WorldWideScience

Sample records for bonding and joining

  1. Joining of Silicon Carbide: Diffusion Bond Optimization and Characterization

    Science.gov (United States)

    Halbig, Michael C.; Singh, Mrityunjay

    2008-01-01

    Joining and integration methods are critically needed as enabling technologies for the full utilization of advanced ceramic components in aerospace and aeronautics applications. One such application is a lean direct injector for a turbine engine to achieve low NOx emissions. In the application, several SiC substrates with different hole patterns to form fuel and combustion air channels are bonded to form the injector. Diffusion bonding is a joining approach that offers uniform bonds with high temperature capability, chemical stability, and high strength. Diffusion bonding was investigated with the aid of titanium foils and coatings as the interlayer between SiC substrates to aid bonding. The influence of such variables as interlayer type, interlayer thickness, substrate finish, and processing time were investigated. Optical microscopy, scanning electron microscopy, and electron microprobe analysis were used to characterize the bonds and to identify the reaction formed phases.

  2. Joining of Silicon Carbide Through the Diffusion Bonding Approach

    Science.gov (United States)

    Halbig, Michael .; Singh, Mrityunjay

    2009-01-01

    In order for ceramics to be fully utilized as components for high-temperature and structural applications, joining and integration methods are needed. Such methods will allow for the fabrication the complex shapes and also allow for insertion of the ceramic component into a system that may have different adjacent materials. Monolithic silicon carbide (SiC) is a ceramic material of focus due to its high temperature strength and stability. Titanium foils were used as an interlayer to form diffusion bonds between chemical vapor deposited (CVD) SiC ceramics with the aid of hot pressing. The influence of such variables as interlayer thickness and processing time were investigated to see which conditions contributed to bonds that were well adhered and crack free. Optical microscopy, scanning electron microscopy, and electron microprobe analysis were used to characterize the bonds and to identify the reaction formed phases.

  3. Effects of Interlayer Composition on Bond Strength and Interfacial Microstructure of Green Joined CePO4-ZrO2 Ceramics

    Institute of Scientific and Technical Information of China (English)

    高海; 刘家臣; 刘名郑; 王丽娟; 霍伟荣

    2003-01-01

    Effects of interlayer composition on bonding strength and interfacial microstruc ture of green joined CePO4-ZrO2 ceramics were studied. Green bodies of 25%C ePO4/ZrO2 and ZrO2 ceramics were joined by using interlayer composed of Ce PO4 and ZrO2 at 1450 ℃ for 120 min without applied pressure.The effects of CePO4/(CePO4+ZrO2) ratio on the bond strength of the joints were investiga ted. Under the experimental conditions, the grain size of the particles grown in the joint is smaller than those in joined ceramics. The microstructure of the joint is more homogeneous than that of the matrix and without obvious cracks, pores and other defects.

  4. Microstructural and mechanical characterizations of steel tubes joined by transient liquid phase bonding using an amorphous Fe–B–Si interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Di Luozzo, Nicolas, E-mail: nicolasdiluozzo@gmail.com [Laboratorio de Sólidos Amorfos, INTECIN, Facultad de Ingeniería, Universidad de Buenos Aires – CONICET, Paseo Colón 850, C1063ACV Buenos Aires (Argentina); Laboratoire des Matériaux et du Génie Physique (CNRS UMR 5628), Grenoble Institute of Technology, MINATEC, Grenoble Cedex 1 (France); Doisneau, Béatrice; Boudard, Michel [Laboratoire des Matériaux et du Génie Physique (CNRS UMR 5628), Grenoble Institute of Technology, MINATEC, Grenoble Cedex 1 (France); Fontana, Marcelo; Arcondo, Bibiana [Laboratorio de Sólidos Amorfos, INTECIN, Facultad de Ingeniería, Universidad de Buenos Aires – CONICET, Paseo Colón 850, C1063ACV Buenos Aires (Argentina)

    2014-12-05

    Highlights: • We joined steel tubes by means of TLPB process using a Fe–B–Si foil as interlayer. • We characterized both microstructure and mechanical properties of the joint. • The microstructure at the joint consists only of ferrite grains. • Evidences of non-epitaxial solidification were found. • Both tensile and hardness tests show the soundness of the joint. - Abstract: In this work the transient liquid phase bonding process was successfully used to join seamless carbon steel tubes using an amorphous Fe–B–Si foil as interlayer. The tubes were aligned with their butted surfaces in contact with the interlayer and the entire assembly was heated by means of an induction furnace under a reducing atmosphere. The temperature was raised to the process temperature (≈1300 °C) and then held for 7 min. The joining process was performed under a pressure of 5 MPa. The joined tubes microstructures were characterized by direct observations – scanning electron microscopy – and diffraction techniques – electron backscatter diffraction. Chemical analysis was performed by electron probe microanalysis. The joint region (JR) presents only ferrite grains - in contrast with the heat affected zone (HAZ) and the base metal (BM), whose microstructures consist of ferrite and cementite. Si content at the JR was precisely determined by chemical profiling, showing higher concentrations of Si compared with the HAZ and BM. These results are in accordance with the fact that the cementite is unable to form in Si enriched zones. Also, ferrite grains at the JR present high-angle grain boundaries with respect to the grains of the HAZ. Tensile tests show that the joined tubes failed away from the bond, at the HAZ, and reached 96% of the ultimate tensile strength of the BM, in the as-bonded condition. Microindentation hardness profiles across the bonding zone are in agreement with the observed microstructures at the different zones of the bond region.

  5. Joining mechanism of field-assisted diffusion bonding of solid electrolyte ceramic to metals

    Institute of Scientific and Technical Information of China (English)

    孟庆森; 薛锦

    2003-01-01

    Field-assisted diffusion bonding applied in the joining of solid electrolyte borosilicate glass, β″-Al2O3, Y2O-ZrO2 to monocrystal silicate and aluminum were proceeded with bonding machine in the assistance of static electric field. TEM, SEM, XRD and other means were applied to investigate and analyze microstructure of interface. It is supposed that the interfacial area is a model of metal-oxides-ceramic, and the joining mechanism is solid diffusion joining and static electric bonding. The process of ions migration and accumulation under electric field is the most essential factor for the anodic oxidation and interfacial joining. Temperature and voltage are the basic factors of the solid diffusion bonding of interfacial oxidation. And voltage, temperature, pressure and the condition of surface are the most important factors that govern the bonding process.

  6. Effect of Bonding Temperature on the Joining of Ti-6Al-4V Alloy Using Cu Coatings and Sn Interlayers

    Science.gov (United States)

    AlHazaa, Abdulaziz N.; AlGharbi, Sultan H.; Nishikawa, Hiroshi

    2016-11-01

    Titanium alloy Ti-6Al-4V samples were bonded together using Cu coatings and Sn interlayers. The bonding of titanium samples was successful at various temperatures (700-950 °C) which are below the β-transus temperature of Ti-6Al-4V alloy. An applied uniaxial pressure of 1 MPa and a short bonding time of 15 min were selected as bonding parameters. Scanning electron microscope and energy-dispersive spectroscopy showed that the dissolution of Ti in the joint region increases with the increase in bonding temperature. X-ray diffraction analysis of the fractured surfaces revealed that Sn5Ti6, Sn3Ti5 and SnTi3 intermetallic compounds (IMCs) were formed and dominated the joint structure. The shear strengths of the bonds increase with the increase in bonding temperature and reaches a maximum of 478 MPa for bond made at 950 °C. The microhardness analysis of the fractured surfaces compared to the base alloy confirmed the presence of the IMCs. X-ray photoelectron spectroscopy (XPS) analysis showed the presence of Ti at the top surface of the fractured bonds made at 700 °C which confirmed a successful joint evolution even at the lowest bonding temperature used. Atomic force microscopy observations for bonds made at 700 and 950 °C coincide with the XRD and XPS analysis and were able to reveal the remaining Cu particles on the substrates.

  7. Joining of SiC Fiber-Bonded Ceramics using Silver, Copper, Nickel, Palladium, and Silicon-Based Alloy Interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Asthana, Rajiv [University of Wisconsin-Stout, Menomonie; Singh, Mrityunjay [NASA-Glenn Research Center, Cleveland; Lin, Hua-Tay [ORNL; Matsunaga, Kenji [Ube Industries, Ltd.; Ishikawa, Toshihiro [Ube Industries, Ltd.

    2013-01-01

    SiC fiber-bonded ceramics, SA-Tyrannohex, (SA-THX) with perpendicular and parallel fiber orientations were brazed using Ag-, Ni- and Pd-base brazes, and four Si X (X: Ti, Cr, Y, Ta) eutectics. Outcomes were variable, ranging from bonded joints through partially bonded to un-bonded joints. Prominent Ti- and Si-rich interfaces developed with Cusil-ABA, Ticusil, and Copper-ABA and Ni- and Si-rich layers with MBF-20. Stress rupture tests at 650 and 750 C on Cusil-ABA-bonded joints revealed a temperature-dependent behavior for the perpendicular joints but not for the parallel joints with failure occurring at brazed interface. Higher-use temperatures can be targeted with eutectic Si Ti and Si Cr alloys.

  8. Welding and Joining of Titanium Aluminides

    Directory of Open Access Journals (Sweden)

    Jian Cao

    2014-06-01

    Full Text Available Welding and joining of titanium aluminides is the key to making them more attractive in industrial fields. The purpose of this review is to provide a comprehensive overview of recent progress in welding and joining of titanium aluminides, as well as to introduce current research and application. The possible methods available for titanium aluminides involve brazing, diffusion bonding, fusion welding, friction welding and reactive joining. Of the numerous methods, solid-state diffusion bonding and vacuum brazing have been most heavily investigated for producing reliable joints. The current state of understanding and development of every welding and joining method for titanium aluminides is addressed respectively. The focus is on the fundamental understanding of microstructure characteristics and processing–microstructure–property relationships in the welding and joining of titanium aluminides to themselves and to other materials.

  9. Laser-assisted direct joining of AISI304 stainless steel with polycarbonate sheets: Thermal analysis, mechanical characterization, and bonds morphology

    Science.gov (United States)

    Lambiase, F.; Genna, S.

    2017-02-01

    Laser-Assisted Metal and Plastic bonding (LAMP) of AISI304 sheets with polycarbonate sheets is investigated in this work. The process was performed by means of a high power diode laser with a maximum power of 200 W. The study introduces an integrated experimental approach aimed at understanding how the main process conditions (laser power and scanning speed) influence the direct-bonds quality, dimensions and presence of defects. To this end, the bonds dimension, shear strength, formation and dimension of bubbles in the bonded region were related to the temperature measurements and process parameters. According to the achieved results, the processing window that enables a good adhesion of the two materials is relatively small; this is due the activation of the adhesion phenomena that require overcoming an energy threshold. However, excessive energy levels reduce the bonds strength due to the increase in defects (bubbles) dimension that may combine (coalescence) leading to the formation of a central tunnel where the two substrates are completely detached.

  10. Fast and scalable inequality joins

    KAUST Repository

    Khayyat, Zuhair

    2016-09-07

    Inequality joins, which is to join relations with inequality conditions, are used in various applications. Optimizing joins has been the subject of intensive research ranging from efficient join algorithms such as sort-merge join, to the use of efficient indices such as (Formula presented.)-tree, (Formula presented.)-tree and Bitmap. However, inequality joins have received little attention and queries containing such joins are notably very slow. In this paper, we introduce fast inequality join algorithms based on sorted arrays and space-efficient bit-arrays. We further introduce a simple method to estimate the selectivity of inequality joins which is then used to optimize multiple predicate queries and multi-way joins. Moreover, we study an incremental inequality join algorithm to handle scenarios where data keeps changing. We have implemented a centralized version of these algorithms on top of PostgreSQL, a distributed version on top of Spark SQL, and an existing data cleaning system, Nadeef. By comparing our algorithms against well-known optimization techniques for inequality joins, we show our solution is more scalable and several orders of magnitude faster. © 2016 Springer-Verlag Berlin Heidelberg

  11. Structural Join and Staircase Join Algorithms of Sibling Relationship

    Institute of Scientific and Technical Information of China (English)

    Chang-Xuan Wan; Xi-Ping Liu

    2007-01-01

    The processing of XML queries can result in evaluation of various structural relationships. Efficient algorithms for evaluating ancestor-descendant and parent-child relationships have been proposed. Whereas the problems of evaluating preceding-sibling-following-sibling and preceding-following relationships are still open. In this paper, we studied the struc-tural join and staircase join for sibling relationship. First, the idea of how to filter out and minimize unnecessary reads of elements using parent's structural information is introduced, which can be used to accelerate structural joins of parent-child and preceding-sibling-following-sibling relationships. Second, two efficient structural join algorithms of sibling relationship are proposed. These algorithms lead to optimal join performance: nodes that do not participate in the join can be judged beforehand and then skipped using B+-tree index. Besides, each element list joined is scanned sequentially once at most.Furthermore, output of join results is sorted in document order. We also discussed the staircase join algorithm for sibling axes. Studies show that, staircase join for sibling axes is close to the structural join for sibling axes and shares the samecharacteristic of high efficiency. Our experimental results not only demonstrate the effectiveness of our optimizing techniquesfor sibling axes, but also validate the efficiency of our algorithms. As far as we know, this is the first work addressing thisproblem specially.

  12. Basic investigation about a new joining process called HFDB (Hybrid Friction Diffusion Bonding); Grundlegende Untersuchung ueber ein neues Schweissverfahren namens HFDB (Hybrid Friction Diffusion Bonding)

    Energy Technology Data Exchange (ETDEWEB)

    Roos, Arne

    2010-07-01

    Scientific and technological objectives in the area of joining of materials for the transportation and energy industry have been the motivation for the development of a new joining method. For integral structures in aircraft a joining technology that is capable of joining metals which differ significantly in melting temperature and strength like titanium and aluminium is needed. In composite structures thin aluminium foils should be welded without degrading or destroying the intermediate polymers. Joining at low temperatures without mixing the joining partners is therefore desirable. Most of today's joining methods do not fulfil these requirements. In the course of this thesis a new joining technology named HFDB (Hybrid Friction Diffusion Bonding) has been developed. With this new joining technology the joining of similar and dissimilar materials of varying thicknesses (AA 2024; Al 7075; Al 99,5; 1.4301; Ti6Al4V; AZ31 in 0,1 mm up to 0,7 mm) as well as the manufacturing of a prototype for a heat-exchanger has been investigated. In addition a clamping set-up for the thin sheets has been developed and tested to avoid buckling during joining. Characterisation of the new bonding method has been established by means of metallographic procedures as well as mechanical testing (REM, {mu}CT, Nanoindenter, EDX, peel- and shear tensile tests, optical microscopy). Results of EDX as well as nano-indentation show a metallic joint in Aluminium /Aluminium as well as Aluminium / Titanium joints. A comparison of HFDB and DB results of the mechanical characterisation show comparable peel results at a significant lower heat input and processing time for HFDB. {mu}CT results show no vertical mixing of the materials across the bonding line. Only horizontal movement of the marker material can be observed. A micro structural investigation in combination with an analytical comparison shows a diffusion dominated joining mechanism. Furthermore the energy input and the bonding mechanism

  13. Machining, joining and modifications of advanced materials

    CERN Document Server

    Altenbach, Holm

    2016-01-01

    This book presents the latest advances in mechanical and materials engineering applied to the machining, joining and modification of modern engineering materials. The contributions cover the classical fields of casting, forming and injection moulding as representative manufacturing methods, whereas additive manufacturing methods (rapid prototyping and laser sintering) are treated as more innovative and recent technologies that are paving the way for the manufacturing of shapes and features that traditional methods are unable to deliver. The book also explores water jet cutting as an innovative cutting technology that avoids the heat build-up typical of classical mechanical cutting. It introduces readers to laser cutting as an alternative technology for the separation of materials, and to classical bonding and friction stir welding approaches in the context of joining technologies. In many cases, forming and machining technologies require additional post-treatment to achieve the required level of surface quali...

  14. Lightning fast and space efficient inequality joins

    KAUST Repository

    Khayyat, Zuhair

    2015-09-01

    Inequality joins, which join relational tables on inequality conditions, are used in various applications. While there have been a wide range of optimization methods for joins in database systems, from algorithms such as sort-merge join and band join, to various indices such as B+-tree, R*-tree and Bitmap, inequality joins have received little attention and queries containing such joins are usually very slow. In this paper, we introduce fast inequality join algorithms. We put columns to be joined in sorted arrays and we use permutation arrays to encode positions of tuples in one sorted array w.r.t. the other sorted array. In contrast to sort-merge join, we use space efficient bit-arrays that enable optimizations, such as Bloom filter indices, for fast computation of the join results. We have implemented a centralized version of these algorithms on top of PostgreSQL, and a distributed version on top of Spark SQL. We have compared against well known optimization techniques for inequality joins and show that our solution is more scalable and several orders of magnitude faster.

  15. Lightning Fast and Space Efficient Inequality Joins

    KAUST Repository

    Khayyat, Zuhair

    2015-09-01

    Inequality joins, which join relational tables on inequality conditions, are used in various applications. While there have been a wide range of optimization methods for joins in database systems, from algorithms such as sort-merge join and band join, to various indices such as B+-tree,R*-tree and Bitmap, inequality joins have received little attention and queries containing such joins are usually very slow. In this paper, we introduce fast inequality join algorithms. We put columns to be joined in sorted arrays and we use permutation arrays to encode positions of tuples in one sorted array w.r.t. the other sorted array. In contrast to sort-merge join, we use space effcient bit-arrays that enable optimizations, such as Bloom filter indices, for fast computation of the join results. We have implemented a centralized version of these algorithms on top of PostgreSQL, and a distributed version on top of Spark SQL. We have compared against well known optimization techniques for inequality joins and show that our solution is more scalable and several orders of magnitude faster.

  16. Effect of joining temperature on microstructure and properties of diffusion bonded Mg/Al joints%焊接温度对Mg/Al扩散焊接头微观组织和性能的影响

    Institute of Scientific and Technical Information of China (English)

    尚晶; 王克鸿; 周琦; 张德库; 黄俊; 葛佳棋

    2012-01-01

    The joining of AZ31B Mg alloy to 6061 Al alloy was investigated at different joining temperatures by vacuum diffusion bonding method.The microstructures of Mg/Al dissimilar joints were studied by means of optical microscopy (OM),scanning electron microscopy (SEM) and energy dispersive X-ray (EDX).The results show that the thickness of each layer in the diffusion zone increases with the increase of joining temperature,and the microstructure changes obviously.At joining temperature of 440 ℃,the diffusion zone is composed of Mg2Al3 layer and Mg17Al12 layer.At joining temperatures of 460 and 480 ℃,the diffusion zone is composed of Mg2Al3 layer,Mg17Al12 layer,eutectic layer of Mg17Al12 and Mg-based solid solution.The width of high-hardness zone in the joint increases with increasing joining temperature,and the micro-hardnesses at different locations in the diffusion zone are csignificantly different.The joining temperature of 440 ℃ offers the highest tensile strength of 37 MPa,and the corresponding joint exhibits brittle fracture at the intermetallic compound layer of Mg17Al12.%采用真空扩散焊在不同焊接温度下对AZ31B镁合金和6061铝合金进行连接.利用光学显微镜(OM)、扫描电镜(SEM)和能谱(EDX)观察Mg/Al异种金属接头的显微组织.结果表明:随着焊接温度的升高,扩散区各层的厚度增加,且组织发生明显变化.440℃时扩散层由Mg2Al3层和Mg17Al12层组成;460和480℃时由Mg2Al3层、Mg17Al12层和Mg17Al12与镁基固溶体的共晶层组成.随着加热温度的升高,高硬度区域显著增多,区域内不同位置的硬度存在明显差别.当焊接温度为440℃时接头的最大抗拉强度为37 MPa,脆性断裂发生在Mg17Al12层.

  17. Ceramic joining

    Energy Technology Data Exchange (ETDEWEB)

    Loehman, R.E. [Sandia National Lab., Albuquerque, NM (United States)

    1996-04-01

    This paper describes the relation between reactions at ceramic-metal interfaces and the development of strong interfacial bonds in ceramic joining. Studies on a number of systems are described, including silicon nitrides, aluminium nitrides, mullite, and aluminium oxides. Joints can be weakened by stresses such as thermal expansion mismatch. Ceramic joining is used in a variety of applications such as solid oxide fuel cells.

  18. Microwave joining of SiC ceramics and composites

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Silberglitt, R.; Tian, Y.L. [FM Technologies, Inc., Fairfax, VA (United States); Katz, J.D. [Los Alamos National Lab., NM (United States)

    1997-04-01

    Potential applications of SiC include components for advanced turbine engines, tube assemblies for radiant burners and petrochemical processing and heat exchangers for high efficiency electric power generation systems. Reliable methods for joining SiC are required in order to cost-effectively fabricate components for these applications from commercially available shapes and sizes. This manuscript reports the results of microwave joining experiments performed using two different types of SiC materials. The first were on reaction bonded SiC, and produced joints with fracture toughness equal to or greater than that of the base material over an extended range of joining temperatures. The second were on continuous fiber-reinforced SiC/SiC composite materials, which were successfully joined with a commercial active brazing alloy, as well as by using a polymer precursor.

  19. High Temperature Joining and Characterization of Joint Properties in Silicon Carbide-Based Composite Materials

    Science.gov (United States)

    Halbig, Michael C.; Singh, Mrityunjay

    2015-01-01

    Advanced silicon carbide-based ceramics and composites are being developed for a wide variety of high temperature extreme environment applications. Robust high temperature joining and integration technologies are enabling for the fabrication and manufacturing of large and complex shaped components. The development of a new joining approach called SET (Single-step Elevated Temperature) joining will be described along with the overview of previously developed joining approaches including high temperature brazing, ARCJoinT (Affordable, Robust Ceramic Joining Technology), diffusion bonding, and REABOND (Refractory Eutectic Assisted Bonding). Unlike other approaches, SET joining does not have any lower temperature phases and will therefore have a use temperature above 1315C. Optimization of the composition for full conversion to silicon carbide will be discussed. The goal is to find a composition with no remaining carbon or free silicon. Green tape interlayers were developed for joining. Microstructural analysis and preliminary mechanical tests of the joints will be presented.

  20. Joining of advanced materials

    CERN Document Server

    Messler, Robert W

    1993-01-01

    Provides an unusually complete and readable compilation of the primary and secondary options for joining conventional materials in non-conventional ways. Provides unique coverage of adhesive bonding using both organic and inorganic adhesives, cements and mortars. Focuses on materials issues without ignoring issues related to joint design, production processing, quality assurance, process economics, and joining performance in service.Joining of advanced materials is a unique treatment of joining of both conventional and advanced metals andalloys, intermetallics, ceramics, glasses, polymers, a

  1. JOINING MECHANISM OF FIELD-ASSISTED BONDING OF ELECTROLYTE GLASS TO METALS

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Investigations of technological characteristics and bonding mechanism of field-assisted bonding are done, which are for bonding of electrolytes (Pyrex glass) to monocrystal silicon and aluminum. The features of microstructure and the distribution of the diffused elements in the bonding interface area are studied by means of SEM, EDX and XRD, and the influence of the technological factors on the bonding process is also studied. The model of"metal-oxides-glass"of bonding structure and ions diffusion and bonding in the condition of electrical field-assisted are indicated.

  2. Joining and Integration of Silicon Carbide for Turbine Engine Applications

    Science.gov (United States)

    Halbig, Michael C.; Singh, Mrityunjay; Coddington, Bryan; Asthana, Rajiv

    2010-01-01

    The critical need for ceramic joining and integration technologies is becoming better appreciated as the maturity level increases for turbine engine components fabricated from ceramic and ceramic matrix composite materials. Ceramic components offer higher operating temperatures and reduced cooling requirements. This translates into higher efficiencies and lower emissions. For fabricating complex shapes, diffusion bonding of silicon carbide (SiC) to SiC is being developed. For the integration of ceramic parts to the surrounding metallic engine system, brazing of SiC to metals is being developed. Overcoming the chemical, thermal, and mechanical incompatibilities between dissimilar materials is very challenging. This presentation will discuss the types of ceramic components being developed by researchers and industry and the benefits of using ceramic components. Also, the development of strong, crack-free, stable bonds will be discussed. The challenges and progress in developing joining and integration approaches for a specific application, i.e. a SiC injector, will be presented.

  3. Human-powered Sorts and Joins

    CERN Document Server

    Marcus, Adam; Karger, David; Madden, Samuel; Miller, Robert

    2011-01-01

    Crowdsourcing markets like Amazon's Mechanical Turk (MTurk) make it possible to task people with small jobs, such as labeling images or looking up phone numbers, via a programmatic interface. MTurk tasks for processing datasets with humans are currently designed with significant reimplementation of common workflows and ad-hoc selection of parameters such as price to pay per task. We describe how we have integrated crowds into a declarative workflow engine called Qurk to reduce the burden on workflow designers. In this paper, we focus on how to use humans to compare items for sorting and joining data, two of the most common operations in DBMSs. We describe our basic query interface and the user interface of the tasks we post to MTurk. We also propose a number of optimizations, including task batching, replacing pairwise comparisons with numerical ratings, and pre-filtering tables before joining them, which dramatically reduce the overall cost of running sorts and joins on the crowd. In an experiment joining tw...

  4. Recent progress in ceramic joining

    Energy Technology Data Exchange (ETDEWEB)

    Loehman, R.E.

    1998-09-01

    Both fundamental and practical aspects of ceramic joining are understood well enough for many, if not most, applications requiring moderate strengths at room temperature. This paper argues that the two greatest needs in ceramic joining are for techniques to join buried interfaces by selective heating, and methods for joining ceramics for use at temperatures of 800 to 1,200 C. Heating with microwave radiation or with high-energy electron beams has been used to join buried ceramic interfaces, for example SiC to SiC. Joints with varying levels of strength at temperatures of 600 to 1,000 C have been made using four techniques: (1) transient liquid phase bonding; (2) joining with refractory braze alloys; (3) joining with refractory glass compositions; and (4) joining using preceramic polymers. Joint strengths as high as 550 MPa at 1,000 C have been reported for silicon nitride-silicon nitride bonds tested in four-point flexure.

  5. Progress in Joining Ceramics to Metals

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The research and development of joining methods of ceramics to metals, especially brazing, diffusion bonding and partial transition liquid phase bonding, were introduced. Some opinions were put forward. For new composites emerging, it is necessary to develop new joining methods, particularly in the field of high temperature technique for joining ceramics to superalloys.

  6. Possibilities of joining techniques application at railway lines joining and maintenance

    Directory of Open Access Journals (Sweden)

    I. Samardžić

    2011-10-01

    Full Text Available This paper presents most important techniques which is possible to apply at joining of railway lines as well as maintenance procedure. Beside thermit welding as a older joint process for that job (since 1895. it is mentioned flash welding as a modern joining technique interesting from the point of cost efficiency. In a case of maintance tasks it is necessary to caunt arc welding processes and thermit welding, too. Authors gave some experimental date collected during investigation on railway lines joining techniques application.

  7. Joining and surfacing of advanced materials

    Institute of Scientific and Technical Information of China (English)

    Andrzej Kolasa; Wladyslaw Wlosinski

    2004-01-01

    The application of advanced materials, i.e. advanced ceramics, glasses, intermetallic phases and various type of composites, not only depends on their manufacture processes including a great input of know-how, but also on their abilities for processing, among which the joining processes play an important role. The uses of advanced materials are changing rapidly, with a major emphasis on technical applications, especially the components of machines, apparatus and technical devices expected to withstand very heavy exploitation conditions. Furthermore,these materials are becoming more complex, in terms of being strengthened and toughened by transformation processes as well as by the addition of other ceramic or metallic materials including nanomaterials. The successful use of advanced materials requires the development of equally advanced joining materials, processes and technology. Some selected examples of results of joining advanced materials with the use of various procedures as well as surface modification of structural components with the use of advanced materials obtained in the Welding Engineering Department of Warsaw University of Technology, Poland, are presented.

  8. MICROWAVE JOINING OF ALUMINA CERAMIC AND HYDROXYLAPATITE BIOCERAMIC

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Microwave joining is a rapid developmental new techniqu e in recent years.This paper introduces a new microwave joining equipment which was made by our lab,succeeds in alumina ceramic-hydroxylapatite bioceramic j o in in the equipment, and analyzes the join situation of join boundary by using s canni ng electron microscope(SEM),this paper analyzes the mechanism of microwave joini ng also.

  9. Robust Joining and Integration Technologies for Advanced Metallic, Ceramic, and Composite Systems

    Science.gov (United States)

    Singh, M.; Shpargel, Tarah; Morscher, Gregory N.; Halbig, Michael H.; Asthana, Rajiv

    2006-01-01

    Robust integration and assembly technologies are critical for the successful implementation of advanced metallic, ceramic, carbon-carbon, and ceramic matrix composite components in a wide variety of aerospace, space exploration, and ground based systems. Typically, the operating temperature of these components varies from few hundred to few thousand Kelvin with different working times (few minutes to years). The wide ranging system performance requirements necessitate the use of different integration technologies which includes adhesive bonding, low temperature soldering, active metal brazing, diffusion bonding, ARCJoinT, and ultra high temperature joining technologies. In this presentation, a number of joining examples and test results will be provided related to the adhesive bonding and active metal brazing of titanium to C/C composites, diffusion bonding of silicon carbide to silicon carbide using titanium interlayer, titanium and hastelloy brazing to silicon carbide matrix composites, and ARCJoinT joining of SiC ceramics and SiC matrix composites. Various issues in the joining of metal-ceramic systems including thermal expansion mismatch and resulting residual stresses generated during joining will be discussed. In addition, joint design and testing issues for a wide variety of joints will be presented.

  10. Effects of Applied Load on 6061-T6 Aluminum Joined Employing a Novel Friction Bonding Process

    Science.gov (United States)

    Burkes, Douglas E.; Hallinan, Neil P.; Shropshire, Karen L.; Wells, Peter B.

    2008-12-01

    Friction bonding is under consideration for use in mass production of plate-type nuclear fuels for research reactors. This article discusses the effects of applied load (the most important process parameter for fabrication of these fuels) on temperature distribution, microstructure, and mechanical properties. Friction bonding experiments showed that tool geometry caused temperature gradients across the tool surface. Temperatures at the joint interface suggested the advancing side of the tool produced a majority of the frictional heat, while the retreating side of the tool mainly forged the plasticized material while bonding increased with applied load. The microstructure across the tool surface was also altered and, as a function of applied load, affected the mechanical properties. The 6061 aluminum alloy had mechanical properties close to a T4 temper after processing. Results documented in this article will aid in continual enhancement of friction bonding for nuclear fuel plate fabrication, and will hopefully contribute to continued advancement of friction stir welding (FSW) state of the art.

  11. Effect of Ti and Si interlayer materials on the joining of SiC ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yang Il; Park, Jung Hwan; Kim, Hyun Gil; Park, Dong Jun; Park, Jeong Yong; Kim, Weon Ju [LWR Fuel Technology Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-08-15

    SiC-based ceramic composites are currently being considered for use in fuel cladding tubes in light-water reactors. The joining of SiC ceramics in a hermetic seal is required for the development of ceramic-based fuel cladding tubes. In this study, SiC monoliths were diffusion bonded using a Ti foil interlayer and additional Si powder. In the joining process, a very low uniaxial pressure of ∼0.1 MPa was applied, so the process is applicable for joining thin-walled long tubes. The joining strength depended strongly on the type of SiC material. Reaction-bonded SiC (RB-SiC) showed a higher joining strength than sintered SiC because the diffusion reaction of Si was promoted in the former. The joining strength of sintered SiC was increased by the addition of Si at the Ti interlayer to play the role of the free Si in RB-SiC. The maximum joint strength obtained under torsional stress was ∼100 MPa. The joint interface consisted of TiSi{sub 2}, Ti{sub 3}SiC{sub 2}, and SiC phases formed by a diffusion reaction of Ti and Si.

  12. Conjoint Forming - Technologies for Simultaneous Forming and Joining

    Science.gov (United States)

    Groche, P.; Wohletz, S.; Mann, A.; Krech, M.; Monnerjahn, V.

    2016-03-01

    The market demand for new products optimized for e. g. lightweight applications or smart components leads to new challenges in production engineering. Hybrid structures represent one promising approach. They aim at higher product performance by using a suitable combination of different materials. The developments of hybrid structures stimulate the research on joining of dissimilar materials. Since they allow for joining dissimilar materials without external heating technologies based on joining by plastic deformation seem to be of special attractiveness. The paper at hand discusses the conjoint forming approach. This approach combines forming and joining in one process. Two or more workpieces are joined while at least one workpiece is plastically deformed. After presenting the fundamental joining mechanisms, the conjoint forming approach is discussed comprehensively. Examples of conjoint processes demonstrate the effectiveness and reveal the underlying phenomena.

  13. Study on join method of reaction bonded silicon carbide green body%RBSiC陶瓷素坯连接研究

    Institute of Scientific and Technical Information of China (English)

    张舸

    2014-01-01

    The join slurry is composed by silicon carbide (SiC) powder, phenolic resin and carbon black. Joining SiC green body after deairing, and then the reaction bonded SiC(RBSiC) joining mirror blank was prepared by reaction sintering. The relationship of the slurry formula and the microstructure of weld were discussed. The bending strength and the coefficient of thermal expansion of joining RBSiC ceramic were tested. The research shows that PEG200 and PVP can make carbon black dispersing homogeneous in the join slurry, and there is no residual carbon black in the weld after reaction sintering, so the microstructure of RBSiC ceramic is no different from the weld. The blending strength of joining green body and joining RBSiC ceramic are 24.9 MPa and 322.9 MP arespectively, and the fracture occurred in the base material. The ΔCTE of base and weld material is only 0.011 4 ppm during - 100- 400℃.%将碳化硅( Si C )微粉、酚醛树脂和炭黑等均匀混合,配置成连接浆料,真空除泡后连接SiC陶瓷素坯,高温反应烧结后得到反应烧结SiC(RBSiC)连接镜坯。讨论了浆料配方对焊缝显微结构的影响,测试了RBSiC连接坯体的力学性能和线膨胀系数。研究表明:连接浆料中加入聚乙二醇200(PEG200)和聚乙烯醇吡咯烷酮(PVP),能够有效分散炭黑,保证反应烧结过程中炭黑与硅完全反应,无残余碳存在,实现焊缝与基材之间显微结构的一致性;SiC连接坯体素坯和反应烧结后的抗弯强度值分别24.9 MPa和322.9 MPa,而且断裂位置在基材上;在-100~400℃范围内,RBSiC连接坯体与基体线膨胀系数差异仅为0.0114 ppm。

  14. Joining and fabrication techniques for high temperature structures including the first wall in fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jin; Lee, B. S.; Kim, K. B

    2003-09-01

    The materials for PFC's (Plasma Facing Components) in a fusion reactor are severely irradiated with fusion products in facing the high temperature plasma during the operation. The refractory materials can be maintained their excellent properties in severe operating condition by lowering surface temperature by bonding them to the high thermal conducting materials of heat sink. Hence, the joining and bonding techniques between dissimilar materials is considered to be important in case of the fusion reactor or nuclear reactor which is operated at high temperature. The first wall in the fusion reactor is heated to approximately 1000 .deg. C and irradiated severely by the plasma. In ITER, beryllium is expected as the primary armour candidate for the PFC's; other candidates including W, Mo, SiC, B4C, C/C and Si{sub 3}N{sub 4}. Since the heat affected zones in the PFC's processed by conventional welding are reported to have embrittlement and degradation in the sever operation condition, both brazing and diffusion bonding are being considered as prime candidates for the joining technique. In this report, both the materials including ceramics and the fabrication techniques including joining technique between dissimilar materials for PFC's are described. The described joining technique between the refractory materials and the dissimilar materials may be applicable for the fusion reactor and Generation-4 future nuclear reactor which are operated at high temperature and high irradiation.

  15. Fastening, coupling and joining technique between diaspora and irredenta

    Science.gov (United States)

    Bauer, C.-O.

    1980-06-01

    The problem of eliminating the present divergence and shattering (diaspora) in the treatment of problems of the fastening, coupling, and joining technique on different technical branches is examined. It is shown that by an appropriate independence the fastening, coupling and joining techniques can recognize and consequently utilize the numerous performance reserves which are concealed by the present organization and action due to the lack of systematically tended works.

  16. Joining of SiC ceramics and SiC/SiC composites

    Energy Technology Data Exchange (ETDEWEB)

    Rabin, B.H. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1995-08-01

    This project has successfully developed a practical and reliable method for fabricating SiC ceramic-ceramic joints. This joining method has the potential to facilitate the use of SiC-based ceramics in a variety of elevated temperature fossil energy applications. The technique is based on a reaction bonding approach that provides joint interlayers compatible with SiC, and excellent joint mechanical properties at temperatures exceeding 1000{degrees}C. Recent efforts have focused on transferring the joining technology to industry. Several industrial partners have been identified and collaborative research projects are in progress. Investigations are focusing on applying the joining method to sintered a-SiC and fiber-reinforced SiC/SiC composites for use in applications such as heat exchangers, radiant burners and gas turbine components.

  17. Combustion based technique for synthesis and joining of refractory materials

    Science.gov (United States)

    White, Jeremiah David Edward

    Gasless combustion systems offer features that make them attractive tools for a variety of potential applications. Among them are rapid heating rates, high exothermicity, and high maximum temperatures. These characteristics were exploited to accomplish three separate concepts including the joining of refractory materials, synthesis of a pore-free composite, and the study of thermal explosion in mechanically activated powders. Honeywell Aerospace is a leading producer of carbon brakes for commercial aircraft. The manufacturing process involves chemical vapor infiltration (CVI) to form a carbon matrix around a carbon fiber preform. A major disadvantage of this approach is the time required to form a fully dense preform, which is on the order of 140 days. In addition, after the brakes are in service, they have to be discarded while there is a relatively thick amount of friction material still available. There is a profit motive for reusing these discs which are out of spec. One such example would be to perform a refurbishment by bonding a new thin C/C element onto a used "core" to produce a brake that meets performance specifications. Unfortunately, joining C/C composites is not a simple task, as carbon does not lend itself to welding, and other means (e.g. mechanical or adhesives) would not hold up to the harsh operational conditions. A novel apparatus was designed, built, and proven to join C/C using so-called reactive resistance welding (RRW). It is shown that a joint stronger than the original material can be achieved using moderate electrical current and mechanical force. Additionally, joining layers of similar thickness and microstructure were obtained with different reactive media, ranging from pellets of pressed powders (˜1-2 mm) to thin metal foils (˜25 micron). By modifying the schematic of the RRW apparatus, porous C/C was infiltrated with liquid silicon in order to form a new pore-free C/C-SiC composite. It is shown that using such a process, the silicon

  18. Method of joining ceramics

    Science.gov (United States)

    Henager, Jr., Charles H.; Brimhall, John L.

    2000-01-01

    According to the method of the present invention, joining a first bi-element carbide to a second bi-element carbide, has the steps of: (a) forming a bond agent containing a metal carbide and silicon; (b) placing the bond agent between the first and second bi-element carbides to form a pre-assembly; and (c) pressing and heating the pre-assembly in a non-oxidizing atmosphere to a temperature effective to induce a displacement reaction creating a metal silicon phase bonding the first and second bi-element carbides.

  19. Joining Techniques for Ferritic ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    V.G. Krishnardula; V.G. Krishnardula; D.E. Clark; T.C. Totemeier

    2005-06-01

    This report presents results of research on advanced joining techniques for ferritic oxide-dispersion strengthened alloys MA956 and PM2000. The joining techniques studied were resistance pressure welding (also known as pressure forge welding), transient liquid phase bonding, and diffusion bonding. All techniques were shown to produce sound joints in fine-grained, unrecrystallized alloys. Post-bond heat treatment to produce a coarse-grained, recrystallized microstructure resulted in grain growth across the bondline for transient liquid phase and diffusion bonds, giving microstructures essentially identical to that of the parent alloy in the recrystallized condition. The effects of bond orientation, boron interlayer thickness, and bonding parameters are discussed for transient liquid phase and diffusion bonding. The report concludes with a brief discussion of ODS joining techniques and their applicability to GEN IV reactor systems.

  20. Determinant and inverse of join matrices on two sets

    CERN Document Server

    Mattila, Mika

    2011-01-01

    Let $(P,\\preceq)$ be a lattice and $f$ a complex-valued function on $P$. We define meet and join matrices on two arbitrary subsets $X$ and $Y$ of $P$ by $(X,Y)_f=(f(x_i\\wedge y_j))$ and $[X,Y]_f=(f(x_i\\vee x_j))$ respectively. Here we present expressions for the determinant and the inverse of $[X,Y]_f$. Our main goal is to cover the case when $f$ is not semimultiplicative since the formulas presented earlier for $[X,Y]_f$ cannot be applied in this situation. In cases when $f$ is semimultiplicative we obtain several new and known formulas for the determinant and inverse of $(X,Y)_f$ and the usual meet and join matrices $(S)_f$ and $[S]_f$. We also apply these formulas to LCM, MAX, GCD and MIN matrices, which are special cases of join and meet matrices.

  1. Superplasticity and joining of zirconia-based ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez-Rodriguez, A.; Gutierrez-Mora, F.; Jimenez-Melendo, M.; Chaim, R.; Routbort, J. L.

    1999-12-10

    Steady-state creep and joining of alumina/zirconia composites containing alumina volume fractions of 20, 60, and 85% have been investigated between 1,250 and 1,350 C. Superplasticity of these compounds is controlled by grain-boundary sliding and the creep rate is a function of alumina volume fraction, not grain size. Using the principles of superplasticity, pieces of the composite have been joined by applying the stress required to achieve 5 to 10% strain to form a strong interface at temperatures as low as 1,200 C.

  2. Adhesive bonding of composite aircraft structures: Challenges and recent developments

    Science.gov (United States)

    Pantelakis, Sp.; Tserpes, K. I.

    2014-01-01

    In this review paper, the challenges and some recent developments of adhesive bonding technology in composite aircraft structures are discussed. The durability of bonded joints is defined and presented for parameters that may influence bonding quality. Presented is also, a numerical design approach for composite joining profiles used to realize adhesive bonding. It is shown that environmental ageing and pre-bond contamination of bonding surfaces may degrade significantly fracture toughness of bonded joints. Moreover, it is obvious that additional research is needed in order to design joining profiles that will enable load transfer through shearing of the bondline. These findings, together with the limited capabilities of existing non-destructive testing techniques, can partially explain the confined use of adhesive bonding in primary composite aircraft structural parts.

  3. Efficient and scalable graph similarity joins in MapReduce.

    Science.gov (United States)

    Chen, Yifan; Zhao, Xiang; Xiao, Chuan; Zhang, Weiming; Tang, Jiuyang

    2014-01-01

    Along with the emergence of massive graph-modeled data, it is of great importance to investigate graph similarity joins due to their wide applications for multiple purposes, including data cleaning, and near duplicate detection. This paper considers graph similarity joins with edit distance constraints, which return pairs of graphs such that their edit distances are no larger than a given threshold. Leveraging the MapReduce programming model, we propose MGSJoin, a scalable algorithm following the filtering-verification framework for efficient graph similarity joins. It relies on counting overlapping graph signatures for filtering out nonpromising candidates. With the potential issue of too many key-value pairs in the filtering phase, spectral Bloom filters are introduced to reduce the number of key-value pairs. Furthermore, we integrate the multiway join strategy to boost the verification, where a MapReduce-based method is proposed for GED calculation. The superior efficiency and scalability of the proposed algorithms are demonstrated by extensive experimental results.

  4. Social Pharmacy and Clinical Pharmacy - Joining Forces

    DEFF Research Database (Denmark)

    Almarsdottir, Anna Birna; Granas, Anne Gerd

    2016-01-01

    This commentary seeks to define the areas of social pharmacy and clinical pharmacy to uncover what they have in common and what still sets them apart. Common threats and challenges of the two areas are reviewed in order to understand the forces in play. Forces that still keep clinical and social...... pharmacy apart are university structures, research traditions, and the management of pharmacy services. There are key (but shrinking) differences between clinical and social pharmacy which entail the levels of study within pharmaceutical sciences, the location in which the research is carried out...... and external key players in putting forth what is needed for the profession of pharmacy. At the end the question is posed, “What’s in a name?” and we argue that it is important to emphasize what unifies the families of clinical pharmacy and social pharmacy for the benefit of both fields, pharmacy in general...

  5. Joining the Ideational and the Interpersonal Metafunction

    DEFF Research Database (Denmark)

    Holsting, Alexandra

    2013-01-01

    a systemic functional point of view and to demonstrate how the systemic concepts of semantic domain and different linguistic metafunctions, in this case the ideational and the interpersonal, can shed new light on this field. Based on analyses of newspaper examples, it is demonstrated how the resources...... in question are ideational (clause complex, Angle) and interpersonal (modal Adjunct, modal auxiliary, mood) and how they – individually and in combination – emphasize different aspects of projection meaning. A specific status is ascribed to the subjunctive mood, which has a special instructive function...

  6. Joining of SiC ceramics and SiC/SiC composites

    Energy Technology Data Exchange (ETDEWEB)

    Rabin, B.H. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1996-08-01

    This project has successfully developed a practical and reliable method for fabricating SiC ceramic-ceramic joints. This joining method will permit the use of SiC-based ceramics in a variety of elevated temperature fossil energy applications. The technique is based on a reaction bonding approach that provides joint interlayers compatible with SiC, and excellent joint mechanical properties at temperatures exceeding 1000{degrees}C. Recent emphasis has been given to technology transfer activities, and several collaborative research efforts are in progress. Investigations are focusing on applying the joining method to sintered {alpha}-SiC and fiber-reinforced SiC/SiC composites for use in applications such as heat exchangers, radiant burners and gas turbine components.

  7. Joining distributed complex objects: definition and performance

    NARCIS (Netherlands)

    Teeuw, Wouter B.; Blanken, Henk M.

    1992-01-01

    The performance of a non-standard distributed database system is strongly ifluenced by complex objects. The effective exploitation of parallelism in querying them and a suitable structure to store them are required in order to obtain acceptable response times in these database environments where per

  8. Genome aliquoting with double cut and join

    Directory of Open Access Journals (Sweden)

    Sankoff David

    2008-01-01

    Full Text Available Abstract Background The genome aliquoting probem is, given an observed genome A with n copies of each gene, presumed to descend from an n-way polyploidization event from an ordinary diploid genome B, followed by a history of chromosomal rearrangements, to reconstruct the identity of the original genome B'. The idea is to construct B', containing exactly one copy of each gene, so as to minimize the number of rearrangements d(A, B' ⊕ B' ⊕ ... ⊕ B' necessary to convert the observed genome B' ⊕ B' ⊕ ... ⊕ B' into A. Results In this paper we make the first attempt to define and solve the genome aliquoting problem. We present a heuristic algorithm for the problem as well the data from our experiments demonstrating its validity. Conclusion The heuristic performs well, consistently giving a non-trivial result. The question as to the existence or non-existence of an exact solution to this problem remains open.

  9. YAG Laser Face Joining Technology of A6061 Aluminium and SPCC Plates

    Science.gov (United States)

    NISHIMOTO, K.; MARUO, T.; OUMI, M.; SEI, N.; FUJII, H.

    Laser and pressure roll combination joining tests on SPCC-A6061 plates were carried out by changing the roll pressure. Adhesive strengths on SPCC-A6061 were measured by peel tests. When the pressure increased from 80 MPa to 320 MPa, the adhesive strength increased from 10 N/mm to 30 N/mm. It was obvious that the higher pressure brought some good influence to the joint interface of the metals. From observation results on the joint layer by EDX, we recognized ductile compounds Fe3Al and metallic bonds when 320 MPa pressure was laid on by twin rolls. Moreover, it resulted in the achievement of high adhesive strength during the joining of SPCC-A6061 plates.

  10. M2-Edge Colorings Of Cacti And Graph Joins

    Directory of Open Access Journals (Sweden)

    Czap Július

    2016-02-01

    Full Text Available An edge coloring φ of a graph G is called an M2-edge coloring if |φ(v| ≤ 2 for every vertex v of G, where φ(v is the set of colors of edges incident with v. Let 2(G denote the maximum number of colors used in an M2-edge coloring of G. In this paper we determine 2(G for trees, cacti, complete multipartite graphs and graph joins.

  11. Laser -Based Joining of Metallic and Non-metallic Materials

    Science.gov (United States)

    Padmanabham, G.; Shanmugarajan, B.

    Laser as a high intensity heat source can be effectively used for joining of materials by fusion welding and brazing in autogenous or in hybrid modes. In autogenous mode, welding is done in conduction , deep penetration , and keyhole mode. However, due to inherently high energy density available from a laser source, autogenous keyhole welding is the most popular laser welding mode. But, it has certain limitations like need for extremely good joint fit-up, formation of very hard welds in steel , keyhole instability, loss of alloying elements, etc. To overcome these limitations, innovative variants such as laser-arc hybrid welding , induction-assisted welding , dual beam welding , etc., have been developed. Using laser heat, brazing can be performed by melting a filler to fill the joints, without melting the base materials. Accomplishing laser-based joining as mentioned above requires appropriate choice of laser source, beam delivery system, processing head with appropriate optics and accessories. Basic principles of various laser-based joining processes, laser system technology, process parameters, metallurgical effects on different base materials, joint performance, and applications are explained in this chapter.

  12. Perfect state transfer, integral circulants and join of graphs

    CERN Document Server

    Angeles-Canul, Ricardo Javier; Opperman, Michael C; Paribello, Christopher C; Russell, Matthew C; Tamon, Christino

    2009-01-01

    We propose new families of graphs which exhibit quantum perfect state transfer. Our constructions are based on the join operator on graphs, its circulant generalizations, and the Cartesian product of graphs. We build upon the results of Ba\\v{s}i\\'{c} et al \\cite{bps09,bp09} and construct new integral circulants and regular graphs with perfect state transfer. More specifically, we show that the integral circulant $\\textsc{ICG}_{n}(\\{2,n/2^{b}\\} \\cup Q)$ has perfect state transfer, where $b \\in \\{1,2\\}$, $n$ is a multiple of 16 and $Q$ is a subset of the odd divisors of $n$. Using the standard join of graphs, we also show a family of double-cone graphs which are non-periodic but exhibit perfect state transfer. This class of graphs is constructed by simply taking the join of the empty two-vertex graph with a specific class of regular graphs. This answers a question posed by Godsil \\cite{godsil08}.

  13. Bonding and Integration Technologies for Silicon Carbide Based Injector Components

    Science.gov (United States)

    Halbig, Michael C.; Singh, Mrityunjay

    2008-01-01

    Advanced ceramic bonding and integration technologies play a critical role in the fabrication and application of silicon carbide based components for a number of aerospace and ground based applications. One such application is a lean direct injector for a turbine engine to achieve low NOx emissions. Ceramic to ceramic diffusion bonding and ceramic to metal brazing technologies are being developed for this injector application. For the diffusion bonding, titanium interlayers (PVD and foils) were used to aid in the joining of silicon carbide (SiC) substrates. The influence of such variables as surface finish, interlayer thickness (10, 20, and 50 microns), processing time and temperature, and cooling rates were investigated. Microprobe analysis was used to identify the phases in the bonded region. For bonds that were not fully reacted an intermediate phase, Ti5Si3Cx, formed that is thermally incompatible in its thermal expansion and caused thermal stresses and cracking during the processing cool-down. Thinner titanium interlayers and/or longer processing times resulted in stable and compatible phases that did not contribute to microcracking and resulted in an optimized microstructure. Tensile tests on the joined materials resulted in strengths of 13-28 MPa depending on the SiC substrate material. Non-destructive evaluation using ultrasonic immersion showed well formed bonds. For the joining technology of brazing Kovar fuel tubes to silicon carbide, preliminary development of the joining approach has begun. Various technical issues and requirements for the injector application are addressed.

  14. Laser based metal and plastics joining for lightweight design

    Science.gov (United States)

    Kahmann, Max; Quentin, Ulf; Kirchhoff, Marc; Brockmann, Rüdiger; Löffler, Klaus

    2015-03-01

    One of the most important issues in automotive industry is lightweight design, especially since the CO2 emission of new cars has to be reduced by 2020. Plastic and fiber reinforced plastics (e.g. CFRP and GFRP) receive besides new manufacturing methods and the employment of high-strength steels or non-ferrous metals increasing interest. Especially the combination of different materials such as metals and plastics to single components exhausts the entire potential on weight reduction. This article presents an approach based on short laser pulses to join such dissimilar materials in industrial applications.

  15. Joining of Beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, A

    2006-02-01

    A handbook dealing with the many aspects of beryllium that would be important for the users of this metal is currently being prepared. With an introduction on the applications, advantages and limitations in the use of this metal the following topics will be discussed in this handbook: physical, thermal, and nuclear properties; extraction from the ores; purification and casting of ingots; production and types of beryllium powders; consolidation methods, grades, and properties; mechanical properties with emphasis on the various factors affecting these properties; forming and mechanical working; welding, brazing, bonding, and fastening; machining; powder deposition; corrosion; health aspects; and examples of production of components. This report consists of ''Section X--Joining'' from the handbook. The prefix X is maintained here for the figures, tables and references. In this section the different methods used for joining beryllium and the advantages, disadvantages and limitations of each are presented. The methods discussed are fusion welding, brazing, solid state bonding (diffusion bonding and deformation bonding), soldering, and mechanical fastening. Since beryllium has a high affinity for oxygen and nitrogen with the formation of oxides and nitrides, considerable care must be taken on heating the metal, to protect it from the ambient atmosphere. In addition, mating surfaces must be cleaned and joints must be designed to minimize residual stresses as well as locations for stress concentration (notch effects). In joining any two metals the danger exists of having galvanic corrosion if the part is subjected to moisture or to any type of corroding environment. This becomes a problem if the less noble (anodic) metal has a significantly smaller area than the more noble (cathodic) metal since the ions (positive charges) from the anodic (corroding) metal must correspond to the number of electrons (negative charges) involved at the cathode. Beryllium

  16. Joining Forces

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The Chinese and U.S. navies are bound to work together for the common good of the international community Sino-U.S. military relations recently received another boost. The Japan-Ibased U.S. destroyer USS Fitzgerald joined Chinese and foreign naval vessels in a grand international fleet review to celebrate the 60th anniversary of the founding of the Navy of the People’s Liberation Army (PLA) in the coastal city of Qingdao

  17. Phase topography-based characterization of thermal effects on materials and joining techniques.

    Science.gov (United States)

    Lorenz, Hagen; Beckert, Erik; Schödel, René

    2015-03-10

    There are growing demands to characterize the stability of assemblies of optical components for ultrahigh-precision instruments. In this paper we demonstrate how absolute length measurements by interferometry can be applied to measure the thermal and dimensional stability of connections. In order to enable investigation of common joining techniques, including wringing, screwing, and gluing, as well as specialized, inorganic joining techniques such as silicatic bonding, thin-film soldering, and solderjet bumping, representative connections were fabricated. By using gage blocks or prismatic bodies as joining parts, parallelism and flatness were provided which are needed for precision interferometric length measurements. The stability of connection elements used in ultrahigh-precision instruments was investigated longitudinally and laterally to the connection interface, and also mutual tilting of the parts was detected by analysis of the phase topographies. The measurements have an accuracy level of about 1 nm, and the traditional wringing method was also considered as a reference joining technique. The long-term behavior was studied within a period of about 1 year under constant temperature. Further, the thermal dilatation and the reaction of connections to thermal stress were measured. Results show that screwed connections do not exhibit a significant drift of length or orientation. They also did not show response to temperature variations of ±10°C. This is different for adhesive connections, where dimensional changes of up to 100 nm were observed. The specimens produced by using thin-film soldering as well as silicatic bonding revealed stability of length better than 5 nm per year and angular stability within ±0.1   arcsec. Furthermore, these specimens were shown to be insensitive to a temporary temperature variation in a range from 10°C to 40°C. This situation is slightly different for the sample connections produced by solderjet bumping, which show a

  18. DSCu/SS joining techniques development and testing

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Satoshi; Hatano, Toshihisa; Furuya, Kazuyuki; Kuroda, Toshimasa; Enoeda, Mikio; Takatsu, Hideyuki [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1998-01-01

    Joining techniques of alumina dispersion strengthened copper alloy (DSCu) and type 316L stainless steel (SS) has been investigated aiming at applying to the fabrication of the ITER first wall/blanket. As the joining method, Hot Isostatic Pressing (HIP) of solid plates and/or blocks has been pursued. By a screening test including HIP temperatures of 980-1050degC, it was concluded that the HIP temperature of 1050degC would be optimum for the simultaneous HIPping of DSCu/DSCu, DSCu/SS and SS/SS. With DSCu/SS joint specimens HIPped at 1050degC, tensile, impact, fatigue, crack propagation, and fracture toughness tests were performed as well as mechanical test of structural model with one SS circular tube embedded. Typically, the properties of the joints were almost the same as those of DSCu or SS base metal with the same heat treatment of the HIP process, thus good joints were obtained, though parts of properties were decreased at elevated test temperature. Typical results of the mechanical test of structural mode indicated that a crack initiated at the inner surface of the SS tube under cyclic operation, and the lifetime of the first wall structure could be evaluated by existing SS fatigue data. Two HIPped first wall panel mock-ups were successfully fabricated with built-in coolant tubes: one was 300 mm long and the other 800 mm long. The former was thermo-mechanically tested with high heat fluxes corresponding to the ITER operation conditions. The mock-up showed good heat removal performance during the high heat flux tests. In addition, there were no cracks and delaminations found at HIPped interfaces by microscopic observation after all tests. Ultrasonic testing have been tried as a non-destructive examination method, and detectable defect size at SS/SS, DSCu/DSCu and DSCu/SS joint interfaces were estimated. (author)

  19. Joining by plastic deformation

    DEFF Research Database (Denmark)

    Mori, Ken-ichiro; Bay, Niels; Fratini, Livan

    2013-01-01

    opportunities to design new products through joining dissimilar materials. This paper aims to provide an overview of the state of the art in such joining processes, including cold welding, friction stir welding, self-pierce riveting, mechanical clinching and joining by forming. The paper includes description...... of the mechanism of joint formation, and analysis of joint performance and applicability. © 2013 CIRP....

  20. Joining and Integration of Advanced Carbon-Carbon Composites to Metallic Systems for Thermal Management Applications

    Science.gov (United States)

    Singh, M.; Asthana, R.

    2008-01-01

    Recent research and development activities in joining and integration of carbon-carbon (C/C) composites to metals such as Ti and Cu-clad-Mo for thermal management applications are presented with focus on advanced brazing techniques. A wide variety of carbon-carbon composites with CVI and resin-derived matrices were joined to Ti and Cu-clad Mo using a number of active braze alloys. The brazed joints revealed good interfacial bonding, preferential precipitation of active elements (e.g., Ti) at the composite/braze interface. Extensive braze penetration of the inter-fiber channels in the CVI C/C composites was observed. The chemical and thermomechanical compatibility between C/C and metals at elevated temperatures is assessed. The role of residual stresses and thermal conduction in brazed C/C joints is discussed. Theoretical predictions of the effective thermal resistance suggest that composite-to-metal brazed joints may be promising for lightweight thermal management applications.

  1. Comparative analysis of the practice of China and Russia joining the WTO

    OpenAIRE

    Anastasia Sergeyevna Loginova; Liliya Andreevna Travina

    2015-01-01

    Objective to examine the positive and negative experience of China39s joining the World Trade Organization WTO that joined it on terms similar to the Russian ones for the best understanding of the advantages and disadvantages of joining and building the appropriate policy. Methods the objective of the work has been achieved through the application of both general and specific scientific methods. In particular the analysis and synthesis allowed to study the social and economic context...

  2. Ceramic susceptor for induction bonding of metals, ceramics, and plastics

    Science.gov (United States)

    Fox, Robert L.; Buckley, John D.

    1991-01-01

    A thin (.005) flexible ceramic susceptor (carbon) was discovered. It was developed to join ceramics, plastics, metals, and combinations of these materials using a unique induction heating process. Bonding times for laboratory specimens comparing state of the art technology to induction bonding were cut by a factor of 10 to 100 times. This novel type of carbon susceptor allows for applying heat directly and only to the bondline without heating the entire structure, supports, and fixtures of a bonding assembly. The ceramic (carbon film) susceptor produces molten adhesive or matrix material at the bond interface. This molten material flows through the perforated susceptor producing a fusion between the two parts to be joined, which in many instances has proven to be stronger than the parent material. Bonding can be accomplished in 2 minutes on areas submitted to the inductive heating. Because a carbon susceptor is used in bonding carbon fiber reinforced plastics and ceramics, there is no radar signature or return making it an ideal process for joining advanced aerospace composite structures.

  3. Efficient string similarity join in multi-core and distributed systems.

    Science.gov (United States)

    Yan, Cairong; Zhao, Xue; Zhang, Qinglong; Huang, Yongfeng

    2017-01-01

    In big data area a significant challenge about string similarity join is to find all similar pairs more efficiently. In this paper, we propose a parallel processing framework for efficient string similarity join. First, the input is split into some disjoint small subsets according to the joint frequency distribution and the interval distribution of strings. Then the filter-verification strategy is adopted in the computation of string similarity for each subset so that the number of candidate pairs is reduced before an effective pruning strategy is used to improve the performance. Finally, the operation of string join is executed in parallel. Para-Join algorithm based on the multi-threading technique is proposed to implement the framework in a multi-core system while Pada-Join algorithm based on Spark platform is proposed to implement the framework in a cluster system. We prove that Para-Join and Pada-Join cannot only avoid reduplicate computation but also ensure the completeness of the result. Experimental results show that Para-Join can achieve high efficiency and significantly outperform than state-of-the-art approaches, meanwhile, Pada-Join can work on large datasets.

  4. Predictive modeling of reactive wetting and metal joining.

    Energy Technology Data Exchange (ETDEWEB)

    van Swol, Frank B.

    2013-09-01

    The performance, reproducibility and reliability of metal joints are complex functions of the detailed history of physical processes involved in their creation. Prediction and control of these processes constitutes an intrinsically challenging multi-physics problem involving heating and melting a metal alloy and reactive wetting. Understanding this process requires coupling strong molecularscale chemistry at the interface with microscopic (diffusion) and macroscopic mass transport (flow) inside the liquid followed by subsequent cooling and solidification of the new metal mixture. The final joint displays compositional heterogeneity and its resulting microstructure largely determines the success or failure of the entire component. At present there exists no computational tool at Sandia that can predict the formation and success of a braze joint, as current capabilities lack the ability to capture surface/interface reactions and their effect on interface properties. This situation precludes us from implementing a proactive strategy to deal with joining problems. Here, we describe what is needed to arrive at a predictive modeling and simulation capability for multicomponent metals with complicated phase diagrams for melting and solidification, incorporating dissolutive and composition-dependent wetting.

