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Search Results: 1 - 10 of 3242 matches for " Force "
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Centrifugal force: an appreciation  [PDF]
Kern E. Kenyon
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.37086
Abstract: The centrifugal force is used to increase the physical understanding of five examples taken from fluid dynamics, geophysics and the solar system, as well as four hypothetical orbital problems. Each example involves a balance of forces between the centrifugal force and one or two other forces, such as a pressure gradient and a component of the force of gravity. Among the examples chosen for examination are: the orbital motion of fluid particles in surface grav-ity waves, the boundary layer character of steady flow next to a curved rigid surface, the tornado, the rotating self-gravitating mass and the three-body problem.
Fabrication of two-dimensional periodic TiO2 pillar arrays by multi-beam laser interference lithography  [PDF]
Hiroyo Segawa, Hiroaki Misawa
Natural Science (NS) , 2009, DOI: 10.4236/ns.2009.13022
Abstract: Two-dimensional (2D) periodic TiO2 pillar arrays, applicable to photonic crystals and micro-channels, were fabricated by direct patterning of a TiO2-organic hybrid material by multi-beam laser interference lithography and calcination of hybrid patterns. 2D periodic pillars of a TiO2– organic hybrid material were prepared by irra-diation with the interference pattern of femto-second laser beams and removal of the non- irradiated portions. Two types of periodic pillar arrays, standing pillars and top-gathering pillars (four pillars gathered at the top), were obtained, depending on laser irradiation conditions. After calcination of TiO2–organic hybrid pillars, TiO2 pillar arrays were obtained without collapse.
Grip Force Using an Artificial Limb in a Congenital Amputee  [PDF]
Michael Trujillo, David I. Anderson, Marilyn Mitchell
Open Journal of Therapy and Rehabilitation (OJTR) , 2014, DOI: 10.4236/ojtr.2014.23014
Abstract: While much attention is being given in the application of advanced technologies to improve upper extremity prostheses, traditional body-powered prostheses still remain the most popular by people with an amputation. A body-powered prosthesis provides the user with a reasonable solution for limb loss given their simple design, lower maintenance and initial cost. The two major types of body-powered prosthesis use either voluntary opening or voluntary closing control of the terminal device (or prehensor) used for holding and manipulating objects. What differentiates these two types of control is the relationship between the muscular force used to apply tension on the cable attached to the prehensor and the force produced by the prehensor. It has been argued that the voluntary closing prosthesis has more optimal compatibility between the muscle force and grip force of the prehensor. As a result, it may provide an advantage to the user in tasks requiring the control of grip force. To determine the effectiveness of the voluntary closing and voluntary opening prosthesis, we asked a person with a congenital quadruple limb deficiency who is right hand dominant, and that uses voluntary opening prostheses to participate in a study investigating grip force control. The participant was required to match different target grip forces displayed on a computer monitor by manipulating the pressure exerted on a hand dynamometer using either a voluntary closing or voluntary opening prosthesis. The participant only had previous experience with a voluntary opening prosthesis. The results showed that in several measures, the participant performed better with the voluntary closing prosthesis. These results provided support for the muscular force-grip force compatibility hypothesis.
Reaction Force on Bubbles  [PDF]
Kern E. Kenyon
Natural Science (NS) , 2015, DOI: 10.4236/ns.2015.76034
Abstract: For large air bubbles rising steadily through still water, the upward reaction force on the spherical cap is calculated. When added to the buoyancy force on the roughly flat base of the bubble, the friction force at terminal velocity must be larger than it would be in the absence of the reaction force. Experimental data are used to estimate that the increase in the drag coefficient is expected to be about 4%.
Work in the Twenty-First Century and the Relevance of the Theory of Value  [PDF]
Fabiane S. Previtali, Cílson César Fagiani
Advances in Historical Studies (AHS) , 2017, DOI: 10.4236/ahs.2017.63007
Abstract: This article is a review about the book of Ricardo Antunes, The Meanings of Work: Essay on the Affirmation and Negation of Work that has been released in United States (Haymarker books, 2013), United Kingdom (Brill Books, 2013) and India (Akkar Books, 2013). The author, Ricardo Antunes, is an internationally renowned scholar in the field of sociology of work with several publications in Argentina, France, India, Italy, Portugal, Spain, United Kingdom and United States. The author, Ricardo Antunes, is an internationally renowned scholar in the field of sociology of work with several publications in Argentina, France, India, Italy, Portugal, Spain, United Kingdom and United States. In the book, originally published in 1999 by Boitempo Editorial, Sao Paulo?Brazil, after his research conducted in 1999 at the University of Sussex, under the supervision of István Mészáros, Antunes starts with rigorous analysis of the increasingly heterogeneous and multifaceted configuration of the working class as well as the overlaps between productive and unproductive, material and immaterial labour, to restore and complicate the thesis of the centrality of labour and its importance in human sociability.
Central Body Rotation Drives Orbital Revolutions  [PDF]
Paul Schroeder
Journal of Geoscience and Environment Protection (GEP) , 2018, DOI: 10.4236/gep.2018.612005
Abstract: Prior to the development of physics as a science it was sufficient to have motion that offsets a perpendicular gravitational force and continues forever. The total absence of any friction could be assigned to the “void” of space. But perpetual motion and empty space are now seen as fallacies. Continuous motion needs a driving force for impetus.
A Comparison of Pinch Force between Finger and Palm Grasp techniques in Laparoscopic Grasping  [PDF]
Susmitha Wils K, George Mathew, M. Manivannan, Suresh R Devasahayam
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.410B012
Abstract:

Laparoscopic surgery is a new abdominal surgical procedure which helps the patients in many ways like less hospital stay, faster recovery and reduced pain. The main disadvantage in this surgical procedure is the reduced haptic perception by the surgeons due to the usage of laparoscopic instrument to handle tissues which in turn cause damage of it as compared to an open surgery. The primary aim of this investigation was to compare the pinch force applied during two different methods of laparoscopic grasping: Finger and Palm grasp. A low cost force sensing resistor tailor made for the grasper tip was designed and fabricated for quantifying the grasper tip force in the study. The results indicate more pinch force was applied during palm grasp as compared to finger grasp so as to prevent the slippage of the tissues from the jaws of the laparoscopic graspers.

The Use of Light Diffracted from Grating Etched onto the Backside Surface of an Atomic Force Microscope Cantilever Increases the Force Sensitivity  [PDF]
Sergey K. Sekatskii, Mounir Mensi, Andrey G. Mikhaylov, Giovanni Dietler
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2013, DOI: 10.4236/jsemat.2013.34A1004
Abstract:

A reflecting diffraction grating has been etched onto the backside of a standard cantilever for atomic force microscopy, and the diffracted light has been used to monitor the angular position of the cantilever. It is shown experimentally that for small angles of incidence and for large reflection angles, the force sensitivity can be improved by few times when an appropriate detection scheme based on the position sensitive (duolateral) detector is used. The first demonstration was performed with a one micron period amplitude diffraction grating onto the backside of an Al-coated cantilever etched by a focused ion beam milling for the experiments in air and an analogous 600 nm-period grating for the experiments in air and in water.

Recognition of Force Magnitude Applied to Pressure-Sensitive Conducting Rubber Sensors on the Basis of Frequency Table  [PDF]
Masato Ohmukai, Yasushi Kami
Journal of Sensor Technology (JST) , 2018, DOI: 10.4236/jst.2018.84007
Abstract: This study aims to develop a force sensor system with a pressure-sensitive conductive rubber (PSCR), which shows the decrease of electrical resistance when pressure is applied. The biggest obstacle of the sensor is a poor reproducibility in the characteristic between the force and the resistance of the PSCR, which derived from a hysteresis and time variant properties. In this paper, we propose one method for recognizing a magnitude of the force to the PSCR using frequency tables. The validity of the proposed method is confirmed on the basis of experimental results.
Design and research of measuring system of clamping force of hemostats  [PDF]
Huifang Wang, Shuyi Wang, Ying Zhou, Jie Tan
Journal of Biomedical Science and Engineering (JBiSE) , 2010, DOI: 10.4236/jbise.2010.39123
Abstract: Reliability of medical instruments such as hemostats is extremely important because these instruments are used in patients who are in critical condition. Clamping force of hemostats, as an important parameter of hemostats, should be detected. However, it could not be tested directly. In order to test it, a testing system has been put forward. The system is comprised of sensor, acquisition card, and three-way tap and so on. This system is controlled by a computer. The testing system has been proved to be effective in testing the clamping force of hemostats.
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