switch

    ERIC Educational Resources Information Center

    King, Angela G.

    2006-01-01

    Neurogenerative diseases like Alzheimer's disease and Parkinson's disease involve a transformation between two peptide and protein structures of alpha-helices and beta-sheets, where the peptide backbone can also participate in metal ion binding in addition to histidine residues. However, the complete absence of change in conformation of Coiled…

  19. LDR structural experiment definition

    NASA Technical Reports Server (NTRS)

    Russell, R. A.

    1988-01-01

    A system study to develop the definition of a structural flight experiment for a large precision segmented reflector on the Space Station was accomplished by the Boeing Aerospace Company for NASA's Langley Research Center. The objective of the study was to use a Large Deployable Reflector (LDR) baseline configuration as the basis for focusing an experiment definition, so that the resulting accommodation requirements and interface constraints could be used as part of the mission requirements data base for Space Station. The primary objectives of the first experiment are to construct the primary mirror support truss and to determine its structural and thermal characteristics. Addition of an optical bench, thermal shield and primary mirror segments, and alignment of the optical components, would occur on a second experiment. The structure would then be moved to the payload point system for pointing, optical control, and scientific optical measurement for a third experiment. Experiment 1 will deploy the primary support truss while it is attached to the instrument module structure. The ability to adjust the mirror attachment points and to attach several dummy primary mirror segments with a robotic system will also be demonstrated. Experiment 2 will be achieved by adding new components and equipment to experiment one. Experiment 3 will demonstrate advanced control strategies, active adjustment of the primary mirror alignment, and technologies associated with optical sensing.

  20. THE STRUCTURE OF RIFF.

    ERIC Educational Resources Information Center

    APPLEGATE, JOSEPH R.

    THE PURPOSE OF THIS DESCRIPTIVE STUDY IS TO DEFINE THE MAJOR STRUCTURAL FEATURES OF RIFF, A BERBER LANGUAGE SPOKEN BY THE BERBER TRIBESMEN OF THE RIF IN NORTHERN MOROCCO. THE DESCRIPTION IS PRESENTED IN THREE PARTS--PHONOLOGY, MORPHOLOGY, AND SYNTAX. THE PHONEMES ARE DESCRIBED IN TERMS OF DISTINCTIVE FEATURES. PHARYNGEALIZATION AND TENSION ARE…

  1. Structured Sensory Trauma Interventions

    ERIC Educational Resources Information Center

    Steele, William; Kuban, Caelan

    2010-01-01

    This article features the National Institute of Trauma and Loss in Children (TLC), a program that has demonstrated via field testing, exploratory research, time series studies, and evidence-based research studies that its Structured Sensory Intervention for Traumatized Children, Adolescents, and Parents (SITCAP[R]) produces statistically…

  2. Heat exchange enhancement structure

    SciTech Connect

    Cornelison, R.C.; Kreith, F.

    1980-12-02

    A passive heat exchange enhancement structure which operates by free convection includes a flat mounting portion having a plurality of integral fins bent outwardly from one side edge thereof. The mounting portion is securable around a stovepipe, to a flat surface or the like for transferring heat from the pipe through the fins to the surrounding air by rotation-enhanced free convection.

  3. Bootstrapping structured page segmentation

    NASA Astrophysics Data System (ADS)

    Ma, Huanfeng; Doermann, David S.

    2003-01-01

    In this paper, we present an approach to the bootstrap learning of a page segmentation model. The idea evolves from attempts to segment dictionaries that often have a consistent page structure, and is extended to the segmentation of more general structured documents. In cases of highly regular structure, the layout can be learned from examples of only a few pages. The system is first trained using a small number of samples, and a larger test set is processed based on the training result. After making corrections to a selected subset of the test set, these corrected samples are combined with the original training samples to generate bootstrap samples. The newly created samples are used to retrain the system, refine the learned features and resegment the test samples. This procedure is applied iteratively until the learned parameters are stable. Using this approach, we do not need to initially provide a large set of training samples. We have applied this segmentation to many structured documents such as dictionaries, phone books, spoken language transcripts, and obtained satisfying segmentation performance.

  4. Aquarius main structure configuration

    NASA Astrophysics Data System (ADS)

    Eremenko, A.

    The Aquarius/SAC-D Observatory is a joint US-Argentine mission to map the salinity at the ocean surface. This information is critical to improving our understanding of two major components of Earth's climate system - the water cycle and ocean circulation. By measuring ocean salinity from space, the Aquarius/SAC-D Mission will provide new insights into how the massive natural exchange of freshwater between the ocean, atmosphere and sea ice influences ocean circulation, weather and climate. Aquarius is the primary instrument on the SAC-D spacecraft. It consists of a Passive Microwave Radiometer to detect the surface emission that is used to obtain salinity and an Active Scatterometer to measure the ocean waves that affect the precision of the salinity measurement. The Aquarius Primary Structure houses instrument electronics, feed assemblies, and supports a deployable boom with a 2.5 m Reflector, and provides the structural interface to the SAC-D Spacecraft. The key challenge for the Aquarius main structure configuration is to satisfy the needs of component accommodations, ensuring that the instrument can meet all operational, pointing, environmental, and launch vehicle requirements. This paper describes the evolution of the Aquarius main structure configuration, the challenges of balancing the conflicting requirements, and the major configuration driving decisions and compromises.

  5. Structural Equation Model Trees

    ERIC Educational Resources Information Center

    Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

    2013-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree…

  6. Structured and Unstructured Learning.

    ERIC Educational Resources Information Center

    1996

    This document contains four papers presented at a sympoisum on structured and unstructured learning moderated by Catherine Sleezer at the 1996 conference of the Academy of Human Resource Development (AHRD). "Designing Experiential Learning into Organizational Work Life: Proposing a Framework for Theory and Research" (Cheri Maben-Crouch) proposes a…

  7. Structuralism and the Classroom.

    ERIC Educational Resources Information Center

    Beer, Norman

    1983-01-01

    Argues that structuralism needs to be given a wider base than that of the highly specialized studies that are usually cited as examples. Rather, extension should be made philosophically, in the direction of phenomenology, and, practically, with some of the work being done in linguistics. (HOD)

  8. Quark structure of nuclei

    SciTech Connect

    Blankenbecler, R.

    1981-01-01

    A brief review is given of selected topics involved in the relativistic quark structure of nuclei such as the infinite momentum variables, scaling variables, counting rules, forward-backward variables, thermodynamic-like limit, QCD effects, higher quark bags, confinement, and many unanswered questions.

  9. Science as Structured Imagination

    ERIC Educational Resources Information Center

    De Cruz, Helen; De Smedt, Johan

    2010-01-01

    This paper offers an analysis of scientific creativity based on theoretical models and experimental results of the cognitive sciences. Its core idea is that scientific creativity--like other forms of creativity--is structured and constrained by prior ontological expectations. Analogies provide scientists with a powerful epistemic tool to overcome…

  10. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Wiberley, S. E.

    1978-01-01

    The purpose of the RPI composites program is to develop advanced technology in the areas of physical properties, structural concepts and analysis, manufacturing, reliability and life prediction. Concommitant goals are to educate engineers to design and use composite materials as normal or conventional materials. A multifaceted program was instituted to achieve these objectives.

  11. LDR structural experiment definition

    NASA Technical Reports Server (NTRS)

    Russell, Richard A.; Gates, Richard M.

    1988-01-01

    A study was performed to develop the definition of a structural flight experiment for a large precision segmented reflector that would utilize the Space Station. The objective of the study was to use the Large Deployable Reflector (LDR) baseline configuration for focusing on experiment definition activity which would identify the Space Station accommodation requirements and interface constraints. Results of the study defined three Space Station based experiments to demonstrate the technologies needed for an LDR type structure. The basic experiment configurations are the same as the JPL baseline except that the primary mirror truss is 10 meters in diameter instead of 20. The primary objectives of the first experiment are to construct the primary mirror support truss and to determine its structural and thermal characteristics. Addition of the optical bench, thermal shield and primary mirror segments and alignment of the optical components occur on the second experiment. The structure will then be moved to the payload pointing system for pointing, optical control and scientific optical measurement for the third experiment.

  12. Data Structures and Algorithms.

    ERIC Educational Resources Information Center

    Wirth, Niklaus

    1984-01-01

    Built-in data structures are the registers and memory words where binary values are stored; hard-wired algorithms are the fixed rules, embodied in electronic logic circuits, by which stored data are interpreted as instructions to be executed. Various topics related to these two basic elements of every computer program are discussed. (JN)

  13. Teaching Structure in Algebra

    ERIC Educational Resources Information Center

    Merlin, Ethan M.

    2013-01-01

    This article describes how the author has developed tasks for students that address the missed "essence of the matter" of algebraic transformations. Specifically, he has found that having students practice "perceiving" algebraic structure--by naming the "glue" in the expressions, drawing expressions using…

  14. Housing And Mounting Structure

    DOEpatents

    Anderson, Gene R.; Armendariz, Marcelino G.; Baca, Johnny R.F.; Bryan, Robert P.; Carson, Richard F.; Duckett, III, Edwin B.; McCormick, Frederick B.; Miller, Gregory V.; Peterson, David W.; Smith, Terrance T.

    2005-03-08

    This invention relates to an optical transmitter, receiver or transceiver module, and more particularly, to an apparatus for connecting a first optical connector to a second optical connector. The apparatus comprises: (1) a housing having at least a first end and at least a second end, the first end of the housing capable of receiving the first optical connector, and the second end of the housing capable of receiving the second optical connector; (2) a longitudinal cavity extending from the first end of the housing to the second end of the housing; and (3) an electromagnetic shield comprising at least a portion of the housing. This invention also relates to an apparatus for housing a flexible printed circuit board, and this apparatus comprises: (1) a mounting structure having at least a first surface and a second surface; (2) alignment ridges along the first and second surfaces of the mounting structure, the alignment ridges functioning to align and secure a flexible printed circuit board that is wrapped around and attached to the first and second surfaces of the mounting structure; and (3) a series of heat sink ridges adapted to the mounting structure, the heat sink ridges functioning to dissipate heat that is generated from the flexible printed circuit board.

  15. Hybrid composite laminate structures

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Lark, R. F. (Inventor)

    1977-01-01

    An invention which relates to laminate structures and specifically to essentially anisotropic fiber composite laminates is described. Metal foils are selectively disposed within the laminate to produce increased resistance to high velocity impact, fracture, surface erosion, and other stresses within the laminate.

  16. Adaptive building skin structures

    NASA Astrophysics Data System (ADS)

    Del Grosso, A. E.; Basso, P.

    2010-12-01

    The concept of adaptive and morphing structures has gained considerable attention in the recent years in many fields of engineering. In civil engineering very few practical applications are reported to date however. Non-conventional structural concepts like deployable, inflatable and morphing structures may indeed provide innovative solutions to some of the problems that the construction industry is being called to face. To give some examples, searches for low-energy consumption or even energy-harvesting green buildings are amongst such problems. This paper first presents a review of the above problems and technologies, which shows how the solution to these problems requires a multidisciplinary approach, involving the integration of architectural and engineering disciplines. The discussion continues with the presentation of a possible application of two adaptive and dynamically morphing structures which are proposed for the realization of an acoustic envelope. The core of the two applications is the use of a novel optimization process which leads the search for optimal solutions by means of an evolutionary technique while the compatibility of the resulting configurations of the adaptive envelope is ensured by the virtual force density method.

  17. Structured Programming: An Introduction.

    ERIC Educational Resources Information Center

    Moulton, Peter

    Designed for use by computer programming teachers, this booklet presents the concepts of structured programming and provides examples of how to implement this methodology, which provides a systematic way of organizing programs so that even large and complex programs are easier to understand and modify than unstructured programs. After a brief…

  18. Structured FORTRAN preprocessor

    NASA Technical Reports Server (NTRS)

    Austin, S.; Buckles, B.; Ryan, J. P.

    1980-01-01

    Structured-programming features simplify software design. Programmer needs only few control statements to code program in format easy to debug and maintain, freeing him/her from flow constraints of standard FORTRAN. Program is written in ANSI FORTRAN and is compatible with machine supporting FORTRAN compiler that accepts ANSI statements. It has been implemented on IBM 370.

  19. Imprinting artificial magnetic structures.

    SciTech Connect

    Lohstroh, W.

    1998-09-25

    Recently we created La/Fe multilayers with a helical magnetic structure imprinted from the conditions of growth rather than by the magnetic interactions between layers. Each sublayer was 30{angstrom} thick, and during deposition the sample was rotated in an external field of 3 Oe. a field strong enough to magnetize the Fe layer being deposited but not sufficient to perturb the magnetization of the Fe layers already grown. As a result adjacent Fe layers formed a helical structure with a chirality and periodicity determined by the rotational direction and speed of the substrate and the rate of deposition. Following this discovery, an extensive set of experiments (mainly using Kerr effect magnetometry and polarized neutron reflectivity) was undertaken to ascertain the stability of imprinted magnetic structures, and to understand the onset of magnetization during growth. La/Fe imprinted helical magnetic structures (of different La and Fe thicknesses) were found to be stable in time and to be permanently erased only by magnetic fields larger than 90 Oe.

  20. Simulation of phase structures

    SciTech Connect

    Lawson, J.

    1995-04-20

    This memo outlines a procedure developed by the author to extract information from phase measurements and produce a simulated phase structure for use in modeling optical systems, including characteristic optics for the Beamlet and NIF laser systems. The report includes an IDL program listing.

  1. Solid electrolyte structure

    DOEpatents

    Fraioli, Anthony V.

    1984-01-01

    A solid electrolyte structure for fuel cells and other electrochemical devices providing oxygen ion transfer by a multiplicity of exposed internal surfaces made of a composition containing an oxide of a multivalent transition metal and forming small pore-like passages sized to permit oxygen ion transfer while limiting the transfer of oxygen gas.

  2. Air Structures: Inflatable Alternatives

    ERIC Educational Resources Information Center

    Valerio, Joseph M.; And Others

    1973-01-01

    Describes and evaluates several avant garde'' examples of air structures. Included are a soft'' child's playpen, a pneudome that employs a water ballast for anchoring, a one-acre enclosed campus, an instant city'' constructed for an industrial design conference, and the Fuji Pavilion, at Expo '70 in Osaka, Japan, that was large enough to cover…

  3. Structural model of channelrhodopsin.

    PubMed

    Watanabe, Hiroshi C; Welke, Kai; Schneider, Franziska; Tsunoda, Satoshi; Zhang, Feng; Deisseroth, Karl; Hegemann, Peter; Elstner, Marcus

    2012-03-01

    Channelrhodopsins (ChRs) are light-gated cation channels that mediate ion transport across membranes in microalgae (vectorial catalysis). ChRs are now widely used for the analysis of neural networks in tissues and living animals with light (optogenetics). For elucidation of functional mechanisms at the atomic level, as well as for further engineering and application, a detailed structure is urgently needed. In the absence of an experimental structure, here we develop a structural ChR model based on several molecular computational approaches, capitalizing on characteristic patterns in amino acid sequences of ChR1, ChR2, Volvox ChRs, Mesostigma ChR, and the recently identified ChR of the halophilic alga Dunaliella salina. In the present model, we identify remarkable structural motifs that may explain fundamental electrophysiological properties of ChR2, ChR1, and their mutants, and in a crucial validation of the model, we successfully reproduce the excitation energy predicted by absorption spectra. PMID:22241469

  4. Grain structure and composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chapter 4 covers general information about structure and composition of cereal grains as well as the unique features of each cereal grain. Cereal grains are the fruits of cultivated grasses and members of Gramineae family. The fruit of a cereal is botanically known as caryopsis, featured by fusion...

  5. The Structured Classroom

    ERIC Educational Resources Information Center

    Ljusberg, Anna-Lena

    2011-01-01

    The aim of this article is to highlight the organisation of the remedial classroom. The data were collected from observations and semi-structured interviews with 10 teachers in remedial classes for children seen and treated as having concentration deficits. The teachers use primarily compensatory language that places the deficits in the pupils.…

  6. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1982-01-01

    Research in the basic composition, characteristics, and processng science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to problems. Detailed descriptions of the progress achieved in the various component parts of his program are presented.

  7. Cell Structure Study.

    ERIC Educational Resources Information Center

    Ekstrom, James V.

    2000-01-01

    Presents an activity in which students use microscopes and digital images to examine Elodea, a fresh water plant, before and after the process of plasmolysis, identify plant cellular structures before and after plasmolysis, and calculate the size of the plant's vacuole. (ASK)

  8. Elastically tailored composite structures

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Elastically tailored composite structures using out-of-autoclave processes. Several unsymetric autoclave-cured and electron-beam-cured composite laminates are compared. Cantilevered beam (unbalanced/asymetric laminate) used to demonstrate bend-twist coupling effects. Photographed in building 1145, photographic studio.

  9. Emerging Organizational Structures.

    ERIC Educational Resources Information Center

    Carchidi, Daniel M.; Peterson, Marvin W.

