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Sample records for divider plate bolt

  1. Stiffness Analysis and Improvement of Bolt-Plate Contact Assemblies

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Pedersen, Pauli

    2008-01-01

    In a previous study it was shown that, a simplified expression for the stiffness of the plate member in a bolt-plate assembly can be found. The stiffnesses of the bolt and the connected plates are the primary quantities that control the lifetime of a dynamically loaded connection. The present study...... of stiffnesses is extended to include different material parameters by including the influence of Poisson's ratio. Two simple practical formulas are suggested and their accuracies are documented for different bolts and different material (Poisson's ratio). Secondly, the contact analysis between the bolt head...... and the plate is extended by the possibility of designing a gap, that is, a nonuniform distance between the bolt and plate before prestressing. Designing the gap function generates the possibility for a better stress field by which the stiffness of the bolt is lowered, and at the same time the stiffness...

  2. Anchor Bolt Position in Base Plate In Terms Of T and J Anchor Bolt

    Directory of Open Access Journals (Sweden)

    b Osman Mohamad Hairi

    2017-01-01

    Full Text Available Generally, L anchor bolt system has been used for a long period of time in construction industry as one of the distributing load structures. However, there are some weaknesses in L anchor bolt which may straighten and pullup when charged with tensile load. Current practices prefer to use other types of anchor bolt systems, such as headed studs anchor bolt system to replace the L anchor bolt design. There has been lack of studies to prove that it is more effective in terms of performance. A new T anchor bolt which was basically modified from headed studs anchor bolt was proposed in this study to compare its performance of tensile loading in concrete failure to typical L design. This study aims to determine whether the T anchor bolt system gives better performance as compared to an L anchor bolt system. The performance was rated based on tensile loading on concrete failure pattern. A pullout test was conducted on two different anchor bolt systems, namely L and T. The anchor bolt embedded depth, h in concrete were varied according to their hook or bend radius. Each sample was repeated twice. There were totally eight samples. The hook or bend radius used were 50 mm and 57.5 mm for sample L1 and L2, respectively. 90-degree bend were used on sample T1 and T2. Based on test results, it can be seen that the performance of concrete failure pattern under tensile load on both L and T anchor bolt design samples with 200 mm embedment depth was better than deeper embedment depth of 230 mm. But the L anchor bolt design gives the best results as compared to T design. Although T anchor bolt design shows higher resistance before first bond failure to the concrete sample. T anchor bolt was analysed and needed deeper embedment depth to allow formation of cone pull-out shape to acquire better performance.

  3. A load measuring anchor plate for rock bolt using fiber optic sensor

    Science.gov (United States)

    Ho, Siu Chun Michael; Li, Weijie; Wang, Bo; Song, Gangbing

    2017-05-01

    Rock bolts are the devices that used to reinforce the rock masses in mining tunnels and underground excavation structures. The loading level of the rock bolt indicates the reinforcing efficiency and is able to ensure safe underground operation by giving warnings to the underground miners prior to any accidents. Therefore, it is very important to monitor the load level of the rock bolts. In this short communication, we propose a smart anchor plate, a simple but effective device that uses fiber Bragg gratings (FBG) type optic sensor, to monitor the load level of the rock bolt. Instead of measuring the stress/strain on the rock bolt, which adds more complexity, the proposed method monitors the rock bolt load by measuring the load experience on the rock bolt anchor plate. Such a configuration has the advantages of simple structure and flexible implementation. In experimental observation, the FBG instrumented anchor plate is able to observe the load of the plate with good repeatability. This test will lead to further in-depth studies involving finite element analysis as well as more complex applications.

  4. Experimental and Numerical Investigation of an End Plate Connection with Using Long Shank SMA Bolts

    Institute of Scientific and Technical Information of China (English)

    Hongwei Ma; Yongbing Zhu; Michael CH Yam; Yang Wang

    2015-01-01

    Superelastic shape memory alloys ( SMAs ) have the ability to recover their original shape after experiencing large strains. End⁃plate connection with using superelastic long shank SMA bolts is proposed in this paper. By using strong beam⁃weak bolt cluster design methodology and special configurations to strength beam ends, a superelastic hinge is expected to form in column flange. To validate the mechanical behavior of the proposed beam⁃to⁃column connection, both quasi⁃static tests and numerical analysis are conducted with cyclic transverse loads applied on the beam ends. The results indicate the connection deformations concentrate on the long shank SMA bolts upon loading and the bolt cluster rotates around the axis near beam flange. By using the super elastic effect, the SMA bolts recover most elongations and the connection recovers to its original shape after experiencing 0�02 rad interstorey drift angle. The connection shows obvious self⁃centering properties.

  5. On prestress stiffness analysis of bolt-plate contact assemblies

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Pedersen, Pauli

    2008-01-01

    Bolt connections are among the most important connections used in structures. The stiffnesses of the bolt and of the connected members are the primary qualities that control the lifetime of the connection. The stiffness of the bolt can be estimated rather easily, in contrast to the member stiffness......, but with finite element (FE) and contact analysis, it is possible to find the stiffness of the member. In the case of many connections and for practical applications, it is not suitable to make a full FE analysis. The purpose of the present paper is to find simplified expressions for the stiffness of the member......, including the case when the width of the member is limited. The calculation of the stiffness is based on the FE, including the solution to the contact problem, and we express the stiffness as a function of the elastic energy in the structure, whereby the definition of the displacements related...

  6. Thermal Performance Evaluation of Friction Stir Welded and Bolted Cold Plates with Al/Cu Interface

    Science.gov (United States)

    Lakshminarayanan, A. K.; Suresh, M.; Sibi Varshan, M.

    2015-05-01

    An attempt is made to design and fabricate a cold plate with aluminum-copper dissimilar interface joined by friction stir welding. Optimum welding conditions for obtaining sound-quality corner and T joints with an aluminum-copper interface were established. Welded cross sections of the friction stir welded cold plate were analyzed to understand the bonding characteristics. Computational fluid dynamics (CFD) was used to evaluate the fluid-flow characteristics and thermal resistance of friction stir welded cold plate and the resulted are compared with the conventional bolted cold plate configuration. For CFD modeling of a cold plate with a dissimilar interface, a new methodology is proposed. From the CFD analysis and experimental results, it is observed that friction stir welded cold plate offered better thermal performance compared to the bolted cold plate and it is due to the metallurgical bonding at the aluminum-copper interface with the dispersion of copper particles.

  7. Using plate mapping to examine portion size and plate composition for large and small divided plates.

    Science.gov (United States)

    Sharp, David E; Sobal, Jeffery; Wansink, Brian

    2014-12-01

    Does the size of a plate influence the serving of all items equally, or does it influence the serving of some foods - such as meat versus vegetables - differently? To examine this question, we used the new method of plate mapping, where people drew a meal on a paper plate to examine sensitivity to small versus large three-compartment divided plates in portion size and meal composition in a sample of 109 university students. The total drawn meal area was 37% bigger on large plates than small plates, which showed that the portion of plate coverage did not differ by plate size. Men and women drew bigger vegetable portions and men drew bigger meat portions on large plates when compared to small plates. These results suggest that men and women are differentially sensitive to plate size for overall meal size and for meal composition. Implications for decreasing portion size and improving meal balance are that plate size may influence portion size and change the proportions of foods served.

  8. Fatigue Property of Open-Hole Steel Plates Influenced by Bolted Clamp-up and Hole Fabrication Methods

    Directory of Open Access Journals (Sweden)

    Zhi-Yu Wang

    2016-08-01

    Full Text Available Steel plates with open holes are commonly used in structural assemblies. The fatigue properties of such details are influenced by bolted clamp-up and hole fabrication methods. The fracture surface, stiffness degradation and fatigue life of test specimens are investigated in detail and compared with the contemporary test data. The analysis results show that the presence of draglines greatly influences the fatigue crack initiation at the open-hole cut by laser. The bolted clamp-up condition greatly enhances the stiffness and the fatigue life of the open-hole details. A discussion is also made from a comparison with the referred fatigue life of hole fabrication details, such as the influence of plate thickness and plasma cutting, drilling and oxy-fuel gas cutting, with the details studied herein. This work could enhance the understanding of the fatigue property and design of such details.

  9. Contact Stress Analysis around Elliptical Bolt-loaded Hole in Orthotropic Plates

    Directory of Open Access Journals (Sweden)

    O. Aluko

    2012-12-01

    Full Text Available The practicality of changing the bolt shape from circular to elliptical under friction effects in order to reduce the contact stress distributions was analytically investigated. The analysis utilized the complex stress functions obtained from the assumed displacement expressions that satisfy the boundary conditions around the hole to determine the contact stresses. In the method of solution coulomb friction was used to determine the prescribed displacements at the boundary. The material properties of graphite/epoxy and carbon fiber reinforced plastics laminates were used in this investigation and the results compared with available literature. It was revealed that the stress distributions followed the same pattern in both geometries but with lower magnitude in elliptical shape and the reduction in stress distributions caused by changing the bolt shape from circular to elliptic depend on friction coefficient.

  10. Bolting applications

    Energy Technology Data Exchange (ETDEWEB)

    Czajkowski, C J

    1984-05-01

    An investigation of bolting practices specific to the nuclear industry was performed. The report covered a large spectrum of topics e.g. bolts embedded in concrete, specifications, inspection of bolting, both at receipt and inservice. Plots of preload versus yield strength for different bolting materials in different environments are presented as well as information relative to the stress corrosion cracking resistance of the more recent reactor internals bolting materials A286 and Inconel X-750. Part of the report contains input by Standard Pressed Steel Inc. (a bolting consultant) relative to bolting standards, cottering methods and potential areas for bolting improvement.

  11. Bolt load simulation and its practical application

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, P.G.; Hume, B.G.; Hume, R.G. [Barrett Fuller and Partners, Melbourne, Vic. (Australia)

    1996-12-31

    The large range of rock bolting options now available makes choosing the best system for any given environment increasingly difficult. Bolt performance is highly dependent on the type of bolt used, the properties of the resin or grout, the plate type and the rock condition. The use of pre-tensioning or the presence of unbounded zones along the bolt provides further complications. The program BoltCalc has been developed to model the loads generated within bolts by rock mass displacements. The operation of the program is outlined and a series of examples illustrating the effects of various factors on bolt performance is presented. 1 ref., 11 figs.

  12. Hypospadias: the release of chordee without dividing the urethral plate and onlay island flap (92 cases)

    Science.gov (United States)

    Mollard, P; Castagnola, C

    1994-10-01

    Standard teaching states that the correction of fibrous chordee requires division of the urethral plate. Subsequently, it is necessary to reconstruct the urethra using tubular urethroplasty, which carries a significant incidence of complications, for example stenosis. In fact, we have demonstrated that it is possible to release severe chordee associated with hypospadias simply by dissecting the urethral plate of the corpora rather than dividing it. Between 1989 and 1993 we operated on 101 patients with hypospadias with fibrous chordee. The release of chordee was achieved without dividing the plate in 92 patients (91%), including all 71 cases of penile hypospadias, 11 perineal hypospadias and 10 reoperations. A total of 92 urethroplasties was performed with an onlay flap and 19 complications occurred in 15 patients.

  13. Cause Analysis and Improvement of Fracture Bolts on the Pipe Plate of Floating Head Type Heat Exchanger%浮头式热交换器浮头管板螺栓断裂原因分析及改进

    Institute of Scientific and Technical Information of China (English)

    陈彩霞; 赵青

    2014-01-01

    通过扫描电镜观察、硬度测试、化学成分分析及金相检验等方法分析了浮头式热交换器浮头管板连接螺栓的断裂失效原因。结果表明,硫化物应力腐蚀开裂、氢致开裂和螺纹加工产生应力集中、材料硬度不满足湿硫化氢介质中的使用要求是螺栓断裂的主要原因。%Fracture analysis of the bolts on the pipe plate of floating head type heat exchanger was conducted by means of scanning electron microscopy (SEM ) ,energy dispersive spectrometer (EDS) ,hardness test ,chemical analysis and metallographic examination etc .The results showed that the sulfide stress corrosion cracking (SSCC ) and hydrogen induced cracking (HIC ) is the main reason for the bolts fracture .The thread processing stress concentration ,the mismatch be-tween the H2 S medium on the material hardness requirements and the used material finally caused the bolts fracture .

  14. Behavior of Fiber Glass Bolts, Rock Bolts and Cable Bolts in Shear

    Science.gov (United States)

    Li, Xuwei; Aziz, Naj; Mirzaghorbanali, Ali; Nemcik, Jan

    2016-07-01

    This paper experimentally compares the shear behavior of fiber glass (FG) bolt, rock bolt (steel rebar bolt) and cable bolt for the bolt contribution to bolted concrete surface shear strength, and bolt failure mode. Two double shear apparatuses of different size were used for the study. The tensile strength, the shear strength and the deformation modulus of bolt control the shear behavior of a sheared bolted joint. Since the strength and deformation modulus of FG bolt, rock bolt and cable bolt obtained from uniaxial tensile tests are different, their shear behavior in reinforcing joints is accordingly different. Test results showed that the shear stiffness of FG bolted joints decreased gradually from the beginning to end, while the shear stiffness of joints reinforced by rock bolt and cable bolt decreased bi-linearly, which is clearly consistent with their tensile deformation modulus. The bolted joint shear stiffness was highly influenced by bolt pretension in the high stiffness stage for both rock bolt and cable bolt, but not in the low stiffness stage. The rock bolt contribution to joint shear strength standardised by the bolt tensile strength was the largest, followed by cable bolts, then FG bolts. Both the rock bolts and cable bolts tended to fail in tension, while FG bolts in shear due to their low shear strength and constant deformation modulus.

  15. Piezoelectric Bolt Breakers and Bolt Fatigue Testers

    Science.gov (United States)

    Sherrit, Stewart; Badescu, Mircea; Bar-Cohen, Yoseph; Barengoltz, Jack; Heckman, Vanessa

    2008-01-01

    A proposed family of devices for inducing fatigue in bolts in order to break the bolts would incorporate piezoelectric actuators into resonant fixtures as in ultrasonic/ sonic drills/corers and similar devices described in numerous prior NASA Tech Briefs articles. These devices were originally intended primarily for use as safer, more-reliable, more-versatile alternatives to explosive bolts heretofore used to fasten spacecraft structures that must subsequently be separated from each other quickly on command during flight. On Earth, these devices could be used for accelerated fatigue testing of bolts. Fatigue theory suggests that a bolt subjected to both a constant-amplitude dynamic (that is, oscillatory) stress and a static tensile stress below the ultimate strength of the bolt material will fail faster than will a bolt subjected to only the dynamic stress. This suggestion would be applied in a device of the proposed type. The device would be designed so that the device and the bolt to be fatigue-tested or broken would be integral parts of an assembly (see figure). The static tension in the tightened bolt would apply not only the clamping force to hold the joined structures (if any) together but also the compression necessary for proper operation of the piezoelectric actuators as parts of a resonant structural assembly. The constant-amplitude dynamic stress would be applied to the bolt by driving the piezoelectric actuators with a sinusoidal voltage at the resonance frequency of longitudinal vibration of the assembly. The amplitude of the excitation would be made large enough so that the vibration would induce fatigue in the bolt within an acceptably short time. In the spacecraft applications or in similar terrestrial structural-separation applications, devices of the proposed type would offer several advantages over explosive bolts: Unlike explosive bolts, the proposed devices would be reusable, could be tested before final use, and would not be subject to

  16. 冷弯薄壁型钢钢板-螺栓梁柱节点的力学性能分析%Mechanical properties investigation of cold-formed steel beam-column joints with bolt-plate

    Institute of Scientific and Technical Information of China (English)

    杨娜; 钟延营

    2011-01-01

    The ANSYS software is used to investigate the influential factors of the static behavior of gusset plate-bolted connection. The influential factors of the connections of three kinds of width of beam-column web were studied, including bolt pitch, the thickness of gusset plate, and the thickness of web and the width of flange and so on. It is found that the width of beam-column web the thickness of gusset plate, the thickness of web are highly effective factors for the static behavior,while the bolt pitch and the width of flange do not affect the initial stiffness and the ultimate bearing capacity of the joints. Finally, design proposals of three sections form connections are demonstrated, the dynamic performance of three kinds of recommended connections have been preliminarily studied in this paper.%为了观察不同梁、柱截面尺寸冷弯薄壁型钢钢板-螺栓节点静力性能的影响因素,采用AN-SYS软件对连接进行非线性有限元分析,研究3种梁柱腹板的节点螺栓间距、连接板厚度、腹板厚度和翼缘宽度等因素对其连接性能的影响.结果表明,梁柱腹板宽度、连接板厚度、梁柱腹板厚度是影响该连接节点静力性能的有效因素,而改变螺栓间距、梁柱翼缘宽度对节点的初始刚度和极限承载力的影响都不明显.给出了3种截面形式节点的设计建议,并对节点滞回性能进行了初步探讨,提出了滞回性能指标分析结论.

  17. Decision Fusion System for Bolted Joint Monitoring

    Directory of Open Access Journals (Sweden)

    Dong Liang

    2015-01-01

    Full Text Available Bolted joint is widely used in mechanical and architectural structures, such as machine tools, industrial robots, transport machines, power plants, aviation stiffened plate, bridges, and steel towers. The bolt loosening induced by flight load and environment factor can cause joint failure leading to a disastrous accident. Hence, structural health monitoring is critical for the bolted joint detection. In order to realize a real-time and convenient monitoring and satisfy the requirement of advanced maintenance of the structure, this paper proposes an intelligent bolted joint failure monitoring approach using a developed decision fusion system integrated with Lamb wave propagation based actuator-sensor monitoring method. Firstly, the basic knowledge of decision fusion and classifier selection techniques is briefly introduced. Then, a developed decision fusion system is presented. Finally, three fusion algorithms, which consist of majority voting, Bayesian belief, and multiagent method, are adopted for comparison in a real-world monitoring experiment for the large aviation aluminum plate. Based on the results shown in the experiment, a big potential in real-time application is presented that the method can accurately and rapidly identify the bolt loosening by analyzing the acquired strain signal using proposed decision fusion system.

  18. 30 CFR 75.204 - Roof bolting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Roof bolting. 75.204 Section 75.204 Mineral... or the equivalent may be used. (3) Bearing plates used with wood or metal materials shall be at least... against wood; or (ii) Have exceeded the maximum specified torque or tension by 50 percent. (6) The...

  19. Optimization of Bolt Stress

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The state of stress in bolts and nuts with ISO metric thread design is examined and optimized. The assumed failure mode is fatigue so the applied preload and the load amplitude together with the stress concentrations define the connection strength. Maximum stress in the bolt is found at, the fillet...... under the head, at the thread start or at the thread root. To minimize the stress concentration shape optimization is applied....

  20. Optimization of Bolt Stress

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The state of stress in bolts and nuts with ISO metric thread design is examined and optimized. The assumed failure mode is fatigue so the applied preload and the load amplitude together with the stress concentrations define the connection strength. Maximum stress in the bolt is found at, the fillet...... under the head, at the thread start or at the thread root. To minimize the stress concentration shape optimization is applied....

  1. Overall bolt stress optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The state of stress in bolts and nuts with International Organization for Standardization metric thread design is examined and optimized. The assumed failure mode is fatigue, so the applied preload and the load amplitude together with the stress concentrations define the connection strength....... Maximum stress in the bolt is found at the fillet under the head, at the thread start, or at the thread root. To minimize the stress concentration, shape optimization is applied. Nut shape optimization also has a positive effect on the maximum stress. The optimization results show that designing a nut......, which results in a more evenly distribution of load along the engaged thread, has a limited influence on the maximum stress due to the stress concentration at the first thread root. To further reduce the maximum stress, the transition from bolt shank to the thread must be optimized. Stress reduction...

  2. Bolting Multicenter Solutions

    CERN Document Server

    Bena, Iosif; Katmadas, Stefanos; Turton, David

    2016-01-01

    We introduce a solvable system of equations that describes non-extremal multicenter solutions to six-dimensional ungauged supergravity coupled to tensor multiplets. The system involves a set of functions on a three-dimensional base metric. We obtain a family of non-extremal axisymmetric solutions that generalize the known multicenter extremal solutions, using a particular base metric that introduces a bolt. We analyze the conditions for regularity, and in doing so we show that this family does not include solutions that contain an extremal black hole and a smooth bolt. We determine the constraints that are necessary to obtain smooth horizonless solutions involving a bolt and an arbitrary number of Gibbons-Hawking centers.

  3. Bolting multicenter solutions

    Science.gov (United States)

    Bena, Iosif; Bossard, Guillaume; Katmadas, Stefanos; Turton, David

    2017-01-01

    We introduce a solvable system of equations that describes non-extremal multicenter solutions to six-dimensional ungauged supergravity coupled to tensor multiplets. The system involves a set of functions on a three-dimensional base metric. We obtain a family of non-extremal axisymmetric solutions that generalize the known multicenter extremal solutions, using a particular base metric that introduces a bolt. We analyze the conditions for regularity, and in doing so we show that this family does not include solutions that contain an extremal black hole and a smooth bolt. We determine the constraints that are necessary to obtain smooth horizonless solutions involving a bolt and an arbitrary number of Gibbons-Hawking centers.

  4. Turbine casing bolts; a life assessment and bolt replacement strategy

    Energy Technology Data Exchange (ETDEWEB)

    Bulloch, J.H. [ESB, Power Generation, Dublin (Ireland)

    1998-12-31

    The present presentation describes a detailed study concerning the life assessment and replacement strategy of large turbine casing bolts in a 120 MW steam raising unit. After 122000 hours service, circa 1991/92, the Cr-Mo-V steel casing bolts, involving a total of 184 bolts, from two identical 120 MW units, termed Units 1 and 2, were examined to establish the extent of Reverse Temper Embrittlement, RTE, and creep damage suffered during service. The bolt replacement plans for the two units were as follows; Unit 1 bolts were completely replaced with new bolts while Unit 2 embrittled bolts were withdrawn from service and replaced with Non- Embrittled bolts from Unit 1; basically Unit 2 bolts were made up from a mixture of Unit 1 and 2 Non- Embrittled bolts which had been in service for 122000 hours. Remnant life assessments, concerning both embrittlement and creep damage aspects, were earned out on this series of easing bolts at service times 122000, 150000 and 200000 hours. These assessments involved the use of general embrittlement and creep damage laws which were empirically derived and concerned such parameters as microstructural grain size, bulk phosphorus content and accumulated service strain. (orig.) 7 refs.

  5. Bolt Thread Stress Optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2012-01-01

    Designs of threaded fasteners are controlled by different standards, and the number of different thread definitions is large. The most commonly used thread is probably the metric ISO thread, and this design is therefore used in this paper. Thread root design controls the stress concentration factor...... of threads and therefore indirectly the bolt fatigue life. The root shape is circular, and from shape optimization for minimum stress concentration it is well known that the circular shape is seldom optimal. An axisymmetric Finite Element (FE) formulation is used to analyze the bolted connection, and a study...... is performed to establish the need for contact modeling with regard to finding the correct stress concentration factor. Optimization is performed with a simple parameterization with two design variables. Stress reduction of up to 9% is found in the optimization process, and some similarities are found...

  6. Bolt Thread Stress Optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2012-01-01

    Designs of threaded fasteners are controlled by different standards, and the number of different thread definitions is large. The most commonly used thread is probably the metric ISO thread, and this design is therefore used in this paper. Thread root design controls the stress concentration factor...... of threads and therefore indirectly the bolt fatigue life. The root shape is circular, and from shape optimization for minimum stress concentration it is well known that the circular shape is seldom optimal. An axisymmetric Finite Element (FE) formulation is used to analyze the bolted connection, and a study...... is performed to establish the need for contact modeling with regard to finding the correct stress concentration factor. Optimization is performed with a simple parameterization with two design variables. Stress reduction of up to 9% is found in the optimization process, and some similarities are found...

  7. Prying Force Calculation and Design Method for T-shaped Tensile Connector with High Strength Bolt

    Institute of Scientific and Technical Information of China (English)

    Zhaoxin Hou; Guohong Huang; Chao Gong

    2015-01-01

    In order to establish the design method for T⁃shaped tensile connector with high strength bolt, the theoretical analysis is carried out. Firstly, it analyzes the performance of the connector and establishes prying force calculation model. Based on the model, prying force equation and function between bolt prying force and flange thickness is derived, and the min and max thickness requirement of flange plate under a certain tension load is then obtained. Finally, two simplified design methods of the connector are proposed, which are bolt pulling capacity method and flange plate bending capacity method.

  8. A Synthetic Phased Array Surface Acoustic Wave Sensor for Quantifying Bolt Tension

    Directory of Open Access Journals (Sweden)

    Rasim Guldiken

    2012-09-01

    Full Text Available In this paper, we report our findings on implementing a synthetic phased array surface acoustic wave sensor to quantify bolt tension. Maintaining proper bolt tension is important in many fields such as for ensuring safe operation of civil infrastructures. Significant advantages of this relatively simple methodology is its capability to assess bolt tension without any contact with the bolt, thus enabling measurement at inaccessible locations, multiple bolt measurement capability at a time, not requiring data collection during the installation and no calibration requirements. We performed detailed experiments on a custom-built flexible bench-top experimental setup consisting of 1018 steel plate of 12.7 mm (½ in thickness, a 6.4 mm (¼ in grade 8 bolt and a stainless steel washer with 19 mm (¾ in of external diameter. Our results indicate that this method is not only capable of clearly distinguishing properly bolted joints from loosened joints but also capable of quantifying how loose the bolt actually is. We also conducted detailed signal-to-noise (SNR analysis and showed that the SNR value for the entire bolt tension range was sufficient for image reconstruction.

  9. Post-Service Examination of PWR Baffle Bolts, Part I. Examination and Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, Keith J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sokolov, Mikhail A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-04-30

    In support of extended service and current operations of the US nuclear reactor plants, the Oak Ridge National Laboratory (ORNL), through the Department of Energy (DOE), Light Water Reactor Sustainability (LWRS) Program, is coordinating with Ginna Nuclear Power Plant, The Westinghouse Electric Company, LLC, and ATI Consulting, the selective procurement of baffle bolts that were withdrawn from service in 2011 and currently stored on site at Ginna. The goal of this program is to perform detailed microstructural and mechanical property characterization of baffle former bolts following in-service exposures. This report outlines the selection criteria of the bolts and the techniques to be used in this study. The bolts available are the original alloy 347 steel fasteners used in holding the baffle plates to the baffle former structures within the lower portion of the pressurized water reactor vessel. Of the eleven possible bolts made available for this work, none were identified to have specific damage. The bolts, however, did show varying levels of breakaway torque required in their removal. The bolts available for this study varied in peak fluence (highest dose within the head of the bolt) between 9.9 and 27.8x1021 n/cm2 (E>1MeV). As no evidence for crack initiation was determined for the available bolts from preliminary visual examination, two bolts with the higher fluence values were selected for further post-irradiation examination. The two bolts showed different breakaway torque levels necessary in their removal. The information from these bolts will be integral to the LWRS program initiatives in evaluating end of life microstructure and properties. Furthermore, valuable data will be obtained that can be incorporated into model predictions of long-term irradiation behavior and compared to results obtained in high flux experimental reactor conditions. The two bolts selected for the ORNL study will be shipped to Westinghouse with bolts of

  10. 钢板箍螺栓连接高强复合螺旋箍装配整体式柱抗震性能试验%SEISMIC BEHAVIOR RESEARCH OF STEEL PLATE HOOP-BOLT PREFABRICATED COLUMN CONFINED BY HIGH-STRENGTH COMPOSITE SPIRAL STIRRUPS

    Institute of Scientific and Technical Information of China (English)

    李进; 陈鹏; 魏威; 李青宁

    2014-01-01

    通过低周反复拟静力试验方法,研究钢板箍螺栓连接装配整体式柱的抗震性能。试验共设计4根长柱试件,观察各试件开裂、屈服、破坏全过程和破坏状态,得出各试件荷载-位移滞回曲线和骨架线,对比研究各试件承载力、延性和耗能能力,研究钢板箍螺栓连接方式的可行性。试验证明:钢板箍螺栓连接高强复合螺旋箍筋装配整体式柱和现浇整体柱具有相当的承载力和抗震能力,在连接可靠的情况下可以在工程中代替现浇柱。%In order to study the seismic behavior of steel plate hoop-bolt prefabricated column by high-strength composite spiral stirrups , the low cyclic loading tests were carried out .Four long column specimens were designed . Cracking, yield, destroyed process and destroyed state of specimens were observed in the tests , and the load-displacement hysteretic curves and skeleton curves of each specimen were also obtained .Comparative study on carrying capacity , ductility and energy dissipation capacity of each specimen was conducted , and analysis of the reliability of steel plate hoop-bolt connection was done .The test proves that steel plate hoop-bolt prefabricated column confined by high-strength composite spiral stirrups has about the same bearing capacity and seismic capacity as compared with cast-in-place column, and the prefabricated column can be used to replace the cast-in-place column in project in case of secure connections .

  11. Inhibition of spinach bolting by growth regulators

    Directory of Open Access Journals (Sweden)

    Jan Borkowski

    2015-06-01

    Full Text Available Spinach (Spinacia oleracea L. plants must be harvested during a short period of time because they bolt just after producing some edible leaves. Maleic hydrazide (MH and its commercial preparation "Antyrost" were found to inhibit bolting very strongly. The preparation Off-shoot-O showed very weak activity in suppressing bolting but diminished markedly the resistance of spinach plants to fungus diseases. Triiodobenzoic acid stimulated bolting, and the retardant succinic acid-2-2-dimethylhydrazide (SADH did not affect bolting. Application of MH to inhibit spinach bolting cannot be recommended in practice before investigating the residues of this compound in leaves.

  12. Smart washer—a piezoceramic-based transducer to monitor looseness of bolted connection

    Science.gov (United States)

    Huo, Linsheng; Chen, Dongdong; Kong, Qingzhao; Li, Hongnan; Song, Gangbing

    2017-02-01

    The safety of a bolted connection, as one of the most common ways of making two or more parts/components work together in engineering structures, is very important in order to ensure the health of the whole structure. However, bolt loosening or pre-load degradation may induce the failure of the bolt connection, threatening the normal operation of the system’s structure. As a result, it would be beneficial if the health condition of the bolt connection could be monitored in real time. In this paper, a ‘smart washer’, fabricated by embedding a piezoceramic patch into two pre-machined flat metal rings, was invented and then introduced as a transducer to detect the looseness of a bolted connection. A simple specimen, which consists of two steel plates connected by a nut, a bolt and two smart washers, was fabricated as the test object to study the performance of the ‘smart washers’ (SWs). For the specimen, a smart washer was used as an actuator to generate a stress wave, and the other one was used as a sensor to detect the propagated wave that traveled through the interface of the bolted connection. A time reversal method was employed to quantify the energy of the stress wave propagating between the two washers, and thus it was possible to build a relationship between the extent of any pre-loaded degradation of the bolt connection and the response signal of the stress wave traveling between the two washers. In addition, a normalized bolt looseness index was proposed for evaluating the looseness of a bolt connection based on wavelet energy analysis.

  13. Stress state and caving danger of the roof in bolt supporting roadway

    Institute of Scientific and Technical Information of China (English)

    LIU Shao-wei; XU Li-li

    2006-01-01

    The start point of this text is the bottleneck problem of bolt supporting coal entry that is security problem of bolt supporting roof,we divide one entry into some sections with different stress, simulate stress field of wall rock and rockbolt solidified at different sections used umbrella disperse soft UDEC(universal distinct element code), we educe that the stress level of wallrock and bolt solidified is higher in roof fall risk section, and roof rockbolt load can reflect this rule clearly, that offer an important guideline in monitoring entry roof fall risk.

  14. PLATE

    DEFF Research Database (Denmark)

    Kling, Joyce; Hjulmand, Lise-Lotte

    2008-01-01

    ’s level of English is sufficient for the increasing number of courses offered in English each semester. This paper addresses these concerns and describes a pilot project initiated in 2003 at CBS to gauge the overall English language proficiency of those teaching content courses in English. Through......Copenhagen Business School (CBS) finds itself needing to address the issue of English-medium instruction for its increasing number of foreign exchange and full degree students. With internationalisation as a main pillar of the institution’s agenda, there are concerns whether the teaching faculty...... the Project in Language Assessment for Teaching in English (PLATE) language professionals from CBS’s Language Center observe teachers and provide feedback using evaluation criteria from the Common European Framework for Reference (CEFR) supplemented by some additional criteria which take the LSP nature...

  15. PLATE

    DEFF Research Database (Denmark)

    Kling, Joyce; Hjulmand, Lise-Lotte

    2008-01-01

    Copenhagen Business School (CBS) finds itself needing to address the issue of English-medium instruction for its increasing number of foreign exchange and full degree students. With internationalisation as a main pillar of the institution’s agenda, there are concerns whether the teaching faculty......’s level of English is sufficient for the increasing number of courses offered in English each semester. This paper addresses these concerns and describes a pilot project initiated in 2003 at CBS to gauge the overall English language proficiency of those teaching content courses in English. Through...... the Project in Language Assessment for Teaching in English (PLATE) language professionals from CBS’s Language Center observe teachers and provide feedback using evaluation criteria from the Common European Framework for Reference (CEFR) supplemented by some additional criteria which take the LSP nature...

  16. Dividing Discipline

    DEFF Research Database (Denmark)

    Kristensen, Peter Marcus

    2012-01-01

    the periphery of the network—security studies and international political economy in particular—but communication is also divided along the lines of geography and policy/theory. The article concludes that divisions notwithstanding, IR communication remains centered around American, general, and theoretical IR...

  17. Study of the dynamic behavior of a bolted joint under heavy loadings

    Science.gov (United States)

    Daouk, Sami; Louf, François; Cluzel, Christophe; Dorival, Olivier; Champaney, Laurent; Audebert, Sylvie

    2017-03-01

    In structural dynamics, the quantification of the quality and reliability of numerical models remains a relevant issue. While the behavior of structures such as beams and plates is generally understood, a large number of industrial structures are bolted assemblies of many components with connections that are not well understood. The main reason for this lack of understanding is that the dynamical behavior of the whole assembly depends critically upon joint conditions, especially under heavy loadings. For the purpose of improving our understanding and the development of pertinent models, a dynamic test bed, based on a bolted structure, is designed and modal testing is performed. The configuration of the bolted joint and the level of the loading are the relevant parameters, related to joint conditions, that are considered in this study. The results of the experimental campaign show the variation of the dissipation in a bolted joint and its apparent stiffness as a function of joint conditions.

  18. A study of rock bolting failure modes

    Institute of Scientific and Technical Information of China (English)

    Cao Chen; Jan Nemcik; Ren Ting; Naj Aziz

    2013-01-01

    Rock bolting has advanced rapidly during the past 4 decades due to a better understanding of load transfer mechanisms and advances made in the bolt system technology.Bolts are used as permanent and temporary support systems in tunnelling and mining operations.A review of has indicated that three systems of reinforcement devices have evolved as part of rock bolt and ground anchor while the rock is not generally thought of as being a component of the reinforcement system.A classification of rock bolting reinforcement systems is presented,followed by the fundamental theory of the load transfer mechanism.The failure mode of two phases of rock bolting system is formularised.The failure modes of cable bolting are discussed using a bond strength model as well as an iterative method.Finally,the interfacial shear stress model for ribbed bar is introduced and a closed form solution is obtained using a tri-line stress strain relationship.

  19. The Influence on Modal Parameters of Thin Cylindrical Shell under Bolt Looseness Boundary

    Directory of Open Access Journals (Sweden)

    Hui Li

    2016-01-01

    Full Text Available The influence on modal parameters of thin cylindrical shell (TCS under bolt looseness boundary is investigated. Firstly, bolt looseness boundary of the shell is divided into two types, that is, different bolt looseness numbers and different bolt looseness levels, and natural frequencies and mode shapes are calculated by finite element method to roughly master vibration characteristics of TCS under these conditions. Then, the following measurements and identification techniques are used to get precise frequency, damping, and shape results; for example, noncontact laser Doppler vibrometer and vibration shaker with excitation level being precisely controlled are used in the test system; “preexperiment” is adopted to determine the required tightening torque and verify fixed constraint boundary; the small-segment FFT processing technique is employed to accurately measure nature frequency and laser rotating scanning technique is used to get shape results with high efficiency. Finally, based on the measured results obtained by the above techniques, the influence on modal parameters of TCS under two types of bolt looseness boundaries is analyzed and discussed. It can be found that bolt looseness boundary can significantly affect frequency and damping results which might be caused by changes of nonlinear stiffness and damping and in bolt looseness positions.

  20. Dividing Discipline

    DEFF Research Database (Denmark)

    Kristensen, Peter Marcus

    2012-01-01

    International Relations (IR) has cultivated an image as a discipline with strong divisions along paradigmatic, methodological, metatheoretical, geographical, and other lines. This article questions that image analyzing the latent structures of communication in IR. It uses citation data from more...... the periphery of the network—security studies and international political economy in particular—but communication is also divided along the lines of geography and policy/theory. The article concludes that divisions notwithstanding, IR communication remains centered around American, general, and theoretical IR...

  1. Removable Type Expansion Bolt Innovative Design

    Science.gov (United States)

    Wang, Feng-Lan; Zhang, Bo; Gao, Bo; Liu, Yan-Xin; Gao, Bo

    2016-05-01

    Expansion bolt is a kind of the most common things in our daily life. Currently, there are many kinds of expansion bolts in the market. However, they have some shortcomings that mainly contain underuse and unremovement but our innovation of design makes up for these shortcomings very well. Principle of working follows this: expansion tube is fixed outside of bolt, steel balls and expansion covers are fixed inside. Meanwhile, the steel balls have 120° with each other. When using it ,expansion cover is moved in the direction of its internal part. So the front part of expansion bolt cover is increasingly becoming big and steel halls is moved outside. Only in this way can it be fixed that steel balls make expansion tube expand. When removing them, expansion bolt is moved outside. So the front part of expansion bolt cover is gradually becoming small and steel balls moves inside, after expansion tube shrinks, we can detach them.

  2. A microprocessor based portable bolt tension monitor

    Science.gov (United States)

    Perey, D. F.

    1991-01-01

    A bolt tension monitor (BTM) which uses ultrasonics and a pulsed phase locked loop circuit to measure load-induced acoustic phase shifts which are independent of friction is described. The BTM makes it possible to measure the load in a bolt that was tightened at some time in the past. This capability to recertify a load after-the-fact will help to insure the integrity of a bolted joint.

  3. Failure Mode Analysis of Aluminium Alloy 2024-T3 in Double-Lap Bolted Joints with Single and Double Fasteners; A Numerical and Experimental Study

    Directory of Open Access Journals (Sweden)

    Khosro Fallahnezhad

    2015-06-01

    Full Text Available This paper aims to study the mechanical behaviour and failure mode of Al 2024-T3 in double-lap bolted joints. To accomplish this, the effect of geometric parameters was investigated in both configurations of single and double fasteners. Using ABAQUS/Standard, a three-dimensional finite element model was developed and verified against the experimental results of the joints loaded in tension. In general, double bolt joints were found to have greater load carrying capacities than single bolt joints (by 40%–49%. In single bolt joints, the plate width had insignificant effect on the behaviour of the joint under tensile loading; whereas, increasing the distance of the hole from the edge, considerably enhanced the strength of the joint. In double bolt joints, changing the edge distance had almost no effect on the behaviour of the joint. However, increasing the plate width from 25.4 to 30 mm increased the load carrying capacity by 28%. This study showed that in single bolt connections, with increasing the edge distance, the failure mode can favourably shift from shear-out to bearing. Also, double bolt joints with wider plates (increased width can beneficially shift the failure mode from net-tension to bearing. The geometric parameters were found to play an important role in controlling the failure mode so that catastrophic failure modes of net-tension and shear-out can be prevented in bolted joint.

  4. Research and application of U-shaped steel plate-concrete composite open-web sandwich slab structure with high strength bolts%U形钢板-混凝土高强螺栓连接组合空腹夹层板楼盖结构研究与应用

    Institute of Scientific and Technical Information of China (English)

    胡岚; 马克俭

    2012-01-01

    提出一种多层大跨度结构体系——U形钢板-混凝土高强螺栓连接组合空腹夹层板楼盖,该结构体系由U形钢板-混凝土组合下肋、钢筋混凝土上肋和上下肋间设置的钢筋混凝土剪力键形成的需考虑夹芯层剪切变形的空间楼盖。介绍了该楼盖结构体系的简化计算模型、弹性连续化理论分析方法和实用分析方法,通过仿真模型试验及实际工程应用,验证了弹性连续化理论分析方法与实用分析方法的正确性。研究结果表明:采用由上、下表层薄膜刚度和具有一定抗剪刚度的剪力键夹芯层组成的U形钢板-混凝土高强螺栓连接组合空腹夹层板楼盖简化计算模型进行弹性连续化理论分析,其分析结果与仿真模型试验结果基本相符,相对误差最大不超过5%;按等强和等刚度原则将U形钢板-混凝土组合空腹夹层板折算成钢筋混凝土实腹梁的实用分析方法,其计算结果与仿真模型试验结果基本相符,相对误差最大不超过4%。以黑龙江中医药大学文体中心B区57 m×39 m+57 m×36 m双跨多层(地下1层、地上3层)工程为算例,并与原位测试结果进行比较,说明U形钢板-混凝土高强螺栓连接组合空腹夹层板楼盖安全可靠,且具有较好的经济性。%A system of multilayer large span structure, the U-shaped steel plate and concrete composite open-web sandwich slab floor with high strength bolts was put forward. The structural system is composed of the U-shaped steel plate and concrete composite upper rib, the reinforced concrete bottom rib and the reinforced concrete shear keys between upper and bottom ribs, resulting in a sandwich layer of shear deformation of space floor. This paper comprehensively introduced the simplified calculation model of the structural system using the elastic continuum theory method and the practical analysis method, and verified the effectiveness of the model through the simulation

  5. The new structure of fibre glass reinforced plastics bolt

    Institute of Scientific and Technical Information of China (English)

    马念杰; 刘社育

    2003-01-01

    The develop actuality and direction of FRP(fibre glass reinforced plastics) bolt in the world are analyzed. The new type structure of FRP bolt was designed. Trial data indicate that, all kinds of capability target of this FRP bolt all achieve and exceed the country standard, substitute present metal bolt,wood bolt and bamboo bolt and other side bolt, it can gain magnitude technology and economy benefit. FRP bolt mechanization product line produce efficiency is high, its throughput a day are 750 base, this can meet demand of hit-small mining company.

  6. Device for measuring hole elongation in a bolted joint

    Science.gov (United States)

    Wichorek, Gregory R. (Inventor)

    1987-01-01

    A device to determine the operable failure mode of mechanically fastened lightweight composite joints by measuring the hole elongation of a bolted joint is disclosed. The double-lap joint test apparatus comprises a stud, a test specimen having a hole, two load transfer plates, and linear displacement measuring instruments. The test specimen is sandwiched between the two load transfer plates and clamped together with the stud. Spacer washers are placed between the test specimen and each load transfer plate to provide a known, controllable area for the determination of clamping forces around the hole of the specimen attributable to bolt torque. The spacer washers also provide a gap for the mounting of reference angles on each side of the test specimen. Under tensile loading, elongation of the hole of the test specimen causes the stud to move away from the reference angles. This displacement is measured by the voltage output of two linear displacement measuring instruments that are attached to the stud and remain in contact with the reference angles throughout the tensile loading. The present invention obviates previous problems in obtaining specimen deformation measurements by monitoring the reference angles to the test specimen and the linear displacement measuring instruments to the stud.

  7. Spacer lock of roof bolting

    Energy Technology Data Exchange (ETDEWEB)

    Shirokov, A.P.; Boronov, N.N.; Isachenko, V.M.; Kuntsevich, V.I.

    1980-04-05

    The object of the invention is a spacer joint of anchor bolting, which includes a wedge-shaped head and half-coupling, which are beveled on the inner side of the walls, and have ribs on the outer sides of the walls. It is characterized in that in order to reduce cost of the joint by reducing the amount of steel and manufacturing costs, the walls of the half-couplings hae identical thickness lengthwise, and the ribs are of varying height with corresponding projections on the inner side of the half-couplings.

  8. Thermal conductance measurements of bolted copper joints for SuperCDMS

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, R.; Tatkowski, Greg; Ruschman, M.; Golwala, S. R.; Kellaris, N.; Daal, M.; Hall, Jeter C.; Hoppe, Eric W.

    2015-09-01

    Joint thermal conductance testing has been undertaken for bolted copper to copper connections from 60 mK to 26 K. This testing was performed to validate an initial design basis for the SuperCDMS experiment, where a dilution refrigerator will be coupled to a cryostat via multiple bolted connections. Copper used during testing was either gold plated or passivated with citric acid to prevent surface oxidation. Results obtained are well fit by a power law regression of joint thermal conductance to temperature and match well with data collected during a literature review.

  9. Nonlinear Modeling and Identification of an Aluminum Honeycomb Panel with Multiple Bolts

    Directory of Open Access Journals (Sweden)

    Yongpeng Chu

    2016-01-01

    Full Text Available This paper focuses on the nonlinear dynamics modeling and parameter identification of an Aluminum Honeycomb Panel (AHP with multiple bolted joints. Finite element method using eight-node solid elements is exploited to model the panel and the bolted connection interface as a homogeneous, isotropic plate and as a thin layer of nonlinear elastic-plastic material, respectively. The material properties of a thin layer are defined by a bilinear elastic plastic model, which can describe the energy dissipation and softening phenomena in the bolted joints under nonlinear states. Experimental tests at low and high excitation levels are performed to reveal the dynamic characteristics of the bolted structure. In particular, the linear material parameters of the panel are identified via experimental tests at low excitation levels, whereas the nonlinear material parameters of the thin layer are updated by using the genetic algorithm to minimize the residual error between the measured and the simulation data at a high excitation level. It is demonstrated by comparing the frequency responses of the updated FEM and the experimental system that the thin layer of bilinear elastic-plastic material is very effective for modeling the nonlinear joint interface of the assembled structure with multiple bolts.

  10. Self drilling rock bolt technology - development of self drilling rock bolt

    Energy Technology Data Exchange (ETDEWEB)

    Peter Gray [Ground Support Services (Australia)

    2007-06-15

    A new Self Drilling Rock Bolt (SDRB) system has been developed which uses a pumpable resin system for full column resin encapsulation for immediate roof and rib support. A new drilling and injection system has also been developed to enable fast and efficient bolt installation. This new SDRB provides higher tensile strength than conventional solid bolts, and also provides a load transfer capacity that is almost double that of conventional bolts. This new SDRB uses low viscosity pumpable resin to ensure full encapsulation right down to the collar.

  11. Study on the material character steel big-end bolt

    Institute of Scientific and Technical Information of China (English)

    SHI Jian-jun; MA Nian-jie; ZHAN Ping; ZHANG Dian-li

    2008-01-01

    Based on the manufacturing method now used in our country,caused low bearing capacity in the bolt-end,which is a potential danger in the bolt supporting tunnel and a waste of money,and presented the new type strong steel big-end bolt can solve this problem.Analyzed the active state of the end of bolt by ANSYS,we can know that it is very disadvantage when bolt bore eccentric load.Contrasted with the different that common bolt and big-end bolt when they bore the same loading.The common bolt is bigger than the big-end bolt in stress value.Study on the processing technic of the new type of the strong steel big-end bolt,the new metal big-end bolt was produced by heat processing over big-end bolt and upset.From the microscopic examination on bolt metal,it is concluded that heat processing on the bolt-end refines the crystal grain of the metal material,which not only increase its extension but improve its property.Moreover the strength ability of the bolt material can be exerted completely.

  12. Study on the material character steel big-end bolt

    Institute of Scientific and Technical Information of China (English)

    SHI Jian-jun; MA Nian-jie; ZHAN Ping; ZHANG Dian-li

    2008-01-01

    Based on the manufacturing method now used in our country, caused low bear-ing capacity in the bolt-end, which is a potential danger in the bolt supporting tunnel and a waste of money, and presented the new type strong steel big-end bolt can solve this problem. Analyzed the active state of the end of bolt by ANSYS, we can know that it is very disadvantage when bolt bore eccentric load. Contrasted with the different that com-mon bolt and big-end bolt when they bore the same loading. The common bolt is bigger than the big-end bolt in stress value. Study on the processing technic of the new type of the strong steel big-end bolt, the new metal big-end bolt was produced by heat processing over big-end bolt and upset. From the microscopic examination on bolt metal, it is con-cluded that heat processing on the bolt-end refines the crystal grain of the metal material, which not only increase its extension but improve its property. Moreover the strength ability of the bolt material can be exerted completely.

  13. Bolt Cutter Blade's Imprint in Toolmarks Examination.

    Science.gov (United States)

    Volkov, Nikolai; Finkelstein, Nir; Novoselsky, Yehuda; Tsach, Tsadok

    2015-11-01

    Bolt cutters are known as cutting tools which are used for cutting hard objects and materials, such as padlocks and bars. Bolt cutter blades leave their imprint on the cut objects. When receiving a cut object from a crime scene, forensic toolmarks examiners can determine whether the suspected cutting tool was used in a specific crime or not based on class characteristic marks and individual marks that the bolt cutter blades leave on the cut object. The paper presents preliminary results of a study on ten bolt cutters and suggests a quick preliminary examination-the comparison between the blade thickness and the width of the imprint left by the tool on the cut object. Based on the comparison result, if there is not a match, the examiner can eliminate the feasibility of the use of the suspected cutting tool in a specific crime. This examination simplifies and accelerates the comparison procedure.

  14. Experimental study and stress analysis of rock bolt anchorage performance

    Directory of Open Access Journals (Sweden)

    Yu Chen

    2014-10-01

    Full Text Available A new method was developed to apply pull-and-shear loads to the bolt specimen in order to evaluate the anchorage performance of the rebar bolt and the D-Bolt. In the tests, five displacing angles (0°, 20°, 40°, 60°, and 90°, two joint gaps (0 mm and 30 mm, and three kinds of host rock materials (weak concrete, strong concrete, and concrete-granite were considered, and stress–strain measurements were conducted. Results show that the ultimate loads of both the D-Bolt and the rebar bolt remained constant with any displacing angles. The ultimate displacement of the D-Bolt changed from 140 mm at the 0° displacing angle (pure pull to approximately 70 mm at a displacing angle greater than 40°. The displacement capacity of the D-Bolt is approximately 3.5 times that of the rebar bolt under pure pull and 50% higher than that of the rebar bolt under pure shear. The compressive stress exists at 50 mm from the bolt head, and the maximum bending moment value rises with the increasing displacing angle. The rebar bolt mobilises greater applied load than the D-Bolt when subjected to the maximum bending. The yielding length (at 0° of the D-Bolt is longer than that of the rebar bolt. The displacement capacity of the bolts increased with the joint gap. The bolt subjected to joint gap effect yields more quickly with greater bending moment and smaller applied load. The displacement capacities of the D-Bolt and the rebar bolt are greater in the weak host rock than that in the hard host rock. In pure shear condition, the ultimate load of the bolts slightly decreases in the hard rock. The yielding speed in the hard rock is higher than that in the weak rock.

  15. Brain injuries caused by spherical bolts.

    Science.gov (United States)

    Roth, Jonathan; Mayo, Ami; Elran, Hanoch; Razon, Nissim; Kluger, Yoram

    2005-05-01

    Metallic particles contained in antihuman bombs increase the number of fatalities. The ballistics of these particles depends on the explosive that is used, the distance from the explosion, the shape of the particle projected, and the biomechanics of the injured tissue. The authors present their experience with penetrating spherical bolt injuries to the brain. The authors retrospectively reviewed clinical and radiological data obtained in eight patients with penetrating spherical bolt injuries to the cranium: four had Glasgow Coma Scale (GCS) scores less than 8 (three died, one from an unrelated injury) and four had a GCS score of 15 (all survived). Two of the latter patients suffered unique anatomical injuries attributed to the distinctive ballistics of spherical bolts: in one patient the bolt penetrated the cavernous sinus causing minimal cranial nerve injury, and in the other patient the bolt lodged in the fourth ventricle causing acute hydrocephalus without other neurological deficits. Penetrating spherical bolts to the brain may be lethal. Nevertheless, they have unique ballistics that cause highly delineated anatomical damage and minor neurological deficits.

