Bibliografías temáticas / Active fixtures

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Literatura académica sobre el tema "Active fixtures"

Autor: Grafiati

Publicado: 10 de marzo de 2023

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Artículos de revistas sobre el tema "Active fixtures"

MÖHRING, H. Christian, Werner GESSLER, Alexander KÖNIG, Le Trung NGUYEN y Q. Phuc NGUYEN. "Modular intelligent fixture system for flexible clamping of large parts". Journal of Machine Engineering 4, n.º 17 (12 de diciembre de 2017): 29–39. http://dx.doi.org/10.5604/01.3001.0010.7003.

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In this work a modular intelligent fixture system for flexible clamping of large parts is presented. The fixture modules consist of a hybrid material structure involving metal frame elements and mineral casting. These modules can be combined and connected to realize fixtures adapted to the geometry of the workpiece and requirements of the machining processes. By integrated pipes and interfaces, an internal hydraulic supply and active cooling is possible even for combined modules. Temperature and acceleration sensors allow for an active thermal control and process monitoring. The modules and first test fixtures are investigated in experiments.

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Chitariu, Dragoş-Florin y Adriana Munteanu. "Research on 3D printed fixture components". MATEC Web of Conferences 178 (2018): 02008. http://dx.doi.org/10.1051/matecconf/201817802008.

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Fixtures are used for orientation, positioning and tightening of the workpiece during machining, control and assembly. The main fixture requirements are: orientation, positioning and tightening precision in accordance with the machining requirements. The materials used for fixture components, especially, supports and clamping mechanism are, usually, alloy steel with HRC hardness up to 55-60 HRC. These components are machined to high level of precision thus assuring the overall precision of the fixture. In order to achieve high stiffness and a good dampening capacity the fixture become, usually, very heavy. In the case of manually operated fixtures light weight is an advantage; also there are operations such as inspection, assembly where the operating forces are low. In this case lightweight materials can be used for fixture construction. In this paper the FDM (Fused Deposition Modeling) 3D printing technology is used. Support buttons and v-block fixture components were selected and 3D printed. The effect of printing orientation of active surfaces of support was analysed. The dimensional accuracy and surface roughness on the active surface were measured. Experimental results indicate that surface roughness is dependent on the orientation of the printed workpiece.

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Bowyer, Stuart A., Brian L. Davies y Ferdinando Rodriguez y Baena. "Active Constraints/Virtual Fixtures: A Survey". IEEE Transactions on Robotics 30, n.º 1 (febrero de 2014): 138–57. http://dx.doi.org/10.1109/tro.2013.2283410.

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Cruz-Ramírez, S. Rolando, Tatsuo Arai, Yasushi Mae, Tomohito Takubo y Kenichi Ohara. "Recognition and Removal of Interior Facilities by Vision-Based Robot System". Journal of Robotics and Mechatronics 22, n.º 1 (20 de febrero de 2010): 50–64. http://dx.doi.org/10.20965/jrm.2010.p0050.

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For future dismantling jobs in the renovation of the interiors of office buildings, we propose a robotic dismantling system that will assist human workers with the hard works. As an application of the robotic system, this paper presents the process of removing ceiling fixtures, such as Lamp Panels (LPs) and Air Conditioning Vents (ACVs), by man and robot. In this collaboration, a robot arm provides assistance by holding and collecting the fixtures, and the human worker only removes screws and/or nuts. In order to lead the robot to a holding position, the human worker indicates a position on the fixture to the robot with brief and simple instructions. The robot estimates the pose of the fixture through 3D model-based object recognition with a hand-mounted stereo camera. The integration of multiple viewpoints for the robot with an active lighting system enhances the recognition performance against both natural lighting changes at the site and the variability in the pose between the camera and the object to be recognized. As a verification experiment, the sequential removal of several different ceiling fixtures is presented. In this experiment, robust recognition is achieved with an average accuracy of 10 mm. The feasibility of the system is verified by using the completion time and the precision requirements in a practical environment.

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Townes, Maryanne. "Jigs and Fixtures: Design Review Guidelines for the Ergonomics Engineer". Proceedings of the Human Factors and Ergonomics Society Annual Meeting 38, n.º 15 (octubre de 1994): 960. http://dx.doi.org/10.1177/154193129403801532.