  5. Microstructure and properties of ceramics and composites joined by plastic deformation.

    Energy Technology Data Exchange (ETDEWEB)

    Goretta, K. C.; Singh, D.; Chen, N.; Gutierrez-Mora, F.; Lorenzo-Martin, M. de la, Cinta; Dominguez-Rodriguez, A.; Routbort, J. L.; Energy Systems; Univ. of Seville

    2008-12-01

    A review is presented of the design of suitable materials systems for joining by high-temperature plastic deformation, details of the joining techniques, microstructures and properties of the resulting composite bodies, and prospects and limitation for this type of joining technology. Joining parameters and resulting forms are discussed for Al{sub 2}O{sub 3}/mullite particulate composites, Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} particulate/Al{sub 2}O{sub 3} particulate and whisker-reinforced composites, hydroxyapatite bioceramics, La{sub 0.85}Sr{sub 0.15}MnO{sub 3} electronic ceramics, MgF{sub 2} optical ceramics, and Ni{sub 3}Al intermetallics. Results are contrasted with those obtained by other methods of joining brittle, high-temperature materials, with special focus on durability and mechanical properties.

  6. Microstructure and properties of ceramics and composites joined by plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Goretta, K.C. [Argonne National Laboratory, Argonne, IL 60439-4838 (United States)], E-mail: ken.goretta@aoard.af.mil; Singh, D.; Chen Nan [Argonne National Laboratory, Argonne, IL 60439-4838 (United States); Gutierrez-Mora, F.; Cinta Lorenzo-Martin, M. de la [Argonne National Laboratory, Argonne, IL 60439-4838 (United States); University of Seville, Seville 41080 (Spain); Dominguez-Rodriguez, A. [University of Seville, Seville 41080 (Spain); Routbort, J.L. [Argonne National Laboratory, Argonne, IL 60439-4838 (United States)

    2008-12-20

    A review is presented of the design of suitable materials systems for joining by high-temperature plastic deformation, details of the joining techniques, microstructures and properties of the resulting composite bodies, and prospects and limitation for this type of joining technology. Joining parameters and resulting forms are discussed for Al{sub 2}O{sub 3}/mullite particulate composites, Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} particulate/Al{sub 2}O{sub 3} particulate and whisker-reinforced composites, hydroxyapatite bioceramics, La{sub 0.85}Sr{sub 0.15}MnO{sub 3} electronic ceramics, MgF{sub 2} optical ceramics, and Ni{sub 3}Al intermetallics. Results are contrasted with those obtained by other methods of joining brittle, high-temperature materials, with special focus on durability and mechanical properties.

  7. Meet and Join Matrices in the Poset of Exponential Divisors

    Indian Academy of Sciences (India)

    Ismo Korkee; Pentti Haukkanen

    2009-06-01

    It is well-known that $(\\mathbb{Z}_+,|)=(\\mathbb{Z}_+,GCD,LCM)$ is a lattice, where $|$ is the usual divisibility relation and $GCD$ and $LCM$ stand for the greatest common divisor and the least common multiple of positive integers. The number $d=\\prod^r_{k=1}p^{d^{(k)}}_k$ is said to be an exponential divisor or an -divisor of $n=\\prod^r_{k=1}p^{n^{(k)}}_k(n >1)$, written as $d|_e n$, if $d^{(k)}|n^{(k)}$ for all prime divisors $p_k$ of . It is easy to see that $(\\mathbb{Z}_+\\backslash\\{1\\},|_e)$ is a poset under the exponential divisibility relation but not a lattice, since the greatest common exponential divisor $(GCED)$ and the least common exponential multiple $(LCEM)$ do not always exist. In this paper we embed this poset in a lattice. As an application we study the $GCED$ and $LCEM$ matrices, analogues of $GCD$ and $LCM$ matrices, which are both special cases of meet and join matrices on lattices.

  8. AN ABSTRACT RELATIONAL MODEL AND NATURAL JOIN FUNCTORS

    OpenAIRE

    Kato, Akihiko

    1983-01-01

    A meta-model for database models called an abstract relational model which is obtained by a categorical abstraction of a relational model is proposed. This meta-model represents various database models, e.g. relational, network, hierarchical models as special cases. It is proved that a natural join is the right adjoint of a decomposition in the relational model. On the other hand, in our abstract relational model a natural join is defined as the right adjoint of a decomposition. A sufficient ...

  9. Safe and Liquid Mortgage Bonds

    DEFF Research Database (Denmark)

    Dick-Nielsen, Jens; Gyntelberg, Jacob; Lund, Jesper

    This paper shows that strict match pass-through funding of covered bonds provides safe and liquid mortgage bonds. Despite a 30% drop in house prices during the 2008 global crisis Danish mortgage bonds remained as liquid as most European government bonds. The Danish pass-through system effectively...... eliminates credit risk from the investor's perspective. Similar to other safe bonds, funding liquidity becomes the main driver of mortgage bond liquidity and this creates commonality in liquidity across markets and countries. These findings have implications for how to design a robust mortgage bond system...

  10. Effect of ultrasonic power and bonding force on the bonding strength of copper ball bonds

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Copper wire, serving as a cost-saving alternative to gold wire, has been used in many high-end thermosonic ball bonding applications. In this paper, the bond shear force, bond shear strength, and the ball bond diameter are adopted to evaluate the bonding quality. It is concluded that the efficient ultrasonic power is needed to soften the ball to form the copper bonds with high bonding strength. However, excessive ultrasonic power would serve as a fatigue loading to weaken the bonding. Excessive or less bonding force would cause cratering in the silicon.

  11. Realizing joined-up government: Dynamic capabilities and stage models for transformation

    NARCIS (Netherlands)

    Klievink, B.; Janssen, M.

    2009-01-01

    Joining up remains a high priority on the e-government agenda and requires extensive transformation. Stage models are predictable patterns which exist in the growth of organizations and unfold as discrete time periods that result in discontinuity and can help e-government development towards joined-

  12. Robust Joining and Assembly of Ceramic Matrix Composites for High Temperature Applications

    Science.gov (United States)

    Singh, Mrityunjay

    2003-01-01

    Advanced ceramic matrix composites (CMCs) are under active consideration for use in a wide variety of high temperature applications within the aerospace, energy, and nuclear industries. The engineering designs of CMC components require fabrication and manufacturing of large and complex shaped parts of various thicknesses. In many instances, it is more economical to build up complex shapes by joining simple geometrical shapes. Thus, joining and attachment have been recognized as enabling technologies for successful utilization of ceramic components in various demanding applications. In this presentation, various challenges and opportunities in design, fabrication, and testing of high temperature joints in ceramic matrix composites will be presented. A wide variety of ceramic composites, in different shapes and sizes, have been joined using an affordable, robust ceramic joining technology (ARCJoinT). Microstructure and mechanical properties of joints in melt infiltrated and CVI Sic matrix composites will be reported. Various joint design philosophies and design issues in joining of composites will be discussed.

  13. Joining and Assembly of Bulk Metallic Glass Composites Through Capacitive Discharge

    Science.gov (United States)

    Hofmann, Douglas C.; Roberts, Scott; Kozachkov, Henry; Demetriou, Marios D.; Schramm, Joseph P.; Johnson, William L.

    2012-01-01

    Bulk metallic glasses (BMGs), a class of amorphous metals defined as having a thickness greater than 1 mm, are being broadly investigated by NASA for use in spacecraft hardware. Their unique properties, attained from their non-crystalline structure, motivate several game-changing aerospace applications. BMGs have low melting temperatures so they can be cheaply and repeatedly cast into complex net shapes, such as mirrors or electronic casings. They are extremely strong and wear-resistant, which motivates their use in gears and bearings. Amorphous metal coatings are hard, corrosion-resistant, and have high reflectivity. BMG composites, reinforced with soft second phases, can be fabricated into energy-absorbing cellular panels for orbital debris shielding. One limitation of BMG materials is their inability to be welded, bonded, brazed, or fastened in a convenient method to form larger structures. Cellular structures (which can be classified as trusses, foams, honeycombs, egg boxes, etc.) are useful for many NASA, commercial, and military aerospace applications, including low-density paneling and shields. Although conventional cellular structures exhibit high specific strength, their porous structures make them challenging to fabricate. In particular, metal cellular structures are extremely difficult to fabricate due to their high processing temperatures. Aluminum honeycomb sandwich panels, for example, are used widely as spacecraft shields due to their low density and ease of fabrication, but suffer from low strength. A desirable metal cellular structure is one with high strength, combined with low density and simple fabrication. The thermoplastic joining process described here allows for the fabrication of monolithic BMG truss-like structures that are 90% porous and have no heat-affected zone, weld, bond, or braze. This is accomplished by welding the nodes of stacked BMG composite panels using a localized capacitor discharge, forming a single monolithic structure

  14. Hydrogen bond and halogen bond inside the carbon nanotube

    Science.gov (United States)

    Wang, Weizhou; Wang, Donglai; Zhang, Yu; Ji, Baoming; Tian, Anmin

    2011-02-01

    The hydrogen bond and halogen bond inside the open-ended single-walled carbon nanotubes have been investigated theoretically employing the newly developed density functional M06 with the suitable basis set and the natural bond orbital analysis. Comparing with the hydrogen or halogen bond in the gas phase, we find that the strength of the hydrogen or halogen bond inside the carbon nanotube will become weaker if there is a larger intramolecular electron-density transfer from the electron-rich region of the hydrogen or halogen atom donor to the antibonding orbital of the X-H or X-Hal bond involved in the formation of the hydrogen or halogen bond and will become stronger if there is a larger intermolecular electron-density transfer from the electron-rich region of the hydrogen or halogen atom acceptor to the antibonding orbital of the X-H or X-Hal bond. According to the analysis of the molecular electrostatic potential of the carbon nanotube, the driving force for the electron-density transfer is found to be the negative electric field formed in the carbon nanotube inner phase. Our results also show that the X-H bond involved in the formation of the hydrogen bond and the X-Hal bond involved in the formation of the halogen bond are all elongated when encapsulating the hydrogen bond and halogen bond within the carbon nanotube, so the carbon nanotube confinement may change the blue-shifting hydrogen bond and the blue-shifting halogen bond into the red-shifting hydrogen bond and the red-shifting halogen bond. The possibility to replace the all electron nanotube-confined calculation by the simple polarizable continuum model is also evaluated.

  15. Common Influence Join

    DEFF Research Database (Denmark)

    Yiu, Man Lung; Mamoulis, Nikos; Karras, Panagiotis

    2008-01-01

    We identify and formalize a novel join operator for two spatial pointsets P and Q. The common influence join (CIJ) returns the pairs of points (p,q),p isin P,q isin Q, such that there exists a location in space, being closer to p than to any other point in P and at the same time closer to q than...

  16. Simulation of a Novel Joining Process for Fiber-Reinforced Thermoplastic Composites and Metallic Components

    Science.gov (United States)

    Gude, M.; Freund, A.; Vogel, C.; Kupfer, R.

    2017-01-01

    In this study, a new joining technology to produce hybrid structures with continuous-fiber-reinforced thermoplastics and metallic components is presented adapting the concept of classical clinching for thermoplastic composites. To demonstrate the capability of the thermoclinching process, prototypic joints were manufactured using an experimental joining installation developed. Nondestructive and destructive analyses of the thermoclinched joints showed that a relocation of the reinforcement into the neck and head area of the joining zone could be achieved. For a first estimation of the maximum load-carrying capacity of the joints, single-lap specimens with both reinforced and nonreinforced thermoplastics were manufactured and tested, revealing up to 50% higher failure loads of the reinforced joints. To understand the local material configuration and to achieve a defined and adjustable fabric structure in the head area of the joint, further analyses with regard to material- and tool-side conditions of the joining zone are necessary.

  17. Trading in Treasury Bond Futures Contracts and Bonds in Australia

    OpenAIRE

    Belinda Cheung

    2014-01-01

    Treasury bond futures are a key financial product in Australia, with turnover in Treasury bond futures contracts significantly larger than turnover in the market for Commonwealth Government securities (CGS). Treasury bond futures contracts provide a wide variety of market participants with the ability to hedge against, or gain exposure to, interest rate risk. This article discusses some of the features of the Treasury bond futures contract, and how the contract is used to facilitate hedging a...

  18. When and Whom to Join: The Expansion of Ongoing Violent Interstate Conflicts

    OpenAIRE

    Bayer, Reşat; Joyce, Kyle A.; Ghosn, Faten

    2014-01-01

    The opportunity and willingness framework has received much attention in research on interstate conflict expansion. This framework is extended here by examining when and what side third parties join during ongoing conflicts. It is maintained that without examining both timing and side selection, understanding of conflict expansion is limited. The timing and side joined in interstate disputes between 1816 and 2001 are analysed using a competing risks duration model. The findings contribute nov...

  19. Parcels and Land Ownership, had to join to cama database, Published in 2008, Campbell County Government.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Parcels and Land Ownership dataset as of 2008. It is described as 'had to join to cama database'. The extent of these data is generally Campbell County, WY....

  20. Kyrgyz Republic - The Garment Sector : Impact of Joining the Customs Union and Options to Increase Competitiveness

    OpenAIRE

    World Bank

    2014-01-01

    This note analyzes the impact that joining the Eurasian Customs Union will have on the Kyrgyz Republic s garment sector and options for improving the sector s competitiveness. The paper finds that joining the Eurasian Customs Union will lead to higher prices for the textiles and cloth used in garment production. This will increase the cost of producing garments in the Kyrgyz Republic and w...

  1. Advanced joining techniques for modern lightweight steel construction; Techniques d`assemblage des aciers a haute resistance pour vehicule leger

    Energy Technology Data Exchange (ETDEWEB)

    Stegemann, T. [Thyssen Stahl AG, Duisburg (Germany); Hahn, O.; Schulte, A. [Paderborn Univ. (Gesamthochschule) (Germany)

    1998-01-01

    New high-strength steel grades in combination with modern joining techniques contribute to optimize properties of the joints. Specially heatless joining techniques improve the fatigue properties of the joints as well as the crash behaviour. Such mechanical joining techniques are clinching and self piercing riveting. But the combined joining techniques e.g., weld bonding, clinching combined with bonding are also effective in the case of high-strength steel sheets. The minor heat input of laser-beam welds can also be used to join high strength steels to stiffer light weight structures. (authors)

  2. Recombination, transcription, and diversity of a partially germline-joined VH in a mammal.

    Science.gov (United States)

    Wang, Xinxin; Miller, Robert D

    2012-09-01

    Full or partially germline-joined V genes have been described in a number of different vertebrate lineages where they can contribute to the expressed antibody repertoire through different mechanisms. Here we demonstrate that VH3.1, a partially germline-joined VH gene in the opossum Monodelphis domestica, can undergo V(D)J recombination to generate productive IgH transcripts. VH3.1 is fused to a DH gene segment in the germline DNA and is the only known example of a germline-joined VH in a mammal. B cells that have recombined VH3.1 were not detected until nearly 2 months of age, around the time of weaning, and much later than B cells using the conventional VH. Compared to opossum IgH transcripts using the conventional VH genes, those with VH3.1 have unusually long CDR3 due to the length of the germline-joined DH.

  3. Joining of 14YWT and F82H by friction stir welding

    Energy Technology Data Exchange (ETDEWEB)

    Hoelzer, D.T., E-mail: hoelzerd@ornl.gov; Unocic, K.A.; Sokolov, M.A.; Feng, Z.

    2013-11-15

    Friction stir welding was investigated for joining specimens of the ODS 14YWT ferritic alloy together and to an F82H tempered martensitic steel plate. The FSW run was performed using a polycrystalline boron nitride tool and resulted in good bonding between 14YWT/14YWT and 14YWT/F82H. Joints and interfaces were observed by light microscopy and SEM analysis to be narrow in width. The ultra-small grain size of 14YWT increased by a factor up to 4 while that of F82H decreased by a considerable amount in the weld zones. The TEM analysis showed no significant changes in the size of the oxygen-enriched nanoclusters in the weld zone of 14YWT. However, defects such as a wormhole on the advancing side of the weld zone in 14YWT and small pores associated with joints and interfaces were observed in the FSW sample. The hardness measurements from unaffected zone into weld zones showed ∼20% decrease in hardness for 14YWT (from ∼500 VH to ∼380 VH) and ∼100% increase in hardness of F82H (from ∼220 VH to ∼440 VH)

  4. Human transcriptional coactivator PC4 stimulates DNA end joining and activates DSB repair activity.

    Science.gov (United States)

    Batta, Kiran; Yokokawa, Masatoshi; Takeyasu, Kunio; Kundu, Tapas K

    2009-01-23

    Human transcriptional coactivator PC4 is a highly abundant nuclear protein that is involved in diverse cellular processes ranging from transcription to chromatin organization. Earlier, we have shown that PC4, a positive activator of p53, overexpresses upon genotoxic insult in a p53-dependent manner. In the present study, we show that PC4 stimulates ligase-mediated DNA end joining irrespective of the source of DNA ligase. Pull-down assays reveal that PC4 helps in the association of DNA ends through its C-terminal domain. In vitro nonhomologous end-joining assays with cell-free extracts show that PC4 enhances the joining of noncomplementary DNA ends. Interestingly, we found that PC4 activates double-strand break (DSB) repair activity through stimulation of DSB rejoining in vivo. Together, these findings demonstrate PC4 as an activator of nonhomologous end joining and DSB repair activity.

  5. A Review of Similar and Dissimilar Micro-joining of Nitinol

    Science.gov (United States)

    Deepan Bharathi Kannan, T.; Ramesh, T.; Sathiya, P.

    2016-04-01

    NiTinol belongs to a class of smart materials which has a wide range of applications in the field of automotive, aerospace, biomedical, robotics, etc., owing to the growing trend in miniaturization of components. Micro-joining is becoming one of the important and familiar processes in the fabrication of miniaturized components. Recently, effective micro-joining of thin sheets has been gaining a lot of interest among researchers. In this article, the research and progress in micro-joining of NiTinol to itself and other metals are reviewed at different aspects. To date, laser welding, tungsten inert gas welding, and resistance welding have been used to a large extent in investigating the weldability of NiTinol alloys. Some important welding parameters used in micro joining by various researchers and their effects on weld qualities are detailed in this review. Metallurgical aspects, mechanical properties and corrosion aspects of micro-joined NiTinol sheets/wires are discussed. The aim of this report is to review the recent progress in micro-joining of NiTinol and to provide a basis for follow-on research.

  6. Electron beam joining of structural ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Turman, B.N.; Glass, S.J.; Halbleib, J.A.; Helmich, D.R.; Loehman, R.E.

    1995-04-01

    Feasibility of ceramic joining using a high energy (10 MeV) electron beam. The experiments used refractory metals as bonding materials in buried interfaces between Si{sub 3}N{sub 4} pieces. Because the heat capacity of the metal bonding layer is much lower than the ceramic, the metal reaches much higher temperatures than the adjoining ceramic. Using the right combination of beam parameters allows the metal to be melted without causing the adjoining ceramics to melt or decompose. Beam energy deposition and thermal simulations were performed to guide the experiments. Joints were shear tested and interfaces between the metal and the ceramic were examined to identify the bonding mechanism. Specimens joined by electron beams were compared to specimens produced by hot-pressing. Similar reactions occurred using both processes. Reactions between the metal and ceramic produced silicides that bond the metal to the ceramic. The molybdenum silicide reaction products appeared to be more brittle than the platinum silicides. Si{sub 3}N{sub 4} was also joined to Si{sub 3} N{sub 4} directly. The bonding appears to have been produced by the flow of intergranular glass into the interface. Shear strength was similar to the metal bonded specimens. Bend specimens Of Si{sub 3}N{sub 4} were exposed to electron beams with similar parameters to those used in joining experiments to determine how beam exposure degrades the strength. Damage was macroscopic in nature with craters being tonned by material ablation, and cracking occurring due to excessive thermal stresses. Si was also observed on the surface indicating the Si{sub 3}N{sub 4} was decomposing. Bend strength after exposure was 62% of the asreceived strength. No obvious microstructural differences were observed in the material close to the damaged region compared to material in regions far away from the damage.

  7. TIG and HIP joining of Reduced Activation Ferrite/Martensitic steel for the Korean ITER-TBM

    Energy Technology Data Exchange (ETDEWEB)

    Ku, Duck Young [ITER Korea, National Fusion Research Institute, Gwahangno 113, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Oh, Seungjin, E-mail: osj0423@gmail.com [Nuclear Engineering and Technology Institute, KHNP, 508 Keumbyeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Ahn, Mu-Young; Yu, In-Keun; Kim, Duck-Hoi; Cho, Seungyon [ITER Korea, National Fusion Research Institute, Gwahangno 113, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Choi, Im-Sub; Kwon, Ki-Bum [Soles Co. LTD., 9-1 Horim-dong, Dalseo-gu, Daegu 704-249 (Korea, Republic of)

    2011-10-01

    Korea is developing a Helium Cooled Solid Breeder Test Blanket Module for ITER. The primary candidate structural material is a Reduced Activation Ferritic/Martensitic steel. The complex TBM structure requires developing joining technologies for successful fabrication. The characteristics of Tungsten Inert Gas welding and Hot Isostatic Pressing joining of RAFM steel were investigated. Metallurgical examinations showed that the steel grain size was increased after HIP joining and recovered by post joining heat treatment. Both TIG welding and HIP joining are found to be acceptable for ITER TBM based on mechanical tests and microstructure examination.

  8. Comparative analysis of the practice of China and Russia joining the WTO

    Directory of Open Access Journals (Sweden)

    Anastasia Sergeyevna Loginova

    2015-09-01

    Full Text Available Objective to examine the positive and negative experience of China39s joining the World Trade Organization WTO that joined it on terms similar to the Russian ones for the best understanding of the advantages and disadvantages of joining and building the appropriate policy. Methods the objective of the work has been achieved through the application of both general and specific scientific methods. In particular the analysis and synthesis allowed to study the social and economic context of the state in the framework of joining the WTO the consequences of such membership and to identify the key areas for improvement of this step for Russia. Statistical techniques were used in the process of gathering information about the key economic indicators. The fundamental method was comparativelegal which made it possible to draw parallels in joining the WTO by various states. Results basing on the measures taken by China both before and after joining the WTO as well as evaluation of their implication the conclusion was made about its successful experience. The actions before joining were very effective. In particular they are applicable to the fields of agriculture automotive industry investment policy etc. The measures of nonaddress subsidizing maintaining the socioeconomic stability in the country the export orientation of the economy along with functioning of special economic zones with joint ventures are in the authors39 opinion constructive actions for Russiarsquos adaptation to the WTO. Scientific novelty for the first time the thesis is put forward about the similarity of the Russia and China conditions when joining the WTO. The analysis is made of the complex measures preceding and following the joining. The necessity is grounded of reflecting the China39s positive and negative experiences in the Russian policy. Practical significance the main provisions and conclusions can be used in the research activity in addressing the issues of Russiarsquos

  9. Adhesive Bonding of Aluminium Alloy A5754 by Epoxy Resins

    Directory of Open Access Journals (Sweden)

    Ivan Michalec

    2013-01-01

    Full Text Available Joining thin sheets of aluminium and its alloys is a promising area in the field of joining materials. Nowadays, joining methods that do not melt the material itself are increasingly being utilised. This paper deals with adhesive bonding of aluminium alloy A5754 by two-component epoxy resins. Theresults show that joints bonded by Hysol 9466 have appropriate mechanical properties, but that joints bonded by Hysol 9492 have better thermal stability.

  10. Bond strength of direct and indirect bonded brackets after thermocycling.

    Science.gov (United States)

    Daub, Jacob; Berzins, David W; Linn, Brandon James; Bradley, Thomas Gerard

    2006-03-01

    Thermocycling simulates the temperature dynamics in the oral environment. With direct bonding, thermocycling reduces the bond strength of orthodontic adhesives to tooth structure. The purpose of this study was to evaluate the shear bond strengths (SBS) of one direct and two indirect bonding methods/adhesives after thermocycling. Sixty human premolars were divided into three groups. Teeth in group 1 were bonded directly with Transbond XT. Teeth in group 2 were indirect bonded with Transbond XT/Sondhi Rapid Set, which is chemically cured. Teeth in group 3 were indirect bonded with Enlight LV/Orthosolo and light cured. Each sample was thermocycled between 5 degrees C and 55 degrees C for 500 cycles. Mean SBS in groups 1, 2, and 3 were not statistically significantly different (13.6 +/- 2.9, 12.3 +/- 3.0, and 11.6 +/- 3.2 MPa, respectively; P > .05). However, when these values were compared with the results of a previous study using the same protocol, but without thermocycling, the SBS was reduced significantly (P = .001). Weibull analysis further showed that group 3 had the lowest bonding survival rate at the minimum clinically acceptable bond-strength range. The Adhesive Remnant Index was also determined, and group 2 had a significantly (P bond failures at the resin/enamel interface.

  11. Wafer bonding applications and technology

    CERN Document Server

    Gösele, Ulrich

    2004-01-01

    During the past decade direct wafer bonding has developed into a mature materials integration technology. This book presents state-of-the-art reviews of the most important applications of wafer bonding written by experts from industry and academia. The topics include bonding-based fabrication methods of silicon-on-insulator, photonic crystals, VCSELs, SiGe-based FETs, MEMS together with hybrid integration and laser lift-off. The non-specialist will learn about the basics of wafer bonding and its various application areas, while the researcher in the field will find up-to-date information about this fast-moving area, including relevant patent information.

  12. Pulse joining cartridges

    Energy Technology Data Exchange (ETDEWEB)

    Golovashchenko, Sergey Fedorovich; Bonnen, John Joseph Francis

    2016-08-23

    A pulsed joining tool includes a tool body that defines a cavity that receives an inner tubular member and an outer tubular member and a pulse joining cartridge. The tubular members are nested together with the cartridge being disposed around the outer tubular member. The cartridge includes a conductor, such as a wire or foil, that extends around the outer tubular member and is insulated to separate a supply segment from a return segment. A source of stored electrical energy is discharged through the conductor to join the tubular members with an electromagnetic force pulse.

  13. Toroid Joining Gun. [thermoplastic welding system using induction heating

    Science.gov (United States)

    Buckley, J. D.; Fox, R. L.; Swaim, R J.

    1985-01-01

    The Toroid Joining Gun is a low cost, self-contained, portable low powered (100-400 watts) thermoplastic welding system developed at Langley Research Center for joining plastic and composite parts using an induction heating technique. The device developed for use in the fabrication of large space sructures (LSST Program) can be used in any atmosphere or in a vacuum. Components can be joined in situ, whether on earth or on a space platform. The expanded application of this welding gun is in the joining of thermoplastic composites, thermosetting composites, metals, and combinations of these materials. Its low-power requirements, light weight, rapid response, low cost, portability, and effective joining make it a candidate for solving many varied and unique bonding tasks.

  14. Innovative cold joining technologies based on tube forming

    Directory of Open Access Journals (Sweden)

    Alves Luis M.

    2015-01-01

    Full Text Available This paper is focused on innovative cold joining technologies for connecting tubes and fixing tubes to sheets. The proposed technologies are based on the utilization of plastic instability waves in thin-walled tubes subjected to axial compression and may be seen as an alternative to conventional joining technologies based on mechanical fixing with fasteners, welding and structural adhesive bonding. Besides allowing connecting dissimilar materials and being successfully employed in fixture conditions that are difficult and costly to achieve by means of conventional joining the new proposed technologies also cope with the growing concerns on the demand, lifecycle and recycling of materials.

  15. Thin layer joining by gas adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Taga, Yasunori, E-mail: y-taga@isc.chubu.ac.jp; Fukumura, Toshio

    2014-10-01

    Highlights: • We report thin layer molecular joining between glass and COP by gas adsorption. Thickness of joining layer is 1–2 nm and joining process was carried out at low temperature at about 100 °C. • Adhesion strength measured by 180 degree peel test revealed to be 1–10 N/25 mm and the joined stack showed high durability for practical use. - Abstract: Attempt has been made to join borosilicate glass and cycloolefin (COP) polymer film by using gas adsorption method. After corona plasma treat, COP was exposed to (3-glycidoxypropyl) trimethoxysilane (GPS) and glass to (3-aminopropyl) triethoxysilane (APS) both in air atmosphere, resulting in co-adsorption of water vapor in the atmosphere and organosilane gases. Surface characterization of plasma treated and gas adsorbed surfaces was carried out by X-ray photoelectron spectroscopy (XPS) using Mg Kα X-ray source. Joining was carried out by a roll laminator after contact of both surfaces at room temperature, followed by annealing at 130 °C for 10 min. Adhesion strength was evaluated by 180 degree peel test based on ASTM D-903 and durability was examined under the conditions of 60 °C and 95% RH. It was found that after plasma treatment, complex functional groups such as C-H, C-O, C=O, O-C=O and CO{sub 3} were found on COP and O-H on glass. Thickness of GPS gas adsorption layer on COP was evaluated by the XPS to be at least 1.1 nm by taking inelastic mean free path of Si{sub 2p} photoelectron into consideration. Joining force was found to be more than 5 N/25 mm corresponding to almost equal to COP bulk tensile strength. In addition, durability of this adhesion strength remained unchanged over 2000 h even after exposure to the durability test conditions of 60 °C and 95% RH. The results can be explained in terms of formation of H-H hydrogen bonding and Si-O covalent bonding via silanols will be made at the interface as a result of lamination and annealing processes. In conclusion, ultrathin joining method

  16. References and arrow notation instead of join operation in query languages

    Directory of Open Access Journals (Sweden)

    Alexandr Savinov

    2012-10-01

    Full Text Available We study properties of the join operation in query languages and describe some of its major drawbacks. We provide strong arguments against using joins as a main construct for retrieving related data elements in general purpose query languages and argue for using references instead. Since conventional references are quite restrictive when applied to data modeling and query languages, we propose to use generalized references as they are defined in the concept-oriented model (COM. These references are used by two new operations, called projection and de-projection, which are denoted by right and left arrows and therefore this access method is referred to as arrow notation. We demonstrate advantages of the arrow notation in comparison to joins and argue that it makes queries simpler, more natural, easier to understand, and the whole query writing process more productive and less error-prone.

  17. Comparison of Bond in Roll-bonded and Adhesively Bonded Aluminums

    Science.gov (United States)

    Schwensfeir, R. J., Jr.; Trenkler, G.; Delagi, R. G.; Forster, J. A.

    1985-01-01

    Lap-shear and peel test measurements of bond strength have been carried out as part of an investigation of roll bonding of 2024 and 7075 aluminum alloys. Shear strengths of the bonded material in the F temper are in the range of 14 to 16 ksi. Corresponding peel strengths are 120 to 130 lb/inch. These values, which are three to five times those reported in the literature for adhesively bonded 2024 and 7075, are a result of the true metallurgical bond achieved. The effects of heat-treating the bonded material are described and the improvements in bond strength discussed relative to the shear strength of the parent material. The significance of the findings for aerospace applications is discussed.

  18. Weld bonding of stainless steel

    DEFF Research Database (Denmark)

    Santos, I. O.; Zhang, Wenqi; Goncalves, V.M.

    2004-01-01

    This paper presents a comprehensive theoretical and experimental investigation of the weld bonding process with the purpose of evaluating its relative performance in case of joining stainless steel parts, against alternative solutions based on structural adhesives or conventional spot...

  19. Effects of bonding temperature on microstructure, fracture behavior and joint strength of Ag nanoporous bonding for high temperature die attach

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min-Su, E-mail: mskim927@gmail.com [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nishikawa, Hiroshi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2015-10-01

    Ag nanoparticle sintering has received much attention as an alternative joining method to lead-based soldering for high temperature electronic applications. However, there are still certain issues with this method, such as difficulties of in controlling the joining layer thickness and the occurrence of unexpected voids resulting from solvent evaporation. In this study, the effect of bonding temperature (200–400 °C) and environment (air and N{sub 2}) on the joint strength of Ag nanoporous bonding (NPB) on electroless nickel/immersion gold finished Cu disks was investigated. A nanoporous Ag sheet fabricated using dealloying method from an Al–Ag precursor was adopted as the insert material. The NPB was conducted at various temperatures (200–400 °C) for 30 min at a pressure of 20 MPa in both air and N{sub 2} environments. The joint strength of NPB was closely related with the microstructure of the Ag layer and the fracture mode of the joint, and increased with increasing bonding temperature through the formation of strong interface and a coarsened Ag layer. The effect of the bonding environment was not significant, except in the case of bonding temperature of 400 °C.

  20. Using Negotiated Joining to Construct and Fill Open-ended Roles in Elite Culinary Groups.

    Science.gov (United States)

    Tan, Vaughn

    2015-03-01

    This qualitative study examines membership processes in groups operating in an uncertain environment that prevents them from fully predefining new members' roles. I describe how nine elite high-end, cutting-edge culinary groups in the U.S. and Europe, ranging from innovative restaurants to culinary R&D groups, use negotiated joining-a previously undocumented process-to systematically construct and fill these emergent, open-ended roles. I show that negotiated joining is a consistently patterned, iterative process that begins with a role that both aspirant and target group explicitly understand to be provisional. This provisional role is then jointly modified and constructed by the aspirant and target group through repeated iterations of proposition, validation through trial and evaluation, and selective integration of validated role components. The initially provisional role stabilizes and the aspirant achieves membership if enough role components are validated; otherwise the negotiated joining process is abandoned. Negotiated joining allows the aspirant and target group to learn if a mutually desirable role is likely and, if so, to construct such a role. In addition, the provisional roles in negotiated joining can support absorptive capacity by allowing novel role components to enter target groups through aspirants' efforts to construct stable roles for themselves, while the internal adjustment involved in integrating newly validated role components can have the unintended side effect of supporting adaptation by providing opportunities for the groups to use these novel role components to modify their role structure and goals to suit a changing and uncertain environment. Negotiated joining thus reveals role ambiguity's hitherto unexamined beneficial consequences and provides a foundation for a contingency theory of new-member acquisition.

  1. Exploring the Split and Join Capabilities of a Robotic Collective Movement Framework

    Directory of Open Access Journals (Sweden)

    Iñaki Navarro

    2013-05-01

    Full Text Available The splitting and joining capabilities of a previously designed framework for the collective movement of mobile robots are studied. This framework is implemented in a distributed manner among the robots and allows scalability with increasing number of robots. It is expandable with new functionalities through the inclusion of new modules. Splitting functionality is created by including a new module, while joining does not need new structures. A total of 130 systematic experiments, grouped in six different sets, were undertaken to test the splitting and joining functions of the framework, yielding results in which robots behaved as expected. Four of the sets correspond to experiments in simulation using up to 40 robots. The remaining sets use eight real robots.

  2. Performance of electro-plated and joined components for divertor application

    Energy Technology Data Exchange (ETDEWEB)

    Krauss, Wolfgang, E-mail: wolfgang.krauss@kit.edu; Lorenz, Julia; Konys, Jürgen

    2013-10-15

    Highlights: • Active interlayers of Ni and Pd were electroplated on W to assist joining. • Demonstrator types of W-steel and W–W joints were successfully fabricated. • Diffusion processes increase operation temperature above brazing temperature. • Ni electro-plating is less sensitive to variation of deposition parameters than Pd. • Shear tests showed values in resistance comparable to those of commercial fillers. -- Abstract: A general challenge in divertor development, independently of design type and cooling medium water or helium, is the reliable and adapted joining of components. Depending on the design variants, the characteristics of the joints will be focused on functional or structural behavior to guarantee e.g. good thermal conductivity and sufficient mechanical strength. All variants will have in common that tungsten is the plasma facing material. Thus, material combinations to be joined will range from Cu base over steel to tungsten. Especially tungsten shows lacks in adapted joining due to its metallurgical behavior ranging from immiscibility over bad wetting up to brittle intermetallic phase formation. Joining assisted by electro-chemical deposition of functional and filler layers showed that encouraging progress was achieved in wetting applying nickel interlayers. Nickel proved to be a good reference material but alternative elements (e.g. Pd, Fe) may be more attractive in fusion to manufacture suitable joints. Replacing of Ni as activator element by Pd for W/W or W/steel joints was achieved and joining with Cu-filler was successfully performed. Manufactured joints were characterized applying metallurgical testing and SEM/EDX analyses demonstrating the applicability of Pd activator. First shear tests showed that the joints exhibit mechanical stability sufficient for technical application.

  3. The CMT-process and its possible applications, especially joining of steel with aluminium; Der CMT - Prozess und seine Moeglichkeiten, im speziellen das Fuegen von Stahl mit Aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Bruckner, J.; Himmelbauer, K.; Hackl, H. [Fronius International GmbH, Wels (Austria)

    2004-07-01

    Knowing how to weld dissimilar metals is becoming more and more important. One reason is that it's often impossible for one material to provide the optimum chemical, physical, and mechanical characteristics needed for an application. For this reason, as well as cost efficiency, technology specialists are experimenting with different joining processes to weld bimetal joints optimally. A reliable method of joining the two most commonly used metals, steel and aluminum, would make it possible to make these joints in several applications. On one hand, aluminum is becoming increasingly more important in the automotive industry because of its good processing and performance characteristics and because it's lightweight, which results in lower fuel consumption. Given today's heightened need to decrease energy consumption, aluminum is a major player in modern-day mechanical engineering. On the other hand, steel continues to dominate many fields of engineering, a fact underlined by the development of high-strength and superhigh-strength steels. When different metals are joined, each metal's features should be considered. It's important to pay attention to the chemical and physical properties-such as the corrosion behavior and thermal expansion coefficient-and to atomic properties, such as the lattice constant and type of crystalline lattice. Processes typically used to join dissimilar metals are bonding, riveting, or clinching, which essentially have no influence on the metals' atomic properties. Another method, thermal joining, can shorten joining time, produce tight seams, and provide high strength. (orig.)

  4. [Joining WHO of Republic of Korea and the projects in the 1950s].

    Science.gov (United States)

    Lee, Sun Ho

    2014-04-01

    The Republic of Korea(ROK) and the World Health Organization(WHO) have done many projects successfully from 1949, in which the government of First Republic joined the WHO. However the relation between the ROK and the WHO have not been studied very much so far. The main purpose of this research, which could be done by the support of WHO, is connected with three questions. First research point would be "how could the ROK joined WHO in 1949 and what's the meaning of it? And the what's the difference in the process for the WHO between the ROK of 1949 and the DPRK(Democratic People's Republic of Korea) of 1973?" The first president of the ROK, Rhee Syngman, who had received his Ph. D.(about international politics) from Princeton University in 1910, was strongly interested in joining international institutes like UN, WHO. The ROK that could join WHO on 17 August 1949, with the approval of Assembly on 25 May 1949, was one of the founder members of the Western Pacific Region. By joining WHO, the ROK could get chance to increase the level of public health and its administration in 1950's. But the DPRK manage to became a member of WHO on 19 May 1973 and joined the South-East Asia Region. The joining of DPRK was influenced by the easing of the cold war after the Nixon Doctrine and the joining of the China(People's Republic of China). Second research point would be "What kind of roll did the WHO take in the First Republic?" Yet the public health administration of the First Republic that had been made in the period of US army military government was been strongly influenced by USA, the roll of WHO was also important in the 1950's. Last research point would be "What kind of the projects did the ROK and the WHO take part in during the period of he First Republic? How could evaluate the results?" The ROK and the WHO handled the projects including health services, communicable disease prevention and control, control of noncommunicable diseases, and protection of health. Specially

  5. Molecular dynamics simulation of joining process of Ag-Au nanowires and mechanical properties of the hybrid nanojoint

    Directory of Open Access Journals (Sweden)

    Su Ding

    2015-05-01

    Full Text Available The nanojoining process of Ag-Au hybrid nanowires at 800K was comprehensively studied by virtue of molecular dynamics (MD simulation. Three kinds of configurations including end-to-end, T-like and X-like were built in the simulation aiming to understand the nanojoining mechanism. The detailed dynamic evolution of atoms, crystal structure transformation and defects development during the nanojoining processes were performed. The results indicate that there are two stages in the nanojoining process of Ag-Au nanowires which are atom diffusion and new bonds formation. Temperature is a key parameter affecting both stages ascribed to the energy supply and the optimum temperature for Ag-Au nanojoint with diameter of 4.08 nm has been discussed. The mechanical properties of the nanojoint were examined with simulation of tensile test on the end-to-end joint. It was revealed that the nanojoint was strong enough to resist fracture at the joining area.

  6. Kinematics analysis and optimization of the fast shearing-extrusion joining mechanism for solid-state metal

    Science.gov (United States)

    Zhang, Shuangjie; Yao, Yunfeng; Li, Lingchong; Wang, Lijuan; Li, Junxia; Li, Qiang

    2015-11-01

    Dynamical Joining of the solid-state metal is the key technology to realize endless hot rolling. The heating and laser welding method both require long joining time. Based on super deformation method, a 7-bar and 2-slider mechanism was developed in Japan, and the joining time is less than 0.5 s, however the length of each bar are not reported and this mechanism is complex. A relatively simple 6-bar and 1-slider mechanism is put forward, which can realize the shearing and extrusion motion of the top and bottom blades with a speed approximately equal to the speed of the metal plates. In order to study the kinematics property of the double blades, based on complex vector method, the multi-rigid-body model is built, and the displacement and speed functions of the double blades, the joining time and joining thickness are deduced, the kinematics analysis shows that the initial parameters can't satisfy the joining process. Hence, optimization of this mechanism is employed using genetic algorithm(GA) and the optimization parameters of this mechanism are obtained, the kinematics analysis show that the joining time is less than 0.1 s, the joining thickness is more than 80% of the thickness of the solid-state metal, and the horizontal speeds of the blades are improved. A new mechanism is provided for the joining of the solid-state metal and a foundation is laid for the design of the device.

  7. Kinematics Analysis and Optimization of the Fast Shearing-extrusion Joining Mechanism for Solid-state Metal

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shuangjie; YAO Yunfeng; LI Lingchong; WANG Lijuan; LI Junxia; LI Qiang

    2015-01-01

    Dynamical Joining of the solid-state metal is the key technology to realize endless hot rolling. The heating and laser welding method both require long joining time. Based on super deformation method, a 7-bar and 2-slider mechanism was developed in Japan, and the joining time is less than 0.5 s, however the length of each bar are not reported and this mechanism is complex. A relatively simple 6-bar and 1-slider mechanism is put forward, which can realize the shearing and extrusion motion of the top and bottom blades with a speed approximately equal to the speed of the metal plates. In order to study the kinematics property of the double blades, based on complex vector method, the multi-rigid-body model is built, and the displacement and speed functions of the double blades, the joining time and joining thickness are deduced, the kinematics analysis shows that the initial parameters can’t satisfy the joining process. Hence, optimization of this mechanism is employed using genetic algorithm(GA) and the optimization parameters of this mechanism are obtained, the kinematics analysis show that the joining time is less than 0.1 s, the joining thickness is more than 80% of the thickness of the solid-state metal, and the horizontal speeds of the blades are improved. A new mechanism is provided for the joining of the solid-state metal and a foundation is laid for the design of the device.

  8. Esquel Group and LEGO Group Joined Hands to Establish "Mindstorms Robotics Workshop"

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ With a mission"To encourage the Spirit of Learning"and to enhance learning opportunities for children in need,Esquel Group joined hands with Lego Group,and Semia Limited and established"Mindstorms Robotics Workshop"and donated RMB 200,000worth of educational robotic equipments to the Xinjiang Science and Technology Museum.

  9. Pauling bond strength, bond length and electron density distribution

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, Gerald V.; Ross, Nancy L.; Cox, David F.; Rosso, Kevin M.; Iversen, Bo B.; Spackman, M. A.

    2014-01-18

    A power law regression equation, = 1.46(<ρ(rc)>/r)-0.19, connecting the average experimental bond lengths, , with the average accumulation of the electron density at the bond critical point, <ρ(rc)>, between bonded metal M and oxygen atoms, determined at ambient conditions for oxide crystals, where r is the row number of the M atom, is similar to the regression equation R(M-O) = 1.39(ρ(rc)/r)-0.21 determined for three perovskite crystals for pressures as high as 80 GPa. The two equations are also comparable with those, = 1.43(/r)-0.21, determined for a large number of oxide crystals at ambient conditions and = 1.39(/r)-0.22, determined for geometry optimized hydroxyacid molecules, that connect the bond lengths to the average Pauling electrostatic bond strength, , for the M-O bonded interactions. On the basis of the correspondence between the two sets of equations connecting ρ(rc) and the Pauling bond strength s with bond length, it appears that Pauling’s simple definition of bond strength closely mimics the accumulation of the electron density between bonded pairs of atoms. The similarity of the expressions for the crystals and molecules is compelling evidence that the M-O bonded interactions for the crystals and molecules 2 containing the same bonded interactions are comparable. Similar expressions, connecting bond lengths and bond strength, have also been found to hold for fluoride, nitride and sulfide molecules and crystals. The Brown-Shannon bond valence, σ, power law expression σ = [R1/(R(M-O)]N that has found wide use in crystal chemistry, is shown to be connected to a more universal expression determined for oxides and the perovskites, <ρ(rc)> = r[(1.41)/]4.76, demonstrating that the bond valence for a bonded interaction is likewise closely connected to the accumulation of the electron density between the bonded atoms. Unlike the Brown-Shannon expression, it is universal in that it holds for the M

  10. Processing of pro-opiomelanocortin-derived amidated joining peptide and glycine-extended precursor in monkey pituitary

    DEFF Research Database (Denmark)

    Fenger, M

    1991-01-01

    The molecular forms of proopiomelanocortin (POMC) derived amidated and C-terminal glycine-extended joining peptide from monkey (Macaca mulatta) pituitary were determined. The predominant forms of joining peptide found were the low molecular peptides POMC(76-105) and POMC(76-106), respectively....... Significant amounts of N-terminally truncated POMC(78-105) and POMC(78-106) were also detected in the posterior-intermediate lobe. No N-terminal extended forms were detected. The relative amount of amidated joining peptide to total joining peptide was 6-35%. It is concluded that not only is the primary...

  11. PRESS RELEASE-Foseco and ProService Join Forces for Thermal Analysis Systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ Foseco and ProService have joined forces to drive the development of thermal analysis as the leading metallurgical control tool for iron foundries. As part of the agreement, Foseco has funded the development of a web-based version of ITACA and ProService have appointed Foseco as exclusive distributors for its ITACA Thermal Analysis systems.

  12. Natural join construction of graded posets versus ordinal sum and discrete hyper boxes

    CERN Document Server

    Kwasniewski, A K

    2009-01-01

    One introduces here the natural join $P \\os Q$ of graded posets $$ and $$ with correspondingly maximal and minimal sets being identical as expressed by ordinal sum $P\\oplus Q$ apart from other definition and due to that one arrives at a simple proof of the $M{\\"{o}}bius $ function formula for cobweb posets. We also quote the other authors explicit formulas for the zeta matrix and its inverse for any graded posets with the finite set of minimal elements from earlier works of the author. These formulas are based on the formulas for cobweb posets and their $Hasse$ diagrams or graphs named $KoDAGs$ which are interpreted as chains of binary complete or universal relations joined by the natural join operation. Natural join of two independent sets is therefore the ordinal sum of this trivially ordered posets represented also by directed biclique named dibiclique and correspondingly by their $Hasse $ diagrams or graphs named $KoDAGs$. Such cobweb posets and equivalently their Hasse diagrams or graphs named $KoDAGs$ a...

  13. Performance Comparison of the Optimized Inverted Joined Wing Airplane Concept and Classical Configuration Airplanes

    Directory of Open Access Journals (Sweden)

    Sieradzki Adam

    2016-09-01

    Full Text Available The joined wing concept is an unconventional airplane configuration, known since the mid-twenties of the last century. It has several possible advantages, like reduction of the induced drag and weight due to the closed wing concept. The inverted joined wing variant is its rarely considered version, with the front wing being situated above the aft wing. The following paper presents a performance prediction of the recently optimized configuration of this airplane. Flight characteristics obtained numerically were compared with the performance of two classical configuration airplanes of similar category. Their computational fluid dynamics (CFD models were created basing on available documentation, photographs and some inverse engineering methods. The analysis included simulations performed for a scale of 3-meter wingspan inverted joined wing demonstrator and also for real-scale manned airplanes. Therefore, the results of CFD calculations allowed us to assess the competitiveness of the presented concept, as compared to the most technologically advanced airplanes designed and manufactured to date. At the end of the paper, the areas where the inverted joined wing is better than conventional airplane were predicted and new research possibilities were described.

  14. Why Universities Join Cross-Sector Social Partnerships: Theory and Evidence

    Science.gov (United States)

    Siegel, David J.

    2010-01-01

    Cross-sector partnerships are an increasingly popular mode of organizing to address intractable social problems, yet theory and research have virtually ignored university involvement in such activity. This article attempts to ascertain the reasons universities join networks of other social actors to support a common cause. Theories on the…

  15. Magnetomotive forming for precision sizing and joining of large-diameter tubes

    Science.gov (United States)

    Bennight, J. D.; Schwinghamer, R. J.

    1969-01-01

    Portable electromagnetic coil enables high precision expansion or constriction and joining of large diameter metal tubes. A nonconducting mandrel or forming die is used on the side of the tubes wall opposite the coil. The coil is insulated from the tube by a thin plastic sleeve.

  16. CCI and CI Join Hands:A Better Supply Chain with More Innovations on Cotton Fabrics

    Institute of Scientific and Technical Information of China (English)

    Tom; Xue

    2010-01-01

    Cotton Council International("CCI")and Cotton Incorporated("CI") joined forces again,from October 19-22,2010 at Intertextile Shanghai,to promote natural fiber-U.S.cotton.As global textile strategic partners,both organizations were bringing together alliances through the cotton

  17. Status of Joining Thin Sheet and Thin Wall Tubes of 14YWT

    Energy Technology Data Exchange (ETDEWEB)

    Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Unocic, Kinga A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tang, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-18

    Beginning this fiscal year, the FCRD research project initiated an investigation on joining thin sections of the advanced ODS 14YWT ferritic alloy. Friction stir welding (FSW) was investigated as a method to join thin plate and tubing of 14YWT since it is a solid state joining method that has been shown in past studies to be a promising method for joining plates of ODS alloys, such as 14YWT. However, this study will attempt to be the first to demonstrate if FSW can successfully join thin plates and thin wall tubing of 14YWT. In the first FSW attempt, a 1.06 cm thick plate of 14YWT (SM13 heat) was successfully rolled at 1000ºC to the target thickness of 0.1 cm with no edge cracking. This achievement is a highlight since previous attempts to roll 14YWT plates have resulted in extensive cracking. For the FSW run, a pin tool being developed by the ORNL FSW Process Development effort was used. The first FSW run successfully produced a bead-on-plate weld in the 0.1 cm thick plate. The quality of the weld zone appears very good with no evidence of large defects such as cavities. The microstructural characterization study of the bead-on-plate weld zone has been initiated to compare the results of the microstructure analysis with those obtained in the reference microstructural analysis of the 14YWT (SM13 heat) that showed ultra-fine grain size of 0.43 μm and a high number density of ~2-5 nm sizes oxygen-enriched nanoclusters.

  18. Joining the club: Conforming to and resisting biology in practice

    Science.gov (United States)

    Buxton, Cory Alexander

    2000-10-01

    This study explores how science and scientists were produced and reproduced within the setting of a university biology department. It builds upon recent work in anthropology of education and feminist science studies. My purpose was to look at both the contextual and constitutive values of science as they were negotiated and played out in the training of scientists in a setting where: (1) women were well represented in leadership positions; and (2) "mainstream" science was being both taught and practiced. Findings included the organization of a status hierarchy within the department, the meanings of science and scientists that students constructed within the social spaces they occupied, examples of individual resistance to certain norms of biology practice, and examples of institutional opposition to that resistance. There was some evidence that the unusually high representation of women in positions of leadership in the biology department did result in changes in both the contextual and constitutive values of how science was conceptualized, practiced and taught in this setting. Contextually, social spaces controlled by women were likely to emphasize: (1) teamwork bringing together participants with varied backgrounds and perspectives; (2) flexible and collaborative use of physical space; and (3) willingness to do work for which they went unacknowledged or to share rewards equally even when the work distribution was not equitable. Constitutively, these social spaces were prone to: (1) interdisciplinary synthesis and comprehensive approaches; (2) the study of topics that reconsidered beliefs about gender roles in plant and animal reproduction; (3) work that would be slower and take longer to produce (and publish) but might make a large contribution (be a high quality product) eventually; and (4) an awareness by women that their practices were different in some ways than the practices of their male colleagues.

  19. Rethinking Research in Early Care and Education: Joining Sally's Quest

    Science.gov (United States)

    New, Rebecca S.

    2008-01-01

    The article considers three domains of Sally Lubeck's scholarship as illustrations of her orientation to research on early care and education: her critique of positivism in general and the field of developmental psychology (and the sub-discipline of child development) specifically as the primary source of a "knowledge base" for the field of early…

  20. Talking REDD+: Beyond forestry - joining up and moving forward

    Energy Technology Data Exchange (ETDEWEB)

    Nhantumbo, Isilda; Rolington, Leianne

    2011-12-15

    On Sunday 27 November 2011, the eve of the 17th conference of the parties to the UNFCCC (COP17), the International Institute for Environment and Development, together with its partners, hosted a South-South learning event, 'REDD+, poverty reduction and sustainable development: are there cost-effective and pro-poor options?' This was a platform to share information about the practices that already work, to discuss how REDD+ can build on and scale up cost-effective options that deal with the fundamental problem of climate change. Deforestation and degradation of forests requires concerted interventions across national and regional borders. Learning from each other's experience in dealing with the underlying problems and understanding how to adapt them to a different local context is critical – and will help to both ensure its success and to lower transaction costs. This briefing gives an overview of the key REDD+ issues, in particular: integrating mitigation and adaptation actions; addressing tenure; learning from participatory forest management and payment for ecosystems services; taking the right approach to gender; developing safeguards to minimize negative impacts of REDD+; and strengthening South-South collaboration to reduce the transaction costs of REDD+.

  1. OF ALIENATION, ASSOCIATION, AND ADVENTURE: WHY GERMAN FIGHTERS JOIN ISIL

    Directory of Open Access Journals (Sweden)

    Dorle Hellmuth

    2016-03-01

    Full Text Available This article provides an analysis of German foreign fighters who have left for Syria and Iraq since early 2012 and make up the second largest contingent among Western foreign fighters. It draws on statistical information about German foreign fighters, but also uses case studies in an attempt to shed more detailed light on their motivations and why they became radicalized. Drawing on recently released government data, trial documents, and media reports, the article seeks to contribute to new research on the prevailing mechanisms of Jihadi radicalization. To facilitate this kind of comprehensive analysis, McCauley and Moskalenko’s Friction framework is applied to fourteen prominent German fighters, including Denis Cuspert (who served as medium-level ISIL propaganda official, Philip Bergner and Robert Baum (responsible for ISIL suicide attacks in Iraq and Syria, Kreshnik B. and Harun Pashtoon (among the first returning fighters convicted of ISIL membership and other terrorist activities. The article concludes with a discussion of countermeasures used to prevent foreign fighters from leaving Germany, deradicalize those who have started to embrace violent ideas and/or actions, and deal with returning foreign fighters.

  2. Mexico joins the venture: Joint Implementation and Greenhouse Gas Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Imaz, M.; Gay, C.; Friedmann, R.; Goldberg, B.

    1998-11-01

    Joint Implementation (JI) and its pilot phase of Activities Implemented Jointly (AIJ) are envisioned as an economic way of reducing global emissions of greenhouse gases. This paper draws upon the Mexican experience with AIJ to identify Mexican concerns with AIJ/JI and proposed solutions to these. Three approved Mexican AIJ projects (Ilumex, Scolel Te, and Salicornia) are described in detail. The Ilurnex project promotes the use of compact fluorescent lamps in Mexican homes of the States of Jalisco and Nuevo Leon, to reduce electric demand. Scolel Te is a sustainable forest management project in Chiapas. Salicornia examines the potential for carbon sequestration with a Halophyte-based crop irrigated with saline waters in Sonora. These three projects are reviewed to clarify the issues and concerns that Mexico has with AIJ and JI and propose measures to deal with them. These initial Mexican AIJ projects show that there is a need for creation of standard project evaluation procedures, and criteria and institutions to oversee project design, selection, and implementation. Further JI development will be facilitated by national and international clarification of key issues such as additionality criteria, carbon-credit sharing, and valuation of non-GHG environmental and/or social benefits and impacts for AIJ projects. Mexico is concerned that JI funding could negatively impact official development assistance or that OECD countries will use JI to avoid taking significant GHG mitigation actions in their own countries. The lack of carbon credit trading in the AIJ stage must be removed to provide useful experience on how to share carbon credits. National or international guidelines are needed to ensure that a portion of the carbon credits is allocated to Mexico.

  3. CERN and Caltech join forces to smash Internet speed record

    CERN Multimedia

    2003-01-01

    CERN and California Institute of Technology (Caltech) will receive an award for transferring over a Terabyte of data across 7,000 km of network at 5.44 gigabits per second (Gbps), smashing the old record of 2.38 Gbps achieved in February between CERN in Geneva and Sunnyvale in California by a Caltech, CERN, Los Alamos National Laboratory and SLAC team (1/2 page).

  4. Weldability and joining techniques for advanced fossil energy system alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, C.D.; Qiao, C.Y.P.; Liu, W.; Yang, D.; Zhou, G.; Morrison, M. [Univ. of Tennessee, Knoxville, TN (United States)

    1998-05-01

    The efforts represent the concerns for the basic understanding of the weldability and fabricability of the advanced high temperature alloys so necessary to affect increases in the efficiency of the next generation Fossil Energy Power Plants. The effort was divided into three tasks with the first effort dealing with the welding and fabrication behavior of 310HCbN (HR3C), the second task details the studies aimed at understanding the weldability of a newly developed 310TaN high temperature stainless (a modification of 310 stainless) and Task 3 addressed the cladding of austenitic tubing with Iron-Aluminide using the GTAW process. Task 1 consisted of microstructural studies on 310HCbN and the development of a Tube Weldability test which has applications to production welding techniques as well as laboratory weldability assessments. In addition, the evaluation of ex-service 310HCbN which showed fireside erosion and cracking at the attachment weld locations was conducted. Task 2 addressed the behavior of the newly developed 310 TaN modification of standard 310 stainless steel and showed that the weldability was excellent and that the sensitization potential was minimal for normal welding and fabrication conditions. The microstructural evolution during elevated temperature testing was characterized and the second phase particles evolved upon aging were identified. Task 3 details the investigation undertaken to clad 310HCbN tubing with Iron Aluminide and developed welding conditions necessary to provide a crack free cladding. The work showed that both a preheat and a post-heat was necessary for crack free deposits and the effect of a third element on the cracking potential was defined together with the effect of the aluminum level for optimum weldability.

  5. Joining of Ukraine to the European scientific and metric systems

    Directory of Open Access Journals (Sweden)

    O.M. Sazonets

    2015-09-01

    Full Text Available At the present stage of development it is necessary to form the knowledge which structures knowledge as the object of management. In conditions of technological globalism there are structural changes in the information environment of countries. Scientific metrics is sufficiently developed in other countries, especially in the EU. The article contains the description of the first index calculation system of scientific references called Science Citation Index (SCI. The main advantage of this project was searching for information not only by the author and thematic categories, but also by the list of cited literature. The authors define the scientific and metric base in the following way: scientific and metric database (SMBD is the bibliographic and abstract database with the tools for tracking citations of articles published in scientific journals. The most prominent European scientific and metric bases are examined. The authors show that the bases have the performance assessment tools which track down the impact of scientific papers and publications of individual scientists and research institutions. The state of crisis in scientific and technological activities in Ukraine as well as the economy as a whole, needs immediate organization of national scientific and metric system.

  6. Chemotaxis : signalling modules join hands at front and tail

    NARCIS (Netherlands)

    Haastert, Peter J.M. van; Devreotes, Peter N.

    2004-01-01

    Chemotaxis is the result of a refined interplay among various intracellular molecules that process spatial and temporal information. Here we present a modular scheme of the complex interactions between the front and the back of cells that allows them to navigate. First, at the front of the cell, act

  7. Joining Theory and Best Practice To Drive Classroom Instruction.

    Science.gov (United States)

    Fuhler, Carol J.

    2003-01-01

    Describes three theories supporting reading instruction--schema theory, the constructivist approach, and literary response theory--and offers best classroom practices that support these theories. Provides a sample lesson illustrating possible cross-curricular interactions, also considered a best practice. (EV)

  8. Sinopec and CNOOC Join Hands for Oil Import

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Sinopec and CNOOC, two of China's big-three oil companies, have set up a joint venture to import crude oil.The joint venture makes CNOOC the fifth largest crude oil importer in China. Following the move, CNOOC is also likely to gain government approval to build a large refinery and market oil products this year, company executives said.

  9. Software Junctus: Joining Sign Language and Alphabetical Writing

    Science.gov (United States)

    Valentini, Carla Beatris; Bisol, Cláudia A.; Dalla Santa, Cristiane

    The authors’ aim is to describe the workshops developed to test the use of an authorship program that allows the simultaneous use of sign language and alphabetical writing. The workshops were prepared and conducted by a Computer Science undergraduate, with the support of the Program of Students’ Integration and Mediation (Programa de Integração e Mediação do Acadêmico - PIMA) at the University of Caxias do Sul. Two sign language interpreters, two deaf students and one hearing student, who also teach at a special school for the deaf, participated in the workshops. The main characteristics of the software and the development of the workshops are presented with examples of educational projects created during their development. Possible improvements are also outlined.

  10. Elections for staff representatives – Join, commit and vote!

    CERN Multimedia

    Staff Association

    2015-01-01

    The Staff Council is a statutory body representing collectively in the area of employment conditions all CERN staff members (MPE and MPA), as well as the pensioners, former Cernois. The Staff Council is the supreme representative body of the CERN staff and pensioners, which defines the main lines of the policy of the Staff Association. The Staff Council is composed of staff representatives (45 seats to represent staff members, and 5 for representing fellows and associate members), as well as delegates for pensioners (seven positions), designated by GAC-EPA. Every two years, the Council is renewed through elections. Concerning the 45 delegates representing staff members, all departments have a least two seats allocated, one in career paths AA to D and one in career paths E to H. This guarantees a fair distribution of seats among the various organizational units and career paths. The table below, shows the exact number of delegates per department and career paths. Staff members or fellows who want to participa...

  11. Localisation - When Language, Culture and Technology Join Forces

    Directory of Open Access Journals (Sweden)

    Jody Byrne

    2012-08-01

    Full Text Available When you switch on your computer and type up a letter, what language do you see? What about when you visit a website or play a computer game? Does your mobile phone speak your language? Chances are that each of these technological marvels of the modern age communicates with you in your own language. For many of us, this is so commonplace and seamless that we hardly give it a moment's thought but behind the scenes there is a whole industry dedicated to making sure that technology bridges the gap between language and culture without you even noticing.

  12. Joining a healing community for cancer: who and why?

    Science.gov (United States)

    Sutherland, C E; Goldstein, M S

    1992-08-01

    This paper provides a description and evaluation of selected aspects of The Wellness California. Based upon participant observation, TWC's philosophy and program are described. The ways in which charismatic leadership is used to create a sense of 'healing charisma' is specified. Interviews were conducted at 3 points over a 10 month period with 65 individuals who initiated contact with TWC. Thirty-seven eventually became participants at TWC, while the 28 who did not were used as a comparison group. Participants were healthier, more oriented toward self-care and less satisfied with their existing social support networks. The findings indicate the role, and limitations, of healing communities for people with chronic physical illness.

