scholarly journals Use of helical ribbon mixer for measurement of rheological properties of fruit pulps

2013 ◽  
Vol 19 (No. 4) ◽  
pp. 148-153 ◽  
Author(s):  
P. Novotná ◽  
A. Landfeld ◽  
K. Kýhos ◽  
M. Houška ◽  
J. Strohalm
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Flow Behaviour ◽  
Rotational Rheometer ◽  
Shear Rates ◽  
Coaxial Cylinders ◽  
Helical Ribbon ◽  
Flow Behaviour Index ◽  
Average Shear ◽  
Behaviour Index

Fruit pulps contain fine particles of the flesh of the original fruit that are suspended in the fruit juice. This suspension has a tendency to settling or separation during measurements of its rheological properties in the rotational rheometer with coaxial cylinders (especially if the greater gap is used). In this case the use of a mixer is convenient. The mixer can serve as a tool for measurement of rheological properties and at the same time it can prevent the settling and it is not sensitive to the occurrence of greater particles in the measured fluid. The helical ribbon mixer was used in this work for measurement of five samples of fruit pulp. The mixer was calibrated by the use of Newtonian fluid of known viscosity (honey). The radius of the inner cylinder of hypothetical rotational rheometer was predicted from the assumption that mixer and cylinder exhibit the same torque necessary for the rotation at the same rotational speed. The average shear rate in the mixed pulp was predicted by using the relation valid for power law fluids and rheometer with coaxial cylinders. The radius (where the average shear rate was calculated) was chosen by the requirement that the shear rate would be almost independent of changes in the flow behaviour index valid for measured pulps. Firstly the flow behaviour index was predicted as a slope of torque vs. rotational speed dependence in log-log co-ordinates. It was found that the flow behaviour index varies in the range 0.2–0.3. The radius was predicted from a graph where shear rates for 0.2 and 0.3 are the same. Then the average shear rates were calculated from rotational speeds for individual flow behaviour indexes. Rheological properties measured by using a mixer correspond to those measured with a rotational rheometer with coaxial cylinders satisfactorily only in the case that the creeping flow regime was kept in the mixed fluid. The fruit pulps are strongly non-Newtonian fluids with very low values of the flow behaviour index around 0.2.

The Influence of Sewage Fat Composition on Rheological Behavior of Metal Injection Moulding

2014 ◽  
Vol 660 ◽  
pp. 38-42 ◽  
Author(s):  
Azriszul Mohd Amin ◽  
Mohd Halim Irwan Ibrahim ◽  
Rosli Asmawi ◽  
Najwa Mustapha
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Injection Moulding ◽  
Rheological Characteristic ◽  
Flow Behaviour ◽  
Characteristic Analysis ◽  
Metal Injection Moulding ◽  
Flow Behaviour Index ◽  
Binder Ratio ◽  
Behaviour Index

Influence of sewage ratio or Fat Oil Grease (FOG) on the feedstock rheological characteristic for optimal binder formulation in metal injection moulding is evaluated besides Polypropylene (PP) as a backbone binder. Powder loading of 62% of water atomised SS316L being used here to determine the possibility of the best binder formulation which could be optimised for optimal powder loading base on rheological characteristic analysis. Two binder formulations of PP to SF being selected here are 60/40, 50/50 and 40/60 accordingly with the powder loading of 62% each binder formulation. The analysis will be base on viscosity, shear rate, temperature, activation energy, flow behaviour index and moldability index. It is found that from rheological result views, binder with composition of 60/40 and 50/50 exhibit pseudoplastic behaviour or shear thinning where the viscosity decrease with increasing shear rate. For 40/60 binder ratio is not suitable since the behaviour of the flow indicates dilatants behaviour. After considering all the criteria in terms of flow behaviour index, activation energy, viscosity and mouldability index, binder with ratio of 60/40 is evolve as a good selections.

scholarly journals Viscosity and biodiesel characteristics of wild Canarium schweinfurthii Engl. fruit oil  

2018 ◽  
Vol 64 (No. 4) ◽  
pp. 169-175
Author(s):  
Ehiem James Chinaka
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Medical Model ◽  
Temperature Stability ◽  
Oil Viscosity ◽  
Shear Rates ◽  
Flow Behaviour Index ◽  
Different Temperatures ◽  
Fruit Oil ◽  
Behaviour Index