  16. Strengths of composite-to-metal double-lap bolted joints

    Science.gov (United States)

    Sun, Hsien-Tang

    1998-12-01

    A three-dimensional analysis was proposed to study the through-the-thickness clamping effect on the bearing failure of double-lap bolted laminated composite joints. Experiments were first performed to characterize the material response due to bearing failure in composite bolted joints with and without lateral clamp-up supports. Composite plates made of T800H/3900-2 graphite/epoxy were selected in the tests, and various washer sizes and clamping forces were used in the study. The clamping force in the bolt was found to vary with the applied load, and may increase significantly due to a sudden through-the-thickness expansion of the laminate under the washers where bearing failure occurred. Experiments showed that the joint strength and response can be significantly affected by the bolt clamp-up, and the bolt bearing failure is a 3-D phenomenon. In order to facilitate the use of the proposed model with the ABAQUS code, an interface module 3DBOLT was developed. In order to reinforce the incompressibility condition in calculations for bearing-damaged material predicted by the model, the condition was imposed through a penalty method in the frame work of finite element analyses. The module provides a user-friendly input deck, generates automatically a joint mesh, and produces outputs and graphics for displaying the stresses, strains, and deformations of the joints and for simulating the failure progression in joints during loading. Extensive comparisons were made between the test data and model predictions. Overall, the model predicts both the failure load and response of bolted composite joints very well for various clamping forces and washer sizes. The model also predicted very well for joints failed in net-tension and shear-out modes. The predicted bolt clamp-up load as a function of the applied load agreed also very well with the data, which validates that the proposed incompressibility assumption for bearing-damaged material. Based on the model, a parametric study

  17. Analytical large deformation shear strength for bolted rough discontinuous rock

    Institute of Scientific and Technical Information of China (English)

    LIU Bo(刘波); TAO Long-guang(陶龙光); YUE Zhong-qi(岳中琦)

    2004-01-01

    Presented a new analytical model for studying the shear-tensile large deformation behavior near the vicinity of joint interface for bolted rough discontinuous rock, and presented the formulation estimating global shear strength for bolted joints under shearing-tensile loads. The analytical strength curves of bolts contribution on reinforced discontinuous rocks as the function of joint displacements or deformation angle of a bolt at rock joints was obtained. Based on Barton's equation on JRC roughness profiles, the theoretical shearing strength of bolted rough joints was also established. Test results on bolted granite and marble specimen confirm the validity of the analytical approach.

  18. More Nuts and Bolts of Michaelis-Menten Enzyme Kinetics

    Science.gov (United States)

    Lechner, Joseph H.

    2011-01-01

    Several additions to a classroom activity are proposed in which an "enzyme" (the student) converts "substrates" (nut-bolt assemblies) into "products" (separated nuts and bolts) by unscrewing them. (Contains 1 table.)

  19. More Nuts and Bolts of Michaelis-Menten Enzyme Kinetics

    Science.gov (United States)

    Lechner, Joseph H.

    2011-01-01

    Several additions to a classroom activity are proposed in which an "enzyme" (the student) converts "substrates" (nut-bolt assemblies) into "products" (separated nuts and bolts) by unscrewing them. (Contains 1 table.)

  20. Design of Bolted L-Flanged Connections

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2016-01-01

    on the tower and the tensile force in the bolt. In the literature and also in design standards different models are presented for this important non-linear response. The present work presents a simplified expression for the non-linear force response based on finite element calculations using contact analysis......In wind turbine towers the preferred design is circular tubes that are connected to each other by a bolted flange joint. The design is typically that of an L-flange resulting in an eccentrically loaded bolted connection. The eccentricity results in a non-linear relationship between external load....... Secondly, focus is on simple modifications of the flange design that considerably improves the strength of the connection....

  1. Retained crossbow bolt after penetrating facial trauma.

    Science.gov (United States)

    Shah, Manan U; Sridhara, Shankar K; Wolf, Jeffrey S; Ambro, Bryan T

    2016-01-01

    We present an unusual case of a retained crossbow bolt in the maxillofacial area of a 31-year-old man. While crossbow injuries are rare, this case is of interest because otolaryngologists are often faced with treating retained foreign objects after penetrating facial trauma. These cases are difficult to manage because of the complexity and variety of injuries that can occur during both the initial trauma and the removal. We focus on the management of the bolt's removal and provide a brief discussion of the relevant literature on crossbow injuries to the head and neck.

  2. Stiffness Analysis of Nail-Plate Joints Subjected to Short-Term Loads

    DEFF Research Database (Denmark)

    Nielsen, Jacob

    with beams connected in joints with glue or a mechanical fastener. The types of mechanical fasteners are: nails, staples, bolts, dowels, screws and nail-plates. Bolts and dowels are generally applied to joints in solid structures, and the other fasteners are used in all kinds of light structures. Especially...... types of plates. There are two main types of nail-plates: steel plates perforated with holes in which separate nails are used and steel plates perforated by a stamping machine, so the nails are made from the plate, see figur 1.2 on page 7. This type is sometimes called "punching metal plate...

  3. Stress wave propagation in supporting bolts: A test for bolt support quality

    Institute of Scientific and Technical Information of China (English)

    Wu Rui; Xu Jinhai; Li Chong; Zhou Baojing; Ma Qianqian; Wang Zhongliang

    2012-01-01

    A test method for the non-destructive determination of bolt length,anchoring length,and bolt body force is described.This addresses the problems of low accuracy,limited number of data,and untimely warning signs encountered with existing test methods.Numerical simulations of the bolt,resin,and rock system show that the length accuracy when using the velocity wave is lower than when using the acceleration wave.It is accepted practice to use the acceleration wave for length tests because of improved signal to noise ratios of the waveforms.Laboratory and in situ underground tests showed that the precision of the measurements meets field requirements.Using this method the anchor properties of each single bolt and,thus,the safety of the entire roadway support may be evaluated.

  4. Factors affecting penetrating captive bolt gun performance.

    Science.gov (United States)

    Gibson, Troy J; Mason, Charles W; Spence, Jade Y; Barker, Heather; Gregory, Neville G

    2015-01-01

    Captive bolt stunning is used for rendering livestock insensible at slaughter. The mechanical factors relating to performance of 6 penetrating captive bolt gun (CBG) models were examined. The Matador Super Sécurit 3000 and the .25 Cash Euro Stunner had the highest kinetic energy values (443 J and 412 J, respectively) of the CBGs tested. Ninety percent (27/30) of CBGs held at a government gun repository (United Kingdom) were found to have performed at a normal standard for the model, while 53% (10/19) of commercial contractor CBGs tested were found to underperform for the gun model. When the .22 Cash Special was fired 500 times at 4 shots per min, the gun reached a peak temperature of 88.8°C after 2.05 hr. Repeat firing during extended periods significantly reduced the performance of the CBG. When deciding on the appropriate CBG/cartridge combination, the kinetic energy delivered to the head of the nonhuman animal, bolt penetration depth, and species/animal type must be considered. It is recommended that CBGs are routinely checked for wear to the bolt and barrel if they are repeatedly fired in a session.

  5. Strength of Bolted Joints in Laminated Composites

    Science.gov (United States)

    1984-03-01

    Analysis of Single and Two-Hole Bolted Joints in Fibre Reinforced Plastic ," J. of Composite Materials, Vol. 16, 1982, pp.481-491. 11. N,J. Pagano, R.B...Effect of Stacking Sequence on the Pin-Bearing Strength in Glass Fibre Reinforced Plastic ,’ J. of Composite Materials, Vol. 11, 1977, pp. 139-145. 13., J.M

  6. Inedible Nuts and Non-Lightning Bolts

    Science.gov (United States)

    Rynone, William

    2010-01-01

    In this article, the author provides detailed information on a wide variety of commonly used screws, bolts, and other fasteners. The information has been gathered in his engineering career and outside interests (maintenance on his car and airplane, and woodworking). The topic should be of interest to students and educators in many technical…

  7. Inedible Nuts and Non-Lightning Bolts

    Science.gov (United States)

    Rynone, William

    2010-01-01

    In this article, the author provides detailed information on a wide variety of commonly used screws, bolts, and other fasteners. The information has been gathered in his engineering career and outside interests (maintenance on his car and airplane, and woodworking). The topic should be of interest to students and educators in many technical…

  8. A Review of Rock Bolt Monitoring Using Smart Sensors.

    Science.gov (United States)

    Song, Gangbing; Li, Weijie; Wang, Bo; Ho, Siu Chun Michael

    2017-04-05

    Rock bolts have been widely used as rock reinforcing members in underground coal mine roadways and tunnels. Failures of rock bolts occur as a result of overloading, corrosion, seismic burst and bad grouting, leading to catastrophic economic and personnel losses. Monitoring the health condition of the rock bolts plays an important role in ensuring the safe operation of underground mines. This work presents a brief introduction on the types of rock bolts followed by a comprehensive review of rock bolt monitoring using smart sensors. Smart sensors that are used to assess rock bolt integrity are reviewed to provide a firm perception of the application of smart sensors for enhanced performance and reliability of rock bolts. The most widely used smart sensors for rock bolt monitoring are the piezoelectric sensors and the fiber optic sensors. The methodologies and principles of these smart sensors are reviewed from the point of view of rock bolt integrity monitoring. The applications of smart sensors in monitoring the critical status of rock bolts, such as the axial force, corrosion occurrence, grout quality and resin delamination, are highlighted. In addition, several prototypes or commercially available smart rock bolt devices are also introduced.

  9. Bolting Cabin Assistance System Using a Sensor Network

    Directory of Open Access Journals (Sweden)

    Yung-Hak Mo

    2012-10-01

    Full Text Available The bolting cabin assistance system prevents operators from facing dangerous situations. This system consists of a bolting robot control system and a top view supervisory system. In order to control the bolting robot, circular Hough transforms and fuzzy reasoning are used. First, the circular Hough transform roughly estimates the location of the bolt hole. After that, errors of estimation are compensated for using fuzzy reasoning. In order to track a bolt hole, a region of interest (ROI is used. By setting the region in which to search for a bolt hole, the algorithm tracks the location of the bolt hole. In order to choose an ROI, a template‐based matching algorithm is used. In order to make the top view supervisory system, four cameras are installed at the left, right, front and back of the robot. The four individual images from the various cameras are combined to make the top view image after correcting for distortion.

  10. Parameters determination and bolting control of gateway floor

    Institute of Scientific and Technical Information of China (English)

    GOU Pan-feng; XlN Ya-jun

    2011-01-01

    Gateway floor heave control is the key to guarantee mine safe and efficient production.Through analysis of floor instability characteristics and bolting control,gateway floor strata show second level stress under abutment pressure,which causes plastic flow failure in floor strata; gateway floor instability shows mainly shear-break slippage of “triangle sliding body”.Mechanics of floor bolting is mainly a function of connection and combination.Main area of bolting control lies in two gateway floor angles.The paper analyzes mechanics principle of gateway floor instability,constructs stability mechanics model of gateway floor bolting,obtains gateway floor stability criterion of different bolting angles and optimum formula of bolting parameters,carries out the engineering example,and guides better field application.It provides theoretical base for bolting gateway floor instability control.

  11. Mathematical Model of Load Pass and Prediction of Fatigue Life on Bolt Threads with Reduced Lead

    Science.gov (United States)

    Asayama, Yukiteru

    A mathematical model is proposed in order to elucidate the mechanism that the fatigue strength of external threads increases by reducing the lead on a thread system such as a bolt and nut. The model is constructed from the concept that a local strain proportional to the reducing degree of the lead, although the local strain is at first produced in the bolt thread farthest from the bearing surface of the nut, is induced in each thread root with an increase of applied load. The fatigue life predicted from the mathematical model shows good agreement with the experimental fatigue life of cadmium-plated external threads with the reduced lead on the material having strength as high as 1270MPa. The model can provide useful suggestions for the design of fasteners for aerospace, which are required to satisfy severe requirements of fatigue strengths and dimensions.

  12. The design and testing of subscale smart aircraft wing bolts

    Science.gov (United States)

    Vugampore, J. M. V.; Bemont, C.

    2012-07-01

    Presently costly periodic inspection is vital in guaranteeing the structural integrity of aircraft. This investigation assesses the potential for significantly reducing aircraft maintenance costs without modification of aircraft structures by implementing smart wing bolts, manufactured from TRIP steel, which can be monitored for damage in situ. TRIP steels undergo a transformation from paramagnetic austenite to ferromagnetic martensite during deformation. Subscale smart aircraft wing bolts were manufactured from hot rolled TRIP steel. These wing bolts were used to demonstrate that washers incorporating embedded inductance coils can be utilized to measure the martensitic transformation occurring in the TRIP steel during bolt deformation. Early in situ warning of a critical bolt stress level was thereby facilitated, potentially reducing the costly requirement for periodic wing bolt removal and inspection. The hot rolled TRIP steels that were utilized in these subscale bolts do not however exhibit the mechanical properties required of wing bolt material. Thus warm rolled TRIP steel alloys were also investigated. The mechanical properties of the best warm rolled TRIP steel alloy tested almost matched those of AISI 4340. The warm rolled alloys were also shown to exhibit transformation before yield, allowing for earlier warning when overload occurs. Further work will be required relating to fatigue crack detection, environmental temperature fluctuation and more thorough material characterization. However, present results show that in situ early detection of wing bolt overload is feasible via the use of high alloy warm rolled TRIP steel wing bolts in combination with inductive sensor embedded washers.

  13. Infrastructure anchor bolt inspection program with NDE applications

    Science.gov (United States)

    Fish, Philip E.

    1996-11-01

    In 1990, Wisconsin Department of Transportation found a high mast light pole with two of six anchor bolts failed. This failure along with published reports from Michigan DOT about anchor bolt failures on cantilever sign structures, raised concern about the quality and condition of anchor bolts on the Wisconsin DOT system. Wisconsin Department of Transportation implemented an Anchor Bolt Inspection Program in 1990 for cantilever sign structures, high mast light towers, interstate light towers, and signal masts. The program requires an experienced inspection team and a practical inspection approach. Inspection preparation includes review of all background information such as design plans, design computations, construction plans, shop plans, and maintenance history. An inspection plan is developed. Special emphasis is placed on determining material type, cut or rolled threads, and type of coating for anchor bolts. Inspection emphasis are on "hands on" and Nondestructive evaluation. Special emphasis is placed on visual conditions of anchor bolts (cut or rolled threads, straightness, corrosion, nut tension etc.) along with ultrasonic inspection. This program places a strong emphasis on Non Destructive Testing (NDT), especially ultrasonic. Procedures and inspection calibrations are developed from similar anchor bolt geometry and material type. Cut notches are placed in the anchor bolts at locations of possible failure. NDT inspection calibrations are performed from these bolts. Report documentation includes all design plans, pictorial documentation of structural deficiencies, sketches, nondestructive evaluation reports, conclusions, and recommendations. This program has been successful in locating failed anchor bolts and critical cracks before failure of an entire structure.

  14. HYSTERETIC BEHAVIOR STUDY ON CONNECTION OF PEC COLUMNS-STEEL BEAM WITH END PLATES AND PRETENSION HIGH-STRENGTH PENETRATING BOLTS%薄钢板PEC柱-钢梁端板对拉螺栓连接滞回性能试验研究

    Institute of Scientific and Technical Information of China (English)

    马吉; 方有珍; 陆承铎; 韩昌标; 孙国华

    2013-01-01

    The PEC column fabricated with thin-walled built-up section-steel beam connections with reduced cross sections,end plates and pretension high-strength penetrating bolts,the column layout and reduced cross-section location were taken as the design parameters,and 3 specimens were designed and fabricated by 1 ∶ 0.625 scale,which represented the middle joints.The test of the specimens was conducted under lateral cyclic loading in the column strong or weak axis,the test process was observed and the hysteretic curves were obtained.Based on the test results,the joints' global responses were analyzed,including the hysteretic behaviors,degradation of strength and flexural stiffness,energy-dissipation capacity,the ductility property and the failure mode.The conclusion showed that the specimens exhibited various degrees of self-centering functions,sound ductility and energy-dissipation capacity; the failure mode formed primary induced by yielding in the reduced cross-section or near the welding position of a steel beam.The study provides an experimental basis for amending the specification and engineering practice adopting the structure comprised of PEC columns-steel beams.%薄钢板组合截面PEC柱-钢梁连接中节点,采取工字梁端截面削弱、端板与预拉对穿高强螺栓的连接方式,考虑组合柱布置与梁削弱截面位置变化作为设计参数,对3个PEC柱-削弱梁、短端板对穿螺栓连接中节点1∶0.625缩尺模型进行低周反复荷载下的滞回性能试验.观察各个试件试验中的破坏过程,通过实测数据分析,得到了该类框架连接节点的滞回性能、强度与转动刚度退化、延性与耗能能力和破坏模式.结果表明:由于预拉对穿螺栓的设置,所有试件均表现出不同程度的自复位效果和良好的转动与耗能能力;节点的破坏模式为钢梁削弱截面或连接部位附近截面屈服.研究进一步丰富了PEC柱-钢梁连接的研究成果,为PEC柱-钢梁组合

  15. Finite element analysis of bolted flange connections

    Science.gov (United States)

    Hwang, D. Y.; Stallings, J. M.

    1994-06-01

    A 2-D axisymmetric finite element model and a 3-D solid finite element model of a high pressure bolted flange joint were generated to investigate the stress behaviors. This investigation includes comparisons for axisymmetric loading of both the 2-D and 3-D models, the effects of non-axisymmetric bolt pretensions in the 3-D models, and the differences between 2-D and 3-D models subjected to non-axisymmetric loading. Comparisons indicated differences in von Mises stress up to 12% at various points due to the non-axisymmetric bolt pretensions. Applied bending moments were converted to equivalent axial forces for use in the 2-D model. It was found that the largest von Mises stresses in 3-D model did not occur on the side of the connection where the bending stresses and applied axial stresses were additive. Hence, in the 2-D model where the equivalent axial force (for bending moment) and applied axial forces were added, the 2-D model under estimated the maximum von Mises stress obtained from the 3-D model by 30%.

  16. Investigation of Fastening Performance of Subminiature Serrated Bolt

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Myung Guen; Jeong, Jin Hwan; Jang, Yeon Hui; Kim, Hee Cheol; Kim, Jong-Bong [Seoul Nat’l Univ. of Science & Tech, Seoul (Korea, Republic of)

    2017-04-15

    As the size of electric products such as mobile phones and smart watches decrease, the bolts used to assemble these products should also be miniaturized. A miniature-sized bolt has to provide sufficient joining torque and anti-releasing torque to keep the components together. We studied a serrated bolt as a candidate for a miniature-sized fastener to increase the anti-releasing torque. In a serrated bolt, a serrated shape is formed on the bottom surface of the bolt head to create an obstacle to releasing. In this study, finite element analyses for the joining and releasing of bolts were carried out, and the anti-releasing performance was predicted. Based on the results of analyses using various numbers of serrations and fastening depths, the effects of the number of serrations and fastening depth on the anti-releasing performance were investigated.

  17. Characteristic Evaluation on Bolt Stress by Ultrasonic Nondestructive Methods

    Directory of Open Access Journals (Sweden)

    Qinxue Pan

    2015-01-01

    Full Text Available Based on the acoustoelasticity theory, a certain relationship exists between ultrasonic velocity and stress. By combining shear and longitudinal waves, this paper provides a nondestructive method of evaluating axial stress in a tightened bolt. For measuring the bolt axial stress in different situations, such as under low or high loads, this paper provides guidelines for calculating the stress for a given load factor. Experimental and calculated results were compared for three bolt test samples: an austenitic stainless steel bolt (A2-70 and low-carbon steel 4.8 and 8.8 bolts. On average, the experimental results were in good agreement with those obtained through calculations, thus providing a nondestructive method for bolt stress measurements.

  18. Continental Divide Trail

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This shapefile was created to show the proximity of the Continental Divide to the Continental Divide National Scenic Trail in New Mexico. This work was done as part...

  19. Battery with a terminal bolt. Akkumulator mit einem Schraubpol

    Energy Technology Data Exchange (ETDEWEB)

    Georges, K.H.

    1987-01-02

    A battery with a bolt terminal is claimed. A bolt of a conductive material is screwed into a thread, and the head of the screw is covered with an insulating layer. To enable direct terminal voltage measurement while maintaining the protection against corrosive liquid electrolyte, there is a recess in the bolt head which is filled with an electrically conductive, acid-resistant material (lead).

  20. Strength of Glued-in Bolts after Full Scale Loading

    DEFF Research Database (Denmark)

    Pedersen, Martin Bo Uhre; Clorius, Christian Odin; Damkilde, Lars;

    1999-01-01

    In 1993 after 9 years of use one of the blades of a windmill with wooden blades was struck by lightning. After demounting the damaged blade was handed over to the Technical University of Denmark for the investigation of potential fatigue damage. The paper presents an experimental determination...... of the residual strength of the glued-in bolts that served as the blade to rotor hub connection in the windmill. The load history of the bolts, the test method, the observed fracture modes and the force displacement curves are presented along with the recorded residual strength of the bolts. The bolts...

  1. Experimental Study on Shear Performance of Bolt in Roadway Supporting

    Directory of Open Access Journals (Sweden)

    D.J. Li

    2014-09-01

    Full Text Available The corner bolt is proved to be effective in the control of floor deformation of roadway, and the relevant studies on bolting mechanisms are of great significance in improving roadway stability. In this paper, two types of shear tests on six forms of bolts are performed by using self-designed shear test device, the electro-hydraulic servo triaxial testing system. The shear characteristics of different types of bolts are obtained. The results show that different bolt rods or different internal filling conditions result in large differences in shear resistance and different deformation adaptability. We find that the filling materials added can improve the shear performance of bolt significantly, and the bolt with steel not only can improve the strength of bolt body, but also has the bimodal characteristic that makes the bolt have the secondary bearing capacity and withstand larger deformation range during the process of shear, and shows a better support performance. Hoping to provide the experiment basis for support design and field application in the future.

  2. Research on the mechanical property test of a new high-strength metal bolt

    Institute of Scientific and Technical Information of China (English)

    SHI Jian-jun; MA Nian-jie

    2011-01-01

    In order to study how to improve the overall performance of the operational metal bolt,based on the production process of an ordinary metal bolt used in understructure engineering,this paper focused on the existing problems of ordinary metal bolts identified by some survey and analysis.The results show that the structure of operational metal bolts is so unreasonable that the bolt tail is easily fractured by low load capacity.Furthermore,a new type of strong big-end metal bolt and its heat treatment and roughing processing technology were introduced.Through bolt tensile and metallographic tests,the property of the new big-end bolt was analyzed.The new findings indicate that after a special processing,the overall strength and plasticity of the bolt is greatly improved,and the grain of the bolt tail structure is refined,which would help build up favorable working conditions for bolt tails.

  3. International Divider Walls

    NARCIS (Netherlands)

    Kruis, A.; Sneller, A.C.W.(L.)

    2013-01-01

    The subject of this teaching case is the Enterprise Resource Planning (ERP) system implementation at International Divider Walls, the world market leader in design, production, and sales of divider walls. The implementation in one of the divisions of this multinational company had been successful, a

  4. International Divider Walls

    NARCIS (Netherlands)

    Kruis, A.; Sneller, A.C.W.(L.)

    2013-01-01

    The subject of this teaching case is the Enterprise Resource Planning (ERP) system implementation at International Divider Walls, the world market leader in design, production, and sales of divider walls. The implementation in one of the divisions of this multinational company had been successful,

  5. A study of high-strength bolts after dephosphoring

    Directory of Open Access Journals (Sweden)

    Shao-Yi Hsia

    2016-03-01

    Full Text Available A wide variety of fasteners are produced, including those for the automobile industry, household electrical appliances industry, architectural engineering, and even the aviation industry. The effects of the high-tensile bolt dephosphoring process on the entire fastener manufacturing process and its organizational characteristics and mechanical properties are analyzed and discussed in this study. Our experimental results reveal that the bolt dephosphoring process must be completed before heat treatment, which can be confirmed with a dephosphoring reagent or metallographic observation. Once bolt heat treatment is completed, bolts without dephosphoring appear to be coated with δ ferrite (delta ferrite composed of a phosphate coating and a phosphatizing coating, which are not easily removed. Heat treatment with phosphorus results in grain boundary segregation, causing embrittlement and a reduction in lattice bonding forces and resulting in a high risk of fracturing when bolts are used in high-temperature environments or undergo multiaxial stresses.

  6. The effects of bolted joints on dynamic response of structures

    Science.gov (United States)

    Zaman, I.; Khalid, A.; Manshoor, B.; Araby, S.; Ghazali, M. I.

    2013-12-01

    Joint is an universal fastening technology for structural members; in particular bolted joints are extensively used in mechanical structures due to their simple maintenance and low cost. However, the components of bolted joints are imperative because failure could be catastrophic and endanger lives. Hence, in this study, the effects of bolted joints on vibrating structures are investigated by determining the structural dynamic properties, such as mode shapes, damping ratios and natural frequencies, and these are compared with the monolithic structures (welding). Two approaches of experimental rigs are developed: a beam and a frame where both are subjected to dynamic loading. The analysis reveals the importance of bolted joints in increasing the damping properties and minimizing the vibration magnitude of structures, this indicates the significant influence of bolted joints on the dynamic behaviour of assembled structures. The outcome of this study provides a good model for predicting the experimental variable response in different types of structural joints.

  7. Effect of parameters on local stress field in single-lap bolted joints with the interference fit

    Directory of Open Access Journals (Sweden)

    Jiefeng Jiang

    2016-05-01

    Full Text Available From the interference fit bolt installation to tensile loading stage in single-lap joint with a hi-lock bolt, the stress and strain fields were studied experimentally and numerically. A three-dimensional finite element model was generated to simulate the experimental setup, which was validated using the experimental data. The fatigue behavior of the bolted joint is influenced by the local stress fields on the faying surface near the holes in single-lap joints. Therefore, with the aim to improve design awareness, the effects of the parameters on the local stress fields were investigated by means of finite element simulation. With an increase in the interference fit size, the occurred position of the maximum stress values on the upper plate faying surface moves away from the hole edge gradually. As the clamping force or friction coefficient increases, the position of larger stress area is changed to the side of bearing load from the transverse direction. The lap geometry of the bolted joint as well as the amplitude of tensile load has apparent impact on the maximum stress value.

  8. The supersymmetric NUTs and bolts of holography

    Energy Technology Data Exchange (ETDEWEB)

    Martelli, Dario; Passias, Achilleas [Department of Mathematics, King' s College London, The Strand, London WC2R 2LS (United Kingdom); Sparks, James [Mathematical Institute, University of Oxford, 24-29 St Giles' , Oxford OX1 3LB (United Kingdom)

    2013-11-21

    We show that a given conformal boundary can have a rich and intricate space of supersymmetric supergravity solutions filling it, focusing on the case where this conformal boundary is a biaxially squashed Lens space. Generically we find that the biaxially squashed Lens space S{sup 3}/Z{sub p} admits Taub-NUT-AdS fillings, with topology R{sup 4}/Z{sub p}, as well as smooth Taub-Bolt-AdS fillings with non-trivial topology. We show that the Taub-NUT-AdS solutions always lift to solutions of M-theory, and correspondingly that the gravitational free energy then agrees with the large N limit of the dual field theory free energy, obtained from the localized partition function of a class of N=2 Chern–Simons-matter theories. However, the solutions of Taub-Bolt-AdS type only lift to M-theory for appropriate classes of internal manifold, meaning that these solutions exist only for corresponding classes of three-dimensional N=2 field theories.

  9. Evaluation of bolted connections in wood-plastic composites

    Science.gov (United States)

    Arnandha, Yudhi; Satyarno, Iman; Awaludin, Ali; Irawati, Inggar Septia; Ihsan, Muhamad; Wijanarko, Felyx Biondy; William, Mahdinur, Fardhani, Arfiati

    2017-03-01

    Wood-plastic composite (WPC) is a relatively new material that consists of sawdust and plastic polymer using the extrusion process. Due to its attributes such as low water content, low maintenance, UV durability and being fungi and termite resistant. Nowadays, WPC has already been produced in Indonesia using sawdust from local wood such as Albizia (Paraserianthes falcataria) and Teak (Tectona grandis). Moreover preliminary studies about the physical and mechanical WPC board from Albizia sawdust and HDPE plastic have been carried out. Based on these studies, WPC has a high shear strength around 25-30 MPa higher than its original wood shear strength. This paper was a part of the research in evaluating WPC as potential sheathing in a shear wall system. Since still little is known about connection behavior in WPC using Indonesian local wood, this study evaluated the connection for both of these two types of wood-plastic composite. WPC board from Albizia sawdust will be projected as shear wall sheathing and WPC stud from Teak sawdust projected to be shear wall frame. For this study, the embedding strength for both WPC was determined according to ASTM D 5764 standard, using two types of bolts (stainless bolt and standard bolt) with several diameters as variation (6 mm, 8 mm, 10 and 12 mm). Hence, dowel-bearing test under fastened condition conducted accordance to ASTM D5652, hereby the yield strength then compared with the prediction yield strength from European Yield Model (EYM). According to both single and double shear connection, it can be concluded that yield strength from the EYM method tended to under-predict the 5% diameter offset yield than the actual yield strength from the test. The yield strength itself increase with the increase of bolt diameter. For single shear connection, the highest yield strength was 12 mm standard bolt around 9732 N, slightly higher than stainless bolt around 9393 N. Whereby for double shear connection, the highest yield strength was

  10. Bridging the Digital Divide

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    2002-01-01

    The article concerns the digital divide, meaning the social inequity in the access and the opportunities for gaining competencies with ICT (information and communication technologies). Problematic issues are highlighted in relation to experiences during visits to several Computer Clubhouses...

  11. The Open Access Divide

    National Research Council Canada - National Science Library

    Jingfeng Xia

    2013-01-01

      This paper is an attempt to review various aspects of the open access divide regarding the difference between those academics who support free sharing of data and scholarly output and those academics who do...

  12. Factors Influencing the Quality of Encapsulation in Rock Bolting

    Science.gov (United States)

    Aziz, Naj; Craig, Peter; Mirzaghorbanali, Ali; Nemcik, Jan

    2016-08-01

    Bolt installation quality is influenced by various factors, some are well known and others are less recognised. A programme of field and laboratory studies was undertaken to examine various factors of relevance to the load transfer mechanism between the bolt, resin and rock to ensure test methods truly represent field performance. Short encapsulation tests were undertaken as part of the Australian Coal Association Research Program (ACARP) funded project (C21011) with the ultimate aim of developing standard test methods for assessing bolt encapsulation with chemical resin anchor installations. The field study consisted of a series of Short Encapsulation Pull Tests (SEPT) carried out in three mines with different geological conditions to determine the most representative and practical method of SEPT. Additional field work included installation of bolts into threaded steel tubes for subsequent removal and laboratory evaluation. A series of pull tests was carried out by installing bolts in overhead rig mounted sandstone block, cast in concrete with controlled encapsulation length. Factors of importance considered included; borehole diameter, resin annulus thickness, installation time (including bolt spin to the back and "spin at back"), the effect of gloving and hole over drill. It was found that the borehole diameter had a detrimental effect on the encapsulation bonding strength. Bolt installation time of approximately 10 s constituted an acceptable time for effective bolt installation and within the resin manufacturers recommended time of 14 s. Maintaining constant length of encapsulation was paramount for obtaining consistency and repeatability of the test results. Finally, a numerical simulation study was carried out to assess the capabilities of FLAC 2D software in simulating the pull testing of rock bolts.

  13. Epigenomics and bolting tolerance in sugar beet genotypes

    Science.gov (United States)

    Hébrard, Claire; Peterson, Daniel G.; Willems, Glenda; Delaunay, Alain; Jesson, Béline; Lefèbvre, Marc; Barnes, Steve; Maury, Stéphane

    2016-01-01

    In sugar beet (Beta vulgaris altissima), bolting tolerance is an essential agronomic trait reflecting the bolting response of genotypes after vernalization. Genes involved in induction of sugar beet bolting have now been identified, and evidence suggests that epigenetic factors are involved in their control. Indeed, the time course and amplitude of DNA methylation variations in the shoot apical meristem have been shown to be critical in inducing sugar beet bolting, and a few functional targets of DNA methylation during vernalization have been identified. However, molecular mechanisms controlling bolting tolerance levels among genotypes are still poorly understood. Here, gene expression and DNA methylation profiles were compared in shoot apical meristems of three bolting-resistant and three bolting-sensitive genotypes after vernalization. Using Cot fractionation followed by 454 sequencing of the isolated low-copy DNA, 6231 contigs were obtained that were used along with public sugar beet DNA sequences to design custom Agilent microarrays for expression (56k) and methylation (244k) analyses. A total of 169 differentially expressed genes and 111 differentially methylated regions were identified between resistant and sensitive vernalized genotypes. Fourteen sequences were both differentially expressed and differentially methylated, with a negative correlation between their methylation and expression levels. Genes involved in cold perception, phytohormone signalling, and flowering induction were over-represented and collectively represent an integrative gene network from environmental perception to bolting induction. Altogether, the data suggest that the genotype-dependent control of DNA methylation and expression of an integrative gene network participate in bolting tolerance in sugar beet, opening up perspectives for crop improvement. PMID:26463996

  14. The Open Access Divide

    Directory of Open Access Journals (Sweden)

    Jingfeng Xia

    2013-10-01

    Full Text Available This paper is an attempt to review various aspects of the open access divide regarding the difference between those academics who support free sharing of data and scholarly output and those academics who do not. It provides a structured description by adopting the Ws doctrines emphasizing such questions as who, what, when, where and why for information-gathering. Using measurable variables to define a common expression of the open access divide, this study collects aggregated data from existing open access as well as non-open access publications including journal articles and extensive reports. The definition of the open access divide is integrated into the discussion of scholarship on a larger scale.

  15. A dividing issue

    DEFF Research Database (Denmark)

    Gamborg, Christian; Jensen, Frank Søndergaard; Sandøe, Peter

    2016-01-01

    . While there was broad agreement across all three groups that recreational hunting of naturally occurring “surplus” wildlife is acceptable, the release of farm-reared game birds for shooting was a dividing issue, both within the groups and between them. The majority of participants (51%) in the survey...

  16. Study on Rock Bolt Reinforcement for a Gravity Dam Foundation

    Science.gov (United States)

    Chen, S. H.; Yang, Z. M.; Wang, W. M.; Shahrour, I.

    2012-01-01

    In this article, the rock bolt reinforcement mechanism is discussed, and the gravity method as well as the finite element method for the bolted rock is presented. These methods are applied to study the gravity dam foundation of the Xiaoxi Hydropower Project, which is influenced by the presence of a large fault with a cracked zone over 180 m wide. Rock bolt reinforcement was used to improve the stability of the dam foundation, and the reinforcement parameters were determined from a semi-empirical equation controlled by in situ test. The stability analysis was conducted using the above methods, and the improvement in terms of deformation and stress as well as stability of the dam foundation due to the reinforcement is assessed. Rock bolt reinforcement was completed successfully, and the dam started normal operations in January 2008.

  17. Mechanics of Re-Torquing in Bolted Flange Connections

    Science.gov (United States)

    Gordon, Ali P.; Drilling Brian; Weichman, Kyle; Kammerer, Catherine; Baldwin, Frank

    2010-01-01

    It has been widely accepted that the phenomenon of time-dependent loosening of flange connections is a strong consequence of the viscous nature of the compression seal material. Characterizing the coupled interaction between gasket creep and elastic bolt stiffness has been useful in predicting conditions that facilitate leakage. Prior advances on this sub-class of bolted joints has lead to the development of (1) constitutive models for elastomerics, (2) initial tightening strategies, (3) etc. The effect of re-torque, which is a major consideration for typical bolted flange seals used on the Space Shuttle fleet, has not been fully characterized, however. The current study presents a systematic approach to characterizing bolted joint behavior as the consequence of sequentially applied torques. Based on exprimenta1 and numerical results, the optimal re-torquing parameters have been identified that allow for the negligible load loss after pre-load application

  18. Preloading of bolted connections in nuclear reactor component supports

    Energy Technology Data Exchange (ETDEWEB)

    Yahr, G T

    1984-10-01

    A number of failures of threaded fasteners in nuclear reactor component supports have been reported. Many of those failures were attributed to stress corrosion cracking. This report discusses how stress corrosion cracking can be avoided in bolting by controlling the maximum bolt preloads so that the sustained stresses in the bolts are below the level required to cause stress corrosion cracking. This is a basic departure from ordinary bolted joint design where the only limits on preload are on the minimum preload. Emphasis is placed on the importance of detailed analysis to determine the acceptable range of preload and the selection of a method for measuring the preload that is sufficiently accurate to ensure that the preload is actually within the acceptable range. Procedures for determining acceptable preload range are given, and the accuracy of various methods of measuring preload is discussed.

  19. Navigated placement of iliac bolts: description of a new technique.

    Science.gov (United States)

    Garrido, Ben J; Wood, Ken E

    2011-04-01

    Image navigation has improved the safety and ability to perform complex spinal procedures where visibility is not optimal or anatomic deformity is present. Numerous published studies are available demonstrating its effectiveness in improved pedicle screw placement in complex multiplanar deformities. Studies have also demonstrated image navigation technology versatility; however, stabilization of the lumbopelvic junction with navigated iliac bolt fixation has not been reported. To describe an innovative versatile application of image navigation technology in spine surgery. We examine the safety, accuracy, and effectiveness of navigated iliac bolt placement while minimizing challenges associated with current techniques. Case series. Five patients requiring lumbopelvic fixation for multiple indications, including lumbosacral pseudoarthrosis, complex sacral fracture patterns, compromised revision sacral fixation, and as an adjunct to degenerative deformity with multilevel fusion, underwent navigated iliac bolt placement. Accurate placement was verified using intraoperative computed tomography (CT) imaging using O-ARM (Medtronic, Inc.) after placement. Five patients requiring lumbopelvic fixation have undergone navigated iliac bolt placement using Medtronic Stealth Station Treon in conjunction with the O-ARM (Medtronic, Inc.). A right percutaneous posterior superior iliac spine (PSIS) reference frame was placed at the superior lateral margin of the PSIS, and bilateral iliac bolts were placed via navigation using both the anatomic and traditional surgical techniques. Both techniques were performed without direct notch palpation and minimal soft-tissue exposure. Postplacement intraoperative CT imaging was obtained to confirm position and trajectory of the bolts using O-ARM (Medtronic, Inc.). Ten iliac bolts were successfully placed in five patients. Intraoperative CT demonstrated ideal iliac screw bone placement projecting within 2 cm over sciatic notch, between pelvic

  20. What Makes Usain Bolt Unique as a Sprinter?

    Science.gov (United States)

    Shinabargar, A. J.; Hellrich, Matt; Baker, Blane

    2010-01-01

    For both casual and avid fans alike, Olympic and other sporting events can provide a wealth of data for simple physics analyses. One of the most impressive performances in recent Olympic history is that of Usain Bolt in the track-and-field sprinting events during the 2008 Summer Games. Over a seven-day span, Bolt set world records in the 100-m and…

  1. Mechanical Behaviour of Bolted Joints Under Impact Rates of Loading

    Science.gov (United States)

    2012-01-01

    P., Pascoe , K., Polak, C., & Stroud, D. (1986). The Behaviour of Single-Lap Bolted Joints in CFRP Laminates. Composite Structures, 41-55...Interferometry. J Nondestruct Eval, 135-142. Smith, P., Pascoe , K., Polak, C., & Stroud, D. (1986). The Behaviour of Single-Lap Bolted Joints in...in [Kretsis & Matthews, 1985], [Smith, Pascoe , Polak, & Stroud, 1986],[Godwin & Matthews, 1980] UNCLASSIFIED UNCLASSIFIED implies that under

  2. Response surface reconciliation method of bolted joints structure

    Directory of Open Access Journals (Sweden)

    Yunus Mohd Azmi

    2017-01-01

    Full Text Available Structural joining methods such as bolted joints are commonly used for the assembly of structural components due to their simplicity and easy maintenance. Understandably, the dynamic characteristic of bolted joined structure is mainly influenced by the properties of their joints such as preload on the bolts and joints stiffness which alter the measured dynamics response of the structure. Therefore, the need to include the local effect of the bolted joints into the numerical model of the bolted joined structure is vitally important in order to represent the model accurately. In this paper, a few types of connector elements that can be used to represent the bolted joints such as CBAR, CBEAM and CELAS have been investigated numerically and experimentally. The initial numerical results of these element connectors are compared with the experimental results in term of natural frequencies and mode shapes. The comparative evaluation of numerical and the experimental data are performed in order to provide some insights of inaccuracies in the numerical model due to invalid assumption in the numerical modelling such as geometry, material properties, and boundary conditions. The discrepancies between both results (numerical and experimental data are then corrected using the response surface reconciliation method (RSRM through which the finite element model is altered in order to provide closer agreement with the measured data so that it can be used for subsequence analysis.

  3. Effect of bolting on roadway support in extremely weak rock.

    Science.gov (United States)

    Li, Qinghai; Shi, Weiping; Qin, Zhongcheng

    2016-01-01

    In mine roadway support operations, floor bolting not only played a role in floor heave control, but also in reinforcing roof and its two sides. Correspondingly, bolting of roof and two sides also played a part in floor heave control. To quantify the effect of such bolting, based on roadway support in extremely weak rock, three physical models were produced and tested in laboratory. Through comparison of their displacements in three physical simulation experiments, the reinforcing effect of bolting in extremely weak rock roadways was quantified. Reinforcing coefficients was defined as displacement ratio between original support and new support regime. Results indicated that the reinforcing coefficients, for bolting of roof and its two sides, on floor, two sides, and roof reached 2.18, 3.56, and 1.81 respectively. The reinforcing coefficients for floor bolting on floor, two sides, and roof reached 3.06, 2.34, and 1.39 respectively. So in this extremely weak rock, the surrounding rock should be considered as an integral structure in any support operation: this allows for better local strength improvement, and provided future design guidance.

  4. Divide and Pacify

    DEFF Research Database (Denmark)

    Vanhuysse, Pieter

    by pointing to deeper political motives and wider sociological consequences. Divide and Pacify was nominated for the American Sociological Association's Award for Distinguished Contribution to Scholarship 2006, Section on Political Sociology. Praise and reviews: "Pieter Vanhuysse…is a political scientist...... across many settings in which democratic governments face the task of implementing costly reforms in complex and uncertain policy environments." –János Kornai, Harvard University "Divide and Pacify contains a provocative thesis about the manner in which political strategy was used to consolidate...... policy." - Kenneth Shepsle, Professor, Harvard University and Fellow, American Academy of Sciences "In post-communist Europe, international advice—for example from the International Monetary Fund and the World Bank—to reforming governments focused heavily on economic policy. The political imperative...

  5. Tests and analysis of mechanical behaviours of rock bolt components for China’s coal mine roadways

    Institute of Scientific and Technical Information of China (English)

    Hongpu Kang; Jinghe Yang; Xianzhi Meng

    2015-01-01

    A series of laboratory tests were performed to study the mechanical behaviours of newly developed high strength rock bolt components, including rebar, thread, plate, and domed washer. The characteristics of deformation and damage of each component were presented. The stress distribution of plate and domed washer was investigated through finite element modelling. The numerical results show that the yield and tensile strengths of the developed high strength rebar are 33.6%e58.3% and 17.2%e28.7% greater than those of the conventional rebar, respectively. The increase in yield strength was higher than that in tensile strength, suggesting an increase in yield to tensile strength ratio and a decrease in elongation. It is well-known that the thread processing may not be of high precision and accuracy as expected, which is characterised as rough thread surface, non-identical tooth height, toe stripping, and cracks in the surface. Hardening during thread processing tends to increase the thread yield and tensile strengths. In this paper, the typical deformation process of arch-shaped plate is classified into five stages. The tested plates exhibited distinct deformation characteristics and bearing capacities due to variations in shape, size, material and presence of washer. It was observed that uneven bottom surface, low bearing arch and large radius of the transitional arc connecting bearing arch and bottom surface were the major reasons ac-counting for low load-bearing capacity of plates. The performance of domed washer has a close relation with the shape, size, strength, and deformation compatibility with plate. Stress concentration was observed on the periphery of the contact surface between domed washer and plate, which is significantly influenced by the strength of domed washer and is considered to be 20%e30%higher than that of plate. Finally, a case study in the Datong coal mining district was presented, and the support pattern and effect of the developed rock bolt

  6. Bolt study - behaviour of bolts in drop accident scenarios of the Nirex 3m{sup 3} Box ILW package

    Energy Technology Data Exchange (ETDEWEB)

    Turner, G. [United Kingdom Nirex Ltd., Harwell (United Kingdom); Tso, C.F. [Arup, London (United Kingdom)

    2004-07-01

    The mission of Nirex is to provide the UK with safe, environmentally sound and publicly acceptable options for the long-term management of radioactive materials. One of the key tasks is to ensure that waste is packaged by waste producers in a form which is suitable for safe storage, transport, handling and potential disposal. In pursuit of this key requirement, Nirex has developed specifications to set the standard for the design and performance of waste packages, and has developed standard containers for the packaging of intermediate level (ILW) and some low level waste (LLW) - one of these is the 3m{sup 3} Box for immobilised operational and decommissioning ILW. The dimension envelope of this package is 1716 mm x 1716 mm in plan with 430 mm corner radii, 1226 mm tall. The maximum loaded weight is 12 tonnes. A generic design of this container has been developed, which is a welded structure manufactured from austenitic stainless steel (EN 10088-2 steel number 1.4404). The lid is connected to the body by 28 stainless steel bolts. An extensive study was carried out to develop a robust FE model of the bolts. The specific focus of this work was to use improved bolt modelling to optimize the design of the 3m{sup 3} Box, although this work could be applied to other bolted containers. This paper presents a summary of the findings from the study as follows: 1. Development of a FE bolt model for application in a 3m{sup 3} Box model. 2. Development and execution of a bolt testing programme which included tensile and shear tests on a total of 88 bolts, representing four grades of stainless steel materials, three thread sizes, and two geometries at three strain rates. 3. Benchmarking of the FE bolt model that can be used with confidence in simulating waste package behaviour in drop scenarios.

  7. Bolt study - behaviour of bolts in drop accident scenarios of the Nirex 3m{sup 3} Box ILW package

    Energy Technology Data Exchange (ETDEWEB)

    Turner, G. [United Kingdom Nirex Ltd., Harwell (United Kingdom); Tso, C.F. [Arup, London (United Kingdom)

    2004-07-01

    The mission of Nirex is to provide the UK with safe, environmentally sound and publicly acceptable options for the long-term management of radioactive materials. One of the key tasks is to ensure that waste is packaged by waste producers in a form which is suitable for safe storage, transport, handling and potential disposal. In pursuit of this key requirement, Nirex has developed specifications to set the standard for the design and performance of waste packages, and has developed standard containers for the packaging of intermediate level (ILW) and some low level waste (LLW) - one of these is the 3m{sup 3} Box for immobilised operational and decommissioning ILW. The dimension envelope of this package is 1716 mm x 1716 mm in plan with 430 mm corner radii, 1226 mm tall. The maximum loaded weight is 12 tonnes. A generic design of this container has been developed, which is a welded structure manufactured from austenitic stainless steel (EN 10088-2 steel number 1.4404). The lid is connected to the body by 28 stainless steel bolts. An extensive study was carried out to develop a robust FE model of the bolts. The specific focus of this work was to use improved bolt modelling to optimize the design of the 3m{sup 3} Box, although this work could be applied to other bolted containers. This paper presents a summary of the findings from the study as follows: 1. Development of a FE bolt model for application in a 3m{sup 3} Box model. 2. Development and execution of a bolt testing programme which included tensile and shear tests on a total of 88 bolts, representing four grades of stainless steel materials, three thread sizes, and two geometries at three strain rates. 3. Benchmarking of the FE bolt model that can be used with confidence in simulating waste package behaviour in drop scenarios.

  8. Genetic analysis of bolting after winter in sugar beet (Beta vulgaris L.).

    Science.gov (United States)

    Pfeiffer, Nina; Tränkner, Conny; Lemnian, Ioana; Grosse, Ivo; Müller, Andreas E; Jung, Christian; Kopisch-Obuch, Friedrich J

    2014-11-01

    This study reveals for the first time a major QTL for post-winter bolting resistance in sugar beet ( Beta vulgaris L.). The knowledge of this QTL is a major contribution towards the development of a winter sugar beet with controlled bolting behavior. In cool temperate climates, sugar beets are currently grown as a spring crop. They are sown in spring and harvested in autumn. Growing sugar beet as a winter crop with an extended vegetation period fails due to bolting after winter. Bolting after winter might be controlled by accumulating genes for post-winter bolting resistance. Previously, we had observed in field experiments a low post-winter bolting rate of 0.5 for sugar beet accession BETA 1773. This accession was crossed with a biennial sugar beet with regular bolting behavior to develop a F3 mapping population. The population was grown in the greenhouse, exposed to artificial cold treatment for 16 weeks and transplanted to the field. Bolting was recorded twice a week from May until October. Post-winter bolting behavior was assessed by two different factors, bolting delay (determined as days to bolt after cold treatment) and post-winter bolting resistance (bolting rate after winter). For days to bolt, means of F3 families ranged from 25 to 164 days while for bolting rate F3 families ranged from 0 to 1. For each factor one QTL explaining about 65% of the phenotypic variation was mapped to the same region on linkage group 9 with a partially recessive allele increasing bolting delay and post-winter bolting resistance. The results are discussed in relation to the potential use of marker-assisted breeding of winter sugar beets with controlled bolting.

  9. Bridging the Digital Divide

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    2002-01-01

    The article concerns the digital divide, meaning the social inequity in the access and the opportunities for gaining competencies with ICT (information and communication technologies). Problematic issues are highlighted in relation to experiences during visits to several Computer Clubhouses......, a network of multimedia workshops for youth in the USA. There are references to the learning philosophy Constructionism, which originates from MIT Media Lab and is the basis for the Computer Clubhouse project. Abstract : The consortium for Math and Science at Learning Lab Denmark and the Ministry...... of significant European initiatives promoting the recruitment and quality of the science and technology educations....

  10. CROSSING THE GREAT DIVIDE

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The safety and quality standards divide is the most severe challenge facing China’s toy industry China was blamed a spate of toy recalls this year.Overseas customers and press pointed the finger at China’s toy makers who had manu- factured toys according to their con- tracts.It was later found that most of the toy problems came from design faults of brand holders,not from Chinese manufacturers. To Wei Chuangzhong,Vice Minister of the General Administration of Quality Supervision,Inspection and Quarantine (AQSIQ),the cavalcade of negative press coverage overseas has been unfair and bad for China’s manufacturers.

  11. Failure behavior for composite single-bolted joints in double shear tension

    Science.gov (United States)

    Tang, Zhanwen; Liu, Hanyang; Yang, Zhiyong; Shi, Hanqiao; Sun, Baogang

    2016-05-01

    In order to improve the reliability and load carrying capacity of composite laminates structures which were lap jointed by bolt, in this paper, the failure strength and failure mode of laminated composite pinned-joints is investigated. To determine the effects of joint geometry and stacking sequence on the bearing strength and damage mode, the multi-scale numerical model combining with the Generalized Method of Cells (GMC) and considering the failure and the damage of constituent materials was created based on the ABAQUS and its user subroutine (USDFLD). A three-dimensional finite element technique was used for the stress analysis. Based on the three-dimensional state of stress of each element, different failure modes were detected by the failure theories of constituent materials, all of which are applied at the fiber, matrix and fiber-matrix interface constituent level. Numerical simulations have been carried out by which edge distance-to-hole diameter ratio, and plate width-to-hole diameter ratio are varied, The composite laminated plates are stacked with the following four different orientations: [+45/-45]2s, [90/+45/-45]s, and [0/90/0]s, the results show that failure mode and bearing strength are closely related to by stacking sequence of plates and geometrical parameters. Finally, the ultimate strength and failure modes of composite bolted joints in static tension double-shear loading conditions are predicted by using the progressive damage method established and the effects of layup and dimension of laminates on the properties of the connection structure were researched in this paper. An excellent agreement is found between data obtained from this study and the experiment.

  12. Monitoring the Digital Divide

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, Les

    2003-05-28

    It is increasingly important to support the large numbers of scientists working in remote areas and having low bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste, a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent ''Recommendations of Trieste'' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work.

  13. Guideline for bolted joint design and analysis : version 1.0.

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Kevin H.; Morrow, Charles W.; Durbin, Samuel; Baca, Allen

    2008-01-01

    This document provides general guidance for the design and analysis of bolted joint connections. An overview of the current methods used to analyze bolted joint connections is given. Several methods for the design and analysis of bolted joint connections are presented. Guidance is provided for general bolted joint design, computation of preload uncertainty and preload loss, and the calculation of the bolted joint factor of safety. Axial loads, shear loads, thermal loads, and thread tear out are used in factor of safety calculations. Additionally, limited guidance is provided for fatigue considerations. An overview of an associated Mathcad{copyright} Worksheet containing all bolted joint design formulae presented is also provided.

  14. A Method to Capture Macroslip at Bolted Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, Ronald Neil; Heitman, Lili Anne Akin

    2015-10-01

    Relative motion at bolted connections can occur for large shock loads as the internal shear force in the bolted connection overcomes the frictional resistive force. This macroslip in a structure dissipates energy and reduces the response of the components above the bolted connection. There is a need to be able to capture macroslip behavior in a structural dynamics model. A linear model and many nonlinear models are not able to predict marcoslip effectively. The proposed method to capture macroslip is to use the multi-body dynamics code ADAMS to model joints with 3-D contact at the bolted interfaces. This model includes both static and dynamic friction. The joints are preloaded and the pinning effect when a bolt shank impacts a through hole inside diameter is captured. Substructure representations of the components are included to account for component flexibility and dynamics. This method was applied to a simplified model of an aerospace structure and validation experiments were performed to test the adequacy of the method.

