• Title/Summary/Keyword: Air permeability

Search Result 589, Processing Time 0.027 seconds

Changes of Physical Properties of Soils by Organic Material application (유기성 물질 시용에 따른 농경지 토양물리성 변화 연구)

  • Kim, Lee-Yul;Cho, Hyun-Jun;Han, Kyung-Hwa
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.37 no.5
    • /
    • pp.304-314
    • /
    • 2004
  • The objective of this study was to investigate the effect of organic materials (compost, straw, green manure, pig manure, seed production oil cake, and industrial by products including municipal sewage sludge, industrial sewage sludge, leather processing sludge, and alcohol fermentation processing sludge) on physical properties of soils in seven paddy and four upland fields with differential soil textures, sandy loam, loam, or clay loam, etc. The investigated physical parameters were bulk density (BD), air permeability (AP), macroporosity, hardness, shear resistance, frictional resistance, water stability aggregate (WSA), and Middleton's dispersion ratio. Except for coarse sandy loam field with weak structure, a decrease in BD and shear resistance, and an increase in macroporosity and AP in plots with applying organic materials compared to plots without applying organic materials appeared. In upland fields, the positive effect of organic materials on WSA, BD, and air permeability was higher than in paddy fields. The combined plot of NPK and compost had lower BD, hardness, and shear resistance, and higher macroporosity and WSA than plot with compost. Green manure had higher positive effect on physical properties of soils compared to other organic materials and the extent of positive effect had no significant correlation with soil organic matter content. Of industrial byproducts applied in coarse sandy loam soil under upland condition, municipal sewage sludge and pig manure compost had higher effect on increase of WSA than leather processing sludge and alcohol fermentation processing sludge. Unlike WSA, there were no significant differences between industrial byproduct types in other physical properties. in silty clay loam soil under the upland condition, straw had more positive effect on soil physical parameters than hairy vetch and pig manure. Therefore, different organic materials had differently active effect on physical parameters depending on types of soil and land use. Especially, it could be thought that well-decomposed organic materials have the advantage of an increase in organic matter content, while coarse organic materials of an increase in WSA.

Effect of Paper Bag Types and Harvesting Dates on Skin Blackening and Fruit Quality of 'Chuhwangbae' Pear Trees (봉지종류와 수확시기가 '추황배'의 수상에서의 과피흑변과 과실품질에 미치는 영향)

  • Choi, Jin-Ho;Yim, Sun-Hee;Kim, Sung-Jong;Kwon, Yong-Hee;Lee, Han-Chan;Jung, Seok-Kyu;Choi, Hyun-Sug
    • Korean Journal of Organic Agriculture
    • /
    • v.23 no.1
    • /
    • pp.91-101
    • /
    • 2015
  • 'Chuhwangbae' pears (Pyrus pyrifolia Nakai) were investigated on how types of paper bag and harvesting dates influenced on skin blackening before harvest as well as fruit quality after harvest. Experiments included four different types of paper bags (NP/YP, GP/YP, NP/BP, and NP/RP) and five different harvesting dates [160, 170, 180, 190, and 200 days after full bloom (DAFB)]. NP/YP and GP/YP indicated for newspaper- and gray paper-outer bag, respectively, with yellow paper-inner bag of the both. NP/BP and NP/RP indicated for newspaper-outer bag of the both with black paper- and red paper-inner bag, respectively. The NP/YP (newspaper/yellow paper) showed high absorbance and air and water vapor permeability in the bags, while the NP/RP (newspaper/red paper) resulted in poor physical properties in the bags. Fruit enclosed with NP/YP resulted in the absence of skin blackening, but fruit with NP/RP bags had the highest skin blackening (12.7%). Occurrence of skin blackening was concentrated on the middle and calyx end-part of fruit region. NP/RP bag treatment was likely to increase fruit weight, firmness, titratable acidity, and fruit surface color. Harvest at high relative humidity in air increased skin blackening of fruit. Later fruit harvest, such as 190 and 200 DAFB, increased skin blackening, fruit weight, and sugar content while decreasing fruit firmness and titratable acidity.

