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Ma, Richard, Mark Stasiak, Xiang-Hua Deng, and Scott Rodeo. "A Preclinical Model to Study the Influence of Graft Force on the Healing of the Anterior Cruciate Ligament Graft." Journal of Knee Surgery 32, no. 05 (May 4, 2018): 441–47. http://dx.doi.org/10.1055/s-0038-1646931.
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AbstractThe purpose of this study is to establish a small animal anterior cruciate ligament (ACL) reconstruction research model where ACL graft force can be varied to create different graft force patterns with controlled knee motion. Cadaveric (n = 10) and in vivo (n = 10) rat knees underwent ACL resection followed by reconstruction using a soft tissue autograft. Five cadaveric and five in vivo knees received a nonisometric, high-force femoral graft tunnel position. Five cadaveric and five in vivo knees received a more isometric, low-force graft tunnel position. ACL graft force (N) was then recorded as the knee was ranged from extension to 90 degrees using a custom knee flexion device. Our results demonstrate that distinct ACL graft force patterns were generated for the high-force and low-force femoral graft tunnels. For high-force ACL grafts, ACL graft forces increased as the knee was flexed both in cadaveric and in vivo knees. At 90 degrees of knee flexion, high-force ACL grafts had significantly greater mean graft force when compared with baseline (cadaver: 7.76 ± 0.54 N at 90 degrees vs. 4.94 ± 0.14 N at 0 degree, p = 0.004; in vivo: 7.29 ± 0.42 N at 90 degrees vs. 4.74 ± 0.13 N at 0 degree, p = 0.007). In contrast, the graft forces for low-force ACL grafts did not change with knee flexion (cadaver: 4.94 ± 0.11 N at 90 degrees vs. 4.72 ± 0.14 N at 0 degree, p = 0.41; in vivo: 4.78 ± 0.26 N at 90 degrees vs. 4.77 ± 0.06 N at 0 degree, p = 1). Compared with nonisometric ACL grafts, the graft force for grafts placed in an isometric position had significantly lower ACL graft forces at 15, 30, 45, 60, 70, and 90 degrees in both cadaveric and in vivo knees. In conclusion, we have developed a novel ACL reconstruction model that can reproducibly produce two ACL graft force patterns. This model would permit further research on how ACL graft forces may affect subsequent graft healing, maturation, and function.
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Barnes, Josh, and Piet Hut. "A hierarchical O(N log N) force-calculation algorithm." Nature 324, no. 6096 (December 1986): 446–49. http://dx.doi.org/10.1038/324446a0.
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Martin, Bernard J., Thomas J. Armstrong, James A. Foulke, Sivakumaran Natarajan, Edward Klinenberg, Elaine Serina, and David Rempel. "Keyboard Reaction Force and Finger Flexor Electromyograms during Computer Keyboard Work." Human Factors: The Journal of the Human Factors and Ergonomics Society 38, no. 4 (December 1996): 654–64. http://dx.doi.org/10.1518/001872096778827288.
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This study examines the relationship between forearm EMGs and keyboard reaction forces in 10 people during keyboard tasks performed at a comfortable speed. A linear fit of EMG force data for each person and finger was calculated during static fingertip loading. An average r2 of .71 was observed for forces below 50% of the maximal voluntary contraction (MVC). These regressions were used to characterize EMG data in force units during the typing task. Averaged peak reaction forces measured during typing ranged from 3.33 N (thumb) to 1.84 N (little finger), with an overall average of 2.54 N, which represents about 10% MVC and 5.4 times the key switch make force (0.47 N). Individual peak or mean finger forces obtained from EMG were greater (1.2 to 3.2 times) than force measurements; hence the range of r2 for EMG force was .10 to .46. A closer correspondence between EMG and peak force was obtained using EMG averaged across all fingers. For 5 of the participants the force computed from EMG was within ±20% of the reaction force. For the other 5 participants forces were overestimated. For 9 participants the difference between EMG estimated force and the reaction force was less than 13% MVC. It is suggested that the difference between EMG and finger force partly results from the amount of muscle load not captured by the measured applied force.
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Portone, Alfredo. "Force scaling for n = 0 RWMs." Nuclear Fusion 59, no. 2 (January 9, 2019): 024002. http://dx.doi.org/10.1088/1741-4326/aaf54e.
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Figueroa, K., R. Peña, and M. M. Campos-Vallette. "Valence Force Constants of N-Benzylideneanilines." Zeitschrift für Naturforschung B 44, no. 8 (August 1, 1989): 923–27. http://dx.doi.org/10.1515/znb-1989-0811.
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Valence force constants for N-benzylideneaniline and for two p,p′-disubstituted derivatives were estimated by means of a point-charge model using CNDO data. A vibrational assignment of bands which are sensitive to the electron donor-acceptor characteristic of substituents is proposed. The conformational changes are interpreted in terms of an intramolecular energy transfer between substituents.
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Dehnen, Walter. "A Hierarchical (N) Force Calculation Algorithm." Journal of Computational Physics 179, no. 1 (June 2002): 27–42. http://dx.doi.org/10.1006/jcph.2002.7026.
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Jung, Kihyo, Byung Hwa Lee, Sang Won Seo, Doo Sang Yoon, Baekhee Lee, Duk L. Na, and Heecheon You. "Quantitative Assessment Method of Force Tracking Capabilities for Detection of Motor Intentional Disorders." Applied Sciences 11, no. 7 (April 5, 2021): 3244. http://dx.doi.org/10.3390/app11073244.
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Early detection of motor intentional disorders associated with dysfunction in the action–intention system of the brain is clinically important to provide timely intervention. This study developed a force tracking system that can record forces exerted by the index finger while tracking 5 N, 10 N, 15 N, and 20 N of target forces varying over time. The force tracking system quantified force control measures (initiation time IT; development time, DT, maintenance error, ME; termination time, TT; tracking error, TE) for the individual and overall force control phases. This study evaluated the effectiveness of the force tracking system for a normal control group (n = 12) and two patient groups diagnosed with subcortical vascular mild cognitive impairment (svMCI, n = 11) and subcortical vascular dementia (SVaD, n = 13). Patients with SVaD showed significantly worse force control capabilities in IT (0.84 s) and ME (1.71 N) than those with svMCI (0.64 s in IT, and 1.38 N in ME). Patients with svMCI had significantly worse capabilities in IT, ME, and TE (3.80 N) than the control group (0.49 s in IT, 0.78 N in ME, and 3.07 N in TE). The prevalence rates of force control capabilities lower than the 99% confidence interval of the control group ranged from 17% to 62% for the two patient groups. The force tracking system can sensitively quantify the severity of the force control deficiencies caused by dysfunction in the action–intention system of the brain.
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Nguyen, Yann, Guillaume Kazmitcheff, Daniele De Seta, Mathieu Miroir, Evelyne Ferrary, and Olivier Sterkers. "Definition of Metrics to Evaluate Cochlear Array Insertion Forces Performed with Forceps, Insertion Tool, or Motorized Tool in Temporal Bone Specimens." BioMed Research International 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/532570.
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Introduction. In order to achieve a minimal trauma to the inner ear structures during array insertion, it would be suitable to control insertion forces. The aim of this work was to compare the insertion forces of an array insertion into anatomical specimens with three different insertion techniques: with forceps, with a commercial tool, and with a motorized tool.Materials and Methods. Temporal bones have been mounted on a 6-axis force sensor to record insertion forces. Each temporal bone has been inserted, with a lateral wall electrode array, in random order, with each of the 3 techniques.Results. Forceps manual and commercial tool insertions generated multiple jerks during whole length insertion related to fits and starts. On the contrary, insertion force with the motorized tool only rose at the end of the insertion. Overall force momentum was 1.16 ± 0.505 N (mean ± SD,n=10), 1.337 ± 0.408 N (n=8), and 1.573 ± 0.764 N (n=8) for manual insertion with forceps and commercial and motorized tools, respectively.Conclusion. Considering force momentum, no difference between the three techniques was observed. Nevertheless, a more predictable force profile could be observed with the motorized tool with a smoother rise of insertion forces.
