• Title/Summary/Keyword: relative height difference

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Effect of Sowing Date on Growth Characteristics and Dry Matter Yield of Alfalfa in a Dry Paddy Field

  • Lee, Bae Hun;Lee, Ki Won;Kim, Ji Hye;Lee, Se Young;Chang, Hyoung Ki;Park, Hyung Soo
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.42 no.3
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    • pp.169-175
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    • 2022
  • This study aimed to examine the changes in dry matter yield and growth characteristics of alfalfa (Medicago sativa L.) in response to variations in sowing dates during the autumn season of 2021-22 in a dry paddy field of Chilbo-myeon, Jeongeup-si, Jeollabuk-do. Treatments comprised four sowing dates at 10-day intervals, i.e., October 8, October 18, October 28, and November 8, 2021. The winter survival rate of alfalfa showed a significant difference between different treatments but was at a satisfactory level for all (p<0.05). The winter survival rate for the fourth sowing date, a month later than the first sowing date, was approximately 11.7% lower than that for the first sowing date. The plant height ranged between 82.3-93.1 cm and 60.5-63.7 cm at the first and second harvest, respectively, smaller at the second harvest than at the first harvest. The total dry matter yield of alfalfa was the highest at 13,316 kg/ha for the first sowing date, and the later the sowing date, the lower the dry matter yield. The protein content of alfalfa ranged between 13.6-17.3% in the first harvest, lower than the standard alfalfa protein content of 20% or more. In relative feed value, the first sowing (Oct. 8) was the most significantly higher in the first harvest (p<0.05). These results suggest that the early and mid-October sowing dates are optimum for sowing alfalfa during autumn and result in improved plant growth, dry matter yield, protein content, and winter survival compared to those at later sowing dates. Therefore, dry paddy fields can be safely employed for alfalfa cultivation with sowing dates in early and mid-October during autumn.

Analysis of Compression and Cushioning Behavior for Specific Molded Pulp Cushion

  • Jongmin Park;Gihyeong Im;Kyungseon Choi;Eunyoung Kim;Hyunmo Jung
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.30 no.1
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    • pp.53-62
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    • 2024
  • Molded pulp products has become more attractive than traditional materials such as expanded polystyrene foam (EPS) owing to low-priced recycled paper, environmental benefits such as biodegradability, and low production cost. In this study, various design factors regarding compression and cushioning characteristics of the molded pulp cushion with truncated pyramid-shaped structural units were analyzed using a test specimen with multiple structural units. The adopted structural factors were the geometric shape, wall thickness, and depth of the structural unit. The relative humidity was set at two levels. We derived the cushion curve model of the target molded pulp cushion using the stress-energy methodology. The coefficient of determination was approximately 0.8, which was lower than that for EPS (0.98). The cushioning performance of the molded pulp cushion was affected more by the structural factors of the structural unit than by the material characteristics. Repeated impacts, higher static stress, and drop height decreased the cushioning performance. Its compression behavior was investigated in four stages: elastic, first buckling, sub-buckling, and densification. It had greater rigidity during initial deformation stages; then, during plastic deformation, the rigidity was greatly reduced. The compression behavior was influenced by structural factors such as the geometric shape and depth of the structural unit and environmental conditions, rather than material properties. The biggest difference in the compression and cushioning characteristics of molded pulp cushion compared to EPS is that it is greatly affected by structural factors, and in addition, strength and resilience are expected to decrease due to humidity and repetitive loads, so future research is needed.

A Study on the Physical Growth and Health Status in University Students (일부(一部) 대학생(大學生) 신체발육(身體發育) 및 건강상태(健康狀態)에 관(關)한 조사(調査))