  13. Chinese and Foreign Oil Giants Join Hands for Petrol Stations

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ The negotiation on the 500 joint venture petrol stations between Sinopec and Royal Dutch/ Shell Group is now under the final stage. Once the negotiation is wound up, the first number of the joint venture petrol stations will be put into operation in Jiangsu Province within three months after the signature of the agreement. The remaining ones will be constructed and put into operation in three years.

  14. Thin layer joining by gas adsorption

    Science.gov (United States)

    Taga, Yasunori; Fukumura, Toshio

    2014-10-01

    Attempt has been made to join borosilicate glass and cycloolefin (COP) polymer film by using gas adsorption method. After corona plasma treat, COP was exposed to (3-glycidoxypropyl) trimethoxysilane (GPS) and glass to (3-aminopropyl) triethoxysilane (APS) both in air atmosphere, resulting in co-adsorption of water vapor in the atmosphere and organosilane gases. Surface characterization of plasma treated and gas adsorbed surfaces was carried out by X-ray photoelectron spectroscopy (XPS) using Mg Kα X-ray source. Joining was carried out by a roll laminator after contact of both surfaces at room temperature, followed by annealing at 130 °C for 10 min. Adhesion strength was evaluated by 180 degree peel test based on ASTM D-903 and durability was examined under the conditions of 60 °C and 95% RH. It was found that after plasma treatment, complex functional groups such as Csbnd H, Csbnd O, Cdbnd O, Osbnd Cdbnd O and CO3 were found on COP and Osbnd H on glass. Thickness of GPS gas adsorption layer on COP was evaluated by the XPS to be at least 1.1 nm by taking inelastic mean free path of Si2p photoelectron into consideration. Joining force was found to be more than 5 N/25 mm corresponding to almost equal to COP bulk tensile strength. In addition, durability of this adhesion strength remained unchanged over 2000 h even after exposure to the durability test conditions of 60 °C and 95% RH. The results can be explained in terms of formation of Hsbnd H hydrogen bonding and Sisbnd O covalent bonding via silanols will be made at the interface as a result of lamination and annealing processes. In conclusion, ultrathin joining method by gas adsorption was established by the formation of hydrogen and covalent bonds at the interface by low temperature reaction process.

  15. Biology coming full circle: joining the whole and the parts.

    Science.gov (United States)

    Wikswo, John P; Porter, Andrew P

    2015-01-01

    The new cover of Experimental Biology and Medicine features the hermeneutic circle of biology, a concept we have adapted from the hermeneutic principle that one understands the whole only in terms of each part and the parts only in terms of the whole. Our hermeneutic circle summarizes the course of experimental biology through 2500 years of the achievements of reductionist research (understanding the parts), which culminates in our ability to rapidly sequence the genome. Rather than returning along the same path in a constructionist approach that simply builds upon this knowledge, but in reverse, an alternative is to close the circle with synthetic constructions that seek to integrate the full complexity of biological and physiological systems (understanding the whole), of which organs-on-chips are one example. This closing of the circle cannot be a comprehensively accurate representation of biology, but it can be a synthetic one that effectively defines particular biological subsystems. The illustration of the hermeneutic circle of biology is also intended to suggest both the multiple cycles that may be required to reach such a synthesis and the expansion of the circle in an outward spiral as knowledge increases. Our commentary explains the symbolism of the new cover in a philosophical and scientific discussion.

  16. Joining primeness and disjointness from infinitely divisible systems

    CERN Document Server

    Lemanczyk, Mariusz; Roy, Emmanuel

    2009-01-01

    We show that ergodic dynamical systems generated by infinitely divisible stationary processes are disjoint in the sense of Furstenberg with distally simple systems and systems whose maximal spectral type is singular with respect to the convolution of any two continuous measures.

  17. Joining and Integration of Silicon Nitride Ceramics for Aerospace and Energy Systems

    Science.gov (United States)

    Singh, M.; Asthana, R.

    2009-01-01

    Light-weight, creep-resistant silicon nitride ceramics possess excellent high-temperature strength and are projected to significantly raise engine efficiency and performance when used as turbine components in the next-generation turbo-shaft engines without the extensive cooling that is needed for metallic parts. One key aspect of Si3N4 utilization in such applications is its joining response to diverse materials. In an ongoing research program, the joining and integration of Si3N4 ceramics with metallic, ceramic, and composite materials using braze interlayers with the liquidus temperature in the range 750-1240C is being explored. In this paper, the self-joining behavior of Kyocera Si3N4 and St. Gobain Si3N4 using a ductile Cu-based active braze (Cu-ABA) containing Ti will be presented. Joint microstructure, composition, hardness, and strength as revealed by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Knoop microhardness test, and offset compression shear test will be presented. Additionally, microstructure, composition, and joint strength of Si3N4/Inconel 625 joints made using Cu-ABA, will be presented. The results will be discussed with reference to the role of chemical reactions, wetting behavior, and residual stresses in joints.

  18. 27 CFR 19.245 - Bonds and penal sums of bonds.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bonds and penal sums of... Bonds and penal sums of bonds. The bonds, and the penal sums thereof, required by this subpart, are as follows: Penal Sum Type of bond Basis Minimum Maximum (a) Operations bond: (1) One plant bond—...

  19. Exploring the Fitness Centre Industry in Malaysia; What Factors Influence Joining and Retention and Prevents People from Joining

    OpenAIRE

    Smith, Helen B

    2008-01-01

    Malaysia’s fitness centre industry has seen rapid growth over the last 6 years with the opening of more than 25 international chain outlets of which the majority is owned by California Fitness, Celebrity Fitness, Fitness First and True Fitness. An increasing population and year on year GDP growth, together with the support of the Malaysian government, contribute to further the growth of the industry. The purpose of the study is to explore, investigate and reveal information about the growth a...

  20. Ring-constrained Join

    DEFF Research Database (Denmark)

    Yiu, Man Lung; Karras, Panagiotis; Mamoulis, Nikos

    2008-01-01

    We introduce a novel spatial join operator, the ring-constrained join (RCJ). Given two sets P and Q of spatial points, the result of RCJ consists of pairs (p, q) (where p ε P, q ε Q) satisfying an intuitive geometric constraint: the smallest circle enclosing p and q contains no other points in P, Q...... R-tree based algorithms for computing RCJ, by exploiting the characteristics of the geometric constraint. We evaluate experimentally the efficiency of our methods on synthetic and real spatial datasets. The results show that our proposed algorithms scale well with the data size and have robust...

  1. Heat Bonding of Irradiated Ethylene Vinyl Acetate

    Science.gov (United States)

    Slack, D. H.

    1986-01-01

    Reliable method now available for joining parts of this difficult-tobond material. Heating fixture encircles ethylene vinyl acetate multiplesocket part, providing heat to it and to tubes inserted in it. Fixtures specially designed to match parts to be bonded. Tube-and-socket bonds made with this technique subjected to tensile tests. Bond strengths of 50 percent that of base material obtained consistently.

  2. Equitable Strong Edge Coloring of the Joins of Paths and Cycles

    Institute of Scientific and Technical Information of China (English)

    Tao WANG; Ming Ju LIU; De Ming LI

    2012-01-01

    For a proper edge coloring c of a graph G,if the sets of colors of adjacent vertices are distinct,the edge coloring c is called an adjacent strong edge coloring of G.Let ci be the number of edges colored by i.If |ci - cj| ≤ 1 for any two colors i and j,then c is an equitable edge coloring of G.The coloring c is an equitable adjacent strong edge coloring of G if it is both adjacent strong edge coloring and equitable edge coloring.The least number of colors of such a coloring c is called the equitable adjacent strong chromatic index of G.In this paper,we determine the equitable adjacent strong chromatic index of the joins of paths and cycles.Precisely,we show that the equitable adjacent strong chromatic index of the joins of paths and cycles is equal to the maximum degree plus one or two.

  3. The Developmental Dynamics of Joining a Gang in Adolescence: Patterns and Predictors of Gang Membership.

    Science.gov (United States)

    Gilman, Amanda B; Hill, Karl G; Hawkins, J David; Howell, James C; Kosterman, Rick

    2014-06-01

    Researchers have examined the predictors of adolescent gang membership, finding significant factors in the neighborhood, family, school, peers, and individual domains. However, little is known about whether risk and protective factors differ in predictive salience at different developmental periods. The present study examines predictors of joining a gang, tests whether these factors have different effects at different ages, and whether they differ by gender using the Seattle Social Development Project (SSDP) sample (n=808). By age 19, 173 participants had joined a gang. Using survival analysis, results showed that unique predictors of gang membership onset included living with a gang member, antisocial neighborhood, and antisocial peer influences in the previous year. No time or gender interactions with predictors were statistically significant.

  4. Modeling and Testing Miniature Torsion Specimens for SiC Joining Development Studies for Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H.; Nguyen, Ba Nghiep; Kurtz, Richard J.; Roosendaal, Timothy J.; Borlaug, Brennan A.; Ferraris, Monica; Ventrella, Andrea; Katoh, Yutai

    2015-08-19

    The international fusion community has designed a miniature torsion specimen for neutron irradiation studies of joined SiC and SiC/SiC composite materials. Miniature torsion joints based on this specimen design were fabricated using displacement reactions between Si and TiC to produce Ti3SiC2 + SiC joints with CVD-SiC and tested in torsion-shear prior to and after neutron irradiation. However, many of these miniature torsion specimens fail out-of-plane within the CVD-SiC specimen body, which makes it problematic to assign a shear strength value to the joints and makes it difficult to compare unirradiated and irradiated joint strengths to determine the effects of the irradiation. Finite element elastic damage and elastic-plastic damage models of miniature torsion joints are developed that indicate shear fracture is likely to occur within the body of the joined sample and cause out-of-plane failures for miniature torsion specimens when a certain modulus and strength ratio between the joint material and the joined material exists. The model results are compared and discussed with regard to unirradiated and irradiated joint test data for a variety of joint materials. The unirradiated data includes Ti3SiC2 + SiC/CVD-SiC joints with tailored joint moduli, and includes steel/epoxy and CVD-SiC/epoxy joints. The implications for joint data based on this sample design are discussed.

  5. Nested Fork-Join Queuing Networks and Their Application to Mobility Airfield Operations Analysis.

    Science.gov (United States)

    1997-03-01

    Method. The accuracy of this approximation is similar to that of its single-class counterpart. A similar approach is used by Di Mascolo, Frein , Baynat and...et en Automatique , 1985. [9] Baccelli, F. and Z. Liu. "On the execution of parallel programs on multipro- cessor systems-a queuing theory approach...Le Chesnay, France: Institut National de Recherche en Informatique et en Automatique , 1986. [16] Baccelli, F., and others. "Acyclic fork-join

  6. Analytical and experimental evaluation of joining silicon carbide to silicon carbide and silicon nitride to silicon nitride for advanced heat engine applications Phase 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, G.J.; Vartabedian, A.M.; Wade, J.A.; White, C.S. [Norton Co., Northboro, MA (United States). Advanced Ceramics Div.

    1994-10-01

    The purpose of joining, Phase 2 was to develop joining technologies for HIP`ed Si{sub 3}N{sub 4} with 4wt% Y{sub 2}O{sub 3} (NCX-5101) and for a siliconized SiC (NT230) for various geometries including: butt joins, curved joins and shaft to disk joins. In addition, more extensive mechanical characterization of silicon nitride joins to enhance the predictive capabilities of the analytical/numerical models for structural components in advanced heat engines was provided. Mechanical evaluation were performed by: flexure strength at 22 C and 1,370 C, stress rupture at 1,370 C, high temperature creep, 22 C tensile testing and spin tests. While the silicon nitride joins were produced with sufficient integrity for many applications, the lower join strength would limit its use in the more severe structural applications. Thus, the silicon carbide join quality was deemed unsatisfactory to advance to more complex, curved geometries. The silicon carbide joining methods covered within this contract, although not entirely successful, have emphasized the need to focus future efforts upon ways to obtain a homogeneous, well sintered parent/join interface prior to siliconization. In conclusion, the improved definition of the silicon carbide joining problem obtained by efforts during this contract have provided avenues for future work that could successfully obtain heat engine quality joins.

  7. Analysis of Microcomposite Cu-Nb Conductors Characteristics and Possibility of Their Joining

    Directory of Open Access Journals (Sweden)

    Gediminas Mikalauskas

    2017-01-01

    Full Text Available High magnetic fields systems is widely used in fundamental and applied research in variuos branches of science and industry. The most famous examples of such magnetic systems are tokomaks, stellators, superconducting magnets, CERN collider, ITER reactor, levitation systems. The key component of magnetic systems is inductor (solenoid. At this moment, the record magnetic fields reaches 100 T. The creation of a strong magnetic field is no longer enough just to improve designs for inductor (solenoid. Traditional electrotechnical materials and conductors can no longer withstand the huge mechanical and thermal loads, therefore, them changes to an entirely new advanced materials, for example Cu-Nb microcomposite conductors. These materials are characterized by a unique structure, excellent mechanical properties and good electrical conductivity. One of the most important and unresolved problems of high magnetic fields systems are reliable non-destructive joints and joining technologies creation. This paper reviews the strong magnetic fields systems design features, Cu-Nb conductors characteristics and structure, microcomposite conductor production specifics, application fields, joining problems and the available joining technologies.

  8. Using and joining a franchised private sector provider network in Myanmar.

    Directory of Open Access Journals (Sweden)

    Kathryn O'Connell

    Full Text Available BACKGROUND: Quality is central to understanding provider motivations to join and remain within a social franchising network. Quality also appears as a key issue from the client's perspective, and may influence why a client chooses to use a franchised provider over another type of provider. The dynamic relationships between providers of social franchising clinics and clients who use these services have not been thoroughly investigated in the context of Myanmar, which has an established social franchising network. This study examines client motivations to use a Sun Quality Health network provider and provider motivations to join and remain in the Sun Quality Health network. Taken together, these two aims provide an opportunity to explore the symbiotic relationship between client satisfaction and provider incentives to increase the utilization of reproductive health care services. METHODS AND FINDINGS: Results from a series of focus group discussions with clients of reproductive health services and franchised providers shows that women chose health services provided by franchised private sector general practitioners because of its perceived higher quality, associated with the availability of effective, affordable, drugs. A key finding of the study is associated with providers. Provider focus group discussions indicate that a principle determinate for joining and remaining in the Sun Quality Health Network was serving the poor.

  9. Using and Joining a Franchised Private Sector Provider Network in Myanmar

    Science.gov (United States)

    O'Connell, Kathryn; Hom, Mo; Aung, Tin; Theuss, Marc; Huntington, Dale

    2011-01-01

    Background Quality is central to understanding provider motivations to join and remain within a social franchising network. Quality also appears as a key issue from the client's perspective, and may influence why a client chooses to use a franchised provider over another type of provider. The dynamic relationships between providers of social franchising clinics and clients who use these services have not been thoroughly investigated in the context of Myanmar, which has an established social franchising network. This study examines client motivations to use a Sun Quality Health network provider and provider motivations to join and remain in the Sun Quality Health network. Taken together, these two aims provide an opportunity to explore the symbiotic relationship between client satisfaction and provider incentives to increase the utilization of reproductive health care services. Methods and Findings Results from a series of focus group discussions with clients of reproductive health services and franchised providers shows that women chose health services provided by franchised private sector general practitioners because of its perceived higher quality, associated with the availability of effective, affordable, drugs. A key finding of the study is associated with providers. Provider focus group discussions indicate that a principle determinate for joining and remaining in the Sun Quality Health Network was serving the poor. PMID:22180781

  10. Anharmonicity and hydrogen bonding in electrooptic sucrose crystal

    Science.gov (United States)

    Szostak, M. M.; Giermańska, J.

    1990-03-01

    The polarized absorption spectra of the sucrose crystal in the 5300 - 7300 cm -1 region have been measured. The assignments of all the eight OH stretching overtones are proposed and their mechanical anharmonicities are estimated. The discrepancies from the oriented gas model (OGM) in the observed relative band intensities, especially of the -CH vibrations, are assumed to be connected with vibronic couplings enhanced by the helical arrangement of molecules joined by hydrogen bondings. It seems that this kind of interactions might be important for the second harmonic generation (SHG) by the sucrose crystal.

  11. The Ku80 carboxy terminus stimulates joining and artemis-mediated processing of DNA ends

    DEFF Research Database (Denmark)

    Weterings, Eric; Verkaik, Nicole S; Keijzers, Guido;

    2008-01-01

    Repair of DNA double-strand breaks (DSBs) is predominantly mediated by nonhomologous end joining (NHEJ) in mammalian cells. NHEJ requires binding of the Ku70-Ku80 heterodimer (Ku70/80) to the DNA ends and subsequent recruitment of the DNA-dependent protein kinase catalytic subunit (DNA-PK(CS)) an......Repair of DNA double-strand breaks (DSBs) is predominantly mediated by nonhomologous end joining (NHEJ) in mammalian cells. NHEJ requires binding of the Ku70-Ku80 heterodimer (Ku70/80) to the DNA ends and subsequent recruitment of the DNA-dependent protein kinase catalytic subunit (DNA......-PK(CS)) and the XRCC4/ligase IV complex. Activation of the DNA-PK(CS) serine/threonine kinase requires an interaction with Ku70/80 and is essential for NHEJ-mediated DSB repair. In contrast to previous models, we found that the carboxy terminus of Ku80 is not absolutely required for the recruitment and activation...... of DNA-PK(CS) at DSBs, although cells that harbored a carboxy-terminal deletion in the Ku80 gene were sensitive to ionizing radiation and showed reduced end-joining capacity. More detailed analysis of this repair defect showed that DNA-PK(CS) autophosphorylation at Thr2647 was diminished, while Ser2056...

  12. Development of a double beam process for joining aluminum and steel

    Science.gov (United States)

    Frank, Sascha

    2014-02-01

    Multi-material structures pose an attractive option for overcoming some of the central challenges in lightweight design. An exceptionally high potential for creating cost-effective lightweight solutions is attributed to the combination of steel and aluminum. However, these materials are also particularly difficult to join due to their tendency to form intermetallic compounds (IMCs). The growth of these compounds is facilitated by high temperatures and long process times. Due to their high brittleness, IMCs can severely weaken a joint. Thus, it is only possible to create durable steel-aluminum joints when the formation of IMCs can be limited to a non-critical level. To meet this goal, a new joining method has been designed. The method is based on the combination of a continuous wave (pw) and a pulsed laser (pw) source. Laser beams from both sources are superimposed in a common process zone. This makes it possible to apply the advantages of laser brazing to mixed-metal joints without requiring the use of chemical fluxes. The double beam technology was first tested in bead-on-plate experiments using different filler wire materials. Based on the results of these tests, a process for joining steel and aluminum in a double-flanged configuration is now being developed. The double flanged seams are joined using zinc- or aluminum-based filler wires. Microsections of selected seams show that it is possible to achieve good base material wetting while limiting the growth of IMCs to acceptable measures. In addition, the results of tensile tests show that high joint strengths can be achieved.

  13. Tractability results for the Double-Cut-and-Join circular median problem

    CERN Document Server

    Mahmoody-Ghaidary, Ahmad; Stacho, Ladislav

    2011-01-01

    The circular median problem in the Double-Cut-and-Join (DCJ) distance asks to find, for three given genomes, a fourth circular genome that minimizes the sum of the mutual distances with the three other ones. This problem has been shown to be NP-complete. We show here that, if the number of vertices of degree 3 in the breakpoint graph of the three input genomes is fixed, then the problem is tractable

  14. Halogen Bonding in Organic Synthesis and Organocatalysis.

    Science.gov (United States)

    Bulfield, David; Huber, Stefan M

    2016-10-01

    Halogen bonding is a noncovalent interaction similar to hydrogen bonding, which is based on electrophilic halogen substituents. Hydrogen-bonding-based organocatalysis is a well-established strategy which has found numerous applications in recent years. In light of this, halogen bonding has recently been introduced as a key interaction for the design of activators or organocatalysts that is complementary to hydrogen bonding. This Concept features a discussion on the history and electronic origin of halogen bonding, summarizes all relevant examples of its application in organocatalysis, and provides an overview on the use of cationic or polyfluorinated halogen-bond donors in halide abstraction reactions or in the activation of neutral organic substrates.

  15. Coincident In Vitro Analysis of DNA-PK-Dependent and -Independent Nonhomologous End Joining

    Directory of Open Access Journals (Sweden)

    Cynthia L. Hendrickson

    2010-01-01

    Full Text Available In mammalian cells, DNA double-strand breaks (DSBs are primarily repaired by nonhomologous end joining (NHEJ. The current model suggests that the Ku 70/80 heterodimer binds to DSB ends and recruits DNA-PKcs to form the active DNA-dependent protein kinase, DNA-PK. Subsequently, XRCC4, DNA ligase IV, XLF and most likely, other unidentified components participate in the final DSB ligation step. Therefore, DNA-PK plays a key role in NHEJ due to its structural and regulatory functions that mediate DSB end joining. However, recent studies show that additional DNA-PK-independent NHEJ pathways also exist. Unfortunately, the presence of DNA-PKcs appears to inhibit DNA-PK-independent NHEJ, and in vitro analysis of DNA-PK-independent NHEJ in the presence of the DNA-PKcs protein remains problematic. We have developed an in vitro assay that is preferentially active for DNA-PK-independent DSB repair based solely on its reaction conditions, facilitating coincident differential biochemical analysis of the two pathways. The results indicate the biochemically distinct nature of the end-joining mechanisms represented by the DNA-PK-dependent and -independent NHEJ assays as well as functional differences between the two pathways.

  16. Optimization of Friction Welding Process Parameters for Joining Carbon Steel and Stainless Steel%Optimization of Friction Welding Process Parameters for Joining Carbon Steel and Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    R Paventhan; P R Lakshminarayanan; V Balasubramanian

    2012-01-01

    Friction weIding is a solid state joining process used extensively currently owing to its advantages such as low heat input, high production efficiency, ease of manufacture, and environment friendliness. Materials difficult to be welded by fusion welding processes can be successfully welded by friction welding. An attempt was made to develop an empirical relationship to predict the tensile strength of friction welded AISI 1040 grade medium carbon steel and AISI 304 austenitic stainless steel, incorporating the process parameters such as friction pressure, forging pressure, friction time and forging time, which have great influence on strength of the joints. Response surface methodology was applied to optimize the friction welding process parameters to attain maximum tensile strength of the joint. The maximum tensile strength of 543 MPa could be obtained for the joints fabricated under the welding conditions of friction pressure of 90 MPa, forging pressure of 90 MPa, friction time of 6 s and forging time of 6 s.

  17. Malaria parasites utilize both homologous recombination and alternative end joining pathways to maintain genome integrity.

    Science.gov (United States)

    Kirkman, Laura A; Lawrence, Elizabeth A; Deitsch, Kirk W

    2014-01-01

    Malaria parasites replicate asexually within their mammalian hosts as haploid cells and are subject to DNA damage from the immune response and chemotherapeutic agents that can significantly disrupt genomic integrity. Examination of the annotated genome of the parasite Plasmodium falciparum identified genes encoding core proteins required for the homologous recombination (HR) pathway for repairing DNA double-strand breaks (DSBs), but surprisingly none of the components of the canonical non-homologous end joining (C-NHEJ) pathway were identified. To better understand how malaria parasites repair DSBs and maintain genome integrity, we modified the yeast I-SceI endonuclease system to generate inducible, site-specific DSBs within the parasite's genome. Analysis of repaired genomic DNA showed that parasites possess both a typical HR pathway resulting in gene conversion events as well as an end joining (EJ) pathway for repair of DSBs when no homologous sequence is available. The products of EJ were limited in number and identical products were observed in multiple independent experiments. The repair junctions frequently contained short insertions also found in the surrounding sequences, suggesting the possibility of a templated repair process. We propose that an alternative end-joining pathway rather than C-NHEJ, serves as a primary method for repairing DSBs in malaria parasites.

  18. Joining of Bi-2212 high- Tc superconductors and metals using indium solders

    Science.gov (United States)

    Oh, S. Y.; Kim, H. R.; Jeong, Y. H.; Hyun, O. B.; Kim, C. J.

    2007-10-01

    BSCCO tubes can be used as a base material for switching devices such as superconducting fault current limiters (SFCLs) that prevent an electrical problem from occurring in an electrical power system. To apply an BSCCO bulk tube to a switching device, the superconducting tube has to be joined with a metallic part to by the over current to the metal part when the FCL is quenched. In this study, joining between Cu-Ni alloy and BSCCO was accomplished by soldering using In-Sn and In-Bi solders. Additionally, an Sn-Ag-Cu/In-Bi solder was used for the soldering of a different kind. For a better joining of the BSCCO superconductor with the In-Bi solder, the surface of the BSCCO was pre-coated with Ag by electro-plating. From the experiments, an intermetallic compound (IMC) of AgxIny chain was observed to be mainly formed from In-Sn and In-Bi soldering process. In case of the soldering of a different kind, IMC of AgxIny and CuxSny was also developed. Finally, we confirmed that the properties of soldering were enhanced by Sn-Ag-Cu/In-Bi twice-soldering process.

  19. Joining of Bi-2212 high-T{sub c} superconductors and metals using indium solders

    Energy Technology Data Exchange (ETDEWEB)

    Oh, S.Y. [Nuclear Nanomaterials Development Laboratory, Korea Atomic Energy Research Institute (KAERI), 150 Dukjin-dong, Yusong-gu, Daejeon 305-353 (Korea, Republic of); Kim, H.R.; Jeong, Y.H.; Hyun, O.B. [Superconductivity and Applications Group, Korea Electric Power Research Institute (KEPRI), Daejeon 305-380 (Korea, Republic of); Kim, C.J. [Nuclear Nanomaterials Development Laboratory, Korea Atomic Energy Research Institute (KAERI), 150 Dukjin-dong, Yusong-gu, Daejeon 305-353 (Korea, Republic of)], E-mail: cjkim2@kaeri.re.kr

    2007-10-01

    BSCCO tubes can be used as a base material for switching devices such as superconducting fault current limiters (SFCLs) that prevent an electrical problem from occurring in an electrical power system. To apply an BSCCO bulk tube to a switching device, the superconducting tube has to be joined with a metallic part to by the over current to the metal part when the FCL is quenched. In this study, joining between Cu-Ni alloy and BSCCO was accomplished by soldering using In-Sn and In-Bi solders. Additionally, an Sn-Ag-Cu/In-Bi solder was used for the soldering of a different kind. For a better joining of the BSCCO superconductor with the In-Bi solder, the surface of the BSCCO was pre-coated with Ag by electro-plating. From the experiments, an intermetallic compound (IMC) of Ag{sub x}In{sub y} chain was observed to be mainly formed from In-Sn and In-Bi soldering process. In case of the soldering of a different kind, IMC of Ag{sub x}In{sub y} and Cu{sub x}Sn{sub y} was also developed. Finally, we confirmed that the properties of soldering were enhanced by Sn-Ag-Cu/In-Bi twice-soldering process.

  20. High energy electron beams for ceramic joining

    Energy Technology Data Exchange (ETDEWEB)

    Turman, B.N.; Glass, S.J.; Halbleib, J.A.; Helmich, D.R.; Loehman, R.E. [Sandia National Labs., Albuquerque, NM (United States); Clifford, J.R. [Titan Corp., Albuquerque, NM (United States)

    1994-12-31

    Joining of structural ceramics is possible using high melting point metals such as Mo and Pt that are heated with a high energy electron beam, with the potential for high temperature joining. A 10 MeV electron beam can penetrate through 1 cm of ceramic, offering the possibility of buried interface joining. Because of transient heating and the lower heat capacity of the metal relative to the ceramic, a pulsed high power beam has the potential for melting the metal without decomposing or melting the ceramic. We have demonstrated the feasibility of the process with a series of 10 MeV, 1 kW electron beam experiments. Shear strengths up to 28 MPa have been measured. This strength is comparable to that reported in the literature for bonding silicon nitride to molybdenum with copper-silver-titanium braze, but weaker than that reported for Si{sub 3}N{sub 4}-Si{sub 3}N{sub 4} with gold-nickel braze. The bonding mechanism appears to be a thin silicide layer.

  1. Diffusion Bonding and Characterization of a Dispersion Strengthened Aluminum Alloy

    Science.gov (United States)

    Cooke, Kavian Omar

    Aluminum metal matrix composites (Al-MMC's) containing silicon carbide or alumina particle reinforcements are used extensively in automotive and aircraft industries. The addition of a reinforcing phase has led to significant improvements in the mechanical properties of these alloys. However, despite substantial improvements in the properties, the lack of a reliable joining method has restricted their full potential. The differences in physical and metallurgical properties between the ceramic phase and the Al-MMC, prevents the successful application of the fusion welding processes, conventionally used for joining monolithic aluminum alloys. Therefore, alternative techniques that prevent microstructural changes in the base metal need to be developed. In this study, the transient liquid phase diffusion bonding and eutectic bonding of a particle reinforced Al 6061-MMC was investigated to identify a method that could control particle segregation within the joint and increase the final joint strength. The results showed that TLP bonding using Ni-foil was possible at 600°C for 10 minutes using a pressure of 0.01 MPa. However, characterization of the bond interface showed a wide particle segregated zone due to the "pushing effect" of the solid/liquid interface during isothermal solidification stage of bonding. The presence of this particle segregated zone was shown to cause low joint strengths. In order to overcome these problems, TLP bonding was performed using electrodeposited coatings of Ni and Ni-Al 2O3 as a way of controlling the volume of eutectic liquid formed at the joint. Theoretical and experimental work showed that the use of thin coatings was successful in reducing the width of the segregated zone formed at the joint and this had the effect of increasing joint shear strength values. Furthermore, lower bonding temperature could also be used as a method of reducing particle segregation and therefore, a Cu-Sn interlayer was used to form a eutectic bond. The

  2. Electrofusion joining of polyethylene gas pipes: Evaluation of pipe preparation, joining conditions and mechanical performance. Final report, 1990-1995

    Energy Technology Data Exchange (ETDEWEB)

    Grigory, S.C.; Maguire, J.F.; Deviney, M.L.

    1996-04-01

    There were three specific objectives of this research. First, a short time acceptance test for EF (electrofusion) fittings that is fundamentally related to the long time field performance was to be developed that would permit the use of existing lifetime forecasting procedures to quantify joint lifetimes. The second objective was to determine the effects of the various design and installation variables such as power input, heating time, cool-down time, initial pipe-coupler clearance and ambient temperature on the service performance. The third objective was to investigate and quantify the effects of surface preparation and cleanliness on joint integrity. Four final reports have been published to cover the diversified technology developed in this research.

  3. The boundary length and point spectrum enumeration of partial chord diagrams using cut and join recursion

    DEFF Research Database (Denmark)

    Andersen, Jørgen Ellegaard; Fuji, Hiroyuki; Penner, Robert C.

    relation, which combined with an initial condition determines these numbers uniquely. This recursion relation is equivalent to a second order, non-linear, algebraic partial differential equation for the generating function of the numbers of partial chord diagrams filtered by the boundary length and point......We introduce the boundary length and point spectrum, as a joint generalization of the boundary length spectrum and boundary point spectrum in [1]. We establish by cut-and-join methods that the number of partial chord diagrams filtered by the boundary length and point spectrum satisfies a recursion...

  4. Lateral buckling and mechanical stretchability of fractal interconnects partially bonded onto an elastomeric substrate

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Haoran [Department of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058 (China); Departments of Civil and Environmental Engineering and Mechanical Engineering, Center for Engineering and Health, Skin Disease Research Center, Northwestern University, Evanston, Illinois 60208 (United States); Xu, Sheng; Rogers, John A., E-mail: y-huang@northwestern.edu, E-mail: jrogers@illinois.edu [Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Xu, Renxiao; Huang, Yonggang, E-mail: y-huang@northwestern.edu, E-mail: jrogers@illinois.edu [Departments of Civil and Environmental Engineering and Mechanical Engineering, Center for Engineering and Health, Skin Disease Research Center, Northwestern University, Evanston, Illinois 60208 (United States); Jiang, Jianqun [Department of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058 (China); Zhang, Yihui [Departments of Civil and Environmental Engineering and Mechanical Engineering, Center for Engineering and Health, Skin Disease Research Center, Northwestern University, Evanston, Illinois 60208 (United States); Center for Mechanics and Materials, Tsinghua University, Beijing 100084 (China)

    2015-03-02

    Fractal-inspired designs for interconnects that join rigid, functional devices can ensure mechanical integrity in stretchable electronic systems under extreme deformations. The bonding configuration of such interconnects with the elastomer substrate is crucial to the resulting deformation modes, and therefore the stretchability of the entire system. In this study, both theoretical and experimental analyses are performed for postbuckling of fractal serpentine interconnects partially bonded to the substrate. The deformation behaviors and the elastic stretchability of such systems are systematically explored, and compared to counterparts that are not bonded at all to the substrate.

  5. To join or not to join: an investigation of individual facilitators and inhibitors of medical faculty participation in interdisciplinary research teams.

    Science.gov (United States)

    Salazar, Maritza; Lant, Theresa; Kane, Aimée

    2011-08-01

    Interdisciplinary research (IDR) teams are an important mechanism for facilitating medical breakthroughs. This study investigates the role of individual-level predictors of the choice to join a new IDR team at a major medical institution. We collected survey data from a sample of 233 faculty members who were given the opportunity to participate in IDR teams that had recently formed around a wide range of medical topic areas. Our results suggest that even under supportive organizational conditions, some medical experts were more likely to participate than others. Specifically, basic and translational researchers, associate professors, and faculty with distinctive topic area expertise and with more experience collaborating across departmental boundaries participated at a greater rate than their peers. Our findings have implications for research, practice, and policy focused on overcoming the challenges of drawing together diverse medical experts into IDR teams with the potential to advance knowledge to prevent, cure, and treat complex medical conditions.

  6. Cut-and-join operators and N=4 super Yang-Mills

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.W. [DESY, Hamburg (Germany). Theory Group

    2010-02-15

    We show which multi-trace structures are compatible with the symmetrisation of local operators in N=4 super Yang-Mills when they are organised into representations of the global symmetry group. Cut-and-join operators give the non-planar expansion of correlation functions of these operators in the free theory. Using these techniques we find the 1/N corrections to the quarter-BPS operators which remain protected at weak coupling. We also present a new way of counting these chiral ring operators using the Weyl group S{sub N}. (orig.)

  7. Development and Characterization of the Bonding and Integration Technologies Needed for Fabricating Silicon Carbide Based Injector Components

    Science.gov (United States)

    Halbig,Michael C.; Singh, Mrityunjay

    2008-01-01

    Advanced ceramic bonding and integration technologies play a critical role in the fabrication and application of silicon carbide based components for a number of aerospace and ground based applications. One such application is a lean direct injector for a turbine engine to achieve low NOx emissions. Ceramic to ceramic diffusion bonding and ceramic to metal brazing technologies are being developed for this injector application. For the diffusion bonding technology, titanium interlayers (coatings and foils) were used to aid in the joining of silicon carbide (SiC) substrates. The influence of such variables as surface finish, interlayer thickness, and processing time were investigated. Electron microprobe analysis was used to identify the reaction formed phases. In the diffusion bonds, an intermediate phase, Ti5Si3Cx, formed that is thermally incompatible in its thermal expansion and caused thermal stresses and cracking during the processing cool-down. Thinner interlayers of pure titanium and/or longer processing times resulted in an optimized microstructure. Tensile tests on the joined materials resulted in strengths of 13-28 MPa depending on the SiC substrate material. Nondestructive evaluation using ultrasonic immersion showed well formed bonds. For the joining technology of brazing Kovar fuel tubes to silicon carbide, preliminary development of the joining approach has begun. Various technical issues and requirements for the injector application are addressed.

  8. Semiconductors bonds and bands

    CERN Document Server

    Ferry, David K

    2013-01-01

    As we settle into this second decade of the twenty-first century, it is evident that the advances in micro-electronics have truly revolutionized our day-to-day lifestyle. The technology is built upon semiconductors, materials in which the band gap has been engineered for special values suitable to the particular application. This book, written specifically for a one semester course for graduate students, provides a thorough understanding of the key solid state physics of semiconductors. It describes how quantum mechanics gives semiconductors unique properties that enabled the micro-electronics revolution, and sustain the ever-growing importance of this revolution.

  9. Mechanical and microstructural behaviour during bonding of alumina to niobium by liquid state diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Lemus R, J.; Ramirez R, M. I.; Verduzco M, J. A.; Zarate M, J., E-mail: jlruiz@umich.mx [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigacion en Metalurgia y Materiales, Francisco Mujica s/n, 58000 Morelia, Michoacan (Mexico)

    2015-10-15

    The objective of this work was to study various aspects of liquid state diffusion bonding of cylindrical samples of Al{sub 2}O{sub 3} and commercially pure niobium (99.7%) by brazing using a 25 μm thick 70/Cu-30/Zn (wt %) alloy as joining element. Initially, sintering of alumina powder was carried out in order to produce a 7 mm diameter samples at 1550 degrees C by 60 minutes. Joining experiments were carried out on Al{sub 2}O{sub 3}/Cu-Zn/Nb/Cu-Zn/Al{sub 2}O{sub 3} sandwich-like combinations at temperature of 920, 950 and 980 degrees C using vary holding times under Ar. The experimental results show a successful joining of Al{sub 2}O{sub 3} to Nb at 950 and 980 degrees C, however not at 920 degrees C. Joining of Al{sub 2}O{sub 3}/Cu-Zn/Nb/Cu-Zn/Al{sub 2}O{sub 3} occurred by the formation of a homogeneous diffusion zone with no interfacial cracking or porosity at the interface. Scanning electron microscopy (Sem) micrographs show the layer formed in the reaction zone. It was observed that the width of the reaction zone increases with bonding temperature and time. Electron probe microanalysis (Epma) revealed that at any particular bonding temperature, Nb travel into the Cu-Zn joining element forming a circular precipitate phase near to the Al{sub 2}O{sub 3} ceramic. Shears test evaluation show results vary from 57 to 127 MPa in samples joined at 980 degrees C and time vary from 10 to 35 minutes, respectively. (Author)

  10. Fracture strength of different soldered and welded orthodontic joining configurations with and without filling material.

    Science.gov (United States)

    Bock, Jens Johannes; Bailly, Jacqueline; Gernhardt, Christian Ralf; Fuhrmann, Robert Andreas Werner

    2008-01-01

    The aim of this study was to compare the mechanical strength of different joints made by conventional brazing, TIG and laser welding with and without filling material. Five standardized joining configurations of orthodontic wire in spring hard quality were used: round, cross, 3 mm length, 9 mm length and 7 mm to orthodontic band. The joints were made by five different methods: brazing, tungsten inert gas (TIG) and laser welding with and without filling material. For the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced, totalizing 240. The fracture strengths were measured with a universal testing machine (Zwick 005). Data were analyzed by ANOVA (p=0.05) and Bonferroni post hoc test (p=0.05). In all cases, brazing joints were ruptured on a low level of fracture strength (186-407 N). Significant differences between brazing and TIG or laser welding (pfracture strength means were observed for laser welding with filling material and 3 mm joint length (998 N). Using filling materials, there was a clear tendency to higher mean values of fracture strength in TIG and laser welding. However, statistically significant differences were found only in the 9-mm long joints (pfracture strength of welded joints was positively influenced by the additional use of filling material. TIG welding was comparable to laser welding except for the impossibility of joining orthodontic wire with orthodontic band.

  11. Challenges, Ideas, and Innovations of Joined-Wing Configurations: A Concept from the Past, an Opportunity for the Future

    Science.gov (United States)

    Cavallaro, Rauno; Demasi, Luciano

    2016-11-01

    Diamond Wings, Strut- and Truss-Braced Wings, Box Wings, and PrandtlPlane, the so-called "JoinedWings", represent a dramatic departure from traditional configurations. Joined Wings are characterized by a structurally overconstrained layout which significantly increases the design space with multiple load paths and numerous solutions not available in classical wing systems. A tight link between the different disciplines (aerodynamics, flight mechanics, aeroelasticity, etc.) makes a Multidisciplinary Design and Optimization approach a necessity from the early design stages. Researchers showed potential in terms of aerodynamic efficiency, reduction of emissions and superior performances, strongly supporting the technical advantages of Joined Wings. This review will present these studies, with particular focus on the United States joined-wing SensorCraft, Strut- and Truss- Braced Wings, Box Wings and PrandtlPlane.

  12. Personal characteristics and contextual factors that determine "helping," "joining in," and "doing nothing" when witnessing cyberbullying.

    Science.gov (United States)

    Van Cleemput, Katrien; Vandebosch, Heidi; Pabian, Sara

    2014-01-01

    In this article, we investigated several determinants of bystanders' reactive behaviors when confronted with cyberbullying using self-reported data from 2,333 Flemish 9-16 year olds. Structural equation modeling showed that adolescents that had joined in on the cyberbullying were older, had lower levels of empathy and were more likely to have been involved in cyberbullying or traditional bullying as perpetrators. Adolescents who had helped the victim were younger, had higher levels of empathy and were more likely to have been a victim of cyberbullying or traditional bullying in the past months. Adolescents that did nothing when they witnessed cyberbullying, were also older, showed lower levels of empathy and were less likely to have been a victim of traditional bullying. Social anxiety was not related to joining in, helping and remaining passive. In the second part of the analysis, we found that bystanders' passive behavior could be explained in more detail by moral disengagement theory and other contextual factors. In the discussion, the implications of the findings for research on cyberbullying are addressed.

  13. Study of two different thin film coating methods in transmission laser micro-joining of thin Ti-film coated glass and polyimide for biomedical applications.

    Science.gov (United States)

    Sultana, T; Georgiev, G L; Baird, R J; Auner, G W; Newaz, G; Patwa, R; Herfurth, H J

    2009-07-01

    Biomedical devices and implants require precision joining for hermetic sealing which can be achieved with low power lasers. The effect of two different thin metal film coating methods was studied in transmission laser micro-joints of titanium-coated glass and polyimide. The coating methods were cathodic arc physical vapor deposition (CA-PVD) and electron beam evaporation (EB-PVD). Titanium-coated glass joined to polyimide film can have neural electrode application. The improvement of the joint quality will be essential for robust performance of the device. Low power fiber laser (wave length = 1100 nm) was used for transmission laser micro-joining of thin titanium (Ti) film (approximately 200 nm) coated Pyrex borosilicate 7740 glass wafer (0.5 mm thick) and polyimide (Imidex) film (0.2 mm thick). Ti film acts as the coupling agent in the joining process. The Ti film deposition rate in the CA-PVD was 5-10 A/s and in the EB-PVD 1.5 A/s. The laser joint strength was measured by a lap shear test, the Ti film surfaces were analyzed by atomic force microscopy (AFM) and the lap shear tested joints were analyzed by optical microscopy and scanning electron microscopy (SEM). The film properties and the failure modes of the joints were correlated to joint strength. The CA-PVD produced around 4 times stronger laser joints than EB-PVD. The adhesion of the Ti film on glass by CA-PVD is better than that of the EB-PVD method. This is likely to be due to a higher film deposition rate and consequently higher adhesion or sticking coefficient for the CA-PVD particles arriving on the substrate compared to that of the EB-PVD film. EB-PVD shows poor laser bonding properties due to the development of thermal hotspots which occurs from film decohesion.

  14. On the Expressiveness of Joining

    Directory of Open Access Journals (Sweden)

    Thomas Given-Wilson

    2015-08-01

    Full Text Available The expressiveness of communication primitives has been explored in a common framework based on the pi-calculus by considering four features: synchronism (asynchronous vs synchronous, arity (monadic vs polyadic data, communication medium (shared dataspaces vs channel-based, and pattern-matching (binding to a name vs testing name equality vs intensionality. Here another dimension coordination is considered that accounts for the number of processes required for an interaction to occur. Coordination generalises binary languages such as pi-calculus to joining languages that combine inputs such as the Join Calculus and general rendezvous calculus. By means of possibility/impossibility of encodings, this paper shows coordination is unrelated to the other features. That is, joining languages are more expressive than binary languages, and no combination of the other features can encode a joining language into a binary language. Further, joining is not able to encode any of the other features unless they could be encoded otherwise.

  15. Parcels and Land Ownership, Export AS400 to txt join apn, Published in 2007, McKenzie County Government.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Parcels and Land Ownership dataset as of 2007. It is described as 'Export AS400 to txt join apn'. The extent of these data is generally Mckenzie County, ND....

  16. Highly precise and developmentally programmed genome assembly in Paramecium requires ligase IV-dependent end joining.

    Directory of Open Access Journals (Sweden)

    Aurélie Kapusta

    2011-04-01

    Full Text Available During the sexual cycle of the ciliate Paramecium, assembly of the somatic genome includes the precise excision of tens of thousands of short, non-coding germline sequences (Internal Eliminated Sequences or IESs, each one flanked by two TA dinucleotides. It has been reported previously that these genome rearrangements are initiated by the introduction of developmentally programmed DNA double-strand breaks (DSBs, which depend on the domesticated transposase PiggyMac. These DSBs all exhibit a characteristic geometry, with 4-base 5' overhangs centered on the conserved TA, and may readily align and undergo ligation with minimal processing. However, the molecular steps and actors involved in the final and precise assembly of somatic genes have remained unknown. We demonstrate here that Ligase IV and Xrcc4p, core components of the non-homologous end-joining pathway (NHEJ, are required both for the repair of IES excision sites and for the circularization of excised IESs. The transcription of LIG4 and XRCC4 is induced early during the sexual cycle and a Lig4p-GFP fusion protein accumulates in the developing somatic nucleus by the time IES excision takes place. RNAi-mediated silencing of either gene results in the persistence of free broken DNA ends, apparently protected against extensive resection. At the nucleotide level, controlled removal of the 5'-terminal nucleotide occurs normally in LIG4-silenced cells, while nucleotide addition to the 3' ends of the breaks is blocked, together with the final joining step, indicative of a coupling between NHEJ polymerase and ligase activities. Taken together, our data indicate that IES excision is a "cut-and-close" mechanism, which involves the introduction of initiating double-strand cleavages at both ends of each IES, followed by DSB repair via highly precise end joining. This work broadens our current view on how the cellular NHEJ pathway has cooperated with domesticated transposases for the emergence of new

  17. Microstructural and Mechanical Evaluation of a Cu-Based Active Braze Alloy to Join Silicon Nitride Ceramics

    Science.gov (United States)

    Singh, M.; Asthana, Rajiv; Varela, F. M.; Martinez-Fernandez, J.

    2010-01-01

    Self-joining of St. Gobain Si3N4 (NT-154) using a ductile Cu-Al-Si-Ti active braze (Cu-ABA) was demonstrated. A reaction zone approx.2.5-3.5 microns thick) developed at the interface after 30 min brazing at 1317 K. The interface was enriched in Ti and Si. The room temperature compressive shear strengths of Si3N4/Si3N4 and Inconel/Inconel joints (the latter created to access baseline data for use with the proposed Si3N4/Inconel joints) were 140+/-49MPa and 207+/-12MPa, respectively. High-temperature shear tests were performed at 1023K and 1073 K, and the strength of the Si3N4/Si3N4 and Inconel/Inconel joints were determined. The joints were metallurgically well-bonded for temperatures above 2/3 of the braze solidus. Scanning and transmission electron microscopy studies revealed a fine grain microstructure in the reaction layer, and large grains in the inner part of the joint with interfaces being crack-free. The observed formation of Ti5Si3 and AlN at the joint interface during brazing is discussed.

  18. 纳米尺度连接技术的研究现状与展望%Research and application of joining technology at nanometer scale

    Institute of Scientific and Technical Information of China (English)

    何鹏; 矫震; 王君; 林铁松

    2013-01-01

    Nanomaterials have been widely applied due to their unique properties. Joining technology at nanometer scale is gradually developed with the popularity of nanomaterials, which has broad application prospects in the fields of electronics, aerospace, biology, and health care. The microscopic effects of nanomaterials were introduced and the current development of joining technology at nanometer scale were reviewed. Solid state bonding, soldering/brazing and fusion welding were mainly discussed. The differences in some phenomena and physical processes between nanoscale and macroscale were analyzed. In addition , the function of molecular dynamics simulation in nano-join-ing field was pointed out. At last, the application prospect of joining technology at nanometer scale was presented.%纳米材料以其特有的结构和性质而得到了广泛应用,纳米尺度的连接技术也随之逐渐发展起来,在电子、宇航、生物医疗等领域具有广阔的应用前景.介绍了纳米材料的微观效应,并综述了纳米尺度连接技术的研究进展,其中主要介绍了纳米固相连接、纳米钎焊和纳米熔化焊的研究现状,分析了在纳米尺度进行材料连接时,一些现象和物理过程与宏观连接时的区别,同时指出了分子动力学方法在纳米连接领域的作用,最后对纳米尺度连接技术的应用前景进行了展望.

  19. Joining Forces

    Science.gov (United States)

    Sawchuk, Stephen; Sparks, Sarah D.; Cavanagh, Sean; Samuels, Christina A.

    2011-01-01

    A mantra in recent years has been to blame the teachers' unions for many of the problems that beset public education. Americans only need look at Wisconsin, where the governor and lawmakers pushed through legislation curtailing the collective bargaining rights of teachers and other public employees. This special report examines the attempts by a…

  20. Joining Forces

    DEFF Research Database (Denmark)

    Christiansen, Anne Mette

    2013-01-01

    companies have over the last 23 years embraced the concept of strategic CSR and are increasingly engaging in cross-sector partnerships as part of their CSR strategy. The partnerships take different forms both in regards to number of partners, focus areas and level of strategic engagement. In the article......, a number of different partnerships are explored along with the motivation for the different partners for engaging. Finally, the role of a central partnership broker is examined and the author suggests that this has been instrumental in ensuring the emergence of the relatively high number of partnerships...

  1. Group-living herbivores weigh up food availability and dominance status when making patch-joining decisions.

    Directory of Open Access Journals (Sweden)

    Keenan Stears

    Full Text Available Two key factors that influence the foraging behaviour of group-living herbivores are food availability and individual dominance status. Yet, how the combination of these factors influences the patch-joining decisions of individuals foraging within groups has scarcely been explored. To address this, we focused on the patch-joining decisions of group-living domestic goats (Capra hircus. When individuals were tested against the top four ranked goats of the herd, we found that at patches with low food availability they avoided these dominant patch-holders and only joined subordinates (i.e. costs outweighed benefits. However, as the amount of food increased, the avoidance of the top ranked individuals declined. Specifically, goats shifted and joined the patch of an individual one dominance rank higher than the previous dominant patch holder when the initial quantity of food in the new patch was twice that of the lower ranking individual's patch (i.e. benefits outweighed costs. In contrast, when individuals chose between patches held by dominant goats, other than the top four ranked goats, and subordinate individuals, we found that they equally joined the dominant and subordinate patch-holders. This joining was irrespective of the dominance gap, absolute rank of the dominant patch-holder, sex or food availability (i.e. benefits outweighed costs. Ultimately, our results highlight that herbivores weigh up the costs and benefits of both food availability and patch-holder dominance status when making patch-joining decisions. Furthermore, as the initial quantity of food increases, food availability becomes more important than dominance with regard to influencing patch-joining decisions.

  2. Transient liquid phase bonding of carbon steel tubes using a Cu interlayer: Characterization and comparison with amorphous Fe–B–Si interlayer bonds

    Energy Technology Data Exchange (ETDEWEB)

    Di Luozzo, Nicolas, E-mail: nicolasdiluozzo@gmail.com [Laboratorio de Sólidos Amorfos, INTECIN, Facultad de Ingeniería, Universidad de Buenos Aires – CONICET, Paseo Colón 850, C1063ACV Buenos Aires (Argentina); Laboratoire des Matériaux et du Génie Physique (CNRS UMR 5628), Grenoble Institute of Technology, MINATEC, Grenoble Cedex 1 (France); Boudard, Michel; Doisneau, Béatrice [Laboratoire des Matériaux et du Génie Physique (CNRS UMR 5628), Grenoble Institute of Technology, MINATEC, Grenoble Cedex 1 (France); Fontana, Marcelo; Arcondo, Bibiana [Laboratorio de Sólidos Amorfos, INTECIN, Facultad de Ingeniería, Universidad de Buenos Aires – CONICET, Paseo Colón 850, C1063ACV Buenos Aires (Argentina)

    2014-12-05

    Highlights: • Cu and Fe–B–Si foils were used as interlayers to bond steel tubes by TLPB process. • The microstructure and mechanical properties were characterized. • In Cu bonded samples, the solidification process was not systematically completed. • When using Cu foils, evidences of epitaxial solidification were observed. • Tensile tests show that Cu and Fe–B–Si bonded samples failed away from the joint. - Abstract: In the present work the transient liquid phase bonding process was performed to join seamless carbon steel tubes using commercially pure Cu interlayers. The structural and mechanical characteristics of the resulting bonds are compared with those achieved using amorphous Fe–B–Si interlayers, under the same process parameters: a holding temperature of 1300 °C, a holding time of 7 min and an applied pressure of 5 MPa. The joined tubes microstructures were characterized by direct observations – scanning electron microscopy – and diffraction techniques – electron backscatter diffraction. Chemical analysis was performed using electron probe microanalysis. Whereas the amorphous Fe-B-Si interlayer leads to a completion of the bonding process over the whole bonding area, the bond performed using a Cu interlayer achieved the completion of the bonding process only partially. As the Cu is a cementite promoter, the amount of cementite coexisting with ferrite grains is higher in the joint region (JR) – corresponding to the higher concentration of Cu – as compared with the heat affected zone (HAZ) and the base metal (BM). An opposite effect is observed when using Fe-B-Si interlayers due to the fact that the cementite is unable to form in Si enriched zones – the microstructure at the JR presents only ferrite grains. Tensile tests show that the joined tubes using Cu or Fe–B–Si interlayers failed away from the bond, at the HAZ, attaining almost the same ultimate tensile strength of the BM, in the as-received condition. Hardness

  3. Strength of Bond Covenants and Bond Assessment Framework

    Directory of Open Access Journals (Sweden)

    Noel Yahanpath

    2012-06-01

    Full Text Available We examine bond covenants of 29 New Zealand bond issues between 2001 and 2007.Results from the study indicate that protection provided for bondholders is weak and limited.On average, only 2-3 types of covenants are embedded with the issues and only 27% of thesecovenants provide full protection to the bondholders. However, bondholders are not compensated for taking the additional risk. We propose an alternative assessment framework that directly assesses the level of protection offered to bondholders. We calculate thecovenant quality score for the issues and classify them into four levels of protection: very high protection, moderate, low and very low. Recent legislative changes will go some way towards improving investor protection and confidence, but the effect is yet to be seen. This proposed scoring framework can be used by potential investors to complement the traditional credit ratings when making their investment decisions.

  4. Environmentally friendly joining of tubes by their ends

    DEFF Research Database (Denmark)

    Silva, Carlos M.A.; Nielsen, Chris Valentin; Alves, Luis M.;

    2015-01-01

    This paper proposes an environmentally friendly joining process for connecting tubes by their ends that has the potential to replace current solutions based on fastened, crimped, welded, brazed or adhesive bonded joints. The process is based on a new type of tubular lap joint produced by local...... plastic instability and compression beading that has a substantial overlap with the counterfacing surfaces of the mating tubes to be joined. The presentation combines independent characterization of the materials, experimentation and numerical simulation of the process in order to identify the modes...

  5. Effect of moisture, saliva, and blood contamination on the shear bond strength of brackets bonded with a conventional bonding system and self-etched bonding system

    Science.gov (United States)

    Prasad, Mandava; Mohamed, Shamil; Nayak, Krishna; Shetty, Sharath Kumar; Talapaneni, Ashok Kumar

    2014-01-01

    Background: The success of bonding brackets to enamel with resin bonding systems is negatively affected by contamination with oral fluids such as blood and saliva. The new self-etch primer systems combine conditioning and priming agents into a single application, making the procedure more cost effective. Objective: The purpose of the study was to investigate the effect of moisture, saliva and blood contamination on shear bond strength of orthodontic brackets bonded with conventional bonding system and self-etch bonding system. Materials and Methods: Each system was examined under four enamel surface conditions (dry, water, saliva, and blood), and 80 human teeth were divided into two groups with four subgroups each of 10 according to enamel surface condition. Group 1 used conventional bonding system and Group 2 used self-etched bonding system. Subgroups 1a and 2a under dry enamel surface conditions; Subgroups 1b and 2b under moist enamel surface condition; Subgroups 3a and 3b under saliva enamel surface condition and Subgroup 4a and 4b under blood enamel surface condition. Brackets were bonded, and all the samples were then submitted to a shear bond test with a universal testing machine with a cross head speed of 1mm/sec. Results: The results showed that the contamination reduced the shear bond strength of all groups. In self-etch bonding system water and saliva had significantly higher bond strength when compared to other groups. Conclusion: It was concluded that the blood contamination showed lowest bond strength from both bonding systems. Self-etch bonding system resulted in higher bond strength than conventional bonding system under all conditions except the dry enamel surface. PMID:24678210

  6. Cooperativity in Surface Bonding and Hydrogen Bonding of Water and Hydroxyl at Metal Surfaces

    DEFF Research Database (Denmark)

    Schiros, T.; Ogasawara, H.; Naslund, L. A.;

    2010-01-01

    of the mixed phase at metal surfaces. The surface bonding can be considered to be similar to accepting a hydrogen bond, and we can thereby apply general cooperativity rules developed for hydrogen-bonded systems. This provides a simple understanding of why water molecules become more strongly bonded...... to the surface upon hydrogen bonding to OH and why the OH surface bonding is instead weakened through hydrogen bonding to water. We extend the application of this simple model to other observed cooperativity effects for pure water adsorption systems and H3O+ on metal surfaces.......We examine the balance of surface bonding and hydrogen bonding in the mixed OH + H2O overlayer on Pt(111), Cu(111), and Cu(110) via density functional theory calculations. We find that there is a cooperativity effect between surface bonding and hydrogen bonding that underlies the stability...

  7. FMEA and FTA Analyses of the Adhesive Joining Process using Electrically Conductive Adhesives

    Directory of Open Access Journals (Sweden)

    E. Povolotskaya

    2012-01-01

    Full Text Available This paper introduces a formulation of appropriate risk estimation methods that can be used for improving of processes in the electronics area. Two risk assessment methods have been chosen with regard to the specifics of adhesive joining based on electrically conductive adhesives. The paper provides a combination of a failure mode and effect analysis (FMEA and fault tree analysis (FTA for optimizing of the joining process. Typical features and failures of the process are identified. Critical operations are found and actions for avoiding failures in these actions are proposed. A fault treehas been applied to the process in order to get more precise information about the steps and operations in the process, and the relations between these operations. The fault tree identifies potential failures of the process. Then the effects of the failures have been estimated by the failure mode and effect analysis method. All major differences between failure mode and effect analysis and fault tree analysis are defined and there is a discussion about how to use the two techniquescomplement each other and achieve more efficient results.

  8. Valence-Bond Theory and Chemical Structure.

    Science.gov (United States)

    Klein, Douglas J.; Trinajstic, Nenad

    1990-01-01

    Discussed is the importance of valence bond theory on the quantum-mechanical theory of chemical structure and the nature of the chemical bond. Described briefly are early VB theory, development of VB theory, modern versions, solid-state applications, models, treatment in textbooks, and flaws in criticisms of valence bond theory. (KR)

  9. Bonds and bands in semiconductors

    CERN Document Server

    Phillips, Jim

    2009-01-01

    This classic work on the basic chemistry and solid state physics of semiconducting materials is now updated and improved with new chapters on crystalline and amorphous semiconductors. Written by two of the world's pioneering materials scientists in the development of semiconductors, this work offers in a single-volume an authoritative treatment for the learning and understanding of what makes perhaps the world's most important engineered materials actually work. Readers will find: --' The essential principles of chemical bonding, electron energy bands and their relationship to conductive and s

  10. Advanced Joining Technology

    Science.gov (United States)

    1982-01-01

    Ti-6Al-6V-2Sn, Ti-6Al-2Cb-lTa-0.8Mo (Ti-100), Ti-7Al-4Mo, Ti-6Al-2Mo-4Zr-2Sn, Ti-5Mo-4.5Al-l.5Cr ( Corona 5), and Ti-3Al-2.5Sn. Ti-6A1...Cummins Engine Company as being optimistic about the use of zirconia materials in this application. METALS (FOR JOINING TO CERAMICS) The metals of

  11. Joining of AZ31 and AZ91 Mg alloys by friction stir welding

    Directory of Open Access Journals (Sweden)

    B. Ratna Sunil

    2015-12-01

    Full Text Available Two dissimilar magnesium (Mg alloy sheets, one with low aluminium (AZ31 and another with high aluminium (AZ91 content, were successfully joined by friction stir welding (FSW. The effect of process parameters on the formation of hot cracks was investigated. A sound metallurgical joint was obtained at optimized process parameters (1400 rpm with 25 mm/min feed which contained fine grains and distributed β (Mg17Al12 phase within the nugget zone. An increasing trend in the hardness measurements has also confirmed more amount of dissolution of aluminium within the nugget zone. A sharp interface between nugget zone and thermo mechanical affected zone (TMAZ was clearly noticed at the AZ31 Mg alloy side (advancing but not on the AZ91 Mg alloy side (retreating. From the results it can be concluded that FSW can be effectively used to join dissimilar metals, particularly difficult to process metals such as Mg alloys, and hot cracking can be completely eliminated by choosing appropriate process parameters to achieve sound joint.

  12. Open intersection numbers, Kontsevich--Penner model and cut-and-join operators

    CERN Document Server

    Alexandrov, Alexander

    2014-01-01

    We continue our investigation of the Kontsevich--Penner model, which describes intersection theory on moduli spaces both for open and closed curves. In particular, we show how Buryak's residue formula, which connects two generating functions of intersection numbers, appears in the general context of matrix models and tau-functions. This allows us to prove that the Kontsevich--Penner matrix integral indeed describes open intersection numbers. For arbitrary $N$ we show that the string and dilaton equations completely specify the solution of the KP hierarchy. We derive a complete family of the Virasoro and W-constraints and using these constraints we construct the cut-and-join operators. The case $N=1$, corresponding to open intersection numbers, is particularly interesting: for this case we obtain two different families of the Virasoro constraints, so that the difference between them describes the dependence of the tau-function on even times.

