• Journal of the Korea Furniture Society
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• v.18 no.4
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• pp.261-267
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• 2007

This report describes the wood anatomy and 1% safranine solution penetration depth in radial and longitudinal directions of Anthocephalus chinensis belonging to the family Rubiaceae native to Bangladesh. The wood of this species was mostly characterized by diffuse porous, vessel with simple perforation plate, vestured alternate intervessel pittings, relatively medium vessel elements and fiber, and nonseptate fiber with distinctly bordered pits at radial wall. The body ray cell was procumbent with 2 to over 4 rows of upright and square marginal cells. Sometimes, the rays with procumbent, square and upright cells were mixed. Latewood fiber was thin to thick walled while it was very thin walled in earlywood. Axial parenchyma was diffuse, vasicentric, 5-8 cells per parenchyma strand dominantly present. Liquid penetration depth was observed in radial and longitudinal directions at moisture level of 7.42%. Longitudinal penetration was found 6.3 times higher than radial penetration. The initial penetration rate of safranine solution was high, but gradually decreased during the course of time. Different anatomical features were found to be responsible for the variation of safranine solution penetration depth compared to Gmelina arborea.

• Korean Journal of Environmental Agriculture
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• v.35 no.4
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• pp.263-269
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• 2016

BACKGROUND: The personal protective equipments (PPEs) is the most important factor for reducing the pesticide exposure during the preparation and spraying of pesticides. This study was to investigate the retention, repellence and penetration of protective clothing of PPEs according to the ISO 22608 'Liquid penetration resistance-pipette test. Protective clothing for agriculture worker is very important for their health. However, test method for measurement of protective clothing is not presented in Korea. METHODS AND RESULTS: In order to measure the retention, repellence and penetration of protective clothing, a apparatus for pipette method in accordance with the ISO Guideline was prepared. The test was conducted at $25{\pm}5^{\circ}C$, $60{\pm}10%$ of relative humidity and pipette applied to a apparatus was validated to take exact amount(0.2 mL). The retention, repellence and penetration of five types of protective clothing and one type of shirt were analyzed by GC/MS. Pendimethalin(5% a.i, emulsion) was used as a test pesticide to measure above factors. The retention were less than 11.0% with the exclusion of two types(F4 and shirt) and the repellency was more than 67.0% with the exclusion of shirt material. The penetration was less than 5.4%, however, that of shirt was 66.7%. CONCLUSION: This results indicated that all protective clothing were suitable to use as PPEs according to the criteria specified by ISO Guide 22608. However, shirt was not suitable due to high penetration. This test method established for measurement the retention, repellence and penetration of protective clothing will help to establish the test notice of pipette method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.140-152
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• 1989

The study on the penetration of sprays during the initial phase of injection period, i.e. ignition delay period, in high speed small D.I. diesel engines are strongly affected by such behavior. To investigate the penetration of the sprays injected through single cylinderical orifice, a mathematical model was developed and compared with experimental results. In this model, radial heterogeneity of fuel density in the spray, transiency of injection pressure difference, and spray outrunning phenomenon were considered simultaneously. Experiments on the behaviors of sprays in the high pressure air chamber were conducted at various injection pressure differences and different levels of back air pressure. The behaviors of sprays injected into the chamber through the conventional Bosch injection pump were visualized with side stroboscopic illumination. Comparison of the experimental results with predictions from the mathematical model confirmed the validity of the model. It was also found that during the initial phase of the injection period the penetration of sprays vs. time appeared to have two transition points; one corresponded to disintegration point of liquid fuel jet, the other to the beginning of steady state injection.

• Journal of the Korea Furniture Society
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• v.18 no.2
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• pp.138-142
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• 2007

Optical microscope was used to observe the difference of safranine penetration in Pinus densiflora, Pinus rigida, Pinus koraiensis and Larix kaempferi grown in Korea. It was found that Pinus koraiensis contained the highest number of ray parenchyma and ray tracheids. In longitudinal direction, latewood penetration was found higher than that of earlywood. The number of resin canals was found highest in Pinus koraiensis and lowest in Pinus rigida. The resin canal conducted safranine higher than longitudinal tracheids. In longitudinal direction, safranine diffused from longitudinal tracheid to ray parenchyma through the cross-field pits and from the longitudinal resin canal to ray parenchyma or longitudinal tracheid. Safranine diffused from longitudinal tracheid to its neighboring tracheid through bordered pit or ray parenchyma through the cross-field pits.

