Earticle

This paper describes the automatic control of disc type rheometer. This developed device will able to provide flexibility to operator for testing of rubber. The operator has to just enter the duration of test and parameters through man machine interface. All the operations will occur automatically without any intervention in a prescribed sequence stored in programmable logic controller (PLC). This developed apparatus is useful not only for testing purpose, but it can be used for research for other types of materials also. With this state of art apparatus one can control the quality of rubber for various applications such as tyre industry. Also this would help to increase the production of rubber as automatic control comes which reduces the test duration to few minutes only.

본 연구에서는 유변물성측정기를 이용하여 HPMC 첨가량, 물 양, HPMC 분자량, 셀룰로오스 에테르 치환체 및 치환도가 쌀 반죽의 압축 및 접착 특성에 미치는 영향에 대해 살펴보았다. HPMC 첨가량이 증가함에 따라 접착강도는 꾸준히 증가하였으나, 압축강도는 2% HPMC 첨가량에서 최대 강도를 보였다. HPMC의 분자량이 증가하거나, 물 양이 감소할수록 쌀 반죽의 압축강도 및 접착강도가 증가하는 결과를 보였다. 이들 인자 외에도, 셀룰로오스 에테르의 치환체 및 치환도도 쌀 반죽의 압축강도 및 접착 강도를 결정하는 중요한 인자임을 확인하였다.

The present study examined the effect of cellulose ether on the compression and adhesion characteristics of rice dough using a rheometer. When increasing the amount of hydroxypropyl methylcellulose (HPMC), the adhesion strength consistently increased. However, the compression strength of the rice dough was the highest with 2% HPMC. When increasing the molecular weight and decreasing the water content, the compression and adhesion strength of the rice dough were both increased. Furthermore, the substitution type and degree of cellulose ether were also found to be key factors determining the compression and adhesion strength of the rice dough.

본 연구는 산수유 분말을 첨가 양갱의 항산화 효과 및 관능적 특성을 연구하였다. 총 폴리페놀과 DPPH 라디 칼 소거능 연구 결과에서는 양갱에 산수유 분말 첨가량이 추가됨에 따라 높은 항산화 효과를 나타내었다. 품질특성 연구로 색도는 결과에서 L값은 산수유 분말 첨가량이 증가됨에 따라 감소하였고, a값, b값은 증가하는 경향을 보였 다. 조직감 측정 결과 견고성과 응집성, 탄력성과 씹힘성에서 산수유 분말 첨가량이 증가됨에 따라 낮아지는 경향을 보였다. 관능검사는 색의 경우 7% 첨가군이 가장 높았고, 맛은 5% 첨가군이 높았으며, 향과 부드러운 정도는 9%, 가장 높았으며, 전반적인 기호도 결과에서는 5% 첨가군에서 7.45로 가장 높게 평가되었다. 따라서 우리는 산수유 분 말을 첨가하여 양갱을 제조 할 경우 5% 첨가 또는 7% 첨가량이 합리적이라는 결론을 얻었다.

This study investigated the antioxidant effect and sensory characteristics of yanggaeng containing Corni fructus powder. The results of the total polyphenol and DPPH radical scavenging activity study showed that the antioxidant effect was higher as the amount of Corni fructus powder added to the yanggaeng increased. In the quality characteristic study, the color L value decreased as the amount of Corni fructus powder added increased, while the a and b values s h owed an increasing trend. As a result of the rheometer measurement, hardness, Cohesiveness, Springiness, and chewiness tended to decrease as the amount of Corni fructus powder added increased. The sensory evaluation, the color was the highest in the 7% addition group, the taste was the highest in the 5% addition group, the flavor and softness were the highest at 9%, and in the overall acceptability results, the 5% addition group was evaluated as the highest at 7.45. Therefore, we concluded that adding 5% or 7% of Corni fructus powder to make Yanggaeng is reasonable.

