Academic literature on the topic 'Linear springs'

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Journal articles on the topic "Linear springs"

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Cadet, Guillaume, Manuel Paredes, and Hervé Orcière. "Improved analytical model for cylindrical compression springs not ground considering end behavior of end coils." Mechanics & Industry 22 (2021): 50. http://dx.doi.org/10.1051/meca/2021048.

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In a context of increased competition, companies are looking to optimize all the components of their systems. They use compression springs with constant pitch for their linear force/length relationship. However, it appears that the classic formula determining the global load-length of the spring is not always accurate enough. It does not consider the effects of the spring's ends, which can induce non-linear behaviour at the beginning of compression and thus propagate an error over the full load-length estimated. The paper investigates the entire behaviour of a cylindrical compression spring, not ground, using analytical, simulation and experimental approaches in order to help engineers design compression springs with greater accuracy. It is built with an analytical finite element method, considering all the geometry and force components of the spring. As a result, the global load-length of compression springs can be calculated with more accuracy. Moreover, it is now possible to determine the effective tri-linear load-length relation of compression springs not ground and thus to enlarge the operating range commonly defined by standards. This study is the first that enables the behaviour to be calculated quickly, by saving time on dimensioning optimisation and on the manufacturing process of compression springs not ground.
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Parise, John J., Larry L. Howell, and Spencer P. Magleby. "Ortho-planar linear-motion springs." Mechanism and Machine Theory 36, no. 11-12 (November 2001): 1281–99. http://dx.doi.org/10.1016/s0094-114x(01)00051-9.

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Kornhauser, A. A. "Dynamic Modeling of Gas Springs." Journal of Dynamic Systems, Measurement, and Control 116, no. 3 (September 1, 1994): 414–18. http://dx.doi.org/10.1115/1.2899236.

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Linear dynamic modeling of gas springs is important for basic design of free piston Stirling engines. The conventional gas spring model, a dashpot in parallel with an ideal spring, gives poor prediction of gas spring performance. The anelastic model presented here consists of two parallel springs, one of which is in series with a dashpot. With proper selection of spring and damping constants, it gives improved prediction of gas spring dynamics.
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Chuanchao, Yan, and Zhao Wen. "The use of pneumatic cylinders with return springs when creating mechanical drives with recuperative energy." MATEC Web of Conferences 287 (2019): 01028. http://dx.doi.org/10.1051/matecconf/201928701028.

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The use of pneumatic cylinders with return springs in mechanical drives with reusable energy for reusable and continuum movements, fixing the output link in the extreme positions are considered. A defined range of work operations can be used by these cylinders. The use of pneumatic actuators with return springs in mechanical drives based on linear spring batteries with two springs is proposed. Algorithms for compensating dissipative losses in mechanical spring drives are considered. The maximum mass values that can be moved by such mechanical drives for each size of the pneumatic cylinder are determined. It is proposed to use pneumatic cylinders with return springs in mechanical drives with energy recovery based on nonlinear spring batteries. A mechanical spring drive for unwinding rolls of packaging materials with discrete modes. In tasks of reciprocating movement of objects with a controlled stand in extreme positions, the reduction of energy costs is achieved when using mechanical spring drives with energy recovery. Energy costs can be reduced several times. Traditionally, a spring-loaded drive contains a linear or non-linear spring-loaded battery, a control system, controlled clips and a motor to compensate for dissipative losses. The use of electric motors to compensate for dissipative losses is also limited by low speed, as compensation for dissipative losses occurs throughout the displacement and with high speed increases engine power and requires transmission with a large gear ratio.
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Badalamenti, J. M., and G. R. Doyle. "Radial-Interradial Spring Tire Models." Journal of Vibration and Acoustics 110, no. 1 (January 1, 1988): 70–75. http://dx.doi.org/10.1115/1.3269483.

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Two radial-interradial spring tire models are developed to predict vertical and drag forces produced by a tire as it rolls over an obstacle. Interradial springs are used to interconnect radial linear or quadratic springs to make each tire element’s deflection dependent upon its adjacent element’s deflections. Forces predicted by these two models are compared with a previously developed quadratic radial spring tire model and test data. The newly developed quadratic radial-linear interradial spring tire model predicts vertical and drag forces that are in close agreement with the test data.
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Ryu, Takahiro, S. Rosbi, K. Matsuzaki, T. Nakae, A. Sueoka, Y. Takikawa, and Y. Ooi. "Effect of Stiffness Ratio of Piecewise-Linear Spring on the Occurrence of Subharmonic Nonlinear Vibration in Automatic Transmission Powertrain." Applied Mechanics and Materials 786 (August 2015): 156–60. http://dx.doi.org/10.4028/www.scientific.net/amm.786.156.

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In the torque converter, a damper with a piecewise-linear spring is used to reduce the forced vibration, and the subharmonic vibration occurs when the spring restoring torque characteristics approach the switching point. This research analyzed the effect of stiffness ratio between the neighboring piecewise-linear springs on the occurrence of the subharmonic nonlinear vibration in automatic transmission powertrain. The powertrain is modeled with multi degree-of-freedom nonlinear system as an actual vehicle. The result shows higher value of the stiffness ratio between the neighboring springs creates larger value of the subharmonic vibration.
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Pedersen, N. L., and P. Pedersen. "Stiffness and design for strength of trapezoidal Belleville springs." Journal of Strain Analysis for Engineering Design 46, no. 8 (September 13, 2011): 825–36. http://dx.doi.org/10.1177/0309324711414337.

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Belleville springs or coned disc springs are commonly used in machine design. The geometric dimensions of the spring and the determination of non-linear force–displacement curve are regulated by different standards. However, the theory behind Belleville spring design standards is founded on a study published in 1936. Furthermore, the common spring design with cross-sections of uniform thickness poses problems in terms of non-uniformity of stress distribution. In view of this, non-linear three-dimensional finite element analyses of spring designs including uniform or variable thickness are carried out in this paper. Finite element results are compared with analytical predictions and critically analysed in terms of the effect of Poisson ratio, overall stiffness, and stress distribution in the spring. This is done in order to verify the range of validity of design standards. Finite element analysis emerges as a powerful and computationally cheap approach to assess the structural behaviour of Belleville springs regardless of their geometry and level of non-linearity.
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Baier-Saip, Jürgen A., Pablo A. Baier, Klaus Schilling, and Jauvane C. Oliveira. "Approximate Artery Elasticity Using Linear Springs." Journal of Medical and Biological Engineering 37, no. 6 (June 17, 2017): 899–911. http://dx.doi.org/10.1007/s40846-017-0254-0.

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Rathi, Vinay Kumar, Shobha Ram, Rohitashw Kumar, Avinash Agarwal, and R. K. Nema. "Hydrological classification and performance of Himalayan springs in climate change scenario – a case study." Water Supply 20, no. 2 (December 27, 2019): 594–608. http://dx.doi.org/10.2166/ws.2019.191.