  • Kwon, E-Hyock;Cha, Chul-Hwan
    • Journal of Preventive Medicine and Public Health
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    • v.1 no.1
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    • pp.67-78
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    • 1968
  • For the purpose of ascertaining the status of physical growth and health status of the University students, a intensive survey was conducted by the authors towards a total of 2,638(male; 2,228, female; 410) who passed the written entrance examination at the Seoul National University. The items included the measurements on physical growth, various physical indixes, visual acuity, tuberculosis and dental status. The findings and results can be summarized as follows: 1. Physical Growth No significant difference was found in the physical growth between classes(literature and science) and by ages. In males, the means of body height, body weight, chest-girth and sittingheight were $168.0{\pm}5.07cm,\;55.7{\pm}5.71kg,\;85.8{\pm}4.4cm\;and\;91.5{\pm}2.21cm$, respectively. In females, these were $157.4{\pm}4.57\;cm,\;00.4{\pm}5.75kg,\;80.3{\pm}4.51cm\;and\;86.1{\pm}3.30cm$, respectively. Basing on the above measurements several physical indixes were calculated as follows ; Relative body weight 33.15 in males and 32.02 in females. Relative chest-girth 51.07 and 51.01, relative sitting-height 54.46 and 54.70 $R\ddot{o}hrer$ index 1.00 and 1.02, Kaup index 1.97 and 2.04, Vervaeck index 83.63 and 83.03, and Pelidisi index 89.94 and 92.45. 2. Visual Acuity Among the students of science classes those of 0.8 and below in vision on left and right occupied 46.4% and 45.0%, those of 0.6 and below 39.1% and 41.2%, respectively. Among the students of literature classes those of 0.8 and below occupied 46.3% and 42.9%, and those of 0.6 and below occupied 41.4% and 39.0, respectively. In males those of 0.8 and below occupied 46.8% and 44.5% and 0.6 and below occupied 41.9% and 39.7%, while in females 0.8 and below occupied 43.9%, and 42.4%, and 0.6 and below occupied 38.3% and 37.3%, respectively. In males those of 0.8 and below in corrected vision occupied 12.1% and 10.3%, while in females 12.9% and 12.2%, respectively. More students of abnormal vision were found among science classes and the proportions of corrected vision were 38.9% and 37.4% in males, and 33.9% and 33.2% in females, respectively. 3. Tuberculosis Among the total, 55 students were diagnosed as tuberculosis, of whom 50 were minimal cases, 2 were moderately advanced cases and 3 were far advanced cases. 4. Dental Status Among the total, 81.2% were of decayed teeth, 20.8% filled, 9.5% missed, 5.0% extraction needed, 9.1% sunplatinum bridges, 3.3% golden bridges and 5.5% golden inlay. Regarding tartar on teeth moderate, heavy and light grades occupied 49.5%, 29.7% and 20.3%, respectively and 0.8% had none. 5. Comprehensive evaluation According to criteria 4 grades were applied to comprehensive evaluation as follows : A...excellent in physical status B...with some physical defects but no difficulties in study C...need treatment D...need treatiment and rest Out of the total, A grade occupied 21.6%, B 76.2% and C. and D 2.2.

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The Analysis of Amplitude and Phase Image for Acoustic Microscope Using Quadrature Technique (쿼드러춰 방식에 의한 초음파현미경의 진폭과 위상영상 분석)

  • Kim, Hyun;Jun, Kye-Suk
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.3
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    • pp.55-61
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    • 1999
  • In this study, we have constructed the acoustic microscope using quadrature technique and analyzed the relative variation of image intensity and the quality of image by reconstructing the amplitude and phase image for surface defects with tiny hight variation. In this experiment, we have constructed the scanning acoustic microscope using the focused transducer with 3㎒ center frequency and the quadrature detector. And we have fabricated aluminum samples with round defects whose depth is different and reconstructed the amplitude and phase images for the samples. One sample has round defects with 2㎜ diameter and 100㎛ depth and the other has round defects with 4㎜ diameter and 5㎜ depth. In the result of line scanning for the sample with 100㎛ round defects, it has been shown that the variation rate of amplitude image intensity is 7% and the variation rate of phase image intensity is 89%. The phase image has better contrast than amplitude image for the sample. In contrast to this, the amplitude image has better contrast than phase image for the sample with 5㎜ depth's defects. Accordingly there is big difference between amplitude image and phase image for depth variation of defects whose boundary is 1 wavelength. Consequently the acoustic microscope using quadrature detector can be evaluated efficiently more than using envelope detector, for detecting defects which have height variation less than 1 wavelength. And also the phase image and the amplitude image can be used for detecting defects of tiny height variation with complimentary relation.

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Effect of Tillage System and Fertilizer Type on the Forage Yield and Quality of Italian Ryegrass (경운방법 및 비료종류가 이탈리안 라이그라스의 사초수량 및 품질에 미치는 영향)

  • Kim, Jong-Duk;Abuel, Shwin J.;Jeon, Gyeong-Hyeop;Kwon, Chan-Ho
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.29 no.4
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    • pp.313-320
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    • 2009
  • This experiment was conducted to evaluate the effect of tillage system and fertilizer type on the forage yield and quality of Italian ryegrass. This experiment was a $2{\times}2$ factorial arrangement for two tillage systems (tillage and no-tillage) and two fertilizer type (chemical and manure compost). The plant height, dry matter (DM) content, DM yield, TDN (total digestible nutrients) yield, and CP (crude protein) yield have significant differences in tillage system of Italian ryegrass. Italian ryegrass cultivated with tillage (plow and rotary till) had lower plant height, DM yield, TDN yield and CP yield than no-tillage, while its DM content showed the opposite results. However, there were no significant differences in the results on fertilizer types. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents were significantly higher in no-tillage compared to tillage. However, there was no significant difference in CP content on tillage system. TDN and relative feed value (RFV) were higher in tillage than no-tillage system (p<0.01). The TDN content was lower when using manure as fertilizer. No significant effects were observed for NDF and RFV in fertilizer type of Italian ryegrass. Based on the results of this study, tillage system and fertilizer type affected forage quality as well as forage yield. Forage yield of no-tillage was higher compared to tillage.

