Relevant bibliographies by topics / Pivots assembly

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers

Academic literature on the topic 'Pivots assembly'

Author: Grafiati
Published: 4 June 2021
Last updated: 8 February 2022

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Journal articles on the topic "Pivots assembly"

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Pflueger, Nathan. "Graph reductions, binary rank, and pivots in gene assembly." Discrete Applied Mathematics 159, no. 17 (October 2011): 2117–34. http://dx.doi.org/10.1016/j.dam.2011.07.007.

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Brijder, Robert, and Hendrik Jan Hoogeboom. "Maximal pivots on graphs with an application to gene assembly." Discrete Applied Mathematics 158, no. 18 (November 2010): 1977–85. http://dx.doi.org/10.1016/j.dam.2010.08.030.

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Lim, Jonas J. B., and Arthur G. Erdman. "Application of Type Synthesis Theory to the Redesign of a Complex Surgical Instrument." Journal of Biomechanical Engineering 124, no. 3 (May 21, 2002): 265–72. http://dx.doi.org/10.1115/1.1468635.

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Surgical instruments consist of basic mechanical components such as gears, links, pivots, sliders, etc., which are common in mechanical design. This paper describes the application of a method in the analysis and design of complex surgical instruments such as those employed in laparoscopic surgery. This is believed to be the first application of type synthesis theory to a complex medical instrument. Type synthesis is a methodology that can be applied during the conceptual phase of mechanical design. A handle assembly from a patented laparoscopic surgical stapler is used to illustrate the application of the design method developed. Type synthesis is applied on specific subsystems of the mechanism within the handle assembly where alternative design concepts are generated. Chosen concepts are then combined to form a new conceptual design for the handle assembly. The new handle assembly is improved because it has fewer number of parts, is a simpler design and is easier to assemble. Surgical instrument designers may use the methodology presented here to analyze the mechanical subsystems within complex instruments and to create new options that may offer improvements to the original design.
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Pigoski, T. M., and J. Duffy. "An Inverse Force Analysis of a Planar Two-Spring System." Journal of Mechanical Design 117, no. 4 (December 1, 1995): 548–53. http://dx.doi.org/10.1115/1.2826717.

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A closed-form inverse force analysis was performed on a planar two-spring system. The two springs were grounded to pivots at one end and attached to a common pivot at the other. A known force was applied to the common pivot of the system, and it was required to determine all of the assembly configurations. By variable elimination, a sixth degree polynomial in the resultant length of one spring was derived, and from this, six real solutions of the point of application of force were obtained. Following this, the applied force was incremented along a line and the six paths of the moving pivot were tracked starting from the zero-load configurations. An analysis of these results showed stability phenomena indicating the workspace of this system contained regions of negative spring stiffness and points of catastrophe.
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Kiener, Lionel, Hervé Saudan, Florent Cosandier, Gérald Perruchoud, and Peter Spanoudakis. "Innovative concept of compliant mechanisms made by additive manufacturing." MATEC Web of Conferences 304 (2019): 07002. http://dx.doi.org/10.1051/matecconf/201930407002.

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The complete redesign for Additive Manufacturing of compliant mechanism structures enables CSEM to develop innovative concepts to drastically reduce the need of machining and assembly after additive manufacturing. Support structures under flexure blades are thus minimised and the overall process becomes more streamlined. Moreover, this concept allows us to easily design and produce monolithic cross flexure pivots with interlocked flexible blades. Based on this concept, CSEM is now developing new architectures of Compliant Mechanisms based on Additive Manufacturing (COMAM) for the European Space Agency (ESA) in the frame of a GSTP research project. The past and current work of design, 3D printing and testing on several compliant mechanisms are presented. These demonstrators will be used as use-case for future high-precision and harsh environment applications such as cryogenic and space.
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Robinson, Graham C., Markus Kaufmann, Céline Roux, Jacobo Martinez-Font, Michael Hothorn, Stéphane Thore, and Teresa B. Fitzpatrick. "Crystal structure of the pseudoenzyme PDX1.2 in complex with its cognate enzyme PDX1.3: a total eclipse." Acta Crystallographica Section D Structural Biology 75, no. 4 (April 1, 2019): 400–415. http://dx.doi.org/10.1107/s2059798319002912.