Influence of Humidity Variation on the Surface Deffects and Soft Magnetic Properties in the Fabrication of Fe Based Amorphous Alloy Ribbon by the PFC Process (PFC프로세스 의한 Fe기 Fe78Si9B13 비정질 합금리본 제조에 있어서 습도변화가 표면결함 및 연자기적 특성에 미치는 영향)

  • Choi, Y.J.;Jang, S.J.;Kim, S.W.;Jeon, B.S.;Kim, S.M.;Song, C.B.;Kim, Y.C.;Namkung, J.
    • Journal of the Korean Magnetics Society
    • /
    • v.25 no.1
    • /
    • pp.4-9
    • /
    • 2015
  • This study was carried out to investigate a influence of humidity variation (%) on the magnetic properties and the surface flaws in the fabrication of Fe-based $Fe_{78}Si_9B_{13}$ amorphous alloy ribbon by Planar Flow Casting process. As a result, the size of the air pocket and the droplet which is observed in the contact surface and the free face of the amorphous alloy ribbon becomes large when the humidity increases and the size highly increases with the surface roughness at the same time. Especially, the surface roughness value which is made in the 65 % of the humidity is the lowest in the contact surface ($Ra=0.60{\mu}m$, $Rz=3.11{\mu}m$) and the free face ($Ra=0.47{\mu}m$, $Rz=3.00{\mu}m$). Also, in case of the soft magnetic property of the magnetic core which is made with the toroidal core of $23(OD)^*20(ID)^*20(H)$ size, in the sample of the amorphous alloy ribbon which is made in 65% of the humidity, the most excellent value is gained as $B_s(B_{700})=1.055T$, $H_c=0.083Oe$, permeability = 1,197 and core loss = 0.276W/kg.

Preparation and Oxygen Permeability of Nb-doped BCFN Ceramic Membrane (Nb-doped BCFN 세라믹 막의 제조 및 산소투과 특성)

  • Kim, Jong-Pyo;Son, Sou-Hwan;Park, Jung-Hoon;Lee, Yong-Taek
    • Membrane Journal
    • /
    • v.21 no.1
    • /
    • pp.55-61
    • /
    • 2011
  • $BaCo_{0.7}Fe_{0.22}Nb_{0.08}O_{3-{\delta}}$ oxide was synthesized by solid state reaction method. Dense ceramic membrane was prepared using as-prepared powder by pressing and sintering at $1,200^{\circ}C$. XRD result of membrane showed single perovskite structure. Leakage and oxygen permeation test were conducted on the membrane sealed by glass ring as a sealing material. The oxygen permeation flux increased with increasing temperature and pressure difference and maximum oxygen permeation flux was $2.3mL/min{\cdot}cm^2$ at $950^{\circ}C$ with $Po_2$ = 0.63 atm of oxygen partial pressure. The oxygen permeation in the condition of air with $CO_2$ (300 ppm) as feed stream decreased as much as only maximum 2.9% in comparison with air feed stream. It indicated $BaCo_{0.7}Fe_{0.22}Nb_{0.08}O_{3-{\delta}}$ membrane is more stable than another membrane for carbon dioxide.

A Study on Clogging during Installation of Compaction Pile (다짐말뚝 시공 시 공극 막힘 현상 분석 연구)

  • Choi, Jeong Ho;Park, Seong Jin;Choo, Yun Wook;Kim, Il Gon;Kim, Byeong Kyu
    • Journal of the Korean Geotechnical Society
    • /
    • v.38 no.4
    • /
    • pp.33-45
    • /
    • 2022
  • A series of model tests were performed in this study to demonstrate the clogging mechanism created during the installation of a compaction pile to improve soft ground. The application of an air-jet to extrude sand or aggregates from a casing during the installation of a compaction pile imposes a remarkably high-pressure difference between the composite soil layers of clay and sand (or aggregates), resulting in severe clogging. Therefore, a one-dimensional testing system was developed to simulate composite soil layers consisting of clay and sand (or aggregates) and to apply a high-pressure differential at both boundaries, thus replicating the extrusion process used in compaction pile installation. Herein, the performance of two construction materials for compaction piles of crushed stone and grading-controlled aggregates was compared. A series of one-dimensional model tests were performed under multiple pressure settings, with clogging depth and permeability measured in each case. Results indicate that, blinding clogging mechanisms and blocking defined by previous studies were observed for crushed stone, and a new mechanism of "infiltration" was revealed and defined. Whereas, the controlled aggregates performed excellently against clogging because only blinding was observed.

