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Articles de revues sur le sujet « Alternate bar »

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Auteur : Grafiati

Publié le 14 mars 2023

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1

Venditti, J. G., P. A. Nelson, J. T. Minear, J. Wooster et W. E. Dietrich. « Alternate bar response to sediment supply termination ». Journal of Geophysical Research : Earth Surface 117, F2 (juin 2012) : n/a. http://dx.doi.org/10.1029/2011jf002254.

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2

Cheng, Yunshuo, et Ana Maria Ferreira da Silva. « Empirical Equation for Determination of Alternate Bar Height ». Journal of Hydraulic Engineering 145, n^o 11 (novembre 2019) : 04019037. http://dx.doi.org/10.1061/(asce)hy.1943-7900.0001633.

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3

Calvani, Giulio, Simona Francalanci et Luca Solari. « Flume experiments on vegetated alternate bars ». E3S Web of Conferences 40 (2018) : 02034. http://dx.doi.org/10.1051/e3sconf/20184002034.

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The planform morphology of a river reach is the result of the combined actions of sediment motion (erosion, transport and deposition), hydrological regime, development and growth of vegetation. However, the interactions among these processes are still poorly understood and rarely investigated in laboratory flume experiments. In these experiments and also in numerical modelling, vegetation is usually represented by rigid cylinders, although it is widely recognized that this schematization cannot reproduce the effects of root stabilization and binding on riverbed sediment. In this work, we focus on the effects of added vegetation on morphological dynamics of alternate bars in a straight channel by means of flume experiments. We performed laboratory experiments reproducing hydraulic conditions that are typical of gravel bed rivers, in terms of water depth, bed slope and bed load; these conditions led to the formation of freely migrating alternate bars. We then employed rigid vegetation that was deployed on the reproduced alternate bars according to field observations. Various vegetation scenarios, in terms of density and spatial arrangement, were deployed in the flume experiments such to mimic different maintenance strategies. Results show the effects of rigid vegetation on the alternate bar configuration on the overall topographic pattern, the main alternate bar characteristics (such as amplitude and wavelength) and migration rate.

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4

Dai, Huang, Toshiki Iwasaki et Yasuyuki Shimizu. « Effect of Sediment Supply on Morphodynamics of Free Alternate Bars : Insights from Hydrograph Boundary Layer ». Water 13, n^o 23 (4 décembre 2021) : 3437. http://dx.doi.org/10.3390/w13233437.

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Sediment supply plays an essential role in river morphology. However, the specific impact of sediment supply on river morphology is not apparent. According to the hydrograph boundary layer (HBL) concept, upstream riverbed changes caused by the imbalance between sediment supply and the capacity can propagate only a limited length and have a negligible effect on the riverbed beyond such a short length. We performed a two-dimensional morphodynamic calculation to test the concept of HBL, which was proposed under a one-dimensional simulation, meaning that the concept of HBL is still valid for plane changes in river morphology. We employed an unsteady flow with equilibrium or constant sediment supply in a straight, modeled gravel-bedded channel with an unerodible bank to simulate alternate bar morphodynamics. The results show that regardless of the sediment supply condition, the alternate bar features formed downstream of the HBL are considerably similar. This suggests that sediment disturbance at the upstream end has a negligible effect on the mobile-bed dynamic processes, including alternate bar formation and development downstream of the HBL.

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5

Jourdain, Camille, Nicolas Claude, Germain Antoine, Pablo Tassi et Florian Cordier. « Influence of flood regime on riparian vegetation dynamics in rivers with alternate bars ». E3S Web of Conferences 40 (2018) : 02025. http://dx.doi.org/10.1051/e3sconf/20184002025.

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Throughout the 20th century, many rivers worldwide have undergone important riparian vegetation encroachment, which can be problematic in terms of flood risks and biodiversity. Nowadays, controlled floods is often considered as a management option in anthropized rivers, with the aim of limiting vegetation encroachment within river channels, as well as maintaining a diverse habitat by reactivating natural channel dynamics. In this context, this study aims at investigating the influence of different flood regimes on river bar vegetation development and dynamics, focussing on alternate bar systems which are typically found in embanked streams. This question has been addressed through two-dimensional bio-morphodynamic modeling of a simplified gravel bed river reach. Four hydrological scenarios with different flood peak discharges have been run for 50 years. For all scenarios, a steady increase in vegetation cover strongly impacts the evolution of bar morphology, until a relatively stable equilibrium is reached after one to three decades. Numerical results suggest that vegetation development on bars is associated to an increase in bar wavelength and a decrease in bar width. Higher peak flood discharges lead to narrower and longer bars, and a longer adjustment duration. When vegetation cover is fully developed, interannual flood variability seems crucial to maintain bedform and vegetation turnover.

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6

WATANABE, Yasuharu, et Marco TUBINO. « Influence of Bed Load and Suspended Load on Alternate Bar ». PROCEEDINGS OF HYDRAULIC ENGINEERING 36 (1992) : 7–14. http://dx.doi.org/10.2208/prohe.36.7.

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7

Jaballah, Mohamed, Benoît Camenen, Lionel Pénard et André Paquier. « Alternate bar development in an alpine river following engineering works ». Advances in Water Resources 81 (juillet 2015) : 103–13. http://dx.doi.org/10.1016/j.advwatres.2015.03.003.

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8

Redolfi, Marco, Matilde Welber, Mattia Carlin, Marco Tubino et Walter Bertoldi. « Morphometric properties of alternate bars and water discharge : a laboratory investigation ». Earth Surface Dynamics 8, n^o 3 (23 septembre 2020) : 789–808. http://dx.doi.org/10.5194/esurf-8-789-2020.