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Katsyuba, S. A., L. V. Awakumova, D. A. Pudovik, I. Kh Shakirov, and R. R. Shagidullin. "Vibrational spectra and force constants ofS-methyl-N,N-dimethyldithiocarbamate." Russian Chemical Bulletin 44, no. 6 (June 1995): 1068–71. http://dx.doi.org/10.1007/bf00707054.
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Fox, Ross J., Christopher D. Harner, Masataka Sakane, Gregory J. Carlin, and Savio L.-Y. Woo. "Determination of the In Situ Forces in the Human Posterior Cruciate Ligament Using Robotic Technology." American Journal of Sports Medicine 26, no. 3 (May 1998): 395–401. http://dx.doi.org/10.1177/03635465980260030901.
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We examined the in situ forces in the posterior cruciate ligament as well as the force distribution between its anterolateral and posteromedial bundles. Using a robotic manipulator in conjunction with a universal force-moment sensor system, we applied posterior tibial loads from 22 to 110 N to the joint at 0° to 90° of knee flexion. The magnitude of the in situ force in the posterior cruciate ligament and its bundles was significantly affected by knee flexion angle and posterior tibial loading. In situ forces in the posterior cruciate ligament ranged from 6.1 6.0 N under a 22-N posterior tibial load at 0° of knee flexion to 112.3 28.5 N under a 110-N load at 90°. The force in the posteromedial bundle reached a maximum of 67.9 31.5 N at 90° of knee flexion, and the force in the anterolateral bundle reached a maximum of 47.8 23.0 N at 60° of knee flexion under a 110-N load. No significant differences existed between the in situ forces in the two bundles at any knee flexion angle. This study provides insight into the knee flexion angle at which each bundle of the posterior cruciate ligament experiences the highest in situ forces under posterior tibial loading. This information can help guide us in more accurate graft placement, fixation, and tensioning, and serve as an assessment of graft performance.
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Nawaz, Muhammad Sohaib, Nazia Yazdanie, Shafqat Hussain, Muhammad Moazzam, Muhammad Haseeb, and Muhammad Hassan. "Maximum Voluntary Bite Force Generated by Individuals with Healthy Dentition and Normal Occlusion." Journal of the Pakistan Dental Association 29, no. 04 (November 3, 2020): 199–204. http://dx.doi.org/10.25301/jpda.294.199.
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OBJECTIVE: Masticatory muscles work coordinately along with bones and teeth in these jaws to generate occlusal bite force. The amount of force varies from person to person. This study was performed to measure the amount of bite force to associated with demographics like age and gender so that we may compare it with prosthodontically rehabilitated dentition which may help us in the treatment plan. METHODOLOGY: Bite force was recorded with an Occlusal Bite force meter (GM-10 Nagano Keiki Japan). A sample of 204 Pakistani individuals who are aged between 13 to 40 years and divided into three age groups: I (13-20years), II (21-30 years), III (31-40 years) is recorded. A mean of three left sided and a mean of three right sided maximum voluntary bite forces were calculated and a final mean of the two were taken to find out the Mean Maximum Voluntary Bite force. RESULTS: Mean Maximum Voluntary Bite Force was calculated as 533.42 N ± 185.44 N, whereas Males have Mean MVBF 635.23 N ± 179.86 N and Females have Mean MVBF 431.61 N ± 125.82 N. Mean Maximum Voluntary Bite force with respect to age; group I is 476.11 N ± 181.27 N, group II is 550.93 N ± 191.83 N. MVBF of group 3 is 573.21 N ± 171.18 N. CONCLUSION: Mean MVBF with standard deviation was calculated as 533.42 N ± 185.44 N, with males having bite force significantly higher than the females. In all the groups, gender was significantly associated with MVBF. The bite force is also positively correlated with age. KEYWORDS: Bite force, Human Bite force, bite force gauge, maximum bite force HOW TO CITE: Nawaz MS, Yazdanie N, Hussain S, Moazzam M, Haseeb M, Hassan M. Maximum voluntary bite force generated by individuals with healthy dentition and normal occlusion. J Pak Dent Assoc 2020;29(4):199-204.
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Shope, Alexander J., Joshua S. Winder, Jonathan T. Bliggenstorfer, Kristen T. Crowell, Randy S. Haluck, and Eric M. Pauli. "Force Comparison of Commercially Available Transfascial Suture Passers." Surgical Innovation 24, no. 3 (February 8, 2017): 301–8. http://dx.doi.org/10.1177/1553350617691709.
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Background. Transfascial suture passers (TSPs) are a commonly used surgical tool available in a wide array of tip configurations. We assessed the insertion force of various TSPs in an ex vivo porcine model. Methods. Uniform sections of porcine abdominal wall were secured to a 3D-printed platform. Nine TSPs were passed through the abdominal wall both without and with prolene suture under the following scenarios: abdominal wall only and abdominal wall plus underlay ePTFE or composite ePTFE/polypropylene mesh. Insertion forces were recorded in Newton (N). Results. When passed without suture through the abdominal wall, smaller diameter TSPs required less insertional force (1.50 ± 0.17 N vs 9.68 ± 1.50 N [ P = 0.00072]). Through composite mesh, the solid tipped TSPs required less force than hollow tipped ones (3.87 ± 0.25 N vs 7.88 ± 0.20 N [ P = 0.00026]). Overall, smaller diameter TSPs required less force than the larger TSPs when passed through ePTFE empty (Gore 2.95 ± 0.83 N vs Carter-Thomason 16.07 ± 2.10 N [ P = .0005]) or with suture (Gore 8.37 ± 2.59 N vs Carter-Thomason 19.12 ± 1.10 N [ P = .003]). Conclusions. Diameter plays the greatest role in the force required for TSP penetration. However, when passed through underlay mesh or while holding suture, distal tip shape, the mechanism of suture holding, and shaft diameter all contribute to the forces necessary for penetration. These factors should be considered when choosing a TSP for intraoperative use.
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GAVIN, E. J. O., H. FIEDELDEY, and S. A. SOFIANOS. "THREE-BODY FORCES FROM n-BODY INVERSION." International Journal of Modern Physics E 04, no. 02 (June 1995): 431–41. http://dx.doi.org/10.1142/s0218301395000158.
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Within the context of the lowest order approximation to the calculation of the n-body bound state in the Hyperspherical Harmonic Expansion Method, the hypercentral potential may be determined from n-body spectral data. Previously, we showed how the two-body force can be determined exactly from the hypercentral potential in the absence of three-body forces. In this paper, we investigate to what extent the three-body force can be determined if the two-body force is assumed to be known. For this purpose, a three-quark system is considered.
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Zhangfeng, Zhao, Li Yanbiao, Li Wenhao, Zhan Xian, Zhu Xingliang, and Zhong Jiang. "Research on the biaxial compound pendulum jaw crusher based on seven-bar mechanism." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 11 (April 16, 2015): 1876–89. http://dx.doi.org/10.1177/0954406215583889.
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Traditional compound pendulum jaw crushers have many disadvantages such as low efficiency and uneven broken materials. This paper proposes a new biaxial compound pendulum jaw crusher to solve these problems. This paper presents the kinematic and dynamic performance of the new crushers, introduces its structure and layout features, derives the equations involving position, velocity, acceleration and kinetics, describes a workspace of the jaw crusher, analyzes the travel characteristic values and crushing force of movable jaw plates, and optimizes its structural and motion parameters through a multi-objective genetic algorithm. After the optimization process, the novel jaw crusher has little force on each hinge and large force on movable jaw plates. Specifically, the forces in the X-direction are 120,300 N for hinge C, 120,200 N for hinge D, and 195,000 N for hinge N; the forces in the Y-direction are 167,100 N, 162,800 N, and 197,900 N accordingly, while the breaking force of the movable jaw plate is 229,600 N. Experiments have been conducted. The results have clearly shown that the new biaxial compound pendulum jaw crusher has many advantages over conventional ones, such as the high crushing efficiency, even crushing, and large crushing force.
