Articles de revues : « Joint power »

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TANIGUCHI, Katsunori. « PCC : IEEJ/IEEE Joint IAS Power Conversion Conference ». Journal of the Institute of Electrical Engineers of Japan 136, n^o 4 (2016) : 214–16. http://dx.doi.org/10.1541/ieejjournal.136.214.

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Wang, Bo, Kailin Pan, Yubing Gong, Yuhong Long et Kai Shi. « Effect of ultrasonic power on wettability, porosity and mechanical properties of ultrasonic-aided laser reflow soldering ». International Journal of Modern Physics B 35, n^o 05 (2 février 2021) : 2150063. http://dx.doi.org/10.1142/s0217979221500636.

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Wettability, porosity and mechanical properties of ultrasonic-aided laser reflow soldering lead-free solder Sn-3.0Ag-0.5Cu (SAC305) on Cu pad have been investigated at ultrasonic vibration (USV) of different power. The parameters of laser reflow soldering are determined by the wetting experiment, and the effects of different ultrasonic powers on the performance of the solder joint are studied. Results showed that USV can improve wettability without keyholes on top of the solder joint, and the contact angle between the solder joint and the substrate decreases first and then increases as the ultrasonic power increases. The cavitation effect caused by USV effectively reduces the porosity of the solder joints. When the ultrasonic power is 225 W, the porosity of the solder joint is reduced from the initial 13.2% to 5.2%. Through X-ray Diffraction (XRD) analysis of the solder joint matrix, all solder joints have diffraction peaks of [Formula: see text]-Sn, Cu6Sn5 and Ag3Sn, and the solder joints show higher diffraction peak intensity with USV treated. Furthermore, the solder joints prepared by ultrasonic-aided laser reflow soldering show better shear strength compared with laser reflow soldering.

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Zhao, Ying Na, Jia Chen Liu, Hai Xu et Wen Li Zhang. « Microwave Joining 95-Al₂O₃ Ceramics Used Al-Si Alloy as Interlayer ». Advanced Materials Research 291-294 (juillet 2011) : 1313–16. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.1313.

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Absorber-microwave material Al-Si alloy powder was used as interlayer to join the 95-Al2O3ceramics. The behaviors curves of time-temperature for Al-Si alloy interlayer and 95-Al2O3ceramics at different microwave power were researched. The interlayer morphology of the joints region was characterized by SEM and the element and phase components were analyzed by EDX and XRD. The results indicated that the loact heating around 95-Al2O3ceramics could be achieved by microwave sintering. The joint interfaces of Al-Si/95-Al2O3formed at microwave 2KW/20min→0KW and the joint mechanism of 95-Al2O3ceramics was transient liquid phase diffusion bond.

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He, Dajiang, Bohan Liu, Zhenwu Wang, You Shu et Minghui Liu. « Study on Fault Optimization of Intermediate Joint of Power Cable ». Journal of Physics : Conference Series 2260, n^o 1 (1 avril 2022) : 012025. http://dx.doi.org/10.1088/1742-6596/2260/1/012025.

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Abstract Cable joints are often prone to failure due to loose contact, small contact area and increased contact resistance, resulting in obvious heating. In the existing cable emergency repair work, the cable joints of the original section of the cable and the access end are made on site. Due to the long production time, the emergency repair speed is reduced. Therefore, this paper studies the connection mode of the new cable joint to make the contact between conductors more sufficient and the contact resistance smaller, and designs a scheme of three-phase cable plug-in intermediate joint with high safety and simple installation; at the position of cable joint, three kinds of flexible conductive polymer materials suitable for joint connection are proposed to be used at the contact gap between conductor and conductor, conductor and conductor sleeve, so as to make close contact, reduce contact resistance and further reduce the incidence of cable joint failure.

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McDaniel, John, N. Scott Behjani, Steven J. Elmer, Nicholas A. T. Brown et James C. Martin. « Joint-Specific Power-Pedaling Rate Relationships During Maximal Cycling ». Journal of Applied Biomechanics 30, n^o 3 (juin 2014) : 423–30. http://dx.doi.org/10.1123/jab.2013-0246.

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Previous authors have reported power-pedaling rate relationships for maximal cycling. However, the joint-specific power-pedaling rate relationships that contribute to pedal power have not been reported. We determined absolute and relative contributions of joint-specific powers to pedal power across a range of pedaling rates during maximal cycling. Ten cyclists performed maximal 3 s cycling trials at 60, 90, 120, 150, and 180 rpm. Joint-specific powers were averaged over complete pedal cycles, and extension and flexion actions. Effects of pedaling rate on relative joint-specific power, velocity, and excursion were assessed with regression analyses and repeated-measures ANOVA. Relative ankle plantar flexion power (25 to 8%;P= .01;R2= .90) decreased with increasing pedaling rate, whereas relative hip extension power (41 to 59%;P< .01;R2= .92) and knee flexion power (34 to 49%;P< .01;R2= .94) increased with increasing pedaling rate. Knee extension powers did not differ across pedaling rates. Ankle joint angular excursion decreased with increasing pedaling rate (48 to 20 deg) whereas hip joint excursion increased (42 to 48 deg). These results demonstrate that the often-reported quadratic power-pedaling rate relationship arises from combined effects of dissimilar joint-specific power-pedaling rate relationships. These dissimilar relationships are likely influenced by musculoskeletal constraints (ie, muscle architecture, morphology) and/or motor control strategies.

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Dobney, J. A., M. R. Owen, G. R. Colborne et N. J. Burton. « Joint angle, moment and power compensations in dogs with fragmented medial coronoid process ». Veterinary and Comparative Orthopaedics and Traumatology 21, n^o 02 (2008) : 110–18. http://dx.doi.org/10.3415/vcot-07-04-0038.

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SummaryFragmented medial coronoid process (FMCP) is the most common cause of forelimb lameness in juvenile medium and large breed dogs; however methods of assessing the disruption to their gait remain subjective. The purpose of this study was to objectively quantify the mechanical disruptions to gait in dogs with arthroscopically confirmed unilateral FMCP. Seven dogs underwent full inverse dynamic analysis at the time of diagnosis. Kinematic and force data were collected from both forelimbs at trot. Stance phase joint angles, net joint moments and net joint powers were calculated using custom software. There were gross differences in kinetic and kinematic patterns between FMCP affected and compensating forelimbs. Stance time was 0.24 sec on the lame side and 0.26 sec on the compensating side. The shoulder and the elbow were more flexed at ground contact, and elbow, carpal and MCP joints had smaller ranges of motion on the lame side. Net joint moments were significantly reduced (P<0.05) in the elbow, carpal and MCP joints of the FMCP affected limb. Net joint powers were likewise significantly smaller (P<0.05). However, the overall moment and power patterns persisted. Total limb support moment was significantly smaller on the affected side (P<0.05). Total limb power was significantly reduced on the affected side (P<0.05) being most affected in its propulsive phase in the second half of stance. Inverse dynamic analysis of this clinical condition is an objective means by which to assess the mechanical disruption to gait.

