• Title/Summary/Keyword: Design length

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Numerical Analysis of Load Reduction for Underground Arch Structures with Soft Zone Using Expanded PolyStyrene Geofoam (EPS Geofoam을 이용한 Soft Zone 적용방법에 따른 지중아치구조물의 하중저감에 관한 해석 연구)

  • Kim, Soo-Ha;Park, Jong-Sup;Kang, Jun-Suk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.10
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    • pp.24-30
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    • 2018
  • As the demand for underground space increases, many researchers have been studying the load reduction method using high compressible materials to solve for the stability problem of the overhead load and for the increase of the earth pressure which decreases the function of the underground structure. This paper determines the optimum soft zone and the effect of the using EPS Geofoam as a load reduction material to arch structures. A finite element analysis program, ABAQUS, is used to analyze the soil-structure interaction and the behavior of buried arch structures considering different four EPS Geofoam forms to confirm the most conservative shape. The optimum cross-sectional shape was determined by comparing the results of earth pressure reduction rate in accordance with the change of span-rise ratio and span length of the arch structure. It was confirmed that the earth pressure generated in the arch structure using the optimal soft zone selected by the numerical analysis was reduced by an average of 78%. In this study, the effect of EPS Geofoam on soil pressure reduction and its applicability to underground arch structures will provide an economical and conservative way to design underground structures and will help to increase the usability of deep underground space.

A numerical study on effects of thermal buoyance force on number of jet fans for smoke control (도로터널 화재시 열부력이 제연용 제트팬 댓수에 미치는 영향에 대한 해석적 연구)

  • Yoo, Ji-Oh;Shin, Hyun-Jun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.15 no.3
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    • pp.301-310
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    • 2013
  • Jet fans are installed in road tunnels in order to maintain critical velocity when fire occurs. Generally the number of jet fans against fire are calculated by considering critical velocity and flow resistance by wall friction, vehicle drag force, thermal buoyance force and natural wind. In domestic case, thermal buoyance force is not considered in estimating the number of jet fans. So, in this study, we investigated the pressure loss due to the thermal buoyance force induced by tunnel air temperature rise and the impact of thermal buoyance force on the number of jet fans by the numerical fire simulation for the tunnel length(500, 750, 1000, 1500, 2000, 3500m) and grade (-1.0, -1.5, -2.0%). Considering the thermal buoyance force, number of jet fans have to be increased. Especially in the case of 100MW of heat release rate, the pressure loss due to thermal buoyance force exceed the maximum pressure loss due to vehicle drag resistance, so it is analyzed that number of 2~11 jet fans are needed additionally than current design criteria. Thus, in case of estimating the number of jet fans, it must be considered of thermal buoyance force induced tunnel air temperature rise by fire.

A study on the optimization technique for the plan of slope reinforcement arrangement of soil-nailing in tunnel portal area (터널 갱구사면 쏘일네일링 보강배치계획을 위한 최적화기법 연구)

  • Kim, Byung-Chan;Moon, Hyun-Koo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.6
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    • pp.569-579
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    • 2016
  • In order to ensure the stability of tunnel portal slope, reinforcement method such as anchors, soil nails and rock bolts have been used in Korea. When selecting slope reinforcement methods in tunnel portal area such as reinforcement arrangement and length, trial and error method can be very time-consuming and it was also not easy to verify the selection of an optimum condition. In this study, using the FISH language embedded in the finite difference code FLAC3D program, the optimization technique was developed with the Differential Evolution Algorithm (DEA). After building a database on the soil nailing method in tunnel portal area, this system can be selected to an optimum arrangement plan based on the factor of safety through the FLAC3D analysis. Through the results of numerical analysis, it was confirmed that the number of analysis was decreased by about 8 times when DEA based optimization technique was used compared to the full combination (FC). In case of the design of slope reinforcement in tunnel portal area, if this built-system is used, it is expected that the selection of an optimum arrangement plan can be relatively easier.

Review of the installable area of multi-utility tunnel using feasibility assessment indexes (타당성 평가지표를 활용한 터널식 공동구 설치가능지역 검토)

  • Oh, Won-Joon.;Jin, Kyu-Nam.;Na, Gwi-Tae.;Cho, Choong-Yeun.;Sim, Young-Jong.
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.6
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    • pp.795-810
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    • 2019
  • In this paper, The study was conducted on the method to roughly determine the area and length of the multi-utility tunnel before the planning and design phase of the multi-utility tunnel construction. For this purpose, four feasibility indexes were used: traffic density, population density, disaster prevention index (number of workers), and urbanization rate, which reflect the regional characteristics. The installation criteria were set in consideration of the average value and minimum value of the feasibility indexes for the tunnel type among areas that can be installed in the multi-utility tunnel of Seoul. The analysis area included 200 areas based on 14 zones. The results of the analysis based on the minimum value of feasibility indexes indicated that the tunnel type of multi-utility tunnel is suitable for 39 areas with high traffic volume and population. On the other hand, the 'gun' area, etc., has a wider population than the 'si' and 'gu', suggesting that it is not suitable to install multi-utility tunnel. In addition, it can be seen that the larger the index value centered on the minimum value of each index, the smaller the tunnel type of multi-utility tunnel installation area.