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Quaney, Barbara M., Randolph J. Nudo, and Kelly J. Cole. "Can Internal Models of Objects be Utilized for Different Prehension Tasks?" Journal of Neurophysiology 93, no. 4 (April 2005): 2021–27. http://dx.doi.org/10.1152/jn.00599.2004.
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We examined if object information obtained during one prehension task is used to produce fingertip forces for handling the same object in a different prehension task. Our observations address the task specificity of the internal models presumed to issue commands for grasping and transporting objects. Two groups participated in a 2-day experiment in which they lifted a novel object (230 g; 1.2 g/cm3). On Day One, the high force group (HFG) lifted the object by applying 10 N of grip force prior to applying vertical lift force. This disrupted the usual coordination of grip and lift forces and represented a higher grip force than necessary. The self-selected force group (SSFG) lifted the object on Day One with no instructions regarding their grip or lift forces. They first generated grip forces of 5.8 N, which decreased to 2.6 N by the 10th lift. Four hours later, they lifted the same object in the manner of the HFG. On Day Two, both groups lifted the same object “naturally and comfortably” with the opposite hand. The SSFG began Day Two using a grip force of 2.5 N, consistent with the acquisition of an accurate object representation during Day One. The HFG began Day Two using accurately scaled lift forces, but produced grip forces that virtually replicated those of the SSFG on Day One. We concur with recent suggestions that separate, independently adapted internal models produce grip and lift commands. The object representation that scaled lift force was not available to scale grip force. Furthermore, the concept of a general-purpose object representation that is available across prehension tasks was not supported.
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Namnabat, Majid, Amir Hossein Zaeri, and Mohammad Vahedi. "Sliding Mode Contact Force Control of n-Dof Robotics by Force Estimation." Majlesi Journal of Electrical Engineering 14, no. 4 (December 1, 2020): 1–9. http://dx.doi.org/10.29252/mjee.14.4.1.
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Smit, Gerwin, and Dick H. Plettenburg. "Efficiency of Voluntary Closing Hand and Hook Prostheses." Prosthetics and Orthotics International 34, no. 4 (December 2010): 411–27. http://dx.doi.org/10.3109/03093646.2010.486390.
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The Delft Institute of Prosthetics and Orthotics has started a research program to develop an improved voluntary closing, body-powered hand prosthesis. Five commercially available voluntary closing terminal devices were mechanically tested: three hands [Hosmer APRL VC hand, Hosmer Soft VC Male hand, Otto Bock 8K24] and two hooks [Hosmer APRL VC hook, TRS Grip 2S]. The test results serve as a design guideline for future prostheses. A test bench was used to measure activation cable forces and displacements, and the produced pinch forces. The measurements show that the hands require higher activation forces than the hooks and 1.5–8 times more mechanical work. The TRS hook requires the smallest activation force (33 N for a 15 N pinch force) and has the lowest energy dissipation (52 Nmm). The Hosmer Soft hand requires the largest activation force (131 N for a 15 N pinch force) and has the highest energy dissipation (1409 Nmm). The main recommendations for future prostheses are the following: (1) Required activation forces should be below the critical muscle force (∼ 18% of maximum), to enable continuous activation without muscle fatigue; and (2) hysteresis of mechanism and glove should be lowered, to increase efficiency and controllability.
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Pfeiffer, Thomas, Jan-Hendrik Naendrup, Kanto Nagai, Joao Novaretti, Calvin Chan, Richard Debski, and Volker Musahl. "Effect of Meniscal Ramp Lesion Repair on Knee Kinematics, ACL In-Situ Forces and Bony Contact Forces – A Biomechanical Study." Orthopaedic Journal of Sports Medicine 7, no. 6_suppl4 (June 1, 2019): 2325967119S0023. http://dx.doi.org/10.1177/2325967119s00237.
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Aims and Objectives: While recent studies showed that all inside meniscal ramp repair is able to restore knee kinematics, the effects of ramp repairs on ACL in-situ forces and bony contact forces is still unclear. Therefore, the purpose of this study is to determine the effect of ramp lesion repair on knee kinematics, the ACL-ISF and bony contact forces using a 6-degree-of-freedom (DOF) robotic testing system. It was hypothesized that ramp repair will restore kinematics, ACL-ISF and bony contact forces comparably to the forces of the intact knee. Materials and Methods: Nine fresh-frozen human cadaveric knee specimens were tested using a 6-degree-of-freedom robotic testing system (FRS2010) to continuously flex the knee from full extension to 90° and apply continuous loading conditions: 1) 90 N of anterior force, 2) 5 Nm of external rotation torque, 3) 134 N anterior force + 200 N compression force, 4) 4 Nm external rotation torque + 200 N compression force, 5) 4 Nm internal rotation torque + 200 N compression force. Loading conditions were applied to the intact knee, a knee with an arthroscopically induced 25 mm ramp lesion, and a knee with an all-inside repaired ramp lesion. ACL in-situ forces, medial compartment bony contact forces and lateral compartment bony contact forces were quantified. Repeated measure ANOVAs were performed to compare knee states at each flexion angle (p<0.05). Results: In response to all loading conditions, no differences with respect to kinematics, ACL in-situ forces, and bony contact forces between the intact state and the ramp lesion state were detected. However, compared to the intact state, ramp lesion repair significantly reduced anterior translation in flexion angles from full extension to 40° in response to 5 N anterior force (p < 0.05). In addition, a significant decrease in the ACL in-situ forces after ramp repair was detected only for higher flexion angles when 4 Nm external rotation torque combined with 200 N compression force (p < 0.05) and when 4 Nm internal rotation torque combined with 200 N compression force were applied (p < 0.05). Conclusion: In this biomechanical study, ramp lesions did not significantly affect knee biomechanics. Care must be taken to avoid potential overconstraint when performing all-inside ramp lesion repairs. From biomechanical time-zero perspective, it is debatable if stable ramp lesions need to be addressed surgically. As stable ramp lesions do not significantly change knee biomechanics, the indications for ramp lesion repair may be limited.
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Shao, Ming Xi, and Xiu Mei Zhang. "N-C Lathe Cutting Force Measurement Research." Applied Mechanics and Materials 457-458 (October 2013): 608–11. http://dx.doi.org/10.4028/www.scientific.net/amm.457-458.608.
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through the use of single-chip microcomputer measurement CNC lathe cutting force, this paper focuses on the single chip microcomputer to implement continuous automatic sampling, A/D conversion, scale transformation and data processing methods. Introduces the principle of the measurement and control system, structure and data acquisition part of the program.
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Balakrishnan, V., Suresh Govindarajan, and S. Lakshmibala. "The Central Force Problem in n Dimensions." Resonance 25, no. 4 (April 2020): 513–38. http://dx.doi.org/10.1007/s12045-020-0968-0.
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Proeschel, P. A., and T. Morneburg. "Task-dependence of Activity/ Bite-force Relations and its Impact on Estimation of Chewing Force from EMG." Journal of Dental Research 81, no. 7 (July 2002): 464–68. http://dx.doi.org/10.1177/154405910208100706.
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Estimation of chewing force from electromyograms (EMGs) calibrated in isometric biting yielded strikingly high force values. We tested the hypothesis that EMG-based force predictions are excessive because of differing activity/bite-force relations in mastication and isometric biting. In nine patients, unilateral bite forces and EMGs of 4 elevator muscles were recorded during chewing and isometric clenching on a bite-fork. We estimated chewing force by substituting chewing EMGs of each muscle into isometric activity/bite-force regressions. The estimates were compared with actual chewing forces recorded by intra-oral transducers. In all muscles except the balancing-side masseter, the activity/bite-force ratio was significantly higher in chewing than in isometric biting. The actual mean chewing force amounted to 220 N, while EMG-based estimates ranged from 273 to 475 N, depending on the muscle used for estimation. The results indicate that different activity/force characteristics in dynamic and isometric biting can cause overestimation when chewing force is predicted from masticatory EMGs.