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Traditionally, the ergonomics engineer has not played an active role in the design of jigs and fixtures used to manually assemble parts. This is problematic, since tool redesigns are often infeasible due to cost and production constraints. Therefore, less effective measures must be used to control ergonomic hazards, since the hazard(s) cannot be engineered out during the design process. References, guidelines and checklists used by many tool designers do not include ergonomic engineering principles and methods. In addition, many ergonomics engineers may not be schooled in the elements of jig and fixture design, which may reduce their effectiveness as part of the tool design team. The purpose of this paper is to provide the ergonomics engineer with an overview of the design process, and proffer guidelines to assist in the review of jig and fixture designs.

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Sallese, Lorenzo, Niccolò Grossi, Jason Tsahalis, Antonio Scippa y Gianni Campatelli. "Intelligent Fixtures for Active Chatter Control in Milling". Procedia CIRP 55 (2016): 176–81. http://dx.doi.org/10.1016/j.procir.2016.08.019.

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Dehtiarov, Ivan, Anna Neshta, Illia Kosov y Yaroslav Klok. "EXPERIMENTAL RESEARCH OF THE RIGIDITY OF FIXTURES WITH INCOMPLETE LOCATION FOR CONNECTING ROD TYPE PARTS". Technical Sciences and Technologies, n.º 3(29) (2022): 15–26. http://dx.doi.org/10.25140/2411-5363-2022-3(29)-15-26.

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The use of modern machining centers with wide technological capabilities and the active development of productions with a small-scale form of organization necessitates an increase in the efficiency of fixtures capable of ensuring sufficient accuracy of machining with minimal costs.Classical approaches to the design of fixtures do not always allow machining with one installation with high-performance cutting conditions, so it is necessary to move the new approaches that allow maximum tool availability, which is important for the competitiveness of enterprises.The analysis of research and publications on numerical modeling and experimental research on the processing of parts of a complex shape that have insufficient rigidity showed that the issues of static research of the stress-deformation state of fixtures with incomplete locating have received little attention in the scientific literature.The purpose of the article is to experimentally demonstrate the possibility of machining non-separable connecting rods in machine tools with incomplete basing and fastening only on unprocessed surfaces in one installation with the achievement of all the necessary indicators of dimensional accuracy.The work presents for the first time an improved fixture with an incomplete location for machining connecting rod-type parts, and experimental studies of its stress-strain state in static mode are performed. The determined values of stresses and displacements compared with the previously proposed machine tool showed its technical advantage in bearing capacity for loads acting during machining.In this work, it was experimentally proven for the first time that the design of the improved fixture for machining connecting rods is capable of providing the necessary machining accuracy under static load and at the same time has a margin of accuracy thatexceeds the value of deformations by 1.5...2.5 times. The presented results and the positive experience of manufacturing a sample of a fixture can be used for its further research in a dynamic mode directly during machining, as well as for the design of technological equipment for parts of other classes, using an approach that involves incomplete locating of the workpiece

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Sallese, Lorenzo, Niccolò Grossi, Antonio Scippa y Gianni Campatelli. "Numerical investigation of chatter suppression in milling using active fixtures in open-loop control". Journal of Vibration and Control 24, n.º 9 (14 de septiembre de 2016): 1757–73. http://dx.doi.org/10.1177/1077546316668686.

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Among the chatter suppression techniques in milling, active fixtures seem to be the most industrially oriented, mainly because these devices could be directly retrofittable to a variety of machine tools. The actual performances strongly depend on fixture design and the control logic employed. The usual approach in the literature, derived from general active vibration control applications, is based on the employment of adaptive closed-loop controls aimed at mitigating the amplitude of chatter frequencies with targeted counteracting vibrations. Whilst this approach has proven its effectiveness, a general application would demand a wide actuation bandwidth that is practically impeded by inertial forces and actuator-related issues. This paper presents the study of the performance of alternative open-loop actuation strategies in suppressing chatter phenomena, aiming at limiting the required actuation bandwidth. A dedicated time-domain simulation model, integrating fixture dynamics and the features of piezoelectric actuators, is developed and experimentally validated in order to be used as a testing environment to assess the effectiveness of the proposed actuation strategies. An extensive numerical investigation is then carried out to highlight the most influential factors in assessing the capability of suppressing chatter vibrations. The results clearly demonstrated that the regenerative effect could be effectively disrupted by actuation frequencies close to half the tooth-pass frequency, as long as adequate displacement is provided by the actuators. This could sensibly increase the critical axial depth of cut and hence improve the achievable material removal rate, as discussed in the paper.