Effect of Construction Joint on Leakage Resistance of Gas in Reinforced Concrete Pressure Vessels (철근콘크리트 압력용기에서 시공이음이 가스의 누설저항에 미치는 영향)

  • Yi, Seong-Tae
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.21 no.2
    • /
    • pp.87-94
    • /
    • 2017
  • In the nuclear power plant, the steel or polymer liner plates are adopted to prohibit the inner concrete surface from contacting with gas or liquid materials. If there is an accident, the plate may be damaged, and, in this case, concrete shall have the final responsibility to safety requirements. In this paper, an experimental research was carried out to investigate the effects of construction joint and wet and loading conditions on the permeability of concrete. The test results showed that, under a construction joint in the wet condition, leakage of gas pressure has been started from $1kg/cm^2$. However, when there are no construction joints, it is initiated from $2kg/cm^2$. In addition, under the air dried and unloading condition, regardless of with or without the presence of the construction joint, since the gas passage that exist in concrete is constant, leakage has a constant tendency to increase. Finally, under the loading condition, as described in Reference 1, since leakage is inversely proportional to the thickness of the wall, and, considering the wall thickness of the actual plant, it is found that there will not be no problem in the sealing of the gas.

Fundamental Properties of MgO Base Ceramic Mortar for Concrete Repair Material (MgO계 세라믹 모르타르를 활용한 콘크리트 보수재료의 기초물성평가)

  • Park, Joon-Woo;Ann, Ki-Yong
    • Journal of the Korea Concrete Institute
    • /
    • v.29 no.4
    • /
    • pp.407-413
    • /
    • 2017
  • The fundamental property of magnesia phosphate cement (MPC) for concrete repair material was investigated in this research. For mechanical properties, setting time, compressive strength and tensile/flexural bond strength were measured, and hydration products were detected by X-ray diffraction. The specimens were manufactured with dead burnt magnesia and potassium dihydrogen phosphate was admixed to activate the hydration of magnesia and a borax was used as a retarder. To observe the pore structure and ionic permeability of MPC mortar, mercury intrusion porosimetry was performed together with rapid chloride penetration test (RCPT). As a result, time to set of Fresh MPC mortar was in range of 16 to 21 min depend on the M/P ratio. Borax helped delaying setting time of MPC to 68 min. The compressive strength of MPC with M/P of 4 was sharply developed to 30 MPa within 12 hours. The compressive strength of MPC mortar was in range of 11.0 to 30.0 MPa depend on the M/P ratio at 12 hours of curing. Both tensile and flexural bond strength of MPC to old substrate (i.e. MPC; New substrate to OPC; Old substrate) were even higher than ordinary Portland cement mortar (i.e. [OPC; New substrate] to [OPC; Old substrate]) does, accounting 19 and 17 MPa, respectively. The total pore volume of MPC mortar was lower than that of OPC mortar. MPC mortar had the entrained air void rather than capillary pore. The RCPT showed that total charge passed of OPC mortar had more than that of MPC mortar, which can be explained by the pore volume and pore distribution.

Effect of Mixed Bed Soil on Growth of Aerial Parts and Roots of Daughter Pants for Nursery Field Srawberry Seedling Raising with Expanded Rice-hull (딸기 팽연왕겨 차근육묘를 위한 혼합상토 조성이 자묘의 지상부 생육과 발근에 미치는 영향)

