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1
Fang, Kun, Chengyin Liu i Jun Teng. "Cluster-based optimal wireless sensor deployment for structural health monitoring". Structural Health Monitoring 17, nr 2 (3.02.2017): 266–78. http://dx.doi.org/10.1177/1475921717689967.
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A well-designed wireless sensor deployment method not only directly influences the number of deployed sensors and data accuracy, but also influences on network topology. As most of the energy cost comes from the transmission and receiving of data packets, clustering optimization in wireless sensor network becomes an important issue for energy-efficient coordination among the densely deployed nodes for data communication. In a typical hierarchical wireless sensor network, total intra-cluster communication distance and total distance of cluster heads to base station depend on number of cluster heads. This work presents a novel approach by selecting the number of clusters in hierarchical wireless sensor network. We analyze and demonstrate the validity of the cluster optimization for wireless sensor deployment using an example of a numerically simulated simply supported truss, in terms of efficient use of the constrained wireless sensor network resources. Followed by a cluster-based optimization framework, we show how to adopt our approach to achieve scalable and efficient deployment, through a comprehensive optimization study of a realistic wireless structural health monitoring system. Finally, we suggest optimal deployment scheme based on the comparative performance evaluation results in the case study.
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Quan, Lue, Yuki Shimizu, Ryo Sato, Dong Wook Shin, Hiraku Matsukuma, Andreas Archenti i Wei Gao. "Design and Testing of a Compact Optical Angle Sensor for Pitch Deviation Measurement of a Scale Grating with a Small Angle of Diffraction". International Journal of Automation Technology 16, nr 5 (5.09.2022): 572–81. http://dx.doi.org/10.20965/ijat.2022.p0572.
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The design and testing of different optical heads were performed to evaluate the pitch deviation of a diffraction scale grating with a small diffraction angle. Based on the proposed pitch deviation evaluation method employing optical angle sensors based on laser autocollimation, a modified optical head with position-sensitive detectors (PSDs) is first designed and constructed by following the conventional optical configuration. Owing to the small angle of diffraction of the first-order diffracted beams, the modified optical head has a large working distance, resulting in poor sensor stability. Therefore, a novel and compact optical head employing a pair of small prisms is designed and developed to shorten the working distance of the optical head. An additional modification was also made to the developed compact optical head in such a way that collimator objectives (COs) in the laser autocollimation units are removed to improve the sensor sensitivity. Experimental comparisons were conducted using the three types of optical heads to verify the feasibility of the developed optical angle sensor with PSDs.
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Masunaga, Seiji, i Kenzo Nonami. "Controlled Metal Detector Mounted on Mine Detection Robot". International Journal of Advanced Robotic Systems 4, nr 2 (1.06.2007): 26. http://dx.doi.org/10.5772/5692.
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Landmine detection capability of metal detectors is very sensitive to the gap between buried landmines and the sensor heads. Therefore, human deminers manually scan ground surface with the metal detectors in such a manner that the sensor heads follow the ground surface. In case of robots assisted landmine detection, this function can be performed accurately and safely by controlling the gap and attitude of the sensor heads. In this investigation, the effectiveness of the gap and attitude control of the sensor head by some mechanical manipulator on the landmine detection performance has been addressed quantitatively. To this end, the paper describes the development of a Controlled Metal Detector (CMD) for controlling the gap and attitude of the sensor head. The CMD generates trajectories of the sensor head from the depth information of the ground surface acquired with 3-D stereovision camera in order to avoid any obstacles and possible impact with the ground, and then tracks the trajectories with a trajectory-tracking controller. The effectiveness and the impact related to the gap and attitude control on the landmine detection performance of the CMD have been demonstrated by experimental studies.
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Li, Yufeng, i Aric R. Kumaran. "The Determination of Flash Temperature in Intermittent Magnetic Head/Disk Contacts Using Magnetoresistive Heads: Part I—Model and Laser Simulation". Journal of Tribology 115, nr 1 (1.01.1993): 170–78. http://dx.doi.org/10.1115/1.2920972.
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The feasibility of using a magnetoresistive magnetic head to determine the flash temperature of intermittent magnetic head/disk contacts is investigated. A finite difference model is developed to study the effects of the magnetoresistive sensor height, the contact power intensity and the contact duration on the temperature response characteristics of the magnetoresistive sensor. A pulsed neody-minum:yttrium-aluminum-garnet laser is used as the heat source to simulate the contact and verify the model. The simulation results agree well with the theoretical model. Based on the theoretical model and laser simulation, a temperature sensitivity coefficient ζ is proposed to determine the surface temperature rise.
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Gatzen, Hans H., Norman Muenter, Binghe Ma i Caspar Morsbach. "Thermal sensor for in situ flying height measurements of optical flying heads". Tribology International 38, nr 6-7 (czerwiec 2005): 594–98. http://dx.doi.org/10.1016/j.triboint.2005.01.020.
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Li, Yufeng, i Aric R. Kumaran. "The Determination of Flash Temperature in Intermittent Magnetic Head/Disk Contacts Using Magnetoresistive Heads: Part II—Experimental Investigation". Journal of Tribology 115, nr 1 (1.01.1993): 179–84. http://dx.doi.org/10.1115/1.2920973.
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The flash temperature during intermittent head/disk contacts was measured using specially fabricated magnetoresistive heads. Microasperities were intentionally created on disk substrates, and ZrO2 was sputtered on disc surfaces as overcoat. It was found that with a disk spinning speed of 20 m/s, flash temperature could reach 50 to 100°C for transient contact (head was moving in disk radial direction), but less than 40°C for dwell on track contact (head was stationary). The contact times were in the range from submicroseconds to several microseconds, contact widths on the order of several micrometers, and temperature sensitivity coefficients in the range from 0.15 to 0.7 for a 2.5–μ high magnetoresistive sensor.
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K, Ramesh, Renjith P. N, M. AntoBennet i S. Balasubramani. "Certain Investigation on Improved Cluster Protocol with Trust security for Wireless Sensor Networks". International Journal of Electrical and Electronics Research 10, nr 4 (30.12.2022): 1043–49. http://dx.doi.org/10.37391/ijeer.100447.
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Immense development of Micro Electro Mechanical Systems (MEMS) made an incredible advancement in wireless technology. The Wireless Sensor Network (WSN) has created many opportunities for the development of various applications in the fields of military, research, medical, engineering, etc. In this research article, a novel trust-based energy-aware clustering protocol is proposed. The clustering algorithm concentrates on reducing the time spent on cluster formation, controlling redundant data forwarding, and prolonging the network's lifespan. In this model, clustered nodes are classified into three levels like Cluster heads (CH), secondary CHs, and sensor nodes (SN) are used to sense the environmental changes and report to the Base Station (BS). An extension of the lifetime of a WSN is possible by the use of secure multi-hop routing with an aggregation technique to forward data from a cluster to the BS. Compared to relevant works on clustering with the routing protocol, the simulation result showed improved energy efficiency and network lifetime.
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Zabihi-Hesari, Alireza, Saeed Ansari-Rad, Farzad A. Shirazi i Moosa Ayati. "Fault detection and diagnosis of a 12-cylinder trainset diesel engine based on vibration signature analysis and neural network". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, nr 6 (3.06.2018): 1910–23. http://dx.doi.org/10.1177/0954406218778313.
