• Title/Summary/Keyword: barrier wall

Search Result 166, Processing Time 0.024 seconds

The Effect of Domain Wall on Defect Energetics in Ferroelectric LiNbO3 from Density Functional Theory Calculations

  • Lee, Donghwa
    • Journal of the Korean Ceramic Society
    • /
    • v.53 no.3
    • /
    • pp.312-316
    • /
    • 2016
  • The energetics of defects in the presence of domain walls in $LiNbO_3$ are characterized using density-functional theory calculations. Domain walls show stronger interactions with antisite defects than with interstitial defects or vacancies. As a result, antisite defects act as a strong pinning center for the domain wall in $LiNbO_3$. Analysis of migration behavior of the antisite defects across the domain wall shows that the migration barrier of the antisite defects is significantly high, such that the migration of antisite defects across the domain wall is energetically not preferable. However, further study on excess electrons shows that the migration barrier of antisite defects can be lowered by changing the charge states of the antisite defects. So, excess electrons can enhance the migration of antisite defects and thus facilitate domain wall movement by weakening the pinning effect.

A Study on The Improvement Effects of Road Traffic Noise by The Noise Barrier Facilities Using a Noise Map Simulation (소음지도를 활용한 방음시설별 도로교통소음 개선효과에 관한 연구)

  • Jeong, Jea-Hun;Park, Jin-Ho;Kwon, Woo-Taeg;Kim, Hyung-Chul
    • Journal of Environmental Impact Assessment
    • /
    • v.17 no.4
    • /
    • pp.213-224
    • /
    • 2008
  • Since 1970's rapid urbanization and economic growth, the population was highly increased and residential type was changed from single detached house to high density and high-rise apartment. Recently more high-rise residential building generates more traffic volumes and it makes spatial concentration. The highly traffic volumed road and high residential building was constructed nearby, it occurs noise problem. The purpose of this study is comparing the performance of three type noise barrier between noise source and receiver using a noise map simulation. Three types were composed as road side planting trees, building side planting trees and noise barrier wall. Planting trees is less effective than noise barrier wall as a noise barrier. And they are all effective under 3 stories than over 5 stories, especially noise barrier function can't work over 5 stories.

Develop Conditions and Apply Plans of Greening Noise Barrier (식생 방음벽의 개발현황 및 적용방안에 관한 고찰)

  • 김경우;양관섭;안근영;김현수
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2001.11a
    • /
    • pp.133-138
    • /
    • 2001
  • Traffic noise is a significant national problem in many communities. Construction of noise barriers has been the most often used mechanism to mitigate vehicle noise for residents next to high density roadways. The most common materials for constructing noise barriers are metal. The character of the wall can be significantly modified by the type of surface treatment used on the wall body. Noise barrier walls can be softened through the use of plants. Greening Noise Barrier helps blend the roadway into the surrounding landscape and provides an interesting and aesthetic view of the road.

  • PDF

Interpretation of Material Characteristics and Making Techniques for Lime-Soil Mixture on Tomb Barrier of Pyeongtaek Gungri Site in Joseon Dynasty (평택 궁리유적 조선시대 회곽묘의 재료학적 특성 및 제작기법 해석)

  • Kang, San Ha;Lee, Chan Hee
    • Economic and Environmental Geology
    • /
    • v.51 no.1
    • /
    • pp.49-65
    • /
    • 2018
  • The lime-soil mixture on tomb barrier (LSMB) is a type of tomb in Joseon Dynasty, which made with so-called 'Sammul' (three material compound) that mixture of lime, fine sand and yellow ocher. This study divided the tombs of the Gungri Site from Joseon Dynasty with layered wall and integrated wall according to the manufacturing types, and investigated on the basis of analysis to material characteristics and making techniques. Analytical samples were classified with lime-soil mixtures and soils, and interpreted the mixing characteristics of Sammul based on types of tomb barrier. The tomb barrier which is directly effect to control the inner environment was made with high content of lime. But the finishing or bottom layer were made with low content of lime. Overall the LSMB with integrated wall has higher content of lime and physical property than the LSMB with layered wall. The soil which was compounded as a Sammul and collected near the Gungri Site had similar with mineralogical and geochemical characteristics. Therefore, it is presumed that the fine sand and yellow ocher that made as a Sammul, were used with soil that was distributed around the site. Meanwhile, large scale limestone quarry is distributed near the site. Especially, Gungri Site has a possibility of material supply through water transport, due to the sea route from Asan bay is connected near the site. Thus, there is the possibility of transportation of lime materials from nearby quarry.