    2000-01-01

    Discussion of emerging higher educational organizational structures focuses on the increasing importance of distance education. Considers the emerging organizational landscape, three types of network organizations, six organization archetypes, organizational forms that support distance education, and implications for higher education planners. (DB)

  10. Structured Mechanical Collage.

    PubMed

    Huang, Zhe; Wang, Jiang; Fu, Hongbo; Lau, Rynson W H

    2014-07-01

    We present a method to build 3D structured mechanical collages consisting of numerous elements from the database given artist-designed proxy models. The construction is guided by some graphic design principles, namely unity, variety and contrast. Our results are visually more pleasing than previous works as confirmed by a user study. PMID:26357362

  11. Teaching Expository Text Structures

    ERIC Educational Resources Information Center

    Montelongo, Jose; Berber-Jimenez, Lola; Hernandez, Anita C.; Hosking, David

    2006-01-01

    Many students enter high school unskilled in the art of reading to learn from science textbooks. Even students who can read full-length novels often find science books difficult to read because students have relatively little practice with the various types of expository text structures used by such textbooks (Armbruster, 1991). Expository text…

  12. Whence Structured Propositions?

    ERIC Educational Resources Information Center

    Keller, Lorraine Juliano

    2012-01-01

    This thesis is a critical examination of "Structured Propositionalism" (SP), the view that propositions are complex entities composed of the semantic values of the (meaningful) parts of the sentences that express them. According to SP, propositions have constituents and are individuated by the identity and arrangement of their…

  13. Improved flux pinning by prefabricated SnO2 nanowires embedded in epitaxial YBa2Cu3Ox superconducting thin film tapes

    NASA Astrophysics Data System (ADS)

    Selvamanickam, V.; Mallick, R.; Tao, X.; Yao, Y.; Heydari Gharahcheshmeh, M.; Xu, A.; Zhang, Y.; Galstyan, E.; Majkic, G.

    2016-08-01

    We have developed processes to fabricate SnO2 nanowires on single crystalline-like buffer surfaces on flexible metal substrates with controlled alignment and density while eliminating undesired in-plane nanostructures that can be deleterious to subsequent epitaxial growth of the superconductor film. The in-plane nanostructures formed due to the mobility of gold catalyst on the nucleating surface and a two-step process was developed to restrict this mobility. Post-ion bombardment of the surface with randomly aligned SnO2 nanowires has resulted in re-alignment of the nanowires along the ion beam direction as well as in the removal of the undesired in-plane nanostructures. The most effective and reproducible control of SnO2 nanowire density with near absence of in-plane nanostructures was achieved by growth on single crystalline-like CeO2 surfaces and use of colloidal gold catalysts of 30 nm in size. YBa2Cu3Ox superconductor films epitaxially grown on the single crystalline-like surfaces with SnO2 nanowires exhibit a 50% improvement in critical current at 77 K in a magnetic field of 1 Tesla aligned along the orientation of the embedded nanowires.

  14. Studies of house-entering habits of mosquitoes in The Gambia, West Africa: experiments with prefabricated huts with varied wall apertures.

    PubMed

    Snow, W F

    1987-01-01

    The house-entering behaviour of nocturnal mosquitoes was studied in The Gambia. Mosquitoes were captured as they attacked man in the open and in experimental huts which comprised 1.8 m cube frames with corrugated iron roofs and plywood walls of various heights. Catches of all species were similar in the open and in a roofed, but unwalled, hut frame. The mosquitoes taken in catches in unwalled huts and others with wall heights of 0.6, 1.2 and 1.7 m (giving an 8 cm eaves-level entry slit) fell into two categories. The first group, which included the endophilic species Anopheles gambiae Giles s.l., An. melas Theobald and Mansonia spp. were only slightly affected by increasing wall height, but the second group, including the exophilic mosquitoes Aedes spp., An. pharoensis Theobald, Cx poicilipes (Theobald) and Cx thalassius Theobald showed a very marked progressive exclusion. In comparisons of catches in two huts with 8 cm entry slits at eaves or ground level, large numbers of An. pharoensis found access through the ground level entry but not at eaves level. No consistent difference could be demonstrated for other species. It is concluded that the house-entering behaviour which distinguishes endophagic mosquito species includes at least two distinct responses: flight upwards to eaves level and the passage from outside to indoors. It is also suggested that house entry as a component in host-seeking behaviour and indoor resting are distinct, but not necessarily exclusive, behavioural traits. PMID:2908761

  15. LUTE telescope structural design

    NASA Technical Reports Server (NTRS)

    Ruthven, Gregory

    1993-01-01

    The major objective of the Lunar Ultraviolet Transit Experiment (LUTE) Telescope Structural Design Study was to investigate the feasibility of designing an ultralightweight 1-m aperture system within optical performance requirements and mass budget constraints. This study uses the results from our previous studies on LUTE as a basis for further developing the LUTE structural architecture. After summarizing our results in Section 2, Section 3 begins with the overall logic we used to determine which telescope 'structural form' should be adopted for further analysis and weight estimates. Specific telescope component analysis showing calculated fundamental frequencies and how they compare with our derived requirements are included. 'First-order' component stress analyses to ensure telescope optical and structural component (i.e. mirrors & main bulkhead) weights are realistic are presented. Layouts of both the primary and tertiary mirrors showing dimensions that are consistent with both our weight and frequency calculations also form part of Section 3. Section 4 presents our calculated values for the predicted thermally induced primary-to-secondary mirror despace motion due to the large temperature range over which LUTE must operate. Two different telescope design approaches (one which utilizes fused quartz metering rods and one which assumes the entire telescope is fabricated from beryllium) are considered in this analysis. We bound the secondary mirror focus mechanism range (in despace) based on these two telescope configurations. In Section 5 we show our overall design of the UVTA (Ultraviolet Telescope Assembly) via an 'exploded view' of the sub-system. The 'exploded view' is annotated to help aid in the understanding of each sub-assembly. We also include a two view layout of the UVTA from which telescope and telescope component dimensions can be measured. We conclude our study with a set of recommendations not only with respect to the LUTE structural architecture

  16. Shock structures of astrospheres

    NASA Astrophysics Data System (ADS)

    Scherer, K.; Fichtner, H.; Kleimann, J.; Wiengarten, T.; Bomans, D. J.; Weis, K.

    2016-02-01

    Context. The interaction between a supersonic stellar wind and a (super-)sonic interstellar wind has recently been viewed with new interest. We here first give an overview of the modeling, which includes the heliosphere as an example of a special astrosphere. Then we concentrate on the shock structures of fluid models, especially of hydrodynamic (HD) models. More involved models taking into account radiation transfer and magnetic fields are briefly sketched. Even the relatively simple HD models show a rich shock structure, which might be observable in some objects. Aims: We employ a single-fluid model to study these complex shock structures, and compare the results obtained including heating and cooling with results obtained without these effects. Furthermore, we show that in the hypersonic case valuable information of the shock structure can be obtained from the Rankine-Hugoniot equations. Methods: We solved the Euler equations for the single-fluid case and also for a case including cooling and heating. We also discuss the analytical Rankine-Hugoniot relations and their relevance to observations. Results: We show that the only obtainable length scale is the termination shock distance. Moreover, the so-called thin shell approximation is usually not valid. We present the shock structure in the model that includes heating and cooling, which differs remarkably from that of a single-fluid scenario in the region of the shocked interstellar medium. We find that the heating and cooling is mainly important in this region and is negligible in the regions dominated by the stellar wind beyond an inner boundary.

  17. Structure of metallurgical coke

    SciTech Connect

    Shapiro, F.L.; Makarov, G.N.; Sidogin, V.P.; Kovalenko, V.P.

    1984-01-01

    Obtaining carboniferous coke satisfying the requirements of the metallurgical production processes constitutes a complicated problem determined by correctness in selecting a technological coking process and selecting the starting coals. Changes in coal charge composition, method, and systems of coking show a considerable effect on the properties of the metallurgical coke. Moreover, each technological process in which coke is used gives rise to quite well-defined requirements as regards its physicochemical properties. The general property of the carboniferous materials, on which their technological properties depend, is the reactive capability, which, in turn, depends to a large extent on the structure (macro-, micro-, and fine structure), the degree of order in the structure, the presence and sizes of crystals, and the extent of development of the system. Therefore, the structure can and must be one of the basic criteria of evaluating the quality when producing and using a specific metallurgical fuel and a reducing agent. A method of complex microscopic analysis of a carboniferous substance of carboniferous coke, iron and chemical etching methods, and optical and electronic (transmission and scanning) microscopy were used to study the structure of metallurgical coke produced by the Dnepropetrovsk Coking Plant. Coke belonging to 7 size-classes was studied microscopically: > 80, 80-60, 60-40, 40-25, 25-10, < 10, and 25-8 mm. The first size classes constitute the principal production of the plant, while the 25-8 mm class is produced to increase the quality of coke supplied to the ferroalloy plants. 5 references, 4 figures, 1 table.

  18. Titanium honeycomb structure. [for supersonic aircraft wing structure

    NASA Technical Reports Server (NTRS)

    Davis, R. A.; Elrod, S. D.; Lovell, D. T.

    1972-01-01

    A brazed titanium honeycomb sandwich system for supersonic transport wing cover panels provides the most efficient structure spanwise, chordwise, and loadwise. Flutter testing shows that high wing stiffness is most efficient in a sandwich structure. This structure also provides good thermal insulation if liquid fuel is carried in direct contact with the wing structure in integral fuel tanks.

  19. Structural Dynamics and Control Interaction of Flexible Structures

    NASA Technical Reports Server (NTRS)

    Ryan, Robert S. (Editor); Scofield, Harold N. (Editor)

    1987-01-01

    A workshop on structural dynamics and control interaction of flexible structures was held to promote technical exchange between the structural dynamics and control disciplines, foster joint technology, and provide a forum for discussing and focusing critical issues in the separate and combined areas. Issues and areas of emphasis were identified in structure-control interaction for the next generation of flexible systems.

  20. Computer-based structure generation

    NASA Astrophysics Data System (ADS)

    Korytko, Andrey A.

    The program HOUDINI has been designed to construct all structures consistent with structural implications of spectroscopic and other properties of an unknown molecule. With the advent of HOUDINI, a new method of computer structure generation, called convergent structure generation, has been developed that addresses the limitations of earlier methods. Several features of HOUDINI are noteworthy: an integrated application of the collective substructural information; the use of parallel atom groups for a highly efficient handling of alternative substructural inferences; and a managed structure generation procedure designed to build required structural features early in the process. A number of complex structure elucidation problems were solved using the HOUDINI-based comprehensive structure elucidation system. The program performance suggests that convergent structure generation is effective in solving structure problems where much of the input to the structure generator is highly ambiguous, i.e., expressed as families of alternative substructural inferences.

  1. Lewis Structures Technology, 1988. Volume 2: Structural Mechanics

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Lewis Structures Div. performs and disseminates results of research conducted in support of aerospace engine structures. These results have a wide range of applicability to practitioners of structural engineering mechanics beyond the aerospace arena. The engineering community was familiarized with the depth and range of research performed by the division and its academic and industrial partners. Sessions covered vibration control, fracture mechanics, ceramic component reliability, parallel computing, nondestructive evaluation, constitutive models and experimental capabilities, dynamic systems, fatigue and damage, wind turbines, hot section technology (HOST), aeroelasticity, structural mechanics codes, computational methods for dynamics, structural optimization, and applications of structural dynamics, and structural mechanics computer codes.

  2. Lewis Structures Technology, 1988. Volume 1: Structural Dynamics

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The specific purpose of the symposium was to familiarize the engineering structures community with the depth and range of research performed by the Structures Division of the Lewis Research Center and its academic and industrial partners. Sessions covered vibration control, fracture mechanics, ceramic component reliability, parallel computing, nondestructive testing, dynamical systems, fatigue and damage, wind turbines, hot section technology, structural mechanics codes, computational methods for dynamics, structural optimization, and applications of structural dynamics.

  3. Structural Case Assignment in Korean

    ERIC Educational Resources Information Center

    Koak, Heeshin

    2012-01-01

    In this dissertation, I aim to provide a theory on the distribution of structural Case in Korean. I propose the following Structural Case Assignment Hypothesis (SCAH) regarding the assignment of structural Case: "Structural Case is assigned by phase heads (C: nominative; v: accusative) to every argument in the c-command domain of the phase…

  4. Composite mechanics for engine structures

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    1989-01-01

    Recent research activities and accomplishments at Lewis Research Center on composite mechanics for engine structures are summarized. The activities focused mainly on developing procedures for the computational simulation of composite intrinsic and structural behavior. The computational simulation encompasses all aspects of composite mechanics, advanced three-dimensional finite-element methods, damage tolerance, composite structural and dynamic response, and structural tailoring and optimization.

  5. Dependency Structures and Transformational Rules.

    ERIC Educational Resources Information Center

    Robinson, Jane J.

    In this paper the author shows that dependency grammars are not only equivalent to structure-free phrase-structure grammars (i.e., equally adequate), but are even more informative: they express both the "is a" relation which phrase-structure grammars express and the "governs" relation which phrase-structure grammars obscure. It is shown that…

  6. Multi-functional composite structures

    DOEpatents

    Mulligan, Anthony C.; Halloran, John; Popovich, Dragan; Rigali, Mark J.; Sutaria, Manish P.; Vaidyanathan, K. Ranji; Fulcher, Michael L.; Knittel, Kenneth L.

    2010-04-27

    Fibrous monolith processing techniques to fabricate multifunctional structures capable of performing more than one discrete function such as structures capable of bearing structural loads and mechanical stresses in service and also capable of performing at least one additional non-structural function.

  7. Whose structure is it anyway?

    PubMed

    Sebastian, L; Kuntz, G; Shocks, D

    1990-01-01

    While "structure" is a term that is widely used in psychiatric nursing practice, few nurse authors have clearly defined the concept. This article offers an operational definition of structure, and proposes a theoretical basis to the client's need for structure. A case presentation, as well as characteristics of an effective structure, are also described. PMID:2381756

  8. Composite mechanics for engine structures

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    1987-01-01

    Recent research activities and accomplishments at Lewis Research Center on composite mechanics for engine structures are summarized. The activities focused mainly on developing procedures for the computational simulation of composite intrinsic and structural behavior. The computational simulation encompasses all aspects of composite mechanics, advanced three-dimensional finite-element methods, damage tolerance, composite structural and dynamic response, and structural tailoring and optimization.

  9. Honeycomb-laminate composite structure

    NASA Technical Reports Server (NTRS)

    Gilwee, W. J., Jr.; Parker, J. A. (Inventor)

    1977-01-01

    A honeycomb-laminate composite structure was comprised of: (1) a cellular core of a polyquinoxaline foam in a honeycomb structure, and (2) a layer of a noncombustible fibrous material impregnated with a polyimide resin laminated on the cellular core. A process for producing the honeycomb-laminate composite structure and articles containing the honeycomb-laminate composite structure is described.

  10. Providing Structure: The Critical Element.

    ERIC Educational Resources Information Center

    Miller, Judith E.; And Others

    1996-01-01

    Discussion of course structure in active learning at the college level looks at ways level and type of structure can be varied and manipulated to meet challenges presented by a diverse student body. Issues discussed include the relationship of structure to cognitive style and development, fitting structure to content and objectives, and what can…

  11. Multi-functional composite structures

    DOEpatents

    Mulligan, Anthony C.; Halloran, John; Popovich, Dragan; Rigali, Mark J.; Sutaria, Manish P.; Vaidyanathan, K. Ranji; Fulcher, Michael L.; Knittel, Kenneth L.

    2004-10-19

    Fibrous monolith processing techniques to fabricate multifunctional structures capable of performing more than one discrete function such as structures capable of bearing structural loads and mechanical stresses in service and also capable of performing at least one additional non-structural function.

  12. Structural Amorphous Steels

    NASA Astrophysics Data System (ADS)

    Lu, Z. P.; Liu, C. T.; Thompson, J. R.; Porter, W. D.

    2004-06-01

    Recent advancement in bulk metallic glasses, whose properties are usually superior to their crystalline counterparts, has stimulated great interest in fabricating bulk amorphous steels. While a great deal of effort has been devoted to this field, the fabrication of structural amorphous steels with large cross sections has remained an alchemist’s dream because of the limited glass-forming ability (GFA) of these materials. Here we report the discovery of structural amorphous steels that can be cast into glasses with large cross-section sizes using conventional drop-casting methods. These new steels showed interesting physical, magnetic, and mechanical properties, along with high thermal stability. The underlying mechanisms for the superior GFA of these materials are discussed.

  13. Structure of exoplanets.

    PubMed

    Spiegel, David S; Fortney, Jonathan J; Sotin, Christophe

    2014-09-01

    The hundreds of exoplanets that have been discovered in the past two decades offer a new perspective on planetary structure. Instead of being the archetypal examples of planets, those of our solar system are merely possible outcomes of planetary system formation and evolution, and conceivably not even especially common outcomes (although this remains an open question). Here, we review the diverse range of interior structures that are both known and speculated to exist in exoplanetary systems--from mostly degenerate objects that are more than 10× as massive as Jupiter, to intermediate-mass Neptune-like objects with large cores and moderate hydrogen/helium envelopes, to rocky objects with roughly the mass of Earth. PMID:24379369

  14. Rigid collapsible dish structure

    NASA Technical Reports Server (NTRS)

    Palmer, William B. (Inventor); Giebler, Martin M. (Inventor)

    1982-01-01

    A collapsible dish structure composed of a plurality of rows of rigid radial petal assemblies concentric with the axis of the dish. The petal assemblies consist of a center petal and two side petals, the center petal hinged on an axis tangent to a circle concentric with the axis of the dish and the side petals hinged to the center petal at their mating edge. The center petal is foldable inwardly and the side petals rotate about their hinges such that the collapsed dish structure occupies a much smaller volume than the deployed dish. Means of controlling the shape of the dish to compensate for differential expansion of the deployed dish are also provided.

  15. NEUTRON SHIELDING STRUCTURE

    DOEpatents

    Mattingly, J.T.

