Preparation of SiO2/PEG Shear Thickening System by Centrifugal Dispersion

2012 ◽  
Vol 560-561 ◽  
pp. 586-590 ◽  
Author(s):  
Biao Yang ◽  
Sheng Wang ◽  
Guo Zhi Xu ◽  
Fei Xin
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
High Speed ◽  
Rotation Speed ◽  
Loss Modulus ◽  
Shear Thickening ◽  
Angular Frequency ◽  
Revolution Speed ◽  
Centrifugal Dispersion ◽  
The Revolution

The nano-SiO2/polyethylene glycol (PEG) dispersion system was prepared by centrifugal mixing, and its rheological properties were investigated. The results showed the revolution and rotation speed during the centrifugal mixing have a significant effect on the rheological properties of SiO2/PEG system. When the revolution speed of the centrifugal mixer was fixed at a high speed of 1200rpm, the shear thickening effect of SiO2/PEG was gradually increased with the decrease of rotation speed, and the maximum viscosity (η) of 12340 mPa•s appeared at the rotation speed of 200 rpm. At the low revolution speed of 700 rpm, the increase of the rotation speed significantly enhanced the shear thickening effect. When the rotation speed was 700rpm, the maximum viscosity was up to 86130mPa s. In steady state experiments, the systems show a shear-thinning property under low shear rate. When the shear rate exceeded a critical value (γ= 24.92 s-1), the viscosity first increased, and then decreased sharply. In the dynamic experiments, with the increase of angular frequency (ω), the loss modulus (G″) also increased and the systems behaved as a shear-thickening fluid.

Rheological properties of cholesteric liquid crystals as lubricant additives

2019 ◽  
Vol 33 (05) ◽  
pp. 1950014 ◽  
Author(s):  
A. Bindu Madhavi ◽  
S. Sreehari Sastry
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Loss Modulus ◽  
Flow Behavior ◽  
Lubricant Additives ◽  
Rheological Parameters ◽  
Practical Applications ◽  
Phase Transition Temperatures ◽  
Frequency Independent ◽  
Temperature Shear

Rheological properties of Cholesteryl n-valerate, Cholesteryl decanoate and Cholesteryl myristate which are esters of cholesterol have been studied. Phase transition temperatures and rheological parameters such as viscosity, elastic modulus G[Formula: see text], loss modulus G[Formula: see text] as functions of temperature, shear rate and time are investigated. In frequency sweep test, a higher transition crossover region has occurred for Cholesteryl myristate, whereas for Cholesteryl n-valerate a frequency-independent plateau prevailed for both the moduli. The occurrence of blue phase in Cholesteryl decanoate during temperature sweep measurements is an indication for the rheological support. The results for steady state have informed that cholesteric esters are having non-Newtonian flow behavior in their respective cholesteric phases. The power-law model has explained well the shear rate dependence of shear stress. A few practical applications of these esters as lubricant additives are discussed, too.

scholarly journals Study on Rheological Properties of Nanofluids

2021 ◽  
Vol 2132 (1) ◽  
pp. 012049
Author(s):  
Yan-qing Bian ◽  
Pu-cheng Wu ◽  
Jing Hao ◽  
Quan Shi ◽  
Guo-wei Qin
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Oil And Gas ◽  
Loss Modulus ◽  
Production Capacity ◽  
Tight Gas ◽  
Water Control ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Tight Gas Reservoir

Abstract Based on the previous research on the rheological properties of nanofluids by many scholars at home and abroad, to solve the problem that the viscosity of conventional polymer water control agents is large and cannot meet the demand for increasing production capacity in the process of tight gas reservoir exploitation, this paper takes self-made nanofluids as the research object, tests the rheological properties of self-made nanofluids by rheological experiment, and systematically studies the effects of concentration, temperature and shear action on the viscosity of nanofluids, and the dynamic viscoelasticity and thixotropy of nanofluids were discussed. The results show that the rheological type of nanofluid belongs to power-law fluid, but it is related to the shear rate. The viscosity of nanofluids increases with the increase of concentration; when the temperature increases, the viscosity of nanofluids decreases and the fluidity increases; under the shear action, the viscosity of nanofluid changes very little and has good shear resistance; the dynamic viscoelastic test shows that the storage modulus G´ of the nanofluid is larger than the loss modulus G”, showing elastic characteristics; the thixotropy test shows that when the shear rate is accelerated, the viscosity decreases with time, and when the shear rate is slowed down, the viscosity recovers rapidly with time, which has good thixotropy. The research results provide an important theoretical basis for further research on the application of nanomaterials in tight oil and gas reservoirs.

