Comparison of Grain Quality Traits between Japonica Rice Cultivars from Korea and Yunnan Province of China

Teng-Qiong Yu,Wenzhu Jiang,Tae-Ho Ham,추상호,Puji Lestari,이정희,Myeong-Ki Kim,Fu-Rong Xu,Longzhi Han,Lu-Yuan Dai,Hee-Jong Koh 한국작물학회 2008 Journal of crop science and biotechnology Vol.11 No.2

Improving eating quality is one of the most important objectives in japonica rice breeding programs in Yunnan Province of China. Eating quality and its relevant traits of nine Korean and 11 Yunnan rice cultivars were comparatively analyzed in this study. The grain shape of most Yunnan japonica rice cultivars have a relatively slender shape and are slightly larger than Korean rice cultivars. Palatability value of cooked rice of Yunnan rice cultivars was significantly lower, while the protein content of Yunnan rice cultivars was significantly higher than that of Korean cultivars. Peak viscosity and breakdown viscosity of the Yunnan rice cultivars were significantly lower, while setback viscosity of the Yunnan rice cultivars was significantly higher than in Korean rice cultivars. Palatability value of cooked rice was negatively correlated with protein content and setback viscosity but positively correlated with peak viscosity, breakdown viscosity, and cool paste viscosity. Through multiple linear regression analysis, an equation for estimating palatability value (PV) of cooked rice based on quality traits was generated as dependent only upon protein content (PC), PV=139.024-(10.865×PC) with an R² value of 0.822. The results suggest that reducing protein contents should be the major target in improving eating quality of Yunnan japonica rice cultivars through integrated approaches of both cultivar development and appropriate cultural practices. Genetic similarities among cultivars based on DNA markers which had been identified as associated with grain quality seemed not to be directly related to PV. Improving eating quality is one of the most important objectives in japonica rice breeding programs in Yunnan Province of China. Eating quality and its relevant traits of nine Korean and 11 Yunnan rice cultivars were comparatively analyzed in this study. The grain shape of most Yunnan japonica rice cultivars have a relatively slender shape and are slightly larger than Korean rice cultivars. Palatability value of cooked rice of Yunnan rice cultivars was significantly lower, while the protein content of Yunnan rice cultivars was significantly higher than that of Korean cultivars. Peak viscosity and breakdown viscosity of the Yunnan rice cultivars were significantly lower, while setback viscosity of the Yunnan rice cultivars was significantly higher than in Korean rice cultivars. Palatability value of cooked rice was negatively correlated with protein content and setback viscosity but positively correlated with peak viscosity, breakdown viscosity, and cool paste viscosity. Through multiple linear regression analysis, an equation for estimating palatability value (PV) of cooked rice based on quality traits was generated as dependent only upon protein content (PC), PV=139.024-(10.865×PC) with an R² value of 0.822. The results suggest that reducing protein contents should be the major target in improving eating quality of Yunnan japonica rice cultivars through integrated approaches of both cultivar development and appropriate cultural practices. Genetic similarities among cultivars based on DNA markers which had been identified as associated with grain quality seemed not to be directly related to PV.

Effect of viscosity-inducing factors on oxygen transfer in production culture of bacterial cellulose

SeongJun Kim,Hongxian Li,오일권,ChangDoo Kee,MyongJun Kim 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.6

Bacterial cellulose (BC) production culture requires high oxygen transfer rate (representatively kLa) at a low shear force. Considering that oxygen exhaustion is observed at the latter half of the exponential growth phase where BC production actually begins, it is highly probable that the drastic reduction of kLa (oxygen volumetric transfer coefficient)is caused by the drastic increase of the soluble and insoluble viscous materials. Therefore, we examined the apparent viscosity-inducing materials generated during BC culture and investigated their effects on kLa. Using the saccharified liquid from food waste as the culture medium, we discussed the relationship between the concentration of the generated solid matters, especially BC and the viscosity, the relationship between the BC concentration and kLa,and the correlation between the viscosity and kLa. The relationship between the solid matter (BC), which is the insoluble viscosity-inducing material, and kLa showed that the BC concentration and kLa were in exponentially reciprocal proportion with the linear regression equation. In case of using agar as the soluble viscosity-inducing material, the correlation between the viscosity and kLa showed that the viscosity depending on the agar concentration was in exponentially reciprocal proportion with kLa in both tap water and the saccharified liquid medium. The results indicated that the effect of the BC concentration on kLa was not great in the saccharified liquid medium. As the agar concentration increased in tap water and the saccharified liquid medium, the viscosity was increased and kLa was decreased gradually, showing a linear relation between the logarithm of the viscosity as agar and kLa. In conclusion, the effect of the soluble viscosity on kLa was greater than that of solid matter (BC). Also, it was suggested that the soluble viscosity-inducing matters like agar were rather more effective than kLa in BC production.

