Ioana Stanciu

University of Bucharest | Unibuc · Department of Physical Chemistry

Objectives: To determine the viscosity index of hydraulic oil by three methods. These methods are: the viscosity index determined by a mathematical relationship, using a calculation program and the graphic method. The study also intends to determine the viscosity-temperature coefficient for the hydraulic oil. Methods: To determine the kinematic vis...

The purpose of this article is to determine the rheological behavior of fruit and vegetable purees as well as tomato sauces at a temperature of 25 0 C and to find in the literature a rheological model that describes their behavior. Fruit and vegetable purees as well as tomato sauces have a non-Newtonian behavior. These were studied with the Brookfi...

In this article we studied the olive oil extracted from the cold pressed fruits and separated by centrifugation. The rheological models found in the literature for the dependence of the shear rate on the shear stress are: the Herschel-Bulkley model, the Ostwald model and the Bingham model. By linearizing the obtained data, we found two models that...

Significant progress has been made on biopolymers in recent years. Biopolymers are preferred to other materials because they have specific physical, chemical, biological , biomechanical, and degradation properties. Many natural or synthetic biopoly-mers can degrade hydrolytically or enzymatically and are used for many applications.

Rheology is a branch of science with multiple implications in numerous sectors of industry, also constituting a generous field due to its multidisciplinary character. Thus, solving a problem in rheology calls for knowledge from modern mathematics, physics, chemistry, chemical and mechanical engineering, and materials science. Driven by the appearan...

Palm oil is dark yellow to red with a sweet taste and violet scent. Under the action of oxygen in the air, palm oil discolors due to the oxidation of carotene. The sample at different temperatures was recorded at different shear rates. Based on the rheograms (graph of the average shear stress versus shear rate), the studied ones proved to be Newton...

Food gums are hydrophilic colloids, which due to their functional properties are used in the food industry. For non-Newtonian rubber solutions to these factors must be added the dependence between the shear stress and the shear rate. Experimental data were obtained with a Haake RV20 rotary viscometer with a con-plate system. The range of shear spee...

The proposed rheological study for six vegetable oils which are: olive oil, coconut oil, almound oil, sesame oil, cottonseed oil and sunflower oil shows their non-Newtonian behavior. With the help of the Rheotest viscometer I determined the shear stress and then the dynamic viscosity. The analysis of the rheograms shows a decrease in the dynamic vi...

This article presents the study of the rheological behavior of ruminal fluid in sheep obtained from barley feed and barley and yeast feed. We studied the influence of shear rate on the experimental values of shear stress and apparent viscosity for ruminal fluid obtained from feed with 40% barley. Measurements were made at 39° C, with a Physica MCR...

In this article I present the rheological behavior of the olive oil purchased from the producer in the temperature range 40-100oC. The oil was studied at different shear rates and shear stresses depending on the temperature. At high temperatures there is a minimum viscosity between 80 and 100oC. No thixotropic effects were observed for olive oils....

Mathematical models that describe the variation of soybean oil viscosity with temperature according to the recent WLF and VTF (or VFT) equations and traditionally by the Arrhenius equation. The Arrhenius equation shows that the viscosity of the oil is proportional to the absolute temperature and is determined by the activation energy parameter. In...

In this article, based on experimental data, we obtained three dependence relations of dynamic viscosity versus temperature by polynomial and exponential fitting. The correlation coefficients have values close to unity which proves that the obtained relations accurately describe the non-Newtonian behavior of Olive oil.

The rheological behavior of orange honey was studied in the temperature range 25-45 degrees Celsius with Haake VT 550 viscometer when the HV1 viscosity sensor at high shear rates 3.3 and 1312s-1. The assortment of orange honey has a dilating behavior being influenced by concentration and humidity. Honey was studied with a humidity of 16%, 17%, 19%...

This article presents the comparative study of rapeseed oil with hydraulic oil (h depending on the g and h depending on the temperature) for a vegetable oil and a hydraulic oil between temperatures of 40 and 90 O C celsius. The two oils were studied with the Haake VT 550 viscometer with VH 1 sensor. The obtained curves show an exponential decrease...

