• 펄프종이기술
• /
• 제48권3호
• /
• pp.91-98
• /
• 2016

Linerboards have been produced by recycling recovered paper such as old corrugated containers(OCC). Usually linerboards produced during summer season show weak strength compared with those of produced during winter. In order to cope with the weak strength of linerboards produced during summer, and to confirm uniform quality, it is important to understand the seasonal effect on strength properties. Effect of pulping temperature of the OCC for linearboard production was investigated by controlling pulping temperatures at $18^{\circ}C$ and $51^{\circ}C$. Low pulping temperature ($18^{\circ}C$) caused more generation of fines in stock. Consequently retention and drainage of linerboard defibrated at high pulping temperature ($51^{\circ}C$) were better than those of $18^{\circ}C$. Strength properties of handsheet at low pulping temperature were higher than those of high pulping temperature and it could be confirmed that low pulping temperature during winter is one reason of seasonal variation of recycled linerboard strength. It is considered that surface modification of OCC fibers by harsh pulping action during winter caused increase of paper strength.

• 농업과학연구
• /
• 제46권3호
• /
• pp.461-469
• /
• 2019

The aim of this study was to analyze the contribution of carcass traits (backfat thickness, eye muscle area, carcass weight and marbling score) and the season at slaughter to the price (auction and market) using squared semi-partial correlation. The season at slaughter (summer expressed as season_2, autumn as season_3, and winter as season_4) were added into the estimation as dummy variables, and spring was set as a default variable. In this study, the carcass grades of 22,298 Hanwoo steers slaughtered from 2012 to 2017 were used to performmultiple regression analysis. The rankings of the contribution of the carcass traits and the seasons at slaughter to the auction prices were in the order of marbling score (68.63%), season_4 (11.88%), backfat thickness (10.45%), eye muscle area (6.11%), season_3 (2.19%), season_2 (0.45%) and carcass weight (0.28%). (R-square of the regression = 0.4101). The rankings of the contribution to the total prices were in the order of carcass weight (51.74%), marbling score (32.12%), season_4 (6.04%), backfat thickness (5.54%), eye muscle area (3.22%), season_3 (1.14%), and season_2 (0.19%). (R-Square of the regression = 0.6486). As a result, season_3 and season_4 had a negative effect on the auction price and total price. Because of seasonal event such as Korean Thanksgiving Day and Korean New Year's Day on season_3 and season_4, much supply was needed to meet the high demand. Thus, the seasonal effect at slaughter could be another factor to be cosideredin when considering of slaughter or breeding.

• Membrane and Water Treatment
• /
• 제10권5호
• /
• pp.339-352
• /
• 2019

Long term water quality change was analyzed to evaluate the effect of the Total Maximum Daily Load (TMDL) policy. A trend analysis was performed for biochemical oxygen demand (BOD) and total phosphorus (TP) concentrations data monitored at the outlets of the total 41 TMDL unit watersheds of the Nakdong River in the Republic of Korea. Because water quality data do not usually follow a normal distribution, a nonparametric statistical trend analysis method was used. The monthly mean values of BOD and TP for the period between 2004 and 2015 were analyzed by the seasonal Mann-Kendall test and the locally weighted scatterplot smoother (LOWESS). The TMDL policy effect on the water quality change of each unit watershed was analyzed together with the results of the trend analysis. From the seasonal Mann-Kendall test results, it was found that for BOD, 7.8 % of the 41 points showed downward trends, 26.8 % and the rest 65.9% showed upward and no trends. For TP, 51.2% showed no trends and the rest 48.8% showed downward trends. From the LOWESS analysis results, TP began to decrease in most of the unit watersheds from mid-2010s when intensive chemical treatment processes were introduced to existing wastewater treatment plants. Overall, for BOD, relatively more points were improved in the main stream compared to the points of the tributaries although overall trends were mostly no trend or upward. For TP, about half of the points were improved and the rest showed no trends.

• 한국가시화정보학회지
• /
• 제18권2호
• /
• pp.28-34
• /
• 2020

In this study, we numerically investigated the thermal stratification in solar seasonal thermal storage tanks. The vertical in/out flows were unsuitable for the thermal stratification in a large scale. The effect of an aspect ratio (AR) on the thermal stratification was investigated. When AR was less than 2, water adheres and flows along the upper wall due to buoyance and the surface effect. Thereafter, hot water flows down and a large scale vortex occurs in entire tank. For high AR, jet flows ejected from the inlet pipe impinges to the opposite wall and splits. The divided flows create two vortex flows in the upper and lower regions. These different flows strongly influence temperature and thermal stratification. The thermal stratification was evaluated in terms of the thermocline thickness and degree of stratification. Compared to ARs, the maximum degree of stratification was obtained with AR of 5 having the minimum thermocline thickness.

• 한국식품영양과학회지
• /
• 제25권3호
• /
• pp.519-522
• /
• 1996

From the leaves of Lindera sericea Bl., kaempferol-3,7-0-di-a-L-rhamnopyranoside was isolated and characterized by spectral data and acid hydrolysis. This compound is reported for the first time from this plant. The content of kaempferol glycoside was high in May and June, and low in the fall. And the methoanolic extract of title plant showed the inhibitory effect on carrageenin-induced edema.