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Papastathis, T., O. Bakker, S. Ratchev y A. Popov. "Design Methodology for Mechatronic Active Fixtures with Movable Clamps". Procedia CIRP 3 (2012): 323–28. http://dx.doi.org/10.1016/j.procir.2012.07.056.

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Sallese, Lorenzo, Antonio Scippa, Niccolò Grossi y Gianni Campatelli. "Investigating Actuation Strategies in Active Fixtures for Chatter Suppression". Procedia CIRP 46 (2016): 311–14. http://dx.doi.org/10.1016/j.procir.2016.04.073.

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Tesis sobre el tema "Active fixtures"

Bakker, Otto Jan. "Control methodology and modelling of active fixtures". Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11734/.

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Fixtures are used to fixate, position and support workpieces, and are critical elements in manufacturing processes. Machining is one of these manufacturing processes, and this is often done by computer numerical control (CNC) machines. A major trend observed in production industry is that manufacturing is increasingly done in small batches in combination with a quick changeover from one product to another, in combination with a surge in automation. Several novel fixture concepts have been developed that allow for a reconfiguration of the fixture layout, such that different types of workpieces can be fixtured using the same fixture components. However, the initial novel fixturing concepts lacked accuracy, and, in addition, required long set-up times. Recently, a new fixturing concept has been developed, the so-called intelligent fixturing system. Sensors and actuators are integrated in an intelligent fixturing system, which allows for an automatic and precise reconfiguration of the fixturing elements. Additionally, the actuated fixture elements can be used to exert optimal clamping forces to minimise the workpiece deflection during the machining process, this is called active fixturing. A literature survey has been carried out, in which it has been established that the main process variables to control in active fixturing, are the reaction forces at the contacts where the workpiece is fixated and supported by the fixture (the locating points), and/or the part or fixture displacements. Furthermore, four knowledge gaps were identified: (1) a lack of computationally efficient models of workpiece response during machining; (2) a lack of methodic structural analysis approach of part-fixture interaction; (3) a lack of model-based control design, which can potentially speed up the fixture design process; and (4) a lack of control design methodology for active fixturing systems. An active fixturing system can be divided into the following subsystems: the part, the part-fixture contact interface, passive fixture elements, the actuated clamp, sensors and the controller(s). In the thesis, a methodical research approach has been applied to address the knowledge gaps by analysing the active fixturing subsystems. In addition, a model-based control design methodology has been proposed. The research has aimed to establish mathematical models, or the necessary tools and methodology to build the subsystem models, and methods to connect the subsystem models into an overall model of the active fixturing system. On basis of the subsystem analyses, two simple, yet complete, active fixturing systems have been modelled. Parameter studies have been held to assess the performance of the control design. In addition, an industrial case study has been analysed, using the developed control design methodology. The study of the subsystems resulted in the comprehensive structural dynamic analysis of workpieces: a finite element model of the workpiece is built. Typically, finite element models contain too many degrees of freedom for real-time control applications. It was found that model reduction techniques can be used to reduce significantly the number of degrees of freedom. Methodologies for the selection of the degrees of freedom and for ensuring that the model reduction is accurate enough for practical use have been established. Mathematical models for hydraulically and electromechanically actuated clamps have been established. Compensators for closed-loop servo-control of the clamps have been investigated and control strategies to maintain workholding stability are found. Finally, a methodology to establish the overall model of an active fixturing system has been implemented. The control design methodology, and the mathematical tools established in the thesis have been verified against case studies of simple active fixturing systems. Furthermore, from the industrial case study it is concluded that the control design methodology can be successfully applied on complex fixturing systems. Additionally, a mathematical model for a piezoelectrically actuated clamp was derived, which also demonstrates the general applicability of the control design methodology derived here, as a new established actuator model is integrated in the control design. The overall conclusion, is hence that a good methodology for the model-based control design of active part-fixturing systems has been developed, which enables the engineer to speed up the design process of active fixturing systems.

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Papastathis, Thomas. "Modelling and design methodology for fully-active fixtures". Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12000/.