The study was performed to determine the effect of the logarithm of the viscosity on the inverse of the absolute temperature for orange honey. Based on the studied rheograms, it turned out to be a non-Newtonian fluid. The shear range used did not significantly affect the absolute viscosities of orange honey at different temperatures. The absolute v...

This article presents the dependence of dynamic temperature viscosity and shear rate for rapeseed oils used as biodegradable lubricant and SAE 10W. The studied rheograms show the dependence of the dynamic shear rate viscosity as well as the dependence of the dynamic temperature viscosity. From the rheograms there is a decrease in the dynamic viscos...

In this article I have presented the rheological characteristics of castor oil used as a biodegradable lubricant. The rheograms of castor oil have quite different slopes. The highest slope is at shear speed 3.3s-1 , and the smallest slope is at 120s-1. From the representation of the dependence of the dynamic viscosity on the correlation coefficient...

This article is focused on evaluating the rheological properties of tomato ketchup. The purpose of the paper was to show the importance of knowledge about the rheological properties of ketchup and to find new more adequate equations of the temperature-viscosity dependence. All measurements were performed under the same temperature conditions at app...

There are several mathematical models used to describe the rheology of non-Newtonian fluids, but these are not limited to the following models; Power Law, Bingham, Hershel-Buckley, and Casson. Selecting the best rheological model that accurately represents the shear rate analysis with the shear stress is one of the rheology's wishes. Therefore, thi...

In this paper, new rheological models for castor oil are proposed. The aim of this study was to find a linear, exponential, and polynomial dependence between shear stress and shear rate of castor oil using tree equation. Equation constants 0  , A, B, and C were determined by fitting linear, exponential, and polynomial. The castor oil has been eval...

This article presents the dependence on the dynamic viscosity of the temprature and the shear rate for the vegetable oils (soybean, corn, olives, rapeseed) used as biodegradable lubricants. From the reogrames we observe a decrease of the dynamic viscosity with temprature and the shear rate for all four types of oils of the Vegetable oils analyzed,...

The dynamic viscosity of coconut oil was measured as a function of shear rate at different temperature ranged from 40°C to 100°C. In this study, shear stress and the dynamic viscosity as a function of temperature of coconut oil decrease with increasing temperatures. Three and multi-constant formula were proposed to obtain more suitable prediction o...

Poster

This paper proposes new rheological models for olive oil. The purpose of this study was to find an exponential dependence between temperature and dynamic viscosity of olive oil, using one equation. Equation constants ln?0, A1 and t1 were determined by fitting exponential. The olive oil have investigated using a Haake VT 550 Viscotester developing s...

Extracted from rapeseed oil was subjected to purification and refining process and then characterized in terms of rheological, ie dynamic viscosity dependence study in terms of speed shear constant temperature. The results show that at 40 0 C, 60 0 C, 80 0 C and 90 0 C dynamic viscosities of oil decreases with shear rate. At higher shear rates of 2...

In this article we have presented the dependence of dynamic temperature vicinity at all shear rates for coconut vegetable oil used as biodegradable lubricant. Dynamic viscosity decreases exponentially with increasing temperature at all shear rates. At high temperatures the dynamic viscosity decreases less significantly. The shear speed increases li...

Objectives: To study the viscosity index for oil used as biodegradable lubricant using tree methods. Methods: Viscosity index for oil used as biodegradable lubricant (coconut oil, soybean oil, corn oil, rapeseed oil) was determined using a set of Schott Ubbelohde-type viscometers selected according to the values of their constants, so that the marg...

The aim of the study was to investigate rheological properties of soybean oil. The soybean oil was investigated using a Haake VT 550 Viscotester at shear rates ranging between 3 and 120 s-1 and measuring viscosity from 10 4 to 10 6 mPa·s when the HV 1 viscosity sensor is used. The temperature was ranged between 40 and 90 o C and the measurements we...