  15. Mechanical Behavior of CFRP Lattice Core Sandwich Bolted Corner Joints

    Science.gov (United States)

    Zhu, Xiaolei; Liu, Yang; Wang, Yana; Lu, Xiaofeng; Zhu, Lingxue

    2017-02-01

    The lattice core sandwich structures have drawn more attention for the integration of load capacity and multifunctional applications. However, the connection of carbon fibers reinforced polymer composite (CFRP) lattice core sandwich structure hinders its application. In this paper, a typical connection of two lattice core sandwich panels, named as corner joint or L-joint, was investigated by experiment and finite element method (FEM). The mechanical behavior and failure mode of the corner joints were discussed. The results showed that the main deformation pattern and failure mode of the lattice core sandwich bolted corner joints structure were the deformation of metal connector and indentation of the face sheet in the bolt holes. The metal connectors played an important role in bolted corner joints structure. In order to save the calculation resource, a continuum model of pyramid lattice core was used to replace the exact structure. The computation results were consistent with experiment, and the maximum error was 19%. The FEM demonstrated the deflection process of the bolted corner joints structure visually. So the simplified FEM can be used for further analysis of the bolted corner joints structure in engineering.

  16. Experimental and Numerical Investigations of Fretting Fatigue Behavior for Steel Q235 Single-Lap Bolted Joints

    Directory of Open Access Journals (Sweden)

    Yazhou Xu

    2016-01-01

    Full Text Available This work aims to investigate the fretting fatigue life and failure mode of steel Q235B plates in single-lap bolted joints. Ten specimens were prepared and tested to fit the S-N curve. SEM (scanning electron microscope was then employed to observe fatigue crack surfaces and identify crack initiation, crack propagation, and transient fracture zones. Moreover, a FEM model was established to simulate the stress and displacement fields. The normal contact stress, tangential contact stress, and relative slipping displacement at the critical fretting zone were used to calculate FFD values and assess fretting fatigue crack initiation sites, which were in good agreement with SEM observations. Experimental results confirmed the fretting fatigue failure mode for these specimens. It was found that the crack initiation resulted from wear regions at the contact surfaces between plates, and fretting fatigue cracks occurred at a certain distance away from hole edges. The proposed FFD-N relationship is an alternative approach to evaluate fretting fatigue life of steel plates in bolted joints.

  17. TENSILE STRESS RELAXATION OF TURBINE BOLT STEELS AT HIGH TEMPERATURE

    Institute of Scientific and Technical Information of China (English)

    G.Q. Jia; H.W. Shen; Y.M. Zhu

    2004-01-01

    Stress relaxation behavior of two turbine bolt steels was evaluated by the manualcontrolled tensile stress relaxation test (TSRT) at high temperature. First, feasibility and the procedure of the manual-controlled tensile stress relaxation test (TSRT) is discussed and carried out on a general creep testing machine. And then, the experimental results from such type of test were compared to the existing data provided by certain Laboratory U.K. Overall good agreement between the results of manualcontrolled TSRT method and the existing data provides confidence in the use of the proposed method in practice. Finally, the experimental results of turbine bolt steels from TSRT were compared with that of bending test. It is observed that great difference exists between the results from two different type stress relaxation tests. It is therefore suggested that the results from TSRT method be adopted in turbine bolt design in engineering.

  18. Probabilistic Evaluation of Bolted Joints in Polymer Matrix Composites

    Science.gov (United States)

    Chamis, C. C.; Minnetyan, L.

    1997-01-01

    Computational methods are described to probabilistically simulate fracture in bolted composite structures. Progressive fracture is simulated via an innovative approach independent of stress intensity factors and fracture toughness. The effect on structure damage of design variable uncertainties is quantified. The Fast Probability Integrator is used to assess the scatter in the composite structure response before and after damage. Sensitivity of the response to design variables is evaluated. The methods are demonstrated for bolted joint polymer matrix composite panels under end loads. The effects of fabrication process are included in the simulation of damage in the bolted panel. The results show that the most effective way to reduce the end displacement at fracture is to control the load and ply thickness.

  19. Why do bacteria divide?

    Directory of Open Access Journals (Sweden)

    Vic eNorris

    2015-04-01

    Full Text Available The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life – Life as independent of its constituents – is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass – its cellular connectivity – would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity – Life on the Scales of Equilibria – is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium and non-equilibrium cellular compounds and structures appropriate for survival and growth, respectively, alias `hyperstructures'. The corollary is that the cell senses both the quantity of equilibrium material and the intensity of use of non-equilibrium material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence – Competitive Coherence – is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell’s contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics

  20. Why do bacteria divide?

    Science.gov (United States)

    Norris, Vic

    2015-01-01

    The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life - Life as independent of its constituents - is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass - its cellular connectivity - would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity - Life on the Scales of Equilibria - is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium (E) and non-equilibrium (NE) cellular compounds and structures appropriate for survival and growth, respectively, alias 'hyperstructures.' The corollary is that the cell senses both the quantity of E material and the intensity of use of NE material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence - Competitive Coherence - is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell's contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics to the cell cycle itself.

  1. Stress Evolution in Roadway Rock Bolts During Mining in a Fully Mechanized Longwall Face, and an Evaluation of Rock Bolt Support Design

    Science.gov (United States)

    Zhang, Kai; Zhang, Guimin; Hou, Rongbin; Wu, Yu; Zhou, Hongqi

    2015-01-01

    Rock bolts are widely used in coal mines throughout China. Approximately 8,000 km of roadways are excavated in coal mines every year in China, 80 % of which are supported by rock bolts. At present, the design of rock bolt support schemes is mainly based on analogies and experience from previous projects. In the present study, in order to evaluate the design of rock bolt support in roadways, several cross sections of a roadway were monitored for rock bolt stress during the roadway excavation and mining. The study results show that the stress in the rock bolts varied in the areas 20 m behind the excavating face and 30 m ahead of the mining face. For the rock bolts observed in this study, the max axial force was within the design limit of the bolts, thus the support design was shown to be acceptable. Then, numerical simulation was performed using FLAC3D to investigate the stress evolution in the rock bolts during the mining of the fully mechanized longwall face. The simulation results show an overall agreement with the in situ measurements. Finally, parametric study pertaining to length, anchorage length, and rock bolt spacing was carried out with the numerical model, and several suggestions for the support design were proposed.

  2. The strength of Glued-in Bolts after 9 Years In Situ Loading

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Damkilde, Lars;

    1996-01-01

    An experimental determination of the remaining strength of glued-in bolts after 9 years is presented. The hollow tapered bolts served as the blade to rotor hub connection of a windmill with wooden blades. The test method is presented along with the load history of the bolts, the recorded residual...

  3. Analytical Study of the Mechanical Behavior of Fully Grouted Bolts in Bedding Rock Slopes

    Science.gov (United States)

    Liu, C. H.; Li, Y. Z.

    2017-09-01

    Bolting is widely used as a reinforcement means for rock slopes. The support force of a fully grouted bolt is often provided by the combination of the axial and shear forces acting at the cross section of the bolt, especially for bedding rock slopes. In this paper, load distribution and deformation behavior of the deflecting section of a fully grouted bolt were analyzed, and a structural mechanical model was established. Based on force method equations and deformation compatibility relationships, an analytical approach, describing the contribution of the axial and shear forces acting at the intersection between the bolt and the joint plane to the stability of a rock slope, was developed. Influence of the inclination of the bolt to the joint plane was discussed. Laboratory tests were conducted with different inclinations of the bolt to the joint plane. Comparisons between the proposed approach, the experimental data and a code method were made. The calculation results are in good agreement with the test data. It is shown that transverse shear resistance plays a significant role to the bolting contribution and that the bigger the dip of the bolt to the joint plane, the more significant the dowel effect. It is also shown that the design method suggested in the code overestimates the resistance of the bolt. The proposed model considering dowel effect provides a more precise description on bolting properties of bedding rock slopes than the code method and will be helpful to improve bolting design methods.

  4. STRESS-STRAIN FINITE ELEMENT ANALYSIS AND FATIGUE LIFE PREDICTION FOR BOLTED CONNECTIONS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A cyclic plasticity model is used into finite element (FE) method to obtain the details of elastic-plastic stress-strain in the bolts under cyclic axial loading. Two criteria in multiaxial fatigue are employed to predict fatigue lives of bolts. The predicted fatigue lives are in favorable agreement with the experimental results for machined bolts.

  5. NASA's Radio Frequency Bolt Monitor: A Lifetime of Spinoffs

    Science.gov (United States)

    2005-01-01

    This story begins in the 1970s, when Dr. Joseph Heyman, a young scientist at NASA s Langley Research Center, was asked to support the investigation of a wind tunnel accident at a sister center. Although the work was outside of his physics background, it sparked a research focus that guided his lengthy NASA career and would earn him a slew of accolades, including NASA s highest award medals for Exceptional Leadership, Exceptional Achievement, and Exceptional Service; the coveted Silver Snoopy Astronaut Award for Space Shuttle Return to Flight; and the Arthur Fleming Award for being one of the Top Ten Federal Scientists in Government Service. He won 30 additional NASA awards, including the Agency s Invention of the Year and the Agency s highest award for technology transfer, and was the only person to ever win 4 R&D 100 Awards. Back in 1973, though, Heyman was a young civil servant with a background in physics who was asked to sit on an accident review panel. The panel met at Ames Research Center, in Moffet Field, California, and after considerable investigation, concluded that a high-pressure pebble heater used for heating gas had failed, due to improperly tightened bolts in a 1,000-pound gate valve control section. The accident showered the facility with incendiary ceramic spheres and nearly a ton of metal, but, luckily, caused no injuries. Heyman returned to Langley and began work on a solution. He developed an ultrasonic device that would measure bolt elongation, as opposed to torque, the factor typically measured in testing bolt preload or tension. Torque measurement can lead to load errors, with miscalculations as high as 80 percent that can be passed over during installation. Bolt stretch, however, is nearly always accurate to 1 percent or better. Within 1 month, he had an acoustic resonance solution that accurately determined bolt elongation. He assumed his work on this project had ended, but it was actually the start of nearly 15 years of work perfecting

  6. Residual Strength of Glued-in Bolts After 9 Years In Situ Loading

    DEFF Research Database (Denmark)

    Pedersen, Martin Bo Uhre; Clorius, Christian Odin; Damkilde, Lars

    1996-01-01

    developed is presented along with the load history of the bolts, the recorded residual strength, the observed fracture modes and the obtained force displacement curves. A total of 11 bolts were pulled out between undamaged bolts. The mean strength of these bolts was found to be 362 kN with a standard...... deviation of 37 kN. Comparing this mean residual strength with previously recorded test data reveals a 5% strength reduction. The force displacement curves shows no plastic capacity in the connections. At fracture, a displacement between 0.4 mm and 1.0 mm was observed. In the majority of failures the bolts...

  7. Evaluation of Roof Bolting Requirements Based on In-Mine Roof Bolter Drilling

    Energy Technology Data Exchange (ETDEWEB)

    Syd S. Peng

    2005-10-01

    Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on this information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. For the prediction of roof geology and stability condition in real time, a micro processor was used and a program developed to monitor and record the drilling parameters of roof bolter. These parameters include feed pressure, feed flow (penetration rate), rotation pressure, rotation rate, vacuum pressure, oil temperature of hydraulic circuit, and signals for controlling machine. From the results of a series of laboratory and underground tests so far, feed pressure is found to be a good indicator for identifying the voids/fractures and estimating the roof rock strength. The method for determining quantitatively the location and the size of void/fracture and estimating the roof rock strength from the drilling parameters of roof bolter was developed. Also, a set of computational rules has been developed for in-mine roof using measured roof drilling parameters and implemented in MRGIS (Mine Roof Geology Information System), a software package developed to allow mine engineers to make use of the large amount of roof drilling parameters for predicting roof geology properties automatically. For the development of roof bolting criteria, finite element models were developed for tensioned and fully grouted bolting

  8. Controllable theory and applications for the wall bolting reinforcement in the roadway of seam

    Institute of Scientific and Technical Information of China (English)

    TAN Yun-liang; ZHANG Li-jun; XIAO Ya-xun

    2007-01-01

    By using the Radar penetrating technology and numerical simulations, the fractured zone could be easily determined. Both wall fractured zone and mining action of coal seam roadway were considered, and the bolt reinforcing criteria for wall including low limit condition and up limit condition were put up, which supply a basis for the bolt reinforcement design. For a particular engineering, there existed a bolt reinforcing controllable range which can be determined by the method put up in this paper. For the out of controllable range of bolt reinforcement in engineering, it is necessary to seek for other kind reinforcing technology, because the bolt reinforcing technology is not omnipotent.

  9. A novel ultrasonic method to quantify pressure in bolted joints

    Science.gov (United States)

    Sisman, A.; Martinez, J.; Guldiken, R.

    2012-12-01

    In structures most of fasteners are not critical for rigidity, however significant damage can occur if majority of uncritical fasteners fail. Furthermore, the maintenance is not feasible due to their vast quantity. In this study, we explored a new method to significantly improve the maintenance capability for these fasteners. The method distantly detects the preload between the bolt and the surface. We use a linear transducer array that generates acoustic beam using surface acoustic waves (SAWs) transmitted by array elements. The bolt boundary reflects SAW and array elements receive the echo signals. The signals are processed in the beamformer to generate the boundary's image which quantifies the preload to enable a strong estimation about the health of the bolted joint. We experimentally investigated the proposed method by using used a 5-MHz, 50-elements synthetic array. We measured the preload for five different tightening levels. As expected, two saturation regions (for too tightening and too loosening cases) and a linear region are observed (between them). The electronically steering of the array enables to make simultaneous preload measurements of many bolted joints in the same surface. The distant pressure measurement sensor could be integrated to a data acquisition system to track the health of the joints over time.

  10. Hollo-Bolt®: Blind Connector for Structural Steelwork

    OpenAIRE

    ECT Team, Purdue

    2008-01-01

    Structural steel connections for connecting to square, rectangular or circular structural tube or to conventional steel where access is available from one side only poses problems. A technology was needed which could provide a quicker and tidier installation than traditional methods such as welding, unsightly strapping or drilling and tapping holes. The invention of the Hollo-Bolt® provided such a solution.

  11. 多层预拼装钢结构系统特殊连接螺栓抗剪性能试验研究%Experimental Study on a New Bolt Connnection Used in Mutti-story Fabricated Steel Structure

    Institute of Scientific and Technical Information of China (English)

    张齐; 张其林; 丁娟

    2014-01-01

    A new kind of bolt connection consisted of self-tapping steel plate and high strength bolt will be used in a multistory fabricated steel structure system .But there are no regulations on such kind of bolted con-nection .Therefore ,extensive experimental research on bolted connection was taken .The objective of the re-search was to determine the ductility and resistance of such connection .The failure mode of bolted connections could be observed in the test .The ultimate bearing capacities of friction type high-strength bolt and bearing type high-strength bolt are different due to different design provisions and both bearing capacities were dotained in this experiment .The ultimate bearing capacities were compared with that predicted by the current connec-tion provisions specified in china steel design standards .%某新型多层预拼装钢结构系统采用了钢板自攻螺纹螺栓连接形式,超出现行规范中连接类型,需进行相关试验进行论证,针对工程常用6种规格高强螺栓自攻螺纹连接进行了单个螺栓抗剪试验,研究了此种连接的抗剪破坏模式,并依据摩擦型高强螺栓及承压型高强螺栓不同的设计假定确定两种情况下的极限承载力,与规范要求承载力设计值进行比对,为该种新型螺栓连接提供设计依据。

  12. Design of floating type bolted flange connections with grp flanges

    Energy Technology Data Exchange (ETDEWEB)

    Kurz, H., E-mail: hariolf.kurz@mpa.uni-stuttgart.de [Materialpruefungsanstalt (MPA), University of Stuttgart, Pfaffenwaldring 32, D-70569 Stuttgart (Germany); Roos, E. [Materialpruefungsanstalt (MPA), University of Stuttgart, Pfaffenwaldring 32, D-70569 Stuttgart (Germany)

    2012-01-15

    The goal of the presented work is to enable plant operators in the chemical industry to design and to operate glass-reinforced-plastics (specified in the following as grp) piping with grp flanges at temperatures up to 80 Degree-Sign C, using polytetraflourethylene (PTFE) gaskets that shall replace the mandatory rubber gaskets. Various gaskets on the basis of rubber (EPDM) and PTFE were investigated in view of the boundary conditions in bolted flange connections with glass-fiber reinforced plastic flanges in compliance with DIN EN 13555. The rubber gasket and the PTFE based gasket with a PTFE-diffusion barrier meet the leakage rate criterion of TA Luft under the conditions of bolted flange connections with grp flanges. The mechanical behavior of bolted flange connections DN50 with grp flanges was investigated and is taken into consideration in a new calculation procedure, that accounts for the specific material properties of grp and thus allows higher bolt forces, what leads to increased tightness and operational reliability of the plants. This draft procedure with experimental pre-tests (already demanded in DIN 16966) is now available to design bolted flange connections with grp flanges. - Highlights: Black-Right-Pointing-Pointer In this study we identify a PTFE-gasket with an acceptable performance in grp flanges. Black-Right-Pointing-Pointer The mechanical behavior of grp flanges is examined via experiment and FEM. Black-Right-Pointing-Pointer The derivation of a design concept for grp-loose flanges is presented. Black-Right-Pointing-Pointer The design concept shows good agreement with the FE simulation and experiment. Black-Right-Pointing-Pointer Applying the design concept leads to an increase in service reliability.

  13. Wear plates control rod guide tubes top internal reactor vessel C. N. VANDELLOS II; Desgaste placas tubos guia barras de control interno superior vasija del reactor C.N. Vandellos II

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    The guide tubes for control rods forming part of the upper internals of the reactor vessel, its function is to guide the control rod to permit its insertion in the reactor core. These guide tubes are suspended from the upper support plate which are fixed by bolts and extending to the upper core plate which is fastened by clamping bolts (split pin) to prevent lateral displacement of the guide tubes, while allowing axial expansion.

  14. Finite Element Modeling and Modal Analysis of Complicated Structure with Bolted Joints

    Institute of Scientific and Technical Information of China (English)

    PU Da-yu; LIAO Ri-dong; ZUO Zheng-xing; FENG Hui-hua

    2009-01-01

    A contact bolt model is proposed as a new modeling technique to investigate the complex structure with bolted joints for modal analysis and compared with the coupled bolt model, and the test results are given. Among these models, the coupled bolt model provides the best accurate responses compared with the experimental results. The contact bolt model shows the best effectiveness and usefulness in view of operational time. The bolt models proposed in this study are adopted for a dynamic characteristic analysis of a large diesel engine consisting of several parts which are connected by many bolts. The dynamic behavior of the entire engine structure was investigated by experiment. The coupled bolt model and the contact bolt model were applied to model the assembly of engine with high preload. The experimental results are in good agreement with the finite element method (FEM) results. Compared with the other models, the contact bolt model presented in this paper is more effective and useful in view of operational time and experience of analysts.

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

    Science.gov (United States)

    Gokcen, Tahir; Skokova, Kristina A.

    2017-01-01

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

  16. Synthetical deformation analysis of anchor bolt in jointed rock mass%节理岩体锚杆的综合变形分析

    Institute of Scientific and Technical Information of China (English)

    张伟; 刘泉声

    2012-01-01

    在总结国内外对节理岩体中锚杆加固机制的试验研究和理论探讨基础上,综合考虑锚杆的切向和轴向变形能力,建立节理锚固锚杆在剪切荷载作用下的变形模型,将节理锚固锚杆的变形区划分为弹性变形段和挤压破坏段,引入表征挤压破坏段长度的变量,对锚杆与岩体的相互作用机制进行理论分析,推导了剪切荷载与剪切位移和轴向荷载与轴向位移的关系.通过分析锚杆的屈服破坏形式,得到了确定挤压破坏段长度的方法.最后,通过算例分析了挤压破坏段长度与锚杆直径、岩体强度、锚固角度等参数的关系,得到了以下结论:(1)节理锚固锚杆抗剪作用的实质是锚杆调动岩体的抗压强度抵抗节理切向荷载.在抗压强度较高的硬岩中,挤压破坏段局限于节理面附近,锚杆影响范围小;而在抗压强度较低的软岩中,挤压破坏段较大,而且会产生较大的剪切变形,锚杆影响范围较大.(2)锚杆屈服破坏形式与岩质和锚杆直径有关.硬质岩体发生剪切屈服,而较软岩体中容易发生弯曲屈服;小直径锚杆一般直接剪切屈服,而大直径锚杆可能发生弯曲屈服.锚杆屈服破坏后出现塑性铰,挤压破坏段范围在节理一侧约为直径的1~2倍,继续增加剪切荷载,挤压破坏段长度不再增大.(3)随岩质的不同,锚杆锚固节理的最优锚固角变化较大.岩质较硬时,最优锚固角度较小,反之则较大.%Based on the former experimental and theoretical researches on the reinforcement mechanisms of anchor bolt in jointed rock mass at home and abroad, and comprehensive considering of the tangential and axial deformability of anchor bolt, a deformation model of joint bolts under shear load is proposed. The deformation of joint bolts is divided into two parts: elastic deformation zone and crushing failure zone. A variable is introduced to express the length of crushing failure zone. Mechanism

  17. Bearing Stresses in Bolted Composite Joints with Different Contact Interactions.

    Directory of Open Access Journals (Sweden)

    Hilton Ahmad

    2016-04-01

    Full Text Available In a bolted joint, it has been shown to be better to model the real contact between bolt and hole than to fix the boundary of the hole edge, a practice used by most previous researchers. Master-slave interaction was implemented in ABAQUS to simulate full contact conditions. Stress distributions were plotted along net-tension plane and hole boundary. Due to geometric non-linearity, the clearance and friction coefficients used substantially effected the maximum stress on hole boundary as shown using the benchmarking work of Eriksson. A physically-based constitutive model used is based on state-of-the art fracture mechanics was used for bolted joint strength prediction. Idealized models from Hollmann were remodelled both by fixing the hole boundary (following the original author and by implementing full contact condition using CZM and XFEM. The physically-based constitutive law used independently measured of unnotched strength and fracture energy parameter for crack opening, which is calibrated from available literatures (known as apparent fracture energy. Good correlation with experimental results was found when using the real contact condition.

  18. Experimental study of friction in aluminium bolted joints

    Science.gov (United States)

    Croccolo, D.; de Agostinis, M.; Vincenzi, N.

    2010-06-01

    This study aims at developing an experimental tool useful to define accurately the friction coefficients in bolted joints and, therefore, at relating precisely the tightening torque to the bolt preloading force in some special components used in front motorbike suspensions. The components under investigation are some clamped joints made of aluminium alloy. The preloading force is achieved by applying a torque wrench to the bolt head. Some specific specimens have been appropriately designed and realized in order to study the tribological aspects of the tightening phase. Experimental tests have been performed by applying the Design of Experiment (DOE) method in order to obtain a mathematical model for the friction coefficients. Three replicas of a full factorial DOE at two levels for each variable have been carried out. The levels include cast versus forged aluminium alloy, anodized versus spray-painted surface, lubricated versus unlubricated screw, and first tightening (fresh unspoiled surfaces) versus sixth tightening (spoiled surfaces). The study considers M8x1.25 8.8 galvanized screws.

  19. Pyroshock Prediction of Ridge-Cut Explosive Bolts Using Hydrocodes

    Directory of Open Access Journals (Sweden)

    Juho Lee

    2016-01-01

    Full Text Available Pyrotechnic release devices such as explosive bolts are prevalent for many applications due to their merits: high reliability, high power-to-weight ratio, reasonable cost, and more. However, pyroshock generated by an explosive event can cause failures in electric components. Although pyroshock propagations are relatively well understood through many numerical and experimental studies, the prediction of pyroshock generation is still a very difficult problem. This study proposes a numerical method for predicting the pyroshock of a ridge-cut explosive bolt using a commercial hydrocode (ANSYS AUTODYN. A numerical model is established by integrating fluid-structure interaction and complex material models for high explosives and metals, including high explosive detonation, shock wave transmission and propagation, and stress wave propagation. To verify the proposed numerical scheme, pyroshock measurement experiments of the ridge-cut explosive bolts with two types of surrounding structures are performed using laser Doppler vibrometers (LDVs. The numerical analysis results provide accurate prediction in both the time (acceleration and frequency domains (maximax shock response spectra. In maximax shock response spectra, the peaks due to vibration modes of the structures are observed in both the experimental and numerical results. The numerical analysis also helps to identify the pyroshock generation source and the propagation routes.

  20. AN EXPERIMENTAL STUDY ON THE RELAXATION OF BOLTS

    Directory of Open Access Journals (Sweden)

    Muhammad Abid

    2015-05-01

    Full Text Available Loss of pre-load with time, commonly known as ‘Relaxation’ is an established phenomena. Behaviour of a bolted joint depends upon the pre-load in the bolts in use, not the pre-load introduced by the mechanic. Loss of pre-load is expected due to the many factors such as embedment relaxation, gasket creep, elastic interactions, and vibration loosening or stress relaxation. In a gasketed joint, due to the gasket flexibility, relaxation is always substantial during preliminary passes, as 80 to 100% loss is not uncommon in almost all the bolts, resulting in a dynamic behaviour. Pre-load in a gasketed joint is stabilized and retained to certain extent in the final passes only. In a non-gasketed joint, due to no gasket and no rotation its static behaviour is concluded. This paper highlights the factors affecting the amount of relaxation with time and presents important considerations that can reduce this. Both the short and long term relaxations are recorded and a ‘best fit’ model for relaxation behaviour is derived.

  1. Essays on the Digital Divide

    Science.gov (United States)

    Abdelfattah, Belal M. T.

    2013-01-01

    The digital divide is a phenomenon that is globally persistent, despite rapidly decreasing costs in technology. While much of the variance in the adoption and use of information communication technology (ICT) that defines the digital divide can be explained by socioeconomic and demographic variables, there is still significant unaccounted variance…

  2. The research on delayed fracture behavior of high-strength bolts in steel structure

    Science.gov (United States)

    Li, Guo dong; Li, Nan

    2017-07-01

    High-strength bolts have been widely used in power plants. However, the high-strength bolts which being employed in pumping station, steel structure and pipeline anti-whip structure have been found delayed fracture for many times in a power plant, this will affect the reliability of steel fracture and bring blow risk caused by falling objects. The high-strength bolt with delayed fracture was carried out fracture analysis, metallurgical analysis, chemical analysis, mechanical analysis, as well as bolts installation analysis, it can be comprehensively confirmed that the direct cause of high-strength bolts delayed fracture is the stress corrosion, and the root cause of high-strength bolts delayed fracture should be the improper installation at the initial and the imperfect routine anti-corrosion maintenance.

  3. Experimental Study on Methane Explosion Ignited by Sparks of Cable Bolt Breakage

    Institute of Scientific and Technical Information of China (English)

    MA Wen-ding; XU Jia-lin; ZHANG Shao-hua

    2004-01-01

    An experimental device was designed for studying methane explosion ignited by sparks of cable bolt breakage. With the methane concentration being in explosion range, a series of experiments were conducted to study the law of spark generation during cable bolt breakage and the probability of methane explosion caused by the spark. The results show that the probability of generating sparks during cable bolt breakage is 50%. The spark generated by the breakage of steel cable bolt strand can't ignite a methane explosion. A detection was carried out using infrared-ray imaging apparatus (IRIA) to measure temperature of the spark generated by cable bolt breakage. It is indicated that the maximum temperature of the spark generated by cable bolt breakage is far less than the required ignition temperature for a methane explosion.

  4. Reinforcement of Underground Excavation with Expansion Shell Rock Bolt Equipped with Deformable Component

    Science.gov (United States)

    Korzeniowski, Waldemar; Skrzypkowski, Krzysztof; Zagórski, Krzysztof

    2017-03-01

    The basic type of rock mass reinforcement method for both preparatory and operational workings in underground metal ore mines, both in Poland and in different countries across the world, is the expansion shell or adhesive-bonded rock bolt. The article discusses results of static loading test of the expansion shell rock bolts equipped with originally developed deformable component. This component consists of two profiled rock bolt washers, two disk springs, and three guide bars. The disk spring and disk washer material differs in stiffness. The construction materials ensure that at first the springs under loading are partially compressed, and then the rock bolt washer is plastically deformed. The rock bolts tested were installed in blocks simulating a rock mass with rock compressive strength of 80 MPa. The rock bolt was loaded statically until its ultimate loading capacity was exceeded. The study presents the results obtained under laboratory conditions in the test rig allowing testing of the rock bolts at their natural size, as used in underground metal ore mines. The stress-strain/displacement characteristics of the expansion shell rock bolt with the deformable component were determined experimentally. The relationships between the geometric parameters and specific strains or displacements of the bolt rod were described, and the percentage contribution of those values in total displacements, resulting from the deformation of rock bolt support components (washer, thread) and the expansion shell head displacements, were estimated. The stiffness of the yielded and stiff bolts was empirically determined, including stiffness parameters of every individual part (deformable component, steel rod). There were two phases of displacement observed during the static tension of the rock bolt which differed in their intensity.

  5. Reinforcement of Underground Excavation with Expansion Shell Rock Bolt Equipped with Deformable Component

    Directory of Open Access Journals (Sweden)

    Korzeniowski Waldemar

    2017-03-01

    Full Text Available The basic type of rock mass reinforcement method for both preparatory and operational workings in underground metal ore mines, both in Poland and in different countries across the world, is the expansion shell or adhesive-bonded rock bolt. The article discusses results of static loading test of the expansion shell rock bolts equipped with originally developed deformable component. This component consists of two profiled rock bolt washers, two disk springs, and three guide bars. The disk spring and disk washer material differs in stiffness. The construction materials ensure that at first the springs under loading are partially compressed, and then the rock bolt washer is plastically deformed. The rock bolts tested were installed in blocks simulating a rock mass with rock compressive strength of 80 MPa. The rock bolt was loaded statically until its ultimate loading capacity was exceeded. The study presents the results obtained under laboratory conditions in the test rig allowing testing of the rock bolts at their natural size, as used in underground metal ore mines. The stress-strain/displacement characteristics of the expansion shell rock bolt with the deformable component were determined experimentally. The relationships between the geometric parameters and specific strains or displacements of the bolt rod were described, and the percentage contribution of those values in total displacements, resulting from the deformation of rock bolt support components (washer, thread and the expansion shell head displacements, were estimated. The stiffness of the yielded and stiff bolts was empirically determined, including stiffness parameters of every individual part (deformable component, steel rod. There were two phases of displacement observed during the static tension of the rock bolt which differed in their intensity.

  6. Determination of rational support parameters of bolting and shotcreting with wire mesh in soft roadway

    Institute of Scientific and Technical Information of China (English)

    LIU She-yu; MA Nian-jie; LIU Shao-wei

    2005-01-01

    Based on a great number of measured data, the author put forward zonal compressive and tensile deformation mechanism of soft rock around roadway. By using self-supporting capacity of compressive zone and controlling rock deformation of tensile zone, the long bolt or short bolt group supporting form was given for different size of rock compressive zone and tensile zone. Finally, studied on the determining method of rational support parameters of bolting and shotcreting with wire mesh in different support technology.

  7. A failure analysis study on the fractured connecting bolts of a filter press

    Directory of Open Access Journals (Sweden)

    Sh. Molaei

    2015-10-01

    Full Text Available The purpose of this study was to investigate the main causes of the co-fracture of sixteen connecting bolts of a filter press cylinder–piston system. Stress state of the bolts during the service conditions has been analyzed and the failure reasons were determined from the fractography analysis and gathered information. According to the obtained results, it was concluded that the bolts had failed by the fatigue mechanism. It seems that insufficient torque was used during assembly.

  8. Improved wire stiffness with modified connection bolts in Ilizarov external frames: a biomechanical study.

    Science.gov (United States)

    Gessmann, Jan; Jettkant, Birger; Königshausen, Matthias; Schildhauer, Thomas Armin; Seybold, Dominik

    2012-01-01

    Frame stability in Ilizarov external fixators is mainly dependent on the tension of the transosseous wires, which are clamped to the ring by connection bolts. It was the purpose of this biomechanical study to investigate the holding capacity of a modified bolt design featuring a ruffled wire-bolt interface (TrueLok™) and its influence on wire stiffness in comparison with that of classic bolts featuring a smooth, unruffled wire-bolt interface. Six different ring and bolt configurations were tested using a simplified model consisting of a single ring and wire. The holding capacity at two different tightening torques (10 and 14 Nm) of classic cannulated bolts (CB) and slotted bolts (SB) was determined on Ilizarov and Taylor Spatial Frame (TSF™) rings, whereas the modified TrueLok™ CBs and SBs were used with the TrueLok™ rings. The wire stiffness was calculated via a regression analysis of the load-displacement graphs. The modified TrueLok™ bolts demonstrated significantly better slippage resistance than the classic bolts in all configurations and wire stiffness was significantly higher in the TrueLok™ frame set-ups. After maximum loading, all of the wires showed plastic deformation, including constant wire deflection and dent marks at the clamped wire ends. In conclusion, the decrease in wire stiffness can be explained mainly as a result of wire slippage, but plastic deformation and material yielding also contribute. The relatively simple modification made by roughening the wire-bolt interface results in improved holding capacity and wire stiffness. A frame that contains these modified TrueLok™ bolts should provide improved mechanical stiffness.

  9. Theoretical and experimental research on characteristics of lateral vibration for a pre-stress bolt supporting system

    Institute of Scientific and Technical Information of China (English)

    LI Qing-feng; ZHU Chuan-qu; DUAN Yu

    2009-01-01

    According to the structure and stress trait of bearing bolts,a lateral-vibration mechanics model was established for them,and the relation between lateral-vibration fre-quency and axial load was analyzed; then,lateral-vibration trait of bearing bolts was stud-ied through laboratory simulation test.The results indicate that vibration frequency of bolt support system increases as well as axial force,the detection on axial load of bolts can be made by generating lateral vibration of bearing bolts.Theoretical and experimental re-search results show that frequency method is effective for detecting the axial force of bolt support system.

  10. Degradation and failure of bolting in nuclear power plants: Volume 2: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Nickell, R.E.

    1988-04-01

    A four-year program to resolve the generic safety issue of bolting degradation and failure in nuclear power plants has developed guidelines for material selection, bolting preload control, and plant operation, as well as a realistic method for evaluating the structural integrity of bolted joints. These measures can help improve plant availability while reducing radiation exposure and costs of maintenance and inspection. This report provides the technical basis for resolution of the generic issue of bolting degradation and failure in nuclear power plants.

  11. Effects of Rock Bolting on Stress Distribution around Tunnel Using the Elastoplastic Model

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To ensure the stability of a tunnel during construction, rock bolts are usually installed, which affects the stress distribution around the tunnel.Therefore, it is necessary to study the effects of rock bolting on the stress distribution around the tunnel.In this article, the effects of rock bolting on the stress distribution around the tunnel, including the position and orientation of bolts, the overburden depths, and the bolt lengths, are simulated using the ANSYS software with an elastoplastic model.The effect of multiple bolts of 2 m and 1 m lengths on the stress distribution in the roof and on the lateral sides of a tunnel and at different overburden depths is considered.An important finding is that the tensile stress region that is very dangerous for rock in the bottom of the tunnel grows rapidly with increasing overburden depths when rock bolts are installed only in the roof or on the lateral sides of a tunnel.The determination of the length of the rock bolt used around a tunnel is dependent on the loads and the integrity of the rock mass around the tunnel.In addition, rock bolting around the tunnel can obviously reduce the coefficients and the size of the region of stress concentration, especially when installed in high-stress areas.This fact is very important and essential for the design of tunnels and ensures engineering safety in tunnel engineering.

  12. Effects of Head Size on the Performance of Twist-Off Bolts

    OpenAIRE

    Schnupp, Keith Otto

    2003-01-01

    This study examines a specific application of button-head type twist-off bolts. Currently, the Research Council on Structural Connections Specification (2000) removes the requirement for ASTM F436 washers (ASTM 2000a) under the bolt head of twist-off bolts where the head diameter equals or exceeds that of an ASTM F436 washer when oversized and slotted holes are used. The need for washers is also removed for A490 strength bolts used on steels with specified yield strengths less than 40 ksi p...

  13. Preliminary Reactor Head Bolt Design of Prototype Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Han, Insu; Koo, Gyeonghoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    As structural requirements, the reactor head is designed to withstand all of the pressure, temperatures and forces which are likely to be imposed on it. The bolts that fasten the head to the vessel flange. Design of the reactor head bolts so as to withstand the loads applied should be designed. Currently, preliminary design of the PGSFR reactor bolts is progressed. So far, we have designed and evaluated example. The number and cross-sectional areas of bolts were determined using the procedure given in ASME BPVC Section III, Division 1, Appendix E. The purpose of this study is to conduct design the number and cross-sectional area of bolts attaching the PGSFR reactor head to the reactor vessel, using the ASME procedure. In this paper, preliminary bolt design for PGSFR was carried out according to the ASME procedure. Detailed calculations were carried out for bolt root diameter = 80 mm and number of bolts Nb = 45. It should be noted that the seating pressure recommended in the ASME code is only a suggested value, not mandatory appendix E. It does not guarantee a leak-tight joint. So these quantities are needed to carry out fatigue analysis of the bolts and to assure leak tightness of the joint during operation. For the future work, the fatigue and seismic analysis will be performed.

  14. Divided by the Market, Divided by the State

    DEFF Research Database (Denmark)

    Wulfgramm, Melike; Starke, Peter

    2016-01-01

    of the individual differences, the analysis also shows, for the first time, that both high inequality and strongly redistributive policies divide public opinion along the lines of socioeconomic position. Put differently, while market inequality may be associated with less cohesive attitudes, a highly redistributive...

  15. A Redox-Mediated Modulation of Stem Bolting in Transgenic Nicotiana sylvestris Differentially Expressing the External Mitochondrial NADPH Dehydrogenase

    National Research Council Canada - National Science Library

    Yun-Jun Liu; Adriano Nunes-Nesi; Sabá V. Wallström; Ida Lager; Agnieszka M. Michalecka; Fredrik E. B. Norberg; Susanne Widell; Kenneth M. Fredlund; Alisdair R. Fernie; Allan G. Rasmusson

    2009-01-01

    .... Nicotiana sylvestris plants overexpressing potato {Solarium tuberosum) NDB1 displayed early bolting, whereas sense suppression of the same gene led to delayed bolting, with consequential changes in flowering time...

  16. Bayesian probabilistic modeling for damage assessment in a bolted frame

    Science.gov (United States)

    Haynes, Colin; Todd, Michael

    2012-04-01

    This paper presents the development of a Bayesian framework for optimizing the design of a structural health monitoring (SHM) system. Statistical damage detection techniques are applied to a geometrically-complex, three-story structure with bolted joints. A sparse network of PZT sensor-actuators is bonded to the structure, using ultrasonic guided waves in both pulse-echo and pitch-catch modes to inspect the structure. Receiver operating characteristics are used to quantify the performance of multiple features (or detectors). The detection rate of the system is compared across different types and levels of damage. A Bayesian cost model is implemented to determine the best performing network.

  17. Lightning Bolt: an ecology of imagens, noises and extremes sounds

    Directory of Open Access Journals (Sweden)

    Fabrício Lopes da Silveira

    2011-12-01

    Full Text Available The article is focused exclusively on the music video “Dracula Mountain”, by north American noise-rock band Lightning Bolt. The aim is, in fact, sufficiently restricted: to describe the video and call it in question, considering it as a counterpoint to the band sonority and musical performance. At the end, we state that the video is both a symptom and a product of a very particular and contemporary media ecology, in which musical and audiovisual products and genres, as well as musical and audiovisual consumption habits are rebuilt and (repotentialized, sometimes inverted.

  18. Heating and cooling gas-gun targets: nuts and bolts

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsen, Richard L [Los Alamos National Laboratory; Bartram, Brian D [Los Alamos National Laboratory; Gehr, Russell J [HONEYWEL FM& T; Bucholtz, Scott M [HINEYWELL FM& T

    2009-01-01

    The nuts and bolts of a system used to heat and cool gas-gun targets is described. We have now used the system for more than 35 experiments, all of which have used electromagnetic gauging. Features of the system include a cover which is removed (remotely) just prior to projectile impact and the widespread use of metal/polymer insulations. Both the cover and insulation were required to obtain uniform temperatures in samples with low thermal conductivity. The use of inexpensive video cameras to make remote observations of the cover removal was found to be very useful. A brief catalog of useful glue, adhesive tape, insulation, and seal materials is given.

  19. A critical flaw size approach for predicting the strength of bolted glass connections

    DEFF Research Database (Denmark)

    Watson, James; Nielsen, Jens Henrik; Overend, Mauro

    2013-01-01

    The use of bolted connections in glass installations is common place in contemporary architecture. However, it is difficult to predict the load bearing capacity of these connections accurately due to the several factors that influence the strength of glass in the region of the bolt hole, namely: ...

  20. The Nuts and Bolts of Michaelis-Menten Enzyme Kinetics: Suggestions and Clarifications

    Science.gov (United States)

    Silverstein, Todd

    2011-01-01

    Matthew Junker's recent article describes a useful and effective enzyme kinetics application and analogy in which students simulate enzyme activity by unscrewing nut-bolt "substrate molecules", thus, converting them into separate nuts and bolts "products". A number of suggestions and corrections are presented that improve the clarity and accuracy…

  1. MADS-Box Genes and Gibberellins Regulate Bolting in Lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Han, Yingyan; Chen, Zijing; Lv, Shanshan; Ning, Kang; Ji, Xueliang; Liu, Xueying; Wang, Qian; Liu, Renyi; Fan, Shuangxi; Zhang, Xiaolan

    2016-01-01

    Bolting in lettuce is promoted by high temperature and bolting resistance is of great economic importance for lettuce production. But how bolting is regulated at the molecular level remains elusive. Here, a bolting resistant line S24 and a bolting sensitive line S39 were selected for morphological, physiological, transcriptomic and proteomic comparisons. A total of 12204 genes were differentially expressed in S39 vs. S24. Line S39 was featured with larger leaves, higher levels of chlorophyll, soluble sugar, anthocyanin and auxin, consistent with its up-regulation of genes implicated in photosynthesis, oxidation-reduction and auxin actions. Proteomic analysis identified 30 differentially accumulated proteins in lines S39 and S24 upon heat treatment, and 19 out of the 30 genes showed differential expression in the RNA-Seq data. Exogenous gibberellins (GA) treatment promoted bolting in both S39 and S24, while 12 flowering promoting MADS-box genes were specifically induced in line S39, suggesting that although GA regulates bolting in lettuce, it may be the MADS-box genes, not GA, that plays a major role in differing the bolting resistance between these two lettuce lines.

  2. MADS-box genes and gibberellins regulate bolting in lettuce (Lactuca sativa L.

    Directory of Open Access Journals (Sweden)

    Yingyan Han

    2016-12-01

    Full Text Available Bolting in lettuce is promoted by high temperature and bolting resistance is of great economic importance for lettuce production. But how bolting is regulated at the molecular level remains elusive. Here, a bolting resistant line S24 and a bolting sensitive line S39 were selected for morphological, physiological, transcriptomic and proteomic comparisons. A total of 12204 genes were differentially expressed in S39 vs S24. Line S39 was featured with larger leaves, higher levels of chlorophyll, soluble sugar, anthocyanin and auxin, consistent with its up-regulation of genes implicated in photosynthesis, oxidation-reduction and auxin actions. Proteomic analysis identified 30 differentially accumulated proteins in lines S39 and S24 upon heat treatment, and 19 out of the 30 genes showed differential expression in the RNA-Seq data. Exogenous gibberellins (GA treatment promoted bolting in both S39 and S24, while 12 flowering promoting MADS-box genes were specifically induced in line S39, suggesting that although GA regulates bolting in lettuce, it may be the MADS-box genes, not GA, that plays a major role in differing the bolting resistance between these two lettuce lines.

  3. MADS-Box Genes and Gibberellins Regulate Bolting in Lettuce (Lactuca sativa L.)

    Science.gov (United States)

    Han, Yingyan; Chen, Zijing; Lv, Shanshan; Ning, Kang; Ji, Xueliang; Liu, Xueying; Wang, Qian; Liu, Renyi; Fan, Shuangxi; Zhang, Xiaolan

    2016-01-01

    Bolting in lettuce is promoted by high temperature and bolting resistance is of great economic importance for lettuce production. But how bolting is regulated at the molecular level remains elusive. Here, a bolting resistant line S24 and a bolting sensitive line S39 were selected for morphological, physiological, transcriptomic and proteomic comparisons. A total of 12204 genes were differentially expressed in S39 vs. S24. Line S39 was featured with larger leaves, higher levels of chlorophyll, soluble sugar, anthocyanin and auxin, consistent with its up-regulation of genes implicated in photosynthesis, oxidation-reduction and auxin actions. Proteomic analysis identified 30 differentially accumulated proteins in lines S39 and S24 upon heat treatment, and 19 out of the 30 genes showed differential expression in the RNA-Seq data. Exogenous gibberellins (GA) treatment promoted bolting in both S39 and S24, while 12 flowering promoting MADS-box genes were specifically induced in line S39, suggesting that although GA regulates bolting in lettuce, it may be the MADS-box genes, not GA, that plays a major role in differing the bolting resistance between these two lettuce lines. PMID:28018414

  4. Monitoring bolt torque levels through signal processing of full-field ultrasonic data

    Science.gov (United States)

    Haynes, Colin; Yeager, Michael; Todd, Michael; Lee, Jung-Ryul

    2014-03-01

    Using full-field ultrasonic guided wave data can provide a wealth of information on the state of a structure through a detailed characterization of its wave propagation properties. However, the need for appropriate feature selection and quantified metrics for making rigorous assessments of the structural state is in no way lessened by the density of information. In this study, a simple steel bolted connection with two bolts is monitored for bolt loosening. The full-field data were acquired using a scanning-laser-generated ultrasound system with a single surface-mounted sensor. Such laser systems have many advantages that make them attractive for nondestructive evaluation, including their high-speed, high spatial resolution, and the ability to scan large areas of in-service structures. In order to characterize the relationship between bolt torque and the resulting wavefield in this specimen, the bolt torque in each of the bolts is independently varied from fully tightened to fully loosened in several steps. First, qualitative observations about the changes in the wavefield are presented. Next, an approach to quantifying the wave transmission through the bolted joint is discussed. Finally, a method of monitoring the bolt torque using the ultrasonic data is demonstrated.

  5. Mapping of quantitative trait loci for the bolting trait in Brassica rapa under vernalizing conditions.

    Science.gov (United States)

    Wang, Y G; Zhang, L; Ji, X H; Yan, J F; Liu, Y T; Lv, X X; Feng, H

    2014-05-23

    Premature bolting can occur occasionally during spring cultivation of heading Chinese cabbage in East Asia when the plants encounter low temperatures (vernalization), leading to economic loss. Breeding bolting-resistant cultivars is the best choice for solving this problem. We looked for QTLs responsible for varietal differences in the bolting trait in Brassica rapa under environmental conditions that promote vernalization. To achieve this goal, we constructed a linkage map with 107 simple sequence repeats and 54 insertion/deletion markers based on a segregating population of 186 F2 individuals. The resulting map consisted of 10 linkage groups and covered a total length of 947.1 cM, with an average genetic distance of 5.84 cM between adjacent markers. QTL analysis of the bolting trait was performed by two phenotypic evaluations (bolting index and flowering time) based on the scores in an F2 population in the spring of 2010, and scores in F2:3 families in autumn 2010 and spring 2011, respectively. Twenty-six QTLs that controlled bolting were detected, accounting for 2.6 to 31.2% of the phenotypic variance. The detected QTLs with large effects co-localized mainly on linkage groups A02, A06, and A07. These QTLs may provide useful information for marker-assisted selection in a breeding program for late bolting or bolting-resistant cultivars in B. rapa crops.

  6. The Nuts and Bolts of Michaelis-Menten Enzyme Kinetics: Suggestions and Clarifications

    Science.gov (United States)

    Silverstein, Todd

    2011-01-01

    Matthew Junker's recent article describes a useful and effective enzyme kinetics application and analogy in which students simulate enzyme activity by unscrewing nut-bolt "substrate molecules", thus, converting them into separate nuts and bolts "products". A number of suggestions and corrections are presented that improve the clarity and accuracy…

  7. Mechanical properties and supporting effect of CRLD bolts under static pull test conditions

    Science.gov (United States)

    Sun, Xiao-ming; Zhang, Yong; Wang, Dong; Yang, Jun; Xu, Hui-chen; He, Man-chao

    2017-01-01

    A device for supporting soft rock masses combined with a constant resistance structure characterized by constant resistance and large deformation at the end of a steel bar, known as the constant resistance and large deformation (CRLD) bolt, has recently been developed to counteract soft rock swelling that often occurs during deep mining. In order to further study the mechanical properties of the CRLD bolt, we investigated its mechanical properties by comparison with the conventional strength bolt (rebar) using static pull tests on many aspects, including supporting capacity, elongation, radial deformation, and energy absorption. The tests verified that the mechanical defects of the rebar, which include the decrease of bolt diameter, reduction of supporting capacity, and emergence and evolution of fracture until failure during the whole pull process, were caused by the Poisson's ratio effect. Due to the special structure set on the CRLD bolt, the bolt presents a seemingly unusual phenomenon of the negative Poisson's ratio effect, i.e., the diameter of the constant resistance structure increases while under-pulling. It is the very effect that ensures the extraordinary mechanical properties, including high resistance, large elongation, and strong energy absorption. According to the comparison and analysis of numerical simulation and field test, we can conclude that the CRLD bolt works better than the rebar bolt.

  8. Getting Past the "Digital Divide"

    Science.gov (United States)

    McCollum, Sean

    2011-01-01

    In the last decade, "digital divide" has become a catchphrase for the stubborn disparity in IT resources between communities, especially in regard to education. Low-income, rural and minority populations have received special scrutiny as the technological "have-nots." This article presents success stories of educators who can work around obstacles…

  9. Dividing Fractions: A Pedagogical Technique

    Science.gov (United States)

    Lewis, Robert

    2016-01-01

    When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…

  10. Degradation and failure of bolting in nuclear power plants: Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Nickell, R.E.

    1988-04-01

    These two volumes provide the documentation for industry resolution of the US Nuclear Regulatory Commission (NRC) generic issue B-29, Degradation and Failure of Bolting in Nuclear Power Plants. The issue was identified as a consequence of concerns about the structural integrity of component supports circa 1980. When bolting integrity became a separate issue in 1982, the utility industry responded by forming a Task Group on Bolting under the aegis of the Atomic Industrial Forum (AIF) and the Materials Properties Council (MPC). The AIF/MPC Task Group on Bolting formulated a comprehensive nineteen-task action plan aimed at resolution of the issue, with implementation of the plan, the responsibility of EPRI and the affected Owner's Groups. EPRI organized a matrix-managed Generic Bolted Joint Integrity Program to carry out the research, with the results reported herein.

  11. EVALUATION OF TROQUE VS CLOSURE BOLT PRELOAD FOR A TYPICAL CONTAINMENT VESSEL UNDER SERVICE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.

    2010-02-16

    Radioactive material package containment vessels typically employ bolted closures of various configurations. Closure bolts must retain the lid of a package and must maintain required seal loads, while subjected to internal pressure, impact loads and vibration. The need for insuring that the specified preload is achieved in closure bolts for radioactive materials packagings has been a continual subject of concern for both designers and regulatory reviewers. The extensive literature on threaded fasteners provides sound guidance on design and torque specification for closure bolts. The literature also shows the uncertainty associated with use of torque to establish preload is typically between 10 and 35%. These studies have been performed under controlled, laboratory conditions. The ability to insure required preload in normal service is, consequently, an important question. The study described here investigated the relationship between indicated torque and resulting bolt load for a typical radioactive materials package closure using methods available under normal service conditions.

  12. Vibration Characteristic of Anchoring System of Bolt and Elastic Wave Propagation Law

    Institute of Scientific and Technical Information of China (English)

    WANG Cheng; LI Yi; NING Jian-guo; LIN Hua-chang

    2006-01-01

    Based on one-dimension wave theory, the propagation law of elastic wave along the rock bolt, rock medium and their coupling system are researched, and the attenuation law and propagation mechanism of wave in the anchoring system are obtained. Meanwhile, the studies on end reflection and dynamic response under load are also carried out experimentally, the relationship between anchoring length and excited wave length is obtained when the end reflection of bolt emerges, and it is concluded that under the condition of bolt loaded,as the load increases, the reflection of the upper interface of anchoring segment weakens while the end reflection strengthens relatively, hence the energy attenuation increases. These results provide some important theory basis for measuring the effective anchoring length of bolt, judging the bonding quality of anchoring end and surrounding rock, and estimating the utmost load force of bolt.

  13. Fasteners 1 dimensional standards for bolts, screws and studs national standards

    CERN Document Server

    2011-01-01

    This 7th edition of DIN Handbook 10 contains 90 currently valid German national standards (DIN Standards) dealing with the dimensions of bolts, screws and studs. In this updated compilation four standards are new: DIN 787 T-head bolts; DIN 1445 Clevis pins with head and threaded portion; DIN 5903-1 Fish bolts - Part 1: With round head and oval neck; DIN 5903-2 Fish bolts - Part 2: With square head. 27 standards have been revised for this edition. DIN Handbook 10 is the companion volume to DIN Handbook 362 "Fasteners 6 - Dimensional standards for bolts and screws - European Standards", which reflects the state of the art in Europe. Together, DIN Handbooks 10 and 362 provide the user with a comprehensive overview of standards in the fasteners sector.