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Ibraheem, Marwa Qasim. "Prediction of Cutting Force in Turning Process by Using Artificial Neural Network." Al-Khwarizmi Engineering Journal 16, no. 2 (June 1, 2020): 34–46. http://dx.doi.org/10.22153/kej.2020.04.002.
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Cutting forces are important factors for determining machine serviceability and product quality. Factors such as speed feed, depth of cut and tool noise radius affect on surface roughness and cutting forces in turning operation. The artificial neural network model was used to predict cutting forces with related to inputs including cutting speed (m/min), feed rate (mm/rev), depth of cut (mm) and work piece hardness (Map). The outputs of the ANN model are the machined cutting force parameters, the neural network showed that all (outputs) of all components of the processing force cutting force FT (N), feed force FA (N) and radial force FR (N) perfect accordance with the experimental data. Twenty-five samples of experimental data were used, including nineteen to train the network. Moreover six other experimental tests were implemented to test the network. The study concludes that ANN was a dependable and precise method for predicting machining parameters in CNC turning operation.
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Soon, Chin Fhong, Mohamad A. Genedy, Mansour Youseffi, and Morgan C. T. Denyer. "Cell Traction Force Mapping in MG63 and HaCaTs." Advanced Materials Research 832 (November 2013): 39–44. http://dx.doi.org/10.4028/www.scientific.net/amr.832.39.
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The ability of a cell to adhere and transmit traction forces to a surface reveals the cytoskeleton integrity of a cell. Shear sensitive liquid crystals were discovered with new function in sensing cell traction force recently. This liquid crystal has been previously shown to be non-toxic, linear viscoelastic and sensitive to localized exerted forces. This paper reports the possibility of extending the application of the proposed liquid crystal based cell force sensor in sensing traction forces of osteoblast-like (MG-63) and human keratinocyte (HaCaT) cell lines exerted to the liquid crystal sensor. Incorporated with cell force measurement software, force distributions of both cell types were represented in force maps. For these lowly contractile cells, chondrocytes expressed regular forces (10 – 90 nN, N = 200) around the circular cell body whereas HaCaT projected forces (0 – 200 nN, N = 200) around the perimeter of poly-hedral shaped body. These forces are associated with the organisation of the focal adhesion expressions and stiffness of the LC substrate. From the results, liquid crystal based cell force sensor system is shown to be feasible in detecting forces of both MG63 and HaCaT.
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Dwivedi, Anil M., S. Krimm, and Sheella Mierson. "Vibrational force field and normal mode analysis of N,N-dimethylacetamide." Spectrochimica Acta Part A: Molecular Spectroscopy 45, no. 2 (January 1989): 271–79. http://dx.doi.org/10.1016/0584-8539(89)80133-3.
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Qian, Jian Qing, Ji Ping Chen, and Hai Fan Qian. "The Influence of N Values on Sheet Metal Deep Drawing Based on Different Blank Holder Forces." Advanced Materials Research 418-420 (December 2011): 1364–67. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.1364.
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The influence of hardening index n value at different holding forces on LDR of cylinder cup was simulated by the finite element software PAM-STAMP 2G. The results showed that the limit drawing ratio of the sheet metal decreased with the increase of the blank holder force. There was little influence of hardening index n value on the limit drawing ratio at smaller blank holder force. The influence of hardening index n value on the limit drawing ratio increased with the increase of the blank holder force. The hardening index n value could be increased to increase the limit drawing ratio when the blank holder force is large.
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Edsfeldt, S., D. Rempel, K. Kursa, E. Diao, and L. Lattanza. "In vivo flexor tendon forces generated during different rehabilitation exercises." Journal of Hand Surgery (European Volume) 40, no. 7 (June 26, 2015): 705–10. http://dx.doi.org/10.1177/1753193415591491.
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We measured in vivo forces in the flexor digitorum profundus and the flexor digitorum superficialis tendons during commonly used rehabilitation manoeuvres after flexor tendon repair by placing a buckle force transducer on the tendons of the index finger in the carpal canal during open carpal tunnel release of 12 patients. We compared peak forces for each manoeuvre with the reported strength of a flexor tendon repair. Median flexor digitorum profundus force (24 N) during isolated flexor digitorum profundus flexion and median flexor digitorum superficialis force (13 N) during isolated flexor digitorum superficialis flexion were significantly higher than during the other manoeuvres. Significantly higher median forces were observed in the flexor digitorum superficialis with the wrist at 30° flexion (6 N) compared with the neutral wrist position (5 N). Median flexor digitorum profundus forces were significantly higher during active finger flexion (6 N) compared with place and hold (3 N). Place and hold and active finger flexion with the wrist in the neutral position or tenodesis generated the lowest forces; isolated flexion of these tendons generated higher forces along the flexor tendons. Level of evidence: III (controlled trial without randomization)
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Frederico, T., I. D. Goldman, and Sadhan K. Adhikari. "Possibility of new information about the N-N force in N-d polarization observables." Physical Review C 37, no. 3 (March 1, 1988): 949–53. http://dx.doi.org/10.1103/physrevc.37.949.
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Kinoshita, Hiroshi, Lars Bäckström, J. Randall Flanagan, and Roland S. Johansson. "Tangential Torque Effects on the Control of Grip Forces When Holding Objects With a Precision Grip." Journal of Neurophysiology 78, no. 3 (September 1, 1997): 1619–30. http://dx.doi.org/10.1152/jn.1997.78.3.1619.
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Kinoshita, Hiroshi, Lars Bäckström, J. Randall Flanagan, and Roland S. Johansson. Tangential torque effects on the control of grip forces when holding objects with a precision grip. J. Neurophysiol. 78: 1619–1630, 1997. When we manipulate small objects, our fingertips are generally subjected to tangential torques about the axis normal to the grasp surface in addition to linear forces tangential to the grasp surface. Tangential torques can arise because the normal force is distributed across the contact area rather than focused at a point. We investigated the effects of tangential torques and tangential forces on the minimum normal forces required to prevent slips (slip force) and on the normal forces actually employed by subjects to hold an object in a stationary position with the use of the tips of the index finger and thumb. By changing the location of the object's center of gravity in relation to the grasp surface, various levels of tangential torque (0–50 N⋅mm) were created while the subject counteracted object rotation. Tangential force (0–3.4 N) was varied by changing the weight of the object. The flat grasp surfaces were covered with rayon, suede, or sandpaper, providing differences in friction in relation to the skin. Under zero tangential force, both the employed normal force and the slip force increased in proportion to tangential torque with a slope that reflected the current frictional condition. Likewise, with pure tangential force, these forces increased in proportion to tangential force. The effects of combined tangential torques and tangential forces on the slip force were primarily additive, but there was a significant interaction of these variables. Specifically, the increase in slip force for a given increment in torque decreases as a function of tangential force. A mathematical model was developed that successfully predicted slip force from tangential torque, tangential force, and an estimate of coefficient of static friction in the digit-surface interface. The effects of combined tangential torques and forces on the employed normal force showed the same pattern as the effects on the slip force. The safety margin against frictional slips, measured as the difference between the employed normal force and the slip force, was relatively small and constant across all tangential force and torque levels except at small torques (<10 N⋅mm). There was no difference in safety margin between the digits. In conclusion, tangential torque strongly influences the normal force required for grasp stability. When controlling normal force, people take into account, in a precise fashion, the slip force reflecting both tangential force and tangential torque and their interaction as well as the current frictional condition in the object-digit interface.
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Jiang, Yan, Lili Yue, Boshen Yan, Xi Liu, Xiaofei Yang, Guoan Tai, and Juan Song. "Electric Control of Friction on Silicon Studied by Atomic Force Microscope." Nano 10, no. 03 (April 2015): 1550038. http://dx.doi.org/10.1142/s1793292015500381.