The viscosity of two varieties of Canarium schweinfurthiiEngl. fruits oil (large and long) were studied at four different temperatures (30, 40, 50 and 60<sup>o</sup>C) and three shear rates (7.91, 15.82 and 39.54 s<sup>–1</sup>). SurgiFriend Medical (model NDJ-5S) viscometer was used to carry out the study. Biodiesel characteristics of the oil were also investigated. The results showed that variety had no effect (P &lt; 0.05) on the viscosity of Canarium schweinfurthii Engl. fruit while temperature had especially at 50<sup>o</sup>C and above. The shear rate of 15.82 s<sup>–1 </sup>(12 rps) gave the lowest oil viscosity for both varieties. The oil from large fruit had the best temperature stability, low percentage viscosity (6.33%) variation and least activation energy (796.51 J·mol<sup>–1</sup>·K<sup>–1</sup>) while long variety had best biodiesel characteristic for safe handling. Temperature had no significant (P &lt; 0.05) effect on the consistency coefficient (C) and flow behaviour index (n) of both varieties of Canarium schweinfurthii Engl. fruits oil. Besides, oil from both fruit varieties is Newtonian fluids.

scholarly journals Effect of Different Shear Rates on Particle Microstructure of Cementitious Materials in a Wide Gap Vane-in-cup Rheometer

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2035
Author(s):  
Mahmoud Eslami Pirharati ◽  
Hans-W. Krauss ◽  
Carsten Schilde ◽  
Dirk Lowke
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Cement Paste ◽  
Particle Agglomeration ◽  
Shear Rates ◽  
Average Shear ◽  
Local Shear ◽  
Wide Gap ◽  
Agglomeration State ◽  
Shear History

Rheological properties of cementitious suspensions are affected not only by their mixture composition but also by process-related factors such as shear history. To enable a model-based description, investigations were carried out on the effect of shear history (shear rate variation over time) on the cement paste agglomeration state. Therefore, a Focused Beam Reflectance Measurement (FBRM) system and a wide gap rheometer were coupled to study the relation between shear history and in-situ chord length distribution simultaneously, indicating particle agglomeration. Hence, the effect of average shear rates (resulting from the applied shear profile), as well as shear rate distribution within the gap (local shear rates) on the particle agglomeration state have been investigated. The rheological properties of cement paste were evaluated with the Reiner–Riwlin approach. Furthermore, the agglomeration state of the particles was compared for different average shear rates and local shear rates at various positions of the FBRM probe. The results show that the median chord length increases in all positions when the average shear rate is decreased, indicating increasing particle agglomeration. Moreover, due to variable local shear rates at different FBRM probe positions, different agglomeration states are observed, resulting from two factors, shear rate dependent particle agglomeration and shear-induced particle migration.

scholarly journals Rheological properties of traditional balsamic vinegar: New insights and markers for objective and perceived quality

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Pasquale M. Falcone ◽  
Elisa Sabatinelli ◽  
Federico Lemmetti ◽  
Paolo Giudici
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Dynamic Viscosity ◽  
Flow Instability ◽  
Relaxation Times ◽  
Sensory Properties ◽  
Flow Behaviour ◽  
Shear Rates ◽  
Wide Range ◽  
Balsamic Vinegar

The molecular structure of Traditional Balsamic Vinegar (TBV) undergoes shear-induced and time-dependent jamming transitions due to the high solute concentration and self-assembling phenomena of high molecular size melanoidins with very-long relaxation times (12 years at least or more than 25). The purpose of this work was to perform a descriptive and quantitativeevaluation of relationships between rheological properties, vinegar composition, and perceptual assessment of sensory properties according to the official sensory procedure. With this aim, vinegars having quality traits matching legal requirements for the PDO designation were analyzed for their reducing sugars (glucose and fructose), volatile acidity, fixed acidity, pH, Brix degree, and density as well as for their flow behaviour and dynamic viscosity over a wide range of shear rates. Results showed that flow behaviour of TBV was affected by jamming properties over wide-scale ranges of shear rate producing flow instability below a shear rate of 60s-1. Homogeneous, continuous flow was found at medium-high shear rates with thickening and/or thinning traits. A common onset for the structure scaling was mathematically estimated to occur close to when the density was 1.32 gmL-1. Comparative analysis of rheological, compositional and sensory properties suggested that the colloidal jamming of the vinegar melanoidins dominated the total olfactive and gustative stimuli, and determined the classification of the vinegars that had a higher dynamic viscosity but more homogeneous flow as being of the highest commercial quality category. A robust statistical model was proposed encoding for the top-down decision-making process for quality assignment according to the official sensory procedure, using composition and flow properties as predictor variables. 

