• Title/Summary/Keyword: spraying thickness

Search Result 83, Processing Time 0.029 seconds

The Study on the Selection of Revegetation Methods on Weathered Granite Cut-soil Slopes (화강풍화토 흙깎기 비탈면 녹화공법 선정 방안 연구)

  • Kim, Nam-Choon
    • Journal of the Korean Society of Environmental Restoration Technology
    • /
    • v.19 no.2
    • /
    • pp.121-135
    • /
    • 2016
  • The present study is an analysis of the monitoring results of the four areas that underwent the experimental construction of Straw-net+seedspray, Vegetation media spray method(t=2cm), and Vegetation media spray method(t=3cm), with the purpose of selecting the adequate revegetation of cutting slopes in weathered granite soil. Cutting slopes are mostly designed in the Straw-net+seedspray method, but since weathered granite soil slopes tend to have an infertile soil quality that runs down, it is difficult for seed germination and growth. It is difficult to apply Straw-net+seedspray to weathered granite soil slopes considering the germination rate and coverage rate of the Straw-net+seedspray method, which accompanies erosion and scouring. The final conclusions are summarized as follows. First, Straw-net+seedspray has difficulty recruiting plants to infertile weathered granite soil, which results in a lower coverage rate and fewer species, so it is not adequate construction method. Second, Vegetation spraying methods with wet media are more advantageous in early revegetation. The wet construction methods are faster than the dry construction methods in terms of early germination and its early growth are more excellent. Third, when constructing Vegetation spray methods with dry media, it were more advantageous if the thickness was thicker. When the soil-media is thicker, the soil is resilient to droughts, so the thickness must be flexibly applied according to the soil quality and slant of the weathered granite soil slope. The present study is a monitoring result for some areas of Gangwon-do, so its results may differ from other areas.

Corelation between crystalline phase and corrosion resistance of Mg alloy with different PEO conditions. II. Corrosion resistance (Mg 합금의 PEO 공정 조건에 따른 산화피막 결정상과 내부식성에 대한 연구 II. 내부식성)

  • Kim, Bae-Yeon;Kim, Yong-Nam;Jeon, Min-Seok;Ham, Jae-Ho
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.28 no.2
    • /
    • pp.80-84
    • /
    • 2018
  • Mg alloys AZ31 and AZ91 were Plasma-Electrolytic-Oxidized in Na-P and Na-Si system electrolyte at various concentration, applied voltage and time. Thickness and surface roughness of PEO coating were examined. Salt spraying test were carried out to compare their corrosion resistances. Generally, corrosion resistances rate were increased as thickness and crystallinity increasing. Size of pore being larger, long term corrosion resistance decreased. It is turned out that $Mg_2SiO_4$ and other crystalline phase rather than MgO might be increase corrosion resistance dramatically.

A Study on the high Temperature Properties of the Graded Thermal Barrier Coatings by APS and PAS (APS법으로 제조된 열장벽 피막과 PAS법으로 제조된 열장벽 성형체의 고온 물성에 관한 연구)

  • 강현욱;권현옥;한주철;송요승;홍상희;허성강;김선화
    • Journal of the Korean institute of surface engineering
    • /
    • v.32 no.2
    • /
    • pp.144-156
    • /
    • 1999
  • Thermal Barrier Coating with Functional Gradient Materials (FGM-TBC) can play an important role to protect the parts from harmful environments in high temperatures such as oxidation, corrosion, and wear and to improve the efficiency of aircraft engine by lowering the surface temperature on turbine blade. FGM-TBC can increase the life spans of product and improve the operating properties. Therfore, in this study the evaluations of mechanical and thermal properties of FGM-TBC such as fatigue, oxidation and wear-resistance at high temperatures have been conducted. The samples of both the TBC with 2, 3, 5 layers (YSZ/NiCrAlY) to be produced by Air Plasma Spray method (APS) and the bulk TBC with 6 layers to be produced by Plasma Assisted Sintering method (PAS) were used. Furthermore, residual stress, bond strength, and thermal conductivity were evaluated. The average thickness of the APS was 500$\mu\textrm{m}$ to 600$\mu\textrm{m}$ and the average thickness of the PAS was 3mm. The hardness number of the top layer of APS was 750 Hv to 810Hv and that of PAS was 950 Hv to 1440Hv. The $ZrO_2$ coating layer of APS was composed of tetragonal structure after spraying as the result of XRD analysis. As shown in the results of the high temperature wear test, the 3 layer coating of APS had the best wear resistance at $800^{\circ}C$ and the 5 layer coating of APS had the best wear resistance at $600^{\circ}C$. But, these coatings had the tendency of the low-temperature softening at $300^{\circ}C$. The main mechanism of wear was the adhesive wear and the friction coefficient of coatings was increased as increasing the test temperatures. A s results of thermal conductivity test, the ${\Delta}T$ of the APS coating was increased as number of layer and the range of thermal conductivity of the PAS was $800^{\circ}C$ to $1000^{\circ}C$.