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Abstract The present study was conducted to evaluate 33 springs' hydrology (discharge and yield estimation) of Chandrabhaga and Danda watersheds of Uttarakhand, India. The springs were classified using Meinzer method and evaluated the relative performance for rejuvenation strategy. It was found that most of springs fall in sixth and seventh class order with flow rate 6.5 to 65.5 and 0.8 to 6.5 m3·day−1, respectively. The relative performance of springs were analyzed based on four methods: (i) spring flow variability, (ii) normalized spring flow (short and long duration), (iii) rainfall spring flow lag and (iv) spring flow gradient. The relative results of springs were analyzed on a scale of 0–5. The Chandrabhaga springs 01, 03, 4B, 05, 06 and 13 were found to be relatively good on a scale value of 4 out of 5 as compared to springs 4A, 07, and 10A with a scale value of 1. For the Danda watershed, the relative performance of springs 4A and 28 found on scale value of 5 and springs 4B, 11 and 20 with a scale value of 4 are relatively good compared to springs 02, 06, 07, 15 and 17. The cumulative flow of spring showed a linear response with cumulative rainfall for the period of June to September (monsoon period). The spring-shed was delineated and evaluated for optimization for the maximum efficiency, spring flow, ratio of area and relief versus maximum spring flow yield. The results revealed that the quantification of water fluxes for water balances, storage of groundwater and development of mathematical models can be used for sustainable water resources development and to revive the mountain springs which helped the adverse impacts of climate change.
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Chaudhury, Arkadeep Narayan, and Debasis Datta. "Analysis of prismatic springs of non-circular coil shape and non-prismatic springs of circular coil shape by analytical and finite element methods." Journal of Computational Design and Engineering 4, no. 3 (February 8, 2017): 178–91. http://dx.doi.org/10.1016/j.jcde.2017.02.001.

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Abstract This paper presents a methodology for designing prismatic springs of non-circular coil shape and non-prismatic springs of circular coil shape using analytical and numerical methods. To start with, simple analytical formulations for obtaining the axial deformation of the springs under axial load have been demonstrated. Next, the processes of obtaining CAD models of the springs and their subsequent finite element analysis (FEA) in commercial softwares have been outlined. In the third part, the different springs have been compared with a common cylindrical spring and their merits compared to a common spring have been demonstrated. Next, a fairly accurate analytical formulation (with maximum error of ∼7–8%) for obtaining the value and location of maximum shear stress for all the springs has been demonstrated. Next, two aspects of non-prismatic springs under dynamic loads, viz. damping introduced in a vibrating system and contribution of the spring to the equivalent mass in a one dimensional vibrating spring mass system due to shape of the spring have been discussed. The last part involves an analytical formulation for the linear elastic buckling of two springs with circular coil shapes. For the majority of the work, emphasis has been on obtaining and using closed form analytical expressions for different quantities while numerical techniques such as FEA have been used for validation of the same. Highlights Analytical formulations of axial deflection different springs under axial load. CAD modeling and FEA of prismatic and non prismatic springs of different coil shapes. Comparison of stress and deflection in mass-equivalent springs of different geometry. Approx. analytical formulation for the location and value of max. stress in springs. Effects of spring shape on damping, vibrational properties in 1D systems and buckling.
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Dissertations / Theses on the topic "Linear springs"

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Schjølberg, Martin. "Planned Test of the Prototype 2B Linear Machine with Gas-Springs for Energy Harvesting from Waves." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14766.

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This paper describes a proposed test plan for harvesting energy from waves with a linear machine that uses gas-springs. The linear machine “Prototype 2B” has been put into production and will be finished. The machine has been constructed to withstand 300 bars of gas pressure and the maximum speed of the rotor is set to 10 m/s due to the sealing. The model made in [5] uses the fundamental equations and describes the system behavior of a linear machine with gas springs. The model has been slightly improved and the input specifications for the “Prototype 2B” have been used. The simulations shows that one needs to feed electric energy in some parts of the cycle, but the whole cycle will yield a positive net contribution of electrical energy. The model is not optimized, and hence should be improved due to the time consuming simulations. Steel profiles have been proposed to use for the frame of the test-bench. The first draft of the drawing has been sent to NTNU and the workers have started to build the frame. To ensure the vibration energy to spread itself into the surroundings, isolators need to be selected and adapted. The natural frequency of the test bench with four chosen isolators was calculated to 18,17Hz. The chosen isolators are therefore most likely good enough since the lowest operating frequency of the machine was simulated to 55 Hz.Transferring the energy from the high-force-low-speed source (the wave) to the resonator has been discussed and some suggestions have been proposed. The energy transfer is done by raising pressure in a freestanding actuator with a hose connected to the gas spring. Hence, increasing the actuator pressure will increase the gas spring pressure and the force acting on the rotor will be significantly higher. A procedure to select the correct components are discussed and a Matlab script for analyzing the choice has been made. The high-force-low-speed source has been discussed. Two solutions where a hydraulic system is used have been further investigated, and some calculations and analysis have been performed. Simulations show that one need to apply a maximum force of 24115N at one actuator with a 32mm effective piston area. The regulation of the high-force-low-speed source could be crucial to obtain a good test result since the regulation of the wave must adapt itself to the resonating force of the rotor. The regulation must therefore be investigated further as it can have tremendous impact on the possibility of extracting energy from the machine.The electrical source and regulation control have been discussed. Timing of the electrical energy supplied is crucial and three operational simulations have been performed to investigate when the positive net contribution is at it`s highest. In order to extract the maximum possible net energy from the machine, the right electrical control is very important to implement. Two of the control systems have been proposed, where perhaps the simple proportional controller should be chosen to prove the concept. Later on a more sophisticated electrical controller should be applied since the efficiency of the wave energy converter could increase significantly.The non-linear compression event in the gas-springs is not proportional to the electrical extracted energy. Simulations show that when the pressure increases in the springs one could extract more energy, but the non-linear event could not be recognized. Simulations show that the efficiency of the system varies significantly with the controlling of the machine. If a simple proportional controller is adapted, the theoretical efficiency becomes 2,87% and with a more sophisticated controller one could get 10,02%. This means that there must be done more research on the electrical operating control system if energy harvesting could be profitable.
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Kilic, Mehmet. "Design And Development Of A Mechanically Adjustable Linear Torsion Spring Using Cams." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610960/index.pdf.

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Linear springs with variable stiffnesses find some key roles in robotic applications. They are implemented into robotic devices for two main reasons, to increase energy efficiency of walking-running robots and prosthesis, and to get safe human-robot interaction at industrial robots. Being inspired from the human actuation system, a mathematical method to get mechanically adjustable linear springs is noted in the literature
antagonistically working two quadratic springs method. But the proposed solution requires two non-linear springs with quadratic spring characteristics and they are not readily available. Several solutions have been noted in the literature for the acquisition of such non-linear springs. At this thesis work, the solution is realized with a string wrapping around cam mechanism. Two different prototypes were designed and constructed and the second one was physically tested to validate the linear spring behavior. The results displayed good linear spring characteristics with different levels of adjustable spring stiffness. Beside the antagonistically working two quadratic springs method, three novel methods to get mechanically adjustable linear springs are introduced at this thesis. They are based on using hanging weights, an exponential characteristic spring and a linear translation spring respectively. The real prototypes were not manufactured but sample designs using string wrapping around cam mechanisms are made.
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Oliveira, Fernando Emerenciano Nunes de. "Controles semiativos e observador de estados não linear aplicados em suspensão veicular com amortecedor magneto-reológico." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2904.