Characteristics of Biodegradable Films and Their Effects on Soybean Growth

  • Ye Geon Kim;Hyo Jin Lee;Do Jin Lee;Yong In Kuk
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2022.10a
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    • pp.50-50
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    • 2022
  • Recently, the use of mulching film has increased in soybean cultivation. Polyethylene (PE) films and biodegradable films (BF) have the advantages of improving soil moisture retention, geothermal maintenance, and CO2 maintenance as well providing weed control. Furthermore, BFs are a material that can compensate for the shortcomings of PE because it has the ability to decompose naturally by soil microorganisms, sunlight, and geothermal heat. Many researches have been carrying out studies regarding the development of BFs for these very reasons. This study was conducted better understand which films are optimal for soybean cultivation after evaluations of soybean growth and film characteristics of various BFs. BFs Farmsbio (Farm Hannong), Heulgro Film (Sejin Bio), Vonto Film (Eco-Hansung), two unnamed biodegradable films (Seojin Bio and Taesung), and a PE film were used in this study. For the control plots, no mulching was used. Experimental fields were fertilized according to conventional cultivation methods, tilled, and then covered with either BFs or PE films. After 1 week, soybean (cv. Daechan) seeds were seeded. Germination rate and plant height were measured at weekly intervals after seeding. In addition, pH, EC, and decomposition and light transmittance levels of films were measured during the experimental period. Daily average temperatures and relative humidity in soils was measured during the experimental period. There was no significant difference in germination rates and plant height in both crops grown with BFs and PE films, but crops grown in the control plot had significantly lower germination rates and growth. Soil pH was not significantly different regardless of treatments (BF, PE, and non-mulching) at 14, 28, and 42 days after seeding. In general, the EC contents in the control plots was lower than in crops grown using BFs and PE films. With the exception of some BFs, light transmittance and decomposition levels of films did not, in general, increase up to 70 days after soybean seeding. Since this study is ongoing, we are continually investigating these parameters. The average daily moisture in soil was higher in crops grown with BFs and PE films than in the control plot. However, the daily average soil temperature was not consistent regardless of treatments. Therefore, the BFs used in this study can be used without negative impacts on soybean growth.

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An Analysis of the Characteristics of Aerosol Light Scattering Coefficients at Seoul and Baengnyeongdo (서울과 백령도의 에어로솔 산란계수 특성 분석)

  • Eun, Seung-Hee;Nam, Hyoung-Gu;Kim, Byung-Gon;Park, Jin-Soo;Ahn, Jun-Young;Lee, Seok-Jo
    • Journal of Korean Society for Atmospheric Environment
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    • v.29 no.3
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    • pp.264-274
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    • 2013
  • This study investigates long-term trends and characteristics of aerosol light scattering coefficient at Seoul and Baengnyeongdo in order to understand aerosol optical and radiative properties around Korea. The analysis period is limited to one year of 2011. First, the aerosol scattering coefficients (${\sigma}_{sp}$) of both sites show strong linear dependence on the $PM_{2.5}$ mass concentrations with significant correlations between both. Further, correlations and sensitivity between ${\sigma}_{sp}$ and $PM_{2.5}$ increase with relative humidity, implying both relationships are strongly dependent upon moisture amounts in the atmosphere. This study applied 3-step careful quality control procedures to the analysis of ${\sigma}_{sp}$ for the insurance of data confidence. For the relationship analysis of extinction coefficients (${\sigma}_{ext}$) to visibility and aerosol optical depth, ${\sigma}_{sp}$ observed at 3 p.m. have been used with help of aerosol absorption coefficients (${\sigma}_{ap}$) in order to remove its dependence upon relative humidity, and also those of rainy period have been excluded. As expected, ${\sigma}_{ext}$ estimated are inversely proportional to visibility observation by eye. Finally, aerosol extinction coefficients have been vertically integrated with an assumption of nearly well-mixed within an e-folding height to determine aerosol optical depth, and compared with those retrieved from sunphotometer. The results show a reasonable agreement in spite of an inherent difference of each definition. We expect these findings would help to eventually understand aerosol radiative forcing and its effect on the regional climate change around Korea.