  14. Effects of a sliding plate on morphology of the epiphyseal plate in goat distal femur.

    Science.gov (United States)

    Lin, Da-sheng; Lian, Ke-jian; Hong, Jia-yuan; Ding, Zhen-qi; Zhai, Wen-liang

    2012-01-01

    The aim of this study was to observe the effects of a sliding plate on the morphology of the epiphyseal plate in goat distal femur. Eighteen premature female goats were divided randomly into sliding plate, regular plate and control groups. Radiographic analysis and histological staining were performed to evaluate the development of epiphyseal plate at 4 and 8 weeks after surgery. In the sliding plate group, the plate extended accordingly as the epiphyseal plate grows, and the epiphyseal morphology was kept essential normal. However, the phenomenon of the epiphyseal growth retardation and premature closure were very common in the regular plate group. In addition, the sliding plate group exhibited more normal histologic features and Safranin O staining compared to the regular plate group. Our results suggest that the sliding plate can provide reliable internal fixation of epiphyseal fracture without inhibiting epiphyseal growth.

  15. Effects of a Sliding Plate on Morphology of the Epiphyseal Plate in Goat Distal Femur

    Directory of Open Access Journals (Sweden)

    Da-sheng LIN, Ke-jian LIAN, Jia-yuan HONG, Zhen-qi DING, Wen-liang ZHAI

    2012-01-01

    Full Text Available The aim of this study was to observe the effects of a sliding plate on the morphology of the epiphyseal plate in goat distal femur. Eighteen premature female goats were divided randomly into sliding plate, regular plate and control groups. Radiographic analysis and histological staining were performed to evaluate the development of epiphyseal plate at 4 and 8 weeks after surgery. In the sliding plate group, the plate extended accordingly as the epiphyseal plate grows, and the epiphyseal morphology was kept essential normal. However, the phenomenon of the epiphyseal growth retardation and premature closure were very common in the regular plate group. In addition, the sliding plate group exhibited more normal histologic features and Safranin O staining compared to the regular plate group. Our results suggest that the sliding plate can provide reliable internal fixation of epiphyseal fracture without inhibiting epiphyseal growth.

  16. Experimental Evaluation of Metal Composite Multi Bolt Radial Joint on Laminate Level, under uni Axial Tensile Loading

    Directory of Open Access Journals (Sweden)

    C Sharada Prabhakar

    2017-03-01

    Full Text Available Longitudinal tensile load exerted due to internal hydraulic pressure, on bolted radial joints between large size PAN carbon epoxy filament wound composite cylindrical section and small size 15CDV6 steel cylindrical sections, were simulated and tested on flat laminate level, mainly to check the strength of PAN carbon epoxy helical wound laminate made by wet winding method. Small segmental portion of circumference of cylindrical sections was considered as width of composite laminate and of metallic plates, necessary to accommodate 5 rows of fasteners in transverse direction with specified pitch distance. Bolted radial joints between carbon epoxy helical wound flat laminate and 15CDV6 steel plates were realized with 8 numbers of steel fasteners distributed in 3 longitudinal and 5 transverse rows at each joint. Helical angle of winding, length and thickness of carbon epoxy laminate was ±22.5°, 458mm and 11mm respectively. Length and structural thickness of radial joints, total length and width of assembly test specimen were 98mm, 18mm, 870mm and 169.43mm respectively. Joints were tested under uni-axial tensile load up to failure. Joints failed at 18 tonnes (1.7 times of design load. Failure mode was observed as initiation of bearing failure at all 8, countersink fastener holes in laminate and shear out failure at edge hole. Strains in fibre direction, at 45°and at transverse to fibre direction were found very less. Maximum compressive strain and residual strain, near fastener holes were found as -1423 and -136 micro strain respectively. Test was successful

  17. Thermo-mechanical finite element analyses of bolted cask lid structures

    Energy Technology Data Exchange (ETDEWEB)

    Wieser, G.; Qiao Linan; Eberle, A.; Voelzke, H. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2004-07-01

    The analysis of complex bolted cask lid structures under mechanical or thermal accident conditions is important for the evaluation of cask integrity and leak-tightness in package design assessment according to the Transport Regulations or in aircraft crash scenarios. In this context BAM is developing methods based on Finite Elements to calculate the effects of mechanical impacts onto the bolted lid structures as well as effects caused by severe fire scenarios. I n case of fire it might be not enough to perform only a thermal heat transfer analysis. The complex cask design in connection with a severe hypothetical time-temperature-curve representing an accident fire scenario will create a strong transient heating up of the cask body and its lid system. This causes relative displacements between the seals and its counterparts that can be analyzed by a so-called thermo-mechanical calculation. Although it is currently not possible to correlate leakage rates with results from deformation analyses directly an appropriate Finite Element model of the considered type of metallic lid seal has been developed. For the present it is possible to estimate the behaviour of the seal based on the calculated relative displacements at its seating and the behaviour of the lid bolts under the impact load or the temperature field respectively. Except of the lid bolts the geometry of the cask and the mechanical loading is axial-symmetric which simplifies the analysis considerably and a two-dimensional Finite Element model with substitute lid bolts may be used. The substitute bolts are modelled as one-dimensional truss or beam elements. An advanced two-dimensional bolt submodel represents the bolts with plane stress continuum elements. This paper discusses the influence of different bolt modelling on the relative displacements at the seating of the seals. Besides this, the influence of bolt modelling, thermal properties and detail in geometry of the two-dimensional Finite Element models on

  18. Performance of bolted closure joint elastomers under cask aging conditions

    Energy Technology Data Exchange (ETDEWEB)

    Verst, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Sindelar, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Skidmore, E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Daugherty, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-07-23

    The bolted closure joint of a bare spent fuel cask is susceptible to age-related degradation and potential loss of confinement function under long-term storage conditions. Elastomeric seals, a component of the joint typically used to facilitate leak testing of the primary seal that includes the metallic seal and bolting, is susceptible to degradation over time by several mechanisms, principally via thermo-oxidation, stress-relaxation, and radiolytic degradation under time and temperature condition. Irradiation and thermal exposure testing and evaluation of an ethylene-propylene diene monomer (EPDM) elastomeric seal material similar to that used in the CASTOR® V/21 cask for a matrix of temperature and radiation exposure conditions relevant to the cask extended storage conditions, and development of semiempirical predictive models for loss of sealing force is in progress. A special insert was developed to allow Compressive Stress Relaxation (CSR) measurements before and after the irradiation and/or thermal exposure without unloading the elastomer. A condition of the loss of sealing force for the onset of leakage was suggested. The experimentation and modeling being performed could enable acquisition of extensive coupled aging data as well as an estimation of the timeframe when loss of sealing function under aging (temperature/radiation) conditions may occur.

  19. Energy Neutral Wireless Bolt for Safety Critical Fastening.

    Science.gov (United States)

    Seyoum, Biruk B; Rossi, Maurizio; Brunelli, Davide

    2017-09-26

    Thermoelectric generators (TEGs) are now capable of powering the abundant low power electronics from very small (just a few degrees Celsius) temperature gradients. This factor along with the continuously lowering cost and size of TEGs, has contributed to the growing number of miniaturized battery-free sensor modules powered by TEGs. In this article, we present the design of an ambient-powered wireless bolt for high-end electro-mechanical systems. The bolt is equipped with a temperature sensor and a low power RF chip powered from a TEG. A DC-DC converter interfacing the TEG with the RF chip is used to step-up the low TEG voltage. The work includes the characterizations of different TEGs and DC-DC converters to determine the optimal design based on the amount of power that can be generated from a TEG under different loads and at temperature gradients typical of industrial environments. A prototype system was implemented and the power consumption of this system under different conditions was also measured. Results demonstrate that the power generated by the TEG at very low temperature gradients is sufficient to guarantee continuous wireless monitoring of the critical fasteners in critical systems such as avionics, motorsport and aerospace.

  20. Strength Analysis of Laminated and Metallic Plates Bolted Together by Many Fasteners

    Science.gov (United States)

    1986-07-01

    January 1086. Other requests for this document must be referred to AFWAL/ FIBRA , WPAFB, OHIO 48433-0883 WARNING-This document contains technical...ORGANIZATION Northrop Corporation Flight Dynamics Laboratory (AI𔃾AL/ FIBRA ) Aircraft Division ________Air Force Wright Aeronautical Laboratories Sc...Joints in Composite Structures." S2. Please contact the undersigned if you have any questions regarding this letter. G. DOBEN cc: AFWAL/ FIBRA Chief

  1. Strength Analysis of Composite and Metallic Plates Bolted Together by a Single Fastener.

    Science.gov (United States)

    1985-08-01

    FUNDING/SPONSORING a80 OFFICE SYMBOL 9 PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (I f Appheebi I See Item 7 AFWAL/FIBRA Contract F33615...obtained. The fastener analisis also computes approximate shear strain values at the inter- facial locations between adjacent plies. Incorporating

  2. Information Societies and Digital Divides

    CERN Document Server

    Sorj, Bernardo

    2008-01-01

    The book argues ICT are part of the set of goods and services that determine quality of life, social inequality and the chances for economic development. Therefore understanding the digital divide demands a broader discussion of the place of ICT within each society and in the international system. The author argues against the perspectives that either isolates ICT from other basic social goods (in particular education and employment) as well as those that argue that new technologies are luxury of a consumer society. Though the author accepts that new technologies are not a panacea for the problems of inequality, access to them become a condition of full integration of social life. Using examples mainly from Latin America, the work presents some general policy proposals on the fight against the digital divide which take in consideration other dimensions of social inequality and access to public goods. Bernardo Sorj was born in Montevideo, Uruguay. He is a naturalized Brazilian, living in Brazil since 1976. He ...

  3. Comparative Modal Analysis of Gasketed and Nongasketed Bolted Flanged Pipe Joints: FEA Approach

    Directory of Open Access Journals (Sweden)

    Muhammad Abid

    2012-01-01

    Full Text Available It is widely known that resonance can quickly lead to failure in vibrating bolted flanged pipe joints. Condition monitoring is performed time to time in some industries for smooth operation of a system, whereas mostly trial-and-error tests are performed to control vibration. During all this process, the inherent design problems are not considered. A bolted flange joint in piping system is not a simple problem, being the combination of flange, gasket, bolts, and washers. The success of a bolted flanged pipe joint is defined by the “static mode of load” in the joint. However, it has been recognized that a “dynamic mode of load” governs in a gasketed bolted flanged pipe joint, which leads to its failure due to flange rotation, providing flange yielding, fatigue of bolts, and gasket crushing. This paper presents results of detailed 3D finite element and mathematical modal analysis under bolt up to determine natural frequencies and mode shapes of gasketed flanged joints with and without raised face in comparison to the nongasketed flange joint.

  4. Alternative method for identification of the dynamic properties of bolted joints

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Tieneng [Beijing Univ. of Technology, Beijing (China); Li, Ling; Cai, Ligang; Zhao, Yong Sheng [Xi' an Univ. of Architecture Technology, Xi' an (China)

    2012-10-15

    Bolted joints often have a significant effect on the dynamical behavior of assembled mechanical structures. An accurate model of an assembled structure depends on correctly determining and identifying the dynamic parameters of bolted joints. This paper presents an alternative method for identifying these dynamic parameters using structure's natural frequency and damping. A novel experiment is designed with a test piece consisting of only bolted joints, with the governing equations of the test piece established using the analytical method. The relationships between the equivalent dynamic parameters of the bolted joints and the natural frequencies and damping ratios of the test piece are determined for both the normal and tangential directions. The parameter identification problem for bolted joints is thus transformed into a test of the natural frequency and the damping ratio of the test piece. In order to check the accuracy of the proposed identification method, the test piece and bolted joints are modeled using the finite element method (FEM) and the dynamic properties of the test piece are analyzed. The maximum error between the natural frequencies of the FEM result and the experimental values in the normal and tangential models are 4.73% and 0.34%, respectively. The result indicates that the proposed method is valid for the dynamic parameter identification of bolted joints.

  5. A Study on the Fracture Control of Rock Bolts in High Ground Pressure Roadways of Deep Mines

    Directory of Open Access Journals (Sweden)

    Wen Jinglin

    2015-01-01

    Full Text Available According to the frequent fractures of rock bolts in high ground pressure roadways of deep mines, this paper analyzes the mechanism of fractures and concludes that high ground pressure and material de-fects are main reasons for the fracture of rock bolts. The basic idea of fracture control of rock bolts in high ground pressure roadways of deep mines is to increase the yield load and the limit load of rock bolt materials and reduce the actual load of rock bolts. There are four ways of controlling rock bolt fracture: increasing the rock bolt diameter, strengthening bolt materials, weakening support rigidity and the implementation of double supporting. With the roadway support of the 2302 working face of a coal mine as the project background, this paper carries out a study on the effect of two schemes, increasing the rock bolt diameter and the double supporting technique through methods of theoretical analysis, numerical simulation and so on. It determines the most reasonable diam-eter of rock bolts and the best delay distance of secondary support. Practices indicate that rock bolt fracture can be effectively controlled through the double supporting technique, which strengthens the roof and two sides through the first supporting technique and strengthens side angles through the secondary supporting technique.

  6. Expression of NO scavenging hemoglobin is involved in the timing of bolting in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Hebelstrup, Kim Henrik; Jensen, Erik Østergaard

    2008-01-01

    -symbiotic hemoglobin gene, GLB2, in Arabidopsis thaliana. Lines with GLB1 silencing had a significant delay of bolting and after bolting, shoots reverted to the rosette vegetative phase by formation of aerial rosettes at lateral meristems. Lines with overexpression of GLB1 or GLB2 bolted earlier than wild type plants...... molecule, NO. So far, NO scavenging has only been demonstrated for class 1 non-symbiotic hemoglobins. A direct assay in Arabidopsis leaf cells shows that GLB1 as well as the class 2 non-symbiotic hemoglobin, GLB2, scavenge NO in vivo. NO has also been demonstrated to be a growth stimulating signal...

  7. Bolt-Grout Interactions in Elastoplastic Rock Mass Using Coupled FEM-FDM Techniques

    Directory of Open Access Journals (Sweden)

    Debasis Deb

    2010-01-01

    Full Text Available Numerical procedure based on finite element method (FEM and finite difference method (FDM for the analysis of bolt-grout interactions are introduced in this paper. The finite element procedure incorporates elasto-plastic concepts with Hoek and Brown yield criterion and has been applied for rock mass. Bolt-grout interactions are evaluated based on finite difference method and are embedded in the elasto-plastic procedures of FEM. The experimental validation of the proposed FEM-FDM procedures and numerical examples of a bolted tunnel are provided to demonstrate the efficacy of the proposed method for practical applications.

  8. Time-frequency analysis of guided ultrasonic waves used for assessing integrity of rock bolts

    Science.gov (United States)

    Stepinski, Tadeusz

    2017-04-01

    The purpose of this paper is to demonstrate application of the time-frequency analysis (TFA) for processing guided ultrasonic waves measured by means of a specially designed ultrasonic rock bolt tester during nondestructive inspection of rock bolts. A pulse-echo method is adopted in the instrument as the most appropriate for the in-field applications. This paper presents methods for analysis of the measured guided ultrasonic waves using the TFA. The proposed TFA methodology is first demonstrated on the simulated signals and then verified using the experimental signals gathered from grouted prepared rock bolts provided with artificial defects simulating grout discontinuities.

  9. Development of a smart rock bolt for underground monitoring operations

    CSIR Research Space (South Africa)

    Moema, JS

    2003-07-01

    Full Text Available ; this is important in order to resist extreme conditions of high tensile and shear stress, much as a conventional roof bolt. Comparisons have been made with standard grades such as Type 304 stainless steel including the work-hardening behaviour. Some preliminary... of industrial annealed smartbolt alloy………………………...7 Figure 6. Smartbolt alloy plotted on Schaefler-De Long diagram………………………8 Figure 7. Comparison of different steel grades in terms of strength and ductility combination……………………………………………………12 Figure 8. Stress...

  10. Quantum Gravity and the Nuts and Bolts of Thermodynamic Volumes

    CERN Document Server

    Johnson, Clifford V

    2014-01-01

    In theories of semi-classical quantum gravity where the cosmological constant is considered a thermodynamic variable, the gravitational mass of a black hole has been shown to correspond to the enthalpy of the thermodynamic system, rather than the energy. We propose that this should be extended to all spacetime solutions, and consider the meaning of this extension of gravitational thermodynamics for the Taub-NUT and Taub-Bolt geometries in four dimensional locally anti-de Sitter spacetime. We present formulae for their thermodynamic volumes. Surprisingly, Taub-NUT has negative volume, for which there is a natural dynamical explanation in terms of the process of formation of the spacetime. A special case corresponds to pure AdS_4 with an S^3 slicing. The same dynamical setting can explain the negative entropy known to exist for these solutions for a range of parameters.

  11. Twofold hidden conformal symmetry of Kerr-Bolt black holes

    Institute of Scientific and Technical Information of China (English)

    M.R. Setare; V. Kamali

    2012-01-01

    Previously we have shown that a four-dimensional Kerr-Bolt black hole in non-extremal and also in extremal cases could be described by a holographic two-dimensional (2D) conformal field theory (CFT) [Ghezelbash A M,Kamali V and Setare M R 2010 Phys.Rev.D 82 124051; Setare M R and Kamali V 2010 JHEP 10 074].Motivated by recent work [Chen C M,Huang Y M,Sun J R,Wu M F and Zou S J 2010 Phys.Rev.D 82 066004],we show that there is another holographic description for these black holes.The first description is called the J-picture,whose construction is based on the black hole angular momentum.The new description is called the Q-picture,whose constructions originate from the nut charge of the black hole.Similar to the previous cases [Ghezelbash A M,Kamali V and Setare M R 2010 Phys.Rev.D 82 124051; Setare M R and Kamali V 2010 JHEP 10 074],we show that this new picture for a low frequency limit of the wave equation of a massless charged scalar field in the background of a Kerr-Bolt black hole can be written as the Casimir of SL(2,R) symmetry.Our result shows that the entropy of the black hole is reproduced by the Cardy formula.In addition,the absorption cross section is consistent with the finite temperature absorption cross section for a two-dimensional CFT.

  12. A Reduced Order Model of Force Displacement Curves for the Failure of Mechanical Bolts in Tension.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Keegan J. [Univ. of Illinois, Urbana-Champaign, IL (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brake, Matthew Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    Assembled mechanical systems often contain a large number of bolted connections. These bolted connections (joints) are integral aspects of the load path for structural dynamics, and, consequently, are paramount for calculating a structure's stiffness and energy dissipation prop- erties. However, analysts have not found the optimal method to model appropriately these bolted joints. The complexity of the screw geometry causes issues when generating a mesh of the model. This report will explore different approaches to model a screw-substrate connec- tion. Model parameters such as mesh continuity, node alignment, wedge angles, and thread to body element size ratios are examined. The results of this study will give analysts a better understanding of the influences of these parameters and will aide in finding the optimal method to model bolted connections.

  13. Comparative study between 2D and 3D FEM techniques in single bolt, single lap, composite bolted joints for space structures

    Directory of Open Access Journals (Sweden)

    Calin-Dumitru COMAN

    2017-09-01

    Full Text Available Two-dimensional and three-dimensional finite element models have been developed to study the effects of bolt-hole clearance on the mechanical behavior of bolted composites (graphite/epoxy joints in space structures. The type of the studied joint was single bolt, single lap, and the geometry is a standard type for these kind of composite joints space structures. In this study, two approaches, 2D (linear analysis and 3D (nonlinear analysis were developed and the results were compared to numerical and experiment results from literature. The contact between the parts affecting the accuracy and efficiency of the models is detailed. The model’s capability to predict the three-dimensional effects such as secondary bending and through-thickness variations of the stress and stain tensor fields is presented.

  14. Stress evolution and support mechanism of a bolt anchored in a rock mass with a weak interlayer

    Institute of Scientific and Technical Information of China (English)

    Ding Shuxue; Jing Hongwen; Chen Kunfu; Xu Guo'an; Meng Bo

    2017-01-01

    By applying experimental method, the bolt stress and supporting mechanism is studied during the deformation process of a rock mass containing a weak interlayer. The force measuring bolt is installed manually and instrumented five pairs of symmetrical strain gauges. The experimental results show that the fully grouted bolt suffers tensile, compressive, bending and shear stress at the same time. The bolt stress evolution is closely related to the deformation stages of the rock mass which are very gradually varying stage, gradually varying stage at the pre-peak and suddenly varying stage at the post peak stage.The axial compressive stress in the bolt is mainly induced by the moment. Thus, in most cases the axial compressive stress is distributed on one side of the bolt. For axial stresses, induced by the axial force and the bending moment at the post-peak stage, three types of changing are observed, viz. increasingincreasing type, decreasing-increasing type and increasing-decreasing type. The stress characteristics of the bolt section in the weak interlayer are significantly different from those in the hard rock. The failure models of the anchored bolt are tensile failure and shear failure, respectively. The bolt not only provides constraints on the free surface of the rock mass, but also resists the axial and lateral loading by the bending moment. This study provides valuable guidelines for bolting support design and its safetyssessment.

  15. Oil-to-coal cavern conversion pins its success on rock bolts

    Energy Technology Data Exchange (ETDEWEB)

    Hamrin, H. (Atlas Copco MCT AB (Sweden))

    1989-07-01

    A new pressurized fluidized bed combustion power plant is being built in Stockholm. Coal will be stored underground, in old oil storage chambers. The roof had to be bolted and shotcreted and swellex bolts were used. These act as roof support with immediate action for the protection of the workers, and as a safety pin to reinforce the bond between shotcrete and the rock surface. 4 figs.

  16. Stabilization of ground movement with yield rock bolts using spatial effect

    Energy Technology Data Exchange (ETDEWEB)

    Naprasnikov, S.V.; Alexandrov, S.N.; Sazhnev, V.P.; Nazimko, V.V. [Donetsk State Technical University, Donetsk (Ukraine)

    1999-07-01

    New rock bolting technology has been developed for stabilization of roofs and floor closures in underground openings. Yield rock bolts should be inclined 5-40{degree} to the relative direction of expected roof deflection and oriented in the plane under an angle of 5-90{degree} relative to the orthogonal cross-section of the roadway. Such an orientation increases the pullout force by 2% and enhances stability of a roadway. 3 refs., 2 figs., 1 tab.

  17. On the performance of Usain Bolt in the 100 metre sprint

    CERN Document Server

    Gómez, J J Hernández; Gómez, R W

    2013-01-01

    A theoretical model of the performance of the 100 m world record sprint of Usain Bolt during the 2009 World Championships at Berlin is developed, assuming a drag force proportional to $v$ and to $v^2$. The resulting equation of motion is solved and fitted to the experimental data obtained from the International Amateur of Athletics Federations that recorded Bolt's position with a LAVEG (laser velocity guard) device. It is worth to note that our model works only for short sprints.

  18. NDE applications in an anchor bolt and sign bridge inspection program

    Science.gov (United States)

    Fish, Philip E.

    1998-03-01

    Wisconsin Department of Transportation implemented an Anchor Bolt Inspection Program and Sign Bridge Inspection Program in 1990 for cantilever & overhead sign structures, high mast light towers, interstate light towers, and signal masts. All cantilever & overhead sign structures and high mast light towers have been inspected in-depth 'hands on' during this time period while implementation of inspection continues for interstate light towers and signal masts. The program requires an experienced inspection team and a practical inspection approach. Inspection preparation includes review of all background information such as design plans, design computations, construction plans, shop plans, and maintenance history. An inspection plan is developed. Special emphasis is placed on determining type of structure, type of material, welding details. For anchor bolts, type of material, cut or rolled threads, type of coating, and method of placement are important issues. Inspection emphasis are on 'hands on' and Nondestructive evaluation. Special emphasis is placed visual conditions of sign structures and anchor bolts (cut or rolled threads, straightness, corrosion, nut tension, etc.) along with ultrasonic inspection. This program places a strong emphasis on Non Destructive Testing (NDT), especially ultrasonic. Procedures and inspection calibrations for anchor bolts, are developed from similar anchor bolt geometry and material type. Cut notches are placed in the anchor bolts at locations of possible failure. NDT inspection calibrations are performed from these bolts. Report documentation includes all design plans, pictorial documentation of structural deficiencies, sketches, nondestructive evaluation reports, conclusions, and recommendations. This program has been successful in locating critical cracks and failed members on existing sign structures and new sign structures less than six months old. Also, failed anchor bolts and critical cracks have been located on high mast light

  19. Finite element analysis on optimized arrangement of long list bolts group with high strength in steel truss bridges%钢桁桥长列高强螺栓群优选布置的有限元分析

    Institute of Scientific and Technical Information of China (English)

    朱铭; 王荣辉; 黄永辉

    2009-01-01

    针对高强螺栓群在钢桁桥中受力性能复杂、优化布置困难的问题,采用有限元软件ANSYS建立了考虑接触状态的三维有限元实体模型,对4种不同的螺栓布置方式在拉力荷载作用下的板件相对位移、板件应力以及接触面的摩擦应力分布状态等进行了模拟,并对比分析了优选前后螺栓群布置的效果.结果表明:优选布置后的螺栓拼接接头应力状态变化不大;采用优选的布置方案可节省螺栓19%~25%.%In order to solve the problem of complicated structural behavior and difficult optimum arrangement of high-strength bolts group used in steel truss bridges, a 3D solid FEM model with the consideration of contact state was established by using software ANSYS to simulate the displacement between coreplate and buttcover plate, the normal stress on the plate and frictional stress state on the contact surface of four different high-strength bolts arrangements under tension force. The optimized effect was compared to the one before being optimized. The calculation results show that: when the optimized arrangement was used, the stress state of the high-strength bolts connections has a little change, but 19%~25%bolts can be saved. 3 tabs, 10 figs, 11 refs.

  20. Matching nuts and bolts in O(n log n) time

    Energy Technology Data Exchange (ETDEWEB)

    Komlos, J. [Rutgers Univ., Piscataway, NJ (United States); Ma, Yuan [Stanford Univ., CA (United States); Szemeredi, E. [Rutgers Univ., Piscataway, NJ (United States)

    1996-12-31

    Given a set of n nuts of distinct widths and a set of n bolts such that each nut corresponds to a unique bolt of the same width, how should we match every nut with its corresponding bolt by comparing nuts with bolts (no comparison is allowed between two nuts or between two bolts)? The problem can be naturally viewed as a variant of the classic sorting problem as follows. Given two lists of n numbers each such that one list is a permutation of the other, how should we sort the lists by comparisons only between numbers in different lists? We give an O(n log n)-time deterministic algorithm for the problem. This is optimal up to a constant factor and answers an open question posed by Alon, Blum, Fiat, Kannan, Naor, and Ostrovsky. Moreover, when copies of nuts and bolts are allowed, our algorithm runs in optimal O(log n) time on n processors in Valiant`s parallel comparison tree model. Our algorithm is based on the AKS sorting algorithm with substantial modifications.

  1. FEM analyses of stress and deformation of a flexible inner pressure bolt

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhong-he; WANG Wei-qiang; ZHANG Le-wen

    2008-01-01

    The flexible inner pressure bolt is a new kind and new structural bolt (anchor rod). A number of structural improvements and performance test have been carried out. The bolt has superior compatibility to the soft crag and the large distortion tunnel with its flexibility. In order to study its stress, deformation and interaction mechanism thoroughly, a number of large distortion calculations and analyses have been carried out on the bolt by FEM (finite element method), especially with the ANSYS software, based on the updated Lagrangian law. The results show that the maximum stress of the inner wall of the bolt is consistent with an elastic analytic solution. The maximum stress on the body occurs in the vicinity of the enhancement material. The link enhancement of the body seems to be quite essential. The experimental results indicate that the maximum injection pressure in the bolt is 2.5 MPa without link enhancement and 8.3 MPa with the enhancement. This link enhancement effect is highly significant. These results provide some basis for the design, application and anchoring stress analysis of the holt.

  2. Study on Mechanical Characteristics of Fully Grouted Rock Bolts for Underground Caverns under Seismic Loads

    Directory of Open Access Journals (Sweden)

    Guoqing Liu

    2017-01-01

    Full Text Available This study establishes an analytical model for the interaction between the bolt and surrounding rock based on the bearing mechanism of fully grouted rock bolts. The corresponding controlled differential equation for load transfer is deduced. The stress distributions of the anchorage body are obtained by solving the equations. A dynamic algorithm for the bolt considering shear damage on the anchoring interface is proposed based on the dynamic finite element method. The rationality of the algorithm is verified by a pull-out test and excavation simulation of a rounded tunnel. Then, a case study on the mechanical characteristics of the bolts in underground caverns under seismic loads is conducted. The results indicate that the seismic load may lead to stress originating from the bolts and damage on the anchoring interface. The key positions of the antiseismic support can be determined using the numerical simulation. The calculated results can serve as a reference for the antiseismic optimal design of bolts in underground caverns.

  3. Experimental studies on the effects of bolt parameters on the bearing characteristics of reinforced rock.

    Science.gov (United States)

    Cheng, Liang; Zhang, Yidong; Ji, Ming; Zhang, Kai; Zhang, Minglei

    2016-01-01

    Roadways supported by bolts contain support structures that are built into the rock surrounding the roadway, referred to as reinforced rocks in this paper. Using physical model simulation, the paper investigates the bearing characteristics of the reinforced rock under different bolt parameters with incrementally increased load. The experimental results show that the stress at the measurement point inside the structure varies with the kinetic pressure. The stress increases slowly as the load is initially applied, displays accelerated growth in the middle of the loading application, and decreases or remains constant in the later stage of the loading application. The change in displacement of the surrounding rock exhibits the following characteristics: a slow increase when the load is first applied, accelerated growth in the middle stage, and violent growth in the later stage. There is a good correlation between the change in the measured stress and the change in the surrounding rock displacement. Increasing the density of the bolt support and the length and diameter of the bolt improves the load-bearing performance of the reinforced rock, including its strength, internal peak stress, and residual stress. Bolting improves the internal structure of the surrounding rocks, and the deterioration of the surrounding rock decreases with the distance between the bolt supports.

  4. Failure Characteristics of Joint Bolts in Shield Tunnels Subjected to Impact Loads from a Derailed Train

    Directory of Open Access Journals (Sweden)

    Qixiang Yan

    2017-01-01

    Full Text Available Impact loads generated by derailed trains can be extremely high, especially in the case of heavy trains running at high speeds, which usually cause significant safety issues to the rail infrastructures. In shield tunnels, such impact loads may not only cause the damage and deformation of concrete segments, but also lead to the failure of segmental joint bolts. This paper presents a numerical study on the failure behavior of segmental joint bolts in the shield tunnel under impact loading resulting from train derailments. A three-dimensional (3D numerical model of a shield tunnel based on the finite element (FE modelling strategy was established, in which the structural behavior of the segmental joint surfaces and the mechanical behavior of the segmental joint bolts were determined. The numerical results show that the occurrence of bolt failure starts at the joints near the impacted segment and develops along the travel direction of train. An extensive parametric study was subsequently performed and the influences of the bolt failure on the dynamic response of the segment were investigated. In particular, the proposed FE model and the analytical results will be used for optimizing the design method of the shield tunnel in preventing the failure of the joint bolts due to the impact load from a derailed HST.

  5. Development of an FPGA-based multipoint laser pyroshock measurement system for explosive bolts.

    Science.gov (United States)

    Abbas, Syed Haider; Jang, Jae-Kyeong; Lee, Jung-Ryul; Kim, Zaeill

    2016-07-01

    Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure. This paper presents a technology to measure a pyroshock wave at multiple points using laser Doppler vibrometers (LDVs). These LDVs detect the pyroshock wave generated due to an explosive-based pyrotechnical event. Field programmable gate array (FPGA) based data acquisition is used in the study to acquire pyroshock signals simultaneously from multiple channels. This paper describes the complete system design for multipoint pyroshock measurement. The firmware architecture for the implementation of multichannel data acquisition on an FPGA-based development board is also discussed. An experiment using explosive bolts was configured to test the reliability of the system. Pyroshock was generated using explosive excitation on a 22-mm-thick steel plate. Three LDVs were deployed to capture the pyroshock wave at different points. The pyroshocks captured were displayed as acceleration plots. The results showed that our system effectively captured the pyroshock wave with a peak-to-peak magnitude of 303 741 g. The contribution of this paper is a specialized architecture of firmware design programmed in FPGA for data acquisition of large amount of multichannel pyroshock data. The advantages of the developed system are the near-field, multipoint, non-contact, and remote measurement of a pyroshock wave, which is dangerous and expensive to produce in aerospace pyrotechnic tests.

  6. Development of an FPGA-based multipoint laser pyroshock measurement system for explosive bolts

    Science.gov (United States)

    Abbas, Syed Haider; Jang, Jae-Kyeong; Lee, Jung-Ryul; Kim, Zaeill

    2016-07-01

    Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure. This paper presents a technology to measure a pyroshock wave at multiple points using laser Doppler vibrometers (LDVs). These LDVs detect the pyroshock wave generated due to an explosive-based pyrotechnical event. Field programmable gate array (FPGA) based data acquisition is used in the study to acquire pyroshock signals simultaneously from multiple channels. This paper describes the complete system design for multipoint pyroshock measurement. The firmware architecture for the implementation of multichannel data acquisition on an FPGA-based development board is also discussed. An experiment using explosive bolts was configured to test the reliability of the system. Pyroshock was generated using explosive excitation on a 22-mm-thick steel plate. Three LDVs were deployed to capture the pyroshock wave at different points. The pyroshocks captured were displayed as acceleration plots. The results showed that our system effectively captured the pyroshock wave with a peak-to-peak magnitude of 303 741 g. The contribution of this paper is a specialized architecture of firmware design programmed in FPGA for data acquisition of large amount of multichannel pyroshock data. The advantages of the developed system are the near-field, multipoint, non-contact, and remote measurement of a pyroshock wave, which is dangerous and expensive to produce in aerospace pyrotechnic tests.

  7. Crossroads - Bridging the Digital Divide

    Directory of Open Access Journals (Sweden)

    David Cobb

    2005-03-01

    Full Text Available It’s so good to be in Cambridge, it feels almost like home. Let me start by stating that in the past year ITMB, a successful map publisher in British Columbia, Canada published more paper map titles than at any time in their history. Similarly, the U.S. Geological Survey (USGS recently announced that they have ceased producing paper from their aerial photography archive and will only produce digital copies. I believe that both of these facts speak to the future of maps and digital data. It means there will be paper maps well into the future and there will be an increasing array of digital data - some of it reformatted, as in the USGS case, and most of it will be born digital. When asked to speak about GIS and its role in libraries I often find myself in a conundrum - am I here to slay the dragon, or to pet the dragon. The role of technology in libraries is not one that has been embraced by everyone, and often the technology itself seems to have been force-fed upon us. The library profession is not one that has historically been a proponent of change and the very nature of GIS is change. In one sense, we have been given the choice of becoming paper museums or, at the very least, making GIS technology available in our collections. Today, I would like to review the many ways that GIS is, or will, affect our collections. I will divide the presentation into a general overview of GIS in libraries, how it affects our acquisitions or collection development policies, its effect on cataloging, on reference services, staffing, and our web services. Then I will shift the focus a little and discuss the current situation at the Harvard Map Collection, the future role of legacy collections, and a look to the future.

  8. Improving boiler foundation bolt installation technology%提高锅炉地脚螺栓安装工艺

    Institute of Scientific and Technical Information of China (English)

    李晓峰

    2014-01-01

    阐述了锅炉地脚螺栓安装前的准备工作,通过对螺栓安装施工工艺流程的介绍,分析了提高螺栓与螺栓支架安装精度的方法,并对检验螺栓安装质量的技术要点作了研究,以确保锅炉地脚螺栓安装的正确无误。%The paper illustrates boiler foundation bolt installation preparations. Through introducing bolt installation technology procedures, it analyzes methods of improving bolt and bolt support installation accuracy, and studies technological points of examining bolt installation quality, with a view to guarantee boiler foundation bolt installation correct.

  9. Analysis of Yielding Steel Arch Support with Rock Bolts in Mine Roadways Stability Aspect

    Science.gov (United States)

    Majcherczyk, Tadeusz; Niedbalski, Zbigniew; Małkowski, Piotr; Bednarek, łukasz

    2014-10-01

    The result of the search for new technological solutions in the field of support for roadways in coal mines has in recent years been the widespread use of steel arch with rockbolt support systems. The efficiency of these systems is affected among other things by the option of installing rock bolts after the actual driving the mine roadway, the increased load capacity that these systems can support, and their resistance to dynamic weight. Large variation in the way that these steel arch support can be connected using different types of rock bolts necessitates mining research revealing the effectiveness of such solutions. Although the steel arch with rockbolt support system is used in the majority of European coal mines, it is still not possible to apply templates of schemes due to the diversity of geological and mining conditions. Therefore, throughout a period of several years, the authors of this article conducted research in situ under conditions of different schemes related to connecting arched support frames with rock bolts, with only selected results being presented in the article. The measurements of convergence, load supported by the system frame, load supported by the rock bolts, and the stratification of roof rocks were analyzed, carried out in two roadways with yielding steel arch support in which strand bolts were applied. The article also proposes the index for working maintenance nuw, used in preliminarily assessing the stability of a given working with a limited number of data concerning geomechanical conditions. Additionally considered are empirical methods used in Poland for designing steel arch with rock bolt support systems. The results of mine research indicate that strengthening yielding steel support with strand bolts through steel beams maintains the stability of a roadway, even when exposed to the exploitation stress. Aside from the impact of exploitation, deformations of the support system are negligible, despite the fact that the tensile

  10. A Component-Based Study of the Effect of Diameter on Bond and Anchorage Characteristics of Blind-Bolted Connections.

    Directory of Open Access Journals (Sweden)

    Muhammad Nasir Amin

    Full Text Available Structural hollow sections are gaining worldwide importance due to their structural and architectural advantages over open steel sections. The only obstacle to their use is their connection with other structural members. To overcome the obstacle of tightening the bolt from one side has given birth to the concept of blind bolts. Blind bolts, being the practical solution to the connection hindrance for the use of hollow and concrete filled hollow sections play a vital role. Flowdrill, the Huck High Strength Blind Bolt and the Lindapter Hollobolt are the well-known commercially available blind bolts. Although the development of blind bolts has largely resolved this issue, the use of structural hollow sections remains limited to shear resistance. Therefore, a new modified version of the blind bolt, known as the "Extended Hollo-Bolt" (EHB due to its enhanced capacity for bonding with concrete, can overcome the issue of low moment resistance capacity associated with blind-bolted connections. The load transfer mechanism of this recently developed blind bolt remains unclear, however. This study uses a parametric approach to characterising the EHB, using diameter as the variable parameter. Stiffness and load-carrying capacity were evaluated at two different bolt sizes. To investigate the load transfer mechanism, a component-based study of the bond and anchorage characteristics was performed by breaking down the EHB into its components. The results of the study provide insight into the load transfer mechanism of the blind bolt in question. The proposed component-based model was validated by a spring model, through which the stiffness of the EHB was compared to that of its components combined. The combined stiffness of the components was found to be roughly equivalent to that of the EHB as a whole, validating the use of this component-based approach.

  11. Forces in bolted joints: analysis methods and test results utilized for nuclear core applications (LWBR Development Program)

    Energy Technology Data Exchange (ETDEWEB)

    Crescimanno, P.J.; Keller, K.L.

    1981-03-01

    Analytical methods and test data employed in the core design of bolted joints for the LWBR core are presented. The effects of external working loads, thermal expansion, and material stress relaxation are considered in the formulation developed to analyze joint performance. Extensions of these methods are also provided for bolted joints having both axial and bending flexibilities, and for the effect of plastic deformation on internal forces developed in a bolted joint. Design applications are illustrated by examples.

  12. European development Rock bolting. Desarrollo Europeo del Bulonaje

    Energy Technology Data Exchange (ETDEWEB)

    1999-01-01

    The project European Development Rockbolting which was developed during the period 1994-1997 and carried out within the OCICARBON Action Program (OCICARBON-ITGE agreement dated September 1, 1994, Code C-13-438) as well as within the framework of the Coal Technical research Program of the D. G. XVII of the EEC, n 7220/AB/143. The project has had the following external partners: DMT (Germany), BCC (UK) and CDF (France), and the collaboration of INERIS (France), RMT (UK) and GEOCONTROL S. A. (Spain). The objective of the investigation was to improve the techniques and design currently used in the application of rockbolts for supporting of both infrastructure and beds in the European coal mining. The most important result, besides that derived from the sharing of experiences and knowledge, was the technological design of a supporting system, which was carried out by each partner for the various proposed exploitations. The Spanish part carried out the works of designing and estimation of the bolting system corresponding to the exploitations of: -Carbones de Pedraforca SA. Saldes mine. -U. E. Provence. Pit Y. Morandat.

  13. European development Rock bolting; Desarrollo Europeo del Bulonaje

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    The project European Development Rockbolting which was developed during the period 1994-1997 and carried out within the OCICARBON Action Program (OCICARBON-ITGE agreement dated September 1, 1994, Code C-13-438) as well as within the framework of the Coal Technical research Program of the D. G. XVII of the EEC, n 7220/AB/143. The project has had the following external partners: DMT (Germany), BCC (UK) and CDF (France), and the collaboration of INERIS (France), RMT (UK) and GEOCONTROL S. A. (Spain). The objective of the investigation was to improve the techniques and design currently used in the application of rockbolts for supporting of both infrastructure and beds in the European coal mining. The most important result, besides that derived from the sharing of experiences and knowledge, was the technological design of a supporting system, which was carried out by each partner for the various proposed exploitations. The Spanish part carried out the works of designing and estimation of the bolting system corresponding to the exploitations of: -Carbones de Pedraforca SA. Saldes mine. -U. E. Provence. Pit Y. Morandat.

  14. FE-MODELLING OF A CONTACT LAYER BETWEEN ELEMENTS JOINED IN PRELOADED BOLTED CONNECTIONS FOR THE OPERATIONAL CONDITION

    Directory of Open Access Journals (Sweden)

    Rafał Grzejda

    2014-11-01

    Full Text Available Modelling and calculations of a contact layer between elements joined in a preloaded bolted connection for the operational condition are presented. The physical model of the bolted connection is based on a flexible flange element that is joined with a rigid support by means of the no-bolt model (at the assembly stage or the rigid body bolt model (at the operational stage. The contact layer between joined elements is described as the nonlinear Winkler model. The contact joint model considering an experimental normal elastic characteristic is presented. Examples of normal contact pressure and normal contact deformations distributions are contained.

  15. A Method to Capture Macroslip at Bolted Interfaces [PowerPoint

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, Ronald Neil; Heitman, Lili Anne Akin

    2016-01-01

    Relative motion at bolted connections can occur for large shock loads as the internal shear force in the bolted connection overcomes the frictional resistive force. This macroslip in a structure dissipates energy and reduces the response of the components above the bolted connection. There is a need to be able to capture macroslip behavior in a structural dynamics model. A linear model and many nonlinear models are not able to predict marcoslip effectively. The proposed method to capture macroslip is to use the multi-body dynamics code ADAMS to model joints with 3-D contact at the bolted interfaces. This model includes both static and dynamic friction. The joints are preloaded and the pinning effect when a bolt shank impacts a through hole inside diameter is captured. Substructure representations of the components are included to account for component flexibility and dynamics. This method was applied to a simplified model of an aerospace structure and validation experiments were performed to test the adequacy of the method.

  16. Corrosion monitoring of rock bolt by using a low coherent fiber-optic interferometry

    Science.gov (United States)

    Wei, Heming; Zhao, Xuefeng; Li, Dongsheng; Zhang, Pinglei; Sun, Changsen

    2015-04-01

    Corrosion of rock bolts is a major cause for deterioration of the anchor-reinforced concrete slopes structures. In order to evaluate this corrosion-based deterioration in an early stage, a nondestructive technique was required. However, until now, there are no commercialized solutions that are straightforwardly available. Here, a low-coherent fiber-optic sensing technique was developed. This method can carry out the monitoring of the corrosion-caused expansion at the accuracy of sub-microstrains by circled the sensing optical fiber in two ways. One was wound the fiber on the surface of steel rock bolt directly, and thereby generated a nonuniformity in the interface of cement with rock bolt. The other was circled the fiber on a cement mortar cushion without destroying the interface any way. The sensing fiber was configured as one arm of the fiber-optic Michelson interferometer. The acceleration corrosion experiments demonstrated that a uniform interface between cement and rock bolt determined the progress of corrosion development. An early stage evaluation of the corrosion development in rock bolts was monitored.

  17. Submillimeter bolt location in car bodywork for production line quality inspection

    Science.gov (United States)

    Altamirano-Robles, Leopoldo; Arias-Estrada, Miguel; Alviso-Quibrera, Samuel; Lopez-Lopez, Aurelio

    2000-03-01

    In the automotive industry, a vehicle begins with the construction of the vehicle floor. Later on, several robots weld a series of bolts to this floor which are used to fix other parts. Due to several problems, like welding tools wearing, robot miscalibration or momentary low power supply, among others, some bolts are incorrectly positioned or are not present at all, bringing problems and delays in the next work cells. Therefore, it is of importance to verify the quality of welded parts before the following assembly steps. A computer vision system is proposed in order to locate autonomously the presence and quality of the bolts. The system should carry on the inspection in real time at the car assembly line under the following conditions: without touching the bodywork, with a precision in the submillimeter range and in few seconds. In this paper we present a basic computer vision system for bolt location in the submillimeter range. We analyze three arrangements of the system components (camera and illumination sources) that produce different results in the localization. Results are presented and compared for the three approaches obtained under laboratory conditions. The algorithms were tested in the assembling line. Variations up to one millimeter in the welded position of the bolts were observed.

  18. Parameter analysis of anchor bolt support for large-span and jointed rock mass

    Institute of Scientific and Technical Information of China (English)

    LI Xi-bing; ZHOU Zi-long; LI Qi-yue; HU Liu-qing

    2005-01-01

    In order to obtain the optimal parameters of anchor bolt supporting system for large-span and jointed rock mass in Kaiyang Phosphor Mine, it is expensive and unavailable with the method of in-situ experiments. This paper describes a numerical modeling with discrete element method for the supporting effects of different type of anchor bolts. The anchor bolts with variant length of 0.5 m, 0.8 m, 1.0 m, diameter of 10 mm, 15 mm, 20 mm, setting spacing of 3.0 m, 2.5 m, 2.0 m, and setting angle of 10°, 20°, 30°, are simulated respectively. The results show that there exist optimal parameters of anchor bolt support for large-span and jointed rock mass. For the bolt support of the concerning, the optimal length is 2.5-3.5 m, the diameter is 25-35 mm, the spacing is 0.5-0.6 m, and the setting angle is 105°.

  19. Some results on numerical divided difference formulas

    Institute of Scientific and Technical Information of China (English)

    Wang; Xinghua; Wang; Heyu; Ming-Jun; Lai

    2005-01-01

    The remainder estimates of numerical divided difference formula are given for the functions of lower and higher smoothness, respectively. Then several divided difference formulas with super-convergence are derived with their remainder expressions.

  20. Tech, Teachers & Teens: Bridging the Divide

    Science.gov (United States)

    Stuht, Amy Colcord; Colcord, Cean

    2011-01-01

    In past decades, the "digital divide" referred to the gap between those who could afford access to technology and those who could not. The divide has shifted in recent years to reflect the growing technological chasm between teachers and their students: today's schools and teenagers' worlds. The digital divide is widening and deepening…

  1. The Myth about the Digital Divide

    Science.gov (United States)

    Hawkins, Brian L.; Oblinge, Diana G.

    2006-01-01

    Although computer ownership is not 100 percent, progress has been made on closing the digital divide. However, defining the digital divide according to the haves and have-nots of computer ownership is only a starting point. Beyond computer ownership, colleges and universities should explore the "second-level digital divide," which can be…

  2. Diversity, Disability, and Geographic Digital Divide

    Science.gov (United States)

    Sumari, Melati; Carr, Erika; Ndebe-Ngovo, Manjerngie

    2006-01-01

    The phenomenon called digital divide was the focus of this paper. Diversity, disability, and geographical digital divide were relevant to this collaborative project. An extensive review of the literature was conducted for the completion of this project. The evidence for the digital divide in terms of race, level of education, and gender in the…

  3. A Redox-Mediated Modulation of Stem Bolting in Transgenic Nicotiana sylvestris Differentially Expressing the External Mitochondrial NADPH Dehydrogenase1[W][OA

    National Research Council Canada - National Science Library

    Yun-Jun Liu; Adriano Nunes-Nesi; Sabá V Wallström; Ida Lager; Agnieszka M Michalecka; Fredrik E B Norberg; Susanne Widell; Kenneth M Fredlund; Alisdair R Fernie; Allan G Rasmusson

    2009-01-01

    .... Nicotiana sylvestris plants overexpressing potato (Solanum tuberosum) NDB1 displayed early bolting, whereas sense suppression of the same gene led to delayed bolting, with consequential changes in flowering time...

  4. 大直径铝合金铆钉以铆代螺可行性试验研究%Experimental Investigation on Feasibility of Substituting Large Diameter Riveting for Bolting

    Institute of Scientific and Technical Information of China (English)

    于海平; 张旭; 章茂云; 孙立强; 李春峰

    2016-01-01

    The EMR experiments were performed on bi-layer aluminum alloy plates withΦ10mm 2A10 aluminum alloy rivets. The microstructure of EMR joints were observed, mechanical properties were tested and compared with those of bolting joint with steel bolt. The results show that an increasing discharge voltage enhances dimensions of rivet head. The rivet head is characterized with adiabatic shear deformation. Maximum shear and pull off load of the rivet joints are respectively 23.3kN and 35.0kN, which are higher than those of bolting joint. And the weight loss of EMR joint is up to 15.8%in contrast to bolting one.%针对双层铝合金板铆接结构,通过电磁铆接工艺试验,分析Φ10mm-2A10铝合金铆钉镦头的微观组织,与钢质螺栓连接接头对比评价了铆接接头的力学性能。研究发现,随放电电压的增加,铆钉镦头直径逐渐增加、高度逐渐降低。铆钉镦头以绝热剪切为主要变形模式。铆接接头的最大剪切和拉脱载荷分别为23.3kN和35.0kN,均高于钢质螺栓连接接头,并且相对于螺接接头可减重15.8%。

  5. Numerical Computation of Stress Intensity Factors for Bolt-hole Corner Crack in Mechanical Joints

    Institute of Scientific and Technical Information of China (English)

    Wang Liqing; Gai Bingzheng

    2008-01-01

    The three-dimensional finite element method is used to solve the problem of the quarter-elliptical comer crack of the bolt-hole in mechanical joints being subjected to remote tension. The square-root stress singularity around the corner crack front is simulated using the collapsed 20-node quarter point singular elements. The contact interaction between the bolt and the hole boundary is considered in the finite element analysis. The stress intensity factors (SIFs) along the crack front are evaluated by using the displacement correlation technique. The effects of the amount of clearance between the hole and the bolt on the SIFs are investigated. The numerical results indicate that the SIF for mode I decrease with the decreases in clearance, and in the cases of clearance being present, the corner crack is in a mix-mode, even if mode I loading is dominant.

  6. Review Paper on Performance Evaluation of Nut and Bolt Recognition System Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Shruti Paunikar

    2013-09-01

    Full Text Available There is constant research going on in the field of recognition by means of artificial intelligence to enhance the productivity. The automotive industry requires an automated system to sort different sizes and shapes nut and bolt which are the mainly used component in the industry, to improve the overall productivity. This review paper deals with some feature extraction techniques and its performance impact on the artificial neural network efficiency for the recognition of nut and bolt. The main feature extraction techniques analysed for this review paper are stationary wavelet transform, principle component analysis and radius analysis. The aforementioned techniques are already tested and simulation is done on MATLAB.The results obtained varies depending on pre-processing techniques used for the nut and bolt recognition.

  7. Simulation and experiment for the inspection of stainless steel bolts in servicing using an ultrasonic phased array

    Science.gov (United States)

    Chen, Jinzhong; He, Renyang; Kang, Xiaowei; Yang, Xuyun

    2015-10-01

    The non-destructive testing of small-sized (M12-M20) stainless steel bolts in servicing is always a technical problem. This article focuses on the simulation and experimental research of stainless steel bolts with an artificial defect reflector using ultrasonic phased array inspection. Based on the observation of the sound field distribution of stainless steel bolts in ultrasonic phased array as well as simulation modelling and analysis of the phased array probes' detection effects with various defect sizes, different artificial defect reflectors of M16 stainless steel bolts are machined in reference to the simulation results. Next, those bolts are tested using a 10-wafer phased array probe with 5 MHz. The test results finally prove that ultrasonic phased array can detect 1-mm cracks in diameter with different depths of M16 stainless steel bolts and a metal loss of Φ1 mm of through-hole bolts, which provides technical support for future non-destructive testing of stainless steel bolts in servicing.

  8. The Analysis of the Water-Expanded Rock Bolts Ruptures During Pressure Test

    Science.gov (United States)

    Pawłowski, Bogdan; Krawczyk, Janusz; Bała, Piotr; Cios, Grzegorz; Tokarski, Tomasz

    2017-06-01

    This paper describe the investigation of a water-expanded rock bolts failed during pressure test (inner water pressure of 330 bar). A main objective of this work was to determine the cracks nucleation and propagation mechanism. It was found that the rock bolts failure was promoted by presence of non-metallic inclusions (mainly long sulphide inclusions) but the primary cause of cracking is strain ageing of steel. Suggestions for improving the behaviour of steel used for water-expanded rock belts by the modification of its chemical composition are proposed finally.