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Comprovadamente, o sistema de suspensão veicular passivo é uma proposta confiável e econômica de solução tanto para redução dos níveis de vibração do chassi e da roda, quanto para a redução dos níveis de aceleração do chassi. Embora este sistema seja amplamente empregado nos veículos, ele apresenta a desvantagem que seus parâmetros não podem ser modificados de acordo com as variações geradas pela pista. Com isso surge o emprego da utilização do sistema de suspensão ativa, que possibilita a variação dos parâmetros da suspensão a tempo real, no entanto, o emprego deste tipo de suspensão requer um elevado nível de energia para o funcionamento correto de seus atuadores, acarretando na inviabilidade de algumas aplicações. Para solucionar as desvantagens encontradas para o sistema de suspensão passivo e ativo, surge o sistema de suspensão semiativo, que reúne as vantagens do sistema ativo, porém com um menor consumo de energia, gerando consequentemente uma opção de controle confiável e econômica de solução para os problemas de dirigibilidade e conforto veicular. O presente trabalho pretende realizar duas avaliações, sendo a primeira, a avaliação e comparação de um sistema de suspensão passivo com o desempenho de quatro controladores semiativos (on/off, skyhook, groundhook e híbrido) e a segunda é testar os mesmos controladores, porém considerando a dinâmica de um amortecedor magnético-reológico através do modelo de LuGre. Estes controladores serão aplicados a um modelo não linear de um quarto de carro com dois graus de liberdade, sendo as suas variáveis estimadas, através de um observador de estados não linear. A análise para a comparação dos sistemas será realizada através de simulações numéricas utilizando o software MatLab®. As simulações dos distúrbios gerados pela pista serão realizadas através de uma função degrau e uma função pulso com o objetivo de avaliar o desempenho de cada controlador. Após a implementação dos algoritmos de controle, foi possível verificar que o sistema de suspensão semiativo, frente às excitações propostas, apresentou um desempenho superior em relação ao conforto. Contudo, não tão significativas quanto ao do conforto, o sistema controlável também, comparativamente ao sistema passivo, apresentou melhoras no requisito dirigibilidade.
Proven, the passive vehicle suspension system is a reliable and cost-effective solution solution for both chassis and wheel vibration levels reduction and chassis acceleration levels reduction. Although this system is widely used in vehicles, it has the disadvantage that its parameters can not be modified according to the variations generated by the track. This results in the use of the active suspension system, which allows the variation of the parameters of the suspension in real time, however, the use of this type of suspension requires a high level of energy for the correct operation of its actuators, resulting in the unfeasibility of some applications. To solve the disadvantages found for the passive and active suspension system, the semiactive suspension system arises, which combines the advantages of the active system, but with a lower energy consumption, consequently generating a reliable and economical solution control option to the problems of maneuverability and vehicular comfort. The present work intends to perform two evaluations, the first being the evaluation and comparison of a passive suspension system with the performance of four semi-active controllers (on/off, skyhook, groundhook and hybrid) and the second is to test the same controllers, but considering the dynamics of a magneticrheological damper through the LuGre model. These controllers will be applied to a nonlinear model of a quarter-car with two degrees of freedom, with its variables being estimated through a nonlinear state observer. The analysis for the comparison of the systems will be performed through numerical simulations using MatLab® software. The simulations of the disturbances generated by the track will be performed through a step function and a pulse function in order to evaluate the performance of each controller. After the implementation of the control algorithms, it was possible to verify that the system of semi-active suspension against the proposed excitations presented a superior performance in relation to comfort. However, not as significant as comfort, the controllable system alo compared to the passive system, presented improvements in the steerability requirement.
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Ganzarolli, Francisco. "Influência das frequências de ride no conforto e dirigibilidade veiculares na faixa linear de uso do veículo." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-05092012-073800/.

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O tema do conforto na automobilística é bastante extenso e possuidor de muitas interpretações. A ideia central deste trabalho é definir e direcionar alguns métricos para que, durante as fases de conceituação e desenvolvimento de um veículo, seja possível ter um direcional de definição de componentes e atributos veiculares de modo a facilitar o direcionamento dos atributos no programa veicular, e assim atingir suas necessidades. Como exemplo empregado, é empregado um veículo de plataforma tipo B em desenvolvimento por uma montadora, o qual teve as molas de suspensão definidas e rigidezes laterais de eixos com base em material técnico interno equivalente aos estudos apresentados neste trabalho. É adotada uma abordagem inicialmente empírica conforme os primeiros estudos de suspensões independentes realizados neste continente, depois o trabalho é complementado com exigências de normas especificas para vibrações (ISO2361, ISO5008, BS6055) de modo a caracterizar energia vibracional e a interpretação pelo ser humano. Porém como hoje em dia as suspensões automotivas são muito mais complexas, existem componentes específicos para as várias condições de solicitação, deste modo a análise é limitada a situações de ride (conforto) primário e handling (dirigibilidade) em situações de sublimite na faixa linear (cerca de 0,5 g). Como conclusão dos estudos, é possível ter em um veículo atributos de estabilidade sem necessariamente prejudicar o conforto, pois sendo definidos corretamente os componentes elásticos da dinâmica vertical para situações estacionárias e de ride primário, é definido seu equilíbrio estacionário e assim não é necessário comprometimento dos atributos de outros componentes para compensar alguma deficiência existente.
The range of assumptions for ride comfort is considered very wide in the automotive world and they can assume lots of possible interpretations. The central idea in this work is define and manage some metrics that, during the concept and development phases of a vehicular program, be possible to follow a better direction for the attributes development and so reach the program targets. As the example in this work, a B platform typical vehicle is used and it is under development in a carmaker, its suspension springs and axle roll stiffness were setup with technical information similar to the ones presented in this work. The initial approach is empiric as occurred with the first independent suspension system studies in this continent and in the sequence, the work is complemented with standards for vibrational issues (ISO2361, ISO5008, BS6055), after this, finally how the vibrational energy is defined and perceived by human beings. The automotive suspensions of current days are very complex and there are lots of specific components to do a specific work, so the analysis are limited to primary ride and sub limit handling (up to 0,5 g). As conclusion, its possible setup a car that is comfortable and stable in the same time, since the elastic components for the vertical dynamics and steady state conditions are correctly set, so its correct balance is reached and no other components attributes are compromised to compensate any deficiency.
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Švrček, Jakub. "Třísítný vibrační třídič." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-416620.

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This diploma thesis deals with the design of an inclined three-sided vibrating screen, which is designed for sorting bulk aggregates. The aim of the diploma thesis is primarily to make a construction design with a specific comparison of various design solutions, considering the calculated operating parameters. In the construction design, is used not only the experience of the manufacturer of this type of machine, but also recommendations based on the manu-facturers of screens component. The design also includes a comparison of two types of flex-ible mounting, which is one of the basic structural units of the entire vibrating screen. The thesis is conceived from the basics, with emphasis on the simplicity and functionality of the device.
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Laing, Kara Louise. "Non-linear deformation of a helical spring." Thesis, University of East Anglia, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323220.

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Hill, Bradford K. Greene Michael E. "A linear CMOS tunable active resistor." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SPRING/Electrical_and_Computer_Engineering/Thesis/Hill_Bradford_35.pdf.