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This paper presents a condition monitoring and combustion fault detection technique for a 12-cylinder 588 kW trainset diesel engine based on vibration signature analysis using fast Fourier transform, discrete wavelet transform, and artificial neural network. Most of the conventional fault diagnosis techniques in diesel engines are mainly based on analyzing the difference of vibration signals amplitude in the time domain or frequency spectrum. Unfortunately, for complex engines, the time- or frequency-domain approaches do not provide appropriate features solely. In the present study, vibration signals are captured from both intake manifold and cylinder heads of the engine and were analyzed in time-, frequency-, and time–frequency domains. In addition, experimental data of a 12-cylinder 588 kW diesel engine (of a trainset) are captured and the proposed method is verified via these data. Results show that power spectra of vibration signals in the low-frequency range reliably distinguish between normal and faulty conditions. However, they cannot identify the fault location. Hence, a feature extraction method based on discrete wavelet transform and energy spectrum is proposed. The extracted features from discrete wavelet transform are used as inputs in a neural network for classification purposes according to the location of sensors and faults. The experimental results verified that vibration signals acquired from intake manifold have more potential in fault detection. In addition, the capacity of discrete wavelet transform and artificial neural network in detection and diagnosis of faulty cylinders subjected to the abnormal fuel injection was revealed in a complex diesel engine. Beside condition monitoring of the engine, a two-step fault detection method is proposed, which is more reliable than other one-step methods for complex engines. The average condition monitoring performance is from 93.89% up to 99.17%, based on fault location and sensor placement, and the minimum classification performance is 98.34%.
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Zhang, Yuntao, Wenge Wu, Yanwen Han, Haijun Wen, Yunping Cheng i Lijuan Liu. "Design and Analysis of a Turning Dynamometer Embedded in Thin-Film Sensor". Micromachines 10, nr 3 (26.03.2019): 210. http://dx.doi.org/10.3390/mi10030210.
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This paper proposes a high-strain sensitivity turning dynamometer that combines several thin-film resistor grids into three Wheatstone full-bridge circuits that can measure triaxial cutting forces. This dynamometer can replace different cutter heads using flange connections. In order to improve the strain effect of the dynamometer, the strain film sensor is fixed on the regular octagonal connection plates on both ends of the elastomer by vacuum brazing, and the stepped groove structure is also designed inside the elastomer. The dynamometer model is simplified as a four-segment cantilever beam which has different sections. The measurement mechanism model of the dynamometer system is established by the transformation relationship between deflection and strain, under external force. The standard turning tool of 20 mm square is used as a reference. The influence of the structural dimensions of the dynamometer on its strain sensitivity coefficient K is studied. The applicability of the theoretical model of dynamometer strain is verified by finite element analysis. Finally, the dynamometer with the largest K value is subjected to the bending test and compared with a standard turning tool. The experimental results show that the measurement sensitivity of the dynamometer is 2.32 times greater than that of the standard turning tool. The results also show that this dynamometer can effectively avoid the influence of the pasting process on strain transmission, thus indicating its great potential for measuring cutting force in the future.
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Guo, Zhihui, Hongbin Chen i Shichao Li. "Deep Reinforcement Learning-Based One-to-Multiple Cooperative Computing in Large-Scale Event-Driven Wireless Sensor Networks". Sensors 23, nr 6 (18.03.2023): 3237. http://dx.doi.org/10.3390/s23063237.
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Emergency event monitoring is a hot topic in wireless sensor networks (WSNs). Benefiting from the progress of Micro-Electro-Mechanical System (MEMS) technology, it is possible to process emergency events locally by using the computing capacities of redundant nodes in large-scale WSNs. However, it is challenging to design a resource scheduling and computation offloading strategy for a large number of nodes in an event-driven dynamic environment. In this paper, focusing on cooperative computing with a large number of nodes, we propose a set of solutions, including dynamic clustering, inter-cluster task assignment and intra-cluster one-to-multiple cooperative computing. Firstly, an equal-size K-means clustering algorithm is proposed, which activates the nodes around event location and then divides active nodes into several clusters. Then, through inter-cluster task assignment, every computation task of events is alternately assigned to the cluster heads. Next, in order to make each cluster efficiently complete the computation tasks within the deadline, a Deep Deterministic Policy Gradient (DDPG)-based intra-cluster one-to-multiple cooperative computing algorithm is proposed to obtain a computation offloading strategy. Simulation studies show that the performance of the proposed algorithm is close to that of the exhaustive algorithm and better than other classical algorithms and the Deep Q Network (DQN) algorithm.
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Kemper, G., B. Melykuti i C. Yu. "CALIBRATION PROCEDURES ON OBLIQUE CAMERA SETUPS". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (3.06.2016): 205–9. http://dx.doi.org/10.5194/isprsarchives-xli-b1-205-2016.
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Beside the creation of virtual animated 3D City models, analysis for homeland security and city planning, the accurately determination of geometric features out of oblique imagery is an important task today. Due to the huge number of single images the reduction of control points force to make use of direct referencing devices. This causes a precise camera-calibration and additional adjustment procedures. <br><br> This paper aims to show the workflow of the various calibration steps and will present examples of the calibration flight with the final 3D City model. In difference to most other software, the oblique cameras are used not as co-registered sensors in relation to the nadir one, all camera images enter the AT process as single pre-oriented data. This enables a better post calibration in order to detect variations in the single camera calibration and other mechanical effects. <br><br> The shown sensor (Oblique Imager) is based o 5 Phase One cameras were the nadir one has 80 MPIX equipped with a 50 mm lens while the oblique ones capture images with 50 MPix using 80 mm lenses. The cameras are mounted robust inside a housing to protect this against physical and thermal deformations. The sensor head hosts also an IMU which is connected to a POS AV GNSS Receiver. The sensor is stabilized by a gyro-mount which creates floating Antenna –IMU lever arms. They had to be registered together with the Raw GNSS-IMU Data. <br><br> The camera calibration procedure was performed based on a special calibration flight with 351 shoots of all 5 cameras and registered the GPS/IMU data. This specific mission was designed in two different altitudes with additional cross lines on each flying heights. The five images from each exposure positions have no overlaps but in the block there are many overlaps resulting in up to 200 measurements per points. On each photo there were in average 110 well distributed measured points which is a satisfying number for the camera calibration. In a first step with the help of the nadir camera and the GPS/IMU data, an initial orientation correction and radial correction were calculated. With this approach, the whole project was calculated and calibrated in one step. During the iteration process the radial and tangential parameters were switched on individually for the camera heads and after that the camera constants and principal point positions were checked and finally calibrated. <br><br> Besides that, the bore side calibration can be performed either on basis of the nadir camera and their offsets, or independently for each camera without correlation to the others. This must be performed in a complete mission anyway to get stability between the single camera heads. Determining the lever arms of the nodal-points to the IMU centre needs more caution than for a single camera especially due to the strong tilt angle. <br><br> Prepared all these previous steps, you get a highly accurate sensor that enables a fully automated data extraction with a rapid update of you existing data. Frequently monitoring urban dynamics is then possible in fully 3D environment.
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Kemper, G., B. Melykuti i C. Yu. "CALIBRATION PROCEDURES ON OBLIQUE CAMERA SETUPS". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (3.06.2016): 205–9. http://dx.doi.org/10.5194/isprs-archives-xli-b1-205-2016.
Pełny tekst źródłaStreszczenie:
Beside the creation of virtual animated 3D City models, analysis for homeland security and city planning, the accurately determination of geometric features out of oblique imagery is an important task today. Due to the huge number of single images the reduction of control points force to make use of direct referencing devices. This causes a precise camera-calibration and additional adjustment procedures. <br><br> This paper aims to show the workflow of the various calibration steps and will present examples of the calibration flight with the final 3D City model. In difference to most other software, the oblique cameras are used not as co-registered sensors in relation to the nadir one, all camera images enter the AT process as single pre-oriented data. This enables a better post calibration in order to detect variations in the single camera calibration and other mechanical effects. <br><br> The shown sensor (Oblique Imager) is based o 5 Phase One cameras were the nadir one has 80 MPIX equipped with a 50 mm lens while the oblique ones capture images with 50 MPix using 80 mm lenses. The cameras are mounted robust inside a housing to protect this against physical and thermal deformations. The sensor head hosts also an IMU which is connected to a POS AV GNSS Receiver. The sensor is stabilized by a gyro-mount which creates floating Antenna –IMU lever arms. They had to be registered together with the Raw GNSS-IMU Data. <br><br> The camera calibration procedure was performed based on a special calibration flight with 351 shoots of all 5 cameras and registered the GPS/IMU data. This specific mission was designed in two different altitudes with additional cross lines on each flying heights. The five images from each exposure positions have no overlaps but in the block there are many overlaps resulting in up to 200 measurements per points. On each photo there were in average 110 well distributed measured points which is a satisfying number for the camera calibration. In a first step with the help of the nadir camera and the GPS/IMU data, an initial orientation correction and radial correction were calculated. With this approach, the whole project was calculated and calibrated in one step. During the iteration process the radial and tangential parameters were switched on individually for the camera heads and after that the camera constants and principal point positions were checked and finally calibrated. <br><br> Besides that, the bore side calibration can be performed either on basis of the nadir camera and their offsets, or independently for each camera without correlation to the others. This must be performed in a complete mission anyway to get stability between the single camera heads. Determining the lever arms of the nodal-points to the IMU centre needs more caution than for a single camera especially due to the strong tilt angle. <br><br> Prepared all these previous steps, you get a highly accurate sensor that enables a fully automated data extraction with a rapid update of you existing data. Frequently monitoring urban dynamics is then possible in fully 3D environment.