  • PDF

Effect of Panel Density and Resin Content on Properties of Medium Density Fiberboard

  • Hong, Min-Kug;Lubis, Muhammad Adly Rahandi;Park, Byung-Dae
    • Journal of the Korean Wood Science and Technology
    • /
    • v.45 no.4
    • /
    • pp.444-455
    • /
    • 2017
  • This study was conducted to evaluate the effect of panel density and resin content on properties of medium density fiberboard (MDF) to obtain some insights on MDF properties as a function of panel density and resin content. MDF panels with different panel densities such as 650, 700, 750 and $800kg/m^3$ were manufactured by adjusting the amount of wood fibers in the mat forming. MDF panels were also fabricated by spraying 8, 10, 12, and 14% of urea-formaldehyde (UF) resins onto wood fibers in a drum-type mechanical blender to fabricate MDF panels with a target density of $650kg/m^3$. As the panel density and resin content increased, the internal bonding (IB) strength of MDF panel consistently increased. Modulus of rupture (MOR), modulus of elasticity (MOE) and screw withdrawal resistance (SWR) had a similar trend to the IB strength. In physical properties, thickness swelling (TS) and water absorption (WA) decreased with an increase in both panel density and resin content. In addition, the formaldehyde emission (FE) which increased as the panel density and resin content became greater. In overall, the panel density of MDF had more significant effect than the resin content in all properties of MDF panels, indicating that it was better to adjust the panel density rather than the resin content for MDF manufacture.

The Measurement Method of Thermal Conductivity and Diffusivity of Thin Paint Layer Sprayed on Solid Surface (고체표면에 도포한 도료 박막의 열전도율과 열확산율의 측정법)

  • Kim, Eun-young;Park, Soo-Chun;Kim, Byung-Mun;Lee, Doug-Bong
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.23 no.3
    • /
    • pp.311-319
    • /
    • 1999
  • The thermal conductivity ${\lambda}_b$, thermal diffusivity ${\alpha}_b$ of the thin black paint layer sprayed on solid surface and absorptivity a for laser beam are measured by applying a non-contact measurement method of the thermophysical properties of solids. The values of a=0.67, ${\lambda}_b=1.45W/mK$ and ${\alpha}_b=1.24{\times}10^{-6}m^2/s$ are obtained for the sprayed lay~ thickness $z_b{\fallingdotseq}40\;{\mu}m$. Furthermore, for the $z_b{\fallingdotseq}24\;{\mu}m$ thick layers which arc formed by rubbing with a glass rod after spraying, the values of a=0.73, ${\lambda}_b=1.85W/mK$. and ${\alpha}_b=1.09{\times}10^{-6}m^2/s$ are obtained. It is also shown that the present thermal diffusivity ${\alpha}_b$ for $z_b{\fallingdotseq}40\;{\mu}m$ Is about 30~80% larger than those obtained by Araki et al. for the thicker layer $z_b{\fallingdotseq}150{\sim}248\;{\mu}m$. This method could be applied to the measurement of thermophysical properties of thin layer on solids.

Ultrastructures of Colletotrichum orbiculare in Cucumber Leaves Expressing Systemic Acquired Resistance Mediated by Chlorella fusca

  • Kim, Su Jeung;Ko, Eun Ju;Hong, Jeum Kyu;Jeun, Yong Chull
    • The Plant Pathology Journal
    • /
    • v.34 no.2
    • /
    • pp.113-120
    • /
    • 2018
  • Chlorella, one single-cell green algae organism that lives autotrophically by photosynthesis, can directly suppress some plant diseases. The objective of this study was to determine whether pre-spraying with Chlorella fusca suspension could induce systemic acquired resistance (SAR) in cucumber plants against anthracnose caused by Colletotrichum orbiculare. In order to illustrate SAR induced by algae, infection structures in host cells were observed under a transmission electron microscope (TEM). Cytological changes as defense responses of host mesophyll cells such as accumulation of vesicles, formation of sheath around penetration hyphae, and thickness of cell wells adjoining with intracellular hyphae were demonstrated in cucumber leaves. Similar defense responses were also found in the plant pre-treated with DL-3-aminobutyric acid, another SAR priming agent. Images showed that defense response of host cells was scarcely observed in untreated leaf tissues. These cytological observations suggest that C. fusca could induce SAR against anthracnose in cucumber plants by activating defense responses of host cells.

