The purpose of this study was to investigate the effects of visual cue deprivation during sideways
treadmill training in individuals with stroke. Twenty-eight stroke patients were divided into two groups, and each group participated in a sideways treadmill training session for 20 minutes, three times per week for 4 weeks. The eyes close group (15 subjects) performed this treadmill training with visual cue deprivation, while the eyes open group (13 subjects) performed it without visual cue deprivation. Gait function was measured in both groups before and after the training sessions with the Biodex Gait Trainer 2, which determined walking speed, distance, step length, and time on each foot. Balance was measured before and after each training period in both groups using the Five-Times Sit-to-Stand Test (FTSST), the Timed Up and Go test (TUG), and the seven-item Berg Balance Scale-3P (7-item BBS-3P). The eyes close group showed significantly improved gait function, walking speed, distance, step length, and time on each foot after training (p<.05). The eyes close group showed improved balance ability, FTSST, TUG, and 7-item BBS-3P test after training (p<.05). The findings indicated that sideways treadmill training with visual cue deprivation positively affects gait ability of stroke patients. Therefore, sideways treadmill training with visual cue deprivation may be useful for the recovery of gait ability of stroke patients.
PURPOSES : The objective of this study is to evaluate the environmental resistance of bio-polymer concrete for use of pavement materials developed for reducing the carbon-dioxide. METHODS : The compression, tension, and bending strength tests were conducted on the bio-polymer concrete specimens with and without environmental conditioning. The specimens were conditioned using the freezing-thaw and accelerated weathering process for long period of time. To assess the resistance against chloride, the chloride ion penetration resistance tests were carried out on the bio-polymer concrete specimens. RESULTS : Test results show that the maximum difference in strength between specimens with and without conditioning is about 2.6MPa indicating that the effect of environmental conditioning on specimen strength is negligible. Based on the chloride ion penetration resistance test, the penetration quantity of electric charge of the specimens is zero and there is no ion penetration within the bio-polymer concrete. CONCLUSIONS : It is found from this study that there is slight change in strength of bio-polymer concretes before and after environmental conditioning process and no chloride ion penetration observed in these specimens. Therefore, the developed bio-polymer concretes can be applied effectively as pavement materials due to the small change of physical properties with environment change.
전 세계적으로 산업의 고도화로 인하여 환경오염이 급속도로 진행되고 있으며, CO2 발생의 증가로 지 구 온난화 현상이 급속도로 진행되고 있다. 기존의 일반 아스팔트포장은 약 160℃의 고온에서 생산 및 시공되기 때문에 CO2가 크게 발생되며, 시멘트포장 또한 시멘트 생산 시 CO2가 발생되고 있다. 최근 강상판 장대교량(케이블교)의 건설이 증가하고 있으며, 사하중을 절감하기 위한 박층 폴리머 콘크리트가 개발되고 있다. 그러나 폴리머 수지도 석유계 재료로 생산되기 때문에 CO2가 발생되며 석유자원 의 고갈로 인한 폴리머 수지의 가격 상승 등이 문제점으로 부각되고 있다. 이러한 문제점의 대안으로 식물성 수지를 사용한 바이오 폴리머 수지를 개발하는 연구가 지속적으로 수행되고 있다. 그러나 식물성 재 료를 사용하게 되면 기존 석유계 수지에 비하여 강도 및 환경 영향에 대한 물리적 특성이 감소하는 문제 가 발생하여 차량하중의 영향이 작은 주차장, 보도, 자전거 도로 등에 적용되고 있는 실정이다. 본 연구에서는 기존 석유계수지의 약 30~50%를 식물성 재료로 대체한 도로포장용 바이오 폴리머 수지를 개발하고자 한다. 식물성 재료는 콩유(Soybean Oil), 피마자유(Castor Oil), 야자수유(Palm Oil) 등 그 종류가 다양하지만 폴리올(Polyol)공정을 거치지 않고 생산이 가능한 피마자유를 이용하여 생산비용을 절감하였으며, 환경 영향 저항성과 관련된 시험을 수행하여 도로포장에 대한 적용성을 평가하였다. 식물 성 재료가 약 30% 첨가된 수지(906-3)와 50% 첨가된 수지(2I)를 대상으로 무처리 상태의 강도와 처리 후(동결융해, 자외선)의 강도를 측정하여 비교·평가하고 염화물에 대한 저항성을 시험하였다. 그 결과 기 존 석유계 폴리머 수지에 식물성 재료를 50% 대체하여도 강도변화가 미미한 결과를 도출하여 바이오 폴리머 수지를 도로포장에 적용하여도 문제가 없음을 확인하였다.