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We investigated friction on an n-type silicon surface using an atomic force microscope when a bias voltage was applied to the sample. Friction forces on the same track line were measured before and after the bias voltages were applied and it was found that the friction forces in n-type silicon can be tuned reversibly with the bias voltage. The dependence of adhesion forces between the silicon nitride tip and Si sample on the bias voltages approximately follows a parabolic law due to electrostatic force, which results in a significant increase in the friction force at an applied electric field.
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Hichert, Mona, and Dick H. Plettenburg. "Ipsilateral Scapular Cutaneous Anchor System: An alternative for the harness in body-powered upper-limb prostheses." Prosthetics and Orthotics International 42, no. 1 (March 20, 2017): 101–6. http://dx.doi.org/10.1177/0309364617691624.
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Background: Body-powered prosthesis users frequently complain about the poor cosmesis and comfort of the traditional shoulder harness. The Ipsilateral Scapular Cutaneous Anchor System offers an alternative, but it remains unclear to what extent it affects the perception and control of cable operation forces compared to the traditional shoulder harness. Objective: To compare cable force perception and control with the figure-of-nine harness versus the Ipsilateral Scapular Cutaneous Anchor System and to investigate force perception and control at different force levels. Study design: Experimental trial. Methods: Ten male able-bodied subjects completed a cable force reproduction task at four force levels in the range of 10–40 N using the figure-of-nine harness and the Anchor System. Perception and control of cable operating forces were quantified by the force reproduction error and the force variability. Results: In terms of force reproduction error and force variability, the subjects did not behave differently when using the two systems. The smallest force reproduction error and force variability were found at the smallest target force level of 10 N. Conclusion: The Anchor System performs no differently than the traditional figure-of-nine harness in terms of force perception and control, making it a viable alternative. Furthermore, users perceive and control low operation forces better than high forces. Clinical relevance The Ipsilateral Scapular Cutaneous Anchor System offers an alternative for the traditional harness in terms of cable operation force perception and control and should therefore be considered for clinical use. Low cable operation forces increase the perception and control abilities of users.
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Kiselev, M. G., V. L. Gabets, S. G. Monich, and V. A. Petrov. "METHODOLOGY AND HARDWARE FOR DETERMINING THE FORCE REQUIRED TO MOVE THE PLUNGER ROD OF A DISPOSABLE SYRINGE." Doklady BGUIR 18, no. 2 (March 31, 2020): 80–88. http://dx.doi.org/10.35596/1729-7648-2020-18-2-80-88.
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The purpose of the article is to describe the methodology and hardware for determining the force required for the movement of the plunger rod of a single-use syringe. The measurement method is used to obtain new experimental data. We first-ever obtained the oscillograms of force variation required to move the plunger rod of test syringes and found that, compared to a two-component, three-component syringe is characterized by significantly smaller values of the effort required for the plunger rod to move. So, when it moves without using water, the F value at the beginning of the suction stage is 1.5 times less than that of a two-component syringe and 2.4 times less at the extrusion stage. The use of water increases the force required to move the rod-piston of the test syringes. Thus, for a two-component syringe the force at the suction stage without using water was 4.5 N and 5.5 N – at the extrusion stage, and with the use of water, the values of these forces, respectively, increased to 6.5 and 6 N. For a three-component syringe without water, the plunger rod displacement force at the suction stage was 2.9 N and at the extrusion stage – 2.3 N, and with water the values of these forces increased to 3.7 and 2.9 N, respectively. The device developed makes it possible to conduct comprehensive studies of the effect of the type of syringe, its capacity, the speed of movement of the plunger rod, the duration of the stop between liquid suction and extrusion stages and other parameters on the amount of forces required to move the plunger rod of the syringe. This will allow you to justify the conditions and the normalized value of the force (or forces) required for the movement of the plunger rod when testing syringes by this indicator.
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Pałubicki, Bartosz. "Cutting Forces in Peripheral Up-Milling of Particleboard." Materials 14, no. 9 (April 25, 2021): 2208. http://dx.doi.org/10.3390/ma14092208.
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An analysis of forces acting in the peripheral up-milling of particleboard is presented. First, a novel method of high-frequency piezoelectric force signal treatment is proposed and used to separate the original force signal from the vibrations of the previous cutting iteration. This allows for the analysis of single chip cutting force courses during industrial CNC (Computer Numerical Control) milling. The acting forces are compared with the theoretical, instantaneous, uncut chip thickness. The results show that, for a range of 40–60 m/s, the higher the cutting speed used, the higher the resultant and principal cutting forces. The method of cutting thrust force used was similar to that observed in solid wood milling, i.e., first using a pushing action, followed by a pulling action. The obtained average specific principal cutting forces for particleboard peripheral up-milling are equal to 32.0 N/mm2 for slow and 37.6 N/mm2 for fast milling. The specific cutting thrust force decreases with the increase in instantaneous uncut chip thickness.
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Hardin, E. C., A. Su, and A. J. van den Bogert. "Pre-Impact Lower Extremity Posture and Brake Pedal Force Predict Foot and Ankle Forces During an Automobile Collision." Journal of Biomechanical Engineering 126, no. 6 (December 1, 2004): 770–78. http://dx.doi.org/10.1115/1.1824122.
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Background: The purpose of this study was to determine how a driver’s foot and ankle forces during a frontal vehicle collision depend on initial lower extremity posture and brake pedal force. Method of Approach: A 2D musculoskeletal model with seven segments and six right-side muscle groups was used. A simulation of a three-second braking task found 3647 sets of muscle activation levels that resulted in stable braking postures with realistic pedal force. These activation patterns were then used in impact simulations where vehicle deceleration was applied and driver movements and foot and ankle forces were simulated. Peak rearfoot ground reaction force FRF, peak Achilles tendon force FAT, peak calcaneal force FCF and peak ankle joint force FAJ were calculated. Results: Peak forces during the impact simulation were 476±687NFRF, 2934±944 N FCF and 2449±918 N FAJ. Many simulations resulted in force levels that could cause fractures. Multivariate quadratic regression determined that the pre-impact brake pedal force (PF), knee angle (KA) and heel distance (HD) explained 72% of the variance in peak FRF, 62% in peak FCF and 73% in peak FAJ. Conclusions: Foot and ankle forces during a collision depend on initial posture and pedal force. Braking postures with increased knee flexion, while keeping the seat position fixed, are associated with higher foot and ankle forces during a collision.
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Martelli, Saulo, Daniela Calvetti, Erkki Somersalo, and Marco Viceconti. "Stochastic modelling of muscle recruitment during activity." Interface Focus 5, no. 2 (April 6, 2015): 20140094. http://dx.doi.org/10.1098/rsfs.2014.0094.
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Muscle forces can be selected from a space of muscle recruitment strategies that produce stable motion and variable muscle and joint forces. However, current optimization methods provide only a single muscle recruitment strategy. We modelled the spectrum of muscle recruitment strategies while walking. The equilibrium equations at the joints, muscle constraints, static optimization solutions and 15-channel electromyography (EMG) recordings for seven walking cycles were taken from earlier studies. The spectrum of muscle forces was calculated using Bayesian statistics and Markov chain Monte Carlo (MCMC) methods, whereas EMG-driven muscle forces were calculated using EMG-driven modelling. We calculated the differences between the spectrum and EMG-driven muscle force for 1–15 input EMGs, and we identified the muscle strategy that best matched the recorded EMG pattern. The best-fit strategy, static optimization solution and EMG-driven force data were compared using correlation analysis. Possible and plausible muscle forces were defined as within physiological boundaries and within EMG boundaries. Possible muscle and joint forces were calculated by constraining the muscle forces between zero and the peak muscle force. Plausible muscle forces were constrained within six selected EMG boundaries. The spectrum to EMG-driven force difference increased from 40 to 108 N for 1–15 EMG inputs. The best-fit muscle strategy better described the EMG-driven pattern ( R 2 = 0.94; RMSE = 19 N) than the static optimization solution ( R 2 = 0.38; RMSE = 61 N). Possible forces for 27 of 34 muscles varied between zero and the peak muscle force, inducing a peak hip force of 11.3 body-weights. Plausible muscle forces closely matched the selected EMG patterns; no effect of the EMG constraint was observed on the remaining muscle force ranges. The model can be used to study alternative muscle recruitment strategies in both physiological and pathophysiological neuromotor conditions.