Plasticity is the ability of clay to respond to pressure with a continuous and permanent change of shape in any direction without breaking apart, and hold that shape when released. In this work, the effect of water content and aging period on the plasticity of porcelain clay was evaluated using the capillary rheometer to measure the flow rate and the shear stress. The shear stress of porcelain clay was slightly increased with increasing the aging period, indicating that the plasticity of porcelain clay was influenced by an organic content. It was also observed that the water content in the porcelain clay had a great influence on the plasticity of porcelain clay. The shear stress with water content of 21 wt% was sharply increased with increasing shear rate, but the shear stresses with water contents of 24 and 27 wt% is gently incremented.

For highly viscous fluids that slip in parallel sliding plate rheometers, we want to use a slightly converging flow to suppress this wall slip. In this work, we first attack the steady shear flow of a highly viscous Newtonian fluid between two gently converging plates with no slip boundaries using the equation of motion in cylindrical coordinates, which yields no analytical solution. Then we treat the same problem using the lubrication approximation in Cartesian coordinates to yield exact, explicit solutions for dimensionless velocity, pressure and shear stress. This work deepens our understanding of a drag flow through a gently converging slit of arbitrary convergence angle. We also employ the corotational Maxwell model to explore the role of viscoelasticity in this converging shear flow. We then compare these analytical solutions to finite element calculations for both Newtonian and corotational Maxwell cases. A worked example for determining the Newtonian viscosity using a converging shear rheometer is also included. With this work, we provide the framework for exploring other constitutive equations or other boundary conditions in future work. Our results can also be used to design the linear bearings used for the parallel sliding plate rheometer (SPR). This work can also be used to evaluate the error in the shear stress that is caused by bearing misalignment and specify the parallelism tolerance for the linear bearings incorporated into a SPR.

Objective: The purpose of this study was to investigate the viscoelastic properties related to handling characteristics of composite resins, Methods: A custom designed vertical oscillation rheometer (VOR) was used for rheological measurements of composites. The VOR consists of three parts: (1) a measuring unit, (2) a deformation induction unit and (3) a force detecting unit, Two medium viscous composites, Z100 and Z250 and two packable composites, P60 and SureFil were tested. The viscoelastic material function, including complex modulus $E^{*}$ and phase angle ${\delta}$, were measured. A dynamic oscillatory test was used to evaluate the storage modulus (E'), loss modulus (E") and loss tangent ($tan{\delta}$) of the composites as a function of frequency ($\omega$) from 0.1 to 20 Hz at $23^{\circ}C$. Results: The E' and E" increased with increasing frequency and showed differences in magnitude between brands. The $E^{*}s$ of composites at ${\omega}{\;}={\;}2{\;}Hz$, normalized to that of Z100, were 2.16 (Z250), 4,80 (P60) and 25.21 (SureFil). The magnitudes and patterns of the change of $tan{\delta}$ of composites with increasing frequency were significantly different between brands. The relationships between the complex modulus $E^{*}$, the phase angle ${\delta}$ and the frequency \omega were represented by frequency domain phasor form, $E^{*}{\;}(\omega){\;}={\;}E^{*}e^{i{\delta}}{\;}={\;}E^{*}{\angle}{\delta}$. Conclusions: The viscoelasticity of composites that influences handling characteristics is significant different between brands, The VOR is a relatively simple device for dynamic, mechanical analysis of high viscous dental composites. The locus of frequency domain phasor plots in a complex plane is a valuable method of representing the viscoelastic properties of composites.

알루미나 분말/(알루미나+결합체+가소제)의 비(X)와 결합체/(결합체+가소제)의 비(Y)를 각각 변화시켜 제조한 알루미나 그린 테이프의 complex modulus를 Micro Fourier Rheometer를 이용하여 측정하였다. X와 Y의 증가에 따라 Transfer function(TF) magnitude는 증가하고 Transfer function(TF) phase는 감소하는 경향을 보였으며 이로부터 X비와 Y비의 증가가 테이프의 탄성을 증가시켜는 요인임을 알 수 있었다. 온도가 증가함에 따라 알루미나 테이프의 TF magnitude는 작아지고 TF phase는 커지는 것으로부터 테이프의 점성이 증가함을 알 수 있었다. 특히 Y비에 따른 complex modulus의 변화는 유리전이온도와 관련이 있으며 변화값은 측정 조성 범위 내에서 X비에 의한 변화값보다 큼을 볼 수 있었다. complex modulus 측정을 통하여 알루미나 테이프의 성형이 가능하기 위해서는 TF phase 값이 17$^{\circ}$이상이어야 함을 유추할 수 있었다.