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Fixtures are devices designed to repeatedly and accurately locate the processed workpiece in a desired position and orientation, and securely hold it in the location throughout the manufacturing process. Fixtures are also charged with the task of supporting the workpiece to minimise deflection under the loads arising from the manufacturing process. As a result, fixtures have a large impact on the outcome of a manufacturing process, especially when the workpiece presents low rigidity. Traditionally, in manufacturing environments, where thin-walled components are produced, the utilised fixtures are dedicated solutions, designed for a specific workpiece geometry. However, in the recent decades, when the manufacturing philosophy has shifted towards mass customisation, there is a constant technological pull towards manufacturing equipment that exhibits high production rates and increased flexibility/reconfigurability, without any compromise in the quality of the end result. Therefore, fixtures have been the focal point of a plethora of research work, targeting mainly towards either more reconfigurable, or more intelligent/adaptive solutions. However, there have been no attempts so far to merge these two concepts to generate a new fixturing approach. Such an approach, referred to in this work as fully-active fixrturing, would have the added ability to reposition its elements and adapt the forces it exerts on-line, maximising the local support to the workpiece, and thus reducing vibration amplitude and elastic deformation. This results in a tighter adherence to the nominal dimensions of the machined profile and an improved surface-finish quality. This research work sets out to study the impact of such fixturing solutions, through developing suitable models which reflect the fixture-workpiece system behaviour, and a design methodology that can support and plan the operation of fully-active fixtures. The developed model is based on a finite elements representation of the workpiece, capturing the dynamic response of a thin-walled workpiece that is being subjected to distributed moving harmonic loads. At the same time, the workpiece is in contact with an active element that operates in closed-loop control. An electromechanical actuator is charged with the role of the active elements, and it is modelled via first-principle based equations. Two control strategies are examined experimentally to identify the best performing approach. The direct force/torque control strategy with a Proportional-Integral action compensator is found to lead to a system that responds faster. This control architecture is included in the model of the active elements of the fixture. The behaviour of the contact between the fixture and the workpiece is approximated via a combination of a spring and a damper. The overall model is assembled using the impedance coupling technique and has been verified by comparing its response with the time-domain response of an experimental set-up. The developed model serves as the backbone of the fully-active fixture design methodology. The latter is capable of establishing important fixturing parameters, such as the pattern of motion of the movable fixture element, the points on the surface of the workpiece that formulate the motion path of the fixture element, the time instant at which the element needs to change position, and the clamping forces the fixture needs to apply and maintain. The methodology is applied on a thin plate test case. Such a plate has been also used in a series of machining experiments, for which the fixturing parameters used are those that resulted from the test case. A very good quantitative agreement between both experiments and theory was observed, revealing the capabilities of the methodology itself and of the fully-active fixturing approach in general.

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SALLESE, LORENZO. "On the development of active fixtures for the mitigation of chatter vibrations in milling". Doctoral thesis, 2017. http://hdl.handle.net/2158/1081178.

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In the last decades, unstable vibrations originated in the milling process, often referred to as chatter vibrations, have collected the interest of several researches, mainly driven by the detrimental effect this phenomenon generates on productivity, surface finishing and tool wear. Although several approaches and techniques have been developed nowadays, their industrial application is still limited by the required expertise, time-consuming procedures or relevant interventions on the machine tool structures. This research is focused on the investigation and design of active fixtures to mitigate chatter vibrations in milling, considering that this kind of devices could represent an appealing industrial alternative, due to the fact that they can be directly retrofitted to different machine tools and applied to different machining operations. The aim of this thesis was to improve the performance of intelligent active fixtures by carefully addressing the specific design challenges, both in terms of mechanical design and control aspects. The main focus was put in extending the device bandwidth in accordance with the requirements of a general chatter mitigation application, where chatter frequencies can easily reach and exceed several kilohertz. In particular, specific design guidelines and simplified modeling strategies, aimed at supporting the definition of an adequate mechanical design, are presented and discussed along with the selection of suitable actuation devices capable of granting the needed reliability, even when operated at high frequencies in demanding dynamic applications. Moreover, this work presents the development of a novel control strategy aimed at exploiting low-frequency excitation to disrupt chatter vibrations, without requiring the further extension of the device bandwidth nor the preliminary system identification and modelling, as generally needed for renowned model-based control techniques.

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Capítulos de libros sobre el tema "Active fixtures"

Estévez, Alex, Germán Rodríguez y Kepa Ayesta. "Case Study 3.3: Active Fixtures for High Precision Positioning of Large Parts for the Windmill Sector". En Lecture Notes in Production Engineering, 167–80. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-45291-3_10.

