• Elastomers and Composites
• /
• 제36권4호
• /
• pp.225-236
• /
• 2001

2원, 3원 공중합 점착제의 물성을 향상시키기 위해 4인 공중합체를 단량체의 종류와 농도, 개시제의 종류와 농도, 반응온도와 반응시간, 용매의 종류 및 단량체와 용매의 혼합비를 변화시켜 합성하여 점착제의 물성인 점도, 분자량, 전환율, 고형분과 구조분석들을 고찰하였다. 합성한 각 중합체에 내하여 가교제의 종류 및 농도를 변화시켜 점착세의 성능인 점착력. 유지력, 내열성, 내후성, 경시변화를 고찰한 결과, 디음과 같은 결론을 얻었다. 4원 공중합체의 최적 혼합비는 BA/2-EHA/MMA/2-HEMA인 경우, 주단량체인 BA/2-EHA가 80%, 공단량체인 MMA가 15%, 관능성 단량체 2-HEMA가 5%. BA/2-EHA/MMA/AA인 경우, 주단량체인 BA, 2-EHA가 80%, 공단량체인 MMA기 15%, 관능성 단량체 AA가 5%이다. 4원으로 합성한 RA/2-EHA/MMA/2-HEMA의 점착제에 가교제로 이소시아네이트가 적합하였으며, BA/2-EHA/MMA/AA인 경우는 가교제로 멜라민계가 적합하고 점착력의 경시변화는 가교제로 이소시아네이트(PTDI)나 멜라민계 모두 균일하있으며, 내후성 시험후에 표면관찰을 하면 멜라민계는 점착제 잔유물이 남아있어 불안정했고, PTDI는 점착제 잔유물이 전혀 없이 안정성이 우수하였다.

• 한국도로학회논문집
• /
• 제18권6호
• /
• pp.41-50
• /
• 2016

OBJECTIVES : In this study, microstructural components of crumb rubber modified asphalt (CRMA) binder were investigated using environmental scanning electron microscope (ESEM). To clearly understand the elemental composition of the CRMA binder, energy dispersive X-ray spectroscopy (EDX) was employed on the ESEM samples. METHODS : CRMA binders were produced using open blade mixers at $177^{\circ}C$ for 30 min. The binders were artificially aged through a series of accelerated aging processes. Sample preparation was done by making a mold shape on the glass slide. Thereafter, the morphology of the CRMA binder was observed using the ESEM coupled with the EDX. RESULTS : The images captured from the ESEM indicate that the unaged CRMA binder appears to have a single-phase continuous nonuniform structure after the addition of crumb rubber particles, whereas the artificially aged CRMA binder was observed to have two different phases. ESEM coupled with EDX shows detailed internal structure of the modified binders compared to other technologies (i.e., optical microscopy, atomic force microscopy, and conventional scanning electron microscope). CONCLUSIONS : The captured images resemble the internal structures such as the viscous properties of the unaged CRMA binder and the interaction between the rubber particles and the base binder at aged condition. ESEM is a powerful instrument and with the introduction of EDX, it provided more details of the network microstructure of the asphalt binder. ESEM coupled with EDX is recommended for use in future investigation of microstructure of asphalt binders.

• 한국실내디자인학회논문집
• /
• 제20권2호
• /
• pp.85-93
• /
• 2011

The Japanese housing market has implemented management and operation systems of community service ahead of the Korean market. This paper examines case studies of Japanese community services by reviewing related studies, studying homepages, and conducting in-depth interviews with management staff. The goal of this study is to find marketing strategies and the proper management practices in preparation for the upcoming low-fertility and aging society. The results of this study are as follows: 1) After Japan's bubble economy burst in 1985, so called that incorporated various community facilities with life services were introduced to the Japanese housing market in order to cope with the diversifying family types and lifestyles. This new trend was also due in part to customers' increasing demands for convenient urban condominiums. 2) In Japan, many developers and construction companies have run the management of community service programs and created new business models in collaboration with other affiliated companies. However, many of these programs have been found even more successful and reliable when the facility management companies collaborate with local service providers instead of relying solely on affiliated companies. 3) The early stage of life services began with "front-desk services", but these have evolved into more upgraded "concierge services" that can provide residents with tailored services and conveniences. Furthermore, some of the service providers have encouraged resident participation in the process of designing and implementing their community services. 4) In Korea, most construction companies and developers are still oriented toward providing hardware such as spaces and facilities in developing their community services. Therefore, companies with high market reputations must seek alternative ways to maintain and enhance their brand values by implementing new approaches in collaboration with both affiliated companies and local service providers. This can be done by finding new notions of managing and operating community services through research and development.

