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Ma, Chicheng, Dong Jing, Mingyu Shao, Hui Yu, and Zonghe Guo. "Dynamical analysis and control of rotatory manipulators with time varying mass loads." International Journal of Applied Electromagnetics and Mechanics 64, no. 1-4 (December 10, 2020): 307–14. http://dx.doi.org/10.3233/jae-209335.
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Manipulators are widely used in industrial fields as automation equipment and robotic structures. Besides moving objects, manipulators often work with variable payloads, and the residual vibration significantly affects the position accuracy of manipulators. This paper mainly investigates the dynamic characteristics of flexible manipulators with time varying mass payloads and active control of the residual vibration is carried out. Finite element method is utilized to construct the dynamical model, and responses of the system are calculated by Bathe’s method. The influence of the time varying mass is analyzed in details, including an increasing mass case and a decreasing mass case. Then active control of the residual vibration is given based on a PID controller. To improve the control effect, genetic algorithm (GA) is applied to tune the parameters of the PID controller. Simulations demonstrate that the time varying mass affects the residual vibration of the system remarkably. For a decreasing mass system, a nonstructural negative damping is induced and the residual vibration may be strengthened, while for an increasing mass system, a nonstructural positive damping is caused and the residual vibration may be attenuated. The comparison of the control methods demonstrates that the GA-PID controller results in a significant improvement in the vibration reduction.
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Loveikin, V. S., and D. A. Mischuk. "Synthesis of Optimal Dynamic Mode of Manipulator Boom Movement Mounted on Elastic Base." Science & Technique 18, no. 1 (February 12, 2019): 55–61. http://dx.doi.org/10.21122/2227-1031-2019-18-1-55-61.
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In order to increase reliability and accuracy of robot manipulators or other construction equipment used for lifting operations an optimum dynamic mode for moving its boom system has been calculated in the paper. Results of the research have made it possible to construct a mathematical model for manipulator movement and obtain kinematic characteristics of the optimum dynamic mode. While determining the optimum dynamic motion mode, a criterion action has been used as an optimization criterion which represents a time integral with an integrand function expressing a dynamic component of manipulator drive power. Functions for changing kinematic characteristics of an manipulator boom have been calculated when it moves from one predetermined position to another one and which correspond to optimum dynamic mode of motion. Search for an optimum motion mode has been performed by minimizing the optimization criterion using the Euler–Poisson equations. In this case a generalized angle of rotation has been used which permits to relate movement of the boom and oscillations of its support part. As a linking component differential equations of system motion have been also applied, in which relationships between an oscillation angle, rigidity of a manipulator support, and its mass-geometric characteristics have been recorded. Results of the work can be useful for refinement and improvement of existing engineering methods for calculating the drive mechanisms of manipulators both at design/construction stages and in real operation modes, and the results can also be used while making design or improvement of similar executive mechanisms for construction equipment and robots.
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Yu, Guang, Jun Wu, Liping Wang, and Ying Gao. "Optimal Design of the Three-Degree-of-Freedom Parallel Manipulator in a Spray-Painting Equipment." Robotica 38, no. 6 (August 15, 2019): 1064–81. http://dx.doi.org/10.1017/s0263574719001255.
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SUMMARYSpray-painting equipments are important for the automatic spraying of long conical objects such as rocket fairing. This paper proposes a spray-painting equipment that consists of a feed worktable, a gantry frame and two serial–parallel mechanisms and investigates the optimal design of PRR–PRR parallel manipulator in serial–parallel mechanisms. Based on the kinematic model of the parallel manipulator, the conditioning performance, workspace and accuracy performance indices are defined. The dynamic model is derived using virtual work principle and dynamic evaluation index is defined. The conditioning performance, workspace, accuracy performance and dynamic performance are involved in multi-objective optimization design to determine the optimal geometrical parameters of the parallel manipulator. Furthermore, the geometrical parameters of the gantry frame are optimized. An example is given to show how to determine these parameters by taking a long object with conical surface as painted object.
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Sapietová, Alžbeta, Milan Sága, Ivan Kuric, and Štefan Václav. "Application of optimization algorithms for robot systems designing." International Journal of Advanced Robotic Systems 15, no. 1 (January 1, 2018): 172988141775415. http://dx.doi.org/10.1177/1729881417754152.
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The article presents the design and application of multi-software platform for solving kinematic synthesis of robot manipulator systems. It also presents a modern theoretical and application approach for modelling coupled mechanical systems, which include mobile robots. Due to high requirements for accuracy, efficiency, reliability and life cycle of technical equipment, several parameters ensuring optimal operating parameters need to be taken into account while dealing with the design. This is the reason for linking computational models to optimization algorithms that allows us to find the appropriate design parameters of analysed mechanical system, mechanisms, including mobile robots mostly by iterative way. The commercial working interface of the program ADAMS and open architecture of MATLAB programming language enable to share common data while dealing with model simulations in parallel. Both of them were used while designing and implementing the algorithm for the evaluation and optimization of parameters of technical equipment from the point of view of selected properties. While working on the task of the spatial mechanism of the six-member robot manipulator system, the algorithm solving the optimal parameters was created by applying the selected optimization techniques of the program MATLAB. Presented algorithm involves the creation of a map operating positions, which is further linked to the solution of the motion of interest points in the robotic system following a prescribed trajectory. This requires the geometry optimization of the selected members of the spatial robotic system in order to achieve such parameters so that the trajectory of the interest point of the output member would precisely match with the prescribed trajectory. It is important to note that these types of tasks create wider space for solving the assignments dealing with the development and application of technical equipment like mobile robots and their outputs that are linked to the needs of the practice.
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Wang, Chuan Jiang, Hao Jiang, Zhi Xian Zhang, Xiu Juan Sun, and Hong Cheng Liang. "Optimal Design for Clasp Arm of Small-Caliber Deep Well Rescue Robot." Applied Mechanics and Materials 220-223 (November 2012): 1254–57. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.1254.
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In view of the backward present rescue technique for small-caliber deep well, a kind of multifunctional rescue robot is designed, which is composed of a manipulator, a rescue mechanism, an anchorage mechanism, and a set of oxygen supply equipment. Owing to the different postures of the fallen person, the clasp arm of rescue mechanism needs to adjust itself to obtain an ideal rescue orientation in the narrow deep well. Furthermore, the clasp arm bears much more weight when it clasp and fix the fallen person. So, the optimal design about the clasp arm is studied. Meanwhile, based on SolidWorks software, the stress analyses for the designed clasp arm with loads have been finished. Results show that the performance of the optimal designed clasp arm is perfect, which make sure that the rescue robot is capable of carrying out complicated rescue.
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Nakazawa, Masaru. "Special Issue on Handling of Flexible Object." Journal of Robotics and Mechatronics 10, no. 3 (June 20, 1998): 167–69. http://dx.doi.org/10.20965/jrm.1998.p0167.
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It is difficult to introduce highly versatile automation using robots to handling deformable objects such as thread, cloth, wire, long beams, and thin plates in plant production processes, compared to the handling of rigid objects. Office equipment handles deformable objects such as paper and plastic. Problems unique to these objects is caused by speeding up such equipment and demand for upgrading its accuracy. In agriculture and medical care, automatic, intelligent handling of deformable objects such as fruit and animals has long been desired and practical systems sought. Deformable objects whose handling should be versatiley and accurately automated are classified into two groups based on handling: (A) Flexible, mostly thin, fine objects capable of elastic deformation (B) Soft objects easily crushed, such as soft fruits or animals The problem in handling the first group is controlling object deformation of an infinite degree of freedom with a finite number of manipulated variables. In contrast, a significant problem in handling the second group is often how to handle them without exerting excessive stress and how to handle them safely and reliably. The handling of these two groups differ greatly in mechanics and control theory, and this special issue focuses on the first group — flexible objects — mechanical collection and transport studies, control, and software. Recent studies on their handling are classified into four groups for convenience based on handled objects and types of handling task: (a) Control of deformation, internal force, and vibration or path planning of flexible objects (mainly thin plates and beams) using single or multiple manipulators. (b) Task understanding in insertion of elastic into rigid parts and vice versa, and the study of human skills to help robots accomplish these task. (c) Approaches on improved accuracy, intelligent control, and vibration damping in handling and transfer of sheets and strings with low flexural rigidity, represented by paper or wire. (d) Strategies for grasping and unfolding sheets such as cloth whose flexural rigidity is almost nil. For (a), studies are active on deformation control by two robot hands attempting to grasp cloth. 