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Pseudoenzymes have burst into the limelight recently as they provide another dimension to regulation of cellular protein activity. In the eudicot plant lineage, the pseudoenzyme PDX1.2 and its cognate enzyme PDX1.3 interact to regulate vitamin B6 biosynthesis. This partnership is important for plant fitness during environmental stress, in particular heat stress. PDX1.2 increases the catalytic activity of PDX1.3, with an overall increase in vitamin B6 biosynthesis. However, the mechanism by which this is achieved is not known. In this study, the Arabidopsis thaliana PDX1.2–PDX1.3 complex was crystallized in the absence and presence of ligands, and attempts were made to solve the X-ray structures. Three PDX1.2–PDX1.3 complex structures are presented: the PDX1.2–PDX1.3 complex as isolated, PDX1.2–PDX1.3-intermediate (in the presence of substrates) and a catalytically inactive complex, PDX1.2–PDX1.3-K97A. Data were also collected from a crystal of a selenomethionine-substituted complex, PDX1.2–PDX1.3-SeMet. In all cases the protein complexes assemble as dodecamers, similar to the recently reported individual PDX1.3 homomer. Intriguingly, the crystals of the protein complex are statistically disordered owing to the high degree of structural similarity of the individual PDX1 proteins, such that the resulting configuration is a composite of both proteins. Despite the differential methionine content, selenomethionine substitution of the PDX1.2–PDX1.3 complex did not resolve the problem. Furthermore, a comparison of the catalytically competent complex with a noncatalytic complex did not facilitate the resolution of the individual proteins. Interestingly, another catalytic lysine in PDX1.3 (Lys165) that pivots between the two active sites in PDX1 (P1 and P2), and the corresponding glutamine (Gln169) in PDX1.2, point towards P1, which is distinctive to the initial priming for catalytic action. This state was previously only observed upon trapping PDX1.3 in a catalytically operational state, as Lys165 points towards P2 in the resting state. Overall, the study shows that the integration of PDX1.2 into a heteromeric dodecamer assembly with PDX1.3 does not cause a major structural deviation from the overall architecture of the homomeric complex. Nonetheless, the structure of the PDX1.2–PDX1.3 complex highlights enhanced flexibility in key catalytic regions for the initial steps of vitamin B6 biosynthesis. This report highlights what may be an intrinsic limitation of X-ray crystallography in the structural investigation of pseudoenzymes.
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Krajewski, Casimir, Randolph I. Melville, and William W. Porter. "Pivot bushing assembly application." Journal of the Acoustical Society of America 86, no. 1 (July 1989): 452. http://dx.doi.org/10.1121/1.398247.

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Garner, Brian A., Jaeho Shim, and Scott Wilson. "An Apparatus and Protocol to Measure Shoulder Girdle Strength." Journal of Medical Devices 1, no. 4 (August 10, 2007): 246–53. http://dx.doi.org/10.1115/1.2796190.

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Muscles actuating the shoulder girdle are important for stabilizing the scapula and coordinating phased kinematics of the shoulder complex. If these muscles become weak or imbalanced, joint instability and injury may result. Reliable measurement of shoulder strength is thus important for prevention, diagnosis, and rehabilitation of shoulder problems. To date, studies quantifying the strength of the shoulder girdle are limited. The purpose of this work was to design and evaluate a custom apparatus and corresponding protocol for measuring maximal, voluntary, isometric strength of the shoulder girdle during various forms of shrugging exercise. A custom apparatus was constructed as a rigid frame with a vertical post supporting a seat, seat back, and horizontal beam. The beam extends laterally on either side beyond and around the shoulders of a seated subject. A pair of arm extension members pivots on the beam about an axis aligned with the shoulder flexion-extension axis. These members can be locked in place at any angle. Between them is mounted a force-sensing grip assembly, which can be adjusted proximally or distally to accommodate varying shoulder girdle positions. Subjects grasp the grip assembly handles with extended elbows and push or pull as forcefully as possible. Nine female and ten male subjects participated in a protocol using the apparatus to measure maximum isometric force generated at three positions each for elevation, depression, protraction, and retraction of the shoulder girdle (3positions×4modes=12tests). A video motion capture system was used to measure shoulder girdle angles. The reliability of the approach was evaluated based on the repeatability of measured shoulder elevation angle, protraction angle, and total force over three days of testing. The apparatus performed well during the tests, providing a stable, rigid, yet adjustable platform for measuring shoulder girdle strength. Repeatability of force measurements was interpreted as very good to excellent, with intraclass correlation coefficient (ICC) (2,1) values ranging from 0.83 to 0.95 for all tests except one (ICC=0.79). Repeatability of angle measurements was interpreted as good to excellent. For tests measuring elevation and depression strength, the ICC of elevation angle ranged from 0.85 to 0.89. For tests measuring protraction and retraction strength, the ICC of protraction angle ranged from 0.68 to 0.88. This type of apparatus could be an effective clinical tool for measuring strength in the shoulder girdle muscles. Use of the video motion capture system is optional.
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Hahn, Hyunggu, Sang Ho Park, Hyun-Jung Kim, Sunghoon Kim, and Byung Woo Han. "The DRS–AIMP2–EPRS subcomplex acts as a pivot in the multi-tRNA synthetase complex." IUCrJ 6, no. 5 (August 24, 2019): 958–67. http://dx.doi.org/10.1107/s2052252519010790.