• Asian-Australasian Journal of Animal Sciences
• /
• 제21권12호
• /
• pp.1779-1784
• /
• 2008

Seasonal changes in the concentration of free amino acids were determined monthly in plasma from the jugular blood of 50 thoroughbred racehorses that compete during the night between June and September and during the day between October and January. The concentration of most free amino acids remained relatively constant between June and January. However, those of glutamic acid, alanine, isoleucine and lysine tended to decrease and that of arginine (Arg) significantly decreased between July and September. The concentration of methionine (Met) gradually increased between June and September and significantly decreased thereafter. The concentration of 3-methylhistidine (3-MH) significantly increased between July and September and decreased thereafter. There were significant correlation between 3-MH and Arg. In conclusion, this study provided evidence of significant seasonal change in plasma 3-MH, Arg and Met of racehorses, and this was considered to relate to an environmental effect. Moreover, our study is the first to show 3-MH in plasma of racehorses affected by environmental change.

• 한국방재학회 논문집
• /
• 제1권2호
• /
• pp.93-101
• /
• 2001

본 연구에서는 계절에 따른 온도 변화를 고려한 건조수축의 예측모델을 제시하여, 실제구조물에서의 계절에 따른 온도변화에 대한 장기 거동 특성을 보다 향상된 방법으로 파악할 수 있는 방법을 제시하였다. 본 연구에서 사용된 건조수축 보정계수식은 계절에 따른 온도변화를 포함한 건조수축의 실제 실험적 데이터들을 사용하여 제안되었으며, FCM 교량의 장기 거동 조사는 현장에서 건조수축의 수치해석 결과를 적용할 수 있는지 없는지를 결정하기 위해 수행되었다. 본 연구에서 채택된 수치해석 방법은 실제 변형율과 차이가 발생하는 일반적인 방법과는 달리 실제 구조물의 거동특성을 매우 유사하게 모사할 수 있는 것으로 나타났다. 결과적으로 본 연구에서 제안된 방법은 FCM 교량의 장기 처짐에 대한 예측을 향상 시킬 것이다.

• 한국수산과학회지
• /
• 제36권5호
• /
• pp.474-479
• /
• 2003

The effect of season, life stages and harvesting sites on the yield and properties of agars extracted from Gracilaria verrucosa were determined. G. verrucosa were collected seasonally from November 2001 to August 2002 at Cheongsapo and Boryong, Korea. The plants were sorted Into the different life stages (tetrasporophytes and gametophytes) and dried at $60^{\circ}C.$ The yield, sulfate, protein, uronic acid and 3,6-anhydrogalactose of the agar were determined, and standard parameters of physical quality were measured. No differences were found in yield and properties of agars from the two different harvesting sites and from lift history phases. The yield of agar was maximum in summer $(17.3-20.0\%)$ and minimum in winter $(11.9-13.1\%).$ Maximum gel strength occurred in winter when the agar yield and sulfate content were low. Gel strength was negatively correlated with agar yleld. Seasonal variations in agar yield and its quality were discussed in a view to managing the exploitation of this resource.

• Journal of Microbiology and Biotechnology
• /
• 제24권7호
• /
• pp.921-924
• /
• 2014

C31G is a potent antimicrobial agent and can disrupt the microbial membrane by the alkyl portion of the molecule. The objective of this study was to evaluate the virucidal effectiveness of C31G and mouthrinse containing C31G (Sense-Time) on seasonal influenza viruses. Evaluation of the virucidal activity against influenza viruses was performed with end-point titration in 10-day-old chicken embryos and Madin-Darby canine kidney cells. In vitro studies demonstrated that C31G and Sense-Time inhibited the growth of seasonal influenza viruses even in the presence of 5% organic material. Gargling with C31G or Sense-Time would enhance oropharyngeal hygiene, which would be helpful for reducing influenza transmission.

• 한국환경보건학회지
• /
• 제26권2호
• /
• pp.41-48
• /
• 2000

This study has been carried out to determine the seasonal characteristics of concentration of various ionic (CI-, NO3-, SO42-, Na+, NH+, K+, Ca2+) and heavy metallic (Pb, Mn, Cu, Ni) species in Pusan from August 1997 to April 1998. The concentrations of CI-, Na+, K+ were higher during summer with 2.98 ${\mu}{\textrm}{m}$/㎥. Seasonal variation of total concentration of but the concentration of NH4+ was higher during winter with 2.46${\mu}{\textrm}{m}$/㎥. Seasonal variation of total concentration of heavy metals(Pb, Cu, Mn, Ni) were 186.0 ng/㎥ in summer, 222.6 ng/㎥ in autumn, and 135.83 ng/㎥ in winter. Over the seasons inspected, the concentration of Mn was higher in coarse particles than fine particles and concentration of Ni was higher in fine particles than coarse particles. during yellow sand period, the concentration of TSP was increased about two times than that of other period. SO42-, Ca2+ concentrations were higher than other ionic components because of soil particles. The concentration of Ni showed 94.62ng/㎥ was increased about 4~5 times than other period. Principal component of the yellow sand, SO42-, Ca2+ could be discreased by rainfall and washout effect of atmospheric aerosol was higher in coarse particles than fine particles. Results from PCA(principal component analysis) showed that major pollutant was NaCl by seasalt particulate and (NH4)2SO4.