• Bulletin of the Korean Chemical Society
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• v.24 no.7
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• pp.986-992
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• 2003

We have calculated the probability of the OH formation and energy deposit of the reaction exothermicity in the newly formed OH, particularly in its vibrational motion, in the gas-surface reaction O(g) + H(ad)/Si → OH(g) + Si on the basis of the collision-induced Eley-Rideal mechanism. The reaction probability of the OH formation increases linearly with initial excitation of the HSi vibration. The translational and vibrational motions share most of the energy when the H-Si vibration is initially in the ground state. But, when the initial excitation increases, the vibrational energy of OH rises accordingly, while the energies shared by other motions vary only slightly. The product vibrational excitation is significant and the population distribution is inverted. Flow of energy between the reaction zone and the solid has been incorporated in trajectory calculations. The amount of energy propagated into the solid is only a few percent of the available energy released in the OH formation.

• Advances in nano research
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• v.11 no.6
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• pp.641-648
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• 2021

In this article, the dynamic parameters (frequencies, mode shapes, damping ratios) of the scaled concrete structure and the dynamic parameters (frequencies, mode shapes, damping ratios) of the entire outer surface of titanium dioxide, 80 micron in thickness are compared using operational modal analysis method. Ambient excitation was provided from micro tremor ambient vibration data on ground level. Enhanced Frequency Domain Decomposition (EFDD) was used for the output only modal identification. From this study, a good correlation between mode shapes was found. Titanium dioxide applied to the entire outer surface of the scaled concrete structure has an average of 11.78% difference in frequency values and 10.15% in damping ratios, proving that nanomaterials can be used to increase rigidity in structures, in other words, for reinforcement. Another important result determined in the study was the observation of the adherence of titanium dioxide and similar nanomaterials mentioned in the introduction to concrete structure surfaces was at the highest level.

• Advances in nano research
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• v.12 no.1
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• pp.65-72
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• 2022

The dynamic properties (frequencies, mode shapes, damping ratios) of the scaled WPC warehouse are compared using the operational modal analysis approach to the dynamic parameters (frequencies, mode shapes, damping ratios) of the full outer surface of titanium dioxide, 70 micron in thickness. Micro tremor ambient vibration data on ground level was used to provide ambient excitation. For the output-only modal identification, Enhanced Frequency Domain Decomposition (EFDD) was used. This study discovered a strong correlation between mode shapes. Titanium dioxide applied to the entire outer surface of the scaled WPC warehouse results in an average 14.05 percent difference in frequency values and 7.61 percent difference in damping ratios, demonstrating that nanomaterials can be used to increase rigidity in structures, or for reinforcement. Another significant finding in the study was the highest level of adherence of titanium dioxide and similar nanomaterials mentioned in the introduction to WPC structure surfaces.

• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.278-285
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• 2013

The suppression of residual settlement is required on earthwork sections as concrete track is introduced. Use of pile-slab structure is one of the settlement restraining methods applied on soft ground. The slab distributes the upper embankment load and piles transfer the load from the slab to the stiff ground. While this method is very effective in terms of load transfer, it has not yet been established for dealing with the vibration transfer effects and interaction characteristics between a structure and the ground. It is possible that vibration caused by a moving train load is propagated in the upper embankment, because the slab acts as a reflection layer and waves are multi-reflected. In this present paper, wave propagation generated by a moving train load is evaluated in the time and frequency domains to consider a roadbed structure using an artificial impact load and field measured train load. The results confirmed the wave reflection effect on the pile-slab structure, if the embankment height is sufficient, vibration propagation can be stably restrained, whereas if the height is not sufficient, the vibration amplitude is increased.