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Rubalcaba, Roberto Ramon Johnson Peter D. "Fractional domination, fractional packings, and fractional isomorphisms of graphs." Auburn, Ala., 2005. http://repo.lib.auburn.edu/EtdRoot/2005/SPRING/Mathematics/Dissertation/RUBALCABA_ROBERT_56.pdf.

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Hall, Anthony R. "The Pseudo-Rigid-Body Model for Fast, Accurate, Non-Linear Elasticity." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3869.

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We introduce to computer graphics the Pseudo-Rigid-Body Mechanism (PRBM) and the chain algorithm from mechanical engineering, with a unified tutorial from disparate source materials. The PRBM has been used successfully to simplify the simulation of non-linearly elastic beams, using deflections of an analogous spring and rigid-body linkage. It offers computational efficiency as well as an automatic parameterization in terms of physically measurable, intuitive inputs which fit naturally into existing animation work flows for character articulation. The chain algorithm is a technique for simulating the deflection of complicated elastic bodies in terms of straight elastic elements, which has recently been extended to incorporate PRBM beam-elements in three dimensions. We present a new, mathematically equivalent optimization of the 3D PRBM chain algorithm, from its former asymptotic complexity of O(n^2) in the number of elements n, to O(n). We also extend an existing PRBM for combined moment-force loads to 3D, where the existing 3D PRBM chain algorithm was limited to 3D PRBM elements for a moment-only load. This optimization and extension are validated by duplicating prior experimental results, but substituting the new optimization and combined-load elements. Finally, a loose road-map is provided with several key considerations for future extension of the techniques to dynamic simulations.
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Evans, Megan Elizabeth. "Determining a Relationship Between Posterior Chain Flexibility and Linear Sprint Speed." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/47430.

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One very common axiom amongst Strength and Conditioning Professionals and Athletic Performance Coaches is that the least flexible athletes usually produce the fastest 40-yard dash times. Flexibility, in this case specifically refers to posterior chain flexibility (PCF). This is usually measured by athletes ability to perform a sit-and-reach test. This train of thought has been widely accepted within the human performance professions, even though it is void of any scientific investigation or measured validity. The purpose of this study is to determine if there is a relationship between posterior chain flexibility using the sit-and-reach test and speed in the 40-yard dash. All test subjects were male between the ages of 18-22, and members of a Division I university football team. All 95 test subjects had participated in at least one semester of a strength and conditioning program designed by Certified Strength and Conditioning Specialists. Similar of the study done by Johnson (2001), each athlete was placed in a group based on position, line of scrimmage groups (LOS), Skill group (receivers, cornerbacks, rover linebackers, whip linebackers, and safeties), Combo group (inside linebackers, tight ends, quarterbacks, tailbacks, fullbacks, and defensive ends), Specialist group (place- kickers, kick-off specialists, holders, and punters). Each test subject was tested in the 40-yard dash, the sit-and-reach flexibility test, as well as other tests for strength and power such as the bench press, front squat, push jerk, power clean, vertical jump, and agility tests. Body weight and height was also measured. This study used a simple linear regression on the data where the Sit-and-Reach test results were the dependent variable and the subjects timed results in a 40 yard dash was the independent variable. There appears to be no significant relationship between a low flexibility score and the sprint speed of an athlete for the entire group population. The results also show that there is no significant relationship between flexibility of the posterior chain and linear speed as measured in the 40-yard dash when looking at football players that fall under the Combo, Skill, or LOS position groups. There was however a significant relationship for the specialist group. The theory that the least flexible athletes usually produce the fastest 40-yard dash times is not true for those specific groups.
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Books on the topic "Linear springs"

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H, Gold Steven, Nusinovich G. S, University of Maryland (College Park, Md.), Naval Research Laboratory (U.S.), and United States. Dept. of Energy., eds. High energy density and high power RF: 6th Workshop on High Energy Density and High Power RF, Berkeley Springs, West Virginia, 22-26 June 2003. Melville, N.Y: American Institute of Physics, 2003.

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Symposium E on Synthetic Metals for Non-linear Optics and Electronics (1992 Strasbourg, France). Synthetic metals for non-linear optics and electronics: Proceedings of Symposium E on Synthetic Metals for Non-linear Optics and Electronics of the 1992 E-MRS spring conference, Strasbourg, France, June 2-4 1992. Amsterdam: North-Holland, 1993.

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Eaton, Jerry P. Calibration of a linear spring-supported, vertical-component moving-coil seismometer by means of damping test and/or a current release test. Menlo Park, Calif: U.S. Dept. of the Interior, U.S. Geological Survey, 1992.

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Bosch, Siegfried. Lineare Algebra (Springer-Lehrbuch). 2nd ed. Springer, 2003.

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Bosch, Siegfried. Lineare Algebra (Springer-Lehrbuch). Springer-Verlag Berlin Heidelberg, 2001.

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Bosch, Siegfried. Lineare Algebra (Springer-Lehrbuch). 3rd ed. Springer, 2006.

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Jänich, Klaus. Lineare Algebra (Springer-Lehrbuch). Springer-Verlag Berlin Heidelberg, 2001.

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Jänich, Klaus. Lineare Algebra (Springer-Lehrbuch). 9th ed. Springer-Verlag Berlin Heidelberg, 2002.

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Jänich, Klaus. Lineare Algebra (Springer-Lehrbuch). Springer, 2003.

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Bosch, Siegfried. Lineare Algebra (Springer-Lehrbuch) (German Edition). Springer Spektrum, 2014.

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Book chapters on the topic "Linear springs"

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Chen, Jingtao, Peter Mitrouchev, Sabine Coquillart, and Franck Quaine. "Magnitude Finger Forces Analysis During Simulating Pseudo-Haptic Spring." In Lecture Notes in Mechanical Engineering, 215–20. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70566-4_34.

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AbstractThis paper focuses on finger force magnitude analysis during stiffness discrimination task. In the frame of their Study and research work MS students from the Université Grenoble Alpes specially designed an experimental bench allowing to simulate a pseudo-haptic spring. Then, a series of stiffness discrimination tests between reals springs and a pseudo-haptic spring were performed. Finger pressing forces and students’ (subjects’) perception of spring stiffness were recorded and analyzed. The analysis of psychometric curves indicates that subjects underestimate the simulated stiffness of the pseudo-haptic spring. The results also indicate that the peak of finger force applied on pseudo-haptic spring increases as the simulated stiffness increases. Moreover, it was found that the relationships between the logarithm of stiffness and the finger force were linear for the real springs and the pseudo-haptic spring. Pseudo-haptics effect being provided by specially designed isometric force feedback device, the results of this study may be useful for computer-based rehabilitation tasks designed for motor disorder patients with muscle deficiency associated with limited joint movement range or for injured athletes in the process of rehabilitation.
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Rawlings, R. M., and S. Miskimins. "Flexure Springs Applied to Low-Cost Linear Drive Cryocoolers." In Cryocoolers 11, 103–10. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/0-306-47112-4_13.

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Gong, Sanpeng, Sebastian Oberst, and Xinwen Wang. "A Non-linear Model of Rubber Shear Springs Validated by Experiments." In Nonlinear Dynamics of Structures, Systems and Devices, 319–28. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-34713-0_32.