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Lyons, Samuel M., Jeffery J. Morgan, Salinda K. Chan et Emily A. Kraus. « Altered Joint Powers During Running After Tibial Bone Stress Injury ». Orthopaedic Journal of Sports Medicine 10, n^o 5_suppl2 (1 mai 2022) : 2325967121S0049. http://dx.doi.org/10.1177/2325967121s00493.

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Background: Tibial bone stress injuries (tib-BSI) are common in adolescent runners. Previous research has examined running mechanics as possible risk factors for tib-BSI’s and implications have been observed for both kinematic and kinetic measures. Combining these measures to examine power absorption and production of the lower extremity can provide context on mechanical differences in individuals with a history of tib-BSI. Hypothesis/Purpose: The purpose of this study was to examine total limb power and percent joint contribution in healthy adolescent runners compared to peers with a history of tib-BSI. It was hypothesized that runners with a history of tib-BSI would have a greater contribution of power production and absorption at the ankle, and less at the hip and knee joints, with no difference in total power. Methods: Twenty-six runners were divided into groups: history of tib-BSI (n=14; male=10, female=4; age=16±2) and healthy controls (n=12; male=5, female=7; age=18±7). Data were collected using 3D motion capture with embedded force plates during overground running at self-selected pace. Total limb power and percent joint contribution were calculated from joint work. Positive and negative joint work was summed from the integrations of the joint power-time curve in each plane. Joint work was divided by step-time to obtain total joint power. Joint powers for the hip, knee, and ankle were summed to determine total limb power and percentage of limb power was calculated for each joint. Variables were grouped by control limb (CON), uninvolved limb (UNI), and involved limb (BSI). Both limbs in the healthy controls were averaged to generate the CON group. A one-way ANOVA was used to compare the variables of limb and joint power. Results: There were no significant differences between BSI and UNI limbs for any variables measured. The CON group exhibited significantly greater hip negative power compared to the BSI group (p=0.047), and significantly less ankle negative power compared to the BSI (p=0.001) and UNI groups (p=0.002). Despite a significant difference in total positive power between groups (p=0.04), there were no differences in joint positive power. Variables are presented in Table 1. Conclusion: This study is preliminary evidence that adolescent runners with a history of tib-BSI can present with adaptations in running mechanics that are not limited to the injured leg. Negative power may be more sensitive to change with the ankle increasing its contribution, comparatively. Clinicians and researchers should be aware of this adaptation after injury as it may influence treatment.

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Višniakov, Nikolaj, Jelena Škamat, Olegas Černašėjus et Artūras Kilikevičius. « Flash Welding of Microcomposite Wires for Pulsed Power Applications ». Metals 10, n^o 8 (5 août 2020) : 1053. http://dx.doi.org/10.3390/met10081053.

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This paper presents the experimental results of Cu-Nb wire joining upon applying flash welding technology. The present research is aimed at investigating the structure, electrical and mechanical properties of butt welding joints of Cu-Nb conductors, usable for coils of pulsed magnetic systems. The butt joint structure was found to be free of welding defects. The structure of the butt welded joint provides an insignificant increase in electrical resistance and sufficient ultimate strength and plasticity of the joint. The tensile strength of the welded sample reaches 630 MPa.

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Topete, Martha, Nathan Betancourt et Flore Bridoux. « Position Power and Joint Creativity ». Academy of Management Proceedings 2021, n^o 1 (août 2021) : 10023. http://dx.doi.org/10.5465/ambpp.2021.10023abstract.

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Reuvid, J. « Power to the joint venture ». Engineering & ; Technology 3, n^o 3 (23 février 2008) : 82–83. http://dx.doi.org/10.1049/et:20080321.

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Suzumori, Koichi, Masanori Takata et Shuichi Wakimoto. « Development of Joints for Power Microrobot for Searching inside Debris ». Journal of Robotics and Mechatronics 15, n^o 5 (20 octobre 2003) : 555–60. http://dx.doi.org/10.20965/jrm.2003.p0555.

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Searching for victims in narrow gaps and shoring up pieces of debris to secure space are tasks encountered in disaster rescue operations. The authors have developed high-strength robot joints for microrobots to be used in such situations. The joints developed are of three types - swivel joint, extension joint, and strut joint - all having an outer diameter of 60mm and driven by a 21MPa hydraulic system. This paper presents the system configuration of a power microrobot for traveling and searching inside debris, then describes the mechanisms and controls of the three developed joints. This study thereby demonstrates the possibility of realizing a microrobot capable of maneuvering within narrow gaps and shoring debris to secure space. The microrobot weighs approximately 25 or 35kg (including the hydraulic unit), is driven by a 100V power supply, with 300W power consumption, and has an outer diameter of 60mm and length of about 1m.

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Li, Guoyu, Rui Zhang, Dianlei Han, Hao Pang, Guolong Yu, Qingqiu Cao, Chen Wang et al. « Forelimb joints contribute to locomotor performance in reindeer (Rangifer tarandus) by maintaining stability and storing energy ». PeerJ 8 (11 novembre 2020) : e10278. http://dx.doi.org/10.7717/peerj.10278.

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Reindeer (Rangifer tarandus) have lengthy seasonal migrations on land and their feet possess excellent locomotor characteristics that can adapt to complex terrains. In this study, the kinematics and vertical ground reaction force (GRF) of reindeer forelimb joints (interphalangeal joint b, metacarpophalangeal joint c, and wrist joint d) under walk, trot 1, and trot 2 were measured using a motion tracking system and Footscan pressure plates. Significant differences among different locomotor activities were observed in the joint angles, but not in changes of the joint angles (αb, αc, αd) during the stance phase. Peak vertical GRF increased as locomotor speed increased. Net joint moment, power, and work at the forelimb joints were calculated via inverse dynamics. The peak joint moment and net joint power related to the vertical GRF increased as locomotor speed increased. The feet absorbed and generated more energy at the joints. During different locomotor activities, the contribution of work of the forelimbs changed with both gait and speed. In the stance phase, the metacarpophalangeal joint absorbed more energy than the other two joints while trotting and thus performed better in elastic energy storage. The joint angles changed very little (∼5°) from 0 to 75% of the stance phase, which reflected the stability of reindeer wrist joints. Compared to typical ungulates, reindeer toe joints are more stable and the stability and energy storage of forelimb joints contribute to locomotor performance in reindeer.

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Pei, Qiang, Cong Wu, Zhi Cheng, Yu Ding et Hang Guo. « The Seismic Performance of New Self-Centering Beam-Column Joints of Conventional Island Main Buildings in Nuclear Power Plants ». Materials 15, n^o 5 (24 février 2022) : 1704. http://dx.doi.org/10.3390/ma15051704.