• Explosives and Blasting
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• v.38 no.2
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• pp.22-35
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• 2020

Recently, electronic detonators have been widely used in various sites. Electronic detonators are often used for the purpose of reducing the noise and vibration produced by blasting. In addition, electronic detonators are used for precision blasting at sites where mechanical excavation techniques are applied due to proximity of safety things or where blasting by conventional detonators are not possible. Various technologies are being attempted at the blasting site to increase constructivity and lower production costs by using electronic detonators. In this paper, we would like to introduce a construction case that use of electronic detonators in the situation of safety things being adjacent increases the efficiency of construction while meeting the ground vibration criteria of Ministry of Land, Infrastructure, and Transport. The blasting was carried out at domestic and overseas shaft using HiTRONIC II™, produced by Hanwha. Generally the shaft blasting is performed by dividing the blasting surface because of the noise and vibration caused by the blasting. but, in the case introduced in this paper, the blasting was carried out once without dividing the blasting surface, thus the construction period could be shortened.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.4
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• pp.199-205
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• 2021

The distributing board in directly installed on the ground or the bottom surface of the building, and when vibrations such as earthquakes or external shocks occur, the possibility of damage or malfunction of electric components such as internal power devices, wiring, and protection relays increases. Recently, the need for a seismic type distributing board is increasing, and research and development of a distributing board having a vibration damping function and product launch are being conducted. In this paper, an IoT-based data collection device system capable of measuring vibration and environmental data of distributing board was designed and implemented. When vibration occurred on the distributing board, data was stored and visualized in the MySQL DB through Node-RED for monitoring and data storage using the MQTT protocol for reliable messaging transmission. The test was conducted by attaching the IoT device of the distributing board, and data was collected in real-time and monitored through Node-RED.

• Journal of the Korean Society of Safety
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• v.17 no.3
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• pp.36-42
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• 2002

Structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, noise/vibration/harshness(NVH), crashworthiness and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer. In this study, we used the virtual proving ground(VPG) approach for obtaining the dynamic characteristics. VPG approach uses a nonlinear, dynamic, finite element code(LS-DYNA3D) which expands the application boundary outside the classic linear, antic assumptions. VPG approach also uses realistic boundary conditions of tire/road surface interactions. To verify the predicted dynamic results, a single lane change test has been performed. The prediction results were compared with the experimental test results, and the feasibility of the integrated CAE analysis methodology was verified.

• The Journal of Engineering Geology
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• v.1 no.1
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• pp.109-120
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• 1991

Applications of microtremor to geological engineering are widely reviewed and observed microtremors are processed to show evidences of close relationship between the predominant periods of microtremor and underground structure. The ground vibrates continuously at all times and the elastic vibration is called microtremor (0.5-20Hz) or microseisms (0.01-0.1Hz) according to their frequency range. The vibration is believed to have propagative nature like those of the dispersive surface waves or multireflected shear waves. Microtremors were recorded at selected thress places of which subsoil structures are well distinguished in the Kyongsang Sedimentary Basin. It is found that the underground structures estimated from microtremor analysis coincide well with the known structures. The microtremor analysis of the long period range can be an inexpensive and effective tool in geological engineering for the evaluation of the underground structure, site-specific reponse spectrum, and seismic microzonations.

• Explosives and Blasting
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• v.37 no.4
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• pp.1-9
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• 2019

In this study the applicability of a Digital Image Correlation (DIC) method was investigated by measuring the displacement and vibration of rock pillar due to underground mining blasting. When combined with a high speed photography technology, the DIC method provides an excellent photographic image processing ability that can be used to convert the evolving full-field surface properties of structures to 2D or 3D set of coordinate values. The measured coordinate sets are then used to calculate the displacement, strain, and velocity of the target structure. This technique is widely used in science and engineering, and continuously finds its new application areas. In this study, the DIC system and the conventional seismograph were compared for their ability to measure the displacement and vibration produced by blasting. In the field test both methods showed similar results. Thus, it is concluded that the DIC method is feasible to measure the ground displacements and vibrations from blasting.

• International Journal of Automotive Technology
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• v.6 no.1
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• pp.29-35
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• 2005

The structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, Noise/Vibration/Harshness (NVH), crashworthiness, and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer. In this study, the Virtual Proving Ground (VPG) approach has been developed to simulate dynamic nonlinear events as applied to automotive ride & handling. The finite element analysis technique provides a unique method to create and analyze vehicle system models, capable of including vehicle suspensions, powertrains, and body structures in a single simulation. Through the development of this methodology, event-based simulations of vehicle performance over a given three-dimensional road surface can be performed. To verify the predicted dynamic results, a single lane change test was performed. The predicted results were compared with the experimental test results, and the feasibility of the integrated CAE analysis methodology was verified.