• Journal of Biosystems Engineering
• /
• 제26권5호
• /
• pp.461-468
• /
• 2001

Impact between fruits and other materials is a major cause of product damage in harvesting and handling systems. The oriental pears are more susceptible to bruising than other fruits such as European pears and apples, and are required more careful handling. The interest in the handling of the pears for the processing systems has raised the question of the allowable drop height to which pears can be dropped without causing objectionable damage. Drop tests on pears were conducted using an impact device developed by authors to estimate the allowable drop height without bruising. The impact device was constructed to hold in a selected orientation and to release a fruit by vacuum for dropping on to a force transducer. The drop height was adjustable for zero to 60 cm to achieve the desired distance between the bottom of the fruits and the top of the impact force transducer. The transducer was secured to 150 kg$\sub$f/ concrete block. The transducer signal was sampled every 0.17 ms with a strain gage measurement board in the micro computer where it was digitaly stored for later analysis. The selected sample fruit was Niitaka cultivar of pears which is one of the most promising fruit for export in Korea. The pears were harvested during the 1998 harvest season from an orchard in Daejeon. The sample fruit was selected from two groups which were stored for 3 months and 5 months respectively by the method of current commercial practice. The pears were allowed to stabilize at environmental condition(18$^{\circ}C$, 65% rh) of the experimental room. One hundred fifty six pears were tested from the heights of 5, 7.5. 10 and 12.5 cm while measurement were made of impact peak force, contact time, time to peak force, dwell time, pear diameter and mass. The bioyield strength and modulus of elasticity were measured using UTM immediately after each drop test. The allowable drop height was estimated on the base of bioyield strength of the pears in two ways. One was assumed the peak force during impact test increasing linearly with time, and the other was based on the actual drop test results. The computer program was developed for measuring the impact characteristics of the pears and analyzing the data obtained in the study. The peak force increased while contact times decreased with increasing drop height and contact times of the sample from the hard tissue group. The allowable drop height increased with increasing bioyield strength and contact times, and also varied with Poisson\`s ratio, mass and equilibrium radius of the pears. The allowable drop height calculated by a theoretical method was in the range from 1 to 4 cm, meanwhile, the estimated drop height considering the result of the impact test was in the range from 1 to 6 cm. Since the physical properties of fruits affected significantly the allowable drop height, the physical properties of the fruits should be considered when estimating the allowable drop height.

• 한국운동역학회지
• /
• 제13권3호
• /
• pp.341-354
• /
• 2003

The purpose of this study was to develop the uniaxial force plate system which is measured by the vertical force. The VGRF(vertical ground reaction force) 1.0 was composed of 2 bath digital scales, 2 indicaters, and analyzing software. This system was newly renovated to VGRF 2,0 which are 2 industrial digital scales, 2 adjustable indicators, and enforced analyzing software. Changes of the new system were as follows. First, the height of the plate was 75% lower than before. Second, sensing ability of the load cell was changed from 90 - 0.05kg to 300 - 0.1kg. Third, the speed of data processing was changed from 17 per second to 60 per second. Fourth, analyzing software was enforced to develop and calculate the data. For the test of the system, two different types(bare foot, high-heeled shoes) gait was adopted. highly skilled female walker(23yrs, height 165cm, body mass 46.8kg) participated for the experimental study. During the dynamic performance(gait analysis), the data of each load cell were very similar to the previous studies. Specifically, bare foot walking had less vertical force than high-heeled shoes. Consequently, VGRF 2.0 can sense the general dynamic movements as well as static load conditions.

• 한국광학회지
• /
• 제23권5호
• /
• pp.222-226
• /
• 2012

본 논문에서는, LED 조명의 배광 특성의 조절이 용이한 반사컵 설계 방법을 제안하였다. 먼저 개별 반사컵의 구조와 높이에 대한 방사각의 변화 경향성을 파악하여, 높이에 따른 반사 특성을 확인하였다. 그 결과, 높이에 따라 반사 각도를 조절하여 설계함으로써 배광 분포의 세밀한 조절이 가능했다. 가장 간단한 2단 분할 방식의 경우 방사각의 제어나 균일도 개선을 할 수 있었다.

• 도시과학
• /
• 제10권1호
• /
• pp.1-10
• /
• 2021

The purpose of this study was to evaluate accessibility condition of buildings in a college from manual wheel chair users' perspective in order to suggest improvements, and to develop 3D accessibility maps in order to assist manual wheelchair users' prior planning for the building use. In May 2020, on-site investigation was held to three buildings in Chungbuk National University. Major findings were as follows. (1) There were some building entrances that showed level difference over 2cm without proper ramp with slow slope 1/8 or less. (2) Some rooms were found to have accessibility issues to have floors with height more than 2cm, and/or to have no height-adjustable desks. (3) Although accessible restrooms were in good condition for manual wheelchair users' access and use, it is suggested to install accessible restroom for each gender in each floor for better access. Using the study results, 2-dimensional accessibility maps for each floor were developed in color and grayscale, which were further developed into 3-dimensional accessibility maps for each building.