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In order to improve the deformation energy consumption and self-centering ability of reinforced concrete (RC) frame beam-column joints for main buildings of conventional islands in nuclear power plants, a new type of self-centering joint equipped with super-elastic shape memory alloy (SMA) bars and a steel plate as kernel components in the core area of the joint is proposed in this study. Four 1/5-scale frame joints were designed and manufactured, including two contrast joints (a normal reinforced concrete joint and a concrete joint that replaces steel bars with SMA bars) and two new model joints with different SMA reinforcement ratios. Subsequently, the residual deformation, energy dissipation capacity, stiffness degradation and self-centering performance of the novel frame joints were studied through a low-frequency cyclic loading test. Finally, based on the OpenSees finite element software platform, an effective numerical model of the new joint was established and verified. On this basis, varying two main parameters, the SMA reinforcement ratio and the axial compression ratio, a simulation was systematically conducted to demonstrate the effectiveness of the proposed joint in seismic performance. The results show that replacing ordinary steel bars in the beam with SMA bars not only greatly reduces the bearing capacity and stiffness of the joint, but also makes the failure mode of the joint brittle. The construction of a new type of joint with consideration of the SMA reinforcement and the steel plate can improve the bearing capacity, delay the stiffness degradation and improve the ductility and self-centering capability of the joints. Within a certain range, increasing the ratio of the SMA bars can further improve the ultimate bearing capacity and energy dissipation capacity of the new joint. Increasing or decreasing the axial compression ratio of column ends has little effect on the overall seismic performance of new joints.

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Wang, Yan Ling, et Xiao Feng Zhou. « Master-Slave Joint Power Flow with Wind Power Generators ». Applied Mechanics and Materials 668-669 (octobre 2014) : 745–48. http://dx.doi.org/10.4028/www.scientific.net/amm.668-669.745.

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First based on the analysis of dynamic characteristics of wind power generators, the uniform extended flow model for transmission-distribution joint with wind power generators is derived. The master-slave decomposition and coordination solving methods is proposed. Master-slave system joint calculation, considering the affect between each other, realized the joint integration calculation of power system and improved the verisimilitude of results. And, the dynamic characteristics of dynamic element of the master-slave system are considered, and it makes the results more practical. Finally, through 94-node example system analysis, the effectiveness and necessity of the proposed model and method is verified.

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Akram, Shazad, Johan Sidén et Kent Bertilsson. « Battery Powered Inductive Welding System for Electrofusion Joints in Optical Fiber Microducts ». Electronics 10, n^o 6 (21 mars 2021) : 743. http://dx.doi.org/10.3390/electronics10060743.

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Optical fiber microducts are joined together by mechanical joints. These mechanical joints are bulky, require more space per joint, and are prone to air pressure leakage and water seepage during service. A battery powered electrofusion welding system with a resistive-type joint has been recently developed to replace mechanical joints. These resistive-type electrofusion joints require physical connectors for power input. Due to a different installation environment, the power input connectors of resistive optical fiber microduct joints may corrode over time. This corrosion of connectors will eventually cause water seepage or air pressure leakage in the long run. Moreover, due to connector corrosion, resistive-type optical fiber microduct joints cannot be re-heated in future if the need arises. In this study, an inductively coupled electrofusion-type joint was proposed and investigated. This inductive-type electrofusion joint is not prone to long-term corrosion risk, due to the absence of power connectors. Inductive-type electrofusion joints can be re-heated again for resealing or removal in the long run, as no metal part is exposed to the environment. The battery powered inductive welding system can be easily powered with a 38 volts 160 watt-hour battery. The inductive-type electrofusion joint was welded within one second, and passed a 300-newton pull strength test and a 10-bar air pressure leakage test. It was demonstrated that the power input requirement for inductive electrofusion joints is 64% higher than that of resistive electrofusion joints. However, these inductive joints are relatively easy to manufacture, inexpensive, have no air leakage, and no water seepage risk in highly corrosive environments.

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Costes, Antony, David Villeger, Pierre Moretto et Bruno Watier. « Transferability between Isolated Joint Torques and a Maximum Polyarticular Task : A Preliminary Study ». Journal of Human Kinetics 50, n^o 1 (1 avril 2016) : 5–14. http://dx.doi.org/10.1515/hukin-2015-0136.

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AbstractThe aims of this study were to determine if isolated maximum joint torques and joint torques during a maximum polyarticular task (i.e. cycling at maximum power) are correlated despite joint angle and velocity discrepancies, and to assess if an isolated joint-specific torque production capability at slow angular velocity is related to cycling power. Nine cyclists completed two different evaluations of their lower limb maximum joint torques. Maximum Isolated Torques were assessed on isolated joint movements using an isokinetic ergometer and Maximum Pedalling Torques were calculated at the ankle, knee and hip for flexion and extension by inverse dynamics during cycling at maximum power. A correlation analysis was made between Maximum Isolated Torques and respective Maximum Pedalling Torques [3 joints x (flexion + extension)], showing no significant relationship. Only one significant relationship was found between cycling maximum power and knee extension Maximum Isolated Torque (r=0.68, p<0.05). Lack of correlations between isolated joint torques measured at slow angular velocity and the same joint torques involved in a polyarticular task shows that transfers between both are not direct due to differences in joint angular velocities and in mono-articular versus poly articular joint torque production capabilities. However, this study confirms that maximum power in cycling is correlated with slow angular velocity mono-articular maximum knee extension torque.

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Ku, Meng-Lin, Yi Han, Beibei Wang et K. J. Ray Liu. « Joint Power Waveforming and Beamforming for Wireless Power Transfer ». IEEE Transactions on Signal Processing 65, n^o 24 (15 décembre 2017) : 6409–22. http://dx.doi.org/10.1109/tsp.2017.2755582.

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Leong, Chee-Hoi, Steven J. Elmer et James C. Martin. « Noncircular Chainrings Do Not Influence Maximum Cycling Power ». Journal of Applied Biomechanics 33, n^o 6 (1 décembre 2017) : 410–18. http://dx.doi.org/10.1123/jab.2017-0035.

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Noncircular chainrings could increase cycling power by prolonging the powerful leg extension/flexion phases, and curtailing the low-power transition phases. We compared maximal cycling power-pedaling rate relationships, and joint-specific kinematics and powers across 3 chainring eccentricities (CON = 1.0; LOWecc = 1.13; HIGHecc = 1.24). Part I: Thirteen cyclists performed maximal inertial-load cycling under 3 chainring conditions. Maximum cycling power and optimal pedaling rate were determined. Part II: Ten cyclists performed maximal isokinetic cycling (120 rpm) under the same 3 chainring conditions. Pedal and joint-specific powers were determined using pedal forces and limb kinematics. Neither maximal cycling power nor optimal pedaling rate differed across chainring conditions (all p > .05). Peak ankle angular velocity for HIGHecc was less than CON (p < .05), while knee and hip angular velocities were unaffected. Self-selected ankle joint-center trajectory was more eccentric than HIGHecc with an opposite orientation that increased velocity during extension/flexion and reduced velocity during transitions. Joint-specific powers did not differ across chainring conditions, with a small increase in power absorbed during ankle dorsiflexion with HIGHecc. Multiple degrees of freedom in the leg, crank, and pedal system allowed cyclists to manipulate ankle angular velocity to maintain their preferred knee and hip actions, suggesting maximizing extension/flexion and minimizing transition phases may be counterproductive for maximal power.