PURPOSES : The objectives of this study are to develop the eco-friendly pavement material using polyurethane binder and evaluate mechanical properties of the developed binder and concrete. METHODS : The bending beam test was conducted to select the sample candidates of polyurethane binder based on the bending strength. The characteristics of viscosity, curing time, and temperature change of sample binder was examined on different temperature conditions. The mechanical properties of polyurethane binder was estimated using the dynamic modulus testing. The indirect tensile strength test was conducted on polyurethane binder concrete with different gradation and binder content for evaluating the mechanical properties of concretes. RESULTS : Based on the beading beam test, four different binder samples were prepared for estimate the mechanical properties. The viscosity of polyurethane binder tends to increase with increase of liquid temperature and the hardening phenomenon begins 10 to 15 minutes at room temperature after mixing the resin and hardener. It is observed that the dynamic modulus of binder increases as loading frequency increases and change of modulus is found to be the highest in the PU-2I binder type. The PU-2I binder concretes shows the largest value of indirect tensile strength and indirect tensile energy. CONCLUSIONS : The use of polyurethane binder as pavement materials is capable of increasing the pavement performance and reducing the detrimental environmental effect during the highway construction.
PURPOSES : The objective of this study is to evaluate the effect of physical characteristics of emulsion asphalt and aggregate on performance of chip seal pavements. METHODS : In order to evaluate the performance of chip seal materials, the sweep tests and Vialit Plate Shock tests were conducted on the mixtures with five emulsion asphalt binders and three aggregate types. The sweep tests was intended to investigate the change of bonding properties between emulsion asphalt and aggregate with curing time. The Vialit Plate Shock test was used to evaluate the bonding properties of chip seal materials at low temperatures. RESULTS : Results from sweep tests showed that polymer modified emulsion asphalt can reduce the curing time by 1.5 hour comparing with typical emulsion asphalt. It is also found that the Flakiness Index of aggregates and absorption rate of binder are the major factors affecting the bonding properties of chip seal materials. The Vialit Plate Shock test results showed that the average aggregate loss of CRS-2 is ten times higher than CRS-2P No.2 indicating that the use of polymer additives in emulsion asphalt can improve the performance of chip seal materials in low temperature region. CONCLUSIONS : The use of polymer in emulsion asphalt can decrease the curing time of chip seal materials and increase the bonding properties between aggregates and asphalt binder. It is also concluded that the lower Flakiness Index and absorption rate of aggregates can improve the performance of chip seal pavement.
PURPOSES : The objective of this study is to evaluate the mechanical characteristics of castor oil based bio-polymer concrete for use of ultra thin overlays. METHODS : To evaluate the mechanical properties of bio-polymer concrete, the various laboratory tests including compressive, tensile, and flexural strength, and elongation tests were conducted on bio-polymer concrete specimens in this study. The mechanical characteristics of bio-polymer concretes were examined by changing the content of hardener and polymer binder to determine the optimum content for ultra-thin overlays. The bio-polymer concrete developed in this study was used for field trial test of the ultra-thin bridge deck pavement for verifying the workability and monitoring the long-term performance of materials. RESULTS : Test results showed that tensile and the flexural strength of bio-polymer concretes increase and the elongation of bio-polymer concrete decreases with increase of binder content. A field adhesive strength tests conducted on bridge deck pavement indicates the bio-polymer concrete has more than 2MPa of adhesive strength satisfy with the design criteria. CONCLUSIONS : The bio-polymer concrete with more than 20% content of castor oil was developed for ultra-thin overlays in this study. It is found from this study that the 35% of hardener content is most appropriate for maintaining the strength characteristics and flexibility.
