• Geomechanics and Engineering
• /
• v.11 no.5
• /
• pp.607-624
• /
• 2016

Rockburst is becoming more serious in Chinese coal mine. One of the effective methods to control rockburst is blasting. In the paper, we monitored and analyzed the blasting waves at different blast center distances by the Hilbert-Huang transform (HHT) in a coal mine. Results show that with the increase of blast center distance, the main frequency and amplitude of blasting waves show the decreasing trend. The attenuation of blasting waves is slower in the near blast field (10-75 m), compared with the far blast field (75-230 m). Besides, the frequency superposition phenomenon aggravates in the far field. A majority of the blasting waves energy at different blast center distances is concentrated around the IMF components 1-3. The instantaneous energy peak shows attenuation trend with the blast center distance increase, there are two obvious energy peaks in the near blast field (10-75 m), the energy spectrum appears "fat", and the total energy is greater. By contrast, there is only an energy peak in the far blast field, the energy spectrum is "thin", and the total energy is lesser. The HHT three dimensional spectrum shows that the wave energy accumulates in the time and frequency with the increasing of blast center distance.

• Steel and Composite Structures
• /
• v.27 no.4
• /
• pp.417-426
• /
• 2018

This paper presents the seismic behaviors and restoring force model of ring beam joints of steel tube-reinforced concrete column structure under cyclic loading. First, the main failure mode, ultimate bearing capacity, stiffness degradation and energy dissipation capacity are studied. Then, the effects of concrete grade, steel grade, reinforcement ratio and radius-to-width ratios are discussed. Finally, the restoring force model is proposed. Results show that the ring beam joints of steel tube-reinforced concrete column structure performs good seismic performances. With concrete grade increasing, the ultimate bearing capacity and energy dissipation capacity increase, while the stiffness degradation rates increases slightly. When the radius-width ratio is 2, with reinforcement ratio increasing, the ultimate bearing capacity decreases. However, when the radius-to-width ratios are 3, with reinforcement ratio increasing, the ultimate bearing capacity increases. With radius-to-width ratios increasing, the ultimate bearing capacity decreases slightly and the stiffness degradation rate increases, but the energy dissipation capacity increases slightly.

• Safety and Health at Work
• /
• v.12 no.2
• /
• pp.286-287
• /
• 2021

• Structural Engineering and Mechanics
• /
• v.71 no.2
• /
• pp.109-118
• /
• 2019

This paper presents the numerical simulation of membrane structure under impact load. Firstly, the numerical simulation model is validated by comparing with the test in Hao's research. Then, the effects of the shape of the projectile, the membrane prestress and the initial impact speed, are investigated for studying the dynamic response and failure mechanism, based on the membrane displacement, projectile acceleration and kinetic energy. Finally, the results show that the initial speed and the punch shape are related with the loss of kinetic energy of projectiles. Meanwhile, the membrane prestress is an important factor that affects the energy dissipation capacity and the impact resistance of membrane structures.

• ETRI Journal
• /
• v.35 no.6
• /
• pp.1038-1047
• /
• 2013

Augmented reality (AR) is currently being applied actively to commercial products, and various types of intelligent AR systems combining both the Global Positioning System and computer-vision technologies are being developed and commercialized. This paper suggests an in-vehicle head-up display (HUD) system that is combined with AR technology. The proposed system recognizes driving-safety information and offers it to the driver. Unlike existing HUD systems, the system displays information registered to the driver's view and is developed for the robust recognition of obstacles under bad weather conditions. The system is composed of four modules: a ground obstacle detection module, an object decision module, an object recognition module, and a display module. The recognition ratio of the driving-safety information obtained by the proposed AR-HUD system is about 73%, and the system has a recognition speed of about 15 fps for both vehicles and pedestrians.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
• /
• 2001.10a
• /
• pp.95-99
• /
• 2001

• International Journal of Internet, Broadcasting and Communication
• /
• v.16 no.1
• /
• pp.140-147
• /
• 2024

In Current artificial structures, we must periodically make their safety inspections. In this process, we should consider the safety of workers and the accuracy of safety checks and also consider time and cost savings for safety inspections. Additionally, in the fields of architecture and civil engineering, we are unavoidable the use of foreign commercialized BIM model tools. To address these challenges, we propose mapping crack areas and BIM 3D design drawings based on augmented reality (AR) for the safety inspection of Huge Bridges. For this purpose, we define indexing of 2D/3D drawing models, create the tabulation of all 2D/3D drawings into a database, analyze QR codes, and finally integrate with augmented reality devices. we may expect our method to improve the efficiency of safety inspections on bridge sites. Moreover, we will enable the domestics of our pure technology.