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Kumar, V. Vignesh, et K. Giridhar. « Power Efficient Communication for Joint Detection Receivers in Rician Channels ». International Journal of Interdisciplinary Telecommunications and Networking 8, n^o 1 (janvier 2016) : 1–11. http://dx.doi.org/10.4018/ijitn.2016010101.

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In a multipoint to point link, where multiple streams from geographically separated points co-existing in time and frequency are jointly detected, the relative powers at which the signals are received play an important role in deciding the sum rate. Unlike Rayleigh fading, where decreasing the power of any of the streams will result only in decrease in the sum rate, Rician fading exhibits an interesting behavior where one can actually improve the sum rate by decreasing the power of one or more of the transmitted streams. This gives rise to the possibility of power efficient communications under Rician channel conditions. In this paper, the authors discuss a power control scheme where the receiver, based on the present received powers and k-factor, feeds back the optimal powers to be transmitted so that the total transmitted power is minimized without any loss in the sum rate. It can be shown that by employing such a power control scheme, considerable amount of power can be saved on the transmit side, paving way to greener communications, for LoS or near LoS links.

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Bezodis, Neil E., Aki I. T. Salo et Grant Trewartha. « Modeling the Stance Leg in Two-Dimensional Analyses of Sprinting : Inclusion of the MTP Joint Affects Joint Kinetics ». Journal of Applied Biomechanics 28, n^o 2 (mai 2012) : 222–27. http://dx.doi.org/10.1123/jab.28.2.222.

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Two-dimensional analyses of sprint kinetics are commonly undertaken but often ignore the metatarsal-phalangeal (MTP) joint and model the foot as a single segment. The aim of this study was to quantify the role of the MTP joint in the early acceleration phase of a sprint and to investigate the effect of ignoring the MTP joint on the calculated joint kinetics at the other stance leg joints. High-speed video and force platform data were collected from four to five trials for each of three international athletes. Resultant joint moments, powers, and net work at the stance leg joints during the first stance phase after block clearance were calculated using three different foot models. Considerable MTP joint range of motion (>30°) and a peak net MTP plantar flexor moment of magnitude similar to the knee joint were observed, thus highlighting the need to include this joint for a more complete picture of the lower limb energetics during early acceleration. Inclusion of the MTP joint had minimal effect on the calculated joint moments, but some of the calculated joint power and work values were significantly (P < .05) and meaningfully affected, particularly at the ankle. The choice of foot model is therefore an important consideration when investigating specific aspects of sprinting technique.

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Filer, Andrew, Paola de Pablo, Gina Allen, Peter Nightingale, Alison Jordan, Paresh Jobanputra, Simon Bowman, Christopher D. Buckley et Karim Raza. « Utility of ultrasound joint counts in the prediction of rheumatoid arthritis in patients with very early synovitis ». Annals of the Rheumatic Diseases 70, n^o 3 (29 novembre 2010) : 500–507. http://dx.doi.org/10.1136/ard.2010.131573.

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ObjectivesEarly therapy improves outcomes in rheumatoid arthritis (RA). It is therefore important to improve predictive algorithms for RA in early disease. This study evaluated musculoskeletal ultrasound, a sensitive tool for the detection of synovitis and erosions, as a predictor of outcome in very early synovitis.Methods58 patients with clinically apparent synovitis of at least one joint and symptom duration of ≤3 months underwent clinical, laboratory, radiographic and 38 joint ultrasound assessments and were followed prospectively for 18 months, determining outcome by 1987 American College of Rheumatology (ACR) and 2010 ACR/European League Against Rheumatism criteria. Sensitivity and specificity for 1987 RA criteria were determined for ultrasound variables and logistic regression models were then fitted to evaluate predictive ability over and above the Leiden rule.Results16 patients resolved, 13 developed non-RA persistent disease and 29 developed RA by 1987 criteria. Ultrasound demonstrated subclinical wrist, elbow, knee, ankle and metatarsophalangeal joint involvement in patients developing RA. Large joint and proximal interphalangeal joint ultrasound variables had poor predictive ability, whereas ultrasound erosions lacked specificity. Regression analysis demonstrated that greyscale wrist and metacarpophalangeal joint involvement, and power Doppler involvement of metatarsophalangeal joints provided independently predictive data. Global ultrasound counts were inferior to minimal power Doppler counts, which significantly improved area under the curve values from 0.905 to 0.962 combined with the Leiden rule.ConclusionIn a longitudinal study, extended ultrasound joint evaluation significantly increased detection of joint involvement in all regions and outcome groups. Greyscale and power Doppler scanning of metacarpophalangeal joints, wrists and metatarsophalangeal joints provides the optimum minimal ultrasound data to improve on clinical predictive models for RA.

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Deschamps, Kevin, Giovanni Matricali, Maarten Eerdekens, Sander Wuite, Alberto Leardini et Filip Staes. « The Receptive and Propulsive Behavior of Human Foot Joints During Running With Different Striking Strategies ». Journal of Applied Biomechanics 35, n^o 5 (1 octobre 2019) : 336–43. http://dx.doi.org/10.1123/jab.2018-0442.

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Foot structure and kinematics have long been considered as risk factors for foot and lower-limb running injuries. The authors aimed at investigating foot joint kinetics to unravel their receptive and propulsive characteristics while running barefoot, both with rearfoot and with midfoot striking strategies. Power absorption and generation occurring at different joints of the foot in 6 asymptomatic adults were calculated using both a 3-segment and a 4-segment kinetic model. An inverse dynamic approach was used to quantify mechanical power. Major power absorption and generation characteristics were observed at the ankle joint complex as well as at the Chopart joint in both the rearfoot and the midfoot striking strategies. The power at the Lisfranc joint, quantified by the 4-segment kinetic model, was predominantly generated in both strategies, and at the toes, it was absorbed. The overall results show a large variability in the receptive and propulsive characteristics among the analyzed joints in both striking strategies. The present study may provide novel insight for clinical decision making to address foot and lower-limb injuries and to guide athletes in the adoption of different striking strategies during running.

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Chang, Dillon E., Lois P. Buschbacher et Richard F. Edlich. « Limited joint mobility in power lifters ». American Journal of Sports Medicine 16, n^o 3 (mai 1988) : 280–84. http://dx.doi.org/10.1177/036354658801600315.

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Caprice, Stéphane, et Patrick Rey. « Buyer Power from Joint Listing Decision ». Economic Journal 125, n^o 589 (22 septembre 2015) : 1677–704. http://dx.doi.org/10.1111/ecoj.12241.

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Papagiannaki, Konstantina (Dina). « The power of joint multiuser beamforming ». Communications of the ACM 57, n^o 7 (juillet 2014) : 96. http://dx.doi.org/10.1145/2618411.

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Pettitt, R. W., B. M. Wagner et J. C. Martin. « AVERAGE JOINT POWER DURING MAXIMAL CYCLING ». Medicine & ; Science in Sports & ; Exercise 34, n^o 5 (mai 2002) : S173. http://dx.doi.org/10.1097/00005768-200205001-00968.