  • Park, Gab-Soon;Kim, Young-Chil;Kim, Myung-Seon;Ann, Seoung-Won
    • Journal of Environmental Science International
    • /
    • v.24 no.2
    • /
    • pp.189-196
    • /
    • 2015
  • This study was performed to identify the effect of mixed bed soil on growth of aerial parts and root zone of daughter plants for nursery field strawberry seedling raising with expanded chaff. The plant height and leaf area of daughter plants were highest or largest in the mixed soil of ERH +RH (100:0, v/v), followed by ERH+RH (75:25). The higher the mixing ratio of RH, the shorter the plant height or the smaller the leaf area. A similar tendency was observed in fresh weight. Within a root diameter of 0-0.4 mm and a root height range of 0.4-0.8 mm, root surface area and volume were statistically significantly better with treatment of ERH+RH (100:0, v/v) compared to those of roots treated with ERH+RH (75:25), ERH+RH (50:50) and ERH+RH (25:75). The growth rate of aerial parts and root zone of daughter plants were noticeably lower in two mixing ratios of 50:50 and 25:75. According to the mixing ratios of ERH+CD surface treatment, the number of roots was greatest in plants treated with ERH+CD (80:20, v/v) and ERH+CD (85:15) on August 1. However, the number of roots was highest in plants treated with ERH+CD (85:15, v/v) on August 15. Root length was longest in the plant with no treatment, and drastically shortened from ERH+CD (90:10, v/v) in both surface and mixed treatment. Although root weight showed a significant difference in ERH+CD (90:10, v/v) treatment, its increase was gradual. The rate of root growth was highest in ERH+CD (85:15). These study findings suggest that the content ratios of mixed soil ERH+RH (75:25, v/v) or below and ERH+CD (85:15) are thought to be desirable for the production of high quality seedlings.

Functional Modification of Sanitary Nonwoven Fabrics by Chitosan Treatment (Part II) -Focused on Changes in Physical Properties- (키토산 처리에 의한 위생용 부직포의 기능성 개질화 (제2보) -물성 변화를 중심으로-)

  • Bae, Hyun-Sook;Kang, In-Sook;Park, Hye-Won;Ryou, Eun-Jeong;Kwon, Jay-Cheol
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.31 no.12
    • /
    • pp.1662-1671
    • /
    • 2007
  • The change in physical properties of polypropylene nonwoven fabrics used as top sheet for disposable sanitary goods was carried out using chitosan that is a type of natural polymer and has excellent human affinity by varying the molecular weight and concentration of chitosan. Low molecular weight(LMW) chitosan treated fabrics were found to be evenly coated on fabrics and had better dyeability by apparent dye uptake and its deodorization rate increased over the time. On the other hand, high molecular weight(HMW) chitosan treated fabrics showed higher add-on ratio and its dynamic water absorption rate and represented an increase in water transport rate. With chitosan treatment, its air permeability was improved. Regardless of the type of bacteria and chitosan concentration, its antibacterial activity was excellent in the case of the HMW chitosan treatment. In this regard, chitosan treatments by using a relatively high molecular weight was found as an effective way in the functional improvement of moisture properties and antibacterial activity including their most important performance in sanitary nonwoven fabrics.

Effect of Some Soil Conditioners on Soil Physical Properties and Tobacco Growth (토양개량제 시용이 토양물리성과 담배생육에 미치는 영향)

  • 이철환;진정의;한철수
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.41 no.6
    • /
    • pp.685-691
    • /
    • 1996
  • This experiment was conducted to investigate the effect of some soil conditioners, such as polyvinylalcohol(PVA), zeolite and perlite, on the changes of soil physical properties and on tobacco growth in paddy-upland rotated field. Soil conditioners were treated at the rates of 120kg in PVA, 500kg in zeolite and perlite per l0a, respectively. Ratio of soil aggregates formed from the treated plots tended to. be higher than those from the control in the order of PVA > perlite > zeolite. The wet aggregate stability, mean weight diameter, moisture retention and air permeability from the treated plots tended to be higher than those from the control. Amounts of water-stable aggregates of PV A-treated soil increased with higher soil moisture showing a peak at 50% of moisture content. But with respect to particle of size aggregate formed for crop growth and workability in field, it was presumed that 40% of soil moisture content would be most desirable. Visual characters of soil surface throughout the experiment clearly showed that treated soils were maintaining better surface roughness and porosity than control, but difference in water stable aggregates among treated plots tended to be narrowed. The growths of tobacco, espacially its root zone were better in conditioner treated plots than in non-treated plot showing best in PVA-treated soil.

  • PDF