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Lamassoure, Léo, Justine Giunta, Giuseppe Rosi, Anne-Sophie Poudrel, Romain Bosc i Guillaume Haïat. "Using an impact hammer to perform biomechanical measurements during osteotomies: Study of an animal model". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 235, nr 7 (23.04.2021): 838–45. http://dx.doi.org/10.1177/09544119211011824.
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Osteotomies are common surgical procedures used for instance in rhinoplasty and usually performed using an osteotome impacted by a mallet. Visual control being difficult, osteotomies are often based on the surgeon proprioception to determine the number and energy of each impact. The aim of this study is to determine whether a hammer instrumented with a piezoelectric force sensor can be used to (i) follow the displacement of the osteotome and (ii) determine when the tip of the osteotome arrives in frontal bone, which corresponds to the end of the osteotomy pathway. Seven New Zealand White rabbit heads were collected, and two osteotomies were performed on their left and right nasal bones using the instrumented hammer to record the variation of the force as a function of time during each impact. The second peak time τ was derived from each signal while the displacement of the osteotome tip D was determined using video motion tracking. The results showed a significant correlation between τ and D ( ρ2 = 0.74), allowing to estimate the displacement of the osteotome through the measurement of τ. The values of τ measured in the frontal bone were significantly lower than in the nasal bone ( p<10−10), which allows to determine the transition between the nasal and frontal bones when τ becomes lower than 0.78 its initial averaged value. Although results should be validated clinically, this technology could be used by surgeons in the future as a decision support system to help assessing the osteotome environment.
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Wang, Song, i Zhixia Li. "Roadside Sensing Information Enabled Horizontal Curve Crash Avoidance System Based on Connected and Autonomous Vehicle Technology". Transportation Research Record: Journal of the Transportation Research Board 2673, nr 5 (22.03.2019): 49–60. http://dx.doi.org/10.1177/0361198119837957.
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Horizontal curves are a major cause of road departure crashes that lead to fatal and severe injuries. Existing curve crash avoidance systems are typically enabled by displaying safety messages via in-vehicle heads-up/down display. However, these systems just pass the information to drivers. The final decision to reduce or maintain speed in response to the safety message is still the human driver’s. Because of the involvement of the human factor, there is potential for road departure crashes to happen if human drivers do not respond to safety messages appropriately. Autonomous vehicle (AV) technology targets elimination of human error in driving through an automated driving system. In this context, this paper proposes a conceptual prototype of a connected and AV-based horizontal curve crash avoidance system (CAV-HCCAS), aiming at achieving a permanent solution to horizontal curve safety by excluding human error through automated driving. In CAV-HCCAS, a roadside sensor detects pavement wetness level at the horizontal curve and communicates it to the vehicle via dedicated short-range communication. By processing the pavement wetness information, the AV applies a safe curve travel speed that reflects the real-time pavement conditions. An automated driving simulation experiment was performed to prove the concept. Dry and wet pavement conditions were simulated for a horizontal curve. Lane deviation data and the resulting lane departure conflicts were measured as safety performance measures. Results indicate a significant reduction of lane departure conflicts when CAV-HCCAS is implemented under both dry and wet pavement conditions, which reflects a substantial safety benefit.
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Lee, Beom-Ryeol, José Gil Marichal-Hernández, José Manuel Rodríguez-Ramos, Wook-Ho Son, Sunghee Hong i Jung-Young Son. "Wavefront Characteristics of a Digital Holographic Optical Element". Micromachines 14, nr 6 (10.06.2023): 1229. http://dx.doi.org/10.3390/mi14061229.
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In this study, a 50 × 50 mm holographic optical element (HOE) with the property of a spherical mirror was recorded digitally on a silver halide photoplate using a wavefront printing method. It consisted of 51 × 96 hologram spots with each spot measuring 0.98 × 0.52 mm. The wavefronts and optical performance of the HOE were compared with those of reconstructed images from a point hologram displayed on DMDs of different pixel structures. The same comparison was also performed with an analog-type HOE for a heads-up display and with a spherical mirror. A Shack–Hartmann wavefront sensor was used to measure the wavefronts of the diffracted beams from the digital HOE and the holograms as well as the reflected beam from the analog HOE and the mirror when a collimated beam was incident on them. These comparisons revealed that the digital HOE could perform as a spherical mirror, but they also revealed astigmatism—as in the reconstructed images from the holograms on DMDs—and that its focusability was worse than that of the analog HOE and the spherical mirror. A phase map, i.e., the polar coordinate-type presentation of the wavefront, could visualize the wavefront distortions more clearly than the reconstructed wavefronts obtained using Zernike polynomials. The phase map revealed that the wavefront of the digital HOE was more distorted than those of the analog HOE and the spherical mirror.
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Tan, Fu Yang, Mohd Hasnun Arif Hassan, Nasrul Hadi Johari, Mohd Nadzeri Omar i Iskandar Hasanudin. "The Effect of Wearing Soccer Headgear on the Head Response in Soccer Heading". International Journal of Automotive and Mechanical Engineering 19, nr 4 (28.12.2022): 10112–20. http://dx.doi.org/10.15282/ijame.19.4.2022.08.0782.
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Soccer is regarded as the most popular sport in the world, with millions of people actively involved in the game. Being a contact sport in nature, soccer players are susceptible to various kinds of injuries, such as lower extremities muscle injury. In addition to those familiar injuries that soccer players sustain during the game, traumatic brain injury is also a possibility. Head impacts in soccer could be a result of head-to-head impact with an opponent player, a head-to-elbow impact, an impact with the goal post, an impact with the ground, as well as an impact with the soccer ball, which occurs during a heading manoeuvre. Soccer allows the players to use their heads to hit the ball to pass it to a teammate or even perform heading to score a goal. Although soccer heading is perceived as less harmful as compared to head impacts with other hard objects, many studies have shown compelling evidence that this repetitive heading might harm the brain, thereby leading to traumatic brain injury. Protective headgears designed especially for soccer players have been commercially available in the market for some years. However, the effectiveness of these headgears in reducing the impact due to soccer heading has not been well studied. This paper investigates the effectiveness of two commercially available headgears, the Full90 and the ForceField headgear by means of a heading experiment. An anthropometric test device known as Hybrid III head and neck dummy instrumented with an inertial sensor that consists of a triaxial accelerometer and gyroscope installed at the centre of gravity of the head was used in the experiment. A soccer ball launching machine was used to propel the ball at several inbound velocities. Peak linear acceleration (PLA) and peak angular acceleration (PRA) were recorded, and the head injury criterion (HIC) and the rotational injury criterion (RIC) were calculated. It was found that both headgears failed to reduce the linear components of head acceleration but instead increased the HIC (13 – 66% increment) depending on the inbound ball velocity. With respect to the rotational component of head injury, the Full90 headgear was found to reduce the RIC up to 29%, but the ForceField failed to provide a significant reduction of RIC. Overall, both headgears were found to be ineffective in reducing linear and rotational components of head injury, which could be attributed to the headgear design. Improved headgear design and an improved padded foam are needed to protect soccer player’s brain while performing soccer heading.