    1962-09-25

    A lightweight neutron shielding structure comprises a honeycomb core which is filled with a neutron absorbing powder. The honeycomb core is faced with parallel planar facing sheets to form a lightweight rigid unit. Suitable absorber powders are selected from among the following: B, B/sub 4/C, B/sub 2/O/ sub 3/, CaB/sub 6/, Li/sub 2/CO3, LiOH, LiBO/sub 2/, Li/s ub 2/O. The facing sheets are constructed of a neutron moderating material, so that fast neutrons will be moderated while traversing the facing sheets, and ultimately be absorbed by the absorber powder in the honeycomb. Beryllium is a preferred moderator material for use in the facing sheets. The advantage of the structure is that it combines the rigidity and light weight of a honeycomb construction with the neutron absorption properties of boron and lithium. (AEC)

  16. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1982-01-01

    The promise of filamentary composite materials, whose development may be considered as entering its second generation, continues to generate intense interest and applications activity. Fiber reinforced composite materials offer substantially improved performance and potentially lower costs for aerospace hardware. Much progress has been achieved since the initial developments in the mid 1960's. Rather limited applications to primary aircraft structure have been made, however, mainly in a material-substitution mode on military aircraft, except for a few experiments currently underway on large passenger airplanes in commercial operation. To fulfill the promise of composite materials completely requires a strong technology base. NASA and AFOSR recognize the present state of the art to be such that to fully exploit composites in sophisticated aerospace structures, the technology base must be improved. This, in turn, calls for expanding fundamental knowledge and the means by which it can be successfully applied in design and manufacture.

  17. Cosmological structure formation

    NASA Technical Reports Server (NTRS)

    Schramm, David N.

    1991-01-01

    A summary of the current forefront problem of physical cosmology, the formation of structures (galaxies, clusters, great walls, etc.) in the universe is presented. Solutions require two key ingredients: (1) matter; and (2) seeds. Regarding the matter, it now seems clear that both baryonic and non-baryonic matter are required. Whether the non-baryonic matter is hot or cold depends on the choice of seeds. Regarding the seeds, both density fluctuations and topological defects are discussed. The combination of isotropy of the microwave background and the recent observations indicating more power on large scales have severly constrained, if not eliminated, Gaussian fluctuations with equal power on all scales, regardless of the eventual resolution of both the matter and seed questions. It is important to note that all current structure formation ideas require new physics beyond SU(3) x SU(2) x U(1).

  18. The adaptable lyonsite structure.

    PubMed

    Smit, Jared P; Stair, Peter C; Poeppelmeier, Kenneth R

    2006-08-01

    Crystal frameworks that can accommodate a wide range of elements, oxidation states, and stoichiometries are an important component of solid-state chemistry. These frameworks allow for unique comparisons of different metal-cation compositions with identical atomic arrangements. The mineral Lyonsite, alpha-Cu(3)Fe(4)(VO(4))(6), is emerging as the archetypal framework structure for a large class of materials, similar to known frameworks such as perovskite, garnet, apatite, and spinel. The new lyonsite-type oxides Li(2.82)Hf(0.795)Mo(3)O(12) and Li(3.35)Ta(0.53)Mo(3)O(12), in which hafnium and tantalum retain their highest oxidation states, are presented to advance the concept of the lyonsite structure as an adaptable framework. PMID:16755622

  19. COI Structural Analysis Presentation

    NASA Technical Reports Server (NTRS)

    Cline, Todd; Stahl, H. Philip (Technical Monitor)

    2001-01-01

    This report discusses the structural analysis of the Next Generation Space Telescope Mirror System Demonstrator (NMSD) developed by Composite Optics Incorporated (COI) in support of the Next Generation Space Telescope (NGST) project. The mirror was submitted to Marshall Space Flight Center (MSFC) for cryogenic testing and evaluation. Once at MSFC, the mirror was lowered to approximately 40 K and the optical surface distortions were measured. Alongside this experiment, an analytical model was developed and used to compare to the test results. A NASTRAN finite element model was provided by COI and a thermal model was developed from it. Using the thermal model, steady state nodal temperatures were calculated based on the predicted environment of the large cryogenic test chamber at MSFC. This temperature distribution was applied in the structural analysis to solve for the deflections of the optical surface. Finally, these deflections were submitted for optical analysis and comparison to the interferometer test data.

  20. Materials and structures technology

    NASA Technical Reports Server (NTRS)

    Signorelli, R. A.; Glasgow, T. K.; Halford, G. R.; Levine, S. R.

    1979-01-01

    Materials and structures performance limitations, particularly for the hot section of the engine in which these limitations limit the life of components, are considered. Failure modes for components such as blades, vanes, and combustors and how they are affected by the environment for such components are discussed. Methods used to improve the materials used for such components are: (1) application of directional structures to turbine components for high strength at high temperatures; (2) improved coatings to increase oxidation and corrosion resistance; (3) increase strength and stiffness with reduced weight by applying higher specific properties of composite materials; and (4) cost effective processing such as near net shape powder methods applied to disks. Life prediction techniques developed to predict component life accurately in advance of service and progress in improving the intermediate and cold section components of turbine engines are covered.

  1. Core assembly storage structure

    DOEpatents

    Jones, Jr., Charles E.; Brunings, Jay E.

    1988-01-01

    A structure for the storage of core assemblies from a liquid metal-cooled nuclear reactor. The structure comprises an enclosed housing having a substantially flat horizontal top plate, a bottom plate and substantially vertical wall members extending therebetween. A plurality of thimble members extend downwardly through the top plate. Each thimble member is closed at its bottom end and has an open end adjacent said top plate. Each thimble member has a length and diameter greater than that of the core assembly to be stored therein. The housing is provided with an inlet duct for the admission of cooling air and an exhaust duct for the discharge of air therefrom, such that when hot core assemblies are placed in the thimbles, the heat generated will by convection cause air to flow from the inlet duct around the thimbles and out the exhaust duct maintaining the core assemblies at a safe temperature without the necessity of auxiliary powered cooling equipment.

  2. REACTOR MODERATOR STRUCTURE

    DOEpatents

    Fraas, A.P.; Tudor, J.J.

    1963-08-01

    An improved moderator structure for nuclear reactors consists of moderator blocks arranged in horizontal layers to form a multiplicity of vertically stacked columns of blocks. The blocks in each vertical column are keyed together, and a ceramic grid is disposed between each horizontal layer of blocks. Pressure plates cover- the lateral surface of the moderator structure in abutting relationship with the peripheral terminal lengths of the ceramic grids. Tubular springs are disposed between the pressure plates and a rigid external support. The tubular springs have their axes vertically disposed to facilitate passage of coolant gas through the springs and are spaced apart a selected distance such that at sonae preselected point of spring deflection, the sides of the springs will contact adjacent springs thereby causing a large increase in resistance to further spring deflection. (AEC)

  3. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1984-01-01

    Progress is reported in studies of constituent materials composite materials, generic structural elements, processing science technology, and maintaining long-term structural integrity. Topics discussed include: mechanical properties of high performance carbon fibers; fatigue in composite materials; experimental and theoretical studies of moisture and temperature effects on the mechanical properties of graphite-epoxy laminates and neat resins; numerical investigations of the micromechanics of composite fracture; delamination failures of composite laminates; effect of notch size on composite laminates; improved beam theory for anisotropic materials; variation of resin properties through the thickness of cured samples; numerical analysis composite processing; heat treatment of metal matrix composites, and the RP-1 and RP2 gliders of the sailplane project.

  4. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, Robert G.; Wiberley, Stephen E.

    1987-01-01

    The development and application of composite materials to aerospace vehicle structures which began in the mid 1960's has now progressed to the point where what can be considered entire airframes are being designed and built using composites. Issues related to the fabrication of non-resin matrix composites and the micro, mezzo and macromechanics of thermoplastic and metal matrix composites are emphasized. Several research efforts are presented. They are entitled: (1) The effects of chemical vapor deposition and thermal treatments on the properties of pitch-based carbon fiber; (2) Inelastic deformation of metal matrix laminates; (3) Analysis of fatigue damage in fibrous MMC laminates; (4) Delamination fracture toughness in thermoplastic matrix composites; (5) Numerical investigation of the microhardness of composite fracture; and (6) General beam theory for composite structures.

  5. Network structure controls noise

    NASA Astrophysics Data System (ADS)

    Das, Jayajit; Raychaudhuri, Subhadip

    2004-03-01

    Biochemical reactions often involve low copy number of reactant molecules. Bio-networks, however, control the intrinsic noise arising from the fluctuations of low copy number of reactant molecules quite efficiently to perform their job in a robust manner. Network structures may be very crucial in the effective modulation of fluctuation effects. We investigate the interplay between the network structure and the noise behavior in signal transduction networks using Stochastic simulations. Some of the recurrent modules in biological networks seem to be vital in noise control. We correlate the effect of those modules to the function of the global topology of the network. This may explain why certain class of modules are so ubiquitous in Bio-networks.

  6. Structural assembly demonstration experiment

    NASA Technical Reports Server (NTRS)

    Stokes, J. W.

    1982-01-01

    The experiment is of an operational variety, designed to assess crew capability in Large Space System (LSS) assembly. The six Structural Assembly Demonstration Experiment objectives include: (1) the establishment of a quantitative correlation between LSS neutral buoyancy simulation and on-orbit assembly operations in order to enhance the validity of those assembly simulations; (2) the quantitative study of the capabilities and mechanics of human assembly in an Extravehicular Activity environment; (3) the further corroboration of the LSS Assembly Analysis cost algorithm through the obtainment of hard data base information; (4) the verification of LSS assembly techniques and timeless, as well as the identification of crew imposed loads and assembly aid requirements and concepts; (5) verification of a Launch/Assembly Platform structure concept for other LSS missions; and (6) lastly, to advance thermal control concepts through a flexible heat pipe.

  7. Alignments of RNA structures.

    PubMed

    Blin, Guillaume; Denise, Alain; Dulucq, Serge; Herrbach, Claire; Touzet, Hélène

    2010-01-01

    We describe a theoretical unifying framework to express the comparison of RNA structures, which we call alignment hierarchy. This framework relies on the definition of common supersequences for arc-annotated sequences and encompasses the main existing models for RNA structure comparison based on trees and arc-annotated sequences with a variety of edit operations. It also gives rise to edit models that have not been studied yet. We provide a thorough analysis of the alignment hierarchy, including a new polynomial-time algorithm and an NP-completeness proof. The polynomial-time algorithm involves biologically relevant edit operations such as pairing or unpairing nucleotides. It has been implemented in a software, called gardenia, which is available at the Web server http://bioinfo.lifl.fr/RNA/gardenia. PMID:20431150

  8. Structure of random foam.

    SciTech Connect

    Reinelt, Douglas A.; van Swol, Frank B.; Kraynik, Andrew Michael

    2004-06-01

    The Surface Evolver was used to compute the equilibrium microstructure of dry soap foams with random structure and a wide range of cell-size distributions. Topological and geometric properties of foams and individual cells were evaluated. The theory for isotropic Plateau polyhedra describes the dependence of cell geometric properties on their volume and number of faces. The surface area of all cells is about 10% greater than a sphere of equal volume; this leads to a simple but accurate theory for the surface free energy density of foam. A novel parameter based on the surface-volume mean bubble radius R32 is used to characterize foam polydispersity. The foam energy, total cell edge length, and average number of faces per cell all decrease with increasing polydispersity. Pentagonal faces are the most common in monodisperse foam but quadrilaterals take over in highly polydisperse structures.

  9. Structure Size Enhanced Histogram

    NASA Astrophysics Data System (ADS)

    Wesarg, Stefan; Kirschner, Matthias

    Direct volume visualization requires the definition of transfer functions (TFs) for the assignment of opacity and color. Multi-dimensional TFs are based on at least two image properties, and are specified by means of 2D histograms. In this work we propose a new type of a 2D histogram which combines gray value with information about the size of the structures. This structure size enhanced (SSE) histogram is an intuitive approach for representing anatomical features. Clinicians — the users we are focusing on — are much more familiar with selecting features by their size than by their gradient magnitude value. As a proof of concept, we employ the SSE histogram for the definition of two-dimensional TFs for the visualization of 3D MRI and CT image data.

  10. Air cathode structure manufacture

    DOEpatents

    Momyer, William R.; Littauer, Ernest L.

    1985-01-01

    An improved air cathode structure for use in primary batteries and the like. The cathode structure includes a matrix active layer, a current collector grid on one face of the matrix active layer, and a porous, nonelectrically conductive separator on the opposite face of the matrix active layer, the collector grid and separator being permanently bonded to the matrix active layer. The separator has a preselected porosity providing low IR losses and high resistance to air flow through the matrix active layer to maintain high bubble pressure during operation of the battery. In the illustrated embodiment, the separator was formed of porous polypropylene. A thin hydrophobic film is provided, in the preferred embodiment, on the current collecting metal grid.

  11. Diagnosable structured logic array

    NASA Technical Reports Server (NTRS)

    Whitaker, Sterling (Inventor); Miles, Lowell (Inventor); Gambles, Jody (Inventor); Maki, Gary K. (Inventor)

    2009-01-01

    A diagnosable structured logic array and associated process is provided. A base cell structure is provided comprising a logic unit comprising a plurality of input nodes, a plurality of selection nodes, and an output node, a plurality of switches coupled to the selection nodes, where the switches comprises a plurality of input lines, a selection line and an output line, a memory cell coupled to the output node, and a test address bus and a program control bus coupled to the plurality of input lines and the selection line of the plurality of switches. A state on each of the plurality of input nodes is verifiably loaded and read from the memory cell. A trusted memory block is provided. The associated process is provided for testing and verifying a plurality of truth table inputs of the logic unit.

  12. Structure of exoplanets

    PubMed Central

    Spiegel, David S.; Fortney, Jonathan J.; Sotin, Christophe

    2014-01-01

    The hundreds of exoplanets that have been discovered in the past two decades offer a new perspective on planetary structure. Instead of being the archetypal examples of planets, those of our solar system are merely possible outcomes of planetary system formation and evolution, and conceivably not even especially common outcomes (although this remains an open question). Here, we review the diverse range of interior structures that are both known and speculated to exist in exoplanetary systems—from mostly degenerate objects that are more than 10× as massive as Jupiter, to intermediate-mass Neptune-like objects with large cores and moderate hydrogen/helium envelopes, to rocky objects with roughly the mass of Earth. PMID:24379369

  13. Fractal structures and processes

    SciTech Connect

    Bassingthwaighte, J.B.; Beard, D.A.; Percival, D.B.; Raymond, G.M.

    1996-06-01

    Fractals and chaos are closely related. Many chaotic systems have fractal features. Fractals are self-similar or self-affine structures, which means that they look much of the same when magnified or reduced in scale over a reasonably large range of scales, at least two orders of magnitude and preferably more (Mandelbrot, 1983). The methods for estimating their fractal dimensions or their Hurst coefficients, which summarize the scaling relationships and their correlation structures, are going through a rapid evolutionary phase. Fractal measures can be regarded as providing a useful statistical measure of correlated random processes. They also provide a basis for analyzing recursive processes in biology such as the growth of arborizing networks in the circulatory system, airways, or glandular ducts. {copyright} {ital 1996 American Institute of Physics.}

  14. Birefringent phononic structures

    SciTech Connect

    Psarobas, I. E. Exarchos, D. A.; Matikas, T. E.

    2014-12-15

    Within the framework of elastic anisotropy, caused in a phononic crystal due to low crystallographic symmetry, we adopt a model structure, already introduced in the case of photonic metamaterials, and by analogy, we study the effect of birefringence and acoustical activity in a phononic crystal. In particular, we investigate its low-frequency behavior and comment on the factors which determine chirality by reference to this model.

  15. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, Robert G.; Wiberley, Stephen E.

    1988-01-01

    A decade long program to develop critical advanced composite technology in the areas of physical properties, structural concept and analysis, manufacturing, reliability, and life predictions is reviewed. Specific goals are discussed. The status of the chemical vapor deposition effects on carbon fiber properties; inelastic deformation of metal matrix laminates; fatigue damage in fibrous MMC laminates; delamination fracture toughness in thermoplastic matrix composites; and numerical analysis of composite micromechanical behavior are presented.

  16. Truss structure design

    NASA Technical Reports Server (NTRS)

    Daily, Carl S. (Inventor); Lees, Daniel A. (Inventor); McKitterick, Dennis Donald (Inventor)

    2000-01-01

    An integrally formed three-dimensional truss structure, including molds and methods for production of same, containing outer top and bottom plane surfaces thereof comprising interconnected rod segments integrally formed at their points of intersection on the outer top and bottom surfaces, the top and bottom surfaces also integrally joined together through additional interconnected rod segments passing through an integrally formed intersection, wherein the additional interconnected rod segments passing through the integrally formed intersection form a three-dimensional continuous array of triangles.

  17. Reference structure tomography

    NASA Astrophysics Data System (ADS)

    Brady, David J.; Pitsianis, Nikos P.; Sun, Xiaobai

    2004-07-01

    Reference structure tomography (RST) uses multidimensional modulations to encode mappings between radiating objects and measurements. RST may be used to image source-density distributions, estimate source parameters, or classify sources. The RST paradigm permits scan-free multidimensional imaging, data-efficient and computation-efficient source analysis, and direct abstraction of physical features. We introduce the basic concepts of RST and illustrate the use of RST for multidimensional imaging based on a geometric radiation model.