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Abstract. The formation of alternate bars in straightened river reaches represents a fundamental process of river morphodynamics that has received great attention in the last decades. It is well-established that migrating alternate bars arise from an autogenic instability mechanism occurring when the channel width-to-depth ratio is sufficiently large. While several empirical and theoretical relations are available for predicting how bar height and length depend on the key dimensionless parameters, there is a lack of direct, quantitative information about the dependence of bar properties on flow discharge. We performed a series of experiments in a long, mobile-bed flume with fixed and straight banks at different discharges. The self-formed bed topography was surveyed, different metrics were analyzed to obtain quantitative information about bar height and shape, and results were interpreted in the light of existing theoretical models. The analysis reveals that the shape of alternate bars highly depends on their formative discharge, with remarkable variations in the harmonic composition and a strong decreasing trend of the skewness of the bed elevation. Similarly, the height of alternate bars clearly decreases with the water discharge, in quantitative agreement with theoretical predictions. However, the disappearance of bars when discharge exceeds a critical threshold is not as sharp as expected due to the formation of so-called “diagonal bars”. This work provides basic information for modeling and interpreting short-term morphological variations during individual flood events and long-term trajectories due to alterations of the hydrological regime.

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9

Welford, Mark R. « A field test of tubino's (1991) model of alternate bar formation ». Earth Surface Processes and Landforms 19, n^o 4 (juin 1994) : 287–97. http://dx.doi.org/10.1002/esp.3290190402.

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10

LANZONI, STEFANO, et MARCO TUBINO. « Grain sorting and bar instability ». Journal of Fluid Mechanics 393 (25 août 1999) : 149–74. http://dx.doi.org/10.1017/s0022112099005583.

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A two-dimensional model of flow and bed topography is proposed to investigate the effect of sediment heterogeneity on the development of alternate bars. Within the context of a linear stability theory the flow field, the bed topography and the grain size distribution function are perturbed leading to an integro-differential linear eigenvalue problem. It is shown that the selective transport of different grain size fractions and the resulting spatial pattern of sorting may appreciably affect the balance between stabilizing and destabilizing actions which govern bar instability. Theoretical results suggest that sediment heterogeneity leads to a damping of both growth rate and migration speed of bars, while bar wavelength is shortened with respect to the case of uniform sediment. The above findings conform, at least qualitatively, to the experimentally detected reduction of bar height, length and celerity. The observed tendency of coarser particles to pile up towards bar crests is also reproduced by theoretical results.

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11

NAKAMURA, Hajimu, Hiroshi TAKEBAYASHI et Kenichi HASHIMOTO. « EXPERIMENTAL STUDY ON FORMATION OF DYNAMIC STABLE ALTERNATE BAR USING SPUR DIKES. » Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 76, n^o 2 (2020) : I_1213—I_1218. http://dx.doi.org/10.2208/jscejhe.76.2_i_1213.

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12

Gogate, Gunesh R., et Sanjay B. Matekar. « Optimum synthesis of motion generating four-bar mechanisms using alternate error functions ». Mechanism and Machine Theory 54 (août 2012) : 41–61. http://dx.doi.org/10.1016/j.mechmachtheory.2012.03.007.

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13

Bankert, Andrew R., et Peter A. Nelson. « Alternate bar dynamics in response to increases and decreases of sediment supply ». Sedimentology 65, n^o 3 (24 août 2017) : 702–20. http://dx.doi.org/10.1111/sed.12399.

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14

Eekhout, J. P. C., A. J. F. Hoitink et E. Mosselman. « Field experiment on alternate bar development in a straight sand-bed stream ». Water Resources Research 49, n^o 12 (décembre 2013) : 8357–69. http://dx.doi.org/10.1002/2013wr014259.

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15

Okitsu, Takara, Toshiki Iwasaki, Tomoko Kyuka et Yasuyuki Shimizu. « The Role of Large-Scale Bedforms in Driftwood Storage Mechanism in Rivers ». Water 13, n^o 6 (16 mars 2021) : 811. http://dx.doi.org/10.3390/w13060811.

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The quantification of driftwood deposition in rivers is important for understanding the total budget of driftwood at the watershed scale; however, it remains unclear how such driftwood storage in rivers contributes to the overall system because of the difficulties in undertaking field measurements. Herein, we perform numerical simulations of driftwood deposition within an idealized river reach with a sand-bed, to describe the role of large-scale bedforms, more specifically, alternate bars, multiple bars, and braiding, in driftwood storage in rivers. The numerical model we propose here is a coupling model involving a Lagrangian-type driftwood model and an Eulerian two-dimensional morphodynamic model for simulating large-scale bedforms (i.e., bars and braiding). The results show that the channel with a braiding pattern provides a wide area with enhanced capacity for deposition of driftwood, characterized by exposed mid-channel or in-channel bars, leading to high driftwood storage. The alternate bar is also a large bedform representing a sediment depositional element in rivers; however, because of the narrow exposed bar area and its downstream-migrating feature during floods, the alternate bars seem to contribute less to driftwood deposition in rivers. This suggests that the role of multiple bars and braiding is critically important for the driftwood deposition in rivers.

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16

Schielen, R., A. Doelman et H. E. de Swart. « On the nonlinear dynamics of free bars in straight channels ». Journal of Fluid Mechanics 252 (juillet 1993) : 325–56. http://dx.doi.org/10.1017/s0022112093003787.