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Kuchynskyi, K. A., V. A. Kramarskyi, D. I. Hvalin i V. A. Mystetskyi. "STUDY OF PHYSICAL PROCESSES IN A TURBOGENERATOR END ZONE AT THE MECHANICAL DAMAGES OF STATOR CORE FASTENING". Praci elektrodinamiki Nacionalanoi akademii nauk Ukraini Institutu 2020, nr 57 (2.12.2020): 65–72. http://dx.doi.org/10.15407/publishing2020.57.065.
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With the help of mathematical simulation of mechanical processes in the stator core fastening system of a powerful turbogenerator end zone obtained appropriateness of basic parameters changes at the break of clamp prisms heads of the stator core. It is determined that the sudden break of one or more clamp prisms leads to longitudinal oscillation of their other working heads and stiff connected with them press plate, accordingly. Although such oscillation is insignificant but propagates along the entire surface of the press plate with a maximum value in the break zone and subsequent decrease with distance from this zone and therefore can be detected with the help of existing vibration sensors by installing them on the press plate. It is possible to use a limited number of sensors due to the propagation of vibration along the entire surface of the plate. But because the vibration changes are insignificant, in this case, there is a complexity of control that requires the use of high-sensitivity sensors and great informative computing equipment. According to the sensors indices, it is possible to determine the number of breaks for clamp prisms heads of the stator core and the number of them working heads, accordingly. Besides, this effect can be used to diagnose the un-compression of the stator core tooth zone. Since one of the important ways to improve the control and diagnostics of turbogenerators is the detection, the presence of such knowledge will allow making the optimal decision for further measures. References 8, figures 8, tables 2.
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Uebner, Michael, Richard W. Carr, Karl Messlinger i Roberto De Col. "Activity-dependent sensory signal processing in mechanically responsive slowly conducting meningeal afferents". Journal of Neurophysiology 112, nr 12 (15.12.2014): 3077–85. http://dx.doi.org/10.1152/jn.00243.2014.
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Activity-dependent processes in slowly conducting afferents have been shown to modulate conduction and receptive properties, but it is not known how the frequency of action potential firing determines the responses of such fibers to mechanical stimulation. We examined the responses of slowly conducting meningeal afferents to mechanical stimuli and the influence of preceding action potential activity. In hemisected rat heads with adhering cranial dura mater, recordings were made from meningeal nerves. Dural receptive fields of mechanically sensitive afferent fibers were stimulated with a custom-made electromechanostimulator. Sinusoidal mechanical stimuli of different stimulus durations and amplitudes were applied to produce either high-frequency (phasic) or low-frequency (tonic) discharges. Most fibers showed slowing of their axonal conduction velocity on electrically evoked activity at ≥2 Hz. In this state, the peak firing frequency of phasic responses to a 250-ms mechanical stimulus was significantly reduced compared with control. In contrast, the frequency of tonic responses induced by mechanical stimuli of >500 ms did not change. In a rare subtype of afferents, which showed conduction velocity speeding during activity, an increase in the phasic responses to mechanical stimuli was observed. Depending on the axonal properties of the afferent fibers, encoding of phasic components of mechanical stimuli is altered according to the immediate firing history. Preceding activity in mechanoreceptors slowing their conduction velocity seems to provide a form of low-pass filtering of action potential discharges predominantly reducing the phasic component. This may improve discrimination between harmless and potentially harmful mechanical stimuli in normal tissue.
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Cheng, Xiao, Chongzhi Bao, Xiaoming Wang i Wentao Dong. "Stretchable strain sensor based on conductive polymer for structural health monitoring of high-speed train head". Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, nr 3 (30.12.2019): 496–503. http://dx.doi.org/10.1177/1464420719896599.
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Stretchable strain sensor has been widely applied to structural health monitor in the aerospace, high-speed train, wear electronics, and civil engineering areas. Stretchable strain sensor based on PDMS-CB (polydimethylsiloxane carbon-black) conductive polymer with large deformability is designed to collect the structural health data of the curved surface of high-speed train head (HSTH). The stretchability (>30%) of the strain sensor is validated by the FEM simulation and experimental results. Temperature effect and fatigue analysis of PDMS-CB strain sensors are considered to compensate the accuracy of strain data. The stretchable strain sensor has been applied to detect the cracks of the curved surface via the variable strain data corresponding to the crack length. A structural health monitor (SHM) based on the PDMS-CB strain sensor array is built to collect the continuous long-term strain data of the curved surface of HSTH. Wind pressure is applied to the strain sensor onto the curved surface of HSTH as external signal to simulate the strain distribution. It has been demonstrated that the PDMS-CB strain sensor is applied to structural health monitor of HSTH effectively during the driving process.
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Lesiak, Piotr, Konrad Pogorzelec, Aleksandra Bochenek, Piotr Sobotka, Karolina Bednarska, Alicja Anuszkiewicz, Tomasz Osuch i in. "Three-Dimensional-Printed Mechanical Transmission Element with a Fiber Bragg Grating Sensor Embedded in a Replaceable Measuring Head". Sensors 22, nr 9 (28.04.2022): 3381. http://dx.doi.org/10.3390/s22093381.
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Compliant mechanisms have gained an increasing interest in recent years, especially in relation to the possibility of using 3D printers for their production. These mechanisms typically find applications in precise positioning systems of building robotic devices or in sensing where they can be used to characterize displacement. Three-dimensional printing with PLA materials allows fiber optic-based sensors to be incorporated into the structures of properly designed compliant mechanisms. Therefore, in this paper, an innovative technology is described, of a Fiber Bragg Grating (FBG) sensor embedded in a measuring head which was then inserted into a specially designed mechanical transmission element. The shape of this element is based on clippers that allow to freely modify the amplification of displacement amplitude so that the FBG sensor always works in the most optimal regime without any need to modify its external dimensions. Flexural sensitivity of the replaceable measuring head equal to 1.26 (mε/mm) can be adapted to the needs of the flexure design.
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DeGaspari, John. "MEMS' Rocky Road". Mechanical Engineering 124, nr 06 (1.06.2002): 38–41. http://dx.doi.org/10.1115/1.2002-jun-1.
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This article highlights that there is potential demand for microelectromechanical systems (MEMS) devices across a range of industries. In 2002, the five leading applications of MEMS will use 21.5 million disposable blood pressure sensors, 28.7 million manifold absolute pressure sensors for engines, 85 million packaged airbag accelerometers, 425 million inkjet printer heads, and a whopping 1.58 billion read/write magnetic heads for computer hard drives. In MEMS, process is driven by design, so it is important for companies seeking to commercialize a micro device to evaluate the capabilities of a foundry. Industry groups are starting to recognize standardization as an issue, and are focusing on fabrication. The MEMS Industry Group, a trade association based in Pittsburgh, identified standardization as a key challenge in its 2001 annual report. The Group plans to issue a report on foundries and fabrication sooner.
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Jagan, G. C., i P. Jesu Jayarin. "Wireless Sensor Network Cluster Head Selection and Short Routing Using Energy Efficient ElectroStatic Discharge Algorithm". Journal of Engineering 2022 (12.02.2022): 1–10. http://dx.doi.org/10.1155/2022/8429285.