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Yamaguchi, Tomomi, Naomichi Furushiro y Masahiro Higuchi. "Application of the Active Flexible Fixture to a Peg-in-hole Task". En Service Robotics and Mechatronics, 49–54. London: Springer London, 2010. http://dx.doi.org/10.1007/978-1-84882-694-6_9.

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Emmerson, Allison L. C. "Waste Management from Center to Suburb". En Life and Death in the Roman Suburb, 92–124. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198852759.003.0004.

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“Waste Management from Center to Suburb” investigates how one humble activity illuminates multi-faceted relationships between city and suburb. It begins by reconsidering the infamous “puticuli” of Rome’s Republican Esquiline, arguing that these were not—as has long been believed—mass graves that marked the zone as a nightmarish no man’s land. The fixtures uncovered in nineteenth-century excavations are better interpreted as public cesspits, one of many contemporaneous investments in urban infrastructure, installed in a busy and well-connected district outside the growing city’s first wall. The second section moves forward in time to the early Imperial period, exploring waste management at Pompeii and elsewhere. Drawing on the results of recent excavations, it contends that the garbage mounds commonly found in Italy’s suburbs were not abandoned deposits of unwanted materials, akin to modern landfills, but active sites in an intense economy of use, reuse, and recycling, in which suburbs played a key role.

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Yamaguchi, T., M. Higuchi y K. Nagai. "ASSEMBLY SYSTEM BY USING PROTOTYPE OF ACTIVE FLEXIBLE FIXTURE". En Mechatronics for Safety, Security and Dependability in a New Era, 125–28. Elsevier, 2007. http://dx.doi.org/10.1016/b978-008044963-0/50026-6.

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Witting, Christian. "12. Trespass to land". En Street on Torts, 308–21. Oxford University Press, 2021. http://dx.doi.org/10.1093/he/9780198865506.003.0012.

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This chapter examines the protection against interferences with land provided by tort law. Land in this context includes not only the surface of the land but areas above and below it as well as fixtures. The chapter explains that the action for trespass to land protects the interest of the claimant in having his land free from the unjustified physical intrusion of another, and thus protects (once again) possession rather than title as such. The chapter discusses the elements of trespass and describes the types of acts that constitute it. It considers also remedies available for defendants in trespass to land cases, which include injunctions, actions for the recovery of land, and damages.

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Michelman, Frank I. "Constitutional Fidelity: Of Courts, Citizens, and Time". En Constitutional Essentials, 71—C5.N58. Oxford University PressNew York, 2022. http://dx.doi.org/10.1093/oso/9780197655832.003.0006.

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Abstract As part of a more encompassing constraint of public reason, a constraint of constitutional fidelity applies “more strictly,” John Rawls writes in Political Liberalism, to supreme court judges acting in their adjudicative capacities than to democratic citizens acting politically as litigants, voters, organizers, and otherwise as agitators for political causes. On a first look, this chapter finds it to be unclear how this proposition can fit with Rawls’s proposal (“the liberal principle of legitimacy”) for reliance on a country’s constitution as a public procedural pact for the justification, among citizens in a democracy, of the force of controversial laws and political policies. An answer lies in the thought that a justificatory load-bearing constitution undergoes temporal stress. While citizen-adherents to a constitutional procedural pact must be able to reconfirm at all times its elements of prior fixation as established framework law, a pact of justification also must undergo reconfiguration of those elements in the public understanding as, over the course of historical time, a country’s conditions change and society learns from experience and from democratic political interaction. A constitution meeting these requirements would show aspects of what many theorists might call a common-law character, within the wider domain of positive legality. It would figure for its country both and simultaneously as fixture and as project. While judges in law courts are to represent the element of fixture, it is the political agitations of a democratic citizenry that will keep the project going.

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Hesse, David. "Home is where the Heart is: Affinity Scots in the Scottish Diaspora". En Global Migrations. Edinburgh University Press, 2016. http://dx.doi.org/10.3366/edinburgh/9781474410045.003.0013.