scholarly journals PENGARUH DIOCTYL ADIPATE TERHADAP SIFAT RHEOLOGIKAL HTPB TERPLASTISISASI (EFFECT OF DIOCTYL ADIPATE ON THE RHEOLOGICAL PROPERTIES OF PLASTICIZED HTPB)

2019 ◽  
Vol 16 (2) ◽  
pp. 139
Author(s):  
Afni Restasari ◽  
Luthfia Hajar Abdillah ◽  
Rika Suwana Budi ◽  
Kendra Hartaya
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Shear Thickening ◽  
Dioctyl Adipate

Pengembangan pengetahuan terhadap sifat rheologikal isian cair dari propelan berguna untuk mendapatkan sifat slurry yang optimum. Pengembangan ini dapat dimulai dari campuran HTPB-DOA sehingga penelitian ini bertujuan untuk mengetahui pengaruh DOA terhadap sifat rheologikal HTPB-DOA yang meliputi sifat alir terhadap shear rate, viskositas dan viskositas saat zero shear rate. Dalam metodenya, DOA divariasi 0, 5, 10, 15 dan 20% dan dicampur dengan HTPB. Sifat rheologikal dipahami dengan mengukur viskositasnya pada kecepatan putar 0,5; 1; 1,5; 2; 2,5; 3; 4 dengan spindel tipe 2 dari viskometer Brookfield dan menganalisa grafik shear stress vs shear rate serta viskositas vs shear rate. Berdasarkan analisa tersebut, diketahui bahwa campuran HTPB-DOA bersifat shear thickening. Semakin banyak DOA yang ditambahkan, semakin rendah viskositas campuran, semakin rendah nilai viskositas pada zero shear rate dan semakin kuat sifat shear thickening dari campuran.

scholarly journals The Rheological Studies on Poly(vinyl) Alcohol-Based Hydrogel Magnetorheological Plastomer

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2332
Author(s):  
Norhiwani Mohd Hapipi ◽  
Saiful Amri Mazlan ◽  
U. Ubaidillah ◽  
Koji Homma ◽  
Siti Aishah Abdul Aziz ◽  
...  
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Crosslinking Agent ◽  
Shear Thickening ◽  
Artificial Muscle ◽  
High Energy ◽  
Poly Vinyl Alcohol ◽  
Biomedical Sensors ◽  
Wide Range ◽  
Soft Actuators

The freezing–thawing method has been commonly used in the preparation of polyvinyl alcohol hydrogel magnetorheological plastomer (PVA HMRP). However, this method is complex and time consuming as it requires high energy consumption and precise temperature control. In this study, PVA HMRP was prepared using a chemically crosslinked method, where borax is used as crosslinking agent capable of changing the rheological properties of the material. Three samples of PVA HMRP with various contents of carbonyl iron particles (CIPs) (50, 60, and 70 wt.%) were used to investigate their rheological properties in both steady shear and dynamic oscillation modes. Results showed the occurrence of shear thickening behaviour at low shear rate (γ > 1 s−1), where the viscosity increased with the increased of shear rate. Moreover, the storage modulus of the samples also increased increasing the oscillation frequency from 0.1 to 100 Hz. Interestingly, the samples with 50, 60 70 wt.% of CIPs produced large relative magnetorheological (MR) effects at 4916%, 6165%, and 10,794%, respectively. Therefore, the inclusion of borax to the PVA HMRP can offer solutions for a wide range of applications, especially in artificial muscle, soft actuators, and biomedical sensors.