1-3) In the automobile industry, so-called flexible fixtureless assembly systems are advancing in which two robots process or assemble parts in mid-air without a fixed table to reduce lead time and cost. These systems are mostly developed assuming handled parts are rigid. Nguyen et al. work assuming parts such as sheet metal whose deformation must be taken into consideration.1) Nakagaki et al. propose form estimation that considers even plastic deformation in wire handling by robots, in connection with the development of robots for electric wire installation.4) Many studies cover flexible wire as elastic beams,3-9) but comparatively few focus on bending deformation of thin plates. This special edition includes a paper by Kosuge et al. on thin-plate deformation control. Vibration control of grasped objects becomes important as speed increases. Matsuno kindly contributed his paper on optimum path planning in elastic plate handling. In controlling the deformation of elastic bodies, the mechanics of objects handled is often unknown. This special issue features a paper by Kojima et al. on an approach to this problem by adaptive feed-forward control. For (b), we consider three cases: (1) A cylindrical rigid body inserted into a hole on an elastic plate. (2) An elastic bar inserted into a hole on a rigid body. (3) A tubular elastic body put on a cylindrical rigid body. This special issue carries papers on these problems by Brata et al., Matsuno et al., and Hirai. For (2), a paper by Nakagaki et al.10) covers electric wire installation. For (3), the paper by Shima et al.11) covers insertion of a rigid axis into an elastic hose. Robot skill acquisition is an important issue in robotics in general, and the above papers should prove highly interesting and information because they treat studies by comparing robot and human skills in accomplishing work and acquiring concrete skills knowledge. For (c), attempts are made to theoretically analyze sheet handling mechanisms and control developed based on trial and error, and to structure design theory based on such analysis. These attempts are related to the increased accuracy and speed and enhanced intelligence of sheet-handling office automation equipment such as printers, facsimile machines, copiers, and automated teller machines. Yoshida et al. conducted a series of studies on the effects of guides forming paper feed paths and of inertia force of paper by approximating sheets with a chain of discrete masses and springs.12-14) This special edition also features a study on sheet sticking and jamming. Okuna et al. handles a system of similar nature, mechanical studying the form of paper guides.15) Introducing mechanisms to control the positioning of sheets is effective in raising sheet transfer accuracy. Feedback control that regulates feed roller skew angle as a manipulated variable is proposed.16) Increased reliability in separating single sheets from stacked effectively reduces the malfunction rate in sheet-handling equipment. Ways of optimizing the form of sheet-separation rollers17) and estimating frictional force between separation gates and sheets 18) are also proposed. This special issue contains a proposal by Nakazawa et al. of a mechanism that uses reactive sheet buckling force, made in connection with development of a newspaper page turner for the disabled as technology for separating single sheets. Dry frictional force is most widely used for transporting sheets, but is not stable and may even act as an obstacle to improving accuracy. Niino et al. propose a sheet transfer mechanism that uses electrostatic force.19) For improving the accuracy of flexible wire transmission, this special issue carries a study on transporting flexible thin wire through tension control at multiple points, from a study by Morimitsu et al. on optical fiber installation. The thickness of wire used in equipment is becoming increasingly slim and flexible, along with the equipment it is used in. Tension control in the production process is an important factor in the manufacture of such thin wire. Production efficiency constantly calls for increased transfer speed. It has thus become important to estimate air resistance and inertia and to measure and control the tension of running wire. Studies20,21) by Batra, Fraser, et al. which deal the motion of string in the spinning process provide good examples for learning analytical techniques for air drag and inertia. In string vibration where inertia dominates, attempts are made to control vibration by boundary shaking22,23) and feed-forward/back control.24) For (d), highly versatile robots for handling cloth are being developed, and the software technology for automatic cloth selection and unfolding by robot hands is a popular topic.25-27) Ono et al. comment on the nature of problems in developing intelligent systems for handling cloth and similar objects whose bending rigidity is low and which readily fold and overlap—a paper that will prove a good reference in basic approaches in this field. Mechanical analyses are indispensable to studies on (a) through (c). In contrast, information technology such as characteristic variable measurement, image processing, and discrimination, rather than mechanical analyses, play an important roles in studies on (d). This special issue features a study by Hamashima, Uraya et al. on cloth unfolding as an example of such studies. Studies up to now largely assumed that properties of grasped objects did not change environmental influences such as temperature and humidity. Such influence is often, however, a major factor in handling fiber thread and cloth. This special issue has a paper contributed by Taylor, who studies handling method to prevent influence by such environmental factors. The objective of this special issue will have been achieved if it aids those studying the handling of flexible objects by providing approaches and methodologies of researchers whose target objects differ and if it aids those planning to take up study in this field by providing a general view of this field. References: 1) Nguyen, W. and Mills, J., ""Multi-Robot Control For Plexible Fixtureless Assembly of Flexible Sheet Metal Auto Body Parts,"" Proceedings of the 1996 IEEE International Conference on Robotics and Automation, 2340-2345, (1996). 2) Sun, D. and Shi, X. and Liu, Y., ""Modeling and Cooperation of Two-Arm Robotic System Manipulating a Deformable Object,"" Proceedings of the 1996 IEEE International Conference on Robotics and Automation, 2346-2351, (1996). 3) Kosuge, K., Sakaki, M., Kanitani, K., Yoshida, H. and Fukuda, T., ""Manipulation of a Flexible Object by Dual Manipulators,"" IEEE International Conference on Robotics and Automation, 318-323, (1995). 4) Nakagaki, H., Kitagaki, K., Ogasawara, T. and Tukune H., ""Handling of a Flexible Wire -Detecting a Deformed Shape of the Wire by Vision and a Force Sensor,"" Annual Conference on Robotics and Mechatronics (ROBOMEC'96), 207-210, (1996). 5) Wakamatsu, H., Hirai, S. and Iwata, K., ""Static Analysis of Deformable Object Grasping Based on Bounded Force Closure,"" Trans. of JSML, 84-618 (C), 508-515, (1998). 6) Katoh, R. and Fujmoto, T., ""Study on Deformation of Elastic Object By Manipulator -Path Planning of End -Effector-,"" J. of the Robotics Society of Japan, 13-1, 157-160, (1995). 7) Yukawa, T., Uohiyama, M. and Inooka, M., ""Stability of Control System in Handling a Flexible Object by Rigid Arm Robots,"" JSME Annual Conference on Robotics and Mechatronics (ROBOMEC'95), 169-172, (1995). 8) Yukawa, T., Uohiyama, M. and Cbinata, G., ""Handling of a Vibrating Flexible Structure by a Robot,"" Trans. JSME, 61-583, 938-943, (1995). 9) Sun, D. and Liu, Y., ""Modeling and Impedance Control of a Two-Manipulator System Handling a Flexible Beam,"" Trans. of the ASME, 119, 736-742, (1997). 10) Nakagaki, H., Kitagaki, K. and Tukune, H., ""Contact Motion in Inserting a Flexible Wire into a Hole,"" Annual Conference on Robotics and Mechatronics (ROBOMEC'95), 175-178, (1995). 11) Shimaji, S., Brata, A. and Hattori, H., ""Robot Skill in Assembling a Cylinder into an Elastic Hose,"" Annual Conference on Robotics and Mechatronics (ROBOMEC'95), 752-755, (1995). 12) Yoshida, K. and Kawauchi, M., ""The Analysis of Deformation and Behavior of Flexible Materials (1st Reprt, Study of Spring-Mass Beam Model of the Sheet,"" Trans. of JSME, 58-552, 1474-1480, (1992). 13) Yoshida, K., ""Analysis of Deformation and Behavior of Flexible Materials (2nd Report, Static Analysis for Deformation of the Sheet in the Space Formed by Guide Plates),"" Trans. JSME, 60-570, 501-507, (1994). 14) Yoshida, K., ""Dynamic Analysis of Sheet Defofmation Using Spring-Mass-Beam Model,"" Trans. JSME, 63-615, 3926-3932 (1997). 15) Okuna, K., Nishigaito, T. and Shina, Y., ""Analysis of Paper Deformation Considering Guide Friction (Improvement of Paper Path for Paper-Feeding Mechanism),"" Trans. JSME, 60-575, 2279-2284, (1994). 16) Fujimura, H. and Ono, K., ""Analysis of Paper Motion Driven by Skew-Roll Paper Feeding System,"" Trans. JSME, 62-596, 1354-1360, (1996). 17) Shima, Y., Hattori, S., Kobayashi, Y. and Ukai, M., ""Optimum of Gate-Roller Shape in Paper Isolating Methods,"" Conference of Information, Intelligence and Precision Equipment (IIP'96), 61-62, (1996). 18) Suzuki, Y, Hattori, S., Shima, Y. and Ukai, M., ""Contact Analysis of Paper in Gate-Roller Handling Method"", Conference on Information, Intelligence and Precision Equipment (IIP'95), 19-20, (1995). 19) Niino, T., Egawa, S. and Higuchi, T., ""An Electrostatic Paper Feeder,"" J. of the Japan Society for Precision Engineering, 60-12,1761-1765, (1994). 20) Batra, S., Ghosh, T. and Zeidman, M., ""An Integrated Approach to Dynamic Analysis of the Ring Spinning Process , PartII: With Air Drag,"" Textile Research Journal, 59, 416-424, (1989). 21) Fraser, W., Ghosh, T. and Batra, S., ""On Unwinding Yarn from a Cylindrical Package,"" Proceedings of Royal Society of London, A, 436, 479-438, (1992). 22) Jacob, S., ""Control of Vibrating String Using Impedance Matching,"" Proceedings of the American Control Conference (San Francisco),468-472, (1993). 23) Lee, S. and Mote, C., ""Vibration Control of an Axially Moving String by Boundary Control,"" Trans. of the ASME, J. of Dynamic Systems, Measurement, and Control, 118, 66-74, (1996). 24) Ying, S. and Tan, C., ""Active Vibration Control of the Axially Moving String Using Space Feedforward and Feedback Controllers,"" Trans. ASME, J. of Vibration and Acoustics, 118, 306-312, (1996). 25) Ono, E., Ichijo, H. and Aisaka, N., ""Flexible Robotic Hand for Handling Fabric Pieces in Garment Manufacture,"" International Journal of Clothing Science and Technology, 4-5,18-23, (1992). 26) Paraschidis, K., Fahantidis, N, Petridis, V., Doulgeri, Z., Petrou, L. and Hasapis, G, ""A Robotic System for Handling Textile and Non Rigid Flat Materials,"" Computers in Industry, 26, 303-313, (1995). 27) Fahantidis, N., Paraschidis, K, Petridis, V., Doulgeri, Z., Petrou, L. and Hasapis, G., ""Robot Handling of Flat Textile Materials,"" IEEE Robotics & Automation Magazine, 4-1, 34-41, (1997).
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Loveikin, V. S., and O. O. Spodoba. "Experimental research of modes of movement of manipulator crane with load at combination of movements." Naukovij žurnal «Tehnìka ta energetika» 11, no. 3 (November 18, 2020): 5–15. http://dx.doi.org/10.31548/machenergy2020.03.005.
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In order to increase the productivity and reliability of a hydraulic-powered loader crane, according to the normative-technical documentation regulating the safe operation of multi-link cranes, it is allowed to combine movements with the simultaneous movement of several links of the boom system. As a result, the paper considers a technique for conducting experimental studies in the plane of changing the boom system of a loader crane with a load. Experimental studies were carried out under the condition of simultaneous angular movement of the jib and a decrease in the linear movement of the telescopic section. To carry out experimental studies, an experimental installation of a hydraulic-driven loader crane was designed and manufactured. Measuring and recording equipment has been selected and adjusted. In the framework of experimental studies of the dynamics of movement of the boom system of a loader crane with a load, a control system for drive mechanisms has been developed, which makes it possible to realize the optimal modes of movement of the links of the boom system. As a result, experimental studies were carried out under the condition of the simultaneous movement of the jib and the telescopic section with a load at the end of the boom system. A package of data on real and optimal modes of movement of the links of the boom system of the loader crane was received. The processed data are presented in graphical form and a comparative analysis with real and optimal modes of movement is carried out. The developed method of experimental research has made it possible to determine the effect of the simultaneous movement of the boom and jib on the oscillations of the load, and the effect of the oscillations of the load on the dynamic loads arising in the boom system and the drive mechanisms of the loader crane.
