• The Journal of Korean Medicine
• /
• v.44 no.3
• /
• pp.29-38
• /
• 2023

Objectives: This study aimed to investigate the acute oral toxicity of 77 herbal formulas and performed in male and female Sprague-Dawley (SD) rats as per the guidelines mentioned in Ministry of Food and Drug Safety. Methods: Each sex of SD rat were administered a single dose (2000 or 5000 mg/kg) of 77 herbal formulas via oral gavage; the control group received vehicle only. After administration, the mortality, clinical signs, gross findings, and body weight were followed up for 15 days. Results: After administration of 77 herbal formulas, mortality, clinical signs, body weight changes, and gross findings related to the test substances were not observed in both male and female groups. Conclusion: Our results demonstrate the single-dose oral administration of 77 herbal formulas produced no mortality indicating the approximate lethal dose is greater than 2000 or 5000 mg/kg body weight.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.12 no.2
• /
• pp.236-247
• /
• 2009

In Korea, the driving system restriction criteria is strictly applied(gross weight 400kN, axial load 100kN). Especially after the Seoungsu Bridge accident, safety factor has been strictly applied. The Safety factor is applied to the cumulative results for each steps like design, construction, maintenance of the Bridge. Because of it, the bridge is undervalued compared to its capacity. So, this generates loss for both private and military sector(eg. logistical delays, structural damage, etc.). But analyzing data from many existing researches we have confirmed that the military heavy vehicle may pass through the first class bridges. In consequence, this study have focused on determining whether HETS vehicles can pass over the first class bridge, without safety issues, using MIDAS structural analysis program. The results have confirmed that the military heavy vehicle may pass over the bridge.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.21 no.6
• /
• pp.790-798
• /
• 2018

Discrete noise signals from a small scale tactical unmanned aerial vehicle(UAV) propeller were predicted numerically using time domain approach. Two-bladed 29 inch propeller in diameter and 150 kgf in gross weight were used for main parameters of the UAV based on the actual size of the similar scale vehicle. Panel method and Farassat formula A1 were adopted for aerodynamic and aeroacoustic analysis respectively. Time domain signals of both thickness and loading noises were transformed into frequency domain to analyze the discrete noise characteristics. Directivity pattern in a plane perpendicular to the rotating disc plane and attenuation of noise intensity according to double distance were also presented.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.18 no.4
• /
• pp.348-354
• /
• 2009

In order to reduce the risk of roll over crash, one of the greatest risk events, National Highway Traffic Safety Administration(NHTSA) issued Notice of Proposed Rulemaking(NPRM) enhancing the safety standard on roof crush resistance, FMVSS No. 216 and changing some part of the test procedure. According to this NPRM, the boundary Gross Vehicle Weight Rating(GVWR) of the vehicles applied by this standard is extended from 2,722kg(6000 lb) to 4,536 kg(10000 lb) and the applied test force is increased from 1.5 times to 2.5 times of Unloaded Vehicle Weight (UVW). Also the current limit on the amount of roof crush, 127mm(5 inch), is replaced with a new requirement of maintaining enough headroom without touching the head of a seated 50% male dummy. In this paper, we carried out the rollover crash test on some domestic cars and investigated their safety due to the KMVSS No. 92 and the enhanced safety standard, FMVSS No. 216, respectively. The result shows that most of them can satisfy the new standards but further tests will be necessary, especially for heavier cars.

• International Journal of Highway Engineering
• /
• v.12 no.3
• /
• pp.17-26
• /
• 2010

Maintenance of the roads and bridges is a major issue for all road administrators around the world, and various initiatives are being implemented in each region for the purpose of controlling the ever increasing road maintenance cost while ensuring the safety of the vehicles driving. Efforts for such initiatives have also been made in Asia and initiatives for managing heavy-weight vehicles have recently gained momentum in Korea and Japan. We have developed a technology for unevenly installing bar-shaped sensors (piezo quartz sensors) to enable dynamic axle load measurement at a highly accurate level, and have estimated our measurement accuracy of axle load/gross weight, etc. on an actual road. The measurement accuracy of the axle load/gross weight varies significantly depending on the number of sensors installed. In our implementation, the target accuracy was set to below ${\pm}5%$ for gross weight measurement so that automatic regulation can be applied. We have achieved our target by installing 8-point measurement system. However, to have this technology widely accepted, it was necessary to reduce the system size so that it can be easily implemented. Therefore, we have estimated the relationship between the measurement accuracy and the system size (number of measurement points), and have come up with the proposal of 3-point measurement as an optimum number of measurement points, and have estimated its performance on an actual road. Additionally, we evaluated the relationship between the measurement accuracy and vehicle velocity.