  18. Structural femtochemistry: experimental methodology.

    PubMed Central

    Williamson, J C; Zewail, A H

    1991-01-01

    The experimental methodology for structural femtochemistry of reactions is considered. With the extension of femtosecond transition-state spectroscopy to the diffraction regime, it is possible to obtain in a general way the trajectories of chemical reactions (change of internuclear separations with time) on the femtosecond time scale. This method, considered here for simple alkali halide dissociation, promises many applications to more complex reactions and to conformational changes. Alignment on the time scale of the experiments is also discussed. Images PMID:11607189

  19. Structure Formation in Astrophysics

    NASA Astrophysics Data System (ADS)

    Chabrier, Gilles

    2009-01-01

    Part I. Physical Processes and Numerical Methods Common to Structure Formations in Astrophysics: 1. The physics of turbulence E. Levêque; 2. The numerical simulation of turbulence W. Schmidt; 3. Numerical methods for radiation magnetohydrodynamics in astrophysics R. Klein and J. Stone; 4. The role of jets in the formation of planets, stars, and galaxies R. Banerjee, R. Pudritz and R. Ouyed; 5. Advanced numerical methods in astrophysical fluid dynamics A. Hujeirat and F. Heitsch; Part II. Structure and Star Formation in the Primordial Universe: 6. New frontiers in cosmology and galaxy formation challenges for the future R. Ellis and J. Silk; 7. Galaxy formation physics T. Abel, G. Bryan and R. Teyssier; 8. First stars formation, evolution, feedback effects V. Bromm, A. Ferrara and A. Heger; Part III. Contemporary Star and Brown Dwarf Formation: a) Cloud Formation and Fragmentation: 9. Diffuse interstellar medium and the formation of molecular clouds P. Hennebelle, M. Mac Low and E. Vazquez-Semadeni; 10. The formation of distributed and clustered stars in molecular clouds T. Megeath, Z. -Y. Li and A. Nordlund; b) Core Fragmentation and Star Formation: 11. The formation and evolution of prestellar cores P. André, S. Basu and S. Inutsuka; 12. Models for the formation of massive stars; Part IV. Protoplanetary Disks and Planet Formation M. Krumholz and I. Bonnell: 13. Observational properties of disks and young stellar objects G. Duchêne, F. Ménard, J. Muzzerolle and S. Mohanty; 14. Structure and dynamics of protoplanetary disks C. Dullemond, R. Durisen and J. Papaloizou; 15. Planet formation and evolution theory and observation Y. Alibert, I. Baraffe, W. Benz, G. Laughlin and S. Udry; 16. Planet formation assembling the puzzle G. Wurm and T. Guillot; Part V. Summary: 17. Open issues in small- and large-scale structure formation R. Klessen and M. Mac Low; 18. Final word E. Salpeter.

  20. Structure Formation in Astrophysics

    NASA Astrophysics Data System (ADS)

    Chabrier, Gilles

    2011-02-01

    Part I. Physical Processes and Numerical Methods Common to Structure Formations in Astrophysics: 1. The physics of turbulence E. Levêque; 2. The numerical simulation of turbulence W. Schmidt; 3. Numerical methods for radiation magnetohydrodynamics in astrophysics R. Klein and J. Stone; 4. The role of jets in the formation of planets, stars, and galaxies R. Banerjee, R. Pudritz and R. Ouyed; 5. Advanced numerical methods in astrophysical fluid dynamics A. Hujeirat and F. Heitsch; Part II. Structure and Star Formation in the Primordial Universe: 6. New frontiers in cosmology and galaxy formation challenges for the future R. Ellis and J. Silk; 7. Galaxy formation physics T. Abel, G. Bryan and R. Teyssier; 8. First stars formation, evolution, feedback effects V. Bromm, A. Ferrara and A. Heger; Part III. Contemporary Star and Brown Dwarf Formation: a) Cloud Formation and Fragmentation: 9. Diffuse interstellar medium and the formation of molecular clouds P. Hennebelle, M. Mac Low and E. Vazquez-Semadeni; 10. The formation of distributed and clustered stars in molecular clouds T. Megeath, Z. -Y. Li and A. Nordlund; b) Core Fragmentation and Star Formation: 11. The formation and evolution of prestellar cores P. André, S. Basu and S. Inutsuka; 12. Models for the formation of massive stars; Part IV. Protoplanetary Disks and Planet Formation M. Krumholz and I. Bonnell: 13. Observational properties of disks and young stellar objects G. Duchêne, F. Ménard, J. Muzzerolle and S. Mohanty; 14. Structure and dynamics of protoplanetary disks C. Dullemond, R. Durisen and J. Papaloizou; 15. Planet formation and evolution theory and observation Y. Alibert, I. Baraffe, W. Benz, G. Laughlin and S. Udry; 16. Planet formation assembling the puzzle G. Wurm and T. Guillot; Part V. Summary: 17. Open issues in small- and large-scale structure formation R. Klessen and M. Mac Low; 18. Final word E. Salpeter.

  1. Structural Analysis Made 'NESSUSary'

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Everywhere you look, chances are something that was designed and tested by a computer will be in plain view. Computers are now utilized to design and test just about everything imaginable, from automobiles and airplanes to bridges and boats, and elevators and escalators to streets and skyscrapers. Computer-design engineering first emerged in the 1970s, in the automobile and aerospace industries. Since computers were in their infancy, however, architects and engineers during the time were limited to producing only designs similar to hand-drafted drawings. (At the end of 1970s, a typical computer-aided design system was a 16-bit minicomputer with a price tag of $125,000.) Eventually, computers became more affordable and related software became more sophisticated, offering designers the "bells and whistles" to go beyond the limits of basic drafting and rendering, and venture into more skillful applications. One of the major advancements was the ability to test the objects being designed for the probability of failure. This advancement was especially important for the aerospace industry, where complicated and expensive structures are designed. The ability to perform reliability and risk assessment without using extensive hardware testing is critical to design and certification. In 1984, NASA initiated the Probabilistic Structural Analysis Methods (PSAM) project at Glenn Research Center to develop analysis methods and computer programs for the probabilistic structural analysis of select engine components for current Space Shuttle and future space propulsion systems. NASA envisioned that these methods and computational tools would play a critical role in establishing increased system performance and durability, and assist in structural system qualification and certification. Not only was the PSAM project beneficial to aerospace, it paved the way for a commercial risk- probability tool that is evaluating risks in diverse, down- to-Earth application

  2. Corneal structure and transparency

    PubMed Central

    Meek, Keith M.; Knupp, Carlo

    2015-01-01

    The corneal stroma plays several pivotal roles within the eye. Optically, it is the main refracting lens and thus has to combine almost perfect transmission of visible light with precise shape, in order to focus incoming light. Furthermore, mechanically it has to be extremely tough to protect the inner contents of the eye. These functions are governed by its structure at all hierarchical levels. The basic principles of corneal structure and transparency have been known for some time, but in recent years X-ray scattering and other methods have revealed that the details of this structure are far more complex than previously thought and that the intricacy of the arrangement of the collagenous lamellae provides the shape and the mechanical properties of the tissue. At the molecular level, modern technologies and theoretical modelling have started to explain exactly how the collagen fibrils are arranged within the stromal lamellae and how proteoglycans maintain this ultrastructure. In this review we describe the current state of knowledge about the three-dimensional stromal architecture at the microscopic level, and about the control mechanisms at the nanoscopic level that lead to optical transparency. PMID:26145225

  3. Structural Proteomics of Herpesviruses

    PubMed Central

    Leroy, Baptiste; Gillet, Laurent; Vanderplasschen, Alain; Wattiez, Ruddy

    2016-01-01

    Herpesviruses are highly prevalent viruses associated with numerous pathologies both in animal and human populations. Until now, most of the strategies used to prevent or to cure these infections have been unsuccessful because these viruses have developed numerous immune evasion mechanisms. Therefore, a better understanding of their complex lifecycle is needed. In particular, while the genome of numerous herpesviruses has been sequenced, the exact composition of virions remains unknown for most of them. Mass spectrometry has recently emerged as a central method and has permitted fundamental discoveries in virology. Here, we review mass spectrometry-based approaches that have recently allowed a better understanding of the composition of the herpesvirus virion. In particular, we describe strategies commonly used for proper sample preparation and fractionation to allow protein localization inside the particle but also to avoid contamination by nonstructural proteins. A collection of other important data regarding post-translational modifications or the relative abundance of structural proteins is also described. This review also discusses the poorly studied importance of host proteins in herpesvirus structural proteins and the necessity to develop a quantitative workflow to better understand the dynamics of the structural proteome. In the future, we hope that this collaborative effort will assist in the development of new strategies to fight these infections. PMID:26907323

  4. Hypersonic Materials and Structures

    NASA Technical Reports Server (NTRS)

    Glass, David E.

    2016-01-01

    Thermal protection systems (TPS) and hot structures are required for a range of hypersonic vehicles ranging from ballistic reentry to hypersonic cruise vehicles, both within Earth's atmosphere and non-Earth atmospheres. The focus of this presentation is on air breathing hypersonic vehicles in the Earth's atmosphere. This includes single-stage to orbit (SSTO), two-stage to orbit (TSTO) accelerators, access to space vehicles, and hypersonic cruise vehicles. This paper will start out with a brief discussion of aerodynamic heating and thermal management techniques to address the high heating, followed by an overview of TPS for rocket-launched and air-breathing vehicles. The argument is presented that as we move from rocket-based vehicles to air-breathing vehicles, we need to move away from the insulated airplane approach used on the Space Shuttle Orbiter to a wide range of TPS and hot structure approaches. The primary portion of the paper will discuss issues and design options for CMC TPS and hot structure components, including leading edges, acreage TPS, and control surfaces. The current state-of-the-art will be briefly discussed for some of the components.

  5. Parasites alter community structure.

    PubMed

    Wood, Chelsea L; Byers, James E; Cottingham, Kathryn L; Altman, Irit; Donahue, Megan J; Blakeslee, April M H

    2007-05-29

    Parasites often play an important role in modifying the physiology and behavior of their hosts and may, consequently, mediate the influence hosts have on other components of an ecological community. Along the northern Atlantic coast of North America, the dominant herbivorous snail Littorina littorea structures rocky intertidal communities through strong grazing pressure and is frequently parasitized by the digenean trematode Cryptocotyle lingua. We hypothesized that the effects of parasitism on host physiology would induce behavioral changes in L. littorea, which in turn would modulate L. littorea's influence on intertidal community composition. Specifically, we hypothesized that C. lingua infection would alter the grazing rate of L. littorea and, consequently, macroalgal communities would develop differently in the presence of infected versus uninfected snails. Our results show that uninfected snails consumed 40% more ephemeral macroalgal biomass than infected snails in the laboratory, probably because the digestive system of infected snails is compromised by C. lingua infection. In the field, this weaker grazing by infected snails resulted in significantly greater expansion of ephemeral macroalgal cover relative to grazing by uninfected snails. By decreasing the per-capita grazing rate of the dominant herbivore, C. lingua indirectly affects the composition of the macroalgal community and may in turn affect other species that depend on macroalgae for resources or habitat structure. In light of the abundance of parasites across systems, we suggest that, through trait-mediated indirect effects, parasites may be a common determinant of structure in ecological communities. PMID:17517667

  6. Magnetic structure of holmium

    NASA Astrophysics Data System (ADS)

    Pechan, M. J.; Stassis, C.

    1984-03-01

    The magnetic structure of high purity single crystals of holmium has been studied by neutron diffraction techniques. Although the general characteristics of the magnetic structure have been found to agree with earlier measurements, some discrepancies have been resolved and new features have been observed. The magnetic form factor has been measured and compared with relativistic atomic calculations. The low temperature structure (T<20 K) is that of a conical ferromagnet with wave vector (1/6)(2π/c) along the c axis. The basal plane moment is 9.7 μB and the c-axis ferromagnetic component is 1.6 μB at T=6 K. Bunching of the basal plane moments around the easy hexagonal direction has been observed below T=50 K. Evidence for asphericity in the magnetization density is presented and discussed. The wave vector of the basal plane modulation decreases monotonically with temperature in general accordance with the Elliott-Wedgewood theory. Several inflection points were observed, however, which correspond to commensurability with the chemical lattice. The measured temperature dependence of the c- and a-axis lattice constants shows significant magnetostriction. The possibility of a c-axis modulated moment is discussed.

  7. 7. Administrative structures.

    PubMed

    2014-05-01

    The basic systems of any society rarely can operate independently. Instead, they are dependent and often interdependent upon other entities. Such entities control the resources within their respective systems. Thus, coordination and control agencies require contracts or memoranda of understanding with these entities in order to assure access to the resources required during a crisis. These administrative structures include: (1) governmental institutions and agencies, including the military; (2) intergovernmental organisations; (3) nongovernmental organisations; (4) commercial private sector organisations; and (5) academic institutions. These dependencies create potential barriers to the provision of coordination and control including: (1) the complexity of the administrative structures with which coordination and control must interact; (2) the location of resources; (3) finding responsible person(s); (4) the competence and compatibility; (5) methods of access; (6) payment; (7) contracts and memoranda of understanding; (8) inventories of accessible resources; (9) competition for the mandate, power, and resources; and (10) jealousy. The need for potential interactions between administrative structures requires that agreements for the sharing of resources during crises be reached as part of planning and preparedness. Gaining an understanding of these relationships is an important area for research. PMID:24785804

  8. Structure of mammalian metallothionein

    SciTech Connect

    Kaegi, J.H.R.; Vasak, M.; Lerch, K.; Gilg, D.E.O.; Hunziker, P.; Bernhard, W.R.; Good, M.

    1984-03-01

    All mammalian metallothioneins characterized contain a single polypeptide chain of 61 amino acid residues, among them 20 cysteines providing the ligands for seven metal-binding sites. Native metallothioneins are usually heterogeneous in metal composition, with Zn, Cd, and Cu occurring in varying proportions. However, forms containing only a single metal species, i.e., Zn, Cd, Ni, Co, Hg, Pb, Bi, have now been prepared by in vitro reconstitution from the metal-free apoprotein. By spectroscopic analysis of such derivatives it was established that all cysteine residues participate in metal binding, that each metal ion is bound to four thiolate ligands, and that the symmetry of each complex is close to that of a tetrahedron. To satisfy the requirements of the overall Me/sub 7/(Cys/sup -/)/sub 20/ stoichiometry, the complexes must be combined to form metal-thiolate cluster structures. The actual spatial organization of the clusters and the polypeptide chain remains to be established. An attractive possibility is the arrangement of the tetrahedral metal-thiolates in adamantane-like structures surrounded by properly folded segments of the chain providing the ligands. /sup 1/H-NMR data and infrared absorption measurements are consistent with a tightly folded structure rich in ..beta..-type conformation. 79 references, 11 figures, 4 tables.

  9. Structural Proteomics of Herpesviruses.

    PubMed

    Leroy, Baptiste; Gillet, Laurent; Vanderplasschen, Alain; Wattiez, Ruddy

    2016-02-01

    Herpesviruses are highly prevalent viruses associated with numerous pathologies both in animal and human populations. Until now, most of the strategies used to prevent or to cure these infections have been unsuccessful because these viruses have developed numerous immune evasion mechanisms. Therefore, a better understanding of their complex lifecycle is needed. In particular, while the genome of numerous herpesviruses has been sequenced, the exact composition of virions remains unknown for most of them. Mass spectrometry has recently emerged as a central method and has permitted fundamental discoveries in virology. Here, we review mass spectrometry-based approaches that have recently allowed a better understanding of the composition of the herpesvirus virion. In particular, we describe strategies commonly used for proper sample preparation and fractionation to allow protein localization inside the particle but also to avoid contamination by nonstructural proteins. A collection of other important data regarding post-translational modifications or the relative abundance of structural proteins is also described. This review also discusses the poorly studied importance of host proteins in herpesvirus structural proteins and the necessity to develop a quantitative workflow to better understand the dynamics of the structural proteome. In the future, we hope that this collaborative effort will assist in the development of new strategies to fight these infections. PMID:26907323

  10. Visual narrative structure.

    PubMed

    Cohn, Neil

    2013-04-01

    Narratives are an integral part of human expression. In the graphic form, they range from cave paintings to Egyptian hieroglyphics, from the Bayeux Tapestry to modern day comic books (Kunzle, 1973; McCloud, 1993). Yet not much research has addressed the structure and comprehension of narrative images, for example, how do people create meaning out of sequential images? This piece helps fill the gap by presenting a theory of Narrative Grammar. We describe the basic narrative categories and their relationship to a canonical narrative arc, followed by a discussion of complex structures that extend beyond the canonical schema. This demands that the canonical arc be reconsidered as a generative schema whereby any narrative category can be expanded into a node in a tree structure. Narrative "pacing" is interpreted as a reflection of various patterns of this embedding: conjunction, left-branching trees, center-embedded constituencies, and others. Following this, diagnostic methods are proposed for testing narrative categories and constituency. Finally, we outline the applicability of this theory beyond sequential images, such as to film and verbal discourse, and compare this theory with previous approaches to narrative and discourse. PMID:23163777

  11. Nucleon spin structure

    NASA Astrophysics Data System (ADS)

    Zhu, Wei; Ruan, Jianhong

    2015-10-01

    This paper contains three parts relating to the nucleon spin structure in a simple picture of the nucleon: (i) The polarized gluon distribution in the proton is dynamically predicted starting from a low scale by using a nonlinear quantum chromodynamics (QCD) evolution equation — the Dokshitzer-Gribov-Lipatov-Altarelli-Paris (DGLAP) equation with the parton recombination corrections, where the nucleon is almost consisted only of valence quarks. We find that the contribution of the gluon polarization to the nucleon spin structure is much larger than the predictions of most other theories. This result suggests that a significant orbital angular momentum of the gluons is required to balance the gluon spin momentum. (ii) The spin structure function g1p of the proton is studied, where the perturbative evolution of parton distributions and nonperturbative vector meson dominance (VMD) model are used. We predict g1p asymptotic behavior at small x from lower Q2 to higher Q2. The results are compatible with the data including the early HERA estimations and COMPASS new results. (iii) The generalized Gerasimov-Drell-Hearn (GDH) sum rule is understood based on the polarized parton distributions of the proton with the higher twist contributions. A simple parameterized formula is proposed to clearly present the contributions of different components in the proton to Γ 1p(Q2). The results suggest a possible extended objects with size 0.2-0.3 fm inside the proton.