  13. Approximating the double-cut-and-join distance between unsigned genomes

    Directory of Open Access Journals (Sweden)

    Yu Jiadong

    2011-10-01

    Full Text Available Abstract In this paper we study the problem of sorting unsigned genomes by double-cut-and-join operations, where genomes allow a mix of linear and circular chromosomes to be present. First, we formulate an equivalent optimization problem, called maximum cycle/path decomposition, which is aimed at finding a largest collection of edge-disjoint cycles/AA-paths/AB-paths in a breakpoint graph. Then, we show that the problem of finding a largest collection of edge-disjoint cycles/AA-paths/AB-paths of length no more than l can be reduced to the well-known degree-bounded k-set packing problem with k = 2l. Finally, a polynomial-time approximation algorithm for the problem of sorting unsigned genomes by double-cut-and-join operations is devised, which achieves the approximation ratio for any positive ε. For the restricted variation where each genome contains only one linear chromosome, the approximation ratio can be further improved to

  14. Bonded and Stitched Composite Structure

    Science.gov (United States)

    Zalewski, Bart F. (Inventor); Dial, William B. (Inventor)

    2014-01-01

    A method of forming a composite structure can include providing a plurality of composite panels of material, each composite panel having a plurality of holes extending through the panel. An adhesive layer is applied to each composite panel and a adjoining layer is applied over the adhesive layer. The method also includes stitching the composite panels, adhesive layer, and adjoining layer together by passing a length of a flexible connecting element into the plurality of holes in the composite panels of material. At least the adhesive layer is cured to bond the composite panels together and thereby form the composite structure.

  15. Fracture strength of different soldered and welded orthodontic joining configurations with and without filling material

    Directory of Open Access Journals (Sweden)

    Jens Johannes Bock

    2008-10-01

    Full Text Available The aim of this study was to compare the mechanical strength of different joints made by conventional brazing, TIG and laser welding with and without filling material. Five standardized joining configurations of orthodontic wire in spring hard quality were used: round, cross, 3 mm length, 9 mm length and 7 mm to orthodontic band. The joints were made by five different methods: brazing, tungsten inert gas (TIG and laser welding with and without filling material. For the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced, totalizing 240. The fracture strengths were measured with a universal testing machine (Zwick 005. Data were analyzed by ANOVA (p=0.05 and Bonferroni post hoc test (p=0.05. In all cases, brazing joints were ruptured on a low level of fracture strength (186-407 N. Significant differences between brazing and TIG or laser welding (p<0.05, Bonferroni post hoc test were found in each joint configuration. The highest fracture strength means were observed for laser welding with filling material and 3 mm joint length (998 N. Using filling materials, there was a clear tendency to higher mean values of fracture strength in TIG and laser welding. However, statistically significant differences were found only in the 9-mm long joints (p<0.05, Bonferroni post hoc test. In conclusion, the fracture strength of welded joints was positively influenced by the additional use of filling material. TIG welding was comparable to laser welding except for the impossibility of joining orthodontic wire with orthodontic band.

  16. Upper bound analysis for deep tunnel face with joined failure mechanism of translation and rotation

    Institute of Scientific and Technical Information of China (English)

    许敬叔; 杜佃春; 杨子汉

    2015-01-01

    A joined failure mechanism of translation and rotation was proposed for the stability analysis of deep tunnel face, and the upper bound solution of supporting force of deep tunnel was calculated under pore water pressure. The calculations were based on limit analysis method of upper bound theory, with the employment of non-associated Mohr-Coulomb flow rule. Nonlinear failure criterion was adopted. Optimized analysis was conducted for the effects of the tunnel depth, pore water pressure coefficient, the initial cohesive force and nonlinear coefficient on supporting force. The upper bound solutions are obtained by optimum method. Results are listed and compared with the previously published solutions for the verification of correctness and effectiveness. The failure shapes are presented, and results are discussed for different pore water pressure coefficients and nonlinear coefficients of tunnel face.

  17. Effects of pyrolysis temperature and fillers on joining of ceramics via silicone resin

    Institute of Scientific and Technical Information of China (English)

    SUO Jun; CHEN Zhao-hui; ZHENG Wen-wei; HAN Wei-min

    2005-01-01

    The joining of graphite, ceramic SiC and Cf/SiC composites via preceramic silicone resin(SR) at high temperature (800-1400℃) was studied. The curing and pyrolysis process of SR, pyrolysis temperature, inert and active fillers were especially discussed. The results show that the curing process of SR was accomplished by consuming Si-OH. The temperature of 1200℃ is the appropriate treating temperature for graphite and SiC ceramic, and the temperature of 1400℃ is suitable for Cf/SiC composites. Inert filler SiC powder(5%, mass fraction) has much positive influence on the shear strength of the joints. Active filler nano Ai, Si powder can greatly improve the properties of the joints treated at high temperature. The improvement is over 700%.

  18. Cut-and-join description of generalized Brezin-Gross-Witten model

    CERN Document Server

    Alexandrov, Alexander

    2016-01-01

    We investigate the Brezin-Gross-Witten model, a tau-function of the KdV hierarchy, and its natural one-parameter deformation, the generalized Brezin-Gross-Witten tau-function. In particular, we derive the Virasoro constraints, which completely specify the partition function. We solve them in terms of the cut-and-join operator. The Virasoro constraints lead to the loop equations, which we solve in terms of the correlation functions. Explicit expressions for the coefficients of the tau-function and the free energy are derived, and a compact formula for the genus zero contribution is conjectured. A family of polynomial solutions of the KdV hierarchy, given by the Schur functions, is obtained for the half-integer values of the parameter. The quantum spectral curve and its classical limit are discussed.

  19.  Optimizing relational algebra operations using discrimination-based joins and lazy products

    DEFF Research Database (Denmark)

    Henglein, Fritz

    We show how to implement in-memory execution of the core re- lational algebra operations of projection, selection and cross-product eciently, using discrimination-based joins and lazy products. We introduce the notion of (partitioning) discriminator, which par- titions a list of values according...... to a specied equivalence relation on keys the values are associated with. We show how discriminators can be dened generically, purely functionally, and eciently (worst-case linear time) on top of the array-based basic multiset discrimination algorithm of Cai and Paige (1995). Discriminators provide the basis...... the selection operation to recognize on the y whenever it is applied to a cross-product, in which case it can choose an ecient discrimination-based equijoin implementation. The techniques subsume most of the optimization techniques based on relational algebra equalities, without need for a query preprocessing...

  20. Fretting Behavior of SPR Joining Dissimilar Sheets of Titanium and Copper Alloys

    Directory of Open Access Journals (Sweden)

    Xiaocong He

    2016-12-01

    Full Text Available The fretting performance of self-piercing riveting joining dissimilar sheets in TA1 titanium alloy and H62 copper alloy was studied in this paper. Load-controlled cyclic fatigue tests were carried out using a sine waveform and in tension-tension mode. Scanning electron microscopy and energy-dispersive X-ray techniques were employed to analyze the fretting failure mechanisms of the joints. The experimental results showed that there was extremely severe fretting at the contact interfaces of rivet and sheet materials for the joints at relatively high loads levels. Moreover, the severe fretting in the region on the locked sheet in contact with the rivet was the major cause of the broken locked sheet for the joints at low load level.

  1. Diffusion bonding of copper to niobium

    Science.gov (United States)

    Wagner, Adrian R.

    Processes used to join metal to ceramic at low temperatures have proven to be inefficient because multiple brazing cycles with different brazing temperatures and braze filler metals are required. Even though this is reproducible and robust, it is not ideal due to the manufacturing time and cost associated with multiple brazing cycles. A more efficient and cost effective process is to utilize the diffusion bonding technique to join different metallic layers prior to joining the entire ceramic assembly in one brazing cycle. In this study, the diffusion bonding of copper to niobium was examined. To the author's knowledge, the diffusion bonding of Cu to Nb has not been researched, and the diffusion of Cu into Nb or Nb into Cu has not been observed. A series of diffusion bonding experiments were conducted to determine the optimal bonding time, temperature, and pressure for the Cu-Nb system. The diffusion bonded samples were evaluated using mechanical testing and microscopy. Results from characterization indicate that diffusion of Nb into Cu occurs, and a robust bond with no interfacial voids is formed using different combinations of bonding parameters. The diffusion of Nb into Cu and with failure occurring outside the diffusion bonded region during all mechanical testing indicate that Cu can be bonded to Nb via the diffusion bonding technique.

  2. Silver- and gold-mediated nucleobase bonding.

    Science.gov (United States)

    Acioli, Paulo H; Srinivas, Sudha

    2014-08-01

    We report the results of a density functional theory investigation of the bonding of nucleobases mediated by silver and gold atoms in the gas phase. Our calculations use the Becke exchange and Perdew-Wang correlation functional (BPW91) combined with the Stuttgart effective core potentials to represent the valence electrons of gold, silver, and platinum, and the all-electron DGTZVP basis set for C, H, N, and O. This combination was chosen based on tests on the metal atoms and tautomers of adenine, cytosine, and guanine. To establish a benchmark to understand the metal-mediated bonding, we calculated the binding energy of each of the base pairs in their canonical forms. Our calculations show rather strong bonds between the Watson-Crick base pairs when compared with typical values for N-H-N and N-H-O hydrogen bonds. The neutral metal atoms tend to bond near the nitrogen atoms. The effect of the metal atoms on the bonding of nucleobases differs depending on whether or not the metal atoms bond to one of the hydrogen-bonding sites. When the silver or gold atoms bond to a non-hydrogen-bonding site, the effect is a slight enhancement of the cytosine-guanine bonding, but there is almost no effect on the adenine-thymine pairing. The metal atoms can block one of the hydrogen-bonding sites, thus preventing the normal cytosine-guanine and adenine-thymine pairings. We also find that both silver and gold can bond to consecutive guanines in a similar fashion to platinum, albeit with a significantly lower binding energy.

  3. Thermal joining studies of CLIC accelerating structures and Establishment of a test bench and studies of thermomechanical behaviour of a CLIC two beam module

    CERN Document Server

    Rossi, Fabrizio

    2013-01-01

    The assembly procedure of the CLIC accelerating structures is constituted of several steps, involving ultra-precision machining, heating cycles at very high temperatures and many quality controls necessary to fulfil the very tight technical requirements. Diverse issues are related to the diffusion bonding process of CLIC accelerating structures; due to diffusion creep mechanisms occurring at high temperature and low stress, residual deformations might be present at the end of the joining process. A theoretical and experimental approach is presented here in order to understand this issue further and feedback on the design process. As a second issue tackled here, the final alignment of CLIC is also affected by the power dissipation occurring in the module during the normal operation modes and resulting in time-varying non-uniform thermal fields. The thermo-mechanical models of CLIC two-beam modules developed in the past are then useful to predict the structural deformations affecting the final alignment of the ...

  4. Generic multiset programming with discrimination-based joins and symbolic Cartesian products

    DEFF Research Database (Denmark)

    Henglein, Fritz; Larsen, Ken Friis

    2010-01-01

    : symbolic (term) repre- sentations of multisets, specifically for Cartesian products, for facilitating dynamic symbolic computation, which intersperses algebraic simplification steps with conventional data pro- cessing; and discrimination-based joins, a generic technique for computing equijoins based......This paper presents GMP, a library for generic, SQL-style programming with multisets. It generalizes the querying core of SQL in a number of ways: Multisets may contain elements of arbitrary first-order data types, including references (pointers), recur- sive data types and nested multisets...... in selections; and it allows user-defined aggregation functions. Most significantly, it avoids many cases of asymptotically inefficient nested iteration through Cartesian products that occur in a straightforward stream-based implementation of multisets. It accomplishes this by employing two novel techniques...

  5. ATRX loss promotes tumor growth and impairs nonhomologous end joining DNA repair in glioma.

    Science.gov (United States)

    Koschmann, Carl; Calinescu, Anda-Alexandra; Nunez, Felipe J; Mackay, Alan; Fazal-Salom, Janet; Thomas, Daniel; Mendez, Flor; Kamran, Neha; Dzaman, Marta; Mulpuri, Lakshman; Krasinkiewicz, Johnathon; Doherty, Robert; Lemons, Rosemary; Brosnan-Cashman, Jacqueline A; Li, Youping; Roh, Soyeon; Zhao, Lili; Appelman, Henry; Ferguson, David; Gorbunova, Vera; Meeker, Alan; Jones, Chris; Lowenstein, Pedro R; Castro, Maria G

    2016-03-02

    Recent work in human glioblastoma (GBM) has documented recurrent mutations in the histone chaperone protein ATRX. We developed an animal model of ATRX-deficient GBM and showed that loss of ATRX reduces median survival and increases genetic instability. Further, analysis of genome-wide data for human gliomas showed that ATRX mutation is associated with increased mutation rate at the single-nucleotide variant (SNV) level. In mouse tumors, ATRX deficiency impairs nonhomologous end joining and increases sensitivity to DNA-damaging agents that induce double-stranded DNA breaks. We propose that ATRX loss results in a genetically unstable tumor, which is more aggressive when left untreated but is more responsive to double-stranded DNA-damaging agents, resulting in improved overall survival.

  6. Scaling of Entanglement Entropy for the Heisenberg Model on Clusters Joined by Point Contacts

    Science.gov (United States)

    Friedman, B. A.; Levine, G. C.

    2016-11-01

    The scaling of entanglement entropy for the nearest neighbor antiferromagnetic Heisenberg spin model is studied computationally for clusters joined by a single bond. Bisecting the balanced three legged Bethe cluster, gives a second Renyi entropy and the valence bond entropy which scales as the number of sites in the cluster. For the analogous situation with square clusters, i.e. two L × L clusters joined by a single bond, numerical results suggest that the second Renyi entropy and the valence bond entropy scales as L. For both systems, the environment and the system are connected by the single bond and interaction is short range. The entropy is not constant with system size as suggested by the area law.

  7. Join Operations in Temporal Databases

    DEFF Research Database (Denmark)

    Gao, D.; Jensen, Christian Søndergaard; Snodgrass, R.T.;

    2005-01-01

    , if any, comparison of the various operators. We then address evaluation algorithms, comparing the applicability of various algorithms to the temporal join operators and describing a performance study involving algorithms for one important operator, the temporal equijoin. Our focus, with respect......Joins are arguably the most important relational operators. Poor implementations are tantamount to computing the Cartesian product of the input relations. In a temporal database, the problem is more acute for two reasons. First, conventional techniques are designed for the evaluation of joins...... with equality predicates rather than the inequality predicates prevalent in valid-time queries. Second, the presence of temporally varying data dramatically increases the size of a database. These factors indicate that specialized techniques are needed to efficiently evaluate temporal joins. We address...

  8. Blind-date Conversation Joining

    Directory of Open Access Journals (Sweden)

    Luca Cesari

    2013-07-01

    Full Text Available We focus on a form of joining conversations among multiple parties in service-oriented applications where a client may asynchronously join an existing conversation without need to know in advance any information about it. More specifically, we show how the correlation mechanism provided by orchestration languages enables a form of conversation joining that is completely transparent to clients and that we call 'blind-date joining'. We provide an implementation of this strategy by using the standard orchestration language WS-BPEL. We then present its formal semantics by resorting to COWS, a process calculus specifically designed for modelling service-oriented applications. We illustrate our approach by means of a simple, but realistic, case study from the online games domain.

  9. Analytical and Experimental Evaluation of Joining Silicon Carbide to Silicon Carbide and Silicon Nitride to Silicon Nitride for Advanced Heat Engine Applications Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, G.J.

    1994-01-01

    Techniques were developed to produce reliable silicon nitride to silicon nitride (NCX-5101) curved joins which were used to manufacture spin test specimens as a proof of concept to simulate parts such as a simple rotor. Specimens were machined from the curved joins to measure the following properties of the join interlayer: tensile strength, shear strength, 22 C flexure strength and 1370 C flexure strength. In parallel, extensive silicon nitride tensile creep evaluation of planar butt joins provided a sufficient data base to develop models with accurate predictive capability for different geometries. Analytical models applied satisfactorily to the silicon nitride joins were Norton's Law for creep strain, a modified Norton's Law internal variable model and the Monkman-Grant relationship for failure modeling. The Theta Projection method was less successful. Attempts were also made to develop planar butt joins of siliconized silicon carbide (NT230).

  10. RECQ HELICASE RECQL4 PARTICIPATES IN NON-HOMOLOGOUS END JOINING AND INTERACTS WITH THE KU COMPLEX

    DEFF Research Database (Denmark)

    Shamanna, Raghavendra A; Singh, Dharmendra Kumar; Lu, Huiming

    2014-01-01

    RECQL4, a member of the RecQ helicase family, is a multifunctional participant in DNA metabolism. RECQL4 protein participates in several functions both in the nucleus and in the cytoplasm of the cell, and mutations in human RECQL4 are associated with three genetic disorders: Rothmund......-Thomson, RAPADILINO and Baller-Gerold syndromes. We previously reported that RECQL4 is recruited to laser-induced DNA double-strand breaks (DSB). Here, we have characterized the functional roles of RECQL4 in the non-homologous end joining (NHEJ) pathway of DSB repair. In an in vitro NHEJ assay that depends...... on the activity of DNA-PK, extracts from RECQL4 knockdown cells display reduced end-joining activity on DNA substrates with cohesive and non-cohesive ends. Depletion of RECQL4 also reduced the end joining activity on a GFP reporter plasmid in vivo. Knockdown of RECQL4 increased the sensitivity of cells to γ...

  11. Decomposing European bond and equity volatility

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    The paper investigates volatility spillover from US and aggregate European asset markets into European national asset markets. A main contribution is that bond and equity volatilities are analyzed simultaneously. A new model belonging to the "volatilityspillover" family is suggested......: The conditional variance of e.g. the unexpected German stock return is divided into separate effects from the contemporaneous idiosyncratic variance of US bonds, US stocks, European bonds, European stocks, German bonds, and German stocks. Significant volatility-spillover effects are found. The national bond...... (stock) volatilities are mainly influenced by bond (stock) effects. Global, regional, and local volatility effects are all important. The introduction of the euro is associated with a structural break....

  12. Design of Helical Self-Piercing Rivet for Joining Aluminum Alloy and High-Strength Steel Sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kim, W. Y.; Kim, D. B.; Park, J. G; Kim, D. H.; Kim, K. H.; Lee, I. H.; Cho, H. Y. [Chungbuk National University, Cheongju (Korea, Republic of)

    2014-07-15

    A self-piercing rivet (SPR) is a mechanical component for joining dissimilar material sheets such as those of aluminum alloy and steel. Unlike conventional rivets, the SPR directly pierces sheets without the need for drilling them beforehand. However, the regular SPR can undergo buckling when it pierces a high-strength steel sheet, warranting the design of a helical SPR. In this study, the joining and forging processes using the helical SPR were simulated using the commercial FEM code, DEFORM-3D. High-tensile-strength steel sheets of different strengths were joined with aluminum alloy sheets using the designed helical SPR. The simulation results were found to agree with the experimental results, validating the optimal design of a helical SPR that can pierce high-strength steel sheets.

  13. Desperately seeking fusion: on 'joined-up thinking', 'holistic practice' and the new economy of welfare professional power.

    Science.gov (United States)

    Allen, Chris

    2003-06-01

    This paper argues that social welfare research on joined-up thinking is underpinned by two theses. The 'systemic move' thesis suggests that joined-up thinking is needed to fill gaps in welfare service provision arising from a lack of interorganizational co-ordination. The 'epistemological move' thesis advises that joined-up thinking is needed to overcome deficiencies in the institutional division and distribution of welfare knowledge. Both theses macro-systematize blame for previous social welfare failures, and both are teleological because they present joined-up thinking as a progressive solution that results in a more effective (and thus less fallible) welfare system. In this paper, I argue thatjoined-up thinking can also create a new economy of welfare professional power. First, I show how some versions of 'joined-up' thinking manifest themselves in holistic practices that can 'see everything', 'know everything' and 'do anything', and thus a 'holistic power' to discipline and control every aspect of welfare recipients lives. Since holistic power is seen as infallible, its failure to produce 'active bodies' necessitates the creation of secondary 'joined-up powers' that individualize blame and exclude those to blame from welfare resources. These 'secondary powers' match the social disciplines enforced by one welfare agency (e.g. the responsibility to work enforced by the employment service) with legal rights under another agency (e.g. the right to housing from social landlords), so that breach of the former leads to exclusion from the latter. I conclude that this power strategy is primitive and punitive because it simply excludes welfare recipients. Exclusion is also uneconomic because it pushes welfare recipients into the shade of welfare institutional power.

  14. Processing of pro-opiomelanocortin-derived amidated joining peptide and glycine-extended precursor in monkey pituitary

    DEFF Research Database (Denmark)

    Fenger, M

    1991-01-01

    The molecular forms of proopiomelanocortin (POMC) derived amidated and C-terminal glycine-extended joining peptide from monkey (Macaca mulatta) pituitary were determined. The predominant forms of joining peptide found were the low molecular peptides POMC(76-105) and POMC(76-106), respectively...... sequence of monkey and human POMC extremely conserved, but also the processing patterns are similar. The monkey therefore serves as a suitable model for studying regulation of the processing of POMC and the hypothalamus-pituitary-adrenal axis in man....

  15. Constructing Models in Teaching of Chemical Bonds: Ionic Bond, Covalent Bond, Double and Triple Bonds, Hydrogen Bond and Molecular Geometry

    Science.gov (United States)

    Uce, Musa

    2015-01-01

    Studies in chemistry education show that chemistry topics are considered as abstract, complicated and hard to understand by students. For this reason, it is important to develop new materials and use them in classes for better understanding of abstract concepts. Moving from this point, a student-centered research guided by a teacher was conducted…

  16. Amidated joining peptide in the human pituitary, gut, adrenal gland and bronchial carcinoids. Immunocytochemical and immunochemical evidence

    DEFF Research Database (Denmark)

    Bjartell, A; Fenger, M; Ekman, R;

    1990-01-01

    The distribution of the proopiomelanocortin-derivated amidated joining peptide (JP-N) was examined in the human pituitary gland, adrenal gland, gut and in three bronchial carcinoids. Double immunostaining showed coexistence of immunoreactive JP-N and other proopiomelanocortin derivatives, e...

  17. Fatigue strength testing of LTCC and alumina ceramics bonds

    Science.gov (United States)

    Dąbrowski, A.; Matkowski, P.; Golonka, L.

    2012-12-01

    In this paper the results of fatigue strength tests of ceramic joints are presented. These tests have been performed on the samples subjected to thermal and vibration fatigue as well as on the reference samples without any additional loads. The main goal of the investigation was to determine the strength of hybrid ceramics joints using tensile testing machine. The experiment enabled evaluation of fatigue effects in the mentioned joints. Geometry of test samples has been designed according to FEM simulations, performed in ANSYS FEM environment. Thermal stress as well as the stress induced by vibrations have been analyzed in the designed model. In the experiments two types of ceramics have been used — LTCC green tape DP951 (DuPont) and alumina ceramic tape. The samples have been prepared by joining two sintered ceramic beams made of different types of material. The bonds have been realized utilizing low temperature glass or a layer of LTCC green tape.

  18. Childhood exposure to violence and lifelong health: Clinical intervention science and stress biology research join forces

    Science.gov (United States)

    Moffitt, Terrie E.

    2013-01-01

    Many young people who are mistreated by an adult, victimized by bullies, criminally assaulted, or who witness domestic violence react to this violence exposure by developing behavioral, emotional, or learning problems. What is less well known is that adverse experiences like violence exposure can lead to hidden physical alterations inside a child’s body, alterations which may have adverse effects on life-long health. We discuss why this is important for the field of developmental psychopathology and for society, and we recommend that stress-biology research and intervention science join forces to tackle the problem. We examine the evidence base in relation to stress-sensitive measures for the body (inflammatory reactions, telomere erosion, epigenetic methylation, and gene expression) and brain (mental disorders, neuroimaging, and neuropsychological testing). We also review promising interventions for families, couples, and children that have been designed to reduce the effects of childhood violence exposure. We invite intervention scientists and stress-biology researchers to collaborate in adding stress-biology measures to randomized clinical trials of interventions intended to reduce effects of violence exposure and other traumas on young people. PMID:24342859

  19. Why Children Join and Stay in Sports Clubs: Case Studies in Australian, French and German Swimming Clubs

    Science.gov (United States)

    Light, Richard L.; Harvey, Stephen; Memmert, Daniel

    2013-01-01

    This article builds upon research on youth sport clubs conducted from a socio-cultural perspective by reporting on a study that inquired into the reasons why children aged 9-12 joined swimming clubs in France, Germany and Australia. Comprising three case studies it employed a mixed method approach with results considered within the framework of…

  20. Shear bond strength of ceramic and metallic orthodontic brackets bonded with self-etching primer and conventional bonding adhesives

    Science.gov (United States)

    Arash, Valiollah; Naghipour, Fatemeh; Ravadgar, Mehdi; Karkhah, Ahmad; Barati, Mohammad Saleh

    2017-01-01

    Introduction Adult patients typically require high-quality orthodontic treatment for ceramic brackets, but some clinicians remain concerned about the bond strength of these brackets. Therefore, the aim of this study was to determine the shear bond strength and de-bonding characteristics of metallic and ceramic brackets bonded with two types of bonding agents. Methods In an experimental study done in 2013 in Babol, Iran, 120 extracted human maxillary premolar teeth were randomly divided into four groups as follows: HM group: metallic bracket/conventional bonding agent; SM group: metallic bracket/Transbond self-etching primer; HC group: ceramic bracket/conventional bonding agent; SC group: ceramic bracket/Transbond self-etching primer. Twenty-four hours after thermocycling (1000 cycle, 5 °C–55 °C), the shear bond strength values were measured. The amount of resin remaining on the tooth surface (adhesive remnant index: ARI) was determined under a stereomicroscope. Enamel detachment index was evaluated under a scanning electron microscope. To perform statistical analysis, ANOVA, Kruskal–Wallis, and Tukey post-hoc tests were applied. The level of significance was set at p ceramic brackets. In addition, self-etching primer was able to produce fewer bonds compared with the conventional technique. Many samples showed the bracket-adhesive interface failure or failure inside the adhesive. PMID:28243410

  1. Transient liquid phase bonding of magnesium alloys AZ31 using nickel coatings and high frequency induction heat sintering

    Directory of Open Access Journals (Sweden)

    A.N. AlHazaa

    2016-04-01

    Full Text Available Transient liquid phase (TLP bonding process was applied to join magnesium alloy AZ31 samples with minimum microstructural changes. The magnesium samples were coated by 5 μm nickel prior to the TLP bonding. Bonding conditions of 8 MPa uniaxial pressure and 520 °C bonding temperature were applied for all bonds at various bonding times. The microstructure across the joint regions was examined as a function of bonding time (5–60 min. Investigating the change in Ni contents was examined by EDS line scan. It was noticed that Ni coating could not be observed by SEM for bonds made at 30 and 60 min due to complete dissolution of the Ni coating. Second phase particles containing Mg2Ni intermetallics were observed by X-ray Photoelectron Spectroscopy (XPS near the joint region. The shear strength of the bonds initially increases with the increase in bonding time till 20 min. On the other hand, with bonding times over 20 min the shear strength decreases. Therefore the optimum bonding time at the conditions applied was concluded to be 20 min.

  2. The Nature of the Hydrogen Bond Outline of a Comprehensive Hydrogen Bond Theory

    CERN Document Server

    Gilli, Gastone

    2009-01-01

    Hydrogen bond (H-bond) effects are known: it makes sea water liquid, joins cellulose microfibrils in trees, shapes DNA into genes and polypeptide chains into wool, hair, muscles or enzymes. Its true nature is less known and we may still wonder why O-H...O bond energies range from less than 1 to more than 30 kcal/mol without apparent reason. This H-bond puzzle is re-examined here from its very beginning and presented as an inclusive compilation of experimental H-bond energies andgeometries.New concepts emerge from this analysis: new classes of systematically strong H-bonds (CAHBs and RAHBs: cha

  3. Bibliography of the technical literature of the Materials Joining Group, Metals and Ceramics Division, 1951 through June 1987

    Energy Technology Data Exchange (ETDEWEB)

    David, S.A.; Goodwin, G.M.; Gardner, K. (comps.)

    1987-08-01

    This document contains a listing of the written scientific information originating in the Materials Joining Group (formerly the Welding and Brazing Group), Metals and Ceramics Division, Oak Ridge National Laboratory during 1951 through June 1987. It is a registry of about 400 documents as nearly as possible in the order in which they were issued.

  4. DNA ligases I and III cooperate in alternative non-homologous end-joining in vertebrates.

    Directory of Open Access Journals (Sweden)

    Katja Paul

    Full Text Available Biochemical and genetic studies suggest that vertebrates remove double-strand breaks (DSBs from their genomes predominantly by two non-homologous end joining (NHEJ pathways. While canonical NHEJ depends on the well characterized activities of DNA-dependent protein kinase (DNA-PK and LIG4/XRCC4/XLF complexes, the activities and the mechanisms of the alternative, backup NHEJ are less well characterized. Notably, the contribution of LIG1 to alternative NHEJ remains conjectural and although biochemical, cytogenetic and genetic experiments implicate LIG3, this contribution has not been formally demonstrated. Here, we take advantage of the powerful genetics of the DT40 chicken B-cell system to delineate the roles of LIG1 and LIG3 in alternative NHEJ. Our results expand the functions of LIG1 to alternative NHEJ and demonstrate a remarkable ability for LIG3 to backup DSB repair by NHEJ in addition to its essential function in the mitochondria. Together with results on DNA replication, these observations uncover a remarkable and previously unappreciated functional flexibility and interchangeability between LIG1 and LIG3.

  5. In vivo analysis of Cajal body movement, separation, and joining in live human cells.

    Science.gov (United States)

    Platani, M; Goldberg, I; Swedlow, J R; Lamond, A I

    2000-12-25

    Cajal bodies (also known as coiled bodies) are subnuclear organelles that contain specific nuclear antigens, including splicing small nuclear ribonucleoproteins (snRNPs) and a subset of nucleolar proteins. Cajal bodies are localized in the nucleoplasm and are often found at the nucleolar periphery. We have constructed a stable HeLa cell line, HeLa(GFP-coilin), that expresses the Cajal body marker protein, p80 coilin, fused to the green fluorescent protein (GFP-coilin). The localization pattern and biochemical properties of the GFP-coilin fusion protein are identical to the endogenous p80 coilin. Time-lapse recordings on 63 nuclei of HeLa(GFP-coilin) cells showed that all Cajal bodies move within the nucleoplasm. Movements included translocations through the nucleoplasm, joining of bodies to form larger structures, and separation of smaller bodies from larger Cajal bodies. Also, we observed Cajal bodies moving to and from nucleoli. The data suggest that there may be at least two classes of Cajal bodies that differ in their size, antigen composition, and dynamic behavior. The smaller size class shows more frequent and faster rates of movement, up to 0.9 microm/min. The GFP-coilin protein is dynamically associated with Cajal bodies as shown by changes in their fluorescence intensity over time. This study reveals an unexpectedly high level of movement and interactions of nuclear bodies in human cells and suggests that these movements may be driven, at least in part, by regulated mechanisms.

  6. Comparison of nonhomologous end joining and homologous recombination in human cells

    Science.gov (United States)

    Mao, Zhiyong; Bozzella, Michael; Seluanov, Andrei; Gorbunova, Vera

    2009-01-01

    The two major pathways for repair of DNA double-strand breaks (DSBs) are homologous recombination (HR) and nonhomologous end joining (NHEJ). HR leads to accurate repair, while NHEJ is intrinsically mutagenic. To understand human somatic mutation it is essential to know the relationship between these pathways in human cells. Here we provide a comparison of the kinetics and relative contributions of HR and NHEJ in normal human cells. We used chromosomally integrated fluorescent reporter substrates for real-time in vivo monitoring of the NHEJ and HR. By examining multiple integrated clones we show that the efficiency of NHEJ and HR is strongly influenced by chromosomal location. Furthermore, we show that NHEJ of compatible ends (NHEJ-C) and NHEJ of incompatible ends (NHEJ-I) are fast processes, which can be completed in approximately 30 min, while HR is much slower and takes 7h or longer to complete. In actively cycling cells NHEJ-C is twice as efficient as NHEJ-I, and NHEJ-I is three times more efficient than HR. Our results suggest that NHEJ is a faster and more efficient DSB repair pathway than HR. PMID:18675941

  7. Emergence and oscillation of cosmic space by joining M1-branes

    CERN Document Server

    Sepehri, Alireza; Capozziello, Salvatore; Ali, Ahmed Farag; Pradhan, Anirudh

    2016-01-01

    Recently, it has been proposed by Padmanabhan that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region leads to the expansion of the universe. Now, a natural question arises, how this model could explain the oscillation of universe between contraction and expansion branches? We try to address this issue in the framework of BIonic system. In this model, $M0$-branes join to each other and give rise to a pair of $M1$-anti-$M1$-branes. The fields which live on these branes play the roles of massive gravitons that cause the emergence of a wormhole between them and formation of a BIon system. This wormhole dissolves into M1-branes and causes a divergence between the number of degrees of freedom on the boundary surface of $M1$ and the bulk leading to an expansion of $M1$-branes. When $M1$-branes become close to each other, the square energy of their system becomes negative and some tachyonic states emerge. To removes these states, $M1$...

  8. Optimising query execution time in LHCb Bookkeeping System using partition pruning and Partition-Wise joins

    Science.gov (United States)

    Mathe, Zoltan; Charpentier, Philippe

    2014-06-01

    The LHCb experiment produces a huge amount of data which has associated metadata such as run number, data taking condition (detector status when the data was taken), simulation condition, etc. The data are stored in files, replicated on the Computing Grid around the world. The LHCb Bookkeeping System provides methods for retrieving datasets based on their metadata. The metadata is stored in a hybrid database model, which is a mixture of Relational and Hierarchical database models and is based on the Oracle Relational Database Management System (RDBMS). The database access has to be reliable and fast. In order to achieve a high timing performance, the tables are partitioned and the queries are executed in parallel. When we store large amounts of data the partition pruning is essential for database performance, because it reduces the amount of data retrieved from the disk and optimises the resource utilisation. This research presented here is focusing on the extended composite partitioning strategy such as range-hash partition, partition pruning and usage of the Partition-Wise joins. The system has to serve thousands of queries per minute, the performance and capability of the system is measured when the above performance optimization techniques are used.

  9. Halogen bonding origin properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Hobza, Pavel [Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague (Czech Republic); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Palacky University, 77146 Olomouc (Czech Republic)

    2015-12-31

    σ-hole bonding represents an unusual and novel type of noncovalent interactions in which atom with σ- hole interacts with Lewis base such as an electronegative atom (oxygen, nitrogen, …) or aromatic systems. This bonding is of electrostatic nature since the σ-hole bears a positive charge. Dispersion energy forms equally important energy term what is due to the fact that two heavy atoms (e.g. halogen and oxygen) having high polarizability lie close together (the respective distance is typically shorter than the sum of van der Waals radii). Among different types of σ-hole bondings the halogen bonding is by far the most known but chalcogen and pnictogen bondings are important as well.

  10. A Single-Lap Joint Adhesive Bonding Optimization Method Using Gradient and Genetic Algorithms

    Science.gov (United States)

    Smeltzer, Stanley S., III; Finckenor, Jeffrey L.

    1999-01-01

    A natural process for any engineer, scientist, educator, etc. is to seek the most efficient method for accomplishing a given task. In the case of structural design, an area that has a significant impact on the structural efficiency is joint design. Unless the structure is machined from a solid block of material, the individual components which compose the overall structure must be joined together. The method for joining a structure varies depending on the applied loads, material, assembly and disassembly requirements, service life, environment, etc. Using both metallic and fiber reinforced plastic materials limits the user to two methods or a combination of these methods for joining the components into one structure. The first is mechanical fastening and the second is adhesive bonding. Mechanical fastening is by far the most popular joining technique; however, in terms of structural efficiency, adhesive bonding provides a superior joint since the load is distributed uniformly across the joint. The purpose of this paper is to develop a method for optimizing single-lap joint adhesive bonded structures using both gradient and genetic algorithms and comparing the solution process for each method. The goal of the single-lap joint optimization is to find the most efficient structure that meets the imposed requirements while still remaining as lightweight, economical, and reliable as possible. For the single-lap joint, an optimum joint is determined by minimizing the weight of the overall joint based on constraints from adhesive strengths as well as empirically derived rules. The analytical solution of the sin-le-lap joint is determined using the classical Goland-Reissner technique for case 2 type adhesive joints. Joint weight minimization is achieved using a commercially available routine, Design Optimization Tool (DOT), for the gradient solution while an author developed method is used for the genetic algorithm solution. Results illustrate the critical design variables

  11. Scientific collaboration between 'old' and 'new' member states: Did joining the European Union make a difference?

    Science.gov (United States)

    Makkonen, Teemu; Mitze, Timo

    This paper provides new insights on the effects of the enlargement of the European Union (EU) and European integration by investigating the issue of scientific collaboration within the new EU member states vis-à-vis the old EU member states. The question addressed is whether the EU membership following the two enlargement waves 2004 and 2007 has significantly increased the co-publication intensity of the new member states with other member countries. The empirical results based on data collected from the Web of Science database and Difference-in-Difference estimations point towards a conclusion that joining the EU indeed has had an additional positive impact on the co-publication intensity between the new and old member states and, in particular, within the new member states themselves. These results give tentative support for the successfulness of the EU's science policies in achieving a common 'internal market' in research. We also find evidence for early anticipation effects of the consecutive EU accession.

  12. Tungsten joining with copper alloy and its high heat load performance

    Science.gov (United States)

    Liu, Xiang; Lian, Youyun; Chen, Lei; Cheng, Zengkui; Chen, Jiming; Duan, Xuru; Song, Jioupeng; Yu, Yang

    2014-12-01

    W-CuCrZr joining technology by using low activation Cu-Mn filler metal was developed at Southwestern Institute of Physics (SWIP) for the manufacturing of divertor components of fusion experiment devices. In addition, a fast W coating technology by chemical vapor deposition (CVD) was also developed and CVD-W/CuCrZr and CVD-W/C mockups with a W coating thickness of 2 mm were prepared. In order to assess their high heat flux (HHF) performances, a 60 kW Electron-beam Material testing Scenario (EMS-60) equipped with a 150 keV electron beam welding gun was constructed at SWIP. Experimental results indicated that brazed W/CuCrZr mockups can withstand 8 MW/m2 heat flux for 1000 cycles without visible damages and CVD-W/CuCrZr mockups with W-Cu gradient interface can survive 1000 cycles under 11 MW/m2 heat flux. An ultrasonic inspection method for non-destructive tests (NDT) of brazed W/CuCrZr mockups was established and 2 mm defect can be detected. Infinite element analysis and heat load tests indicated that 5 mm defect had less noticeable influence on the heat transfer.

  13. An Ocean Reanalysis System for the Joining Area of Asia and Indian-Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    YAN Chang-Xiang; ZHU Jiang; XIE Ji-Ping

    2010-01-01

    An ocean reanalysis system for the joining area of Asia and Indian-Pacific Ocean(AIPO)has been developed and is currently delivering reanalysis data sets for study on the air-sea interaction over AIPO and its climate variation over China in the inter-annual time scale.This system consists of a nested ocean model forced by atmospheric reanalysis,an ensemble-based multivariate ocean data assimilation system and various ocean observations.The following report describes the main components of the data assimilation system in detail.The system adopts an ensemble optimal interpolation scheme that uses a seasonal update from a free running model to estimate the background error covariance matrix.In view of the systematic biases in some observation systems,some treatments were performed on the observations before the assimilation.A coarse resolution reanalysis dataset from the system is preliminarily evaluated to demonstrate the performance of the system for the period 1992 to 2006 by comparing this dataset with other observations or reanalysis data.

  14. Effect of Surface States on Joining Mechanisms and Mechanical Properties of Aluminum Alloy (A5052 and Polyethylene Terephthalate (PET by Dissimilar Friction Spot Welding

    Directory of Open Access Journals (Sweden)

    Farazila Yusof

    2016-04-01

    Full Text Available In this research, polyethylene terephthalate (PET, as a high-density thermoplastic sheet, and Aluminum A5052, as a metal with seven distinct surface roughnesses, were joined by friction spot welding (FSW. The effect of A5052’s various surface states on the welding joining mechanism and mechanical properties were investigated. Friction spot welding was successfully applied for the dissimilar joining of PET thermoplastics and aluminum alloy A5052. During FSW, the PET near the joining interface softened, partially melted and adhered to the A5052 joining surface. The melted PET evaporated to form bubbles near the joining interface and cooled, forming hollows. The bubbles have two opposite effects: its presence at the joining interface prevent PET from contacting with A5052, while bubbles or hollows are crack origins that induce crack paths which degrade the joining strength. On the other hand, the bubbles’ flow pushed the softened PET into irregularities on the roughened surface to form mechanical interlocking, which significantly improved the strength. The tensile-shear failure load for an as-received surface (0.31 μ m Ra specimen was about 0.4–0.8 kN while that for the treated surface (>0.31 μ m Ra specimen was about 4.8–5.2 kN.

  15. Efficient Privacy Preserving Protocols for Similarity Join

    Directory of Open Access Journals (Sweden)

    Bilal Hawashin

    2012-04-01

    Full Text Available During the similarity join process, one or more sources may not allow sharing its data with other sources. In this case, a privacy preserving similarity join is required. We showed in our previous work [4] that using long attributes, such as paper abstracts, movie summaries, product descriptions, and user feedbacks, could improve the similarity join accuracy using supervised learning. However, the existing secure protocols for similarity join methods can not be used to join sources using these long attributes. Moreover, the majority of the existing privacy‐preserving protocols do not consider the semantic similarities during the similarity join process. In this paper, we introduce a secure efficient protocol to semantically join sources when the join attributes are long attributes. We provide two secure protocols for both scenarios when a training set exists and when there is no available training set. Furthermore, we introduced the multi‐label supervised secure protocol and the expandable supervised secure protocol. Results show that our protocols can efficiently join sources using the long attributes by considering the semantic relationships among the long string values. Therefore, it improves the overall secure similarity join performance.

  16. 'Joined Up' Local Governments?

    DEFF Research Database (Denmark)

    Bjørnå, Hilde; Casale, Donatella; Hajnal, Gyorgy;

    eforms inspired by NPM have raised many challenges to governments, such as time lags between implementation and (any) results, fragmentation due to unbundling monolithic organizations and mediocre support from public sector stakeholders (Christensen/Lægreid 2007, Dunleavy et al. 2006, Hood....../Dixon 2015). In addition, singular events like the current financial crisis (Peters 2011) shed a new light on previous reforms. Today we find that 'Joined-up government' (JUG) modernization programs (as one strand of Post-NPM) are increasingly implemented as a reaction to the dysfunctionalities of NPM...... measures (6 2004). JUG involves an emphasis on coordinating governmental activities, for example through partnerships and horizontal governing approaches, to eliminate contradictions between different policies, and to deliver integrated and seamless services from a citizen’s perspective (Lægreid et al...

  17. DNA repair and gene targeting in plant end-joining mutants

    NARCIS (Netherlands)

    Jia, Qi

    2011-01-01

    DNA double-strand breaks (DSBs) can be repaired by homologous recombination (HR) or by non-homologous end joining (NHEJ). The latter mechanism is the major route for DSB repair in the somatic cells of higher eukaryotes, including plants. If we could manipulate the balance of the DSB repair pathways

  18. Evaluation of shear bond strength of porcelain bonded to laser welded titanium surface and determination of mode of bond failure.

    Science.gov (United States)

    Patil, Narendra P; Dandekar, Minal; Nadiger, Ramesh K; Guttal, Satyabodh S

    2010-09-01

    The aim of this study was to evaluate the shear bond strength of porcelain to laser welded titanium surface and to determine the mode of bond failure through scanning electron microscopy (SEM) and energy dispersive spectrophotometry (EDS). Forty five cast rectangular titanium specimens with the dimension of 10 mm x 8 mm x 1 mm were tested. Thirty specimens had a perforation of 2 mm diameter in the centre. These were randomly divided into Group A and B. The perforations in the Group B specimens were repaired by laser welding using Cp Grade II titanium wire. The remaining 15 specimens were taken as control group. All the test specimens were layered with low fusing porcelain and tested for shear bond strength. The debonded specimens were subjected to SEM and EDS. Data were analysed with 1-way analysis of variance and Student's t-test for comparison among the different groups. One-way analysis of variance (ANOVA) showed no statistically significant difference in shear bond strength values at a 5% level of confidence. The mean shear bond strength values for control group, Group A and B was 8.4 +/- 0.5 Mpa, 8.1 +/- 0.4 Mpa and 8.3 +/- 0.3 Mpa respectively. SEM/EDS analysis of the specimens showed mixed and cohesive type of bond failure. Within the limitations of the study laser welding did not have any effect on the shear bond strength of porcelain bonded to titanium.

  19. Comparison of scaffold-enhanced albumin and n-butyl-cyanoacrylate adhesives for joining of tissue in a porcine model

    Science.gov (United States)

    McNally-Heintzelman, Karen M.; Riley, Jill N.; Heintzelman, Douglas L.

    2003-06-01

    An ex vivo study was conducted to compare the tensile strength of tissue samples repaired using three different techniques: (i) application of a scaffold-enhanced light-activated albumin protein solder, (ii) application of a scaffold-enhanced n-butyl-cyanoacrylate adhesive, and (iii) repair via conventional suture technique. Biodegradable polymer scaffolds of controlled porosity were fabricated with poly(L-lactic-co-glycolic acid) and salt particles using a solvent-casting and particulate-leaching technique. Group I porous scaffolds were doped with protein solder composed of 50%(w/v) bovine serum albumin solder and 0.5mg/ml indocyanine green dye mixed in deionized water, and activated with an 808-nm diode laser. Group II scaffolds were doped with n-butyl-cyanoacrylate, and required no light-activation. No stay sutures were required for Group I or II experiments. Group III repairs were performed using a single 4-0 suture. Thirteen organs were tested ranging from skin to liver to the small intestine, as well as the coronary, pulmonary, carotid, femoral and splenic arteries. Acute breaking strengths were measured and the data were analyzed by Student"s T-test. Using the protein solder of Group I, repairs formed on the ureter were most successful followed by small intestine, sciatic nerve, spleen, atrium, kidney, muscle, skin and ventricle. The strongest vascular repairs were achieved in the carotid artery and femoral artery. Overall, the tensile strength of Group III repairs performed via suture techniques were equivalent in magnitude to that of Group I repairs, however, a larger variance was observed in the suture repair group. Group II repairs utilizing the cyanoacrylate-doped scaffold all performed extremely well. Bonds formed using the Group II adhesive were approximately 30% stronger than Group I and III organ repairs and approximately 20% stronger than Group I and III vascular repairs. Application of the polymer scaffold assists in tissue alignment and reduces

  20. HYDROGEN BONDING IN POLYMERIC ADSORBENTS BASED ADSORPTION AND SEPARATION

    Institute of Scientific and Technical Information of China (English)

    XUMancai; SHIZuoqing; 等

    2000-01-01

    After a concise introduction of hydrogen bonding effects in solute-solute and solute-solvent bonding,the design of polymeric adsorbents based on hydrogen bonding ,selectivity in adsorption through hydrogen bonding,and characterization of hydrogen bonding in adsorption and separation were reviewed with 28 references.

  1. Emergence and oscillation of cosmic space by joining M1-branes

    Science.gov (United States)

    Sepehri, Alireza; Rahaman, Farook; Capozziello, Salvatore; Ali, Ahmed Farag; Pradhan, Anirudh

    2016-05-01

    Recently, it has been proposed by Padmanabhan that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region leads to the expansion of the universe. Now, a natural question arises; how could this model explain the oscillation of the universe between contraction and expansion branches? We try to address this issue in the framework of a BIonic system. In this model, M0-branes join to each other and give rise to a pair of M1-anti- M1-branes. The fields which live on these branes play the roles of massive gravitons that cause the emergence of a wormhole between them and formation of a BIon system. This wormhole dissolves into M1-branes and causes a divergence between the number of degrees of freedom on the boundary surface of M1 and the bulk leading to an expansion of M1-branes. When M1-branes become close to each other, the square energy of their system becomes negative and some tachyonic states emerge. To remove these states, M1-branes become compact, the sign of compacted gravity changes, causing anti-gravity to arise: in this case, branes get away from each other. By articulating M1-BIons, an M3-brane and an anti- M3-brane are created and connected by three wormholes forming an M3-BIon. This new system behaves like the initial system and by closing branes to each other, they become compact and, by getting away from each other, they open. Our universe is located on one of these M3-branes and, by compactifying the M3-brane, it contracts and, by opening it, it expands.

  2. Emergence and oscillation of cosmic space by joining M1-branes

    Energy Technology Data Exchange (ETDEWEB)

    Sepehri, Alireza [Shahid Bahonar University, Faculty of Physics, Kerman (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Rahaman, Farook [Jadavpur University, Department of Mathematics, Kolkata, West Bengal (India); Capozziello, Salvatore [Universita di Napoli Federico II, Dipartimento di Fisica ' ' E. Pancini' ' , Naples (Italy); Gran Sasso Science Institute (INFN), L' Aquila (Italy); Tomsk State Pedagogical University, Tomsk (Russian Federation); INFN Sezione di Napoli, Naples (Italy); Ali, Ahmed Farag [Benha University, Department of Physics, Faculty of Science, Benha (Egypt); Pradhan, Anirudh [G L A University, Department of Mathematics, Institute of Applied Sciences and Humanities, Mathura, Uttar Pradesh (India)

    2016-05-15

    Recently, it has been proposed by Padmanabhan that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region leads to the expansion of the universe. Now, a natural question arises; how could this model explain the oscillation of the universe between contraction and expansion branches? We try to address this issue in the framework of a BIonic system. In this model, M0-branes join to each other and give rise to a pair of M1-anti-M1-branes. The fields which live on these branes play the roles of massive gravitons that cause the emergence of a wormhole between them and formation of a BIon system. This wormhole dissolves into M1-branes and causes a divergence between the number of degrees of freedom on the boundary surface of M1 and the bulk leading to an expansion of M1-branes. When M1-branes become close to each other, the square energy of their system becomes negative and some tachyonic states emerge. To remove these states, M1-branes become compact, the sign of compacted gravity changes, causing anti-gravity to arise: in this case, branes get away from each other. By articulating M1-BIons, an M3-brane and an anti-M3-brane are created and connected by three wormholes forming an M3-BIon. This new system behaves like the initial system and by closing branes to each other, they become compact and, by getting away from each other, they open. Our universe is located on one of these M3-branes and, by compactifying the M3-brane, it contracts and, by opening it, it expands. (orig.)

  3. Innovative Structural and Joining Concepts for Lightweight Design of Heavy Vehicle Systems

    Energy Technology Data Exchange (ETDEWEB)

    Jacky C. Prucz; Samir N. Shoukry; Gergis W. William

    2005-08-31

    heavy vehicles. The research work planed for the first year of this project (June 1, 2003 through May 30, 2004) focused on a theoretical investigation of weight benefits and structural performance tradeoffs associated with the design, fabrication, and joining of MMC components for heavy-duty vehicles. This early research work conducted at West Virginia University yielded the development of integrated material-structural models that predicted marginal benefits and significant barriers to MMC applications in heavy trailers. The results also indicated that potential applications of MMC materials in heavy vehicles are limited to components identified as critical for either loadings or weight savings. Therefore, the scope of the project was expanded in the following year (June 1, 2004 through May 30, 2005) focused on expanding the lightweight material-structural design concepts for heavy vehicles from the component to the system level. Thus, the following objectives were set: (1) Devise and evaluate lightweight structural configurations for heavy vehicles. (2) Study the feasibility of using Metal Matrix Composites (MMC) for critical structural components and joints in heavy vehicles. (3) Develop analysis tools, methods, and validated test data for comparative assessments of innovative design and joining concepts. (4) Develop analytical models and software for durability predictions of typical heavy vehicle components made of particulate MMC or fiber-reinforced composites. This report summarizes the results of the research work conducted during the past two years in this projects.

  4. Expected Business Conditions and Bond Risk Premia

    DEFF Research Database (Denmark)

    Eriksen, Jonas Nygaard

    2015-01-01

    This paper studies the predictability of bond risk premia by means of expectations to future business conditions using survey forecasts from the Survey of Professional Forecasters. We show that expected business conditions consistently affect excess bond returns and that the inclusion of expected...... business conditions in standard predictive regressions improve forecast performance relative to models using information derived from the current term structure or macroeconomic variables. The results are confirmed in a real-time out-of-sample exercise, where the models predictive accuracy are evaluated...... both statistically and from the perspective of a mean-variance investor that trades in the bond market....

  5. Expected Business Conditions and Bond Risk Premia

    DEFF Research Database (Denmark)

    Eriksen, Jonas Nygaard

    This paper studies the predictability of bond risk premia by means of expectations to future business conditions using survey forecasts from the Survey of Professional Forecasters. We show that expected business conditions consistently affect excess bond returns and that the inclusion of expected...... business conditions in standard predictive regressions improve forecast performance relative to models using information derived from the current term structure or macroeconomic variables. The results are confirmed in a real-time out-of-sample exercise, where the predictive accuracy of the models...... is evaluated both statistically and from the perspective of a mean-variance investor that trades in the bond market....

  6. DNA repair by nonhomologous end joining and homologous recombination during cell cycle in human cells

    Science.gov (United States)

    Mao, Zhiyong; Bozzella, Michael; Seluanov, Andrei; Gorbunova, Vera

    2009-01-01

    DNA double-strand breaks (DSBs) are dangerous lesions that can lead to potentially oncogenic genomic rearrangements or cell death. The two major pathways for repair of DSBs are nonhomologous end joining (NHEJ) and homologous recombination (HR). NHEJ is an intrinsically error-prone pathway while HR results in accurate repair. To understand the origin of genomic instability in human cells it is important to know the contribution of each DSB repair pathway. Studies of rodent cells and human cancer cell lines have shown that the choice between NHEJ or HR pathways depends on cell cycle stage. Surprisingly, cell cycle regulation of DSB repair has not been examined in normal human cells with intact cell cycle checkpoints. Here we measured the efficiency of NHEJ and HR at different cell cycle stages in hTERT-immortalized diploid human fibroblasts. We utilized cells with chromosomally-integrated fluorescent reporter cassettes, in which a unique DSB is introduced by a rare-cutting endonuclease. We show that NHEJ is active throughout the cell cycle, and its activity increases as cells progress from G1 to G2/M (G1and declines in G2/M. Thus, in G2/M NHEJ is elevated, while HR is on decline. This is in contrast to a general belief that NHEJ is most active in G1, while HR is active in S, G2 and M. The overall efficiency of NHEJ was higher than HR at all cell cycle stages. We conclude that human somatic cells utilize error-prone NHEJ as the major DSB repair pathway at all cell cycle stages, while HR is used, primarily, in the S phase. PMID:18769152

  7. Mechatronic modeling and simulation using bond graphs

    CERN Document Server

    Das, Shuvra

    2009-01-01

    Bond graphs are especially well-suited for mechatronic systems, as engineering system modeling is best handled using a multidisciplinary approach. Bond graphing permits one to see the separate components of an engineering system as a unified whole, and allows these components to be categorized under a few generalized elements, even when they come from different disciplines. In addition to those advantages, the bond graph offers a visual representation of a system from which derivation of the governing equations is algorithmic. This makes the design process accessible to beginning readers, prov

  8. 53BP1 regulates DNA resection and the choice between classical and alternative end joining during class switch recombination.

    Science.gov (United States)

    Bothmer, Anne; Robbiani, Davide F; Feldhahn, Niklas; Gazumyan, Anna; Nussenzweig, Andre; Nussenzweig, Michel C

    2010-04-12

    Class switch recombination (CSR) diversifies antibodies by joining highly repetitive DNA elements, which are separated by 60-200 kbp. CSR is initiated by activation-induced cytidine deaminase, an enzyme that produces multiple DNA double-strand breaks (DSBs) in switch regions. Switch regions are joined by a mechanism that requires an intact DNA damage response and classical or alternative nonhomologous end joining (A-NHEJ). Among the DNA damage response factors, 53BP1 has the most profound effect on CSR. We explore the role of 53BP1 in intrachromosomal DNA repair using I-SceI to introduce paired DSBs in the IgH locus. We find that the absence of 53BP1 results in an ataxia telangiectasia mutated-dependent increase in DNA end resection and that resected DNA is preferentially repaired by microhomology-mediated A-NHEJ. We propose that 53BP1 favors long-range CSR in part by protecting DNA ends against resection, which prevents A-NHEJ-dependent short-range rejoining of intra-switch region DSBs.

  9. Join Cost for Unit Selection Speech Synthesis

    OpenAIRE

    Vepa, Jithendra

    2004-01-01

    Undoubtedly, state-of-the-art unit selection-based concatenative speech systems produce very high quality synthetic speech. this is due to a large speech database containing many instances of each speech unit, with a varied and natural distribution of prosodic and spectral characteristics. the join cost, which measures how well two units can be joined together is one of the main criteria for selecting appropriate units from this large speech database. The ideal join cost is one that measur...

  10. The Effect of Temperature on Shear Bond Strength of Clearfil SE Bond and Adper Single Bond Adhesive Systems to Dentin

    Directory of Open Access Journals (Sweden)

    Hossein Nouri

    2015-03-01

    Full Text Available Statement of the Problem: Monomer viscosity and solvent evaporation can be affected by the adhesive system temperature. Higher temperature can elevate the vapor pressure in solution and penetration of adhesive in smear layer. Bonding mechanism may be influenced by the adhesive temperature. Purpose: This study aimed to evaluate the effect of pre-heating on shear bond strength of etch-and-rinse and self-etching adhesives to ground bovine dentin surfaces, at temperatures of 4˚C, 25˚C and 40˚C. Materials and Method: In this experimental study, 60 maxillary bovine incisors were randomly divided into 6 groups (n=10. The central part of labial dentin surfaces was exposed with a diamond bur and standardized smear layer was creat-ed by using silicon carbide paper (600 grit under water-coolant while the specimens were mounted in acrylic resin. Two adhesive systems, an etch-and-rinse (Adper single bond and a self-etch (Clearfil SE Bond were stored at temperatures of 4˚C, 25˚C and 40˚C for 30 minutes and were then applied on the prepared labial surface according to the manufacturer’s instructions. The composite resin (Z350 was packed in Teflon mold (5 mm in diameter on this surface and was cured. The shear bond strength (MPa was evaluated by universal testing machine (Zwick/Roell Z020, Germany at cross head speed of 1mm/min. The results were statistically analyzed by using ANOVA and Tukey tests (p< 0.05. Results: No significant difference was found between the shear bond strength of Clearfil SE Bond adhesive in different temperature and single Bond adhesive sys-tem at 25 ̊C and 40 ̊C. However, there were significant differences between 4 ̊C of Adper single bond in comparison with 25˚C and 40˚C (p= 0.0001. Conclusion: Pre-heating did not affect the shear bond strength of SE Bond, but could promote the shear bond strength of Adper Single Bond.

  11. Fundamental aspects of recoupled pair bonds. I. Recoupled pair bonds in carbon and sulfur monofluoride

    Energy Technology Data Exchange (ETDEWEB)

    Dunning, Thom H., E-mail: thdjr@uw.edu; Xu, Lu T.; Takeshita, Tyler Y. [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801 (United States)

    2015-01-21

    The number of singly occupied orbitals in the ground-state atomic configuration of an element defines its nominal valence. For carbon and sulfur, with two singly occupied orbitals in their {sup 3}P ground states, the nominal valence is two. However, in both cases, it is possible to form more bonds than indicated by the nominal valence—up to four bonds for carbon and six bonds for sulfur. In carbon, the electrons in the 2s lone pair can participate in bonding, and in sulfur the electrons in both the 3p and 3s lone pairs can participate. Carbon 2s and sulfur 3p recoupled pair bonds are the basis for the tetravalence of carbon and sulfur, and 3s recoupled pair bonds enable sulfur to be hexavalent. In this paper, we report generalized valence bond as well as more accurate calculations on the a{sup 4}Σ{sup −} states of CF and SF, which are archetypal examples of molecules that possess recoupled pair bonds. These calculations provide insights into the fundamental nature of recoupled pair bonds and illustrate the key differences between recoupled pair bonds formed with the 2s lone pair of carbon, as a representative of the early p-block elements, and recoupled pair bonds formed with the 3p lone pair of sulfur, as a representative of the late p-block elements.

  12. Water, Hydrogen Bonding and the Microwave Background

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2009-04-01

    Full Text Available n this work, the properties of the water are briefly revisited. Though liquid water has a fleeting structure, it displays an astonishingly stable network of hydrogen bonds. Thus, even as a liquid, water possesses a local lattice with short range order. The presence of hydroxyl (O-H and hydrogen (H....OH2 bonds within water, indicate that it can simultaneously maintain two separate energy systems. These can be viewed as two very different temperatures. The analysis presented uses results from vibrational spec- troscopy, extracting the force constant for the hydrogen bonded dimer. By idealizing this species as a simple diatomic structure, it is shown that hydrogen bonds within wa- ter should be able to produce thermal spectra in the far infrared and microwave regions of the electromagnetic spectrum. This simple analysis reveals that the oceans have a physical mechanism at their disposal, which is capable of generating the microwave background.

  13. Gap measurement and bond strength of five selected adhesive systems bonded to tooth structure.

    Science.gov (United States)

    Arbabzadeh, F; Gage, J P; Young, W G; Shahabi, S; Swenson, S M

    1998-06-01

    The ability of a restorative material to bond and seal the interface with tooth structure is perhaps the most significant factor in determining resistance to marginal caries. Thus, the quality and durability of marginal seal and bond strength are major considerations in the selection of restorative materials. The purpose of this study was to compare the bond strength and marginal discrepancies of five adhesive systems: All-Bond 2, Clearfil Liner Bond, KB 200, ProBond and AELITE Bond. Twenty-five buccal and 25 lingual cavities were prepared in 25 caries-free extracted molar teeth, giving 10 cavities for each of the 5 adhesive systems. All teeth were restored with the resin composite Pertac Hybrid, or PRISMA Total Performance Hybrid with their appropriate adhesive systems. After restoration, the teeth were thermocycled, were stained with a 1.5% aqueous solution of a procion dye (reactive orange 14) and sectioned coronally with a saw microtome. Three sections of 200 microns thickness were prepared from each restoration which were then examined microscopically to measure marginal gap widths using a confocal tandem microscope. Shear bond strength measurements were carried out on the dentine bond using a universal testing machine. The All-Bond 2 adhesive system was found to have higher shear bond strength and to have the least gap width at the cementodentinal margin.

  14. Bibliography of the technical literature of the Materials Joining Group, Metals and Ceramics Division, 1951--June 1989

    Energy Technology Data Exchange (ETDEWEB)

    David, S.A.; Goodwin, G.M.; Gardner, K. (comps.)

    1989-10-01

    This document contains a listing of the written scientific information originating in the Materials Joining (formerly the Welding and Brazing Group), Metals and Ceramics Division, Oak Ridge National Laboratory during 1951 through June 1989. This registry of documents is as much as possible, in the order of issue date. A complete cross-referenced listing of the technical literature of the Metals and Ceramics Division is also available.

  15. Correlation of Fe2+ isomer shifts with bond lengths and bond strengths in neso- and sorosilicates

    Institute of Scientific and Technical Information of China (English)

    李哲; E.DeGrave

    1995-01-01

    An evaluation of Mbssbauer isomer shift and quadrupole splitting data of Fe2+ in a number of structurally well characterized neso- and sorosilicates is presented. It is found that the nearly linear correlations exist both between the isomer shift and the bond length and between the isomer shift and the bond strength. These correlations are discussed on the basis of the variation of the s-electron density at the Fe2+ nuclei with the chemical bond characteristics.