  9. The Effect of Temperature on Bearing Strength of CFRP Bolted Joint with Washer Constraining

    OpenAIRE

    Hirano, Noriyoshi; Wang, Wen-Xue; Takao, Yoshihiro

    2012-01-01

    Effects of temperature on the bearing strength of a CF/Epoxy quasi-isotropic laminate bolted joint are investigated experimentally. The material system is CF/Epoxy T800H/#3631 with stacking sequence of [0/45/-45/90]_. In this study, a semi-circular notched specimen is chosen and loaded in compression instead of a well-known double lap joint. This method has advantages in material cost and simplicity of its damage mode. A bolted joint with the washer constraint is loaded at 25, 150 and —100℃. ...

  10. Create Your Plate

    Medline Plus

    Full Text Available ... A A A Listen En Español Create Your Plate Create Your Plate is a simple and effective ... and that your options are endless. Create Your Plate! Click on the plate sections below to add ...

  11. Fast frequency divider circuit using combinational logic

    Science.gov (United States)

    Helinski, Ryan

    2017-05-30

    The various technologies presented herein relate to performing on-chip frequency division of an operating frequency of a ring oscillator (RO). Per the various embodiments herein, a conflict between RO size versus operational frequency can be addressed by dividing the output frequency of the RO to a frequency that can be measured on-chip. A frequency divider circuit (comprising NOR gates and latches, for example) can be utilized in conjunction with the RO on the chip. In an embodiment, the frequency divider circuit can include a pair of latches coupled to the RO to facilitate dividing the oscillating frequency of the RO by 2. In another embodiment, the frequency divider circuit can include four latches (operating in pairs) coupled to the RO to facilitate dividing the oscillating frequency of the RO by 4. A plurality of ROs can be MUXed to the plurality of ROs by a single oscillation-counting circuit.

  12. Inductive voltage divider modeling in Matlab

    Science.gov (United States)

    Andreev, S. A.; Kim, V. L.

    2017-01-01

    Inductive voltage dividers have the most appropriate metrological characteristics on alternative current and are widely used for converting physical signals. The model of a double-decade inductive voltage divider was designed with the help of Matlab/Simulink. The first decade is an inductive voltage divider with balanced winding, the second decade is a single-stage inductive voltage divider. In the paper, a new transfer function algorithm was given. The study shows errors and differences that appeared between the third degree reduced model and a twenty degree unreduced model. The obtained results of amplitude error differ no more than by 7 % between the reduced and unreduced model.

  13. A model updating method for hybrid composite/aluminum bolted joints using modal test data

    Science.gov (United States)

    Adel, Farhad; Shokrollahi, Saeed; Jamal-Omidi, Majid; Ahmadian, Hamid

    2017-05-01

    The aim of this paper is to present a simple and applicable model for predicting the dynamic behavior of bolted joints in hybrid aluminum/composite structures and its model updating using modal test data. In this regards, after investigations on bolted joints in metallic structures which led to a new concept called joint affected region (JAR) published in Shokrollahi and Adel (2016), now, a doubly connective layer is established in order to simulate the bolted joint interfaces in hybrid structures. Using the proposed model, the natural frequencies of the hybrid bolted joint structure are computed and compared to the modal test results in order to evaluate and verify the new model predictions. Because of differences in the results of two approaches, the finite element (FE) model is updated based on the genetic algorithm (GA) by minimizing the differences between analytical model and test results. This is done by identifying the parameters at the JAR including isotropic Young's modulus in metallic substructure and that of anisotropic composite substructure. The updated model compared to the initial model simulates experimental results more properly. Therefore, the proposed model can be used for modal analysis of the hybrid joint interfaces in complex and large structures.

  14. Fewer complications with bolt-connected than tunneled external ventricular drainage

    DEFF Research Database (Denmark)

    Jensen, Torben Slott; Carlsen, Jakob Gram; Sørensen, Jens Christian;

    2016-01-01

    BACKGROUND: Ventriculostomy/external ventricular drain (EVD) is a common neurosurgical procedure. Various techniques are used to fixate the drain and the objective of this study was, in a retrospective setting, to compare the incidence of complications when using bolt-connected EVD (BC-EVD) versus...

  15. Evaluation of Many Load Tests of Passive Rock Bolts in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Holý Ondřej

    2017-03-01

    Full Text Available Within the research project “FR-TI4/329 Research and development - creating an application system for the design and analysis of soil and rock anchors including the development of monitoring elements”, an extensive stage of field load tests of rock bolts was carried out. The tests were conducted at 14 locations with varied rock composition. Before the initial tests, a loading stand was designed and constructed. A total of 201 pieces of tensile tests of bolts having lengths from 0.5 up to 2.5 m, a diameter of 22-32 mm, were performed. These were fully threaded rods, self-drilling rods, and fiberglass rods. The bolts were clamped into the cement and resin. The loading tests were always performed until material failure of bolts or shear stress failure at the interface cement-rock. At each location, basic geotechnical survey was carried out in the form of core drilling in a length of 3.0 metres with the assessment of the rock mass in situ, and laboratory testing of rock mechanics. Upon the completion of testing protocols, rock mass properties analysis was performed focusing on the evaluation of shear friction at the grouting-rock interface.

  16. Loosening and Sliding Behaviour of Bolt-Nut Fastener under Transverse Loading

    Directory of Open Access Journals (Sweden)

    Naruse T.

    2010-06-01

    Full Text Available The thread joint has been frequently used for the efficient productivity and maintainability as a machine element. However, many troubles such as loosening of bolted joints or fatigue failure of bolt were often experienced. Many attentions must be paid on the improvement of the strength and the reliability of the thread joints [1, 2]. It is generally said that the fastening axial force rapidly decreases by the rotation loosening of nuts if the relative slippage on the interfaces between nuts and fastened body goes beyond a certain critical limit [3]. This critical relative slippage (Scr that prescribes the upper limit for preventing the loosening behaviour has been estimated according to the theoretically obtained equation considering the bending deformation of bolt and the geometrical constraint condition. In this paper, firstly we present the equation for estimating the Scr based on the fundamental cantilever deformation model. Then we present the investigated results of the deformation behaviour of bolt-nut joint under transverse loading condition considering the reaction moment by nut (Mn. Finaly we can confirmed that these estimated results of critical relative slippage coincided well with the experimental results [4, 5].

  17. Beware of Nuts and Bolts: Putting Evolution into the Teaching of Biological Classification

    Science.gov (United States)

    Nickels, Martin K.; Nelson, Craig E.

    2005-01-01

    Biological classification embodies the most fundamental idea in all of biology, especially evolution. The contrast between biological classifications and those of manufactured objects for instance hardware-based collection of screws, nails and bolts, help illustrate the central biological ideas and induce student interest, however, this could be…

  18. Secondary skull fractures in head wounds inflicted by captive bolt guns: autopsy findings and experimental simulation.

    Science.gov (United States)

    Perdekamp, Markus Grosse; Kneubuehl, Beat P; Ishikawa, Takaki; Nadjem, Hadi; Kromeier, Jan; Pollak, Stefan; Thierauf, Annette

    2010-11-01

    Apart from one article published by Rabl and Sigrist in 1992 (Rechtsmedizin 2:156-158), there are no further reports on secondary skull fractures in shots from captive bolt guns. Up to now, the pertinent literature places particular emphasis on the absence of indirect lesions away from the impact point, when dealing with the wounding capacity of slaughterer's guns. The recent observation of two suicidal head injuries accompanied by skull fractures far away from the bolt's path gave occasion to experimental studies using simulants (glycerin soap, balls from gelatin) and skull–brain models. As far as ballistic soap was concerned, the dimensions of the bolt's channel were assessed by multi-slice computed tomography before cutting the blocks open. The test shots to gelatin balls and to skull-brain models were documented by means of a high-speed motion camera. As expected, the typical temporary cavity effect of bullets fired from conventional guns could not be observed when captive bolt stunners were discharged. Nevertheless, the visualized transfer of kinetic energy justifies the assumption that the secondary fractures seen in thin parts of the skull were caused by a hydraulic burst effect.

  19. Velocity dispersions in a cluster of stars: How fast could Usain Bolt have run?

    CERN Document Server

    Eriksen, H K; Langangen, O; Wehus, I K

    2008-01-01

    Since that very memorable day at the Beijing 2008 Olympics, a big question on every sports commentator's mind has been "What would the 100 meter dash world record have been, had Usain Bolt not celebrated at the end of his race?" Glen Mills, Bolt's coach suggested at a recent press conference that the time could have been 9.52 seconds or better. We revisit this question by measuring Bolt's position as a function of time using footage of the run, and then extrapolate into the last two seconds based on two different assumptions. First, we conservatively assume that Bolt could have maintained Richard Thompson's, the runner-up, acceleration during the end of the race. Second, based on the race development prior to the celebration, we assume that he could also have kept an acceleration of 0.5 m/s^2 higher than Thompson. In these two cases, we find that the new world record would have been 9.61 +/- 0.04 and 9.55 +/- 0.04 seconds, respectively, where the uncertainties denote 95% statistical errors.

  20. Bridge the Digital Divide for Educational Equity

    Science.gov (United States)

    Mason, Christine Y.; Dodds, Richard

    2005-01-01

    Students' technological savvy has challenged schools to make greater use of computers and the Internet in their curricula, but unfortunately, not every student has the same access to it, and the inability to keep pace has created a digital divide that continues to widen. The digital divide particularly affects students who are black, Hispanic,…

  1. Social Welfare Implications of the Digital Divide

    Science.gov (United States)

    Kim, Eunjin; Lee, Byungtae; Menon, Nirup M.

    2009-01-01

    The Internet plays a critical role in informing individuals about society, politics, business, and the environment. So much so that it has been said that the digital divide makes the segment of society on the ''right side'' of the divide (the digitally endowed group) better off and that on the ''wrong side'' (the digitally challenged group) worse…

  2. New Media and the Digital Divide

    NARCIS (Netherlands)

    Deursen, van A.J.A.M.; Dijk, van J.A.G.M.; Wright, James D.

    2015-01-01

    During the 1990s, researchers and policy makers began discussing the presence of a so-called ‘digital divide,’ a distinction of people who do and do not have access to information and communication technologies. The concept of the digital divide stems from a comparative perspective of social and inf

  3. A Smart Washer for Bolt Looseness Monitoring Based on Piezoelectric Active Sensing Method

    Directory of Open Access Journals (Sweden)

    Heyue Yin

    2016-10-01

    Full Text Available Piezoceramic based active sensing methods have been researched to monitor preload on bolt connections. However, there is a saturation problem involved with this type of method. The transmitted energy is sometimes saturated before the maximum preload which is due to it coming into contact with flat surfaces. When it comes to flat contact surfaces, the true contact area will easily saturate with the preload. The design of a new type of bolt looseness monitoring sensor, a smart washer, is to mitigate the saturation problem. The smart washer is composed of two annular disks with contact surfaces that are machined into convex and concave respectively, to eliminate the complete flat contact surfaces and to reduce the saturation effect. One piezoelectric patch is bonded on the non-contact surface of each annular disk. These two mating annular disks form a smart washer. One of the two piezoelectric patches serves as an actuator to generate an ultrasonic wave that propagates through the contact surface; the other one serves as a sensor to detect the propagated waves. The wave energy propagated through the contact surface is proportional to the true contact area which is determined by the bolt preload. The time reversal method is used to extract the peak of the focused signal as the index of the transmission wave energy; then, the relationship between the signal peak and bolt preload is obtained. Experimental results show that the focused signal peak value changes with the bolt preload and presents an approximate linear relationship when the saturation problem is experienced. The proposed smart washer can monitor the full range of the rated preload.

  4. Linkage Map Construction and Quantitative Trait Loci Analysis for Bolting Based on a Double Haploid Population of Brassica rapa

    Institute of Scientific and Technical Information of China (English)

    Xu Yang; Yang-Jun Yu; Feng-Lan Zhang; Zhi-Rong Zou; Xiu-Yun Zhao; De-Shuang Zhang; Jia-Bing Xu

    2007-01-01

    Early bolting of Chinese cabbage (Brassica rapa L.) during spring cultivation often has detrimental effects on the yield and quality of the harvested products. Breeding late bolting varieties is a major objective of Chinese cabbage breeding programs. in order to analyze the genetic basis of bolting traits, a genetic map of B. rapa was constructed based on amplified fragment-length polymorphism (AFLP), sequence-related amplified polymorphism (SRAP), simple sequence repeat (SSR), random amplification of polymorphic DNA (RAPD), and isozyme markers. Marker analysis was carried out on 81 double haploid (DH) lines obtained by mlcrospore culture from F1 progeny of two homozygous parents: B. rapa L. ssp. pekinensis (BY) (an extra-early bolting Chinese cabbage line) and B. rapa L. ssp. rapifera (MM) (an extra-late bolting European turnip line). A total of 326 markers including 130 AFLPs, 123 SRAPs, 16 SSRs, 43RAPDs and 14 isozymes were used to construct a linkage map with 10 linkage groups covering 882 cM with an average distance of 2.71 cM between loci. The bolting trait of each DH line was evaluated by the bolting index under controlled conditions. Quantitative trait loci (QTL) analysis was conducted using multiple QTL model mapping with MapQTL5.0 software. Eight QTLs controlling bolting resistance were identified. These QTLs, accounting for 14.1% to 25.2% of the phenotyplc variation with positive additive effects, were distributed into three linkage groups. These results provide useful information for molecular marker-assisted selection of late bolting traits in Chinese cabbage breeding programs.

  5. Failure of intramedullary femoral nail with segmental breakage of distal locking bolts: a case report and review of the literature

    Institute of Scientific and Technical Information of China (English)

    Sameer Aggerwal; Nitesh Gahlot; Uttam C. Saini; Kamal Bali

    2011-01-01

    Breakage of locking bolts is an important cause of interlocking nail failure in femoral fractures. It usually occurs in the form of single breakage in one of the distal bolts of the nail or nail breakage around the distal locking hole. Here we report an unusual case of intramedullary femoral nail failure with segmental breakage of both the distal locking bolts. Such a scenario usually complicates further management. We successfully managed this case with exchange nailing without bone grafting. Here we briefly reviewed the literature regarding such an unusual presentation and discussed in detail the possible etiology of such a presentation and the management options when facing such a complex situation.

  6. Centrosome positioning in non-dividing cells.

    Science.gov (United States)

    Barker, Amy R; McIntosh, Kate V; Dawe, Helen R

    2016-07-01

    Centrioles and centrosomes are found in almost all eukaryotic cells, where they are important for organising the microtubule cytoskeleton in both dividing and non-dividing cells. The spatial location of centrioles and centrosomes is tightly controlled and, in non-dividing cells, plays an important part in cell migration, ciliogenesis and immune cell functions. Here, we examine some of the ways that centrosomes are connected to other organelles and how this impacts on cilium formation, cell migration and immune cell function in metazoan cells.

  7. Americans Divided Over Organic, GM Foods: Poll

    Science.gov (United States)

    ... gov/news/fullstory_162314.html Americans Divided Over Organic, GM Foods: Poll Their opinions aren't driven by politics ... News) -- Americans are split on the value of organic foods and concerns about genetically modified (GM) foods, a ...

  8. Environmental Aesthetics. Crossing Divides and Breaking Ground

    NARCIS (Netherlands)

    Drenthen, M.; Keulartz, J.

    2014-01-01

    Environmental aesthetics crosses several commonly recognized divides: between analytic and continental philosophy, Eastern and Western traditions, universalizing and historicizing approaches, and theoretical and practical concerns. This volume sets out to show how these,perspectives can be brought i

  9. Energy conserving effects of dividing wall column☆

    Institute of Scientific and Technical Information of China (English)

    Jing Fang; Hanmei Zhao; Jianchao Qi; Chunli Li; Junjie Qi; Jiajia Guo

    2015-01-01

    The energy-conserving performance of dividing wal column (DWC) is discussed in this paper. The heat transfer through the dividing wall is considered and the results are compared with that of common heat insulation dividing wall column (HIDWC). Based on the thermodynamic analysis of heat transfer dividing wall column (HTDWC) and HIDWC, both computer simulation and experiments are employed to analyze the energy-conserving situation. Mixtures of n-hexane, n-heptane and n-octane are chosen as the example for separation. The results show that the energy consumption of HTDWC is 50.3%less than that of conventional distillation column, while it is 46.4% less than that of HIDWC. It indicates that DWC is efficient on separating three-component mixtures and HTDWC can save more energy than HIDWC. Thus it is necessary to consider the heat transfer while applying DWC to industry.

  10. Experimental characterization of damage at countersunk bolted joints tested under quasi-static bearing loads

    Science.gov (United States)

    Popescu, Alexandru Paul

    The use of composite materials in aerospace vehicles has allowed for creation of lighter structures that provide excellent stiffness. Although they allow for easy disassembly and inspection of critical assemblies, bolted joints are common damage initiation sites in composite structures. In order for aging aircraft to be considered for life extension programs, the damage at these locations must be characterized and well-understood. Failure studies require that data be provided through experimental tests. The drawback of the present test standard for bolted composite joints is that it was initially designed for testing polymers. This thesis discusses deficiencies in the measurement of bearing strength as a result of this shortcoming, although the battery of bearing tests is modeled after this established test standard. The goal of the present work is to characterize the bearing load induced damage in laminates with pin bearing and countersunk fasteners through a series of bearing tests on laminated composites using a new modified ASTM D5961 fixture designed for testing countersunk bolted joints. This thesis examines variations in measurement of bearing strength that comes with using different test fixtures. The reliability of each test fixture to represent real conditions is evaluated using test fixtures that represent real joint configurations. Results for damage conditions and joint responses are compared. This thesis presents a study of the damage initiation and accumulation in composite specimens loaded in bearing using three different test fixtures: Procedure A, Procedure C, and Procedure A Modified. Procedure A, which is used to load the test specimen in double-shear via a straight pin, is a well known test fixture that comes from ASTM D5961. Procedure C has a countersunk fastener that loads the test specimen in single-shear. These types of fasteners are preferred in the aerospace industry over traditional bolts in order to maintain a smooth aerodynamic profile

  11. 栓焊结合钢桥高强度螺栓施工质量控制%Construction Quality Control of High-Strength Bolts for a Bolted and Welded Steel Bridge

    Institute of Scientific and Technical Information of China (English)

    张志伟; 文世军; 高琳琳

    2012-01-01

    To ensure the construction quality of the big hexagonal head high-strength bolts, the construction quality of the bolted steel truss girder members (used with the frictional type big hexagonal head bolt sets) of Fenfangwan Changjiang River Bridge is cited as an example. The construction quality of the bolts is discussed from the following aspects of the principal'parame-ters, checking, acceptance and storage of the bolts delivered to the construction site; the site torque moment test, selection and utilization of the tightening spanners, handling of the frictional surfaces; the construction technology of the bolts, construction sequences of the welded and bolted connection and also the checking, acceptance and corrosion protection of the bolts. The construction practice of the bridge-proves that in the process of the construction, the construction strictly following the formulated quality control requirements for the high-strength bolts can well control the various procedures related to the construction quality of the bolts and control the qualification ratios of the bolts in all aspects of the construction methods, construction requirements and construction technology.%为了保证大六角高强度螺栓施工质量,以重庆粉房湾长江大桥钢桁梁杆件栓接(摩擦型高强度大六角头螺栓连接副)施工及质量控制为背景,从高强度螺栓的主要参数、高强度螺栓进场验收及保管、工地扭矩系数试验、扭力扳手的选择及使用、摩擦面的处理、大六角头高强度螺栓施工工艺、栓焊结合型高强度螺栓施工顺序、高强度螺栓的验收及防腐等方面进行讨论.实践表明,在高强度螺栓施工过程中,严格按照制定的质量控制要求进行施工,从施工方法、施工要求、施工工艺上,对涉及高强度螺栓质量的各个环节进行把关,可以较好地控制高强度螺栓的终拧合格率.

  12. Fuzzy Comprehensive Evaluation of Bolt Support Effects in Deep-Mining Gateway%回采巷道锚杆支护效果模糊综合评判

    Institute of Scientific and Technical Information of China (English)

    申艳梅; 韦四江

    2011-01-01

    Bolt support has become the main form of surrounding rock control in deep-mining gateway. Good or bad supporting effect, is related not only to the support patterns, but also to the surrounding rock properties and mining conditions. To evaluate the bolt support effect in gateway accurately, taking the gateways in Pingdingshan MiningArea as the research object, 32 deep-mining gateways are selected as samples to study in this paper. Based on seven indexes such as surrounding rock strength, support strength, gateway depth, surrounding rock integrity, mining influence, gateway section and coal pillar width, etc, the bolt support effects in gateway can be divided into four kinds including better, good, common and poor by the fuzzy clustering analysis. Based on the above method, the bolt support effect in new driving gateway is pre-evaluated under given conditions, which provides the basis for bolting parameters, determination.%锚杆支护已成为深井巷道围岩控制的主要形式,支护效果的好坏除与所采用的支护方式有关外,还与围岩性质、开采条件有关,为准确评判回采巷道锚杆支护效果,以平顶山矿区深部回采巷道为研究对象,选取32条回采巷道为样本,依据围岩强度、支护强度、巷道埋深、围岩完整性、采动影响、巷道断面、煤柱宽度等7个指标,采用模糊聚类分析的方法将巷道围岩支护效果分成好、较好、一般、差4类.据此对新掘巷道给定条件下的支护效果进行预判,为锚杆支护参数确定提供依据.

  13. Applied on bolting-cable anchor support of full-seam roadway in weaker thick coal seam

    Institute of Scientific and Technical Information of China (English)

    赵庆彪; 张生华; 郭励生

    2003-01-01

    The designing method and the supporting mechanism of both bolt and small cable anchor for full-seam roadway in the weaker thick coal seam are systematically analyzed, and the construction technology and the supporting results are briefly summarized.

  14. Efficiency of low versus high airline pressure in stunning cattle with a pneumatically powered penetrating captive bolt gun.

    Science.gov (United States)

    Oliveira, Steffan Edward Octávio; Gregory, Neville George; Dalla Costa, Filipe Antonio; Gibson, Troy John; Paranhos da Costa, Mateus José Rodrigues

    2017-08-01

    The efficiency of stunning cattle was assessed in 443 animals (304 pure Zebu and 139 crossbred cattle), being mainly mature bulls and cows. Cattle were stunned using a Jarvis pneumatically powered penetrating captive bolt gun operating with low (160-175psi, N=82) and high (190psi, N=363) airline pressure, which was within the manufactures specifications. Signs of brain function and the position of the shots on the heads were recorded after stunning. Velocity of the captive bolt and its physical parameters were calculated. Cattle shot with low pressures showed more rhythmic respiration (27 vs. 8%, Pairline pressures (15.3 vs. 3.1%). Bolt velocity and its physical parameters were significantly (PAirline pressures below 190psi are inappropriate when shooting adult Zebu beef cattle with pneumatically powered penetrating captive bolt guns. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Early Bolting in Short Days: An Arabidopsis Mutation That Causes Early Flowering and Partially Suppresses the Floral Phenotype of leafy

    National Research Council Canada - National Science Library

    Concepción Gómez-Mena; Manuel Piñeiro; José M. Franco-Zorrilla; Julio Salinas; George Coupland; José M. Martínez-Zapater

    2001-01-01

    .... Some of these signals promote the onset of flowering, whereas others repress it. We describe here the isolation and characterization of two allelic mutations that cause early flowering and define a new locus, EARLY BOLTING IN SHORT DAYS (EBS...

  16. 压水堆反应堆压力容器密封主螺栓预紧过程模拟%Simulation of Bolt-up Process for Seal Main Bolts of PWR Pressure Vessel

    Institute of Scientific and Technical Information of China (English)

    陈宝

    2015-01-01

    建立了我国自主压水堆反应堆压力容器分析模型,采用通用结构分析软件ABAQUS对密封主螺栓的预紧过程进行了模拟分析。通过计算,可以得到螺栓载荷的变化、上下法兰的变形过程,从而判断螺栓加载荷顺序和大小是否合理。对于一回路压力容器的密封预紧操作具有很好的参考价值。%The reactor pressure vessel of self-owned pressure water reactor (PWR) is built, and the bolt-up process for main bolts is analyzed in this paper. According to the calculation, the change of the pre-load on the bolts and the deformation of the main flange can be checked, and a lot of useful conclusions can be got, such as whether the bolt-load of every step is good or not, whether the bolt groups are good or not. The simulation results of this paper are very meaningful for the bolt-up process operation of the first loop pressure vessel.

  17. The Nuts and Bolts of Zinc-Nickel: OEM Zinc Nickel Implementation on Fasteners - Getting It Into Production

    Science.gov (United States)

    2014-11-01

    Blake Simpson Louie Tran The Nuts and Bolts of Zinc- Nickel OEM Zinc Nickel Implementation on Fasteners – Getting It Into Production Report...REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE The Nuts and Bolts of Zinc- Nickel : OEM Zinc Nickel Implementation on...currently in production 2. Problem at Hand – Hexavalent Chromates 3. Transition to Zinc- Nickel 4. Preliminary Testing 5. Plan moving forward for

  18. Orbital angular momentum divider of light

    CERN Document Server

    Dong, Hailong Zhou Jianji; Cai, Xinlun; Yu, SiYuan; Zhang, Xinliang

    2016-01-01

    Manipulation of orbital angular momentum (OAM) of light is essential in OAM-based optical systems. Especially, OAM divider, which can convert the incoming OAM mode into one or several new smaller modes in proportion at different spatial paths, is very useful in OAM-based optical networks. However, this useful tool was never reported yet. For the first time, we put forward a passive OAM divider based on coordinate transformation. The device consists of a Cartesian to log-polar coordinate converter and an inverse converter. The first converter converts the OAM light into a rectangular-shaped plane light with a transverse phase gradient. And the second converter converts the plane light into multiple diffracted light. The OAM of zeroth-order diffracted light is the product of the input OAM and the scaling parameter. The residual light is output from other diffracted orders. Furthermore, we extend the scheme to realize equal N-dividing of OAM and arbitrary dividing of OAM. The ability of dividing OAM shows huge p...

  19. Wideband unbalanced waveguide power dividers and combiners

    Energy Technology Data Exchange (ETDEWEB)

    Halligan, Matthew; McDonald, Jacob Jeremiah; Strassner, II, Bernd H.

    2016-05-17

    The various technologies presented herein relate to waveguide dividers and waveguide combiners for application in radar systems, wireless communications, etc. Waveguide dividers-combiners can be manufactured in accordance with custom dimensions, as well as in accordance with waveguide standards such that the input and output ports are of a defined dimension and have a common impedance. Various embodiments are presented which can incorporate one or more septum(s), one or more pairs of septums, an iris, an input matching region, a notch located on the input waveguide arm, waveguide arms having stepped transformer regions, etc. The various divider configurations presented herein can be utilized in high fractional bandwidth applications, e.g., a fractional bandwidth of about 30%, and RF applications in the Ka frequency band (e.g., 26.5-40 GHz).

  20. Analogue Divider by Averaging a Triangular Wave

    Science.gov (United States)

    Selvam, Krishnagiri Chinnathambi

    2017-08-01

    A new analogue divider circuit by averaging a triangular wave using operational amplifiers is explained in this paper. The triangle wave averaging analog divider using operational amplifiers is explained here. The reference triangular waveform is shifted from zero voltage level up towards positive power supply voltage level. Its positive portion is obtained by a positive rectifier and its average value is obtained by a low pass filter. The same triangular waveform is shifted from zero voltage level to down towards negative power supply voltage level. Its negative portion is obtained by a negative rectifier and its average value is obtained by another low pass filter. Both the averaged voltages are combined in a summing amplifier and the summed voltage is given to an op-amp as negative input. This op-amp is configured to work in a negative closed environment. The op-amp output is the divider output.

  1. Effect of pre-tensioned rock bolts on stress redistribution around a roadway - insight from numerical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Fu-qiang Gao; Hong-pu Kang [Central Coal Research Institute, Beijing (China). Mining and Designing Branch

    2008-12-15

    The importance of the pre-tensioned force of rock bolts has been recognized by more and more researchers. To investigate the effect of pre-tensioned rock bolts on stress redistribution around roadways, a numerical analysis was carried out on a level drift at Chengzhuang coal mine using FLAC3D and a special post-process methodology, using surfer, is proposed to process the numerical simulation results. The results indicate that pre-tensioned rock bolts have a significant effect on stress redistribution around a roadway. In the roof, pre-tensioned rock bolts greatly increase vertical stress; as a result, the strength of the rock mass increased significantly which results in a greater capacity of bearing a large horizontal stress. The horizontal stress decreases in the upper section of the roof, indicating that pre-tensioned rock bolts significantly reduce the coefficient and the size of the region concentration of horizontal stress. At the lateral side, pre-tensioned rock bolts greatly increase the horizontal stress; therefore, the rock mass strength significantly increases which results also in a greater capacity of bearing a large vertical stress. The greater the size of pre-tensioned force, the larger the region of stress redistribution around a roadway is affected and the higher the size of the stress on the roadway surface the more the rock mass strength increases. 10 refs., 6 figs., 1 tab.

  2. Effect of pre-tensioned rock bolts on stress redistribution around a roadway insight from numerical modeling

    Institute of Scientific and Technical Information of China (English)

    GAO Fu-qiang; KANG Hong-pu

    2008-01-01

    The importance of the pre-tensioned force of rock bolts has been recognized by more and more researchers. To investigate the effect of pre-tensioned rock bolts on stress redistribution around roadways, a numerical analysis was carded out using FLAC3D and a special post-process methodology, using surfer, is proposed to process the numerical simulation results. The results indicate that pre-tensioned rock bolts have a significant effect on stress redistribution around a roadway. In the roof, pre-tensioned rock bolts greatly increase vertical stress; as a result, the strength of the rock mass increased significantly which results in a greater capacity of bearing a large horizontal stress. The horizontal stress decreases in the upper section of the roof, indicating that pre-tensioned rock bolts significantly reduce the coefficient and the size of the region concentration of horizontal stress. At the lateral side, pre-tensioned rock bolts greatly increase the horizontal stress; therefore, the rock mass strength significantly increases which results also in a greater capacity of bearing a large vertical stress. The greater the size of pre-tensioned force, the larger the region of stress redistribution around a roadway is affected and the higher the size of the stress on the roadway surface the more the rock mass strength increases.

  3. Variables Affecting Probability of Detection in Bolt Hole Eddy Current Inspection

    Science.gov (United States)

    Lemire, H.; Krause, T. W.; Bunn, M.; Butcher, D. J.

    2009-03-01

    Physical variables affecting probability of detection (POD) in a bolt-hole eddy current inspection were examined. The POD study involved simulated bolt holes in 7075-T6 aluminum coupons representative of wing areas on CC-130 and CP-140 aircraft. The data were obtained from 24 inspectors who inspected 468 coupons, containing a subset of coupons with 45 electric discharge machined notches and 72 laboratory grown fatigue cracks located at the inner surface corner of the bi-layer structures. A comparison of physical features of cracks and notches in light of skin depth effects and probe geometry was used to identify length rather than depth as the significant variable producing signal variation. Probability of detection based on length produced similar results for the two discontinuity types, except at lengths less than 0.4 mm, where POD for cracks was found to be higher than that of notches.

  4. On the performance of Usain Bolt in the 100 m sprint

    Science.gov (United States)

    Hernández Gómez, J. J.; Marquina, V.; Gómez, R. W.

    2013-09-01

    Many university texts on mechanics consider the effect of air drag force, using the slowing down of a parachute as an example. Very few discuss what happens when the drag force is proportional to both u and u2. In this paper we deal with a real problem to illustrate the effect of both terms on the speed of a runner: a theoretical model of the world-record 100 m sprint of Usain Bolt during the 2009 World Championships in Berlin is developed, assuming a drag force proportional to u and to u2. The resulting equation of motion is solved and fitted to the experimental data obtained from the International Association of Athletics Federations, which recorded Bolt's position with a laser velocity guard device. It is worth noting that our model works only for short sprints.

  5. Rock mass movements around development workings in various density of standing-and-roof-bolting support

    Institute of Scientific and Technical Information of China (English)

    MAJCHERCZYK Tadeusz; MALKOWSKLI Piotr; NIEDBALSKI Zbighiew

    2008-01-01

    Presented measurement results of roof rocks and wall rock movements of un-derground development workings after their drifting. The research was carried out in thecoal mine workings with standing-and-roof bolting support. There were various density ofthe support, so the aim of the special monitoring programme was to determine movementintensity of rock mass in the premises of the heading area. There were four types of re-search did by the authors. They measured convergence, roof layers separation using tell-tales and sonic probes and load bearing of the headings' roofs by hydraulic dynamometers.Evaluation of fracture zone around the heading and investigation the load zone caused byfailed roof rocks may become a basement for the determination of support parameters ofthe workings. The combined system of standing support and roof bolting seems to be anessential for underground headings protection.

  6. Flanged joints with contact outside the bolt circle: ASME Part B design rules

    Energy Technology Data Exchange (ETDEWEB)

    Rodabaugh, E. C.; Moore, S. E.

    1976-05-01

    The ASME Boiler and Pressure Vessel Code, Section VIII, Division 1, gives rules which are subdivided into ''Part A'' and ''Part B''. Part A covers flanged joints where contact between flanges occurs through a gasket located inside the bolt holes. Part B covers flanged joints with contact outside the bolt holes. This report (a) summarizes the theory for Part B flanged joints, (b) presents examples which show the significant differences between Part A flanged joints and Part B flanged joints, (c) presents the available test data relevant to the characteristics of Part B flanged joints, (d) gives listings of two computer programs which can be used to evaluate the characteristics of Part B flanged joints, and (e) gives recommendations for Code revisions and other aspects of Part B flanged-joint design.

  7. Bolted Joints in Composite Structures: Design, Analysis and Verification. Task II. Test Results--Multifastener Joints

    Science.gov (United States)

    1985-08-01

    Aeronautical Labs., Attn: FIBRA , Wright- Patterson AFB, OH 45433. WRDC/ASD ltr dtd 17 Oct 1990 FTrtf Kf( cry AFWAL-TR-85-3065 BOLTED JOINTS IN...removed from our mailing list, or if the addressee is no longer employed by your organization please noti fy list". AFWAL/ FIBRA , W-PAFB, OH 45433 to...test and evaluation; Aug 1985; other requests must be referred to AFWAL/ FIBRA . WPAFB. OH 45433 4. PERFORMING ORGANIZATION REPORT NUMBER(S

  8. Experimental Study on Mechanical Characteristics of Cracked Rock Mass Reinforced by Bolting and Grouting

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The stress hardening characteristics of the reinforced rock mass in uniaxial compression tests were revealed by means of the experimental study on mechanical characteristics of cracked rock mass reinforced by bolting and grouting. And the load-bearing mechanism of the reinforced rock mass was perfectly reflected by the experiment. The results can offer some useful advice for support design and stability analysis of deep drifts in unstable strata.

  9. FFTF report: drilled-in expansion bolts under static and alternating load

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, H.S.

    1976-10-01

    The objective of this investigation was to establish the allowable design loads (tension, shear, and combined load) for expansion bolts to be installed in regular 4000 psi mix concrete, Magnetite 5000 psi mix concrete, and Steel Shot 5000 psi mix concrete at the Fast Flux Test Facility. The test loads included Static Loads and Alternating Loads which simulate the dynamic loads of vibratory equipment and dynamic earthquake loads.

  10. Preload Analysis of Screw Bolt Joints on the First Wall Graphite Tiles in EAST

    Institute of Scientific and Technical Information of China (English)

    曹磊; 宋云涛

    2012-01-01

    The first wall in the Experimental Advanced Superconducting Tokamak (EAST) used graphite tiles to withstand high thermal energy. The graphite tiles are mounted on the heat sink using screw bolts which have been preloaded to produce a clamp force. The clamp force is very important to keep the graphite tiles tightly on the surface of the heat sink so that the heat flux crosses this contacting surface in a small thermal resistor. Without the clamp force, the small gap between the graphite tiles and the heat sink will make it impossible for thermal power to be carried away by cooling water. Some bolts may even fall off with the loss of clamp force. From the mathematical models, the loss process of the clamp force has been studied. Research results explain how the different thermal expansions of three members of the screw joint makes the clamp force decrease to zero under temperature rise and external force, and how the stiffness affects the relation between the clamp force and temperature. The research also gives the critical temperature at which the clamp force can remain above zero. Analysis results indicate that the current screw joints are almost destined to lose their clamp force during the running time of EAST, so the bolt joints should be redesigned in order to improve its reliability.

  11. Roof strata horizontal movement assessed by instrumented bolts monitoring and FEM modelling

    Energy Technology Data Exchange (ETDEWEB)

    Pytel, W. [CBPM ' ' Cuprum' ' OBR (Poland)

    2004-07-01

    Results of investigation concerning in-situ assessment of roof strata 3-d movement in the vicinity of a selected hard rock yielding pillar are presented in the paper. Based on laboratory calibration tests it was possible to establish the analytical relationships between the load (or stress) increment within the bolt rod, and the extensometer read-out box increment for all pairs of extensometers, glued-in at five measurement horizons. These relationships were a base for the assessment of rod axial forces and bending moments in time domain. The finite difference method technique was used for bolt rod deflection (lateral) assessment based on the elastic beam (rod) deflection differential equation solution involving the values of in-situ measurement based bending moments. In-situ obtained measurement data were supplemented with numerical experiments performed in a large geometric scale. The numerical models based on the 3-d finite element method, represented the roof bolting-pillar-floor systems in the in-situ measurement sites conditions.

  12. Holographic description of Kerr-Bolt-AdS-dS spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, B., E-mail: bchen01@pku.edu.c [Department of Physics, and State Key Laboratory of Nuclear Physics and Technology, and Center for High Energy Physics, Peking University, Beijing 100871 (China); Ghezelbash, A.M., E-mail: masoud.ghezelbash@usask.c [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada); Kamali, V., E-mail: vkamali1362@gmail.co [Department of Campus of Bijar, Kurdistan University, Bijar (Iran, Islamic Republic of); Setare, M.R., E-mail: rezakord@ipm.i [Department of Campus of Bijar, Kurdistan University, Bijar (Iran, Islamic Republic of)

    2011-07-01

    We show that there exists a holographic 2D CFT description of a Kerr-Bolt-AdS-dS spacetime. We first consider the wave equation of a massless scalar field propagating in extremal Kerr-Bolt-AdS-dS spacetimes and find in the 'near region', the wave equation in extremal limit could be written in terms of the SL(2,R) quadratic Casimir. This suggests that there exist dual CFT descriptions of these black holes. In the probe limit, we compute the scattering amplitudes of the scalar off the extremal black holes and find perfect agreement with the CFT prediction. Furthermore we study the holographic description of the generic four-dimensional non-extremal Kerr-Bolt-AdS-dS black holes. We find that if focusing on the near-horizon region, for the massless scalar scattering in the low-frequency limit, the radial equation could still be rewritten as the SL(2,R) quadratic Casimir, suggesting the existence of dual 2D description. We read the temperatures of the dual CFT from the conformal coordinates and obtain the central charges by studying the near-horizon geometry of near-extremal black holes. We recover the macroscopic entropy from the microscopic counting. We also show that for the super-radiant scattering, the retarded Green's functions and the corresponding absorption cross sections are in perfect match with CFT prediction.

  13. Mass, Measurement, Materials, and Mathematical Modeling: The Nuts and Bolts of Extrapolation

    Directory of Open Access Journals (Sweden)

    Scott A Sinex

    2011-12-01

    Full Text Available A simple activity is described which is appropriate for any class dealing with measurement. It introduces students to the important scientific process of mathematical modeling and online collaboration. Students, working in groups, determine the mass of a bolt indirectly by extrapolation from massing the bolt with one to five nuts on it and determining the equation of the line; the y-intercept being the mass of the bolt. Students gain experience with using a balance, graphing data, and analyzing results using algebraic skills. They calculate percent error after measuring the bolt’s mass directly and can compare this with the error limits from the least squares fit. Groups enter data into a web-based form and the data is examined by the class using Google Docs in a collaborative manner. After entering data in Google Docs, the students use an interactive Excel spreadsheet to compare their results to the best-fit line obtained by linear regression (pre-built into the spreadsheet for novices. In the spreadsheet, they further explore the model to gain an understanding and examine the influence of scatter (error in the data and material density.

  14. Developing a highly reliable cae analysis model of the mechanisms that cause bolt loosening in automobiles

    Directory of Open Access Journals (Sweden)

    Ken Hashimoto

    2014-10-01

    Full Text Available In this study, we developed a highly reliable CAE analysis model of the mechanisms that cause loosening of bolt fasteners, which has been a bottleneck in automobile development and design, using a technical element model for highly accurate CAE that we had previously developed, and verified its validity. Specifically, drawing on knowledge gained from our clarification of the mechanisms that cause loosening of bolt fasteners using actual machine tests, we conducted an accelerated bench test consisting of a threedimensional vibration load test of the loosening of bolt fasteners used in mounts and rear suspension arms, where interviews with personnel at an automaker indicated loosening was most pronounced, and reproduced actual machine tests with CAE analysis based on a technical element model for highly accurate CAE analysis. Based on these results, we were able to reproduce dynamic behavior in which larger screw pitches (lead angles lead to greater non-uniformity of surface pressure, particularly around the nut seating surface, causing loosening to occur in areas with the lowest surface pressure. Furthermore, we implemented highly accurate CAE analysis with no error (gap compared to actual machine tests.

  15. Characterization of tensile and shear loading on indented PC-strand cable bolts

    Institute of Scientific and Technical Information of China (English)

    Tadolini Stephen C.; ⇑; Derycke Steven; Bhagwat Anand

    2016-01-01

    The tensile and shear strength of intrinsic bolting support systems has always been a major concern of designers. A comprehensive laboratory testing program was designed to evaluate the tensile and shear strength of individual wires and completely wound PC-strand cables. PC-strand cables with smooth wires and the recent anchorage enhancement innovation of indentation were evaluated and compared. The testing protocol detailed in ISO Standard 15630 utilizes a mandrel system that was investigated at 3 different diameters which alters the wire to mandrel ratio from 2:1 to 9:1. The results demonstrate that the difference between smooth and indented wires is statistically insignificant when larger diameter mandrels are used, and that indentation does not adversely affect strand properties and performance. Insight into the shearing mechanism and evaluation techniques are discussed with the introduction of triaxial loading to describe the PC-strand tensile and shearing mechanisms. Another important result indicates that the shear strength of PC-strand cable bolting systems has a greater shear strength value than traditional steel bar bolting systems.

  16. Bolt-grouting combined support technology in deep soft rock roadway

    Institute of Scientific and Technical Information of China (English)

    Chen Yanlong; Meng Qingbin; Xu Guang; Wu Haoshuai; Zhang Guimin

    2016-01-01

    Analyzing the mineral composition, mechanical properties and ground stress testing in surrounding rock, the study investigated the failure mechanism of deep soft rock roadway with high stress. The bolt-grouting combined support system was proposed to prevent such failures. By means of FLAC3D numer-ical simulation and similar material simulation, the feasibility of the support design and the effectiveness of support parameters were discussed. According to the monitoring the surface and deep displacement in surrounding rock as well as bolt axial load, this paper analyzed the deformation of surrounding rock and the stress condition of the support structure. The monitor results were used to optimize the proposed support scheme. The results of field monitors demonstrate that the bolt-grouting combined support tech-nology could improve the surround rock strength and bearing capacity of support structure, which con-trolled the great deformation failure and rheological property effectively in deep soft rock roadway with high stress. As a result, the long term stability and safety are guaranteed.

  17. Complication assessment and prevention strategies using midfoot fusion bolt for medial column stabilization in Charcot's osteoarthropathy

    DEFF Research Database (Denmark)

    Mehlhorn, Alexander T; Walther, Markus; Iblher, Niklas

    2016-01-01

    -up was 21.4±14.6 (mean±SDM) months, 64% of patients suffered from diabetes with a preoperative Hba1c of 8.5±2.4. The mean number of revisions per foot was 3.6±4.1. Bolt dislocation was seen in 57% of the patients following 11.3±8.5 months; in 75% of these patients bony healing occurred before dislocation......In Charcot's osteoarthropathy stabilization of the medial column of the foot was introduced in order to establish a stable foot and reduce the risk for amputation. This study was performed to analyze postoperative complications, define risk factors for those and develop strategies for prevention....... Since bolt dislocation takes place frequently, it was aimed to predict an appropriate time point for bolt removal under the condition that osseous healing has occurred. Fourteen consecutive patients with neuroosteoarthropathy of the foot and arch collapse were treated with open reduction...

  18. Numerical investigation on the position of holes for reducing stress concentration in composite plates with bolted and riveted joints

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    This paper studies the effects of fiber orientaion and holes position on stress concentration and the determination of weakened areas in the composite of glass fiber reinforced epoxy resin around the hole for joints by using the finite element method.In this study,for the observation of areas affected by stress concentration Tsai-Wu failure criterion is used to determine the failed elements and ANSYS Software is implemented for modeling.In order to compare the effect of geometric parameters on stress concen...

  19. Bridging the digital divide with mobile services

    CERN Document Server

    Yelton, Andromeda

    2013-01-01

    In this issue of Library Technology Reports, Andromeda Yelton shows how libraries can build on the breadth of this population to help bridge the digital divide and provide even greater access to information. Yelton breaks down the demographics of mobile internet users, provides examples of how different libraries are reaching out to these populations, and suggests what the future may hold for this trend.

  20. Digital divide research, achievements and shortcomings

    NARCIS (Netherlands)

    Dijk, van Jan A.G.M.

    2006-01-01

    From the end of the 1990s onwards the digital divide, commonly defined as the gap between those who have and do not have access to computers and the Internet, has been a central issue on the scholarly and political agenda of new media development. This article makes an inventory of 5 years of digita

  1. The electronic health record: a digital divide?

    Science.gov (United States)

    Glaser, John

    2007-10-01

    The gap between EHR adoption among larger providers versus adoption by smaller or rural providers has caused a "digital divide" that could threaten smaller providers' survival in the years ahead. Closing this gap will require the collective action of providers, payers, and government.

  2. Digital divide research, achievements and shortcomings

    NARCIS (Netherlands)

    van Dijk, Johannes A.G.M.

    2006-01-01

    From the end of the 1990s onwards the digital divide, commonly defined as the gap between those who have and do not have access to computers and the Internet, has been a central issue on the scholarly and political agenda of new media development. This article makes an inventory of 5 years of

  3. Young People's Internet Use: Divided or Diversified?

    Science.gov (United States)

    Boonaert, Tom; Vettenburg, Nicole

    2011-01-01

    This article critically analyses research on young people's internet use. Based on a literature analysis, it examines which young people do what on the internet. These results invite a reflection on the dominant discourse on the digital divide. Within this discourse, there is a strong focus on the use of the internet for information purposes only,…

  4. Democratisation and Conflict in Ethnically Divided Societies

    NARCIS (Netherlands)

    Vorrath, Judith; Krebs, Lutz

    2009-01-01

    This article reviews three important factors in the academic debate on ethnic civil wars: the role of ethnicity in causing and structuring violence, the spread of ethnic civil wars once they have started, and the influence of democratic transitions in divided societies. The review displays the range

  5. An Automatic Number Plate Recognition System under Image Processing

    Directory of Open Access Journals (Sweden)

    Sarbjit Kaur

    2016-03-01

    Full Text Available Automatic Number Plate Recognition system is an application of computer vision and image processing technology that takes photograph of vehicles as input image and by extracting their number plate from whole vehicle image , it display the number plate information into text. Mainly the ANPR system consists of 4 phases: - Acquisition of Vehicle Image and Pre-Processing, Extraction of Number Plate Area, Character Segmentation and Character Recognition. The overall accuracy and efficiency of whole ANPR system depends on number plate extraction phase as character segmentation and character recognition phases are also depend on the output of this phase. Further the accuracy of Number Plate Extraction phase depends on the quality of captured vehicle image. Higher be the quality of captured input vehicle image more will be the chances of proper extraction of vehicle number plate area. The existing methods of ANPR works well for dark and bright/light categories image but it does not work well for Low Contrast, Blurred and Noisy images and the detection of exact number plate area by using the existing ANPR approach is not successful even after applying existing filtering and enhancement technique for these types of images. Due to wrong extraction of number plate area, the character segmentation and character recognition are also not successful in this case by using the existing method. To overcome these drawbacks I proposed an efficient approach for ANPR in which the input vehicle image is pre-processed firstly by iterative bilateral filtering , adaptive histogram equalization and number plate is extracted from pre-processed vehicle image using morphological operations, image subtraction, image binarization/thresholding, sobel vertical edge detection and by boundary box analysis. Sometimes the extracted plate area also contains noise, bolts, frames etc. So the extracted plate area is enhanced by using morphological operations to improve the quality of

  6. Processless offset printing plates

    Directory of Open Access Journals (Sweden)

    Sanja Mahović Poljaček

    2015-06-01

    Full Text Available With the implementation of platesetters in the offset printing plate making process, imaging of the printing plate became more stable and ensured increase of the printing plate quality. But as the chemical processing of the printing plates still highly influences the plate making process and the graphic reproduction workflow, development of printing plates that do not require chemical processing for offset printing technique has been one of the top interests in graphic technology in the last few years. The main reason for that came from the user experience, where majority of the problems with plate making process could be connected with the chemical processing of the printing plate. Furthermore, increased environmental standards lead to reducing of the chemicals used in the industrial processes. Considering these facts, different types of offset printing plates have been introduced to the market today. This paper presents some of the processless printing plates.

  7. Conquering the digital divide: Botswana and South Korea digital divide status and interventions

    Directory of Open Access Journals (Sweden)

    Nonofo C. Sedimo

    2011-03-01

    Full Text Available Background: Botswana is putting in place initiatives towards establishing itself as a knowledgebased economy. Transformation from a resource-based to a knowledge-based economy is partly hinged on innovation, research and development capability, knowledge channels, and the funding of research and development activities.Objectives: Bridging the digital divide and narrowing the intra-national divide brings about global information and communication technology (ICT usage that translates into changing work patterns and eventually transformed economies. This article outlines the different interventions implemented in Botswana to bridge the divide. The South Korean experience in bridging the divide is discussed so as to serve as lessons on how to effectively bridge the divide to Botswana’s initiatives.Method: Using a mix of exploratory and empirical study, this article presents the findings on the status of ICT uptake in Botswana and investigates the level of the digital divide in the country.Results: The results of the study show that the digital divide is much more evident in Botswana than in South Korea. South Korea has put in place robust strategic initiatives towards reducing the digital divide and this has largely transcended into its transformation into a full-fledged knowledge society.Conclusion: This article is timely as it unearths the different pointers that may be utilised in policy formation and what interventions need to be taken at both the individual and national level to bridge the digital divide.

  8. Evaluation of Interlaminar Stresses in Composite Laminates with a Bolt-Filled Hole Using a Linear Elastic Traction-Separation Description

    Directory of Open Access Journals (Sweden)

    Yong Cao

    2017-01-01

    Full Text Available Determination of the local interlaminar stress distribution in a laminate with a bolt-filled hole is helpful for optimal bolted joint design, due to the three-dimensional (3D nature of the stress field near the bolt hole. A new interlaminar stress distribution phenomenon induced by the bolt-head and clamp-up load, which occurs in a filled-hole composite laminate, is investigated. In order to efficiently evaluate interlaminar stresses under the complex boundary condition, a calculation strategy that using zero-thickness cohesive interface element is presented and validated. The interface element is based on a linear elastic traction-separation description. It is found that the interlaminar stress concentrations occur at the hole edge, as well as the interior of the laminate near the periphery of the bolt head. In addition, the interlaminar stresses near the periphery of the bolt head increased with an increase in the clamp-up load, and the interlaminar normal and shear stresses are not at the same circular position. Therefore, the clamp-up load cannot improve the interlaminar stress distribution in the laminate near the periphery of the bolt head, although it can reduce the magnitude of the interlaminar shear stress at the hole edge. Thus, the interlaminar stress distribution phenomena may lead to delamination initiation in the laminate near the periphery of the bolt head, and should be considered in composite bolted joint design.

  9. Impedance-Based Pre-Stress Monitoring of Rock Bolts Using a Piezoceramic-Based Smart Washer-A Feasibility Study.

    Science.gov (United States)

    Wang, Bo; Huo, Linsheng; Chen, Dongdong; Li, Weijie; Song, Gangbing

    2017-01-27

    Pre-stress degradation or looseness of rock bolts in mining or tunnel engineering threatens the stability and reliability of the structures. In this paper, an innovative piezoelectric device named a "smart washer" with the impedance method is proposed with the aim of developing a real-time device to monitor the pre-stress level of rock bolts. The proposed method was verified through tests on a rock bolt specimen. By applying high-frequency sweep excitations (typically >30 kHz) to the smart washer that was installed on the rock bolt specimen, we observed that the variation in impedance signatures indicated the rock bolt pre-stress status. With the degradation of rock bolt pre-stress, the frequency in the dominating peak of the real part of the electrical impedance signature increased. To quantify the effectiveness of the proposed technique, a normalized root mean square deviation (RMSD) index was developed to evaluate the degradation level of the rock bolt pre-stress. The experimental results demonstrated that the normalized RMSD-based looseness index, which was computed from the impedance value detected by the "smart washer", increased with loss of the pre-stress of the rock bolt. Therefore, the proposed method can effectively detect the degradation of rock bolt pre-stress, as demonstrated by experiments.