• 대한기계학회논문집B
• /
• 제34권9호
• /
• pp.867-873
• /
• 2010

수냉각 발전기 고정자 권선에서의 냉각수 누수 및 흡습에 의한 절연파괴 손상사례가 국내 및 국외에서 자주 발생되고 있다. 이러한 사고는 막대한 경제적 피해뿐만 아니라 전력의 안정적 공급 측면에서 매우 심각한 계통 사고로 연결될 수 있다. 특히 국내 발전기는 15년 이상 운전되어 열화가 진행된 발전기가 50% 이상이며, 계획예방정비 기간 중에 권선에서의 누설 및 흡습 권선이 종종 발견되고 있다. 기존에는 누수 시험 전 과정인 권선 건조 과정을 무시한 채 누수 시험 결과만으로 권선 누설 여부를 진단하였으나 본 논문에서는 누수 시험을 위한 준비 단계인 진공 건조 시의 권선 내부의 진공도 패턴 분석을 통해 권선 누설 및 흡습 여부를 예측진단할 수 있는 방법을 실험적으로 증명하였다.

• Architectural research
• /
• 제20권3호
• /
• pp.83-92
• /
• 2018

Recently, there has been inter-Korean exchanges are active, in company with an assertive international activity with North Korea and inter-Korean Summits. Thus, there is a growing possibility of Korean reunification. However, when the unification situation occurs, population inflow by North Korean residents will be expected, and it will be necessary to prepare a housing supply strategy. In addition, even if North Koreans are prevented from entering, a plan is necessary to ensure structural safety since most buildings in North Korea are aging and a recent natural disaster occurs frequently. In this research, we will try to present a temporary housing supply strategy and a short-term structural reinforcement plan based on analysis of the standard housing conditions in North Korea. In this research, we represent the analysis result of the existing construction level, supply status and structural performance of North Korea. When we consider the reinforcement period and social costs, a short-term reinforcement plan is recommended rather than the full reinforcement of the aged housing in North Korea. Furthermore, we examine the ways to secure the residential safety of North Koreans through a case study of domestic and overseas temporary residential facilities, until the permanent residential facilities were supplied. According to the analysis, the tent houses were used as a form of relief housing in overseas frequently. However, the tent house is difficult to apply for domestic country with clear seasons due to insulation and heating problems. Therefore, it is appropriate to develop a residential supply strategy as focusing on the temporary housing facilities in assembled or container from, in preparation for the future population inflow.

• 한국농공학회논문집
• /
• 제62권1호
• /
• pp.105-115
• /
• 2020

With the decrease of the agricultural population in Korea, the workers who is vulnerable to labor are increasing in agricultural industry because of aging, feminization of population. They are exposed in poor working environment with higher temperature and concentrations of dust, gas. Higher concentration of harmful gas and dust can cause chronic and acute disease to workers depending on exposure intensity and frequency. In order to improve the working environment in the livestock facilities, It is important to secure monitoring data of the thermal environment and the concentration of harmful gases and fine dust. Multi-point measurement was performed to analyze the regional environmental conditions in the pig rooms. When analyzing the working environment, video monitoring was conducted to analyze the concentration changes of ammonia, hydrogen sulfide and fine dust according to worker movement and work type. Ammonia and hydrogen sulfide monitoring result showed 1.5~2 times higher concentrations than other work when working in the pigs living zone, and 2~4 times higher than other work when working to increase the activity of pigs. In the case of fine dust, the result was 1.3 times higher than the worker's exposure standard in a specific work. The concentrations of gases and dusts from pig farms are not of concern for acute poisoning in normal work, but there is a risk of chronic respiratory disease if they are continuously exposed. Accordingly, there is a need for development of work environment monitoring device tailored to workers and preparation of alternatives.

• 대한물리치료과학회지
• /
• 제21권1호
• /
• pp.37-43
• /
• 2014

Background : The purpose of this study is to verify the type of influence on the skin color according to the photoaging symptoms depending on the degree of external activities among the factors that influence the skin due to UV exposure and to obtain the basic study data on the physical therapy of the skin. Methods : In this study, in order to investigate the type of influence on the skin color according to the photoaging symptoms when the body is exposed to the UV rays having various effects on our body, a study was conducted using questionnaires and skin color measurement tool targeting 20 male college soccer students with many external activities and the senior high school students who has relatively less external activities due to the preparation for college entrance. The skin color was measured and the results were compared. Result : In the test group having relatively higher external activities, while they had less use of the sunscreen, they had more degree of UV exposure, and for the recognition of ultraviolet hazard, more were aware that it was harmful. In addition, in the skin color measurement test conducted targeting the son and the father in order to investigate the association between the skin color and the genetic factors, the experimental group showed a significant difference(p<.05) but the control group did not show any significant difference(p>.05). Conclusion : Based on such study results, the UV exposure time and the use of sunscreen are thought to be an important factor in the skin care.