This article proposes new rheological models for soybean oil. The purpose of this study was to find an exponential dependence between temperature and the logarithm dynamic viscosity of soybean oil, using one equation. Equation constants ln η 0 , A 1 and t 1 were determined by fitting a suitable correlation. The soybean oil investigated using a Haak...

Obiectives: In this article I have been looking at the determination of the solubility parameter by two methods for an additive hydrogenated poly (isoprene-co-styrene) used in lubricating oils. To determine the solubility parameter, it is necessary to know the intrinsic viscosities of the polymer hydrogenated poly (isoprene-co-styrene) in as many s...

In this article I have been working for the determination of the solubility parameter by two methods for an additive KELTAN 4200 used in lubricating oils. To determine the solubility parameter, it is necessary to know the intrinsic viscosities of the polymer in as many solvents with different solubility parameters. Determination of the partial and...

In this paper, we found three mathematical models that show the shear shear speed dependence on the shear stress. Experimental data for one type of coconut oil were used to calculate the accuracy the proposed models. Equation constants were determined by exponential beast curves obtained at different shear rates using the program Origin 6.0. The co...

Viscosity is one of the most important parameters for vegetable oil. A new mathematical viscosity model was developed based on freely sliding molecules with Lennard-Jones’ potential and linear density-temperature relation. According to the functions derived from the new model, viscosity gradually decreases with temperature at atmospheric pressure....

Biodegradable oils are at present a powerful performance in the field of lubrication of machinery and machines that work predominantly under conditions that make it possible to pollute the environment. This refers to machinery and equipment in agriculture, construction industry, marine, forestry, printing, drilling, railways, automotive, and food i...

This article proposes new rheological models for soybean oil. The purpose of this study was to find an polynomial dependence between temperature and dynamic viscosity of soybean oil, using one equation. Equation constants A, B 1 and B 2 were determined by fitting polynomial. The soybean oil have investigated using a Haake VT 550 Viscotester develop...

The soybean oil was carefully studied in recent years because they may constitute a raw material for biodegradable lubricants getting organic. These oils are an alternative to synthetic mineral oils. This article presents rheological behavior of soybean oil. The dynamic viscosity of soybean oil was determined at temperatures range between 313-373 K...

To establish the ability of copolymer hydrogenated poly (isoprene-co-styrene) solutions in SAE 10W mineral oil as solvent to perform at low and high temperatures in a vehicle's engine, that is their capacity to improve the oil viscosity index of their 3, 3.5, 4, 4.5 and 5 % solutions were determined two methods. The kinematic viscosities of the con...

In this paper viscosity index of soybean oil was determined using tree methods. Viscosity index was calculated from the measured viscosity at 40°C and 100°C using ASTM Method D 2270 and was graphically determined using ASTM D 341. Viscosity index calculation was performed with a computer program using kinematics viscosity at 40°C and 100°C. The vis...

Viscosity study has been widely studied by scientist and engineers on various purposes. These include polymer science, heat transfer phenomena, petroleum reservoir development, coatings; scale modeling of magnetic intrusion, oil degradation, lubrication, etc. This article proposes four relationships of dynamic viscosity-temperature dependence for s...

This article shows the rheological behavior of soybean oil. Soybean oil were investigated using a Haake VT 550 Viscotester developing shear rates ranging between 3 and 120 s-1 and measuring viscosities from 10 4 to 10 6 mPa·s when the HV 1 viscosity sensor is used. The temperature ranging was from 313K to 373K and the measurements were made from 10...

To establish the ability of copolymer polyethylene-propylene solutions in SAE 10W mineral oil as solvent to perform at low and high temperatures in a vehicle's engine that is their capacity to improve the oil viscosity index of their 3.0, 3.5, 4.0, 4.5 and 5.0 % solutions were determined two methods. The kinematic viscosities of the concentrated co...

To establish the ability of Infineum SV 260 and Paratone 8900 copolymers solutions in SAE 10W mineral oil as solvent to perform at low and high temperatures in a vehicle's engine, that is their capacity to improve the oil viscosity index, the viscosity-temperature characteristics of their 3, 3.5, 4, 4.5 and 5 % solutions were determined. The kinema...