Multi-Objective Optimization Study of Blast Wall Installation for Mitigation of Damage to Hydrogen Handling Facility (수소 취급시설 피해 저감을 위한 방호벽 설치 다목적 최적화 연구)

  • Se Hyeon Oh;Seung Hyo An;Eun Hee Kim;Byung Chol Ma
    • Journal of the Korean Society of Safety
    • /
    • v.38 no.6
    • /
    • pp.9-15
    • /
    • 2023
  • Hydrogen is gaining attention as a sustainable and renewable energy source, potentially replacing fossil fuels. Its high diffusivity, wide flammable range, and low ignition energy make it prone to ignition even with minimal friction, potentially leading to fire and explosion risks. Workplaces manage ignition risks by classifying areas with explosive atmospheres. However, the effective installation of a blast wall can significantly limit the spread of hydrogen, thereby enhancing workplace safety. To optimize the wall installation of this barrier, we employed the response surface methodology (RSM), considering variables such as wall distance, height, and width. We performed 17 simulations using the Box-Behnken design, conducted using FLACS software. This process yielded two objective functions: explosion likelihood near the barrier and explosion overpressure affecting the blast wall. We successfully achieved the optimal solution using multi-objective optimization for these two functions. We validated the optimal solution through verification simulations to ensure reliability, maintaining a margin of error of 5%. We anticipated that this method would efficiently determine the most effective installation of a blast wall while enhancing workplace safety.

Targeting of Large-molecule Radiopharmaceuticals across the Blood-brain Barrier Using Endogenous Transport Systems

  • Lee, Hwa-Jeong
    • Proceedings of the PSK Conference
    • /
    • 2002.10a
    • /
    • pp.94-95
    • /
    • 2002
  • Drug targeting to the central nervous system (CNS) is the limiting factor in CNS drug development because most of drug do not cross the brain capillary endothelial wall, which forms the blood-brain barrier (BBB) in vivo. One strategy for drug targeting to the brain is to use endogenous BBB transport systems. (omitted)

  • PDF

해안매립지에서의 추적자시험 및 수위변화특성 연구

  • 이진용;황대규;이명재;최예권;김정우;이강근
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
    • /
    • 2002.04a
    • /
    • pp.221-224
    • /
    • 2002
  • To demonstrate prevention of the leachate leakage out of the landfill with creating inward hydraulic gradient, a tracer test and continuous waterlevel monitoring at the Inside and outside of the barrier wall of a costal landfill were peformed. When the tracers were injected into the well outside of the vertical wall system with high water level, then they were detected at the well inside of the system with low water level. Furthermore the lowered water level at the inside of the landfill than that at the outside prevented leachate leakage out of the landfill. This study reports results of the tracer test and waterlevel monitoring.

  • PDF

Acridine Orange-induced Changes in Cell Wall of Salmonella pullorum (Acridine Orange에 의한 Salmonella pullorum의 세포벽 변화)

  • Kim, Jong-bae;Mah, Jum-sool
    • Korean Journal of Veterinary Research
    • /
    • v.25 no.2
    • /
    • pp.149-153
    • /
    • 1985
  • Salmonella pullorum strain W was serially passaged on the brain heart infusion agar containing acrdine orange(AO) as a concentration of 100 mcg/ml. S. pullorum AO60 and S. pullorum AO150, which were subcultured 60 and 150 passages on AO media, were examined for permeability barrier function of the cell wall. AO60 and AO150 were appeared to be decreased in susceptibility against hydrophobic substances such as crystal violet, chloramphenicol and rifamycin, which might be resulted from the changes of permeability barrier function of the cell wall. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis of bacterial protein, the protein profiles of AO6O and AO150 didn't differ significantly from W, but increased amount of the band of MW 140,000-145,000 was confirmed. And [G+C] contents of DNA in AO60 and A0150 were decreased than that of W.