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Chen, Wen Jia, Yan Zhong He, and Jiang Zhang. "A Four Degrees of Freedom Parallel Manipulator for Machining." Advanced Materials Research 139-141 (October 2010): 2168–71. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.2168.
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In the past decades, a number of parallel manipulators have been extensively studied. However, most efforts are dedicated to six degrees of freedom (DOF) or three-DOF manipulators. There is a need for equipment providing more than three DOF's arranged in parallel and based on simpler arrangements than six-DOF arrangements in application. This paper presents a novel four-DOF parallel platform manipulator with base mounted prismatic actuators. The manipulator is driven by four linear actuators. The movable platform of the manipulator can translate along two directions and rotate around two axes respectively. The kinematics model is formulated, which describes the inverse and forward kinematics transformation. It is very easy to develop a five-axis NC machine-tool which is of large-workspace based on the four-DOF parallel mechanism presented in this paper.
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Платонова, Marina Platonova, Платонов, Aleksey Platonov, Драпалюк, and Mikhail Drapalyuk. "Basic results of research of kinematics and dynamics little links of the mechanism of forest machines." Forestry Engineering Journal 5, no. 4 (December 8, 2015): 208–14. http://dx.doi.org/10.12737/17424.
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Currently, the traffic safety on the railways remains a topical problem of removing unwanted trees and shrubs in the right of way of railways. To improve the efficiency removal of unwanted shoots and branches and stumps, reducing the share of manual labor and facilitation of staff by the authors in 2015 were investigated little links resources saving compact means of mechanization, allowing their use in hard to reach places. These means of mechanization considered in combination with modern the vehicles, which can provide them with the necessary energy, both on the railroad track, and away from it. The design scheme drawn up manipulators for mathematical description of the motion of their units in the plan and profile of the railway, shows a diagram of the dynamic interaction between the rotary operating element with tree and shrub vegetation and stumps, and on the basis of these formulas and reasoned input parameter values it was built a number of plots. The article presents the main findings and recommendations of the study of kinematics and dynamics little links of the mechanism of forest machines. It was concluded that a number of promising kinematic schemes associated with the rotation of the body part telescopic of manipulators machines, substantiated possible working range of the of manipulators according to the scheme of their location on the machine base, a certain range of angles of rotation around the axis of the working equipment of its fastening, the issues of the impact of deviations small diameter unwanted shoots from the vertical cutting force.
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Popikov, P., Irina Chetverikova, and Aleksandr Chernykh. "INCREASING THE TECHNICAL LEVEL OF HYDRAULIC MANIPULATORS OF AUTOCOLLIMATIONAL." Actual directions of scientific researches of the XXI century: theory and practice 8, no. 1 (October 26, 2020): 129–34. http://dx.doi.org/10.34220/2308-8877-2020-8-1-129-134.
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The main requirements for hydraulic equipment of forest transport machines of manipulator type are revealed. It is established that the main drawback of the used hydraulic drives of manipulators is their increased power and high energy consumption. The main ways of increasing the technical level of hydraulic manipulators of forest transport vehicles are considered. The constructive optimization and improvement of the hydraulic drive mechanism for lifting the boom and turning the column of the manipulator is justified. New designs with the use of hydro-mechanical dampers and energy-saving devices are proposed. As energy-saving devices, it is proposed to use a hydraulic accumulator. The main advantages of the design, which are to increase the reliability and expand the technological capabilities of hydraulic manipulators forest transport machines. The principles of influence on the hydraulic system that reduce the pressure in the piston group and reduce energy consumption are substantiated. The proposed energy-saving hydraulic drive reduces the maximum pressure during braking to 3 MPa. The recovery energy when the column is rotated is 25 % of the energy consumed. The diameter of the dampener's lockable cavities should be 48 mm with the internal diameter of the dampener 65 mm. Minimal changes in the design are achieved to increase the technical level of the hydraulic drive of manipulators of forest transport machines and its competitiveness among existing analogues.
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Zhu, Chunxia, Jay Katupitiya, and Jing Wang. "Effect of links deformation on motion precision of parallel manipulator based on flexible dynamics." Industrial Robot: An International Journal 44, no. 6 (October 16, 2017): 776–87. http://dx.doi.org/10.1108/ir-12-2016-0368.
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Purpose Manipulator motion accuracy is a fundamental requirement for precision manufacturing equipment. Light weight manipulators in high speed motions are vulnerable to deformations. The purpose of this work is to analyze the effect of link deformation on the motion precision of parallel manipulators. Design/methodology/approach The flexible dynamics model of the links is first established by applying the Euler–Bernoulli beam theory and the assumed modal method. The rigid-flexible coupling equations of the parallel mechanism are further derived by using the Lagrange multiplier approach. The elastic energy resulting from spiral motion and link deformations are computed and analyzed. Motion errors of the 3-link torque-prismatic-torque parallel manipulator are then evaluated based on its inverse kinematics. The validation experiments are also conducted to verify the numerical results. Findings The lateral deformation and axial deformation are largest at the middle of the driven links. The axial deformation at the middle of the driven link is approximately one-tenth of the transversal deformation. However, the elastic potential energy of the transversal deformation is much smaller than the elastic force generated from axial deformation. Practical implications Knowledge on the relationship between link deformation and motion precision is useful in the design of parallel manipulators for high performing dynamic responses. Originality/value This work establishes the relationship between motion precision and the amount of link deformation in parallel manipulators.
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Yamashina, Hajime, Susumu Okumura, Kazuya Hosoe, and Kenjiro Okamura. "Development of non-contact monitoring equipment for detecting tool failures by optical measurement including auto-focusing mechanism." Journal of the Japan Society for Precision Engineering 55, no. 8 (1989): 1403–8. http://dx.doi.org/10.2493/jjspe.55.1403.
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Посметьев, Viktor Posmetev, Канищев, Denis Kanishchev, Попиков, Petr Popikov, Стороженко, and Stanislav Storozhenko. "Modeling workflows of energy-saving hydraulic drive of technological equipment of timber-hauling machine." Forestry Engineering Journal 5, no. 1 (May 1, 2015): 223–34. http://dx.doi.org/10.12737/11280.
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Workflow mechanisms of forestry cranes tower rotation are accompanied by large dynamic loads that cause sudden changes in fluid pressure in balancing and braking modes. When the rotary column stops at different positions damping of pressure of the working fluid vibration occurs due to its overflow from one chamber to another through an orifice, wherein the hydraulic energy is transformed into heat one, resulting in overheating and energy loss of fluid. Efficient are energy-saving hydropneumatic drives of column of the manipulator which are able to recover energy during transient conditions and to return some of the energy back into the system. For hydraulic manipulators with four paired hydraulic cylinders of rotation mechanism of the column one pair of cylinders is proposed to be replaced by pneumatic cylinders connected to a rotary column through the gear and toothed rack that allows you to transfer it into recovery mode of energy. A mathematical model of the boom rotation of the manipulator is developed; equations for a hydro pneumatic system recovery are made. In the model three mechanical processes are considered: the rotational movement of the column about the vertical axis of the manipulator, the forward movement of the plunger along the axis of the damper, and sway of the load relative to the attachment point on the manipulator arm. To solve the system of differential equations, computer program for the simulation of hydraulic manipulator equipped with a hydraulic damper is composed. The dependence of the restoring force of the displacement of the toothed rack is get. In the vicinity of the equilibrium position, this dependence is nearly linear over a wide range of rack movement: from about 50 to 180 mm. With significant turns of the column volume of one of the chambers of the air cylinder approaches zero value, whereby the restoring force of the module increases significantly, which helps braking of the column in the final step of rotation and influences the process of energy accumulation.
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Ivanova, Natalia. "Biomimetic optics: liquid-based optical elements imitating the eye functionality." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2167 (February 3, 2020): 20190442. http://dx.doi.org/10.1098/rsta.2019.0442.
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The optical systems mimicking the eye functions are of great importance in various applications including consumer electronics, medical equipment, machine vision systems and robotics. This optics offers advantages over traditional optical technologies such as the superior adaptation to changing conditions and the comprehensive range of functional characteristics at miniature sizes. This paper presents a review on the recent progress in the development of human eye-inspired optical systems. Liquid-based and elastomer-based tunable optical elements are discussed with the focus on the actuation mechanism, optical performance and the possibility of integration into artificial eye systems. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 3)’.
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Kozhevnikov, D. A., R. V. Fiodоrtsev, and A. R. Silie. "Synthetic Aperture Orbital Telescope for Earth Remote Sensing Equipment." Devices and Methods of Measurements 9, no. 4 (December 17, 2018): 280–87. http://dx.doi.org/10.21122/2220-9506-2018-9-4-280-287.
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The object of the research is the development of the method of aperture synthesis of a mirror system designed for remote sensing of the Earth.The analysis of existing methods for the formation of the synthesized aperture was carried out, their accuracy, cost, and mass-dimensional characteristics were evaluated. A new version of the optical system of the synthetic aperture mirror lens is presented and its optimization is performed in the Zemax software package. An estimate of the accuracy of the designed system has been made; a design variant has been developed that includes a transformation mechanism when the telescope is put into near-earth orbit.As a result of the study, the design parameters of the base lens were determined: a focal length of 13 m, a main mirror diameter of 800 mm, a field angle of 0.25° for modifying a telescope for a low orbit; and the entire telescope as a whole: the lag from the main axis of the telescope is 1.2 m, the angle of rotation of the flat mirror for combining images (45 + 1,5)°, the signal-to-noise ratio (189 in a low orbit with an angle of the Sun 0°, 15 in the geostationary orbit with a sun angle of 60°).It has been established that the use of aperture synthesis technology allows the development of highresolution optical-electronic systems with lower production and operation costs compared with classical methods for forming the surface of the main mirror. In the course of the simulation, the instability of the values of the frequency-contrast characteristic with increasing angle of view was determined, which is important for a low near-earth orbit, and the requirement for positioning elements of the optical system was established.
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Chen, Qing Hua, Yan Mei Li, Ying Jun Chen, and Wen Gang Wu. "Development of MEMS VOA with only One Shutter for Dual Signals Simultaneous Operation." Advanced Materials Research 709 (June 2013): 481–84. http://dx.doi.org/10.4028/www.scientific.net/amr.709.481.
