A fracture criterion for sheet metals subjected to draw-bending is investigated using the concept of the forming limit stress criterion. The test material used is a 1.0-mm-thick high- strength steel sheet with a tensi...
A fracture criterion for sheet metals subjected to draw-bending is investigated using the concept of the forming limit stress criterion. The test material used is a 1.0-mm-thick high- strength steel sheet with a tensile strength of 590MPa. The specimen undergoes bendingunbending under tension when passing over the die profile. The drawing speed was set to 5-100 mm • s-1. The magnitude of true stress σDB when a specimen fractured has been precisely determined. Moreover, multiaxial tube expansion tests of the test material are performed to measure the forming limit stress σPT of the test material under plane-strain tension. It is found that σDB is larger than σPT by 2.8-6.3%. Therefore, it is concluded that the forming limit stress criterion is effective as a fracture criterion in draw-bending.
The purpose of this study was to develop an educational system in order to visualize radiation interactions in the learner's forearm through the use of Augmented Reality (AR) technology. The interactions are calcu...
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The purpose of this study was to develop an educational system in order to visualize radiation interactions in the learner's forearm through the use of Augmented Reality (AR) technology. The interactions are calculated by PHITS simulation code and the particle trajectories or the energy depositions are overlaid on live images captured by a USB camera. The system used ARToolKit library to overlay the box and bone 3D CG objects on the learner's forearm. The objects are generated by using Metasequoia4. The program has four modes of operation, X-ray Tomography, Heavy Ion Therapy, PET Imaging, and BNCT. By selecting one, the learner can learn about interactions of photons, carbon ions, positrons, and neutrons, respectively. The bone objects are overlaid only in the X-ray Tomography mode. As a result, the learner can see a simulation of the different interactions caused by each of the four kinds of radiation inside the learner's own forearm as 640 pixel × 480 pixel composited images on a PC screen at just over 5 fps.
Flexible devices produced using organic materials have attracted the attention of many researchers. Important components of these flexible devices include transparent electrodes, which transmit visible light and posse...
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Flexible devices produced using organic materials have attracted the attention of many researchers. Important components of these flexible devices include transparent electrodes, which transmit visible light and possess conductivity. The present study improved the characteristics of a transparent conductive film that was made of poly(3, 4 ethylenedioxythiophene):poly(styrenesul-fonate) (PEDOT:PSS), an organic conductive material, and that had been prepared using ink-jet printing. To improve the resistance value and visible light transmittance of the film, the film substrate was first cleaned with ultraviolet/ozone treatment, and then the film was annealed after it was deposited on the substrate and dipped into a polar solvent. Consequently, the resistance value of the thin film decreased. However, the surface state of the film changed according to the treatment method and affected its visible light transmittance. Thus, the surface state of the film substrate, the annealing temperature after film deposition, and the dipping treatment with a polar solvent influenced the characteristics of a thin film.
This paper describes a magnetic tactile sensor with Indium antimonide (InSb) Hall elements that enables multifunctional tactile sensing devices to detect normal contact forces and temperature. InSb Hall elements are g...
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This paper presents an experimental exergy analysis of the solar thermal system in the Off-Grid Zero Emissions Building (OGZEB) at the Florida State University in efforts to identify components with major irreversibil...
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This paper presents an experimental exergy analysis of the solar thermal system in the Off-Grid Zero Emissions Building (OGZEB) at the Florida State University in efforts to identify components with major irreversibilities, i.e., exergy destruction. The solar thermal system comprises a series of flat-plate solar thermal collectors and 250-gal sensible thermal energy storage tank, and it is an essential constituent of the OGZEB heating system. In this study, exergy flow and destruction rates throughout the solar thermal system were evaluated using the experimental data obtained on two different days. According to the analysis, the greatest exergy destruction rate was observed in the solar thermal collector as expected, and its average exergetic efficiencies were 7.9% and 6.5% on each respective day. In the thermal energy storage tank, most of the exergy destruction was attributed to the mixing of hot water from the collector with the reservoir. This work serves as an initial step to the integrative thermodynamic optimization of the HVAC system in an off-grid residential building, where most energy is consumed for air-conditioning and heating.