• 멤브레인
• /
• 제22권5호
• /
• pp.342-351
• /
• 2012

본 연구에서는 PTMSP[poly(1-trimethylsilyl-1-propyne)]의 기체투과에 대한 선택도와 열적 안정성, 시간에 따른 노화현상으로 인한 투과특성의 감소를 개선하기 위해서 PTMSP/PDMS[poly(dimethylsioxane)] graft copolymer에 zeolite를 삽입하여 PTMSP/PDMS-NaY zeolite 복합막과 PTMSP/PDMS-NaA zeolite 복합막을 제조하였다. 물리 화학적 특성을 FT-IR, $^1H$-NMR, TGA, SEM, GPC을 사용하여 조사하였고, $H_2$와 $N_2$ 기체에 대한 투과도와 선택도 성질을 고찰하였다. PTMSP/PDMS-NaY zeolite 복합막과 PTMSP/PDMS-NaA zeolite 복합막 $H_2$와 $N_2$ 투과도는 PTMSP/PDMS graft copolymer 단일막보다 증가하였고, zeolite 함량이 증가함에 따라 증가하였다. 반면에 선택도($H_2/N_2$)는 zeolite 함량이 증가함에 따라 감소하였다. PTMSP/PDMS-NaA zeolite 복합막은 PTMSP/PDMS-NaY zeolite 복합막보다 높은 투과도와 선택도를 보였다.

• Korean Chemical Engineering Research
• /
• 제44권2호
• /
• pp.114-120
• /
• 2006

중금속을 함유하여 환경문제를 야기하고 있는 무기안료를 대체할 환경 친화적 안료 제품을 개발할 목적으로, potassium vanadate와 bismuth nitrate의 수용액으로부터 bismuth vanadate 안료를 제조할 때 공정 변수가 생성되는 안료의 물성에 미치는 영향을 실험적으로 조사하였다. 두 수용액을 각각 일정한 유속으로 서서히 첨가한 후, 반응혼합물의 1차 pH와 2차 pH를 각각 4.5와 7.0~7.5로 하여 침전을 생성시켜 반응혼합물 속에서 3시간 이상 숙성하고, $400^{\circ}C$에서 3시간 이상 소성하면 0.90 이상의 은폐율과 ${\Delta}E^*$값 1.50 이하의 색상을 지닌 bismuth vanadate 안료를 제조할 수 있었다. 반응혼합물 중 Mo의 첨가량이 증가하면 안료의 은폐력이 증가하는 경향을 나타내었으나, 다른 미량 성분들의 영향은 그리 크지 않은 것으로 나타났다.

• Design & Manufacturing
• /
• 제16권4호
• /
• pp.52-59
• /
• 2022

Currently, Korea is an aging society and is expected to become a super-aged society in about four years. X-ray devices are widely used for early diagnosis in hospitals, and many X-ray technologies are being developed. The development of X-ray device technology is important, but it is also important to increase the reliability of the device through accurate data management. Sensor nodes such as temperature, voltage, and current of the diagnosis device may malfunction or transmit inaccurate data due to various causes such as failure or power outage. Therefore, in this study, the temperature, tube voltage, and tube current data related to each sensor and detection circuit of the diagnostic X-ray imaging device were measured and analyzed. Based on QC data, device failure prediction and diagnosis algorithms were designed and performed. The fault diagnosis algorithm can configure a simulator capable of setting user parameter values, displaying sensor output graphs, and displaying signs of sensor abnormalities, and can check the detection results when each sensor is operating normally and when the sensor is abnormal. It is judged that efficient device management and diagnosis is possible because it monitors abnormal data values (temperature, voltage, current) in real time and automatically diagnoses failures by feeding back the abnormal values detected at each stage. Although this algorithm cannot predict all failures related to temperature, voltage, and current of diagnostic X-ray imaging devices, it can detect temperature rise, bouncing values, device physical limits, input/output values, and radiation-related anomalies. exposure. If a value exceeding the maximum variation value of each data occurs, it is judged that it will be possible to check and respond in preparation for device failure. If a device's sensor fails, unexpected accidents may occur, increasing costs and risks, and regular maintenance cannot cope with all errors or failures. Therefore, since real-time maintenance through continuous data monitoring is possible, reliability improvement, maintenance cost reduction, and efficient management of equipment are expected to be possible.