The complex viscosity of polymer carbon nanotubes nanocomposites as a function of networks properties

Yasser Zare,Vesna Mišković‑Stanković,Kyong Yop Rhee 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Cross model correlates the dynamic complex viscosity of polymer systems to zero complex viscosity, relaxation time and power-law index. However, this model disregards the growth of complex viscosity in nanocomposites containing filler networks, especially at low frequencies. The current paper develops the Cross model for complex viscosity of nanocomposites by yield stress as a function of the strength and density of networks. The predictions of the developed model are compared to the experimental results of fabricated samples containing poly(lactic acid), poly(ethylene oxide) and carbon nanotubes. The model’s parameters are calculated for the prepared samples, and their variations are explained. Additionally, the significances of all parameters on the complex viscosity are justified to approve the developed model. The developed model successfully estimates the complex viscosity, and the model’s parameters reasonably change for the samples. The stress at transition region between Newtonian and power-law behavior and the power-law index directly affects the complex viscosity. Moreover, the strength and density of networks positively control the yield stress and the complex viscosity of nanocomposites. The developed model can help to optimize the parameters controlling the complex viscosity in polymer nanocomposites.

이차전지 슬러리용 파일럿 점도 모니터링 시스템 개발 및 검증

유현동(Hyun Dong You),최현우(Hyeon Woo Choi),이병민(Byung Min Lee),김한성(Han Sung Kim),황욱렬(Wook Ryol Hwang) 대한기계학회 2024 大韓機械學會論文集B Vol.48 No.3

In the mixing process of lithium-ion secondary battery electrodes, rheological properties of anode and cathode slurries influence significantly the electrochemical and thermomechanical behaviors of the final electrode and, among others, the viscosity is the most important property. The slurry viscosity varies with shear rate and, therefore, the measurement of viscosity involves both the measurements of (representative) both shear rate and viscosity. In this study, we developed and validated a pilot-scale in-situ/on-line viscosity monitoring system through a pipe flow system, using the energy-dissipation-rate-based flow quantification technique, by determining the effective viscosity and effective shear rate from the information of the pressure drop and flow rate, respectively. The viscosity measurement results were validated through both numerical and experimental methods. The measured viscosity as a function of the effective shear rate had with less than 10.48% errors in comparison with the rheological data, once the optimized correction factor for the slurry was employed.

High-temperature viscosity analysis of aluminosilicate melts and the comparison to empirical models

고현석,Kim Myounguk,Park Sun-Min,Lim Hyung Mi 한국세라믹학회 2021 한국세라믹학회지 Vol.58 No.2

Understanding the high-temperature viscosity of aluminosilicate near liquid–solid transition is important in the metallurgical industry and fi berization processes, but the experimental determination of viscosity is time and cost consuming. To date, a number of viscosity models have been reported, yet their applicability at such temperature remains questionable. In this paper, the high-temperature viscosities of nine aluminosilicate compounds are measured by rheometer FRS 1600, which allows precise measurements under controlled conditions. Both rotational and oscillation modes are utilized to evaluate the shear viscosity and complex viscosity. The measured viscosities are then compared with empirical models in the literature. It is found that the Urbain model and FactSage simulation output reasonable prediction on viscosities for most of compositions, with an order of magnitude error. We also found none of the models showed a good agreement for Fe-rich multicomponent systems, even Kondratiev model of which Fe content was an important design factor. The results suggest that Urbain model and FactSage simulation are a fair choice for approximating the viscosities for aluminosilicate system (35–56 wt% SiO 2 , 11–20 wt% Al 2 O 3 , 6–37 wt% CaO, and 2–10 wt% MgO) at 1150–1400 °C, but the viscosity models have errors at given temperature range due to their limitation in design composition and temperature.