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The kilted men are a yearly fixture. Visit the Swiss city of Basel during the three days of carnival – and you will come across the Scots. They will be marching in parades, playing bagpipes, wearing tartan – and often wearing other things as well: demonic masks of papier mâché, oversized heads and noses, garish fantasy costumes. They combine the Scottish pipe and drum band tradition with the local carnival aesthetic. These are the men (and only men) of Schotte Clique; their name quite simply means Scottish krewe or band. Founded in 1947, they have performed every year since without interruption. Many consider Schotte Clique one of the finest and most prestigious carnival krewes in the city; sixty-six active and several hundred passive members wear their Scottish gear with pride and meet regularly throughout the year. Carnival in Basel lasts for only three days, but the cliques provide a social identity that delivers all year round. Schotte Clique change their masks and costumes with every season – the production of such material at home or at the clubhouse is one key aspect of Basel’s carnival culture. But every year there will be some Scottish element involved. In February 2014, Schotte Clique marched as a group of kilted Santas, and the year before they were medieval knights, their skirt-like leg wear resembling a Scottish fashion.

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"Evidence of corrosion in home piping system began to appear in fixture stains and metallic taste. In 1985, the Federal Government did surveys of heavy metals in water supplies, focusing on lead in drinking water and its effect on children. The prevalence of this metal resulted in the banning of lead from solder used in plumbing. In 1988, and in 1989, regulations reduced the safe limit of lead in water from 50^gm/L to 5 μgm/L, with an action level at 15pgm/L in a first draw sample. At the same time the E.P.A. provided guidance documents to schools and day care centers to help reduce children's lead exposure in water supplies. Grants were made available to states to be used for spreading the knowledge about this danger. However, the Federal regulations applied only to public water supplies, which were defined as systems serving 25 or more people. But private wells serving family homes, many containing children, were not included. Children could be assured of regulated water supplies in school, but not at home. Aware that lead was a problem in paint chips, Connecticut required that pediatricians test for traces of lead in children at age two. The Federal act recognized that the primary source of lead in water supplies came through home plumbing systems stemming from the corrosion by the water. This was remedied by requiring public water supplies to prevent corrosion, usually by adding alkalinity to the water. Here again, private wells not included in the educational phase of the program were also not included in the remedies. While these activities with water supplies were occurring, a phenomenon of a different sort was originating in states hundreds of miles away from Southeastern Connecticut. Throughout the Midwest and into West Virginia and Kentucky, electric power generators were erecting tall stacks to disperse sulfur dioxide gasses high into the atmosphere. The gas came mostly from the burning of high sulfur coal mined nearby. The Federal air pollution standards for ambient air were being met in the Midwest by the use of these tall stacks. In the eastern states, restrictions on sulfur content of fuels, mostly petroleum based, were used to meet the ambient air standards. By the early 1980's Connecticut eased its restrictions on sulfur content in these fuels from 0.5% to 1% by weight . Still, during the next five years the sulfur dioxide level actually decreased. However, in 1986, other data collected by the State showed that 32% of the rain storms had an acidic pH of 4.0 or below [ 1 ]. The lowest pH ’ s recorded that year were 3.6. The State also reported that from 1985 to 1996 there had been a further decrease in ambient sulfur dioxide levels [ 2 ]." En Hazardous and Industrial Waste Proceedings, 30th Mid-Atlantic Conference, 860. CRC Press, 2014. http://dx.doi.org/10.1201/9781498709453-139.

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Actas de conferencias sobre el tema "Active fixtures"

Joshi, Pranit Satish y Khurram Moghal. "Impact of Active Cooling On High Power Density Fixtures". En The 8th World Congress on Mechanical, Chemical, and Material Engineering. Avestia Publishing, 2022. http://dx.doi.org/10.11159/htff22.142.

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Papastathis, Thomas N., Otto Jan Bakker, Svetan M. Ratchev y Atanas A. Popov. "Experimental Validation of Active Fixture Design Methodology". En ASME 2014 International Manufacturing Science and Engineering Conference collocated with the JSME 2014 International Conference on Materials and Processing and the 42nd North American Manufacturing Research Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/msec2014-4166.

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A design methodology for active and fully-active fixtures has been established previously. In this work the results of a part of the validation for the design are presented, namely the differences between two different layouts and the difference between application of an passive and active clamp. The test-bed consist of a reconfigurable fixturing system with an active clamp holding a thin-walled plate. For three cases passive and actively controlled clamping forces were exerted during a series of milling operations. These are (1) passive clamping at a suboptimal and (2) at the optimal position and (3) clamping with an actively controlled clamping force at the optimal clamping location. The previously proposed design procedure has been qualitatively validated since its predictions regarding optimal layout and adaptive clamping forces hold true, when comparing the surface finishes, which improve from case to case.