  12. Reflectional transformation for structural stiffness

    SciTech Connect

    Vashi, K.M.

    1990-01-01

    This paper presents a structural reflection-related transformation for structural stiffness. The stiffness transformation addresses reflection of a structure about any of the three coordinate planes and renders the desired stiffness matrix using a stiffness matrix for the same structure before reflection. This transformation is elegant and simple, provides an efficient and technically rigorous approach to derive the required stiffness matrix without structural remodeling, and can be readily programmed to quickly perform the required matrix manipulations. 2 figs.

  13. Adaptive structures to meet future requirements for large precision structures

    NASA Technical Reports Server (NTRS)

    Wada, B. K.; Fanson, J. L.; Garba, J. A.; Chen, G.-S.

    1989-01-01

    The role of adaptive structures in meeting the structural requirements for future NASA missions is described. Many of NASA's future missions require large precision truss type structures where prespecified locations on the structure must maintain micron level accuracies with respect to each other when subjected to manufacturing errors and static, thermal, and dynamic inputs. In many cases the incorporation of the adaptive structures concepts into the structural design to adjust the on-orbit structure will be the only feasible means to attain the desired accuracies. In order for the structures to be able to change structural characteristics on orbit they must be uncoupled and independent of the control system used to impart the required rigid body motion to the spacecraft.

  14. Infrared Structural Biology: Detect Functionally Important Structural Motions of Proteins

    NASA Astrophysics Data System (ADS)

    Xie, Aihua

    Proteins are dynamic. Lack of dynamic structures of proteins hampers our understanding of protein functions. Infrared structural biology (IRSB) is an emerging technology. There are several advantages of IRSB for mechanistic studies of proteins: (1) its excellent dynamic range (detecting structural motions from picoseconds to >= seconds); (2) its high structural sensitivity (detect tiny but functionally important structural motions such as proton transfer and changes in hydrogen bonding interaction); (3) its ability to detect different structural motions simultaneously. Successful development of infrared structural biology demands not only new experimental techniques (from infrared technologies to chemical synthesis and cell biology), but also new data processing (how to translate infrared signals into quantitative structural information of proteins). These topics will be discussed as well as examples of how to use IRSB to study structure-function relationship of proteins. This work was supported by NSF DBI1338097 and OCAST HR10-078.

  15. Recent results on structural control of an active precision structure

    NASA Technical Reports Server (NTRS)

    Chu, C. C.; Fanson, J. L.; Smith, R. S.

    1991-01-01

    This paper describes recent results in structural control of an active precision truss structure at JPL. The goal is to develop practical control methodology and to apply to active truss structures intended for high precision space-based optics applications. The active structure considered incorporates piezoelectric active members which apply control forces internal to the structure and thereby improve the structure's dimensional stability. Two approaches to structural control system design were investigated. The first approach uses only noncollocated measurements of acceleration at the location of a simulated optical component to achieve structural stabilization. The second approach is essentially the same as the first one except that a viscous damper was used in place of a truss member on the structure to improve the dampings of selected flexible modes. The corresponding experimental closed-loop results are presented in this paper.

  16. Geometry and evolution of structural traps formed by inversion structures

    SciTech Connect

    Mitra, S. )

    1994-07-01

    Inversion structures form by compressional reactivation of preexisting extensional structures. Experimental models and observations of natural structures are used to develop quantitative models for the geometry and kinematic evolution of inversion structures. Two main mechanisms of formation of inversion structures are analyzed: (1) fault-propagation folding on planar faults, and (2) fault-bend folding on listric faults. Inversion structures formed by fault-propagation folding are characterized by the upward termination of a basement fault into a tight fold and thickening of synextensional units into the basin. Inversion structures formed by fault-bend folding are characterized by open-fold geometries and thickening of synextensional units into the fault zone. Characteristic variations in fold geometry and bed thickness provide predictive models for interpreting the subsurface geometries of these two classes of inversion structures in areas with poor seismic data. Examples of both types of structures are described from the Taranaki basin, the southern North Sea, and the Kangean Basin.

  17. Weight estimation of unconventional structures by structural optimization

    NASA Technical Reports Server (NTRS)

    Miura, Hirokazu; Shyu, Albert

    1986-01-01

    Automated techniques are presented that are used in structural optimization technology, with emphasis on modifications of finite element models to obtain an optimal material distribution for minimum weight while satisfying the prescribed design requirements. It is anticipated that the future development of computer aided engineering (CAE) system will provide environments where structural analysis, a design optimization, and weight evaluation modules are integrated, sharing a common data base. Structural optimization capabilities obtained by integrating a finite element structural analysis program and a numerical optimization code are developed and applied to two illustrative examples: marine gear housing structural weight minimization and joined wing structures.

  18. Error Location in Structural Dynamic Model of a Rocket Structure

    NASA Astrophysics Data System (ADS)

    Sundararajan, T.; Sam, C.

    2012-06-01

    Structural dynamic characteristics of the aerospace structures are essential to obtain the structural responses due to dynamic loads during its mission. The structural dynamic parameters of the aerospace structures are frequencies, associated mode shape and damping. Usually finite element (FE) model of the aerospace structures are generated to estimate the frequencies and the associated mode shape. These FE models are validated by modal survey/ground resonance tests to ensure its completeness and correctness. The modeling deficiencies, if any, in these FE models have to be corrected. This paper describes the method to locate the FE modeling errors using residual force method.

  19. Structural Stability of Asteroids

    NASA Astrophysics Data System (ADS)

    Hirabayashi, Toshi

    This thesis develops a technique for analyzing the internal structure of an irregularly shaped asteroid. This research focuses on asteroid (216) Kleopatra, a few-hundred-kilometer-sized main belt asteroid spinning about its maximum moment of inertia axis with a rotation period of 5.385 hours, to motivate the techniques. While Ostro et al. [117] reported its dog bone-like shape, estimation of its size has been actively discussed. There are at least three different size estimates: Ostro et al., Descamps et al., and Marchis et al. Descamps et al. reported that (216) Kleopatra has satellites and obtained the mass of this object. This research consists of determination of possible failure modes of (216) Kleopatra and its subsequent detailed stress analysis, with each part including an estimation of the internal structure. The first part of this thesis considers the failure mode of Kleopatra and evaluates the size from it. Possible failure modes are modeled as either material shedding from the surface or plastic failure of the internal structure. The surface shedding condition is met when a zero-velocity curve with the same energy level as one of the dynamical equilibrium points attaches to the surface at the slowest spin period, while the plastic failure condition is characterized by extending the theorem by Holsapple (2008) that the yield condition of the averaged stress over the whole volume is identical to an upper bound for global failure. The prime result shows that while surface shedding does not occur at the current spin period and thus cannot result in the formation of the satellites, the neck may be situated near its plastic deformation state. From the failure condition, we also find that the size estimated by Descamps et al. (2011) is the most structurally stable. The second part of this thesis discusses finite element analyses with an assumption of an elastic-perfectly plastic material and a non-associated flow rule. The yield condition is modeled as the

  20. Structural verification for GAS experiments

    NASA Technical Reports Server (NTRS)

    Peden, Mark Daniel

    1992-01-01

    The purpose of this paper is to assist the Get Away Special (GAS) experimenter in conducting a thorough structural verification of its experiment structural configuration, thus expediting the structural review/approval process and the safety process in general. Material selection for structural subsystems will be covered with an emphasis on fasteners (GSFC fastener integrity requirements) and primary support structures (Stress Corrosion Cracking requirements and National Space Transportation System (NSTS) requirements). Different approaches to structural verifications (tests and analyses) will be outlined especially those stemming from lessons learned on load and fundamental frequency verification. In addition, fracture control will be covered for those payloads that utilize a door assembly or modify the containment provided by the standard GAS Experiment Mounting Plate (EMP). Structural hazard assessment and the preparation of structural hazard reports will be reviewed to form a summation of structural safety issues for inclusion in the safety data package.

  1. Repairs of composite structures

    NASA Astrophysics Data System (ADS)

    Roh, Hee Seok

    Repair on damaged composite panels was conducted. To better understand adhesively bonded repair, the study investigates the effect of design parameters on the joint strength. The design parameters include bondline length, thickness of adherend and type of adhesive. Adhesives considered in this study were tested to measure their tensile material properties. Three types of adhesively bonded joints, single strap, double strap, and single lap joint were considered under changing bondline lengths, thickness of adherend and type of adhesive. Based on lessons learned from bonded joints, a one-sided patch repair method for composite structures was conducted. The composite patch was bonded to the damaged panel by either film adhesive FM-73M or paste adhesive EA-9394 and the residual strengths of the repaired specimens were compared under varying patch sizes. A new repair method using attachments has been suggested to enhance the residual strength. Results obtained through experiments were analyzed using finite element analysis to provide a better repair design and explain the experimental results. It was observed that the residual strength of the repaired specimen was affected by patch length. Method for rapid repairs of damaged composite structures was investigated. The damage was represented by a circular hole in a composite laminated plate. Pre-cured composite patches were bonded with a quick-curing commercial adhesive near (rather than over) the hole. Tensile tests were conducted on specimens repaired with various patch geometries. The test results showed that, among the methods investigated, the best repair method restored over 90% of the original strength of an undamaged panel. The interfacial stresses in the adhesive zone for different patches were calculated in order to understand the efficiencies of the designs of these patch repairs. It was found that the composite patch that yielded the best strength had the lowest interfacial peel stress between the patch and

  2. Solar Coronal Structure Study

    NASA Technical Reports Server (NTRS)

    Bruner, Marilyn E.; Saba, Julia; Strong, Keith; Nitta, Nariaki; Harvey, Karen

    1997-01-01

    The subject of this investigation is the study the physics of the solar corona through the analysis of the EUV and UV data produced by two flights (12 May 1992 and 25 April 1994) of the Lockheed Solar Plasma Diagnostics Experiment (SPDE) sounding rocket payload, in combination with Yohkoh and groundbased data. These joint datasets are useful for understanding the physical state of the solar atmosphere from the photosphere to the corona at the time of the rocket flights. Each rocket flight produced both spectral and imaging data. Highlights of this initial year of the contract included compilation, scaling and co-alignment of image sets, substantial progress on the Bright Point study, initial work on the Active Region and Large Scale Structure studies, DRSC slit-aspect determination work and calibration activities. One paper was presented at the 1997 Annual Meeting of the AAS/SPD in Bozeman, Montana. An initial set of calibrated spectra were placed into the public domain via the World Wide Web. Three Quarterly Progress Reports have been submitted; progress for the fourth quarter of the contract is summarized in this Final Contract Report. The intent of the investigation is to compare the physics of small- and medium-scale structure with that of large-scale structures with weak fields. A study has been identified in each size domain. The calibration of the rocket data forms an important element of the work. Of equal importance is the slit-aspect solution, which determines the correspondence between locations along the spectrograph slit and points on the solar disk.

  3. Structural studies on resids

    SciTech Connect

    Strausz, O.P. . Dept. of Chemistry)

    1988-01-01

    Investigations aimed at elucidating structural elements in Alberta oil and asphaltenes and heavy ends have yielded important and unforeseen results. Athabasca asphaltene has been separated into five different molecular weight fractions, each of which was analyzed by high-resolution /sup 1/H and /sup 13/C NMR spectroscopy. In all these fractions, as well as in the whole asphaltene, the aliphatic and aromatic carbon and hydrogen types were determined quantitatively, from which it was concluded that there exists a large network of straight-chain aliphatic side chains and bridging units. Only 43% of the asphaltene is aromatic and the average n-alkyl chain length is 9. Further insights into the aspahaltene structure were obtained using the Ru(VIII)-catalyzed oxidation technique. This reagent selectively and quantitatively oxidizes aromatic carbons to CO/sub 2/ while converting side chains to alkanoic acids, alkyl bridging units to {alpha}, {omega}-dicarboxylic acids, and di- and triaromatic moieties to benzene polycarboxylic acids. In this way the authors were able to determine, quantitatively, the extents and concentration distributions of the numerous n-alkyl side chains and bridging units connected to aromatic nuclei, and of the aromatic clusters. Examination of the aromatic-free oxidized residue gave further information on the alkyl substituents attached to saturated, cyclic systems. A schematic model of the gross structural features of the asphaltene is presented. A brief overview of the heterocyclic compound classes identified in the asphaltene and maltene fractions of the bitumen is presented. The nature and concentration distributions of the carboxylic acids, sulfides and thiophenes in the two fractions are different and possible explanations for these observations are discussed.

  4. Unibody Composite Pressurized Structure

    NASA Technical Reports Server (NTRS)

    Rufer, Markus; Conger, Robert; Bauer, Thomas; Newman, John

    2013-01-01

    An integrated, generic unibody composite pressurized structure (UCPS) combined with a positive expulsion device (PED), consisting of an elastomeric bladder for monopropellant hydrazine, has been quasi-standardized for spacecraft use. The combination functions as an all-composite, non-metallic, propellant tank with bladder. The integrated UCPS combines several previous innovations - specifically, the linerless, all-composite cryogenic tank technology; all-composite boss; resin formulation; and integrated stringer system. The innovation combines the UCPS with an integrated propellant management device (PMD), the PED or bladder, to create an entirely unique system for in-space use. The UCPS is a pressure vessel that incorporates skirts, stringers, and other structures so that it is both an in-space hydrazine tank, and also a structural support system for a spacecraft in a single, all-composite unit. This innovation builds on the progress in the development of a previous SBIR (Small Business Innovation Research) Phase I with Glenn Research Center and an SBIR III with Johnson Space Center that included the fabrication of two 42-in. (˜107-cm) diameter all-composite cryogenic (LOX and liquid methane) UCPS test tanks for a lunar lander. This Phase II provides hydra zine compatibility testing of the elastomeric bladder, a see-through PED to validate the expulsion process and model, and a complete UCPS-based PED with stringers and skirts that will be used to conduct initial qualification and expulsion tests. This extends the UCPS technology to include hydrazine-based, in-space pro - pulsion applications and can also be used for electric propulsion. This innovation creates a system that, in comparison to the traditional approach, is lower in weight, cost, volume, and production time; is stronger; and is capable of much higher pressures. It also has fewer failure modes, and is applicable to both chemical and electric propulsion systems.

  5. High Temperature Structural Foam

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S.; Baillif, Faye F.; Grimsley, Brian W.; Marchello, Joseph M.

    1997-01-01

    The Aerospace Industry is experiencing growing demand for high performance polymer foam. The X-33 program needs structural foam insulation capable of retaining its strength over a wide range of environmental conditions. The High Speed Research Program has a need for low density core splice and potting materials. This paper reviews the state of the art in foam materials and describes experimental work to fabricate low density, high shear strength foam which can withstand temperatures from -220 C to 220 C. Commercially available polymer foams exhibit a wide range of physical properties. Some with densities as low as 0.066 g/cc are capable of co-curing at temperatures as high as 182 C. Rohacell foams can be resin transfer molded at temperatures up to 180 C. They have moduli of elasticity of 0.19 MPa, tensile strengths of 3.7 Mpa and compressive strengths of 3.6 MPa. The Rohacell foams cannot withstand liquid hydrogen temperatures, however Imi-Tech markets Solimide (trademark) foams which withstand temperatures from -250 C to 200 C, but they do not have the required structural integrity. The research activity at NASA Langley Research Center focuses on using chemical blowing agents to produce polyimide thermoplastic foams capable of meeting the above performance requirements. The combination of blowing agents that decompose at the minimum melt viscosity temperature together with plasticizers to lower the viscosity has been used to produce foams by both extrusion and oven heating. The foams produced exhibit good environmental stability while maintaining structural properties.

  6. The Structure of Phenylglycinol

    NASA Astrophysics Data System (ADS)

    Simao, Alcides; Peña, Isabel; Cabezas, Carlos; Alonso, José L.

    2014-06-01

    The most abundant conformer of the amino alcohol D-phenylglycinol has been observed in gas phase using broadband chirped pulse Fourier transform microwave spectroscopy (CP-FTMW) and laser ablation molecular beam Fourier transform microwave spectroscopy (LA-MB-FTMW). The rotational spectra corresponding to seven monosubstituted 13C, one monosubstituted 15N and one monosubstituted 18O species have been observed in their natural abundance, and the rs structure has been derived. The observed conformer is stabilized by O-H\\cdotsN, N-H\\cdotsπ intramolecular hydrogen bond network.

  7. Concrete Materials and Structures

    SciTech Connect

    Wilby, C.B.

    1991-12-31

    Concrete Materials and Structures provides one of the most comprehensive treatments on the topic of concrete engineering. The author covers a gamut of concrete subjects ranging from concrete mix design, basic reinforced concrete theory, prestressed concrete, shell roofs, and two-way slabs-including a through presentation of Hillerborg`s strip method. Prior to Wilby`s book, the scope of these topics would require at least four separate books to cover. With this new book he has succeeded, quite remarkably, in condensing a fairly complete knowledge of concrete engineering into one single easy-to-carry volume.

  8. Other Fabric Structures

    NASA Technical Reports Server (NTRS)

    1985-01-01

    There are two kinds of fabric structures - tension, supported by cables and pylons, and those supported by air pressure within an enclosed fabric envelope. They are becoming increasingly popular with architects, engineers, etc., because of their aesthetic appeal, low cost and maintenance, energy efficiency and good space utilization. The Structo-Fab roof weighs only 1/30 as much as a conventional roof of that size. Giant fans are used to blow air into the envelope between the roof's outer membrane and its inner liner automatically maintaining the pressure differential necessary for roof rigidity.