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A MEMS variable optical attenuator (VOA) with only one shutter for dual signals simultaneous operation is designed for advanced tuning functions. Theoretical electro-mechanism model has also been developed to provide optimization for the VOA design. In experiment, the fabricated VOA device has demonstrated a over 40-dB attenuation range with respect to the driving voltage of one shutter, and it has also realized low polarization-dependent performance. The superior specifications make this device very promising for optical network systems and laboratory equipment.
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Hsieh, Ming-Chu, and Zhen-Hong Khong. "Design and analysis for manipulator fixture applications." MATEC Web of Conferences 185 (2018): 00031. http://dx.doi.org/10.1051/matecconf/201818500031.
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The manipulators arms are the most important components in automatic machinery and equipment. These arms must conform to product requirements and match important accessory devices such as clamping jaw so that the entire process operates properly. Therefore the most important issue is that the manipulator arm has only one clamping jaw, followed by other issues such as welding and related features. In this research the manipulator arm of automated machinery with attached equipment was optimized, and the design serves as an object of study for multifunctional applications. This research emphasizes on customized manipulator design to create products with distinguished styles and characteristics, and serve as a basis for an improvement on innovative design. Manipulator arms from different manufacturers with various head-disc size and screw-hole locations were investigated, and concept of human palm was incorporated in the design to create a mechanical fixture that can be fitted into the arm. Overall design including main body of the manipulator, pneumatic cylinder set, gear and connecting rod combination, planet gear set, and linkage rods and fixture. These components were combined to offer the functions of the manipulator. Commercial software package, SolidWorks, was used to construct the model for the manipulator arm, and CAE analysis was implemented to identify the stress on the structure and possible interferences of the mobile components. Stress analysis was also performed on the gear set under pneumatic loading to ensure that the gear mechanism has a sufficient strength. The results of this study showed that an arc shaped manipulator body is the most easily handled during installation and most effectively controlled during operation. The simple profiles of the manipulator also lower the space required for storage. The design of the gear set and integrated application of the shaft helps prevent loosening of gear and shaft during operation. In this study, a manipulator was designed with three different functions, each fixture is powered by an isolated pneumatic cylinder, and this mechanism can be manipulated to form o0to o180clamping action in accordance with requirements of the task. The methods and results of this study serve as a reference for machinery industry to achieve high quality product, and also as a basis for innovative design.
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Piao, Chunde, Jun Yuan, Dangliang Wang, and Pengtao Li. "A Study on Distribution Measurement and Mechanism of Deformation due to Water Loss of Overburden Layer in Vertical Shaft." Journal of Sensors 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/531428.
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Based on FBG fiber Bragg grating technology and BOTDA distributed optical fiber sensing technology, this study uses fine sand to simulate overburden layer in vertical shaft model equipment. It studies the placing technique and test method for optical fiber sensors in the overburden layer, combined with MODFLOW software to simulate the change of the water head value when the overburden layer is losing water, and obtains the deformation features of overburden layer. The results show, at the beginning of water loss, the vertical deformation increases due to larger hydraulic pressure drop, while the deformation decreases gradually and tends to be stable with the hydraulic pressure drop reducing. The circumferential deformation is closely related to such factors as the distance between each drainage outlet, the variations of water head value, and the method of drainage. The monitoring result based on optical fiber sensing technology is consistent with the characteristics of water loss in overburden layer simulated by MODFLOW software, which shows that the optical fiber sensing technology applied to monitor shaft overburden layer is feasible.
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Zhou, Yu Tong, Jiong Geng Wang, Hong Ye Zheng, Jie Zi Hu, Jie Zhang, and Jia Yuan Hu. "Corrosion Mechanism Analysis of a 20# Carbon Steel Lightning Rod on a Substation." Key Engineering Materials 730 (February 2017): 81–86. http://dx.doi.org/10.4028/www.scientific.net/kem.730.81.
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A lightning rod on a coastal substation cracked, so the related equipment is forced to be shut down. Optical microscope, spectrometer, SEM, EDS and ion chromatograph were adopted to analyze the corrosion mechanism. Results show that the lightning rod is corroded severely. The material of this lightning rod is 20# carbon steel. The corroded part and the uncorroded part are divided into two layers. Nodulizing of pearlites is evident in the microstructure of corroded area. Both of EDS and ion chromatograph detect high concentration of chloride ion and sulfate ion from the corrosion products. In this sense, corrosion is probably induced by coastal-industrial atmosphere and rainwater pollution. Besides, improper structure of the lightning rod is also a factor to cause the corrosion.
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Maruyama, Takahiro. "Elucidation of carbon nanotube formation mechanism by operand EXAFS measurement." Impact 2020, no. 1 (February 27, 2020): 68–70. http://dx.doi.org/10.21820/23987073.2020.1.68.
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Nanomaterials are the up-and-coming players in materials science and increasingly found in everyday products such as energy devices, photocatalyst and sporting equipment. They are also predicted to play a major future role in electronics and microfabrication fields. The term nanomaterials usually describe materials of which a single unit ranges in size from 1 to 100 nanometres (nm). A specific nanomaterial called a carbon nanotube is exactly this, a tube made of carbon with a diameter measurable in nanometres. While carbon nanotubes can be further segregated into further subtypes with varying properties, generally speaking they are among the strongest and stiffest materials known in terms of tensile strength and elasticity. These miniature tubes also have promising electrical and optical properties in that they can operate as semiconductors, thermal conductors or even be employed for absorption and fluorescence applications. Because of this broad range of useful properties, the design and use of carbon nanotubes for a variety of applications and industries is receiving lots of attention. Professor Takahiro Maruyama, who is based at both the Nanomaterial Research Centre and the Department of Applied Chemistry, Meijo University in Japan, is leading a team conducting research in this field.
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Selin, V. A., A. A. Emelyanov, O. S. Sizov, K. S. Emelyanov, and A. V. Borisov. "Evaluation of functional expectations of thematic consumers from optical space remote sensing systems of medium resolution." Исследования Земли из Космоса, no. 5 (November 5, 2019): 89–98. http://dx.doi.org/10.31857/s0205-96142019589-98.
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According to the results of direct interaction with various groups of consumers, it was established that the structure of requirements in all thematic areas at the present time comes to the fore geographic coverage, regularity and frequency of shooting. The second priority is to ensure the quality of the spectroradiometric characteristics in the context of their absolute performance and stability in the time series of the entire archive of the survey with the ability to provide data in physical quantities of reflectivity, or spectral brightness of the reflected radiation / brightness temperature. The requirements for spatial resolution within a separately allocated class of data, as well as the presence of a panchromatic channel are not significant for the majority of respondents. In the understanding of thematic users, the mediated requirements for the characteristics of the target remote sensing equipment are formed through direct requirements for the initial remote sensing data. When creating a promising ERS satellite on the part of the state customer, it is advisable to conduct regular advanced studies of user expectations and preferences in order to fully coordinate and integrate them into technical specifications for various products of the space system. In general, for effective generalization of various, often opposite, functional expectations, it is advisable to conduct a comprehensive discussion that provides a feedback mechanism from both authorized representatives of main consumers and developers of target equipment and space remote sensing systems.
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Yao, Jun Ping, and Sun Zhong. "Research on the Alkali Corrosion Resistance Mechanism of Ni-Cr-Cu Alloy Cast Iron." Advanced Materials Research 230-232 (May 2011): 1298–302. http://dx.doi.org/10.4028/www.scientific.net/amr.230-232.1298.
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In allusion to facility corrosion problem in caustic soda industry five types of ni-Cr-cu alloy cast irons were developed. The corrosion rates of ni-Cr-cu alloy cast irons in hot concentrated alkali solution were measured by using self-made dynamic corrosion experiment equipment; the microstructures and surface corrosion morphology of alloy cast irons were observed by means of the optical microscope and SEM; the composition was analyzed using XES. Corrosion resistance mechanism were discussed detailedly. the experimental results showed that ni-Cr-cu cast iron was uniform corrosion macroscopically in the dense caustic soda at high temperature and there was ni, cu enrichment microcosmically. The Ni and Cu enriched in the matrix , which increase in local electrode voltage of the matrix,are advantageous to the improvement of caustic corrosion resistances of that zone. The higher Ni content,the better alkali corrosion resistance performance with high temperature.
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Kartashov, S. G., and E. M. Klychev. "Method for preparation of feed drug mixtures with anthelmintics." Russian Journal of Parasitology 12, no. 1 (February 27, 2018): 70–75. http://dx.doi.org/10.31016/1998-8435-2018-12-1-70-75.
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The purpose of the research: to develop an innovative method for simultaneous single-stage preparation of feed drug mixtures and a technological scheme for implementation of this method. Materials and methods. The innovative method of simultaneous single-stage preparation of feed drug mixtures from filling compound (grinded grain forage) containing anthelmintics is developed. Technical means used for implementation of this method include a loading track, robotic discharger, mobile dosage device, robotic depanner, blender and a mixer. The work cycle begins when the robotic depanner is switched on while its horizontal upper telescopic boom with a small gripper moves out and selects by barcode the necessary container with the anthelmintic specified in the animal therapy program; then this container is moved from the upper boom to the location of lower boom with the chopper housing. The small gripper ensures the pouring of therapeutic drug from the open top container to the chopper; then returns then container to this original position. Herein, according to the program set by the microprocessor the screw discharger pours the necessary dose of filler (30%) from the supply bunker to the shredder where co-milling occurs; therapeutic drug and filler are mixed within 3 min. what provides the receiving of working premix. Lower boom (with a large gripper) brings the shredder to the neck of the main mixer; the adjustable mechanism of the shredder opens the lid of its housing; the large gripper turns it and the working premix is poured into the main mixer with the adjustable electric wire. The final dose of filler (70%) is dosed with the use of the screw feeder to the main mixer where is mixed within 4 minutes with the working premix; that provides the receiving of feed drug mixture. From the main mixer mixture is poured with the inclined conveyor into the feeder, which distributes feed drug mixture to free feeding sick animals. Operation of the entire equipment is carried out by a microprocessor. Results and discussion. According to research results, the innovative method for simultaneous single-stage preparation of feed drug mixtures and a technological scheme for implementation are proposed. To implement this method we have used equipment made in block-and-module performance with the use of robots and manipulators. An effective method of impulse introduction of liquid therapeutic drugs is also used in mixer design. A technological scheme of the single-stage preparation of feed drug mixtures is presented. The equipment of this line can be installed both stationary indoor and in a trailer or a van.