  • PDF

CHEMICAL COMPATIBILITY OF SOIL-BENTONITE CUT-OFF WALL FOR IN-SITU GEOENVIRONMENTAL CONTAINMENT

  • Inui, Toru;Takai, Atsushi;Katsumi, Takeshi;Kamon, Masashi;Araki, Susumu
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2010.09c
    • /
    • pp.135-139
    • /
    • 2010
  • A construction technique to install the soil-bentonite (SB) cut-off wall for in-situ geoenvironmental containment by employing the trench cutting and re-mixing deep wall method is first presented in this paper. The laboratory test results on the hydraulic barrier performance of SB in relation to the chemical compatibility are then discussed. Hydraulic conductivity tests using flexible-wall permeameters as well as swell tests were conducted for SB specimens exposed to various types and concentrations of chemicals (calcium chloride, heavy fuel oil, ethanol, and/or seawater) in the permeant and/or in the pore water of original soil. For the SB specimens in which the pore water of original soil did not contain such chemicals and thus the sufficient bentonite hydration occurred, k values were not significantly increased even when permeated with the relatively aggressive chemical solutions such as 1.0 mol/L $CaCl_2$ or 50%-concentration ethanol solution. In contrast, the SB specimens containing $CaCl_2$ in the pore water had the higher k values. The excellent linear correlation between log k and swelling pressure implies that the swelling pressure can be a good indicator for the hydraulic barrier performance of the SB.

  • PDF

Evaluation of the feasibility of bony window repositioning without using a barrier membrane in sinus lateral approach (상악동측방접근법시 차폐막을 사용하지 않는 골창재위치술의 유용성 평가)

  • Jeon, Seung-Hwan;Cho, Yong-Seok;Lee, Byung-Ha;Im, Tae-Yun;Hwang, Kyung-Gyun;Park, Chang-Joo
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
    • /
    • v.37 no.2
    • /
    • pp.122-126
    • /
    • 2011
  • Introduction: In the lateral window approach for a maxillary sinus bone graft, there has been considerable controversy regarding the placement of a barrier membrane over the osteotomy site. In particular, when there is no damage to the Schneiderian membrane, clinicians should decide whether to use a barrier membrane or not, considering the benefits and costs. This study presents the clinical cases to demonstrate that only repositioning the detached window can lead to satisfactory bony healing of the grafted material without using a barrier membrane in the lateral approach for a maxillary sinus bone graft. Materials and Methods: Five consecutive patients were treated with the same surgical procedures. After performing the antrostomy on the lateral maxillary wall using a round carbide bur and diamond bur, the bony window was detached by a gentle levering action. After confirming no perforation of the Schneiderian membrane, the grafting procedure was carried out the detached window of the lateral maxillary wall was repositioned over the grafted material without using a barrier membrane. A gross examination was carried out at the postoperative 6 month re-entry, and the the preoperative and postoperative dental computed tomography (CT) at re-entry were compared. Results: All the procedures in the 5 patients went on to uneventful healing with no complications associated with the bone graft. Satisfactory bone regeneration without the interference of fibrous tissue on the gap between the repositioned window and lateral wall of the maxillary sinus was observed in the postoperative 6 month re-entry. The CT findings at re-entry revealed the, reconstruction of the external cortical plate including repositioned bony window. In addition, the loss of the discontinuity of the lateral maxillary wall was confirmed. Conclusion: This preliminary report showed that the detached window, which was just repositioned on the grafted material, could function as a barrier membrane in the lateral approach for a maxillary sinus bone graft. Therefore additional morphometric and histologic studies will be needed.