PURPOSES: The objective of this study is to analyze and evaluate the behavior of orthotropic steel bridge deck pavement using three-dimensional finite element analysis and full-scale wheel load testing. METHODS: Since the layer thickness and material properties used in the bridge deck pavement are different from its condition, it is very difficult to measure and access the behavior of bridge deck pavement in the field. To solve this problem, the full-scale wheel load testing was conducted on the PSMA/Mastic bridge deck pavement and the deflection of bridge deck and horizontal tensile strain on top of pavement were measured under the loading condition. Three-dimensional finite element analysis was conducted to predict the behavior of bridge deck pavement and the predicted deflection and tensile strain values are compared with measured values from the wheel loading testing. RESULTS: Test results showed that the predicted deflections are 10% lower than measured ones and the error between predicted and measured horizontal tensile strain values is less than 2% in the critical location. CONCLUSIONS: The fact indicates that the proposed the analysis is found to be accurate for estimating the behavior of bridge deck pavements.
PURPOSES: The purpose of this study is to evaluate physical properties, durability, fatigue resistance, and long-term performance of poly-urethane concrete (PU) which can be possible application of thin layer on long-span orthotropic steel bridge and to check structural stability of bridge structure. METHODS : Various tests of physical properties, such as flexural strength, tensile strength, bond strength and coefficient of thermal expansion tests were conducted for physical property evaluation using two types of poly urethane concrete which have different curing time. Freezing and thawing test, accelerated weathering test and chloride ion penetration test were performed to evaluate the effect of exposed to marine environment. Beam fatigue test and small scale accelerated pavement test were performed to assess the resistance of PU against fatigue damage and long-term performance. Structural analysis were conducted to figure out structural stability of bridge structure and thin bridge deck pavement system. RESULTS: The property tests results showed that similar results were observed overall however the flexural strength of PUa was higher than those of PUb. It was also found that PU materials showed durability at marine environment. Beam fatigue test results showed that the resistances of the PUa against fatigue damage were two times higher than those of the PUb. It was found form small scale accelerated pavement test to evaluate long-term performance that there is no distress observed after 800,000 load applications. Structural analysis to figure out structural stability of bridge structure and thin bridge deck pavement system indicated that bridge structures were needed to increase thickness of steel deck plate or to improve longitudinal rib shape. CONCLUSIONS: It has been known that the use of PU can be positively considered to thin layer on long-span orthotropic steel bridge in terms of properties considered marine environment, resistance of fatigue damage and long-term performance.
본 연구에서는 무격막식 전기분해 처리된 해수를 산화제로하는 NO 산화반응의 특성에 대해 실험적으로 살펴보았다. 폐순환 정전류 전기분해 시스템을 통해전해 시간이 길어질수록 전해수의 유효 염소농도와 온도, 염소산 이온의 비율이 증가함을 확인하였다. 전해수가 채워진 버블링 반응기에서 전해수의 유효염소농도와 온도에 비례하여 NO2로 산화되는 NO의 양이 증가하였다. 또한 산화되어 생성된 NO2는 전해수에 용해되어 HNO3- 이온으로 존재함을 확인하였다.
It could be debated that the owners were indemnified from the charterers even in respect of the loss of deck cargo caused by the negligence on the part of the owners' servants by a clause 13(b) of NYPE(1993) form, where NYPE(1993) incorporated the Hague/Visby Rules by a paramount clause and did not contained an on deck statement to state or identify what or how much deck cargo was being carried, however the relevant bills of lading all had such statement. The socol 3 of U.K. is a very helpful decision on (1) an on deck statement in bill of lading was sufficient to exclude application of the Hague/Visby Rules to the carriage of deck cargo, as a result, the clause 13(b) should not be null and void by the clause 3(8) of the Hague/Visby Rules (3) the clause 13(b) could not protect the owners from the loss and/or liability caused by negligence and/or breach of the obligation of seaworthiness on the part of the owners, their servants and agents. Therefore, the purpose of this study is to critically analyze the decision in the socol 3, and provide the decision's practical implications in order to prevent legal disputes as to the on deck carriage between the owners and the charterters.