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Mohapatra, S. C., Y. C. Guo, and C. Guedes Soares. "Analytical and experimental study on wave interaction with a horizontal floating flexible membrane supported by linear springs." In Trends in Renewable Energies Offshore, 257–66. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003360773-30.

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Uriarte, Haritz, Igor Fernández de Bustos, and Gorka Urkullu. "Implementation of Linear Springs and Dampers in a Newmark Second Order Direct Integration Method for 2D Multibody Dynamics." In Multibody Dynamics 2019, 323–31. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-23132-3_39.

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Mustapha, Khameel Bayo. "Linear Spring Elements." In Finite Element Computations in Mechanics with R, 29–50. First edition. | Boca Raton, FL : CRC Press/Taylor & Francis Group, 2018. | “A CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa plc.”: CRC Press, 2018. http://dx.doi.org/10.1201/b22398-3.

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Pluta, Mieczysław, Umar Amjad, Hermann Klinghammer, Diwaker Jha, Khurram Tarar, and Wolfgang Grill. "Dispersion Relations and Stress Dependencies of Acoustic Waves Travelling on a Chain of Point Masses Connected by Linear and Torsional Springs." In Acoustical Imaging, 253–65. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-2619-2_25.

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Babahammou, Ahmed, and Rhali Benamar. "Geometrically Non-linear Free Vibrations of Simply Supported Rectangular Plates Connected to Two Distributions of Rotational Springs at Two Opposite Edges." In Lecture Notes in Mechanical Engineering, 166–74. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-24247-3_19.

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Leugering, Günter, Tatsien Li, and Yue Wang. "1-d Wave Equations Coupled via Viscoelastic Springs and Masses: Boundary Controllability of a Quasilinear and Exponential Stabilizability of a Linear Model." In Trends in Control Theory and Partial Differential Equations, 139–56. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-17949-6_8.

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Tortorelli, Daniel A. "Sensitivity Analysis: Linear Static Spring Systems." In Advanced Design of Mechanical Systems: From Analysis to Optimization, 151–93. Vienna: Springer Vienna, 2009. http://dx.doi.org/10.1007/978-3-211-99461-0_8.

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Conference papers on the topic "Linear springs"

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Oledzki, Wieslaw J. "Smooth Non-Linear Springs, Particularly Smooth Progressive-Rate Steel Springs." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43242.

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In this paper I discuss my invention that solves the problem of designing and manufacturing springs made of elastic materials, particularly steel springs, with prescribed characteristic (dependence of flex on external load) given by a smooth (i.e. differentiable) non-linear function. The method according to the invention consists in forming an elastic body with suitably shaped regions of diversified stiffness and (possibly) diversified initial internal stresses. This suitable shape of the regions lies at the hart of the invention and is briefly discussed in the paper. I also give some formulas for the spring characteristic of the springs according to the invention and describe a method for obtaining these formulas. The paper is a companion to my patent applications “Smooth non-linear springs, particularly smooth progressive rate steel springs, progressive rate vehicle suspensions and method”, US 11/950,935 and PL P380,914.
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JIANG, W., W. JONES, K. WU, and T. WANG. "Non-linear and linear, static and dynamic analyses of helical springs." In 30th Structures, Structural Dynamics and Materials Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1989. http://dx.doi.org/10.2514/6.1989-1200.

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Soethoudt, Bram, and Just L. Herder. "Synthesis of Perfect Spring Balancers With Higher-Order Zero-Free-Length Springs." In ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-34954.

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Static balancing is a well-known technique in mechanism synthesis to achieve equilibrium throughout the range of motion, for instance to eliminate gravity from the equations of motion. Another application of static balancing is in spring-to-spring balancing where the influence of n springs on the mechanism behavior (e.g. input torque) are balanced by m other springs (n and m both non-zero positive integers). In this category of balanced mechanism, design methodology and examples exist based on zero-free-length springs, i.e. linear extension springs in which the force is proportional to the length of the spring, rather than to its elongation. The present paper will present for the first time the design of perfect spring-to-spring balancers with higher-order zero-free-length springs, i.e. springs in which the force is proportional to a (positive integer) power of its length. A general approach will be given together with four new mechanisms incorporating springs ranging from two third-order springs in the simplest example, to four equal thirteenth order springs plus one first order spring in the most complex example.
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Spaggiari, Andrea, and Eugenio Dragoni. "Multiphysics Modelling and Design of Shape Memory Alloy Wave Springs as Linear Actuators." In ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2010. http://dx.doi.org/10.1115/smasis2010-3711.

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This paper explores the merits of shape memory wave springs as powering elements of solid state actuators. Advantages and disadvantages of the wave construction in comparison to the traditional helical shape are presented and discussed by means of dimensionless functions. The main assets of the wave springs are the higher electrical resistance (leading to simpler electrical drives) and the lower cooling time (leading to enhanced working frequency). The wave geometry is also superior in purely mechanical terms to the helical counterpart when axial space is at a premium. A step-by-step design procedure is proposed, leading to the optimal wave spring meeting the multiphysics design specifications and constraints. A case study is finally reported, showing the application of shape memory wave springs to the design of a telescopic linear actuator.
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Poltschak, Florian, and Peter Ebetshuber. "Design of integrated magnetic springs for linear oscillatory actuators." In 2016 XXII International Conference on Electrical Machines (ICEM). IEEE, 2016. http://dx.doi.org/10.1109/icelmach.2016.7732607.

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Rawlings, Richard M., and Scott M. Miskimins. "Flexure springs applied to low-cost linear drive cryocoolers." In International Symposium on Optical Science and Technology, edited by Bjorn F. Andresen, Gabor F. Fulop, and Marija Strojnik. SPIE, 2000. http://dx.doi.org/10.1117/12.409882.

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Maharjan, Dipesh, Md Shaheen Shah, Abdelsalam Abugharara, and Stephen Butt. "Calculating Frictional Losses in Belleville Springs by Linear Interpolation." In Canadian Society for Mechanical Engineering International Congress (2020 : Charlottetown, PE). Charlottetown, P.E.I.: University of Prince Edward Island. Robertson Library, 2020. http://dx.doi.org/10.32393/csme.2020.1287.

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Al-Otaibi, Z. S., and A. G. Jack. "Spiral flexure springs in single phase linear-resonant motors." In 2007 42nd International Universities Power Engineering Conference. IEEE, 2007. http://dx.doi.org/10.1109/upec.2007.4468943.

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Huang, Shuguang, and Joseph M. Schimmels. "The Realizable Space of Spatial Stiffnesses Achieved With a Parallel Connection of Simple Springs." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0437.

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Abstract In this paper, we identify the space of spatial compliant behavior that can be achieved through the use of simple springs connected in parallel to a single rigid body. Here, the expression “simple spring” refers to the set of compliant relations associated with purely translational springs and purely rotational springs. We show that, regardless of the number of springs used, there exists a subspace within the 21 dimensional symmetric spatial stiffness matrix space that cannot be reached by a parallel simple spring system. The subspace of “realizable” spatial stiffness matrices achieved with parallel simple springs is 20 dimensional and is defined by a linear necessary and sufficient condition on the positive semidefinite stiffness matrix. We show that any full-rank spatial stiffness matrix satisfying the condition can be realized using only line springs.
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Ummaneni, Ravindra Babu, Caroline Jaillot, Robert Nilssen, and J. E. Brennvall. "Experimental characterisation of linear permanent magnet actuator with gas springs." In 2009 IEEE International Electric Machines and Drives Conference (IEMDC). IEEE, 2009. http://dx.doi.org/10.1109/iemdc.2009.5075232.