• Journal of ILASS-Korea
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• v.13 no.4
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• pp.180-186
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• 2008

The aim of this work is to investigate the effect of ambient conditions on the spray behavior of biodiesel-ethanol blended fuels. In order to analyze the spray behavior, spray tip penetration and spray cone angle were obtained from the visualization system and the effects of ethanol blending are compared macroscopic characteristics with the numerical results. It was reveled that the ethanol contents in biodiesel-ethanol blended fuels affect the spray tip penetration a little and increased the spray cone angle. Increased ambient pressure induced the decrease of the spray tip penetration, and the increased ambient temperature lead to the increase of the spray tip penetration. In addition, the increased ambient temperature promoted the vaporization and atomization of spray with the effect of increasing ethanol fuel.

• Journal of ILASS-Korea
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• v.17 no.2
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• pp.77-85
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• 2012

The CFD simulation of diesel spray tip penetrations were compared with 0-D simulation for experimental data obtained with common rail injection system. The simulated four injection patterns include single, pilot and split injections. The CFD simulation of the spray penetration over these injection patterns was performed using the KIVA-3V code, which was implemented with both the standard KIVA spray and original gas jet sub-models. 0-D simulation of the spray tip penetration with time-varying injection profiles was formulated based on the effective injection velocity concept as an extension of steady gas jet theory. Both the CFD simulation of the spray tip penetration with the standard KIVA spray model and 0-D simulation matched better with the experimental data than the results of the gas jet model for the entire fuel injection patterns.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.8-19
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• 2001

A number of atomization and droplet breakup models have been developed and used to predict the diesel spray characteristic. Most of these models could not provide reasonable computational result of the diesel spray characteristic because they have only considered the primary breakup. A hybrid model is, therefore, required to develop by considering the primary and secondary breakup of liquid jet. according to this approach, wave breakup(WB) model was used compute the primary breakup of the liquid jet and droplet deformation and breakup(DDB) model was used for the secondary breakup of droplet. Development of hybrid model by using KIVA-II code was performed by comparing with the experimental data of spray tip penetration and SMD from the literature. A hybrid model developed in this study could provide the good agreement with the experimental data of spray tip penetration. The prediction results of SMD were in good agreement between 0.5 and 1.0 ms after the start of injection. Numerical results obtained by the present hybrid model have the good agreement with the experimental data with the breakup time constant in WB model of 30, and DDB model constant Ck of 1.0 when the droplet becomes less than 95% of maximum droplet diameter injected.

• Journal of ILASS-Korea
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• v.10 no.4
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• pp.47-53
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• 2005

This paper presents the effects of ambient pressure on atomization characteristics of high-Pressure injector in a direct injection gasoline engine both experimentally and numerically. The atomization characteristics such as mean droplet size, mean velocity, and velocity distribution were measured by phase Doppler particle analyzer. The spray development, spray penetration, and global spray structure were visualized using a shadowgraph technique. In order to investigate the atomization process numerically, the LISA-DDB hybrid model was utilized. This breakup model assumes that the primary breakup occurs when the amplitude of the unstable waves is equal to the radius of the ligament of liquid sheet near the nozzle and the droplet deformation induces the secondary breakup. The results provide the effect of ambient pressure on the macroscopic and microscopic behaviors such as spray development, spray penetration, mean droplet size, and mean velocity distribution. It is also revealed that the accuracy of prediction of LISA-DDB hybrid model is pretty good in terms of spray developing process, spray tip penetration, and SMD distribution.

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.703-717
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• 2005

The infiltration of ceramics by liquid metals to fabricate ceramic-metal composites is discussed. In particular, the complexity of infiltrating ceramics by liquid metals at high temperatures due to interfacial reactions, metal oxidation, pore modulation and closure, and transient capillary forces has been highlighted. The role of these factors is discussed in the context of reactive infiltration with examples from ceramic/metal composites of practical interest. In addition to flow through porous ceramics, reactive penetration of dense ceramics via chemical dissolution and reaction is also discussed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.18-23
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• 2002

Liquid phase mixing of impinging injector is a resultant byproduct from the momentum exchange between a pair of impinging jets and penetration of opponent jet. Principal aim of the present study is revealing the liquid phase mixing mechanism of split triplet impinging injection sprays, and thus extending our understanding on this particular injection element. Overall mixing extent is estimated from patternation tests by the use of purified tap water and kerosene to simulate the real propellant components, respectively, and with the liquid jet momentum ratio, a controlling mixing parameter, in the range of 0.5 to 6.0. Emphasis is placed on the effect of liquid sheet superposition and disintegration, and the results with detailed spray visualization revealed the fact that superposed liquid sheet disintegration is the main pathway of liquid phase mixing of split triplet impinging injector to yield enhanced mixing qualities.