  10. Analyzing Broadband Divide in the Farming Sector

    DEFF Research Database (Denmark)

    Jensen, Michael; Gutierrez Lopez, Jose Manuel; Pedersen, Jens Myrup

    2013-01-01

    Agriculture industry has been evolving for centuries. Currently, the technological development of Internet oriented farming tools allows to increase the productivity and efficiency of this sector. Many of the already available tools and applications require high bandwidth in both directions......, upstream and downstream connection. The main constraint is that farms are naturally located in rural areas where the required access broadband data rates are not available. This paper studies the broadband divide in relation to the Danish agricultural sector. Results show how there is an important...... difference between the broadband availability for farms and the rest of the households/buildings the country. This divide may be slowing down the potential technological development of the farming industry, in order to keep their competitiveness in the market. Therefore, broadband development in rural areas...

  11. Divided or kissing nevus of the penis.

    Science.gov (United States)

    Hardin, Carolyn A; Tieu, Kathy D

    2013-10-16

    The divided or kissing nevus is an unusual congenital melanocytic nevus. By definition, these nevi appear on skin that separates during embryological development. These lesions have been reported on the eyelids, fingers, and rarely the penis. We describe an 18 year old uncircumcised male who presented with an asymptomatic darkly pigmented patch on the glans penis. He reported that the lesion had appeared recently and was enlarging. Physical examination revealed a second symmetric lesion on the adjacent foreskin. Punch biopsy of the lesion on the glans penis showed abundant intradermal melanocytes devoid of mitoses and atypia, consistent with an intradermal melanocytic nevus. Based on the benign histologic nature and clinical exam, the lesion was diagnosed as a divided or kissing nevus of the penis. Proposed treatments include excision and grafting as well as Nd:YAG laser therapy. However, these patients may be safely monitored with regular follow-up skin examinations because there is minimal risk of malignant transformation.

  12. Identification of Flowering-Related Genes Responsible for Differences in Bolting Time between Two Radish Inbred Lines

    Science.gov (United States)

    Jung, Won Yong; Park, Hyun Ji; Lee, Areum; Lee, Sang Sook; Kim, Youn-Sung; Cho, Hye Sun

    2016-01-01

    Late bolting after cold exposure is an economically important characteristic of radish (Raphanus sativus L.), an important Brassicaceae root vegetable crop. However, little information is available regarding the genes and pathways that govern flowering time in this species. We performed high-throughput RNA sequencing analysis to elucidate the molecular mechanisms that determine the differences in flowering times between two radish lines, NH-JS1 (late bolting) and NH-JS2 (early bolting). In total, 71,188 unigenes were identified by reference-guided assembly, of which 309, 788, and 980 genes were differentially expressed between the two inbred lines after 0, 15, and 35 days of vernalization, respectively. Among these genes, 218 homologs of Arabidopsis flowering-time (Ft) genes were identified in the radish, and 49 of these genes were differentially expressed between the two radish lines in the presence or absence of vernalization treatment. Most of the Ft genes up-regulated in NH-JS1 vs. NH-JS2 were repressors of flowering, such as RsFLC, consistent with the late-bolting phenotype of NH-JS1. Although, the functions of genes down-regulated in NH-JS1 were less consistent with late-bolting characteristics than the up-regulated Ft genes, several Ft enhancer genes, including RsSOC1, a key floral integrator, showed an appropriate expression to the late-bolting phenotype. In addition, the patterns of gene expression related to the vernalization pathway closely corresponded with the different bolting times of the two inbred lines. These results suggest that the vernalization pathway is conserved between radish and Arabidopsis. PMID:28018383

  13. Identification of flowering-related genes responsible for differences in bolting time between two radish inbred lines

    Directory of Open Access Journals (Sweden)

    Hye Sun Cho

    2016-12-01

    Full Text Available Late bolting after cold exposure is an economically important characteristic of radish (Raphanus sativus L., an important Brassicaceae root vegetable crop. However, little information is available regarding the genes and pathways that govern flowering time in this species. We performed high-throughput RNA sequencing analysis to elucidate the molecular mechanisms that determine the differences in flowering times between two radish lines, NH-JS1 (late bolting and NH-JS2 (early bolting. In total, 71,188 unigenes were identified by reference-guided assembly, of which 309, 788, and 980 genes were differentially expressed between the two inbred lines after 0, 15, and 35 days of vernalization, respectively. Among these genes, 218 homologs of Arabidopsis flowering-time (Ft genes were identified in the radish, and 49 of these genes were differentially expressed between the two radish lines in the presence or absence of vernalization treatment. Most of the Ft genes up-regulated in NH-JS1 vs NH-JS2 were repressors of flowering, such as RsFLC, consistent with the late-bolting phenotype of NH-JS1. Although the functions of genes down-regulated in NH-JS1 were less consistent with late-bolting characteristics than the up-regulated Ft genes, several Ft enhancer genes, including RsSOC1, a key floral integrator, showed an appropriate expression to the late-bolting phenotype. In addition, the patterns of gene expression related to the vernalization pathway closely corresponded with the different bolting times of the two inbred lines. These results suggest that the vernalization pathway is conserved between radish and Arabidopsis.

  14. Divided libraries remodeling management to unify institutions

    CERN Document Server

    Webb, TD

    2012-01-01

    Given the highly trained library workforce now available and the vast and growing array of packaging information and knowledge, libraries have the capacity to become pre-eminent places of learning, research, and teaching. Yet, despite this potential, libraries remain divided from their constituencies and their governing bodies, be they students, faculties, university administrations, municipal governments, or ordinary citizens. Indeed, many modern university administrators, viewing librarians as ancillary citizens in academe, have allowed their libraries to wither under the burden of shrinking

  15. Nursing's divided loyalties: an historical case study.

    Science.gov (United States)

    Baer, E D

    1989-01-01

    Using the historical version of the case study method, this research explored an example of turn-of-the-century nurses' conflicted loyalties. One training school alumnae association was examined to demonstrate that nurses acted out simultaneous loyalty to competing entities: individual graduates attributes vs. associational eligibility requirements; member vs. institutions' needs; and local vs. national nursing concerns. As a result of these divided loyalties, the nurses did not meet the alumnae organizational goals they set for themselves.

  16. Parametric frequency dividers in satellite communications

    OpenAIRE

    Kosmopoulos, S. A.; Lo Forti, R.; Saggese, E.

    1990-01-01

    The performance of two different parametric frequency dividers, using GaAs varactor diodes in a balanced circuit configuration implemented by planar (microstrip) or quasi-planar (finline, coupled finline ) elements respectively, is presented. The almost phase noise free operation of these devices allows the construction of efficient miniature synthesizers or carrier recovering schemes, incorporated on the space segment of Ku- or Ka-band satellite communications systems.

  17. The Centre of Mass of a Triangular Plate

    Science.gov (United States)

    Slusarenko, Viktor; Rojas, Roberto; Fuster, Gonzalo

    2008-01-01

    We present a derivation for the coordinates of the centre of mass--or centre of gravity--of a homogeneous triangular plate by using scaling and symmetry. We scale the triangular plate by a factor of 2 and divide its area into four plates identical to the original. By symmetry, we assert that the centre of mass of two identical masses lies at the…

  18. Self-organization of divided hierarchy

    Science.gov (United States)

    Odagaki, Takashi; Kitada, Keigo; Omizo, Kenta; Fujie, Ryo

    2015-03-01

    There are two types of extreme form of hierarchy, one is the plutonomy where small fraction of winners and losers and many people in the middle class appear and the other a divided hierarchy where half of population become winners and the remaining half become losers. We study the emergence of the divided hierarchy in a model society which consists of bellicose individuals who always try to fight and fight with the strongest neighbor and pacific individuals who always try not to fight and when necessary fight with the weakest neighbor. In our model society, (1) individuals make random walk on a square lattice, (2) when two individuals encounter they fight each other and (3) the winner deprives wealth from the loser. By a Monte Carlo simulation, we show that there are two transitions when the population density is increased; one is a transition from the egalitarian society to a hierarchical society I where winners, losers and middle classes coexist and the other is a transition from the hierarchical society I to a hierarchical society II where winners and losers exist but no middle classes exist, that is the divided hierarchy. We also show that clusters consisting mostly of bellicose individuals appear in the hierarchical society I.

  19. Splicing the Divide: A Review of Research on the Evolving Digital Divide among K-12 Students

    Science.gov (United States)

    Dolan, Jennifer E.

    2016-01-01

    The digital divide has narrowed with regard to one definition of access to technology--the binary view of the "haves" and "have-nots." However, use of technology at home and in school is not equitable for all students. According to recent literature, a broader and more nuanced definition of the technological divide is necessary…

  20. An Internal ALD-Based High Voltage Divider and Signal Circuit for MCP-based Photodetectors

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Bernhard W.; Elagin, Andrey; Elam, Jeffrey W.; Frisch, Henry J.; Genat, Jean-Francois; Gregar, Joseph S.; Mane, Anil U.; Minot, Michael J.; Northrup, Richard; Obaid, Razib; Oberla, Eric; Alexander, Vostrikov; Wetstein, Matthew

    2015-04-21

    We describe a pin-less design for the high voltage (HV) resistive divider of the all-glass LAPPD (TM) 8 in,square thin photodetector module. The divider, which distributes high voltage applied to the photocathode to the two micro-channel plates (MCPs) that constitute the amplification stage, is comprised of the two MCPs and three glass mechanical spacers, each of which is coated with a resistive layer using atomic layer deposition (ALD). The three glass grid spacers and the two MCPs form a continuous resistive path between cathode and anode, with the voltages across the MCPs and the spacers determined by the resistance of each. High voltage is applied on an external tab on the top glass window that connects to the photocathode through the metal seal. The DC ground is supplied by microstrips on the bottom glass plate that form the high-bandwidth anode. The microstrips exit the package through the glass-frit seal of the anode base-plate and the package sidewall. The divider is thus completely internal, with no HV pins penetrating the low-profile flat glass package. Measurements of the performance of the divider are presented for the 8 in.-square MCP and spacer package in a custom test fixture and for an assembled externally pumped LAPPD (TM) prototype with an aluminum photocathode. (C) 2015 Elsevier B.V. All rights reserved.

  1. Component-Based Model for Single-Plate Shear Connections with Pretension and Pinched Hysteresis.

    Science.gov (United States)

    Weigand, Jonathan M

    2017-02-01

    Component-based connection models provide a natural framework for modeling the complex behaviors of connections under extreme loads by capturing both the individual behaviors of the connection components, such as the bolt, shear plate, and beam web, and the complex interactions between those components. Component-based models also provide automatic coupling between the in-plane flexural and axial connection behaviors, a feature that is essential for modeling the behavior of connections under column removal. This paper presents a new component-based model for single-plate shear connections that includes the effects of pre-tension in the bolts and provides the capability to model standard and slotted holes. The component-based models are exercised under component-level deformations calculated from the connection demands via a practical rigid-body displacement model, so that the results of the presented modeling approach remains hand-calculable. Validation cases are presented for connections subjected to both seismic and column removal loading. These validation cases show that the component-based model is capable of predicting the response of single-plate shear connections for both seismic and column removal loads.

  2. Planned complex suicide by penetrating captive-bolt gunshot and hanging: case study and review of the literature.

    Science.gov (United States)

    Viel, Guido; Schröder, Ann Sophie; Püschel, Klaus; Braun, Christian

    2009-05-30

    Captive-bolt guns or slaughterer's guns are devices widely used in meat industry and private farmer households for slaughtering animal stocks. They consist of a simple cylindrical metal tube (barrel) with a metal bolt placed in their centre (around 9-15cm long and 1-1.5cm wide). The bolt is actuated by a trigger pull and is propelled forward by compressed air or by the discharge of a blank powder gun cartridge. Violent deaths inflicted by captive-bolt guns are rarely encountered in forensic practice and are predominantly suicidal events. We report an unusual complex suicide by hanging and self-shooting with a slaughterer's gun in a 21-year-old boy. The victim after putting a ceiling fixed rope around his neck shot himself in the head (occipital region) with a Kerner captive-bolt gun. He used two mirrors (a cosmetic mirror and a man-sized one) in order to properly visualize his back and to target the occipital region of his head. Radiological data (computed tomography with three dimensional reconstruction) and autopsy findings are discussed according to the clinical and forensic literature. A brief review on planned complex suicides is also given.

  3. Regulatory analysis for the resolution of Generic Safety Issue 29: Bolting degradation or failure in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Chang, T.Y.

    1991-09-01

    Generic Safety Issue (GSI)-29 deals with staff concerns about public risk due to degradation or failure of safety-related bolting in nuclear power plants. The issue was initiated in November 1982. Value-impact studies of a mandatory program on safety-related bolting for operating plants were inconclusive: therefore, additional regulatory requirements for operating plants could not be justified in accordance with provisions of 10 CFR 50.109. In addition, based on operating experience with bolting in both nuclear and conventional power plants, the actions already taken through bulletins, generic letters, and information notices, and the industry-proposed actions, the staff concluded that a sufficient technical basis exists for the resolution of GSI-29. The staff further concluded that leakage of bolted pressure joints is possible but catastrophic failure of a reactor coolant pressure boundary joint that will lead to significant accident sequences is highly unlikely. For future plants, it was concluded that a new Standard Review Plant section should be developed to codify existing bolting requirements and industry-developed initiatives. 9 refs., 1 tab.

  4. Testing of nuclear grade lubricants and their effects on A540 B24 and A193 B7 bolting materials

    Energy Technology Data Exchange (ETDEWEB)

    Czajkowski, C.J.

    1985-01-01

    An investigation was performed on eleven commonly used lubricants by the nuclear power industry. The investigation included EDS analysis of the lubricants, notched-tensile constant extension rate testing of bolting materials with the lubricants, frictional testing of the lubricants and weight loss testing of a bonded solid film lubricant. The report generally concludes that there is a significant amount of variance in the mechanical properties of common bolting materials; that MoS/sub 2/ can hydrolyze to form H/sub 2/S at 100/sup 0/C and cause stress corrosion cracking (SCC) of bolting materials, and that the use of copper-containing lubricants can be potentially detrimental to high strength steels in an aqueous environment. Additionally, the testing of various lubricants disclosed that some lubricants contain potentially detrimental elements (e.g. S, Sb) which can promote SCC of the common bolting materials. One of the most significant findings of this report is the observation that both A193 B7 and A540 B24 bolting materials are susceptible to transgranular stress corrosion cracking in demineralized H/sub 2/O at 280/sup 0/C in notched tensile tests.

  5. The private – public law divide

    DEFF Research Database (Denmark)

    Gyldenløve Jeppesen-de Boer, Christina; Kronborg, Annette; Svendsen, Idamarie Leth

    2013-01-01

    to a particular societal institution. Marriage as an institution has been individualized and the goodness of the family has to relate to the well-being of the individuals instead. This article shows that within this historical development the private-public law divide has not been seriously challenged......In a Scandinavian perspective, the family and the individual have changed places during the 20th Century. Today, the law takes its starting point in the individual - not in the family. A consequence of this development is that it is no longer legally possible to relate the good family...

  6. CMOS Direct-Injection Divide-by-3 Injection-Locked Frequency Dividers

    Institute of Scientific and Technical Information of China (English)

    Chia-Wei; Chang; Jhin-Fang; Huang; Sheng-Lyang; Jang; Ying-Hsiang; Liao; Miin-Horng; Juang

    2010-01-01

    <正>This paper proposes CMOS LC-tank divide-by-3 injection locked frequency dividers(ILFDs)fabricated in 0.18μn and 90nm CMOS process and describes the circuit design,operation principle and measurement results of the ILFDs.The ILFDs use two injection series-MOSFETs across the LC resonator and a differential injection signal is applied to the gates of injection MOSFETs.The direct-injection divide-by-3 ILFDs are potential for radio-frequency application and can have wide locking range.

  7. America's digital divide: 2000-2003 trends.

    Science.gov (United States)

    Whaley, Kermit C

    2004-04-01

    Computer ownership and literacy, along with Internet access and its many applications, has become, for many, a trademark for the Americans' lifestyle. Research shows that computer ownership and literacy, along with Internet access and expertise, is rapidly changing how Americans go about their business. The technological industry is providing many opportunities for Americans to operate in markets, global and local, not previously available. These changes are apparent across all U.S. sociocultural and geographic boundaries. Yet, upon close analysis, there are individuals and communities less connected with many completely excluded from participation. Those individuals exist below a line called the Digital Divide. Growth in computer ownership and Internet use, while offering optimism that the Digital Divide is narrowing, also illustrates that, without focused intervention will for certain populations, continue. Public and private programs, focus groups, and pocks of community activism, each hope to correct the disparities among on- and-off line Americans. On many fronts, there is evidence that progress is being made by many. Income, race, age, and geographic location are often the determining factors.

  8. Media Literacy in Times of Media Divides

    Directory of Open Access Journals (Sweden)

    Kaja Žuran

    2013-12-01

    Full Text Available We live in a post-modern society, an information society, a society based around knowledge and participation, and above all in a media society. In a media culture where media holds a dominant position, we cannot overlook the emerging idea of a ‘media divide’ within the frame of media education, media literate individuals and the expansion of the traditional concept of media literacy. Firstly, we are in an era of technological revolution, and it is time to consider the meaning and function of media and how we experience it in our everyday life. Secondly, as a society we are subject to intense media invasion and we all need to learn how to use it to our benefit and apply a critical and autonomous perspective towards selecting media content. Otherwise the media divide between the media literate and illiterate will widen; but is there even a chance to overcome the supposed divide between those who are formally media educated and those who are not?

  9. Create Your Plate

    Medline Plus

    Full Text Available ... steps to get started: Using your dinner plate, put a line down the middle of the plate. ... vegetables . Now in one of the small sections, put grains and starchy foods. See this list of ...

  10. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate It's simple and effective for both managing diabetes and losing weight. Creating your plate lets ... 2016 Articles from Diabetes Forecast® magazine: wcie-meal-planning, In this section Food Planning Meals Diabetes Meal ...

  11. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal ... Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook ...

  12. Food guide plate

    Science.gov (United States)

    ... chips or cookies. VEGETABLES: MAKE HALF OF YOUR PLATE FRUITS AND VEGETABLES Vegetables can be raw, fresh, ... as a snack. FRUITS: MAKE HALF OF YOUR PLATE FRUITS AND VEGETABLES Fruits can be fresh, canned, ...

  13. Growth Plate Fractures

    Science.gov (United States)

    ... the most widely used by doctors is the Salter-Harris system, described below. Type I Fractures These ... incidence of growth plate fractures peaks in adolescence. Salter-Harris classification of growth plate fractures. AAOS does ...

  14. Create Your Plate

    Medline Plus

    Full Text Available ... Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook ... Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart- ...

  15. Create Your Plate

    Medline Plus

    Full Text Available ... Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook ... Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart- ...

  16. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate It's simple and effective for both managing diabetes and losing weight. Creating your plate lets you still choose the foods you want, but changes the portion sizes so you are getting larger ...

  17. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate It's simple and effective for both managing diabetes and losing weight. Creating your plate lets ... Sleeve Custom jerseys for your Tour de Cure team benefits the cause. Ask the Experts: Learn to ...

  18. Accelerated plate tectonics.

    Science.gov (United States)

    Anderson, D L

    1975-03-21

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

  19. The nuts and bolts of proofs an introduction to mathematical proofs

    CERN Document Server

    Cupillari, Antonella

    2005-01-01

    The Nuts and Bolts of Proof instructs students on the basic logic of mathematical proofs, showing how and why proofs of mathematical statements work. It provides them with techniques they can use to gain an inside view of the subject, reach other results, remember results more easily, or rederive them if the results are forgotten.A flow chart graphically demonstrates the basic steps in the construction of any proof and numerous examples illustrate the method and detail necessary to prove various kinds of theorems.* The "List of Symbols" has been extended.* Set Theory section has been strengthened with more examples and exercises.* Addition of "A Collection of Proofs"

  20. Ricci flows connecting Taub-Bolt and Taub-NUT metrics

    Energy Technology Data Exchange (ETDEWEB)

    Holzegel, Gustav [University of Cambridge, DAMTP, Wilberforce Road, Cambridge, CB1 0WA (United Kingdom); Schmelzer, Thomas [University of Oxford, Computing Laboratory, Wolfson Building, Parks Road, Oxford, OX1 3QD (United Kingdom); Warnick, Claude [University of Cambridge, DAMTP, Wilberforce Road, Cambridge, CB1 0WA (United Kingdom)

    2007-12-21

    We use the Ricci flow with surgery to study four-dimensional SU(2) x U(1)-symmetric metrics on a manifold with fixed boundary given by a squashed 3-sphere. Depending on the initial metric we show that the flow converges to either the Taub-Bolt or the Taub-NUT metric, the latter case potentially requiring surgery at some point in the evolution. The Ricci flow allows us to explore the Euclidean action landscape within this symmetry class. This work extends the recent work of Headrick and Wiseman (2006 Class. Quantum Grav. 23 6683) to more interesting topologies.

  1. New bolting structure of fractured roof based on the Bossinesq equations

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Present support theories contain a number of shortcomings in the designation of fractured roof bolt parameters of rectangular or trapezoidal coal roadways.Roof fall accidents occur easily in this kind of roadway.Based on the Bossinesq equations and the Mohr strength theory,we propose a theory of an anchored cluster structure for fractured roofs and have investigated the formation of such an anchored cluster structure,its self stability mechanism and mechanical properties.The results show that an anchor and ...

  2. On the plastic behaviour of multi directional epoxy-bolted CFRP laminates

    DEFF Research Database (Denmark)

    Jensen, Aage; Poulsen, Ervin

    2004-01-01

    The second generation of CFRP laminate has recently been developed. It is a multi directional CFRP laminate, i.e. a laminate with carbon fibres having several directions other than the first generation. The paper describes the laboratory tests carried out in order to develop anchorage devices for...... for such multi directional CFRP laminates which are epoxy-bonded and bolted or nailed to the concrete substrate for the purpose of strengthening against failure caused by bending. The tests were carried out at the Technical University of Denmark, IABM and Byg-DTU...

  3. Create Your Plate

    Medline Plus

    Full Text Available ... Reset Plate Share Create Your Plate ! Share: Seven Simple Steps to Create Your Plate It's simple and effective for both managing diabetes and losing ... en.html Have Type 2 Diabetes? Our free program will help you live well. More from diabetes. ...

  4. Obliquity along plate boundaries

    Science.gov (United States)

    Philippon, Mélody; Corti, Giacomo

    2016-12-01

    Most of the plate boundaries are activated obliquely with respect to the direction of far field stresses, as roughly only 8% of the plate boundaries total length shows a very low obliquity (ranging from 0 to 10°, sub-orthogonal to the plate displacement). The obliquity along plate boundaries is controlled by (i) lateral rheological variations within the lithosphere and (ii) consistency with the global plate circuit. Indeed, plate tectonics and magmatism drive rheological changes within the lithosphere and consequently influence strain localization. Geodynamical evolution controls large-scale mantle convection and plate formation, consumption, and re-organization, thus triggering plate kinematics variations, and the adjustment and re-orientation of far field stresses. These geological processes may thus result in plate boundaries that are not perpendicular but oblique to the direction of far field stresses. This paper reviews the global patterns of obliquity along plate boundaries. Using GPlate, we provide a statistical analysis of present-day obliquity along plate boundaries. Within this framework, by comparing natural examples and geological models, we discuss deformation patterns and kinematics recorded along oblique plate boundaries.

  5. Numerical and experimental analysis on load sharing & optimization of the joint parameters of polymer composite multi bolted joints

    Science.gov (United States)

    Latha Shankar, B.; Sudeep Kumar, T.; Shiva Shankar, G. S.

    2016-09-01

    In the present work, the bearing failure of composite bolted connections of composite laminates was analysed both experimentally and numerically. The glass fiber woven mat 600GSM/ epoxy composite laminates were prepared using wet-layup technique. The process parameters were taken care during preparation of laminates. Examination is done for various estimations of edge-to-hole diameter and width-to-hole diameter proportion. Stress is evaluated in laminates by utilizing Hart-Smith criteria. Ideal estimation of e/d proportion, d/w proportion is recommended for most extreme effectiveness. A numerical technique is utilized for the rough determination of a load shared by bolts in a numerous "bolted" joints loaded in tension were investigated experimentally and numerically. The effect of un-evenness in load shearing is suggested.

  6. VALIDITY OF THE HIGH-TENSILE-STRENG TH BOLT FOR THE SOFT ROCK WITH LARGE CROSS SECTIONAL TUNNEL

    Science.gov (United States)

    Yagi, Hiroshi; Tamamura, Kouji; Uneda, Atsushi; Domon, Tsuyoshi; Nishimura, Kazuo

    This paper reports the experiential result about the applications of the high tensile strength bolts as a countermeasure for the displacement, considered about the denaturalization of the large cross sectional tunnel in mudstone layer. In Kanaya Tunnel of the New Tomei Expressway, the soft rock section appeared where we cannot restrain support denaturizi ng and internal displacement by materials of the standard design. Then fore, we adopted the high tensile strength bolts (748kN) replacing with of the standard design, and improved the support proof for stress. As the result, we got possible to control the displacement and execute the work safety and economi cally. We compared the analysis result (FEM) by the limited element method with the measure result on the spot, and inspected the supportability effect of the higt tensile strength bolts.

  7. Measurement of the Length of Installed Rock Bolt Based on Stress Wave Reflection by Using a Giant Magnetostrictive (GMS) Actuator and a PZT Sensor

    Science.gov (United States)

    Luo, Mingzhang; Li, Weijie; Wang, Bo; Fu, Qingqing; Song, Gangbing

    2017-01-01

    Rock bolts, as a type of reinforcing element, are widely adopted in underground excavations and civil engineering structures. Given the importance of rock bolts, the research outlined in this paper attempts to develop a portable non-destructive evaluation method for assessing the length of installed rock bolts for inspection purposes. Traditionally, piezoelectric elements or hammer impacts were used to perform non-destructive evaluation of rock bolts. However, such methods suffered from many major issues, such as the weak energy generated and the requirement for permanent installation for piezoelectric elements, and the inconsistency of wave generation for hammer impact. In this paper, we proposed a portable device for the non-destructive evaluation of rock bolt conditions based on a giant magnetostrictive (GMS) actuator. The GMS actuator generates enough energy to ensure multiple reflections of the stress waves along the rock bolt and a lead zirconate titantate (PZT) sensor is used to detect the reflected waves. A new integrated procedure that involves correlation analysis, wavelet denoising, and Hilbert transform was proposed to process the multiple reflection signals to determine the length of an installed rock bolt. The experimental results from a lab test and field tests showed that, by analyzing the instant phase of the periodic reflections of the stress wave generated by the GMS transducer, the length of an embedded rock bolt can be accurately determined. PMID:28241503

  8. Measurement of the Length of Installed Rock Bolt Based on Stress Wave Reflection by Using a Giant Magnetostrictive (GMS) Actuator and a PZT Sensor.

    Science.gov (United States)

    Luo, Mingzhang; Li, Weijie; Wang, Bo; Fu, Qingqing; Song, Gangbing

    2017-02-23

    Rock bolts, as a type of reinforcing element, are widely adopted in underground excavations and civil engineering structures. Given the importance of rock bolts, the research outlined in this paper attempts to develop a portable non-destructive evaluation method for assessing the length of installed rock bolts for inspection purposes. Traditionally, piezoelectric elements or hammer impacts were used to perform non-destructive evaluation of rock bolts. However, such methods suffered from many major issues, such as the weak energy generated and the requirement for permanent installation for piezoelectric elements, and the inconsistency of wave generation for hammer impact. In this paper, we proposed a portable device for the non-destructive evaluation of rock bolt conditions based on a giant magnetostrictive (GMS) actuator. The GMS actuator generates enough energy to ensure multiple reflections of the stress waves along the rock bolt and a lead zirconate titantate (PZT) sensor is used to detect the reflected waves. A new integrated procedure that involves correlation analysis, wavelet denoising, and Hilbert transform was proposed to process the multiple reflection signals to determine the length of an installed rock bolt. The experimental results from a lab test and field tests showed that, by analyzing the instant phase of the periodic reflections of the stress wave generated by the GMS transducer, the length of an embedded rock bolt can be accurately determined.

  9. Behaviour of high stretch bolts in tension working as part of elements of steel structures, and their tendency to delayed fracturing

    Directory of Open Access Journals (Sweden)

    Moyseychik Evgeniy Alekseevich

    2014-12-01

    Full Text Available In the article, the author has proven that manufacturing and installation errors, as well as contact deformations of high strength bolts, if analyzed as part of tensile connections of steel structures, work in eccentric tension. In pursuance of the effective state standards, the analysis of these bolts is based on the axial tension. The author has analyzed the failure of a steel structure, caused by the fracture of eccentrically loaded bolts made of steel grade XC 42 (France, or C40 (Germany, that later followed the delayed fracturing pattern. The author provides the findings of the lab tests, whereby the above bolts were tested in the presence of an angle washer. The author has also analyzed the findings of low-temperature tests of bolts in tension. The author demonstrates that the strength of high strength bolts is driven by the material, the structure shape, and the thermal treatment pattern. Eccentric tension tests of bolts have proven that cracks emerge in the areas of maximal concentration of stresses (holes in shafts, etc. that coincide with the areas where fibers are in tension; cracks tend to follow the delayed fracturing pattern, and their development is accompanied by the deformation-induced metal heating in the fracture area. Therefore, the analysis of high strength bolts shall concentrate on the eccentric tension with account for contact-induced loads, while the tendency to delayed fracturing may be adjusted through the employment of both metallurgical and process techniques.

  10. DIGITAL DIVIDE IN THE EUROPEAN UNION

    Directory of Open Access Journals (Sweden)

    Radu HERMAN

    2009-10-01

    Full Text Available This paper aims to demonstrate that income, education and infrastructure play a critical role in shaping the divide. The global challenge for the new millennium is to build a society where everyone can access and shareinformation. A fully integrated digital world has become a reality, and all segments of society must embrace it in order to be contributing partners to future success in the EU. As they are fast becoming an essential tool for economic activity, Information and Communication Technologies (ICT became a vital engine of economic performance. The problem, however, is that in many countries technological diffusion is obstructed by the limited capacity of networks to carry large amounts of knowledge swiftly and the limited access of individuals even to networks in which knowledge products are minimal.

  11. Library outreach: addressing Utah's "Digital Divide".

    Science.gov (United States)

    McCloskey, K M

    2000-10-01

    A "Digital Divide" in information and technological literacy exists in Utah between small hospitals and clinics in rural areas and the larger health care institutions in the major urban area of the state. The goals of the outreach program of the Spencer S. Eccles Health Sciences Library at the University of Utah address solutions to this disparity in partnership with the National Network of Libraries of Medicine-- Midcontinental Region, the Utah Department of Health, and the Utah Area Health Education Centers. In a circuit-rider approach, an outreach librarian offers classes and demonstrations throughout the state that teach information-access skills to health professionals. Provision of traditional library services to unaffiliated health professionals is integrated into the library's daily workload as a component of the outreach program. The paper describes the history, methodology, administration, funding, impact, and results of the program.

  12. Test and application of hydraulic expansion bolts in a roadway under goaf with ultra-close separation

    Institute of Scientific and Technical Information of China (English)

    Wang Xiangyu; Bai Jianbiao; Guo Guanlong; Yu Yang

    2014-01-01

    The roof of a roadway under goaf with ultra-close separation consists of thin rock strata and rocks caving in upper goaf. Influenced by the mining of the upper coal seam, the roof is loose and broken, and its integ-rity is poor. Resin anchored bolts cannot provide an effective anchoring force in such roof conditions. By conducting free expansion tests and field pull-out tests on a hydraulic expansion bolt, this study has ana-lyzed the influencing factors and laws of radial expansion and anchoring force changes in the rod body. This has revealed the anchoring mechanism of such bolts, and has obtained reasonable water injection pressures and suitable drilling diameters (which are 20–25 MPa and 32–35 mm respectively) for the hydraulic expansion bolt (u28 mm) used in these tests. Based on pull-out tests at different interlayer spacing, the applicability of hydraulic expansion bolts had been verified for controlling the roof of road-ways under goaf with ultra-close distance. Combined with the deformation and failure characteristics of the test roadway roof, this paper proposes a united roof-control technology based on the use of hydraulic expansion bolts and advancing intubation for the roof. Engineering practice indicated that the roof of the test roadway did not generate leaking and caving phenomenon, and the amount of roof deformation was controlled to within 150 mm. Maintenance of the roadway roof has been improved significantly, which ensures safe mining in coal seams with ultra-close separation.

  13. Mechanism and technology study of collaborative support with long and short bolts in large-deformation roadways

    Institute of Scientific and Technical Information of China (English)

    Yu Hui⇑; Niu Zhiyong; Kong Linggen; Hao Caicheng; Cao Peng

    2015-01-01

    Common short bolts of equal length are widely used to support the roofs of roadways in coal mines. However, they are insufficient to keep the roof stable against large deformations, so docking long bolts with high levels of elongation that can adapt to large deformations of the surrounding rock have been adopted. This paper proposes a collaborative support method that uses long and short bolts. In this study, the mechanism of docking long bolts and collaborative support was studied. Numerical simulation, sim-ilarity simulation, and field testing were used to analyze the distribution law of the displacement, stress, and plastic failure in the surrounding rock under different support schemes. Compared with the equal-length short bolt support, the collaborative support changed the maximum principal stress of the shallow roof from tensile stress to compressive stress, and the minimum principal stress of the roof significantly increased. The stress concentration degree of the anchorage zone clearly increased. The deformation of the roof and the two sides was greatly reduced, and the subsidence shape of the shallow roof changed from serrated to a smooth curve. The roof integrity was enhanced, and the roof moved down as a whole. Plastic failure significantly decreased, and the plastic zone of the roof was within the anchorage range. The similarity simulation results showed that, under the maximum mining stress, the roof collapsed with the equal-length short bolt support but remained stable with the collaborative support. The collaborative support method was successfully applied in the field and clearly improved the stability of the surrounding rock for a large deformation roadway.

  14. Angular shear plate

    Science.gov (United States)

    Ruda, Mitchell C [Tucson, AZ; Greynolds, Alan W [Tucson, AZ; Stuhlinger, Tilman W [Tucson, AZ

    2009-07-14

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

  15. STATISTICAL ENTROPIES OF THE TAUB-NUT/BOLT AdS SPACES FROM THE HORIZON CONFORMAL FIELD THEORY

    Institute of Scientific and Technical Information of China (English)

    JING JI-LIANG; ZHOU SAN-QING; HUANG YI-BIN

    2001-01-01

    The covariant phase technique is used to compute the constraint algebra of the four-dimensional space-times which are asymptotic to anti-de Sitter (AdS), such as the planar Taub-NUT AdS and Taub-bolt AdS spaces, and the hyperbolic Taub-bolt AdS space. The standard Virasoro subalgebrae with corresponding central charges for these objects are constructed and the resulting densities of states yield the expected Bekenstein-Hawking entropies.

  16. High-strength bolt-forming of fine-grained aluminum alloy 6061 with a continuous hybrid process

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Hun; Hwang, Sun Kwang [National Research Laboratory for Computer Aided Materials Processing, Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Im, Yong-Taek, E-mail: ytim@kaist.ac.kr [National Research Laboratory for Computer Aided Materials Processing, Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Son, Il-Heon; Bae, Chul Min [Wire Rod Research Group, Technical Research Laboratories, POSCO, 1 Goedong-dong, Nam-gu, Pohang, Gyeongbuk 790-785 (Korea, Republic of)

    2012-08-30

    Highlights: Black-Right-Pointing-Pointer Fine-grained AA6061-O was produced by a continuous hybrid process. Black-Right-Pointing-Pointer It consists of rolling, ECAP, and drawing. Black-Right-Pointing-Pointer High-strength bolt was manufactured with the fine-grained AA6061-O. Black-Right-Pointing-Pointer The UTS and micro-hardness of the bolt was increased by 50%. Black-Right-Pointing-Pointer The route C was better in making a uniform micro-hardness distribution in the bolt. - Abstract: It is well known that the development of a continuous manufacturing process to apply severe plastic deformation (SPD) is a major challenge for industrial usages to improve the mechanical properties of the material through grain refinement. In this study, fine-grained AA6061-O wire was manufactured by a two-pass hybrid process consisting of drawing, equal channel angular pressing and rolling in a continuous manner to investigate the effects of processing routes for two different routes, A and C, on the variation of ultimate tensile strength (UTS) and micro-hardness distribution. The UTS value (185 MPa) of the specimen processed by the two-pass hybrid process with route A was higher than that of 171 MPa obtained from the two-pass wire-drawing process and was equivalent to the level of 184 MPa processed by the three-pass wire-drawing process. The average micro-hardness value (Hv 58.0) obtained from the two-pass hybrid process through route C was the highest among all the cases. According to transmission electron microscopy, the original grain was subdivided and elongated owing to deformation during the processes. The specimen processed by the two-pass hybrid process through route C showed smaller deformation bands and had potentially higher angle grain boundaries compared to the specimen processed by the two-pass wire-drawing process. Finally, the high-strength bolt was manufactured using the fine-grained AA6061-O wire prepared by the continuous hybrid process to check its formability

  17. Research on a New Type of Diamond Saw Plate

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With the developing of stone material, diamond saw pl ate is used widely, and in order to increase cutting efficiency and life-span o f diamond saw plate, there are a lot of research jobs of segment for diamond saw plate. Layered segment for diamond saw plate is to divide single segment into s everal cutting tools by its structure, then increases rock-cutting faces. For i mpregnated man-made diamond saw plate, the bonding strength of diamonds with ma trix material has great effect on its life and service....

  18. A Detailed Analysis of the BR1 Locus Suggests a New Mechanism for Bolting after Winter in Sugar Beet (Beta vulgaris L.).

    Science.gov (United States)

    Tränkner, Conny; Lemnian, Ioana M; Emrani, Nazgol; Pfeiffer, Nina; Tiwari, Surya P; Kopisch-Obuch, Friedrich J; Vogt, Sebastian H; Müller, Andreas E; Schilhabel, Markus; Jung, Christian; Grosse, Ivo

    2016-01-01

    Sugar beet (Beta vulgaris ssp. vulgaris) is a biennial, sucrose-storing plant, which is mainly cultivated as a spring crop and harvested in the vegetative stage before winter. For increasing beet yield, over-winter cultivation would be advantageous. However, bolting is induced after winter and drastically reduces yield. Thus, post-winter bolting control is essential for winter beet cultivation. To identify genetic factors controlling bolting after winter, a F2 population was previously developed by crossing the sugar beet accessions BETA 1773 with reduced bolting tendency and 93161P with complete bolting after winter. For a mapping-by-sequencing analysis, pools of 26 bolting-resistant and 297 bolting F2 plants were used. Thereby, a single continuous homozygous region of 103 kb was co-localized to the previously published BR1 QTL for post-winter bolting resistance (Pfeiffer et al., 2014). The BR1 locus was narrowed down to 11 candidate genes from which a homolog of the Arabidopsis CLEAVAGE AND POLYADENYLATION SPECIFICITY FACTOR 73-I (CPSF73-I) was identified as the most promising candidate. A 2 bp deletion within the BETA 1773 allele of BvCPSF73-Ia results in a truncated protein. However, the null allele of BvCPSF73-Ia might partially be compensated by a second BvCPSF73-Ib gene. This gene is located 954 bp upstream of BvCPSF73-Ia and could be responsible for the incomplete penetrance of the post-winter bolting resistance allele of BETA 1773. This result is an important milestone for breeding winter beets with complete bolting resistance after winter.

  19. Entry roof truss-bolt system test under the gob of contiguous seams

    Institute of Scientific and Technical Information of China (English)

    LIAN Chuan-jie; XU Wei-ya; WANG Ya-jie

    2007-01-01

    Roof bolt support system has been widely applied in the No.7.9 seam in Caozhuang coal mine.However,it has not been able to be applied in the NO.10-2 seam since the small interburden(2m)between NO.9 and NO.10-2 seam.The NO.9 and NO.10-2 seams are contiguous seams.The NO.9 seam has been mined out and the NO.10-2 seam will be mined under the gob of the NO.9 seam.The roof strata of the NO.10-2 seam may have been weakened and fractured due to the shear failure caused by the NO.9 seam mining activities.The steel beam sets spaced at 0.8 m have been used to support the entry of the NO.10-2 seam.In order to speed up the advance rate and cut entry development cost,a test area,using roof bolt in conjunction with truss-system,was successfully conducted.This paper presents the support system design,application of designed system,and the test results.Test results provide a cheaper,quicker,and safer way to support entry for the No.10-2 seam.

  20. Professor Usain Bolt Welcomes You to the Schoolyard: Physics for Champions

    Science.gov (United States)

    Vourlias, Kostas; Seroglou, Fanny

    2016-01-01

    Could Usain Bolt achieve what teachers often fail to do? Could this famous Olympic winner challenge and motivate students to study mechanics and introduce them to the principles of physics in a fun way, outside of the classroom? In order to answer these questions, we "invited" for one semester the world record holder to visit our Greek high school in Thessaloniki as a guest teacher. For 13 weeks, 27 fifteen-year-olds run (or at least try to run) side by side with this great athlete, intending to learn his secrets. Within 9.58 s or 100 m, students have the chance to study a "phenomenon" of their daily lives and be introduced to a variety of concepts of physics in a pleasant and effective way. Students use simple athletic and innovative biomechanical equipment for their experiments, but mostly their own bodies, as experimental tools in order to study and to "feel" physics. Students have the chance to compare their athletic abilities to Bolt's and confront some of their ideas concerning concepts of physics.

  1. A Noble Approach of Process Automation in Galvanized Nut, Bolt Manufacturing Industry

    Directory of Open Access Journals (Sweden)

    Akash Samanta

    2012-05-01

    Full Text Available Corrosion costs money”, The Columbus battle institute estimates that corrosion costs Americans more than $ 220 billion annually, about 4.3% of the gross natural product [1].Now a days due to increase of pollution, the rate of corrosion is also increasing day-by-day mainly in India, so, to save the steel structures, galvanizing is the best and the simplest solution. Due to this reason galvanizing industries are increasing day-by-day since mid of 1700s.Galvanizing is a controlled metallurgical combination of zinc and steel that can provide a corrosion resistance in a wide variety of environment. In fact, the galvanized metal corrosion resistance factor can be some 70 to 80 times greater that the base metal material. Keeping in mind the importance of this industry, a noble approach of process automation in galvanized nut-bolt  manufacturing plant is presented here as nuts and bolts are the prime ingredient of any structure. In this paper the main objectives of any industry like survival, profit maximization, profit satisfying and sales growth are fulfilled. Furthermore the environmental aspects i.e. pollution control and energy saving are also considered in this paper. The whole automation process is done using programmable logic controller (PLC which has number of unique advantages like being faster, reliable, requires less maintenance and reprogrammable. The whole system has been designed and tested using GE, FANUC PLC.

  2. Estimation of the Axial Stress in High-Tension Bolt by Acoustoelastic Method

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Hae Hwa; Lee, Tae Hoon; Jhang, Kyung Young [Hanyang University, Seoul (Korea, Republic of); Kim, Noh Yu [Korea University of Technology and Education, Cheonan (Korea, Republic of)

    2006-10-15

    The evaluation of clamping condition has been regarded as the main issue in the safety-maintenance of the clamped high-tension bolts. For this, this paper proposes a method to estimate the axial stress by measuring the Tofu (Time-Of-Flight) of ultrasonic wave, which is based on the acetylsalicylate or the dependency of sound speed on the stress. In this method, however, the variation of sound speed within the range of stress induced under the field condition is very small, and thus the accuracy of the Tofu measurement is important. We adopted the phase detection method using tone-burst ultrasonic wave to measure the precise Tofu. In order to verify the usefulness of the proposed method experiments are carried out and the results were compared with the stress measured by the strain gage. The results show good agreement with each other, and from these we can conclude that the proposed method is highly useful fnr the evaluation of clamping condition in the clamped high-tension bolts

  3. The Extended Thermodynamic Properties of a topological Taub-NUT/Bolt-AdS spaces

    CERN Document Server

    Lee, Chong Oh

    2015-01-01

    We consider the extended thermodynamic quantities of higher dimensional topological Taub-NUT/Bolt-AdS black holes with a cosmological constant treated as a pressure and find their general form for arbitrary dimensions and the thermodynamics of these configurations is argued to some extent. In particular by introducing Gibbs free energy, it is found out to be a new thermodynamically stable region of these black holes. At an equilibrium condition we find an entropy of a NUT solution, volume, and latent heat are negative where the Clapeyron equation is satisfied for these thermodynamic quantities. These negative volume and entropy may be interpreted as that the environment applies work to the system in the process of the Taub-NUT-AdS black hole formation, and such negative latent heat may indicate a net release of latent energy back into the environment because of evaporating of the system. Intriguingly, we also find that like the AdS black hole case, Taub-Bolt-AdS black hole with two phases (phase of small and ...

  4. Bridging the divide between science and journalism.

    Science.gov (United States)

    Van Eperen, Laura; Marincola, Francesco M; Strohm, Jennifer

    2010-03-10

    There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media.Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings.

  5. New Frontiers in the Digital Divide

    DEFF Research Database (Denmark)

    Jæger, Birgit

    In a new strategy for e-government, the Danish government set the goal that in 2015 all contacts between citizens and public authorities must be conducted electronically. In accordance with EU’s strategy for e-government every citizen ought to have equal access to public services, hence the quest......In a new strategy for e-government, the Danish government set the goal that in 2015 all contacts between citizens and public authorities must be conducted electronically. In accordance with EU’s strategy for e-government every citizen ought to have equal access to public services, hence...... for digital inclusion becomes a central theme for the implementation of the new e-government strategy. Until now it has been voluntary whether or not citizens want to use ICT and a lot of especially senior citizens have chosen not to use the technology. However, senior citizens are not the only group affected...... of the e-government strategy. New frontiers in the digital divide are opening and a new group of excluded become visible: the youngsters. In this way, one of the leading Danish newspapers reports that young people lines up in town halls to get help to fill out forms, which are already available...

  6. The Digital Divide and urban older adults.

    Science.gov (United States)

    Cresci, M Kay; Yarandi, Hossein N; Morrell, Roger W

    2010-01-01

    Computers and the Internet offer older adults opportunities and resources for independent living. However, many urban older adults do not use computers. This study examined the demographic, health, and social activities of urban older adults to determine variables that might predict the use and nonuse of computers in this population. A secondary data analysis was performed using the 2001 Detroit City-Wide Needs Assessment of Older Adults (n = 1410) data set. Logistic regression was used to explore potential differences in predictor variables between computer users and nonusers. Overall, computer users were younger (27%), had a higher level of education, were more likely to be employed, had an annual income greater than $20,000, and were healthier and more active than nonusers. They also were more likely to have memberships in community organizations and do volunteer work. Preferred computer activities included conducting Internet searches, playing games, writing, and communicating with family members and friends. The results suggest significant differences in demographic and health-related characteristics between computer users and nonusers among urban older adults. Although about a quarter of participants in this study used computers, the Digital Divide continues to exist in urban settings for scores of others.

  7. Bridging the digital divide: reaching vulnerable populations.

    Science.gov (United States)

    Chang, Betty L; Bakken, Suzanne; Brown, S Scott; Houston, Thomas K; Kreps, Gary L; Kukafka, Rita; Safran, Charles; Stavri, P Zoe

    2004-01-01

    The AMIA 2003 Spring Congress entitled "Bridging the Digital Divide: Informatics and Vulnerable Populations" convened 178 experts including medical informaticians, health care professionals, government leaders, policy makers, researchers, health care industry leaders, consumer advocates, and others specializing in health care provision to underserved populations. The primary objective of this working congress was to develop a framework for a national agenda in information and communication technology to enhance the health and health care of underserved populations. Discussions during four tracks addressed issues and trends in information and communication technologies for underserved populations, strategies learned from successful programs, evaluation methodologies for measuring the impact of informatics, and dissemination of information for replication of successful programs. Each track addressed current status, ideal state, barriers, strategies, and recommendations. Recommendations of the breakout sessions were summarized under the overarching themes of Policy, Funding, Research, and Education and Training. The general recommendations emphasized four key themes: revision in payment and reimbursement policies, integration of health care standards, partnerships as the key to success, and broad dissemination of findings including specific feedback to target populations and other key stakeholders.

  8. The Gender Digital Divide in Developing Countries

    Directory of Open Access Journals (Sweden)

    Amy Antonio

    2014-10-01

    Full Text Available Empirical studies clearly show that women in the developing world have significantly lower technology participation rates than men; a result of entrenched socio-cultural attitudes about the role of women in society. However, as studies are beginning to show, when those women are able to engage with Internet technology, a wide range of personal, family and community benefits become possible. The key to these benefits is on-line education, the access to which sets up a positive feedback loop. This review gives an overview of the digital divide, before focusing specifically on the challenges women in developing countries face in accessing the Internet. Current gender disparities in Internet use will be outlined and the barriers that potentially hinder women’s access and participation in the online world will be considered. We will then look at the potential opportunities for women’s participation in a global digital society along with a consideration of current initiatives that have been developed to mitigate gender inequity in developing countries. We will also consider a promising avenue for future research.

  9. Quantitative Measurement of the Digital Divide

    Science.gov (United States)

    Cottrell, Roger

    2007-04-01

    Bandwidth and the Internet infrastructure are the life-blood of the world's knowledge economy, but they are often scarcest where most needed. Measuring the numbers of users of the Internet infrastructure is not easy in developing countries because many people share accounts, use corporate and academic networks, or visit the rapidly growing number of cyber cafes, telecentres and business services. Also measuring the number of users does not take into account the level of use. One valuable indicator for measuring the Internet infrastructure is the international Internet performance of a country or region. One of the major aims of the PingER project is to provide an historical archive of extensive, publicly accessible, up-to-date, measurements, analyses and reports of multiple Internet performance indicators (such as delay, loss, throughput, reachability, and jitter) between sites, countries and regions of the world. This talk will briefly describe the PingER project and then compare and contrast the Internet performance and its trends within and between countries and regions of the world. By means of extensive case studies it will also identify which regions need the greatest attention, together with their major issues and possible approaches to reducing the divide.

  10. Vegetation baseline report : Connacher great divide project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-08-01

    This baseline report supported an application by Connacher Oil and Gas Ltd. to the Alberta Energy and Utilities Board (EUB) and Alberta Environment (AENV) for the Great Divide Steam Assisted Gravity Drainage (SAGD) Project. The goal of the report was to document the distribution and occurrence of ecosite phases and wetland classes in the project footprint as well as to document the distribution of rare plants; rare plant communities: and intrusive species and old growth communities, including species of management concern. A methodology of the baseline report was presented, including details of mapping and field surveys. Six vegetation types in addition to the disturbed land unit were identified in the project footprint and associated buffer. It was noted that all vegetation types are common for the boreal forest natural regions. Several species of management concern were identified during the spring rare plant survey, including rare bryophytes and non-native or invasive species. Mitigation was identified through a slight shift of the footprint, transplant of appropriate bryophyte species and implementation of a weed management plan. It was noted that results of future surveys for rare plants will be submitted upon completion. It was concluded that the effects of the project on existing vegetation is expected to be low because of the small footprint, prior disturbance history, available mitigation measures and conservation and reclamation planning. 27 refs., 5 tabs., 4 figs.

  11. Bridging the Divide between Science and Journalism

    Directory of Open Access Journals (Sweden)

    Marincola Francesco M

    2010-03-01

    Full Text Available Abstract There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media. Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings.

  12. Asymmetric localization of Numb:EGFP in dividing neuroepithelial cells during neurulation in Danio rerio.

    Science.gov (United States)

    Reugels, Alexander M; Boggetti, Barbara; Scheer, Nico; Campos-Ortega, José A

    2006-04-01

    In the neural plate and tube of the zebrafish embryo, cells divide with their mitotic spindles oriented parallel to the plane of the neuroepithelium, whilst in the neural keel and rod, the spindle is oriented perpendicular to it. This change is achieved by a 90 degrees rotation of the mitotic spindle. We cloned zebrafish homologues of the gene for the Drosophila cell fate determinant Numb, and analyzed the localization of EGFP fusion proteins in vivo in dividing neuroepithelial cells during neurulation. Whereas Numb isoform 3 and the related protein Numblike are localized in the cytoplasm, Numb isoform 1 is localized to the cell membrane. Time-lapse analyses showed that Numb 1 is distributed uniformly around the cell cortex in dividing cells during plate and keel stages, but becomes localized at the basolateral membrane of some dividing cells during the transition from neural rod to tube. Using in vitro mutagenesis and Numb:EGFP deletion constructs, we showed that the first 196 amino acids of Numb are sufficient for this localization. Furthermore, we found that an 11-amino acid insertion in the PTB domain is essential for localization to the cortex, whereas amino acids 2-12 mediate the basolateral localization in the neural tube stage.