Alumina tapes, having various weight ratios of alumina powder/(alumina+binder+plasticizer), X, and binder / (binder+plsticizer), Y, were prepared and their complex modulus was measured using Micro Fourier Rheometer. As the X and Y ratios increased, Transfer function(TF) magnitude and Transfer function (TF) phase increased and decreased, respectively, indicating that the elastic modulus of the tapes depends on the weight ratios. The temperature dependence of the viscosity of the tapes was visualized by the decreased TF magnitude and the increased TF phase. The Y ratio dependence of the complex modulus related to the glass transition temperature of the tapes and the moduls change by the Y ratio was higher than that by the X ratio within the comperature of the tapes and the modulus changes by the Y ratio was higher than that by the X ratio within the composition range, investigated in the present study. The measurement of the complex modulus of the alumina tapes suggested that the TF phase should be higher that 17$^{\circ}$for the tapes to be utilized for 3-dimensional shaping.

본 연구에서는 직접 제작된 전도유체(electrorheological fluid)용 수직진동 rhemeter 기기상의 구조 해석 및 실험을 실시하였다. 수직진동 rheomether는 간단하게 제작이 가능하고, 고전압 발생장치를 연결하므로 전동유체의 점탄성 특성을 비교적 쉽게 측정할 수 있다. Rheometer의 구조적 변수와 측정된 힘, 변형 등을 이용하여 복소 점도(complex viscosity), 복소 전단 변형률(complex shear modulus), loss tangent 등의 선형 점탄성 물질 함수를 직접 계산할 수 있으며, corn starch를 polybutene/kerosene에 분산시킨 전동유체를 이용하여 전기장하의 점탄성을 측정하였다.

Power-law fluids exhibiting shear-thinning behavior frequently appear in food colloidal and emulsion systems. Because such fluids undergo both shear and extensional deformation, quantifying their extensional rheology is essential for understanding food flowability and sensory properties. In this study, the extensional rheological properties of tomato ketchup, a representative power-law fluid, were characterized using a Capillary Breakup Extensional Rheometer (CaBER). Experiments were performed under an acceleration a = 3 m/s² and a final aspect ratio Λ_f = 1.83, varying the initial stretching velocity. A stable passive stretching regime, allowing rheological analysis, appeared at speeds above 60 mm/s. The dimensionless filament diameter evolution of ketchup followed a power-law model whose index matched that obtained from steady-shear viscosity. The extensional viscosity decreased with increasing extensional rate following a power-law trend, consistent with the shear viscosity-shear rate relationship.

고무생산업체에서 생산된 고무는 레오미터 측정을 통해 품질 적합성 검사가 이루어진 후, 자동차 부품을 위한 2차 가공으로 이어진다. 그러나 레오미터 검사는 인간에 의해 진행되고 있으며, 숙련된 작업자에게 매우 의존적이라는 단점이 존재한다. 이러한 문제점을 해결하기 위해 본 논문에서는 딥러닝 기반 레오미터 품질 검사 시스템을 제안한다. 제안된 시스템은 레오미터의 시간적, 공간적 특성을 활용하기 위해 LSTM과 CNN을 조합하였고, 각 고무의 배합재료를 보조(Auxiliary) 데이터 입력으로 사용해 하나의 모델에서 다양한 고무 제품의 품질 적합성 검사가 가능하도록 구현하였다. 제안된 기법은 30,000개의 데이터셋으로 그 성능을 학습 및 검사하였으며, 평균 f1-점수를 0.9942 달성하여 그 우수성을 증명하였다.