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Aminoacyl-tRNA synthetases (ARSs) play essential roles in protein biosynthesis as well as in other cellular processes, often using evolutionarily acquired domains. For possible cooperativity and synergistic effects, nine ARSs assemble into the multi-tRNA synthetase complex (MSC) with three scaffold proteins: aminoacyl-tRNA synthetase complex-interacting multifunctional proteins 1, 2 and 3 (AIMP1, AIMP2 and AIMP3). X-ray crystallographic methods were implemented in order to determine the structure of a ternary subcomplex of the MSC comprising aspartyl-tRNA synthetase (DRS) and two glutathione S-transferase (GST) domains from AIMP2 and glutamyl-prolyl-tRNA synthetase (AIMP2GST and EPRSGST, respectively). While AIMP2GST and EPRSGST interact via conventional GST heterodimerization, DRS strongly interacts with AIMP2GST via hydrogen bonds between the α7–β9 loop of DRS and the β2–α2 loop of AIMP2GST, where Ser156 of AIMP2GST is essential for the assembly. Structural analyses of DRS–AIMP2GST–EPRSGST reveal its pivotal architecture in the MSC and provide valuable insights into the overall assembly and conditionally required disassembly of the MSC.
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Choodoung, Sakkarin, and Uttapol Smutkupt. "Analysis Design for Assembly by MTM-2 (Methods Time Measurement-2) for Wood Joints in Furniture." Advanced Materials Research 566 (September 2012): 394–98. http://dx.doi.org/10.4028/www.scientific.net/amr.566.394.

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This research study assembly process of a study of Wood Joints with Motion Time Study MTM-2 (Methods Time Measurement-2) and DFA (Design for Assembly) an assessment of the ability to assembly in the Feeding and Fitting. with LUCAS Assembly Evaluation Method for the results of the assessment and find the good-bad points of the assessment was applied. Wood Joint Index for this analysis is the feeding and fitting should not exceed 2.5 The pivot of the three groups in terms of feeding Index did not exceed 2.5 The advantages of the assessments, when applied to the wood. In general, the nature of Wood Joints must rely on to tool help in almost all assemble of the joints. Each tool is the difficulty of performing it. And in the Entrance of the parts are in a bad score. Tolerance in the 0.2 to 0.3 mm at the Wood Joint this is limitation is that the scores of these problems. So both of these topics for Wood Joints may be more table to the assessment more accurate and led to the development process for next time.
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Dissertations / Theses on the topic "Pivots assembly"

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Kočiš, Petr. "Orientační ústrojí průmyslových robotů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231675.