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Ma, Richard, Michael Schär, Tina Chen, Marco Sisto, Joseph Nguyen, Clifford Voigt, Xiang-Hua Deng, and Scott A. Rodeo. "Effect of Dynamic Changes in Anterior Cruciate Ligament In Situ Graft Force on the Biological Healing Response of the Graft-Tunnel Interface." American Journal of Sports Medicine 46, no. 4 (January 3, 2018): 915–23. http://dx.doi.org/10.1177/0363546517745624.
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Background: Anterior cruciate ligament (ACL) grafts that are placed for reconstruction are subject to complex forces. Current “anatomic” ACL reconstruction techniques may result in greater in situ graft forces. The biological effect of changing magnitudes of ACL graft force on graft-tunnel osseointegration is not well understood. Purpose: The research objective is to determine how mechanical force on the ACL graft during knee motion affects tendon healing in the tunnel. Study Design: Controlled laboratory study. Methods: Male rats (N = 120) underwent unilateral ACL reconstruction with a soft tissue flexor tendon autograft. ACL graft force was modulated by different femoral tunnel positions at the time of surgery to create different graft force patterns with knee motion. External fixators were used to eliminate graft load during cage activity. A custom knee flexion device was used to deliver graft load through controlled daily knee motion. Graft-tunnel healing was then assessed via biomechanical, micro–computed tomography, and histological analyses. Results: ACL graft-tunnel healing was sensitive to dynamic changes in graft forces with postoperative knee motion. High ACL graft force with joint motion resulted in early inferior ACL graft load to failure as compared with knees that had low-force ACL grafts and joint motion and knees that were immobilized (mean ± SD: 5.50 ± 2.30 N vs 9.91 ± 3.54 N [ P = .013] and 10.90 ± 2.8 N [ P = .001], respectively). Greater femoral bone volume fraction was seen in immobilized knees and knees with low-force ACL grafts when compared with high-force ACL grafts at 3 and 6 weeks. Conclusion: The authors were able to demonstrate that ACL graft-tunnel incorporation is sensitive to dynamic changes in ACL graft force with joint motion. Early high forces on the ACL graft appear to impair graft-tunnel osseointegration. Clinical Relevance: Current “anatomic” techniques of ACL reconstruction may result in greater graft excursion and force with knee motion. Our results suggest that the postoperative rehabilitation regimen may need to be modified during the early phase of healing to protect the reconstruction.
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Shintcovsk, Ricardo Lima, Roberto Soares da Silva Júnior, Larry White, Lidia Parsekian Martins, and Renato Parsekian Martins. "Evaluation of the load system produced by a single intrusion bend in a maxillary lateral incisor bracket with different alloys." Angle Orthodontist 88, no. 5 (May 15, 2018): 611–16. http://dx.doi.org/10.2319/081717-556.1.
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ABSTRACT Objectives: To evaluate if a 0.5-mm vertical bend applied on an incisor bracket produces movements in other planes and if different wires influence these effects. Materials and Methods: An acrylic model of a treated patient with brackets passively bonded was attached to an Orthodontic Force Tester, and a load cell was attached to the left lateral incisor. Thirty 0.019 × 0.025-inch archwires were divided into three groups according to their alloy: SS (stainless steel), B-Ti (beta-titanium), and MF (beta-titanium wire coated with nickel-titanium). Step-bends of 0.5 mm high were placed on the lateral incisor bracket using a universal plier, and the forces and moments in three dimensions were statistically analyzed by analysis of variance and Tukey post hoc test. Results: SS produced a larger force (3.4 N) than the B-Ti (1.41 N) and the MF (0.53 N; P < .001). Lingual forces were produced by the SS (0.82 N) and B-Ti (0.31 N) groups, while in the MF group, the force was insignificant. SS produced a mesial force of 0.24 N, while the B-Ti force was insignificant and MF produced 0.09 N. Groups produced different crown-distal tipping moments (SS = 31.48 N-mm, B-Ti = 11.7 N-mm, and MF = 4.55 N-mm) and different crown-buccal tipping moments. SS produced larger moments (3.63 N-mm) than B-Ti (1.02 N-mm) and MF (0.36 N-mm) wires. A mesial-out rotational moment was observed in all groups (SS = 7.17 N-mm, B-Ti = 3.46 N-mm, and MF = 0.86 N-mm). Conclusions: A 0.5-mm intrusion bend produced lingual and mesial side effects. In addition to the distal and buccal crown-tipping moments, there was a mesial-out moment. Compared with SS, B-Ti and MF wires produced lower forces. These more flexible wires showed side effects with lesser intensity.
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Goto, Tadahiro, Yasuaki Koyama, Takashiro Kondo, Yusuke Tsugawa, and Kohei Hasegawa. "A comparison of the force applied on oral structures during intubation attempts between the Pentax-AWS airwayscope and the Macintosh laryngoscope: a high-fidelity simulator-based study." BMJ Open 4, no. 10 (October 2014): e006416. http://dx.doi.org/10.1136/bmjopen-2014-006416.
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ObjectiveWe sought to determine whether the use of Pentax-AWS Airwayscope (AWS) applied less force on oral structures during intubation attempts than a conventional direct laryngoscope (DL).DesignProspective cross-over study.ParticipantsA total of 37 physicians (9 transitional-year residents, 20 emergency medicine residents and 8 emergency physicians) were enrolled.InterventionsWe used four simulation scenarios according to the difficulty of intubation and devices and used a high-fidelity simulator to quantify the forces applied on the oral structures.Outcome measuresPrimary outcomes were the maximum force applied on the maxillary incisors and tongue. Other outcomes of interest were time to intubation and glottic view during intubation attempts.ResultsThe maximum force applied on the maxillary incisors in the normal airway scenario was higher with the use of AWS than that with DL (107 newton (N) vs 77 N, p=0.02). By contrast, the force in the difficult airway scenario was significantly lower with the use of AWS than that of the DL (89 N vs 183 N, p<0.01). Likewise, the force applied on the tongue was significantly lower with the use of AWS than the use of DL in both airway scenarios (11 N vs 27 N, p<0.001 in the normal airway scenario; 12 N vs 40 N, p<0.01 in the difficult airway scenario).ConclusionsThe use of AWS during intubation attempts was associated with decreased forces applied to oral structures in the simulated difficult airway scenario.
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Joice, Paul, Peter D. Ross, Dong Wang, Eric W. Abel, and Paul S. White. "Measurement of Osteotomy Force during Endoscopic Sinus Surgery." Allergy & Rhinology 3, no. 2 (January 2012): ar.2012.3.0032. http://dx.doi.org/10.2500/ar.2012.3.0032.
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Greater understanding of the surgeon's task and skills are required to improve surgical technique and the effectiveness of training. Currently, neither the objective measurement of osteotomy forces during endoscopic sinus surgery (ESS) nor the validity of the properties of cadaver materials, are well documented. Measurement was performed of peak axial osteotomy force during ESS. A comparison was made of results with previously published cadaver data to validate the force properties of cadaver models. A prospective, consecutive cohort of 25 patients was compared with data from 15 cadaver heads. A modified Storz sinus curette measured osteotomy force from uncinate, bulla ethmoidalis, and ground lamella. Independent variables were osteotomy site, age, gender, indication for surgery, and side. Corresponding cadaver data were analyzed for the independent variables of osteotomy site, side, and gender and then compared with the live patient data. Mean osteotomy force in live patients was 9.6 N (95% CI, 8.9–10.4 N). Mean osteotomy force in the cadaver heads was 6.4 N (95% CI, 5.7–7.0 N). Ethmoid osteotomy of live patients required 3.2 N (95% CI, 2.1–4.3 N) more force than the cadaver heads (p = 0.0001). This relationship was statistically significant at the bulla ethmoidalis (p = 0.002) and the ground lamella (p = 0.0001) but not at the uncinate (p = 0.068). Osteotomy in female live subjects required 1.6 N (95% CI, 0.1–3.1 N) more force than male live subjects (p = 0.03). Cadaver tissue may underestimate the mean osteotomy force required in osteotomy of living ethmoid sinus lamellae by a factor of 1.5 times. Caution may be required in extrapolating force estimates from cadaver tissue to those required in living patients.