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A simple morphological model is considered which describes the interaction between a unidirectional flow and an erodible bed in a straight channel. For sufficiently large values of the width-depth ratio of the channel the basic state, i.e. a uniform current over a flat bottom, is unstable. At near-critical conditions growing perturbations are confined to a narrow spectrum and the bed profile has an alternate bar structure propagating in the downstream direction. The timescale associated with the amplitude growth is large compared to the characteristic period of the bars. Based on these observations a weakly nonlinear analysis is presented which results in a Ginzburg-Landau equation. It describes the nonlinear evolution of the envelope amplitude of the group of marginally unstable alternate bars. Asymptotic results of its coefficients are presented as perturbation series in the small drag coefficient of the channel. In contrast to the Landau equation, described by Colombini et al. (1987), this amplitude equation also allows for spatial modulations due to the dispersive properties of the wave packet. It is demonstrated rigorously that the periodic bar pattern can become unstable through this effect, provided the bed is dune covered, and for realistic values of the other physical parameters. Otherwise, it is found that the periodic bar pattern found by Colombini et al. (1987) is stable. Assuming periodic behaviour of the envelope wave in a frame moving with the group velocity, simulations of the dynamics of the Ginzburg-Landau equation using spectral models are carried out, and it is shown that quasi-periodic behaviour of the bar pattern appears.

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17

Gupta, K. C. « Rotatability Considerations for Spherical Four-Bar Linkages With Applications to Robot Wrist Design ». Journal of Mechanisms, Transmissions, and Automation in Design 108, n^o 3 (1 septembre 1986) : 387–91. http://dx.doi.org/10.1115/1.3258744.

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The following result for spherical four-bar mechanisms is proved: Let all links of a spherical four-bar linkage be in the range [0, π]. Consider two linkages—one primary (p) and another secondary (s) according to the condition αip + αfp < αis + αfs where αs = π − αp. Then the input link is fully rotatable iff αip + αfp < αc + α0, |αip − αfp| > |αc − α0| and αip + αfp + αc + α0 < 2π. An alternate form of this result also is developed. Applications of these results in determining full or partial rotatability of grippers in spherical robot wrists are discussed.

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18

UCHIJIMA, Kunihide, et Hiroshi HAYAKAWA. « A Study on Similarity Law of Distorted River Models with Alternate Bar Beds. » Doboku Gakkai Ronbunshu, n^o 479 (1993) : 71–79. http://dx.doi.org/10.2208/jscej.1993.479_71.

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19

TAKEBAYASHI, Hiroshi, et Shinji EGASHIRA. « SPATIOTEMPORAL CHANGE CHARACTERISTICS OF ALTERNATE BAR GEOMETORY ON BED WITH NON-UNIFORM SEDIMENT ». PROCEEDINGS OF HYDRAULIC ENGINEERING 51 (2007) : 1033–38. http://dx.doi.org/10.2208/prohe.51.1033.

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MIWA, Hiroshi, Atsuyuki DAIDO et Tomohito KATAYAMA. « EFFECTS OF WATER AND SEDIMENT DISCHARGE CONDITIONS ON VARIATION IN ALTERNATE BAR MORPHOLOGY ». PROCEEDINGS OF HYDRAULIC ENGINEERING 51 (2007) : 1051–56. http://dx.doi.org/10.2208/prohe.51.1051.

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21

Obana, Makiko, Yuji Toda et Tetsuro Tsujimoto. « Nutrient Transport and Change Driven by Sub-surface Flow in Alternate Bar Reach ». Procedia Environmental Sciences 13 (2012) : 1246–53. http://dx.doi.org/10.1016/j.proenv.2012.01.118.

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22

Qian, Honglu, Zhixian Cao, Huaihan Liu et Gareth Pender. « Numerical modelling of alternate bar formation, development and sediment sorting in straight channels ». Earth Surface Processes and Landforms 42, n^o 4 (25 juillet 2016) : 555–74. http://dx.doi.org/10.1002/esp.3988.

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23

Crawford, Bridget J. « Menstruation and the Bar Exam : Unconstitutional Tampon Bans ». Columbia Journal of Gender and Law 41, n^o 1 (8 novembre 2021) : 63–74. http://dx.doi.org/10.52214/cjgl.v41i1.8822.

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Some states have policies that prevent bar exam candidates from bringing their own menstrual products to the test. Via social media, awareness of these policies achieved new heights in the weeks leading up to the July 2020 bar exam. A small number of jurisdictions responded to public criticism by permitting test takers to bring menstrual products with them to the exam, whether administered traditionally or remotely in response to the COVID-19 pandemic. Not all states have adopted permissive policies, however. This Essay explains why outright bans on menstrual products at the bar exam likely are unconstitutional. So-called alternate policies, such as making menstrual products available in women’s restrooms, are inadequate. Only a “free-carry” policy for menstrual products is consistent with welcoming all qualified candidates to the legal profession, without regard to biology.

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24

Egorov, Vladimir, et Grigory Belyy. « Calculation of Combined Structure and Installation Roof Systems Taking into Account Structural Nonlinearity Factor ». Applied Mechanics and Materials 725-726 (janvier 2015) : 734–39. http://dx.doi.org/10.4028/www.scientific.net/amm.725-726.734.