Triboelectric energy harvesting is a promising energy harvesting technology which converts ambient mechanical energy into electrical energy using triboelectric and electrostatic coupling effects. In this paper, a cont...
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ISBN:
(纸本)9781467391085
Triboelectric energy harvesting is a promising energy harvesting technology which converts ambient mechanical energy into electrical energy using triboelectric and electrostatic coupling effects. In this paper, a contact-mode triboelectric energy harvesting device (TEHD) were qualitatively analyzed using a precision test rig, which accurately controlled the contact force and approach speed. From the governing equations of the contact-mode TEHD, we found factors which influence the performance of TEHD, and this was verified by experiments. The contact force affected to the amount of triboelectric charges, and short-circuit current. The approach speed of moving part did not affect the charges, but the short circuit current, output power, and optimal resistance.
This paper presents an image-based position measurement of underwater objects using a low-cost maritime mobile robot with a monocular camera. Visual recognition of distant underwater objects is possible in the water w...
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ISBN:
(纸本)9781479917631
This paper presents an image-based position measurement of underwater objects using a low-cost maritime mobile robot with a monocular camera. Visual recognition of distant underwater objects is possible in the water with high transparency, for example, in the coastal sea area of Okinawa prefecture, Japan. In this paper, we apply the proposed method to estimate the position of an old anchor that is at a deep of 30 [m] and is estimated to be hundreds-of-years-old in an archaeological site in Ishigaki Island. We explain the measurement principle of the proposed method and the developed system. Moreover, we describe the experiment conducted off the coast of Ishigaki Island and show the experimental results of the proposed method.
Link elasticity is commonly understood to be a detrimental side-effect of imperfect mechanical designs of robotic arms and comparable machinery. In contrast to this notion, this paper demonstrates a novel approach to ...
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Link elasticity is commonly understood to be a detrimental side-effect of imperfect mechanical designs of robotic arms and comparable machinery. In contrast to this notion, this paper demonstrates a novel approach to exploit intrinsic robot link compliance in order to estimate a priori unknown payload masses, measure and also control end effector forces. In this way, the intrinsic link elasticity can be seen as an enabler for new sensing and control capabilities instead of a purely detrimental effect.
The current research represents a first step towards developing a decentralized network of small autonomous, intelligent and inexpensive unmanned aerial vehicles (UAV), which could be used for a variety of scientific ...
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Quadruped animals have high agility and grace skills in the motion over natural environment. An important feature of such animals is their abilities in the selection of appropriate gait in the response to the terrain ...
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ISBN:
(纸本)9781467372350
Quadruped animals have high agility and grace skills in the motion over natural environment. An important feature of such animals is their abilities in the selection of appropriate gait in the response to the terrain irregularities and also the smooth transition between them in order to increase the stability or conserve the energy. In this paper, a Cartesian CPG-based controller for the gait generation and the transition between them will be developed. The proposed approach uses nonlinear coupled oscillators for generating rhythmic signals. These patterns can be modulated by a programmed excitation signal and proportionally changing the frequency, amplitude and the coupling parameters among oscillators. According to these variations, the step length, duration of swing and stance phases of all legs, relative phase between the legs and the sequence of leg lifting can be adjusted smoothly especially by the duration of gait transition. Then, trajectories of swing legs along the z- and x-axeis will be computed through the data obtained form the CPG controller. The reference ZMP path will be desgined on the basis of the footprints of legs. Then, the COG trajectories will be calculated with a preview servo controller. Finally, some simulations are conducted to verify the effectiveness of the proposed approach both in the gait generation and smooth gait transition for a quadruped robot.
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