• Asian-Australasian Journal of Animal Sciences
• /
• v.31 no.4
• /
• pp.548-555
• /
• 2018

Objective: This experiment was conducted to investigate whether asparagine (Asn) could improve liver energy status in weaning pigs when challenged with lipopolysaccharide. Methods: Forty-eight weaned pigs ($Duroc{\times}Large\;White{\times}Landrace$, $8.12{\pm}0.56kg$) were assigned to four treatments: i) CTRL, piglets received a control diet and injected with sterile 0.9% NaCl solution; ii) lipopolysaccharide challenged control (LPSCC), piglets received the same control diet and injected with Escherichia coli LPS; iii) lipopolysaccharide (LPS)+0.5% Asn, piglets received a 0.5% Asn diet and injected with LPS; and iv) LPS+1.0% Asn, piglets received a 1.0% Asn diet and injected with LPS. All piglets were fed the experimental diets for 19 d. On d 20, the pigs were injected intraperitoneally with Escherichia coli LPS at $100{\mu}g/kg$ body weights or the same volume of 0.9% NaCl solution based on the assigned treatments. Then the pigs were slaughtered at 4 h and 24 h after LPS or saline injection, and the liver samples were collected. Results: At 24 h after LPS challenge, dietary supplementation with 0.5% Asn increased ATP concentration (quadratic, p<0.05), and had a tendency to increase adenylate energy charges and reduce AMP/ATP ratio (quadratic, p<0.1) in liver. In addition, Asn increased the liver mRNA expression of pyruvate kinase, pyruvate dehydrogenase, citrate synthase, and isocitrate dehydrogenase ${\beta}$ (linear, p<0.05; quadratic, p<0.05), and had a tendency to increase the mRNA expression of hexokinase 2 (linear, p<0.1). Moreover, Asn increased liver phosphorylated AMP-activated protein kinase (pAMPK)/total AMP-activated protein kinase (tAMPK) ratio (linear, p<0.05; quadratic, p<0.05). However, at 4 h after LPS challenge, Asn supplementation had no effect on these parameters. Conclusion: The present study indicated that Asn could improve the energy metabolism in injured liver at the late stage of LPS challenge.

• Safety and Health at Work
• /
• v.9 no.4
• /
• pp.473-478
• /
• 2018

Background: Multiple Chemical Sensitivity (MCS) is an acquired disease which etiology remains unknown. It is characterized by the development of sensitivity to certain chemical products. Most of the hypotheses formulated to explain the syndrome associate it to a previous exposition to some kind of volatile chemical. University researchers in chemical laboratories suffer a phenomenon of multi-exposition to chemical agents at low concentration during long periods of time although in an irregular form. Many of these chemical agents have similar properties to those suspicious of causing MCS. This article studies the prevalence of MCS in laboratory researchers. Methods: The study group is university researchers in chemical laboratories. The control group was obtained from administrative personnel who work in the same universities and therefore, are not exposed to chemical products from the laboratories, but have the same exposition to the rest of environmental polluting agents from the area and from the buildings of the university. In this study, it is used the Quick Environmental Exposure and Sensitivity Inventory (QEESI) (sensitivity of 92%/specificity of 95%). Results: The results showed that the prevalence of MCS for the university researchers is not related to exposition by inhalation to multiple chemical agents, at low concentration. Conclusions: The results disagree with one of the main etiological hypotheses of MCS, which is based on the existence of hypersensitive people, who presents a response after prolonged expositions to very low concentrations during a long period of time.

• Korean Journal of Hazardous Materials
• /
• v.6 no.2
• /
• pp.87-94
• /
• 2018

The study is aimed to analyze the MSDS awareness as per the properties, including general characteristics, of laboratory workers in university. It conducted the self-administered survey on the subject of 780 laboratory workers engaging in research activities in three university from February to May, 2017. Among them, it analyzed 686 cases except 94 of them, lacking content. As a result, education experience of MSDS, necessity of education, usage experience of MSDS, installation, comprehension, and accessibility showed a strategically significant difference in the recognition of MSDS. According to the categorical importance of MSDS, "the first aid measures" directly related to life was most significantly considered. It is estimated that it will contribute to prevention of safety accident by strengthening education on MSDS and increasing the level of awareness for laboratory workers.