• Structural Engineering and Mechanics
• /
• v.47 no.5
• /
• pp.643-660
• /
• 2013

In the present work, the capacity ratings of steel truss bridges have been carried out incorporating dynamic effect of moving vehicles and its accumulating effect as fatigue. Further, corrosion in the steel members has been taken into account to examine the rating factor. Dynamic effect has been considered in the rating procedure making use of impact factors obtained from simulation studies as well as from codal guidelines. A steel truss bridge has been considered to illustrate the approach. Two levels of capacity ratings- the upper load level capacity rating (called operating rating) and the lower load level capacity rating (called inventory rating) were found out using Load and Resistance Factor Design (LRFD) method and a proposal has been made which incorporates fatigue in the rating formula. Random nature of corrosion on the steel member has been taken into account in the rating by considering reduced member strength. Partial safety factor for each truss member has been obtained from the fatigue reliability index considering random variables on the fatigue parameters, traffic growth rate and accumulated number of stress cycle using appropriate probability density function. The bridge has been modeled using Finite Element software. Regressions of rating factor versus vehicle gross weight have been obtained. Results show that rating factor decreases when the impact factor other than those in the codal provisions are considered. The consideration of fatigue and member corrosion gives a lower value of rating factor compared to those when both the effects are ignored. In addition to this, the study reveals that rating factor decreases when the vehicle gross weight is increased.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.19 no.6
• /
• pp.10-18
• /
• 2015

Performance requirement analysis and weight estimation of a reusable launch vehicle with a rocket-based air-breathing engine(RBCC : Rocket Based Combined Cycle) were performed. Performance model for an RBCC engine was developed and integrated with flight trajectory model. The integrated engine-trajectory model was validated by comparing the results with those from previous research reference. Based on the new engine-trajectory model and previous research results, engine performance requirements were derived for an reusable launching vehicle with gross take-off weight of 15 tones. Dependence of the propellant amount requirement on the mode transition Mach number of the engine was also analyzed.

• IE interfaces
• /
• v.17 no.2
• /
• pp.142-148
• /
• 2004

The objective of bridge construction cost allocation is to distribute in a fair and rational manner the bridge construction costs among those vehicles using the bridge. In most bridge construction cost allocation studies, bridge construction costs are mainly distributed according to traffic load(gross vehicle weight), without any consideration of bridge capacity requirements(the number of lanes). In this paper, a bridge cost allocation method for considering both traffic capacity and traffic loads is developed. The proposed method is based on cooperative game theory, particularly two concepts known as the Aumann-Shapley (A-S) value and Shapley value. This method can help to analyze the impact of traffic capacity costs. By applying the proposed method to an example, traffic capacity cost is found to be high so that traffic capacity should be considered to allocate the bridge construction costs to vehicle classes in a more equitable manner.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.12
• /
• pp.1095-1102
• /
• 2016

This paper presents the results of the design, fabrication and tether test for a gross weight 20 kg tilt-duct VTOL aerial robot. The tilt-duct vehicle, a tri-ducts air-vehicle, which composed of two main tilt ducts for thrust and an aft-fan for pitch attitude control, has been developed as an aerial platform. The research on the air vehicle has been focused on the hover characteristics and controllability to improve the thrust and stability. The tether test for measuring various performance of vehicle and evaluating controllability have been carried out to figure out effects of modified main-prop linkage, actuator, duct configuration and control surfaces.

• Korean Journal of Oriental Medicine
• /
• v.16 no.2
• /
• pp.143-157
• /
• 2010

Objectives : The objective of this study was to access the effect of Artemisiae capillaris herba Extracts on the organogenetic reproductive toxicity of New Zealand White rabbits when administered by oral gavage. Methods : Gestational New Zealand White rabbits were dosed from 6 days of gestation to 18 days of gestation. It was conducted in accordance with the recommendations of the KFDA Guideline for Detection of Toxicity to Reproduction for Medicinal Products. In addition, serum AST, ALT, LDH and ALP levels were detected with their necropsy and histopathological observation Results: No significant changes of body weights, gains and food consumption were demonstrated in all dosed groups compared to those of vehicle control group except for 2,000mg/kg-dosing group, which showed significantly increase of body weight compared to that of vehicle control group. Normal gross findings were demonstrated in all tested groups. No significant changes of number of corpora lutea, implantation, implantation rate, number of fetal death, loss rate of post-implantation, number of live youngs at C-section, survival rate of post-implantation, number of male live youngs at C-section, number of female live youngs, sex ratio of live young, external anomalies of live youngs and body weight of live youngs were demonstrated in all dosed groups compared to those of vehicle control group. Although some visceral variations such as thymic reminant in the neck, dilation of renal pelvis, dilated ureter and malpositioned left common carotid artery, no significant changes were demonstrated in all dosed groups compared to that of vehicle control group. Some malformations and variation were demonstrated with retardations. However, no significant changes were demonstrated in all dosed groups compared to that of vehicle control group. In addition, similar ossification numbers were detected in sternebrae, metacarpals, metatarsals, phalanges, cervical vertebrae, and sacral and caudal vertebrae. No Artemisiae capillaris herba Extracts treatment-related changes of serum AST, ALT, LDH and ALP levels were demonstrated in all dosed levels in this study. Conclusions : We could conclude that oral administration of Artemisiae capillaris herba Extracts hasn't an influence on the organogenetic reproductive toxicity.