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The diploma thesis deals with an orientation mechanism of industrial robots for mounting of pivots and screws into the mounting holes. In the first phase there is a research of inventions mainly realized in the United States Patent and Trademark Office database. Subsequently the conditions of the assembly are solved. On the base of the conditions the functional requirements are described. The diploma thesis includes seven conceptual variants, which are proposed as a 3D design. Using the basical multi-criteria method the best conceptual variant is specified. That is specified due to the accepted criterias. In the next part of the diploma thesis there is a calculation, that comprises this technically and economically most promising conceptual variant. The calculation consists of a statics, a kinematics and a dynamics of the propel, a stenght control of the mechanism and kinematics analysis of the whole mechanism. Results of the calculation are used by the detailed design of orientation mechanism, that also comprises technological production theory and a correct assembly. Economical analysis, which comprises cost of produce of this newly developed automation equipment, is worked up in the conclusion of the diploma thesis. The diploma thesis also comprises drawings. The variant solves a new conception, which can be patented as an utility model.
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Books on the topic "Pivots assembly"

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Dame Rosalyn, DBE, QC, Higgins, Webb Philippa, Akande Dapo, Sivakumaran Sandesh, and Sloan James. Part 3 The United Nations: What it Does, 24 Protecting the Environment. Oxford University Press, 2017. http://dx.doi.org/10.1093/law/9780198808312.003.0024.

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The United Nations (UN) has taken action to protect the environment despite the absence of any explicit mention of the environment or its protection in the UN Charter. The UN has ‘played a pivotal role as a framework for developing environmental decision-making’. It has also ‘contributed to many of the principles of environmental law’, including the polluter-pays principle, the notion of common differentiated responsibilities, and the precautionary principle. This chapter discusses the work of the principal organs, including the General Assembly, Security Council, Economic and Social Council, and International Court of Justice; the work of the specialized agencies; institutional arrangements of multilateral environmental agreements; and the United Nations Environment Programme.
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Book chapters on the topic "Pivots assembly"

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Pellegrin-Romeggio, Frédéric, and Diego Vega. "Combination as the Key Competence for the Dynamic Assembly of Temporary Networks: The Role of the Pivot-Assembler." In A Focused Issue onBuilding New Competences in Dynamic Environments, 61–83. Emerald Group Publishing Limited, 2014. http://dx.doi.org/10.1108/s1744-211720140000007003.

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Erakat, Noura. "The UN Statehood Bid." In Land of Blue Helmets. University of California Press, 2016. http://dx.doi.org/10.1525/california/9780520286931.003.0005.

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This chapter focuses on the United Nations's Palestinian “statehood” bid starting in 2011. In May 2011, the Palestine Liberation Organization (PLO)/Palestinian Authority (PA) announced that it would seek membership as a state within the UN. The UN statehood bid would alter the PLO's status as a nonmember observer entity, conferred upon it by the UN General Assembly in 1974. While the benefits of UN membership, or in the alternative, a UN upgrade, are manifold, none of them guarantee Palestinian self-determination or freedom from Israeli control. The chapter suggests that this statehood bid could have been a pivot away from complete reliance on the United States to deliver independence and a return to multilateralism that positioned the world superpower as part of the problem rather than the solution. However, the promise of multilateralism, signaled by Palestinians in 2011, has not been realized. The Palestinian leadership has responded to the ever-diminishing potential of the US-brokered peace process with incremental steps into international forums.
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Halperin, Ehud. "Assembling the Ritual Core." In The Many Faces of a Himalayan Goddess, 37–84. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190913588.003.0003.

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This chapter presents the vivid core of the ritual embodiment of the goddess Haḍimbā, namely her rath, a palanquin-like structure carried on devotees’ shoulders. It is through the movements of this ritual vehicle and the accompanying sessions of oracular possession that the goddess manifests and interacts with her devotees. Haḍimbā is revealed in these performances as an assembled entity, whose cognition and knowledge are distributed in networks of humans, objects, and environments, and whose actions are shaped in ritual arenas. Furthermore, the ritual encounters of her rath with those of other village deities integrate Haḍimbā into the regional web of ritual associations and establish her as a representative of her community. These rituals thus contribute to social formations of Haḍimbā’s community of followers, and she herself is established in them as a complex social agent who is pivotal to both communal stability and change.
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Heim, Michael. "Interactive Design : Tunnel or Spiral." In Virtual Realism. Oxford University Press, 1998. http://dx.doi.org/10.1093/oso/9780195104264.003.0009.