  16. Nonhomologous DNA end joining and chromosome aberrations in human embryonic lung fibroblasts treated with environmental pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Rossner, Pavel, E-mail: prossner@biomed.cas.cz; Rossnerova, Andrea; Beskid, Olena; Tabashidze, Nana; Libalova, Helena; Uhlirova, Katerina; Topinka, Jan; Sram, Radim J.

    2014-05-15

    Highlights: • We analyzed the effect of air pollutants on NHEJ and chromosome aberrations. • In HEL12469 cells B[a]P and extractable organic matter induced DSBs. • The compounds induced XRCC4 expression and a weak Ku70/80 response. • We found increased frequency of aberrations of chromosomes 1, 2, 4, 5, 7 and 17. • The tested compounds preferentially affected chromosome 7. - Abstract: In order to evaluate the ability of a representative polycyclic aromatic hydrocarbon (PAH) and PAH-containing complex mixtures to induce double strand DNA breaks (DSBs) and repair of damaged DNA in human embryonic lung fibroblasts (HEL12469 cells), we investigated the effect of benzo[a]pyrene (B[a]P) and extractable organic matter (EOM) from ambient air particles <2.5 μm (PM2.5) on nonhomologous DNA end joining (NHEJ) and induction of stable chromosome aberrations (CAs). PM2.5 was collected in winter and summer 2011 in two Czech cities differing in levels and sources of air pollutants. The cells were treated for 24 h with the following concentrations of tested chemicals: B[a]P: 1 μM, 10 μM, 25 μM; EOMs: 1 μg/ml, 10 μg/ml, 25 μg/ml. We tested several endpoints representing key steps leading from DSBs to the formation of CAs including histone H2AX phosphorylation, levels of proteins Ku70, Ku80 and XRCC4 participating in NHEJ, in vitro ligation activity of nuclear extracts of the HEL12469 cells and the frequency of stable CAs assessed by whole chromosome painting of chromosomes 1, 2, 4, 5, 7 and 17 using fluorescence in situ hybridization. Our results show that 25 μM of B[a]P and most of the tested doses of EOMs induced DSBs as indicated by H2AX phosphorylation. DNA damage was accompanied by induction of XRCC4 expression and an increased frequency of CAs. Translocations most frequently affected chromosome 7. We observed only a weak induction of Ku70/80 expression as well as ligation activity of nuclear extracts. In summary, our data suggest the induction of DSBs and

  17. Definition and Application of Topological Index Based on Bond Connectivity

    Institute of Scientific and Technical Information of China (English)

    WANG Zhen-dong; YANG Feng; YANG Hai-lang; LUO Ming-dao; QU Song-sheng

    2003-01-01

    Bond connectivity topological index Si based on chemical bonds was defined by using a matrix method.And Si is formed by atomic parameters such as the number of valence electrons,the number of the highest main quantum of atoms and the bonding electrons and bond parameters such as the length of bonds,the electronegativity difference of bonding atoms.The molecular bond connectivity topological index S is composed of Si.The thermodynamic properties of saturated hydrocarbons,unsaturated hydrocarbons,oxygen organic,methane halide and transitional element compounds and the molecular bond connectivity topological index S have an optimal correlative relationship.

  18. [Morita Therapy to Treat Depression: When and How to Encourage Patients to Join Activities].

    Science.gov (United States)

    Nakamura, Kei

    2015-01-01

    The author discusses how Morita therapy is used to treat depression, illustrated with a clinical case, and makes comparisons between Morita therapy and behavioral activation (BA). The author further examines the issue of when and how to encourage patients to join activities in clinical practice in Japan. Both Morita therapy and BA share at least a common view that it is effective to activate patients' constructive behavior at a certain point in depression treatment. However, BA therapists, compared to Morita therapists, seem to pay less attention to the necessity of resting and the appropriate timing for introducing behavioral activation. There may be some contextual differences between depressive patients in Japan and those in North America. In the case of Japanese patients, exhaustion from overwork is often considered a factor triggering the development of depression. At the same time, the Morita-based pathogenic model of depression seems different from BA's model of the same disorder. BA's approach to understanding depression may be considered a psychological (behavioristic) model. In this model, the cause of depression lies in: (a) a lack of positive reinforcement, and (b) negative reinforcement resulting from avoidance of the experience of discomfort. Therefore, the basic strategy of BA is to release depressive patients from an avoidant lifestyle, which serves as a basis for negative reinforcement, and to redirect the patients toward activities which offer the experience of positive reinforcement BA is primarily practiced by clinical psychologists in the U. S. while psychiatrists prescribe medication as a medical service. On the other hand, the clinical practice of treating depression in Japan is based primarily on medical models of depression. This is also true of Morita therapy, but in a broad sense. While those who follow medical models in a narrow sense try to identify the cause of illness and then remove it, Morita therapists pay more attention to the

  19. Dissimilar Joining of ODS and F/M Steel Tube by Friction Stir Welding

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Suk Hoon; Noh, Sanghoon; Kim, Jun Hwan; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    martensite, and the oxide particles are uniformly distributed as the mechanical alloying (MA) process. FSW was successfully applied for joining of tube and end-plug.

  20. Fork-join and data-driven execution models on multi-core architectures: Case study of the FMM

    KAUST Repository

    Amer, Abdelhalim

    2013-01-01

    Extracting maximum performance of multi-core architectures is a difficult task primarily due to bandwidth limitations of the memory subsystem and its complex hierarchy. In this work, we study the implications of fork-join and data-driven execution models on this type of architecture at the level of task parallelism. For this purpose, we use a highly optimized fork-join based implementation of the FMM and extend it to a data-driven implementation using a distributed task scheduling approach. This study exposes some limitations of the conventional fork-join implementation in terms of synchronization overheads. We find that these are not negligible and their elimination by the data-driven method, with a careful data locality strategy, was beneficial. Experimental evaluation of both methods on state-of-the-art multi-socket multi-core architectures showed up to 22% speed-ups of the data-driven approach compared to the original method. We demonstrate that a data-driven execution of FMM not only improves performance by avoiding global synchronization overheads but also reduces the memory-bandwidth pressure caused by memory-intensive computations. © 2013 Springer-Verlag.

  1. Facile fabrication of magnetically recyclable metal-organic framework nanocomposites for highly efficient and selective catalytic oxidation of benzylic C-H bonds.

    Science.gov (United States)

    Chen, Yifa; Huang, Xianqiang; Feng, Xiao; Li, Jikun; Huang, Yingyu; Zhao, Jingshu; Guo, Yuexin; Dong, Xinmei; Han, Ruodan; Qi, Pengfei; Han, Yuzhen; Li, Haiwei; Hu, Changwen; Wang, Bo

    2014-08-07

    HKUST-1@Fe3O4 chemically bonded core-shell nanoparticles have been prepared by growing HKUST-1 thin layers joined by carboxyl groups onto Fe3O4 nanospheres. These magnetic core-shell MOF nanostructures show exceptional catalytic activity for the oxidation of benzylic C-H bonds and they can be recovered by magnetic separation and reused without losing any activity.

  2. Composite Bonding to Stainless Steel Crowns Using a New Universal Bonding and Single-Bottle Systems

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Hattan

    2013-01-01

    Full Text Available Aim. The aim of this study is to evaluate the shear bond strength of nanocomposite to stainless steel crowns using a new universal bonding system. Material and Methods. Eighty (80 stainless steel crowns (SSCs were divided into four groups (20 each. Packable nanocomposite was bonded to the lingual surface of the crowns in the following methods: Group A without adhesive (control group, Group B using a new universal adhesive system (Scotchbond Universal Adhesive, 3M ESPE, Seefeld, Germany, and Group C and Group D using two different brands of single-bottle adhesive systems. Shear bond strengths were calculated and the types of failure also were recorded. Results. The shear strength of Group B was significantly greater than that of other groups. No significant differences were found between the shear bond strengths of Groups C and D. The control group had significantly lower shear bond strength ( to composite than the groups that utilized bonding agents. Conclusion. Composites bonding to stainless steel crowns using the new universal bonding agent (Scotchbond Universal Adhesive, 3M ESPE, Seefeld, Germany show significantly greater shear bond strengths and fewer adhesive failures when compared to traditional single-bottle systems.

  3. Electronic structure and bonding in crystalline peroxides

    Science.gov (United States)

    Königstein, Markus; Sokol, Alexei A.; Catlow, C. Richard A.

    1999-08-01

    Hartree-Fock and density-functional PW91 theories as realized in the CRYSTAL95 code have been applied to investigate the structural and electronic properties of Ba, Sr, and Ca peroxide materials with the calcium carbide crystal structure, results for which are compared with those for the corresponding oxides. Special attention is paid to the stabilization of the peroxide molecular ion O2-2 in the ionic environment provided by the lattice, and to chemical bonding effects. In order to describe the covalent bonding within the O2-2 ion and the polarization of the O- ion in the crystal electrostatic field, it is essential to include an account of the effects of electron correlation. The PW91 density functional has allowed us to reproduce the crystallographic parameters within a 3% error. The chemical bonding within the peroxide molecular ion has a complex nature with a balance between the weak covalent bond of σz type and the strong electrostatic repulsion of the closed-shell electron groups occupying O 2s and O 2px and 2py states. Compression of the peroxide ion in the ionic crystals gives rise to an excessive overlap of the O 2s closed shells of the two O- ions of a peroxide molecular ion O2-2, which in turn determines the antibonding character of the interaction and chemical bonding in the O2-2 molecular ion.

  4. Proceedings of the Symposium on Welding, Bonding, and Fastening. [production engineering for aircraft and spacecraft structures

    Science.gov (United States)

    Stein, B. A. (Compiler); Buckley, J. D. (Compiler)

    1972-01-01

    Various technological processes to achieve lightweight reliable joining systems for structural elements of aircraft and spacecraft are considered. Joining methods, combinations of them, and nondestructive evaluation and quality assurance are emphasized.

  5. Bonding theory for metals and alloys

    CERN Document Server

    Wang, Frederick E

    2005-01-01

    Bonding Theory for Metals and Alloys exhorts the potential existence of covalent bonding in metals and alloys. Through the recognition of the covalent bond in coexistence with the 'free' electron band, the book describes and demonstrates how the many experimental observations on metals and alloys can all be reconciled. Subsequently, it shows how the individual view of metals and alloys by physicists, chemists and metallurgists can be unified. The physical phenomena of metals and alloys covered in this book are: Miscibility Gap between two liquid metals; Phase Equilibrium Diagrams; Phenomenon of Melting. Superconductivity; Nitinol; A Metal-Alloy with Memory; Mechanical Properties; Liquid Metal Embrittlement; Superplasticity; Corrosion; The author introduces a new theory based on 'Covalon' conduction, which forms the basis for a new approach to the theory of superconductivity. This new approach not only explains the many observations made on the phenomenon of superconductivity but also makes predictions that ha...

  6. Bond strength, bond stress and spallation mechanisms of thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Gell, M.; Krishnakumar, V.; McCarron, K.; Barber, B.; Sohn, Y.-H. [Connecticut Univ., Storrs, CT (United States). Dept. of Metall. and Mater. Eng.; Eric, J. [Connecticut Univ., Storrs, CT (United States). Dept. of Mechanical Engineering; Tolpygo, V.K.

    1999-11-01

    Five production thermal barrier coatings were thermally cycled between room temperature and 1121 C (2050 F) to determine relative spallation life. Bond strength measurements were made using a modified ASTM direct pull-test. Bond stress measurements were made in the thermally grown oxide using a laser photoluminescence technique. Bond strength and bond stress measurements were conducted on two electron beam physical vapor deposition coatings as a function of thermal cycling. Each coating showed characteristic values of as-coated strength and stress and changes in strength and stress with thermal cycling. These variations in strength and stress with thermal cycling are related to oxidation and micro-debonding effects. (orig.)

  7. Efficient Joins with Compressed Bitmap Indexes

    Energy Technology Data Exchange (ETDEWEB)

    Computational Research Division; Madduri, Kamesh; Wu, Kesheng

    2009-08-19

    We present a new class of adaptive algorithms that use compressed bitmap indexes to speed up evaluation of the range join query in relational databases. We determine the best strategy to process a join query based on a fast sub-linear time computation of the join selectivity (the ratio of the number of tuples in the result to the total number of possible tuples). In addition, we use compressed bitmaps to represent the join output compactly: the space requirement for storing the tuples representing the join of two relations is asymptotically bounded by min(h; n . cb), where h is the number of tuple pairs in the result relation, n is the number of tuples in the smaller of the two relations, and cb is the cardinality of the larger column being joined. We present a theoretical analysis of our algorithms, as well as experimental results on large-scale synthetic and real data sets. Our implementations are efficient, and consistently outperform well-known approaches for a range of join selectivity factors. For instance, our count-only algorithm is up to three orders of magnitude faster than the sort-merge approach, and our best bitmap index-based algorithm is 1.2x-80x faster than the sort-merge algorithm, for various query instances. We achieve these speedups by exploiting several inherent performance advantages of compressed bitmap indexes for join processing: an implicit partitioning of the attributes, space-efficiency, and tolerance of high-cardinality relations.

  8. Join Order Selection - Good Enough is Easy

    NARCIS (Netherlands)

    Waas, F.; Pellenkoft, A.J.

    2000-01-01

    Uniform sampling of join orders is known to be a competitive alternative to transformation-based optimization techniques. However, uniformity of the sampling process is difficult to establish and only for a restricted class of join queries techniques are known. In this paper, we investigate non-un

  9. Innovative Structural and Joining Concepts for Lightweight Design of Heavy Vehicle Systems

    Energy Technology Data Exchange (ETDEWEB)

    Prucz, Jacky C; Shoukry, Samir N; William, Gergis W; Evans, Thomas H

    2006-09-30

    The extensive research and development effort was initiated by the U.S. Department of Energy (DOE) in 2002 at West Virginia University (WVU) in order to investigate practical ways of reducing the structural weight and increasing the durability of heavy vehicles through the judicious use of lightweight composite materials. While this project was initially focused on specific Metal Matrix Composite (MMC) material, namely Aluminum/Silicon Carbide (Al/SiC) commercially referenced as ''LANXIDE'', the current research effort was expanded from the component level to the system level and from MMC to other composite material systems. Broadening the scope of this research is warranted not only by the structural and economical deficiencies of the ''LANXIDE'' MMC material, but also by the strong coupling that exists between the material and the geometric characteristics of the structure. Such coupling requires a truly integrated design approach, focused on the heaviest sections of a van trailer. Obviously, the lightweight design methods developed in this study will not be implemented by the commercial industry unless the weight savings are indeed impressive and proven to be economically beneficial in the context of Life Cycle Costs (LCC). ''Bulk Haul'' carriers run their vehicles at maximum certified weight, so that each pound saved in structural weight would translate into additional pound of cargo, and fewer vehicles necessary to transport a given amount of freight. It is reasonable to ascertain that a typical operator would be ready to pay a premium of about $3-4 for every additional pound of cargo, or every pound saved in structural weight. The overall scope of this project is to devise innovative, lightweight design and joining concepts for heavy vehicle structures, including cost effective applications of components made of metal matrix composite (MMC) and other composite materials in selected sections of such

  10. Authenticated join processing in outsourced databases

    KAUST Repository

    Yang, Yin

    2009-01-01

    Database outsourcing requires that a query server constructs a proof of result correctness, which can be verified by the client using the data owner\\'s signature. Previous authentication techniques deal with range queries on a single relation using an authenticated data structure (ADS). On the other hand, authenticated join processing is inherently more complex than ranges since only the base relations (but not their combination) are signed by the owner. In this paper, we present three novel join algorithms depending on the ADS availability: (i) Authenticated Indexed Sort Merge Join (AISM), which utilizes a single ADS on the join attribute, (ii) Authenticated Index Merge Join (AIM) that requires an ADS (on the join attribute) for both relations, and (iii) Authenticated Sort Merge Join (ASM), which does not rely on any ADS. We experimentally demonstrate that the proposed methods outperform two benchmark algorithms, often by several orders of magnitude, on all performance metrics, and effectively shift the workload to the outsourcing service. Finally, we extend our techniques to complex queries that combine multi-way joins with selections and projections. ©2009 ACM.

  11. Stock vs. Bond Yields, and Demographic Fluctuations

    DEFF Research Database (Denmark)

    Gozluklu, Arie; Morin, Annaïg

    that the slow-evolving time-series covariation due to changing population age structure accounts for the equilibrium relation between stock and bond markets. As a result, by exploiting the demographic information into distant future, the forecasting performance of evaluation models improves. Finally, using...... a cross-country panel, we document the cross-sectional variation of the demographic effect and explain the cross-country differences in comovement between stock and bond markets.......This paper analyzes the strong comovement between real stock and nominal bond yields at generational (low) frequencies. Life-cycle patterns in savings behavior in an overlapping generations model with cash-in-advance constraints explain this persistent comovement between financial yields. We argue...

  12. Deformation and Failure of Polymer Bonded Explosives

    Institute of Scientific and Technical Information of China (English)

    陈鹏万; 黄风雷; 丁雁生

    2004-01-01

    The deformation and failure of pressed polymer bonded explosives under different types of loads including tension, compression and low velocity impact are presented. Brazilian test is used to study the tensile properties. The microstructure of polymer bonded explosives and its evolution are studied by use of scanning electronic microscopy and polarized light microscopy. Polishing techniques have been developed to prepare samples for microscopic examination. The failure mechanisms of polymer bonded explosives under different loads are analyzed. The results show that interfacial debonding is the predominant failure mode in quasi-static tension, while extensive crystal fractures are induced in compression. With the increase of strain rate, more crystal fractures occur. Low velocity impact also induces extensive crystal fractures.

  13. Microtensile Bond Strength of Single Bond and Adper Prompt-L-Pop Adhesives to Dentin

    Directory of Open Access Journals (Sweden)

    P. Alizadeh Oskoee

    2008-03-01

    Full Text Available Objective: The aim of this study was to evaluate the microtensile bond strength to sound and caries-affected dentin using Single Bond and Adper Prompt-L-Pop adhesives.Materials and Methods: Sixteen extracted human molars with carious lesions extended halfway through dentin were ground to expose the caries affected and the surrounding normal dentin. The samples were divided into two groups of eight samples each, including Single Bond (two-step etch and rinse and Adper Prompt-L-Pop (one step self-etch. Z-100 (3M was used for composite build-ups. The teeth were then sectioned and prepared for micro tensile bond strength test, at cross head speed of 1.5 mm/min. Data were ana-lyzed by 1- and 2-way ANOVA.Results: Bond strengths of Single Bond and Adper Prompt-L-Pop adhesives to sound den-tin were significantly higher than to the caries-affected one (P<0.001, besides, bond strength of Single Bond to dentin was generally found to be higher than Adper Prompt-L-Pop adhesive (P<0.001.The interaction effect was not significant (P=0.116Conclusion: Bond strength to caries-affected dentin was compromised when one and two step adhesives were used.

  14. Feasibility of ceramic joining with high energy electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Turman, B.N.; Glass, S.J.; Halbleib, J.A.; Helmich, D.R.; Loehman, R.E. [Sandia National Labs., Albuquerque, NM (United States); Clifford, J.R. [Titan Corp., Albuquerque, NM (United States)

    1995-01-01

    Joining structural ceramics is possible using high melting point metals such as Mo and Pt that are heated with a high energy electron beam, with the potential for producing joints with high temperature capability. A 10 MeV electron beam can penetrate through 1 cm of ceramic, offering the possibility of buried interface joining. Because of transient heating and the lower heat capacity of the metal relative to the ceramic, a pulsed high power beam has the potential for melting the metal without decomposing or melting the adjacent ceramic. The authors have demonstrated the feasibility of the process with a series of 10 MeV, 1 kW electron beam experiments. Shear strengths up to 28 NTa have been measured for Si{sub 3}N{sub 4}-Mo-Si{sub 3}N{sub 4}. These modest strengths are due to beam non-uniformity and the limited area of bonding. The bonding mechanism appears to be a thin silicide reaction layer. Si{sub 3}N{sub 4}-Si{sub 3}N{sub 4} joints with no metal layer were also produced, apparently bonded an yttrium apatite grain boundary phase.

  15. Symmetry in bonding and spectra an introduction

    CERN Document Server

    Douglas, Bodie E

    1985-01-01

    Many courses dealing with the material in this text are called ""Applications of Group Theory."" Emphasizing the central role and primary importance of symmetry in the applications, Symmetry in Bonding and Spectra enables students to handle applications, particularly applications to chemical bonding and spectroscopy. It contains the essential background in vectors and matrices for the applications, along with concise reviews of simple molecular orbital theory, ligand field theory, and treatments of molecular shapes, as well as some quantum mechanics. Solved examples in the text illustra

  16. Process Of Bonding Copper And Tungsten

    Science.gov (United States)

    Slattery, Kevin T.; Driemeyer, Daniel E.

    1999-11-23

    Process for bonding a copper substrate to a tungsten substrate by providing a thin metallic adhesion promoting film bonded to a tungsten substrate and a functionally graded material (FGM) interlayer bonding the thin metallic adhesion promoting film to the copper substrate. The FGM interlayer is formed by thermal plasma spraying mixtures of copper powder and tungsten powder in a varied blending ratio such that the blending ratio of the copper powder and the tungsten powder that is fed to a plasma torch is intermittently adjusted to provide progressively higher copper content/tungsten content, by volume, ratio values in the interlayer in a lineal direction extending from the tungsten substrate towards the copper substrate. The resulting copper to tungsten joint well accommodates the difference in the coefficient of thermal expansion of the materials.

  17. INTEREST RATES AND CURRENCIES EFFECTS ON ISLAMIC AND CONVENTIONAL BONDS

    Directory of Open Access Journals (Sweden)

    Ghazali Syamni

    2011-09-01

    Full Text Available Bond markets have not been well developed in emerging countries. Realizing its important role, especially after the 1997 crises and the islamic economics development, emerging countries have started to develop such markets. This research examines the effect of interest rates and currencies on Islamic and conventional bonds in Bursa Malaysia. The analysis on Islamic bonds shows that interest rates and currencies do not influence Islamic bonds, which supports the prohibition of interest in Islam. The analysis on conventional bonds finds evidence that both interest rates and currencies affect conventional bond. It also finds evidence of a negative association between interest rates and a conventional bond. Keywords: Interest rate, currency, conventional bond, Islamic bond JEL classification numbers: G11, G12, G15

  18. Design and Analysis of HIP joined W and Ferritic-Martensitic Steel Mockup for Fusion Reactor Divertor Development

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D. W.; Shin, K. I.; Kim, S. K.; Jin, H. G.; Lee, E. H.; Yoon, J. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Moon, S. Y.; Hong, B. G. [Chonbuk National Univ., Jeonju (Korea, Republic of)

    2013-10-15

    Korea has developed a Helium Cooled Ceramic Reflector (HCCR) based Test Blanket System (TBS) for an ITER, which consists of the First Wall (FW), Breeding Zone (BZ), Side Wall (SW), and BZ box. Among them, the FW is an important component which faces the plasma directly and, therefore, it is subjected to high heat and neutron loads. The FW of the TBM is considered to be composed of a beryllium (Be) armor as a plasma-facing material and Ferritic-Martensitic (FM) steel as a structure material, or a tungsten (W) armor and FM steel, or bare FM steel. Since Be/FMS and bare FMS were developed and proved by high heat flux (HHF) test, W armor and FM steel joining, fabricated mock-ups, and preparation of the high heat flux (HHF) test for integrity investigation are introduced in the present study. For the application to fusion reactor, joining methods with W to FMS has been developed. The W mock-up was fabricated with HIP considering Ti interlayer and PHHT condition. And the HHF test was prepared by performing the preliminary analysis to determine the test conditions. From the analysis heating and cooling conditions were determined for 0.5 and 1.0 MW/m2 heat fluxes. In the near future, the thermal life-time will be evaluated to determine the test period of the mockups by the mechanical analysis with ANSYS.

  19. The pnicogen bond: its relation to hydrogen, halogen, and other noncovalent bonds.

    Science.gov (United States)

    Scheiner, Steve

    2013-02-19

    Among a wide range of noncovalent interactions, hydrogen (H) bonds are well known for their specific roles in various chemical and biological phenomena. When describing conventional hydrogen bonding, researchers use the notation AH···D (where A refers to the electron acceptor and D to the donor). However, the AH molecule engaged in a AH···D H-bond can also be pivoted around by roughly 180°, resulting in a HA···D arrangement. Even without the H atom in a bridging position, this arrangement can be attractive, as explained in this Account. The electron density donated by D transfers into a AH σ* antibonding orbital in either case: the lobe of the σ* orbital near the H atom in the H-bonding AH···D geometry, or the lobe proximate to the A atom in the HA···D case. A favorable electrostatic interaction energy between the two molecules supplements this charge transfer. When A belongs to the pnictide family of elements, which include phosphorus, arsenic, antimony, and bismuth, this type of interaction is called a pnicogen bond. This bonding interaction is somewhat analogous to the chalcogen and halogen bonds that arise when A is an element in group 16 or 17, respectively, of the periodic table. Electronegative substitutions, such as a F for a H atom opposite the electron donor atom, strengthen the pnicogen bond. For example, the binding energy in FH(2)P···NH(3) greatly exceeds that of the paradigmatic H-bonding water dimer. Surprisingly, di- or tri-halogenation does not produce any additional stabilization, in marked contrast to H-bonds. Chalcogen and halogen bonds show similar strength to the pnicogen bond for a given electron-withdrawing substituent. This insensitivity to the electron-acceptor atom distinguishes these interactions from H-bonds, in which energy depends strongly upon the identity of the proton-donor atom. As with H-bonds, pnicogen bonds can extract electron density from the lone pairs of atoms on the partner molecule, such as N, O, and

  20. The Influence of Carbon Nanotube and Roll Bonding Parameters on the Bond Strength of Al Sheets

    Science.gov (United States)

    Samadzadeh, Mahmoud; Toroghinejad, Mohammad Reza

    2014-05-01

    This study investigates the bond strength of aluminum sheets subjected to the roll bonding process in the presence of multiwall carbon nanotubes (MWCNTs). The effects of MWCNTs dispersion, thickness reduction, weight fraction of MWCNTs at the interface, and rolling temperature on the bond strength of the commercial pure aluminum sheets are studied. The peeling test is used to evaluate the bond strength of aluminum sheets. Optical microscopy and scanning electron microscopy are also used to evaluate the surface conditions of the peeled surfaces. Results indicate that, compared to the spread method, using the solution dispersion method to disperse MWCNTs reduces aluminum sheet's bond strength. Also, the presence of MWCNTs reduces the sheet's bond strength compared to aluminum sheets at a constant thickness reduction. However, bond strength is increased with higher thickness reductions in the presence or absence of MWCNTs. It is also shown that increasing the entry temperature improves bond strength, but that bond strength enhancement is lower in aluminum-MWCNTs sheets than in aluminum-aluminum sheets.

  1. Effect of panel alignment and surface finish on bond strength

    Energy Technology Data Exchange (ETDEWEB)

    Wouters, J.M.; Doe, P.J. [Los Alamos National Lab., NM (United States); Baker, W.E. [New Mexico Univ., Albuquerque, NM (United States)

    1991-10-01

    The flexural strength of bonded acrylic is tested as a function of panel alignment and bond surface finish. Bond strength was shown to be highly dependent on both parameters with only a narrow range of values yielding a high strength bond. This study was performed for the heavy water-containing acrylic vessel for the Sudbury Neutrino Observatory detector.

  2. FE modeling of Cu wire bond process and reliability

    NARCIS (Netherlands)

    Yuan, C.A.; Weltevreden, E.R.; Akker, P. van den; Kregting, R.; Vreugd, J. de; Zhang, G.Q.

    2011-01-01

    Copper based wire bonding technology is widely accepted by electronic packaging industry due to the world-wide cost reduction actions (compared to gold wire bond). However, the mechanical characterization of copper wire differs from the gold wire; hence the new wire bond process setting and new bond

  3. Hybrid layer difference between sixth and seventh generation bonding agent

    Directory of Open Access Journals (Sweden)

    Grace Syavira Suryabrata

    2006-03-01

    Full Text Available Since etching is completed at the same stage as priming and bonding, when applying the sixth and seventh generation bonding, the exposed smear layers are constantly surrounded by primer and bonding and cannot collapse. The smear layer and the depth of penetration of resin bonding in dentinal tubules are completely integrated into hybrid layer. The purpose of this laboratory research was to study the penetration depth of two self etching adhesive. Fourteen samples of human extracted teeth were divided into two groups. Each groups consisted of seven samples, each of them was treated with sixth generation bonding agent and the other was treated with seventh generation bonding agent. The results disclosed that the penetration into dentinal tubules of seventh generation bonding agent was deeper than sixth generation bonding agent. Conclusion: bond strength will improve due to the increasing of penetration depth of resin bonding in dentinal tubules.

  4. METHOD AND ALLOY FOR BONDING TO ZIRCONIUM

    Science.gov (United States)

    McCuaig, F.D.; Misch, R.D.

    1960-04-19

    A brazing alloy can be used for bonding zirconium and its alloys to other metals, ceramics, and cermets, and consists of 6 to 9 wt.% Ni, 6 to 9 wn~.% Cr, Mo, or W, 0 to 7.5 wt.% Fe, and the balance Zr.

  5. Bond-length distributions for ions bonded to oxygen: alkali and alkaline-earth metals.

    Science.gov (United States)

    Gagné, Olivier Charles; Hawthorne, Frank Christopher

    2016-08-01

    Bond-length distributions have been examined for 55 configurations of alkali-metal ions and 29 configurations of alkaline-earth-metal ions bonded to oxygen, for 4859 coordination polyhedra and 38 594 bond distances (alkali metals), and for 3038 coordination polyhedra and 24 487 bond distances (alkaline-earth metals). Bond lengths generally show a positively skewed Gaussian distribution that originates from the variation in Born repulsion and Coulomb attraction as a function of interatomic distance. The skewness and kurtosis of these distributions generally decrease with increasing coordination number of the central cation, a result of decreasing Born repulsion with increasing coordination number. We confirm the following minimum coordination numbers: ([3])Li(+), ([3])Na(+), ([4])K(+), ([4])Rb(+), ([6])Cs(+), ([3])Be(2+), ([4])Mg(2+), ([6])Ca(2+), ([6])Sr(2+) and ([6])Ba(2+), but note that some reported examples are the result of extensive dynamic and/or positional short-range disorder and are not ordered arrangements. Some distributions of bond lengths are distinctly multi-modal. This is commonly due to the occurrence of large numbers of structure refinements of a particular structure type in which a particular cation is always present, leading to an over-representation of a specific range of bond lengths. Outliers in the distributions of mean bond lengths are often associated with anomalous values of atomic displacement of the constituent cations and/or anions. For a sample of ([6])Na(+), the ratio Ueq(Na)/Ueq(bonded anions) is partially correlated with 〈([6])Na(+)-O(2-)〉 (R(2) = 0.57), suggesting that the mean bond length is correlated with vibrational/displacement characteristics of the constituent ions for a fixed coordination number. Mean bond lengths also show a weak correlation with bond-length distortion from the mean value in general, although some coordination numbers show the widest variation in mean bond length for zero distortion, e.g. Li(+) in

  6. Human RECQ1 interacts with Ku70/80 and modulates DNA end-joining of double-strand breaks.

    Directory of Open Access Journals (Sweden)

    Swetha Parvathaneni

    Full Text Available Genomic instability is a known precursor to cancer and aging. The RecQ helicases are a highly conserved family of DNA-unwinding enzymes that play key roles in maintaining genome stability in all living organisms. Human RecQ homologs include RECQ1, BLM, WRN, RECQ4, and RECQ5β, three of which have been linked to diseases with elevated risk of cancer and growth defects (Bloom Syndrome and Rothmund-Thomson Syndrome or premature aging (Werner Syndrome. RECQ1, the first RecQ helicase discovered and the most abundant in human cells, is the least well understood of the five human RecQ homologs. We have previously described that knockout of RECQ1 in mice or knockdown of its expression in human cells results in elevated frequency of spontaneous sister chromatid exchanges, chromosomal instability, increased load of DNA damage and heightened sensitivity to ionizing radiation. We have now obtained evidence implicating RECQ1 in the nonhomologous end-joining pathway of DNA double-strand break repair. We show that RECQ1 interacts directly with the Ku70/80 subunit of the DNA-PK complex, and depletion of RECQ1 results in reduced end-joining in cell free extracts. In vitro, RECQ1 binds and unwinds the Ku70/80-bound partial duplex DNA substrate efficiently. Linear DNA is co-bound by RECQ1 and Ku70/80, and DNA binding by Ku70/80 is modulated by RECQ1. Collectively, these results provide the first evidence for an interaction of RECQ1 with Ku70/80 and a role of the human RecQ helicase in double-strand break repair through nonhomologous end-joining.

  7. Modeling, simulation and control of pulsed DE-GMA welding process for joining of aluminum to steel

    Science.gov (United States)

    Zhang, Gang; Shi, Yu; Li, Jie; Huang, Jiankang; Fan, Ding

    2014-09-01

    Joining of aluminum to steel has attracted significant attention from the welding research community, automotive and rail transportation industries. Many current welding methods have been developed and applied, however, they can not precisely control the heat input to work-piece, they are high costs, low efficiency and consist lots of complex welding devices, and the generated intermetallic compound layer in weld bead interface is thicker. A novel pulsed double electrode gas metal arc welding(Pulsed DE-GMAW) method is developed. To achieve a stable welding process for joining of aluminum to steel, a mathematical model of coupled arc is established, and a new control scheme that uses the average feedback arc voltage of main loop to adjust the wire feed speed to control coupled arc length is proposed and developed. Then, the impulse control simulation of coupled arc length, wire feed speed and wire extension is conducted to demonstrate the mathematical model and predict the stability of welding process by changing the distance of contact tip to work-piece(CTWD). To prove the proposed PSO based PID control scheme's feasibility, the rapid prototyping experimental system is setup and the bead-on-plate control experiments are conducted to join aluminum to steel. The impulse control simulation shows that the established model can accurately represent the variation of coupled arc length, wire feed speed and the average main arc voltage when the welding process is disturbed, and the developed controller has a faster response and adjustment, only runs about 0.1 s. The captured electric signals show the main arc voltage gradually closes to the supposed arc voltage by adjusting the wire feed speed in 0.8 s. The obtained typical current waveform demonstrates that the main current can be reduced by controlling the bypass current under maintaining a relative large total current. The control experiment proves the accuracy of proposed model and feasibility of new control scheme

  8. Modeling, Simulation and Control of Pulsed DE-GMA Welding Process for Joining of Aluminum to Steel

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gang; SHI Yu; LI Jie; HUANG Jiankang; FAN Ding

    2014-01-01

    Joining of aluminum to steel has attracted significant attention from the welding research community, automotive and rail transportation industries. Many current welding methods have been developed and applied, however, they can not precisely control the heat input to work-piece, they are high costs, low efficiency and consist lots of complex welding devices, and the generated intermetallic compound layer in weld bead interface is thicker. A novel pulsed double electrode gas metal arc welding(Pulsed DE-GMAW) method is developed. To achieve a stable welding process for joining of aluminum to steel, a mathematical model of coupled arc is established, and a new control scheme that uses the average feedback arc voltage of main loop to adjust the wire feed speed to control coupled arc length is proposed and developed. Then, the impulse control simulation of coupled arc length, wire feed speed and wire extension is conducted to demonstrate the mathematical model and predict the stability of welding process by changing the distance of contact tip to work-piece(CTWD). To prove the proposed PSO based PID control scheme’s feasibility, the rapid prototyping experimental system is setup and the bead-on-plate control experiments are conducted to join aluminum to steel. The impulse control simulation shows that the established model can accurately represent the variation of coupled arc length, wire feed speed and the average main arc voltage when the welding process is disturbed, and the developed controller has a faster response and adjustment, only runs about 0.1 s. The captured electric signals show the main arc voltage gradually closes to the supposed arc voltage by adjusting the wire feed speed in 0.8 s. The obtained typical current waveform demonstrates that the main current can be reduced by controlling the bypass current under maintaining a relative large total current. The control experiment proves the accuracy of proposed model and feasibility of new control scheme

  9. Summary of Dissimilar Metal Joining Trials Conducted by Edison Welding Institute

    Energy Technology Data Exchange (ETDEWEB)

    MJ Lambert

    2005-11-18

    noticeable reaction layer. T-111 was found to have a small reaction layer at the interface with deposited Hastelloy X. Mar M-247 had a reaction layer larger than T-111. Hastelloy X joined well with a substrate of the same alloy, and throughout the experiments was found to have a density of {approx}99%, based on metallographic observations of porosity in the deposit. Of the three joining methods tested, inertial welding of bar stock appears to be the most mature at this time. MPW may be an attractive alternative due to the potential for high bond integrity, similar to that seen in explosion bonding. However, all three joining methods used in this work will require adaptation in order to join piping and tubing. Further investigations into the change in mechanical properties of these joints with time, temperature, irradiation, and the use of interlayers between the two materials must also be performed.

  10. Hole-pin joining structure with fiber-round-hole distribution of lobster cuticle and biomimetic study.

    Science.gov (United States)

    Chen, Bin; Fan, Jinghong; Gou, Jihua; Lin, Shiyun

    2014-12-01

    Observations of the cuticle of the Boston Spiny Lobster using scanning electron microscope (SEM) show that it is a natural biocomposite consisting of chitin fibers and sclerotic-protein matrix with hierarchical and helicoidal structure. The SEM images also indicate that there is a hole-pin joining structure in the cuticle. In this joining structure, the chitin fibers in the neighborhood of the joining holes continuously round the holes to form a fiber-round-hole distribution. The maximum pullout force of the fibers in the fiber-round-hole distribution, which is closely related to the fracture toughness of the cuticle, is investigated and compared with that of the fibers in non-fiber-round-hole distribution based on their representative models. It is revealed that the maximum pullout force of the fibers in the fiber-round-hole distribution is significantly larger than that of the fibers in the non-fiber-round-hole distribution, and that a larger diameter of the hole results in a larger difference in the maximum pullout forces of the fibers between the two kinds of the fiber distributions. Inspired by the fiber-round-hole distribution found in the cuticle, composite specimens with the fiber-round-hole distribution were fabricated with a special mold and process to mirror the fiber-round-hole distribution. The fracture toughness of the biomimetic composite specimens is tested and compared with that of the conventional composite specimens with the non-fiber-round-hole distribution. It is demonstrated that the fracture toughness of the biomimetic composite specimens with the fiber-round-hole distribution is significantly larger than that of the conventional composite specimens with the non-fiber-round-hole distribution.

  11. Joining of composite shafts and workpieces by rolling-in; Fuegen von gebauten Wellen und Verbundbauteilen durch Einwalzen

    Energy Technology Data Exchange (ETDEWEB)

    Hagedorn, M. [MHP Mannesmann Praezisrohr GmbH, Muelheim (Germany). Bereich Automobilindustrie; Kessler, N.; Weinert, K. [Dortmund Univ. (Germany). Inst. fuer Spanende Fertigung; Wilcke, G.; Roettger, K. [Ecoroll AG, Celle (Germany)

    2006-07-01

    The roller burnishing and deep rolling of drill holes or other profiles is a well established process for achieving a very high surface quality and for enhancing the fatigue strength significantly. With the development of the rolling-in process for manufacturing composite workpieces like e.g. composite shafts and camshafts the possible fields of application of the rolling process can be extended by an interesting aspect. For rolling0in specially adapted tools were used with a higher rolling oversize to join by expanding an inner component inside an outer part, both optimised for special requirements.

  12. SIGNIFICANCE AND CONTRIBUTION OF BONDS OF THE REPUBLIC OF SRPSKA

    OpenAIRE

    Vesna Bogičević

    2011-01-01

    In this paper, emphasis is placedon bonds that during 2009 and 2010 became anabsolute hit on the Banja Luka Stock Exchange.These are types of bonds whose issuer is theRepublic of Srpska, designated as bonds of wardamage and bonds for the payment of old foreigncurrency savings. The paper elaborates the reasonsfor issuing the bonds, due to their influence on thecapital market development in the Republic ofSrpska.

  13. Structural modeling and optimization of a joined-wing configuration of a High-Altitude Long-Endurance (HALE) aircraft

    Science.gov (United States)

    Kaloyanova, Valentina B.

    Recent research trends have indicated an interest in High-Altitude, Long-Endurance (HALE) aircraft as a low-cost alternative to certain space missions, such as telecommunication relay, environmental sensing and military reconnaissance. HALE missions require a light vehicle flying at low speed in the stratosphere at altitudes of 60,000-80,000 ft, with a continuous loiter time of up to several days. To provide high lift and low drag at these high altitudes, where the air density is low, the wing area should be increased, i.e., high-aspect-ratio wings are necessary. Due to its large span and lightweight, the wing structure is very flexible. To reduce the structural deformation, and increase the total lift in a long-spanned wing, a sensorcraft model with a joined-wing configuration, proposed by AFRL, is employed. The joined-wing encompasses a forward wing, which is swept back with a positive dihedral angle, and connected with an aft wing, which is swept forward. The joined-wing design combines structural strength, high aerodynamic performance and efficiency. As a first step to study the joined-wing structural behavior an 1-D approximation model is developed. The 1-D approximation is a simple structural model created using ANSYS BEAM4 elements to present a possible approach for the aerodynamics-structure coupling. The pressure loads from the aerodynamic analysis are integrated numerically to obtain the resultant aerodynamic forces and moments (spanwise lift and pitching moment distributions, acting at the aerodynamic center). These are applied on the 1-D structural model. A linear static analysis is performed under this equivalent load, and the deformed shape of the 1-D model is used to obtain the deformed shape of the actual 3-D joined wing, i.e. deformed aerodynamic surface grid. To date in the existing studies, only simplified structural models have been examined. In the present work, in addition to the simple 1-D beam model, a semi-monocoque structural model is

  14. Numerical Modelling and Experimental Investigation of Microsegregation in Al-4.45 wt pct Cu: Effect of Dendrite Joining

    Institute of Scientific and Technical Information of China (English)

    H.B.Dong

    2005-01-01

    A numerical model Alloy/M has been applied to investigate the microsegregation in Al-4.45 wt pct Cu alloy. The calculated data were compared with the experimental measurements for samples solidified at different cooling rates.Discrepancies in solute concentration occur between the experimental observations and calculated results. Reasons for the discrepancies were discussed, and the effect of dendrite joining at a later stage of solidification on the microsegregation was investigated. Calculations that have included this effect showed a better fit with experimental results.

  15. Stress relaxation and bonding in Si3N4/MA6000 joints by reactive interlayers

    Science.gov (United States)

    Frisch, A.; Kaysser, W. A.; Zhang, W.; Petzow, G.

    Diffusion bonding of Si3N4 to the new generation of ODS-superalloys, such as MA6000, may yield strongly joined metal-ceramic systems for high-temperature applications. Si3N4 has been diffusion bonded to MA6000 during HIP at 100 MPa at 1100-1300 C. Stresses caused by the large thermal mismatch were reduced by multiphase interlayers. To promote the chemical adhesion, reactive and adhesive interlayers were used at the metal-ceramic interface which, in the absence of such layers, fail at low stresses. It has been shown that, during reactive bonding, brittle phases are frequently formed at the interfaces which may lead to a failure of the joint. The reduce of thermal stresses by thin soft interlayers is very limited but can be obtained by a microcrack-induced stress relaxation mechanism. During adhesive diffusion bonding, the mechanical strength of the bond is limited by the stress state and the strength of the ceramic component.

  16. New gravitational formula as a bridge to join the modern physics and the classical physics

    Science.gov (United States)

    Chen, Shao-Guang

    measuring value of one-way velocity of light (H05-0020-08) to replace the infinity value of light speed measured by Galileo in 1607, thereby the mass m in NM will become variable m. Or else, the energy of electron in accelerator should not larger than 0.51Mev which conflict with the experimental fact. According to the variable mass and the definition of force we again get Eq.(1) from NM without hypothesis, i.e., NM is generalized in which Galileo coordinates transformation and the action at a distance will be of no effect. Eq.(1) has more reliable experimental base and generalized NM may be applied to the high-speed and the microscopic conditions. Because of the result of a test of GR with use of a hydrogen-maser frequency standard in a spacecraft launched nearly vertically upward to 10000 km (R. F. C. Vessot et.al., Phys. Rev. Lett. 45, 2081 (1980)), the isotropy of one-way velocity of light had been validated at the 1*10 (-10) level (D2.4-0030-12, H0.1-0009-12, H0.2-0008-12). Again from the Lorentz transformation (H01-0006-08) and the uncertainty principle (H05-0036-10) deduced from the metrical results of Doppler effects, SR and QM, thereby QFT and GR, all become the inferential theorems from generalized NM. Formula (1) is as a bridge to join the modern physics and classical physics. The inertial system (IS) is defined as a linear coordinate system with equal speed, for to judge it yes or not IS we again must measure in a linear coordinate system with equal speed. At the acceleration coordinate to judge IS will make a mistake. So that IS in a logic cycle with self to judge itself. In other words, to determine an IS need another IS, how to judge the first IS? In present measuring precision, we would not find a real IS, Galileo ship concept became as history. The definition of IS in NM had been inherited by SR, GR, QM and QFT, in GR the IS become the local IS. The logic cycle of IS will be a collective problem of the modern physics and the classical physics, and leads to

  17. Composite bonding to stainless steel crowns using a new universal bonding and single-bottle systems.

    Science.gov (United States)

    Hattan, Mohammad Ali; Pani, Sharat Chandra; Alomari, Mohammad

    2013-01-01

    Aim. The aim of this study is to evaluate the shear bond strength of nanocomposite to stainless steel crowns using a new universal bonding system. Material and Methods. Eighty (80) stainless steel crowns (SSCs) were divided into four groups (20 each). Packable nanocomposite was bonded to the lingual surface of the crowns in the following methods: Group A without adhesive (control group), Group B using a new universal adhesive system (Scotchbond Universal Adhesive, 3M ESPE, Seefeld, Germany), and Group C and Group D using two different brands of single-bottle adhesive systems. Shear bond strengths were calculated and the types of failure also were recorded. Results. The shear strength of Group B was significantly greater than that of other groups. No significant differences were found between the shear bond strengths of Groups C and D. The control group had significantly lower shear bond strength (P steel crowns using the new universal bonding agent (Scotchbond Universal Adhesive, 3M ESPE, Seefeld, Germany) show significantly greater shear bond strengths and fewer adhesive failures when compared to traditional single-bottle systems.

  18. Joining technology for parts for plastic and thin sheet metal parts; Fuegetechniken fuer Bauteile aus Kunststoff und duennwandigem Metall

    Energy Technology Data Exchange (ETDEWEB)

    Ahlers-Hestermann, G. [BOELLHOFF, Bielefeld (Germany)

    2001-07-01

    With the ongoing application of new materials (Al, Mg, Plastic) as an alternative to steel in light-weight body in white construction it is necessary to develop and use other joining and fixing technologies than spot welding, bolt-and nut-welding. These new technologies for example are mechanical joining technology as clinching and self-pierce-riveting, blind-riveting and special elements to fix other parts as blind-rivets and self-piercing nuts and bolts. These products are mainly used for metal materials and mixed structures. To fix other parts to plastic-parts direct-screwing or the after-moulding-technology with metal or plastic inserts is used. (orig.) [German] Mit der verstaerkten Anwendung von weiteren Werkstoffen (Al, Mg, Kunststoffe) als Stahl im Automobilbau ist die Notwendigkeit erwachsen, alternative Fuege- und Befestigungstechniken zum Punktschweissen, Bolzen- und Mutternschweissen zu entwickeln. Hierzu gehoeren die mechanischen Fuegetechniken wie Stanznieten, Clinchen, Blindnieten sowie die sogenannten Funktionselemente zum Befestigen von Anbauteilen, wie Blind- und Stanznietmuttern und -bolzen. Diese Verfahren werden ueberwiegend fuer metallische Werkstoffe oder bei Mischbauweise angewandt. Fuer die Befestigung an Kunststoffbauteilen wird die Direktverschraubung oder die after-moulding-technik (AMTEC {sup registered}) verwendet. (orig.)

  19. Synthesis and characterization of Ni-Mo filler brazing alloy for Mo-W joining for microwave tube technology

    Directory of Open Access Journals (Sweden)

    Frank Ferrer Sene

    2013-04-01

    Full Text Available A brazing process based on Ni-Mo alloy was developed to join porous tungsten cathode bottom and dense molybdenum cathode body for microwave tubes manufacture. The Ni-Mo alloy was obtained by mixing and milling powders in the eutectic composition, and applied on the surface of the components. The brazing was made at 1400 °C by using induction heating in hydrogen for 5 minutes. Alumina surfaces were coated with the binder and analyzed by Energy Dispersive X-rays Fluorescence. The brazed samples were analyzed by Scanning Electron Microscopy coupled to Energy Dispersive Spectroscopy. Stress-strain tests were performed to determine the mechanical behavior of the joining. The quality of the brazing was evaluated by assuring the presence of a "meniscus" formed by the Ni-Mo alloy on the border of the tungsten and molybdenum joint, the absence of microstructural defects in the interface between the tungsten and molybdenum alloys, and the adhesion of the brazed components.

  20. Redundant function of DNA ligase 1 and 3 in alternative end-joining during immunoglobulin class switch recombination.

    Science.gov (United States)

    Masani, Shahnaz; Han, Li; Meek, Katheryn; Yu, Kefei

    2016-02-02

    Nonhomologous end-joining (NHEJ) is the major DNA double-strand break (DSB) repair pathway in mammals and resolves the DSBs generated during both V(D)J recombination in developing lymphocytes and class switch recombination (CSR) in antigen-stimulated B cells. In contrast to the absolute requirement for NHEJ to resolve DSBs associated with V(D)J recombination, DSBs associated with CSR can be resolved in NHEJ-deficient cells (albeit at a reduced level) by a poorly defined alternative end-joining (A-EJ) pathway. Deletion of DNA ligase IV (Lig4), a core component of the NHEJ pathway, reduces CSR efficiency in a mouse B-cell line capable of robust cytokine-stimulated CSR in cell culture. Here, we report that CSR levels are not further reduced by deletion of either of the two remaining DNA ligases (Lig1 and nuclear Lig3) in Lig4(-/-) cells. We conclude that in the absence of Lig4, Lig1, and Lig3 function in a redundant manner in resolving switch region DSBs during CSR.

  1. A review of joining techniques for SiC{sub f}/SiC composites for first wall applications

    Energy Technology Data Exchange (ETDEWEB)

    Lewinsohn, C.A.; Jones, R.H. [Pacific Northwest National Lab., Richland, WA (United States)

    1998-09-01

    Many methods for joining monolithic and composite silicon carbide are available. Three techniques are candidates for use in fusion energy systems: in-situ displacement reactions, pre-ceramic polymer adhesives, and reaction bonding. None of the methods are currently developed enough to satisfy all of the criteria required, i.e., low temperature fabrication, high strength, and radiation stability. 58 refs.

  2. A Join Index for XML Data Warehouses

    CERN Document Server

    Mahboubi, Hadj; Darmont, Jérôme

    2008-01-01

    XML data warehouses form an interesting basis for decision-support applications that exploit complex data. However, native-XML database management systems (DBMSs) currently bear limited performances and it is necessary to research for ways to optimize them. In this paper, we propose a new join index that is specifically adapted to the multidimensional architecture of XML warehouses. It eliminates join operations while preserving the information contained in the original warehouse. A theoretical study and experimental results demonstrate the efficiency of our join index. They also show that native XML DBMSs can compete with XML-compatible, relational DBMSs when warehousing and analyzing XML data.

  3. Microwave joining of SiC

    Energy Technology Data Exchange (ETDEWEB)

    Silberglitt, R.; Ahmad, I.; Tian, Y.L. [FM Technologies, Inc., Fairfax, VA (United States)] [and others

    1997-04-01

    The purpose of this work is to optimize the properties of SiC-SiC joints made using microwave energy. The current focus is on identification of the most effective joining methods for scale-up to large tube assemblies, including joining using SiC produced in situ from chemical precursors. During FY 1996, a new microwave applicator was designed, fabricated and tested that provides the capability for vacuum baking of the specimens and insulation and for processing under inert environment. This applicator was used to join continuous fiber-reinforced (CFCC) SiC/SiC composites using a polymer precursor to form a SiC interlayer in situ.

  4. Optimizing joins between two partitioned relations in distributed databases

    Energy Technology Data Exchange (ETDEWEB)

    Ceri, S.; Gottlob, G.

    1986-06-01

    In this paper, the authors analyzed the optimization of joins between two partitioned relations in distributed databases. They discuss the ''semantic'' optimization of joins, semi-join reduction, and join optimization. Finally, they have presented an overall procedure for join optimization which uses semi-join reduction and join optimization as building blocks. Several results of this paper, such as the principles of semantic optimization and Proposition 1, are simple in nature but appear to be very important from an application viewpoint. The join optimization program presented in Section 5 can be realistically applied, because the authors introduced a simplification of the program which reduces the number of decision variables.

  5. DNA ligase III and DNA ligase IV carry out genetically distinct forms of end joining in human somatic cells.

    Science.gov (United States)

    Oh, Sehyun; Harvey, Adam; Zimbric, Jacob; Wang, Yongbao; Nguyen, Thanh; Jackson, Pauline J; Hendrickson, Eric A

    2014-09-01

    Ku-dependent C-NHEJ (classic non-homologous end joining) is the primary DNA EJing (end joining) repair pathway in mammals. Recently, an additional EJing repair pathway (A-NHEJ; alternative-NHEJ) has been described. Currently, the mechanism of A-NHEJ is obscure although a dependency on LIGIII (DNA ligase III) is often implicated. To test the requirement for LIGIII in A-NHEJ we constructed a LIGIII conditionally-null human cell line using gene targeting. Nuclear EJing activity appeared unaffected by a deficiency in LIGIII as, surprisingly, so were random gene targeting integration events. In contrast, LIGIII was required for mitochondrial function and this defined the gene's essential activity. Human Ku:LIGIII and Ku:LIGIV (DNA ligase IV) double knockout cell lines, however, demonstrated that LIGIII is required for the enhanced A-NHEJ activity that is observed in Ku-deficient cells. Most unexpectedly, however, the majority of EJing events remained LIGIV-dependent. In conclusion, although human LIGIII has an essential function in mitochondrial maintenance, it is dispensable for most types of nuclear DSB repair, except for the A-NHEJ events that are normally suppressed by Ku. Moreover, we describe that a robust Ku-independent, LIGIV-dependent repair pathway exists in human somatic cells.

  6. Microstructure and properties of hot roll bonding layer of dissimilar metals. 2. Bonding interface microstructure of Zr/stainless steel by hot roll bonding and its controlling

    Energy Technology Data Exchange (ETDEWEB)

    Yasuyama, Masanori; Ogawa, Kazuhiro; Taka, Takao; Nakasuji, Kazuyuki [Sumitomo Metal Industries Ltd., Osaka (Japan); Nakao, Yoshikuni; Nishimoto, Kazutoshi

    1996-07-01

    The hot roll bonding of zirconium and stainless steel inserted with tantalium was investigated using the newly developed rolling mill. The effect of hot rolling temperatures of zirconium/stainless steel joints on bonding interface structure was evaluated. Intermetallic compound layer containing cracks was observed at the bonding interface between stainless steel and tantalium when the rolling temperature was above 1373K. The hardness of the bonding layer of zirconium and tantalium bonded above 1273K was higher than tantalium or zirconium base metal in spite of absence of intermetallic compound. The growth of reaction layer at the stainless steel and tantalium interface and at the tantalium and zirconium interface was conforming a parabolic low when that was isothermally heated after hot roll bonding, and the growth rate was almost same as that of static diffusion bonding without using hot roll bonding process. It is estimated that the strain caused by hot roll bonding gives no effect on the growth of reaction layer. It was confirmed that the dissimilar joint of zirconium and stainless steel with insert of tantalium having the sound bonding interface were obtained at the suitable bonding temperature of 1173K by the usage of the newly developed hot roll bonding process. (author)

  7. Joining of silicon carbide using interlayer with matching coefficient of thermal expansion

    Energy Technology Data Exchange (ETDEWEB)

    Perham, T. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering]|[Lawrence Berkeley National Lab., CA (United States)

    1996-11-01

    The primary objective of this study is to develop a technique for joining a commercially available Silicon Carbide that gives good room temperature strength and the potential for good high temperature strength. One secondary objective is that the joining technique be adaptable to SiC{sub f}/SiC composites and/or Nickel based superalloys, and another secondary objective is that the materials provide good neutron irradiation resistance and low activation for potential application inside nuclear fusion reactors. The joining techniques studied here are: (1) reaction bonding with Al-Si/Si/SiC/C; (2) reaction/infiltration with calcium aluminum silicate; (3) ion exchange mechanism to form calcium hexaluminate (a refractory cement); and (4) oxide frit brazing with cordierite.

  8. Atomic bonding between metal and graphene

    KAUST Repository

    Wang, Hongtao

    2013-03-07

    To understand structural and chemical properties of metal-graphene composites, it is crucial to unveil the chemical bonding along the interface. We provide direct experimental evidence of atomic bonding between typical metal nano structures and graphene, agreeing well with density functional theory studies. Single Cr atoms are located in the valleys of a zigzag edge, and few-atom ensembles preferentially form atomic chains by self-assembly. Low migration barriers lead to rich dynamics of metal atoms and clusters under electron irradiation. We demonstrate no electron-instigated interaction between Cr clusters and pristine graphene, though Cr has been reported to be highly reactive to graphene. The metal-mediated etching is a dynamic effect between metal clusters and pre-existing defects. The resolved atomic configurations of typical nano metal structures on graphene offer insight into modeling and simulations on properties of metal-decorated graphene for both catalysis and future carbon-based electronics. © 2013 American Chemical Society.

  9. Thermochemistry and bond dissociation energies of ketones.

    Science.gov (United States)

    Hudzik, Jason M; Bozzelli, Joseph W

    2012-06-14

    Ketones are a major class of organic chemicals and solvents, which contribute to hydrocarbon sources in the atmosphere, and are important intermediates in the oxidation and combustion of hydrocarbons and biofuels. Their stability, thermochemical properties, and chemical kinetics are important to understanding their reaction paths and their role as intermediates in combustion processes and in atmospheric chemistry. In this study, enthalpies (ΔH°(f 298)), entropies (S°(T)), heat capacities (C(p)°(T)), and internal rotor potentials are reported for 2-butanone, 3-pentanone, 2-pentanone, 3-methyl-2-butanone, and 2-methyl-3-pentanone, and their radicals corresponding to loss of hydrogen atoms. A detailed evaluation of the carbon-hydrogen bond dissociation energies (C-H BDEs) is also performed for the parent ketones for the first time. Standard enthalpies of formation and bond energies are calculated at the B3LYP/6-31G(d,p), B3LYP/6-311G(2d,2p), CBS-QB3, and G3MP2B3 levels of theory using isodesmic reactions to minimize calculation errors. Structures, moments of inertia, vibrational frequencies, and internal rotor potentials are calculated at the B3LYP/6-31G(d,p) density functional level and are used to determine the entropies and heat capacities. The recommended ideal gas-phase ΔH°(f 298), from the average of the CBS-QB3 and G3MP2B3 levels of theory, as well as the calculated values for entropy and heat capacity are shown to compare well with the available experimental data for the parent ketones. Bond energies for primary, secondary, and tertiary radicals are determined; here, we find the C-H BDEs on carbons in the α position to the ketone group decrease significantly with increasing substitution on these α carbons. Group additivity and hydrogen-bond increment values for these ketone radicals are also determined.

  10. Joining NanoSIMS and STXM/NEXAFS to visualize soil biotic and abiotic processes at the nano-scale

    Science.gov (United States)

    Pett-Ridge, J.; Keiluweit, M.; Bougoure, J.; Weber, P. K.; Kleber, M.; Nico, P.

    2012-04-01

    Understanding the fate and residence time of organic matter in soils is important to natural resource management, including strategies to mitigate climate change. The time scales of carbon cycling, the relative importance of biotic and abiotic processes in organic matter stabilization in soils, and spatial factors in these processes are all critical characteristics that currently cannot be addressed by any single analytical approach. Here we demonstrate how many of these concerns can be approached by a combination of high-resolution secondary ion mass spectroscopy (NanoSIMS) and Scanning Transmission X-ray Microscopy (STXM) coupled with Near Edge X-ray Absorption Fine Structure spectroscopy (NEXAFS). When used in concert, these analytical techniques have the capacity to yield quantitative, in situ information on the source, molecular class, and elemental quantity of organic matter. We: (i) discuss the rationale for the joined application of the two procedures, (ii) provide examples for the their combined application, (iii) point out some of the methodological caveats that warrant consideration, and (iv) provide some directions for future developmental efforts. To illustrate the synergies of this combined approach, we examined organic-mineral associations in samples from both an artificial well-defined mixture and an unconstrained natural soil decomposition experiment. Case 1 demonstrates how the joined techniques help to determine modes of interaction between 13C- and 15N-labeled microorganisms and a defined mineral phase;, in case 2 we examine the incorporation of a 15N label into mineral organic associations 12 years after application to a forest soil. This unique analytical combination, the simultaneous application of STXM/NEXAFS and NanoSIMS imaging, has the potential to contribute a mechanistic understanding of sorption, occlusion, and decomposition processes that operate at fine spatial scales in natural environments.

  11. Effect of clearfil protect bond and transbond plus self-etch primer on shear bond strength of orthodontic brackets

    Directory of Open Access Journals (Sweden)

    S Hamid Raji

    2011-01-01

    Conclusion: The shear bond strength of clearfil protect bond and transbond plus self-etch primer was enough for bonding the orthodontic brackets. The mode of failure of bonded brackets with these two self-etch primers is safe for enamel.

  12. Why do people join trade unions?

    DEFF Research Database (Denmark)

    Toubøl, Jonas; Jensen, Carsten Strøby

    In this study the reasons for joining a trade union are analyzed statistically using high quality data from Statistics Denmark comprising the entire Danish workforce combined with European Social Survey data from rounds 1-3. These data enables measuring the effect of union density at the workplace...... to be a value rational motive. The statistical results indicate that the most important predictor of joining the union is workplace union density and only in a secondary manner does political attitude matter. It is concluded that the normative pressure of one’s colleagues is the dominating reason for joining...

  13. Why do people join trade unions?

    DEFF Research Database (Denmark)

    Toubøl, Jonas; Jensen, Carsten Strøby

    to be a value rational motive. The statistical results indicate that the most important predictor of joining the union is workplace union density and only in a secondary manner does political attitude matter. It is concluded that the normative pressure of one’s colleagues is the dominating reason for joining...... level on union recruitment, which is not done before. Workplace union density is taken to measure the strength of the workplace’s custom of being union member creating an instrumental incentive to join the union. Self-placement on a political left-right scale measures political attitude taken...