Effect of Partial Replacement of Soybean Meal with Palm Kernel Meal and Copra Meal on Growth Performance, Nutrient Digestibility and Carcass Characteristics of Finishing Pigs

  • Kim, B.G.;Lee, J.H.;Jung, H.J.;Han, Y.K.;Park, K.M.;Han, In K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.14 no.6
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    • pp.821-830
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    • 2001
  • To study the effects of partial replacement of soybean meal (SBM) with palm kernel meal (PKM) and copra meal (CM) on growth performance, nutrient digestibility and carcass characteristics in finishing pigs, a total of 150 crossbred pigs (Landrace$\times$Duroc$\times$Yorkshire; average $52.11{\pm}1.08kg$ body weight) were alloted to five treatments, in a randomized block design. The treatments included 1) Control: without PKM or CM, 2) PKM2: 2% of palm kernel meal, 3) PKM4: 4% palm kernel meal, 4) CM2: 2% of copra meal, 5) CM4: 4% of copra meal. During the early finishing period (52~74 kg), growth performance was better in CM diets than in PKM diets or control diet, and in overall period (74~100 was lower (p<0.05) in PKM4 diet than the other diets. Nutrient digestibilies of PKM or CM substituted diets showed the tendency to be lower than those of control diet. In the early finishing period, total amino acid digestibilities of PKM and CM diets had the tendency to be lower than control diet, and in the late finishing period, they were lower (p<0.05) than control diet. Carcass length was longer (p<0.05) in the pigs fed 2% CM than in the pigs fed 4% PKM diet, but other carcass characteristics were not different among treatments. Although the dietary C14:0 content affected (p<0.05) on the C14:0 content in the carcass, the inclusion of PKM or CM in the diet did not affect the total saturated fatty acids and unsaturated fatty acids in the backfat of finishing pigs. Although it was not significant, supplementation of CM at the 2% and 4% of control group tended to decrease feed cost per kg weight gain by 2.89 to 1.42%, respectively. In conclusion, copra meal can be a valuable source of protein in the diet for finishing pigs and may replace other protein sources in pig diets to a considerable extent.

Influence of metabolizable energy on histology of liver and duodenal villus, microflora, heat shock protein gene in duck under heat stress (대사에너지가 열 스트레스에 노출된 오리의 간, 십이지장 융모, 미생물, 유전자 조절에 미치는 영향)

  • Shin, Jong-Suh;Yang, Boo-Keun;Park, Byung-Sung
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.3
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    • pp.613-622
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    • 2017
  • The object of this study was to determine the influence of dietary metabolic energy (ME) on ..... A total of 240 meat ducks Cherry valley (Anas platyrhynchos) were assigned into four treatment groups with a randomized block design for 42 days. The four treatments were: ME 2900 kcal/kg, ME 3000 kcal/kg, ME 3100 kcal/kg, and ME 3200 kcal/kg. There was no difference in liver tissue among the treatments. The duodenal villi and crypt depth length decreased by 10.58% in 2900 compared with ME 3000, but there was no difference between 3100 and 3200. Counts of caecal Latobacillus decreased by 9.47% in 2900 compared to ME 3000, but increased by 2.52 and 3.24% in 3100 and 3200, respectively. Total aerobic bacteria, E. coli and Coliform bacteria were increased by 2900 when compared to ME 3000, but there was no difference between 3100 and 3200. HSP $90-{\alpha}$ among the heat shock proteins (HSPs)-mRNA in the liver was reduced by 48.60% in 2900 compared to ME 3000, while 3100 and 3200 showed no difference or increased.