2011년 5월 강원도 평창군에 위치한 곰취 재배 포장에 메뚜기류의 피해가 심하게 발생하여 이에 대한 분류동정 및 피해상황, 기주범위 등을 조사하였다. 곰취를 가해하고 있는 메뚜기 약충을 채집, 사육하여 우화 후 분류동정한 결과, 긴날개밑들이메뚜기(Ognevia longipennis Shiraki)로 확인되었다. 포장에서의 피해상황은 노지재배의 경우 가해엽율이 22.5~50.0%, 비가림 시설재배에서는 3.0~12.5%로 나타났으며, 특히 산림과 인접한 지역에서 피해가 심하였다. 긴날개밑들이메뚜기는 곰취 외에도 참취, 고려엉컹퀴, 눈개승마 등의 산채류를 가해하는 것으로 조사되었으며 작물별 피해정도는 곰취>고려엉컹퀴>참취>눈개승마 순 이었다. 또한 조사지역 외에도 평창군 봉평면, 양구군 양구읍 등의 산채 재배 포장에서도 발생이 확인되었고, 7월 까지 피해가 지속되는 것으로 조사되었다.
2011년 5월 강원도 평창군에 위치한 곰취 재배 포장에 메뚜기류의 피해가 심하게 발생하여 이에 대한 분류동정 및 피해상황, 기주범위 등을 조사하였다. 곰취를 가해하고 있는 메뚜기 약충을 채집, 사육하여 우화 후 분류동정한 결과, 긴날개밑들이메뚜기(Ognevia longipennis Shiraki)로 확인되었다. 포장에서의 피해상황은 노지재배의 경우 가해엽율이 22.5~50.0%, 비가림 시설재배에서는 3.0~12.5%로 나타났으며, 특히 산림과 인접한 지역에서 피해가 심하였다. 긴날개밑들이메뚜기는 곰취 외에도 참취, 고려엉컹퀴, 눈개승마 등의 산채류를 가해하는 것으로 조사되었으며 작물별 피해정도는 곰취>고려엉컹퀴>참취>눈개승마 순 이었다. 또한 조사지역 외에도 평창군 봉평면, 양구군 양구읍 등의 산채 재배 포장에서도 발생이 확인되었고, 7월 까지 피해가 지속되는 것으로 조사되었다.
We tried to establish the history of outbreaks and control methods of ‘hwangchung’ in Joseon Dynasty, uncovering the biological reality of the ‘hwangchung’ (called hwang or bihwang) analyzed through the Database program on ‘the Annals of the Joseon Dynasty’ and ‘the Enrollment of Haegoeje’, two of the finest examples of classical historical records. The total number of articles on the outbreak of the hwangchung is 261 in the Annals of the Joseon Dynasty and 65 in the Enrollment of Haegoeje. There were four peaks by hwangchung throughout the Joseon Era. Among them, the periods of King Taejo to King Sejong had the highest incidence. By comparing the number of records of the hwangchung from the Annals of the Joseon Dynasty with that in the Enrollment of Haegoeje during the same period, results show the former was less than the latter, 35 vs 65. However, both records were relatively inconsistent with each other. Insect pests in forests as well as in agriculture were included in the biological identities of the hwangchung in the Joseon Dynasty periods, which is in accordance with those of Saigo’s. The taxonomic identity could be confirmed in only 25 cases (9.5%) among the articles on hwangchung. It largely coincided with Paik"s opinion: 11 in armyworm, nine in moth larva, one in rice stem borer, two in migratory locust, one in planthopper and one in rice-plant weevil. Therefore, it is not reasonable to regard hwangchung as a migratory locust or grasshopper only. The number of reports on the occurrence of hwangchung in the Annals of the Joseon Dynasty was 173 (66% of the total) and 47% of them were just simple reports, which means the report itself on the appearance of hwangchung was very significant. The reports on controlling insect pests were of low frequency, in 20% (34 cases) of the total reports, capturing insect pests or holding traditional ceremony called ‘Poje’. Among them, only one case related to the treatment of seeds to prevent the damage by hwangchung was published in the King Sejong period. There were 37 discussions about changes and management of government policies due to disasters by hwangchung. They were mostly about relief or tax cut to the people who suffered damage and about cancellation of recruiting people to military training, constructing castles, and so on. It seems that not only the people but also the king was influenced by the hwangchung. In the case of King Seongjong, he referred to the stress of the prevention measure of locusts in 10 articles. The damage also had an effect on abdication in the reign of King Jeongjong.