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Mehdi, Ghulam, Hu Anyong, Zheng Cheng, J. Miao y Abdul Mueed. "Characterization of Millimeter-Wave Active and Passive Components Embedded in Test Fixtures". En 2013 11th International Conference on Frontiers of Information Technology (FIT). IEEE, 2013. http://dx.doi.org/10.1109/fit.2013.32.

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Fehlberg, Mark A., Raymond J. King, Andrew J. Doxon y William R. Provancher. "Evaluation of Active Handrest performance using labyrinths with adaptive admittance control and virtual fixtures". En 2012 IEEE Haptics Symposium (HAPTICS). IEEE, 2012. http://dx.doi.org/10.1109/haptic.2012.6183802.

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Naing Aye, Yan. "An Active Handheld Instrument Aided with Virtual Fixtures for Real-Time Micromanipulation Using Fusion of Vision and Inertial Sensing". En Proceedings of The 3rd IFToMM International Symposium on Robotics and Mechatronics, chair Su Zhao, Zenan Wang y Wei Tech Ang. Singapore: Research Publishing Services, 2013. http://dx.doi.org/10.3850/978-981-07-7744-9_088.

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Li, Xiaoping y Andrew Y. C. Nee. "A Simulation System for Feasibility Study of Single Set-Up Fixtures in Milling and Drilling". En ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-1155.

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Abstract Single set-up fixtures in milling and drilling processes are usually desired because of its high efficiency. One of the main difficulties in designing such fixtures is to estimate the deformation corresponding to the processes under consideration. In this aspect, theoretical calculation of the workpiece deformation has hardly been achieved due to the complication caused by interactions between the cutting forces and clamping forces on the workpiece. Traditionally the workpiece deformation under a fixture is estimated approximately based on the designer’s experience. In this paper, a system for simulation of workpiece deformation in end milling and drilling processes is developed. In the system, from a given plan of fixture setup and machining conditions, the cutting forces and clamping forces acting on the workpiece are firstly predicted using theoretical and empirical models, then the corresponding deformations throughout the workpiece are calculated from the forces and workpiece material properties using the finite element method. As a case study, the system is used to investigate workpiece deformation in end milling a slot and drilling a hole on a workpiece with different configurations of single set-up fixture. It is shown that by using the simulation system the effect of different configurations of single set-up fixture on the deflections of the workpiece can be accurately estimated. In this way the feasibility of a single set-up fixture design can be studied and the design can be optimized on a scientific basis.

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O’Malley, Marcia K. "Shared Control for Upper Extremity Rehabilitation in Virtual Environments". En ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81782.

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Interest in the rehabilitation applications for robots has been increasing. For example, various devices have been developed to aid in reaching movements of stroke, traumatic brain injury (TBI), and spinal cord injury (SCI) patients. Typically these devices provided guided reaching movements for elbow and shoulder. The robotic aspect allows for repeatability, along with additional data for post-session analysis. To date, robotic rehabilitation systems with haptic feedback have not fully exploited the capabilities of a haptic display device. The simulators primarily focus on obeying the physical laws that govern such systems in order to re-create realistic environments for rehabilitative tasks, or the robotic devices are employed only for their ability to carry the impaired limb through various trajectories. This paper will present a novel active assistance paradigm for interactions in virtual environments displayed via haptic interfaces. The author’s recent research efforts have focused on the design of perceptual overlays in virtual environments that are active rather than passive. Passive virtual fixtures have been the primary perceptual overlay in haptics, and have been used extensively as “virtual rulers” in teleoperation environments to improve operator performance of pick-and-place tasks. Active assistance in the form of shared control between the haptic device and the human operator has the potential to elicit even better performance in virtual and remote environment interactions, and also has implications for improving training effectiveness. The intended applications include stroke rehabilitation and training for pilots, manufacturing, and surgery. A description of perceptual overlays and details of the shared control paradigm are presented, along with results from some preliminary experiments on shared control haptic assistance for training in virtual environments.

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Lian, Jun, Zhongqin Lin, Fusheng Yao y Xinmin Lai. "Analysis of Nonlinear Variation Accumulation in Auto-Body Assembly Process". En ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32339.