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Zhang, Cheng, Deyan Lin et S. Y. Ron Hui. « Ball-Joint Wireless Power Transfer Systems ». IEEE Transactions on Power Electronics 33, n^o 1 (janvier 2018) : 65–72. http://dx.doi.org/10.1109/tpel.2017.2700898.

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Choi, Jinho. « Massive MIMO With Joint Power Control ». IEEE Wireless Communications Letters 3, n^o 4 (août 2014) : 329–32. http://dx.doi.org/10.1109/lwc.2014.2315039.

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Wannop, John, Nicole Schrier, Marie-Louise Wolter, Ryan Madden, Zach Barrons et Darren Stefanyshyn. « Changes in Joint Power and Energetics during a Sport-Specific Jumping Fatigue Protocol ». Applied Sciences 13, n^o 3 (17 janvier 2023) : 1231. http://dx.doi.org/10.3390/app13031231.

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Kinematic and kinetic changes in the lower extremities occur as an athlete becomes fatigued during vertical jumping; however, the specifics of these changes are not well-understood. Therefore, the purpose of this study was to quantify the influence of a sport-specific, vertical jumping fatigue protocol on the biomechanics of the ankle, knee, and hip joint. Twenty male varsity athletes performed repetitive standing countermovement squat jumps every 20 s until fatigued (vertical jump and reach height decreased to 88% of their maximum height for three consecutive jumps). The kinematics and kinetics of their lower extremities (ankle, knee, and hip) were quantified, and the ankle, knee, and hip joint’s moments, angular velocity, and joint power were compared. The participants performed an average of 175 jumps before they were classified as being fatigued. When they became fatigued, the peak power of the ankle and hip joints were substantially reduced due to a decrease in the angular velocity at both joints. Ankle and hip joint moments were unchanged. Peak power at the knee joint was also unchanged over the course of the jumping protocol. To maintain vertical jumping performance over the course of a game or to delay the influence of fatigue, training should be targeted at maintaining the angular velocity of the ankle and hip joints.

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Laskari, Katerina, George Pentazos, Despina Pitsilka, John Raftakis, George Konstantonis, Konstantinos Toutouzas, Elias Siores, Maria Tektonidou et Petros P. Sfikakis. « Joint microwave radiometry for inflammatory arthritis assessment ». Rheumatology 59, n^o 4 (5 septembre 2019) : 839–44. http://dx.doi.org/10.1093/rheumatology/kez373.

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Abstract Objectives Increased in-depth joint temperature measured by the rapid, easy-to-perform microwave radiometry (MWR) method may reflect inflammation, even in the absence of clinical signs. We hypothesized that MWR is useful for RA and spondyloarthritis patients’ assessment. Methods Clinical examination, joint ultrasound and/or MRI and MWR were performed in two independent patient–control cohorts (n = 243). Results Among single RA joints MWR performed best in the knee using ultrasound as reference, with 75% sensitivity–73% specificity for grey-scale synovitis score ⩾2, and 80% sensitivity–82% specificity for power Doppler positivity. A stronger agreement was evident between increased knee relative temperature (Δt) and power Doppler positivity (82%) than with clinical examination (76%). In a different patient cohort with painful knees, a knee Δt ⩽0.2 predicted power Doppler positivity with 100% positive and negative predictive values. A thermo-score summing 10 Δt values of three large and seven small RA joints (elbow, knee, ankle, wrist, four hand and two foot joints of the clinically dominant arm or hand and leg or foot) correlated with ultrasound scores of synovitis/tenosynovitis (all P < 0.001) and the 28-joint Disease Activity Score (DAS28) (P = 0.004). The agreement of the thermo-score with ultrasound-defined joint inflammation (82%) was stronger than with DAS28 (64%). The thermo-score improved significantly after 90 days of treatment in patients with active RA at baseline (P = 0.004). Using MRI as reference, Δt of sacroiliac joints could discriminate between spondyloarthritis patients with or without sacroiliitis with 78% sensitivity–74% specificity. Conclusion In-depth increased MWR-derived joint temperature reflects both subclinical and clinically overt inflammation and may serve as a biomarker in arthritis.

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Kulmala, Juha-Pekka, Marko T. Korhonen, Sami Kuitunen, Harri Suominen, Ari Heinonen, Aki Mikkola et Janne Avela. « Which muscles compromise human locomotor performance with age ? » Journal of The Royal Society Interface 11, n^o 100 (6 novembre 2014) : 20140858. http://dx.doi.org/10.1098/rsif.2014.0858.

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Ageing leads to a progressive decline in human locomotor performance. However, it is not known whether this decline results from reduced joint moment and power generation of all lower limb muscle groups or just some of them. To further our understanding of age-related locomotor decline, we compare the amounts of joint moments and powers generated by lower limb muscles during walking (self-selected), running (4 m s −1 ) and sprinting (maximal speed) among young, middle-aged and old adults. We find that age-related deficit in ankle plantarflexor moment and power generation becomes more severe as locomotion change from walking to running to sprinting. As a result, old adults generate more power at the knee and hip extensors than their younger counterparts when walking and running at the same speed. During maximal sprinting, young adults with faster top speeds demonstrate greater moments and powers from the ankle and hip joints, but interestingly, not from the knee joint when compared with the middle-aged and old adults. These findings indicate that propulsive deficit of ankle contributes most to the age-related locomotor decline. In addition, reduced muscular output from the hip rather than from knee limits the sprinting performance in older age.

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Kim, Jongbin, et Sang-Kyoon Park. « Differences in Physical Characteristics of the Lower Extremity and Running Biomechanics Between Different Age Groups ». International Journal of Environmental Research and Public Health 19, n^o 7 (4 avril 2022) : 4320. http://dx.doi.org/10.3390/ijerph19074320.

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(1) Background: The objective of this study was to determine physical and biomechanical changes in age groups upon running. (2) Method: 75 male adults (20–80s) participated in the study. Bone mineral density and lower extremity joint strength were measured according to age-increase targeting. Based on age, correlations among running characteristics, impulse, impact force, maximum vertical ground reaction force, loading rate, lower extremity joint 3D range of motion, joint moment, and power upon running motion were calculated. (3) Result: Older runners tended to show lower bone mineral density, extremity maximum strength, stride time, and stride distance, with smaller RoM and joint power of ankle and knee joints in the sagittal plane, compared with younger subjects. However, there were no significant correlations between age and impact variables (i.e., impulse, impact force, peak GRF, and loading rate) during running. (4) Conclusion: Older runners tend to show weaker physical strength characteristics, such as bone mineral density and muscle strength and lower joint functionality of ankle and knee joints during running, compared with younger runners. Therefore, strengthening the lower extremity muscle and improving dynamic joint function, especially for ankle joints, can be helpful for injury prevention during running.

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Żur, K. K. « The Maximum Principle of Pontryagin in Control of Twolegged Robot Based on Human Walking System ». International Journal of Applied Mechanics and Engineering 19, n^o 2 (1 mai 2014) : 407–17. http://dx.doi.org/10.2478/ijame-2014-0027.