Effect of Ti Intermediate Layer on Properties of HAp Plasma Sprayed Biocompatible Coatings

  • Take, Seisho;Otabe, Tusyoshi;Ohgake, Wataru;Atsumi, Taro
    • Corrosion Science and Technology
    • /
    • v.19 no.2
    • /
    • pp.51-56
    • /
    • 2020
  • The objective of this study was to improve properties of plasma sprayed HAp layer to titanium substrate by introducing an intermediate layer with two different methods. Before applying Zn doped HAp coating on titanium substrate, an intermediate layer was introduced by titanium plasma spray or titanium anodization. Heat treatments were conducted for some samples after titanium intermediate layer was formed. Zn doped HAp top layer was applied by plasma spraying. Three-point bending test and pull-off adhesion test were performed to determine the adhesion of Zn doped HAp coatings to substrates. Long-term credibility of Zn doped HAp plasma sprayed coatings on titanium was assessed by electrochemical impedance measurements in Hanks' solution. It was found that both titanium plasma sprayed and titanium anodized intermediate layer had excellent credibility. Strong adhesion to the titanium substrate was confirmed after 12 weeks of immersion for coating samples with titanium plasma sprayed intermediate layer. Samples with titanium anodized intermediate layer showed good bending strength. However, they showed relatively poor resistance against pulling off. The thickness of titanium anodized intermediate layer can be controlled much more precisely than that of plasma sprayed one, which is important for practical application.

Repair and Strengthening Methods for Concrete Structures using Sprayed Fiber Reinforced Polymers - Material Property of Sprayed FRP - (Sprayed FRP 공법에 의한 콘크리트 구조물의 보수.보강법 개발에 관한 연구 - Sprayed FRP를 구성하는 재료특성에 관한 연구 -)

  • Lee, Li-Hyung;Lee, Kang-Seok;Son, Young-Sun;Byeon, In-Hee;Lim, Byung-Ho;Na, Jung-Min
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2006.11a
    • /
    • pp.141-144
    • /
    • 2006
  • The main purpose of this study is to develop a Sprayed FRP repair and strengthening method, which is a new technique for strengthening the existing concrete structures by mixing carbon or glass shot fibers and the epoxy or vinyl ester resins with high-speed compressed air in open air and randomly spraying the mixture onto the concrete surface. At present, the Sprayed FRP repair and strengthening method using the epoxy resin has not been fully discussed. In order to investigate the material property of Sprayed FRP, this study carried out tensile tests of the material specimens which are changed with the combinations of various variables such as the length of shot fiber and mixture ratio of shot fiber and resin. These variables are set to have the material strength equal to one layer of the FRP sheet. As a result, the optimal length of glass and carbon shot fibers were derived into 3.8cm, and the optimal mixture ratio was also deriver into 1:2 from each variable. And also, the thickness of Sprayed FRP to have the strength equal to one layer of FRP sheet was finally calculated.

  • PDF

Crystalline Phases and Superconductor Characteristics of the Plasma Sprayed YBa2Cu$\chi$O7-y High Tc Superconductor Thick Film (플라즈마 용사법에 의해 제조된 YBa2Cu$\chi$O7-y(X=3, 3.5, 4) 고온초전도체 후막층의 결정상 및 초전도 특성)

  • 한명섭;서동수
    • Journal of the Korean Ceramic Society
    • /
    • v.29 no.2
    • /
    • pp.152-160
    • /
    • 1992
  • High-Tc superconductor thick films of YBa2Cu$\chi$O7-y (X=3, 3.5, 4) of which thickness varies from 100 $\mu\textrm{m}$ to 200 $\mu\textrm{m}$ were successfully prepared by plasma spraying method, and the characteristics of thick film depending on copper content and heat treatment conditions were investigated. Regardless of heat-treated temperature, the specimens with X=3 were composed of YBa2Cu$\chi$O7-y, Y2BaCuO5 and BaCuO3 phases. The specimens with X=4, however, were composed of YBa2Cu$\chi$O7-y phase at all heat treatment conditions. The specimens with X=4 composition showed the best superconducting characteristics after heat treatment at 925$^{\circ}C$, and the superconducting transition temperature with zero resistivity (Tc,zero) was 87K. The thick film lost superconductivity when the specimens were heat-treated at 950$^{\circ}C$ because of interdiffusion between superconductor elements and bond coating elements and Y2BaCuO5 phase was found was found to be main phase at the interface.

  • PDF

A study on the thermal properties of the 11 layer thermal barrier (11층 열장벽 피막의 고온물성에 관한 연구)

  • 권현옥;강현욱;남영민;송요승;홍상희;현규택;윤종구;이득용;김선화
    • Journal of the Korean institute of surface engineering
    • /
    • v.34 no.1
    • /
    • pp.3-9
    • /
    • 2001
  • The purpose of this study is to evaluate the properties of the functional gradient thermal barrier coatings by plasma spray process. The evaluations of mechanical and thermal properties such as fatigue, oxidation and wear-resistance at high temperatures have been conducted. Furthermore, residual stress and bond strength have been evaluated. The range of thickness of coated layers was 550~600$\mu\textrm{m}$. The range of hardness of layers was 800~900 Hv and the porosity range of coatings was about 7 to 14%. The top coating layer of $ZrO_2$ in thermal barrier was composed of tetragonal structure after spraying. The coated layers of $ZrO_2$ on the Inconel substrate is the best resistance for thermal fatigue. Those coatings had the least compressive stress in comparison with other coatings. In high temperature oxidation test, the coatings on Inconel substrate was better than the coatings on SUS substrate. The bond strength of the concave type was greater than that of linear types and convex types coatings.

  • PDF