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Maneski, Taško, and Biserka Nestorović. "Validation numerical modeling with 3D optical measurement of deformations of foldable plastic packaging buckling failure." SAJ - Serbian Architectural Journal 3, no. 3 (2011): 152–63. http://dx.doi.org/10.5937/saj1102152m.
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This paper describes the numerical and experimental methodology for analysis of plastic packaging buckling characteristics that are representative of its strength in the real life. The experiments were executed with 'GOM' equipment and 'ARAMIS' software application for modern optical 3D measurement of deformations. Numerical analysis was conducted by the application of finite elements using 'KOMIPS' software. The fundamental question to be answered is related to the mechanism of failure of foldable packaging - does the buckling precede plasticity or vice versa? This article will show how experimental results can be predicted by means of finite element analysis; this is found a very strong learning tool that would enable designers to improve the structural strength of the new products in future. Experimental and numerical analysis results to date have shown high degree of correlation. This paper describes the access that allows real structure behavior diagnostic, reliable prospect for structure in exploitation reacting, elements receiving for different decision making (operating regime, rehabilitation, reconstructions, revitalizations, optimization, confirmation to variable solution selection and so on), poor performance sample defining or structure loosening, structure life time estimation and similar. The described developed diagnosis access is shown in solved examples.
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Berkelman, P., P. Cinquin, E. Boidard, J. Troccaz, C. Létoublon, and J.-M. Ayoubi. "Design, control and testing of a novel compact laparoscopic endoscope manipulator." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 217, no. 4 (June 1, 2003): 329–41. http://dx.doi.org/10.1177/095965180321700409.
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This paper describes the development of a compact laparoscopic endoscope manipulator and its command interface for use as a surgical assistant during minimally invasive surgery. The defining feature of the endoscope manipulator is that it is sufficiently small and lightweight to be fixed directly on the abdomen of the patient. The mechanism of the manipulator controls the orientation of the endoscope and its insertion depth. It is actuated by cables inside flexible sleeves connected to a separate enclosure containing analogue controllers, servomotors and rack-and-pinion drives. Compared with floor-standing endoscope manipulators, the described device is easier to set up, cheaper, simpler and allows unrestricted access to the abdomen from all sides of the patient. The pointing accuracy of the device is reduced by the absence of a rigid base, but the resulting compliance to patient motion is an added benefit. The current prototype has been tested on a cadaver. The design and control of the endoscope manipulator continues to evolve in response to testing results and consultation with surgeons, with light weight, small size, simplicity and ease of use as primary considerations. A novel hands-free user control interface for orientation of the endoscope manipulator using an external optical localizer to track surgical instruments is also presented.
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Rząsa, Mariusz R. "Comparison of selected theoretical models of bubble formation and experimental results." Archives of Thermodynamics 35, no. 2 (June 1, 2014): 21–36. http://dx.doi.org/10.2478/aoter-2014-0011.
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Abstract Designers of all types of equipment applied in oxygenation and aeration need to get to know the mechanism behind the gas bubble formation. This paper presents a measurement method used for determination of parameters of bubbles forming at jet attachment from which the bubles are displaced upward. The measuring system is based on an optical tomograph containing five projections. An image from the tomograph contains shapes of the forming bubbles and determine their volumes and formation rate. Additionally, this paper presents selected theoretical models known from literature. The measurement results have been compared with simple theoretical models predictions. The paper also contains a study of the potential to apply the presented method for determination of bubble structures and observation of intermediate states.
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Nazari, Marziyeh, Abbas Amini, Nathan T. Eden, Mikel C. Duke, Chun Cheng, and Matthew R. Hill. "Highly-Efficient Sulfonated UiO-66(Zr) Optical Fiber for Rapid Detection of Trace Levels of Pb2+." International Journal of Molecular Sciences 22, no. 11 (June 3, 2021): 6053. http://dx.doi.org/10.3390/ijms22116053.
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Lead detection for biological environments, aqueous resources, and medicinal compounds, rely mainly on either utilizing bulky lab equipment such as ICP-OES or ready-made sensors, which are based on colorimetry with some limitations including selectivity and low interference. Remote, rapid and efficient detection of heavy metals in aqueous solutions at ppm and sub-ppm levels have faced significant challenges that requires novel compounds with such ability. Here, a UiO-66(Zr) metal-organic framework (MOF) functionalized with SO3H group (SO3H-UiO-66(Zr)) is deposited on the end-face of an optical fiber to detect lead cations (Pb2+) in water at 25.2, 43.5 and 64.0 ppm levels. The SO3H-UiO-66(Zr) system provides a Fabry–Perot sensor by which the lead ions are detected rapidly (milliseconds) at 25.2 ppm aqueous solution reflecting in the wavelength shifts in interference spectrum. The proposed removal mechanism is based on the adsorption of [Pb(OH2)6]2+ in water on SO3H-UiO-66(Zr) due to a strong affinity between functionalized MOF and lead. This is the first work that advances a multi-purpose optical fiber-coated functional MOF as an on-site remote chemical sensor for rapid detection of lead cations at extremely low concentrations in an aqueous system.
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Abdelrhman, Yasser, Ahmed Abouel-Kasem, Karam Emara, and Shemy Ahmed. "The effect of boronizing heat treatment on the slurry erosion of AISI 5117." Industrial Lubrication and Tribology 70, no. 7 (September 10, 2018): 1176–86. http://dx.doi.org/10.1108/ilt-01-2017-0009.
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PurposeThis paper aims to clarify the relationship between the slurry erosion and one of the case hardening treatments, i.e. boronizing in this study, for AISI-5117 steel alloy. AISI-5117 steel alloy was used because of its variety applications in the field of submarine equipment. Most of the slurry erosion factors such as velocity, impact angle and mechanism of erosion were studied at different impact angles.Design/methodology/approachAt first, the samples were prepared and subjected to the boronizing treatment in controlled atmosphere. By using a slurry erosion test-rig, all experiments for studying the slurry erosion factors were carried out. Moreover, the studied specimens were investigated via scanning electron microscope, optical microscope and X-ray diffraction to study the erosion mechanism in the different conditions.FindingsIt was expected that the boronization of the AISI-5117 steel would increase its slurry erosion resistance due to its positive impact on the surface hardness. However, the results observed show the opposite, where the boronization of AISI-5117 steel decreased its slurry erosion resistance as implied by the increase of the mass loss percentage at all impact angles.Originality/valueThis research, for the first time, exhibits the effect of boronizing treatment on the slurry erosion in different impact factors accompanied by the erosion mechanism at each impact angle.
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Yang, Huiping, Dingbo Chen, Yuliang Mao, and Junbo Yang. "Tunable Broadband THz Waveband Absorbers Based On Graphene for Digital Coding." Nanomaterials 10, no. 9 (September 15, 2020): 1844. http://dx.doi.org/10.3390/nano10091844.
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A method of coding patterns is proposed to achieve flexible control of absorption response at terahertz frequencies. The designed absorber consists of an Au-graphene pattern layer, a SiO2 layer and a metal reflective layer. Among them, we use concentrical circle structure to achieve broadband absorption, and adjust graphene’s Fermi level to achieve tunable absorption. In addition, we propose an encoding method that can achieve flexible control of the absorption response at the terahertz frequency based on the external voltage applied on the graphene membrane, thereby having a programmable function. We also use COMSOL to simulate the electric field distribution diagram to explain the underlying physical mechanism. The programmable broadband adjustable absorber proposed in this paper has potential application prospects in the fields of optical equipment, information transmission, digital coding and artificial intelligence (AI).
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Gao, Bo, and Minglong Xu. "Measurement of frequency characteristics of disturbance torque in the process of satellite antenna rotation." International Journal of Applied Electromagnetics and Mechanics 64, no. 1-4 (December 10, 2020): 1563–69. http://dx.doi.org/10.3233/jae-209478.
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As an important equipment for satellite signal reception and transmission, the satellite antenna needs to be rotated in real time to achieve real-time tracking of the target and complete signal transmission during applications. Antenna driving mechanism is generally composed of motor and other components, which will cause some structural vibration during rotation. For high-stability satellite applications, the vibration disturbance torque is a major factor affecting the satellite stability. In order to study characteristics of the disturbance torque, the disturbance data from the antenna under different rotation conditions should be measured. In this paper, the frequency characteristics of disturbance torque of a rotating satellite antenna using stepper motor as driving motor is tested and discussed.
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Muralikrishna, Kondaveeti, ShafiShahsavar Mirza, and Satbir Singh Dhula. "A New MIM Directional Coupler With Twin Bands for Photonic ICs." International Journal of Electronics, Communications, and Measurement Engineering 9, no. 2 (July 2020): 30–40. http://dx.doi.org/10.4018/ijecme.2020070103.
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For processing of desired information, the present-day electronic equipment is rapidly approaching their ultimate speed and bandwidth constraints, which is an ever more serious problem that prevents their persistent use in applications. It is believed that a promising solution is to fabricate electronic and photonic elements on a single chip. This mechanism provides a larger bandwidth that is used to construct new hybrid electronic photonic devices. In this paper the numerical analysis and design of metal-insulator-metal plasmonic directional coupler are presented. In dual optical bands, this directional coupler design needed the concept of the step impedance resonators (SIRs). Without reducing the subsystems, the enhanced architectures that pertain to filtering as well as multiplexing devices are necessary for conclusion of these kinds of specifications. Photonic-integrated circuits (PICs) have effectively improved their work by present design directional coupler, and it can be mixed with the conventional silicon PICs.
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Du, Zhang, and Zhang. "Effect of Heat Treatment on the Cavitation Erosion Performance of WC–12Co Coatings." Coatings 9, no. 10 (October 22, 2019): 690. http://dx.doi.org/10.3390/coatings9100690.