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Abstract In the paper a hypothesis about state equations of human gait is presented. Instantaneous normalized power developed by human muscles at particular joints of a leg is a control vector in state equations of the human walking system. The maximum principle of Pontryagin in analysis of dynamic human knee joint was presented. The discrete Hamilton function of a knee joint is similar to a discrete square function of normalized power developed by muscles at the knee joint. The results satisfy optimal conditions and could be applied in control of exoskeleton and DAR type robot.

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Naranje, Priyanka, Mahesh Prakash, Aman Sharma, Sunil Dogra et Niranjan Khandelwal. « Ultrasound Findings in Hand Joints Involvement in Patients with Psoriatic Arthritis and Its Correlation with Clinical DAS28 Score ». Radiology Research and Practice 2015 (2015) : 1–9. http://dx.doi.org/10.1155/2015/353657.

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Objective. To determine the frequency of the various ultrasound findings in hand joints in patients with psoriatic arthritis and correlate grayscale and Power Doppler ultrasonography findings with Disease Activity Score 28.Methods. This prospective study was performed in 30 patients. Ultrasound evaluation of 28 joints of both hands was undertaken and various findings were recorded including synovial hypertrophy, Power Doppler abnormality, soft tissue thickening, tendonitis, joint effusion, periosteal reaction, and erosions. Composite ultrasound scores and Disease Activity Score 28 were calculated and compared. Spearman correlation was used to see relationship between the ultrasound and DAS28 scores.Results. Ultrasound detected more abnormalities in the hand joints than did clinical examination. The frequency of various ultrasound abnormalities was as follows: Synovial hypertrophy was seen in 100%, Power Doppler abnormality suggesting hypervascularity was seen in 36.7%, soft tissue thickening was seen in 66.7%, periosteal reaction was seen in 33.3%, erosions were seen in 30% (mostly in DIP and PIP joints), and flexor tendonitis was seen in 6.7% of patients. Significant correlation was found between Disease Activity Score 28 and grayscale joint score (GSJS) (Spearman’sρ: 0.499;P: 0.005), grayscale joint count (GSJC) (ρ: 0.398;P: 0.029), and Power Doppler joint score (PDJS) (ρ: 0.367;P: 0.046). There was a statistically significant difference between remission and low disease activity group and moderate disease activity group in terms of GSJC, GSJS, PDJC, and PDJS (P<0.05). These ultrasound measures were higher in moderate disease activity zone patients.Conclusion. Ultrasound is a useful modality for the objective assessment of psoriatic arthritis. Ultrasound including Power Doppler can be used as a modality for assessment of severity of psoriatic arthritis as it correlates with the clinical scoring.

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Jasna, Dragosavac, Janda Zarko, Gajic Tomislav, Dobricic Sava, Pavlovic Jelena et Arnautovic Dusan. « Joint excitation and reactive power control in thermal power plant ». Zbornik radova, Elektrotehnicki institut Nikola Tesla, n^o 23 (2013) : 85–98. http://dx.doi.org/10.5937/zeint23-4893.

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Singh, Ranjeet, et Er Gora Ram Sharma. « Analysis and Optimization of T Shape Weld Joint Using FEA ». International Journal for Research in Applied Science and Engineering Technology 10, n^o 12 (31 décembre 2022) : 1783–88. http://dx.doi.org/10.22214/ijraset.2022.48154.

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Abstract: The weld joints are used in various types of mechanical and civil engineering structures to strengthen the joints. The strength of T shaped weld joint significantly depends upon the design parameters of weld joint. The current research is intended to investigate the T shaped weld joint using techniques of Finite Element Analysis (FEA). The FEA analysis is conducted on T shaped weld joint using ANSYS simulation package. The optimization studies are conducted on T shaped weld joint to determine the effect weld joint parameters on induced deformation. From the optimization studies, the dimensions corresponding to weld height is determined for maximum and minimum deformation of T shaped weld joint.

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Charles, H. K., et G. V. Clatterbaugh. « Solder Joint Reliability — Design Implications From Finite Element Modeling and Experimental Testing ». Journal of Electronic Packaging 112, n^o 2 (1 juin 1990) : 135–46. http://dx.doi.org/10.1115/1.2904354.

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An extensive finite element modeling and experimental testing program has been carried out to determine the most optimum design parameters for solder joints in surface mount applications. Although the analysis and testing (power cycling and thermal cycling) has been carried out for a variety of package styles, particular attention will be paid to the result for leadless ceramic chip carriers. This package is particularly useful in certain high performance military and commercial applications. Analysis and experimentation indicate that increased fatigue life under power cycling can be attained by fabricating solder joints with large fillets and low standoff heights. The large fillet geometry significantly reduces harmful stress concentrations while increasing the net cross-sectional area within the joint. Both factors tend to improve the fracture toughness of the joint. The temperature and frequency dependencies of solder joint fatigue life under power cycling testing is discussed. The observed frequency dependence can be minimized by eliminating harmful tensile strain components thus reducing harmful stress relaxation and tensile induced oxygen embrittlement of grain boundaries. Temperature cycling studies indicate joints with slightly higher standoffs and low fillet angles are more resistant to cyclic fatigue than pillar type joints which tend to focus shear strains at the interfaces. Solder joints can be tapered to improve overall reliability but, in most cases, tapering will provide only a small increase in fracture toughness of the joint through the elimination of stress concentrations. Additional fatigue life increases can be obtained only through an enlargement of the joint cross-sectional area. Aspects of the above results will be presented in detail along with design guidelines for creating high reliability solder joints for various application scenarios.

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Dolganova, T. I., D. A. Popkov, D. V. Dolganov et G. M. Chibirov. « Indicators of the kinetics of locomotor stereotypes in healthy children in different speed ranges of movement ». Genij Ortopedii 28, n^o 3 (juin 2022) : 417–24. http://dx.doi.org/10.18019/1028-4427-2022-28-3-417-424.

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Purpose To determine the normative values of the kinetic parameters of gait in healthy children in different speed ranges of movement. Materials and methods Locomotor profile assessment by video gait analysis (CGA) was performed on an outpatient basis in 27 children (54 limbs), aged 10–13 years. The following variables were used and processed: peak negative hip, knee and ankle power (W/kg) (relaxation); peak positive power of the hip, knee and ankle (support push) joints (W/kg) (generation); the total positive and total negative power was calculated(for the hip, knee and ankle joints); total peak power; net peak power values and overall mechanical efficiency. Kinetics indicators were generalized according to the ranges of ranking of the absolute walking speed (km/h), taking into account the weight of patients. Quantitative characteristics are presented in the table as a median, percentile range of distribution of values (25÷75 %) and the number of observations (n) equal to the number of limbs. Results The normative kinetic parameters of gait are presented at a speed of movement in the range from 1.1 to 5.0 km/h in healthy children aged 10–13 years. A strong correlation was found between the values of the power of the reference shock during the formation of the reciprocal inhibition reflex of the shin sprain and the speed parameters of movement (r = -0.925, n = 142 and p < 0.001). To change the speed of movement, the motor locomotor stereotype was changed with the redistribution of the load from one joint muscle to another. If the share of the contribution of the power of the muscles of the hip joint increased, on average, by 10.8 %, and of the knee joint – by 15.3 %, then the share of the contribution of the ankle joint decreased by 16.8 %. Discussion In locomotor stereotypes in the examined children, a significant positive correlation was found between walking speed and the total (r = 0.907, n = 104) and useful peak power (r = 0.475, n = 104) of the joint muscles, while the maximum median values of the useful total peak the power of all joint muscles was recorded at a speed of movement in the range from 3.1 to 4.0 km/h.