Influence of Temperature and Shear Rate on Rheological Properties of CTAC/NaSal Aqueous Solution

2019 ◽  
Vol 12 (4) ◽  
pp. 296-311
Author(s):  
Mingjun Pang ◽  
Chengcheng Xie
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Shear Viscosity ◽  
Chemical Engineering ◽  
Sodium Salicylate ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Power Law Function ◽  
Cetyltrimethyl Ammonium ◽  
Increasing Temperature

Background: It is very important for understanding the turbulence drag-reducing mechanism and for improving product quality in the fields of pharmaceutical and chemical engineering to deeply investigate the rheological properties of surfactants solutions. Methods: The rheological properties of Cationic surfactant (Cetyltrimethyl Ammonium Chloride)/Sodium salicylate were measured and analyzed with the MCR302 rheometer. Results: The present results show that the shear viscosity of CTAC/NaSal solution with the exception of 0.9375mmol·L-1 can show the Newtonian characteristic, the shear-thickening, the shear-thinning and the stable shear properties with changing shear time. The induction time increases with a shear rate as a power law function relation tind=aγb. Conclusion: The shear viscosity of the CTAC/NaSal solution can be divided into three regions with shear rate, and its flow curve conforms to a linear function in the logarithmic coordinate. When the concentration and the shear rate are relatively high, the viscosity curve of the CTAC/NaSal solution appears "platform" at the high temperature. When the shear rate is greater than 90s-1, the shear viscosity only appears shear thinning with increasing temperature.

Rheological Properties of Urea-CaLS Mixture for Urea Fertilizer Granulation

2013 ◽  
Vol 701 ◽  
pp. 329-332
Author(s):  
Jariah Mohamad Juoi ◽  
Farahani Irna Nazari ◽  
Nona Merry Merpati Mitan ◽  
Azizah Shaaban
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Newtonian Fluid ◽  
Parallel Plate ◽  
Shear Thickening ◽  
Urea Solution ◽  
Content Increase ◽  
Granulation Process ◽  
Viscosity Behavior ◽  
Thickening Behavior

The rheological properties of feedstock for granulation process are important in controlling the parameters throughout the process. This study identifies the type of fluid that mixtures of Urea and Calcium Lignosulfonates (CaLS) possessed through the viscosity profiles using a parallel plate rheometer. The viscosity behavior of mixtures with varied weight percentages (wt %) of CaLS in urea solution were analysed. Results identified that the mixtures show shear thickening behavior of non-Newtonian fluid. It is also observed that the increases of CaLS content increase the viscosity of the mixtures. Moreover, the mixture with 50 % CaLS addition is found not suitable for further investigation as its viscosity is too high (3.450-6.773 Pa.s at zero shear rate) compared to molten urea (0.002 Pa.s).

Effect of Addition of Antioxidant Flaxseed Polypeptide on the Rheological Properties of Native Maize Starch

2017 ◽  
Vol 13 (9) ◽  
Author(s):  
Yi Liu ◽  
Jie Ma ◽  
Dong Li ◽  
Li-jun Wang ◽  
Benu Adhikari ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Loss Modulus ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Angular Frequency ◽  
Protein Isolate ◽  
Maize Starch ◽  
Steady Shear Flow ◽  
Dpph Radical Scavenging ◽  
Controlled Hydrolysis

AbstractEffects of adding antioxidant flaxseed peptides (FP) on rheological properties of native maize starch (NMS) were investigated using temperature sweep and frequency sweep tests. The NMS concentration of 15 % (w/w) and FP concentrations of 0.2–1.0 % (w/w) were used. The FP samples were prepared by controlled hydrolysis flaxseed protein isolate with pepsin. The highest DPPH radical scavenging activity (53.25 %) was achieved at 22 % of hydrolysis. The onset gelatinization temperature (Tonset) increased from 67°C to 76°C when the 1 % FP was present in the NMS–FP mixture. The storage modulus (G′) decreased significantly in the presence and increased in concentration of FP. The variation ofG′and loss modulus (G″) of NMS–FP mixtures with angular frequency was fitted well (R2>0.97) Power law type models. The consistency coefficient (K′andK″) decreased in the presence and increased in the concentration of FP. While then′increased with the presence FP, then″decreased. The NMS–FP mixtures produced physical gels (G′>G″). NMS-FP mixtures showed non-Newtonian shear thinning behavior in steady shear flow.

scholarly journals Tuning Rheological Performance of Silica Concentrated Shear Thickening Fluid by Using Graphene Oxide