scholarly journals Effects of Xanthan gum on rheological properties of Aloe vera-Moringa leaf juice blends

2021 ◽  
Vol 47 (2) ◽  
pp. 583-596
Author(s):  
Victor V Matabura ◽  
Leonard MP Rweyemamu
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Newtonian Fluid ◽  
Xanthan Gum ◽  
Aloe Vera ◽  
Flow Behaviour ◽  
Bingham Model ◽  
Flow Behaviour Index ◽  
Model Equations ◽  
Leaf Juice

Understanding the impacts of hydrocolloid agents on the rheological properties of nutraceutical beverages like Aloe vera-moringa juice blend is very useful for functional properties and product stability. To this end, the effects of xanthan gum on rheological properties in Aloe vera-moringa leaf juice blends were investigated using a Brookfield rheometer. Aloe vera-moringa leaf juice blends were prepared and then incorporated with xanthan gum at different ratios (w/w) of 0.2%, 0.4%, 0.6%, 0.8%, and 1%. The results revealed that the viscosity of Aloe vera-moringa juice blend was strongly affected by the xanthan gum addition. The viscosity profiles depicted a decreasing trend in viscosity when a shear rate increased. The Aloe vera-moringa leaf juice blend changes from a Newtonian fluid to the non-Newtonian fluid as the xanthan gum fraction increases. Moreover, shear stress was observed to increase with increasing in xanthan gum concentrations. For quantitative analysis, both Power-law and Bingham model equations were fitted to experimental data to easily describe the flow behaviour of the Aloe vera-moringa leaf juice blends. The juices added with xanthan gum of 0.4% to 1% were found to show a shear-thinning behaviour, since the flow behaviour index, n < 1. This implies that the apparent viscosity decreases as the shear rate increases. Keywords: Aloe vera juice, Moringa leaf juice, Xanthan gum, Rheological property, Nutraceutical beverage

Pemilihan Bahan Suapan bagi Proses Pengacuan Suntikan Logam Berdasarkan kepada Kajian Sifat Reologi

2012 ◽  
Author(s):  
Norhamidi Muhamad ◽  
Khairur Rijal Jamaludin ◽  
Sri Yulis M. Amin ◽  
Mohd Nizam Ab. Rahman
Keyword(s):  
Stainless Steel ◽  
Injection Molding ◽  
Rheological Properties ◽  
Polymethyl Methacrylate ◽  
Fine Powder ◽  
Flow Behaviour ◽  
Metal Injection Molding ◽  
Coarse Powder ◽  
Flow Behaviour Index ◽  
Behaviour Index

