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Journal articles on the topic 'Rubber Noise Measurement'
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1
Rizkya, I., K. Syahputri, R. M. Sari, and I. Siregar. "Measurement of Noise Level in Enumeration Station in Rubber Industry." IOP Conference Series: Materials Science and Engineering 180 (March 2017): 012121. http://dx.doi.org/10.1088/1757-899x/180/1/012121.
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Guo, Zhao Yang, and Guo Hui Shen. "Analysis of Tire-Pavement Noise Spectrum of Noise Reduction Dense Asphalt-Rubber Pavement." Advanced Engineering Forum 5 (July 2012): 345–51. http://dx.doi.org/10.4028/www.scientific.net/aef.5.345.
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The types of noise reduction asphalt pavement were summarized such as single layer porous or two-layer porous asphalt pavement, elastic asphalt pavement, optimized surface texture pavement, and universally composable one based on these three types. In Beijing China, it was very drought and short of rainfall, there were large volume of traffic, heavy wheel load and many dirt things on the pavement surface taken by the tires too. So asphalt-rubber pavement was the most common one for noise reduction, which was paved by gap-graded, macrotexture, dense asphalt concrete, belonging to the types of elastic and optimized surface texture noise reduction pavement. And it could reduce tire-pavement noise obviously and had excellent durability, All proved that this types of noise reduction pavement had gone through traffic and climate environment of Beijing well. It had measured tire-pavement noise of asphalt–rubber pavement and stone mustic asphalt pavement in Beijing from 2009 to 2012. This measurement was according to Measurement of close-proximity method，which prepared by international organization for standardization in the year 2000. And the test vehicle was a trailer for measuring tire-pavement noise which met requirements of ISO/CD 11819-2:2000. The factors effected tire-pavement noise spectrum were analysed, such as temperature, speed, age of pavement and so on. It reveals that, The tire-pavement noise sound level could get higher especially higher during the frequency 500Hz~2500Hz in the noise spectrum, while the testing speed increase, or the temperature decrease , or the age of pavement grow. while the frequency lay on the range of higher than 800 Hz, the asphalt–rubber pavement’s noise sound level were lower than the stone mustic asphalt pavement’s one in all situations, and when the temperature decreased from 30°C to 0°C , the low limit frequency decreased from 800Hz to 63 Hz . In order to show the reason , it had tested dynamic modulus and phase angle of the two kinds of pavement materials under different temperature and load frequency with the help of Simple Performance Tester, The result shows that, asphalt-rubber concrete has smaller Phase angle at wide temperature as well as frequency changes, it could be one of the main reasons to explain this phenomenon. It could provide reference for designing, constructing, maintaining and evaluating the noise reduction asphalt pavement.
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Singh, Chitransh, and Madan Lal Chandravanshi. "Performance and noise analysis of vibratory feeder using dynamic rubber spring model." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 2 (October 25, 2019): 530–43. http://dx.doi.org/10.1177/0954406219884967.
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In vibratory feeder, material feeding occurs due to the vibration of a trough mounted on helical springs. High vibration amplitude of trough causes the springs to jump and usually results in higher noise level generation and increase in force transmissibility in the support structure of the feeder. Reducing this noise without having significant changes in the dynamics of the feeder unit is a major challenge in the present industries. This paper presents a dynamic rubber spring model for vibratory feeders to reduce the noise level and the force transferred to the support structure of the feeder. Measurement of dynamic parameters such as vibration amplitude and magnitude of force transmitted to support structure, noise level, and conveying speed of particle analyses have been conducted experimentally on vibratory feeder with and without rubber gasket installed at spring support structure. The use of rubber gaskets at spring supports and their implication on force transmissibility and noise level of feeder is established experimentally. The performance analysis of feeder was also conducted using particle conveying speed on trough for different setups of feeder unit. It was found that the introduction of rubber gaskets at spring supports of the feeder increases the system damping, which helps in noise reduction as well as reduced amplitude of vibration and higher acceleration of trough. The increased acceleration leads to higher particle conveying velocity on the feeder trough.
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Leupolz, Michael, and Frank Gauterin. "Vehicle Impact on Tire Road Noise and Validation of an Algorithm to Virtually Change Tires." Applied Sciences 12, no. 17 (September 1, 2022): 8810. http://dx.doi.org/10.3390/app12178810.
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Especially for electric vehicles, the tire impact on car noise is becoming more and more important. The requirement of meeting certification criteria makes estimating the sound pressure level essential for vehicle manufacturers. Most recent research on tire road noise is conducted on component test benches. Little research exists into tires mounted on vehicles, and even less into the impact of acceleration on the generated noise. The literature mainly considers some vehicle shape differences, tire load, and inflation pressure. This article investigates the impact of different vehicles on tire noise through a series of measurements on a standardized test track. The rolling noise as well as accelerated noise of three different tires and five different vehicles are compared. The impact of the drive axle on accelerated noise as well as a weight variation is investigated. Additionally to the absolute measured differences between the vehicles, statistical methods are used to separate measurement dispersion from actual systematic differences. This research therefore validates older research on the vehicles’ impact on tire noise, which is necessary since the general tire structure, thread, and rubber composition have changed in the time period between the publication of previous research from the literature and this paper. This allows us to approximate the emitted noise on different vehicles. Furthermore, we validate an algorithm to virtually change tires on test benches. The algorithm is standardized and implemented in common measurement software.
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Matsuo, Kazuya, Toshiharu Mukai, and Shijie Guo. "Unconstrained Measurement of Heart Rate Considering Harmonics of Respiratory Signal Using Flexible Tactile Sensor Sheet." Journal of Robotics and Mechatronics 33, no. 4 (August 20, 2021): 826–32. http://dx.doi.org/10.20965/jrm.2021.p0826.
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Measurement of the sleeping state is useful for monitoring the health of a person being nursed. The sleeping state can be estimated from biological information such as respiration rate, heart rate, body motion, and lying posture. A heart rate measurement method that considers the harmonics of a respiratory signal is described herein. The harmonics of respiratory signals for heart rate measurement has not been considered hitherto. An unconstrained method is proposed for measuring respiration, heart rate, and lying posture using a Smart Rubber sensor, which is a rubber-based flexible planar tactile sensor developed for this study. Respiration and heart rates are measured by applying frequency analysis to time-series data of body pressure. The harmonics of a respiratory signal serves as noise in heart rate measurement. Therefore, the heart rate measurement is improved by eliminating the effects of harmonics. The average frequency error of the heart rate measurement by our proposed method is 0.144 Hz. Experimental results show that our proposed method enhances the precision of heart rate measurement. Hence, this method enables the accurate measurement of the sleeping state.
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Li, Caoyang, David Herrin, John Baker, and Asad M. Sardar. "Simulation of rubber grommets and correlation with test at low frequencies." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 1 (August 1, 2021): 5740–47. http://dx.doi.org/10.3397/in-2021-3246.
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Residential air conditioning units include several sources which can lead to vibrational and noise issues. The most important structure-borne source is the compressor which controls the noise and vibration in certain frequency ranges. Compressors are mounted on four relatively stiff rubber grommets which partially isolate the basepan from the compressor motion while also ensuring that the compressor does not move too much. In this work, the grommets are simulated using the finite element method and results are correlated with measurement results with good agreement. It is demonstrated that the hyperelastic properties of the grommets should be increased due to the Payne effect to improve correlation.
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Baheti, Vijay, and V. Kothari. "Novel method of sound barrier measurement of porous and nonporous materials." World Journal of Engineering 10, no. 4 (August 21, 2013): 353–58. http://dx.doi.org/10.1260/1708-5284.10.4.353.