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Stress and strain state of hybrid (combined) systems including flexible and rigid elements is studied in the article. Theoretical approach is presented. The feature of the systems studied is described, i.e. structural nonlinearity. Numerical analysis is presented. It is pointed out that vibrations of such structures upon conditions of resonance differ from those of classical bar structures, i.e. if for rigid bar systems the amplitudes of vibration at resonant disturbance increase monotonously, in combined (hybrid) system alternate switching off tie-bars stabilizes the amplitude of vibration at a certain value and transfers vibrations in the beating mode that can be considered as an internal vibration absorber.

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Egorov, Vladimir, et Grigory Belyy. « Nonlinear properties of hybrid construction of coatings of buildings and structures ». E3S Web of Conferences 217 (2020) : 01001. http://dx.doi.org/10.1051/e3sconf/202021701001.

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Stress and strain state of hybrid (combined) systems including flexible and rigid elements is studied in the article. Theoretical approach is presented. The feature of the systems studied is described, i.e. structural nonlinearity. Numerical analysis is presented. It is pointed out that vibrations of such structures upon conditions of resonance differ from those of classical bar structures, i.e. if for rigid bar systems the amplitudes of vibration at resonant disturbance increase monotonously, in combined (hybrid) system alternate switching off tie-bars stabilizes the amplitude of vibration at a certain value and transfers vibrations in the beating mode that can be considered as an internal vibration absorber.

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26

Blondeaux, P., et G. Seminara. « A unified bar–bend theory of river meanders ». Journal of Fluid Mechanics 157 (août 1985) : 449–70. http://dx.doi.org/10.1017/s0022112085002440.

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A two-dimensional model of flow and bed topography in sinuous channels with erodible boundaries is developed and applied in order to investigate the mechanism of meander initiation. By reexamining the problem recently tackled by Ikeda, Parker & Sawai (1981), a previously undiscovered ‘resonance’ phenomenon is detected which occurs when the values of the relevant parameters fall within a neighbourhood of certain critical values. It is suggested that the above resonance controls the bend growth, and it is shown that it is connected in some sense with bar instability. In fact, by performing a linear stability analysis of flow in straight erodible channels, resonant flow in sinuous channels is shown to occur when curvature ‘forces’ a ‘natural’ solution represented by approximately steady perturbations of the alternate bar type. A comparison with experimental observations appears to support the idea that resonance is associated with meander formation.

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27

Salleh, Mohd Zulkhairi Mat, Zulkiflee Ibrahim, Radzuan Saari, Mazlin Jumain, Zulhilmi Ismail, Muhamad Effandi Mohd Shariff, Nurdalina Syuhada Zulkifli et Che Ku Ahmad Lukman Mazlan. « Experiment on fundamental behaviours of wavelength and height of vegetated alternate bar in river ». IOP Conference Series : Earth and Environmental Science 646, n^o 1 (1 janvier 2021) : 012037. http://dx.doi.org/10.1088/1755-1315/646/1/012037.

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28

ONDA, Shinichiro, Masaharu YASUBA et Takashi HOSODA. « 3D NUMERICAL SIMULATION OF ALTERNATE BAR FORMATION AND RIVER CHANNEL PROCESS WITH BANK EROSION ». Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 74, n^o 5 (2018) : I_991—I_996. http://dx.doi.org/10.2208/jscejhe.74.5_i_991.

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TODO, Masaki, et Shoji FUKUOKA. « STUDY ON ALTERNATE BAR TRANSFORMATION AND WATER-LEVEL CHANGES UNDER SHARP-PEAKED FLOOD HYDROGRAPHS ». PROCEEDINGS OF HYDRAULIC ENGINEERING 48 (2004) : 1015–20. http://dx.doi.org/10.2208/prohe.48.1015.

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Bottin, Matteo, Riccardo Minto et Giulio Rosati. « Design of the Drive Mechanism of a Rotating Feeding Device ». Machines 10, n^o 12 (4 décembre 2022) : 1160. http://dx.doi.org/10.3390/machines10121160.

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Component batching can be a source of time waste in specific industrial applications, such as kitting. Kitting operations are usually performed by hoppers, but other devices can be used to optimize the process. In a previous work, a rotary device has been proved to be more efficient than hoppers; such a device allows the kitting and releasing of the components in a single rotatory movement, while traditional hoppers require at least two movements. In this paper, an improvement of such feeding device is proposed. The movement of the rotary device is driven by a four-bar linkage mechanism which is designed through functional synthesis. Thank to the four-bar linkage mechanism, the alternate motion of the rotary distributor is derived from the constant speed of the motor.

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Somanchi, Naga Sarada, Sri Rama R. Devi et Ravi Gugulothu. « Experimental Investigations on Heat Transfer Enhancement in a Horizontal Tube Using Converging and Diverging Conical Strip Inserts ». Applied Mechanics and Materials 592-594 (juillet 2014) : 1590–95. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.1590.

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The present work deals with the results of the experimental investigations carried out on augmentation of turbulent flow heat transfer in a horizontal circular tube by means of tube inserts, with air as working fluid. Experiments were carried out initially for the plain tube (without tube inserts). The Nusselt number and friction factor obtained experimentally were validated against those obtained from theoretical correlations. Secondly experimental investigations using three kinds of tube inserts namely Rectangular bar with diverging conical strips, Rectangular bar with converging conical strips, Rectangular bar with alternate converging diverging conical strips were carried out to estimate the enhancement of heat transfer rate for air in the presence of inserts. The Reynolds number ranged from 8000 to 19000. In the presence of inserts, Nusselt number and pressure drop increased, overall enhancement ratio is calculated to determine the optimum geometry of the tube insert. Based on experimental investigations, it is observed that, the enhancement of heat transfer using Rectangular bar with converging and diverging conical strips is more effective compared to other inserts. Key words: Heat transfer, enhancement, turbulent flow, conical strip inserts, friction factor, pressure drop.