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WC–12Co coatings were deposited on 16Cr5Ni stainless steel substrate by high-velocity oxygen fuel (HVOF) process, followed by a one-hour heat-treatment in a tube furnace with a nitrogen atmosphere at 650, 800, 950, and 1100 °C, respectively. The influence of heat-treatment temperature on properties and cavitation erosion resistance of as-sprayed and heat-treated WC–12Co coatings was studied. The cavitation erosion test was carried out with ultrasonic cavitation erosion equipment. The porosity, microhardness, phase composition, as well as surface and cross-section morphology of the coatings were characterized. The coating heat-treated at 800 °C showed three typical cavitation erosion stages and exhibited the best cavitation erosion resistance. The cavitation erosion resistance was closely related to the coating microstructure and heat-treatment process. 3D optical microscopy was used to analyze the eroded surface of the coatings. The cavitation erosion mechanism of the coatings was discussed.
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Ding, Wen-Hua, Xiao-Peng Xie, PAN-Feng Zhang, and Lei Han. "A Novel Tension Control System of Square Lithium Battery Laminated Machine." Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) 13, no. 1 (February 20, 2020): 69–79. http://dx.doi.org/10.2174/2352096512666190411112015.
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Background: To the problem that the traditional square laminated machine with passive unwinding control strategy makes the tape speed periodical changing in reciprocating motion and not achieve a good tension control, a novel unwinding system and control algorithm are presented to improve the efficiency and quality of such equipment. Methods: Compared with the traditional passive unwinding control system, the novel tension control system adds an active compliance mechanism. After obtaining the motion relationship between the compliance device and the laminated motion platform through building the complex system mathematical model, the laminated machine tension control is equivalent to a spatial trajectory tracking control, and multi-axis synchronous coordinated control algorithm is used to control their relative motions, and a cross-coupling control in multi-axis coordinated motion is presented to decrease the synchronous error of the two linear servo motors, which are the compliance device driving motor and the laminated motion platform driving one. Without tension sensor, however, good tension control is obtained only by position tracking control. Results: Based on the proposed approaches and novel unwinding mechanism, the tension control was examined on an experimental square lithium battery laminated machine and results of the experiments performed with the experimental setup demonstrated the effectiveness of the proposed approach. Conclusion: Without a tension sensor, good tension control is obtained only by position tracking control in the novel unwinding system, and the production quality and efficiency of the lithium battery laminated machine are improved.
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Mocák, Ján, Michal Németh, Mieczyslaw Lapkowski, and Jerzy W. Strojek. "Spectrocoulometry – a new spectro-electrochemical technique." Collection of Czechoslovak Chemical Communications 52, no. 6 (1987): 1386–96. http://dx.doi.org/10.1135/cccc19871386.
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A spectrocoulometric macrocell with a direct-view optical probe was designed and constructed, where the optical signal is transferred by light-conducting glass or quartz fibres permitting to work at wavelengths above 410 or 300 nm. The method of measurement on the proposed equipment is described; it was tested in the study of the mechanism and kinetics of oxidation of Fe(bipy)32+ ions (bipy = 2,2'-bipyridyl) with the use of potentiostatic coulometric electrolysis with open-circuit relaxation at a suitable time. The primary product of electrolysis, Fe(bipy)33+, undergoes a follow-up hydrolytic reaction with the formation of a binuclear complex. The rate constant of the reaction of the first order involves the contributions, kBi, from all bases present in solution; the corresponding values for H2O, OH-, bipy, and CH3COO- ions at a ionic strength 0·5 mol dm-3 and 25 °C were determined as kOH = (5·0 ± 0·6) . 105 mol-1 dm3 s-1, kbipy = (1·3 ± 0·2) . 10-1 mol-1 dm3 s-1, kAc = (5·8 ± 1·0) . 10-2 mol-1 dm3 s-1, and kH2O is not significant with respect to experimental errors.
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Zhang, Rui Bin, Yi Ping Huang, Hai Lang Liu, and Zhi Guo Peng. "Irradiation Damage of Electron-Beam on High-Power AlInGaP Red LED." Advanced Materials Research 415-417 (December 2011): 1297–301. http://dx.doi.org/10.4028/www.scientific.net/amr.415-417.1297.
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In this paper, experimental results and Monte Carlo simulation methods used to study irradiation damage of Electron-beam on high-power AlInGaP red LED. The electron beam range and distribution of energy loss in the LED chip are analyzed by CASINO program in detail, the high-power AlInGaP red LED is irradiated by different energy and dose of electron beam irradiation produced by the low energy electron beam irradiation equipment. We contrast the optical parameter of the irradiated LED with the unirradiated LED. The experimental result is analyzed and discussed by the mechanism of electron beam irradiation. The results show that: the luminous flux and power change of the irradiated and unirradiated LED are showed by dose-response. In process of irradiation, the elastic collision and ionization are occurred between the incident particles and atoms within the material, which cause defect in the internal structure of the AlInGaP material and form the color centers.
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Wang, Yanxia, and Xingcang Zhai. "Comparison and Analysis of Electronic Voltage Transformer Based on Voltage Detection." Electronics Science Technology and Application 2 (December 4, 2015): 48. http://dx.doi.org/10.18686/esta.v2i1.10.
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The electronic voltage Transformer (EVT) constitutes key equipment in the intelligent substation; during the half-a-century development, numerous categories have emerged. By analysis and comparison of the working mechanisms and features of various electronic voltage transformers, we have concluded the strengths and defects in various mechanisms and impact factors on the features of voltage transformer and raised specific measures to reduce the impact and problems found in the design. The findings have revealed that ECVT is the mainstream product in the electronic voltage transformer market but interim measuring accuracy requires for improvement; ERVT is limited by the resistance power and insulating property, and not applicable to the higher voltage level; OVT assures excellent measuring quality in the sensing mechanism. However, the application progress will be slowed down due to several factors: the complex production process, measuring precision easily affected by light power fluctuation and temperature change and transmission by optical fibers with a little effect in simplifying insulation and trimming cost.
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Raven, Sara, Emel Cevik, and Michael Model. "Assessing the Effectiveness of a Novel Microscopy Technique in Middle & High School Science Classrooms." American Biology Teacher 82, no. 7 (September 1, 2020): 463–69. http://dx.doi.org/10.1525/abt.2020.82.7.463.
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Although research and new technologies have introduced different ways of observing microorganisms, including scanning and electron microscopy, these methods are expensive and require equipment that is typically not found in a middle school classroom. The transmission-through-dye technique (TTD; Gregg et al., 2010), a new optical microscopy method that can be used with current basic light microscopes, relies on the fairly simple mechanism of filtered light passing through a dyed medium to produce an image that reflects cell thickness. With this technique, living microorganisms look bright red against a dark background, and movement can be seen easily among dead microorganisms and debris that show up black. Since the technique is low-cost and easy to implement, it addresses the needs of practitioners and is appropriate for a wide array of school contexts. We describe a three-week, hands-on, inquiry-based unit on TTD microscopy for middle and high school students.
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Huang, Po-Wei, Hsin-Shu Peng, and Wei-Huang Choong. "Mold-Face Heating Mechanism, Overflow-Well Design, and Their Effect on Surface Weldline and Tensile Strength of Long-Glass-Fiber-Reinforced Polypropylene Injection Molding." Polymers 12, no. 11 (October 25, 2020): 2474. http://dx.doi.org/10.3390/polym12112474.
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Long-fiber polymers offer the advantage of a lower production cost because specific tool designs are required for conventional injection molding equipment to produce long-fiber polymer parts. The use of long fibers allows relatively high fiber aspect ratios to be obtained, thereby enhancing composite stiffness, strength, creep endurance, and fatigue endurance. However, the multigate design of the injection-molded part can result in weldline formation during the molding process, which reduces the structural strength of the molded part. Therefore, in this study, the surface quality, fiber compatibility, and structural strength of long-glass-fiber-reinforced polypropylene (PP/LGF) injection-molded samples were compared in the use versus nonuse of a mold-cavity overflow-well area and the mold-face infrared heating method. The experimental results indicate that the mold-cavity overflow-well area more greatly improved the surface roughness of the PP/LGF molded samples. Moreover, the infrared heating of the mold-face decreased the weldline depth of the samples. Optical-microscopy images and mold-cavity pressure distributions indicated that the weldline tensile strength and the interface compatibility between fibers and melts at the weldline region during the molding stage were higher in the use than in the nonuse of the mold-cavity overflow-well and mold-face infrared heating method.
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Kozeruk, A. S., Y. L. Malpica, M. I. Filonova, V. I. Shamkalovich, and R. O. Dias Gonzalez. "MATHEMATICAL MODELING OF OPERATIONAL ZONE FOR TECHNOLOGICAL EQUIPMENT USED FOR DOUBLE-SIDED PROCESSING OF LENSES." Science & Technique 17, no. 3 (May 31, 2018): 204–10. http://dx.doi.org/10.21122/2227-1031-2018-17-3-204-210.
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A mathematical modeling of geometric and kinematic relations has been made in respect of an operational zone for one of the standard machine tool sections which is used for simultaneous double-sided abrasive processing of highly-accurate lenses with a small rigidity (with a thin centre) under free lapping conditions. An analytical expression has been obtained for calculation of a sliding velocity in an arbitrarily selected point either on a surface to be processed or on a processing surface. As the proposed technology for simultaneous double-sided processing presupposes oscillatory motion of only processing tools then in order to eliminate a joint opening (a local contact fault between lapping surfaces of a tool and a work-piece) length of a drive piece must be not less than a specified value. In this case a convex tool is rigidly connected with a drive piece and it makes a reversing rotary motion (an oscillatory motion) around a centre of the processed spherical surface and a hinged joint of the centre with an output element of the technological equipment actuation mechanism is realized by transition of the drive piece ball end with a spherical seat in the output unit. In order to reveal analytical dependence of tool drive piece length on radius value of the processed spherical lens surface and friction coefficient in the contact zone of the tool and a work-piece the paper has considered a flow pattern of force while processing concave surfaces of lenses having small radius of curvature in case when the tool is positioned at the top. The friction coefficient included in the obtained expression has been determined for grinding while using suspensions of М40, М28, М10 micro-powders in a cast-iron grinding instrument and polishing while using polyrhythm suspension in a pitch and urethane-foam polisher. A method of the inclined plane has been used in this case and following the method a work-piece of optical glass has been initially lapped to the tool with the help of the appropriate abrasive suspension and the required angle has been determined at the moment when the work-piece started its sliding movement along the tool surface.
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Ren, Bin, Xurong Luo, and Jiayu Chen. "Single Leg Gait Tracking of Lower Limb Exoskeleton Based on Adaptive Iterative Learning Control." Applied Sciences 9, no. 11 (May 31, 2019): 2251. http://dx.doi.org/10.3390/app9112251.