Sifat reologi bahan suapan acuan suntikan logam MIM yang disediakan dengan keluli tahan karat 316L pengabusan gas dan, polymethyl methacrylate (PMMA), polietelena glikol (PEG) dan asid sterik sebagai bahan pengikat telah dikaji. Dai kapilari L/D = 10 telah digunakan dalam kajian ini. Serbuk keluli tahan karat kasar dan halus telah diadunkan dengan bahan pengikat pada beban serbuk 64% dan 65% isipadu. Kesemua bahan suapan mempamerkan tingkahlaku pseudo plastik memandangkan indek tingkahlaku alirannya kurang daripada 1, tetapi indek tersebut berkadar songsang terhadap beban serbuk. Seterusnya, indek tingkahlaku bagi serbuk kasar didapati lebih besar berbanding serbuk halus. Bahan suapan 16_64 lebih peka berbanding bahan suapan yang lain, dan bahan suapan 31_65 pula didapati kurang peka terhadap suhu dan tekanan. Bagaimanapun, kepekaan juga didapati berkadar songsang terhadap beban serbuk. Maka, indek kebolehacuan bagi 31_64 adalah yang terbaik, dan hasil kajian mendapati bahawa beban serbuk 64% isipadu menghasilkan kebolehacuan bahan suapan yang lebih baik. Akhirnya, kajian ini menyimpulkan bahawa kesemua bahan suapan sesuai untuk disuntik ke dalam acuan kerana sifat reologinya menunjukkan penipisan ricih apabila tegasan ricih dikenakan terhadapnya. Bagaimanapun, bahan suapan pada beban serbuk 64% isipadu adalah yang lebih sesuai disebabkan oleh indek kebolehacuan yang lebih tinggi daripada 65% isipadu. Kata kunci: Pengacuan suntikan logam, reologi, indek tingkahlaku aliran, tenaga pengaktifan, indek kebolehacuan Rheological properties of the metal injection molding (MIM) feedstock prepared with gas atomized 316L stainless steel and, polymethyl methacrylate (PMMA), polyethylene glycol (PEG) and stearic acid as binder have been investigated. Capillary rheometer with die of L/D = 10 was used in the investigation. Coarse and fine stainless steel powders were mixed with binders at powder loading of 64% and 65% volume. All feedstocks exhibit pseudo plastics behaviour as the flow behaviour indexes were less than one, but it is inversely proportional to the powder loading. Moreover, the flow behaviour index of the coarse powder is larger than the fine powder particles. Feedstock 16_64 exhibits higher sensitivity among other feedstocks while 31_65 was least sensitive to the temperature and pressure. However, the sensitivity was also inversely proportional to the powder loading. Thus, moldability index of the 31_64 is the best and result shows that powder loading 64% volume gives better moldability to the feedstocks. Finally, the investigation concluded that the feedstocks are suitable to be injection molded because the rheological properties demonstrate a shear thinning when subjected to shear stress. However, feedstock with the powder loading of 64% volume is the most suitable as the moldability index is higher than the 65% volume feedstocks. Key words: Metal injection molding, rheology, flow behaviour index, activation energy, moldability index

scholarly journals A comparative study on the rheological properties of coal water slurries using sodium tripoly-phosphate and carboxy-methyl-cellulose as dispersants

2021 ◽  
Vol 69 (3) ◽  
pp. 100
Author(s):  
M. Ananda Rao ◽  
M. V. Pavan Kumar ◽  
Lenka Srinu
Keyword(s):  
Rheological Properties ◽  
Apparent Viscosity ◽  
Methyl Cellulose ◽  
Flow Behaviour ◽  
Solid Loading ◽  
Carboxy Methyl Cellulose ◽  
Flow Behaviour Index ◽  
Coal Particles ◽  
Behaviour Index ◽  
Carboxy Methyl

The effects of two anionic dispersants (polymeric-carboxy methyl cellulose: CMC and inorganic-sodium tripolyphosphate: STPP) on the rheological properties of coal water slurries (CWS) of varying solid loading were reported and compared. The rheological data was obtained in the shear rate range of 60-160 s<sup>-1</sup> and the data was fitted using power law model. For lower solid concentrations (10% and 20%), shear thickening behaviour was observed while shear thinning nature was seen for the higher solid loadings (30%,40% and 50%) for CWS with both the dispersants. For all slurries, an increase in flow behaviour index values was seen with the increase of dispersant loading. For CWS of 10% and 20% solid loadings, lower values of flow behaviour index was observed with CMC as dispersant. On the other hand, lower values for flow behaviour index was seen with STPP as dispersant for CWS of 30%, 40% and 50% solids loading. Although CMC was found very effective in reducing the apparent viscosity at lower dosages unlike STPP, the apparent viscosity values are quite sensitive to the loading of CMC as dispersant in comparison to STPP. This observed trend may be due to aggressively induced negative charges upon the adsorption of CMC on coal particles at the tested dispersant dosages.

scholarly journals RESEARCH OF RHEOLOGICAL PROPERTIES OF MEDICINAL SYRUP FOR ORAL USE