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Wireless sensor networks attract so much attention in current IoT-enabled industrial and domestic applications having either homogeneous or heterogeneous sensors deployed to acquire information of intent. WSNs are designed to operate using self-powered sensor nodes as their choice of application is geographic critical. Such nodes must support energy efficiency so that network longevity becomes high. Cluster head selection plays a crucial stage in a WSN architecture which mainly focuses on the minimization of network energy consumption. It groups sensor nodes in such a way that a sophisticated network cluster is formed to have enhanced life time besides a low power consumption. A popular clustering technique, known as LEACH and its variants, is found to be energy efficient compared to its counterparts. The authors propose a novel fully connected energy efficient clustering (FCEEC) mechanism using the electrostatic discharge algorithm to establish a fully connected network with shortest path routing from sensor nodes (SNs) to cluster head (CH) in a multihop environment. The proposed electrostatic discharge algorithm (ESDA) enhances network life time while attaining energy efficient full connectivity between sensor nodes. As a result of ESD, the dead node count is reduced significantly so that the network longevity is increased. In the end, simulation results exhibited improved performance metrics such as energy efficiency, dead node count, packet delivery, and network latency compared to certain conventional CH selection approach.
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Lee, Jung-Ryul, i Hiroshi Tsuda. "A novel fiber Bragg grating acoustic emission sensor head for mechanical tests". Scripta Materialia 53, nr 10 (listopad 2005): 1181–86. http://dx.doi.org/10.1016/j.scriptamat.2005.07.018.
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KELEMEN, MICHAL, TATIANA KELEMENOVA, MARTIN VARGA, PETER JAN SINCAK, LUKAS LESTACH, ELENA SERGEEVNA BAYMETOVA, MARIA RAVILEVNA KOROLEVA i ALENA ALEKSEEVNA CHERNOVA. "HEAD ON HALL EFFECT SENSOR ARRANGEMENT FOR DISPLACEMENT MEASUREMENT". MM Science Journal 2021, nr 4 (13.10.2021): 4757–63. http://dx.doi.org/10.17973/mmsj.2021_10_2021026.
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Hall effect sensor is a very frequently used sensor in mechatronic products. There is little information in the catalogue sheets about the application possibilities of this type of sensor. This article examines the configuration options of this sensor and how to use it to achieve the best measurement uncertainty and minimal hysteresis.
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KELEMEN, MICHAL, TATIANA KELEMENOVA, MARTIN VARGA, PETER JAN SINCAK, LUKAS LESTACH, ELENA SERGEEVNA BAYMETOVA, MARIA RAVILEVNA KOROLEVA i ALENA ALEKSEEVNA CHERNOVA. "HEAD ON HALL EFFECT SENSOR ARRANGEMENT FOR DISPLACEMENT MEASUREMENT". MM Science Journal 2021, nr 4 (13.10.2021): 4757–63. http://dx.doi.org/10.17973/mmsj.2021_10_2021026.
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Hall effect sensor is a very frequently used sensor in mechatronic products. There is little information in the catalogue sheets about the application possibilities of this type of sensor. This article examines the configuration options of this sensor and how to use it to achieve the best measurement uncertainty and minimal hysteresis.
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Falland-Cheung, Lisa, J. Neil Waddell, Kai C. Li, Darryl C. Tong i Paul A. Brunton. "Anatomical head model to measure impact force transfer through the head layers and their displacement". Journal of Concussion 2 (styczeń 2018): 205970021877782. http://dx.doi.org/10.1177/2059700218777829.
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When the human head is subjected to blunt force impact, there are several mechanical responses that may result from the forces involved, including absorption of impact forces through the various layers of the head. The purpose of this study was to develop an anatomical head model to measure force transfer through the various head layers and their displacement when subject to short-duration high-velocity impacts. An anatomical head model was constructed using previously validated simulant materials: epoxy resin (skull), polyvinyl siloxane (scalp), agar/glycerol/water (brain) and modified intravenous fluid for the cerebrospinal fluid. An array of accelerometers (4 mm × 4 mm × 1.45 mm) was incorporated into the various layers of the head to measure forces in x- (anterior/posterior), y- (left/right) and z- (up/down) axis. All sensors were connected to a signal conditioning board and USB powered data loggers. The head model was placed into a rigid metal stand with an optical sensor to trigger data capturing. A weight (750 g) was dropped from a height of 0.5 m (n= 20). Impact forces (z-axis) of 1107.05 N were recorded on top of the skin, with decreasing values through the different layers (bottom of skin 78.48 N, top of skull 319.82 N, bottom of skull 87.30 N, top and centre of brain 47.09 N and base of brain 78.41 N. Forces in the x- and y-axes were similar to those of the z-axis. With the base of the brain still receiving 78.41 N, this highlights the potential danger of repetitive impact forces to the head. Upon impact the layers of the head are displaced in the x-, y- and z-direction, with the highest values shown in the z-axis. In conclusion, this study identified the importance of considering short-duration high-intensity impacts to the head and their effect on underlying tissues.
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Tiernan, Stephen, Gary Byrne i David Michael O’Sullivan. "Evaluation of skin-mounted sensor for head impact measurement". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 233, nr 7 (23.05.2019): 735–44. http://dx.doi.org/10.1177/0954411919850961.
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Weston, Angela R., Brian J. Loyd, Carolyn Taylor, Carrie Hoppes i Leland E. Dibble. "Head and Trunk Kinematics during Activities of Daily Living with and without Mechanical Restriction of Cervical Motion". Sensors 22, nr 8 (16.04.2022): 3071. http://dx.doi.org/10.3390/s22083071.
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Alterations in head and trunk kinematics during activities of daily living can be difficult to recognize and quantify with visual observation. Incorporating wearable sensors allows for accurate and measurable assessment of movement. The aim of this study was to determine the ability of wearable sensors and data processing algorithms to discern motion restrictions during activities of daily living. Accelerometer data was collected with wearable sensors from 10 healthy adults (age 39.5 ± 12.47) as they performed daily living simulated tasks: coin pick up (pitch plane task), don/doff jacket (yaw plane task), self-paced community ambulation task [CAT] (pitch and yaw plane task) without and with a rigid cervical collar. Paired t-tests were used to discern differences between non-restricted (no collared) performance and restricted (collared) performance of tasks. Significant differences in head rotational velocity (jacket p = 0.03, CAT-pitch p < 0.001, CAT-yaw p < 0.001), head rotational amplitude (coin p = 0.03, CAT-pitch p < 0.001, CAT-yaw p < 0.001), trunk rotational amplitude (jacket p = 0.01, CAT-yaw p = 0.005), and head–trunk coupling (jacket p = 0.007, CAT-yaw p = 0.003) were captured by wearable sensors between the two conditions. Alterations in turning movement were detected at the head and trunk during daily living tasks. These results support the ecological validity of using wearable sensors to quantify movement alterations during real-world scenarios.
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Chen, G., C. L. Tien, X. Wu i J. S. Smith. "Thermal Diffusivity Measurement of GaAs/AlGaAs Thin-Film Structures". Journal of Heat Transfer 116, nr 2 (1.05.1994): 325–31. http://dx.doi.org/10.1115/1.2911404.
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This work develops a new measurement technique that determines the thermal diffusivity of thin films in both parallel and perpendicular directions, and presents experimental results on the thermal diffusivity of GaAs/AlGaAs-based thin-film structures. In the experiment, a modulated laser source heats up the sample and a fast-response temperature sensor patterned directly on the sample picks up the thermal response. From the phase delay between the heating source and the temperature sensor, the thermal diffusivity in either the parallel or perpendicular direction is obtained depending on the experimental configuration. The experiment is performed on a molecular-beam-epitaxy grown vertical-cavity surface-emitting laser (VCSEL) structure. The substrates of the samples are etched away to eliminate the effects of the interface between the film and the substrate. The results show that the thermal diffusivity of the VCSEL structure is 5–7 times smaller than that of its corresponding bulk media. The experiments also provide evidence on the anisotropy of thermal diffusivity caused solely by the effects of interfaces and boundaries of thin films.
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Benallegue, Mehdi, Jean-Paul Laumond i Alain Berthoz. "On the mechanical contribution of head stabilization to passive dynamics of anthropometric walkers". International Journal of Robotics Research 39, nr 4 (24.12.2019): 461–75. http://dx.doi.org/10.1177/0278364919894387.