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Reports on the topic "Linear springs"

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Stastny, Petr, Robert Roczniok, Daniel Cleather, Martin Musalek, Dominik Novak, and Michal Vagner. Straight speed and acceleration optimal distances and reference values. A systematic review, and meta-analyses. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, May 2022. http://dx.doi.org/10.37766/inplasy2022.5.0010.

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Review question / Objective: To summarize the sprint reference acceleration and speed values for different sprint distances and suggest optimal unification of ice-hockey straight sprint testing. Eligibility criteria: The title and abstract screening was done by two researchers (PS and RR) who selected a set of articles for full text screening, where the inclusion criteria were: 1) male or female ice-hockey players; 2) any cross-sectional or intervention study; 3) tests of ice-hockey sprinting over any distance or any battery of conditioning tests that included straight-line sprints; and, 4) results reported straight-line sprint distance, speed, time, or acceleration. In the case of disagreement between the evaluating authors, the final decision was made by a third author (MV).The full text screening exclusion criteria were: 1) if the article was not in English; 2) the testing did not include straight-line sprinting; 3) the reported values did not include data distribution; 4) the study reported only maximum speed without skating time or average speed; 5) the end of the sprint was defined by the point the player stopped sprinting; 6) the measurement was made with a stopwatch; and, 7) the study had high bias estimation. The maximum speed test was not included due to the uncertain velocity conditions at beginning of testing distance. The bias estimation was performed using the JBI (Joanna Briggs Institute) Critical Appraisal Checklist for Analytical Cross Sectional Studies (supplementary material 1).
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Johnson, B. H. Thin flat plate with linear spring as mechanical stop. Final report. Office of Scientific and Technical Information (OSTI), June 1997. http://dx.doi.org/10.2172/527570.

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Abbo, Shahal, Hongbin Zhang, Clarice Coyne, Amir Sherman, Dan Shtienberg, and George J. Vandemark. Winter chickpea; towards a new winter pulse for the semiarid Pacific Northwest and wider adaptation in the Mediterranean basin. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7597909.bard.

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Original objectives: [a] Screen an array of chickpea and wild annual Cicer germplasm for winter survival. [b] Genetic analysis of winter hardiness in domesticated x wild chickpea crosses. [c] Genetic analysis of vernalization response in domesticated x wild chickpea crosses. [d] Digital expression analysis of a core selection of breeding and germplasm lines of chickpea that differ in winter hardiness and vernalization. [e] Identification of the genes involved in the chickpea winter hardiness and vernalization and construction of gene network controlling these traits. [f] Assessing the phenotypic and genetic correlations between winter hardiness, vernalization response and Ascochyta blight response in chickpea. The complexity of the vernalization response and the inefficiency of our selection experiments (below) required quitting the work on ascochyta response in the framework of this project. Background to the subject: Since its introduction to the Palouse region of WA and Idaho, and the northern Great Plains, chickpea has been a spring rotation legume due to lack of winter hardiness. The short growing season of spring chickpea limits its grain yield and leaves relatively little stubble residue for combating soil erosion. In Israel, chilling temperatures limit pod setting in early springs and narrow the effective reproductive time window of the crop. Winter hardiness and vernalization response of chickpea alleles were lost due to a series of evolutionary bottlenecks; however, such alleles are prevalent in its wild progenitor’s genepool. Major conclusions, solutions, achievements: It appears that both vernalization response and winter hardiness are polygenic traits in the wild-domesticated chickpea genepool. The main conclusion from the fieldwork in Israel is that selection of domesticated winter hardy and vernalization responsive types should be conducted in late flowering and late maturity backgrounds to minimize interference by daylength and temperature response alleles (see our Plant Breeding paper on the subject). The main conclusion from the US winter-hardiness studies is that excellent lines have been identified for germplasm release and continued genetic study. Several of the lines have good seed size and growth habit that will be useful for introgressing winter-hardiness into current chickpea cultivars to develop releases for autumn sowing. We sequenced the transcriptomes and profiled the expression of genes in 87 samples. Differential expression analysis identified a total of 2,452 differentially expressed genes (DEGs) between vernalized plants and control plants, of which 287 were shared between two or more Cicer species studied. We cloned 498 genes controlling vernalization, named CVRN genes. Each of the CVRN genes contributes to flowering date advance (FDA) by 3.85% - 10.71%, but 413 (83%) other genes had negative effects on FDA, while only 83 (17%) had positive effects on FDA, when the plant is exposed to cold temperature. The cloned CVRN genes provide new toolkits and knowledge to develop chickpea cultivars that are suitable for autumn-sowing. Scientific & agricultural implications: Unlike the winter cereals (barley, wheat) or pea, in which a single allelic change may induce a switch from winter to spring habit, we were unable to find any evidence for such major gene action in chickpea. In agricultural terms this means that an alternative strategy must be employed in order to isolate late flowering – ascochyta resistant (winter types) domesticated forms to enable autumn sowing of chickpea in the US Great Plains. An environment was identified in U.S. (eastern Washington) where autumn-sown chickpea production is possible using the levels of winter-hardiness discovered once backcrossed into advanced cultivated material with acceptable agronomic traits. The cloned CVRN genes and identified gene networks significantly advance our understanding of molecular mechanisms underlying plant vernalization in general, and chickpea in particular, and provide a new toolkit for switching chickpea from a spring-sowing to autumn-sowing crop.
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Pais, Abraham, Steven Weinberg, Chris Quigg, Michael Riordan, Wolfgang K. H. Panofsky, and Virginia Trimble. 100 years of elementary particles [Beam Line, vol. 27, issue 1, Spring 1997]. Office of Scientific and Technical Information (OSTI), April 1997. http://dx.doi.org/10.2172/790903.

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Baron, Lisa. Post-Dorian shoreline change at Cape Hatteras National Seashore: 2019 report. National Park Service, April 2021. http://dx.doi.org/10.36967/nrr-2282127.

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In 2018 and 2019 the Southeast Coast Network (SECN), with assistance from park staff, collected long-term shoreline monitoring data at Cape Hatteras National Seashore as part of the National Park Service (NPS) Vital Signs Monitoring Program. Monitoring was conducted following methods developed by the NPS Northeast Coastal and Barrier Network and consisted of mapping the high-tide swash line using a Global Positioning System unit in the spring of each year (Psuty et al. 2010). Shoreline change was calculated using the Digital Shoreline Analysis System (DSAS) developed by the United States Geological Survey (USGS; Himmelstoss et al. 2018). Following the same field methods used for monitoring long-term shoreline change, geospatial data were collected as part of the Hurricane Dorian (or Dorian) Incident Response from September 12–16, 2019. This report summarizes the post-Dorian data and the previous two shoreline data collection efforts (spring 2019 and fall 2018).
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Schmidt, Elizabeth. Shoreline change at Fort Matanzas National Monument: 2020–2021 data summary. National Park Service, January 2022. http://dx.doi.org/10.36967/nrds-2290193.