As more than 90% of global trade is carried by sea there is little doubt that the safety of the ports at which the world's trading fleet call is of critical concern. The concept of 'safe port' continues to be an area of critical concern for charterers and ship-owners. In light of increased global security and health risks the recognised principles are under security. This paper examines the nature of safe port, and analyses the precedent trend of safe port and its Implication
본 연구는 콘크리트 슬래브 및 포장도로에 덧씌우기 포장으로 개발된 아크릴 폴리머 콘크리트의 물리 역학적 특성을 평가하기 위하여 수행되었다. 점도시험, 흐름시험, 압축강도시험, 휨 강도시험, 인장강도시험, 선 수축시험, 열팽창계수시험 및 온도변화에 대한 부착성 등 다양한 실내 시험을 실시하였다. 본 연구에서 개발된 아크릴 폴리머 콘크리트의 실내시험 결과 ACI에서 제시하는 모든 기준을 만족하는 것으로 평가되었다. 아크릴 폴리머 콘크리트의 공용성을 평가하기 위해 추가적으로 포장가속시험(APT)을 수행하였으나 등가 단축하중을 15,909,939회를 적용하는 동안 심각한 파손을 확인할 수 없었다. 마지막으로 현장 적용성을 평가하기 위하여 열화현상이 진행된 콘크리트 도로에 10mm의 폴리머 콘크리트 덧씌우기를 적용하였다. 현장 적용 후 미끄럼 저항성, 소음 및 평탄성을 측정한 결과 미끄럼 저항성 및 소음도는 상당히 개선되었으나 평탄성 측정치는 다소 증가하였다. 추후 현장에 적용된 아크릴 폴리머 콘크리트의 정기적인 조사를 통하여 장기 공용성 평가를 수행할 예정이다.
우리나라 해충의 역사에서 가장 많이 등장하는 해충명이 황(蝗), 황충(蝗蟲), 또는 비황(飛蝗)이다. 황충은 어떤 특정종의 이름이 아니며, 중국을 비롯한 한자문화권에서 흔히 이주형 풀무치 또는 메뚜기의 총칭으로 흔히 알려져 있다. 하지만, 한반도의 문헌을 비교하여 일찌기 Saigo(1916), Maramatsu(1921), Okamoto(1924)는 군거성 풀무치, 멸구류, 또는 일부 다른 종이 섞여있다는 주장들을 제기한 바 있다. 이에 백(1976과 1977)은 조선왕조실록에서 38건의 황충에 대한 기사를 추출해 분석하여 황충은 멸강나방이 주를 이루고, 일부는 벼멸구이고, 풀무치는 1건만 확인되며 나머지는 종류미상이라 하였다. 하지만 최근에 윤과 문(2003과 2006)은 황충으로 풀무치와 대발생이 가능한 메뚜기류를 중심에 놓고 다른 곤충류의 가능성도 열어둔 바 있다. 이들 주장사이에는 한반도의 황충이란 것이 중국대륙처럼 풀무치를 비롯한 메뚜기류가 중심무리인지 또는 멸강나방 같은 과거에서 현대까지 이어 발생하는 주요 농업해충이 중심 무리인지를 놓고 해석의 차이가 벌어지게 된다. 따라서 우선 조선시대 관료들이 황충을 어떻게 이해했는지 문헌을 통해 고증하고자 한다. 아울러 조선왕조실록 원문DB에서 찾아볼 수 있는 황충 관련기사 229건를 분석하였고, 그 가운데 해석이 가능한 범위에서 현재의 생물학적 실체를 밝히고자 시도하였다. 이를 통해 볼 때, 조선시대의 황충의 실체는 미확인 종이 다수를 차지하였지만, 분석된 기사 중에는 멸강나방 유충을 대표로한 농업해충이 대부분을 차지하고, 진정한 메뚜기류로 볼 수 있는 기록은 2건에 불과하였다. 아울러 문헌 비고를 통해 조선의 황충이란 것은 농업생태계에서 주로 집단적으로 발생하는 해충을 일컫는 용어로 보는 것이 타당할 것으로 판단되었다.