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During the steady gait, humans stabilize their head around the vertical orientation. Although there are sensori-cognitive explanations for this phenomenon, its mechanical effect on the body dynamics remains unexplored. In this study, we take profit from the similarities that human steady gait shares with the locomotion of passive-dynamics robots. We introduce a simplified anthropometric 2D model to reproduce a broad walking dynamics. In a previous study, we showed heuristically that the presence of a stabilized head–neck system has a significant influence on the dynamics of walking. This article gives new insights that lead to understanding this mechanical effect. In particular, we introduce an original cart upper-body model that allows to better understand the mechanical interest of head stabilization when walking, and we study how this effect is sensitive to the choice of control parameters.
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Matsumoto, Yusuke, Toshikazu Wada, Shuichi Nishio, Takehiro Miyashita i Norihiro Hagita. "Scalable and robust multi-people head tracking by combining distributed multiple sensors". Intelligent Service Robotics 3, nr 1 (10.11.2009): 29–36. http://dx.doi.org/10.1007/s11370-009-0056-5.
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Rabbitt, R. D., R. Boyle i S. M. Highstein. "Sensory transduction of head velocity and acceleration in the toadfish horizontal semicircular canal". Journal of Neurophysiology 72, nr 2 (1.08.1994): 1041–48. http://dx.doi.org/10.1152/jn.1994.72.2.1041.
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1. Sinusoidal mechanical indentation of the long-and-slender limb of the horizontal semicircular canal and/or utricle was used to produce adequate stimulation of the labyrinth. Indentation of the canal increased, while indentation of the utricle decreased the afferent discharge rate. This follows because indentation of the canal and utricle produce oppositely directed mechanical stimuli as defined by endolymph flow, transcupular pressure, and cupular deflection. Simultaneous in-phase indentations of both the canal and utricle, with amplitudes adjusted to produce equal (but opposite) magnitudes of afferent response modulation, generate destructive interaction that minimizes the afferent modulation, whereas sinusoidal indentation 180 degrees out-of-phase generates constructive interaction that maximizes the afferent modulation. This observation correlates directly with analysis of the labyrinthine elasto-hydrodynamics which predicts that balanced in-phase indentations minimize macromechanical endolymph flow through the ampullary cross section and maximize the dilatational pressure within the ampulla acting equally on both sides of the cupula and across the labyrinthine wall. 2. Two groups of afferents are identified according to their response to balanced sinusoidal indentation of the canal limb and the utricle. In one group there is complete destructive interaction and the afferent response can be effectively nulled by adjusting the relative amplitude and phase of the two stimuli. In the second group a residual afferent response remains that cannot be nulled. The residual is described in the model as unit-specific sensitivity to dilatational pressure acting equally on both sides of the cupula.
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Ardeshiri, Ardeshir, Christian Radina, Martin Edlauer, Ardavan Ardeshiri, Alfred Riepertinger, Andreas Nerlich, Jörg-Christian Tonn i Peter A. Winkler. "Evaluation of new radiolucent polymer headholder pins for use in intraoperative computed tomography". Journal of Neurosurgery 111, nr 6 (grudzień 2009): 1168–74. http://dx.doi.org/10.3171/2009.1.jns08862.
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Object With the introduction of intraoperative CT (iCT) scanning, neurosurgeons can now obtain images of the brain during surgery, offering the possibility of intraoperative resection control and monitoring of potential intraoperative complications. The combination of iCT with neuronavigation makes it possible to update the reference scans intraoperatively when necessary. However, the headholder pins normally used for iCT scanning still show artifacts. In the present study, new polymer pins, producing nearly no artifacts in laboratory tests, are compared with the usual pins with regard to their mechanical and artifact behavior to evaluate their potential use in the clinical routine. Methods Pins made of different materials (titanium, Macor, silicon nitride, zirconium oxide, sapphire, polyetheretherketone, and polyparaphenylene copolymer) were used for the fixation of 10 cadaveric heads. Special force sensors measured the fixation pressure of the pins, and histological analysis revealed the penetration depth. Computed tomography scans of a head phantom, fixed with the different pins, were obtained to reveal artifact behavior. Results All pins were biocompatible. Pins did not differ significantly in fixation pressures and mechanical behavior. Penetration depths were comparable (maximum 1.4 mm) and did not cause opening of the diploe. Polymer pins made of polyparaphenylene showed the best results in artifact behavior in CT scans. Conclusions The authors' results demonstrate that the new polymer pins are comparable in their mechanical behavior to the usual pins but superior in artifact behavior. Therefore, their use in the clinical routine of iCT scanning will be beneficial for the surgeon.
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Brown, Alan S. "IoT Puts a New Spin on Bearings". Mechanical Engineering 140, nr 07 (1.07.2018): 42–47. http://dx.doi.org/10.1115/1.2018-jul-3.
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As anyone who ever had a bearing fail knows, durability counts. However some bearing makers believe that predictability is more important than longer bearing life. By harnessing the Internet of Things (IoT) and other Industry 4.0 technologies—low-cost sensors, Big Data analytics, and machine learning—manufacturing companies want to catapult one of the world’s oldest mechanical devices into the digital future. In fact, bearings are emerging as a poster child for Industry 4.0. Yet this heady mixture of digital technology and physical products is also disrupting how companies monitor, operate, and service rotating equipment; the way they sell and service products; and who they partner with and compete against. This article delves into how bearing makers are embracing this disruption.
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García-Arroyo, Jaime, Soraya Pacheco-da-Costa, Francisco Molina-Rueda, Davinia Vicente-Campos, César Calvo-Lobo i Isabel M. Alguacil-Diego. "Biosignals by In-Shoe Plantar Pressure Sensors on Different Hardness Mats during Running: A Cross-Over Study". Applied Sciences 13, nr 4 (8.02.2023): 2157. http://dx.doi.org/10.3390/app13042157.
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Although the effects of running on plantar pressures have been detailed on several surfaces with different hardness, there is a lack of studies assessing the mechanical behavior analysis by in-shoe plantar pressure sensors on different hardness mats during running. The aim of the present study was to determine in-shoe maximum forces and peak plantar pressures on mats with different hardness, such as hard, soft and air chamber mats, during running. A cross-over study was carried out including 36 amateur runners from a sport center. The maximum force and peak pressures of the foot plantar region were analyzed on three different mat hardnesses —soft and hard polyurethane foam mats and air chamber mats—by in-shoe instrumented insoles. Running on soft polyurethane foam mats presented reduced maximum forces in the whole plantar region and mainly peak pressures in the anterior part of the foot plantar region, such as the toes and first to fourth metatarsal heads, compared to hard polyurethane foam and air chamber mats. The peak pressure in the fifth metatarsal head was specifically reduced during running on soft compared to hard polyurethane foam mats, and running on these soft mats decreased calcaneus peak pressures compared to running on air chamber mats. Running on air chamber mats increased peak plantar pressures in the first metatarsal head compared to running on hard polyurethane foam mats. The mechanical behavior of mats of different hardness could be used to adjust the degree of impact on plantar pressures to determine the most appropriate materials and hardness for running.
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Katayama, Yoichi, James D. Glisson, Donald P. Becker i Ronald L. Hayes. "Concussive head injury producing suppression of sensory transmission within the lumbar spinal cord in cats". Journal of Neurosurgery 63, nr 1 (lipiec 1985): 97–105. http://dx.doi.org/10.3171/jns.1985.63.1.0097.