  9. Work breakdown structure guide

    SciTech Connect

    Not Available

    1987-02-06

    Utilization of the work breakdown structure (WBS) technique is an effective aid in managing Department of Energy (DOE) programs and projects. The technique provides a framework for project management by focusing on the products that are being developed or constructed to solve technical problems. It assists both DOE and contractors in fulfilling their management responsibilities. This document provides guidance for use of the WBS technique for product oriented work identification and definition. It is one in a series of policy and guidance documents supporting DOE's project manaagement system.

  10. Structural integrity in aircraft.

    NASA Technical Reports Server (NTRS)

    Hardrath, H. F.

    1973-01-01

    The paper reviews briefly the current design philosophies for achieving long, efficient, and reliable service in aircraft structures. The strengths and weaknesses of these design philosophies and their demonstrated records of success are discussed. The state of the art has not been developed to the point where designing can be done without major test inspection and maintenance programs. A broad program of research is proposed through which a viable computerized design scheme will be provided during the next decade. The program will organize and correlate existing knowledge on fatigue and fracture behavior, identify gaps in this knowledge, and guide specific research to upgrade design capabilities.

  11. Modeling solar magnetic structures

    NASA Technical Reports Server (NTRS)

    Low, B. C.

    1985-01-01

    Some ideas in the theoretical study of force-free magnetic fields and magnetostatic fields, which are relevant to the effort of using magnetograph data as inputs to model the quasi-static, large-scale magnetic structures in the solar atmosphere are discussed. Basic physical principles will be emphasized. An attempt will be made to assess what we may learn, physically, from the models based on these ideas. There is prospect for learning useful physics and this ought to be an incentive for intensifying the efforts to improve vector magnetograph technology and to solve the basic radiative-transfer problems encountered in the interpretation of magnetograph raw data.

  12. Composite Structural Materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberly, S. E.

    1984-01-01

    The development and application of filamentary composite materials, is considered. Such interest is based on the possibility of using relatively brittle materials with high modulus, high strength, but low density in composites with good durability and high tolerance to damage. Fiber reinforced composite materials of this kind offer substantially improved performance and potentially lower costs for aerospace hardware. Much progress has been made since the initial developments in the mid 1960's. There were only limited applied to the primary structure of operational vehicles, mainly as aircrafts.

  13. Structure of Viral Aggregates

    NASA Astrophysics Data System (ADS)

    Barr, Stephen; Luijten, Erik

    2010-03-01

    The aggregation of virus particles is a particular form of colloidal self-assembly, since viruses of a give type are monodisperse and have identical, anisotropic surface charge distributions. In small-angle X-ray scattering experiments, the Qbeta virus was found to organize in different crystal structures in the presence of divalent salt and non-adsorbing polymer. Since a simple isotropic potential cannot explain the occurrence of all observed phases, we employ computer simulations to investigate how the surface charge distribution affects the virus interactions. Using a detailed model of the virus particle, we find an asymmetric ion distribution around the virus which gives rise to the different phases observed.

  14. Large space structures testing

    NASA Technical Reports Server (NTRS)

    Waites, Henry; Worley, H. Eugene

    1987-01-01

    There is considerable interest in the development of testing concepts and facilities that accurately simulate the pathologies believed to exist in future spacecraft. Both the Government and Industry have participated in the development of facilites over the past several years. The progress and problems associated with the development of the Large Space Structure Test Facility at the Marshall Flight Center are presented. This facility was in existence for a number of years and its utilization has run the gamut from total in-house involvement, third party contractor testing, to the mutual participation of other Government Agencies in joint endeavors.

  15. Structural Analogues of Selfotel.

    PubMed

    Dziuganowska, Zofia A; Ślepokura, Katarzyna; Volle, Jean-Noël; Virieux, David; Pirat, Jean-Luc; Kafarski, Paweł

    2016-06-17

    A small library of phosphonopiperidylcarboxylic acids, analogues of NMDA antagonist selfotel (CGS 19755), was synthesized. First, the series of aromatic esters was obtained via a palladium-catalyzed cross-coupling reaction (Hirao coupling) of dialkyl phosphites with bromopyridinecarboxylates, followed by their hydrolysis. Then, hydrogenation of the resulting phosphonopyridylcarboxylic acids over PtO2 yielded the desired phosphonopiperidylcarboxylic acids. NMR studies indicated that the hydrogenation reaction proceeds predominantly by cis addition. Several compounds were obtained as monocrystal structures. Preliminary biological studies performed on cultures of neurons suggest that the obtained compounds possess promising activity toward NMDA receptors. PMID:27187758

  16. Structured light camera calibration

    NASA Astrophysics Data System (ADS)

    Garbat, P.; Skarbek, W.; Tomaszewski, M.

    2013-03-01

    Structured light camera which is being designed with the joined effort of Institute of Radioelectronics and Institute of Optoelectronics (both being large units of the Warsaw University of Technology within the Faculty of Electronics and Information Technology) combines various hardware and software contemporary technologies. In hardware it is integration of a high speed stripe projector and a stripe camera together with a standard high definition video camera. In software it is supported by sophisticated calibration techniques which enable development of advanced application such as real time 3D viewer of moving objects with the free viewpoint or 3D modeller for still objects.

  17. Twisted waveguide accelerating structure.

    SciTech Connect

    Kang, Y. W.

    2000-08-15

    A hollow waveguide with a uniform cross section may be used for accelerating charged particles if the phase velocity of an accelerating mode is equal to or less than the free space speed of light. Regular straight hollow waveguides have phase velocities of propagating electromagnetic waves greater than the free-space speed of light. if the waveguide is twisted, the phase velocities of the waveguide modes become slower. The twisted waveguide structure has been modeled and computer simulated in 3-D electromagnetic solvers to show the slow-wave properties for the accelerating mode.

  18. Wind Turbine Structural Dynamics

    NASA Technical Reports Server (NTRS)

    Miller, D. R. (Editor)

    1978-01-01

    A workshop on wind turbine structural dynamics was held to review and document current United States work on the dynamic behavior of large wind turbines, primarily of the horizontal-axis type, and to identify and discuss other wind turbine configurations that may have lower cost and weight. Information was exchanged on the following topics: (1) Methods for calculating dynamic loads; (2) Aeroelasticity stability (3) Wind loads, both steady and transient; (4) Critical design conditions; (5) Drive train dynamics; and (6) Behavior of operating wind turbines.

  19. Mars Life? - Microscopic Structures

    NASA Technical Reports Server (NTRS)

    1996-01-01

    In the center of this electron microscope image of a small chip from a meteorite are several tiny structures that are possible microscopic fossils of primitive, bacteria-like organisms that may have lived on Mars more than 3.6 billion years ago. A two-year investigation by a NASA research team found organic molecules, mineral features characteristic of biological activity and possible microscopic fossils such as these inside of an ancient Martian rock that fell to Earth as a meteorite. The largest possible fossils are less than 1/100th the diameter of a human hair in size while most are ten times smaller.

  20. Magnetic microhelix coil structures.

    PubMed

    Smith, Elliot J; Makarov, Denys; Sanchez, Samuel; Fomin, Vladimir M; Schmidt, Oliver G

    2011-08-26

    Together with the well-known ferro- and antiferromagnetic ordering, nature has created a variety of complex helical magnetic configurations. Here, we design and investigate three-dimensional microhelix coil structures that are radial-, corkscrew-, and hollow-bar-magnetized. The magnetization configurations of the differently magnetized coils are experimentally revealed by probing their specific dynamic response to an external magnetic field. Helix coils offer an opportunity to realize microscale geometries of the magnetic toroidal moment, observed so far only in bulk multiferroic materials. PMID:21929266

  1. Magnetic Microhelix Coil Structures

    NASA Astrophysics Data System (ADS)

    Smith, Elliot J.; Makarov, Denys; Sanchez, Samuel; Fomin, Vladimir M.; Schmidt, Oliver G.

    2011-08-01

    Together with the well-known ferro- and antiferromagnetic ordering, nature has created a variety of complex helical magnetic configurations. Here, we design and investigate three-dimensional microhelix coil structures that are radial-, corkscrew-, and hollow-bar-magnetized. The magnetization configurations of the differently magnetized coils are experimentally revealed by probing their specific dynamic response to an external magnetic field. Helix coils offer an opportunity to realize microscale geometries of the magnetic toroidal moment, observed so far only in bulk multiferroic materials.

  2. Structured Multifrontal Sparse Solver

    Energy Science and Technology Software Center (ESTSC)

    2014-05-01

    StruMF is an algebraic structured preconditioner for the interative solution of large sparse linear systems. The preconditioner corresponds to a multifrontal variant of sparse LU factorization in which some dense blocks of the factors are approximated with low-rank matrices. It is algebraic in that it only requires the linear system itself, and the approximation threshold that determines the accuracy of individual low-rank approximations. Favourable rank properties are obtained using a block partitioning which is amore » refinement of the partitioning induced by nested dissection ordering.« less

  3. Piezoelectric Sensor Evaluation for Structural Health Monitoring of Cryogenic Structures

    NASA Technical Reports Server (NTRS)

    Lassiter, John; Engberg, Robert

    2005-01-01

    This viewgraph presentation provides an overview of Structural Health Monitoring (SHM), and profiles piezoelectric sensors useful for SHM of cryogenic structures. The presentation also profiles impedance tests and other SHM tests conducted at Marshall Space Flight Center (MSFC).

  4. Probabilistic structural analysis methods of hot engine structures

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Hopkins, D. A.

    1989-01-01

    Development of probabilistic structural analysis methods for hot engine structures at Lewis Research Center is presented. Three elements of the research program are: (1) composite load spectra methodology; (2) probabilistic structural analysis methodology; and (3) probabilistic structural analysis application. Recent progress includes: (1) quantification of the effects of uncertainties for several variables on high pressure fuel turbopump (HPFT) turbine blade temperature, pressure, and torque of the space shuttle main engine (SSME); (2) the evaluation of the cumulative distribution function for various structural response variables based on assumed uncertainties in primitive structural variables; and (3) evaluation of the failure probability. Collectively, the results demonstrate that the structural durability of hot engine structural components can be effectively evaluated in a formal probabilistic/reliability framework.

  5. View facing northeast of Structure 1034, last numbered structure on ...

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

    View facing northeast of Structure 103-4, last numbered structure on northern (Havre) end of Transmission Line - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  6. Research in structures, structural dynamics and materials, 1989

    NASA Technical Reports Server (NTRS)

    Hunter, William F. (Compiler); Noor, Ahmed K. (Compiler)

    1989-01-01

    Topics addressed include: composite plates; buckling predictions; missile launch tube modeling; structural/control systems design; optimization of nonlinear R/C frames; error analysis for semi-analytic displacement; crack acoustic emission; and structural dynamics.

  7. Structural alphabets for protein structure classification: a comparison study.

    PubMed

    Le, Quan; Pollastri, Gianluca; Koehl, Patrice

    2009-03-27

    Finding structural similarities between proteins often helps reveal shared functionality, which otherwise might not be detected by native sequence information alone. Such similarity is usually detected and quantified by protein structure alignment. Determining the optimal alignment between two protein structures, however, remains a hard problem. An alternative approach is to approximate each three-dimensional protein structure using a sequence of motifs derived from a structural alphabet. Using this approach, structure comparison is performed by comparing the corresponding motif sequences or structural sequences. In this article, we measure the performance of such alphabets in the context of the protein structure classification problem. We consider both local and global structural sequences. Each letter of a local structural sequence corresponds to the best matching fragment to the corresponding local segment of the protein structure. The global structural sequence is designed to generate the best possible complete chain that matches the full protein structure. We use an alphabet of 20 letters, corresponding to a library of 20 motifs or protein fragments having four residues. We show that the global structural sequences approximate well the native structures of proteins, with an average coordinate root mean square of 0.69 A over 2225 test proteins. The approximation is best for all alpha-proteins, while relatively poorer for all beta-proteins. We then test the performance of four different sequence representations of proteins (their native sequence, the sequence of their secondary-structure elements, and the local and global structural sequences based on our fragment library) with different classifiers in their ability to classify proteins that belong to five distinct folds of CATH. Without surprise, the primary sequence alone performs poorly as a structure classifier. We show that addition of either secondary-structure information or local information from the

  8. Probabilistic Design of Composite Structures

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    2006-01-01

    A formal procedure for the probabilistic design evaluation of a composite structure is described. The uncertainties in all aspects of a composite structure (constituent material properties, fabrication variables, structural geometry, and service environments, etc.), which result in the uncertain behavior in the composite structural responses, are included in the evaluation. The probabilistic evaluation consists of: (1) design criteria, (2) modeling of composite structures and uncertainties, (3) simulation methods, and (4) the decision-making process. A sample case is presented to illustrate the formal procedure and to demonstrate that composite structural designs can be probabilistically evaluated with accuracy and efficiency.

  9. Analytical ultrasonics for structural materials

    NASA Technical Reports Server (NTRS)

    Kupperman, D. S.

    1986-01-01

    The application of ultrasonic velocity and attenuation measurements to characterize the microstructure of structural materials is discussed. Velocity measurements in cast stainless steel are correlated with microstructural variations ranging from equiaxed (elastically isotropic) to columnar (elastically anisotropic) grain structure. The effect of the anisotropic grain structure on the deviation of ultrasonic waves in cast stainless steel is also reported. Field-implementable techniques for distinguishing equiaxed from columnar grain structures in cast strainless steel structural members are presented. The application of ultrasonic velocity measurements to characterize structural ceramics in the green state is also discussed.

  10. Structured wafer for device processing

    SciTech Connect

    Okandan, Murat; Nielson, Gregory N

    2014-05-20

    A structured wafer that includes through passages is used for device processing. Each of the through passages extends from or along one surface of the structured wafer and forms a pattern on a top surface area of the structured wafer. The top surface of the structured wafer is bonded to a device layer via a release layer. Devices are processed on the device layer, and are released from the structured wafer using etchant. The through passages within the structured wafer allow the etchant to access the release layer to thereby remove the release layer.

  11. Structured wafer for device processing

    SciTech Connect

    Okandan, Murat; Nielson, Gregory N

    2014-11-25

    A structured wafer that includes through passages is used for device processing. Each of the through passages extends from or along one surface of the structured wafer and forms a pattern on a top surface area of the structured wafer. The top surface of the structured wafer is bonded to a device layer via a release layer. Devices are processed on the device layer, and are released from the structured wafer using etchant. The through passages within the structured wafer allow the etchant to access the release layer to thereby remove the release layer.

  12. Structural Pain Compensating Flight Control

    NASA Technical Reports Server (NTRS)

    Miller, Chris J.

    2014-01-01

    The problem of control command and maneuver induced structural loads is an important aspect of any control system design. Designers must design the aircraft structure and the control architecture to achieve desired piloted control responses while limiting the imparted structural loads. The classical approach is to build the structure with high margins, restrict control surface commands to known good combinations, and train pilots to follow procedural maneuvering limitations. With recent advances in structural sensing and the continued desire to improve safety and vehicle fuel efficiency, it is both possible and desirable to develop control architectures that enable lighter vehicle weights while maintaining and improving protection against structural damage.

  13. Probabilistic structural analysis methods of hot engine structures

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Hopkins, D. A.

    1989-01-01

    Development of probabilistic structural analysis methods for hot engine structures is a major activity at Lewis Research Center. Recent activities have focused on extending the methods to include the combined uncertainties in several factors on structural response. This paper briefly describes recent progress on composite load spectra models, probabilistic finite element structural analysis, and probabilistic strength degradation modeling. Progress is described in terms of fundamental concepts, computer code development, and representative numerical results.

  14. Ground test validation of large precision structure through adaptive structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.

    1992-01-01

    Without novel ground validation test (GVT) approaches for such space structures as those contemplated for an orbiting optical interferometer, this and other NASA missions will be stillborn. One such approach may involve the integration of adaptive structures concepts into initial structural designs, in order to accommodate GVT, as well as to allow for redundancy and enhance mission reliability. Adaptive structures are noted to intrinsically relax GVT requirements.

  15. Structural Analysis of Biodiversity

    PubMed Central

    Sirovich, Lawrence; Stoeckle, Mark Y.; Zhang, Yu

    2010-01-01

    Large, recently-available genomic databases cover a wide range of life forms, suggesting opportunity for insights into genetic structure of biodiversity. In this study we refine our recently-described technique using indicator vectors to analyze and visualize nucleotide sequences. The indicator vector approach generates correlation matrices, dubbed Klee diagrams, which represent a novel way of assembling and viewing large genomic datasets. To explore its potential utility, here we apply the improved algorithm to a collection of almost 17000 DNA barcode sequences covering 12 widely-separated animal taxa, demonstrating that indicator vectors for classification gave correct assignment in all 11000 test cases. Indicator vector analysis revealed discontinuities corresponding to species- and higher-level taxonomic divisions, suggesting an efficient approach to classification of organisms from poorly-studied groups. As compared to standard distance metrics, indicator vectors preserve diagnostic character probabilities, enable automated classification of test sequences, and generate high-information density single-page displays. These results support application of indicator vectors for comparative analysis of large nucleotide data sets and raise prospect of gaining insight into broad-scale patterns in the genetic structure of biodiversity. PMID:20195371

  16. Structural Colors of Birds

    NASA Astrophysics Data System (ADS)

    Hall, Cecilia; Dushkina, Natalia

    2016-03-01

    Structural colors create iridescent colors in bird feathers. The goal is to understand why structural colors act the way they do in certain situations. The research conducted over the course of the fall semester was to understand the optical phenomenon producing colors in individual barbules. Through the use of a polarizing optical microscope, certain hypotheses were built to explain certain phenomenon. Using a dark field illumination involving light acting at wide angles in microscopy, the barbules were not affected by polarization. So it can be suggested that the barbules have certain characteristics, possibly internal, which prevents wide-angle polarization. More recently, it was found that the barbules, when stacked upon one another, create a discoloration at the cross over point. It can be suggested that the barbules act as thin films and create a situation of thin film interference. More data will be taken using the Scanning Electron Microscope as well as getting cross sectional data to help understand the internal characteristics of the barbules. From the support of the Neimeyer-Hodgson Grant, Chris Stull, and Millersville University of Pennsylvania.