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The lower limb exoskeleton is a wearable human–robot interactive equipment, which is tied to human legs and moves synchronously with the human gait. Gait tracking accuracy greatly affects the performance and safety of the lower limb exoskeletons. As the human–robot coupling systems are usually nonlinear and generate unpredictive errors, a conventional iterative controller is regarded as not suitable for safe implementation. Therefore, this study proposed an adaptive control mechanism based on the iterative learning model to track the single leg gait for lower limb exoskeleton control. To assess the performance of the proposed method, this study implemented the real lower limb gait trajectory that was acquired with an optical motion capturing system as the control inputs and assessment benchmark. Then the impact of the human–robot interaction torque on the tracking error was investigated. The results show that the interaction torque has an inevitable impact on the tracking error and the proposed adaptive iterative learning control (AILC) method can effectively reduce such error without sacrificing the iteration efficiency.
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Ma, Chao-Tsung, Cheng-Ling Lee, and Yan-Wun You. "Design and Implementation of a Novel Measuring Scheme for Fiber Interferometer Based Sensors." Sensors 19, no. 19 (September 21, 2019): 4080. http://dx.doi.org/10.3390/s19194080.
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This paper presents a novel measuring scheme for fiber interferometer (FI) based sensors. With the advantages of being small sizes, having high sensitivity, a simple structure, good durability, being easy to integrate fiber optic communication and having immunity to electromagnetic interference (EMI), FI based sensing devices are suitable for monitoring remote system states or variations in physical parameters. However, the sensing mechanism for the interference spectrum shift of FI based sensors requires expensive equipment, such as a broadband light source (BLS) and an optical spectrum analyzer (OSA). This has strongly handicapped their wide application in practice. To solve this problem, we have, for the first time, proposed a smart measuring scheme, in which a commercial laser diode (LD) and a photodetector (PD) are used to detect the equivalent changes of optical power corresponding to the variation in measuring parameters, and a signal processing system is used to analyze the optical power changes and to determine the spectrum shifts. To demonstrate the proposed scheme, a sensing device on polymer microcavity fiber Fizeau interferometer (PMCFFI) is taken as an example for constructing a measuring system capable of long-distance monitoring of the temperature and relative humidity. In this paper, theoretical analysis and fundamental tests have been carried out. Typical results are presented to verify the feasibility and effectiveness of the proposed measuring scheme, smartly converting the interference spectrum shifts of an FI sensing device into the corresponding variations of voltage signals. With many attractive features, e.g., simplicity, low cost, and reliable remote-monitoring, the proposed scheme is very suitable for practical applications.
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Wang, Hui, Lei Liang, Xiongbing Zhou, and Bin Tu. "New Fiber Bragg Grating Three-Dimensional Accelerometer Based on Composite Flexure Hinges." Sensors 21, no. 14 (July 9, 2021): 4715. http://dx.doi.org/10.3390/s21144715.
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Multi-dimensional acceleration sensors are used in important applications in the aerospace, weapon equipment, and nuclear fields and have strict requirements in terms of performance, volume, and mass. Fiber Bragg grating acceleration sensors use optical wavelength signals as a medium for information transmission to effectively eliminate the influence of electromagnetic interference between multi-dimensional sensors. In this study, we designed a composite flexure hinge three-dimensional acceleration sensor. To this end, we investigated the coupling mechanism between a new integrated elastomer structure and fiber grating to determine the influence of structural parameters on the static and dynamic characteristics, volume, and mass of the sensor. By optimizing the strain distribution, amplitude, and frequency and coupling characteristics between dynamic dimensions, a design theory and a method for integrating the three-dimensional acceleration sensor were developed. The size of the optimized accelerometer is only 25 mm × 25 mm × 30 mm. Performance testing revealed that, along the three spatial dimensions, the sensor had sensitivities of 51.9, 39.5, and 20.3 pm/g, respectively, resonance frequencies of 800, 1125, and 1750 Hz, respectively, and a measurable frequency range of 0–250 Hz.
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Ali, Burhan, and Mike Marshall. "Automated Optical Inspection (AOI) for FOPLP with Simultaneous Die Placement Metrology." International Symposium on Microelectronics 2019, no. 1 (October 1, 2019): 000203–10. http://dx.doi.org/10.4071/2380-4505-2019.1.000203.
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Abstract As the final step of IC fabrication, packaging is the process to encapsulate the chip and provide the interconnections for the I/O of the final form factor. The demand for increasingly higher I/O density, shrinking device size and lower cost that drive wafer processing also apply to the packaging process. Various technologies have been developed in order to achieve these goals with most of them being wafer-level packaging (WLP). Unlike traditional packaging process, most I/O interconnections are done at the wafer-level with redistribution layers (RDLs). RDLs are the layer where copper lines and vias form the electrical connections. Depending on the applications' market such as mobile, memory or the Internet of Things (IoT), fan-out wafer level packaging (FOWLP) provides the most promising method to support the I/O density requirements and fine RDL line/space. Moreover, fan-out panel level packaging (FOPLP) was also developed in order to capitalize on economies of scale and optimize substrate utilization. In this technology, a rectangular substrate is used in the process instead of a round-shape substrate like a wafer. Processes and equipment have long been developed for the wafer substrate market, but the previous developments cannot be directly applied to panel substrates. For instance, in the wafer line, spin on processes are very prevalent but these are not at all practical for a panel line. Some capital equipment manufacturers have been reluctant to embrace panel-level manufacturing due to the uncertainty as to whether it will prevail. Struggles with yield have been very common; some of which are due to die placement and others due to the lack of process control capabilities. With the explosion and adoption of FOWLP to enhance package shrinkage and performance the panel market becomes more and more viable. The companies that have embraced panel level manufacturing from the beginning have a distinct advantage due to their intimate knowledge and experience with the substrates as well as the relationship developed with capital equipment suppliers to develop the necessary technology in order to process the panels. However, there is still a great need to ensure the product mix deployed in panel form can have an acceptable yield; automated optical inspection and die placement metrology bridge that gap. Automated optical inspection allows for defect detection with traditional bright field (BF) or dark field (DF) illumination and also a new novel illumination technique that enables the detection of organic particles and/or residues that are often used in panel-level packaging processes. A system capable of macro defect detection with sub-micron capabilities allows for multi-purpose panel inspections. The system is also equipped with metrology capabilities for critical dimension and die placement measurements which meet the process node dimensional requirements. These features allow for process control of pick and place, overlay as well as feed-forward capabilities for die placement corrections. In a FOWLP/FOPLP process, chip first and chip last can be concluded among all available methods in the market. Die placement either start from the initial phase of the process or in the final phase of the process. In the chip first scenario, the chips are placed on a carrier by a pick-and-place system and then followed by an encapsulating molding process to reconstitute a substrate (reconstituted wafer or reconstituted panel). At this point a semi-additive process (SAP) is typically followed which includes a photo resist layer being coated, exposed and developed following copper (Cu) plating in order to form the redistribution layer. In this workflow, the die position are dominated by the accuracy of the pick-and-place tool and coefficient of thermal expansion (CTE) mismatch of the molding material and carrier. The trade-off between throughputs, placement accuracy and a feedback mechanism is the main impact from the pick-and-place tool in this process step. This affects both the chip first and chip last scenarios. The thermal expansion of the molding process not only adds additional die shift but also causes warpage of the reconstituted substrate that becomes an issue for automated handling systems and local process variation. Therefore, to know the actual die position and orientation after the die placement and molding process is crucial for matching with the following redistribution layers development. In one scenario it is possible to utilize the lithography system to perform die position metrology, however, this is time consuming and impacts the cost of ownership and overall throughput for the lithography process. A solution to this problem is provided by implementation of an optical metrology system. Since this information needs to be passed to the lithography tool in a usable manner for variable exposure positioning, the alignment of the stage coordinate system between the die metrology tool and lithography tool is a key point to ensure the correctness of the feed forward loop. For RDL development overlay between die and RDL via directly impact yield and are just as critical to the process as defect inspection and critical dimension measurements. Based on the corrections for each die, a yield prediction can be made and provides different strategies for the lithography tool's exposure field in order to balance throughput and exposure yield rate. In this paper, we demonstrate a solution using an automatic optical inspection (AOI) system to perform the die metrology for chip placement and RDL development in FOPLP and FOWLP. This includes die shift, die rotation, RDL inspection as well as the overlap between a reconstituted substrate and RDLs. This solution provides comprehensive coverage for packaging process control and significantly impacts yield optimization and throughput enhancement. With a multifunctional AOI system, it also reduces the cost of ownership for packaging processes.
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Amaki, Keisuke, Yukio Maeda, Tomohiro Iida, Kazuya Kato, Hideaki Tanaka, Takanori Yazawa, and Tatsuki Otsubo. "Influence of Scratch Marks on Undeformed Chip Thickness in Ultra-Precision Cutting of Al-Mg Alloys." Key Engineering Materials 749 (August 2017): 27–32. http://dx.doi.org/10.4028/www.scientific.net/kem.749.27.
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Recently, high efficiency and performance have become necessary attributes of information equipment such as laser printers. Thus, demand has increased for optical scanning parts that reduce optical aberration, scatter, and diffraction are required in laser printers. Polygon mirrors are manufactured by polishing a plating or glassy material to a mirror finish. In this study, we shortened the manufacturing process to improve the productivity and ultra-precision cutting technology of polygon mirrors made of aluminum. Thus, we had to reduce the geometric surface roughness achieved by mirror-cutting Al-Mg alloy and remove tear-out and scratch marks that occur during the cutting process. We investigated the cutting edge shape by using a straight diamond tool to decrease the surface defects produced during the ultra-precision cutting of Al-Mg alloy. We examined the mechanism for the occurrence of scratch marks and a method to reduce them. First, we measured the shape of the scratch marks and the cross-section with a scanning electron microscope. We found the tool collides with crystallization to produce small pieces, which then cause scratch marks. We developed a triple-facet tool with a double-facet at the end cutting edge to remove scratch marks and investigated the influence of surface defects. We clarified that using the triple-facet for a tool setting angle of 0° to 0.04° could achieve a good-quality machined surface without tear-out and scratch marks. In addition, the undeformed chip thickness was less than 80 nm
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You, Chen, Hao Ran Zheng, Dan Dan Jin, Lei Wang, Meng Meng Wang, and Min Fang Chen. "Influence of HA and Environmental Factors to the Damping Performance of HA/Mg-3Zn-0.5Zr Composites." Materials Science Forum 849 (March 2016): 416–23. http://dx.doi.org/10.4028/www.scientific.net/msf.849.416.