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✓ This study examines the effects of concussive levels of a fluid-percussion head injury on sensory transmission within the lumbar spinal cord of the cat. Primary afferent depolarization (PAD) was suppressed for 2 to 5 minutes following injury, as assessed by dorsal root potentials and augmentation of antidromic dorsal root potentials, both evoked by stimulation of adjacent dorsal roots. Polysynaptic reflex discharges in ventral root potentials evoked by dorsal root stimulation were also profoundly suppressed during this same period, even when spontaneous and monosynaptic reflex discharges were facilitated. Changes in PAD produced by injury were abolished by spinal cord transection, but were not affected by midpontine transection. These findings suggest that concussive head injury can produce suppression of segmental sensory transmission by neurally mediated processes involving the bulbar brain stem. Recordings of dorsal root resting potentials, antidromic dorsal root potentials, and reductions of antidromic dorsal root potentials induced by tetanic root stimulation indicated that depressed segmental sensory function produced by injury was due to suppression of postsynaptic interneuronal transmission rather than to excitability changes in primary afferent fibers. Somatosensory cortical potentials evoked by dorsal root stimulation were profoundly depressed at the same time as segmental sensory transmission was suppressed, suggesting that suppressed segmental sensory transmission may also contribute to suppression of ascending sensory transmission. It is hypothesized that transmission failure of interneuronal systems in the initial period following insult may be a general response occurring in wide areas of the central nervous system, and not restricted to areas to which mechanical stress is directly applied. This response pattern may result from indiscriminate activation of interconnected excitatory and inhibitory elements of interneuronal systems.
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Mitchell, M. R., R. E. Link, A. R. Dullah, Z. W. Guan i R. H. Crompton. "A Pilot Study on Thermal and Moisture Mapping of the Head-Helmet System Using Micro-Sensor Technology". Journal of Testing and Evaluation 39, nr 3 (2011): 102812. http://dx.doi.org/10.1520/jte102812.
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Haschke, Henning, Adrian Falkenberg, Michael M. Morlock i Gerd Huber. "Do SiNx coatings bear the potential to reduce the risk of micromotion in modular taper junctions?" Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 234, nr 9 (7.06.2020): 897–908. http://dx.doi.org/10.1177/0954411920930616.
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Fretting corrosion is one contributor to the clinical failure of modular joint arthroplasty. It is initiated by micromotion in metal junctions exposed to fluids. Omitting metal-on-metal contacts could help to reduce the corrosion risk. The coating of one metal taper partner with a ceramic-based silicon nitride (SiNx) coating might provide this separation. The aim of the study was to identify whether a SiNx coating of the male taper component influences the micromotion within a taper junction. Hip prosthesis heads made of CoCr29Mo6 (Aesculap) and Ti6Al4V (Peter Brehm) were assembled (2000 N) to SiNx-coated and uncoated stem tapers made of Ti6Al4V and CoCr29Mo6 (2×2×2 combinations, each n = 4). Consecutive sinusoidal loading representing three daily activities was applied. Contactless relative motion in six degrees of freedom was measured using six eddy-current sensors. Micromotion in the junction was determined by compensating for the elastic deformation derived from additional monoblock measurements. After pull-off, the taper surfaces were microscopically inspected. Micromotion magnitude reached up to 8.4 ± 0.8 µm during loading that represented stumbling. Ti6Al4V stems showed significantly higher micromotion than those made of CoCr29Mo6, while taper coating had no influence. Statistical differences in pull-off forces were found for none of the taper junctions. Microscopy revealed CoCr29Mo6 abrasion from the head taper surface if combined with coated stem tapers. Higher micromotion of Ti6Al4V tapers was probably caused by the lower Young’s modulus. Even in the contact areas, the coating was not damaged during loading. The mechanics of coated tapers was similar to uncoated prostheses. Thus, the separation of the two metal surfaces with the objective to reduce in vivo corrosion appears to be achievable if the coating is able to withstand in vivo conditions. However, the hard ceramic-based stem coating lead to undesirable debris from the CoCr29Mo6 heads during loading.
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Wilson, J., i P. Wright. "Head-mounted display efficacy study to aid first responder indoor navigation". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 223, nr 3 (1.12.2008): 675–88. http://dx.doi.org/10.1243/09544062jmes1213.
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A custom head-mounted display (HMD) integrated into a firefighter's facemask was evaluated for its ability to aid in navigating through large buildings in low-visibility conditions. The HMD was a monocular occluded design with a colour 640×480 pixel LCD mounted low in one's field of view. It showed the subject their real-time location on a floor plan. Subject location was found with an 802.15.4 wireless sensor network by using the received signal strength indicator localization method. The study consisted of two different courses of similar difficulty in different buildings in the campus of the University of California, Berkeley. There were 21 subjects, of which eight of them were firefighters and five of them were female. The subjects completed the courses in the same order, but alternated in treatment condition. Subjects with the HMD returned on average a 38 per cent faster course completion time, a 44 per cent shorter distance travelled, 60 per cent fewer navigation errors, and 60 per cent more accurate map marking. A follow-up questionnaire showed a strong preference for use of the HMD in navigation tasks, and unanimous approval of the occluded optical design and low mounting location.
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Lackner, James R., i Paul Dizio. "Altered Sensory-Motor Control of the Head as an Etiological Factor in Space-Motion Sickness". Perceptual and Motor Skills 68, nr 3 (czerwiec 1989): 784–86. http://dx.doi.org/10.2466/pms.1989.68.3.784.
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Mechanical unloading during head movements in weightlessness may be an etiological factor in space-motion sickness. We simulated altered head loading on Earth without affecting vestibular stimulation by having subjects wear a weighted helmet. Eight subjects were exposed to constant velocity rotation about a vertical axis with direction reversals every 60 sec. for eight reversals with the head loaded and eight with the head unloaded. The severity of motion sickness elicited was significantly higher when the head was loaded. This suggests that altered sensory-motor control of the head is also an etiological factor in space-motion sickness.
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Tang, Jian, Rongbiao Wang, Jikai Zhang i Yihua Kang. "The influence of magnetic head’s pose on magnetic flux leakage detection". International Journal of Applied Electromagnetics and Mechanics 64, nr 1-4 (10.12.2020): 493–500. http://dx.doi.org/10.3233/jae-209356.
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As a high-sensitivity magnetic sensor, the magnetic head has been gradually applied to non-destructive testing. Compared with the single coil and the coil with an iron core, the magnetic core can converge the weak leakage magnetic field because it can form a magnetic circuit to transmit the leakage field to the coil wound thereon. So that it has a higher sensitivity. However, in practical applications, it’s found that the pose error of the head affects its sensitivity. Therefore, this paper analyzes the influence of the tilt of the head on the magnetic core’s ability to sense leakage magnetic field, and then the influence is verified by simulations and experiments. The study finds that, when tilted around two horizontal axes, the larger the tilt angle is, the larger the signal is. When tilted around the vertical axis, the larger the tilt angle is, the smaller the signal is.
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Lazzari, Anderson, Ingrid Caroline da Silva, Gislaine Gonçalves Oliveira, Bianca de Oliveira Muller, Elisângela de Cesaro, Bianka Rocha Saraiva, Ana Carolina Pelaes Vital, Maria Luiza Rodrigues de Souza i Paula Toshimi Matumoto-Pintro. "Physic-chemical characteristics and sensory evaluation of cakes with Nile tilapia (Oreochromis niloticus) waste flour". Research, Society and Development 10, nr 7 (29.06.2021): e47210716725. http://dx.doi.org/10.33448/rsd-v10i7.16725.
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The fish processing industry generates a large amount of waste, that can be a nutrients source to the foods enrichment, such as cake that has low proteins, and consumed for different social classes. This study aimed to produced cakes with Nile tilapia (Orechromis niloticus) waste flour (NWF), formed by head, fins and the spine with meat remaining from filleting process, and evaluate its chemical and sensory properties. The formulations cakes with NWF obtained products with higher protein contents, essential fatty acids, and minerals, especially calcium and phosphorus, and lower car-bohydrates contents in relation to Control formulation (without NWF). The cakes with NWF had sensory acceptance (scores higher than 7.0 from 9.0 points) and purchase intention (scores higher than 3.8 from 5.0 points) and did not differ from the Control. The cakes with NWF can be a way to increase the supply of essential nutrients to the population through a popular and sensorial accepted product. This study showed that Nile tilapia waste flour (NWF) heads stands out a promising source for producing cake with high nutritional quality, positive economic potential, better physicochemical properties and, food industry solid waste reduction by used in food.