Conformations of gelatin in trivalent chromium salt solutions: Viscosity and dynamic light scattering study

Congde Qiao,Jianlong Zhang,Aiqun Kong 한국유변학회 2017 Korea-Australia rheology journal Vol.29 No.1

An investigation of the influences of pH, salt type, and salt concentration on the conformations of gelatin molecules in trivalent chromium salt solutions was performed by viscosity and dynamic light scattering (DLS) techniques. It was found that the viscosity behaviors as polyelectrolytes or polyampholytes depended on the charge distribution on the gelatin chains, which can be tuned by the value of pH of the gelatin solution. The intrinsic viscosity of gelatin in basic chromium sulfate aqueous solution at pH = 2.0 first decreased and then increased with increasing Cr(OH)SO4 concentration, while a monotonic decrease of the intrinsic viscosity of gelatin was observed in CrCl3 solution. However, the intrinsic viscosity of gelatin at pH = 5.0 was found to be increased first and then decreased with an increase in salt concentration in Cr(OH)SO4 solution, as well as in CrCl3 solution. We suggested that the observed viscosity behavior of gelatin in trivalent chromium salt solutions was attributed to the comprehensive effects of shielding, overcharging, and crosslinking (complexation) caused by the introduction of the different counterions. In addition, the average hydrodynamic radius (Rh) of gelatin molecules in various salt solutions was determined by DLS. It was found that the change trend of Rh with salt concentration was the same as the change of intrinsic viscosity. Based on the results of the viscosity and DLS, a possible mechanism for the conformational transition of gelatin chains with external conditions including pH, salt concentration, and salt type is proposed.

The complex viscosity of polymer carbon nanotubes nanocomposites as a function of networks properties

Zare Yasser,Mišković-Stanković Vesna,이경엽 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Cross model correlates the dynamic complex viscosity of polymer systems to zero complex viscosity, relaxation time and power-law index. However, this model disregards the growth of complex viscosity in nanocomposites containing filler networks, especially at low frequencies. The current paper develops the Cross model for complex viscosity of nanocomposites by yield stress as a function of the strength and density of networks. The predictions of the developed model are compared to the experimental results of fabricated samples containing poly(lactic acid), poly(ethylene oxide) and carbon nanotubes. The model’s parameters are calculated for the prepared samples, and their variations are explained. Additionally, the significances of all parameters on the complex viscosity are justified to approve the developed model. The developed model successfully estimates the complex viscosity, and the model’s parameters reasonably change for the samples. The stress at transition region between Newtonian and power-law behavior and the power-law index directly affects the complex viscosity. Moreover, the strength and density of networks positively control the yield stress and the complex viscosity of nanocomposites. The developed model can help to optimize the parameters controlling the complex viscosity in polymer nanocomposites.

Asymmetric cyanine as a far-red fluorescence probe for mitochondrial viscosity

Park, Sang Jun,Shin, Bong Ki,Lee, Hyo Won,Song, Ju Man,Je, Jong Tae,Kim, Hwan Myung Applied Science Publishers 2020 Dyes and pigments Vol.174 No.-

<P><B>Abstract</B></P> <P>Mitochondrial viscosity affects respiratory state and signal transduction. As a result, abnormal mitochondrial viscosity leads to diabetes, accelerated aging, insulin resistance, Alzheimer's disease, Parkinson's disease, and Huntington's disease. Previously reported probes for mitochondrial viscosity have absorption and emission wavelengths in the green to orange region and thus are hampered by interference with biomolecules. In addition, rotors with disubstituted double bonds have low photostability, due to photoisomerization. Here, we report a new far-red viscosity probe, <B>SFC-Cy007</B>, which has high photostability, due to a tetrasubstituted double bond. This probe was selectively located in the intracellular mitochondria and immediately responded to changes in mitochondrial viscosity via swelling and inflammatory responses. Furthermore, <B>SFC-Cy007</B> stained well at very low concentrations in the hippocampal tissue, allowing visual observation of viscosity distribution in hippocampal tissue for the first time.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Far-red fluorescence probe to detect of mitochondrial viscosity. </LI> <LI> Asymmetric cyanine as a molecular rotor with high photostability. </LI> <LI> Immediate response to changes in mitochondrial viscosity through swelling and inflammation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Modeling and optimization of dynamic viscosity of oil-based nanofluids containing alumina particles and carbon nanotubes by response surface methodology (RSM)

Mohammad Hemmat Esfe,Sayyid Majid Motallebi,Davood Toghraie 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.10