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Fu, Tao, Jing Wang, Moran Levin, Qing Su, Dongguo Li et Junfa Li. « Fusional Vergence Detected by Prism Bar and Synoptophore in Chinese Childhood Intermittent Exotropia ». Journal of Ophthalmology 2015 (2015) : 1–6. http://dx.doi.org/10.1155/2015/987048.

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Purpose. To measure the changes in fusional vergence in Chinese children with intermittent exotropia (IXT) and the association with the control of IXT.Methods. Ninety-two patients with IXT (8–15 years old) were compared with 86 controls. Exodeviation control was evaluated using the Revised Newcastle Control Score. Angle of deviation was measured using prism and alternate cover testing at distance and near. Fusional vergence was measured using prism bar and synoptophore. This study was registered withChiCTR-RCC-13003920.Results. Using prism bar, convergence break points were lower whereas divergence break points were higher in children with IXT at distance (P<0.001) and near (P<0.001) compared with controls. There was no significant difference in mean divergence amplitudes between the two groups when testing using a synoptophore (P=0.53). In children with IXT, the distance between recovery point and break point in both convergence (distance:P=0.02; near:P=0.02) and divergence (distance:P<0.001; near:P<0.001) was larger than controls when detected by prism bar and synoptophore (convergence:P=0.005; divergence:P=0.006).Conclusions. Children with IXT have reduced convergence amplitudes as detected by both prism bar and synoptophore.

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Policarpo, Hugo, M. M. Neves et A. M. R. Ribeiro. « An Experimental Characterization of Cork Storage Modulus for Cork-Steel Applications in Vibration Attenuation ». Materials Science Forum 636-637 (janvier 2010) : 1199–205. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.1199.

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This study presents an experimental characterization of cork storage modulus used to model the vibration response of bars built using alternate layers of cork and steel. In the experimental setup, the specimen was suspended from a fixed support by two thin lines while a shaker was suspended from a mobile support by metallic chains. The shaker was connected to the bar specimen through a force transducer imposing a dynamical deformation that propagates through the specimen. An accelerometer in the opposite extremity of the bar measures the corresponding vibration response and the cork storage modulus is then obtained from the first peak of this frequency response. The proposed methodology successfully characterized the storage modulus of the cork material used in the multilaminated periodic bars. The results obtained illustrate a satisfactory correlation between

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Schuster, W. J., E. Moreno et J. G. Fernández-Trincado. « Resonant Trapping of the Moving Groups G18-39 and G21-22 in the Galactic Halo ». Proceedings of the International Astronomical Union 14, S344 (août 2018) : 134–38. http://dx.doi.org/10.1017/s174392131800683x.

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AbstractOrbital resonances in the Galactic halo have been studied using the Galactic mass model of Pichardo et al. (2003, 2004), including a Galactic bar. For the two moving groups of the Galactic halo, G18-39 and G21-22 (Silva et al. 2012), the majority of stars in both groups appear trapped in two resonances over the Galactic plane, generated by the bar. We have taken the rotation speed of the bar, Ωb, as 45-55 km s-1 kpc-1. So, these two moving groups are part of stellar supergroups which populate these two resonances. The position of these two groups in the Bottlinger diagram can be explained by the mean (U,V) field generated by these two resonances crossing the solar vicinity, in contrast with the alternate explanation of Silva et al. (2012), based on the simulations of Meza et al. (2005), that these two groups, seen as two peaks in the U Galactic velocity, have been created by the accretion of a dwarf galaxy by the Milky Way, such as that of Ω Centauri.

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Stern, Rachel E., et Lawrence J. Liu. « The Good Lawyer : State-Led Professional Socialization in Contemporary China ». Law & ; Social Inquiry 45, n^o 1 (11 novembre 2019) : 226–48. http://dx.doi.org/10.1017/lsi.2019.55.

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How do authoritarian states define and communicate notions of appropriate work conduct and professional excellence? This article examines three channels of communication used by the Chinese state to signal professional expectations to the bar: the bar exam, the administrative rules governing lawyers, and the state-sanctioned National Outstanding Lawyer Award. We find that China’s state narrative about “the good lawyer” celebrates lawyers willing to work closely with the authorities and asks more stringent critics to separate private beliefs from public behavior. In contrast to assumptions often made in research on authoritarian law, this article highlights how lawyers can participate in politics without opposing the regime and how much work goes into curating an appealing state strand of legal professionalism rather than relying on coercion alone. We end with a call for future work on “varieties of legal professionalism” to better understand which state signals are most visible and persuasive to different segments of the Chinese bar, as well as the conditions under which alternate ideas about professionalism gain traction.

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Xu, Wen Feng, Zeng Lian Li, Kui Li et Xiao Ling Liao. « Preparation and Study of Biomimetic Ring CoCl₂/CS Biological Bar ». Advanced Materials Research 647 (janvier 2013) : 368–73. http://dx.doi.org/10.4028/www.scientific.net/amr.647.368.

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Exploring an effective replacement material of bone transplantation to repair bone defect is the hot topic in bone defect therapy at present. The biomimetic materials will be the main dircetion. Chitosan, the N-deacetylated derivative of chitin, has been regarded as suitable materials because of its biocompatibility, biodegradability, reliability and wide sources, which is the next generation of promising materials for tissue engineering. This study introduce the best CoCl2_-Chitosan-gel-sticks of different concentrations prepared by using the in-situ Precipitation Method and Alternate deposition Method. This investigation progeny will have a wide range of applications in biological materials field and other fields.