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Noise is an unwanted sound which creates the pollution and adverse effects on individual. One of the simple ways to reduce the noise is to place the acoustic material in the path between the source and the receiver so that sound waves get either absorbed or blocked while reaching towards the receiver. There are various techniques available to measure sound absorption or sound barrier (blocking) caused by the acoustic material. However these techniques are also associated with certain limitations. Our objective was to design and fabricate simple technique to measure sound barrier which overcomes these limitations and allows larger sample size and random scatter of sound wave to accurately predict actual field measurements. A sound source (i.e. a speaker) and a microphone, placed in different pipes separated by sample in between, were used for the measurement of sound barrier property of porous materials (nonwovens, woven fabric, and foam), nonporous materials (rubber, cardboard) and their composite structures at four different frequencies 250 Hz, 500 Hz, 1,000 Hz, and 2000 Hz. Different set of readings were taken in absence and presence of the sample by measuring the transmitted sound across the sample.
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Juliyati, Riri, Zulfan Saam, and Nopriadi Nopriadi. "Hubungan Shift Kerja dan Kebisingan dengan Stres Kerja Pada Karyawan Bagian Produksi Gilingan PT. Riau Crumb Rubber Factory Pekanbaru." Dinamika Lingkungan Indonesia 1, no. 2 (July 14, 2014): 88. http://dx.doi.org/10.31258/dli.1.2.p.88-96.
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This research aims to analyze the correlation between shift work and noise withwork stress of the workers in milling production division of PT . Riau Crumb Rubber Factory.This research is an observational analytic with cross sectional approach. The population ofthis study consists of 125 workers in milling production. With purposive sampling techniqueand using predetermined criteria obtained a total sample of 60 people. The data werecollected using work stress scale and the measurement noise by using a sound level meter andanalyzed with bivariate using the chi square test. The results showed that there was asignificant correlation between work shifts with work stress with p value (0.000) < α ( 0.05 ).Employees who work on the night shift tend to have a high work stress when compared withemployees working on the morning shift and afternoon . There is a significant correlationbetween the level of noise with work stress with p value (0.000) < α ( 0.05 ). The higher thenoise level the higher work stress.
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Yang, Chao-Feng, Zhi-Hong Yin, Wen-Bin Shangguan, and Xiao-Cheng Duan. "A Study on the Dynamic Performance for Hydraulically Damped Rubber Bushings with Multiple Inertia Tracks and Orifices: Parameter Identification and Modeling." Shock and Vibration 2016 (2016): 1–16. http://dx.doi.org/10.1155/2016/3695950.
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Hydraulically damped rubber bushings (HDBs) are important for vehicle noise, vibration, and harshness (NVH) performance as they are able to decay the vehicle’s oscillation induced by engine and road. The dynamic stiffness and loss angle of an HDB are crucial and it is significant to investigate the relations between the design parameters with the dynamic stiffness and loss angle. Therefore, the force-deflection relation of the HDB is measured statically and the dynamic stiffness and loss angle are measured dynamically and the test data are analyzed with a view to examine how the measurement results are influenced by the design parameters (the number of the fluid tracks). Compared with the results predicted by a nonlinear lumped parameter model whose parameters are extracted by a parameter identification technique, using the model, the effect of the main rubber and the fluid track on the dynamic stiffness and the loss angle is investigated. A unified analytical model of HDB is also developed with the purpose of predicting the static and dynamic characteristics, and the predictions are shown to be well correlated with the measurement data. The good correlation suggests the validity of the model and the parameter identification implementation.
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Czech, Krzysztof Robert, and Wladyslaw Gardziejczyk. "Dynamic Stiffness of Bituminous Mixtures for the Wearing Course of the Road Pavement—A Proposed Method of Measurement." Materials 13, no. 8 (April 23, 2020): 1973. http://dx.doi.org/10.3390/ma13081973.
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Stiffness is an important mechanical characteristic of asphalt mixtures used in the wearing course. It is one of the determining factors in the generation of tyre/road noise. The dynamic stiffness of the upper layer of the road surface depends on the physical and mechanical properties of the materials it is composed of, and traffic load. Determination of dynamic stiffness, both in laboratory conditions and in situ, requires consideration of many other factors. Tests of dynamic properties of road surfaces in field conditions are most often conducted with the help of modal hammers. Impulse excitation results are usually less accurate than those in the application of modal exciters. The test stand was constructed, comprising a tripod, 32-channel and 24-bit data acquisition system, exciter, signal amplifier, impedance head, single-axis piezoelectric accelerometers and a stinger. The test stand and the proposed method of measuring dynamic stiffness do not require the determination of the resonance frequency of the tested specimen and can be used both on various types of bituminous mixtures of varying shape and dimensions, as well as directly on the upper surface of the wearing course of bituminous pavements. The test results showed that the type of bituminous mixture used in the wearing course significantly affects its dynamic stiffness. The dynamic stiffness level of asphalt concrete, stone mastic asphalt and porous asphalt layers was determined to be similar. The addition of rubber granulates significantly reduced its rigidity, which is very beneficial from the point of view of reducing the tyre/road noise.
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Guo, Chenjun, Lishuai Liu, Hongwei Mei, Yanxin Tu, and Liming Wang. "Nondestructive Evaluation of Composite Bonding Structure Used in Electrical Insulation Based on Active Infrared Thermography." Polymers 14, no. 16 (August 18, 2022): 3373. http://dx.doi.org/10.3390/polym14163373.
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Nondestructive testing and evaluation of composite insulating components of electrical equipment is extremely necessary for assuring the safety of a power system. However, most existing nondestructive testing methods are not applicable for fast and effective live detection due to their time-consuming operation, high cost, and contact or near-field measurement. In this work, the effectiveness of active infrared thermography was investigated for detecting defects in silicone rubber (SIR)–fiber-reinforced plastic (FRP) bonding structures, which have been commonly used in insulating components of power equipment. The effectiveness of differential thermal image for enhancing the contrast of defective and sound areas and eliminating additive noise was demonstrated. Particularly, frame difference thermal image obtained by subtracting two differential thermal images extracting from respectively before and after the contrast inversion was proposed to enhance defect identification. The results revealed that defects of various sizes and depths such as voids, cracks, and interface disbonding of the SIR–FRP bonding structure were accurately detected by thermographic data. With the advantages of a quick and simple process, safety, universal applicability, visual results, far-field measurement, and quantitative defect estimation capabilities, active infrared thermography would be quite promising for live detection of electrical equipment.
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Castellini, P. "Vibration Measurements by Tracking Laser Doppler Vibrometer on Automotive Components." Shock and Vibration 9, no. 1-2 (2002): 67–89. http://dx.doi.org/10.1155/2002/260478.
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This paper describes the application of a Tracking Laser Doppler Vibrometer (TLDV) to the measurement of vibration of some typical automotive component.After a presentation and discussion of the measurement technique, the attention is focused on the development of specific version optimised for each application.The first component analysed is the sidewall of a tire during its rotation in a typical drum test-bench. An optimised version of the TLDV was developed for the specific application adding a trajectory assessment tool based on image analysis, in order to fulfil the accuracy specifications imposed by tire manufacturer.The second automotive component is a timing belt.This application presents problems related to the high-speed linear motion and to data processing for noise rejection. The third application is on windscreen wipers. In this case the tracking approach fully demonstrate his capabilities, representing the only technique able to give information in the time domain on the dynamic behaviour of the rubber blade in operative conditions.All the application shows as the TLDV allows to obtain realistic results on the dynamic characteristics under simulated operative conditions.A Lagrangian approach was adopted: data were acquired with the target in continuously changing conditions and that impose a not traditional approach on LDV data such as a joint time-frequency analysis.
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Liptai, Pavol, Marek Moravec, and Miroslav Badida. "Research of Possibilities of Using the Recycled Materials Based on Rubber and Textiles Combined with Vermiculite Material in the Area of Noise Reduction." Advanced Materials Research 1001 (August 2014): 171–76. http://dx.doi.org/10.4028/www.scientific.net/amr.1001.171.
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This paper describes possibilities in the use of recycled rubber granules and textile materials combined with vermiculite panel. The aim of the research is the application of materials that will be absorbing or reflecting sound energy. This objective is based on fundamental physical principles of materials research and acoustics. Method of measurement of sound absorption coefficient is based on the principle of standing wave in the impedance tube. With a sound level meter is measured maximum and minimum sound pressure level of standing wave. From the maximum and minimum sound pressure level of standing wave is calculated sound absorption coefficient αn, which can take values from 0 to 1. Determination of the sound absorption coefficient has been set in 1/3 octave band and in the frequency range from 50 Hz to 2000 Hz. In conclusion are proposed possibilities of application of these materials in terms of their mechanical and physical parameters.