The dynamic viscosity of MWCNT-Al2O3 (40 : 60)/SAE50 nanofluid (NF) is investigated. NF viscosity modeling is also performed using the response surface methodology (RSM). Several different models are proposed, including modified and unmodified cubic, quartic and fifth models, and the best modeling is selected using the parameters R2, Adjusted R2, Predicted R2 and Square root of the residual mean square (Std. Dev.). The results show that the fifth-order model has values of 0.9997, 0.9997, 0.9996 and 2.39 for R2, Adjusted R2, Predicted R2 and Std. Dev. parameters, respectively, which indicates high accuracy of modeling. Using the perturbation diagram, it was found that among the parameters of temperature, solid volume fraction () and shear rate (), the temperature parameter has the greatest effect on the dynamic viscosity of NF. The trend of changes in viscosity also shows that  and  have little effect on viscosity. Due to the importance of low viscosity in fluid flow and pumping, the optimal values of NF viscosity are presented, including dynamic viscosity equal to 108.092 cP in  =0.063 and T=49.998 oC and  =7,866.7786 s1.

음식물류폐기물 수소 발효액의 유변학적 특성과 교반강도 고찰

김민균(Min-Gyun Kim),이모권(Mo-Kwon Lee),임성원(Seong-Won Im),신상룡(Sang-Ryong Shin),김동훈(Dong-Hoon Kim) 유기성자원학회 2017 유기물자원화 Vol.25 No.4

점도, 임펠러 종류, 소비전력 등에 의해 영향을 받는 생물학적 폐기물 처리시설 및 에너지 생산 플랜트에서 적절한 교반 시스템의 설계는 필수적이다. 본 연구에서는 적절한 교반 시스템의 설계를 위해 음식물류폐기물을 이용하여 다양한 조건(운전 pH 및 농도)에서의 수소발효 시 유변학적 특성의 변화를 조사한 후, 이를 기반으로 교반강도를 설계하였다. 운전 pH에 따른 수소발효 실험에서 수소전환율은 0.51~1.77 mol H 2 /mol hexose added 였고, 가장 높은 수소전환율은 운전 pH 5.5에서 나타났다. 발효액은 전단속도가 증가함에 따라 점도가 감소하는 Shear thinning 거동을 보였다. 탄수화물이 분해되면서 발효 이후 점도는 초기 점도보다 감소하는 경향을 보였으나, 운전 pH의 변화에 따른 발효액의 점도 변화는 크지 않았다. 탄수화물 농도 10~50 g Carbo. COD/L에서 수소전환율은 1.40~1.86 mol H 2 /mol hexose added 로 운전 pH 조건이 수소전환율에 미친 영향과 비교했을 때 큰 차이는 없었다. 발효액의 Zero viscosity와 Infinite viscosity는 탄수화물 농도에 따라 각각 10.4~346.2 mPa‧s와 1.7~5.3 mPa‧s로 나타났는데, 10 g Carbo. COD/L와 20 g Carbo. COD/L에서 발효액의 점도 값은 거의 차이가 없었다. 실험 결과에 기초하여 교반강도를 설계한 결과, 기질농도 30 g Carbo. COD/L의 수소발효 초기 및 발효 후 교반강도는 각각 26.0, 10.0 rpm으로 약 2.5배 정도의 교반강도를 줄임으로써 에너지를 절약할 수 있을 것으로 사료된다. The design of proper agitation system is requisite in biological waste treatment and energy generation plant, which is affected by viscosity, impeller types, and power consumption. In the present work, hydrogen fermentation of food waste was conducted at various operational pHs (4.5~6.5) and substrate concentrations (10~50 g Carbo. COD/L), and the viscosity of fermented broth was analyzed. The H 2 yield significantly varied from 0.51 to 1.77 mol H 2 /mol hexose added depending on the pH value, where the highest performance was achieved at pH 5.5. The viscosity gradually dropped with shear rate increase, indicating a shear thinning property. With the disintegration of carbohydrate, the viscosity dropped after fermentation, but it did not change depending on the operational pH. At the same pH level, the H 2 yield was not affected much, ranging 1.40~1.86 mol H 2 /mol hexose added at 10~50 g Carbo. COD/L. The zero viscosity and infinite viscosity of fermented broth increased with substrate concentrations, from 10.4 to 346.2 mPa‧s, and from 1.7 to 5.3 mPa‧s, respectively. There was little difference in the viscosity value of fermented broth at 10 and 20 g Carbo. COD/L. As a result of designing the agitation intensity based on the experimental results, it is expected that the agitation intensity can be reduced during hydrogen fermentation. The initial and final agitation intensity of 30 g Carbo. COD/L in hydrogen fermentation were 26.0 and 10.0 rpm, respectively. As fermentation went on, the viscosity gradually decreased, indicating that the power consumption for agitation of food waste can be reduced.