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Interactivity pounds at the doors of all broadcast media. Newspapers publish daily reports about cyberspace, then invite readers to subscribe to their online news services. Television programs encourage on-air feedback via email. Movies and popular television shows maintain viewer newsgroups and offer World Wide Web sites with click-on audio and video. As the era of one-way messages fades, the tone of unilateral broadcasting sinks to the trashy low-end of media culture. Quality switches from the TV remote controls to the computer console. Programming ceases to be unilateral when interactivity arrives. Digital switching is, of course, under the hood of interactivity. The computer establishes a reciprocal relationship between sender and receiver, viewer and producer. Because computers handle high-speed transmission to-and-fro, the separating line between sender and receiver, viewer and producer, begins to blur. The digital switch converts text, sounds, and video to transmissible bits. And bits produce incoherent fragments that are hardly distinguishable from cultural noise. The blast of information shatters what remains of cultural coherence in the wobbling worlds of print and film distribution. The digital era splatters attention spans till the shared sensibility dribbles into fragmentary, disintegrative de-construction. Interactivity signals a process of reconstruction. The digital Humpty-Dumpty needs mending. Reconstruction is a process of designing wholes, virtual worlds, that are both received and actively assembled —full, rich experiential places fit for human habitation. From the bits of the digital era arises the holism of virtual design. Virtual design means building worlds from digital fragments, engineering usable software environments from disparate information sources. Worlds are not simply re-packaged fragments. Nor do virtual worlds re-present the primary physical world. What emerges are new functional wholes, habitats that emulate the engagement of real worlds. Software engineering and software architecture support these virtual worlds, but artists with traditional skills must play a pivotal role in their construction. Virtual architecture must go well beyond wire-frame models set in clean Cartesian coordinates. Polygons in Renaissance perspective are only the first steps of interactive design. Worlds require mood-tuned scenarios that draw on traditional artistic insights.
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Conference papers on the topic "Pivots assembly"

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Pigoski, Thomas M., and Joseph Duffy. "An Inverse Force Analysis of a Planar Two-Spring System." In ASME 1994 Design Technical Conferences collocated with the ASME 1994 International Computers in Engineering Conference and Exhibition and the ASME 1994 8th Annual Database Symposium. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/detc1994-0218.

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Abstract A closed-form inverse force analysis was performed on a planar two-spring system. The two springs were grounded to pivots at one end and attached to a common pivot at the other. A known force was applied to the common pivot of the system, and it was required to determine all of the assembly configurations. By variable elimination, a sixth degree polynomial in the resultant length of one spring was derived, and from this, six real solutions of the point of application of force were obtained. Following this, the applied force was incremented along a line and the six paths of the moving pivot were tracked starting from the zero-load configurations. An analysis of these results showed stability phenomena indicating the workspace of this system contained regions of negative spring stiffness and points of catastrophe.
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Coghlan, David M., and Dara W. Childs. "Characteristics of a Spherical Seat TPJB With Four Methods of Directed Lubrication: Part 2 — Rotordynamic Performance." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-42336.

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Measured and predicted rotordynamic characteristics are presented for a 4-pad, spherical-seat, TPJB with 0.5 pivot offset, 0.6 L/D, 101.6 mm nominal diameter, and 0.3 preload in the load-between-pivots orientation. One bearing is tested four separate times in the following four different lubrication configurations: (1) flooded single-orifice (SO) at the bearing shell, (2) evacuated leading edge groove (LEG), (3) evacuated spray-bar blocker (SBB), and (4) evacuated spray-bar (SB). The same set of pads is used for every test to maintain clearance and preload; each method of lubrication is added as an assembly to the bearing. Test conditions include surface speeds and unit loads up to 85 m/s and 2.9 MPa respectively. Dynamic data includes four sets (one set for each bearing configuration) of direct and cross-coupled rotordynamic coefficients derived from measurements and fit to a frequency independent KCM model. The pivot stiffness (pad and pivot in series) is measured and incorporated into predictions.
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Coghlan, David M., and Dara W. Childs. "Characteristics of a Spherical Seat TPJB With Four Methods of Directed Lubrication: Part 1 — Thermal and Static Performance." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-42331.