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In 2020 and 2021 the Southeast Coast Network (SECN) collected shoreline data at Fort Matanzas National Monument as a part of the NPS Vital Signs Monitoring Program. Monitoring was conducted following methods developed by the National Park Service Northeast Barrier Coast Network and consisted of mapping the high tide swash line using a global positioning system (GPS) unit in the spring of each year (Psuty et al. 2010). Shoreline change was calculated using the Digital Shoreline Analysis System (DSAS) developed by USGS (Theiler et al. 2008). Key findings from this effort: A mean of 2,255.23 meters (7,399 feet [ft]) of shoreline were mapped from 2020 to 2021 with a mean horizontal precision of 10.73 centimeters (4.2 inches [in]) at Fort Matanzas National Monument from 2020 to 2021. In the annual shoreline change analysis, the mean shoreline distance change from spring 2020 to spring 2021 was -7.40 meters (-24.3 ft) with a standard deviation of 20.24 meters (66.40 ft). The shoreline change distance ranged from -124.73 to 35.59 meters (-409.1 to 116.7 ft). Two erosion areas and one accretion area were identified in the study area beyond the uncertainty of the data (± 10 meters [32.8 ft]). The annual shoreline change from 2020 to 2021 showed erosion on the east and west sides of A1A where the Matanzas Inlet is located. Overall, the most dynamic area of shoreline change within Fort Matanzas National Monument appeared to be on the east and west side of A1A, along the Matanzas River inlet.
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Levin, Ilan, John Thomas, Moshe Lapidot, Desmond McGrath, and Denis Persley. Resistance to Tomato yellow leaf curl virus (TYLCV) in tomato: molecular mapping and introgression of resistance to Australian genotypes. United States Department of Agriculture, October 2010. http://dx.doi.org/10.32747/2010.7613888.bard.

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Tomato yellow leaf curl virus (TYLCV) is one of the most devastating viruses of cultivated tomatoes. Although first identified in the Mediterranean region, it is now distributed world-wide. Sequence analysis of the virus by the Australian group has shown that the virus is now present in Australia. Despite the importance of the disease and extensive research on the virus, very little is known about the resistance genes (loci) that determine host resistance and susceptibility to the virus. A symptom-less resistant line, TY-172, was developed at the Volcani Center which has shown the highest resistance level among all tested varieties. Preliminary results show that TY-172 is a good candidate to confer resistance to both TYLCV and to Tomato leaf curl virus (ToLCV) in Queensland conditions. Furthermore, Segregation analysis has previously indicated that the resistance is determined by 2-3 genes. In this proposal we aimed to substantiate that TY-172 can contribute to resistance breeding against TYLCV in Queensland, to develop DNA markers to advance such resistance breeding in both Israel and Queensland, and to exploit these markers for resistant breeding in Australian and Israeli lines. To map quantitative trait loci (QTLs) controlling TYLCVresistance in TY172, appropriate segregating populations were analyzed using 69 polymorphic DNA markers spanning the entire tomato genome. Results show that TYLCV resistance in TY172 is controlled by a previously unknown major QTL, originating from the resistant line, and four additional minor QTLs. The major QTL, termed Ty-5, maps to chromosome 4 and accounts for 39.7-to-46.6% of the variation in symptom severity among segregating plants (LOD score: 33-to-35). The minor QTLs, originated either from the resistant or susceptible parents, were mapped to chromosomes 1, 7, 9 and 11, and contributed 12% to the variation in symptom severity in addition to Ty-5. Further analysis of parental lines as well as large F₁, BC₁F₁, F₂ and BC₁F₂ populations originating from crosses carried out, in reciprocal manner, between TY172 and the susceptible processing line M-82 (LA3475) during spring-summer 2010, indicated that: (1) the minor QTLs we have previously identified are in effect not reproducible, (2)Ty-5 alone can yield highly resistant plants with practically no extra-chromosomal effects, and (3) the narrow-sense heritability estimate of resistance levels, attributed to additive factors responsive to selection, does not significantly deviate from 1. All of these results point to Ty-5 as the sole resistance locus in TY172 thus significantly increasing the likelihood of its successful molecular dissection. The DNA markers developed during the course of this study were transferred together with the TY172 genotype to Queensland. TY172 was crossed to a panel of Australian genotypes and the resulting populations were subjected to segregation analysis. Results showed that resistant locus, Ty-5, is highly reproducible in the Australian conditions as well. The Australian group was also able to make improvements to the marker assays by re-designing primer pairs to provide more robust PCR fragments. The Ty-5 locus has now been introgressed into elite Australian germplasm and selection for TYLCV resistance has begun. Cumulatively, our results show that Ty-5 can be effectively used, together with the TY172 genotype to expedite TYLCV resistance breeding and improve our understanding of the genetics that underline the response of tomato to TYLCV. Contributions to agriculture include: (1) the development of tools for more efficient resistance breeding, allowing the incorporation of resistance to local tomato varieties in Australia, Israel and elsewhere; and (2) establish a solid framework for a future attempt to clone the genes that encode such resistance. The latter will enable to decipher the resistance mechanisms that could be applied to other geminiviruses in tomato and possibly in other plant species.
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Blum, Abraham, and Henry T. Nguyen. Molecular Tagging of Drought Resistance in Wheat: Osmotic Adjustment and Plant Productivity. United States Department of Agriculture, November 2002. http://dx.doi.org/10.32747/2002.7580672.bard.

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Drought stress is a major limitation to bread wheat (Triticumaestivum L.) productivity and its yield stability in arid and semi-arid regions of world including parts of Israel and the U.S. Currently, breeding for sustained yields under drought stress is totally dependent on the use of yield and several key physiological attributes as selection indices. The attempt to identify the optimal genotype by evaluating the phenotype is undermining progress in such breeding programs. Osmotic adjustment (OA) is an effective drought resistance mechanism in many crop plants. Evidence exists that there is a genetic variation for OA in wheat and that high OA capacity supports wheat yields under drought stress. The major objective of this research was to identify molecular markers (RFLPs, restriction fragment length polymorphisms; and AFLPs, amplified fragment length polymorph isms) linked to OA as a major attribute of drought resistance in wheat and thus to facilitate marker-assisted selection for drought resistance. We identified high and low OA lines of wheat and from their cross developed recombinant inbred lines (RILs) used in the molecular tagging of OA in relation to drought resistance in terms of plant production under stress. The significant positive co-segregation of OA, plant water status and yield under stress in this RIL population provided strong support for the important role of OA as a drought resistance mechanism sustaining wheat production under drought stress. This evidence was obtained in addition to the initial study of parental materials for constructing this RIL population, which also gave evidence for a strong correlation between OA and grain yield under stress. This research therefore provides conclusive evidence on the important role of OA in sustaining wheat yield under drought stress. The measurement of OA is difficult and the selection for drought resistance by the phenotypic expression of OA is practically impossible. This research provided information on the genetic basis of OA in wheat in relations to yield under stress. It provided the basic information to indicate that molecular marker assisted selection for OA in wheat is possible. The RIL population has been created by a cross between two agronomic spring wheat lines and the high OA recombinants in this population presented very high OA values, not commonly observed in wheat. These recombinants are therefore an immediate valuable genetic recourse for breeding well-adapted drought resistant wheat in Texas and Israel. We feel that this work taken as a whole eliminate the few previous speculated . doubts about the practical role of OA as an important mechanism of drought resistance in economic crop plants. As such it should open the way, in terms of both concept and the use of marker assisted selection, for improving drought resistance in wheat by deploying high osmotic adjustment.
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Blum, Abraham, Henry T. Nguyen, and N. Y. Klueva. The Genetics of Heat Shock Proteins in Wheat in Relation to Heat Tolerance and Yield. United States Department of Agriculture, August 1993. http://dx.doi.org/10.32747/1993.7568105.bard.