The Effect of Protein Source and Formaldehyde Treatment on Growth and Carcass Composition of Awassi Lambs

  • Abdullah, A.Y.;Awawdeh, F.T.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.8
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    • pp.1080-1087
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    • 2004
  • A trial with twenty-four newly weaned Awassi lambs (initial body weight=21.5$\pm$0.8 kg) was conducted using a 3$\times$2 factorial design to study the effect of feeding three sources of protein supplements (soybean meal (SBM), sunflower seed meal (SSM), and cottonseed meal (CSM)), either untreated or formaldehyde-treated on the growth performance and carcass traits of Awassi lambs. Lambs were randomly assigned to one of the six diets (4 lambs/treatment diet) and were individually fed for a period of 107 days. Experimental diets were isonitrogenous and isocaloric. Final live weight and average daily gain (ADG) were affected by both source of protein and formaldehyde treatment (undegradable protein). Lambs fed untreated diets had better (p<0.01) daily gain compared to those fed formaldehyde-treated diets. Similarly total feed intake per animal was significantly (p<0.05) affected by protein source and formaldehyde treatment. Formaldehyde treatment caused a significant decrease (p<0.01) in feed intake compared to lambs fed untreated diets. Feed requirement per unit of gain was not affected by formaldehyde treatment during all periods of the experiment except for the second period (the second 28 day period), whereby untreated SBM, SSM and CSM had better feed conversion ratio (FCR) than the treated groups. Source of protein had a moderate effect (p<0.10) on FCR but had a significant effect (p<0.05) on hot and cold carcass weight, digestive tract empty weight and liver weight, with lambs fed SBM having higher values than lambs fed SSM and CSM diets. Supplementation with undegradable protein had a significant effect (p<0.05) on dressing-out percentage (p<0.05), final live weight, and hot and cold carcass weight (p<0.01). The lower values pertain to lambs fed treated diets compared to lambs fed untreated diets. In general, there were no significant differences among all carcass linear dimensions, carcass cut weights and dissected loin tissue weights for both treatments (protein source and formaldehyde treatment). Supplementation with undegradable protein but not the source of protein resulted in significantly higher dissected leg total bone weight (p<0.05), tibia and femur weight (p<0.05), and femur length (p<0.01) at the same carcass weight. Results suggest that the treatment of SBM, SSM and CSM with formaldehyde did not improve efficiency of feed utilization, lamb performance or carcass traits and that the SBM diet resulted in an increase in lamb performance compared to other experimental diets.

The Effect of Pre-wilting and Incorporation of Maize Meal on the Fermentation of Bana Grass Silage

  • Manyawu, G.J.;Sibanda, S.;Mutisi, C.;Chakoma, I.C.;Ndiweni, P.N.B.
    • Asian-Australasian Journal of Animal Sciences
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    • v.16 no.6
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    • pp.843-851
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    • 2003
  • An experiment was conducted to investigate the effects of pre-wilting Bana grass (Pennisetum purpureum x P. americanum) herbage under sunny conditions for 0, 6, 18, 24, 32 and 48 h and ensiling it with maize meal. Four levels of maize meal(viz., 0, 5, 10 and 15% on fresh weight (Fw) basis) were tested. The experiment had a split-plot design. Wilting increased the concentration of water soluble carbohydrates (WSC) significantly (p<0.001) on a Fw basis, although there were no significant changes on DM basis. Unwilted grass contained $36.1g{\cdot}WSC{\cdot}kg^{-1}{\cdot}Fw$ ($127.6g{\cdot}kg^{-1}{\cdot}DM$) and this increased to $64.1g{\cdot}WSC{\cdot}kg^{-1}{\cdot}Fw$ ($116.7g{\cdot}kg^{-1}{\cdot}DM$) after 48 h of pre-wilting. Wilting also increased the DM content of herbage significantly (p>0.001) from 250 to $620g{\cdot}kg^{-1}$, between 0 and 48 h respectively. The concentration of fermentation end-products decreased (except butyric acid) and pH increased when the period of wilting increased, indicating that fermentation was restricted. In particular, lactic acid content declined from 50.8 to $26.2g{\cdot}kg^{-1}{\cdot}DM$ (p<0.01) and the residual WSC contents of silage increased from 2.7 with fresh herbage to $18.1g{\cdot}kg^{-1}{\cdot}DM$ with 48 h of wilting (p<0.001). Rapid wilting for 24 h, to a DM of $450g{\cdot}kg^{-1}$ was optimum since important increases in pH, residual WSC and DMD occurred at this level of wilting. Acetic acid, butyric acid and ammoniacal-N contents were lowest with 24 h of wilting. There were no significant interactions between length of wilting and the incorporation of maize meal. Wilting had a greater influence on fermentation than the incorporation of maize meal. Addition of maize meal facilitated fermentation by increasing forage DM content and reducing effluent production. In addition, the maize meal increased DMD. It was concluded that maize meal should generally be incorporated at a level of 5% on fresh weight basis.