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Raste, Hrishikesh Y., Ameya P. Apte et Gunesh R. Gogate. « OPTIMUM SYNTHESIS OF PATH GENERATING ADJUSTABLE MECHANISMS WITH IMPROVED SLOPE CONTINUITY OF THE CONTROL PARAMETER ». Transactions of the Canadian Society for Mechanical Engineering 37, n^o 2 (juin 2013) : 197–214. http://dx.doi.org/10.1139/tcsme-2013-0012.

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Adjustable mechanisms have been studied in literature for path and function generation. In this paper, a path generating four-bar mechanism with an alternate single parameter adjustment is proposed and optimally synthesized, using the method of Differential Evolution. Two new approaches are developed, aimed at improving the slope continuity characteristic of the control parameter. Optimum synthesis results are obtained using the proposed approaches. The results show that the proposed approaches lead to improved slope continuity characteristics of the control parameter.

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QI, Lukuan, Hiroshi SEKI et Kotoyoshi TAKAGI. « Study on corrosion of reinforcing bar due to concrete neutralization under alternate drying and wetting conditions. » Doboku Gakkai Ronbunshu, n^o 697 (2002) : 1–11. http://dx.doi.org/10.2208/jscej.2002.697_1.

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Barðdal, Jóhanna, Thórhallur Eythórsson et Tonya Kim Dewey. « The alternating predicate puzzle ». Constructions and Frames 11, n^o 1 (3 juillet 2019) : 107–70. http://dx.doi.org/10.1075/cf.00025.bar.

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Abstract A long-standing divide between Icelandic and German in the literature takes for granted that there are non-nominative subjects in Icelandic, while corresponding arguments in German have been analyzed as objects (Zaenen et al. 1985; Sigurðsson 1989). This is based on two differences between these languages: (a) differences with regard to control and conjunction reduction and (b) apparent subject behavior of the nominative in dat-nom constructions in German. This article focuses on the latter, introducing into the discussion the concept of alternating predicates, that is, dat-nom predicates that systematically alternate between two diametrically-opposed argument structure constructions, dat-nom and nom-dat. A comparison between Icelandic and German shows that Icelandic dat-nom predicates are of two types, a non-alternating líka type and an alternating falla í geð type, whereas German seems to exhibit only the alternating type. On this assumption, the apparent subject behavior of the nominative in German is easily explained, since such occurrences in fact involve the nom-dat construction and not the dat-nom construction. Therefore, the subject behavior of the nominative in nom-dat constructions does not invalidate a subject analysis of the dative in dat-nom constructions in German. The analysis is couched in the framework of construction grammar.

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Lee, Jun-Kyu, Sung-Min Wi, Jin-Seok Lee, Bo-Yun Jang, Joon-Soo Kim, Young-Soo Ahn et Churl-Hee Cho. « Microstructure Control of Columnar-Grained Silicon Substrate Solidified from Silicon Melts Using Gas Pressure ». Journal of Nanomaterials 2015 (2015) : 1–6. http://dx.doi.org/10.1155/2015/104930.

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A silicon substrate with the dimensions of 100 × 140 × 0.3 mm was grown directly from liquid silicon with gas pressure. The silicon melt in the sealed melting part was injected into the growth part at applied pressure of 780–850 Torr. The solidified silicon substrate was then transferred by the pull of the cooled dummy bar. A desirable structure with a liquid-solid interface perpendicular to the pulling direction was formed when the mold temperature in the solidification zone of the growth part was much higher than that of the dummy bar, as this technique should be able to overcome thermal loss through the molds and the limited heat flux derived from the very narrow contact area between the silicon melt and the dummy bar. In addition, because the metallic impurities and expansion of volume during solidification are preferably moved to a liquid phase, a high-quality silicon substrate, without defects such as cracks and impurities in the substrate, could be manufactured in the interface structure. The present study reports the experimental findings on a new and direct growth system for obtaining silicon substrates characterized by high quality and productivity, as a candidate for alternate routes for the fabrication of silicon substrates.

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Dhont, Blaise, Christophe Ancey et Patricio Bohorquez. « Bar dynamics and sediment transport pulses in gravel-bed channels ». E3S Web of Conferences 40 (2018) : 05047. http://dx.doi.org/10.1051/e3sconf/20184005047.

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Mountain rivers exhibit sediment transport rate fluctuations that often cover more than two orders of magnitude. Bedform migration is often cited as the key process that causes giant fluctuations in the sediment transport rate. To quantify the effect of bedform migration on transport rate, we ran laboratory experiments in a 19-m long 60-cm wide flume with well-sorted gravel bed. At the flume inlet, the water discharge and the particle flux were kept constant. Experiments were conducted over long times (typically > 500 h). Sediment transport rate was monitored at the flume outlet using accelerometers. Bed topography was scanned at high spatial resolution using a laser sheet. Water depth was measured using ultrasonic probes mounted on an automated rolling carriage. We observed that, under steady state experimental conditions, bed morphology played a key part in the generation of bedload transport fluctuations. The bars migrated downstream intermittently, producing the most important pulses. When the bar position was stable for a few hours, additional pulses resulted from sediment transfer from pool to pool, in the form of sediment waves (bedload sheets). Thus, in our experiments, alternate bars formed a two-entity system (bar + pool) with two distinctive functions: the bars contributed to fix and stabilize the bed whereas the pools were the preferential zones of short-term storage and transfer of sediment.