  13. Benchmark for license plate character segmentation

    Science.gov (United States)

    Gonçalves, Gabriel Resende; da Silva, Sirlene Pio Gomes; Menotti, David; Shwartz, William Robson

    2016-09-01

    Automatic license plate recognition (ALPR) has been the focus of many researches in the past years. In general, ALPR is divided into the following problems: detection of on-track vehicles, license plate detection, segmentation of license plate characters, and optical character recognition (OCR). Even though commercial solutions are available for controlled acquisition conditions, e.g., the entrance of a parking lot, ALPR is still an open problem when dealing with data acquired from uncontrolled environments, such as roads and highways when relying only on imaging sensors. Due to the multiple orientations and scales of the license plates captured by the camera, a very challenging task of the ALPR is the license plate character segmentation (LPCS) step, because its effectiveness is required to be (near) optimal to achieve a high recognition rate by the OCR. To tackle the LPCS problem, this work proposes a benchmark composed of a dataset designed to focus specifically on the character segmentation step of the ALPR within an evaluation protocol. Furthermore, we propose the Jaccard-centroid coefficient, an evaluation measure more suitable than the Jaccard coefficient regarding the location of the bounding box within the ground-truth annotation. The dataset is composed of 2000 Brazilian license plates consisting of 14000 alphanumeric symbols and their corresponding bounding box annotations. We also present a straightforward approach to perform LPCS efficiently. Finally, we provide an experimental evaluation for the dataset based on five LPCS approaches and demonstrate the importance of character segmentation for achieving an accurate OCR.

  14. The ITER EC H and CD upper launcher: Design, analysis and testing of a bolted joint for the Blanket Shield Module

    Energy Technology Data Exchange (ETDEWEB)

    Gessner, Robby, E-mail: robby.gessner@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, D-76021 Karlsruhe (Germany); Aiello, Gaetano; Grossetti, Giovanni; Meier, Andreas [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, D-76021 Karlsruhe (Germany); Ronden, Dennis [DIFFER – Dutch Institute for Fundamental Energy Physics, P.O. Box 1207, NL-3430 BE Nieuwegein (Netherlands); Spaeh, Peter; Scherer, Theo; Schreck, Sabine; Strauss, Dirk; Vaccaro, Alessandro [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, D-76021 Karlsruhe (Germany)

    2013-10-15

    Highlights: ► The BSM of the ECH Launcher is attached to the Launcher Main Frame by a bolted joint. ► The bolts were designed as “captive” in order to avoid their accidental removal from the joint. ► The bolted flange connection using two sets of 15 captive bolts (M22 × 2) placed along the sides. ► The captive bolt design is based on a concept that uses a dedicated spring ring, a standard spiral spring and a tensioning screw with two threads to secure the bolts in a form-locking stop. -- Abstract: The final design of the structural system for the ITER EC H and CD upper launcher is in progress. Many design features of the preliminary design are under revision with the aim to achieve the built-to-print-status. This paper deals with design and analysis of a bolted joint for the Blanket Shield Module with special perspective on Remote Handling capability. The BSM of the ECH Launcher is attached to the Launcher Main Frame by a bolted joint conceived so that in the Hot Cell Facility, RH maintenance can be performed on internal components. The joint must be capable to resist very high Electro-Magnetic loads from disruptions, while it has to sustain substantial thermal cycling during operation. Thus the need for a rigid and reliable design is essential. Beside the set of pre-stressed bolts the flanges were therefore equipped with additional shear keys to divert radial moments away from the bolts. Main focus of the work performed was the mechanical design of the joint and the assessment of the structural integrity with respect to the loads applied and its capability for maintenance by RH procedures. To fulfill a major aspect of the RH requirements, the bolts were designed as “captive” in order to avoid their accidental removal from the joint. The captive bolt design is based on a concept that uses a dedicated spring ring, a standard spiral spring and a tensioning screw with two threads to secure the bolts in a form-locking stop. The final approval phase of

  15. Large Scale Finite Element Thermal Analysis of the Bolts of a French PWR Core Internal Baffle Structure

    Energy Technology Data Exchange (ETDEWEB)

    Rupp, Isabelle; Christophe, Peniguel [EDF R and D, Paris (France); Tommy, Martin Michel [1 av du General de Gaulle, Paris (France)

    2009-11-15

    The internal core baffle structure of a French Pressurized Water Reactor (PWR) consists of a collection of baffles and formers that are attached to the barrel. The connections are done thanks to a large number of bolts (about 1500). After inspection, some of the bolts have been found cracked. This has been attributed to the Irradiation Assisted Stress Corrosion Cracking (IASCC). The Electricite De France (EDF) has set up a research program to gain better knowledge of the temperature distribution, which may affect the bolts and the whole structure. The temperature distribution in the structure was calculated thanks to the thermal code SYRTHES that used a finite element approach. The heat transfer between the by-pass flow inside the cavities of the core baffle and the structure was accounted for thanks to a strong thermal coupling between the thermal code SYRTHES and the CFD code named Code{sub S}aturne. The results for the CP0 plant design show that both the high temperature and strong temperature gradients could potentially induce mechanical stresses. The CPY design, where each bolt is individually cooled, had led to a reduction of temperatures inside the structures. A new parallel version of SYRTHES, for calculations on very large meshes and based on MPI, has been developed. A demonstration test on the complete structure that has led to about 1.1 billion linear tetraedra has been calculated on 2048 processors of the EDF Blue Gene computer

  16. Generalized Fibonacci zone plates

    CERN Document Server

    Ke, Jie; Zhu, Jianqiang

    2015-01-01

    We propose a family of zone plates which are produced by the generalized Fibonacci sequences and their axial focusing properties are analyzed in detail. Compared with traditional Fresnel zone plates, the generalized Fibonacci zone plates present two axial foci with equal intensity. Besides, we propose an approach to adjust the axial locations of the two foci by means of different optical path difference, and further give the deterministic ratio of the two focal distances which attributes to their own generalized Fibonacci sequences. The generalized Fibonacci zone plates may allow for new applications in micro and nanophotonics.

  17. "Enlivening and - Dividing": An Aporia of Illumination

    Directory of Open Access Journals (Sweden)

    Hans Christian Hönes

    2015-08-01

    Full Text Available Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Verdana;} In 1798, Karl August Böttiger paid a nocturnal visit to the Gallery of Antiques in Dresden, illuminating the statues with a torch. At first glance, this seems to be yet another example of a popular practice for visiting galleries c.1800. Illuminating the sculptures by torchlight was a popular means of enlivening the objects, set in motion by the light flickering on their surfaces. The collections were thus meant to become a place where cold, white stone comes to life, and where the beholder becomes part of a revived antiquity.This was precisely what Böttiger intended, too. But to him, the effect of the torchlight appeared to be, as he wrote, “enlivening and – dividing!” The torchlight highlighted not only the beauty of the sculptures but also their modern restorations. Böttiger apparently failed to experience the living presence of the antique celebrated by many of his contemporaries (e.g. Goethe, Moritz.This essay focuses on the consequence of such a perception of sculptures as historically multi-layered objects. Böttiger’s experience resulted in a problematic situation. In trying to view the sculptures as contemporaries, he hoped to become ancient himself. But this operation failed in the moment when the sculptures themselves appeared to be anachronistic, impure palimpsests. In consequence, galleries may not only be the place were art history as chronological Stilgeschichte was born. They may also be the site where this perception changed into the experience of a more chaotic shape of time.

  18. Inflatable rock bolt bond strength versus rock mass rating (RMR):A comparative analysis of pull-out testing data from underground mines in Nevada

    Institute of Scientific and Technical Information of China (English)

    Barnard Chase; Kallu Raj R.; Warren Sean; Thareja Rahul

    2016-01-01

    The purpose of this paper is to establish confidence in anticipated minimum bond strength for inflatable rock bolts by comparing the bond strength to variable geotechnical conditions using the rock mass rating (RMR) system. To investigate a correlation between these parameters, the minimum bond strength of pull-out tested inflatable rock bolts was compared to the RMR of the rock in which these bolts were placed. Bond strength vs. RMR plots indicate that expected minimum bond strength is positively corre-lated with RMR;however, the correlation is not strong. Cumulative percent graphs indicate that 97%of pull-out tests result in a minimum bond strength of 3.3 and 1.7 ton/m in RMR P 45 and<45, respectively. Although lower bond strengths are more commonly encountered in low RMR ground, high bond strengths are possible as well, yielding higher variability in bond strengths in low RMR ground. Bond strength of friction bolts relies on contact between the rock bolt and drill hole. Experience in Nevada indicates that RMR is known to affect both the quality and consistency of drill holes which likely affects bond strength. Drilling and bolting in low RMR ground is more sensitive to drilling and bolting practices, and strategies for maximizing bond strength in these conditions are discussed.

  19. BOLTS: a BiOphysical Larval Tracking System for Measuring Dispersal Characteristics and Marine Population Connectivity

    Science.gov (United States)

    Paris, C. B.; Srinivasan, A.; Kourafalou, V.; Sponaugle, S.; Cowen, R. K.

    2008-12-01

    While metapopulation research with hypothetical dispersal matrices has shown how the scales of larval dispersal, transport processes, local recruitment, and temporal and spatial variability in dispersal influence population persistence, the pattern of demographic connectivity produced by larval dispersal is still a key uncertainty. To address this problem, a coupled bio-physical model has been developed that quantifies the degree of connectivity between populations. Such spatially explicit models, forced by dynamic currents coupled to a realistic seascape and life history traits, produce dispersal kernels for a range of scales over which dispersal is practically unquantifiable by current empirical methods. The BiOphysical Larval Tracking System (BOLTS) presented here allows a Lagrangian stochastic individual-based model (IBM) to be coupled via OPENDAP framework to any 3-dimensional fields of circulation models including to domains of various resolutions through 'Lagrangian nesting'. We demonstrate the capabilities of the software in measuring the characteristics of dispersal and evaluating the variability of larval connectivity through two examples at different scales: 1) Caribbean-scale simulations of BOLTS using the large scale (resolution ~7 km) Hybrid Coordinate Ocean Model (HYCOM) from the Global Data Assimilative Experiment (GODAE) provide us with expected connectivity patterns of a reef building coral. By seeding the model with a large number of active particles, it is possible to assemble dispersal kernels and migration matrices from the start (spawning) and the end point (settlement) of individual particle trajectories. Any single run is a stochastic realization of a probabilistic process, thus the full probability density function (pdf) of the kernel requires averaging over many dispersal events. The model output is further corroborated with empirical measures of gene flow among coral colonies around the Caribbean. 2) Coastal-scale simulations of BOLTS

  20. Numerical study of rock bolting parameter variation effect on stability of stratified, composite roof structure of drift in a coal mine

    Institute of Scientific and Technical Information of China (English)

    LU Ting-kan; LIU Yu-zhou

    2005-01-01

    Described the outcomes of a comprehensive numerical modeling on the rock bolting performance for preventing the deformation of stratified, composite roof structure of drift in a coal mine. The investigation was undertaken in the adverse geological conditions, with variation of belt parameters, including length, density, distribution, pretension,as well as the geometry of opening, so as to determine the effect of bolting parameter variation on roof deformation and stability. The outcomes clearly demonstrated that a significant improvement of roof stability can be achieved associating with bolting parameters optimization, and indicated the importance of flexible geotechnical designation of rock mbolting reinforcement in mining practice.

  1. Thermal Shock Effects Modeling On A Globe Valve Body-Bonnet Bolted Flange Joint

    CERN Document Server

    Mathieu, Jean-Philippe; Ferrari, Jerome; Hersant, David

    2012-01-01

    This paper attends to show efforts made at EDF R&D to improve comprehension of valve parts loadings during operation. Thermal shock in a globe valve is represented and modeled using EDF R&D Finite Element Analysis code (Code_Aster). Choices of modeling are discussed and balanced on the basis of "what an engineer can obtain without becoming a researcher". First simulation results are presented. Attention is focused on the evolution of Body-Bonnet Bolted Flange Joint (BBBFJ) tightening forces which are simulated during the thermal shock. An experimental setup is also presented for the studied valve, which implies thermocouple implementation for comparison of the simulated thermal field and strain measurement on each threaded rod to validate the mechanical modeling.

  2. INJECTION MOLDING AND STRUCTURAL ANALYSIS IN METAL TO PLASTIC CONVERSION OF BOLTED FLANGE JOINT BY CAE

    Directory of Open Access Journals (Sweden)

    Marian Blaško

    2014-12-01

    Full Text Available Many metal parts in various applications are being replaced by plastic parts. There are several reasons for that depending on actual application - minimize part cost, enhance corrosion resistance, integrating more components into one part etc. Most important steps of metal to plastic conversion are material selection and design of plastic part. Plastic part has to withstand the same load as metal part. To fulfill this requirement fiber reinforced engineering plastics are often used. Also it is convenient to substitute heavy wall sections with ribbed structure to increase load-carrying ability of part and decrease cycle time, eliminate voids, sink marks etc. Mechanical properties of such part could be highly affected by fiber orientation. Results of fiber orientation from injection molding filling analysis can be used in stress analysis for better prediction of part response to mechanical load. Such coupled analysis is performed here in this case study on bolted flange joint.

  3. Failure analysis of bolted joints in foam-core sandwich composites

    DEFF Research Database (Denmark)

    Zabihpoor, M.; Moslemian, Ramin; Afshin, M.

    2008-01-01

    This study represents an effort to predict the bearing strength, failure modes, and failure load of bolted joints in foam-core sandwich composites. The studied joints have been used in a light full composite airplane. By using solid laminates, a new design for the joint zone is developed....... These solid laminates include a number of glass plies with total thickness equal to core thickness. The effect of solid laminate size and interface angle of foam -solid laminate in the bonding zone on the bearing strength, failure loads and type of modes are investigated. The numerical study is performed...... using 3D FEM in ANSYS commercial code. Tsai-Wu failure criterion is used in the failure analysis. The results indicate that the most important parameter in the proposed joint zone design is the foam -solid laminate interface angle which plays an important role on the value of failure criterion (damage...

  4. Thermodynamic volumes for AdS-Taub-NUT and AdS-Taub-Bolt

    Science.gov (United States)

    Johnson, Clifford V.

    2014-12-01

    In theories of semi-classical quantum gravity where the cosmological constant is considered a thermodynamic variable, the gravitational mass of a black hole has been shown to correspond to the enthalpy of the thermodynamic system, rather than the energy. We propose that this should be extended to all spacetime solutions, and consider the meaning of this extension of gravitational thermodynamics for the Taub-NUT and Taub-Bolt geometries in four dimensional locally anti-de Sitter spacetime. We present formulae for their thermodynamic volumes. Surprisingly, Taub-NUT has negative volume, for which there is a natural dynamical explanation in terms of the process of formation of the spacetime. A special case corresponds to pure AdS4 with an S3 slicing. The same dynamical setting can explain the negative entropy known to exist for these solutions for a range of parameters.

  5. INFORMATION FOR USERS OF NUTS, BOLTS, SCREWS, NAILS AND RIVETS (SCEM GROUP 47)

    CERN Multimedia

    Logistics Group

    2002-01-01

    We should like to remind users that, since the closure of the self-service stores, nuts, bolts, screws, nails and rivets (Group 47 of the Stores Catalogue) can be obtained, in smaller packages than via EDH, from the 'Emergency Counter' in the Central Stores (Building 73, R-002) upon presentation of a duly completed hard-copy Materials Request form. The 'Emergency Counter' is open Mondays to Fridays from 7.30 a.m. to 11.50 a.m. and from 1.00 p.m. to 4.20 p.m. Information concerning the available packages can be found under the appropriate SCEM reference number in the Stores Catalogue. Logistics Group SPL Division

  6. 1300 MPa High Strength Steel for Bolt with Superior Delayed Fracture Resistance

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By the increase in Mo content, the addition of microalloying elements V and Nb and by reducing the contents of Mn, P and S based on the composition of steel 42CrMo, we have developed a 1300 MPa-grade high strength steel (ADF1) for bolts. The sustained load bending test, sustained load tensile test and stress corrosion cracking test have been carried out to evaluate the delayed fracture resistance of steel ADF1 and commercial steel 42CrMo. The results showed that steel ADF1 has superior delayed fracture resistance to that of 42CrMo steel. It's concluded that the superior delayed fracture resistance of ADF1 is mainly due to the increase of tempering temperature, fine homogeneously distributed MC carbide and fine prior austenite grain size.

  7. Improving the transient response of a bolt-clamped Langevin transducer using a parallel resistor.

    Science.gov (United States)

    Chang, Kuo Tsi

    2003-08-01

    This paper suggests a parallel resistor to reduce DC time constant and DC response time of the transient response, induced immediately after an AC voltage connected to a bolt-clamped Langevin transducer (BLT) is switched off. An equivalent circuit is first expressed. Then, an open-circuit transient response at the terminals induced by initial states is derived and measured, and thus parameters for losses of the BLT device are estimated by DC and AC time constants of the transient response. Moreover, a driving and measuring system is designed to determine transient response and steady-state responses of the BLT device, and a parallel resistor is connected to the BLT device to reduce the DC time constant. Experimental results indicate that the DC time constant greatly exceeds the AC time constant without the parallel resistor, and greatly decreases from 42 to 1 ms by a 100-kOmega parallel resistor.

  8. Crystalline capsules: metal-organic frameworks locked by size-matching ligand bolts.

    Science.gov (United States)

    Wang, Hao; Xu, Jian; Zhang, Da-Shuai; Chen, Qiang; Wen, Rong-Mei; Chang, Ze; Bu, Xian-He

    2015-05-11

    Metal-organic frameworks (MOFs) are shown to be good examples of a new class of crystalline porous materials for guest encapsulation. Since the encapsulation/release of guest molecules in MOF hosts is a reversible process in nature, how to prevent the leaching of guests from the open pores with minimal and nondestructive modifications of the structure is a critical issue. To address this issue, we herein propose a novel strategy of encapsulating guests by introducing size-matching organic ligands as bolts to lock the pores of the MOFs through deliberately anchoring onto the open metal sites in the pores. Our proposed strategy provides a mechanical way to prevent the leaching of guests and thereby has less dependence on the specific chemical environment of the hosts, thus making it applicable for a wide variety of existing MOFs once the size-matching ligands are employed.

  9. Blue Willow Story Plates

    Science.gov (United States)

    Fontes, Kris

    2009-01-01

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

  10. Create Your Plate

    Medline Plus

    Full Text Available ... In Memory In Honor Become a Member En Español Type 1 Type 2 About Us Online Community ... Page Text Size: A A A Listen En Español Create Your Plate Create Your Plate is a ...

  11. Create Your Plate

    Medline Plus

    Full Text Available ... Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal Planning ... Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets ...

  12. 芥蓝菜薹不同节间芥子油苷组分及含量分析%Composition and content of glucosinolates in different sections of bolting stems of Chinese kale

    Institute of Scientific and Technical Information of China (English)

    腊贵晓; 刘国顺; 杨俞娟

    2011-01-01

    The composition and content of glucosinolates ( GSs) in different bolting stem sections ( Bol-ting stem was divided into four sections from the bottom to top) of three Chinese kale ( Brassica albo-glabra L. ) cultivars (CH, CHCT and QNYQ) were analyzed by HPLC and identified by LC-MS. E-leven kinds of GSs were identified including seven aliphatic GSs ( glucoiberin, progoitrin, sinigrin, glucoraphanin, glucoalyssin, gluconapin and glucoerucin) and four indolyl GSs (4-hydroxyglucobrassi-cin, glucobrassicin, 4-methoxyglucobrassicin and neoglucobrassincin) , except for that in QNYQ, there was no glucoerucin in the first section and 4-methoxyglucobrassicin in the first and second section of bolting stems identified. In the three Chinese kale cultivars, total GS content, total aliphatic GS content and total indolyl GS content were all achieved in the top section of bolting stems in Chinese kale, however, the change trend of different GS in bolting stem sections were not consistent.%采用高效液相色谱及液相色谱-质谱联用法,以芥蓝(Brassica alboglabra L.)3个品种‘中花’、‘澄海粗条,和'全年油青’为材料,对菜薹不同节间(菜薹从膨大处到顶端依次平分为4节)芥子油苷组分和含量进行了鉴定和分析.结果表明,除4-甲硫基丁基芥子油苷在全年油青菜薹的第1节中没有检测到、4-羟基-3-吲哚甲基芥子油苷在全年油青菜薹的第1节位和第2节位中没有检测到外,在3个芥蓝品种菜薹的其它节均检测到11种芥子油苷,包括7种脂肪族芥子油苷(3-甲基亚硫酰丙基芥子油苷、2-羟基-3-丁烯基芥子油苷、2-丙烯基芥子油苷、4-甲基亚硫酰丁基芥子油苷、5-甲基亚硫酰戊基芥子油苷、3-丁烯基芥子油苷和4-甲硫基丁基芥子油苷)和4种吲哚族芥子油苷(4-羟基-3-甲基吲哚芥子油苷、3-吲哚甲基芥子油苷、4-甲氧基-3-吲哚甲基芥子油苷和1-甲氧基-3-吲哚甲基芥子油苷).在3个芥蓝品种

  13. Pixelated neutron image plates

    Science.gov (United States)

    Schlapp, M.; Conrad, H.; von Seggern, H.

    2004-09-01

    Neutron image plates (NIPs) have found widespread application as neutron detectors for single-crystal and powder diffraction, small-angle scattering and tomography. After neutron exposure, the image plate can be read out by scanning with a laser. Commercially available NIPs consist of a powder mixture of BaFBr : Eu2+ and Gd2O3 dispersed in a polymer matrix and supported by a flexible polymer sheet. Since BaFBr : Eu2+ is an excellent x-ray storage phosphor, these NIPs are particularly sensitive to ggr-radiation, which is always present as a background radiation in neutron experiments. In this work we present results on NIPs consisting of KCl : Eu2+ and LiF that were fabricated into ceramic image plates in which the alkali halides act as a self-supporting matrix without the necessity for using a polymeric binder. An advantage of this type of NIP is the significantly reduced ggr-sensitivity. However, the much lower neutron absorption cross section of LiF compared with Gd2O3 demands a thicker image plate for obtaining comparable neutron absorption. The greater thickness of the NIP inevitably leads to a loss in spatial resolution of the image plate. However, this reduction in resolution can be restricted by a novel image plate concept in which a ceramic structure with square cells (referred to as a 'honeycomb') is embedded in the NIP, resulting in a pixelated image plate. In such a NIP the read-out light is confined to the particular illuminated pixel, decoupling the spatial resolution from the optical properties of the image plate material and morphology. In this work, a comparison of experimentally determined and simulated spatial resolutions of pixelated and unstructured image plates for a fixed read-out laser intensity is presented, as well as simulations of the properties of these NIPs at higher laser powers.

  14. Plate removal following orthognathic surgery.

    Science.gov (United States)

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

    2015-11-01

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

  15. Anisotropic elastic plates

    CERN Document Server

    Hwu, Chyanbin

    2010-01-01

    As structural elements, anisotropic elastic plates find wide applications in modern technology. The plates here are considered to be subjected to not only in plane load but also transverse load. In other words, both plane and plate bending problems as well as the stretching-bending coupling problems are all explained in this book. In addition to the introduction of the theory of anisotropic elasticity, several important subjects have are discussed in this book such as interfaces, cracks, holes, inclusions, contact problems, piezoelectric materials, thermoelastic problems and boundary element a

  16. Plating in Top Agar

    OpenAIRE

    sprotocols

    2014-01-01

    1. Warm plates to room temperature before use. Cold plates causes the top agar to solidify irregularly. DO not warm plates to 37° as the top agar will take forever to solidify. - Prepare top agar as the appropriate liquid medium with 0.7% agar. Keeping 100 mL bottles is convenient. For phages, use λ top agar, which is less rich and yields bigger plaques. - Melt top agar in the microwave completely. Allow the agar to boil after liquification; incompletely melted agar looks liquid, but is...

  17. BRIDGING THE DIGITAL DIVIDE: WITH SPECIAL REFERENCE TO ...

    African Journals Online (AJOL)

    This paper describes the digital divide in Africa with special reference to Nigeria ... south. This digital divide also exists within the countries of the south, between the ... enterprises (SMEs) (Ugboma, 2010) Bridging the digital divide will help to ... resources are being diverted towards meeting the challenges of the pandemic in.

  18. Mechanical properties of fasteners -- Part 7: Torsional test and minimum torques for bolts and screws with nominal diameters 1 mm to 10 mm

    CERN Document Server

    International Organization for Standardization. Geneva

    1992-01-01

    Applies to bolts and screws of property classes 8.8 to 12.9 in accordance with ISO 898-1 with thread less than M3 for which no breaking and proof loads are indicated in ISO 898-1, as well as to short bolts and screws with nominal diameters 3 mm to 10 mm which cannot be subjected to a tensile test. The minimum breaking torques are not valid for hexagon socket set screws.

  19. Create Your Plate

    Medline Plus

    Full Text Available ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ... but changes the portion sizes so you are getting larger portions of non-starchy vegetables and a ...

  20. Create Your Plate

    Medline Plus

    Full Text Available ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ... 4/Box) Taking the guesswork out of portion control has never been easier. It can be a ...

  1. Tectonic Plate Movement.

    Science.gov (United States)

    Landalf, Helen

    1998-01-01

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

  2. MyPlate

    Science.gov (United States)

    ... our stage of life, situations, preferences, access to food, culture, traditions, and the personal decisions we make over time. All your food and beverage choices count. MyPlate offers ideas and ...

  3. Create Your Plate

    Medline Plus

    Full Text Available ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ... you have an easy portion control solution that works. Last Reviewed: October 8, 2015 Last Edited: September ...

  4. Designing Assemblies Of Plates

    Science.gov (United States)

    Williams, F. W.; Kennedy, D.; Butler, R.; Aston, G.; Anderson, M. S.

    1992-01-01

    VICONOPT calculates vibrations and instabilities of assemblies of prismatic plates. Designed for efficient, accurate analysis of buckling and vibration, and for optimum design of panels of composite materials. Written in FORTRAN 77.

  5. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal Planning What Can I Eat? Making Healthy Food Choices Diabetes Superfoods Non-starchy Vegetables Grains and Starchy Vegetables ...

  6. Create Your Plate

    Medline Plus

    Full Text Available ... Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning ... serving of dairy or both as your meal plan allows. Choose healthy fats in small amounts. For ...

  7. Create Your Plate

    Medline Plus

    Full Text Available ... 1 Diabetes Get Started Safely Get And Stay Fit Types of Activity Weight Loss Assess Your Lifestyle ... manage portion control wherever you are. Now, our best-selling, sectioned to-go plate with easy-sealing ...

  8. Create Your Plate

    Medline Plus

    Full Text Available ... Plate is a simple and effective way to manage your blood glucose levels and lose weight. With ... been easier. It can be a challenge to manage portion control wherever you are. Now, our best- ...

  9. Tectonic Plate Movement.

    Science.gov (United States)

    Landalf, Helen

    1998-01-01

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

  10. Create Your Plate

    Medline Plus

    Full Text Available ... Carbohydrates Carbohydrate Counting Make Your Carbs Count Glycemic ... to manage portion control wherever you are. Now, our best-selling, sectioned to-go plate with easy-sealing ...

  11. Enhancement of tendon–bone healing via the combination of biodegradable collagen-loaded nanofibrous membranes and a three-dimensional printed bone-anchoring bolt

    Science.gov (United States)

    Chou, Ying-Chao; Yeh, Wen-Lin; Chao, Chien-Lin; Hsu, Yung-Heng; Yu, Yi-Hsun; Chen, Jan-Kan; Liu, Shih-Jung

    2016-01-01

    A composite biodegradable polymeric model was developed to enhance tendon graft healing. This model included a biodegradable polylactide (PLA) bolt as the bone anchor and a poly(D,L-lactide-co-glycolide) (PLGA) nanofibrous membrane embedded with collagen as a biomimic patch to promote tendon–bone interface integration. Degradation rate and compressive strength of the PLA bolt were measured after immersion in a buffer solution for 3 months. In vitro biochemical characteristics and the nanofibrous matrix were assessed using a water contact angle analyzer, pH meter, and tetrazolium reduction assay. In vivo efficacies of PLGA/collagen nanofibers and PLA bolts for tendon–bone healing were investigated on a rabbit bone tunnel model with histological and tendon pullout tests. The PLGA/collagen-blended nanofibrous membrane was a hydrophilic, stable, and biocompatible scaffold. The PLA bolt was durable for tendon–bone anchoring. Histology showed adequate biocompatibility of the PLA bolt on a medial cortex with progressive bone ingrowth and without tissue overreaction. PLGA nanofibers within the bone tunnel also decreased the tunnel enlargement phenomenon and enhanced tendon–bone integration. Composite polymers of the PLA bolt and PLGA/collagen nanofibrous membrane can effectively promote outcomes of tendon reconstruction in a rabbit model. The composite biodegradable polymeric system may be useful in humans for tendon reconstruction. PMID:27601901

  12. Identification of bolting-related microRNAs and their targets reveals complex miRNA-mediated flowering-time regulatory networks in radish (Raphanus sativus L.).

    Science.gov (United States)

    Nie, Shanshan; Xu, Liang; Wang, Yan; Huang, Danqiong; Muleke, Everlyne M; Sun, Xiaochuan; Wang, Ronghua; Xie, Yang; Gong, Yiqin; Liu, Liwang

    2015-09-15

    MicroRNAs (miRNAs) play vital regulatory roles in plant growth and development. The phase transition from vegetative growth to flowering is crucial in the life cycle of plants. To date, miRNA-mediated flowering regulatory networks remain largely unexplored in radish. In this study, two small RNA libraries from radish leaves at vegetative and reproductive stages were constructed and sequenced by Solexa sequencing. A total of 94 known miRNAs representing 21 conserved and 13 non-conserved miRNA families, and 44 potential novel miRNAs, were identified from the two libraries. In addition, 42 known and 17 novel miRNAs were significantly differentially expressed and identified as bolting-related miRNAs. RT-qPCR analysis revealed that some miRNAs exhibited tissue- or developmental stage-specific expression patterns. Moreover, 154 target transcripts were identified for 50 bolting-related miRNAs, which were predominately involved in plant development, signal transduction and transcriptional regulation. Based on the characterization of bolting-related miRNAs and their target genes, a putative schematic model of miRNA-mediated bolting and flowering regulatory network was proposed. These results could provide insights into bolting and flowering regulatory networks in radish, and facilitate dissecting the molecular mechanisms underlying bolting and flowering time regulation in vegetable crops.

  13. Origami - Folded Plate Structures

    OpenAIRE

    Buri, Hans Ulrich

    2010-01-01

    This research investigates new methods of designing folded plate structures that can be built with cross-laminated timber panels. Folded plate structures are attractive to both architects and engineers for their structural, spatial, and plastic qualities. Thin surfaces can be stiffened by a series of folds, and thus not only cover space, but also act as load bearing elements. The variation of light and shadow along the folded faces emphasizes the plas...

  14. Fractal multifiber microchannel plates

    Science.gov (United States)

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

    1992-01-01

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

  15. Digital divide in education : a shift to ethical usage

    OpenAIRE

    2014-01-01

    Under the trend of ICT implementation in education, students’ learning becomes highly reliant on ICT. A student will thus suffer in his / her learning process if he / she lacks the chance of using ICT at home. This is what a divide in student’s learning is. As the occurrence of this divide is due to digital ICT devices and its effect is focussed on students’ academic performance, such divide is termed as digital divide in education (DDE). To bridge this divide, most governments around the wor...

  16. History of rock bolts and the sprayed concrete lining method. Part II. Milestones up to the 1960s

    Energy Technology Data Exchange (ETDEWEB)

    Kovari, K. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    2004-07-01

    In this part, first the origin and development of rock anchors are described. Their history began with a patent application in 1913 in Germany. The breakthrough in application came, however, only in the 1940s from the American mining industry. The first application of systematic rock bolting in a tunnel was the diversion tunnel for the Keyhole Dam in the USA in 1950. The paper describes numerous examples of civil engineering work world-wide with early application of rock bolting. It is shown how the combined application of the new support elements - steel arch, sprayed concrete and anchors has lead to the sprayed concrete lining method in the 1950s. In concluding, it is demonstrated that the so called ''New Austrian Tunnelling Method'' (NATM), which has been propagated since 1963, is in many respects borrowed and has created much confusion amongst professional engineers by dint of its pseudo-scientific basis.

  17. What would be Usain Bolt's 100-meter sprint world record without Tyson Gay? Unintentional interpersonal synchronization between the two sprinters.

    Science.gov (United States)

    Varlet, Manuel; Richardson, Michael J

    2015-02-01

    Despite the desire of athletes to separate themselves from their competitors, to be faster or better, their performance is often influenced by those they are competing with. Here we show that the unintentional or spontaneous interpersonal synchronization of athletes' movements may partially account for such performance modifications. We examined the 100-m final of Usain Bolt in the 12th IAAF World Championship in Athletics (Berlin, 2009) in which he broke the world record, and demonstrate that Usain Bolt and Tyson Gay who ran side-by-side throughout the race spontaneously and intermittently synchronized their steps. This finding demonstrates that even the most optimized individual motor skills can be modulated by the simple presence of another individual via interpersonal coordination processes. It extends previous research by showing that the hard constraints of individual motor performance do not overwhelm the occurrence of spontaneous interpersonal synchronization and open promising new research directions for better understanding and improving athletic performance.

  18. Compound seabuckthorn oil bolt joint poly cresol son in cervical LEEP postoperative suffonylureas solution of application%复方沙棘子油栓联合聚甲酚磺溶液在宫颈LEEP术后的应用

    Institute of Scientific and Technical Information of China (English)

    徐静; 孙建新

    2011-01-01

    目的 探讨复方沙棘子油栓联合聚甲酚黄溶液在宫颈LEEP术后的临床疗效.方法 将120例阴道镜病理回报:宫颈上皮内瘤变1-2级患者随机分成治疗组及对照组,治疗组宫颈LEEP刀治疗后宫颈用聚甲酚黄溶液1:10冲洗,后给复方沙棘子油栓一枚日一次应用,对照组,宫颈LEEP刀术后未曾特殊治疗.结果 宫颈LEEP刀术后,阴道流液多,出血时间长,创面愈合时间长,复方沙棘子油栓联合聚甲酚黄溶液可减少术后阴道排液时间,缩短出血时间,促进创面愈合时间.结论 复方沙棘子油栓联合聚甲酚黄溶液在宫颈LEEP治疗过程中,效果好,疗程短,复发率低.%Objective Explore compound seabuckthom oil bolt joint sons gather cresol yellow solution in cervical LEEP postoperative clinical curative effect. Methods 120 cases of vaginal mirror pathological return:cervical intraepithelial neoplasia of grade 2 variable 1-patients were randomly divided into treatment group and control group,the treatment group cervical LEEP knife after treatment cervical with polycarboxylate cresol yellow solution “flush,empress give compound seabuckthorn oil tethered to a medal,son,controls,cervix once application DaoShu LEEP after not special treatment. Results the cervix DaoShu LEEP after vaginal bleeding time,fluid flow,coagulant long long time,compound seabuckthorn oil bolt joint gather together son solution can reduce postoperative yellow cresol vaginal drainage time,reduce hemorrhage time, promote wound healing time. Conclusion compound seabuckthorn oil bolt joint gather together the son in cervical LEEP yellow cresol solution treatment process,good effect,short course,and the recurrence rate is low.

  19. 组合钢板剪力墙受剪性能分析%Shear Performance of Composite Steel Plate Shear Wall

    Institute of Scientific and Technical Information of China (English)

    廖神冰; 陈麟; 吴珊瑚; 吴轶

    2012-01-01

    改进型组合钢板剪力墙(I-CSPW)和防屈曲钢板剪力墙(BR-CSPW)均由边缘框架、钢板和与钢板用螺栓连接的混凝土板构成,但BR-CSPW在混凝土板上预留了比螺杆直径大的孔.进行了两种组合钢板剪力墙的低周反复加载试验,研究了I-CSPW和BR-CSPW在水平往复荷载作用下的破坏模式、承载力、抗侧刚度、耗能能力和延性.利用ABAQUS软件建立有限元模型,通过变化钢板和混凝土板的厚度,考察两种组合剪力墙在水平荷载作用下的承载力、抗侧刚度及混凝土损伤的差异.结果表明,随着钢板厚度增大,I-CSPW的混凝土板损伤发生时间提早,损伤程度增大.相反,钢板厚度的增大却能延迟BR-CSPW的混凝土板破坏.为抑制钢板屈曲,BR-CSPW所需的混凝土板厚度较I-CSPW小.%Two composite shear wall systems studied herein consist of steel boundary frame and steel plate with reinforced concrete plates attached to both sides by bolts. In the system called "innovative" composite shear wall (I-CSPW) the bolt hole in the concrete plate is in direct match with the bolt rod, while in the system called buckling-restrained steel plate shear wall (BR-CSPW) there is a gap in between. This paper presents the results of model tests and behavior aspects of the two composite shear walls under cyclic loading including the failure modes, strength, stiffness, energy dissipation capacity and ductility. Analytical models for the shear strength, stiffness and concrete damage of the composite walls are developed by using ABAQUS software. Results indicate that with increase in steel plate thickness the concrete plate damage decreases in BR-CSPW, while in I-CSPW, concrete plate damage occurs earlier and more seriously. Hence to restrain buckling of steel plate, thicker concrete plate should be used in I-CSPW than in BR-CSPW.

  20. 飞轮连接螺栓可靠性提升研究%Reliability Improvement Of Flywheel Connecting Bolt

    Institute of Scientific and Technical Information of China (English)

    栗明; 胡伟; 李广; 赵建永

    2016-01-01

    The flywheel and crankshaft is connected with the bolt of the flywheel,As flywheel connecting boltsis an important part of the transmission torque.If there is a problem of the flywheel connecting bolt fracture,is a great harm,it will cause the crank and the connecting parts to be declared worthless,cause serious economic losses. In order to ensure the reliability of the bolt connection,the following file will through the working condition、the influence of the EVB、driver’s driving habits、clutch matching specification、the bolts design to put forward corrective and preventive measures.%飞轮与曲轴采用飞轮连接螺栓进行联接,由于飞轮连接螺栓是传递力矩的重要部件,如果出现飞轮连接螺栓断裂的问题,危害性极大,会导致曲轴和曲轴连接件报废,造成严重的经济损失;为了确保螺栓联接的可靠性,文章从使用的工况、 EVB排气制动使用对发动机影响情况、用户驾驶习惯、离合器匹配规范、曲轴飞轮连接螺栓设计等方面提出整改预防措施。

  1. The effects of electrical stunning and percussive captive bolt stunning on meat quality of cattle processed by Turkish slaughter procedures.

    Science.gov (United States)

    Onenç, A; Kaya, A

    2004-04-01

    The effects of electrical and percussive captive bolt stunning both on initial and up to 14 days post mortem meat quality of Friesian young bulls were studied. The first group (NS; n=10) were slaughtered without stunning under Turkish slaughter procedure (these animals were slaughtered under conditions acceptable to the appropriate ethics committee) in a modern abattoir. In the second group (ES; n=10) animals were electrically stunned. In the third group (PS; n=10) animals were stunned with percussive captive bolt. Meat quality was assessed by examining muscle glycogen concentration, pH and WHC. Also cooking loss, texture parameters and consumer sensory properties were assessed at 24 h, 4, 7 and 14 days post mortem. Meat colour as L(∗), a(∗), b(∗), C(∗), h(∗) values were evaluated at 0, 48 h, 3, 5, 7, 9 and 14 days post mortem. Pre-slaughter handling affected muscle glycogen concentration (P<0.05). Animals in electrical and percussive captive bolt stunned groups had higher muscle glycogen concentrations compared to animals in the non-stunned group (P<0.05). Although pre-slaughter handling did not affect significantly pH(24 h) and WHC, differences were significant for cooking loss, colour coordinates and texture parameters at some storage times. For all sensory attributes (odour, flavour, tenderness and overall acceptability) at all ageing periods (24 h, 4, 7 and 14 days) the percussive stunned (PS) group was significantly superior to the non-stunned (NS) group. The electrically-stunned (ES) group also tended to be superior to the NS group although not all differences were statistically significant. These results indicate that percussive captive bolt stunning of cattle improved meat quality compared with cattle electrically stunned using head only tongs and those non stunned under approved Turkish slaughter procedure.

  2. Vibration and Buckling of Web Plate of the Plate Girder

    OpenAIRE

    高橋, 和雄; 呉, 明強; 中澤, 聡志; 筑紫, 宏之

    1998-01-01

    The vibration and buckling of the web of the plate girder are studied in this paper. The small deflection theory of the thin plate is used. The finite strip method is employed to solve vibration and buckling of the plate girder. Natural frequenies of buckling properties are shown for various plate girder bridges.

  3. Bending and stretching of plates

    CERN Document Server

    Mansfield, E H; Hemp, W S

    1964-01-01

    The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a

  4. Richard H. Bolt introduced me to acoustics, and I am still engaged

    Science.gov (United States)

    Dyer, Ira

    2003-04-01

    I arrived at the MIT Acoustics Laboratory in 1948, and quickly learned from Dick Bolt that U.S. submarines needed coatings to reduce vulnerability via active sonar detection. All who remember Dick will be familiar with his next step: He brought me to Robert Blizzard and A. Wilson Nolle, both then at the Lab, from whom I learned in detail how to measure and then how to understand the dynamic moduli of rubber-like materials. My path, of course, widened to include medical acoustics (under the leadership of Theodore Hueter) and scattering (Phillip Morse and Uno Ingard). Fast-forward to the present. Rubber-like materials are not only in use as submarine coatings to avoid detection by active sonars, but also to reduce noise radiated by submarines. Further, such materials cover submarine acoustic arrays to reduce flow-noise interference with signals received by such arrays. The problem that most engages me today is the stochastic nature of sound propagation in the ocean, a problem that has the practical consequence of degraded sonar performance. In the spirit of Dick, I will present snippets of my current work, with the hope of painting the big picture that he always did so well.

  5. Multi-field coupled sensing network for health monitoring of composite bolted joint

    Science.gov (United States)

    Wang, Yishou; Qing, Xinlin; Dong, Liang; Banerjee, Sourav

    2016-04-01

    Advanced fiber reinforced composite materials are becoming the main structural materials of next generation of aircraft because of their high strength and stiffness to weight ratios, and excellent designability. As key components of large composite structures, joints play important roles to ensure the integrity of the composite structures. However, it is very difficult to analyze the strength and failure modes of composite joints due to their complex nonlinear coupling factors. Therefore, there is a need to monitor, diagnose, evaluate and predict the structure state of composite joints. This paper proposes a multi-field coupled sensing network for health monitoring of composite bolted joints. Major work of this paper includes: 1) The concept of multifunctional sensor layer integrated with eddy current sensors, Rogowski coil and arrayed piezoelectric sensors; 2) Development of the process for integrating the eddy current sensor foil, Rogowski coil and piezoelectric sensor array in multifunctional sensor layer; 3) A new concept of smart composite joint with multifunctional sensing capability. The challenges for building such a structural state sensing system and some solutions to address the challenges are also discussed in the study.

  6. Nonlinear characterization of a bolted, industrial structure using a modal framework

    Science.gov (United States)

    Roettgen, Daniel R.; Allen, Matthew S.

    2017-02-01

    This article presents measurements from a sub assembly of an off-the-shelf automotive exhaust system containing a bolted-flange connection and uses a recently proposed modal framework to develop a nonlinear dynamic model for the structure. The nonlinear identification and characterization methods used are reviewed to highlight the strengths of the current approach and the areas where further development is needed. This marks the first use of these new testing and nonlinear identification tools, and the associated modal framework, on production hardware with a realistic joint and realistic torque levels. To screen the measurements for nonlinearities, we make use of a time frequency analysis routine designed for transient responses called the zeroed early-time fast Fourier transform (ZEFFT). This tool typically reveals the small frequency shifts and distortions that tend to occur near each mode that is affected by the nonlinearity. The damping in this structure is found to be significantly nonlinear and a Hilbert transform is used to characterize the damping versus amplitude behavior. A model is presented that captures these effects for each mode individually (e.g. assuming negligible nonlinear coupling between modes), treating each mode as a single degree-of-freedom oscillator with a spring and viscous damping element in parallel with a four parameter Iwan model. The parameters of this model are identified for each of the structure's modes that exhibited nonlinearity and the resulting nonlinear model is shown to capture the stiffness and damping accurately over a large range of response amplitudes.

  7. An Empirical Analysis of the Determinants of International Digital Divide

    Science.gov (United States)

    Yun, Liu

    International Digital Divide is an imbalance state of ICT penetration between countries. This paper analyzes the current status and trends of international digital divide, adopts Gompertz technology diffusion model to verify the determinants of ICT penetration level and diffusion rate separately. Finally, China should use "policy levers" to strengthen international trade cooperation, improve the capability of independent innovation, and achieve Chinese goal of bridging digital divide.

  8. Anterior cervical plating

    Directory of Open Access Journals (Sweden)

    Gonugunta V

    2005-01-01

    Full Text Available Although anterior cervical instrumentation was initially used in cervical trauma, because of obvious benefits, indications for its use have been expanded over time to degenerative cases as well as tumor and infection of the cervical spine. Along with a threefold increase in incidence of cervical fusion surgery, implant designs have evolved over the last three decades. Observation of graft subsidence and phenomenon of stress shielding led to the development of the new generation dynamic anterior cervical plating systems. Anterior cervical plating does not conclusively improve clinical outcome of the patients, but certainly enhances the efficacy of autograft and allograft fusion and lessens the rate of pseudoarthrosis and kyphosis after multilevel discectomy and fusions. A review of biomechanics, surgical technique, indications, complications and results of various anterior cervical plating systems is presented here to enable clinicians to select the appropriate construct design.

  9. Enhancement of tendon–bone healing via the combination of biodegradable collagen-loaded nanofibrous membranes and a three-dimensional printed bone-anchoring bolt

    Directory of Open Access Journals (Sweden)

    Chou YC

    2016-08-01

    Full Text Available Ying-Chao Chou,1,2 Wen-Lin Yeh,2 Chien-Lin Chao,1 Yung-Heng Hsu,1,2 Yi-Hsun Yu,1,2 Jan-Kan Chen,3 Shih-Jung Liu1,2 1Department of Mechanical Engineering, Chang Gung University, 2Department of Orthopedic Surgery, Chang Gung Memorial Hospital, 3Department of Physiology and Pharmacology, Chang Gung University, Taoyuan, Taiwan Abstract: A composite biodegradable polymeric model was developed to enhance tendon graft healing. This model included a biodegradable polylactide (PLA bolt as the bone anchor and a poly(D,L-lactide-co-glycolide (PLGA nanofibrous membrane embedded with collagen as a biomimic patch to promote tendon–bone interface integration. Degradation rate and compressive strength of the PLA bolt were measured after immersion in a buffer solution for 3 months. In vitro biochemical characteristics and the nanofibrous matrix were assessed using a water contact angle analyzer, pH meter, and tetrazolium reduction assay. In vivo efficacies of PLGA/collagen nanofibers and PLA bolts for tendon–bone healing were investigated on a rabbit bone tunnel model with histological and tendon pullout tests. The PLGA/collagen-blended nanofibrous membrane was a hydrophilic, stable, and biocompatible scaffold. The PLA bolt was durable for tendon–bone anchoring. Histology showed adequate biocompatibility of the PLA bolt on a medial cortex with progressive bone ingrowth and without tissue overreaction. PLGA nanofibers within the bone tunnel also decreased the tunnel enlargement phenomenon and enhanced tendon–bone integration. Composite polymers of the PLA bolt and PLGA/collagen nanofibrous membrane can effectively promote outcomes of tendon reconstruction in a rabbit model. The composite biodegradable polymeric system may be useful in humans for tendon reconstruction. Keywords: polylactide–polyglycolide nanofibers, PLGA, collagen, 3D printing, polylactide, PLA, bone-anchoring bolts, tendon healing

  10. License plate detection algorithm

    Science.gov (United States)

    Broitman, Michael; Klopovsky, Yuri; Silinskis, Normunds

    2013-12-01

    A novel algorithm for vehicle license plates localization is proposed. The algorithm is based on pixel intensity transition gradient analysis. Near to 2500 natural-scene gray-level vehicle images of different backgrounds and ambient illumination was tested. The best set of algorithm's parameters produces detection rate up to 0.94. Taking into account abnormal camera location during our tests and therefore geometrical distortion and troubles from trees this result could be considered as passable. Correlation between source data, such as license Plate dimensions and texture, cameras location and others, and parameters of algorithm were also defined.

  11. Study of the projectile impact on aluminum targets divided by water

    Science.gov (United States)

    Saburi, Tei; Kubota, Shiro; Ogata, Yuji; Wada, Yuji; Nakanishi, Toshikazu

    2007-06-01

    The impact behavior of a projectile into aluminum alloy targets divided by water was experimentally observed using high-speed video camera, and a numerical simulation was conducted using LS-DYNA. The target size was 5mm in thick, 200mm in height and width. Two target plates were positioned parallel at a distance of 120-180mm, and the space between targets was filled up with water. A SNCM steel projectile was 10mm in height, and 10mm in diameter. The projectile was accelerated by a compact accelerator using an explosive, and impacted on the first target. Impact experiments without water in the gap space were also conducted. In case without water, the projectile penetrated both two targets. On the other hand, in case that water fills up in the gap, The projectile did not penetrate the second target plate, and the both target plates were entirely and largely deformed compared with the case that water is absent. Numerical simulation of the projectile impact was conducted using a finite element code of LS-DYNA. ALE(Arbitrary Lagrangian Eulerian) method was adopted to simulate fluid-structure interaction problem. The deformation behavior of targets was confirmed by the simulation, and the importance of water effect on the deformation of the targets and the de-acceleration of the projectile velocity was shown.

  12. Casimir force between metal plate and dielectric plate

    Institute of Scientific and Technical Information of China (English)

    刘中柱; 邵成刚; 罗俊

    1999-01-01

    The Casimir effect between metal plate and dielectric plate is discussed with 1+1-dimensional potential model without using cut-off method. Calculation shows that the Casimir force between metal plate and dielectric plate is determined not only by the potential V0, the dielectric thickness and the distance α between the metal plate and dielectric plate, but also by the dimension of the vessel. When α is far less than the dimension of the vessel, the Casimir force Fc∝α(-1); conversely Fc∝α-2. This result is significant for Casimir force experiment.

  13. Nuclear reactor alignment plate configuration

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-28

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

  14. The Digital Divide and Health Outcomes: A Teleretinal Imaging Study

    Science.gov (United States)

    Connolly, Kathleen Kihmm

    2013-01-01

    The purpose of this research project was to understand, explore and describe the digital divide and the relationship between technology utilization and health outcomes. Diabetes and diabetic eye disease was used as the real-life context for understanding change and exploring the digital divide. As an investigational framework, a telemedicine…

  15. Digital Natives and Digital Divide: Analysing Perspective for Emerging Pedagogy

    Science.gov (United States)

    Onye, Uriel U.; Du, Yunfei

    2016-01-01

    This paper addresses the concepts of digital natives and digital divide from the perspective of the digital outsiders (part of digital natives). It takes a critical look at the implications of available ICT in both developed and underdeveloped countries in the fight against digital divide. The major contribution to literature is by drawing…

  16. The Digital Divide in Health Education: Myth or Reality?

    Science.gov (United States)

    Stellefson, Michael; Chaney, Beth; Chaney, Don

    2008-01-01

    Although e-health interventions provide new opportunities for health education, there has been cause for concern regarding the purported information technology gap between those who have access to digital applications and those who do not--termed the "digital divide." The literature suggests, however, that this divide may now be illusory, driven…

  17. Distance Education and the Digital Divide: An Academic Perspective

    Science.gov (United States)

    Block, Judy

    2010-01-01

    This paper will address how the digital divide affects distance education. Lack of access for some students does raise concerns. Access to technology is often defined by what students don't have: what is called a digital divide. Access also is defined by the speed of Internet connections. Access in the future will be even greater as more computers…

  18. Bridging the Digital Divide--An Australian Story

    Science.gov (United States)

    Broadbent, Robyn; Papadopoulos, Theo

    2013-01-01

    There is increasing evidence that the lack of access to information and communication technology (ICT) or the "digital divide" severely limits education, employment and economic prospects. This paper reports on the evaluation of a project that aims to bridge the digital divide. In particular, the case study data has been used to bring to…

  19. Evaluation of Fatih Project in the Frame of Digital Divide

    Science.gov (United States)

    Karabacak, Kerim

    2016-01-01

    The aim of this research realized at the general survey model is to evaluate "FATIH Project" in the frame of digital divide by determining the effects of the distributed tablets to the students being educated at K-12 schools on digital divide. Sample is taking from the 9th grade students in Sakarya city in the 2013-2014 academic session.…

  20. Rethinking the Digital Divide: Impacts on Student-Tutor Relationships

    Science.gov (United States)

    Underwood, Jean D. M.

    2007-01-01

    This article emerged from a series of debates and workshops on the impact of the Digital Divide on educational practice at the "Futures of Learning: New Learning Paradigms Conference" in Paris. The conceptualisation of the Digital Divide into the "haves" and the "have-nots", with a perception of the economically…

  1. The Digital Divide and Health Outcomes: A Teleretinal Imaging Study

    Science.gov (United States)

    Connolly, Kathleen Kihmm

    2013-01-01

    The purpose of this research project was to understand, explore and describe the digital divide and the relationship between technology utilization and health outcomes. Diabetes and diabetic eye disease was used as the real-life context for understanding change and exploring the digital divide. As an investigational framework, a telemedicine…

  2. Crossing the Phantom divide line in the Chaplygin gas model

    CERN Document Server

    Sadjadi, H Mohseni

    2009-01-01

    The role of the interaction in crossing the phantom divide line in the Chaplygin gas model is discussed. We obtain some general properties of the interactions that allow the model to arrive at the phantom divide line. We show that these properties put some conditions on the ratio of dark matter to dark energy density.