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Static and thermal characteristics (measured and predicted) are presented for a 4-pad, spherical-seat, TPJB with 0.5 pivot offset, 0.6 L/D, 101.6 mm nominal diameter, and 0.3 preload in the load-between-pivots orientation. One bearing is tested four separate times in the following four different lubrication configurations: (1) flooded single-orifice (SO) at the bearing shell, (2) evacuated leading edge groove (LEG), (3) evacuated spray-bar blocker (SBB), and (4) evacuated spray-bar (SB). The LEG, SBB, and SB are all considered methods of “directed lubrication”. These methods rely on lubrication injected directly to the pad/rotor interface. The same set of pads is used for every test to maintain clearance and preload; each method of lubrication is added as an assembly to the bearing. Test conditions include surface speeds and unit loads up to 85 m/s and 2.9 MPa respectively. Static data includes rotor-bearing eccentricities, and attitude angles. Thermal data include measured temperatures from sixteen bearing thermocouples. Twelve of the bearing thermocouples are embedded in the babbitt layer of the pads while the remaining four are oriented at the leading and trailing edge of the loaded pads exposed to the lubricant. Bearing thermocouples provide a circumferential and axial temperature gradient. The pivot stiffness (pad and pivot in series) is measured and incorporated into predictions.
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Hanchak, Michael S., and Andrew P. Murray. "Kinematic Synthesis of Binary Actuated Mechanisms for Rigid Body Guidance." In ASME 2000 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/detc2000/mech-14072.

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Abstract This paper presents a method for designing mechanisms composed of Revolute-Binary state prismatic-Revolute (RBR) chains for rigid body guidance. Where a prismatic joint allows for any distance between two revolute joints, a binary state prismatic joint reaches two distances precisely. A single RBR chain can be designed to reach six positions. A parallel arrangement of three RBR chains can be assembled at the six positions but, in general, is not a viable kinematic solution. By requiring the arrangement of three RBR chains to share specific fixed and moving pivots, called an N-type arrangement, four positions are reachable. Further, the design space is quickly searchable for singularity-free solutions. Examples illustrate a solution to a four position synthesis problem and a ten position problem using a serial assembly of these mechanisms.
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Cao, Jianming, Tim Dimond, and Paul Allaire. "Nonlinear Modeling of Tilting-Pad Bearings With Application to a Flexible Rotor Analysis." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-13712.

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Tilting-pad bearings are widely used in high-speed rotating machines to improve the system’s stability. Linearized static or dynamic stiffness and damping coefficients are often applied to rotordynamic analyses. This method has limits due to the nonlinear effects of tilting-pad bearing under severe unbalance conditions or large shaft vibration. This work presents a new modeling and assembly method of a linear flexible rotor with nonlinear tilting-pad bearings. The pressure profile on each pad is calculated using an approximate finite element method by solving Reynolds equation derived from a nonlinear tilting-pad bearing model. Nonlinear bearing forces are calculated based upon the shaft instantaneous position and velocity with an update at each time step. Effects of the bearing pad&pivot are evaluated first by applying a rigid rotor on tilting-pad bearings first. The nonlinear transient behavior of a flexible eight-stage compressor supported on two tilting-pad bearings is investigated. The nonlinear numerical transient response of the system under severe unbalance conditions, including coupled motions of bearing pads, bearing pivots and the shaft, and nonlinear bearing forces, is solved using a 4th order Runge-Kutta integration after assembling the system together. Under severe unbalance conditions. Sub and super harmonic response is shown to exist from both rotor and bearing components.
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San Andrés, Luis, and Yujiao Tao. "The Role of Pivot Stiffness on the Dynamic Force Coefficients of Tilting Pad Journal Bearings." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-94403.