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Sliwa, Agata, Marek Sroka, Ludwina Zukowska, Katarzyna Bloch, Petrica Vizureanu, and Andrei Victor Sandu. "Numerical Analysis of Strength Properties of Anatomical General Surgical Tweezers." Revista de Chimie 69, no. 1 (February 15, 2018): 187–90. http://dx.doi.org/10.37358/rc.18.1.6071.
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The purpose of the work was to perform a numerical analysis, with the FEM method, of anatomical tweezers loaded with the forces of 10 and 50 N. Tweezers consist of two arms connected permanently by welding and are used for holding tissues. ANSYS software was used for the simulation. The force of 10 N expresses the gripping force during correct handling of tweezers, whereas the force of 50 N simulates a very high load on tweezers. Distribution of stresses, deformations and displacements created during tweezers� work was obtained as a result of the simulations conducted.
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Buśko, Krzysztof, and Pantelis T. Nikolaidis. "Biomechanical characteristics of Taekwondo athletes: kicks and punches vs. laboratory tests." Biomedical Human Kinetics 10, no. 1 (June 21, 2018): 81–88. http://dx.doi.org/10.1515/bhk-2018-0013.
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Summary Study aim: The aim of the study was to examine biomechanical characteristics of taekwondo athletes comparing kicks and punches with laboratory tests of muscle strength and power. Material and methods: Six male taekwondo athletes participated in this study. Measurements of maximal punching with the rear hand (hook and straight punches) and kicking (Apdolio and Dwit Chagi) force were performed on a boxing dynamometer. Also, the following laboratory tests were performed: jump height and power output in counter movement jump (CMJ) and spike jump (SPJ), muscle strength for 10 muscle groups and force-velocity (F-v) relationship. Results: Mean maximal straight and hook punching forces were 1659.2 ± 254.2 N and 1843.8 ± 453.3 N, respectively. Maximal Apdolio rear leg, Apdolio lead leg and Dwit Chagi rear leg kicking forces were 3541.3 ± 1130.3 N, 3205.3 ± 965.1 N and 3568.0 ± 1306.0 N, respectively. The heights of jumps were 0.501 ± 0.040 m (CMJ) and 0.554 ± 0.034 m (SPJ). A strong correlation between the maximal force of a punch and maximal joint torques was observed. Conclusions: The values of kicking forces developed in a simulated fight were lower than the forces developed in the test of individual kicks. Strong relationships were observed between leg power developed in the SPJ and force of individual Apdolio kicks performed with the lead (r = 0.87, p < 0.05) and rear leg (r = 0.74). Based on these findings, it was concluded that maximal joint torques and height of the SPJ could be used as a proxy of kicking force.
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Viji Babu, Prem Kumar, Ursula Mirastschijski, Ganzanfer Belge, and Manfred Radmacher. "Homophilic and heterophilic cadherin bond rupture forces in homo- or hetero-cellular systems measured by AFM-based single-cell force spectroscopy." European Biophysics Journal 50, no. 3-4 (April 20, 2021): 543–59. http://dx.doi.org/10.1007/s00249-021-01536-2.
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AbstractCadherins enable intercellular adherens junctions to withstand tensile forces in tissues, e.g. generated by intracellular actomyosin contraction. In-vitro single molecule force spectroscopy experiments can reveal cadherin–cadherin extracellular region binding dynamics such as bond formation and strength. However, characterization of cadherin-presenting cell homophilic and heterophilic binding in the proteins’ native conformational and functional states in living cells has rarely been done. Here, we used atomic force microscopy (AFM) based single-cell force spectroscopy (SCFS) to measure rupture forces of homophilic and heterophilic bond formation of N- (neural), OB- (osteoblast) and E- (epithelial) cadherins in living fibroblast and epithelial cells in homo- and hetero-cellular arrangements, i.e., between cells and cadherins of the same and different types. In addition, we used indirect immunofluorescence labelling to study and correlate the expression of these cadherins in intercellular adherens junctions. We showed that N/N and E/E-cadherin homophilic binding events are stronger than N/OB heterophilic binding events. Disassembly of intracellular actin filaments affects the cadherin bond rupture forces suggesting a contribution of actin filaments in cadherin extracellular binding. Inactivation of myosin did not affect the cadherin rupture force in both homo- and hetero-cellular arrangements, but particularly strengthened the N/OB heterophilic bond and reinforced the other cadherins’ homophilic bonds.
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Hashizume, Satoru, and Toshio Yanagiya. "A Forefoot Strike Requires the Highest Forces Applied to the Foot Among Foot Strike Patterns." Sports Medicine International Open 01, no. 02 (February 2017): E37—E42. http://dx.doi.org/10.1055/s-0042-122017.
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AbstractGround reaction force is often used to predict the potential risk of injuries but may not coincide with the forces applied to commonly injured regions of the foot. This study examined the forces applied to the foot, and the associated moment arms made by three foot strike patterns. 10 male runners ran barefoot along a runway at 3.3 m/s using forefoot, midfoot, and rearfoot strikes. The Achilles tendon and ground reaction force moment arms represented the shortest distance between the ankle joint axis and the line of action of each force. The Achilles tendon and joint reaction forces were calculated by solving equations of foot motion. The Achilles tendon and joint reaction forces were greatest for the forefoot strike (2 194 and 3 137 N), followed by the midfoot strike (1 929 and 2 853 N), and the rearfoot strike (1 526 and 2 394 N). The ground reaction force moment arm was greater for the forefoot strike than for the other foot strikes, and was greater for the midfoot strike than for the rearfoot strike. Meanwhile, there were no differences in the Achilles tendon moment arm among all foot strikes. These differences were attributed mainly to differences in the ground reaction force moment arm among the three foot strike patterns.
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Abada, Abdellatif. "On the Skyrme model prediction for the N - N spin - orbit force." Journal of Physics G: Nuclear and Particle Physics 22, no. 5 (May 1, 1996): L57—L63. http://dx.doi.org/10.1088/0954-3899/22/5/001.
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Hartrumpf, Martin, Josephine Sterner, Filip Schroeter, Ralf-Uwe Kuehnel, Magdalena L. Laux, Christian Braun, and Johannes M. Albes. "Tourniquet fixing prior to knot tying reduces forces during aortic valve replacement: experimental results from 18 surgeons." Interactive CardioVascular and Thoracic Surgery 31, no. 4 (August 18, 2020): 446–53. http://dx.doi.org/10.1093/icvts/ivaa135.
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Abstract OBJECTIVES To increase the safety of aortic valve replacement, we developed the ‘Caput medusae’ method, where the prosthesis is prefixed with circumferential tourniquets prior to knot tying. We assumed that an even distribution of forces may help reduce tissue damage. To confirm this theoretically, we compared forces between knots and tourniquets. METHODS The experimental set-up included a device with movable acrylic plates, a mounted valve and a set of sutures. Traction forces were measured with a luggage scale. Two different tourniquets were compared individually and as bundles of 15. Force–path curves were generated. Knotting and tourniquet forces of 18 staff surgeons were then compared. Both modalities were measured 10 times on 2 days, resulting in 40 observations per surgeon, or 360 observations per modality. RESULTS Polyvinyl chloride tourniquets were stiffer than silicone, expressed by a 1.5- to 1.7-fold higher regression-line slope. Fifteen simultaneous tubes produced force increments 7.9–8.9 times higher than their single counterparts. Overall knotting force was 13.64 ± 5.76 vs tourniquet 1.08 ± 0.48 N. Male surgeons’ knotting forces were higher compared to female staff (14.76 ± 6.01 vs 10.73 ± 3.74 N; P < 0.001) while tourniquet forces did not differ (1.09 ± 0.47 vs 1.05 ± 0.49 N; P = 0.459). Dedicated valve surgeons (n = 10) tightened the tourniquets more strongly than inexperienced surgeons (1.20 ± 0.52 vs 0.94 ± 0.37 N; P < 0.001); knotting was similar. Multivariable analysis confirmed only valve experience as a predictor of tourniquet strength (experienced surgeons exerted higher force). CONCLUSIONS Tourniquets exert less force on the tissue than knots. When distributed over the circumference, they can reduce local tension and avoid potential paravalvular leakage. Complete or partial use of tourniquets may thus be an additional option to enhance surgical safety.