By-product of Tropical Vermicelli Waste as a Novel Alternative Feedstuff in Broiler Diets

  • Rungcharoen, P.;Therdthai, N.;Dhamvithee, P.;Attamangkune, S.;Ruangpanit, Y.;Ferket, P.R.;Amornthewaphat, N.
    • Asian-Australasian Journal of Animal Sciences
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    • v.26 no.12
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    • pp.1732-1741
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    • 2013
  • Two experiments were conducted to determine physical and chemical properties of vermicelli waste (VW) and effect of VW inclusion levels on growth performance of broilers. In experiment 1, VW samples were randomly collected from vermicelli industry in Thailand to analyze nutritional composition. Vermicelli waste contained 9.96% moisture, 12.06% CP, 32.30% crude fiber (CF), and 0.57% ether extract (EE), as DM basis. The ratio of insoluble:soluble non-starch polysaccharide (NSP) was 43.4:8.9. A total of 120 chicks (6 pens per treatment and 10 chicks per pen) were fed a corn-soybean meal-based diet or 20% VW substituted diet to determine the apparent metabolizable energy corrected for nitrogen retention ($AME_n$) of VW. The $AME_n$ of VW was $1,844.7{\pm}130.71$ kcal/kg. In experiment 2, a total of 1,200 chicks were randomly allotted to 1 of 4 dietary treatments for 42-d growth assay. There were 300 chicks with 6 pens per treatment and 50 chicks per pen. The dietary treatments contained 0%, 5%, 10%, or 15% VW, respectively. All diets were formulated to be isocaloric and isonitrogenous. From 0 to 18 d of age chicks fed VW diets had higher (p<0.001) feed conversion ratio (FCR) compared with those fed the control diet. No difference was observed during grower and finisher phase (19 to 42 d). Chicks fed VW diets had lower relative weight of abdominal fat (p<0.001) but higher relative weight of gizzard (p<0.05) than those of chicks fed the control diet. Increasing VW inclusion levels increased ileal digesta viscosity (p<0.05) and intestinal villus height of chicks (p<0.001). For apparent total tract digestibility assay, there were 4 metabolic cages of 6 chicks that were fed experimental treatment diets (the same as in the growth assay) in a 10-d total excreta collection. Increasing VW inclusion levels linearly decreased (p<0.05) apparent total tract digestibility of DM and CF.

Development of Korean Geoid Model and Verification of its Precision (우리나라 지오이드 모델 구축 및 정밀도 검증)

  • Lee, Jisun;Kwon, Jay Hyoun;Baek, Kyeong Min;Moon, Jiyeong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.30 no.5
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    • pp.493-500
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    • 2012
  • The previous geoid model developed in early 2000s shows 14cm level of precision due to the problems on distribution, and quality of the land gravity and GPS/Leveling data. From 2007, the new land and airborne gravity data as well as GPS/Leveling data having high quality and regular distribution has been obtained. In 2011, a new gravimetric geoid model has been constructed with precision of 5.29cm which was improved about 27% comparing to the previous model. However, much more land gravity data has been collected at the control point, bench marks and triangulation points since 2010. Also, GPS/Leveling data having 10km spacing over whole country has been obtained through the project which is for the construction of new control points. In this study, new gravimetric geoid has been calculated based on the all available gravity data up to present. The geoid height shows the range from 18.05m to 32.70m over whole country and its precision is 5.76cm. The degree of fit and precision of hybrid geoid model are 3.60cm and 4.06cm, respectively. At the end, 3.35cm of the relative precision in 15km baseline has been calculated to confirm its practical usage. Especially, it has been founded that regional bias occurred at the Kangwon and coastal area due to problems on the leveling data. Also, some inland points show inconsistent large difference which needs to be verified by analyzing the unified control points results.

The Effect of Shear Direction on the Behavior of the Post-earthquake Settlement of GBFS (반복전단 방향의 영향에 따른 GBFS의 지진후 침하 거동)

  • Baek, Won-Jin;Hiroshi, Matsuda;Park, Kyung-Hwan;Kim, Jin-Young
    • Journal of the Korean Geotechnical Society
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    • v.26 no.3
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    • pp.5-12
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    • 2010
  • In this study, in order to clarify the effect of the direction of cyclic shear on the post-earthquake settlement the multi-directional shear tests were carried out for Toyoura Japan standard sand, Genkai natural sand, Kaolinite and the Granulated Blast Furnace Slag (GBFS). The diameter and the height of the specimen are 75 mm and 20 mm, respectively. In a series of tests, the number of strain cycles was adjusted as n=5, 20, 30, 100, 200 and the shear strain amplitudes were varied from 0.1% to 1.0%. The relative densities of each samples were also adjusted as Dr=50, 60 and 70%. From the test results for Toyoura sand and GBFS, it is clarified that the post-earthquake settlement is relatively large at the small relative density and becomes large with the shear strain amplitude. When the influence of difference on the direction of cyclic shear decreases, the post-earthquake settlement strain for Toyoura sand is converged to a constant value, but the GBFS increases with the number of strain cycles. In addition, the post-earthquake settlement is in the order of Kaolinite > Toyoura sand > Genkai sand > GBFS.