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Fifty six diverse spring wheat cultivars were evaluated for genetic variation and heritability for thermotolerance in terms of cell-membrane stability (CMS) and triphenyl tetrazolium chloride (TTC) reduction. The most divergent cultivars for thermotolerance (Danbata-tolerant and Nacozari-susceptible) were crossed to develop an F8 random onbred line (RIL) population. This population was evaluated for co-segragation in CMS, yield under heat stress and HSP accumulation. Further studies of thermotolerance in relations to HSP and the expression of heterosis for growth under heat stress were performed with F1 hybrids of wheat and their parental cultivars. CMS in 95 RILs ranged from 76.5% to 22.4% with 71.5% and 31.3% in Danbata and Nacozari, respectively. The population segregated with a normal distribution across the full range of the parental values. Yield and biomass under non-stress conditions during the normal winter season at Bet Dagan dit not differ between the two parental cultivar, but the range of segregation for these traits in 138 RILs was very high and distinctly transgressive with a CV of 35.3% and 42.4% among lines for biomass and yield, respectively. Mean biomass and yield of the population was reduced about twofold when grown under the hot summer conditions (irrigated) at Bet Dagan. Segregation for biomass and yield was decreased relative to the normal winter conditions with CV of 20.2% and 23.3% among lines for biomass and yield, respectively. However, contrary to non-stress conditions, the parental cultivars differed about twofold in biomass and yield under heat stress and the population segregated with normal distribution across the full range of this difference. CMS was highly and positively correlated across 79 RILs with biomass (r=0.62**) and yield (r=0.58**) under heat stress. No such correlation was obtained under the normal winter conditions. All RILs expressed a set of HSPs under heat shock (37oC for 2 h). No variation was detected among RILs in high molecular weight HSP isoforms and they were similar to the patterns of the parental cultivars. There was a surprisingly low variability in low molecular weight HSP isoforms. Only one low molecular weight and Nacozari-specific HSP isoform (belonging to HSP 16.9 family) appeared to segregate among all RILs, but it was not quantitatively correlated with any parameter of plant production under heat stress or with CMS in this population. It is concluded that this Danbata/Nacozari F8 RIL population co-segregated well for thermotolerance and yield under heat stress and that CMS could predict the relative productivity of lines under chronic heat stress. Regretfully this population did not express meaningful variability for HSP accumulation under heat shock and therefore no role could be seen for HSP in the heat tolerance of this population. In the study of seven F1 hybrids and their parent cultivars it was found that heterosis (superiority of the F1 over the best parent) for CMs was generally lower than that for growth under heat stress. Hybrids varied in the rate of heterosis for growth at normal (15o/25o) and at high (25o/35o) temperatures. In certain hybrids heterosis for growth significantly increased at high temperature as compared with normal temperature, suggesting temperature-dependent heterosis. Generally, under normal temperature, only limited qualitative variation was detected in the patterns of protein synthesis in four wheat hybrids and their parents. However, a singular protein (C47/5.88) was specifically expressed only in the most heterotic hybrid at normal temperature but not in its parent cultivars. Parental cultivars were significantly different in the sets of synthesized HSP at 37o. No qualitative changes in the patterns of protein expression under heat stress were correlated with heterosis. However, a quantitative increase in certain low molecular weight HSP (mainly H14/5.5 and H14.5.6, belonging to the HSP16.9 family) was positively associated with greater heterosis for growth at high temperature. None of these proteins were correlated with CMS across hybrids. These results support the concept of temperature-dependent heterosis for growth and a possible role for HSP 16.9 family in this respect. Finally, when all experiments are viewed together, it is encouraging to find that genetic variation in wheat yield under chronic heat stress is associated with and well predicted by CMS as an assay of thermotolerance. On the other hand the results for HSP are elusive. While very low genetic variation was expressed for HSP in the RIL population, a unique low molecular weight HSP (of the HSP 16.9 family) could be associated with temperature dependant heterosis for growth.
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10

Pstuty, Norbert, Mark Duffy, Dennis Skidds, Tanya Silveira, Andrea Habeck, Katherine Ames, and Glenn Liu. Northeast Coastal and Barrier Network Geomorphological Monitoring Protocol: Part I—Ocean Shoreline Position, Version 2. National Park Service, June 2022. http://dx.doi.org/10.36967/2293713.

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Following a review of Vital Signs – indicators of ecosystem health – in the coastal parks of the Northeast Coastal and Barrier Network (NCBN), knowledge of shoreline change was ranked as the top variable for monitoring. Shoreline change is a basic element in the management of any coastal system because it contributes to the understanding of the functioning of the natural resources and to the administration of the cultural resources within the parks. Collection of information on the vectors of change relies on the establishment of a rigorous system of protocols to monitor elements of the coastal geomorphology that are guided by three basic principles: 1) all of the elements in the protocols are to be based on scientific principles; 2) the products of the monitoring must relate to issues of importance to park management; and 3) the application of the protocols must be capable of implementation at the local level within the NCBN. Changes in ocean shoreline position are recognized as interacting with many other elements of the Ocean Beach-Dune Ecosystem and are thus both driving and responding to the variety of natural and cultural factors active at the coast at a variety of temporal and spatial scales. The direction and magnitude of shoreline change can be monitored through the application of a protocol that tracks the spatial position of the neap-tide, high tide swash line under well-defined conditions of temporal sampling. Spring and fall surveys conducted in accordance with standard operating procedures will generate consistent and comparable shoreline position data sets that can be incorporated within a data matrix and subsequently analyzed for temporal and spatial variations. The Ocean Shoreline Position Monitoring Protocol will be applied to six parks in the NCBN: Assateague Island National Seashore, Cape Cod National Seashore, Fire Island National Seashore, Gateway National Recreation Area, George Washington Birthplace National Monument, and Sagamore Hill National Historic Site. Monitoring will be accomplished with a Global Positioning System (GPS )/ Global Navigation Satellite System (GNSS) unit capable of sub-meter horizontal accuracy that is usually mounted on an off-road vehicle and driven along the swash line. Under the guidance of a set of Standard Operating Procedures (SOPs) (Psuty et al., 2022), the monitoring will generate comparable data sets. The protocol will produce shoreline change metrics following the methodology of the Digital Shoreline Analysis System developed by the United States Geological Survey. Annual Data Summaries and Trend Reports will present and analyze the collected data sets. All collected data will undergo rigorous quality-assurance and quality-control procedures and will be archived at the offices of the NCBN. All monitoring products will be made available via the National Park Service’s Integrated Resource Management Applications Portal.
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