This article presents a study of log dynamic viscosity variation with log shear rate for rapeseed oils obtained from different stages of processing. The for each of the 5 types of oils studied was determined the dynamic viscosity by changing the shear rate from 3.3 to 120 s-1 and temperature from 40 o C to 90 o C with Haake VT 550 viscometer equipp...

In this article we determined the rheological characteristics of polyethylene-propylene copolymer solutions. The 3, 6, 10 and 12 % copolymer polyethylene-propylene solutions concentration were studied. The temperature range studied was 40 – 90 o C, from 10 to 10 degrees to the shear in the range 3-1312 s-1 in domain 2 and speed measurements were ma...

In this paper I undertook to determine the rheological characteristics of copolymer hydrogenated poly (isoprene-co-styrene) solutions concentrated. The solutions studied were the concentrations 3, 6, 10 and 12 %. Rheology solutions are affected by concentration, temperature, shear rate and shear stress. The empirical relationship found, the depende...

The 3 %, 6 %, 10 % and 12 % of copolymer hydrogenated poly (isoprene-co-styrene) solutions concentrations were studied in the temperature range 313 – 363 K, shear rates between 3 and 1312 s-1 viscometer Haake VT 550. Rheological model described the equation (3) describes the rheological behavior of the 3 %, 6 %, 10 % and 12 % solution of concentrat...

In this paper I undertook to determine the rheological characteristics of the copolymer polyethylene-polypropylene solutions. I have studied the 3, 6, 10, and 12% concentrated solutions for a temperature interval from 40°C and 90°C in 10 degree steps, and for the shear rate from 3 to 1312 s-1 in the second domain. The measurements were performed us...

In this paper I undertook to determine the rheological characteristics of the copolymer hydrogenated poly(isoprene-co-styrene) solutions. I have studied the 3% concentrated solutions for a temperature interval from 40°C and 90°C in 10 degree steps, and for the shear rate from 3 to 1312 s-1 in the second domain. The measurements were performed using...

In this paper I undertook to determine the rheological characteristics of the copolymer hydrogenated poly(isoprene-co-styrene) solutions. I have studied the 3, 6, 10, and 12% concentrated solutions for a temperature interval from 40°C and 90°C in 10 degree steps, and for the shear rate from 3 to 1312 s-1 in the second domain. The measurements were...

In this paper proposes have found two mathematical equations that describe the rheological behavior of refined sunflower oil. Mathematical equations were found by plotting the logarithm of dynamic viscosity depending on the shear rate logarithm of refined sunflower oil. Refined sunflower oil was studied by Haake VT 550 viscometer for shear rates be...

This paper presets the study of the rheological characteristics of the concentrated polyethylene-polypropylene copolymer solutions over the temperature range of 313-363 K and for shear rates between 3 and 1312 s-1. The measurements were performed on a Haake VT 550 rotational rheometer with a HV1 sensor. The rheology of the concentrated solutions is...

Paratone 8900 is used as automotive for as viscosity improvers for multi-grade oils. In this study we established the physico-chemical analyses vized of a copolymer Paratone 8900 used as viscosity improvers for SAE 10W-40 mineral oil was: spectroscopy FTIR, thermo-gravimetric differential thermal analysis (TG-DTA), and the differential scanning cal...

This paper presets the study of the rheological characteristics of the concentrated polyethylene-polypropylene copolymer solutions over the temperature range of 313-363 K and for shear rates between 3 and 1312 s-1. The measurements were performed on a Haake VT 550 rotational rheometer with a HV1 sensor. The rheology of the concentrated solutions is...

This paper presets the study of the rheological characteristics of the hydraulic oil over the temperature range of 40-90oC and for shear rates between 3 and 1312 s-1. The measurements were performed on a Haake VT 550 rotational rheometer with a HV1 sensor. The analyzing results, it was noticed a decrease in dynamic viscosity for the temperature and...