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S., Manikandan, i Dr B. Suresh Kumar. "ENERGY EFFICIENT CLUSTERING ALGORITHM FOR MOBILE CLUSTER HEADS TO ENHANCE THE LIFESPAN OF WIRELESS SENSOR NETWORK". Indian Journal of Computer Science and Engineering 12, nr 3 (25.06.2021): 605–17. http://dx.doi.org/10.21817/indjcse/2021/v12i3/211203085.
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Ding, Kai, i Pingyu Jiang. "Incorporating social sensors, cyber-physical system nodes, and smart products for personalized production in a social manufacturing environment". Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 232, nr 13 (25.06.2017): 2323–38. http://dx.doi.org/10.1177/0954405417716728.
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As manufacturing industry heads toward the socialization and mass individualization, customer requirements have become personalized and dynamic. Socialized manufacturing resources spring up in different finer-grained market segments to provide various manufacturing services for customers. To facilitate the mass business collaboration, these resources and customers need to be cyber-physical-social interconnected. This article proposes a cyber-physical-social system for the personalized product production in a social manufacturing environment, which incorporates social sensors in the human end, cyber-physical system nodes in the machine end, and smart products in the product end for social interaction and distributed production control. The three-layer framework of cyber-physical-social system and three-stage interaction scenarios are discussed. The multi-role distributed production control mechanism is studied to enhance the agility, responsiveness, flexibility, and coordination capability of the cyber-physical-social system–enabled personalized product production system. Cyber-physical-social system leverages the global cyber-physical-social convergence and the local regional autonomy for the personalized product production. It is expected that this article will contribute to the research areas of industry 4.0-based manufacturing mode innovation and intelligent production process control.
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Wu, Lan Ying, Yan Lin Wang i Jing Deng. "Study on the Microstructure and Properties of Suspensory Wire in DVD CD-ROM Head". Advanced Materials Research 142 (październik 2010): 95–98. http://dx.doi.org/10.4028/www.scientific.net/amr.142.95.
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The suspensory wire is widely applied in the fields of DVD CD-ROM head and various sensors. In this paper, the suspensory wires are analyzed with the SEM, X-ray energy spectrum and Hydrogen power spectrum et al. The research results show that the alloy composition of the suspensory wire is the composite materials, which is composed of silver, beryllium and copper bimetal; The Nano-indentation hardness tester is also did using the hanging Nano-indentation experiments on the suspensory wire, it’s to obtain more accurate mechanical properties parameters of material hardness and so on, then we get the average hardness of suspensory wire is 3.891 GPa; The average elasticity modulus decreases as the aging treatment time increases, and the average tensile strength increases as the aging treatment time increases.
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Bi, Guijun, Bert Schürmann, Andres Gasser, Konrad Wissenbach i Reinhart Poprawe. "Development and qualification of a novel laser-cladding head with integrated sensors". International Journal of Machine Tools and Manufacture 47, nr 3-4 (marzec 2007): 555–61. http://dx.doi.org/10.1016/j.ijmachtools.2006.05.010.
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Tiller, Sandra G., i M. A. Persinger. "Test-Retest Scores for Patients Who Display Neuropsychological Impairment following “Mild Head Injuries” from Mechanical Impacts". Perceptual and Motor Skills 86, nr 3_suppl (czerwiec 1998): 1240–42. http://dx.doi.org/10.2466/pms.1998.86.3c.1240.
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A total of 20 patients who had sustained impact of significant mechanical energies to the skull (>40 km/hour) were assessed at Time 1, about one year (68% between 2 mo. and 12 mo.) postincident while Time 2 was about two years later. During Time 1 this group was impaired (proficiency z<−2.00) according to two standardized neuropsychological indices and exhibited abnormally elevated psychometric depression ( z>2.00). There were no statistically significant improvements for the scores between Times 1 and 2 on the Halstead-Reitan Impairment Index, the Memory Quotient, Depression, or an impairment index composed of standardized scores for 31 neuropsychological tests. These results indicated that the presumption of some neuropsychologists that patients with “mild head injury” have fully recovered within one year or will continue to improve after about one year following the incident may not be valid for all patients who sustain such brain trauma.
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Moore, Steven T., Eishi Hirasaki, Theodore Raphan i Bernard Cohen. "Instantaneous rotation axes during active head movements". Journal of Vestibular Research 15, nr 2 (1.04.2005): 73–80. http://dx.doi.org/10.3233/ves-2005-15203.
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Rotation axes were calculated during active head movements using a motion analysis system. The mean rotation axis for 1 Hz head pitch when seated was posterior (6 mm) and inferior (21 mm) to the interaural axis, shifting 16 mm downwards when standing. During seated 2 Hz head pitch the rotation axis was close to the interaural axis, shifting downwards 15 mm when standing. This downward shift suggests that cervical vertebrae were recruited during head pitch with the trunk unsupported. The proximity of the pitch axis to the otoliths implies minimal otolith activation during small-amplitude, high-frequency pitch rotations, such as those encountered during locomotion. The mean rotation axis for 1 Hz yaw rotation was located slightly posterior (10 mm) to the interaural axis at the midpoint between the vestibular labyrinths when both seated and standing. In addition, the orientation of the plane of yaw rotation relative to the stereotaxic horizontal plane (pitched 5° nose-down) was essentially fixed in head coordinates, regardless of the pitch orientation of the head, suggesting that yaw movements occur about an axis restricted by the mechanical structure of the atlanto-axial joint. The results demonstrate that the instantaneous rotation axes technique overcomes the inherent instability of the helical-axis representation for small head movements.
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Paquet, Nicole, Douglas G. D. Watt i Luc Lefebvre. "Rhythmical eye-head-torso rotation alters fore-aft head stabilization during treadmill locomotion in humans*". Journal of Vestibular Research 10, nr 1 (1.02.2000): 41–49. http://dx.doi.org/10.3233/ves-2000-10105.
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A repetitive manoeuvre called torso rotation (TR) is known to temporarily reduce the gain of the horizontal vestibulo-ocular reflex by 10–15% consists of a series of rhythmical rotations of the eyes, head and upper body executed continuously for 30 minutes while standing. Our aim was to investigate whether TR affects the ability to hold the head in a fixed fore-aft position relative to space while walking on a treadmill with eyes closed. Ten healthy subjects stood in a carefully standardized position on a stationary treadmill. The treadmill started unexpectedly and ran for 4 s at 29 cm/s. The test stimulus was a linear acceleration in the fore-aft direction at the moment of treadmill start-up. Linear head position (i.e., ability to stabilize the head) was measured during and following the stimulus. A mechanical system prevented head rotation. Two series of 60 trials were performed before TR (control 1 and control 2 series) and one after TR. Before TR, subjects drifted rearward at an average drift velocity ± S.D. = 3.1 ± 0.9 cm / s. This drift was reasonably stable over time within and between the two control series. After TR, head holding ability was further impaired, with subjects having more difficulty to stabilize their head after treadmill start-up. In the first 10 trials after the arrest of TR, the average drift velocity was significantly larger than before TR ( 6.1 ± 1.5 cm / sec, p < 0.01). Recovery to control values followed a roughly exponential time course, with 67% impairs the ability to sense and/or respond to fore-aft linear accelerations of the head following treadmill start-up in the absence of vision.
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Jones, Timothy A., Choongheon Lee, G. Christopher Gaines i J. W. “Wally” Grant. "On the High Frequency Transfer of Mechanical Stimuli from the Surface of the Head to the Macular Neuroepithelium of the Mouse". Journal of the Association for Research in Otolaryngology 16, nr 2 (4.02.2015): 189–204. http://dx.doi.org/10.1007/s10162-014-0501-9.
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