Rubber produced by rubber companies is subjected to quality suitability inspection through rheometer test, followed by secondary processing for automobile parts. However, rheometer test is being conducted by humans and has the disadvantage of being very dependent on experts. In order to solve this problem, this paper proposes a deep learning-based rheometer quality inspection system. The proposed system combines LSTM(Long Short-Term Memory) and CNN(Convolutional Neural Network) to take advantage of temporal and spatial characteristics from the rheometer. Next, combination materials of each rubber was used as an auxiliary input to enable quality conformity inspection of various rubber products in one model. The proposed method examined its performance with 30,000 validation datasets. As a result, an F1-score of 0.9940 was achieved on average, and its excellence was proved.

Curing reaction was carried out with the acrylic resin (ACR) [n-butyl acrylate/atyrene/2-hydroxyethyl methacrylate/acetoacetoxyethyl methacrylate (AAEM)] synthesized before and a curing agent, hexamethoxymethylmelamine (HMMM). With rotational rheometer, the effect of catalysts on curing rate of acrylic resin/melamine was examined. Among the four catalysts used, p-toluene sulfonic acid showed the highest reactivity, and the optimum amount of catalyst was 0.5 phr. It was observed that in the ACR/HMMM curing reaction, gelation point was lowered with the increasing the amount of AAEM and HMMM in the ACR.

Rheological properties of electrorheological(ER) fluids have been investigated by either steady-shear test or dynamic test. In this work, we studied rheological properties of polyaniline-silicone oil ER system through dynamci mechanical test using vertical oscillation rheometer(VOR) that is designed by our lab. It was then calibrated with Physcia rheometer using corn starch-polybutene(PB)/kerosene system. Data from VOR rwer quite reliable in a wide range of either strain or frequency. For amplitude sweep of polyaniline system, G's in linear region were slightly different with each otehr for the applied electric field, but the linear range was becoming larger as increasing elecric field. From begining of the nonlinear region, the differences were becoming bigger and input strain wave began to distort.

Viscosity measurement and the flow behavior prediction of reinforced polymer melts have been considered crucial for quality consistency in commercial products where highly filled polymer composites are used. In this study, a slit-die rheometer mounted on an injection molding machine was employed to measure the shear viscosity of a reinforced polymer melt by monitoring the pressure drop in the slit and the ram movement for various melt temperatures and shear rates. Mold filling experiment was also conducted using an injection molding process with two plaque-shaped parts of different thicknesses. Polycarbonate with 40 weight % of glass fibers was investigated in the experiment. A comparative numerical simulation was conducted as well using the measured viscosity in the current study. The pressure drops from the simulation and the experiments were compared, which reveals that the viscosity measured using a slit-die rheometer is relatively accurate.

In this study, we prepared polypropylene (PP) blends with commercially available amphiphilic diblock copolymer poly(ethylene-block-ethylene oxide) (P(E-b-EO)). Selective surface enrichment of the diblock copolymer used was observed only on the PP blend extrudates which were prepared using capillary rheometer with different wall shear rates showing that flow processes play an enormous role in surface migration.

The control of the rheological properties of a fluid during processing is important and can determine the efficiency of the production in addition to the performance of the final product. The vast majority of process fluids are viscoelastic, hence an instrument that measures both the viscous and elastic properties of the material during processing would be of great practical use. However, most in-line instruments commercially available to date are only capable of measuring viscosity at a single shear rate. An in-line rheometer that measures both the viscous and elastic properties of fluids over a wide range of shear rates simultaneously has been described in a previous publication (Glasscock et at., 2003) in which the results of measurements on flowing sunflower oil were presented. Before this instrument can be used in an industrial situation, it must be demonstrated that the generated results are the same as, or bear some fixed relationship to, the results obtained by conventional off-line rheometers. To this end, the present investigation describes the measurements of a standard reference fluid, polyisobutylene dissolved in 2,6,10,14-tetramethylpentadecane, labelled SRM2490 by the National Institute of Standards and Technology (NIST) in the USA. The results obtained using the in-line rheometer show remarkably good correlation for viscosity, using a modified Cox­Merz rule, with the results supplied with the reference material from NIST.