• 한국해양공학회지
• /
• 제33권1호
• /
• pp.68-75
• /
• 2019

A low-crested structure (LCS) is an excellent feature not only because it provides shore protection but also because it is fully submerged. However, in order to properly control waves, it is necessary to maintain a certain range of crest height and width in consideration of the wave dimensions at the installation area. According to previous studies, an LCS has some wave breaking effect when the crest width is more than a fourth of the incident wavelength and the crest depth is less than a third of the incident wave height. In other words, if the crest width of the LCS is small or the crest depth is large, it cannot control the wave. Therefore, when an LCS is installed in a large sea area with a great tidal range in consideration of the landscape, waves cannot be blocked at high tide. In this study, the hydraulic performances of a typical trapezoidal LCS with a constant crest height and a low-crested structure with an adjustable crest height, which was called a tide-adapting low-crested structure (TA-LCS) in this study, were compared and evaluated under various wave conditions through hydraulic experiments. It was found that the wave transmission coefficients of the TA-LCS at high tide were lower than the values for the typical LCS based on empirical formulas. In addition, the hydraulic performances of the TA-LCS for wave reflection control were 12.9?30.4% lower than that of the typical LCS. Therefore, the TA-LCS is expected to be highly effective in controlling the energy of incoming waves during high tide even in a macro-tidal area.

• 문화기술의 융합
• /
• 제9권6호
• /
• pp.429-434
• /
• 2023

주방 상부장은 주방 도구들을 수납하기 위한 필수적인 가구이지만, 높은 위치에 설치 및 고정되어 있어 상부장의 2층 또는 3층처럼 높은 곳에는 사람의 손이 접근하기 어려운 단점이 있다. 따라서 본 논문에서는 기존 상부장의 기능을 유지하면서 사용자가 물건을 손쉽게 꺼내거나 보관할 수 있도록 높이 조절 기능이 추가된 상부장 구조를 제안한다. 사용자 편리와 안전을 위해 상부장 전체가 아닌 개별 층이 하강하도록 하였으며 선택한 층이 한 번의 동작으로 사용하기 편리한 높이까지 내려올 수 있도록 적절한 복합 링크기구를 설계하였다. 또한, 하강 과정에서 층이 기울어지거나 층간 간섭을 방지할 수 있는 최적의 하강 경로를 설정하였으며 이를 구현하기 위해 적절한 링크 길이와 조인트 위치 및 구속조건을 선정하였다. 보관된 물건들의 하중을 지탱할 수 있도록 FEA 해석을 통해 기구 장치에 대한 안정성을 검증하였으며 실제 제작을 통해 높이 조절 상부장의 정상 작동 여부를 확인하였다.

• 한국실내디자인학회논문집
• /
• 제16호
• /
• pp.49-58
• /
• 1998

This paper proposes a way to design a multi-purpose hall which can serve as a culture and art space for college students and which can also accommodate college students' behaviour characteristics. The major claims made in this paper are as follows. First the hall should be located where it is easily accessible from major and minor campus facilities. Second friendliness between inside and outside of the hall should be established by providing a Gray Zone such as floor or a yard. Third lobby should have a enough space for the entrance and exit of the hall and for rest and refreshments. Fourth in addition to a fixed stage height-adjustable stage and booth should be provided in order to use the hall space for different use. Fifth in the color aspect high value and low chroma should be used to create tender and friendly atmospher and in the shape aspect a durable natural and functional design should be considered in order to create a modern atmosphere.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2009년도 추계학술대회 논문집
• /
• pp.241-244
• /
• 2009

This paper deals with a usefulness verification of stretch forming process using flexible die. The stretch forming method is widely used in aircraft and high-speed train industries for manufacturing of skin structure, which is made of sheet metal. A great number of solid dies are originally used and developed for specific shapes with respect to different curvature radii of the skin structures. Accordingly, flexible stretch forming process is proposed in this study. It replaces the conventional solid dies with a set of height adjustable discrete punches. A usefulness of the flexible die is verified through extensive numerical simulations of the stretch forming process for simply curved sheet plate. The elastic recovery is considered and formability evaluations are conducted through a comparison of symmetry plane configurations.

• 경영과정보연구
• /
• 제17권
• /
• pp.67-81
• /
• 2005

Harbor function has been changed into physical distribution position harbor system for providing most suitable physical distribution service with comprehensive rationalization of international physical distribution over simple loading unloading, and change function by far. Thus, to change our country into advanced economy, the factor of growth obstacles was to be eliminated, or it is so important that the physical distribution base establishment enlarges to improve potential productivity. That is, self effort is needed for physical distribution competition system, adjustable arrangement of physical distribution area, the establishment of comprehensive informations system, physical distribution rationalization. Also, to enforce harbor productivity, harbor should be developed systemically to able to function of comprehensive harbor for enlargement of harbor establishment, the device of advanced harbor function height, the linkage between and city program, harbor operation or investment system provement, harbor technique or international cooperation advancement.

• Membrane and Water Treatment
• /
• 제8권5호
• /
• pp.423-435
• /
• 2017

Settling Basins are one of the most important and popular methods for removal of suspended sediments irrigation and drainage networks or power canals taking off from an alluvial river and wastewater treatment plant. Improving the performance and so increasing sediment removal efficiency of settling basins by an alternative method is necessary. In the present work, the effect of baffle and its angle of attack with the flow (${\theta}$) on the sediment removal efficiency is investigated by conducting a series of experiments on a straight canal with 8 m length, 0.3 m width and 0.5 m height and 3 m length of basin equipped with an adjustable glass baffle. A numerical analysis has been carried out using ANSYS Fluent 3D software (a general purpose computational fluid dynamics simulation tool) for three Froude numbers from the experiments. The numerical and experimental results were found to match reasonably well.