  14. Microtensile Bond Strength of Single Bond and Adper Prompt-L-Pop Adhesives to Dentin

    OpenAIRE

    P. Alizadeh Oskoee; AA. Ajami; S. Savadi Oskoee; F. Pournaghi-Azar

    2008-01-01

    Objective: The aim of this study was to evaluate the microtensile bond strength to sound and caries-affected dentin using Single Bond and Adper Prompt-L-Pop adhesives.Materials and Methods: Sixteen extracted human molars with carious lesions extended halfway through dentin were ground to expose the caries affected and the surrounding normal dentin. The samples were divided into two groups of eight samples each, including Single Bond (two-step etch and rinse) and Adper Prompt-L-Pop (one step s...

  15. Bond return predictability in expansions and recessions

    DEFF Research Database (Denmark)

    Engsted, Tom; Møller, Stig Vinther; Jensen, Magnus David Sander

    We document that over the period 1953-2011 US bond returns are predictable in expansionary periods but unpredictable during recessions. This result holds in both in-sample and out-of-sample analyses and using both univariate regressions and combination forecasting techniques. A simulation study...... shows that our tests have power to reject unpredictability in both expansions and recessions. To judge the economic significance of the results we compute utility gains for a meanvariance investor who takes the predictability patterns into account and show that utility gains are positive in expansions...... but negative in recessions. The results are also consistent with tests showing that the expectations hypothesis of the term structure holds in recessions but not in expansions. However, the results for bonds are in sharp contrast to results for stocks showing that stock returns are predictable in recessions...

  16. Unusual H-Bond Topology and Bifurcated H-bonds in the 2-Fluoroethanol Trimer.

    Science.gov (United States)

    Thomas, Javix; Liu, Xunchen; Jäger, Wolfgang; Xu, Yunjie

    2015-09-28

    By using a combination of rotational spectroscopy and ab initio calculations, an unusual H-bond topology was revealed for the 2-fluoroethanol trimer. The trimer exhibits a strong heterochiral preference and adopts an open OH⋅⋅⋅OH H-bond topology while utilizing two types of bifurcated H-bonds involving organic fluorine. This is in stark contrast to the cyclic OH⋅⋅⋅OH H-bond topology adopted by trimers of water and other simple alcohols. The strengths of different H-bonds in the trimer were analyzed by using the quantum theory of atoms in molecules. The study showcases a remarkable example of a chirality-induced switch in H-bond topology in a simple transient chiral fluoroalcohol. It provides important insight into the H-bond topologies of small fluoroalcohol aggregates, which are proposed to play a key role in protein folding and in enantioselective reactions and separations where fluoroalcohols serve as a (co)solvent.

  17. Expectations, Bond Yields and Monetary Policy

    DEFF Research Database (Denmark)

    Chun, Albert Lee

    2011-01-01

    expectations about inflation, output growth, and the anticipated path of monetary policy actions contain important information for explaining movements in bond yields. Estimates from a forward-looking monetary policy rule suggest that the central bank exhibits a preemptive response to inflationary expectations...... while accommodating output growth and monetary policy expectations. Forecasted GDP growth plays a significant role in explaining time variation in the market prices of risk. The sensitivity of long yields is linked to the persistence of expected inflation under the risk-neutral measure. Models...... of this type may provide traders and policymakers with a new set of tools for formally assessing the reaction of bond yields to shifts in market expectations...

  18. Homolytic Bond Dissociation Enthalpies of C C and C-H Bonds in Highly Crowded Alkanes

    Institute of Scientific and Technical Information of China (English)

    ZHU Chen; RUI Lei; FU Yao

    2008-01-01

    The homolytic C-C and C--H bond dissociation enthalpyies (BDE) of highly crowded alkanes were calcu- lated by using an ONIOM-G3B3 method. Geometric parameters such as bond length, bond angle and molecular volume were carefully investigated, as most of the acyclic alkanes in this study were not yet synthesized. These pa-rameters reflect the influence of steric effect on BDE. Good correlations were found between the rapid decrease of BDE and the increase of molecular volumes. The correlations can be applied to the prediction of the possible exis-tence of many highly strained compounds.

  19. Preliminary results for explosion bonding of beryllium to copper

    Energy Technology Data Exchange (ETDEWEB)

    Butler, D.J. [Northwest Technical Industries, Inc., Sequim, WA (United States); Dombrowski, D.E. [Brush Wellman, Inc., Cleveland, OH (United States)

    1995-09-01

    This program was undertaken to determine if explosive bonding is a viable technique for joining beryllium to copper substrates. The effort was a cursory attempt at trying to solve some of the problems associated with explosive bonding beryllium and should not be considered a comprehensive research effort. There are two issues that this program addressed. Can beryllium be explosive bonded to copper substrates and can the bonding take place without shattering the beryllium? Thirteen different explosive bonding iterations were completed using various thicknesses of beryllium that were manufactured with three different techniques.

  20. Microstructure of arc brazed and diffusion bonded joints of stainless steel and SiC reinforced aluminum matrix composite

    Science.gov (United States)

    Elßner, M.; Weis, S.; Grund, T.; Wagner, G.; Habisch, S.; Mayr, P.

    2016-03-01

    Joint interfaces of aluminum and stainless steel often exhibit intermetallics of Al-Fe, which limit the joint strength. In order to reduce these brittle phases in joints of aluminum matrix composites (AMC) and stainless steel, diffusion bonding and arc brazing are used. Due to the absence of a liquid phase, diffusion welding can reduce the formation of these critical in- termetallics. For this joining technique, the influence of surface treatments and adjusted time- temperature-surface-pressure-regimes is investigated. On the other hand, arc brazing offers the advantage to combine a localized heat input with the application of a low melting filler and was conducted using the system Al-Ag-Cu. Results of the joining tests using both approaches are described and discussed with regard to the microstructure of the joints and the interfaces.

  1. Optimization of Laser Transmission Joining Process Parameters on Joint Strength of PET and 316 L Stainless Steel Joint Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Shashi Prakash Dwivedi

    2014-01-01

    Full Text Available The objective of the present work is to study the effects of laser power, joining speed, and stand-off distance on the joint strength of PET and 316 L stainless steel joint. The process parameters were optimized using response methodology for achieving good joint strength. The central composite design (CCD has been utilized to plan the experiments and response surface methodology (RSM is employed to develop mathematical model between laser transmission joining parameters and desired response (joint strength. From the ANOVA (analysis of variance, it was concluded that laser power is contributing more and it is followed by joining speed and stand-off distance. In the range of process parameters, the result shows that laser power increases and joint strength increases. Whereas joining speed increases, joint strength increases. The joint strength increases with the increase of the stand-off distance until it reaches the center value; the joint strength then starts to decrease with the increase of stand-off distance beyond the center limit. Optimum values of laser power, joining speed, and stand-off distance were found to be 18 watt, 100 mm/min, and 2 mm to get the maximum joint strength (predicted: 88.48 MPa. There was approximately 3.37% error in the experimental and modeled results of joint strength.

  2. Exchange Rate Policy and Sovereign Bond Spreads in Developing Countries

    OpenAIRE

    2004-01-01

    We test the hypothesis of a link between exchange rate policy and sovereign bonds. We analyze the effect of exchange rate policies on supply and credit spreads of sovereign bonds issued by developing countries. An exchange rate policy is captured by the de facto exchange rate regime and the real exchange rate misalignment. The main findings are: (1) real exchange rate overvaluation significantly increases sovereign bond issue probability and raises bond spreads; (2) spreads and the likelihood...

  3. Prediction of allosteric sites and mediating interactions through bond-to-bond propensities

    CERN Document Server

    Amor, Benjamin R C; Yaliraki, Sophia N; Barahona, Mauricio

    2016-01-01

    Allosteric regulation is central to many biochemical processes. Allosteric sites provide a target to fine-tune protein activity, yet we lack computational methods to predict them. Here, we present an efficient graph-theoretical approach for identifying allosteric sites and the mediating interactions that connect them to the active site. Using an atomistic graph with edges weighted by covalent and non-covalent bond energies, we obtain a bond-to-bond propensity that quantifies the effect of instantaneous bond fluctuations propagating through the protein. We use this propensity to detect the sites and communication pathways most strongly linked to the active site, assessing their significance through quantile regression and comparison against a reference set of 100 generic proteins. We exemplify our method in detail with three well-studied allosteric proteins: caspase-1, CheY, and h-Ras, correctly predicting the location of the allosteric site and identifying key allosteric interactions. Consistent prediction of...

  4. Development of fricriveting as a new joining technique for polymer and lightweight alloys; Entwicklung des Reibnietens als neues Fuegeverfahren fuer Kunststoff und Leichtbaulegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Amancio-Filho, S.T.; Santos, J.F. dos [GKSS Forschungszentrum GmbH, Institut fuer Werkstoffforschung, Werkstoffmechanik, Geesthacht (Germany)

    2008-11-15

    The increasing demand on environmental consciousness, cost savings and high performance end products has been guiding scientists and engineers to a constant development of new materials and technologies. This class of lightweight structures are specially used in industrial fields such as transportation and modern civil engineering. Currently available joining methods for polymer-metal structures (adhesive bonding and mechanical fastening) are usually application-specific, presenting high operational costs, limited mechanical performance or are not environmental friendly. A new Friction Riveting technique for polymeric-metallic joints was developed, demonstrated and characterized in this work, as an alternative, reliable, environmental compatible and economically viable spot joining process. In the simplest process variant a rotating cylindrical metallic rivet is inserted in one or more thermoplastic base plates. The high rotation speed and pressure increase friction and heat is generated. When the preset time is achieved the temperature highly increases and the rivet tip plasticizes. At this point rotation is decelerated and the axial pressure increased, so the plasticized rivet tip becomes deformed; after cooling it becomes anchored in the polymeric base plate. In this work case-study joints on commercially available polyetherimide (PEI) and aluminium 2024-T351 (Al-Cu-Mg alloy) were chosen for demonstrating proposed theories and mechanisms of FricRiveting. Sound friction riveted point-on-plate and single-rivet overlap joints with elevated joint efficiencies in terms of base materials strength were obtained (tensile joint efficiencies of about 97 % of the rivet strength and shear joint efficiencies of about 70 % of the polymer strength) through tensile and lap shear testing at room temperature. Finally, the microstructural changes and properties were described for this case-study joint. The feasibility of FricRiveting was demonstrated in this work by the presented

  5. Bond markets and banking crises in emerging market economies: The role of institutions

    Directory of Open Access Journals (Sweden)

    Boukhatem Jamel

    2012-01-01

    Full Text Available This paper deals with the question of knowing if countries whose activity of financing is mainly bank based face crises more expensive than those where the bond markets are broader and more developed. The results of the empirical tests on a panel of emerging countries suggest that bank based financial systems are associated with crises slightly more expensive, whereas the relationship between the bond markets and the crises’ costs is fragile. Moreover, financial systems where bond markets play an important role are associated with a higher growth of the production, and this, independently of the presence or not of crises. The consideration of the combined effect of financial liberalization and institutional framework on the bond markets development shows the importance of the direction of the financial liberalization. We join in this case one of the most significant aspects of the “sequencing” theorized by McKinnon (1973. Finally, an effective prudential regulation tends to reduce significantly the probability of occurrence of banking crises.

  6. Bayesian field theoretic reconstruction of bond potential and bond mobility in single molecule force spectroscopy

    CERN Document Server

    Chang, Joshua C; Chou, Tom

    2015-01-01

    Quantifying the forces between and within macromolecules is a necessary first step in understanding the mechanics of molecular structure, protein folding, and enzyme function and performance. In such macromolecular settings, dynamic single-molecule force spectroscopy (DFS) has been used to distort bonds. The resulting responses, in the form of rupture forces, work applied, and trajectories of displacements, have been used to reconstruct bond potentials. Such approaches often rely on simple parameterizations of one-dimensional bond potentials, assumptions on equilibrium starting states, and/or large amounts of trajectory data. Parametric approaches typically fail at inferring complex-shaped bond potentials with multiple minima, while piecewise estimation may not guarantee smooth results with the appropriate behavior at large distances. Existing techniques, particularly those based on work theorems, also do not address spatial variations in the diffusivity that may arise from spatially inhomogeneous coupling to...

  7. Spain to Join ESO

    Science.gov (United States)

    2006-02-01

    /infrared astronomical observing site in Europe and site of the Spanish 10m GranTeCan telescope now nearing completion. With the high quality of Spanish astronomical research as well as the technological competence of Spanish industry, it is only fitting that Spain should join ESO, world-leader in ground-based astronomy. Through ESO Spain will enjoy full access both to all of ESO's current facilities and to unrestricted participation in the great projects that ESO is planning for the future. Spain is already an active partner of the Atacama Large Millimeter Array (ALMA), whose construction and operations are led on behalf of Europe by ESO. ESO's Council approved the admission of Spain at its 107th meeting held in Garching on 7 and 8 December 2005. High resolution images and their captions are available on this page.

  8. Comparison of Shear Bond Strength between Composite Resin and Porcelain Using Different Bonding Systems

    Directory of Open Access Journals (Sweden)

    E.Yassini

    2005-03-01

    Full Text Available Statement of Problem: Ceramics as in ceramo-metallic and all ceramic tooth restorations have grown popular owing to their high tissue compatibility and esthetic advantages. Such restorations have the capability to deliver valuable services over a long period of time; however, failures under intraoral conditions are not unanticipated.Purpose: The purpose of this in-vitro study was to investigate the shear bond strength of composite resin to porcelain using different bonding system materials.Materials and Methods: In this experimental study forty porcelain blocks were prepared and randomly divided into four equal groups. The porcelain surfaces were then etched with HF for 2 minutes, washed with water for 2 minutes and treated with a silane layer. The silane treated porcelain surfaces were left for one minute and then the specimens were bonded to composite resin as follow:Group 1 (control group, hybrid composite Z100 was applied and light cured from four directions for 20 seconds. Group 2, flowable composite was applied and light cured for 20 seconds. Group 3, unfilled resin was used and photo cured for 20 seconds. Group 4,(Dentin bonding agent adhesive resin was used followed by 20 seconds photo curing.Hybrid composite resin Z100 was subsequently applied on all porcelain surfaces of groups 2, 3 and 4, and light cured for 20 seconds from four directions. Specimens were then subjected to thermocycling 1000 times. Shear bond strength was determined by a Universal testing machine. The data obtained was subjected to a one-way ANOVA test.Results: The results indicate that there is a statistically significant difference between adhesive group and the other three groups of hybrid, flowable and unfilled resin (P<0.05.Conclusion: The results from this study showed that the shear bond strength of composite resin to porcelain was significantly higher for porcelain bonded surfaces using a dentin bonding agent than that of other materials tested.

  9. Comparison of the microtensile bond strength of different composite core materials and bonding systems to a fiber post (DT Light

    Directory of Open Access Journals (Sweden)

    Lelya Sadighpour

    2013-10-01

    Full Text Available   Background and Aims: Retention and stability of the post and core system is the key factor for success of final restoration . The aim of this study was to evaluate the microtensile bond strength of the different composite core materials and bonding systems to a fiber post.   Materials and Methods: To evaluate the bond strength of the composite resins to a fiber post ( DT light post 60 posts were divided into six groups : group A: Heliomolar Flow + Seal Bond, group B: Heliomolar Flow + SE Bond , group C: Valux Plus + Seal Bond , group D: Valux Plus + SE Bond , group E: Corecem + Seal Bond, group F: Corecem + SE Bond. All samples were thermocycled for 5000 cycles (5-55 0C and cut into four bars for the microtensile bond strength test. Failure modes were identified using a stereomicroscope. Data were analysed using One-way ANOVA and Tukey HSD post hoc test (P<0.05.   Results: The interaction between composite resin materials and bonding systems were positive. The conventional hybrid composite (Valux Plus had significantly higher bond strength compared with the core specific flowable composite (Corecem when Seal Bond was applied as bonding agent (P<0.05. However, when SE Bond was utilized hybrid composite demonstrated significantly lower bond strength than that of other two groups (P<0.05.   Conclusion: The performance of a particular composite is affected by the bonding system that is applied. A single composite resin may have different bond strength when combined with different bonding system.

  10. Recrafting the Neighbor-Joining Method

    DEFF Research Database (Denmark)

    Mailund; Brodal, Gerth Stølting; Fagerberg, Rolf;

    2006-01-01

    Background: The neighbor-joining method by Saitou and Nei is a widely used method for constructing phylogenetic trees. The formulation of the method gives rise to a canonical Θ(n3) algorithm upon which all existing implementations are based. Methods: In this paper we present techniques for speeding...... up the canonical neighbor-joining method. Our algorithms construct the same phylogenetic trees as the canonical neighbor-joining method. The best-case running time of our algorithms are O(n2) but the worst-case remains O(n3). We empirically evaluate the performance of our algoritms on distance...... neighbor-joining method. Conclusions: The experiments show that our algorithms also yield a significant speed-up, already for medium sized instances....

  11. Temperature effect in thermosonic wire bonding

    Institute of Scientific and Technical Information of China (English)

    WU Yun-xin; LONG Zhi-li; HAN Lei; ZHONG Jue

    2006-01-01

    The temperature effect on bonding strength and ultrasonic transmission in a PZT transducer system was investigated. The results show that, the temperature change influences the material features of the bonding interface, such as elastic modulus, tensile strength of gold ball and Ag substrate, which results in different bonding strengths. Moreover, the temperature change also influences the impedance and dissipative ultrasonic energy in the PZT system. The current signal of PZT transducer was analyzed by join time-frequency analysis, which can reveal the current change in a bonding process more clearly and completely. The analysis shows that the bonding parameters influence mutually. These results can help build some criteria for parameter match and optimization in wire bonding processes.

  12. Shear Bond Strength of Three Orthodontic Bonding Systems on Enamel and Restorative Materials

    Science.gov (United States)

    Ebeling, Jennifer; Schauseil, Michael; Stein, Steffen; Roggendorf, Matthias; Korbmacher-Steiner, Heike

    2016-01-01

    Objective. The aim of this in vitro study was to determine the shear bond strength (SBS) and adhesive remnant index (ARI) score of two self-etching no-mix adhesives (iBond™ and Scotchbond™) on different prosthetic surfaces and enamel, in comparison with the commonly used total etch system Transbond XT™. Materials and Methods. A total of 270 surfaces (1 enamel and 8 restorative surfaces, n = 30) were randomly divided into three adhesive groups. In group 1 (control) brackets were bonded with Transbond XT primer. In the experimental groups iBond adhesive (group 2) and Scotchbond Universal adhesive (group 3) were used. The SBS was measured using a Zwicki 1120™ testing machine. The ARI and SBS were compared statistically using the Kruskal–Wallis test (P ≤ 0.05). Results. Significant differences in SBS and ARI were found between the control group and experimental groups. Conclusions. Transbond XT showed the highest SBS on human enamel. Scotchbond Universal on average provides the best bonding on all other types of surface (metal, composite, and porcelain), with no need for additional primers. It might therefore be helpful for simplifying bonding in orthodontic procedures on restorative materials in patients. If metal brackets have to be bonded to a metal surface, the use of a dual-curing resin is recommended.

  13. Impact of Cohort Bonds on Student Satisfaction and Engagement

    Science.gov (United States)

    Martin, Kimberly A.; Goldwasser, Molly M.; Galentino, Richard

    2017-01-01

    This study examines differences in student satisfaction and engagement in cohort programs versus traditional, non-cohort educational programs by studying the impact of close bonds between students. The authors measure and compare "close bonds" within an educational cohort to a traditional program and measure the impact of close bonds on…

  14. Limitations in Bonding to Dentin and Experimental Strategies to Prevent Bond Degradation

    OpenAIRE

    Liu, Y.; Tjäderhane, L.; Breschi, L; A. Mazzoni; Li, N; J. Mao; Pashley, D.H.; Tay, F.R.

    2011-01-01

    The limited durability of resin-dentin bonds severely compromises the lifetime of tooth-colored restorations. Bond degradation occurs via hydrolysis of suboptimally polymerized hydrophilic resin components and degradation of water-rich, resin-sparse collagen matrices by matrix metalloproteinases (MMPs) and cysteine cathepsins. This review examined data generated over the past three years on five experimental strategies developed by different research groups for extending the longevity of resi...

  15. Comparison of shear bond strength of amalgam bonded to primary and permanent dentin

    OpenAIRE

    Mahdi S; Bahman S; Arghavan A; Fatemeh M

    2008-01-01

    Amalgam′s non-adhesive characteristics necessitate cavity preparations incorporating retentive features, which often require the removal of non-carious tooth structure. Use of adhesives beneath amalgam restorations, would be helpful to overcome this disadvantage. This study was undertaken to compare the mean shear bond strength of amalgam bonded to primary and permanent dentin, to evaluate the efficacy of amalgam adhesives in pediatric dentistry.27 primary and 28 permanent posterior te...

  16. Cooperative effects between tetrel bond and other σ-hole bond interactions: a comparative investigation

    Science.gov (United States)

    Esrafili, Mehdi D.; Nurazar, Roghaye; Mohammadian-Sabet, Fariba

    2015-12-01

    Covalently bonded atoms of Groups IV-VII tend to have anisotropic charge distributions, the electronic densities being less on the extensions of the bonds (σ-holes) than in the intervening regions. These σ-holes often give rise to positive electrostatic potentials through which the atom can interact attractively and highly directionally with negative sites. In this work, cooperative effects between tetrel bond and halogen/chalcogen/pnicogen bond interactions are studied in multi-component YH3M...NCX...NH3 complexes, where Y = F, CN; M = C, Si and X = Cl, SH and PH2. These effects are analysed in detail in terms of the structural, energetic, charge-transfer and electron density properties of the complexes. The nature of the σ-hole bonds is unveiled by quantum theory of atoms in molecules and natural bond orbital theory. A favourable cooperativity is found with values that range between -0.34 and -1.15 kcal/mol. Many-body decomposition of interaction energies indicate that two-body energy term is the most important source of the attraction, which its contribution accounts for 87%-96% of the total interaction energy.

  17. Development finance via diaspora bonds track record and potential

    OpenAIRE

    Ketkar, Suhas L.; Ratha, Dilip

    2004-01-01

    A diaspora bond is a debt instrument issued by a country - or potentially, a sub-sovereign entity or a private corporation - to raise financing from its overseas diaspora. Israel and India have raised $35-40 billion using these bonds. Drawing on their experiences, this paper discusses the rationale, methodology, and factors affecting the issuance of diaspora bonds for raising external deve...

  18. Continuing relationships with the deceased : disentangling bonds and grief

    NARCIS (Netherlands)

    Schut, Henk A W; Stroebe, Margaret S; Boelen, Paul A; Zijerveld, Annemieke M

    2006-01-01

    Some studies of the relationship between continuing bonds and grief intensity have claimed that continuing bonds lead to poor adaptation to bereavement. However, operationalizations of continuing bonds and grief intensity appear to overlap conceptually. Thus, it is still unclear what character the c

  19. The bond length and bond energy of gaseous CrW.

    Science.gov (United States)

    Matthew, Daniel J; Oh, Sang Hoon; Sevy, Andrew; Morse, Michael D

    2016-06-07

    Supersonically cooled CrW was studied using resonant two-photon ionization spectroscopy. The vibronically resolved spectrum was recorded over the region 21 100 to 23 400 cm(-1), showing a very large number of bands. Seventeen of these bands, across three different isotopologues, were rotationally resolved and analyzed. All were found to arise from the ground (1)Σ(+) state of the molecule and to terminate on states with Ω' = 0. The average r0 bond length across the three isotopic forms was determined to be 1.8814(4) Å. A predissociation threshold was observed in this dense manifold of vibronic states at 23 127(10) cm(-1), indicating a bond dissociation energy of D0(CrW) = 2.867(1) eV. Using the multiple bonding radius determined for atomic Cr in previous work, the multiple bonding radius for tungsten was calculated to be 1.037 Å. Comparisons are made between CrW and the previously investigated group 6 diatomic metals, Cr2, CrMo, and Mo2, and to previous computational studies of this molecule. It is also found that the accurately known bond dissociation energies of group 5/6 metal diatomics Cr2, V2, CrW, NbCr, VNb, Mo2, and Nb2 display a qualitative linear dependence on the sum of the d-orbital radial expectation values, r; this relationship allows the bond dissociation energies of other molecules of this type to be estimated.

  20. Joining up health and planning: how Joint Strategic Needs Assessment (JSNA) can inform health and wellbeing strategies and spatial planning.

    Science.gov (United States)

    Tomlinson, Paul; Hewitt, Stephen; Blackshaw, Neil

    2013-09-01

    There has been a welcome joining up of the rhetoric around health, the environment and land use or spatial planning in both the English public health white paper and the National Planning Policy Framework. However, this paper highlights a real concern that this is not being followed through into practical guidance needed by local authorities (LAs), health bodies and developers about how to deliver this at the local level. The role of Joint Strategic Needs Assessments (JSNAs) and Health and Wellbeing Strategies (HWSs) have the potential to provide a strong basis for integrated local policies for health improvement, to address the wider determinants of health and to reduce inequities. However, the draft JSNA guidance from the Department of Health falls short of providing a robust, comprehensive and practical guide to meeting these very significant challenges. The paper identifies some examples of good practice. It recommends that action should be taken to raise the standards of all JSNAs to meet the new challenges and that HWSs should be aligned spatially and temporally with local plans and other LA strategies. HWSs should also identify spatially targeted interventions that can be delivered through spatial planning or transport planning. Steps need to be taken to ensure that district councils are brought into the process.

  1. Comparison of shear bond strength of amalgam bonded to primary and permanent dentin.

    Science.gov (United States)

    Mahdi, S; Bahman, S; Arghavan, A B; Fatemeh, M

    2008-06-01

    Amalgam's non-adhesive characteristics necessitate cavity preparations incorporating retentive features, which often require the removal of non-carious tooth structure. Use of adhesives beneath amalgam restorations, would be helpful to overcome this disadvantage. This study was undertaken to compare the mean shear bond strength of amalgam bonded to primary and permanent dentin, to evaluate the efficacy of amalgam adhesives in pediatric dentistry.27 primary and 28 permanent posterior teeth with intact buccal or lingual surfaces were grounded to expose dentin and wet-polished with 400-grit silicone carbide paper. Scotchbond Multi Purpose Plus adhesive system was applied to the dentin surfaces and light cured. Amalgam was condensed onto the treated dentin through a plastic mold.shear bond strength testing was done using an Instron Universal testing machine, at a crosshead speed of 0.5 mm/min.The data were analyzed by independent samples t-test The difference among the two groups was not statistically significant (p>0.05) Bonded amalgam showed the same level of bond strength to primary and permanent dentin; so, application of amalgam bonding agents in pediatric dentistry can be recommended.

  2. Comparison of shear bond strength of amalgam bonded to primary and permanent dentin

    Directory of Open Access Journals (Sweden)

    Mahdi S

    2008-06-01

    Full Text Available Amalgam′s non-adhesive characteristics necessitate cavity preparations incorporating retentive features, which often require the removal of non-carious tooth structure. Use of adhesives beneath amalgam restorations, would be helpful to overcome this disadvantage. This study was undertaken to compare the mean shear bond strength of amalgam bonded to primary and permanent dentin, to evaluate the efficacy of amalgam adhesives in pediatric dentistry.27 primary and 28 permanent posterior teeth with intact buccal or lingual surfaces were grounded to expose dentin and wet-polished with 400-grit silicone carbide paper. Scotchbond Multi Purpose Plus adhesive system was applied to the dentin surfaces and light cured. Amalgam was condensed onto the treated dentin through a plastic mold.shear bond strength testing was done using an Instron Universal testing machine, at a crosshead speed of 0.5 mm/min.The data were analyzed by independent samples t-test The difference among the two groups was not statistically significant (p>0.05 Bonded amalgam showed the same level of bond strength to primary and permanent dentin; so, application of amalgam bonding agents in pediatric dentistry can be recommended.

  3. Speeding Up Neighbour-Joining Tree Construction

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf; Mailund, Thomas

    A widely used method for constructing phylogenetic trees is the neighbour-joining method of Saitou and Nei. We develope heuristics for speeding up the neighbour-joining method which generate the same phylogenetic trees as the original method. All heuristics are based on using a quad-tree to guide...... the search for the next pair of nodes to join, but di#er in the information stored in quad-tree nodes, the way the search is performed, and in the way the quad-tree is updated after a join. We empirically evaluate the performance of the heuristics on distance matrices obtained from the Pfam collection...... of alignments, and compare the running time with that of the QuickTree tool, a well-known and widely used implementation of the standard neighbour-joining method. The results show that the presented heuristics can give a significant speed-up over the standard neighbour-joining method, already for medium sized...

  4. Students' Perceptions of Parental Bonding Styles and Their Academic Burnout

    Science.gov (United States)

    Shin, Hyojung; Lee, Jayoung; Kim, Boyoung; Lee, Sang Min

    2012-01-01

    This study investigated how parental bonding style affects academic burnout in Korean adolescents. Participants were 447 middle school students, who completed the Parental Bonding Instrument and the Maslach Burnout Inventory-Student Survey. MANCOVA results confirmed that adolescents reporting the optimal bonding parental style, for both mother and…

  5. Diffusion Bonding Beryllium to Reduced Activation Ferritic Martensitic Steel: Development of Processes and Techniques

    Science.gov (United States)

    Hunt, Ryan Matthew

    Only a few materials are suitable to act as armor layers against the thermal and particle loads produced by magnetically confined fusion. These candidates include beryllium, tungsten, and carbon fiber composites. The armor layers must be joined to the plasma facing components with high strength bonds that can withstand the thermal stresses resulting from differential thermal expansion. While specific joints have been developed for use in ITER (an experimental reactor in France), including beryllium to CuCrZr as well as tungsten to stainless steel interfaces, joints specific to commercially relevant fusion reactors are not as well established. Commercial first wall components will likely be constructed front Reduced Activation Ferritic Martensitic (RAFM) steel, which will need to be coating with one of the three candidate materials. Of the candidates, beryllium is particularly difficult to bond, because it reacts during bonding with most elements to form brittle intermetallic compounds. This brittleness is unacceptable, as it can lead to interface crack propagation and delamination of the armor layer. I have attempted to overcome the brittle behavior of beryllium bonds by developing a diffusion bonding process of beryllium to RAFM steel that achieves a higher degree of ductility. This process utilized two bonding aids to achieve a robust bond: a. copper interlayer to add ductility to the joint, and a titanium interlayer to prevent beryllium from forming unwanted Be-Cu intermetallics. In addition, I conducted a series of numerical simulations to predict the effect of these bonding aids on the residual stress in the interface. Lastly, I fabricated and characterized beryllium to ferritic steel diffusion bonds using various bonding parameters and bonding aids. Through the above research, I developed a process to diffusion bond beryllium to ferritic steel with a 150 M Pa tensile strength and 168 M Pa shear strength. This strength was achieved using a Hot Isostatic

  6. Intramolecular hydrogen bonding in myricetin and myricitrin

    DEFF Research Database (Denmark)

    Vojta, Danijela; Dominkovic, Katarina; Miljanic, Snezana;

    2016-01-01

    The molecular structures of myricetin (3,3’,4’,5,5’,7-hexahydroxyflavone; MCE) and myricitrin (myricetin 3-O-rhamnoside; MCI) are investigated by quantum chemical calculations (B3LYP/6-311G**). Two preferred molecular rotamers of MCI are predicted, corresponding to different conformations of the O......-rhamnoside subunit. The rotamers are characterized by different hydrogen bonded cross-links between the hydroxy groups of the rhamnoside substituent and the parent MCE moiety. The predicted OH stretching frequencies are compared with vibrational spectra of MCE and MCI recorded for the sake of this investigation (IR...

  7. Intramolecular hydrogen bonding in myricetin and myricitrin

    DEFF Research Database (Denmark)

    Vojta, Danijela; Dominkovic, Katarina; Miljanic, Snezana;

    2017-01-01

    The molecular structures of myricetin (3,3’,4’,5,5’,7-hexahydroxyflavone; MCE) and myricitrin (myricetin 3-O-rhamnoside; MCI) are investigated by quantum chemical calculations (B3LYP/6-311G**). Two preferred molecular rotamers of MCI are predicted, corresponding to different conformations of the O......-rhamnoside subunit. The rotamers are characterized by different hydrogen bonded cross-links between the hydroxy groups of the rhamnoside substituent and the parent MCE moiety. The predicted OH stretching frequencies are compared with vibrational spectra of MCE and MCI recorded for the sake of this investigation (IR...

  8. The chemical bond structure and dynamics

    CERN Document Server

    Zewail, Ahmed

    1992-01-01

    This inspired book by some of the most influential scientists of our time--including six Nobel laureates--chronicles our emerging understanding of the chemical bond through the last nine decades and into the future. From Pauling's early structural work using x-ray and electron diffraction to Zewail's femtosecond lasers that probe molecular dynamics in real time; from Crick's molecular biology to Rich's molecular recognition, this book explores a rich tradition of scientific heritage and accomplishment. The perspectives given by Pauling, Perutz, Rich, Crick, Porter, Polanyi, Herschbach, Zewail,

  9. Change of gene structure and function by non-homologous end-joining, homologous recombination, and transposition of DNA.

    Directory of Open Access Journals (Sweden)

    Wolfgang Goettel

    2009-06-01

    Full Text Available An important objective in genome research is to relate genome structure to gene function. Sequence comparisons among orthologous and paralogous genes and their allelic variants can reveal sequences of functional significance. Here, we describe a 379-kb region on chromosome 1 of maize that enables us to reconstruct chromosome breakage, transposition, non-homologous end-joining, and homologous recombination events. Such a high-density composition of various mechanisms in a small chromosomal interval exemplifies the evolution of gene regulation and allelic diversity in general. It also illustrates the evolutionary pace of changes in plants, where many of the above mechanisms are of somatic origin. In contrast to animals, somatic alterations can easily be transmitted through meiosis because the germline in plants is contiguous to somatic tissue, permitting the recovery of such chromosomal rearrangements. The analyzed region contains the P1-wr allele, a variant of the genetically well-defined p1 gene, which encodes a Myb-like transcriptional activator in maize. The P1-wr allele consists of eleven nearly perfect P1-wr 12-kb repeats that are arranged in a tandem head-to-tail array. Although a technical challenge to sequence such a structure by shotgun sequencing, we overcame this problem by subcloning each repeat and ordering them based on nucleotide variations. These polymorphisms were also critical for recombination and expression analysis in presence and absence of the trans-acting epigenetic factor Ufo1. Interestingly, chimeras of the p1 and p2 genes, p2/p1 and p1/p2, are framing the P1-wr cluster. Reconstruction of sequence amplification steps at the p locus showed the evolution from a single Myb-homolog to the multi-gene P1-wr cluster. It also demonstrates how non-homologous end-joining can create novel gene fusions. Comparisons to orthologous regions in sorghum and rice also indicate a greater instability of the maize genome, probably due to

  10. Hydrogen bonding in asphaltenes and coal

    Energy Technology Data Exchange (ETDEWEB)

    Li, N.C.; Tewari, K.C.

    1978-04-01

    The objective of this program is to investigate and to determine the nature of hydrogen bonding and other molecular interactions that occur in asphaltene and coal liquids, and to seek possible correlations between the interactions and the viscosity. The asphaltene components of samples of centrifuged liquid product, CLP, and solvent-refined coal, SRC, supplied by the Pittsburgh Energy Research Center, are isolated by solvent fractionation. The compositions of the asphaltenes are obtained by elemental analysis and the molecular weights by vapor pressure osmometry. The acid/neutral and base components of the asphaltenes are separated and again elemental analysis and molecular weights are obtained. The magnetic resonance, infrared and calorimetric methods are used to determine the strength of hydrogen-bond and other molecular interactions in the fractions isolated. Investigations on the toluene-insoluble and heavy-oil fractions are also carried out. In addition, extensive proton magnetic resonance, near infrared and calorimetric studies are carried out for o-phenylphenol and quinoline, which serve as model compounds for the aromatic phenols and the heteronuclear aromatic base nitrogens, respectively, found in coal liquefaction products. This is the final report, giving a summary of activities under the Contract for the entire period.

  11. Theoretical study for Bond between Reinforcement steel and Concrete

    Directory of Open Access Journals (Sweden)

    usama mostafa mahran

    2013-04-01

    Full Text Available The behavior and load carrying behavior of reinforced concrete structures is influence by the interaction between the concrete and reinforcement. The stress transfer between reinforcement and concrete in the longitudinal direction of the bars is called bond. An essential feature of reinforced concrete is the bond between steel and concrete. Anchorage of reinforcement depends on the bond between steel and concrete, crack width and crack spacing are mainly governed by it. So, stiffness, deformation and dynamic behavior are influenced by it, and in reverse loading damping and energy dissipation is a function of bond. This is one of the reasons why bond has been, and still is, a topic of fundamental and applied research. Bond stress is the equivalent unit shear stress acting in parallel to the reinforcing bar on the interface between reinforcing steel bar and concrete. Due to the transfer of forces through bond stress, between the reinforcing rebar and concrete, the force in the reinforcing bar changes along its length. Because bond stress is thought of as stress per unit area of bar surface, it is related to the rate of change of steel stress. Consequently, to have bond stress it is necessary to have a changing steel stress. In cases of high stress at the contact interface, near cracks or end anchorages, the bond stresses are related to relative displacements between concrete and steel. These relative displacements, which are caused by different average strains in the concrete and the steel, are usually called bond-slip (t-d.

  12. The binding energy and bonding in dialane.

    Science.gov (United States)

    Goebbert, Daniel J; Hernandez, Heriberto; Francisco, Joseph S; Wenthold, Paul G

    2005-08-24

    The binding energy of dialane, Al2H6, has been measured using mass spectrometric techniques to be 33 +/- 5 kcal/mol. This represents the first measurement of the thermochemical properties of dialane, which has only recently been observed in low-temperature matricies. High-level quantum mechanical calculations give a binding energy in agreement with the measured value. Experimental and quantum mechanical calculations show that dialane is chemically similar to diborane, B2H6, even though the bonding for these two systems shows significant differences.

  13. Advances in modeling and design of adhesively bonded systems

    CERN Document Server

    Kumar, S

    2013-01-01

    The book comprehensively charts a way for industry to employ adhesively bonded joints to make systems more efficient and cost-effective Adhesively bonded systems have found applications in a wide spectrum of industries (e.g., aerospace, electronics, construction, ship building, biomedical, etc.) for a variety of purposes. Emerging adhesive materials with improved mechanical properties have allowed adhesion strength approaching that of the bonded materials themselves. Due to advances in adhesive materials and the many potential merits that adhesive bonding offers, adhesive bonding has replac

  14. Why join the Staff Association

    CERN Multimedia

    Association du personnel

    2011-01-01

    Becoming a member of the Staff Association (SA) is above all a personal choice, showing that the joining person’s commitment and adherence to values such as solidarity, social cohesion, etc.In September, the SA launches a membership campaign to convince a maximum number to join, to inform, arouse interest and support. Posters, emails and individual contacts are part of the campaign programme, just like this editorial. As far as individual contacts are concerned, we ask you to give time and lend an ear to the delegates of your department in the Staff Council, who will approach you, in order to make an open and constructive discussion possible. Do not hesitate to ask questions and let them know your thoughts about the SA, as (constructive) criticism enables us to progress. The Staff Association and its role of collective representation The Staff Association, via its delegates, represents collectively all staff of the Organization before the Director-General and Member States. To do this, staff rep...

  15. Tetrahedrality and hydrogen bonds in water

    Science.gov (United States)

    Székely, Eszter; Varga, Imre K.; Baranyai, András

    2016-06-01

    We carried out extensive calculations of liquid water at different temperatures and pressures using the BK3 model suggested recently [P. T. Kiss and A. Baranyai, J. Chem. Phys. 138, 204507 (2013)]. In particular, we were interested in undercooled regions to observe the propensity of water to form tetrahedral coordination of closest neighbors around a central molecule. We compared the found tetrahedral order with the number of hydrogen bonds and with the partial pair correlation functions unfolded as distributions of the closest, the second closest, etc. neighbors. We found that contrary to the number of hydrogen bonds, tetrahedrality changes substantially with state variables. Not only the number of tetrahedral arrangements increases with lowering the pressure, the density, and the temperature but the domain size of connecting tetrahedral structures as well. The difference in tetrahedrality is very pronounced between the two sides of the Widom line and even more so between the low density amorphous (LDA) and high density amorphous (HDA) phases. We observed that in liquid water and in HDA, the 5th water molecule, contrary to ice and LDA, is positioned between the first and the second coordination shell. We found no convincing evidence of structural heterogeneity or regions referring to structural transition.

  16. Dynamic Strength Evaluations for Self-Piercing Rivets and Resistance Spot Welds Joining Similar and Dissimilar Metals

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xin; Khaleel, Mohammad A.

    2007-10-01

    This paper summarizes the dynamic joint strength evaluation procedures and the measured dynamic strength data for thirteen joint populations of self-piercing rivets (SPR) and resistance spot welds (RSW) joining similar and dissimilar metals. A state-of-the-art review of the current practice for conducting dynamic tensile/compressive strength tests in different strain rate regimes is first presented, and the generic issues associated with dynamic strength test are addressed. Then, the joint strength testing procedures and fixture designs used in the current study are described, and the typical load versus displacement curves under different loading configurations are presented. Uniqueness of the current data compared with data in the open literature is discussed. The experimental results for all the joint populations indicate that joint strength increases with increasing loading rate. However, the strength increase from 4.47m/s (10mph) to 8.94m/s (20mph) is not as significant as the strength increase from static to 4.47m/s. It is also found that with increasing loading velocity, displacement to failure decreases for all the joint samples. Therefore, “brittleness” of the joint sample increases with impact velocity. Detailed static and dynamic strength data and the associated energy absorption levels for all the samples in the thirteen joint populations are also included.

  17. Flexible Friction Stir Joining Technology

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lim, Yong Chae [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mahoney, Murray [MegaStir Technologies LLC, Orem, UT (United States); Sanderson, Samuel [MegaStir Technologies LLC, Orem, UT (United States); Larsen, Steve [MegaStir Technologies LLC, Orem, UT (United States); Steel, Russel [MegaStir Technologies LLC, Orem, UT (United States); Fleck, Dale [MegaStir Technologies LLC, Orem, UT (United States); Fairchild, Doug P [ExxonMobil, Upstream Research Company (URC), Houston, TX (United States); Wasson, Andrew J [ExxonMobil, Upstream Research Company (URC), Houston, TX (United States); Babb, Jon [MegaStir Technologies LLC, Orem, UT (United States); Higgins, Paul [MegaStir Technologies LLC, Orem, UT (United States)

    2015-07-23

    Reported herein is the final report on a U.S. Department of Energy (DOE) Advanced Manufacturing Office (AMO) project with industry cost-share that was jointly carried out by Oak Ridge National Laboratory (ORNL), ExxonMobil Upstream Research Company (ExxonMobil), and MegaStir Technologies (MegaStir). The project was aimed to advance the state of the art of friction stir welding (FSW) technology, a highly energy-efficient solid-state joining process, for field deployable, on-site fabrications of large, complex and thick-sectioned structures of high-performance and high-temperature materials. The technology innovations developed herein attempted to address two fundamental shortcomings of FSW: 1) the inability for on-site welding and 2) the inability to weld thick section steels, both of which have impeded widespread use of FSW in manufacturing. Through this work, major advance has been made toward transforming FSW technology from a “specialty” process to a mainstream materials joining technology to realize its pervasive energy, environmental, and economic benefits across industry.

  18. Strength and leak testing of plasma activated bonded interfaces

    DEFF Research Database (Denmark)

    Visser, M.M.; Weichel, Steen; Reus, Roger De

    2002-01-01

    Bond strength and hermeticity of plasma activated bonded (PAB) Si-Si interfaces are reported. Bonding of 100 mm Si(1 0 0) wafers was performed. An average bond strength of 9.0+/-3.9 MPa was achieved without performing any annealing steps. Cavities bonded in vacuum were found to be hermetic based...... on detection of changes in membrane deflections. The detection limit for leak was 8E-13 mbar l/s. For comparison, strength and leak tests were also performed with regular fusion bonded wafers annealed at 1100 degreesC. The PAB was found to withstand post-processing steps such as RCA cleaning, 24 h in de......-ionised water (DIW), 24 h in 2.5% HF, 24 h in acetone and 60 s in a resist developer. By analysing the thin silicon oxide present on the surfaces to be bonded with optical methods, the influence of pre-cleaning and activation process parameters was investigated....

  19. Functional intersection of ATM and DNA-dependent protein kinase catalytic subunit in coding end joining during V(D)J recombination

    DEFF Research Database (Denmark)

    Lee, Baeck-Seung; Gapud, Eric J; Zhang, Shichuan

    2013-01-01

    -PKcs deficiency leads to a nearly complete block in coding join formation, as DNA-PKcs is required to activate Artemis, the endonuclease that opens hairpin-sealed coding ends. In contrast to loss of DNA-PKcs protein, here we show that inhibition of DNA-PKcs kinase activity has no effect on coding join formation...... when ATM is present and its kinase activity is intact. The ability of ATM to compensate for DNA-PKcs kinase activity depends on the integrity of three threonines in DNA-PKcs that are phosphorylation targets of ATM, suggesting that ATM can modulate DNA-PKcs activity through direct phosphorylation of DNA...

  20. Market presence in China strengthened Network growth and Dual-Chinese-Hub Strategy More frequet Flyer Benefit——Air China and shanhai Airlines Join Star Alliance

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ In the end of 2007, Air China Limited (hereinafter "Air China") and Shanghai Airlines, formally joined Star Alliance at a ceremony held in the new Terminal Three at Beijing Capital International Airport. With the addition of the two Chinese airlines, Star Alliance now has 19 member carriers operating 17,000 daily flights to 897 destinations in 160 countries.

  1. SUPERPLASTICITY AND DIFFUSION BONDING OF IN718 SUPERALLOY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The superplasticity and diffusion bonding of IN718 superalloy were studied in this article. The strain rate sensitivity index m was obtained at different temperatures and various initial strain rates using the tensile speed mutation method; m reached its maximum value 0.53 at an initial strain rate of 1 ×10-4s-1 at 1253K. The diffusion bonding parameters, including the bonding temperature T,pressure p, and time t, affected the mechanism of joints. When the bonded specimen with 25μm thick nickel foil interlayer was tensile at room temperature, the shear fracture of the joints with nickel foil interlayer took place at the IN718 part. Microstructure study was carried out with the bonded samples. The microstructure shows an excellent bonding at the interfaces. The optimum parameters for the diffusion bonding are: T= 1273-1323K, p = 20-30MPa, t = 45-60min.

  2. Fabrication and integrity test preparation of HIP-joined W and ferritic-martensitic steel mockups for fusion reactor development

    Science.gov (United States)

    Lee, Dong Won; Shin, Kyu In; Kim, Suk Kwon; Jin, Hyung Gon; Lee, Eo Hwak; Yoon, Jae Sung; Choi, Bo Guen; Moon, Se Youn; Hong, Bong Guen

    2014-10-01

    Tungsten (W) and ferritic-martensitic steel (FMS) as armor and structural materials, respectively, are the major candidates for plasma-facing components (PFCs) such as the blanket first wall (BFW) and the divertor, in a fusion reactor. In the present study, three W/FMS mockups were successfully fabricated using a hot isostatic pressing (HIP, 900 °C, 100 MPa, 1.5 hrs) with a following post-HIP heat treatment (PHHT, tempering, 750 °C, 70 MPa, 2 hrs), and the W/FMS joining method was developed based on the ITER BFW and the test blanket module (TBM) development project from 2004 to the present. Using a 10-MHz-frequency flat-type probe to ultrasonically test of the joint, we found no defects in the fabricated mockups. For confirmation of the joint integrity, a high heat flux test will be performed up to the thermal lifetime of the mockup under the proper test conditions. These conditions were determined through a preliminary analysis with conventional codes such as ANSYS-CFX for thermal-hydraulic conditions considering the test facility, the Korea heat load test facility with an electron beam (KoHLT-EB), and its water coolant system at the Korea Atomic Energy Research Institute (KAERI).

  3. Reactive diffusion bonding of SiCp/Al composites by insert layers of mixed Al-Si and Al-Si-SiC powders

    Institute of Scientific and Technical Information of China (English)

    Jihua Huang; Yueling Dong; Yun Wan; Jiangang Zhang; Hua Zhang

    2005-01-01

    Mixed Al-Si and Al-Si-SiC powders were employed as insert layers to reactive diffusion bond SiCp/6063 MMC (metal matrix composites). The results show that SiCp/6063 MMC joints bonded by the insert layer of the mixed Al-Si powder have a dense joining layer with a typical hypoeutectic microstructure. Using the mixed Al-Si-SiC powder as the insert layer, SiCp/6063 MMC can be reactive diffusion bonded by a composite joint. Because of the SiC segregation, however, there are a number of porous zones in the joining layer, which results in the bad shear strength of the joints reactive diffusion bonded by the insert layer of the mixed Al-SiSiC powder, even lower than that of the joints reactive diffusion bonded by the insert layer of the mixed Al-Si powder. Ti and Mg added in the insert layers obviously improve the strength of the joints reactive diffusion bonded by the insert layer of the mixed AlSi-SiC powder, especially, Mg has a more obvious effect.

  4. Limitations in bonding to dentin and experimental strategies to prevent bond degradation.

    Science.gov (United States)

    Liu, Y; Tjäderhane, L; Breschi, L; Mazzoni, A; Li, N; Mao, J; Pashley, D H; Tay, F R

    2011-08-01

    The limited durability of resin-dentin bonds severely compromises the lifetime of tooth-colored restorations. Bond degradation occurs via hydrolysis of suboptimally polymerized hydrophilic resin components and degradation of water-rich, resin-sparse collagen matrices by matrix metalloproteinases (MMPs) and cysteine cathepsins. This review examined data generated over the past three years on five experimental strategies developed by different research groups for extending the longevity of resin-dentin bonds. They include: (1) increasing the degree of conversion and esterase resistance of hydrophilic adhesives; (2) the use of broad-spectrum inhibitors of collagenolytic enzymes, including novel inhibitor functional groups grafted to methacrylate resins monomers to produce anti-MMP adhesives; (3) the use of cross-linking agents for silencing the activities of MMP and cathepsins that irreversibly alter the 3-D structures of their catalytic/allosteric domains; (4) ethanol wet-bonding with hydrophobic resins to completely replace water from the extrafibrillar and intrafibrillar collagen compartments and immobilize the collagenolytic enzymes; and (5) biomimetic remineralization of the water-filled collagen matrix using analogs of matrix proteins to progressively replace water with intrafibrillar and extrafibrillar apatites to exclude exogenous collagenolytic enzymes and fossilize endogenous collagenolytic enzymes. A combination of several of these strategies should result in overcoming the critical barriers to progress currently encountered in dentin bonding.

  5. Measurement of bonding energy in an anhydrous nitrogen atmosphere and its application to silicon direct bonding technology

    Science.gov (United States)

    Fournel, F.; Continni, L.; Morales, C.; Da Fonseca, J.; Moriceau, H.; Rieutord, F.; Barthelemy, A.; Radu, I.

    2012-05-01

    Bonding energy represents an important parameter for direct bonding applications as well as for the elaboration of physical mechanisms at bonding interfaces. Measurement of bonding energy using double cantilever beam (DCB) under prescribed displacement is the most used technique thanks to its simplicity. The measurements are typically done in standard atmosphere with relative humidity above 30%. Therefore, the obtained bonding energies are strongly impacted by the water stress corrosion at the bonding interfaces. This paper presents measurements of bonding energies of directly bonded silicon wafers under anhydrous nitrogen conditions in order to prevent the water stress corrosion effect. It is shown that the measurements under anhydrous nitrogen conditions (less than 0.2 ppm of water in nitrogen) lead to high stable debonding lengths under static load and to higher bonding energies compared to the values measured under standard ambient conditions. Moreover, the bonding energies of Si/SiO2 or SiO2/SiO2 bonding interfaces are measured overall the classical post bond annealing temperature range. These new results allow to revisit the reported bonding mechanisms and to highlight physical and chemical phenomena in the absence of stress corrosion effect.

  6. Comparison of shear bond strength between unfilled resin to dry enamel and dentin bonding to moist and dry enamel

    Directory of Open Access Journals (Sweden)

    Yasini E.

    2005-05-01

    Full Text Available Statement of Problem: The use of dentine bondings on enamel and dentin in total etch protocols has recently become popular. Unfilled resin is hydrophobic and dentin bonding is hydrophilic in nature. This chemical difference could be effective in enamel bonding process. Purpose: The aim of this study was to compare the shear bond strength of unfilled resin to dry enamel and dentin bonding to dry and moist enamel. Materials and Methods: In this experimental study, a total of 30 incisor teeth were used. The specimens were randomly assigned to three groups of 10. 37% phosphoric acid etchant was applied to the enamel surfaces in each group for 15 seconds, rinsed with water for 20 seconds and dried for 20 seconds with compressed air in groups one and two. After conditioning, group 1 received unfilled resin (Margin Bond, Colten and group 2 received dentin bonding (Single Bond, 3M and in group 3 after conditioning and rinsing with water, a layer of dentin bonding (Single Bond was applied on wet enamel. The enamel and dentin bonding were light cured for 20 seconds. A ring mold 3.5 mm in diameter and 2 mm height was placed over the specimens to receive the composite filling material (Z100, 3M. The composite was cured for 40 seconds. The specimens were thermocycled and shear bond strengths were determined using an Instron Universal Testing Machine. The findings were analyzed by ANOVA One-Way and Tukey HSD tests. Results: Shear bond strength of dentin bonding to dry enamel was significantly less than unfilled resin to dry enamel (P<0.05. There was no significant difference between the bond strength of dentin bonding to moist and dry enamel. In addition bond strength of dentin bonding to wet enamel was not significantly different from unfilled resin to dry enamel. Conclusion: Based on the findings of this study, it is suggested that enamel surface should remain slightly moist after etching before bonding with single bond but when using unfilled resin, the

  7. Electric field effects on one-bond indirect spin-spin coupling constants and possible biomolecular perspectives.

    Science.gov (United States)

    Sahakyan, Aleksandr B; Shahkhatuni, Aleksan G; Shahkhatuni, Astghik A; Panosyan, Henry A

    2008-04-24

    Electric field (EF) induced changes of one-bond indirect spin-spin coupling constants are investigated on a wide range of molecules including peptide models. EFs were both externally applied and internally calculated without external EF application by the hybrid density functional theory method. Reliable agreement with experimental data has been obtained for calculated one-bond J-couplings. The role of the EF sign and direction, internal and induced components, hydrogen bonding, internuclear distance and hyperconjugative interactions on the one-bond J-coupling vs EF interconnection is analyzed. A linear dependence of 1J on EF projection along the bond is obtained, if the bound atoms possess different enough electron densities and an EF determined by the electronic polarization exists along the bond. Accentuating the 1JNH couplings as possible EF sensitive parameters, a systematic study is done in two sets of molecules with a large variation of the native internal EF value. The most EF affected component of the 1JNH coupling constant is the spin-dipole term of Ramsey's formulation; however, in the total J-coupling formation, the EF influence on the Fermi contact term is the most significant. The induced EF projection along the bond is 6.7 times weaker in magnitude than the simulated external uniform field. The absolute EF dependence of the one-bond J-coupling involves only the internal field, which is the sum of the induced field (if the external field exists) and the internuclear field determined by the native polarization. That linear and universal dependence joins the corresponding couplings in a diverse set of molecules under various electrostatic conditions. Many types of the one-bond J-couplings can be potentially measured in biomolecules, and the study of their relation with the electrostatic properties at the corresponding sites opens a new avenue to the full exploitation of the NMR measurable parameters with novel and exciting applications.

  8. Molecular mechanics on bonding and non-bonding interactions in (atom@C60)

    Institute of Scientific and Technical Information of China (English)

    朱传宝; 徐志谨; 严继民

    1997-01-01

    The interactions between the embedded atom X (X=Li,Na,K,Rb,Cs; F,Cl,Br,I) and C60cage in the endohedral-form complexes (X@C60) are calculated and discussed according to molecular mechanics from the point of view of the bonding and non-bonding.It is found from the computational results that for atoms with radii larger than Li’s,their locations with the minimum interaction in (X@C60) are at the cage center,while atom Li has an off-center location with the minimum interaction deviation of-0.05 nm,and the cage-environment in C60 can be regarded as sphero-symmetry in the region with radius r of ~0.2 nm.It is shown that the interaction between X and C60 cage is of non-bonding characteristic,and this non-bonding interaction is not purely electrostatic.The repulsion and dispersion in non-bonding interactions should not be neglected,which make important contribution to the location with minimum interaction of X,at center or off center.Some rules about the variations of interactions with atomic radii have been ob

  9. The effect of repeated bonding on the shear bond strength of different resin cements to enamel and dentin

    Science.gov (United States)

    Atsü, Saadet Sağlam

    2017-01-01

    PURPOSE Cementation failures of restorations are frequently observed in clinical practice. The purpose of this study is to compare the effect of initial and repeated bonding on the bond strengths of different resin cements to enamel and dentin. MATERIALS AND METHODS Ninety human maxillary central incisors were bisected longitudinally. The 180 tooth halves were divided into 2 groups (n = 90) for enamel and dentin bonding. The enamel and dentin groups were further divided into 3 groups (n = 30) for different resin cement types. Composite resin (Filtek Ultimate) cylinders (3 × 3 mm) were prepared and luted to enamel and dentin using Variolink II (Group V), RelyX ARC (Group R), or Panavia F 2.0 (Group P) resin cement. After 24 hours, initial shear bond strengths of the resin cements to enamel and dentin were measured. Using new cylinders, the specimens were de-bonded and re-bonded twice to measure the first and the second bond strengths to enamel and dentin. Failure modes and bonding interfaces were examined. Data were statistically analyzed. RESULTS Initial and repeated bond strengths to enamel were similar for all the groups. The first (15.3 ± 2.2 MPa) and second (10.4 ± 2.2 MPa) bond strengths to dentin were significantly higher in Group V (P<.0001). Second bond strengths of dentin groups were significantly lower than initial and first bond strengths to dentin (P<.0001). CONCLUSION All resin cements have similar initial and repeated bond strengths to enamel. Variolink II has the highest first and second bond strength to dentin. Bond strength to dentin decreases after the first re-bonding for all resin cements. PMID:28243393

  10. Porcelain laminate veneer restorations bonded with a three-liquid silane bonding agent and a dual-activated luting composite.

    Science.gov (United States)

    Matsumura, Hideo; Aida, Yukiko; Ishikawa, Yumi; Tanoue, Naomi

    2006-12-01

    This clinical report describes the fabrication and bonding of porcelain laminate veneer restorations in a patient with anterior open spaces. Laminate veneer restorations made of feldspathic porcelain were etched with 5% hydrofluoric acid, rinsed under tap water, ultrasonically cleaned with methanol, and primed with a chemically activated three-liquid silane bonding agent (Clearfil Porcelain Bond). The enamel surfaces were etched with 40% phosphoric acid, rinsed with water, and primed with a two-liquid bonding agent (Clearfil New Bond) that contained a hydrophobic phosphate (10-methacryloyloxydecyl dihydrogen phosphate; MDP). The restorations were bonded with a dual-activated luting composite (Clapearl DC). The veneers have been functioning satisfactorily for an observation period of one year. Combined use of the Clearfil bonding agents and Clapearl DC luting composite is an alternative to conventional materials for seating porcelain laminate veneer restorations, although the system is inapplicable to dentin bonding.

  11. Fabrication of nanoparticle-containing films and nano layers for alloying and joining

    OpenAIRE

    Leifert, Annika; Mondin, Giovanni; Doerfler, Susanne; Hampel, Silke; Kaskel, Stefan; Hofmann, Evelyn; Zschetzsche, Jörg; Pflug, Erik; Dietrich, Georg; Rühl, Maximilian; Braun, Stefan; Schädlich, Stefan

    2014-01-01

    Nanoparticles (NPs) can improve mechanical properties of construction elements. However, the integration is not trivial due to the nanoscopic nature of the particles and the different material properties of particle and device: new processing routes have to be found for homogeneous incorporation. Therefore, a wet chemical synthesis is established to incorporate various ceramic NPs such as TiO2, TiC, SiC, and WC in copper films in desired concentrations. Depending on the kind and concentration...

  12. CHALCO and Guangxi Government Joined Forces to Drive Forward Optimization and Upgrading of Rare Earth Industry

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>In early June, Ding Haiyan, Assistant to General Manager of CHALCO and President of China Rare Metals And Rare Earth Corporation, met with Yang Daoxi, Vice Chairman of the People’s Congress of Guangxi Zhuang Autonomous Region in Nanning, and exchanged views on further development of Guangxi rare

  13. Mechanical strength and analysis of fracture of titanium joining submitted to laser and tig welding

    Directory of Open Access Journals (Sweden)

    Ana Cláudia Gabrielli Piveta

    2012-12-01

    Full Text Available This study compared the tensile strength and fracture mechanism of tungsten inert gas (TIG welds in cylindrical rods of commercially pure titanium (cp Ti with those of laser welds and intact samples. Thirty dumbbell-shaped samples were developed by using brass rods as patterns. The samples were invested in casings, subjected to thermal cycles, and positioned in a plasma arc welding machine under argon atmosphere and vacuum, and titanium was injected under vacuum/pressure. The samples were X-rayed to detect possible welding flaws and randomly assigned to three groups to test the tensile strength and the fracture mechanism: intact, laser welding, and TIG welding. The tensile test results were investigated using ANOVA, which indicated that the samples were statistically similar. The fracture analysis showed that the cpTi samples subjected to laser welding exhibited brittle fracture and those subjected to TIG welding exhibited mixed brittle/ductile fracture with a predominance of ductile fracture with the presence of microcavities and cleavage areas. Intact samples presented the characteristic straightening in the fracture areas, indicating the ductility of the material.

  14. Theoretical study of the interplay between lithium bond and hydrogen bond in complexes involved with HLi and HCN.

    Science.gov (United States)

    Li, Qingzhong; Hu, Ting; An, Xiulin; Li, Wenzuo; Cheng, Jianbo; Gong, Baoan; Sun, Jiazhong

    2009-12-21

    The lithium- and hydrogen-bonded complex of HLi-NCH-NCH is studied with ab initio calculations. The optimized structure, vibrational frequencies, and binding energy are calculated at the MP2 level with 6-311++G(2d,2p) basis set. The interplay between lithium bonding and hydrogen bonding in the complex is investigated with these properties. The effect of lithium bonding on the properties of hydrogen bonding is larger than that of hydrogen bonding on the properties of lithium bonding. In the trimer, the binding energies are increased by about 19% and 61% for the lithium and hydrogen bonds, respectively. A big cooperative energy (-5.50 kcal mol(-1)) is observed in the complex. Both the charge transfer and induction effect due to the electrostatic interaction are responsible for the cooperativity in the trimer. The effect of HCN chain length on the lithium bonding has been considered. The natural bond orbital and atoms in molecules analyses indicate that the electrostatic force plays a main role in the lithium bonding. A many-body interaction analysis has also been performed for HLi-(NCH)(N) (N=2-5) systems.