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Gao, Changhong, Dacheng Cong, Xiaochu Liu, Zhidong Yang, and Han Tao. "Hybrid position/force control of 6-dof hydraulic parallel manipulator using force and vision." Industrial Robot: An International Journal 43, no. 3 (May 16, 2016): 274–83. http://dx.doi.org/10.1108/ir-10-2015-0192.
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Purpose The purpose of this paper is to propose a hybrid position/force control scheme using force and vision for docking task of a six degrees of freedom (6-dof) hydraulic parallel manipulator (HPM). Design/methodology/approach The vision system consisted of a charge-coupled device (CCD) camera, and a laser distance sensor is used to provide globe relative position information. Also, a force plate is used to measure local contact forces. The proposed controller has an inner/outer loop structure. The inner loop takes charge of tracking command pose signals from outer loop as accurate as possible, while the outer loop generates the desired tracking trajectory according to force and vision feedback information to guarantee compliant docking. Several experiments have been performed to validate the performance of the proposed control scheme. Findings Experiment results show that the system has good performance of relative position tracking and compliant contact. In whole docking dynamic experiment, the amplitudes of contact forces are well controlled within 300 N, which can meet perfectly the requirement of the amplitude being not more than 1,000 N. Originality/value A hybrid position/force control scheme using force and vision is proposed to make a 6-dof HPM dock with a moving target object compliantly.
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Bullion, Conrad, and Hakan Gurocak. "Haptic Glove with MR Brakes for Distributed Finger Force Feedback." Presence: Teleoperators and Virtual Environments 18, no. 6 (December 1, 2009): 421–33. http://dx.doi.org/10.1162/pres.18.6.421.
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Most existing haptic gloves are complicated user interfaces with remotely located actuators. More compact and simpler haptic gloves would greatly increase our ability to interact with virtual worlds in a more natural way. This research explored the design of a compact force feedback glove using a new finger mechanism and magnetorheological (MR) brakes as passive actuators that oppose human finger motion. The mechanism allowed for a reduction of the number of actuators and application of distributed forces at the bottom surface of user's fingers when an object was grasped in a virtual environment. The MR brakes incorporated a serpentine flux path that led to a small brake with high torque output and the elimination of remote actuation. Force analysis of the mechanism, grasping force experiments, and virtual pick-and-place experiments were done. The glove reduced task completion time by 61% and could support up to 17 N fingertip force along with 11.9 N and 18.7 N middle and proximal digit forces.
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Mangamma, G., Sitaram Dash, and A. K. Tyagi. "Atomic Force Microscopy Investigations on N$^{+}$ Implanted TiN." IEEE Transactions on Nanotechnology 12, no. 6 (November 2013): 1007–11. http://dx.doi.org/10.1109/tnano.2013.2276409.
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Deng, Z. "Bistability of radiation force on N-atom system." Physics Letters A 117, no. 1 (July 1986): 27–30. http://dx.doi.org/10.1016/0375-9601(86)90230-6.
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Trulsson, M., and R. S. Johansson. "Encoding of amplitude and rate of forces applied to the teeth by human periodontal mechanoreceptive afferents." Journal of Neurophysiology 72, no. 4 (October 1, 1994): 1734–44. http://dx.doi.org/10.1152/jn.1994.72.4.1734.
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1. The encoding of force amplitude and force rate by human periodontal mechanoreceptive afferents was studied. Recordings were obtained from 19 single periodontal afferents in the inferior alveolar nerve with the use of tungsten microelectrodes. Loads consisting of a force increase (loading ramp), a phase of maintained force (static phase), and a force decrease (unloading ramp) were applied to the receptor bearing tooth, which was most often an incisor. The static forces applied ranged between 0.05 and 5 N, and the rate of force applied during the loading ramps ranged between 0.4 and 70 N/s. The forces were primarily applied in one of six directions (lingual, labial, mesial, distal, upward, or downward) that evoked the greatest discharge activity. 2. For each force application, the steady-state response was defined as the mean discharge rate during a 1-s period starting 0.5 s after the end of the loading ramp. Most afferents (15/19) exhibited a “hyperbolic” (viz., negatively accelerating) relationship between the amplitude of the stimulation force and the steady-state response, featuring a pronounced saturation tendency: the highest sensitivity to changes in static force was observed at force levels below 1 N. At higher force levels the sensitivity gradually diminished. Moreover, the dynamic sensitivity similarly decreased with increasing amplitude of static background force. For a subsample of afferents studied, comparable stimulus-response relationships were obtained in directions other than the most responsive one, but the discharge rates were lower. 3. In contrast to the response of most afferents, four (4/19) differed in that they consistently exhibited a nearly linear relationship between force amplitude and the steady-state response. Moreover, these afferents maintained their dynamic sensitivity as the amplitude of the background force was increased. 4. The steady-state response of all afferents was well described as a constant times F/ (F + c), where F represents the steady-state force, and c the force generating one-half the estimated maximum discharge rate that could be evoked by steady-state force stimulation. The c-parameter was on average 0.42 N (range 0.05–1.1 N) for the afferents exhibiting hyperbolic stimulus-response relationships. In contrast it ranged between 5 and 22 N for those exhibiting “nearly linear” relationships. A hypothetical model of the mechanics of the periodontal ligament supporting the F/(F + c) transform is proposed. 5. A general transfer function was developed to predict the instantaneous discharge rate of an individual afferent to arbitrary force profiles applied to the receptor bearing tooth.(ABSTRACT TRUNCATED AT 400 WORDS)
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Shannon, Zacariah K., Robert D. Vining, Maruti Ram Gudavalli, and Ron J. Boesch. "High-velocity, low-amplitude spinal manipulation training of prescribed forces and thrust duration: A pilot study." Journal of Chiropractic Education 34, no. 2 (April 5, 2019): 107–15. http://dx.doi.org/10.7899/jce-18-19.
Full textAbstract:
Objective High-velocity, low-amplitude spinal manipulation (HVLA-SM) may generate different therapeutic effects depending on force and duration characteristics. Variability among clinicians suggests training to target specific thrust duration and force levels is necessary to standardize dosing. This pilot study assessed an HVLA-SM training program using prescribed force and thrust characteristics. Methods Over 4 weeks, chiropractors and students at a chiropractic college delivered thoracic region HVLA-SM to a prone mannequin in six training sessions, each 30 minutes in duration. Force plates embedded in a treatment table were used to measure force over time. Training goals were 350 and 550 Newtons (N) for peak force and ≤150 ms for thrust duration. Verbal and visual feedback was provided after each training thrust. Assessments included 10 consecutive thrusts for each force target without feedback. Mixed-model regression was used to analyze assessments measured before, immediately following, and 1, 4, and 8 weeks after training. Results Error from peak force target, expressed as adjusted mean constant error (standard deviation), went from 107 N (127) at baseline, to 0.2 N (41) immediately after training, and 32 N (53) 8 weeks after training for the 350 N target, and 63 N (148), −6 N (58), and 9 N (87) for the 550 N target. Student median values met thrust duration target, but doctors' were >150 ms immediately after training. Conclusion After participation in an HVLA-SM training program, participants more accurately delivered two prescribed peak forces, but accuracy decreased 1 week afterwards. Future HVLA-SM training research should include follow-up of 1 week or more to assess skill retention.