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Milosavljevic, J., U. Lindqvist et A. Elvin. « Ultrasound and power doppler evaluation of the hand and wrist in patients with psoriatic arthritis ». Acta Radiologica 46, n^o 4 (juillet 2005) : 374–85. http://dx.doi.org/10.1080/02841850510021256.

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Purpose: To evaluate the ability of high‐resolution and power Doppler sonography in detecting joint and tendon abnormalities in patients with psoriatic arthritis (PsA) of the hands and wrists compared with clinical and radiological findings. Material and Methods: Thirty‐six patients with psoriatic arthritis of the hands and wrists and 10 healthy controls were examined with ultrasound (US). The degree of synovial proliferation, tenosynovitis, presence of joint effusion as well as the vascularity of synovial tissue was estimated. US findings were scored using a newly devised scoring system. Results: Thirty‐two patients had articular synovial proliferation and/or tenosynovitis/tendinitis or joint effusion in one or more joints according to US. Twenty‐two patients had tendon changes; only five had joint effusion. The synovial, Doppler, and total articular‐teno scores were all significantly correlated to the number of swollen joints. The scores, however, did not correlate to other clinical or laboratory measurements of disease activity. Conclusion: US proved effective in demonstrating PsA involvement of the hands and wrists and was more sensitive than clinical examination in detecting pathology. Long‐term follow‐up studies are needed to evaluate whether this can change the traditional approach for assessing involvement of joints and tendons in PsA.

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Fang, Qingyuan, Yong Han, Ming Jin et Wenyi Dong. « Joint DOA and Polarization Estimation for Unequal Power Sources ». International Journal of Antennas and Propagation 2015 (2015) : 1–9. http://dx.doi.org/10.1155/2015/471374.

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For most joint direction of arrival (DOA) and polarization estimation methods, the performances of proposed methods in dealing with unequal power sources are not discussed. However, sources with unequal powers apparently exist widely in actual applications. In this study, we propose a joint DOA and polarization estimation method for unequal power sources by utilizing the invariance property of noise subspace (IPNS) to the power of sources. This work extends the IPNS method to the dual polarized antenna array for joint DOA and polarization estimation. Moreover, we theoretically prove that the IPNS remains valid even when the sources are correlated. The computer simulations illustrate that the proposed method can effectively estimate the DOA and polarization parameters as the power difference between sources increases, as opposed to the polarimetric multiple signal classification (MUSIC) algorithm, which suffers from degradation in resolution probability. In addition, the performances of the proposed method are provided, as well the Cramer Rao Bound (CRB), which show approximate performance as the polarimetric MUSIC algorithm.

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LIU, YANG, YONGSHENG GAO et YANHE ZHU. « A NOVEL CABLE-PULLEY UNDERACTUATED LOWER LIMB EXOSKELETON FOR HUMAN LOAD-CARRYING WALKING ». Journal of Mechanics in Medicine and Biology 17, n^o 07 (novembre 2017) : 1740042. http://dx.doi.org/10.1142/s0219519417400425.

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Wearable lower limb exoskeleton has comprehensive applications such as load-carrying augmentation, walking assistance, and rehabilitation training by using many active actuators in the joints to reduce the metabolic cost generally. The traditional fully actuated exoskeleton is bulky and requires large energy consumption, and the passive exoskeleton is difficult to provide effective power assistance. To achieve both small number of actuators and good assisting performance, this paper proposes a cable-pulley underactuated principle-based lower limb exoskeleton. The exoskeleton dynamics was modeled and the human-exoskeleton hybrid model was analyzed via ADAMS and LifeMOD to provide an evaluation method for power assistance. By exploiting the control strategy and utilizing the synergies of torque and power assistance, the hip joint and the knee joint can be actuated by a single cable simultaneously. Moreover, the human-exoskeleton co-simulation method was utilized to verify the assisting performance and control effect. In this simulation, the upper toque peak and power required by human are obviously reduced by power assistance and the joint angle curves without exoskeleton are in accordance with the joint angle curves with exoskeleton almost. In conclusion, the designed exoskeleton is compatible with human motion and feasible to provide effective power assistance in load-carrying walking.

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Narsimhachary, D., S. M. Shariff, Snehanshu Pal, G. Padmanabham et Anindya Basu. « Influence of Joint Configuration on Mechanical Properties of Laser Weld-Brazed Aluminum to Steel Joint ». Materials Science Forum 978 (février 2020) : 174–80. http://dx.doi.org/10.4028/www.scientific.net/msf.978.174.

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In the present work, laser weld-brazing experiments were performed to produce aluminum to galvanized steel joints in lap and flange configuration. Tests were carried out using Al-12 % Si eutectic filler wire for joining of AA6082 -T6 with galvanized steel with varying laser power and keeping other parameters (wire feed and laser scan speed) constant. Microstructural characteristics of the laser brazed joints, studied by SEM, revealed cast structure in the brazed zone. Intermetallic formed at the steel interface was non-uniform. From the hardness results, it was noted that the brazed region exhibits lower hardness compared to the base material. The wetting length was improved with increasing filler wire rate, which in turn improved the strength of the brazed joint in both the configuration (lap and flange). At 4 kW laser power, flange configuration sample has failed in AA6082 whereas, in case lap joint, failed in the heat affected zone of AA6082.

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He, Pengfei, Wenfeng Du, Longxuan Wang, Ravi Kiran et Mijia Yang. « Additive Manufacturing and Mechanical Performance of Trifurcated Steel Joints for Architecturally Exposed Steel Structures ». Materials 13, n^o 8 (17 avril 2020) : 1901. http://dx.doi.org/10.3390/ma13081901.

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Additive Manufacturing (AM) technology has unique advantages in producing complex joints in architecturally exposed steel structures. This article focuses on the process of manufacturing and investigating the mechanical properties of a reduced scale model of a trifurcated joint using Selective Laser Melting (SLM) method and mechanical tests, respectively. The orthogonal test method was used to optimize the main AM process parameters. Then the trifurcated steel joint was printed using the optimal process parameters and treated by solid solution and aging treatment. To investigate the mechanical performance of the printed joint, an axial compression test and complimentary finite element analyses were carried out. Failure processes and failure mechanisms of the trifurcated steel joint were discussed in detail. The research results show that the preferred process parameters for printing 316L stainless steel powder are: scanning power 150 W, scanning speed 700 mm/s, and scanning pitch 0.09 mm. Using these AM parameters, trifurcated steel joints with good surface quality, geometrical accuracy and tensile strength are obtained after heat treatment. Our mechanical tests and Finite element analyses results indicate that the failure mechanism in the AM trifurcated joint are similar to those of cast steel joints. Based on these results, we conclude that the AM technology serves as a promising new way for the fabrication of joints with complex geometries.