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Dimitrijević, Stefan M., Víctor M. García-Chocano, Francisco Cervera, Emelie Roth, and José Sánchez-Dehesa. "Sound Insulation and Reflection Properties of Sonic Crystal Barrier Based on Micro-Perforated Cylinders." Materials 12, no. 17 (August 31, 2019): 2806. http://dx.doi.org/10.3390/ma12172806.
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A sonic crystal barrier, consisting of empty micro-perforated cylindrical shells, was built on the campus at the Universitat Politècnica de València in 2011 and characterised by using a non-standardised measurement technique. In this paper, the sonic crystal barrier, upgraded with rubber crumb inside the micro-perforated cylindrical shells, was characterised by using standardised measurement techniques according to EN 1793-5 and EN 1793-6. As a result of the characterisation, sound insulation properties of the barrier were shown to be a combination of the absorptive properties of the individual building units and the reflective properties of their periodic distribution. In addition, its performance was compared with a similar barrier consisting of rigid polyvinyl chloride (PVC) cylinders, which was recently characterised using the same standardised techniques. In comparison with the barrier based on PVC cylinders, the barrier investigated here produced a broadband enhancement of the sound insulation and lower reflection indices in the targeted frequency range. It was also shown that the influence of leakage under the barrier and the width of the temporal window on sound insulation was negligible. While EN 1793-5 and 1793-6 allow a direct comparison of the performance of different noise barriers, the applicability to this new type of barriers requires further investigation.
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Sa'adon, Shafizah, and Anika Zafiah Mohd Rus. "Acoustical Behavior of Treated Wood Dust-Filler for Polymer Foam Composite." Applied Mechanics and Materials 465-466 (December 2013): 1039–43. http://dx.doi.org/10.4028/www.scientific.net/amm.465-466.1039.
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Wood dust filler-polymer foam composite has been studied and proved to have ability to absorb sound. In this study, treated rubber and Meranti wood dust named as RA and MA respectively was use as the filler. This study was developed to compare the behavior of sound absorption based on treated filler and particle size of wood dust. By choosing the size of 355 and 710 μm, three different percentages has been selected which is 10%, 15% and 20% for both type of wood dust. These samples has been tested by using Impedance Tube test for sound absorption coefficient (α) measurement and Noise Reduction Coefficient measurement (NRC) and Scanning Electron Microscopy (SEM) to determine the diameter of pore for selected size and type of wood dust-polymer foam composite. The pore size and structure was influence the sound absorption behavior of each sample. 355 μm-polymer foam composite of every percentage loading shows the uniform pore structure as compared to 710 μm of particle size. NRC results shows that increasing pore size has decrease the NRC value. It is therefore, concluded that the sound absorption coefficient for eachsound absorbing material, with different sizes of wood dust particles, types of wood dust and the percentages of wood dust loading in polymer foam matrix effect the sound absorption behavior.
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Hudeček, Leopold, Jiří Svoboda, and Jan Kramný. "Reducing the Negative Effects of City Railways on Houses in Ostrava." Advanced Materials Research 1041 (October 2014): 432–35. http://dx.doi.org/10.4028/www.scientific.net/amr.1041.432.
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The paper discusses measures to reduce the negative effects of tram traffic on residential house in Ostrava, where the tram line passes through the street area located under the structure of the house see Figure 1.Fig.1HouseNo.1340inOstravaaffectedbyvibrationsfromrailtransportThe lines of urban railways are often kept at densely built-up areas, often in close proximity to the buildings. It is necessary to put a high emphasis on protection against noise and vibration. In case of structures for residential buildings it has a negative effect on residents. An efficient way to reduce the vibration levels of the protected structure and thus the secondary noise is elastic foundation structure as a whole to its support structure. But in practice, we need to solve the problem of the ex post, i.e. when the structure of a residential building already exists.To reduce the transmission of vibrations to the structure was carried out technical measures for vibration attenuation along the route of the spread it is the path from the source to the protected structure. Railway track was imposed on rubber anti-vibration mats under gravel bed of tram line. Furthermore, the test sections were established in order to test the application of different materials used as a grout space between the rails and the surrounding environment and the reference section to compare the resulting data.Subsequently was held the measurement of noise and vibration. Vibrations were measured on the own construction of the house, also on the communication - vertical vibration near the track (30 cm far from the running rail track), these data present the transmission of vibration from the rail and sleepers in the immediate surroundings, measuring the vertical vibrations of the road (150 cm far from the running rail track in place that was not affected by reconstruction), these data present the transmission of vibration to the subsoil neighborhood.
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Hiramitsu, Atsuo, Susumu Hirakawa, Takahiro Tsuchimoto, and Takashi Yamauchi. "Effect of different types of ceilings on floor impact sound insulation performance in CLT model building." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 2 (August 1, 2021): 4402–9. http://dx.doi.org/10.3397/in-2021-2693.
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The floor impact noise generated in a building often causes problems among residents. The floor impact sound insulation performance of timber construction buildings is lower than that of concrete construction. However, due to the large supply of wood and the stress-relieving effects of wood, the use of wood is being promoted around the world. In Japan, the Act on the Promotion of the Utilization of Wood in Public Buildings was enforced to promote the use of CLT (Cross Laminated Timber) for the effective use of wood. We have been experimentally investigating the effect of floor finish structure in CLT model building. In this paper, we report the measurement results of the change in floor impact sound insulation performance when the suspended ceiling structure was changed. As results, it was confirmed that the effect of the sound-absorbing material in the ceiling cavity and the effect of the double-layer ceiling board were effective. In addition, it was clarified that the dry-type double floor structure with rubber vibration insulator on its legs is an effective floor finish structure for improvement of heavy and light weight floor impact sound insulation performances.
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Ghalem, Kamel Ghanem, and Fatiha Hendel. "Dual iris authentication system using dezert smarandache theory." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 6 (December 1, 2019): 4703. http://dx.doi.org/10.11591/ijece.v9i6.pp4703-4712.
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In this paper, a dual iris authentication using Dezert Smarandache theory is presented. The proposed method consists of three main steps: In the first one, the iris images are segmented in order to extract only half iris disc that contains relevant information and is less affected by noise. For that, a Hough transform is used. The segmented images are normalized by Daugman rubber sheet model. In the second step, the normalized images are analyzed by a bench of two 1D Log-Gabor filters to extract the texture characteristics. The encoding is realized with a phase of quantization developed by J. Daugman to generate the binary iris template. For the authentication and the similarity measurement between both binary irises templates, the hamming distances are used with a previously calculated threshold. The score fusion is applied using DSmC combination rule. The proposed method has been tested on a subset of iris database CASIA-IrisV3-Interval. The obtained results give a satisfactory performance with accuracy of 99.96%, FAR of 0%, FRR of 3.89%, EER of 2% and processing time for one iris image of 12.36 s.<em> </em>
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Zhang, Hao, Xianqi Li, Yunmei Chen, Jewook Park, An-Ping Li, and X. G. Zhang. "Postprocessing Algorithm for Driving Conventional Scanning Tunneling Microscope at Fast Scan Rates." Scanning 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/1097142.
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We present an image postprocessing framework for Scanning Tunneling Microscope (STM) to reduce the strong spurious oscillations and scan line noise at fast scan rates and preserve the features, allowing an order of magnitude increase in the scan rate without upgrading the hardware. The proposed method consists of two steps for large scale images and four steps for atomic scale images. For large scale images, we first apply for each line an image registration method to align the forward and backward scans of the same line. In the second step we apply a “rubber band” model which is solved by a novel Constrained Adaptive and Iterative Filtering Algorithm (CIAFA). The numerical results on measurement from copper(111) surface indicate the processed images are comparable in accuracy to data obtained with a slow scan rate, but are free of the scan drift error commonly seen in slow scan data. For atomic scale images, an additional first step to remove line-by-line strong background fluctuations and a fourth step of replacing the postprocessed image by its ranking map as the final atomic resolution image are required. The resulting image restores the lattice image that is nearly undetectable in the original fast scan data.