  17. Feed Structure For Antennas

    NASA Technical Reports Server (NTRS)

    Fink, Patrick W. (Inventor); Chu, Andrew W. (Inventor); Dobbins, Justin A. (Inventor); Lin, Greg Y. (Inventor)

    2005-01-01

    A novel feed structure, for an antenna having a resonant electric field structure, comprising a patch element, an integrated circuit attached to the patch element, at least one inner conductor electrically connected to and terminating at the integrated circuit on a first end of the at least one inner conductor, wherein the at least one inner conductor extends through and is not electrically connected to the patch element, and wherein the at least one inner conductor is available for electrical connectivity on a second end of the at least one inner conductor, and an outer conductor electrically connected to and terminating at the patch element on a first end of the outer conductor, wherein the outer conductor is available for electrical connectivity on a second end of the outer conductor, and wherein the outer conductor concentrically surrounds the at least one inner conductor from the second end of the at least one inner conductor available for electrical connectivity to the first end of the outer conductor terminating at the patch element.

  18. DNA structure and function.

    PubMed

    Travers, Andrew; Muskhelishvili, Georgi

    2015-06-01

    The proposal of a double-helical structure for DNA over 60 years ago provided an eminently satisfying explanation for the heritability of genetic information. But why is DNA, and not RNA, now the dominant biological information store? We argue that, in addition to its coding function, the ability of DNA, unlike RNA, to adopt a B-DNA structure confers advantages both for information accessibility and for packaging. The information encoded by DNA is both digital - the precise base specifying, for example, amino acid sequences - and analogue. The latter determines the sequence-dependent physicochemical properties of DNA, for example, its stiffness and susceptibility to strand separation. Most importantly, DNA chirality enables the formation of supercoiling under torsional stress. We review recent evidence suggesting that DNA supercoiling, particularly that generated by DNA translocases, is a major driver of gene regulation and patterns of chromosomal gene organization, and in its guise as a promoter of DNA packaging enables DNA to act as an energy store to facilitate the passage of translocating enzymes such as RNA polymerase. PMID:25903461

  19. Milky Way's Structure: Theory

    NASA Astrophysics Data System (ADS)

    Bartlett, D. F.

    2005-12-01

    The cover of the August issue of the Astronomical Journal is stunningly simple. The basic structure of the Milky Way appears as a central bar surrounded by four evenly-spaced logarithmic spirals. (Vallée 2005). Modern density wave theory can accommodate such spirals, but only by using arbitrary functions of time (Bertin 2000). Perhaps the problem is Newton's gravitational law itself. With or without dark matter, this law allows the potential to have only two kinds of extrema: dimples and saddle points. In contrast, the proposed sinusoidal potential also permits potential maxima or pimples. (In the sinusoidal potential φ (r)=-(GM/r) cos(ko r) where ko = 2 π /λ o and the universal 'wavelength' λ o is 425 pc (Bartlett 2004). I will show how the sinusoidal potential permits the spiral structure of the Galaxy to be stable. Deep ridges in the radial direction confine stars to circular orbits. A broad potential maximum in the z-direction suppresses the normally deep minimum at z=0 caused by matter in the local disk. Alternating minima and maxima in the φ -direction give spirals that are keyed to the central bar.

  20. Prominence Structure and Dynamics

    NASA Technical Reports Server (NTRS)

    Karpen, Judy T.

    2009-01-01

    Nonerupting prominences are not dull, static objects. Rather, they are composed of fine-scale blobs and threads that are highly dynamic, often appearing to travel in opposite directions on adjacent tracks (denoted counterstreaming). Because the plasma is largely constrained to travel along the magnetic field, these cool, dense features can serve as tracers of the prominence magnetic structure, a valuable resource in view of the long-standing difficulty of observing the coronal field. Conversely, greater understanding of the fundamental magnetic geometry of filament channels can provide important constraints on the physical processes governing the accumulation, support, motion, and eruption of the cool plasma. Despite over a century of detailed observations, large gaps remain in our knowledge of filament channel/plasma formation and evolution. Resolving these issues will shed light on the physics of coronal heating, helicity transport throughout the solar cycle, and the origins of eruptive activity on the Sun. I will discuss the leading models for the magnetic and plasma structure, and outline how new observations and theory /modeling could solve long-standing uncertainties regarding this majestic solar phenomenon.

  1. Solar Sector Structure

    NASA Astrophysics Data System (ADS)

    Hudson, Hugh S.; Svalgaard, Leif; Hannah, Iain G.

    2014-12-01

    The interplanetary magnetic field near 1 AU has a characteristic "sector" structure that reflects its polarity relative to the solar direction. Typically we observe large-scale coherence in these directions, with two or four "away" or "towards" sectors per solar rotation, from any platform in deep space and near the ecliptic plane. In a simple picture, this morphology simply reflects the idea that the sources of the interplanetary field lie mainly in or near the Sun, and that the solar-wind flow enforces a radial component in this field. The sector boundaries are sharply defined in the interplanetary field near one AU, but have more complicated sources within the Sun itself. Recent evidence confirms that the origins of this pattern also appear statistically at the level of the photosphere, with signatures found in the highly concentrated fields of sunspots and even solar flares. This complements the associations already known between the interplanetary sectors and large-scale coronal structures (i.e., the streamers). This association with small-scale fields strengthens at the Hale sector boundary, defining the Hale boundary as the one for which the polarity switch matches that of the leading-to-following polarity alternation in the sunspots of a given hemisphere. Surface features that appear 4.5 days prior to the sector crossings observed at 1 AU correlate with this sense of polarity reversal.

  2. Lagrange structure and quantization

    NASA Astrophysics Data System (ADS)

    Kazinski, Peter O.; Lyakhovich, Simon L.; Sharapov, Alexey A.

    2005-07-01

    A path-integral quantization method is proposed for dynamical systems whose classical equations of motion do not necessarily follow from the action principle. The key new notion behind this quantization scheme is the Lagrange structure which is more general than the lagrangian formalism in the same sense as Poisson geometry is more general than the symplectic one. The Lagrange structure is shown to admit a natural BRST description which is used to construct an AKSZ-type topological sigma-model. The dynamics of this sigma-model in d+1 dimensions, being localized on the boundary, are proved to be equivalent to the original theory in d dimensions. As the topological sigma-model has a well defined action, it is path-integral quantized in the usual way that results in quantization of the original (not necessarily lagrangian) theory. When the original equations of motion come from the action principle, the standard BV path-integral is explicitly deduced from the proposed quantization scheme. The general quantization scheme is exemplified by several models including the ones whose classical dynamics are not variational.

  3. Silk structure and degradation.

    PubMed

    Liu, Bin; Song, Yu-wei; Jin, Li; Wang, Zhi-jian; Pu, De-yong; Lin, Shao-qiang; Zhou, Chan; You, Hua-jian; Ma, Yan; Li, Jin-min; Yang, Li; Sung, K L Paul; Zhang, Yao-guang

    2015-07-01

    To investigate the structure of silk and its degradation properties, we have monitored the structure of silk using scanning electron microscopy and frozen sections. Raw silk and degummed raw silk were immersed in four types of degradation solutions for 156 d to observe their degradation properties. The subcutaneous implants in rats were removed after 7, 14, 56, 84, 129, and 145 d for frozen sectioning and subsequent staining with hematoxylin and eosin (H.E.), DAPI, Beta-actin and Collagen I immunofluorescence staining. The in vitro weight loss ratio of raw silk and degummed raw silk in water, PBS, DMEM and DMEM containing 10% FBS (F-DMEM) were, respectively, 14%/11%, 12.5%/12.9%, 11.1%/14.3%, 8.8%/11.6%. Silk began to degrade after 7 d subcutaneous implantation and after 145 d non-degraded silk was still observed. These findings suggest the immunogenicity of fibroin and sericin had no essential difference. In the process of in vitro degradation of silk, the role of the enzyme is not significant. The in vivo degradation of silk is related to phagocytotic activity and fibroblasts may be involved in this process to secrete collagen. This study also shows the developing process of cocoons and raw silk. PMID:25982316

  4. Thermodynamics. [algebraic structure

    NASA Technical Reports Server (NTRS)

    Zeleznik, F. J.

    1976-01-01

    The fundamental structure of thermodynamics is purely algebraic, in the sense of atopological, and it is also independent of partitions, composite systems, the zeroth law, and entropy. The algebraic structure requires the notion of heat, but not the first law. It contains a precise definition of entropy and identifies it as a purely mathematical concept. It also permits the construction of an entropy function from heat measurements alone when appropriate conditions are satisfied. Topology is required only for a discussion of the continuity of thermodynamic properties, and then the weak topology is the relevant topology. The integrability of the differential form of the first law can be examined independently of Caratheodory's theorem and his inaccessibility axiom. Criteria are established by which one can determine when an integrating factor can be made intensive and the pseudopotential extensive and also an entropy. Finally, a realization of the first law is constructed which is suitable for all systems whether they are solids or fluids, whether they do or do not exhibit chemical reactions, and whether electromagnetic fields are or are not present.

  5. 161. North Carolina Route 80 grade separation structure. The structure ...

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

    161. North Carolina Route 80 grade separation structure. The structure at Buck Creek Gap, built in 1942, has a clear span of 139. Both the roadway running atop and under the structure have a curving alignment. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  6. Classification & Structure of Blood Vessels

    MedlinePlus

    ... Cells, Tissues, & Membranes Cell Structure & Function Cell Structure Cell Function Body Tissues Epithelial Tissue Connective Tissue Muscle Tissue ... return blood to the heart (veins). The primary function of capillaries is the ... cells. Capillary distribution varies with the metabolic activity of ...

  7. MODE: Structural Test Article (STA)

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Masters, Brett

    1992-01-01

    Viewgraphs on the Middeck 0-gravity Dynamics Experiment (MODE): Structural Test Article (STA) are presented. Topics covered include: MODE: structural test article motivation; hardware; sensors and actuators; experimental support module; data; preliminary results; supporting analysis program; and modeling approach.

  8. Vibration suppression using smart structures

    NASA Technical Reports Server (NTRS)

    Garcia, Ephrahim; Inman, Daniel J.; Dosch, Jeffrey

    1991-01-01

    The control of structures for vibration suppression is discussed in the context of using smart materials and structures. Here the use of smart structures refers to using embedded piezoelectric devices as both control actuators and sensors. Using embedded sensors and actuators allows great improvements in performance over traditional structures (both passive and active) for vibration suppression. The application of smart structures to three experimental flexible structures is presented. The first is a flexible beam, the second is a flexible beam undergoing slewing motion, the third is a ribbed antenna. A simple model of a piezoelectric actuator/sensor is presented. The equations of motion for each structure is presented. The control issues considered as those associated with multi-input, multi-output control, PID control and LQR control implementation. A modern control analysis illustrates the usefulness of smart structures for vibration suppression.

  9. Sub-structures in hadrons and proton structure functions

    NASA Astrophysics Data System (ADS)

    Arash, Firooz; Khorramian, Ali N.

    2001-04-01

    We calculate the partonic structure of constituent quark in the Next-to-Leading Order. Using a convolution method, Structure function of proton is presented. While the constituent quark structure is generated purely perturbatively and accounts for the most part of the hadronic structure, there is a few percent contributions coming from the nonperturbative sector in the hadronic structure. This contribution plays the key role in explaining the SU(2) symmetry breaking of the nucleon sea and the observed violation of Gottfried sum rule. Excellent agreement with data in a wide range of x = [10 -6, 1] and Q2 = [0.5, 5000] GeV2 for Fp2 is reached.

  10. Structural Assembly Demonstration Experiment (SADE)

    NASA Technical Reports Server (NTRS)

    Akin, David L.; Mills, Raymond A.; Bowden, Mary L.

    1987-01-01

    The purpose of the Structural Assembly Demonstration Experiment (SADE) was to create a near-term Shuttle flight experiment focusing on the deployment and erection of structural truss elements. The activities of the MIT Space Systems Laboratory consist of three major areas: preparing and conducting neutral buoyancy simulation test series; producing a formal SADE Experiment plan; and studying the structural dynamics issues of the truss structure. Each of these areas is summarized.

  11. Jiram' s Data Structure

    NASA Astrophysics Data System (ADS)

    Noschese, Raffaella; Adriani, Alberto; Tosi, Federico; Moriconi, Maria Luisa; Filacchione, Gianrico; Cicchetti, Andrea; Mura, Alessandro

    JIRAM is a spectro-imager onboard the Juno spacecraft, which is due to enter a polar orbit around Jupiter in July 2016. JIRAM combines two separate channels: an IR imager and a spectrometer in the 2-5 µm range. The main scientific goals of JIRAM are the study of the Jovian aurorae and of the planet's atmospheric structure, dynamics and composition. The present work provides the JIRAM user with a detailed description of the data products and how they are generated, including information about data sources and destinations. We describe the data flow of the JIRAM instrument from the S/C to the Juno Science Operation Center (JSOC). This includes information on how data are processed, formatted, labeled and uniquely identified.

  12. Electromagnetic structure of pion

    SciTech Connect

    Mello, Clayton S.; Cruz Filho, Jose P.; Da Silva, Edson O.; El-Bennich, Bruno; De Melo, J. P.; Filho, Victo S.

    2013-03-25

    In this work, we analyze the electromagnetic structure of the pion, an elementary particle composed by a quark-antiquark bound state, by considering the calculation of its electromagnetic radius and its electromagnetic form factor in low and intermediate energy range. Such observables are determined by means of a theoretical model that takes into account the constituent quark and antiquark of the pion, in the formalism of the light-front field theory. In particular, it is considered a nonsymmetrical vertex for such a model, in which we have calculated the electromagnetic form factor of the pion in an optimized way, by varying its regulator mass, so that we can obtain the best value for the pion electromagnetic radius when compared with the experimental one. The theoretical calculations are also compared with the most recent experimental data involving the pion electromagnetic form factor and the results show very good agreement.

  13. Allergen structures and epitopes.

    PubMed

    Meno, K H

    2011-07-01

    Human type 1 hypersensitivity diseases such as allergic rhinoconjunctivitis are characterized by allergen-specific IgE antibodies produced in allergic individuals after allergen exposure. IgE antibodies bound to receptors on the surface of effector cells trigger an allergic response by interacting with three-dimensional (conformational) epitopes on the allergen surface. Crystal structures are available for complexes of antibody specifically bound to five allergens, from birch pollen, bee venom, cockroach, cow's milk and timothy grass pollen. The details of the antibody-allergen interaction extending all the way to atomic resolution are available from such complexes. In vitro investigations using recombinant monoclonal antibodies and human basophils show that binding affinity is a key to triggering the allergic response. Continued molecular characterization of antibody-allergen interactions is paving the way for the use of recombinant allergens in allergen-specific diagnosis and immunotherapy. PMID:21668845

  14. High temperature structural silicides

    SciTech Connect

    Petrovic, J.J.

    1997-03-01

    Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi{sub 2}-based materials, which are borderline ceramic-intermetallic compounds. MoSi{sub 2} single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi{sub 2} possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi{sub 2}-Si{sub 3}N{sub 4} composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi{sub 2}-based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing.

  15. Activities report in structures

    NASA Astrophysics Data System (ADS)

    1986-10-01

    A stiffened plate macro-element; a macro-element of elastic pipe filled with liquid; modeling of the structural fuzzy in medium frequency computations; unsteady aerodynamic forces on jet engine air intakes; prediction of buffeting vibrations from unsteady pressure measurements taken in a wind tunnel; aeroelastic behavior of fan blades in the unstarted supersonic domain; wind tunnel study of a helicopter blade stall control; computer-controlled generator of turbulence in a wind tunnel; atmospheric turbulence statistics; adaptation of Neuber's theory to viscoplastic stress concentration; computation of a jet engine disk/flange assembly; and analysis of the damage done to a perforated composite plate under biaxial monotonic and cyclic loading are described.

  16. Picture Wall (Glass Structures)

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Photo shows a subway station in Toronto, Ontario, which is entirely glass-enclosed. The all-glass structure was made possible by a unique glazing concept developed by PPG Industries, Pittsburgh, Pennsylvania, one of the largest U.S. manufacturers of flat glass. In the TVS glazing system, transparent glass "fins" replace conventional vertical support members used to provide support for wind load resistance. For stiffening, silicone sealant bonds the fins to adjacent glass panels. At its glass research center near Pittsburgh, PPG Industries uses the NASTRAN computer program to analyze the stability of enclosures made entirely of glass. The company also uses NASTRAN to simulate stresses on large containers of molten glass and to analyze stress effects of solar heating on flat glass.

  17. Aluminum structural applications

    SciTech Connect

    Lucas, G.

    1996-05-01

    Extensive research by aluminum producers and automakers in the 1980s resulted in the development of technologies that enable building of aluminum cars that meet and exceed all the expectations of today`s drivers and passengers, yet weigh several hundred pounds less than their steel counterparts. The Acura NSX sports car, the Audi A8, and the Jaguar XJ220 have all been introduced. Ford has built 40 aluminum-intensive automobiles based on the Taurus/Sable for test purposes, and General Motors recently announced an aluminum-structured electric vehicle. The design flexibility that aluminum allows is shown by these examples. Each uses a somewhat different technology that is particularly suited to the vehicle and its market.