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Ishii, Mineo, Keijiro Yamamoto et Kazuhito Hyodo. « Stand-Alone Wearable Power Assist Suit –Development and Availability– ». Journal of Robotics and Mechatronics 17, n^o 5 (20 octobre 2005) : 575–83. http://dx.doi.org/10.20965/jrm.2005.p0575.

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The stand-alone wearable power assist suit we developed gives caregivers the extra strength they need to lift patients while avoiding back injuries. To put this suit to practical use, we improved sensing system and the mechanisms. To stabilize muscle tenseness sensing more, we developed an all-in-one sensor that built the sensor into a mesh belt and improved sensing characteristics. We expanded the movable range and function of the suit. We increased actuator output torque by increasing the number of cuffs inserted into actuators. Based on equations derived from static body mechanics using joint angles, joints torques required to maintain a position are calculated by an embedded microcomputer and required joint torques was combined with muscle sensor output signals to generate control signals. We developed an exoskeleton for measurement having the same frame and potentiometers as the suit and measured muscle force by having a user wear the exoskeleton, and proved that each unit of the suit transmitted assistance torque directly to each joint. We also found that a user wearing the suit could lift weight using half or less muscle power, i.e., muscle power doubled.

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Itani, Ryo, et Takashi Iizuka. « Joint Strength of SPCC/A5052P-H Joint Welded by Laser Butt Welding with Compression ». Key Engineering Materials 554-557 (juin 2013) : 86–92. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.86.

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Welding properties of a tailored blank which consists of dissimilar metals are interesting because of the possible benefits for light weight design of materials. Especially, the combination of mild steel and aluminum alloy is expected as a representative of such a light hybrid material.Recently, our research team has developed a butt laser welding method with compression using CO2 laser. Joint strength of mild steel/industrial aluminum alloy joints welded by this method has not been reported in detail. In this study, variations of joint strength of SPCC/A5052 joints by welding conditions, i.e. laser power, pulse frequency and butt compressive stress, were investigated. Furthermore, the welded interface of a SPCC/A5052 joint obtained was observed and analyzed using FE-SEM and EDS.

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Nguyen, Quang Luc, Hoang Thanh Van Nguyen et Hoang Minh Nguyen. « POWER DOPPLER ULTRASOUND FEATURESOF WRIST JOINTS IN RHEUMATOID ARTHRITIS ». Volume 8 Issue 3 8, n^o 3 (juin 2018) : 90–94. http://dx.doi.org/10.34071/jmp.2018.3.14.

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Background and aims: Assessments of disease activity in rheumatoid arthritis plays an important role in determining treatment plans and patient response to treatment. The aims of this study was to describe the power Doppler ultrasound features of wrist joints in patients with rheumatoid arthritis and evaluate role of power Doppler ultrasoundin assessing disease activity in patients withrheumatoid arthritis. Material and method: This present study included 30patients diagnosed with rheumatoid arthritis according to the 2010 ACR/EULAR classification criteria, who were admitted in the period July 2017 to April 2018 in Department of Nephrology and Rheumatology, Hue Central Hospital. All patients were physical examination, laboratory investigations, assessment disease activity score in 28 joints using CRP (DAS28-CRP), clinical disease activity index (CDAI), simplified disease activity index (SDAI). Grey scale ultrasound and power Doppler ultrasound were used to assess synovitis, effusion and tenosynovitis and synovial vascularity of 60 wrist joints. Power Doppler was graded using a validated semiquantitative scroring system, which consists of scale of 0-3. Result: Twenty-seven wrist joints (45.0%) had synovitis in grey scale ultrasound. Thirty-seven wrist joints (61.7%) had a power doppler signal, 18.3% had grade 1 (low), 21.7% had grade 2 (moderate) and 21.7% had grade 3 (high). Level of angiogenesis in PDUS with semiquantitative scroring systemweresignificantly correlated with tender joint count, swollen joint count, global VAS, CRP and CDAI, SDAI, DAS28-CRP. Conclusions: Power Doppler ultrasound of wrist joints could be used as a non-invasive and feasible method to assessing disease activity in patients with rheumatoid arthritis. Key words: rheumatoid arthritis, power Doppler ultrasound

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Valencia, Jonathan, et Joel Cort. « Psychophysically Based Physical Capability Limits For Right Angle Power Tool Operation ». Proceedings of the Human Factors and Ergonomics Society Annual Meeting 64, n^o 1 (décembre 2020) : 910–14. http://dx.doi.org/10.1177/1071181320641217.

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A psychophysical methodology was utilized to examine 40 non-skilled female participants performing right-angle power tool (RAPT) fastening tasks. A combination of two between subject variables were examined for a total of four between-subject groups: joint orientation (horizontal and vertical planes) and joint hardness (hard and soft joints). Participants were evenly distributed into one of four joint orientation- hardness groups. Within each group, a combination of three fastening strategies and three fastening frequencies were performed by each participant. The chosen target torque determined the physical capability limits (PCL). A mixed-design repeated analysis of variance with Tukey’ significance post hoc test were used to determine any significance with the measured variables ( p<0.05). Fastening strategy and frequency influenced the chosen torque magnitude. Participants chose significantly higher target torques with the Turbo Tight strategy in comparison to the other two strategies. Furthermore, participants chose to accept lower target torques and forces as fastening frequency increased.

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Ma, Wanping, Xiaohong Zhan, Hongyan Yang, Hengchang Bu, Yun Li et Feiyun Wang. « Study on the interface morphology in the induction welding joint of PEEK plate at low power ». Journal of Polymer Engineering 40, n^o 5 (26 mai 2020) : 432–39. http://dx.doi.org/10.1515/polyeng-2020-0011.

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AbstractInduction welding is an important joining technique with potentially significant application in the connection of the Poly Ether Ether Ketone (PEEK). The present research employs the metal mesh as induction components into the induction welding of PEEK plate to PEEK plate at low power successfully. Besides, the examinations and analyses of macro/micro-structures, energy dispersive spectroscopy (EDS) and mechanical tensile properties of the joints are conducted. Meanwhile, the characteristics and formation mechanisms of the lap-welded interface structures are interpreted in detail. The results indicate that the interface morphology of the welded joint is of high quality at low power, which most of the interface area is tightly connected due to the element diffusion. Besides, the connection mechanism of the joint is bonding connection and mechanical engagement, which plays a major role in a great performance joint. Furthermore, the tensile fracture of the joint occurs in the heat-affected zone, which contributes to a high joint tensile strength.

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Dobie, Monica. « Using the power of the knee joint ». Nursing Standard 22, n^o 47 (30 juillet 2008) : 28. http://dx.doi.org/10.7748/ns.22.47.28.s33.

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Ohtsu, Shinki. « Vibroisolating handle joint structure for power tool ». Journal of the Acoustical Society of America 91, n^o 5 (mai 1992) : 3084. http://dx.doi.org/10.1121/1.402913.

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