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Świȩch, W., R. S. Appleton, B. D. Wiemeyer et C. P. Flynn. « LEEM Investigation of Refractory Metals Grown on Insulating Substrates : Nb (110) on Sapphire $(11\bar{2}0)$ ». Surface Review and Letters 05, n^o 06 (décembre 1998) : 1221–31. http://dx.doi.org/10.1142/s0218625x98001559.

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We summarize LEEM studies of Nb (110) single crystals grown by MBE on Al 2 O 3[Formula: see text]. At temperatures between 1300 K and 1600 K the structure relaxes to create flat terraces several μm wide, and stable subgrain boundaries, by clearly visible interfacial and surface processes. The Nb surface exhibits two mirror-equivalent variants of a reconstruction, one of which prevails at low temperatures. Upon approaching Tc at ~1480 K, the two variants alternate in extended stripes along [Formula: see text], with stripe widths that decrease smoothly as T approaches Tc. Both at low T and above Tc, variants are trapped at dislocation strain fields.

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Alghamdi, Ahmad M. « Fast and Versatile Pathway in Fabrication of Polyelectrolyte Multilayer Nanofiltration Membrane with Tunable Properties ». Journal of Chemistry 2021 (10 juin 2021) : 1–6. http://dx.doi.org/10.1155/2021/9978596.

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Thin film composite nanofiltration (NF) membranes are relatively new membranes compared to other types of pressure-driven membranes. However, they attract interest from researchers due to their versatility to be used in various applications. In this work, a new class of NF membrane was successfully fabricated through spin-assisted layer-by-layer assembly by depositing alternate layers of branched polyethylenimine (PEI) and poly(sodium 4-styrenesulfonate) (PSS) on ultrafiltration polysulfone (PSF) membrane. The suitability of the fabricated membranes for removal of divalent ions was investigated. It was found that the membrane consisting of (PEI/PSS)10–0.05 M NaCl showed MgCl2 rejection rate of 93.95% and permeation flux of 0.9 L/m2·h bar during tests performed using a crossflow permeation cell at a crossflow velocity of 0.65 m/s, MgCl2 feed concentration of 6530 ppm, pressure of 10 bar, temperature of 32.5°C, and pH of 6.5. This result suggests that this new fabrication method is suitable for producing polyelectrolyte multilayered (PEM) NF membranes that exhibit comparable membrane performance to commercial ones.

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Garner, R. P., L. Terracio, T. K. Borg et J. Buggy. « Intracranial self-stimulation motivates weight-lifting exercise in rats ». Journal of Applied Physiology 71, n^o 4 (1 octobre 1991) : 1627–31. http://dx.doi.org/10.1152/jappl.1991.71.4.1627.

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The purpose of this study was to determine the feasibility of using a positive reinforcement protocol to motivate weight-lifting exercise in rats. Intracranial self-stimulation was used to induce weight-lifting exercise. Bipolar electrodes were implanted in the ventral tegmental area of rats, and the animals were trained to bar press on a continuous reinforcement schedule for electrical brain stimulation. Animals with response rates of 1,200–1,500 presses/h were then trained with a discriminative light stimulus to alternate between a normally positioned bar and an elevated bar that could be reached only by standing on the hindlimbs. The animals were fitted with a weighted jacket at a starting resistance of 5–10% of their body weight. Weight-training sessions were conducted 5 days/wk for 10 wk. Training consisted of 600 presses/session, alternating every 15 presses between the low and high bars. At the beginning of each subsequent week, the resistance was progressively increased, with some animals eventually training at resistances greater than 50% of their body weight. At the end of the training period, the rats were lifting over 550% of the starting weight. Gastrocnemius size and mean fiber diameter were increased in the weight-lifting animals. This model combines exercise with positive incentive and has the advantages of being relatively easy to implement and not producing any apparent physical or mental trauma in the animal.

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YANO, Masaaki, Yasuharu WATANABE, Satomi YAMAGUCHI et Yasuyuki HIRAI. « FLUME EXPERIMENTS AND LINEAR STABILITY ANALYSIS OF THE INFLUENCE OF NON-UNIFORM SEDIMENTS ON THE ALTERNATE BAR FORMATION ». Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 72, n^o 4 (2016) : I_775—I_780. http://dx.doi.org/10.2208/jscejhe.72.i_775.

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Asif, Farea, Muhammad Haris Hamayun, Murid Hussain, Arif Hussain, Ibrahim M. Maafa et Young-Kwon Park. « Performance Analysis of the Perhydro-Dibenzyl-Toluene Dehydrogenation System—A Simulation Study ». Sustainability 13, n^o 11 (7 juin 2021) : 6490. http://dx.doi.org/10.3390/su13116490.

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The depletion of conventional energy resources has drawn the world’s attention towards the use of alternate energy resources, which are not only efficient but sustainable as well. For this purpose, hydrogen is considered the fuel of the future. Liquid organic hydrogen carriers (LOHCs) have proved themselves as a potential option for the release and storage of hydrogen. The present study is aimed to analyze the performance of the perhydro-dibenzyl-toluene (PDBT) dehydrogenation system, for the release of hydrogen, under various operational conditions, i.e., temperature range of 270–320 °C, pressure range of 1–3 bar, and various platinum/palladium-based catalysts. For the operational system, the optimum operating conditions selected are 320 °C and 2 bar, and 2 wt. % Pt/Al2O3 as a suitable catalyst. The configuration is analyzed based on exergy analysis i.e., % exergy efficiency, and exergy destruction rate (kW), and two optimization strategies are developed using principles of process integration. Based on exergy analysis, strategy # 2, where the product’s heat is utilized to preheat the feed, and utilities consumption is minimized, is selected as the most suitable option for the dehydrogenation system. The process is simulated and optimized using Aspen HYSYS® V10.