  18. Structural color in Myxomycetes.

    PubMed

    Inchaussandague, Marina; Skigin, Diana; Carmaran, Cecilia; Rosenfeldt, Sonia

    2010-07-19

    In this paper we report evidence of structural color in Myxomycetes, a group of eukaryotic microorganisms with an uncertain taxonomic position. We investigated the Diachea leucopoda, which belongs to the Physarales order, Myxomycetes class, and found that its peridium -protective layer that encloses the mass of spores- is basically a corrugated layer of a transparent material, which produces a multicolored pointillistic effect, characteristic of this species. Scanning (SEM) and transmission (TEM) electron microscopy techniques have been employed to characterize the samples. A simple optical model of a planar slab is proposed to calculate the reflectance. The chromaticity coordinates are obtained, and the results confirm that the color observed is a result of an interference effect. PMID:20720990

  19. Discovering hierarchical motion structure.

    PubMed

    Gershman, Samuel J; Tenenbaum, Joshua B; Jäkel, Frank

    2016-09-01

    Scenes filled with moving objects are often hierarchically organized: the motion of a migrating goose is nested within the flight pattern of its flock, the motion of a car is nested within the traffic pattern of other cars on the road, the motion of body parts are nested in the motion of the body. Humans perceive hierarchical structure even in stimuli with two or three moving dots. An influential theory of hierarchical motion perception holds that the visual system performs a "vector analysis" of moving objects, decomposing them into common and relative motions. However, this theory does not specify how to resolve ambiguity when a scene admits more than one vector analysis. We describe a Bayesian theory of vector analysis and show that it can account for classic results from dot motion experiments, as well as new experimental data. Our theory takes a step towards understanding how moving scenes are parsed into objects. PMID:25818905

  20. Parkin structure and function

    PubMed Central

    Seirafi, Marjan; Kozlov, Guennadi; Gehring, Kalle

    2015-01-01

    Mutations in the parkin or PINK1 genes are the leading cause of the autosomal recessive form of Parkinson’s disease. The gene products, the E3 ubiquitin ligase parkin and the serine/threonine kinase PINK1, are neuroprotective proteins, which act together in a mitochondrial quality control pathway. Here, we review the structure of parkin and mechanisms of its autoinhibition and function as a ubiquitin ligase. We present a model for the recruitment and activation of parkin as a key regulatory step in the clearance of depolarized or damaged mitochondria by autophagy (mitophagy). We conclude with a brief overview of other functions of parkin and considerations for drug discovery in the mitochondrial quality control pathway. PMID:25712550

  1. Fiber Accelerating Structures

    SciTech Connect

    Hammond, Andrew P.; /Reed Coll. /SLAC

    2010-08-25

    One of the options for future particle accelerators are photonic band gap (PBG) fiber accelerators. PBG fibers are specially designed optical fibers that use lasers to excite an electric field that is used to accelerate electrons. To improve PBG accelerators, the basic parameters of the fiber were tested to maximize defect size and acceleration. Using the program CUDOS, several accelerating modes were found that maximized these parameters for several wavelengths. The design of multiple defects, similar to having closely bound fibers, was studied to find possible coupling or the change of modes. The amount of coupling was found to be dependent on distance separated. For certain distances accelerating coupled modes were found and examined. In addition, several non-periodic fiber structures were examined using CUDOS. The non-periodic fibers produced several interesting results and promised more modes given time to study them in more detail.

  2. Transpressional Structures on Mercury

    NASA Astrophysics Data System (ADS)

    Massironi, M.; Di Achille, G.; Ferrari, S.; Giacomini, L.; Popa, C.; Pozzobon, R.; Zusi, M.; Cremonese, G.; Palumbo, P.

    2012-04-01

    Mercury is classically dominated by contractional features at a global scale (e.g. Watters et al.2009, EPSL]). Nonetheless, numerous evidences of strike-slip kinematics have been found on Mercury Dual Imaging System (MDIS) camera images mainly derived from the three MESSENGER flybys and acquired near the terminator. This proves that several lobate scarps and high-relief ridges may be interpreted as transpressional structures more than thrust and back-thrusts systems. This finding may support either tidal despinning or residual mantle convection on ruling the nucleation and development of lobate scarps, although within the general framework of planetary contraction and cooling. In addition, the presence of faults with a clear strike-slip kinematic component may possibly affect future estimates of the hermean radius shortening.

  3. Synchronously deployable truss structure

    NASA Technical Reports Server (NTRS)

    Bush, H. G. (Inventor); Mikulas, M., Jr. (Inventor); Wallsom, E. (Inventor)

    1986-01-01

    A collapsible-expandable truss structure, including first and second spaced surface truss layers having an attached core layer is described. The surface truss layers are composed of a plurality of linear struts arranged in multiple triangular configurations. Each linear strut is hinged at the center and hinge connected at each end to a nodular joint. A passive spring serves as the expansion force to move the folded struts from a stowed collapsed position to a deployed operative final truss configuration. A damper controls the rate of spring expansion for the synchronized deployment of the truss as the folded configuration is released for deployment by the restrain belts. The truss is synchronously extended under the control of motor driven spools.

  4. Parametric State Space Structuring

    NASA Technical Reports Server (NTRS)

    Ciardo, Gianfranco; Tilgner, Marco

    1997-01-01

    Structured approaches based on Kronecker operators for the description and solution of the infinitesimal generator of a continuous-time Markov chains are receiving increasing interest. However, their main advantage, a substantial reduction in the memory requirements during the numerical solution, comes at a price. Methods based on the "potential state space" allocate a probability vector that might be much larger than actually needed. Methods based on the "actual state space", instead, have an additional logarithmic overhead. We present an approach that realizes the advantages of both methods with none of their disadvantages, by partitioning the local state spaces of each submodel. We apply our results to a model of software rendezvous, and show how they reduce memory requirements while, at the same time, improving the efficiency of the computation.

  5. Riboswitches: Structures and Mechanisms

    PubMed Central

    Garst, Andrew D.; Edwards, Andrea L.; Batey, Robert T.

    2011-01-01

    SUMMARY A critical feature of the hypothesized RNA world would have been the ability to control chemical processes in response to environmental cues. Riboswitches present themselves as viable candidates for a sophisticated mechanism of regulatory control in RNA-based life. These regulatory elements in the modern world are most commonly found in the 5′-untranslated regions of bacterial mRNAs, directly interacting with metabolites as a means of regulating expression of the coding region via a secondary structural switch. In this review, we focus on recent insights into how these RNAs fold into complex architectures capable of both recognizing a specific small molecule compound and exerting regulatory control over downstream sequences, with an emphasis on transcriptional regulation. PMID:20943759

  6. Riboswitches: structures and mechanisms.

    PubMed

    Garst, Andrew D; Edwards, Andrea L; Batey, Robert T

    2011-06-01

    A critical feature of the hypothesized RNA world would have been the ability to control chemical processes in response to environmental cues. Riboswitches present themselves as viable candidates for a sophisticated mechanism of regulatory control in RNA-based life. These regulatory elements in the modern world are most commonly found in the 5'-untranslated regions of bacterial mRNAs, directly interacting with metabolites as a means of regulating expression of the coding region via a secondary structural switch. In this review, we focus on recent insights into how these RNAs fold into complex architectures capable of both recognizing a specific small molecule compound and exerting regulatory control over downstream sequences, with an emphasis on transcriptional regulation. PMID:20943759

  7. Dynamic Structural Health Monitoring of Slender Structures Using Optical Sensors

    PubMed Central

    Antunes, Paulo; Travanca, Rui; Rodrigues, Hugo; Melo, José; Jara, José; Varum, Humberto; André, Paulo

    2012-01-01

    In this paper we summarize the research activities at the Instituto de Telecomunicações—Pólo de Aveiro and University of Aveiro, in the field of fiber Bragg grating based sensors and their applications in dynamic measurements for Structural Health Monitoring of slender structures such as towers. In this work we describe the implementation of an optical biaxial accelerometer based on fiber Bragg gratings inscribed on optical fibers. The proof-of-concept was done with the dynamic monitoring of a reinforced concrete structure and a slender metallic telecommunication tower. Those structures were found to be suitable to demonstrate the feasibility of FBG accelerometers to obtain the structures' natural frequencies, which are the key parameters in Structural Health Monitoring and in the calibration of numerical models used to simulate the structure behavior. PMID:22778661

  8. CSM parallel structural methods research

    NASA Technical Reports Server (NTRS)

    Storaasli, Olaf O.

    1989-01-01

    Parallel structural methods, research team activities, advanced architecture computers for parallel computational structural mechanics (CSM) research, the FLEX/32 multicomputer, a parallel structural analyses testbed, blade-stiffened aluminum panel with a circular cutout and the dynamic characteristics of a 60 meter, 54-bay, 3-longeron deployable truss beam are among the topics discussed.

  9. Unraveling hepatitis C virus structure.

    PubMed

    Fauvelle, Catherine; Felmlee, Daniel J; Baumert, Thomas F

    2014-04-01

    The high variability and the limited knowledge of the structure of the hepatitis C virus (HCV) envelope glycoproteins (GP) are challenging hurdles for vaccine design. Recently, Kong et al. published a new model of HCV E2 GP structure in Science, revealing a globular structure, starkly contrasting from the extended model of class II fusion proteins from other Flaviviridae viruses. PMID:24626133

  10. AIR STRUCTURES FOR SCHOOL SPORTS.

    ERIC Educational Resources Information Center

    ROBERTSON, NAN

    AIR STRUCTURES ARE FABRIC BUILDINGS BLOWN UP AND HELD UP BY AIR PRESSURE. EXPERIMENTS WITH SUCH STRUCTURES WERE CONDUCTED AS EARLY AS 1917. IN 1948 THE UNITED STATES AIR FORCE SOUGHT A NEW WAY OF HOUSING LARGE RADAR ANTENNAE PLANNED FOR THE ARCTIC. AS AN OUTCOME OF THEIR SEARCH, BIRDAIR STRUCTURES, INC., WHICH IS NOW ONE OF SEVERAL COMPANIES…

  11. Air Structures for School Sports.

    ERIC Educational Resources Information Center

    Robertson, Nan

    Air structures are fabric buildings blown up and held up by air pressure. Experiments with such structures were conducted as early as 1917. In 1948 the United States Air Force sought a new way of housing large radar antennae planned for the arctic. As an outcome of their search, Birdair Structures, Inc., which is now one of several companies…

  12. Generalized Multilevel Structural Equation Modeling

    ERIC Educational Resources Information Center

    Rabe-Hesketh, Sophia; Skrondal, Anders; Pickles, Andrew

    2004-01-01

    A unifying framework for generalized multilevel structural equation modeling is introduced. The models in the framework, called generalized linear latent and mixed models (GLLAMM), combine features of generalized linear mixed models (GLMM) and structural equation models (SEM) and consist of a response model and a structural model for the latent…

  13. Ethnic family structure.

    PubMed

    Mcdonald, P

    1989-04-01

    Using information from large-scale statistical collections and elaborations from ethnographic studies, this paper examines the underlying social processes and structures of migrant families in Australia. Migrants in Australia are often confronted by family values and behavior which run counter to their own. For some migrants, particularly those from the United Kingdom and Western European countries, there is little conflict as Australian family values and behavior approximate their own; the feminine conception of the family is not foreign to them. On the other hand, migrants from Mediterranean countries and from Asia are likely to face a clash between the masculine conception of the family and the dominant feminine conception they find in Australia. Economic structure also often forces an accommodation to the feminine conception of the family. For example, migrant women in Australia are heavily involved in the work force outside the family circle, and, in the main, have relatively low fertility. Age at marriage is increasing and many single women of migrant origin are being educated at the tertiary level and are working before marriage. These changes necessarily expose women and youths to the dominant social values and increase their economic independence, thus disrupting the conventional male family authority. There is evidence of a degree of accommodation to Australian patterns of behavior in migrant groups more inclined to a masculine conception of the family. In other areas, however, which are less directly related to economic pressure, migrant values have been far less accommodating. There is still a high level of endogamy, the 1st birth occurs soon after marriage, divorce rates are low, and the aged are very likely to live with their children. Large migrant groups have been able to maintain these patterns of behavior through the formation of ethnic substructures that form their principal social environment. In the longer term, however, their children are

  14. Structural violence and schizophrenia.

    PubMed

    Kelly, Brendan D

    2005-08-01

    Despite clear evidence of a substantial biological basis to schizophrenia, there is also evidence that social, economic and political factors have considerable relevance to the clinical features, treatment and outcome of the illness. Individuals from lower socio-economic groups have an earlier age at first presentation and longer durations of untreated illness, both of which are associated with poor outcome. Individuals with schizophrenia are over-represented in the homeless population. Migration is associated with increased rates of mental illness, including schizophrenia, and this relationship appears to be mediated by psycho-social factors, including difficulties establishing social capital in smaller migrant groups. Individuals with schizophrenia are substantially over-represented amongst prison populations, and imprisonment increases the disability and stigma associated with mental illness, and impedes long-term recovery. The adverse effects of these social, economic and societal factors, along with the social stigma of mental illness, constitute a form of 'structural violence' which impairs access to psychiatric and social services and amplifies the effects of schizophrenia in the lives of sufferers. As a result of these over-arching social and economic factors, many individuals with schizophrenia are systematically excluded from full participation in civic and social life, and are constrained to live lives that are shaped by stigma, isolation, homelessness and denial of rights. There are urgent needs for (1) the development of enhanced aetiological models of schizophrenia, which elucidate the interactions between genetic risk and social environment, and can better inform bio-psycho-social approaches to treatment; (2) a renewal of emphasis on the United Nations' "Principles for the Protection of Persons with Mental Illness" and related legislative measures in individual countries; and (3) continued study and examination of the impact of social, economic and

  15. Hydrodynamic loading of tensegrity structures

    NASA Astrophysics Data System (ADS)

    Wroldsen, Anders S.; Johansen, Vegar; Skelton, Robert E.; Sørensen, Asgeir J.

    2006-03-01

    This paper introduces hydrodynamic loads for tensegrity structures, to examine their behavior in marine environments. Wave compliant structures are of general interest when considering large marine structures, and we are motivated by the aquaculture industry where new concepts are investigated in order to make offshore installations for seafood production. This paper adds to the existing models and software simulations of tensegrity structures exposed to environmental loading from waves and current. A number of simulations are run to show behavior of the structure as a function of pretension level and string stiffness for a given loading condition.

  16. Foam rigidized inflatable structural assemblies

    NASA Technical Reports Server (NTRS)

    Tinker, Michael L. (Inventor); Schnell, Andrew R. (Inventor)

    2010-01-01

    An inflatable and rigidizable structure for use as a habitat or a load bearing structure is disclosed. The structure consists of an outer wall and an inner wall defining a containment member and a bladder. The bladder is pressurized to erect the structure from an initially collapsed state. The containment member is subsequently injected with rigidizable fluid through an arrangement of injection ports. Exhaust gases from the curing rigidizable fluid are vented through an arrangement of exhaust ports. The rate of erection can be controlled by frictional engagement with a container or by using a tether. A method for fabricating a tubular structure is disclosed.

  17. Aircraft empennage structural detail design

    NASA Technical Reports Server (NTRS)

    Lesnewski, David; Snow, Russ M.; Combs, Lisa M.; Paufler, David; Schnieder, George; Athousake, Roxanne

    1993-01-01

    The purpose of this project is to provide an empennage structural assembly that will withstand the operational loads defined in FAR Part 23, as well as those specified in the statement of work, i.e. snow, rain, humidity, tiedown forces, etc. The goal is to provide a simple yet durable lightweight structure that will transfer the aerodynamic forces produced by the tail surfaces through the most efficient load path to the airframe. The structure should be simple and cost-effective to manufacture and repair. All structures meet or exceed loading and fatigue criteria. The structure provides for necessary stiffness and ease of maintenance.

  18. Analysing photonic structures in plants

    PubMed Central

    Vignolini, Silvia; Moyroud, Edwige; Glover, Beverley J.; Steiner, Ullrich

    2013-01-01

    The outer layers of a range of plant tissues, including flower petals, leaves and fruits, exhibit an intriguing variation of microscopic structures. Some of these structures include ordered periodic multilayers and diffraction gratings that give rise to interesting optical appearances. The colour arising from such structures is generally brighter than pigment-based colour. Here, we describe the main types of photonic structures found in plants and discuss the experimental approaches that can be used to analyse them. These experimental approaches allow identification of the physical mechanisms producing structural colours with a high degree of confidence. PMID:23883949

  19. Computational Methods For Composite Structures

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    1988-01-01

    Selected methods of computation for simulation of mechanical behavior of fiber/matrix composite materials described in report. For each method, report describes significance of behavior to be simulated, procedure for simulation, and representative results. Following applications discussed: effects of progressive degradation of interply layers on responses of composite structures, dynamic responses of notched and unnotched specimens, interlaminar fracture toughness, progressive fracture, thermal distortions of sandwich composite structure, and metal-matrix composite structures for use at high temperatures. Methods demonstrate effectiveness of computational simulation as applied to complex composite structures in general and aerospace-propulsion structural components in particular.

  20. A Molecular–Structure Hypothesis

    PubMed Central

    Boeyens, Jan C. A.

    2010-01-01

    The self-similar symmetry that occurs between atomic nuclei, biological growth structures, the solar system, globular clusters and spiral galaxies suggests that a similar pattern should characterize atomic and molecular structures. This possibility is explored in terms of the current molecular structure-hypothesis and its extension into four-dimensional space-time. It is concluded that a quantum molecule only has structure in four dimensions and that classical (Newtonian) structure, which occurs in three dimensions, cannot be simulated by quantum-chemical computation. PMID:21151437