In this paper to determine two models theoretical on literature the rheological characteristics for variation dynamic viscosity with absolute temperature for refined sunflower oil. The rheological behavior of the refined sunflower oil has been studies on a Haake VT 550 viscosimeter with a HV1 sensor that provides for shear rates from 3 to 1312 s-1...

Copolymer Shelvis is used as automotive for as viscosity improvers for multi-grade oils. The properties chemical and physical of copolymer are: physical state – solid, form – white solid blocks, colour – compressed crumbs, odourless, flashpoint > 150oC, insoluble in water, is not material hygroscopic, stable, density (15oC) – 0.272 g • cm-3 and non...

This paper presets the study of the rheological characteristics of the concentrated polyethylene-polypropylene copolymer solutions over the temperature range of 313-363 K and for shear rates between 3 and 1312 s-1. The measurements were performed on a Haake VT 550 rotational rheometer with a HV1 sensor. The rheology of the concentrated solutions is...

In this article we presented viscosity index for sunflower oil using three method. Viscosity index are calculated from the measured viscosity at 40 and 100oC according to ASTM D 2270, using program VI and graphical method from ASTM D 341. The viscosity-temperature coefficients for sunflower oil were calculated from the measured viscosity at 40 and...

Rheology is a simple analysis that is being more and applied to determine the physical behavior of solutions, suspensions and mixtures. The basic parameter, obtained in the rheological study of liquid foods, is viscosity, used to characterize the fluid texture. Rheology is concerned with how materials respond to applied forces and deformations. Bas...

The sunflower oil was carefully studied in recent years because they may constitute a raw material for biodegradable lubricants getting organic. These oils are an alternative to synthetic mineral oils. The biodegradable oils represent now an ingenious solution in lubrication engineering for equipment which works preponderantly in conditions that ha...

The global and partial solubility parameters and radii of interaction spheres of a copolymer EPDM were determined from solubility data and intrinsic viscosities using 13 solvents both by the classical Hansen’s method and an improved one. The obtained results are in good agreement each other and with intrinsic viscosity data.

Rheology of vegetable oils is concerned with how oil responds to applied forces and deformations. The basic parameters of the stress (force per area) and strain (bending length), are essential for all rheological assessments for sunflower oil. The fundamental parameter in study rheological behavior of a vegetable oil is viscosity. This article prop...

In this article we calculated dynamic viscosity for a number of vegetable oils (crude rapeseed oil, degummed rapessed oil, rapeseed oil dry, rapeseed oil bleached and rapeseed oil refined) at temperatures from 313K to 363K. The some empirical relations that describe the temperature dependence of dynamic viscosity were fitted to the experimental dat...

This paper proposes two new relations of dependence of log dynamic viscosity depending on log absolute temperature shear rates between 3.3 and 120s-1. The constants A, B, and C were determined by Origin 6.0 software by fitting linear or polynomial curves obtained from experimental data. The two proposed relationships give correlation coefficients c...

The sunflower oil exhibit positive production trends and show good potential for a variety of industrial applications. The worldwide production of oilseed is increasing day by day, but at present it is costly compared to petroleum based oils. Economic losses are justified when considering the life cycle advantages of vegetable based lubricants. The...

To establish the ability of copolymer poly (alkyl methacrylate) solutions in rapeseed oil as solvent to perform at low and high temperatures in a vehicle's engine, that is their capacity to improve the oil's viscosity index, the viscosity/temperature characteristics of their 5, 8, 12 and 18% solutions were determined. It was obtained polymer increa...

In this work it was proposed a study concerning the rheological behavior of sunflower oil. This oil has a pseudoplastic behavior at studied temperatures. The equations of dynamic viscosity depending on shear rate between 40 °C and 100 °C for sunflower oil were used. The A, B, and C constants were obtained using the Origin 6.0 software by fitting ex...

The refined rapeseed oil were carefully studied in recent years because they may constitute a raw material for biodegradable lubricants getting organic. These oils are an alternative to synthetic mineral oils. This article presents rheological behavior of refined rapeseed oil. The dynamic viscosity of refined rapeseed oil was determined at temperat...