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Oerlemans, Stan C. M., Wiebe Nijland, Ashley N. Ellenson et Timothy D. Price. « Image-Based Classification of Double-Barred Beach States Using a Convolutional Neural Network and Transfer Learning ». Remote Sensing 14, n^o 19 (20 septembre 2022) : 4686. http://dx.doi.org/10.3390/rs14194686.

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Nearshore sandbars characterize many sandy coasts, and unravelling their dynamics is crucial to understanding nearshore sediment pathways. Sandbar morphologies exhibit complex patterns that can be classified into distinct states. The tremendous progress in data-driven learning in image recognition has recently led to the first automated classification of single-barred beach states from Argus imagery using a Convolutional Neural Network (CNN). Herein, we extend this method for the classification of beach states in a double-barred system. We used transfer learning to fine-tune the pre-trained network of ResNet50. Our data consisted of labelled single-bar time-averaged images from the beaches of Narrabeen (Australia) and Duck (US), complemented by 9+ years of daily averaged low-tide images of the double-barred beach of the Gold Coast (Australia). We assessed seven different CNNs, of which each model was tested on the test data from the location where its training data came from, the self-tests, and on the test data of alternate, unseen locations, the transfer-tests. When the model trained on the single-barred data of both Duck and Narrabeen was tested on unseen data of the double-barred Gold Coast, we achieved relatively low performances as measured by F1 scores. In contrast, models trained with only the double-barred beach data showed comparable skill in the self-tests with that of the single-barred models. We incrementally added data with labels from the inner or outer bar of the Gold Coast to the training data from both single-barred beaches, and trained models with both single- and double-barred data. The tests with these models showed that which bar the labels used for training the model mattered. The training with the outer bar labels led to overall higher performances, except at the inner bar. Furthermore, only 10% of additional data with the outer bar labels was needed for reasonable transferability, compared to the 20% of additional data needed with the inner bar labels. Additionally, when trained with data from multiple locations, more data from a new location did not always positively affect the model’s performance on other locations. However, the larger diversity of images coming from more locations allowed the transferability of the model to the locations from where new training data were added.

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Ashmore, Peter E. « How do gravel-bed rivers braid ? » Canadian Journal of Earth Sciences 28, n^o 3 (1 mars 1991) : 326–41. http://dx.doi.org/10.1139/e91-030.

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Sedimentary processes and bed forms leading to the onset of braiding were observed in small-scale hydraulic models of gravel-bed streams. The laboratory streams had a variety of combinations of (constant) discharge and slope but identical bed-material particle-size distributions. From initially straight channels, braiding occurred by four different processes: deposition and accumulation of a central bar, chute cutoff of point bars, conversion of single transverse unit bars to mid-channel braid bars, and dissection of multiple bars. In these experiments the chute cutoff mechanism was the most common, but the predominant braiding mechanism depends upon sediment mobility (excess bed shear stress) and the bed-form regime. At very low excess bed shear stress the central bar process dominates, but at higher excess bed shear stress slip-face unit bars are more common, bed scour at confluences is more pronounced, and propogation of alternate convergence (scour) and divergence (deposition) is more likely; thus chute cutoffs and bar conversion dominate. The multiple bar mechanism is restricted to channels with very high width/depth ratio. All of these processes, along with avulsion, are significant for maintenance of an established braided channel.The direct physical sedimentary cause of primary braiding is essentially the same in all these processes: local aggradation (often by stalling of bed-load sheets) and loss of competence in a lateral flow expansion. The chute cutoff process occurs in a morphologically distinctive setting and may be aided by other factors, but it is usually triggered by the local thalweg shoaling that is the fundamental physical mechanism causing the onset of braiding by the other processes. Local short-term pulses in bed-load supply are often the trigger for the initiation and maintenance of braiding, regardless of the exact braiding process.

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NIHEI, Tatsuya, Hirotomo IHARA et Hiroshi SEKI. « CORROSION MECHANISM OF REINFORCING BAR EMBEDDED IN CONCRETE DAMAGED DUE TO NEUTRALIZATION AND UNDER ALTERNATE DRYING AND WETTING CONDITIONS ». Doboku Gakkai Ronbunshu, n^o 753 (2004) : 65–79. http://dx.doi.org/10.2208/jscej.2004.753_65.

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Wang, D., et M. Vidyasagar. « Control of a Class of Manipulators With a Single Flexible Link : Part I—Feedback Linearization ». Journal of Dynamic Systems, Measurement, and Control 113, n^o 4 (1 décembre 1991) : 655–61. http://dx.doi.org/10.1115/1.2896471.

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The subject of this paper is the feedback linearization of the input-output and input-state equations for a class of multi-link, three degrees-of-freedom manipulators with the last link flexible. This class includes the 5-bar-linkage and the elbow manipulator. It is shown that the input-output equations are only feedback linearizable if the output variables are chosen appropriately. However, the nonlinear dynamics made unobservable by this feedback are not asymptotically stable which is a severe drawback. It is then shown that the input-state equations are not feedback linearizable. These results indicate that feedback linearization techniques are not appropriate for this class of manipulators. Thus, alternate methodologies should be explored. That issue is tackled in Part II.

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