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Wenchao Huang ◽  
Yanzhe Wu ◽  
Ling Qiu ◽  
Cunku Dong ◽  
Jie Ding ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Shear Rate ◽  
Storage Modulus ◽  
Colloidal Silica ◽  
Loss Modulus ◽  
Shear Thickening ◽  
Light Weight ◽  
Critical Shear Rate ◽  
Shear Thickening Fluid ◽  
Significant Change

The addition of a small amount of graphene oxide into a traditional colloidal silica-based shear thickening fluid (STF) can lead to a significant change in viscosity, critical shear rate, storage modulus, and loss modulus of STF. This finding provides an effective way to prepare stronger and light-weight STFs.

scholarly journals Using Coupled Rheometer-FBRM to Study Rheological Properties and Microstructure of Cemented Paste Backfill

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Hongjiang Wang ◽  
Liuhua Yang ◽  
Hong Li ◽  
Xu Zhou ◽  
Xiaotian Wang
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Yield Stress ◽  
Rheological Behavior ◽  
Shear Thickening ◽  
Threshold Value ◽  
Rheological Parameters ◽  
Cemented Paste Backfill ◽  
Reflectance Measurement ◽  
Paste Backfill

Rheological properties, such as the yield stress, viscosity, and thixotropy, are related to the microstructure of cemented paste backfill (CPB). To highlight the relationship, two instruments were combined to measure the changes in the microstructure and the rheological properties of CPB simultaneously. In this way, the particle/agglomerate size distribution characterized by the focused beam reflectance measurement (FBRM) and the rheological factors measured by the rheometers could be directly linked. The results show that when under shearing, the intrinsic network structure of CPB responds to the shear-induced stresses with the interference of interparticle forces, leading to changes in the rheological behavior. Shear thinning can be found in CPB suspensions with a microstructure that is either loose interconnection or random. With an increase in the shear rate, random collisions among particles become organized in the flow, lowering the yield stress and viscosity. However, when the shear rate exceeds a certain threshold value, the rheological parameters change as a result of shear thickening. The results of this study contribute to better understanding of the complex rheological behavior of CPB.

scholarly journals Investigação do comportamento viscoelástico de amostras de licor negro oriundas do processo de polpação Kraft da Cenibra-MG à 25 oc

2021 ◽  
Vol 3 (4) ◽  
pp. 2411-2425
Author(s):  
Ângelo M. L. Denadai ◽  
Euler T. Dos Santos ◽  
Humberto L. Dos Santos ◽  
José M. Q. Moreira ◽  
Fernando C. De Oliveira ◽  
...  
Keyword(s):  
Shear Rate ◽  
Yield Stress ◽  
Loss Modulus ◽  
Viscoelastic Behavior ◽  
Shear Thickening ◽  
Complex Viscosity ◽  
Kraft Pulping ◽  
Chemical Recovery ◽  
Molecular Fragmentation ◽  
Black Liquors

RESUMO O comportamento viscoelástico dos licores negros de eucalipto (LN) do processo de polpação Kraft da CENIBRA foi avaliado a 25 oC, na ausência (LNSC) e na presença (LNCC) de cinzas da ebulição da recuperação química, que são geralmente misturadas com licores negros para melhorar a eficiência da recuperação química. As amostras foram tosquiadas em campos rotativos e oscilatórios, mostrando os comportamentos de cisalhamento e cisalhamento dependentes da taxa de cisalhamento aplicada. A viscosidade complexa - *, o módulo de armazenamento e perda - G' e G'', e a tensão de rendimento 0 para LNSC foram todos muito superiores ao LNCC, provavelmente devido à fragmentação molecular causada pela adição de cinzas.   ABSTRACT The viscoelastic behavior of eucalyptus black liquors (LN) from CENIBRA Kraft pulping process was evaluated at 25 oC, in absence (LNSC) and in presence (LNCC) of ash from chemical recovery boiling, which are usually mixed with black liquors to improve the efficiency of chemical recovery. The samples were sheared upon rotational and oscillatory fields, showing booth shear-thickening and shear-thinning behaviors dependent of applied shear rate. The complex viscosity – h*, storage and loss modulus – G’ and G’’, and yield stress s0 for LNSC were all very higher than LNCC, probably due the molecular fragmentation caused by addition of ashes.

Sign in / Sign up

Export Citation Format

Share Document