  15. A Virtual Dig--Joining Archaeology and Fiction to Promote Critical and Historical Thinking

    Science.gov (United States)

    Cooper, David

    2003-01-01

    In this article, the author describes "Dr. Gesundheit and the Mysteries of Snake Valley," a mini-unit that he designed so that his middle-level students could learn to interpret archaeological diagrams, work cooperatively to discover relationships among their observations, and draw well-founded conclusions. The unit requires approximately four…

  16. Joining and reinforcing a composite bumper beam and a composite crush can for a vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Elisabeth; Decker, Leland; Armstrong, Dale; Truskin, James; Pasupuleti, Praveen; Dwarmpudi, Ramesh; Doroudian, Mark

    2017-03-21

    A front bumper beam and crush can (FBCC) system is provided for a vehicle. A bumper beam has an interior surface with a plurality of ribs extending therefrom. The ribs and the interior surface are made of a chopped fiber composite and cooperate to engage a crush can. The chopped fiber composite reinforces the engaging surfaces of the crush can and the interior surface of the bumper beam. The crush can has a tubular body made of a continuous fiber composite. The crush can has outwardly-extending flanges at an end spaced away from the bumper beam. The flanges are at least partially provided with a layer of chopped fiber composite to reinforce a joint between the outwardly-extending flange and the vehicle frame.

  17. Why Women Join the Military: Enlistment Decisions and Postdeployment Experiences of Service Members and Veterans.

    Science.gov (United States)

    Mankowski, Mariann; Tower, Leslie E; Brandt, Cynthia A; Mattocks, Kristin

    2015-10-01

    Over the past three decades women's enlistment has continued to increase. In an effort to help social workers better meet the needs of female veterans, this study sought to learn women's enlistment motivations and postdeployment experiences. This qualitative study was nested within the Women Veterans Cohort Study. Using a semistructured interview guide, authors interviewed 18 enlisted female service members and veterans. The themes that emerged, based on grounded theory, included not only opportunity and calling, but also outcomes. Unexpectedly, enlistment resulted in a professional military career, with over half of the participants making the military their life's work. Further study on the motivation, retention, and the reintegration needs of women postmilitary is necessary, particularly with military recruitment targets of 20 percent women by the year 2020 and the increased awareness of the military as a potentially hostile work environment for women.

  18. Bonding, Achievement, and Activities: School Bonding, Academic Achievement, and Participation in Extracurricular Activities

    Science.gov (United States)

    Howard, Anissa K.; Ziomek-Daigle, Jolie

    2009-01-01

    Utilizing a single-group interrupted time series design (Creswell, 2003), this pilot study examined the relationship between academic achievement, school bonding, and the extracurricular activity participation of "uninvolved" students (n=11) who participated in a voluntary support group at a suburban high school in the southeast. Results…

  19. Bond strength and durability of glass ionomer cements used as bonding agents in the placement of orthodontic brackets.

    Science.gov (United States)

    Klockowski, R; Davis, E L; Joynt, R B; Wieczkowski, G; MacDonald, A

    1989-07-01

    One potential risk of orthodontic treatment is the development of surface decalcification in association with use of brackets and bands. A bonding agent that could render tooth structure more resistant to the caries process clearly would reduce the negative iatrogenic outcomes of orthodontic therapy and thereby benefit the patient. Glass ionomer cement (GIC) bonds chemically to both enamel and dentin. In addition its high fluoride content makes enamel more resistant to caries. The purpose of this study was to evaluate the bond strength and durability of GIC when used as a bonding agent in the placement of orthodontic brackets. The materials tested were three GICs (Ketac-Fil, Ketac-Cem, and Chelon) and a standard bonding agent currently in widespread use (Rely-A-Bond). Brackets were attached to the facial surface of 96 premolar specimens and half the specimens for each bonding agent were thermocycled. Bond shear strength was determined with an Instron testing device by applying a load to the occlusal margin of each bracket to the point of failure. A two-way ANOVA indicated a significant bonding agent by thermocycling interaction (F = 4.78, p less than 0.01). Thermocycling decreased bond strength significantly for all materials, but had the greatest impact on Rely-A-Bond. However, Rely-A-Bond provided the strongest bond with and without thermocycling. Although bond strength for the standard orthodontic bonding agent deteriorates significantly under thermal stress, these results suggest that it is still greater than the bond strength provided by GIC materials.

  20. TESOL and Early Childhood Collaborative Inquiry: Joining Forces and Crossing Boundaries

    Science.gov (United States)

    Baecher, Laura; Jewkes, Abigail M.

    2014-01-01

    Preparing early childhood educators to support effective instruction of English language learners (ELLs) is an important dimension of teacher preparation programs, yet often difficult to enact. This article reports on a collaboration between early childhood education (ECE) faculty and teachers of English to speakers of other languages (TESOL)…

  1. Healthcare hath no fury. Power of religion and might of physicians join forces to prevent joint venture of faith-based Baptist Health, for-profit Triad Hospitals.

    Science.gov (United States)

    Romano, Michael

    2003-07-21

    The power of religion and the might of physicians seem to have joined forces against Baptist Health System's proposed merger with for-profit Triad Hospitals. Doctors and employees of Baptist facilities such as Montclair Baptist Medical Center, left, demanded that the system remain faith-based and under local control.

  2. Accounting for the differences in the structures and relative energies of the highly homoatomic np pi-np pi (n > or = 3)-bonded S2I4 2+, the Se-I pi-bonded Se2I4 2+, and their higher-energy isomers by AIM, MO, NBO, and VB methodologies.

    Science.gov (United States)

    Brownridge, Scott; Crawford, Margaret-Jane; Du, Hongbin; Harcourt, Richard D; Knapp, Carsten; Laitinen, Risto S; Passmore, Jack; Rautiainen, J Mikko; Suontamo, Reijo J; Valkonen, Jussi

    2007-02-05

    The bonding in the highly homoatomic np pi-np pi (n > or = 3)-bonded S2I42+ (three sigma + two pi bonds), the Se-I pi-bonded Se2I42+ (four sigma + one pi bonds), and their higher-energy isomers have been studied using modern DFT and ab initio calculations and theoretical analysis methods: atoms in molecules (AIM), molecular orbital (MO), natural bond orbital (NBO), and valence bond (VB) analyses, giving their relative energies, theoretical bond orders, and atomic charges. The aim of this work was to seek theory-based answers to four main questions: (1) Are the previously proposed simple pi*-pi* bonding models valid for S2I42+ and Se2I42+? (2) What accounts for the difference in the structures of S2I42+ and Se2I42+? (3) Why are the classically bonded isolobal P2I4 and As2I4 structures not adopted? (4) Is the high experimentally observed S-S bond order supported by theoretical bond orders, and how does it relate to high bond orders between other heavier main group elements? The AIM analysis confirmed the high bond orders and established that the weak bonds observed in S2I42+ and Se2I42+ are real and the bonding in these cations is covalent in nature. The full MO analysis confirmed that S2I42+ contains three sigma and two pi bonds, that the positive charge is essentially equally distributed over all atoms, that the bonding between S2 and two I2+ units in S2I42+ is best described by two mutually perpendicular 4c2e pi*-pi* bonds, and that in Se2I42+, two SeI2+ moieties are joined by a 6c2e pi*-pi* bond, both in agreement with previously suggested models. The VB treatment provided a complementary approach to MO analysis and provided insight how the formation of the weak bonds affects the other bonds. The NBO analysis and the calculated AIM charges showed that the minimization of the electrostatic repulsion between EI2+ units (E = S, Se) and the delocalization of the positive charge are the main factors that explain why the nonclassical structures are favored for S2I42

  3. Thioamides: versatile bonds to induce directional and cooperative hydrogen bonding in supramolecular polymers.

    Science.gov (United States)

    Mes, Tristan; Cantekin, Seda; Balkenende, Dirk W R; Frissen, Martijn M M; Gillissen, Martijn A J; De Waal, Bas F M; Voets, Ilja K; Meijer, E W; Palmans, Anja R A

    2013-06-24

    The amide bond is a versatile functional group and its directional hydrogen-bonding capabilities are widely applied in, for example, supramolecular chemistry. The potential of the thioamide bond, in contrast, is virtually unexplored as a structuring moiety in hydrogen-bonding-based self-assembling systems. We report herein the synthesis and characterisation of a new self-assembling motif comprising thioamides to induce directional hydrogen bonding. N,N',N''-Trialkylbenzene-1,3,5-tris(carbothioamide)s (thioBTAs) with either achiral or chiral side-chains have been readily obtained by treating their amide-based precursors with P2S5. The thioBTAs showed thermotropic liquid crystalline behaviour and a columnar mesophase was assigned. IR spectroscopy revealed that strong, three-fold, intermolecular hydrogen-bonding interactions stabilise the columnar structures. In apolar alkane solutions, thioBTAs self-assemble into one-dimensional, helical supramolecular polymers stabilised by three-fold hydrogen bonding. Concentration- and temperature-dependent self-assembly studies performed by using a combination of UV and CD spectroscopy demonstrated a cooperative supramolecular polymerisation mechanism and a strong amplification of supramolecular chirality. The high dipole moment of the thioamide bond in combination with the anisotropic shape of the resulting cylindrical aggregate gives rise to sufficiently strong depolarised light scattering to enable depolarised dynamic light scattering (DDLS) experiments in dilute alkane solution. The rotational and translational diffusion coefficients, D(trans) and D(rot), were obtained from the DDLS measurements, and the average length, L, and diameter, d, of the thioBTA aggregates were derived (L = 490 nm and d = 3.6 nm). These measured values are in good agreement with the value L(w) = 755 nm obtained from fitting the temperature-dependent CD data by using a recently developed equilibrium model. This experimental verification

  4. Hydrogen bonds in concreto and in computro

    Science.gov (United States)

    Stouten, Pieter F. W.; Kroon, Jan

    1988-07-01

    Molecular dynamics simulations of liquid water and liquid methanol have been carried out. For both liquids an effective pair potential was used. The models were fitted to the heat of vaporization, pressure and various radial distribution functions resulting from diffraction experiments on liquids. In both simulations 216 molecules were put in a cubic periodical ☐. The system was loosely coupled to a temperature bath and to a pressure bath. Following an initial equilibration period relevant data were sampled during 15 ps. The distributions of oxygen—oxygen distances in hydrogen bonds obtained from the two simulations are essentially the same. The distribution obtained from crystal data is somewhat different: the maximum has about the same position, but the curve is much narrower, which can be expected merely from the fact that diffraction experiments only supply average atomic positions and hence average interatomic distances. When thermal motion is taken into account a closer likeness is observed.

  5. Bonding, structure and solid-state chemistry

    CERN Document Server

    Ladd, Mark

    2016-01-01

    This book is aimed at undergraduate students in both chemistry and those degree subjects in which chemistry forms a significant part. It does not reflect any particular academic year, and so finds a place during the normal span of degree studies in the physical sciences. An A-level standard in science and mathematics is presumed; additional mathematical treatments are discussed in Appendices. An introductory first chapter leads into the main subject matter, which is treated through four chapters in terms of the principle bonding forces of cohesion in the solid state; a further chapter discusses nanosize materials. Important applications of the study topics are interspersed at appropriate points within the text. Each chapter is provided with a set of problems of varying degrees of difficulty, so as to assist the reader in gaining a facility with the subject matter and its applications. The problems are supplemented by detailed tutorial solutions, some of which present additional relevant material that indicate...

  6. Joined-Up ICT Innovation in Government: An analysis of the creation of eIDM systems from an Advocacy Coalition and social capital perspective

    NARCIS (Netherlands)

    N.M. Huijboom (Noor)

    2010-01-01

    textabstractThis chapter introduces the subject of this thesis – joined-up ICT innovation in the public sector. The first section demonstrates that scientists and policy makers fully agree that ICT innovation should be a joint effort involving multiple public sector actors. To solve today’s urgent s

  7. Homologous recombination and non-homologous end-joining repair pathways in bovine embryos with different developmental competence

    Energy Technology Data Exchange (ETDEWEB)

    Henrique Barreta, Marcos [Universidade Federal de Santa Catarina, Campus Universitario de Curitibanos, Curitibanos, SC (Brazil); Laboratorio de Biotecnologia e Reproducao Animal-BioRep, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Garziera Gasperin, Bernardo; Braga Rissi, Vitor; Cesaro, Matheus Pedrotti de [Laboratorio de Biotecnologia e Reproducao Animal-BioRep, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Ferreira, Rogerio [Centro de Educacao Superior do Oeste-Universidade do Estado de Santa Catarina, Chapeco, SC (Brazil); Oliveira, Joao Francisco de; Goncalves, Paulo Bayard Dias [Laboratorio de Biotecnologia e Reproducao Animal-BioRep, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Bordignon, Vilceu, E-mail: vilceu.bordignon@mcgill.ca [Department of Animal Science, McGill University, Ste-Anne-De-Bellevue, QC (Canada)

    2012-10-01

    This study investigated the expression of genes controlling homologous recombination (HR), and non-homologous end-joining (NHEJ) DNA-repair pathways in bovine embryos of different developmental potential. It also evaluated whether bovine embryos can respond to DNA double-strand breaks (DSBs) induced with ultraviolet irradiation by regulating expression of genes involved in HR and NHEJ repair pathways. Embryos with high, intermediate or low developmental competence were selected based on the cleavage time after in vitro insemination and were removed from in vitro culture before (36 h), during (72 h) and after (96 h) the expected period of embryonic genome activation. All studied genes were expressed before, during and after the genome activation period regardless the developmental competence of the embryos. Higher mRNA expression of 53BP1 and RAD52 was found before genome activation in embryos with low developmental competence. Expression of 53BP1, RAD51 and KU70 was downregulated at 72 h and upregulated at 168 h post-insemination in response to DSBs induced by ultraviolet irradiation. In conclusion, important genes controlling HR and NHEJ DNA-repair pathways are expressed in bovine embryos, however genes participating in these pathways are only regulated after the period of embryo genome activation in response to ultraviolet-induced DSBs.

  8. Joining time-resolved thermometry and magnetic-induced heating in a single nanoparticle unveils intriguing thermal properties.

    Science.gov (United States)

    Piñol, Rafael; Brites, Carlos D S; Bustamante, Rodney; Martínez, Abelardo; Silva, Nuno J O; Murillo, José L; Cases, Rafael; Carrey, Julian; Estepa, Carlos; Sosa, Cecilia; Palacio, Fernando; Carlos, Luís D; Millán, Angel

    2015-03-24

    Whereas efficient and sensitive nanoheaters and nanothermometers are demanding tools in modern bio- and nanomedicine, joining both features in a single nanoparticle still remains a real challenge, despite the recent progress achieved, most of it within the last year. Here we demonstrate a successful realization of this challenge. The heating is magnetically induced, the temperature readout is optical, and the ratiometric thermometric probes are dual-emissive Eu(3+)/Tb(3+) lanthanide complexes. The low thermometer heat capacitance (0.021·K(-1)) and heater/thermometer resistance (1 K·W(-1)), the high temperature sensitivity (5.8%·K(-1) at 296 K) and uncertainty (0.5 K), the physiological working temperature range (295-315 K), the readout reproducibility (>99.5%), and the fast time response (0.250 s) make the heater/thermometer nanoplatform proposed here unique. Cells were incubated with the nanoparticles, and fluorescence microscopy permits the mapping of the intracellular local temperature using the pixel-by-pixel ratio of the Eu(3+)/Tb(3+) intensities. Time-resolved thermometry under an ac magnetic field evidences the failure of using macroscopic thermal parameters to describe heat diffusion at the nanoscale.

  9. Development of Be/Glidcop joint obtained by hot isostatic pressing diffusion bonding for high in-service temperature

    Energy Technology Data Exchange (ETDEWEB)

    Saint-Antonin, F.; Bucci, P.; Burlet, H.; Le Marois, G. [CEA Centre d`Etudes de Grenoble, 38 (France); Barberi, D.; Laille, A.

    1998-01-01

    This paper addresses some aspects of the beryllium-Glidcop joining by Hot Isostatic Pressing diffusion Bonding. The quality of a joint is mainly dependent on the interface microstructure. Thus, as Be/copper direct bonding is not recommended, the choice of interlayers is a critical point. The joining process parameters, i.e. temperature, pressure and time, must take into account the in-service requirements, the mechanical and metallurgical properties of each material. The Be/Glidcop joining process developed at CEA/Grenoble is presented here. (author)

  10. Agrobacterium tumefaciens T-DNA Integration and Gene Targeting in Arabidopsis thaliana Non-Homologous End-Joining Mutants

    Directory of Open Access Journals (Sweden)

    Qi Jia

    2012-01-01

    Full Text Available In order to study the role of AtKu70 and AtKu80 in Agrobacterium-mediated transformation and gene targeting, plant lines with a T-DNA insertion in AtKu80 or AtKu70 genes were functionally characterized. Such plant lines lacked both subunits, indicating that heterodimer formation between AtKu70 and AtKu80 is needed for the stability of the proteins. Homozygous mutants were phenotypically indistinguishable from wild-type plants and were fertile. However, they were hypersensitive to the genotoxic agent bleomycin, resulting in more DSBs as quantified in comet assays. They had lower end-joining efficiency, suggesting that NHEJ is a critical pathway for DSB repair in plants. Both Atku mutants and a previously isolated Atmre11 mutant were impaired in Agrobacterium T-DNA integration via floral dip transformation, indicating that AtKu70, AtKu80, and AtMre11 play an important role in T-DNA integration in Arabidopsis. The frequency of gene targeting was not significantly increased in the Atku80 and Atku70 mutants, but it was increased at least 10-fold in the Atmre11 mutant compared with the wild type.

  11. Biochemical Kinetics Model of DSB Repair and GammaH2AX FOCI by Non-homologous End Joining

    Science.gov (United States)

    Cucinotta, Francis, A.; Pluth, Janice M.; Anderson, Jennifer A.; Harper, Jane V.; O'Neill, Peter

    2007-01-01

    We developed a biochemical kinetics approach to describe the repair of double strand breaks (DSB) produced by low LET radiation by modeling molecular events associated with the mechanisms of non-homologous end-joining (NHEJ). A system of coupled non-linear ordinary differential equations describes the induction of DSB and activation pathways for major NHEJ components including Ku(sub 70/80), DNA-PK(sub cs), and the Ligase IV-XRCC4 hetero-dimer. The autophosphorylation of DNA-PK(sub cs and subsequent induction of gamma-H2AX foci observed after ionizing radiation exposure were modeled. A two-step model of DNA-PK(sub cs) regulation of repair was developed with the initial step allowing access of other NHEJ components to breaks, and a second step limiting access to Ligase IV-XRCC4. Our model assumes that the transition from the first to second-step depends on DSB complexity, with a much slower-rate for complex DSB. The model faithfully reproduced several experimental data sets, including DSB rejoining as measured by pulsed-field electrophoresis (PFGE), quantification of the induction of gamma-H2AX foci, and live cell imaging of the induction of Ku(sub 70/80). Predictions are made for the behaviors of NHEJ components at low doses and dose-rates, where a steady-state is found at dose-rates of 0.1 Gy/hr or lower.

  12. Bond Properties and Experimental Methods of Textile Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Textile reinforced concrete(TRC, for short) allows the low size production and offers a high effectiveness of the reinforcement by using continuous roving instead of short-chopped fibers. However, whether textiles can cooperate with concrete very well depends on the bond between them. In this paper, the bonding mechanism that the stress was transferred from fine concrete to textile was analyzed, and the influences of the initial bond length of textile, the surface treatment of textile, the strength and workability of concrete as well as the level of prestressing force on bond behavior were investigated on the basis of pull-out tests. The results reveal that with initial bond length increasing, the maximum pull force increases, and increasing concrete strength and improving workability of concrete matrix, epoxy resin impregnating and sand covering of textile as well as prestressing textile can obviously increase the bond strength between the textile and concrete.

  13. 27 CFR 19.241 - Operations bond-distilled spirits plant and adjacent bonded wine cellar.

    Science.gov (United States)

    2010-04-01

    ... spirits plant and adjacent bonded wine cellar. 19.241 Section 19.241 Alcohol, Tobacco Products and... wine cellar. (a) General. A wine cellar under the provisions of 27 CFR part 24 shall be treated as... subpart G for the production of distilled spirits; and (2) Such wine cellar and distilled spirits...

  14. Ectopic expression of RNF168 and 53BP1 increases mutagenic but not physiological non-homologous end joining.

    Science.gov (United States)

    Zong, Dali; Callén, Elsa; Pegoraro, Gianluca; Lukas, Claudia; Lukas, Jiri; Nussenzweig, André

    2015-05-26

    DNA double strand breaks (DSBs) formed during S phase are preferentially repaired by homologous recombination (HR), whereas G1 DSBs, such as those occurring during immunoglobulin class switch recombination (CSR), are repaired by non-homologous end joining (NHEJ). The DNA damage response proteins 53BP1 and BRCA1 regulate the balance between NHEJ and HR. 53BP1 promotes CSR in part by mediating synapsis of distal DNA ends, and in addition, inhibits 5' end resection. BRCA1 antagonizes 53BP1 dependent DNA end-blocking activity during S phase, which would otherwise promote mutagenic NHEJ and genome instability. Recently, it was shown that supra-physiological levels of the E3 ubiquitin ligase RNF168 results in the hyper-accumulation of 53BP1/BRCA1 which accelerates DSB repair. Here, we ask whether increased expression of RNF168 or 53BP1 impacts physiological versus mutagenic NHEJ. We find that the anti-resection activities of 53BP1 are rate-limiting for mutagenic NHEJ but not for physiological CSR. As heterogeneity in the expression of RNF168 and 53BP1 is found in human tumors, our results suggest that deregulation of the RNF168/53BP1 pathway could alter the chemosensitivity of BRCA1 deficient tumors.

  15. Shear Bond Strength of Two Types of Glass Ionomer to Bleached Dentin: Effect of Delayed Bonding and Antioxidant Agent

    Science.gov (United States)

    Omrani, Ladan Ranjbar; Sabouri, Parastoo; Abbasi, Mehdi; Ahmadi, Elham; Ghavam, Maryam

    2016-01-01

    Background: Studies have shown a reduction in bond strength of composites and glass ionomer to bleached enamel and dentin. Several methods have been proposed to reverse compromised bond strength. Objective: The aim of this study was to evaluate the effect of delayed bonding and application of antioxidant agent on the bond strength of reinforced self-cured (Fuji IX) and light-cured glass ionomers (Fuji II LC) to bleached dentin. Material: Eighty extracted third molars were randomly divided into 8 groups. Buccal dentin surfaces received different treatments: Two control groups: no treatment + bonding Fuji IX or Fuji II LC. Two immediate bonding groups: bleaching + bonding Fuji IX or Fuji II LC. Two delayed bonding groups: bleaching + 7 days delay + bonding Fuji IX or Fuji II LC. Two sodium ascorbate application groups: Bleaching + application of 10% sodium ascorbate + bonding Fuji IX or Fuji II LC. All samples were tested for shear bond strength. Two-way analysis of variance (ANOVA) was used to compare the mean and standard deviations among groups, followed by the Tukey’s test for significant interaction. Results: No statistically significant difference was detected in shear bond strength of Fuji IX to bleached or normal dentin. Although a significant reduction was found shear bond strength values of Fuji II LC to bleached dentin, no significant difference was observed between no bleaching group and those treated with 10% sodium ascorbate or 7 days of delay in bonding for both types of glass ionomer. Conclusion: Bleaching had no significant effect on shear bond strength of Fuji IX to dentin; this type of GI can be used immediately after bleaching. PMID:28217187

  16. Laser Surface Preparation and Bonding of Aerospace Structural Composites

    Science.gov (United States)

    Belcher, M. A.; Wohl, C. J.; Hopkins, J. W.; Connell, J. W.

    2010-01-01

    Adhesive bonds are critical to the integrity of built-up structures. Disbonds can often be detected but the strength of adhesion between surfaces in contact is not obtainable without destructive testing. Typically the number one problem in a bonded structure is surface contamination, and by extension, surface preparation. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, are not ideal because of variations in their application. Etching of carbon fiber reinforced plastic (CFRP) panels using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser appears to be a highly precise and promising way to both clean a composite surface prior to bonding and provide a bond-promoting patterned surface akin to peel ply without the inherent drawbacks from the same (i.e., debris and curvature). CFRP surfaces prepared using laser patterns conducive to adhesive bonding were compared to typical prebonding surface treatments through optical microscopy, contact angle goniometry, and post-bonding mechanical testing.

  17. THE POSITION OF THE RUSSIAN FEDERATION AND FEDERAL REPUBLIC OF GERMANY ON THE BALTIC REPUBLICS’ (LATVIA, LITHUANIA, ESTONIA JOINING THE EUROPEAN UNION

    Directory of Open Access Journals (Sweden)

    Mariya Dmitrievna Portnyagina

    2013-10-01

    Full Text Available Enlargement of the EU in 2004 was of great significance not only for the EU members, but for the Russian Federation as the candidates were former USSR republics and countries that had been under the influence of the USSR.  The purpose of this article is to uncover the attitude of Russian and German officials to Latvia, Lithuania and Estonia’s joining the EU. The study uses the methods of historicism and objectivity as its basis. A regional approach that describes the development of the region into global political process is used.The author proves that Russia has underestimated the consequence of Latvia, Lithuania and Estonia’s joining the EU. The Russian Federation made the hasty judgement that the Baltic countries’ joining the EU would automatically solve the bilateral problems in relations between Russia, Latvia, Lithiania and Estonia. Russian politicians failed to detect negative economic consequences, which the Baltic states’ joining the European Union brought about. The position of the German government was ambiguous. It was impacted by the obligations within its role as the ‘motor’ of European integration, but also had to consider the direct interests of the Federal Republic of Germany.  The German ruling coalition by morally supporting the intention of the Baltic Republics to join the EU delegated the role of an ‘advocate’ of newly independent republics to the northern European countries while taking the right to defend primarily national interests of the Federal Republic of Germany.The materials of the study can be used for further research of the history of the Baltic Region, in lectures and special courses.DOI: http://dx.doi.org/10.12731/2218-7405-2013-7-32

  18. The Pricing and Efficiency of Australian Treasury Bond Futures

    Directory of Open Access Journals (Sweden)

    Alex Frino

    2014-06-01

    Full Text Available This paper examines the efficiency of the Treasury Bond futures market in Australia. We provide a comprehensive explanation of the method used to price, and evaluate efficiency of the 3 and 10 Year Australian Treasury Bond Futures contracts, against underlying bond baskets. Results indicate that the futures contracts exhibit minimal variation from their theoretical value. The average mispricing equates to 1.96 basis points for 3 Year and 1.19 basis points for 10 Year government bond futures contracts. However, during some periods (including the financial crisis of 2008, the bond futures contracts exhibit greater mispricing. Consistent with prior literature, we find a decreasing pattern of mispricing towards expiry, with the futures contract yields and average forward yields of the underlying bonds converging towards expiry. Further analysis reveals that volatility and time to expiry exhibit a significant positive relationship with the absolute level of mispricing.

  19. Transient liquid phase bonding of titanium-, iron- and nickel-based alloys

    Science.gov (United States)

    Rahman, A. H. M. Esfakur

    The operating temperature of land-based gas turbines and jet engines are ever-increasing to increase the efficiency, decrease the emissions and minimize the cost. Within the engines, complex-shaped parts experience extreme temperature, fatigue and corrosion conditions. Ti-based, Ni-based and Fe-based alloys are commonly used in gas turbines and jet engines depending on the temperatures of different sections. Although those alloys have superior mechanical, high temperature and corrosion properties, severe operating conditions cause fast degradation and failure of the components. Repair of these components could reduce lifecycle costs. Unfortunately, conventional fusion welding is not very attractive, because Ti reacts very easily with oxygen and nitrogen at high temperatures, Ni-based superalloys show heat affected zone (HAZ) cracking, and stainless steels show intergranular corrosion and knife-line attack. On the other hand, transient liquid phase (TLP) bonding method has been considered as preferred joining method for those types of alloys. During the initial phase of the current work commercially pure Ti, Fe and Ni were diffusion bonded using commercially available interlayer materials. Commercially pure Ti (Ti-grade 2) has been diffusion bonded using silver and copper interlayers and without any interlayer. With a silver (Ag) interlayer, different intermetallics (AgTi, AgTi2) appeared in the joint centerline microstructure. While with a Cu interlayer eutectic mixtures and Ti-Cu solid solutions appeared in the joint centerline. The maximum tensile strengths achieved were 160 MPa, 502 MPa, and 382 MPa when Ag, Cu and no interlayers were used, respectively. Commercially pure Fe (cp-Fe) was diffusion bonded using Cu (25 m) and Au-12Ge eutectic interlayer (100 microm). Cu diffused predominantly along austenite grain boundaries in all bonding conditions. Residual interlayers appeared at lower bonding temperature and time, however, voids were observed in the joint

  20. Ultrasonic Additive Manufacturing: Weld Optimization for Aluminum 6061, Development of Scarf Joints for Aluminum Sheet Metal, and Joining of High Strength Metals

    Science.gov (United States)

    Wolcott, Paul J.

    that plastic deformation occurs in the bulk of the foil, while previous studies have only identified microstructural changes to the bond interface region. A methodology for joining aluminum 6061 sheet material 0.076 in. (1.93 mm) thick is proposed based on iterative design studies which identified a scarf joint configuration as viable. Design of experiments studies indicate optimal properties can be achieved using a scarf joint angle of 10SO. Room temperature and elevated temperature tensile, and room temperature fatigue testing exhibit joint mechanical properties similar to solid, homogeneous material. Successful joints were achieved for Al/Ti, aluminum to steel, steel to aluminum, and steel to steel combinations. Mechanical characterization studies of Al/Ti combinations indicate that post-process heat treatments can significantly increase mechanical properties. Microstructural evaluations including electron back scatter diffraction show significant deformation within the softer aluminum layers. Investigations of Al/steel combinations indicate that mostly voidless interfaces occur and that plastic deformation is present in the steel layers only. Steel to steel combinations, while proven possible, require further work to enhance the consistency of the joints and improve the ability to build larger structures.

  1. The Romanian Municipal Bond Market and the International Financial Crisis

    Directory of Open Access Journals (Sweden)

    VALENTINA VASILE

    2010-06-01

    Full Text Available In Romania, the bond market was set up later, comparatively to the equity market. This market is in a development process, but the international financial crisis has affected even the interest of investors in bonds. The secondary municipal bond market is not a very liquid market because these securities are bought from the primary market and held in portfolios by investors because these bonds have a low risk. The issue of these bonds is correlated with the financial independence and the level of decentralization of the local public authorities. The issuance of these bonds is correlated with financial independence and decentralization level specific to local public authorities. Under crisis conditions, the volatility of this market is more significant, the increasing deficits of local budgets decreasing the interest of the middle-class in investing in such financial instruments.

  2. New Product Development. Engineering and Commerce Students Join Forces with a Corporate Sponsor.

    Science.gov (United States)

    Audet, Josee; Pegna, Joseph

    2001-01-01

    Mechanical engineering and business student teams developed new products using a corporate sponsor's technology in a simulated business setting. Students learned about product development and venture start-up, and the sponsor gained new applications for its patented technology. (SK)

  3. Nonhomologous end joining and homologous recombination DNA repair pathways in integration mutagenesis in the xylose-fermenting yeast Pichia stipitis.

    Science.gov (United States)

    Maassen, Nicole; Freese, Stefan; Schruff, Barbara; Passoth, Volkmar; Klinner, Ulrich

    2008-08-01

    Pichia stipitis integrates linear homologous DNA fragments mainly ectopically. High rates of randomly occurring integration allow tagging mutagenesis with high efficiency using simply PCR amplificates of suitable selection markers from the P. stipitis genome. Linearization of an autonomously replicating vector caused a distinct increase of the transformation efficiency compared with the circular molecule. Cotransformation of a restriction endonuclease further enhanced the transformation efficiency. This effect was also observed with integrative vector DNA. In most cases vector integration in chromosomal targets did not depend on microhomologies, indicating that restriction-enzyme-mediated integration (REMI) does not play an essential role in P. stipitis. Small deletions were observed at the ends of the integrated vectors and in the target sites. Disruption of the PsKU80 gene increased the frequency of homologous integration considerably but resulted in a remarkable decrease of the transformation efficiency. These results suggest that in P. stipitis the nonhomologous end joining (NHEJ) pathway obviously predominates the homologous recombination pathway of double-strand break repair.

  4. Interfiber bonding and fiber segment activation in paper

    Directory of Open Access Journals (Sweden)

    Hannu Paulapuro

    2007-01-01

    Full Text Available Bonding and activation in paper were studied with the help of laboratory test sheets and common paper strength tests. Different papermaking furnishes and raw material treatments were used to examine the effects they have on bonding and activation. Furthermore, various boundary conditions during drying were included to single out the influence of bonding and activation on paper properties. It was found that bonding is clearly increased by beating of kraft pulp, starch addition, and thermomechanical pulp fines, whereas activation benefited most from beating and addition of reinforcement fibers to mechanical pulp based furnishes. Subjecting test sheets to increasing amounts of drying stress affected activation positively, and bonding negatively. The increase in activation did not seem to be dependent on the beating degree of chemical pulp fibers. Bonding, on the other hand, deteriorated more significantly in sheets made of extensively beaten kraft fibers, i.e. in sheets where the initial bonding potential was higher. Commonly used paper strength measurements provide dependable and accurate tools for assessing the effect of different variables on both bonding and activation. A short literature survey of bonding and activation is also provided.

  5. Sinopec and CNPC Join Hands to Keep Domestic oil Market Stable

    Institute of Scientific and Technical Information of China (English)

    Yang Xiangfeng

    2003-01-01

    @@ Sinopec and CNPC have recently issued an urgent circular on the joint efforts to stabilize the country's oil products market. The State Development and Reform Committee has lowered the retail median prices of gasoline and diesel by 290 yuan per ton and 260 yuan per ton respectively.

  6. Who Is Joining Physics and Why? Factors Influencing the Choice of Physics among Ethiopian University Students

    Science.gov (United States)

    Semela, Tesfaye

    2010-01-01

    This paper investigates the enrolment trends and the critical factors that impinge on students' choice of physics as major field of study. The data were generated from primary and secondary sources. Primary data was acquired based on a semi-structured interview with 14 sophomore and 11 senior students and five instructors of the department of…

  7. The Comparative Analysis of Grain Trade Policies between China and South Korean after Joining the WTO

    Institute of Scientific and Technical Information of China (English)

    Li Xiaomei

    2006-01-01

    @@ In view of different grain trade structure and protectionism period, it is well known that China difficultly uses the technology and the green barriers to protect her domestic market as same skilled as Japan and European Union. At the same time, China often encounters above two barriers when it exports Japan and European Union.

  8. Domestic violence and children: the case for joined-up working.

    Science.gov (United States)

    Sully, Philippa

    2008-01-01

    Domestic violence causes injury and death throughout the world. Women are most likely to be the victims. In the United Kingdom (UK) two women die each week and 30 men each year as a result of this multifaceted and common source of violent crime. It is a sign that children are at risk of abuse too, as they can be directly or indirectly caught up in the violence. A central tenet of domestic violence is power dynamics: the need for the abuser to control their partner and at times the children. Domestic violence is a health care as well as a social, ethical and legal issue. This paper emphasises the importance of professional practitioners being aware of the signs and symptoms of abuse, its frequency, the risk factors for homicide from domestic violence, and the risks to children and the impact on them. It is likely that the violence is known about in the community and by professional practitioners. The paper explores the role of practitioners and how important it is for them to examine their own values and beliefs about domestic violence. It is imperative for responses to be interprofessional and interagency if practitioners are to meet the needs of survivors and their families and work in partnership with them. Fundamental to this approach is effective information sharing and the sensitive co-ordination of services for survivors. It is no longer acceptable to regard domestic violence, a cause of misery and loss of life, as a private matter and not to consider it as a health care or human rights issue. Clients and their families have a right to sensitive inquiry about their situations and the offer of services to themselves and their children.

  9. Hydrogen and Dihydrogen Bonds in the Reactions of Metal Hydrides.

    Science.gov (United States)

    Belkova, Natalia V; Epstein, Lina M; Filippov, Oleg A; Shubina, Elena S

    2016-08-10

    The dihydrogen bond-an interaction between a transition-metal or main-group hydride (M-H) and a protic hydrogen moiety (H-X)-is arguably the most intriguing type of hydrogen bond. It was discovered in the mid-1990s and has been intensively explored since then. Herein, we collate up-to-date experimental and computational studies of the structural, energetic, and spectroscopic parameters and natures of dihydrogen-bonded complexes of the form M-H···H-X, as such species are now known for a wide variety of hydrido compounds. Being a weak interaction, dihydrogen bonding entails the lengthening of the participating bonds as well as their polarization (repolarization) as a result of electron density redistribution. Thus, the formation of a dihydrogen bond allows for the activation of both the MH and XH bonds in one step, facilitating proton transfer and preparing these bonds for further transformations. The implications of dihydrogen bonding in different stoichiometric and catalytic reactions, such as hydrogen exchange, alcoholysis and aminolysis, hydrogen evolution, hydrogenation, and dehydrogenation, are discussed.

  10. Solid cartridge for a pulse weld forming electrode and method of joining tubular members

    Energy Technology Data Exchange (ETDEWEB)

    Bonnen, John Joseph Francis; Golovashchenko, Sergey Fedorovich; Mamutov, Alexander; Maison, Lloyd Douglas; Dawson, Scott Alwyn; deVries, James

    2016-02-23

    A cartridge assembly is disclosed for a pulse welding a first tube supported on a mandrel to a second tube. An outer tool is assembled over the second tube and a stored charge is discharged in the cartridge assembly. The cartridge comprises an annular conductor and a solid casing enveloping the conductor. The stored charge is electrically connected to the conductor and discharged through the conductor to compress the second tube and pulse weld the second tube to the first tube.

  11. Joining the Pieces: Using Concept Maps for Integrated Learning and Assessment in an Introductory Management Course

    Science.gov (United States)

    Connolly, Heather; Spiller, Dorothy

    2016-01-01

    This paper reports on and evaluates the use of concept mapping as a learning tool in a large first year Management course. The goal was to help students make personal sense of course learning and to build their understanding of links and relationships between key course ideas. Concept mapping was used for three summative assessment pieces,…

  12. World Crisis as "Teachable Moment": Joining Global Issues, International Law, and the Internet in the Classroom.

    Science.gov (United States)

    Leary, John E., Jr.

    2000-01-01

    Describes a mock judicial proceeding that incorporated computers in the classroom and questioned international law. Explains that students were divided into interested parties in the Kosovo conflict (NATO members, the Yugoslavian government, Kosovo Albanians, Russians, and Chinese), a delegation of human-rights groups, and a panel of judges. (CMK)

  13. Modeling the joined performance of PanSTARRS1 and PanSTARRS2 telescopes

    Science.gov (United States)

    Lilly (Schunova), Eva; Wainscoat, Richard J.; Weryk, Robert J.

    2016-10-01

    We have performed detailed simulations of the 1st and the 2nd telescope of the Panoramatic Survey Telescope and Rapid response System (PanSTARRS, Morgan et al. 2012, SPIE Conference Series, Vol. 8444; Chambers et al. 2007, Bulletin of the American Astronomical Society, Vol. 39, #142.06) in order to assess their combined performance and to optimize survey strategy for discovery and follow-up observations of near-Earth asteroids (NEAs).PanSTARRS1 (PS1) is situated on the summit of Haleakala, Maui (observatory code F51) and has been operated by the University of Hawaii since the spring of 2010. PS1 has a 1.8 m diameter primary mirror with an ~7 deg2 field of view and can survey ~900 deg2/night for moving objects.PS2 is located adjacent to PS1, and is similar, but benefits from many improvements coming from our experience with PS1. PS2 will be operational very soon.We will show how the best and the worst case scenarios of observing conditions (i.e. regarding the weather and the position of the Galactic plane) affect the NEA detection efficiency during a 1-month long survey for several PS1 and PS2 observing and follow-up strategies.

  14. Highlights from e-EPS: EPS and EuChems are joining forces

    CERN Multimedia

    2013-01-01

    e-EPS News is an addition to the CERN Bulletin line-up, showcasing articles from e-EPS – the European Physical Society newsletter – as part of a collaboration between the two publications.   On the occasion of the EPS Council 2013 in Strasbourg, a memorandum of understanding was signed between the European Association for Chemical and Molecular Societies (EuCheMS) and the European Physical Society (EPS) by presidents Ulrich Schubert and Luisa Cifarelli. EuCheMS and EPS share many objectives, such as community building, scientific excellence, communication and representation of their respective members to European policy makers. The two societies recognise that issues in many fields such as education, publication, support for basic sciences and frontier research are similar in their respective disciplines. They wish to combine efforts in developing and presenting common standpoints to their mutual benefit as European representatives in chemistry ...

  15. Join the Revolution: How Montessori for Aging and Dementia can Change Long-Term Care Culture.

    Science.gov (United States)

    Bourgeois, Michelle S; Brush, Jennifer; Elliot, Gail; Kelly, Anne

    2015-08-01

    Efforts to improve the quality of life of persons with dementia in long-term care through the implementation of various approaches to person-centered care have been underway for the past two decades. Studies have yielded conflicting reports evaluating the evidence for these approaches. The purpose of this article is to outline the findings of several systematic reviews of this literature, highlighting the areas of improvement needs, and to describe a new person-centered care model, DementiAbility Methods: The Montessori Way. This model focuses on the abilities, needs, interests, and strengths of the person and creating worthwhile and meaningful roles, routines, and activities for the person within a supportive physical environment. This is accomplished through gaining the commitment of the facility's leaders, training staff, and monitoring program implementation. The potential for a culture change in long-term care environments is dependent on the development and rigorous evaluation of person-centered care approaches.

  16. Three High-Tech High Seniors Join the Alia Expedition to Samoa: Science and Science Education

    Science.gov (United States)

    English, B.; Delaney, R.; Staudigel, D.; Staudigel, H.; Koppers, A.; Hart, S.

    2005-12-01

    Three high school seniors from High Tech High (HTH) participated in the ALIA expedition that explored the Samoan hot spot track through seafloor mapping, rock sampling and the study of the water column above an active submarine volcano. The primary responsibility of the HTH participants focused on outreach and education, but they also were substantively involved in all scientific aspects of the cruise. Education and outreach activities included: maintaining the cruise website,the creation of ERESE digital library resources for earth science education, live video-conferences with students half a world away in San Diego, and offering tours of the Research Vessel Kilo Moana during an open house event organized with the Samoa Department of Eduation. At this occasion, the HTH seniors shared experiences and knowledge with the visiting Samoan elementary and high school students. Science involvement of the high school seniors included deck and laboratory work, by assisting with dredging, piston coring, rock cataloguing, casting CTDs, and computer programming. Three major computer programming efforts by the HTH seniors substantively supported the outreach activities and the science operations during ALIA. (1) The development of "CustomHTMLExport", a utility that allows for the export of photographs and their metadata into web pages and digital library collection. (2) The "CruiseWatch" featureson the ALIA website (http://earthref.org/ERESE/projects/ALIA/) that displays in near - real time key shipboard data such as the location on a map, geographic coordinates, ship speed, direction and wind speed and dredging data. (3) A dredge location simulator to predict the location of the dredge with respect to the ship and the seafloor which was made necessary for the safety of dredging due to the failure of pingers that normally are used to provide critical data for the location of the dredge with respect to the seafloor. The dredge location model is based a fluid dynamics approach

  17. EMI datalib: Joining the best of ARC and gLite data libraries

    CERN Document Server

    Nilsen, JK; Devresse, A; Molnar, Zs; Nagy, Zs; Salichos, M

    2012-01-01

    To manage data in the grid, with its jungle of protocols and enormous amount of data in different storage solutions, it is important to have a strong, versatile and reliable data management library. While there are several data management tools and libraries available, they all have different strengths and weaknesses, and it can be hard to decide which tool to use for which purpose. EMI is a collaboration between the European middleware providers aiming to take the best out of each middleware to create one consolidated, all-purpose grid middleware. When EMI started there were two main tools for managing data - gLite had lcg util and the GFAL library, ARC had the ARC data tools and libarcdata2. While different in design and purpose, they both have the same goal, to manage data in the grid. The design of the new EMI datalib was ready by the end of 2011, and a first prototype is now implemented and going through a thorough testing phase. This presentation will give the latest results of the consolidated library ...

  18. Dust evolution, a global view I. Nanoparticles, nascence, nitrogen and natural selection … joining the dots

    Science.gov (United States)

    Jones, A. P.

    2016-12-01

    The role and importance of nanoparticles for interstellar chemistry and beyond is explored within the framework of The Heterogeneous dust Evolution Model for Interstellar Solids (THEMIS), focusing on their active surface chemistry, the effects of nitrogen doping and the natural selection of interesting nanoparticle sub-structures. Nanoparticle-driven chemistry, and in particular the role of intrinsic epoxide-type structures, could provide a viable route to the observed gas phase OH in tenuous interstellar clouds en route to becoming molecular clouds. The aromatic-rich moieties present in asphaltenes probably provide a viable model for the structures present within aromatic-rich interstellar carbonaceous grains. The observed doping of such nanoparticle structures with nitrogen, if also prevalent in interstellar dust, could perhaps have important and observable consequences for surface chemistry and the formation of precursor pre-biotic species.

  19. Assembly injection moulding joins metal and thermoplastics; Montagespritzgiessen verbindet Metall und Thermoplast

    Energy Technology Data Exchange (ETDEWEB)

    Drummer, Dietmar; Meister, Steve [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Kunststofftechnik; Reichart, Marc [HBW Gubesch Kunststoff Engineering GmbH, Wilhelmsdorf (Germany)

    2010-03-08

    Automotive safety restraint system components increasingly use flexible styrenic and olefinic TPEs. With continued evolution in automotive interior design and performance requirements, demands on material technology are concomitantly rising. A growing trend towards molded in color solutions with low gloss aesthetics require TPE materials with ery low gloss, improved scratch resistance, and low temperature ductility. Innovations utilizing Teknor Apex's compounding technology have enabled the development of low gloss styrenic elastomers for airbag door applications that provide an optimized combination of low temperature performance, surface aesthetics (low gloss and improved scratch resistance), and ease of processing. This paper highlights the salient features of these new compounds and the effect of injection molding condition on the gloss at the surface of the cover.

  20. Considerations of metal joining processes for space fabrication, construction and repair

    Science.gov (United States)

    Russell, C.; Poorman, R.; Jones, C.; Nunes, A.; Hoffman, D.

    A comprehensive evaluation is conducted of candidate processes for metalworking in orbital (vacuum-microgravity) conditions. Attention is given to electron-beam welding, brazing, gas-tungsten arc welding, laser welding, plasma arc welding, and gas-metal arc welding. It is established that several of these processes will be required to cover all foreseeable requirements. Microgravity effects are considered minor, and efforts are being concentrated on problems associated with vacuum conditions and with process-operator safety.

  1. Joining the virtual teaching and learning (Moodle) space for students of anatomy.

    OpenAIRE

    Gazzotti, Andrea M.; Algieri, Ruben D.; Dogliotti, Claudia G.; Mazzoglio y Nabar, Martín J.; Rey, Lorena; Jiménez Villarruel, Humberto N.; Gómez, Ananquel; Pró, Eduardo A.

    2011-01-01

    Virtual teaching and learning spaces (VTLS) are a type of e-learning based on information and communication technology (ICT) with wide possibilities of application. The objective is to evaluate the degree of students’ adherence to the virtual space (Moodle) used as a complementary pedagogical tool in the teaching of Anatomy. The Moodle system was used from March to July 2010. A standardized and regulated survey was implemented for students attending courses in Anatomy (Medicine - UBA) during ...

  2. Carlsberg Circular Community: when a company and its suppliers join forces to implement eco-innovation

    DEFF Research Database (Denmark)

    Niero, Monia; Boas, S.H.; Olsen, Stig Irving

    2014-01-01

    are familiar with the Life Cycle Assessment (LCA) methodology and have successfully integrated it in product development and improvement. However, being inspired by the eco-efficiency principle, LCA aims to reduce the negative environmental footprint of human activities by optimizing product system...... and innovative solutions for beer packaging. However, from a value chain perspective C2C-inspired initiatives are potentially more beneficial. We will illustrate the challenges and opportunities emerging from the Carlsberg Circular Community experience in developing products that are optimized for re...

  3. Crash behavior of columns in relation to material properties and joining techniques

    NARCIS (Netherlands)

    Paas, M.H.J.W.; Bosma, F.; Nieboer, J.J.; Winter, L.C. de; Vreede, P.T.

    1998-01-01

    Ths strain rate behavior of mild-steel and high strength steel qualities has been investigated. The hardening as a function of the strain rate of a set of steel qualities was determined, and it was found that the gain in strength for high-strength steels is not in proportion to the static yield-stre

  4. Joined at the hip: linked characters and the problem of missing data in studies of disparity.

    Science.gov (United States)

    Smith, Andrew J; Rosario, Michael V; Eiting, Thomas P; Dumont, Elizabeth R

    2014-08-01

    Paleontological investigations into morphological diversity, or disparity, are often confronted with large amounts of missing data. We illustrate how missing discrete data affect disparity using a novel simulation for removing data based on parameters from published datasets that contain both extinct and extant taxa. We develop an algorithm that assesses the distribution of missing characters in extinct taxa, and simulates data loss by applying that distribution to extant taxa. We term this technique "linkage." We compare differences in disparity metrics and ordination spaces produced by linkage and random character removal. When we incorporated linkage among characters, disparity metrics declined and ordination spaces shrank at a slower rate with increasing missing data, indicating that correlations among characters govern the sensitivity of disparity analysis. We also present and test a new disparity method that uses the linkage algorithm to correct for the bias caused by missing data. We equalized proportions of missing data among time bins before calculating disparity, and found that estimates of disparity changed when missing data were taken into account. By removing the bias of missing data, we can gain new insights into the morphological evolution of organisms and highlight the detrimental effects of missing data on disparity analysis.

  5. The Taiwan Tobacco and Liquor Corporation: To 'join the ranks of global companies'.

    Science.gov (United States)

    Eckhardt, Jappe; Fang, Jennifer; Lee, Kelley

    2017-03-01

    Until the late 1990s, the Taiwan Tobacco and Liquor Corporation (TTL) focused almost exclusively on serving the domestic market as a highly protected monopoly. This paper describes how the company has adopted a more outward looking strategy since 2000, with ambitions to become a regional, and eventually global, business by 2021. Drawing on company documents and industry sources, the paper argues that this shift in strategy was a direct reaction to the decline in domestic market share following liberalisation of the Taiwanese tobacco market and adoption of tougher domestic tobacco control measures. Market opening occurred as a result of pressure from the U.S. Trade Representative in the 1980s, as well as World Trade Organization membership in 2002. It is argued that TTL's efforts to globalise operations have been limited by bureaucratic company management and structures, and ongoing political tension between Taiwan and China. However, the relative success of TTL's alcohol branch, and potential détente as the Taiwanese government reaches out to improve relations with China, may provide TTL with new opportunities to achieve its goal of becoming a regional player with global ambitions. This article is part of the special issue 'The Emergence of Asian Tobacco Companies: Implications for Global Health Governance.'

  6. Phase transformation and deformation behavior of NiTi-Nb eutectic joined NiTi wires.

    Science.gov (United States)

    Wang, Liqiang; Wang, Cong; Zhang, Lai-Chang; Chen, Liangyu; Lu, Weijie; Zhang, Di

    2016-04-06

    NiTi wires were brazed together via eutectic reaction between NiTi and Nb powder deposited at the wire contact region. Phase transformation and deformation behavior of the NiTi-Nb eutectic microstructure were investigated using transmission electron microscopy (TEM) and cyclic loading-unloading tests. Results show that R phase and B19' martensite transformation are induced by plastic deformation. R phase transformation, which significantly contributes to superelasticity, preferentially occurs at the interfaces between NiTi and eutectic region. Round-shaped Nb-rich phase with rod-like and lamellar-type eutectics are observed in eutectic regions. These phases appear to affect the deformation behavior of the brazed NiTi-Nb region via five distinct stages in stress-strain curves: (I) R phase reorientation, (II) R phase transformation from parent phase, (III) elastic deformation of reoriented martensite accompanied by the plastic deformation of Nb-rich phase and lamellar NiTi-Nb eutectic, (IV) B19' martensitic transformation, and (V) plastic deformation of the specimen.

  7. CONVERGENCE PROGRAM AND MACROECONOMIC POLICIES FOR ROMANIA JOINING THE EURO-ZONE

    Directory of Open Access Journals (Sweden)

    Magdalena R DULESCU

    2009-10-01

    Full Text Available Romania submitted a new update of its convergence program on 5 December 2007, covering the period 2007-2010. The budgetary strategy outlined in the program is not in line with the prudent fiscal policy necessary to contain the growing external deficit and inflationary pressures which put the convergence process at risk. In view of the Commission assessment and the need to ensure sustainable convergence, Romania is invited to: (i significantly strengthen the pace of adjustment towards the MTO by aiming for substantially more demanding budgetary targets in 2008 and subsequent years in order to contain the risk of an excessive deficit, foster macroeconomic stability and rein in widening external imbalances and address the risks to the long-term sustainability of public finances; (ii restrain the envisaged high increase in public spending, review its expenditure composition so as to enhance the economy’s growth potential and improve the planning and execution of expenditure within a binding medium-term framework; (iii adopt policies to contain inflationary pressures, complementing the recommended tighter fiscal stance, with appropriate public wage policy and further structural reforms.

  8. SOCIAL NETWORKING: REASONS TO JOIN AND THINGS DONE BY THE ROMANIAN CONSUMERS - AN EXPLORATORY ASSESSMENT

    Directory of Open Access Journals (Sweden)

    Pantea Carmen

    2009-05-01

    Full Text Available Initially developed in order to allow human interactions in the virtual environment as online communities of people having common concerns and willing to share and exchange ideas, today social networks represent one of the online marketing tools with the

  9. LHCb: Optimising query execution time in LHCb Bookkeeping System using partition pruning and partition wise joins

    CERN Multimedia

    Mathe, Z

    2013-01-01

    The LHCb experiment produces a huge amount of data which has associated metadata such as run number, data taking condition (detector status when the data was taken), simulation condition, etc. The data are stored in files, replicated on the Computing Grid around the world. The LHCb Bookkeeping System provides methods for retrieving datasets based on their metadata. The metadata is stored in a hybrid database model, which is a mixture of Relational and Hierarchical database models and is based on the Oracle Relational Database Management System (RDBMS). The database access has to be reliable and fast. In order to achieve a high timing performance, the tables are partitioned and the queries are executed in parallel. When we store large amounts of data the partition pruning is essential for database performance, because it reduces the amount of data retrieved from the disk and optimises the resource utilisation. This research presented here is focusing on the extended composite partitioning strategy such as rang...

  10. Holism and embodiment in nursing: using Goethean science to join 2 perspectives on patient care.

    Science.gov (United States)

    Mason, Deanna M

    2014-01-01

    Holism is a central concept in nursing theory, yet recently, embodiment has become prominent in the literature. Epistemological foundations from modern and contemporary philosophy are discussed and their relationship to nursing practice is explored to investigate the concepts of holism and embodiment. Nurses practice holistic care within the patient encounter while patients live an embodied experience. This creates inherent dissonance in the nurse-patient interaction. Goethean science is presented as a way to reconcile this discrepancy, to allow the nurse to better understand the patient's embodiment and, by default, his or her own embodiment. A new perspective of how nursing practice can use Goethean science and an embodied perspective are presented as a means to actualize Carper's fundamental pattern of knowing of personal knowledge within the nurse-patient interaction. With this approach, the nurse is able to examine the phenomenon of the patient with the patient to explore the essential nature that makes the patient who he or she is and what he or she is trying to become. During this exploration, the nurse uses the senses, language, and a critical mind to do what no machine or test could-to see the underlying meaningfulness and internal coherence of the patient. The intuitive revelation would expose nursing interventions simultaneously. Moving beyond the myopic perspective of how to keep "person" central to the nursing metaparadigm, nursing is beginning to see the embodiment of the patient as a means for understanding and providing care for patients. The challenge that remains is for nurses to see their own embodiment and reflect on if or how it is at odds with the necessity of providing holistic care to patients.

  11. Joining direct and indirect inverse calibration methods to characterize karst, coastal aquifers

    Science.gov (United States)

    De Filippis, Giovanna; Foglia, Laura; Giudici, Mauro; Mehl, Steffen; Margiotta, Stefano; Negri, Sergio

    2016-04-01

    Parameter estimation is extremely relevant for accurate simulation of groundwater flow. Parameter values for models of large-scale catchments are usually derived from a limited set of field observations, which can rarely be obtained in a straightforward way from field tests or laboratory measurements on samples, due to a number of factors, including measurement errors and inadequate sampling density. Indeed, a wide gap exists between the local scale, at which most of the observations are taken, and the regional or basin scale, at which the planning and management decisions are usually made. For this reason, the use of geologic information and field data is generally made by zoning the parameter fields. However, pure zoning does not perform well in the case of fairly complex aquifers and this is particularly true for karst aquifers. In fact, the support of the hydraulic conductivity measured in the field is normally much smaller than the cell size of the numerical model, so it should be upscaled to a scale consistent with that of the numerical model discretization. Automatic inverse calibration is a valuable procedure to identify model parameter values by conditioning on observed, available data, limiting the subjective evaluations introduced with the trial-and-error technique. Many approaches have been proposed to solve the inverse problem. Generally speaking, inverse methods fall into two groups: direct and indirect methods. Direct methods allow determination of hydraulic conductivities from the groundwater flow equations which relate the conductivity and head fields. Indirect methods, instead, can handle any type of parameters, independently from the mathematical equations that govern the process, and condition parameter values and model construction on measurements of model output quantities, compared with the available observation data, through the minimization of an objective function. Both approaches have pros and cons, depending also on model complexity. For

  12. Failure of dissimilar material bonded joints

    Science.gov (United States)

    Konstantakopoulou, M.; Deligianni, A.; Kotsikos, G.

    2016-03-01

    Joining of materials in structural design has always been a challenge for engineers. Bolting and riveting has been used for many years, until the emergence of fusion welding which revolutionised construction in areas such as shipbuilding, automotive, infrastructure and consumer goods. Extensive research in the past 50 years has resulted in better understanding of the process and minimised the occurrence of failures associated with fusion welding such as, residual stress cracking, stress corrosion and corrosion fatigue cracking, localised reduction in mechanical properties due to microstructural changes (heat affected zone) etc. Bonding has been a technique that has been proposed as an alternative because it eliminates several of the problems associated with fusion welding. But, despite some applications it has not seen wide use. There is however a renewed interest in adhesively bonded joints, as designers look for ever more efficient structures which inevitably leads to the use and consequently joining of combinations of lightweight materials, often with fundamentally different mechanical and physical properties. This chapter provides a review of adhesively bonded joints and reports on improvements to bonded joint strength through the introduction of carbon nanotubes at the bond interface. Results from various workers in the field are reported as well as the findings of the authors in this area of research. It is obvious that there are several challenges that need to be addressed to further enhance the strength of bonded joints and worldwide research is currently underway to address those shortcomings and build confidence in the implementation of these new techniques.

  13. Pseudomyrmex ants and Acacia host plants join efforts to protect their mutualism from microbial threats.

    Science.gov (United States)

    González-Teuber, Marcia; Heil, Martin

    2010-07-01

    Plants express numerous 'pathogenesis-related' (PR) proteins to defend themselves against pathogen infection. We recently discovered that PR-proteins such as chitinases, glucanases, peroxidases and thaumatin-like proteins are also functioning in the protection of extrafloral nectar (EFN) of Mexican Acacia myrmecophytes. These plants produce EFN, cellular food bodies and nesting space to house defending ant species of the genus Pseudomyrmex. More than 50 PR-proteins were discovered in this EFN and bioassays demonstrated that they actively can inhibit the growth of fungi and other phytopathogens. Although the plants can, thus, express PR-proteins and secrete them into the nectar, the leaves of these plants exhibit reduced activities of chitinases as compared to non-myrmecophytic plants and their antimicrobial protection depends on the mutualistic ants. When we deprived plants of their resident ants we observed higher microbial loads in the leaves and even in the tissue of the nectaries, as compared to plants that were inhabited by ants. The indirect defence that is achieved through an ant-plant mutualism can protect plants also from infections. Future studies will have to investigate the chemical nature of this mechanism in order to understand why plants depend on ants for their antimicrobial defence.

  14. Joined at the hip: kinetochores, microtubules, and spindle assembly checkpoint signaling.

    Science.gov (United States)

    Sacristan, Carlos; Kops, Geert J P L

    2015-01-01

    Error-free chromosome segregation relies on stable connections between kinetochores and spindle microtubules. The spindle assembly checkpoint (SAC) monitors such connections and relays their absence to the cell cycle machinery to delay cell division. The molecular network at kinetochores that is responsible for microtubule binding is integrated with the core components of the SAC signaling system. Molecular-mechanistic understanding of how the SAC is coupled to the kinetochore-microtubule interface has advanced significantly in recent years. The latest insights not only provide a striking view of the dynamics and regulation of SAC signaling events at the outer kinetochore but also create a framework for understanding how that signaling may be terminated when kinetochores and microtubules connect.

  15. Fatigue Behaviors of Self-Piercing Rivets Joining Similar and Dissimilar Sheet Metals

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2007-01-01

    This paper summarizes the fatigue test results of self-piercing rivet (SPR) joints between similar and dissimilar sheet metals. The influences of material grades, material thickness, piercing direction and the use of structural adhesive on the rivet samples’ fatigue behaviors were investigated. Fatigue test results indicate that SPR joints have superior fatigue strength than resistance spot weld (RSW) joints for the same material combinations. The application of structure adhesive also significantly enhances the fatigue strength of the joint samples; this is particularly true for the lap shear loading configuration. In addition, different piercing directions for SPR joints have a noticeable effect on the static and fatigue strength of the joints. The joint fatigue results presented in this paper can offer design engineers with the durability data for SPR joints with these material combinations. Moreover, it will provide manufacturing engineers with some insights on the effects of different manufacturing parameters on the strength and durability of these joints.

  16. In Vivo Analysis of Cajal Body Movement, Separation, and Joining in Live Human Cells

    OpenAIRE

    Platani, Melpomeni; Goldberg, Ilya; Swedlow, Jason R.; Lamond, Angus I.

    2000-01-01

    Cajal bodies (also known as coiled bodies) are subnuclear organelles that contain specific nuclear antigens, including splicing small nuclear ribonucleoproteins (snRNPs) and a subset of nucleolar proteins. Cajal bodies are localized in the nucleoplasm and are often found at the nucleolar periphery. We have constructed a stable HeLa cell line, HeLaGFP-coilin, that expresses the Cajal body marker protein, p80 coilin, fused to the green fluorescent protein (GFP-coilin). The localization pattern ...

  17. Malaria parasites utilize both homologous recombination and alternative end joining pathways to maintain genome integrity

    OpenAIRE

    2013-01-01

    Malaria parasites replicate asexually within their mammalian hosts as haploid cells and are subject to DNA damage from the immune response and chemotherapeutic agents that can significantly disrupt genomic integrity. Examination of the annotated genome of the parasite Plasmodium falciparum identified genes encoding core proteins required for the homologous recombination (HR) pathway for repairing DNA double-strand breaks (DSBs), but surprisingly none of the components of the canonical non-hom...