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Jovalekic, Nikola, Vujo Drndarevic, Ermanno Pietrosemoli, and Iain Zennaro. "Experimental Study of LoRa Transmission over Seawater." Sensors 18, no. 9 (August 29, 2018): 2853. http://dx.doi.org/10.3390/s18092853.
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Low Power Wide Area Networks (LPWANs) are gaining attention in both academia and industry by offering the possibility of connecting a large number of nodes over extended distances. LoRa is one of the technologies used as a physical layer in such networks. This paper investigates the LoRa links over seawater in two typical scenarios: clear Line-of-Sight (LOS) and obstructed path in two different Industrial, Scientific and Medical (ISM) radio bands: 868 MHz and 434 MHz. We used three different LoRa devices in the experiments: the Own Developed LoRa Transceiver (ODT) and two commercial transceivers. Firstly we investigated transceivers’ Receive Signal Strength Indicator (RSSI) and Signal-to-Noise (SNR) measurement chain linearity and provided correction factors for RSSI to correlate it with actual signal levels received at transceivers’ inputs. Next, we carried out field experiments for three different LoRa Spreading Factors, S F ∈ [ 7 , 10 , 12 ] , within a bandwidth of B W = 125 kHz and Coding Rate C R = 4 / 6 . The experiments showed that LoRa links are fully feasible over seawater at distances at least 22 km long, using only low-cost off-the-shelf rubber duck antennas in LOS path condition in both ISM bands. In addition, we showed that LoRa links can be established over 28 km obstructed LOS oversea path in ISM 434 MHz band, but using costly, higher gain antennas. Furthermore, the laboratory experiments revealed that RSSI is linear in a wide range, up to - 50 dBm, whereas the SNR measurement chain goes into saturation for Received Signal Strength (RSS) values higher than - 100 dBm. These findings enabled accurate interpretation of the results obtained in field experiments.
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Fu, Renqi, Wenmiao Shen, Jue Hou, and Wanxiang Lou. "Principle and Experimental Study of Flow Noise Reduction for Underwater Vehicle Hull-Mounted Sonar." Journal of Physics: Conference Series 2419, no. 1 (January 1, 2023): 012061. http://dx.doi.org/10.1088/1742-6596/2419/1/012061.
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Abstract When the underwater vehicle is sailing at high speed, the noise of flow becomes one of the principal background noises of the hull-mounted sonar, and suppressing the flow noise is an important way to further develop the detection execution of the hull-mounted sonar. In this paper, by establishing a physical model for the analysis of flow noise, The theoretical calculation of the fluctuating level of noise acquired by a plane element sensor imbedded in an rubbery layer is performed, and the impact of different wave-number filter elements such as sensor receiving area and rubbery layer on reducing turbulent noise is discussed, and then, the effectiveness of the flow noise reduction is verified through the measurement in a large-scale flow noise test tunnel.
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Shen, Zhanpeng, Xinen Liu, Chaoping Zang, and Shaoquan Hu. "Bayesian Uncertainty Identification of Model Parameters for the Jointed Structures with Nonlinearity." Shock and Vibration 2021 (November 22, 2021): 1–17. http://dx.doi.org/10.1155/2021/2638995.
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Jointed structures in engineering naturally perform with some of nonlinearity and uncertainty, which significantly affect the dynamic characteristics of the structural system. In this paper, the method of Bayesian uncertainty identification of model parameters for the jointed structures with local nonlinearity is proposed. Firstly, the nonlinear stiffness and damping of the joints under the random excitation are represented with functions of excitation magnitude in terms of the equivalent linearization. The process of uncertainty identification is separated from the representation of local nonlinearity. In this way, the dynamic behavior of the joints is penetratingly characterized instead of ascribing the nonlinearity to uncertainty. Secondly, a variable-expanded Bayesian (VEB) method is originally proposed to identify the mixed of aleatory and epistemic uncertainties of model parameters. Different from traditional Bayesian identification, the aleatory uncertainties of model parameters are identified as one of the most important parts rather than only measurement noise of output. Notablely, a series of intermediate variables are introduced to expand the parameter with aleatory uncertainty in order to overcome the difficulty of establishing the likelihood function. Moreover, a 3-DOF numerical example is illustrated with case studies to verify the proposed method. The influence of observed sample size and prior distribution selection on the identification results is tested. Furthermore, an engineering example of the jointed structure with rubber isolators is performed to show the practicability of the proposed method. It is indicated that the computational model updated with the accurately identified parameters with both nonlinearity and uncertainty has shown the excellent predictive capability.
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Scheele, F., C. B. Lambalk, J. Schoemaker, H. van Kessel, J. de Koning, J. A. M. J. van Dieten, G. P. van Rees, and T. J. M. de Vries Robles-Korsen. "Patterns of LH and FSH in men during high-frequency blood sampling." Journal of Endocrinology 114, no. 1 (July 1987): 153–60. http://dx.doi.org/10.1677/joe.0.1140153.
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ABSTRACT The aim of the study was to test the hypothesis that in serial determinations of concentrations of LH and FSH involving blood samples taken every minute, the observed pulses of LH and FSH which last less than 3–4 min might not be a physiological phenomenon but part of the 'noise' of the radioimmunoassay or blood-sampling technique. Blood was sampled every minute for a period of 90 min in six men. During the first 45 min, blood was sampled by means of vacuum tubes only. During the second 45 min, sampling took place with a syringe via a rubber stopper, either using a tourniquet (n = 3) or flushing the cannula with heparinized saline. Three criteria were used to identify variations in the patterns of LH and FSH as true hormonal changes. First, a threshold was used which had to be exceeded by the difference between nadir and maximum values before a pulse could be identified. An average of approximately six pulses per 90 min was found in both the LH and FSH series. The majority of these pulses lasted less than 3–4 min. In two subjects, larger LH pulses of longer duration were measured. Secondly, differences between duplicate measurements of nadir and/or maximum values of more than one-third of the amplitude of a pulse were considered unacceptable. This involved about 75% of the pulses. Thirdly, the reproducibility of the hormone variations was estimated. In one subject, concentrations of LH were measured four times in four separate assays. Measurement of FSH concentrations in this subject and of LH and FSH in the samples from the other five subjects were repeated once again, but only in those parts of the series of samples which had shown hormone variations beyond the threshold composed of acceptable duplicate measurements. Only the larger variations of longer duration, as found earlier in two of the LH series, were reproducible. The different blood-sampling techniques used had no significant influence on the frequency of pulses. It was concluded that a rapid, small amplitude, pulsatile pattern of release of LH and FSH is probably not present in men or is obscured by limitations of current techniques of radioimmunoassay. J. Endocr. (1987) 114, 153–160
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Guo, Zhaoyang, Junyan Yi, Sainan Xie, Jianpeng Chu, and Decheng Feng. "Study on the Influential Factors of Noise Characteristics in Dense-Graded Asphalt Mixtures and Field Asphalt Pavements." Shock and Vibration 2018 (August 28, 2018): 1–13. http://dx.doi.org/10.1155/2018/5742412.
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Determining the influential factors of noise characteristics in dense-graded asphalt mixtures and field asphalt pavement is important in constructing highways that are both low noise and environmentally friendly. In this study, the effects of nominal maximum aggregate size, asphalt binder type, air void percentage, and the service life of pavement on the noise absorption characteristics of asphalt mixtures were first investigated in laboratory. Thereafter, tire/pavement noise measurements were conducted on different types of dense-graded asphalt pavements. The effects of the service lives of the pavements, the types of the pavements, driving speeds, and test temperatures on the noise levels of the pavements were also studied. The Zwicker method is used to calculate psychoacoustic parameters on the tire/pavement noise spectrum. The laboratory results indicate that reducing the nominal maximum aggregate size, using rubber asphalt, and increasing air void percentage as well as surface texture depth improve the sound absorption performance of asphalt mixtures. The field measurements show that laying down asphalt pavements with a shorter service life or larger texture depth, using rubber asphalt, reducing traffic speed, and increasing air temperature can reduce noise.