  3. Create Your Plate

    Medline Plus

    Full Text Available ... 1 Type 2 About Us Online Community Meal Planning Sign In Search: Search More Sites Search ≡ Are ... Fitness Home Food MyFoodAdvisor Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten ...

  4. Create Your Plate

    Medline Plus

    Full Text Available ... Create Your Plate is a simple and effective way to manage your blood glucose levels and lose weight. With ... year of delicious meals to help prevent and manage diabetes. Healthy Recipes: ... to your day with this guide. Ways to Give: Wear Your Cause on Your Sleeve - ...

  5. The Plate Tectonics Project

    Science.gov (United States)

    Hein, Annamae J.

    2011-01-01

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

  6. Create Your Plate

    Medline Plus

    Full Text Available ... tax-deductible gift today can fund critical diabetes research and support vital diabetes education services that improve the ... way to manage your blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ...

  7. Create Your Plate

    Medline Plus

    Full Text Available ... 1 Type 2 About Us Online Community Meal Planning Sign In Search: Search More Sites Search ≡ Are ... Fitness Home Food MyFoodAdvisor Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten ...

  8. Create Your Plate

    Medline Plus

    Full Text Available ... tax-deductible gift today can fund critical diabetes research and support vital diabetes education services that improve the ... way to manage your blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ...

  9. Create Your Plate

    Medline Plus

    Full Text Available ... unsweetened tea or coffee. Featured Product Precise Portions® Go Healthy Travel Pack (4/Box) Taking the guesswork ... you are. Now, our best-selling, sectioned to-go plate with easy-sealing lid is offered in ...

  10. Create Your Plate

    Medline Plus

    Full Text Available ... manage portion control wherever you are. Now, our best-selling, sectioned to-go plate with easy-sealing lid is offered in a 4-pack. Whether ... Research & Practice We Are Research Leaders We Support Your Doctor ...

  11. INL HIP Plate Fabrication

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-02-01

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

  12. The Plate Tectonics Project

    Science.gov (United States)

    Hein, Annamae J.

    2011-01-01

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

  13. Create Your Plate

    Medline Plus

    Full Text Available ... Planning Meals > Create Your Plate Share: Print Page Text Size: A A A Listen En Español Create ... somewhere in between, you have an easy portion control solution that works. Last Reviewed: October 8, 2015 Last Edited: ... Cost of Diabetes Advocate Toolkit Call to Congress Research & ...

  14. Failure Analysis on Fracture of Worm-gear Connecting Bolts%蜗轮连接螺栓断裂失效分析

    Institute of Scientific and Technical Information of China (English)

    王荣; 李玲

    2012-01-01

    装卸料机上的蜗轮连接螺栓材料为35钢,强度等级为10.9级,在设备运行大约10a后发生断裂。对断裂螺栓进行宏观、化学成分、硬度、金相、能谱和断口分析后得出,该螺栓的断裂性质为双向弯曲疲劳断裂,螺栓表面的脱碳和螺纹颈部的应力集中降低了该部位的疲劳性能。通过综合分析和螺栓受力估算后得出,螺栓断裂的主要原因是螺栓和内齿轮螺栓孔之间存在较大的间隙,使螺栓的受力状态和受力大小过早地发生了变化,造成连接螺栓疲劳断裂。%The worm-gear connecting bolts of refueling machines of a nuclear power plant,with material of 35 steel and strength grade of 10.9,fractured after the device running for about a decade,and means such as macro examination,chemical compositions analysis,hardness test,metallographic examination,fracture SEM analysis and so on,were used to analyze the fractured bolts.The results show that the fracture property of the bolts is two-way bending fatigue fracture.Surface decarburization of the bolts and stress concentration at the bolt thread neck decreased the fatigue strength,which resulted fatigue cracks formed here.By comprehensive analysis and force estimating,it was concluded that the main reason for the fracture is that there is a big gap between the bolt shank parts and their matching internal gear bolt holes,which made the force state and force size of the bolts changed early and finally resulted in fatigue fracture of the worm-gear connecting bolts.

  15. Calculation of bolted flange connections of metal to metal contact type. Results of MPA/VGB-project SA ''AT'' 19/08

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, G. [EnBW Kernkraftwerk GmbH, Neckarwestheim (Germany); Bieselt, R. [RWE Power AG, Essen (Germany); Klucke, D. [E.ON Kernkraft GmbH, Hannover (Germany); Schuemann, D. [Vattenfall Europe, Nuclear Energy GmbH, Hamburg (Germany); Kurz, H.; Kockelmann, H. [Stuttgart Univ. (Germany). MPA

    2010-07-01

    Subject of a research project carried out at Material Testing Institute (MPA) University of Stuttgart was the investigation of bolted flange connections (DN100 PN100 and PN160) of metal-to-metal contact type. In a special test rig external loadings (axial forces, bending and torsional moments as well as shearing forces) can be applied in addition to the internal pressure. Further on an analytical approach was developed for the determination of the loading in different cross sections of the flanges and for the tightness proof by means of the gap between the flanges at the position of the gasket. On the basis of a comparison of the experimental results and those of numerical calculations with results according to the new developed analytical approach the latter can be regarded as validated as far as investigated. In the nuclear code KTA 3211.2 (draft 2003) [1] the flange rotation at metal-to-metal contact (MMC) is restricted globally to 0.1 . This limitation does not comply with a lot of bolted flange connections in service although the strength and tightness criteria are met. This problem is now resolved with the new developed analytical approach which takes also into consideration the non-negligible influence of the assembly bolt load exceeding the minimum required bolt load for metal-to-metal contact. In a following project for defined boundary conditions the basis for the strength and tightness proof for bolted flange connections (MMC type) without explicit calculation shall be created. (orig.)

  16. Design on the Transporting and Bolting Machine with Hopper and Two Arms%料斗式两臂运锚机的研制

    Institute of Scientific and Technical Information of China (English)

    马昭

    2014-01-01

    The transporting and bolting machine with hopper and two arms is a kind of equipment which is researched according to parallel working of the excavating and bolting integration on fully mechanized winning faces. It has the function of bolt supporting, materials transporting and self-driving. Its main structure, operation principle and service condition are introduced. It realizes reasonably connect of excavating, bolting and transporting work. The excavating and bolting efficiency is improved.%料斗式两臂运锚机是基于井下综掘工作面掘锚平行作业而研制的一种可进行锚杆支护和物料转运的具有自行走功能的运锚装备,本文详细介绍了该机的主要结构组成、工作原理以及使用情况,可实现掘锚运作业的合理衔接,提高了成巷效率。

  17. Quantitative evaluation of residual torque of a loose bolt based on wave energy dissipation and vibro-acoustic modulation: A comparative study

    Science.gov (United States)

    Zhang, Zhen; Liu, Menglong; Su, Zhongqing; Xiao, Yi

    2016-11-01

    A wave energy dissipation (WED)-based linear acoustic approach and a vibro-acoustic modulation (VM)-based nonlinear method were developed comparatively, for detecting bolt loosening in bolted joints and subsequently evaluating the residual torque of the loose bolt. For WED-based, an analytical model residing on the Hertzian contact theory was established, whereby WED was linked to the residual torque of a loose bolt, contributing to a linear index. For VM-based, contact acoustic nonlinearity (CAN) engendered at the joining interface, when a pumping vibration perturbs a probing wave, was interrogated, and the nonlinear contact stiffness was described in terms of a Taylor series, on which basis a nonlinear index was constructed to associate spectral features with the residual torque. Based respectively on a linear and a nonlinear premise, the two indices were validated experimentally, and the results well coincided with theoretical predication. Quantitative comparison of the two indices surmises that the VM-based nonlinear method outperforms the WED-based linear approach in terms of sensitivity and accuracy, and particularly when the bolt loosening is in its embryo stage. In addition, the detectability of the nonlinear index is not restricted by the type of the joint, against a high dependence of its linear counterpart on the joint type.

  18. 深水法兰连接机具螺栓预紧方法及装置研究%Research on Method of Bolt Tightening and Bolt Tightening Equipment of the Deep Water Flange Connection Tool

    Institute of Scientific and Technical Information of China (English)

    李伟; 王芳; 田玉江; 王上原; 王亚伟

    2012-01-01

    随着陆地和浅水油气资源的日益枯竭,急须开发深水油气资源以满足国民经济发展对能源的需求.法兰螺栓连接是深水管道连接的常用方法,也是深水管道回接必须攻克的难点.深水法兰连接机具是应用于深水管道法兰连接的一种专用设备,确定深水法兰连接机具的螺栓预紧方法对开发设计深水法兰连接机具具有重要意义,通过对比几种常用的螺栓预紧方法,确定了适用于深水的螺栓预紧方法,并设计了一种深水工作的螺栓预紧装置.该研究成果对机具的进一步开发,促进我国深水作业设备发展和提高我国深水管道连接技术具有一定意义.%Along with the wearing out of petroleum resource, petroleum resource of deep water must be exploited to improve nation economy development. The one of the methods of the deep water pipeline connection is the flange connection, but it is a difficult problem must be conquered. The deep water pipeline flange connection tool is a kind of special equipment to connect the deep water pipeline, to determine the method of the bolt tightening is important for developing the deep water pipeline flange connection tool. Through comparing the some methods of the bolt tightening, a method of the deep water bolt tightening is determined, and a set of the bolt tightening equipment is designed. The method and the equipment could promote the development of the deep sea technology and improve deep sea pipe flange connecting technology.

  19. An Application of Bolt Connect Process in Foundation Embedded Bolts and Its Repair%螺套连接工艺在预埋基础螺栓及其修复上的应用

    Institute of Scientific and Technical Information of China (English)

    周四林; 王东升

    2014-01-01

    对港口散杂货码头中锈蚀腐烂的基础预埋螺栓常规更换工艺进行了分析,揭示了其中存在的问题,通过创新更换工艺,较好地解决了上述问题。%The conventional replacement process for the seriously rusted foundation embedded bolts in bulk and general cargo terminal in the port is analyzed and so the existing problem is found out. Then the problem is solved better by innovating the replacement process.

  20. Extended end-plate connection subjected to monotonic loading: Experimental analysis and FEM simulation

    Science.gov (United States)

    Mureşan, Ioana Cristina; Bâlc, Roxana

    2017-07-01

    This paper presents an experimental investigation of a statically monotonic loaded extended end-plate connection, with preloaded high strength bolts, that was carried out at Laboratory of Faculty of Civil Engineering from Cluj-Napoca. A finite element model using the software package Abaqus [1] was developed in parallel. In order to calibrate the numerical model, the results were analyzed on the basis of moment-rotation curves, stress distribution state and the failure mode of connection. Then, a study was conducted on the numerical model by using a high strength steel (HSS) and changing the stiffness and strength characteristics of some elements. Validation of the numerical modeling was performed against the experimental results and it can be seen that good agreements exist in general.

  1. MyPlate Food Guide

    Science.gov (United States)

    ... Choosing the Right Sport for You Shyness MyPlate Food Guide KidsHealth > For Teens > MyPlate Food Guide Print ... other sugary drinks. Avoid oversized portions. continue Five Food Groups Different food groups meet different nutrition needs. ...

  2. What Are Growth Plate Injuries?

    Science.gov (United States)

    ... plate injuries are:  Falling down  Competitive sports (like football)  Recreational activities. Other reasons for growth plate injuries are:  Child abuse  Injury from extreme cold (for ...

  3. Controlling Laminate Plate Elastic Behavior

    OpenAIRE

    Mareš, T.

    2004-01-01

    This paper aims to express the relation of a measure of laminate plate stiffness with respect to the fiber orientation of its plies. The inverse of the scalar product of the lateral displacement of the central plane and lateral loading of the plate is the measure of laminate plate stiffness. In the case of a simply supported rectangular laminate plate this measure of stiffness is maximized, and the optimum orientation of its plies is searched.

  4. Microchannel plate streak camera

    Science.gov (United States)

    Wang, Ching L.

    1989-01-01

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

  5. Ultrasonic testing of core baffle former bolts of the core tanks of pressurised water reactors; Ultraschallpruefung von Kernumfassungsschrauben der Kernbehaelter von Druckwasserreaktoren

    Energy Technology Data Exchange (ETDEWEB)

    Bies, Christian M.; Alaerts, Louis; Bonitz, Frank W. [Westinghouse Electric Germany GmbH, Mannheim (Germany); Devlin, Russell S.; Minogue, Patrick [WesDyne International, Madison, PA (United States)

    2013-07-01

    This article presents the MIDAS VI testing robot used by Westinghouse / WesDyne. This is a remotely operated underwater vehicle which positions ultrasonic probes under camera control. This vehicle makes it possible to substantially reduce the time required for setting up and preparing ultrasonic tests on core baffle former bolts. It has also accelerated the test procedure itself. Test methods have also been developed for bolt types which were hitherto considered incapable of being tested. One of these methods is based on a phased array probe. The article also reports on experiences gained over the course of years in testing core baffle former bolts in European nuclear power plants using the SUPREEM testing robot.

  6. A Line Dividing "Trademark License" and "Trademark Infringement"

    Institute of Scientific and Technical Information of China (English)

    Chi Shaojie

    2004-01-01

    @@ Opinions are not divided on in fringement by another person's use of a registered trademark without license from the trademark registrant,nor on the non-infringement by its/his licensed use of a registered trademark.

  7. Pulse swallowing frequency divider with low power and compact structure

    Institute of Scientific and Technical Information of China (English)

    Gao Haijun; Sun Lingling; Cai Chaobo; Zhan Haiting

    2012-01-01

    A pulse swallowing frequency divider with low power and compact structure is presented.One of the DFFs in the divided by 2/3 prescaler is controlled by the modulus control signal,and automatically powered off when it has no contribution to the operation of the prescaler.The DFFs in the program counter and the swallow counter are shared to compose a compact structure,which reduces the power consumption further.The proposed multi-modulus frequency divider was implemented in a standard 65 nm CMOS process with an area of 28 ×22 μm2.The power consumption of the divider is 0.6 mW under 1.2 V supply voltage when operating at 988 MHz.

  8. Continental Divide of the United States - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map layer portrays the Continental Divide of the United States. The map layer was created by extracting Hydrologic Unit Boundary line features from an existing...

  9. Annan warns of 'content divide' between rich and poor

    CERN Multimedia

    Dickson, D

    2003-01-01

    "The Secretary-General of the United Nations, Kofi Annan, warned today (10 December) that a "content divide" is threatening to deprive developing countries of the full benefits offered by information and communications technologies (ICTs)" (1 page)

  10. Electronic Equipment Cold Plates

    Science.gov (United States)

    1976-04-01

    equations for such a flow regiae. For laainar flow and Moderate teaperature differwwe« between the well «nd coolant, a aodifled Sieder -Tate...con- figuration. The heat-transfer coefficients, therefore, were determined by using both the Sieder -Tate and McAdams equations and the coaputed...values used In the analytical predictions. As with th* previous cold Plates, the Sieder -Tate equation gave too low of values for the heat- transfer

  11. Elastic plate spallation

    Science.gov (United States)

    Oline, L.; Medaglia, J.

    1972-01-01

    The dynamic finite element method was used to investigate elastic stress waves in a plate. Strain displacement and stress strain relations are discussed along with the stiffness and mass matrix. The results of studying point load, and distributed load over small, intermediate, and large radii are reported. The derivation of finite element matrices, and the derivation of lumped and consistent matrices for one dimensional problems with Laplace transfer solutions are included. The computer program JMMSPALL is also included.

  12. Plate Tearing by a Cone

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1997-01-01

    The present paper is concerned with steady-state plate tearing by a cone. This is a scenario where a cone is forced through a ductile metal plate with a constant lateral tip penetration in a motion in the plane of the plate. The considered process could be an idealisaton of the damage, which...

  13. Plate Tearing by a Cone

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1998-01-01

    The present paper is concerned with steady-state plate tearing by a cone. This is a scenario where a cone is forced through a ductile metal plate with a constant lateral tip penetration in a motion in the plane of the plate. The considered process could be an idealisation of the damage, which...

  14. An improved fractional divider for fractional-N frequency synthesizers

    Science.gov (United States)

    Zhang, Wei; Liu, Yang; Zhou, Yongqi

    2009-07-01

    This paper presents an improved fractional divider used in 1.8~2GHz fractional-N frequency synthesizers. A new clock setting for delta-sigma modulator (DSM) is proposed to prevent the potential problems of traditional fractional dividers: the DSM output would be wrongly loaded and the action of DSM circuit may affect the phase-detection of phase-frequency-detector (PFD). Simulation result shows the effectiveness of this improvement.

  15. Agile Development & Software Architecture - Crossing the Great Divide

    Science.gov (United States)

    2016-06-07

    2010 Carnegie Mellon University SEI Webinar Series: Agile Development & Software Architecture – Crossing the Great Divide Software Engineering...2010 4. TITLE AND SUBTITLE Agile Development & Software Architecture - Crossing the Great Divide 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...Mellon University , Software Engineering Institute,Pittsburgh,PA,15213 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S

  16. Effect of CO2 enrichment on the glucosinolate contents under different nitrogen levels in bolting stem of Chinese kale (Brassica alboglabra L.)

    Institute of Scientific and Technical Information of China (English)

    Gui-xiao LA; Ping FANG; Yi-bo TENG; Ya-juan LI; Xian-yong LIN

    2009-01-01

    The effects of CO2 enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassioa alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height,stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO2 concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem,11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO2 concentration, N concentration, and CO2×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO2. However, at 20 mmol N/L,elevated CO2 had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO2 concentration in the three N treatments, resulting in changes in the C/N and N/S ratios.Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO2 concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO2 condition.

  17. Effect of CO2 enrichment on the glucosinolate contents under different nitrogen levels in bolting stem of Chinese kale (Brassica alboglabra L.).

    Science.gov (United States)

    La, Gui-xiao; Fang, Ping; Teng, Yi-bo; Li, Ya-juan; Lin, Xian-yong

    2009-06-01

    The effects of CO(2) enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassica alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO(2) concentration was elevated from 350 to 800 microl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO(2) concentration, N concentration, and CO(2)xN interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO(2). However, at 20 mmol N/L, elevated CO(2) had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO(2) concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO(2) concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO(2) condition.

  18. Higher performance in rockbolting technology by use of immediate-bearing grouted bolts; Leistungssteigerung in der Ankertechnik durch Einsatz sofort tragender Injektionsanker

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Archibald; Eigemann, Ernst A. [Minova CarboTech GmbH, Essen (Germany)

    2009-01-29

    Efficient support technology and in particular rockbolting systems are increasingly important under ever more difficult working conditions. Recognised worldwide as an efficient, innovative and highly automated mining company RAG relies on high-quality, economical support concepts for one of the most demanding coal deposits in the world. Two new methods for setting immediate-bearing bolts with the use of a highly reactive bolt resin and prospects of replacement of wire mesh by a shotsscreting system in roadway supports are described in this contribution. (orig.)

  19. Conventional drivage of gate roads with bolted supports. Indication of performance potential; Konventionelle Auffahrung von Floezstrecken mit Ankerausbau. Aufzeigen von Leistungspotenzialen

    Energy Technology Data Exchange (ETDEWEB)

    Beimdieck, J. [RAG Anthrazit Ibbenbueren GmbH, Ibbenbueren (Germany). Bereich Bergbau; Stoettner, M.T. [RAG Anthrazit Ibbenbueren GmbH, Ibbenbueren (Germany). Bereich Stab

    2008-06-19

    The road drivages at the Ibbenbueren mine are highly standardised. Drivage is carried out exclusively by drilling and shortfiring. A three-layer combined support - bolting, arches and backfilling with concrete - is used. Alternatives were sought in order to achieve a further increase in performance and reduce costs. Meanwhile the mine is driving 2 roadways by blasting and with only bolted supports. The equipment and process optimisations of the old standard were utilised with considerable increases in performance. The article describes the initial experience required. (orig.)

  20. Plate tectonics conserves angular momentum

    Directory of Open Access Journals (Sweden)

    C. Bowin

    2009-03-01

    Full Text Available A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4 E+27 kgm2s−1. Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates. Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth. The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant velocity on the crests of convection cells driven by rising heat. These results imply that spreading centers are primarily passive reactive

  1. Vehicle License Plate Recognition Syst

    Directory of Open Access Journals (Sweden)

    Meenakshi,R. B. Dubey

    2012-12-01

    Full Text Available The vehicle license plate recognition system has greater efficiency for vehicle monitoring in automatic zone access control. This Plate recognition system will avoid special tags, since all vehicles possess a unique registration number plate. A number of techniques have been used for car plate characters recognition. This system uses neural network character recognition and pattern matching of characters as two character recognition techniques. In this approach multilayer feed-forward back-propagation algorithm is used. The performance of the proposed algorithm has been tested on several car plates and provides very satisfactory results.

  2. Neural Correlates of Divided Attention in Natural Scenes.

    Science.gov (United States)

    Fagioli, Sabrina; Macaluso, Emiliano

    2016-09-01

    Individuals are able to split attention between separate locations, but divided spatial attention incurs the additional requirement of monitoring multiple streams of information. Here, we investigated divided attention using photos of natural scenes, where the rapid categorization of familiar objects and prior knowledge about the likely positions of objects in the real world might affect the interplay between these spatial and nonspatial factors. Sixteen participants underwent fMRI during an object detection task. They were presented with scenes containing either a person or a car, located on the left or right side of the photo. Participants monitored either one or both object categories, in one or both visual hemifields. First, we investigated the interplay between spatial and nonspatial attention by comparing conditions of divided attention between categories and/or locations. We then assessed the contribution of top-down processes versus stimulus-driven signals by separately testing the effects of divided attention in target and nontarget trials. The results revealed activation of a bilateral frontoparietal network when dividing attention between the two object categories versus attending to a single category but no main effect of dividing attention between spatial locations. Within this network, the left dorsal premotor cortex and the left intraparietal sulcus were found to combine task- and stimulus-related signals. These regions showed maximal activation when participants monitored two categories at spatially separate locations and the scene included a nontarget object. We conclude that the dorsal frontoparietal cortex integrates top-down and bottom-up signals in the presence of distractors during divided attention in real-world scenes.

  3. Generation of five phase-locked harmonics by implementing a divide-by-three optical frequency divider

    CERN Document Server

    Suhaimi, Nurul Sheeda; Gavara, Trivikramarao; Nakagawa, Ken'ichi; Hong, Feng Lei; Katsuragawa, Masayuki

    2015-01-01

    We report the generation of five phase-locked harmonics, f_1: 2403 nm, f_2: 1201 nm, f_3: 801 nm, f_4: 600 nm, and f_5: 480 nm with an exact frequency ratio of 1 : 2 : 3 : 4 : 5 by implementing a divide-by-three optical-frequency divider in the high harmonic generation process. All five harmonics are generated coaxially with high phase coherence in time and space, which are applicable for various practical uses.

  4. Damage Detection of Closed Crack in a Metallic Plate Using Nonlinear Ultrasonic Time Reversal Method

    Directory of Open Access Journals (Sweden)

    Wang Zhang

    2013-01-01

    Full Text Available Initial cracks in metallic structures incline to be closed at rest. Such incipient damage generally fails to be detected and located with traditional linear ultrasonic techniques because ultrasonic waves penetrate the contact area of the closed crack. In this paper, an imaging algorithm based on nonlinear ultrasonic time reversal method is proposed to detect closed cracks in aluminum plates. Two surface-bonded piezoelectric transducer arrays are used to generate, receive, and reemit ultrasonic wave signals. The closed crack is simulated by tightening a bolt on the aluminum plate. By applying large amplitude excitation voltage on the PZT transducers, the closed crack could be opened and closed. The transmitted waves recorded by PZT array contain nonlinear components, the signals are time reversed and emitted back, and the tone burst reconstructions are achieved. The linear reciprocity and the time reversibility break down due to the presence of the nonlinear components. The correlation coefficient between the original excitation signal and the reconstructed signal is calculated to define the damage index for individual sensing path and is used to develop an imaging algorithm to locate the closed crack on the plate. The experimental results demonstrate that incident wave signals and their reconstructed signals can be used to accurately detect and locate closed cracks.

  5. A diffuse plate boundary model for Indian Ocean tectonics

    Science.gov (United States)

    Wiens, D. A.; Demets, C.; Gordon, R. G.; Stein, S.; Argus, D.

    1985-01-01

    It is suggested that motion along the virtually aseismic Owen fracture zone is negligible, so that Arabia and India are contained within a single Indo-Arabian plate divided from the Australian plate by a diffuse boundary. The boundary is a zone of concentrated seismicity and deformation commonly characterized as 'intraplate'. The rotation vector of Australia relative to Indo-Arabia is consistent with the seismologically observed 2 cm/yr of left-lateral strike-slip along the Ninetyeast Ridge, north-south compression in the Central Indian Ocean, and the north-south extension near Chagos.

  6. Cold plate with combined inclined impingement and ribbed channels

    Energy Technology Data Exchange (ETDEWEB)

    Parida, Pritish R.

    2015-12-22

    Heat transfer devices and methods for making the same that include a first enclosure having at least one inlet port; a second enclosure having a bottom plate and one or more dividing walls to establish channels, at least one internal surface of each channel having rib structures to create turbulence in a fluid flow; and a jet plate connecting the first enclosure and the second enclosure having impinging jets that convey fluid from the first enclosure to the channels, said impinging jets being set at an angular deviation from normal to cause local acceleration of fluid and to increase a local heat transfer rate.

  7. Cortisol Hormone Concentration and Meat Quality of Beef Cattle Stunned by Captive Bolt Stun Gun before Slaughtering

    Directory of Open Access Journals (Sweden)

    K. Maghfiroh

    2014-12-01

    Full Text Available This study was aimed to describe cortisol hormone concentration and meat quality which were produced in beef cattle stunned with captive bolt stun gun before slaughtering. Blood and meat samples were taken from Brahman cross steers (n= 11 in two abattoirs located in West Java and Banten. Blood samples were collected immediately after slaughtering. Cortisol hormone concentration in the serum was measured by using radioimmunoassay (RIA. The descriptive, correlation, and regression analyses were used to interprete data. Meat quality assessment was based on pH, cooking loss, and complete drainage of blood. The average of cortisol hormone concentration was 26.59 ng/mL. Meat pH at 1 h postmortem and 24 h postmortem were 6.65 and 6.21, respectively. Meat cooking loss was 26.77%. Blood drainage in meat samples of each cattle showed complete drainage. There was a significant correlation (P<0.05 between cortisol concentrations and pH at 1 hour postmortem as well as cortisol concentration and cooking loss. There was no significant correlation between pH at 24 h postmortem and cooking loss. Cattle was stunned with a captive bolt stun gun before slaughtering produced meat with complete blood drainage but had high cortisol hormone concentration and pH ultimate.

  8. 基于ADAMS的枪机碰撞力研究%Bolt's Impact Simulation Based on ADAMS

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    In this paper ,the simple model of the barrel and automation was established by ADAMS ,the counter-recoil velocity and the mass of bolt and bolt box were defined by Impact function in ADAMS ,and the accurate control of step size and interpolation algorithm was realized ,then the counter-recoil collision force was obtained .%  建立由枪管和自动机构件组成的简易模型,通过在ADAMS中进行动力学仿真,赋予枪机和枪机框实际的复进到位速度和质量,利用ADAMS中的Impact函数对参数进行设置,并对求解步长和插值算法等进行精确控制,对结果进行测量,得到了枪机复进到位的碰撞力。

  9. AVSA. Parallelised bolting and cutting in roadways with arch supports; AVSA. Parallelisiertes Ankern und Schneiden in Bogenstrecken

    Energy Technology Data Exchange (ETDEWEB)

    Matusche, T. [Bergwerk West, Kamp-Lintfort (Germany); Stratmann, T. [Deutsche Steinkohle AG (DSK), Herne (Germany). Abt. TB

    2002-09-05

    In the middle of the 90's a research project was initiated to improve the drivage rates of roadway headings in the German hard coal industry. The target of the project was to get a significant increase in performance by parallelisation of cutting and bolting in mechanical headings, also in very hard rock conditions. In the first operation the prototype of the developed heading machine achieved not the expected performance. Although the aim of parallel cutting and bolting was gained, the drivage performance was especially hampered due to a high amount of hunks during the cutting process. Additionally geological difficulties occurred. Steps were made to optimize this system getting a clear increase in performance for the second operation to achieve the initial target. (orig.) [German] Vor dem Hintergrund stagnierender Vortriebsgeschwindigkeiten im Floezstreckenvortrieb des deutschen Steinkohlenbergbaus wurde Mitte der 90er Jahre des letzten Jahrhunderts ein Forschungsvorhaben initiiert. Ziel war es, durch Parallelisierung von Schneid- und Ankerarbeit bei maschinellen Vortrieben eine signifikante Leistungserhoehung auch in schwer schneidbarem Gestein zu erzielen. Der entwickelte Prototyp erreichte in einem ersten Einsatz die erwartete Leistung nicht. Obwohl die angestrebte Parallelisierung der Vorgaenge Schneiden und Ankern erreicht wurde, behinderte insbesondere ein hoher Brockenanfall die Vortriebsleistung. Zusaetzlich traten geologische Probleme auf. Optimierungsmassnahmen sollen in einem zweiten Einsatz deutliche Leistungssteigerungen bewirken, um die urspruengliche Zielsetzung zu erreichen. (orig.)

  10. Face end position with cable bolt technology at the Walsum colliery; Strebendstellung in Seilankertechnik auf dem Bergwerk Walsum

    Energy Technology Data Exchange (ETDEWEB)

    Maucher, B.; Paulussen, W.; Rosinski, D. [Ruhrkohle Niederrhein AG, Duisburg (Germany). Bergwerk Walsum; Mogk, E.; Kulassek, M. [Bergamt Moers (Germany)

    1998-09-17

    In 1997 for the first time in German hard coal mining cable bolts at salvage faces were used at the Walsum mine. For this technical innovation a Flex-Drill-machine of Hebben und Fischbach was used during a research and development program. The commercially available cable bolts were modified at the Walsum mine for imbedding in polyurethane grout. The initial use was in the salvage face P 92 with a face opening of 3.3 m. The length of the shields was up to 7 m. The development and realisation of the support concept took place in close cooperation with the Bergamt Moers. (orig.) [Deutsch] Auf dem Bergwerk Walsum wurde im Jahr 1997 erstmalig im deutschen Steinkohlenbergbau eine Strebendstellung in Vollankerung hergestellt und mit Seilanker ausgebaut. Fuer diese technische Neuheit kam im Rahmen eines Forschungs- und Entwicklungsvorhabens das Flex-Drill-Bohrgeraet der Firma Hebben und Fischbach zum Einsatz. Die verwendeten handelsueblichen Seilanker wurden auf dem Bergwerk Walsum fuer die Verklebung mit Polyurethan modifiziert. Der Ersteinsatz wurde in der Strebendstellung der Bauhoehe P-92 bei einer Streboeffnung von rund 3,30 m durchgefuehrt. Die Laenge des zu raubenden Schildausbaus betrug nahezu 7 m. Die Entwicklung und Realisierung des Ausbaukonzepts erfolgte in enger und konstruktiver Zusammenarbeit mit dem Bergamt Moers. (orig.)

  11. Structural health monitoring for bolt loosening via a non-invasive vibro-haptics human-machine cooperative interface

    Science.gov (United States)

    Pekedis, Mahmut; Mascerañas, David; Turan, Gursoy; Ercan, Emre; Farrar, Charles R.; Yildiz, Hasan

    2015-08-01

    For the last two decades, developments in damage detection algorithms have greatly increased the potential for autonomous decisions about structural health. However, we are still struggling to build autonomous tools that can match the ability of a human to detect and localize the quantity of damage in structures. Therefore, there is a growing interest in merging the computational and cognitive concepts to improve the solution of structural health monitoring (SHM). The main object of this research is to apply the human-machine cooperative approach on a tower structure to detect damage. The cooperation approach includes haptic tools to create an appropriate collaboration between SHM sensor networks, statistical compression techniques and humans. Damage simulation in the structure is conducted by releasing some of the bolt loads. Accelerometers are bonded to various locations of the tower members to acquire the dynamic response of the structure. The obtained accelerometer results are encoded in three different ways to represent them as a haptic stimulus for the human subjects. Then, the participants are subjected to each of these stimuli to detect the bolt loosened damage in the tower. Results obtained from the human-machine cooperation demonstrate that the human subjects were able to recognize the damage with an accuracy of 88 ± 20.21% and response time of 5.87 ± 2.33 s. As a result, it is concluded that the currently developed human-machine cooperation SHM may provide a useful framework to interact with abstract entities such as data from a sensor network.

  12. Pressure losses at dividing and combining junctions in a molten carbonate fuel cell stack

    Science.gov (United States)

    Hirata, Haruhiko; Nakagaki, Takao; Hori, Michio

    The pressure losses at manifold junctions in a molten carbonate fuel cell (MCFC) stack depend on the stacking positions of the cells and the flow rate in the manifold. These pressure losses affect the uniformity of gas flow rate in each stacked cell and consequently also affect the cell performance. In this study, the pressure losses at dividing and combining junctions in a plate heat-exchanger type MCFC stack were examined by numerical analysis. A stack consisting of 100 cells was assumed, and the junction pressure losses at various stacking positions of cells were calculated under various flow rate conditions ranging from the minimum possible flow rate (80% utilization of fuel gas) to the maximum possible flow rate (10% utilization of oxidant gas). The results were arranged according to the equations for loss coefficients, and were compared with the experimental results of previous studies.

  13. Temperature field of steel plate cooling process after plate rolling

    Directory of Open Access Journals (Sweden)

    Huijun Feng, Lingen Chen, Fengrui Sun

    2015-01-01

    Full Text Available Based on numerical calculation with Matlab, the study on cooling process after plate rolling is carried out, and the temperature field distribution of the plate varying with the time is obtained. The effects of the plate thickness, final rolling temperature, cooling water temperature, average flow rate of the cooling water, carbon content of the plate and cooling method on the plate surface and central temperatures as well as final cooling temperature are discussed. For the same cooling time, the plate surface and central temperatures as well as their temperature difference increase; with the decrease in rolling temperature and the increase in average flow rate of the cooling water, the plate surface and central temperatures decrease. Compared with the single water cooling process, the temperature difference between the plate centre and surface based on intermittent cooling is lower. In this case, the temperature uniformity of the plate is better, and the corresponding thermal stress is lower. The fitting equation of the final cooling temperature with respect to plate thickness, final rolling temperature, cooling water temperature and average flow rate of the cooling water is obtained.

  14. Real Plates and Dubious Microplates

    Science.gov (United States)

    Kogan, M. G.; Steblov, G. M.

    2008-12-01

    From the onset of plate tectonics, the existence of most of the plates was never put in doubt, although the boundaries of some plates, like Africa, were later revised. There are however, two microplates in northeast Asia, the Amurian and Okhotsk, whose existence and the sense of rotation was revised several times. The rms value of plate-residual GPS velocities is 0.5-0.9 mm/a for sets of stations representing the motion of the following plates: Antarctic, Australian, Eurasian, North American, Nubian, Pacific, and South American. This value can be regarded as an upper bound on deviation of real plates from infinite stiffness. The rms value of plate-residual GPS velocities is 1.2-1.8 mm/a for the Indian, Nazca, and Somalian plates. Higher rms values for India and Nazca are attributed to the noisier data. The higher rms value for Somalia appears to arise from the distributed deformation to the east of the East African Rift; whether this statement is true can only be decided from observations of denser network in the future. From the analysis of plate-residual GPS velocities, the Canadian Arctic and northeastern Siberia belong to the North American plate. The detailed GPS survey on Sakhalin Island shows that the Sea of Okhotsk region also belongs to the North American plate while the region to the west of it belongs to the Eurasian plate. These results provide a constraint on the geometry of the North American plate and put in doubt the existence of smaller plates in northeast Asia.

  15. [Promoting nursing competitiveness: introduction to the digital divide].

    Science.gov (United States)

    Lin, Chun-Hsu; Lee, Ting-Ting

    2010-02-01

    Increasingly sophisticated information technology (IT) has widened the gap (the so-called "digital divide") between those with effective access to IT resources and those without. Problems related to the digital divide exist in every country. In addition to level of familiarity with technology, the divide can also be influenced by factors of race, gender, age, education, economic status and area of residence. The digital divide may be ameliorated through technology innovations in terms of access to information, information application and information literacy. As IT is an increasingly significant component of modern healthcare, it may be expected that the "width" of the potential gap widens as IT applications increase in sophistication. Nursing professionals must keep abreast of advancing technologies in order to narrow the digital divide. To cope with this challenge, nursing professionals should enhance their understanding of new technologies beyond what is taught in formal education curricula. This knowledge enhancement may be attained through self learning or on-the-job training in nursing informatics. Content could cover hospital information system (IS) usage, security, applications and web access. This will improve the ability of nursing staff to face the current IT challenge.

  16. Romania's Digital Divide and the Failures of E-Government

    Directory of Open Access Journals (Sweden)

    Sorin Dan ŞANDOR

    2006-02-01

    Full Text Available This paper tries to measure the level of the digital divide existing in Romania and also to verify its relationship with e-government. At the country level, Romania is one of the least digitally developed countries in Europe, but it has shown a sharp increase in recent years. At the social level, based on data from public opinion surveys, digital divide is analyzed at two levels: lack of access and lack of knowledge. The results are similar to those in other countries: digital divide appears along the same dimensions: rural/urban, age, education, wealth and, to a lesser extent, gender. E-government services, while presumed to be at an adequate level, are used only by a very small number of citizens, thus having no impact upon the digital divide. Confronted with a serious divide, and with great possibility of its increasing, Romania needs to promote policies designed to increase access and knowledge. Also, e-government is not possible, unless administrative culture and procedures change.

  17. Plate Full of Color

    Centers for Disease Control (CDC) Podcasts

    2008-08-04

    The Eagle Books are a series of four books that are brought to life by wise animal characters - Mr. Eagle, Miss Rabbit, and Coyote - who engage Rain That Dances and his young friends in the joy of physical activity, eating healthy foods, and learning from their elders about health and diabetes prevention. Plate Full of Color teaches the value of eating a variety of colorful and healthy foods.  Created: 8/4/2008 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 8/5/2008.

  18. Dynamics of Tectonic Plates

    CERN Document Server

    Pechersky, E; Sadowski, G; Yambartsev, A

    2014-01-01

    We suggest a model that describes a mutual dynamic of tectonic plates. The dynamic is a sort of stick-slip one which is modeled by a Markov random process. The process defines a microlevel of the dynamic. A macrolevel is obtained by a scaling limit which leads to a system of integro-differential equations which determines a kind of mean field systems. Conditions when Gutenberg-Richter empirical law are presented on the mean field level. These conditions are rather universal and do not depend on features of resistant forces.

  19. Dynamics of Tectonic Plates

    OpenAIRE

    2014-01-01

    We suggest a model that describes a mutual dynamic of tectonic plates. The dynamic is a sort of stick-slip one which is modeled by a Markov random process. The process defines a microlevel of the dynamic. A macrolevel is obtained by a scaling limit which leads to a system of integro-differential equations which determines a kind of mean field systems. Conditions when Gutenberg-Richter empirical law are presented on the mean field level. These conditions are rather universal and do not depend ...

  20. Transition State Theory for dissipative systems without a dividing surface

    CERN Document Server

    Revuelta, F; Benito, R M; Borondo, F

    2015-01-01

    Transition State Theory is a central cornerstone in reaction dynamics. Its key step is the identification of a dividing surface that is crossed only once by all reactive trajectories. This assumption is often badly violated, especially when the reactive system is coupled to an environment. The calculations made in this way then overestimate the reaction rate and the results depend critically on the choice of the dividing surface. In this Letter, we study the phase space of a stochastically driven system close to an energetic barrier in order to identify the geometric structure unambiguously determining the reactive trajectories, which is then incorporated in a simple rate formula for reactions in condensed phase that is both independent of the dividing surface and exact.

  1. Bridging the Digital Divide for urban seniors: community partnership.

    Science.gov (United States)

    Cresci, M Kay; Jarosz, Patricia A

    2010-01-01

    Computers and the Internet offer older adults resources for improving health. For many older adults, the "Digital Divide" (the social, economic, and demographic factors that exist between individuals who use computers and those who do not) is a barrier to taking advantage of these resources. Bridging the Digital Divide by making computers and the Internet more accessible and making online health information more usable for older adults has the potential to improve health of older adults. This article describes a strategy for closing the Digital Divide for urban seniors through the formation of a community- university partnership with the goal of improving health and well-being through the use of online health information.

  2. Ouroboros: A Tool for Building Generic, Hybrid, Divide& Conquer Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J R; Foster, I

    2003-05-01

    A hybrid divide and conquer algorithm is one that switches from a divide and conquer to an iterative strategy at a specified problem size. Such algorithms can provide significant performance improvements relative to alternatives that use a single strategy. However, the identification of the optimal problem size at which to switch for a particular algorithm and platform can be challenging. We describe an automated approach to this problem that first conducts experiments to explore the performance space on a particular platform and then uses the resulting performance data to construct an optimal hybrid algorithm on that platform. We implement this technique in a tool, ''Ouroboros'', that automatically constructs a high-performance hybrid algorithm from a set of registered algorithms. We present results obtained with this tool for several classical divide and conquer algorithms, including matrix multiply and sorting, and report speedups of up to six times achieved over non-hybrid algorithms.

  3. Selectively Distracted: Divided Attention and Memory for Important Information.

    Science.gov (United States)

    Middlebrooks, Catherine D; Kerr, Tyson; Castel, Alan D

    2017-08-01

    Distractions and multitasking are generally detrimental to learning and memory. Nevertheless, people often study while listening to music, sitting in noisy coffee shops, or intermittently checking their e-mail. The current experiments examined how distractions and divided attention influence one's ability to selectively remember valuable information. Participants studied lists of words that ranged in value from 1 to 10 points while completing a digit-detection task, while listening to music, or without distractions. Though participants recalled fewer words following digit detection than in the other conditions, there were no significant differences between conditions in terms of selectively remembering the most valuable words. Similar results were obtained across a variety of divided-attention tasks that stressed attention and working memory to different degrees, which suggests that people may compensate for divided-attention costs by selectively attending to the most valuable items and that factors that worsen memory do not necessarily impair the ability to selectively remember important information.

  4. Enhanced Model of Nonlinear Spiral High Voltage Divider

    Directory of Open Access Journals (Sweden)

    V. Panko

    2015-04-01

    Full Text Available This paper deals with the enhanced accurate DC and RF model of nonlinear spiral polysilicon voltage divider. The high resistance polysilicon divider is a sensing part of the high voltage start-up MOSFET transistor that can operate up to 700 V. This paper presents the structure of a proposed model, implemented voltage, frequency and temperature dependency, and scalability. A special attention is paid to the ability of the created model to cover the mismatch and influence of a variation of process parameters on the device characteristics. Finally, the comparison of measured data vs. simulation is presented in order to confirm the model validity and a typical application is demonstrated.

  5. Engineering the Divide-and-Conquer Closest Pair Algorithm

    Institute of Scientific and Technical Information of China (English)

    Ming-hui Jiang; Joel gillespie

    2007-01-01

    We improve the famous divide-and-conquer algorithm by Bentley and Shamos for the planar closest-pair problem. For n points on the plane, our algorithm keeps the optimal O(n log n) time complexity and, using a circle-packing property, computes at most 7n/2 Euclidean distances, which improves Ge et al.'s bound of (3n log n)/2 Euclidean distances. We present experimental results of our comparative studies on four different versions of the divide-and-conquer closest pair algorithm and propose two effective heuristics.

  6. Transformer-based design techniques for oscillators and frequency dividers

    CERN Document Server

    Luong, Howard Cam

    2016-01-01

    This book provides in-depth coverage of transformer-based design techniques that enable CMOS oscillators and frequency dividers to achieve state-of-the-art performance.  Design, optimization, and measured performance of oscillators and frequency dividers for different applications are discussed in detail, focusing on not only ultra-low supply voltage but also ultra-wide frequency tuning range and locking range.  This book will be an invaluable reference for anyone working or interested in CMOS radio-frequency or mm-Wave integrated circuits and systems.

  7. Google and the digital divide the bias of online knowledge

    CERN Document Server

    Segev, Elad

    2010-01-01

    Beneficial to scholars and students in the fields of media and communication, politics and technology, this book outlines the significant role of search engines in general and Google in particular in widening the digital divide between individuals, organisations and states. It uses innovative methods and research approaches to assess and illustrate the digital divide by comparing the popular search queries in Google and Yahoo in different countries as well as analysing the various biases in Google News and Google Earth. The different studies developed and presented in this book provide various

  8. CMS Resistive plate Champers

    CERN Document Server

    Zainab, Karam

    2013-01-01

    There are many types of gas detectors which are used in CERN in LHC project, There is a main parts for the gas detectors which must be in all gas detectors types like Multiwire proportional chambers, such as the micromesh gaseous structure chamber (the MicroMegas), Gas-electron multiplier (GEM) detector, Resistive Plate Champers... Compact Muon Solenoid (CMS) experiment detecting muons which are powerful tool for recognizing signatures of interesting physics processes. The CMS detector uses: drift tube (DT), cathode strip chamber (CSC) and resistive plate chamber (RPC). Building RPC’s was my project in summer student program (hardware). RPC’s have advantages which are triggering detector and Excellent time resolution which reinforce the measurement of the correct beam crossing time. RPC’s Organized in stations :  RPC barrel (RB) there are 4 stations, namely RB1, RB2, RB3, and RB4  While in the RPC endcap (RE) the 3 stations are RE1, RE2, and RE3. In the endcaps a new starion will be added and this...

  9. Vibration Analysis of Plates by MLS-Element Method

    Science.gov (United States)

    Zhou, L.; Xiang, Y.

    2010-05-01

    This paper presents a novel numerical method, the moving least square element (MLS-element) method for the free vibration analysis of plates based on the Mindlin shear deformable plate theory. In the MLS-element method, a plate can be first divided into multiple elements which are connected through selected nodal points on the interfaces of the elements. An element can be of any shape and the size of the element varies dependent on the problem at hand. The shape functions of the element for the transverse displacement and the rotations are derived based on the MLS interpolation technique. The convergence and accuracy of the method can be controlled by either increasing the number of elements or by increasing the number of MLS interpolation points within elements. Two selected examples for vibration of a simply supported square Mindlin plate and a clamped L-shaped Mindlin plate are studied to illustrate the versatility and accuracy of the proposed method. It shows that the proposed method is highly accurate and flexible for the vibration analysis of plate problems. The method can be further developed to bridge the existing meshless method and the powerful finite element method in dealing with various engineering computational problems, such as large deformation and crack propagation in solid mechanics.

  10. Complications during removal of conventional versus locked compression plates: is there a difference?

    Science.gov (United States)

    Neumann, Hanjo; Stadler, Anne; Heuer, Hinrich; Auerswald, Marc; Gille, Justus; Schulz, Arndt Peter; Kienast, Benjamin

    2017-08-01

    Osteosynthesis plate removal is one of the most commonly performed procedures in orthopaedic surgery. Due to technological advances and the quality of increasing osteosynthesis material, more and more locked plates have been implanted over the last 20 years. The aim of this study was to determine whether the complication rate during plate removal differs between conventional and locked plates. In this retrospective cohort study, 620 patients were included and divided into two groups based on the type of plate (locked and conventional). Technical complications during implant removal included screw breakage, destroyed screw head, implant breakage, remaining implant material, refracture, bony or soft tissue overgrowth. The following plate-associated complications were identified: osteosynthesis plate not detachable, plate bent or broken, necessity of special tools or plate loosened. Three types of screw-related complications were observed: screw not detachable, screw broken or screw dislocated. Overall, complications related to the plate or screws were documented in 110 of the 620 cases. These complications occurred in 48 of the 382 cases involving conventional osteosynthesis (7.7% of all removals, 12.6% of all conventional removals) and in 62 of the 238 cases involving locked plate osteosynthesis (10.0% of all removals, 26.1% of all locked plate removals). The statistical analysis showed a significantly higher implant-related complication rate with locked plates compared to the conventional plates (p < 0.01). Hardware removal can be a complication-afflicted operation, especially cases involving locked-plate removal should only be performed if a strong indication is evident. Possible benefits of the procedure should be considered carefully, taking the cost-benefit ratio into account.

  11. Torque ultra difference fault analysis of flywheel bolt tightening machine%飞轮螺栓拧紧机力矩超差问题分析

    Institute of Scientific and Technical Information of China (English)

    李绍红

    2013-01-01

    对轿车发动机主装配线飞轮螺栓拧紧机力矩超差原因进行分析并排除故障.%In this paper, the main assembly line for car engine flywheel bolt tightening machine torque error cause is analyzed, and the troubleshooting process is described.

  12. 一种螺栓拉伸器校准方法研究%A Calibration Method Research for Bolt Tensioners

    Institute of Scientific and Technical Information of China (English)

    赵兴亮; 杨思凡; 李玮; 陈宝有

    2015-01-01

    A calibration method for bolt tensioners is presented. According to the theory of Newton's Third Law, the calibration device is researched and designed to calibrate the bolt tensioners. The meas-urement error and repeatability analysis and uncertainty evaluation show the linearity is good. Considering the measurement error is within ±1%, which meets the calibration requirements for bolt tensioners, the designed calibration device is capable to carry out the calibration work for bolt tensioners.%介绍了螺栓拉伸器的一种校准方法,运用牛顿第三定律的基本原理,研究并设计了一种拉伸器校准装置对螺栓拉伸器进行校准,通过对实验结果的误差和重复性分析,以及不确定度评定,表明该拉伸器校准装置具有良好的线性度,测量误差在±1%以内,符合螺栓拉伸器校准要求,达到了校准螺栓拉伸器的目的,可以开展螺栓拉伸器校准工作。

  13. Effect of tree species and end seal on attractiveness and utility of cut bolts to the redbay Ambrosia beetle and granulate Ambrosia beetle (Coleoptera: Curculionidae: Scolytinae)

    Science.gov (United States)

    Albert E. Mayfield; James L. Hanula

    2012-01-01

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is a non-native invasive pest and vector of the fungus that causes laurel wilt disease in certain trees of the family Lauraceae. This study assessed the relative attractiveness and suitability of cut bolts of several tree species to X. glabratus. In 2009, female X. glabratus were equally attracted to traps...

  14. 用于风电机组的新型螺栓连接形式探究%Analysis of New Bolt Connection Forms for Wind Turbines

    Institute of Scientific and Technical Information of China (English)

    关雪松; 万保库; 张芹

    2013-01-01

    In order to increase the reliability and load capacity of bolted connection and decrease the connection size, two methods of bolted connection used in wind turbine are proposed in this paper, one is to use friction shims to increase the friction coefcient between the interface, the other is to use the bolt enveloped with a hollow pin to increase the load capacity of connection. These two methods all can increase the load capacity of bolted connection that can provide the safe and reliable connection methods for wind turbine.%为了提高风电机组中螺栓连接的可靠性,提高螺栓连接的承载能力,并减小相应零部件的连接尺寸,本文提出了两种新型的风电机组螺栓连接形式:一种是采用摩擦片增加接触面摩擦系数;一种是采用销套螺栓的形式提高螺栓连接的抗剪切能力。这两种方法都可以有效地提高螺栓连接的承载能力,为风电机组提供安全可靠的连接方式。

  15. The ITER EC H&CD upper launcher: Design, analysis and testing of a bolted joint for the Blanket Shield Module

    NARCIS (Netherlands)

    Gessner, R.; Aiello, G.; Grossetti, G.; Meier, A.; Ronden, D.; Spaeh, P.; Scherer, T.; Schreck, S.; Strauss, D.; Vaccaro, A.

    2013-01-01

    The final design of the structural system for the ITER EC H&CD upper launcher is in progress. Many design features of the preliminary design are under revision with the aim to achieve the built-to-print-status. This paper deals with design and analysis of a bolted joint for the Blanket Shield Mo

  16. Localised Plate Motion on Venus

    Science.gov (United States)

    Ghail, R. C.

    1996-03-01

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

  17. Tectonics of the Easter plate

    Science.gov (United States)

    Engeln, J. F.; Stein, S.

    1984-01-01

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

  18. Tectonics of the Easter plate

    Science.gov (United States)

    Engeln, J. F.; Stein, S.

    1984-01-01

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

  19. A School Divided: One Elementary School's Response to Education Policy

    Science.gov (United States)

    Zoch, Melody

    2017-01-01

    This article examines how one elementary school was divided into two schools--a primary and an intermediate school--because of how policies were interpreted and enacted with regard to high-stakes testing. The grades in which students took high-stakes tests were privileged in terms of receiving monetary resources and support from staff. An emphasis…

  20. Nigeria united in grief; divided in response: Religious terrorism ...

    African Journals Online (AJOL)

    Nigeria united in grief; divided in response: Religious terrorism, Boko Haram, and the dynamics of state response. ... Boko Haram's avowed aim is to wrest control from the Nigerian government and to impose a strict form of Sharia law across a ...