  18. Pseudomyrmex ants and Acacia host plants join efforts to protect their mutualism from microbial threats

    OpenAIRE

    González-Teuber, Marcia; Heil, Martin

    2010-01-01

    Plants express numerous ‘pathogenesis-related’ (PR) proteins to defend themselves against pathogen infection. We recently discovered that PR-proteins such as chitinases, glucanases, peroxidases and thaumatin-like proteins are also functioning in the protection of extra-floral nectar (EFN) of Mexican Acacia myrmecophytes. These plants produce EFN, cellular food bodies and nesting space to house defending ant species of the genus Pseudomyrmex. More than 50 PR-proteins were discovered in this EF...

  19. Prediction of allosteric sites and mediating interactions through bond-to-bond propensities

    Science.gov (United States)

    Amor, B. R. C.; Schaub, M. T.; Yaliraki, S. N.; Barahona, M.

    2016-08-01

    Allostery is a fundamental mechanism of biological regulation, in which binding of a molecule at a distant location affects the active site of a protein. Allosteric sites provide targets to fine-tune protein activity, yet we lack computational methodologies to predict them. Here we present an efficient graph-theoretical framework to reveal allosteric interactions (atoms and communication pathways strongly coupled to the active site) without a priori information of their location. Using an atomistic graph with energy-weighted covalent and weak bonds, we define a bond-to-bond propensity quantifying the non-local effect of instantaneous bond fluctuations propagating through the protein. Significant interactions are then identified using quantile regression. We exemplify our method with three biologically important proteins: caspase-1, CheY, and h-Ras, correctly predicting key allosteric interactions, whose significance is additionally confirmed against a reference set of 100 proteins. The almost-linear scaling of our method renders it suitable for high-throughput searches for candidate allosteric sites.

  20. High-Cost Patients Had Substantial Rates Of Leaving Medicare Advantage And Joining Traditional Medicare.

    Science.gov (United States)

    Rahman, Momotazur; Keohane, Laura; Trivedi, Amal N; Mor, Vincent

    2015-10-01

    Medicare Advantage payment regulations include risk-adjusted capitated reimbursement, which was implemented to discourage favorable risk selection and encourage the retention of members who incur high costs. However, the extent to which risk-adjusted capitation has succeeded is not clear, especially for members using high-cost services not previously considered in assessments of risk selection. We examined the rates at which participants who used three high-cost services switched between Medicare Advantage and traditional Medicare. We found that the switching rate from 2010 to 2011 away from Medicare Advantage and to traditional Medicare exceeded the switching rate in the opposite direction for participants who used long-term nursing home care (17 percent versus 3 percent), short-term nursing home care (9 percent versus 4 percent), and home health care (8 percent versus 3 percent). These results were magnified among people who were enrolled in both Medicare and Medicaid. Our findings raise questions about the role of Medicare Advantage plans in serving high-cost patients with complex care needs, who account for a disproportionately high amount of total health care spending.

  1. Synthesis and Pharmacological Evaluation of Modified Adenosines Joined to Mono-Functional Platinum Moieties

    Directory of Open Access Journals (Sweden)

    Stefano D'Errico

    2014-07-01

    Full Text Available The synthesis of four novel platinum complexes, bearing N6-(6-amino-hexyladenosine or a 1,6-di(adenosin-N6-yl-hexane respectively, as ligands of mono-functional cisplatin or monochloro(ethylendiamineplatinum(II, is reported. The chemistry exploits the high affinity of the charged platinum centres towards the N7 position of the adenosine base system and a primary amine of an alkyl chain installed on the C6 position of the purine. The cytotoxic behaviour of the synthesized complexes has been studied in A549 adenocarcinomic human alveolar basal epithelial and MCF7 human breast adenocarcinomic cancer cell lines, in order to investigate their effects on cell viability and proliferation.

  2. Terahertz wave behaviours in ceramic and metal structures fabricated by spatial joining of micro-stereolithography

    Energy Technology Data Exchange (ETDEWEB)

    Kirihara, S; Niki, T; Kaneko, M [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka Ibaraki, 567-0047 Osaka (Japan)], E-mail: kirihara@jwri.osaka-u.ac.jp

    2009-05-01

    We have newly developed micro-stereolithography system to realize freeform fabrication of micrometer order 3D metal structures. In this process, the photo-sensitive resin paste mixed with nanometer sized ceramic and metal particles was spread on a glass substrate with 10 {mu}m in layer thickness by using a mechanical knife edge, and two-dimensional images of UV ray were exposed using DMD (Digital Micro-mirror Device) with 2 {mu}m in part accuracy. Through the layer by layer stacking process, micrometer order three-dimensional objects were formed. Dense metal structures could be obtained by dewaxing and successive sintering of the formed objects. In our recent investigation, micro photonic crystals with lattice structures of alumina or pure copper were fabricated in order to control electromagnetic wave propagation in a terahertz (THz) frequency range. The micro photonic crystals with a diamond structure perfectly reflected the THz wave by Bragg diffraction.

  3. Algerian Economy and Multilateral Trading System: Why Is It So Hard to Join the WTO

    Directory of Open Access Journals (Sweden)

    Khayreddine Belaaze

    2014-08-01

    Full Text Available The main purpose of this paper is to provide a overview on different stages of the negotiations with World Trade Organization, since 1987 date of submission the application for accession, Algeria still trying to snatch accession card with minimum cost, where it tries to provide small guarantees, but some WTO members raises reservations over some issues like aspects related to investment, for example: the Rule of 49/51, and domestic component, prevention of exporting, besides the agricultural issue which takes advantage of domestic subsidies and exporting subsides, also services industry knows low degree of openness, especially In some sensitive areas such as financial services, telecommunications.

  4. Rethinking Education: When surgeons and engineering students join forces to solve real problems, success follows.

    Science.gov (United States)

    Allan, Gregory

    2015-01-01

    The Engineers in Scrubs (EiS) training program at the University of British Columbia, affiliated with the Faculty of Applied Science?s Biomedical Engineering Graduate (BMEG) Program, is not a typical graduate school course. Nor does it follow a traditional master?s course rubric that culminates with a tidy end-of-year project. Rather, the course is designed to push students to prototype innovative medical devices, encourage health care collaborations, and create an unprecedented interface between technology and health care to further medicine.

  5. Joined against Pain and Gathered in Hope: The Role of Hokies United

    Science.gov (United States)

    Schneiter, Steven R.; MacEachran, Brianne

    2008-01-01

    After April 16, 2007, Hokies United needed to heal itself and the Virginia Tech community. "About Campus" editorial assistant Brianne MacEachran interviewed Steve Schneiter, a faculty co-creator of the campus group that has organized responses to tragedies since the events of September 11, 2001, about managing suffering, this time their own.…

  6. Large Deviations Methods and the Join-the-Shortest-Queue Model

    NARCIS (Netherlands)

    Ridder, Ad; Shwartz, Adam

    2005-01-01

    We develop a methodology for studying ''large deviations type'' questions. Our approach does not require that the large deviations principle holds, and is thus applicable to a larg class of systems. We study a system of queues with exponential servers, which share an arrival stream. Arrivals are rou

  7. Joined-up Working: Improving Young People's Sexual Health and Enhancing Social Inclusion?

    Science.gov (United States)

    Philip, Kate; Shucksmith, Janet; Tucker, Janet; van Teijlingen, Edwin; Immamura, Mari; Penfold, Suzanne

    2006-01-01

    This paper builds on debates about the meaning and definition of social exclusion through an empirical analysis undertaken as part of a four-year evaluation study of a Scottish demonstration project on young peoples' sexual health. It examines how interventions to improve sexual well-being might be construed as a way of promoting social inclusion,…

  8. Joining and leaving sex work: experiences of women in Kigali, Rwanda

    NARCIS (Netherlands)

    Ingabire, M.C.; Mitchell, K.; Veldhuijzen, N.; Umulisa, M.M.; Nyinawabega, J.; Kesteleyn, E.; van Steijn, M.; van de Wijgert, J.; Pool, R.

    2012-01-01

    Although sex work can bring significant economic benefit there are serious downsides, not least vulnerability to adverse sexual health outcomes. Focus-groups discussions and in-depth interviews were conducted with 70 female sex workers to explore the context in which they started sex work, their mot

  9. Molecular dynamics simulations of the hydration of poly(vinyl methyl ether): Hydrogen bonds and quasi-hydrogen bonds

    Institute of Scientific and Technical Information of China (English)

    WU RongLiang; JI Qing; KONG Bin; YANG XiaoZhen

    2008-01-01

    Atomistic detailed hydration structures of poly(vinyl methyl ether) (PVME) have been investigated by molecular dynamics simulations under 300 K at various concentrations. Both radial distribution func-tions and the distance distributions between donors and acceptors in hydrogen bonds show that the hydrogen bonds between the polymer and water are shorter by 0.005 nm than those between water molecules. The Quasi-hydrogen bonds take only 7.2% of the van der Waals interaction pairs. It was found the hydrogen bonds are not evenly distributed along the polymer chain, and there still exists a significant amount (10%) of ether oxygen atoms that are not hydrogen bonded to water at a concentra-tion as low as 3.3%. This shows that in polymer solutions close contacts occur not only between polymer chains but also between chain segments within the polymer, which leads to inefficient con-tacts between ether oxygen atoms and water molecules. Variation of the quasi-hydrogen bonds with the concentration is similar to that of hydrogen bonds, but the ratio of the repeat units forming quasi-hydrogen bonds to those forming hydrogen bonds approaches 0.2. A transition was found in the demixing enthalpy at around 30% measured by dynamic testing differential scanning calorimetry (DTDSC) for aqueous solutions of a mono-dispersed low molecular weight PVME, which can be related to the transition of the fractions of hydrogen bonds and quasi-hydrogen bonds at ~27%. The transition of the fractions of hydrogen bonds and quasi-hydrogen bonds at ~27% can be used to explain the demixing enthalpy transition at 30% at a molecular scale. In addition, at the concentration of 86%, each ether oxygen atom bonded with water is assigned 1.56 water molecules on average, and 'free' water molecules emerge at the concentration of around 54%.

  10. Molecular dynamics simulations of the hydration of poly(vinyl methyl ether):Hydrogen bonds and quasi-hydrogen bonds

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Atomistic detailed hydration structures of poly(vinyl methyl ether)(PVME) have been investigated by molecular dynamics simulations under 300 K at various concentrations. Both radial distribution functions and the distance distributions between donors and acceptors in hydrogen bonds show that the hydrogen bonds between the polymer and water are shorter by 0.005 nm than those between water molecules. The Quasi-hydrogen bonds take only 7.2% of the van der Waals interaction pairs. It was found the hydrogen bonds are not evenly distributed along the polymer chain,and there still exists a significant amount(10%) of ether oxygen atoms that are not hydrogen bonded to water at a concentration as low as 3.3%. This shows that in polymer solutions close contacts occur not only between polymer chains but also between chain segments within the polymer,which leads to inefficient contacts between ether oxygen atoms and water molecules. Variation of the quasi-hydrogen bonds with the concentration is similar to that of hydrogen bonds,but the ratio of the repeat units forming quasi-hydrogen bonds to those forming hydrogen bonds approaches 0.2. A transition was found in the demixing enthalpy at around 30% measured by dynamic testing differential scanning calorimetry(DTDSC) for aqueous solutions of a mono-dispersed low molecular weight PVME,which can be related to the transition of the fractions of hydrogen bonds and quasi-hydrogen bonds at ~27%. The transition of the fractions of hydrogen bonds and quasi-hydrogen bonds at ~27% can be used to explain the demixing enthalpy transition at 30% at a molecular scale. In addition,at the concentration of 86%,each ether oxygen atom bonded with water is assigned 1.56 water molecules on average,and ’free’ water molecules emerge at the concentration of around 54%.

  11. Scaling of Fiber Laser Systems Based on Novel Components and High Power Capable Packaging and Joining Technologies

    Science.gov (United States)

    2010-09-01

    2800 λ [nm] Yb3+ rare-earth doped fibers, kW average power levels available long wavelength by heavy metal cation fibers (e.g zirconium, ZBLAN ...l ri Laser Splicing/ Welding r li i / l i Contact Bonding t t i Wafer Level Bonding Mineralic, Fusion. Anodic, Eutectic, Glass -frit, liquid

  12. Jiangxi Copper and Yates Joined Hands in High-Grade Copper Foil Project Construction

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正> The construction of a large-scale copper foilproject recently started in the High-Tech De-velopment Zone of Nanchang,the capital ofJiangxi Province.This new copper foil factory,with a designed annual production capacity of6,000 tons of high-grade copper foil,is a jointventure project between Jiangxi Copper Group,the No.1 copper producer in China,and YatesInc.,a leading US copper product company andthe world’s first electrical circuit board maker.

  13. Bond breaking in a Morse chain under tension: Fragmentation patterns, higher index saddles, and bond healing

    Science.gov (United States)

    Mauguière, F. A. L.; Collins, P.; Ezra, G. S.; Wiggins, S.

    2013-04-01

    We investigate the fragmentation dynamics of an atomic chain under tensile stress. We have classified the location, stability type (indices), and energy of all equilibria for the general n-particle chain, and have highlighted the importance of saddle points with index >1. We show that for an n = 2-particle chain under tensile stress the index 2 saddle plays a central role in organizing the dynamics. We apply normal form theory to analyze phase space structure and dynamics in a neighborhood of the index 2 saddle. We define a phase dividing surface (DS) that enables us to classify trajectories passing through a neighborhood of the saddle point using the values of the integrals associated with the normal form. We also generalize our definition of the dividing surface and define an extended dividing surface (EDS), which is used to sample and classify all trajectories that pass through a phase space neighborhood of the index 2 saddle at total energies less than that of the saddle. Classical trajectory simulations are used to study fragmentation patterns for the n = 2 chain under tension. That is, we investigate the relative probability for breaking one bond versus concerted fission of several (two, in this case) bonds. Initial conditions for trajectories are obtained by sampling the EDS at constant energy. We sample trajectories at fixed energies both above and below the energy of the saddle. The fate of trajectories (single versus multiple bond breakage) is explored as a function of the location of the initial condition on the EDS, and a connection made to the work of Chesnavich on collision-induced dissociation. A significant finding is that we can readily identify trajectories that exhibit bond healing. Such trajectories pass outside the nominal (index 1) transition state for single bond dissociation, but return to the potential well region, possibly several times, before ultimately dissociating.

  14. GRB 991216 Joins the Jet Set Discovery and Monitoring of its Optical Afterglow

    CERN Document Server

    Halpern, J P; Mirabal, N; Kassin, S; Thorstensen, J R; Keel, W C; Diercks, A H; Bloom, J S; Harrison, F; Mattox, J R; Eracleous, M

    2000-01-01

    The optical light curve of the energetic gamma-ray burst GRB 991216 is consistent with jet-like behavior in which a power-law decay steepens from t**(-1.22 +/- 0.04) at early times to t**(-1.53 +/- 0.05) in a gradual transition at around 2 d. The derivation of the late-time decay slope takes into account the constant contribution of a host or intervening galaxy which was measured 110 d after the event at R = 24.56 +/- 0.14, although the light curve deviates from a single power law whether or not a constant term is included. The early-time spectral energy distribution of the afterglow can be described as F_nu ~ nu**(-0.74 +/- 0.05) or flatter between optical and X-ray, which, together with the slow initial decay, is characteristic of standard adiabatic evolution in a uniformly dense medium. Assuming that a reported absorption-line redshift of 1.02 is correct, the apparent isotropic energy of 6.7 x 10**53 erg is reduced by a factor of ~ 200 in the jet model, and the initial half-opening angle is ~ 6 deg. GRB 99...

  15. Teach First Norway - who joins and what are their initial motivations for teaching?

    Directory of Open Access Journals (Sweden)

    Katrine Nesje

    2016-04-01

    Full Text Available Motivasjon for å undervise er et tema som er mye diskutert i offentlige debatter og i forskningslitteraturen. Grunnen til dette er at læreres profesjonelle motivasjon har vist seg å påvirke elevenes motivasjon, læreres tilfredshet i jobben, fravær og turnover i læreryrket, samt rekruttering av nye lærere. Alternative lærerutdanninger som tilbyr en raskere vei inn i læreryrket har i de senere årene blitt etablert, både i Norge og internasjonalt. Denne studien undersøker om den profesjonelle motivasjonen til kandidater som rekrutteres til disse programmene har spesielle kjennetegn. Artikkelen undersøker både motivasjon for undervisning og motivasjon for å delta i det alternative lederopplærings- og lærerutdanningsprogrammet Teach First Norway. Datamaterialet består av spørreskjemadata og intervjudata fra ett kull (N=13 Teach First Norway-kandidater. Basert på spørreskjemadata ble det utført en klyngeanalyse som fant tre motivasjonsprofiler: “Lav altruistisk motivasjon”, “Interesse for undervisning” og “Høy altruistisk motivasjon”. Ved hjelp av kvalitative intervjuer ble motivasjonsprofilene utdypet. Resultatene viser at samspillet mellom deltakernes ulike motivasjonsfaktorer er kompleks og unik. Det stereotype bildet av en Teach First Norway-kandidat som bruker programmet som et springbrett inn i lederstillinger i næringslivet nyanseres som følge av funnene.Nøkkelord: alternativ lærerutdanning, motivasjon for å undervise, karriere, Teach First NorwayAbstractTeacher motivation is a widely discussed topic in public debates and educational research literature. Prior research has found that teachers’ professional motivation impacts students’ motivation, teachers’ professional satisfaction, teacher absenteeism and turnover, as well as the recruitment of new teachers. Recently, the introduction of alternative teacher education programmes has provided a faster way into the teaching profession. This study

  16. Effect of thione primers on adhesive bonding between an indirect composite material and Ag-Pd-Cu-Au alloy.

    Science.gov (United States)

    Imai, Hideyuki; Koizumi, Hiroyasu; Shimoe, Saiji; Hirata, Isao; Matsumura, Hideo; Nikawa, Hiroki

    2014-01-01

    The current study evaluated the effect of primers on the shear bond strength of an indirect composite material joined to a silverpalladium-copper-gold (Ag-Pd-Cu-Au) alloy (Castwell). Disk specimens were cast from the alloy and were air-abraded with alumina. Eight metal primers were applied to the alloy surface. A light-polymerized indirect composite material (Solidex) was bonded to the alloy. Shear bond strength was determined both before and after the application of thermocycling. Two groups primed with Metaltite (thione) and M. L. Primer (sulfide) showed the greatest post-thermocycling bond strength (8.8 and 6.5 MPa). The results of the X-ray photoelectron spectroscopic (XPS) analysis suggested that the thione monomer (MTU-6) in the Metaltite primer was strongly adsorbed onto the Ag-Pd-Cu-Au alloy surface even after repeated cleaning with acetone. The application of either the thione (MTU-6) or sulfide primer is effective for enhancing the bonding between a composite material and Ag-Pd-Cu-Au alloy.

  17. On the strong metric dimension of corona product graphs and join graphs

    CERN Document Server

    Kuziak, Dorota; Rodriguez-Velazquez, Juan A

    2012-01-01

    Let $G$ be a connected graph. A vertex $w$ strongly resolves a pair $u$, $v$ of vertices of $G$ if there exists some shortest $u-w$ path containing $v$ or some shortest $v-w$ path containing $u$. A set $W$ of vertices is a strong resolving set for $G$ if every pair of vertices of $G$ is strongly resolved by some vertex of $W$. The smallest cardinality of a strong resolving set for $G$ is called the strong metric dimension of $G$. It is known that the problem of computing this invariant is NP-hard. It is therefore desirable to reduce the problem of computing the strong metric dimension of product graphs, to the problem of computing some parameter of the factor graphs. We show that the problem of finding the strong metric dimension of the corona product $G\\odot H$, of two graphs $G$ and $H$, can be transformed to the problem of finding certain clique number of $H$. As a consequence of the study we show that if $H$ has diameter two, then the strong metric dimension of $G\\odot H$ is obtained from the strong metri...

  18. [Corrosion resistance and bond strength of dental alloys].

    Science.gov (United States)

    Schwickerath, H

    1990-07-01

    Investigated Ni-alloys, which showed extensive solubility of Ni particles in corrosion bathes due to DIN 13927, also revealed pronounced lost of bond strength to ceramic veneers when immersed into corrosion bathes of equal constitution. Noble metal alloys with a gold concentration more than 50 percent, however, showed no such large lost of bond strength. Pd alloys showed a lost of bond strength which increased with their Ga concentration. Co alloys revealed a behavior similar to the Ni alloys but with no obvious correlation between solubility and lost of bond strength.

  19. A simple surface treatment and characterization of AA 6061 aluminum alloy surface for adhesive bonding applications

    Energy Technology Data Exchange (ETDEWEB)

    Saleema, N., E-mail: saleema.noormohammed@imi.cnrc-nrc.gc.ca [National Research Council of Canada (ATC-NRC), 501 Boulevard University East, Saguenay, Quebec G7H 8C3 (Canada); Sarkar, D.K. [Centre Universitaire de Recherche sur l' Aluminium (CURAL), University of Quebec at Chicoutimi (UQAC), 555 Boulevard University East, Saguenay, Quebec G7H 2B1 (Canada); Paynter, R.W. [Institut National de la Recherche Scientifique Energie Materiaux Telecommunications (INRS-EMT), 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Gallant, D.; Eskandarian, M. [National Research Council of Canada (ATC-NRC), 501 Boulevard University East, Saguenay, Quebec G7H 8C3 (Canada)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer A very simple surface treatment method to achieve excellent and durable aluminum adhesive bonding. Black-Right-Pointing-Pointer Our method involves simple immersion of aluminum in very dilute NaOH solution at room temperature with no involvement of strong acids or multiple procedures. Black-Right-Pointing-Pointer Surface analysis via various surface characterization techniques showed morphological and chemical modifications favorable for obtaining highly durable bond strengths on the treated surface. Black-Right-Pointing-Pointer Safe, economical, reproducible and simple method, easily applicable in industries. - Abstract: Structural adhesive bonding of aluminum is widely used in aircraft and automotive industries. It has been widely noted that surface preparation of aluminum surfaces prior to adhesive bonding plays a significant role in improving the strength of the adhesive bond. Surface cleanliness, surface roughness, surface wettability and surface chemistry are controlled primarily by proper surface treatment methods. In this study, we have employed a very simple technique influencing all these criteria by simply immersing aluminum substrates in a very dilute solution of sodium hydroxide (NaOH) and we have studied the effect of varying the treatment period on the adhesive bonding characteristics. A bi-component epoxy adhesive was used to join the treated surfaces and the bond strengths were evaluated via single lap shear (SLS) tests in pristine as well as degraded conditions. Surface morphology, chemistry, crystalline nature and wettability of the NaOH treated surfaces were characterized using various surface analytical tools such as scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDX), optical profilometry, infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and contact angle goniometry. Excellent adhesion characteristics with complete cohesive failure

  20. Joining Technology of Dissimilar Materials for Automotive Components(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    Meung Ho Rhee; Jong Ho Song; Woo Young Chung; Young Myoung Kim

    2004-01-01

    Joining techniques of dissimilar materials for lightweight multi-material automotive body structure were discussed. The joining of 1 .4 mm thickness steel and 2 mm thickness of Al were performed by the new method that is hybrid laser welding system. After aluminum and steel were welded by laser hybrid welding process, the micro-structure investment and the micro-hardness test were carried out. Hybrid laser welding promises a bright future in joining technology of dissimilar materials for automotive components.

  1. Oxidative damage of workers in secondary metal recovery plants affected by smoking status and joining the smelting work.

    Science.gov (United States)

    Chia, Taipau; Hsu, Ching Yi; Chen, Hsiu Ling

    2008-04-01

    In Taiwan, secondary copper smelters and zinc recovery plants primarily utilize recovering metal from scrap and dross, and handles mostly fly ash and slag with high temperature to produce ZnO from the iron and steel industry. The materials may contain organic impurities, such as plastic and organic chloride chemicals, and amounts of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are produced during the smelting process. Therefore, secondary metal recovery industries are major emission sources of PCDD/Fs, which may have been demonstrated to elicit oxidative stress and to involve the production of plasma malondialdehyde (MDA). Many studies have also indicated that the intake of antioxidants, smoking, age and exposure to environmental pollutants may be implicated to DNA damage or lipid peroxidation. This study therefore aims to elucidate the roles of occupational exposure like joining the smelting work, age, smoking and alcohol status, and antioxidant intake on oxidative damage in secondary metal recovery workers in Taiwan. 73 workers were recruited from 2 secondary metal recovery plants. The analysis of 8-hydroxydeoxyguanosine (8-OH-dG) in urine, DNA strand breakage (comet assay) and lipid peroxidation (MDA) in blood samples were completed for all of the workers. The results showed that the older subjects exhibited significantly lower levels of 8-OH-dG and MDA than younger subjects. Our investigation also showed that working departments were in related to plasma MDA and DNA strand breakage levels of nonsmokers, however, the observation become negligible in smokers. And it is implicated that cigarette type might affect 8-OH-dG levels in secondary metal recovery workers. Since, adding to results above, the MDA level in production workers was significantly higher than those in managerial departments, it is important for the employers to make efforts on improving occupational environments or serving protective equipments to protect workers

  2. Friction riveting. Development and analysis of a new joining technique for polymer-metal multi-materials structures

    Energy Technology Data Exchange (ETDEWEB)

    Amancio, S.

    2007-07-01

    A new Friction Riveting technique for polymeric-metallic joints was developed, demonstrated and characterized in this work, as an alternative, reliable, environmental compatible and economically viable spot joining process. In the simplest process variant a rotating cylindrical metallic rivet is inserted in a thermoplastic base plate. The high rotation speed and pressure increase friction and heat is generated. The local increase in temperature induces the formation of a softened/molten polymer layer around the tip of the rotating rivet. When a certain penetration depth is achieved the heat input rate becomes higher than heat outflow (owing to the low polymer thermal conductivity), temperature highly increases and the rivet tip plasticizes. At this point rotation is stopped and the forging pressure applied, so the plasticized rivet tip is deformed by the opposite reactive forces of colder polymeric volumes, assuming a paraboloidal pattern; after cooling it becomes anchored in the polymeric base plate. In this work case-study joints on commercially available polyetherimide (PEI) and aluminium 2024- T351(Al-Cu-Mg alloy) were chosen for demonstrating proposed theories, models and mechanisms, as well as an analytical heat input model. Sound friction riveted point-on-plate and single-rivet overlap joints with elevated joint efficiencies in terms of base materials strength were obtained (joint efficiencies for point-on-plate joints: 60 %.93 %; for overlaps: 70 %) through tensile and lap shear testing at room temperature. The influence of process parameters (rotational speed, total time and total pressure) on process variables and joint properties were evaluated by thermometry, infrared thermography, microscopy, Vickers microhardness, X-ray microtomography and by gel permeation chromatography. Temperature (average maximal temperatures 500 deg C) was directly proportional to rotation speed, total time and total pressure. Volumetric flaw formation was directly proportional

  3. Disulfide bonds and glycosylation in fungal peroxidases.

    Science.gov (United States)

    Limongi, P; Kjalke, M; Vind, J; Tams, J W; Johansson, T; Welinder, K G

    1995-01-15

    Four conserved disulfide bonds and N-linked and O-linked glycans of extracellular fungal peroxidases have been identified from studies of a lignin and a manganese peroxidase from Trametes versicolor, and from Coprinus cinereus peroxidase (CIP) and recombinant C. cinereus peroxidase (rCIP) expressed in Aspergillus oryzae. The eight cysteine residues are linked 1-3, 2-7, 4-5 and 6-8, and are located differently from the four conserved disulfide bridges present in the homologous plant peroxidases. CIP and rCIP were identical in their glycosylation pattern, although the extent of glycan chain heterogeneity depended on the fermentation batch. CIP and rCIP have one N-linked glycan composed only of GlcNAc and Man at residue Asn142, and two O-linked glycans near the C-terminus. The major glycoform consists of single Man residues at Thr331 and at Ser338. T. versicolor lignin isoperoxidase TvLP10 contains a single N-linked glycan composed of (GlcNAc)2Man5 bound to Asn103, whereas (GlcNAc)2Man3 was found in T. versicolor manganese isoperoxidase TvMP2 at the same position. In addition, mass spectrometry of the C-terminal peptide of TvMP2 indicated the presence of five Man residues in O-linked glycans. No phosphate was found in these fungal peroxidases.

  4. Disulphide bond formation in food protein aggregation and gelation

    NARCIS (Netherlands)

    Visschers, R.W.; Jongh, de H.H.J.

    2005-01-01

    In this short review we discuss the role of cysteine residues and cystine bridges for the functional aggregation of food proteins. We evaluate how formation and cleavage of disulphide bonds proceeds at a molecular level, and how inter- and intramolecular disulfide bonds can be detected and modified.

  5. Genetic probing of homologous recombination and non-homologous end joining during meiotic prophase in irradiated mouse spermatocytes

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Emad A. [Department of Endocrinology and Metabolism, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Department of Zoology, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Philippens, Marielle E.P.; Kal, Henk B. [Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Rooij, Dirk G. de, E-mail: d.g.derooij@uu.nl [Department of Endocrinology and Metabolism, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Center for Reproductive Medicine, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam (Netherlands); Boer, Peter de [Department of Obstetrics and Gynaecology, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen (Netherlands)

    2010-06-01

    This study was designed to obtain a better insight into the relative contribution of homologous recombination (HR) and non-homologous end joining (NHEJ) to the repair of radiation-induced DNA double-strand breaks (DSBs) at first meiotic prophase. Early and late pachytene and early diplotene spermatocytes that had completed crossing over were sampled. We studied the kinetics of {gamma}-H2AX chromatin foci removal after irradiation of mice deficient for HR and mice deficient for NHEJ. Analyzing {gamma}-H2AX signals in unirradiated RAD54/RAD54B deficient spermatocytes indicated incomplete meiotic recombination repair due to the pronounced increase of {gamma}-H2AX foci in late prophase primary spermatocytes. In these mice, 8 h after irradiation, early pachytene spermatocytes showed a reduction of the numbers of {gamma}-H2AX foci by 52% compared to 82% in the wild type, the difference being significant. However, after crossing over (in late pachytene and early diplotene), no effect of RAD54/RAD54B deficiency on the reduction of irradiation-induced foci was observed. In NHEJ deficient SCID mice, repair kinetics in early spermatocytes were similar to those in wild type mice. However, 1 h after irradiation in late pachytene and early diplotene spermatocytes 1.7 times more foci were found than in wild type mice. This difference might be related to the absence of a DNA-PKcs dependent fast repair component in SCID mice. As subsequent repair is normal, HR likely is taking over. Taken together, the results obtained in RAD54/RAD54B deficient mice and in SCID mice indicate that DSB repair in early pachytene spermatocytes is mainly carried out through HR. In late spermatocytes (late pachytenes and early diplotenes) NHEJ is active. However, probably there is an interplay between these repair pathways and when in late spermatocytes the NHEJ pathway is compromised HR may take over.

  6. Fusion bonding of carbon fabric reinforced polyphenylene sulphide

    OpenAIRE

    Degrieck J.; Van Paepegem W.; De Baere I.

    2011-01-01

    In recent years, there is a growing interest in joining techniques for thermoplastic composites as an alternative to adhesive bonding. In this manuscript, a fusion bonding process called hot-tool welding is investigated for this purpose and the used material is a carbon fabric reinforced polyphenylene sulphide. The quality of the welds is experimentally assessed using a short three-point bending setup, which has an interesting distribution of interlaminar shear stresses. It can be conc...

  7. Market presence in China strengthened Network growth and Dual-Chinese-Hub Strategy More frequet Flyer Benefit——Air China and shanhai Airlines Join Star Alliance

    Institute of Scientific and Technical Information of China (English)

    Audrey; Guo

    2008-01-01

      In the end of 2007, Air China Limited (hereinafter "Air China") and Shanghai Airlines, formally joined Star Alliance at a ceremony held in the new Terminal Three at Beijing Capital International Airport. With the addition of the two Chinese airlines, Star Alliance now has 19 member carriers operating 17,000 daily flights to 897 destinations in 160 countries.……

  8. Bond Issues.

    Science.gov (United States)

    Pollack, Rachel H.

    2000-01-01

    Notes trends toward increased borrowing by colleges and universities and offers guidelines for institutions that are considering issuing bonds to raise money for capital projects. Discussion covers advantages of using bond financing, how use of bonds impacts on traditional fund raising, other cautions and concerns, and some troubling aspects of…

  9. Joining of metal bars by a new process of transformation-diffusion brazing

    Institute of Scientific and Technical Information of China (English)

    Zhang Guifeng; Zhang Jianxun; Pei Yi

    2006-01-01

    Within the bonded interface of metal bars joint produced by conventional solid state bonding process (such as flash welding, resistance butt welding, friction welding and so on ), the inclusions are often present, which degrade the ductility of joint. A new process of transformation-diffusion brazing is proposed, in which an amorphous foil containing melting point depressant is preplaced between the interfaces to be joined, and the assembly is repeatedly heated/cooled without holding time at peak temperature. A low carbon steel bars, BNi-2 amorphous foil and resistance butt welding machine were used. The results show that surface contamination can be disrupted by the dissolution of base metal into molten interlayer in comparison with conventional process, and the ductility of joint can be improved by increasing the times of temperature cycles on line. In addition, transformation-diffusion brazing can be done with relatively simple and inexpensive system in comparison with transient liquid phase bonding.

  10. Theoretical Electron Density Distributions for Fe- and Cu-Sulfide Earth Materials: A Connection between Bond Length, Bond Critical Point Properties, Local Energy Densities, and Bonded Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, Gerald V.; Cox, David F.; Rosso, Kevin M.; Ross, Nancy L.; Downs, R. T.; Spackman, M. A.

    2007-03-01

    Bond critical point and local energy density properties together with net atomic charges were calculated for theoretical electron density distributions, F(r), generated for a variety of Fe and Cu metal-sulfide materials with high- and low-spin Fe atoms in octahedral coordination and high-spin Fe atoms in tetrahedral coordination. The electron density, F(rc), the Laplacian, 32F(rc), the local kinetic energy, G(rc), and the oxidation state of Fe increase as the local potential energy density, V(rc), the Fe-S bond lengths, and the coordination numbers of the Fe atoms decrease. The properties of the bonded interactions for the octahedrally coordinated low-spin Fe atoms for pyrite and marcasite are distinct from those for high-spin Fe atoms for troilite, smythite, and greigite. The Fe-S bond lengths are shorter and the values of F(rc) and 32F(rc) are larger for pyrite and marcasite, indicating that the accumulation and local concentration of F(r) in the internuclear region are greater than those involving the longer, high-spin Fe-S bonded interactions. The net atomic charges and the bonded radii calculated for the Fe and S atoms in pyrite and marcasite are also smaller than those for sulfides with high-spin octahedrally coordinated Fe atoms. Collectively, the Fe-S interactions are indicated to be intermediate in character with the low-spin Fe-S interactions having greater shared character than the highspin interactions. The bond lengths observed for chalcopyrite together with the calculated bond critical point properties are consistent with the formula Cu+Fe3+S2. The bond length is shorter and the F(rc) value is larger for the FeS4 tetrahedron displayed by metastable greigite than those displayed by chalcopyrite and cubanite, consistent with a proposal that the Fe atom in greigite is tetravalent. S-S bond paths exist between each of the surface S atoms of adjacent slabs of FeS6 octahedra comprising the layer sulfide smythite, suggesting that the neutral Fe3S4 slabs are

  11. Atoms in Valence Bond. Method, implementation and application

    NARCIS (Netherlands)

    Zielinski, M.L.

    2012-01-01

    The Atoms in Valence Bond (AiVB) approach is presented. The main goal was to develop a new and innovative approach, within the existing Valence Bond framework, to build and analyze the molecular VB wave function in terms of atoms and their atomic states, in a very user-friendly environment. The nece

  12. Resin-Bonded Bridges in vitro and in vivo

    NARCIS (Netherlands)

    Veen, Johannes Hilbrandt van der

    1988-01-01

    In this thesis in vitro and in vivo studies on the clinical application of resin-bonded bridges are described and discussed. The development of different types of resin-bonded bridges is described in chapter 1. The bridges are often made by boding a cast metal retainer fitted with and artificial too

  13. Transistor bonding pad configuration for uniform injection and low inductance

    Science.gov (United States)

    Jacobson, D. S.

    1970-01-01

    Modification of process for fabricating transistors, which comprises a metallization-pattern design for emitter and base areas together with a double bonding configuration for each emitter and base-bonding lead, improves uniformity of carrier injection in transistors and of reducing lead inductances at base-emitter terminals.

  14. Bond-Energy and Surface-Energy Calculations in Metals

    Science.gov (United States)

    Eberhart, James G.; Horner, Steve

    2010-01-01

    A simple technique appropriate for introductory materials science courses is outlined for the calculation of bond energies in metals from lattice energies. The approach is applied to body-centered cubic (bcc), face-centered cubic (fcc), and hexagonal-closest-packed (hcp) metals. The strength of these bonds is tabulated for a variety metals and is…

  15. 45 CFR 1309.23 - Insurance, bonding and maintenance.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Insurance, bonding and maintenance. 1309.23 Section 1309.23 Public Welfare Regulations Relating to Public Welfare (Continued) OFFICE OF HUMAN... of Federal Interest § 1309.23 Insurance, bonding and maintenance. (a) At the time of acquiring...

  16. Breastfeeding, Bonding, and the Mother-Infant Relationship.

    Science.gov (United States)

    Else-Quest, Nicole M.; Hyde, Janet Shibley; Clark, Roseanne

    2003-01-01

    Analyzed data from a longitudinal study of 570 mother-infant pairs to test the bonding hypothesis and the good-enough caregiver hypothesis as they relate to breastfeeding with maternal bonding and the mother-infant relationship. Found that breastfeeding dyads tended to show higher-quality relationships at 12 months than did bottle-feeding dyads.…

  17. Time- and temperature-dependent failures of a bonded joint

    Energy Technology Data Exchange (ETDEWEB)

    Sihn, Sangwook; Miyano, Yasushi; Tsai, S.W. [Stanford Univ., Palo Alto, CA (United States)

    1997-07-01

    Time and temperature dependent properties of a tubular lap bonded joint are reported. The joint bonds a cast iron rod and a composite pipe together with an epoxy type of an adhesive material containing chopped glass fiber. A new fabrication method is proposed.

  18. Oxytocin and mutual communication in mother-infant bonding

    Directory of Open Access Journals (Sweden)

    Miho eNagasawa

    2012-02-01

    Full Text Available Mother-infant bonding is universal to all mammalian species. In this review, we describe the manner in which reciprocal communication between the mother and infant leads to mother-infant bonding in rodents. In rats and mice, mother-infant bond formation is reinforced by various social stimuli, such as tactile stimuli and ultrasonic vocalizations from the pups to the mother, and feeding and tactile stimulation from the mother to the pups. Some evidence suggests that mother and infant can develop a cross-modal sensory recognition of their counterpart during this bonding process. Neurochemically, oxytocin in the neural system plays a pivotal role in each side of the mother-infant bonding process, although the mechanisms underlying bond formation in the brains of infants has not yet been clarified. Impairment of mother-infant bonding, that is, deprivation of social stimuli from the mother, strongly influences offspring sociality, including maternal behavior toward their own offspring in their adulthood, implying a non-genomic transmission of maternal environment, even in rodents. The comparative understanding of cognitive functions between mother and infants, and the biological mechanisms involved in mother-infant bonding may help us understand psychiatric disorders associated with mother-infant relationships.

  19. Bond length variation in hydronitride molecules and nitride crystals

    Science.gov (United States)

    Buterakos, L. A.; Gibbs, G. V.; Boisen, M. B.

    1992-08-01

    Bond lengths calculated for the coordination polyhedra in hydronitride molecules match average values observed for XN bonds involving main group X-cations in nitride crystals to within ˜0.04 Å. As suggested for oxide and sulfide molecules and crystals, the forces that determine the average bond lengths recorded for coordinated polyhedra in hydronitride molecules and nitride crystals appear to be governed in large part by the atoms that comprise the polyhedra and those that induce local charge balance. The forces exerted on the coordinated polyhedra by other parts of the structure seem to play a small if not an insignificant role in governing bond length variations. Bonded radii for the nitride ion obtained from theoretical electron density maps calculated for the molecules increase linearly with bond length as observed for nitride crystals with the rock salt structure. Promolecule radii calculated for the molecules correlate with bonded and ionic radii, indicating that the electron density distributions in hydronitride molecules possess a significant atomic component, despite bond type.

  20. Transition-Metal-Catalyzed C-H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds.

    Science.gov (United States)

    Hummel, Joshua R; Boerth, Jeffrey A; Ellman, Jonathan A

    2016-12-12

    The transition-metal-catalyzed addition of C-H bonds to carbonyls, imines, and related polarized π bonds has emerged as a particularly efficient and powerful approach for the construction of an incredibly diverse array of heteroatom-substituted products. Readily available and stable inputs are typically employed, and reactions often proceed with very high functional group compatibility and without the production of waste byproducts. Additionally, many transition-metal-catalyzed C-H bond additions to polarized π bonds occur within cascade reaction sequences to provide rapid access to a diverse array of different heterocyclic as well as carbocyclic products. This review highlights the diversity of transformations that have been achieved, catalysts that have been used, and types of products that have been prepared through the transition-metal-catalyzed addition of C-H bonds to carbonyls, imines, and related polarized π bonds.

  1. Treasury bond volatility and uncertainty about monetary policy

    NARCIS (Netherlands)

    Arnold, I.J.M.; Vrugt, E.B.

    2010-01-01

    We show that dispersion-based uncertainty about the future course of monetary policy is the single most important determinant of Treasury bond volatility across all maturities. The link between Treasury bond volatility and uncertainty about macroeconomic variables is much stronger than for the more

  2. Bonding Energy and Growth Habit of Lithium Niobate Single Crystals

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    On the basis of crystallographic structure of lithium niobate (LN), the bonding energy was quantitatively calculated by the bond valence sum model, which was employed to investigate the crystal growth. A possible relationship between the crystal growth habit and chemical bonding energy of LN crystals are found. It is found that the higher the bond energy, the slower the growth rate, and the more important the plane. The analytical results indicate that (012) plane is the most influential face for the LN crystal growth, which consists well with the standard card (JCPDS Card: 20-0631) and our previous experimental observation. The current work shows that the chemical bond analysis of LN crystals allows us to predict its growth habit and thus to obtain the expected morphology during the spontaneous growth.

  3. Electrostatically enhanced FF interactions through hydrogen bonding, halogen bonding and metal coordination: an ab initio study.

    Science.gov (United States)

    Bauzá, Antonio; Frontera, Antonio

    2016-07-27

    In this manuscript the ability of hydrogen and halogen bonding interactions, as well as metal coordination to enhance FF interactions involving fluorine substituted aromatic rings has been studied at the RI-MP2/def2-TZVPD level of theory. We have used 4-fluoropyridine, 4-fluorobenzonitrile, 3-(4-fluorophenyl)propiolonitrile and their respective meta derivatives as aromatic compounds. In addition, we have used HF and IF as hydrogen and halogen bond donors, respectively, and Ag(i) as the coordination metal. Furthermore, we have also used HF as an electron rich fluorine donor entity, thus establishing FF interactions with the above mentioned aromatic systems. Moreover, a CSD (Cambridge Structural Database) search has been carried out and some interesting examples have been found, highlighting the impact of FF interactions involving aromatic fluorine atoms in solid state chemistry. Finally, cooperativity effects between FF interactions and both hydrogen and halogen bonding interactions have been analyzed and compared. We have also used Bader's theory of "atoms in molecules" to further describe the cooperative effects.

  4. Recombination events near the immunoglobulin Cmu gene join variable and constant region genes, switch heavy-chain expression, or inactivate the locus.

    Science.gov (United States)

    Cory, S; Webb, E; Gough, J; Adams, J M

    1981-04-28

    Immunoglobulin heavy-chain expression is initiated by recombination between a variable region (VH) gene and one of several joining region (JH) genes located near the mu constant region (Cmu) gene, and the active VH gene can subsequently switch to another CH gene. That the general mechanism for CH switching involves recombination between sites within the JH-Cmu intervening sequence and the 5' flanking region of another CH gene is supported here by Southern blot hybridization analysis of eight IgG- and IgA-secreting plasmacytomas. An alternative model requiring successive VH linkage to similar JH clusters near each CH gene is shown to be very unlikely since the mouse genome appears to contain only one complement of the JH locus and no JH gene was detectable within large cloned sequences flanking germline C gamma 3 and C gamma 1 genes. Thus, VH-JH joining and CH switching are mediated by separate regions of "the joining-switch" or J-S element. In each plasmacytoma examined, the J-S element had undergone recombination within both the JH locus and the switch region and was shown to be linked to the functional CH gene in an IgG3, and IgG1, and three IgA secretors. Both JH joining and CH switching occurred by deletion of DNA. Switch recombination occurred at more than one site within the J-S element in different lines, even for recombination with the same CH gene. Significantly, although heavy-chain expression is restricted to one allele ("allelic exclusion"), all rearranged in each plasmacytoma. Some rearrangements were aberrant, involving, for example, deletion of all JH genes from the allele. Hence, an error-prone recombination machinery may account for allelic exclusion in many plasmacytomas.

  5. Effects of dentin depth and cavity configuration on bond strength.

    Science.gov (United States)

    Yoshikawa, T; Sano, H; Burrow, M F; Tagami, J; Pashley, D H

    1999-04-01

    During polymerization of resin composites, shrinkage stresses compete with resin-dentin bonds in a manner that can cause failure of the bond, depending upon the configuration of the cavity, its depth, and the restorative technique. The hypothesis tested in this study was that the effect of cavity configuration (C) and remaining dentin thickness (RDT) influence resin bond strength to the dentin of Class I cavity floors. The occlusal enamel was ground to expose a flat superficial dentin surface as a control (superficial dentin, C-factor = 1) in human extracted third molars. Cavities 3 mm long x 4 mm wide were prepared to a depth 2 mm below the ground dentin surfaces (deep dentin within cavity floor, C-factor = 3). To assess the relationship between C-factor and RDT, we removed the walls of cavities, making a deep flat surface for bonding (deep dentin, C-factor = 1). The teeth were restored with either Clearfil Liner Bond II (LB II), One-Step (OS), or Super-Bond D Liner (DL), followed by Clearfil Photo Posterior resin composite. After 24 hrs' storage in water, the teeth were sectioned vertically into 3 or 4 slabs (0.7 mm thick) and trimmed for the micro-tensile bond test so that we could determine the strength of the resin bonds to the pulpal floor. All groups gave high bond strengths to superficial dentin, but OS and DL gave significantly lower bond strengths to flat deep dentin when the C-factor was 1. When the C-factor was increased to 3 by the creation of a three-dimensional cavity preparation, the bond strengths of all materials fell (range, 21 to 35%), but the difference was significant (p bond strengths tended to exhibit cohesive failures within the hybrid layer, while specimens exhibiting low bond strengths showed failures at the top of the hybrid layer. Some adhesives do not bond well to deep dentin, making them more susceptible to polymerization shrinkage stress that develops in cavities with high C-factors.

  6. The comovement of US and German bond markets

    DEFF Research Database (Denmark)

    Engsted, Tom; Tanggaard, Carsten

    2007-01-01

    then cross-country correlate these news components to see which component is responsible for the high degree of comovement of US and German bond markets. For the period 1975-2003 we find that inflation news is the main driving force behind this comovement. When news is coming to the US market that future US...... inflation will increase, there is a tendency that German inflation will also increase. This is regarded bad news for the bond market in both countries whereby bond prices are bid down leading to immediate negative return innovations and changing expectations of future excess bond returns. Thus, comovement...... in expected future inflation is the main reason for bond market comovement....

  7. Ni/Al Multilayers Produced by Accumulative Roll Bonding and Sputtering

    Science.gov (United States)

    Simões, S.; Ramos, A. S.; Viana, F.; Emadinia, O.; Vieira, M. T.; Vieira, M. F.

    2016-10-01

    Ni/Al multilayers are known to transform into NiAl in a highly exothermic and self-sustaining reaction. The fact that this reaction has a high heat release rate and can be triggered by an external impulse, are reasons why it has already attracted much research attention. There is a huge potential in the use of Ni/Al multilayers as a controllable and localized heat source for joining temperature-sensitive materials such as microelectronic components. The heat released and the phases resulting from the reaction of Ni and Al multilayers depend on the production methods, their composition, as well as the bilayer thickness and annealing conditions. The present research aims to explore the influence of these variables on the reaction of different multilayers, namely those produced by accumulative roll bonding (ARB) and sputtering. Structural evolution of Ni/Al multilayers with temperature was studied by differential scanning calorimetry, x-ray diffraction and scanning electron microscopy. Phase evolution, heat release rate and NiAl final grain size are controlled by the ignition method used to trigger the reaction of Ni and Al. The potential use of these multilayers in the diffusion bonding of TiAl was analyzed. The ARB multilayers allow the production of joints with higher strength than the joints produced with commercial multilayers (NanoFoil®) produced by sputtering. However, the formation of brittle intermetallic phases (Ni3Al, Ni2Al3 and NiAl3) compromises the mechanical properties of the joint.

  8. Rad51 and RecA juxtapose dsDNA ends ready for DNA ligase-catalyzed end-joining under recombinase-suppressive conditions.

    Science.gov (United States)

    Konomura, Naoto; Arai, Naoto; Shinohara, Takeshi; Kobayashi, Jun; Iwasaki, Wakana; Ikawa, Shukuko; Kusano, Kohji; Shibata, Takehiko

    2017-01-09

    RecA-family recombinase-catalyzed ATP-dependent homologous joint formation is critical for homologous recombination, in which RecA or Rad51 binds first to single-stranded (ss)DNA and then interacts with double-stranded (ds)DNA. However, when RecA or Rad51 interacts with dsDNA before binding to ssDNA, the homologous joint-forming activity of RecA or Rad51 is quickly suppressed. We found that under these and adenosine diphosphate (ADP)-generating suppressive conditions for the recombinase activity, RecA or Rad51 at similar optimal concentrations enhances the DNA ligase-catalyzed dsDNA end-joining (DNA ligation) about 30- to 40-fold. The DNA ligation enhancement by RecA or Rad51 transforms most of the substrate DNA into multimers within 2-5 min, and for this enhancement, ADP is the common and best cofactor. Adenosine triphosphate (ATP) is effective for RecA, but not for Rad51. Rad51/RecA-enhanced DNA ligation depends on dsDNA-binding, as shown by a mutant, and is independent of physical interactions with the DNA ligase. These observations demonstrate the common and unique activities of RecA and Rad51 to juxtapose dsDNA-ends in preparation for covalent joining by a DNA ligase. This new in vitro function of Rad51 provides a simple explanation for our genetic observation that Rad51 plays a role in the fidelity of the end-joining of a reporter plasmid DNA, by yeast canonical non-homologous end-joining (NHEJ) in vivo.

  9. Microwave joining of SiC

    Energy Technology Data Exchange (ETDEWEB)

    Silberglitt, R.; Ahmad, I. [FM Technologies, Inc., Fairfax, VA (United States); Black, W.M. [George Mason Univ., Fairfax, VA (United States)] [and others

    1995-05-01

    The purpose of this work is to optimize the properties of SiC-SiC joints made using microwave energy. The current focus is on optimization of time-temperature profiles, production of SiC from chemical precursors, and design of new applicators for joining of long tubes.

  10. Dividends Sharing Convertible Bonds Pricing and Numerical Evaluation

    Directory of Open Access Journals (Sweden)

    Xu Guo

    2013-01-01

    Full Text Available The convertible bond is becoming one of the most important financial instruments for the company to raise capital fund since it was first issued by American New York Erie Company in 1843. In this paper, it is the first time to study the pricing problem for convertible bond whose underlying stocks pay dividends via the reflected backward stochastic differential equations. Associating the solutions of reflected BSDEs with the obstacle problems for nonlinear parabolic PDEs, we establish the pricing formulas for convertible bonds with continuous and discrete dividends by means of the viscosity solutions for some PDEs. Besides, we also derive the price of convertible bonds with higher borrowing rate which is realistic in the financial market. Then the numerical evaluations are provided by the radial basis functions method. Moreover, we discuss the influence of dividends paying as well as higher borrowing rate on the convertible bond price at last.

  11. Summary of Prior Work on Joining of Oxide Dispersion-Strengthened Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Ian G [ORNL; Tatlock, Gordon J [ORNL; Badairy, H. [University of Liverpool; Chen, C-L. [University of Liverpool

    2009-08-01

    There is a range of joining techniques available for use with ODS alloys, but care should be exercised in matching the technique to the final duty requirements of the joint. The goal for joining ODS alloys is a joint with no local disruption of the distribution of the oxide dispersion, and no significant change in the size and orientation of the alloy microstructure. Not surprisingly, the fusion welding processes typically employed with wrought alloys produce the least satisfactory results with ODS alloys, but some versions, such as fusion spot welding, and the laser and electron-beam welding technologies, have demonstrated potential for producing sound joints. Welds made using solid-state spot welding reportedly have exhibited parent metal properties. Thus, it is possible to employ processes that result in significant disruption of the alloy microstructure, as long as the processing parameters are adjustment to minimize the extent of or influence of the changes in the alloy microstructure. Selection among these joining approaches largely depends on the particular application and component configuration, and an understanding of the relationships among processing, alloy microstructure, and final properties is key. Recent developments have resulted in friction welding evolving to be a prime method for joining ODS sheet products, and variants of brazing/diffusion bonding have shown excellent promise for use with tubes and pipes. The techniques that come closest to the goal defined above involve solid-state diffusion bonding and, in particular, it has been found that secondary recrystallization of joints made by pulsed plasma-assisted diffusion can produce the desired, continuous, large alloy grain structure through the joint. Such joints have exhibited creep rupture failure at >82% of the load needed to fail the monolithic parent alloy at 1000 C.

  12. Bonding and Anti-bonding Modes of Plasmon Coupling Effects in TiO2-Ag Core-shell Dimers

    Science.gov (United States)

    Li, Quanshui; Zhang, Zhili

    2016-01-01

    Bonding and anti-bonding modes of plasmon coupling effects are numerically investigated in TiO2-Ag core-shell nano dimers. First, splitting phenomena of the coupled anti-bonding modes are observed under the longitudinal polarization when the distance between the monomers decreases to a certain level. Second, one of the split resonance modes is identified to be formed by the dipole anti-bonding mode of the monomers from charge density distribution patterns. Those split modes have similar redshift behaviors as the coupled dipole bonding modes in the same situations. Furthermore, the intensities of those anti-bonding modes weaken with decreasing distance between the monomers, because of the interaction of the induced dipole moment in the monomers and the charge distribution variation on the facing surfaces of the gap by the coulomb attraction. Other split bands are the higher-order mode (octupole-like or triakontadipole-like), which do not have obvious peak-shift behavior, and the intensities have very little attenuation with decreasing distance. Finally, the coupling of the bonding and anti-bonding modes under the longitudinal polarization is symmetric (bonding).

  13. Bonding and Anti-bonding Modes of Plasmon Coupling Effects in TiO2-Ag Core-shell Dimers

    OpenAIRE

    Quanshui Li; Zhili Zhang

    2016-01-01

    Bonding and anti-bonding modes of plasmon coupling effects are numerically investigated in TiO2-Ag core-shell nano dimers. First, splitting phenomena of the coupled anti-bonding modes are observed under the longitudinal polarization when the distance between the monomers decreases to a certain level. Second, one of the split resonance modes is identified to be formed by the dipole anti-bonding mode of the monomers from charge density distribution patterns. Those split modes have similar redsh...

  14. Diffusion-bonded beryllium aluminum optical structures

    Science.gov (United States)

    Grapes, Thomas F.

    2003-12-01

    Beryllium aluminum material can present significant advantages for optical support structures. A likely advantage of beryllium aluminum compared to aluminum or titanium for such structures is its higher specific stiffness. However, beryllium aluminum material is significantly more expensive than most competing materials. The cost problem with beryllium aluminum is exacerbated if fabrication methods that result in near net shape parts are not used. Near net shape methods result in the least amount of material "thrown away" in the fabrication process. Casting is a primary example of near net shape manufacturing that is appropriate for some optical support structures. Casting aluminum, and other materials as well, is common. Casting of beryllium aluminum is very difficult, however, and has not had significant success. Diffusion bonding - a different approach for achieving near net shape beryllium aluminum optical support structures, was pursued and accomplished. Diffusion bonding is a term used to describe the joining of solid metal pieces under high temperature and pressure, but without melting. Three different optical support structures were designed and built of beryllium aluminum using diffusion bonding. Relatively small solid beryllium aluminum pieces were arranged together and then joined under hot isostatic pressure conditions. The resulting relatively large pressure bonded part was then machined to achieve the final product. Significant cost savings as compared to machining the part from a solid block were realized. Difficulties achieving diffusion bonds in complex joints were experienced and addressed.

  15. "We Provide You the Right Cooperators!"-- Cotton Council International and Cotton Incorporated Join Hands to Participate in 2012 Intertextile Shanghai Apparel Fabrics%"We Provide You the Right Cooperators!"-- Cotton Council International and Cotton Incorporated Join Hands to Participate in 2012 Intertextile Shanghai Apparel Fabrics

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    During the Intertextile Shanghai Apparel Fabrics (China International Trade Fair for Apparel Fabrics and Accessories), which was held from October 22 to 25, 2012, Cotton Council International (COl) and Cotton Incorporated (Cl) joined forces with Central Fabrics Company Limited and Sanyang Textile Company Limited - both "COTTON USA" licensees - to promote U.S. cotton.

  16. Alojamiento conjunto madre-hijo y lactancia humana exclusiva Joined mother-child hospital lodging and exclusive human lactation

    Directory of Open Access Journals (Sweden)

    SAMUEL FLORES-HUERTA

    1997-03-01

    Full Text Available Objetivo. Conocer la influencia del alojamiento conjunto (AC madre-hijo, en la frecuencia de lactancia humana exclusiva (LHE, desde el nacimiento hasta los cuatro meses de vida. Material y métodos. Estudio de cohortes no aleatorizado realizado en la clínica de lactancia del Hospital "Luis Castelazo Ayala", del Instituto Mexicano del Seguro Social, de enero de 1993 a octubre de 1994, en el que participaron 178 binomios madre-hijo (BMH sanos con gestación de término. El grupo con alojamiento conjunto (AC se integró con 90 BMH, y la madre recibió asesoría para lactar; 88 se atendieron en forma separada, sin asesoría para lactar. Se realizó análisis estadístico de los datos para apreciar frecuencia y asociaciones de las variables. Resultados. La alimentación se registró como LHE, fórmula o ambas. Los grupos con y sin AC se estratificaron por la forma de nacimiento, parto o cesárea. Con X² de Mantel-Haenszel y de rango logarítmico se aceptaron diferencias con pObjective. To determine the influence of joined mother-child hospital lodging (JL on the frequency of exclusive human lactation (EHL from birth to four months of age. Material and methods. Non-randomized cohort study performed at the lactation clinic of the "Luis Castelazo Ayala" Hospital of the Mexican Social Security Institute from January 1993 to October 1994 which included 178 healthy mother-child pairs (MCP with term pregnancy. The jointly lodged group (JL consisted of 90 MCP in which mothers received assessment for lactation; 88 MCP were lodged separately and no assessment was provided. Results were statistically analyzed to determine frequency and variable associations. Results. Feeding was recorded as either EHL, powdered milk or both. Groups with or without JL were stratified by form of birth, either labor or Cesarean section. With the Mantel-Haenszel X² and logarithmic range, differences were significant with p<0.05. During the study, global lactation was similar

  17. Valence-Bond Concepts in Coordination Chemistry and the Nature of Metal-Metal Bonds.

    Science.gov (United States)

    Pauling, Linus; Herman, Zelek S.

    1984-01-01

    Discusses the valence-bond method, applying it to some coordination compounds of metals, especially those involving metal-metal bonds. Suggests that transition metals can form as many as nine covalent bonds, permitting valence-theory to be extended to transition metal compounds in a more effective way than has been possible before. (JN)

  18. Love and attachment: the psychobiology of social bonding.

    Science.gov (United States)

    Stein, Dan J; Vythilingum, Bavanisha

    2009-05-01

    Basic animal studies and human imaging studies have contributed to our understanding of the psychobiology of love and attachment. There are overlaps and distinctions in the neuronal circuitry of maternal love, romantic love, and long-term attachment. In these circuits, important molecules, which have been demonstrated to play a role in the psychobiology of social bonding include dopamine, serotonin, opioids, oxytocin, and vasopressin. Particular genetic and environmental variations contribute to social-bonding phenotypes, consistent with an evolutionary perspective on the value of these behaviors. Advances in the psychobiology of social bonds have led to hypotheses about the pharmacotherapy of disorders of attachment.

  19. The Nature of Bonding in WC and WN

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The nature of bonding in the title compounds has been studied by using CASSCF and FOCl techniques. The ground states of WC and WN are found to be 3Δ and 4∑- state arising primarily from:...1σ2σ21π41δ13σ1 and ...1σ2σ21π41δ23σ1 configuration respectively. WC shows a strong character of covalent bond while WN have obvious character of ionic bond and the dissociation energy of WN is larger than that of WC (6.15 and 5.41 eV respective).

  20. Transient liquid phase bonding of a third generation gamma-titanium aluminum alloy: Gamma Met PX

    Science.gov (United States)

    Butts, Daniel A.

    The research work presented here discusses transient liquid phase (TLP) bonding of a current (i.e. third) generation gamma-TiAl alloy known as Gamma Met PX (GMPX). Effective implementation of GMPX in service is likely to require fabrication of complicated geometries for which a high performance metallurgical joining technique must be developed. Although a number of joining processes have been investigated, all have significant disadvantages that limit their ability to achieve sound joints. TLP bonding has proved to be a successful method of producing joints with microstructures and compositions similar to that of the bulk substrates. Hence, bonds with parent-like mechanical and oxidation properties are possible. The interlayer and bonding conditions employed for joining of GMPX were based on successful wide-gap TLP joining trials of an earlier generation cast gamma-TiAl alloy with a composition of Ti-48Al-2Cr-2Nb in atomic percent (abbreviated here to 48-2-2). A composite interlayer consisting of a 6:1 weight ratio (7 vol.% copper) of gas atomized 48-2-2 powders (-270 mesh) and pure copper powders (-325 mesh) was employed. When applied to GMPX, these interlayer ratio and bonding conditions produced undesirable microstructures and poor mechanical performance in as-bonded joints. Thus, modifications to the joining technique were required. Initially these modifications were based purely on empirical and phenomenological studies, however, detailed mechanistic studies of the underlying joining mechanisms were conducted to aid in selecting these modifications. Mechanisms such as diffusion, solubility and wettability of copper in/on GMPX and 48-2-2 bulk substrates were investigated and compared. A difference in solubility of copper in GMPX and 48-2-2 bulk substrates was attributed to (at least in part) to the observed differences in GMPX and 48-2-2 bonds. The copper solubility, at the bonding temperature, in the 48-2-2 and GMPX alloys was determined to be ˜2 at.% and ˜1