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Wróbel, Jakub, and Damian Pietrusiak. "Noise Source Identification in Training Facilities and Gyms." Applied Sciences 12, no. 1 (December 22, 2021): 54. http://dx.doi.org/10.3390/app12010054.
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This paper deals with noise problems in industrial sites adapted for commercial training venues. The room acoustics of such an object were analyzed in the scope of the reverberation time and potential acoustic adaptation measures are indicated. Identification and classification of noise sources in training facilities and gyms was carried out based on the acoustic measurements. The influence of rubber padding on impact and noise reduction was investigated in the case of chosen noise-intensive exercise activities performed in a previously described acoustic environment. Potential noise reduction measures are proposed in the form of excitation reduction, vibration isolation, and room acoustics adaptation.
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Stoian, Elena Valentina, Jana Pintea, Maria Cristiana Enescu, and Carmen Otilia Rusanescu. "Experimental Results of Siloxanes Rubber Reinforced with Magnetic Fillers Used to Protect the Uman Factor to Electromagnetic Radiation." Materiale Plastice 56, no. 1 (March 30, 2019): 205–9. http://dx.doi.org/10.37358/mp.19.1.5152.
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The character of the original paper is to provide electromagnetic radiation absorbing material that attenuation characteristics of the electromagnetic field very good, as compared to the absorbent materials studied to date. This paper presents results of research on processing, characterization and behavior of composite materials based on silicone rubber used for electromagnetic shielding. In this work silicone rubbers is reinforced with magnetic fillers (iron silicon). The obtaining of composite materials was with the aid of a doctor blade technique. Doctor blade technique is a coating technique widely used for producing thin films on large area surfaces. The samples were processed in the laboratory using a plated nettling (PN), that was impregnated with a silicone rubber based composite containing powder of iron silicon (SI). Were achieved measurements of the both parts of the materials obtaining. These have shown an electromagnetic shielding effectiveness the order of 3.35-41.62 dB (white face) and 3.53-41.42 dB (gray face), in 1-18 GHz frequency range according to SR EN 50 147-1:1999. The paper tries to identify an absorbent material with the ability to protect human beings of electromagnetic radiation that surround us every day and every moment. With the exponential increase in development of commercial, aerospace, military and scientific electronic devices in modern society, electromagnetic radiation is becoming the fourth public pollution after the air, water and noise ones.
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Zhang, Bo, Shu Shan Wang, Meng Yu Cao, and Yu Xin Xu. "Design and Research of Wind Tunnel Test for Deflectable Nose." Applied Mechanics and Materials 423-426 (September 2013): 2063–67. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.2063.
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A wind tunnel test is designed to study aerodynamic effects of one individual rocket with deflectable nose. The test measures pressure with U-bend tube which is cost effective. Using rubber tubes in different lengths to measure pressure distributions of a flat-plate, and calculating how rubber tube affects the measurement, in order to modify the measured surface pressure of the nose. The surface pressure varies on different points while yawing angle and attack angle changes, the changing regularity could provide data for following numerical simulation and trajectory control.
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Lattimer, Robert P. "Tandem Mass Spectrometry (MS/MS) for Analysis of Additives in a Rubber Vulcanizate." Rubber Chemistry and Technology 61, no. 4 (September 1, 1988): 658–68. http://dx.doi.org/10.5254/1.3536211.
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Abstract MS/MS appears to have considerable potential as a means for improved direct mass spectral characterization of organic additives in rubber compounds. In this report, we have shown how daughter-ion, parent-ion, and neutral-loss scans can improve the specificity for identification of organic additive components in rubber vulcanizates. The use of MS/MS to reduce the “chemical noise” in the direct analysis of complex mixtures is demonstrated. MS/MS should not be viewed as a technique that will replace other mass spectral methods in rubber applications. For example, desorption ionization methods, GC/MS, LC/MS and high-resolution mass measurements will still have important roles. MS/MS can serve as a supplemental tool for direct mixture analysis that is both rapid and powerful.
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Bortnowski, Piotr, Robert Król, Anna Nowak-Szpak, and Maksymilian Ozdoba. "A Preliminary Studies of the Impact of a Conveyor Belt on the Noise Emission." Sustainability 14, no. 5 (February 27, 2022): 2785. http://dx.doi.org/10.3390/su14052785.
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This article performs a comparative analysis of noise generated by conveyor belts with different design parameters. The study was conducted for belts with the same tensile strength, differing in the physical parameters of the cover rubber. Noise emission measurements were performed on a laboratory belt conveyor. The test on the stand allowed for the determination of the noise emission as a function of variable operating parameters: the tensioning force and linear speed of the belt. Research results indicated a significant impact of speed on the emitted noise. The effect of belt tension on noise emission is small, and it is definitely less significant than the effect of linear speed. The results also show that it is possible to select a conveyor belt that emits less noise under the same operating conditions. The analysis of the results allowed us to determine the impact of the physical parameters of the belt covers on the emitted noise.
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Özel, Muhammed Abdullah, Selim Sefa Baysal, and Cemil Sungur. "Development of a Test System to Make Circularity Measurements of Rubber Bushing After Stress Relief." Tehnički glasnik 16, no. 4 (September 26, 2022): 546–49. http://dx.doi.org/10.31803/tg-20220329135150.
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Rubber metal bushings are one of the most important parts of the suspension system. These parts are specially designed to minimize the vibrations and noises that vehicles are exposed to while driving. In this study, it is aimed to measure the circularity of rubber metal bushings after stress relief. A modular design is provided according to the tolerance values of the bushings in the inventory. Simultaneously with deep learning and image processing algorithms, laser circularity measurements are verified with reference to bush circularity and deformation points are determined. The detected deformation is transferred to the HMI screen. With this study, it was ensured that the circularity errors in the rubber metal bushings were taken under control and the problems that may be encountered after the production were eliminated, a more sensitive solution was provided, and a quality production and accurate results were obtained.
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Merideno, Inaki, Javier Nieto, Nere Gil-Negrete, Aitor Landaberea, and Jon Iartza. "Constrained Layer Damper Modelling and Performance Evaluation for Eliminating Squeal Noise in Trams." Shock and Vibration 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/473720.
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This paper presents the modelling and design of a constrained layer damper to eliminate squeal noise in a particular tram. Even though resilient wheels are installed in every bogie, squeal noise is generated at the frequency of 780–800 Hz due to the small radius curves that the tram has to draw. Tuned constrained layer dampers provide a solution to this particular problem. Butyl rubber is chosen as the viscoelastic material for the damper, and conventional steel is used for the metallic sheets. The modelling approach and the final design of the damper are presented, together with evaluation of its performance in a real application. Experimental measurements on track have demonstrated that the constrained layer damper is properly tuned to the squealing frequency and that there is a significant reduction in noise when the proposed damper is attached to the wheels.
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Sambucci, Matteo, Abbas Sibai, Luciano Fattore, Riccardo Martufi, Sabrina Lucibello, and Marco Valente. "Finite Element Multi-Physics Analysis and Experimental Testing for Hollow Brick Solutions with Lightweight and Eco-Sustainable Cement Mix." Journal of Composites Science 6, no. 4 (April 5, 2022): 107. http://dx.doi.org/10.3390/jcs6040107.