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Recent comprehensive experimental data showcasing the force coefficients of commercial size tilting pad journal bearings has brought to rest the long standing issue on the adequacy of the [K,C,M] physical model to represent frequency independent bearing force coefficients, in particular viscous damping. Most experimental works test TPJBs with large preloads, operating over a large wide range of rotor speeds, and with null to beyond normal specific loads. Predictions from apparently simple fluid film bearing models stand poor against the test data which invariably signals to theory missing pivot and pad flexibility effects, and most importantly, ignoring significant differences in bearing and pad clearances due to actual operation, poor installation and test procedures, or simply errors in manufacturing and assembly. Presently, a conventional thermo hydrodynamic bulk flow model for prediction of the pressure and temperature fields in TPJBs is detailed. The model accounts for various pivot stiffness types, all load dependent and best when known empirically, and allows for dissimilar pad and bearing clearances. The algorithm, reliable even for very soft pad-pivots, predicts frequency reduced bearing impedance coefficients and, over a certain frequency range, delivers the bearing stiffness, damping and virtual mass force coefficients. Good correlation of predictions against a number of experimental results available in the literature bridges the gap between a theoretical model and the applications. Predicted pad reaction loads reveal large pivot deflections, in particular for a bearing with large preloaded pads, with significant differences in pivot stiffness as a function of specific load and operating speed. The question on how pivot stiffness acts to increase (or decrease) the bearing force coefficients, in particular the dynamic stiffness vs. frequency, remains since the various experimental data show contradictory results. A predictive study with one of the test bearings varies its pivot stiffness from 10% of the fluid film stiffness to an almost rigid one, 100 times larger. With certainty, bearings with nearly rigid pivot stiffness show frequency independent force coefficients. However, for a range of pad pivot stiffness, 1/10 to ten times the fluid film stiffness, TPJB impedances vary dramatically with frequency, in particular as the excitation frequency grows above synchronous speed. The bearing virtual mass coefficients become negative, thus stiffening the bearing for most excitation frequencies.
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Miller, David J., and Milo V. Kral. "The Selection and Testing of Compression Seal and Chamber Coating Materials for the Pivotal™ Engine." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-64379.

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The Pivotal™ Engine was conceived by Pivotal Engineering LTD to overcome some of the inherent problems associated with a conventional two-cycle engine, such as high wear rates and friction losses due to piston tilt and large port openings, reliability problems due to lack of control over piston temperatures and high oil consumption. The Pivotal engine is an Otto cycle two-stroke engine. The engine is assembled from 500cc modules utilizing a rectangular piston that pivots on a plain bearing at one end. The pivoting motion of the piston allows coolant to enter the piston through the centre of the pivot giving temperature control of the combustion chamber while restraining the piston so it has little or no contact with the chamber walls. Although friction loss, temperature control and oil consumption problems have thus been mitigated, prototype engines still experienced problems with high compression seal wear rates. Compression seals run in a reciprocating motion along a flat chamber wall, somewhat analogous to piston rings in a conventional engine, although velocity varies along the seal length. The goal of this research is therefore to select and test compression seals materials to obtain an adequate working life in the Pivotal engine. Based on the rotational tribometer results, the most promising chamber coating so far is plasma sprayed iron with molybdenum and the most promising seal material is reaction bonded silicon nitride.
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Homrossukon, S., and N. Tripetchipetchpisal. "Process and Product Quality Improvement of Pivot Assembly Process." In 2019 IEEE 6th International Conference on Industrial Engineering and Applications (ICIEA). IEEE, 2019. http://dx.doi.org/10.1109/iea.2019.8714996.

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Gendreau, Dominique, Abdenbi Mohand-Ousaid, Patrick Rougeot, Philippe Lutz, and Micky Rakotondrabe. "Additive manufacturing: Design of a basic pivot articulation actuated with SMA wire." In 2016 IEEE International Symposium on Assembly and Manufacturing (ISAM). IEEE, 2016. http://dx.doi.org/10.1109/isam.2016.7750713.

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10

Zeng, Hongjun, Alan Feinerman, and Zhiliang Wan. "A Compact, Easily Assembled Micromirror With Liquid Metal Pivot." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-41528.

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Abstract:
We have developed a new approach to achieve a high-speed micromirror, which can rapidly tilt large angles with a low voltage and a compact footprint. In our approach we use a liquid metal drop with a low vapor pressure as the pivot, and the micromirror is tilted by an electrostatic torque. Micromirrors (1 mm x 1 mm) and the actuating circuit are microfabricated with a centralized wetting area surrounded by a non-wetting Parylene area to confine the drop. The frequency response curve shows that the mirror has 78V snap-down voltage and resonant frequency at 165Hz, and has a potential resonant frequency more than 3k Hz if the size of the mirror and liquid metal pivot is reduced. A micromirror with a liquid metal pivot is expected to have significantly higher reliability since a liquid drop does not suffer from mechanical fatigue. Due to the single point support, the micromirror can be tilted in an arbitrary direction, and the fabrication process is simpler than those required to create solid torsional weak links.
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