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Vibration and noise are the dangers for equipment, human health and environment. Developing of a new Mg matrix composite with high damping performance and high strength rate has been acknowledged as an important approach for the reduction of vibrations and prevention of noise. In this paper, xHA/Mg-3Zn-0.5Zr (x=0.5wt.%, 1wt.%, 1.5wt.%) composites were prepared by vacuum induction melting and hot extruding. The microstructure and damping performance were observed and measured using an optical microscope and a dynamic thermomechanical analysis apparatus (DMA), respectively. The influence of HA and environmental factors (temperature, frequency and strain amplitude) on the damping performance of HA/Mg-3Zn-0.5Zr composites were studied. The results showed that the damping performance of HA/Mg-3Zn-0.5Zr composites increased with increasing HA content and strain amplitude. The damping mechanism was in line with the G-L theory and interface damping theory. The damping values were strongly amplified at 150-300°C. The plot of damping versus temperature showed a peak for the Mg-3Zn-0.5Zr-1HA composite at 235°C. The low frequency damping values of xHA/Mg-3Zn-0.5Zr were higher than the high frequency damping values. It is suggested that the change of damping by a variety of external factors is due to the presence of different dominant damping mechanism at different conditions. Furthermore, it was found that at increased HA content, the grain size of HA/Mg-3Zn-0.5Zr composites decreased and the tensile strength and elongation of HA/Mg-3Zn-0.5Zr composites improved. This work will be beneficial for the study of Mg based joint implant materials with high vibration damping performance.
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Ikawati, Ratna, Widy Wibisono, Mulia F. Nasution, and Ade Y. Prasetya. "EARLY WARNING TERHADAP INSIDEN KEBAKARAN PADA OVER LAND BELT CONVEYOR PABRIK SEMEN MENGGUNAKAN LINEAR HEAT DETECTION SYSTEM." JURNAL EKONOMI BISNIS DAN KEWIRAUSAHAAN 9, no. 1 (June 25, 2020): 1. http://dx.doi.org/10.47942/iab.v9i1.641.
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The cement market is increasingly competitive with the rise of imported cement, which of course must be answered by cement producers among competition. One of the main processes that should not be disturbed is the supply of limestone from quarry to the factory. The safety of people, processes and equipment are certainly necessity for the production process to run smoothly. The problem that can occur in limestone supply is a breakdown on the Overland Belt Conveyor (OLBC) which is caused by a broken roller and causes the belt to tear and potentially fire. For this reason, prevention efforts need to be done with an early warning mechanism to provide alerts to interested parties. Early warning system can be applied to the process because it can detect the beginning of heat so that fires can be prevented. Therefore, it is necessary to install a sensor using optical fiber called a linear heat detector (LHD) on OLBC. Installing the LHD system on OLBC can effectively detect an increase in roller temperature which then becomes an early warning for operators in the control room 24 hours a day to prevent incidents that cause harm to the company due to belt fires or torn belts.
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Choi, Ahnryul, Hyunwoo Jung, Hyunggun Kim, and Joung Hwan Mun. "Predicting Center of Gravity Displacement During Walking Using a Single Inertial Sensor and Deep Learning Technique." Journal of Medical Imaging and Health Informatics 10, no. 6 (June 1, 2020): 1436–43. http://dx.doi.org/10.1166/jmihi.2020.3067.
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Center of gravity (CG) trajectory during walking has been used as an important indicator to understand the mechanism of pathological walking. Kinematic method using optical motion analysis system and force plate method using ground reaction force are conventionally used to calculate CG trajectory during gait. However, there is a limitation in that expensive experimental equipment is needed to measure it. The purpose of this study was to develop a long short-term memory (LSTM) network model that could estimate the CG trajectory during gait based on a low-cost portable inertial sensor signal. Twenty healthy adult males (age: 24.2±2.1 years; height: 171.4±5.2 cm; weight: 67.5±7.4 kg) who had no history of musculoskeletal disorders were participated in the study. Based on the optical motion capture system, CG trajectories have been calculated using highly accurate kinematic method. Input variables of the LSTM model consisted of a total of six signals of three-axis acceleration and angular velocity. Data were divided into training/validation/testing data at a ratio of 80/10/10. Performance was evaluated utilizing 10-fold cross-validation. As a result of model estimation, the Pearson correlation coefficient of about 0.9 or more and root mean square error values ranging from 3.9 to 31 mm were obtained in anterior/posterior, proximal/distal, and medial/lateral directions. These results confirmed that the CG trajectory during walking could be estimated by using low cost, small wearable inertial sensor. This novel CG prediction method has potential to evaluate pathological gait by incorporating patient walking data.
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Lin, Xiu Zhou, Min Hao Zhu, Zhen Bing Cai, J. F. Zheng, and Jin Fang Peng. "Microstructure and Reciprocating Sliding Tribological Performance of Micro-Arc Oxidation Coating Prepared on Al-Si Alloy." Advanced Materials Research 97-101 (March 2010): 1518–26. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.1518.
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Micro-arc oxidation coatings were prepared on Al-Si alloys surface by using a self-made micro-arc oxidation equipment. Its characterizations were systematically detected by Vickers hardness tester, profilometer, scanning electron microscope (SEM), energy dispersive X-ray spectrum (EDX), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). Reciprocating sliding tribological tests without lubricant of the micro-arc oxidation coating and its substrate alloy have been carried out under normal load of 5 N and displacement amplitudes of 2 mm. Dynamic analyses in combination with microscopic examinations were performed in detail through optical microscope (OM), SEM and EDX. The experimental results indicated that the MAO coating, with rough surface, high hardness and typical porous ceramic structure, is mainly consist of Al2O3, SiO2 and Al2SiO5 phases. The elementary substance Si and Al are not presented nearly on surface of coatings since the alloy is oxidated adequately during the micro arc oxidation process. Three stages can be observed in the friction coefficient curves both for the MAO coating and its substrate. The COF of the substrate was very low in initial stage, then a rapid ascend to a higher level and fluctuated in a larger range. But for the MAO coating, since its higher hardness and rough surface, the COF was higher than its substrate in initial stage. After a gradually ascent stage, the COF reached a steady state with a small range fluctuation and higher values. The wear mechanism for Al-Si alloy was main adhesive wear, abrasive wear, delamination and slight oxidative wear. After the micro-arc oxidation, the wear resistance of Al-Si alloy was greatly improved, and the wear mechanism of the MAO coating was the combination of delamination, abrasive wear, slight oxidative wear and some material transferred from the ball specimen.
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Jo, Euije, Dongwan Kim, and Jae-Young Leem. "Facile Synthesis of ZnO Thin Films at Low Temperatures Using an Additive-Free Electrochemical Oxidation Method." Korean Journal of Metals and Materials 58, no. 9 (September 5, 2020): 645–52. http://dx.doi.org/10.3365/kjmm.2020.58.9.645.
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Because of their simplicity and low equipment costs, various oxidation methods can be used to create metal oxides, but they still require long processing times and/or high temperatures. In this study, a new electrochemical oxidation (ECO) method, which oxidizes metal in DI water with a constant flowing current to both the cathode and anode, was developed to overcome the disadvantages of conventional oxidation methods. The mechanism of the ECO method is discussed. Metallic Zn films were oxidized by the ECO method in DI water for 1 h. The DI water temperature was varied from 30 to 90 <sup>o</sup>C to determine the optimal temperature for the ECO process. Increasing the temperature of the DI water led to distinct surface changes in the disk-shaped Zn plate. The intensity of diffraction peaks from the ZnO (002) plane gradually increased from 31.67 to 2806.48. The structural and optical properties of the ZnO thin film were enhanced as the temperature of the DI water approached 90 <sup>o</sup>C, which means that a high-quality ZnO thin film was synthesized using the ECO method at lower temperatures and shorter processing time compared with established oxidation methods. These results confirm the ECO method can be useful for the low-cost fabrication of transparent and flexible optoelectronic devices.
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Kudryavtsev, A. S., and K. A. Okhapkin. "Effect of long-term thermal aging in heat exchange equipment of fast neutron switchgears on the structure and properties of austenitic chromium-nickel steel." Izvestiya Visshikh Uchebnykh Zavedenii. Chernaya Metallurgiya = Izvestiya. Ferrous Metallurgy 61, no. 11 (December 24, 2018): 907–13. http://dx.doi.org/10.17073/0368-0797-2018-11-907-913.
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The influence of long-term operation at 515 °C on structure and properties of 09Cr18Ni9 steel was investigated. Structure and phase composition were obtained using optical and scanning electron microscopy. The phase composition of the steel in equilibrium state was determined by thermodynamic modeling in the software package Fact-Sage. As a result of the study, it was found that during the operation at 515 °C with a duration of 195,000 h, the structure changes occurred in the 09Cr18Ni9 steel with the formation of secondary phases, initiated by the release of elements with limited solubility from the supersaturated solid solution. The following secondary precipitates in structure of the solid solution of austenite presented: Cr23C6 chromium carbide, ferrite (a), G-phase. Based on comparison of the thermodynamic modeling results and on experimental determination of the phase composition, it was established that the steel structure is in a state close to equilibrium. The mechanism of structural transformations course and sequence of the secondary phases’ formation were revealed and described. At the initial stage, chromium carbide is formed, then a-ferrite is formed near the carbides, and then G-phase is formed. Results of the tests for impact strength and static elongation have shown that the change in phase composition in process of thermal aging leads to embrittlement of the steel - a reduction in ductility and impact energy. Fractografic studies of fracture surfaces of the samples have shown that the decrease in plasticity during long-term high-temperature operation is associated with softening of the grain body and strengthening of the boundaries due to secondary precipitations of the carbide phase. As a result of this process, plastic deformation is localized in the weakened volume of the body of grain surrounded by strong boundaries. The structure evolution during prolonged heat aging has the greatest effect on impact strength. At the same time, the change in ultimate and yield stress is insignificant. The main contribution to the change in mechanical characteristics of steel is made by the secondary precipitates of the carbide phase.