2020 ◽  
Vol 73 (4) ◽  
pp. 696-699
Author(s):  
Lena L. Davtian ◽  
Galyna P. Kukhtenko ◽  
Alona S. Voronkina ◽  
Viktoria V. Kudria
Keyword(s):  
Rheological Properties ◽  
Mechanical Stability ◽  
Rheological Parameters ◽  
Dynamic Flow ◽  
Shear Rates ◽  
Coaxial Cylinders ◽  
Low Degree ◽  
Newtonian Type ◽  
Rotary Viscometer

The aim of the present research was to investigate the rheological properties of the medicinal syrup for oral administration with glucosamine hydrochloride and levocarnitine. Matherials and methods: Coefficient of the dynamic flow (at shear rates of 3,49 and 10,3 s -1, as well as at shear rates of 27.2 and 149.0 s-1), mechanical stability, the index of destruction and restoration were studied. The rheological (structural-mechanical) properties of the samples were determined using a Rheolab QC rotary viscometer (AntonPaar, Austria) with coaxial cylinders CC27 / S-SN29766. The rheological parameters were studied at the temperature 20±0,5 °С. Results: It is established that the syrup has weakly expressed plastic viscous and thixotropic properties (the hysteresis area for the syrupis 1710.19 Pas/s). Such results characterize the system as a reopex. Conclusions: The results of the study enables classification of the research object as system with a low degree of fluidity. Such dependence is typical for systems of the Newtonian type of flow and characterizes the syrup under investigation as a weakly structured disperse system.

scholarly journals Soft channel formation and symmetry breaking in exotic active emulsions

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
L. N. Carenza ◽  
G. Gonnella ◽  
A. Lamura ◽  
D. Marenduzzo ◽  
G. Negro ◽  
...  
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Self Assembly ◽  
Contractile Activity ◽  
Active Material ◽  
Fluid Flows ◽  
Shear Rates ◽  
Two Phases ◽  
The Stability ◽  
Isotropic Fluid

Abstract We use computer simulations to study the morphology and rheological properties of a bidimensional emulsion resulting from a mixture of a passive isotropic fluid and an active contractile polar gel, in the presence of a surfactant that favours the emulsification of the two phases. By varying the intensity of the contractile activity and of an externally imposed shear flow, we find three possible morphologies. For low shear rates, a simple lamellar state is obtained. For intermediate activity and shear rate, an asymmetric state emerges, which is characterized by shear and concentration banding at the polar/isotropic interface. A further increment in the active forcing leads to the self-assembly of a soft channel where an isotropic fluid flows between two layers of active material. We characterize the stability of this state by performing a dynamical test varying the intensity of the active forcing and shear rate. Finally, we address the rheological properties of the system by measuring the effective shear viscosity, finding that this increases as active forcing is increased—so that the fluid thickens with activity.

The Effects of Fat and Non Fat Dry Matter Concentration and Storage Time on the Physical Properties and Acidity of Yoghurts Made with Probiotic Cultures

2006 ◽  
Vol 12 (6) ◽  
pp. 467-476 ◽  
Author(s):  
Ö. Gün ◽  
N. D. Işsikli
Keyword(s):  
Physical Properties ◽  
Apparent Viscosity ◽  
Dry Matter ◽  
Storage Time ◽  
Shear Thinning ◽  
Flow Behaviour ◽  
Consistency Coefficient ◽  
Flow Behaviour Index ◽  
And Storage ◽  
Behaviour Index

The effects of fat and non fat dry matter (NFDM) concentration and storage time on the physical properties and acidity of yoghurts made using commercial probiotic cultures (ABY and ABT-1) were investigated by using response surface methodology. All yoghurts made with ABY and ABT-1 cultures exhibited shear thinning behaviour. The power low model was used to describe the shear thinning behaviour of yoghurt samples. The flow behaviour index ( n) and the consistency coefficient ( m) were determined. NFDM levels in milk strongly affected syneresis, apparent viscosity at a constant speed of 100rpm, flow behaviour index and the consistency coefficient. Titratable acidity and pH were mainly affected by the storage time. Under all conditions examined, yoghurt made with ABT-1 culture had higher apparent viscosity, consistency coefficient and pH value than those of the yoghurt made using ABY culture.

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