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In the assembly process of auto-body, variations in the geometrical dimensions of sheet metal parts and fixtures are inevitable. These variations accumulate through the multi-station assembly process to form the dimensional variations of the final products. Compared with the assembly of rigid parts, the assembly process of the elastic parts is more complex because the variation accumulation patterns rely much on the variations of fixture, jointing methods and mechanical deformation. This paper aims at analyzing the variation transformation mechanism and accumulation characteristics for the assembly of sheet metal parts based on the analysis of dimensional coordination relations among parts and fixtures. Finite element method (FEM) and Monte-Carlo Simulation (MCS) were used to analyze the effect of jointing contact on variation transformation, while a state equation was developed to describe the variation accumulation mechanism. The result of the analysis indicates that the main characteristics of elastic assembly jointing are the overlap jointing methods and elastic contacts action. The fact that the variation transform coefficients (VTC) are variable makes the assembly variation distribution Non-Gaussian even if the dimension variation of parts is Gaussian distribution. The analysis conclusions have potential value for more reasonable tolerance synthesis of elastic parts assembly.

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Rong, Yiming (Kevin), Sheng-hua Wu y T. Philip Chu. "Automated Verification of Clamping Stability in Computer-Aided Fixture Design". En ASME 1994 International Computers in Engineering Conference and Exhibition and the ASME 1994 8th Annual Database Symposium collocated with the ASME 1994 Design Technical Conferences. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/cie1994-0427.

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Abstract This paper presents a method for automated verification of clamping stability in computer-aided modular fixture designs. When a modular fixture design is conducted by using a CAD system, equilibrium between clamping forces and locating responses needs to be evaluated for a reliable locating. If the positions and directions of locating and clamping components are not appropriately placed, the clamping action may not secure the locating but destroy it. In this paper, two technical problems related to clamping stability verification are studied: automated extraction of positions/directions of clamping forces and locating responses, and evaluation of clamping equilibrium of the fixture design. The automated extraction of the locating/clamping positions/directions is implemented by adding special attributes into a fixture component CAD database based on an analysis of locating and clamping methods using modular fixture components. To verify the clamping stability of a fixture design, the clamping forces are assumed as active and known input forces, and the locating responses are passive and variables to be solved. In the solution, all locating responses should be non-negative for a stable clamping, and the friction should be in a feasible range for a stable clamping.

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Kurzawski, Andrew y Ofodike A. Ezekoye. "Foam Insulation Behavior in Void Space Under Fire Conditions". En ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-38849.

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A fire contained within a room can spread into void spaces in the walls and ceiling through penetrations in the material that lines the compartment. Few studies have looked at how a room and contents fire transitions to a structural fire. One of the active areas of fire research is the coupling of the fire to the structure. Lightweight wood frame construction represents the majority of residential construction in the U.S. The construction details and choice of materials will affect the overall fire resistance of the structure. Because of the relative lack of knowledge on the fire penetration into wall spaces, this research examined how fire might penetrate into the void spaces of wood framed structures. In the U.S.A., a critical barrier to the penetration of hot gas products into void spaces is provided by the gypsum-board skin of the compartment. For most compartments, there are many penetrations within the compartment’s gypsum-board skin. Common potential access points include security system wiring (e.q. smoke detectors and cameras), ventilation fixtures, light switches, and electrical outlets among others. A hole in the gypsum may create opportunities for void space ignition. One of the purposes of this work is to develop a small scale testing system to characterize fire driven flow and heat transfer into a void space. With such an apparatus, one can rapidly identify materials that are prone to igniting for a given leakage geometry and fire size. Common materials found in void spaces include wooden structural members, plywood/oriented strand board, a variety of insulation types, and vapor barriers. This study discusses the characteristics of the small scale experimental system and preliminary tests on a range of void space construction materials.

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Willis, Craig, Will Hughes y Sergiusz Bober. ECMI Minorities Blog. National and Linguistic Minorities in the Context of Professional Football across Europe: Five Examples from Non-kin State Situations. European Centre for Minority Issues, diciembre de 2022. http://dx.doi.org/10.53779/bvkl7633.

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Football clubs are often analysed by scholars as ‘imagined communities’, for no fan of any team will ever meet, or even be aware of most of their fellow supporters on an individual level. They are also simultaneously one of the most tribal phenomena of the twenty-first century, comparable to religion in terms of the complexity of rituals, their rhythm and overall organizational intricacies, yet equally inseparable from economics and politics. Whilst, superficially, the events of sporting fixtures carry little political significance, for many of Europe’s national and linguistic minorities football fandom takes on an extra dimension of identity – on an individual and collective scale, acting as a defining differentiation from the majority society. This blogpost analyses five clubs from non-kin state settings, with the intention to assess how different aspects of minority identities affect their fan bases, communication policies and other practices.

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