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Combining eco-sustainability and technological efficiency is one of the “hot” topics in the current construction and architectural sectors. In this work, recycled tire rubber aggregates and acoustically effective fractal cavities were combined in the design, modeling, and experimental characterization of lightweight concrete hollow bricks. After analyzing the structural and acoustic behavior of the brick models by finite element analysis as a function of the type of constituent concrete material (reference and rubberized cement mixes) and hollow inner geometry (circular- and fractal-shaped hollow designs), compressive tests and sound-absorption measurements were experimentally performed to evaluate the real performance of the developed prototypes. Compared to the traditional circular hollow pattern, fractal cavities improve the mechanical strength of the brick, its structural efficiency (strength-to-weight ratio), and the medium–high frequency noise damping. The use of ground waste tire rubber as a total concrete aggregate represents an eco-friendlier solution than the ordinary cementitious mix design, providing, at the same time, enhanced lightweight properties, mechanical ductility, and better sound attenuation. The near-compliance of rubber-concrete blocks with standard requirements and the value-added properties have demonstrated a good potential for incorporating waste rubber as aggregate for non-structural applications.
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Andargie, Maedot S., Marianne Touchie, and William O'Brien. "Subjective and objective evaluation of the impact and airborne sound insulation of multi-unit residential buildings." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 6 (August 1, 2021): 778–86. http://dx.doi.org/10.3397/in-2021-1648.
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Multi-unit residential building (MURB) occupants often express dissatisfaction with their suites' acoustic conditions despite existing building acoustic standards and regulations as well as growing research on noise control and building acoustics. Reasons for this include the lack of proper characterization of acoustic comfort in MURBs and lack of comprehensive and stringent regulations. To better understand factors that impact acoustic comfort and explore strategies to improve the acoustic performance of MURBs, investigations of acoustic conditions were carried out. This work presents the results of the investigations which include subjective and objective evaluations of acoustic conditions in two MURBs. Impact sound insulation measurements using both a tapping machine and a rubber ball as well as 24-hour indoor noise monitoring were carried out in unoccupied suites. An online survey was then used to collect subjective assessments of the noise conditions in the buildings and the effects on occupants' comfort post occupancy. Results of the data analysis suggest that occupants are more sensitive to low-frequency impact sounds than mid- and high-frequency impact noise.
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Li, Qi, and David J. Thompson. "Prediction of rail and bridge noise arising from concrete railway viaducts by using a multilayer rail fastener model and a wavenumber domain method." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 5 (July 20, 2017): 1326–46. http://dx.doi.org/10.1177/0954409717720839.
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Concrete viaducts are an important part of urban rail transit systems but they produce considerable noise, thereby affecting the communities living nearby. The vibration generated at the wheel–rail interface is transmitted along the rail and also onto the bridge; hence, noise is radiated from both the rail and the bridge. To facilitate noise prediction, it is desirable to develop a model that takes into account the generation and transmission of vibration in the train–track–bridge system. The vibration and the associated noise of the track–bridge system are computed with a unified vibroacoustic model using a wavenumber domain finite element and boundary element method. An important aspect to note is the frequency-dependent stiffness of a typical rail fastener utilized on bridges due to the resonance of the baseplate between the two rubber pads. In this study, to allow for this effect, a multilayer fastener model is proposed. The proposed procedure is applied to a viaduct with a U-shaped section and compared with field measurements during the passage of trains. The elastic modulus and damping of the rubber pads and the equivalent loss factor of the rail are chosen by fitting the calculated track decay rates to those estimated from the measured rail accelerations under train passages. The wheel–rail combined roughness is also derived from the measured rail vibration. A comparison is then made between the simulated and measured bridge vibration to verify the proposed method as well as the parameters used in the track–bridge system. The predicted noise levels are also compared with the measured results. The effects of the fastener model, fastener stiffness, bridge damping, and interference between multiple wheels are then discussed. It has been found that the bridge noise has a non-negligible effect on the total A-weighted noise levels in the region beneath the bridge and up to 30 m away from the track.
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Jakob, André, Rudi Volz, and Michael Möser. "Investigation of the Physical Mechanism of Walking Noise Radiation of Laminate Floor-Coverings." Building Acoustics 12, no. 3 (September 2005): 141–63. http://dx.doi.org/10.1260/135101005774353087.
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This paper reports on an investigation of the physical mechanism of walking noise radiated by laminate floor coverings with and without backings. In pretests of single laminate panels the influence of different backings on the structural vibration of the panels was determined and material parameters like Young's modulus and bending stiffness were obtained. From these parameters the coincidence frequency could be estimated. The main tests were performed with hard rubber balls falling on laminate floor coverings of different sizes and with different backings. Results show that the radiated sound has a single frequency maximum, which is far below the coincidence frequency. From this and from confirming sound intensity measurements it follows that the sound radiation is a locally constrained phenomenon. Additionally, vibration measurements show that the near field of bending waves dominates the vibration and bending wave propagation can be neglected. The characteristics of the near field vibration and therefore the sound radiation can be controlled by the choice of backing of the laminate floor covering.
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Stodola, Jiří, and Petr Stodola. "Noise Reduction in the Cab of a Special Vehicle." Defence Science Journal 72, no. 3 (July 1, 2022): 450–58. http://dx.doi.org/10.14429/dsj.72.17127.
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Noise is highly associated with adverse effects on health, the human psyche and performance. Current special vehicles do not possess sufficient technologies to suppress the transmission of noise or vibration, which typically results in loss of control, comfort, driving safety, the performance of tasks, etc. At the same time, noise reduces attention and work efficiency while increasing fatigue, leading to hazards, dangerous situations, and missions that may not be completed. This article briefly presents selected parts of a project which included additional soundproofing of a special armoured mobile vehicle on a TATRA wheeled chassis. Basic theoretical, experimental, and practical information about this project is presented. To reduce noise, a selected damping material was used, which is a combination of recycled PUR foam and black rubber with a rough structure. The damping material was selected based on repeated experimental testing of sound absorption measurements from several damping materials. The material was chosen for suitable damping effects and corresponding technological properties (resistance to high temperatures, non-flammability, etc.). In the engine compartment and the cab of the vehicle, the damping properties were experimentally verified after retrofitting, while the noise was significantly reduced.
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Meegahapola, Pubuduni Anuradha, and R. A. Ranga Prabodanie. "Impact of environmental conditions on workers’ productivity and health." International Journal of Workplace Health Management 11, no. 2 (April 3, 2018): 74–84. http://dx.doi.org/10.1108/ijwhm-10-2017-0082.
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Purpose Some manufacturing processes generate extreme temperatures, noise and other irritating environmental conditions. These environmental factors can have a negative impact on workers’ performance and health. The purpose of this paper is to investigate the impact of temperature, noise and lighting on factory workers’ productivity and day-to-day health in a rubber compound manufacturing plant. Design/methodology/approach Secondary data on productivity, measurements of factory environmental conditions, and records of medical advice and treatments over a period of three months were used in this study. Causal analysis was performed using statistical techniques ANOVA and regression analysis in SPSS statistical package. Findings The results revealed that higher levels of temperature and noise inside the factory can cause lower productivity levels. High temperature may not only reduce the productivity but also contribute to illnesses or heat-stress symptoms such as headaches. The results further suggested that both noise and lighting level do not have a statistically significant impact on workers’ health. No statistical evidence was found on lighting level having an impact on workers’ productivity. Research limitations/implications The study was particularly focused on a rubber compound manufacturing plant. However, the results were consistent with the results obtained in similar studies which focused on leather and shoe industry and automobile assembly industry. Originality/value The impact of environmental conditions on workers’ performance and health has been studied with respect to few industries and regions. This is the first of that kind carried out in Sri Lanka. Clear evidence of productivity losses and health impacts caused by high temperatures, raises the need for improving the working conditions.
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Bettarello, Federica, Andrea Gasparella, and Marco Caniato. "The Influence of Floor Layering on Airborne Sound Insulation and Impact Noise Reduction: A Study on Cross Laminated Timber (CLT) Structures." Applied Sciences 11, no. 13 (June 25, 2021): 5938. http://dx.doi.org/10.3390/app11135938.