A Study on the Design of Rotary Mower and Its Utilization. (Rotary Mower의 제작과 그 이용에 관한 연구)

  • 최규홍
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.17 no.4
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    • pp.3897-3920
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    • 1975
  • Since the most of Korean dairy and cattle raising farms are too small to introduce western mechanized farming, it is necessary to develope small size equipments. This study has been carried to develop a rotary mower as on attachment of 8 to 10 horse powertiller which is widely spread in rural area. It will not ony be helpfull for the farmers to harvesting hay grass but also desirable to increase the power tiller utility. The protto type rotary mower designed through the fundamental investigations, has been modified and improved through the field trials, and a series of field tests has been carried to investigate its performance and economic feasibility comparing with existing vailable harvesting equipments. The results are as follows; 1. To increase the stability, two guide wheels are attached to both side of the protto type rotary mower. 2. To prevent the clinging of tall grasses, the vertical driving shafts are covered with cylindrical protectors. 3. The cutting height is adjustable in 8 steps from 2.5 to 20 centimeters by changing the length of guide wheel legs. 4. The practical Critical cutting speed were always higher than theoretical value in both case of single cutting blade and three when the cutting depth was 25 millimeter. 5. The peripheral speed of cutting blade was varied in response to the change of engine speed, mean while the peripheral speed was adequate as it was changhed from 25 to 35 meter per second when the power tiller is operated in proper working ground speed. 6. The time requirement to harvest 10 a were 88.7, 54.6 and 41.4 minutes for the first, second and third stage of ground speed respectively, and because of the difficulty of delivery, it was observed that operating with fourth stage of ground speed was not recomanendable when the grass height is taller than 90 centimeters. 7. The performance of rotary mower were 1.1-1.7, 1.4-4.0, 3.8-11.8 and 7.4-22.0 times of reciprocating mower, portable disc type cutter, hay scythe and ordinary sickle respectively. 8. When the slope exceeds, 20 degree the downward harvesting operation was impossible because of the excessive front end weight, while less than 5 degree of land slope did not effect in field operation. 9. Increased traveling spee caused higher cutting height and slight cutting failure, but seems not to effect to the gross yield, and the efficiency of cutting width were from 83 to 94 precent. 10. Tn rank of economy were rotary mower (3,2 stage operation), reciprocating mower, hay scythe, portable disc type cutter and sickle in order when the annul operation exdeeds 100 hours. From the above results, it is convinced that the protto type rotary mower is good enough to the livestock farmers as a hay harvesting equipment because of its economy, hardiness in operating and its out standing performance and hopefully it will contribute to the extension of Korean livestock farming.

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Median Control Chart for Nonnormally Distributed Processes (비정규분포공정에서 매디안특수관리도의 모형설계와 적용연구)

  • 신용백
    • Journal of the Korean Professional Engineers Association
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    • v.20 no.3
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    • pp.15-25
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    • 1987
  • Statistical control charts are useful tools to monitor and control the manufacturing processes and are widely used in most Korean industries. Many Korean companies, however, do not always obtain desired results from the traditional control charts by Shewhart such as the X-chart, X-chart, X-chart, etc. This is partly because the quality charterstics of the process are not distributed normally but are skewed due to the intermittent production, small lot size, etc. In Shewhart X-chart, which is the most widely used one in Korea, such skewed distributions make the plots to be inclined below or above the central line or outside the control limits although no assignable causes can be found. To overcome such shortcomings in nonnormally distributed processes, a distribution-free type of confidence interval can be used, which should be based on order statistics. This thesis is concerned with the design of control chart based on a sample median which is easy to use in practical situation and therefore properties for nonnormal distributions may be easily analyzed. Control limits and central lines are given for tile more famous nonnormal distributions, such as Gamma, Beta, Lognormal, Weibull, Pareto, Truncated-normal distributions. Robustness of the proposed median control chart is compared with that of the X-chart, the former tends to be superior to the latter as the probability distribution of the process becomes more skewed. The average run length to detect the assignable cause is also compared when the process has a Normal or a Gamma distribution for which the properties of X are easy to verify, the proposed chart is slightly worse than the X-chart for the normally distributed product but much better for Gamma-distributed products. Average Run Lengths of the other distributions are also computed. To use the proposed control chart, the probability distribution of the process should be known or estimated. If it is not possible, the results of comparison of the robustness force us to use the proposed median control chart based on a normal distribution. To estimate the distribution of the process, Sturge's formula is used to graph the histogram and the method of probability plotting, $X^2$-goodness of fit test and Kolmogorov-Smirnov test, are discussed with real case examples. A comparison of the propose4 median chart and the X chart was also performed with these examples and the median chart turned out to be superior to the X-chart.

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