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The use of timber constructions recently increased. In particular, Cross Laminated Timber floors are often used in multi-story buildings. The development of standardization processes, product testing, design of details and joints, the speed of construction, and the advantages of eco-sustainability are the main reasons why these structures play a paramount role on the international building scene. However, for further developments, it is essential to investigate sound insulation properties, in order to meet the requirements of indoor comfort and comply with current building regulations. This work presents the results obtained by in field measurements developed using different sound sources (tapping machine, impact rubber ball, and airborne dodecahedral speaker) on Cross Laminated Timber floors, changing different sound insulation layering (suspended ceiling and floating floors). Results clearly show that the influence on noise reduction caused by different layering stimulated by diverse noise source is not constant and furthermore that no available analytical model is able to correctly predict Cross Laminated Timber floors acoustic performances.
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Massi, Francesco, Eric Vittecoq, Eric Chatelet, Aurelien Saulot, and Yves Berthier. "Design of a tribometer for investigating tactile perception." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 232, no. 6 (January 20, 2014): 773–84. http://dx.doi.org/10.1177/1350650113518906.
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The understanding of the tactile perception mechanism implies the reproduction and measurement of friction forces and vibrations induced by the contact between the skin of human fingers and object surfaces. When a finger moves to scan the surface of an object, it activates the receptors located under the skin allowing the brain to identify surfaces and information about their properties. The information concerning the object surface is affected by the forces and vibrations induced by the friction between the skin and the rubbed object. The vibrations propagate in the finger skin and are converted into electric impulses sent to the brain by the mechanoreceptors. Because of the low amplitude of the induced vibrations, it results quite hard to reproduce the tactile surface scanning and measuring it without affecting measurements by external noise coming from the experimental test-bench. In fact the reproduction of the sliding contact between two surfaces implies the relative motion between them, which is obtained by appropriate mechanisms having a more or less complicated kinematics and including several sliding surfaces (bearings, sliders, etc.). It results quite difficult to distinguish between the vibrations coming from the reproduced sliding and the parasitic noise coming from the other sliding contact pairs. This paper presents the design and validation of a tribometer, named TRIBOTOUCH, allowing for reproducing and measuring friction forces and friction induced vibrations that are basilar for a clear understanding of the mechanisms of the tactile sense.
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Goossens, Joshua R., and William V. Mars. "FINITELY SCOPED, HIGH RELIABILITY FATIGUE CRACK GROWTH MEASUREMENTS." Rubber Chemistry and Technology 91, no. 4 (October 1, 2018): 644–50. http://dx.doi.org/10.5254/rct.18.81532.
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ABSTRACT Classical procedures for characterizing fatigue crack growth behavior often suffer from uncertainties that make it difficult to plan for productive use of test instrument time, and that can result ultimately in too noisy measurements. An enhanced procedure has been implemented that is based on a fixed test time budget, and that establishes operating conditions that produce crack growth rates down to minimum measurable rates. The procedure features (1) a haversine pulse deformation test cycle followed by a rest period, (2) a strain peak that ramps linearly over time, (3) minimum and maximum limits on the strain peak chosen to avoid unproductive test time, and (4) a stress–strain probe cycle for purposes of observing strain energy density. A set of replicates of a carbon black filled, natural rubber bushing compound has been characterized via both procedures, and a statistical analysis is made to compare both. The new procedure significantly improves the quality of crack growth rate curve measurements.
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Zhang, Ji Tang, and Bin Bin Peng. "The Application Research of Amplitude Spectrum in the Coating Layer Thickness Detection." Applied Mechanics and Materials 55-57 (May 2011): 802–6. http://dx.doi.org/10.4028/www.scientific.net/amm.55-57.802.
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The caoting layer of each industry structure detected by ultrasonic testing is one commonly used thickness detection technique. This article proposed a method which used the extreme value of resonant amplitude spectrum to extract the thickness feature value, it can solve the feature value extraction difficult question which caused by two situations of time domain signals aliasing when the coating layer thickness is quite small and signals weak when signal attenuates seriously. And when the extreme point distributed unevenly in the actual detection, some measurements to improve the feature value extraction precision are proposed, which increased the detection signal-to-noise rated effectively. Take the structure of steel shell bonding rubber coating layer as the detection object, the detection experiment is studied to confirm its validity.
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Granzotto, Nicola, Arianna Marzi, and Andrea Gasparella. "Cross-Laminated Timber Floor: Analysis of the Acoustic Properties and Radiation Efficiency." Applied Sciences 12, no. 7 (March 22, 2022): 3233. http://dx.doi.org/10.3390/app12073233.
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Cross-Laminated Timber (CLT) is a building technology that is becoming increasingly popular due to its sustainable and eco-friendly nature, as well as its availability. Nevertheless, CLT presents some challenges, especially in terms of impact noise and airborne sound insulation. For this reason, many studies focus on the vibro-acoustic behavior of CLT building elements, to understand their performance, advantages and limitations. In this paper, a 200 mm CLT floor has been characterized in the laboratory, according to ISO standards, by three noise sources: dodecahedron, standard tapping machine and rubber ball. In order to understand the vibro-acoustic behavior of the CLT floor, measurements through the analysis of sound pressure levels and velocity levels, measured by dedicated sensors, were performed. Analysis was carried out in order to understand what is prescribed by the prediction methods available in the literature and by the simulation software. Then, a specific prediction law for the CLT floor under investigation was derived. Finally, an analysis on sound radiation index is provided to complete the vibro-acoustic study.
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Sekitani, Tsuyoshi. "(Invited, Digital Presentation) Ultra-Thin Organic Integrated Circuits Enabling Bio-Signal Monitoring." ECS Meeting Abstracts MA2022-01, no. 10 (July 7, 2022): 799. http://dx.doi.org/10.1149/ma2022-0110799mtgabs.
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Digital technology has permeated our society, and a wide variety of electronic devices are now in use. In particular, the development of electronic devices for biometric measurements, such as wearable electronics, has been remarkable, and coupled with research and development of high-speed communication and artificial intelligence (AI), many social implementations are being presented. Our group has been conducting research and development on flexible and stretchable electronic systems, which are flexible, soft like rubber, and lightweight, by integrating functional organic nano-materials. In this research activity, our flexible and stretchable electronics have obtained certification for medical devices and are promoting the development of new electronics for use in medical institutions. In this presentation, I would like to introduce our recent activities on the flexible and stretchable electronics utilizing the nanoscience and technology, and developed low-noise and ultra-flexible systems for measuring biological action potentials (electroencephalogram; EEG and electrocardiogram ; ECG).
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Zhao, Caiyou, Ping Wang, Qiang Yi, and Duo Meng. "Viability Analysis of Waste Tires as Material for Rail Vibration and Noise Control in Modern Tram Track Systems." Shock and Vibration 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/725808.
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This research study focused on the effect of using damping chamber elements made from waste tires on railway noise reduction. First, the energy absorption characteristics of damping chamber elements with various gradation combinations and compaction indices were measured in the laboratory using compression testing. The laboratory compression results demonstrated that the optimal gradation combination of damping chamber elements is as follows: the content of fine rubber particles is 10%, the content of coarse granules is 90%, and the optimal compaction index is 0.98. Next, the findings from the laboratory compression-test studies were used to produce damping chamber elements that were applied to a full-scale modern track model in the laboratory. The measurements of the dynamic properties indicated that the damping chamber elements could significantly reduce the vibration levels of the rail head. Finally, the damping chamber elements, which had been proven effective through laboratory dynamic tests, were widely applied to test rail sections in the field. The field tests demonstrated that damping chamber elements can significantly increase the track vibration decay rate in the frequency range of 200–10000 Hz. Therefore, damping chamber elements made from waste tires are able to control rail vibration and noise in modern tram track systems.
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Sangirardi, Marialuigia, Vittorio Altomare, Stefano De Santis, and Gianmarco de Felice. "Detecting Damage Evolution of Masonry Structures through Computer-Vision-Based Monitoring Methods." Buildings 12, no. 6 (June 14, 2022): 831. http://dx.doi.org/10.3390/buildings12060831.
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Detecting the onset of structural damage and its progressive evolution is crucial for the assessment and maintenance of the built environment. This paper describes the application of a computer-vision-based methodology for structural health monitoring to a shake table investigation. Three rubble stone masonry walls, one unreinforced and two reinforced, were tested under natural earthquake base inputs, progressively scaled up to collapse. White noise signals were also applied for dynamic identification purposes. Throughout the experiments, videos were recorded, under both white noise excitation and environmental vibrations, with the table at rest. The videos were preprocessed with motion magnification algorithms and analyzed through a principal component analysis. The natural frequencies of the walls were detected and their progressive decay was associated with damage accumulation. Results agreed with those obtained from another measurement system available in the laboratory and were consistent with the crack pattern development surveyed during the tests. The proposed approach proved useful to derive information on the progressive deterioration of the structural properties, showing the feasibility of this methodology for real field applications.
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Clet, Jing Angelo Gonzaga, Nai-Shang Liou, Chen-Hsun Weng, and Yu-Sheng Lin. "A Parametric Study for Tensile Properties of Silicone Rubber Specimen Using the Bowden-Type Silicone Printer." Materials 15, no. 5 (February 25, 2022): 1729. http://dx.doi.org/10.3390/ma15051729.
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Silicone printing can enable a lot more accessibility and customizability towards utilizing silicone in different applications, including medicine for its biocompatibility. However, challenges existed for printing in specific geometries due to the lack of guidelines and studies on the mechanical properties. To support the understanding of printing three-dimensional silicone structure having different infill patterns and gel-like material, this paper conducted a parametric study for the specimens printed using a Bowden-type silicone printer and measurements of the tensile properties. Four printing parameters of print speed, infill density, flow rate, and infill pattern, are categorized following the Taguchi L9 method, and arranged into the four-parameter-three-level orthogonal array. The signal-to-noise (S/N) ratio was calculated based on the principle of the-larger-the-better, and analysis of variance (ANOVA) was also obtained. Tensile performance was further discussed with the characterization of internal structure, using the cross-sections of the printed specimens. It was found that the change of flow rate is the most significant to the tensile stress; and for the tensile strain, infill pattern was found to be the most significant parameter. The Line infill pattern consistently presented the highest tensile stress. Agglomeration can be seen inside the printed structure, hence optimal printing parameters play an important role for complicated geometry, while ensuring the flow rate and infill density do not exceed a reasonable value. This study would serve as the guideline for printing three-dimensional silicone structures.
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Gardziejczyk, Wladyslaw, Piotr Jaskula, Jerzy A. Ejsmont, Marek Motylewicz, Marcin Stienss, Piotr Mioduszewski, Pawel Gierasimiuk, and Maciej Zawadzki. "Investigation of Acoustic Properties of Poroelastic Asphalt Mixtures in Laboratory and Field Conditions." Materials 14, no. 10 (May 18, 2021): 2649. http://dx.doi.org/10.3390/ma14102649.
Full textAbstract:
Measures for the improvement of acoustic conditions in the vicinity of roads include the construction of pavement structures with low-noise surfaces with optimal macrotexture and the highest possible sound absorption coefficient. Laboratory evaluation of acoustic properties of a designed asphalt mixture before its placement in the pavement is a good solution. Currently, the most popular method for the determination of the sound absorption coefficient of various construction materials under laboratory conditions is the Kundt’s tube test. Sound absorption coefficient can also be assessed based on field and laboratory measurements performed using a Spectronics ACUPAVE System. Other parameters characterising the acoustic properties of road pavement courses include air void content and water drainability or permeability. The article presents an analysis of results of sound absorption coefficient obtained using a Spectronics ACUPAVE System and water drainability and permeability of poroelastic mixtures obtained both in laboratory and on test sections, in relation to air void content and grading of the mixtures. It was established that poroelastic mixtures containing an aggregate of maximum particle size of 5 mm are characterised by better acoustic properties than mixtures with a maximum aggregate particle size of 8 mm. Changes of crumb rubber aggregate grading and bitumen type (within the tested range of values) as well as the addition of lime have shown no evident influence on the sound absorption coefficient. Noise level values at the speed of 30 km/h according to the CPX method were measured as well. Relationships between sound absorption coefficient, water drainability/permeability, and air void content were determined. The performed analyses confirmed that Spectronics ACUPAVE System may be applied for evaluation of acoustic properties of asphalt mixtures in laboratory conditions, but further research is needed to reduce the uncertainty of the results.
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Hiroe, Masaaki, and Nozomu Taniguchi. "NOISE REDUCTION DUE TO VIBRATION DAMPING ESTIMATED BY MEASUREMENTS OF PARTICLE VELOCITY." Proceedings of International Structural Engineering and Construction 5, no. 2 (December 2018). http://dx.doi.org/10.14455/isec.res.2018.113.
Full textAbstract:
We proposed a new method to evaluate noise reduction due to damping treatment by using the particle velocity of sound measured directly in the vicinity of a vibrating object. Moreover, the proposed method was verified based on the comparison between vibration and particle velocity reductions. In Japan, a procedure to revamp old railway bridges, which had no specific fissure damages or serious corrosions, by applying to composite remodeling process have been widely used. During the process of such composite remodeling, we have often used magnetic rubber damper or rubber-latex mortar to reduce remarkable large power of structure-borne sound radiated from steel bridge of railway. This proposed method enables us to estimate precisely noise reduction of these countermeasures, because we grasp the behavior of sound radiated from the vibrating object in detail. In this paper, we present the results of laboratory and field experiments on the effects of noise reduction by using two magnetic rubber dampers, type-A and type-B. In the field measurement, the type-B more significantly reduced the sound radiated from vibrating beam. However, the reduction of radiated sound and that of vibration did not coincide. The reason was clarified from comparison between vibration and particle velocity, which occur due to vibrating a steel plate of simulated beam of bridge in laboratory experiment. Thus, the proposed method enables us to evaluate noise reduction precisely.
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Fujimori, Mikiya, Shinya Takemae, and Yosuke Tanaka. "Sensitivity improvement of submicron dynamic displacement measurement system composed of phase-modulated fiber optic interferometer." Japanese Journal of Applied Physics, March 23, 2022. http://dx.doi.org/10.35848/1347-4065/ac6055.
Full textAbstract:
Abstract We investigated sensitivity improvement of a dynamic displacement measurement system composed of a phase-modulated fiber optic interferometer and a spatial optical system. We introduced a balanced photodetector to enhance the signal-to-noise ratio of the interference signal. The newly developed system was evaluated by using pseudo vibration made by a phase modulator and was proved to be able to measure the dynamic displacement with a high-frequency vibration of 100 kHz even when the reflected power from a sample was -50 dBm. We also performed experiments using a rubber or a mouse’s ear bone attached to a PZT driven by 100 kHz sinusoidal signal and successfully confirmed that vibration with an amplitude of less than 10 nm was clearly observed even when a reflected optical power was –46.9 dBm.
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Zhou, Xin, Shuoqiao Zhong, and Xiaozhen Sheng. "An investigation into the effect of resilient wheel stiffness on the dynamic behaviour of a metro vehicle running along a tangent track." Journal of Vibration and Control, May 6, 2022, 107754632210948. http://dx.doi.org/10.1177/10775463221094892.
Full textAbstract:
Resilient wheels are extensively used for trams due to the noise reduction they can achieve. However, the effect of the resilient wheels on vehicle dynamics has not been adequately studied. An effort is presented in this paper, trying to bridge this gap. To simulate interactions between vehicle and track, the resilient wheel is modelled as a multi-rigid body system consisting of a rigid wheel core and a rigid rim between which a rubber layer is inserted. The rubber layer is regarded as three-directional spring-damper units, allowing the rim and core to have relative motions, so that the flexibility of the resilient wheel provided by the rubber layer is fully simulated. Then, the dynamics of a vehicle-track coupling system integrated with this resilient wheel model is simulated and compared with in-situ measurement. The simulation results show that, compared with a conventional solid wheel, the vertical vibration of the wheel core is much reduced in the frequency range of 70–300 Hz while the lateral vibration is much reduced in the frequency range of 90–300 Hz. The paper continues with the recommendation of the radial and axial stiffnesses, two key parameters of the resilient wheel, aiming to lower the wheel-rail contact force and carbody vibration.