Initial Apparent Viscosity Research Articles

Synthesis of guar gum maleate under dry conditions: Reaction kinetics and characterization

In the present study, a novel environment friendly dry method for preparation of guar gum maleate (GGM) with varying degrees of substitution (DS; 0.02–1.04) was optimized. GGM with a maximum DS of 1.04 was successfully synthesized using guar gum (GG) and maleic anhydride (MA) in proportion of 1: 1 at 80 °C with 4 h of reaction time. The activation energy for the reaction was determined to be 36.91 ± 3.61 kJ mol−1 with pre-exponential factor of 1392 min−1. Esterification of GG was confirmed by FT-IR and 13C NMR. Analysis using size exclusion chromatography (SEC) indicated a decrease in weight average molecular weight (Mw) of the polymer with an increase in polydispersity index (PDI) due to esterification. In comparison with GG, GGM displayed increased hydrophobicity and reduced thermal stability, as analysed by differential scanning calorimetry (DSC). Rheological studies of GGM revealed that initial apparent viscosity decreased with increasing DS. For the first time, the study offered valuable insights on GGM synthesis under dry solvent-less reaction conditions enabling simpler and scalable synthesis process.

Optimization of Composite Grouting Material Proportioning Based on Regression Analysis Method

In order to improve the impermeability of ordinary “cement–water glass” double-liquid grouting material, this study prepares a composite grouting material with sodium bentonite, cement, and water glass as the main materials, water-reducing agent, and early strength agent as activators. In this study, orthogonal tests were conducted using an L16(45) orthogonal table and the test results were analyzed using regression analysis. Using bentonite instead of partial cement, the experimental factors of the bentonite ratio, glass slurry ratio, water-reducing agent admixture, and early strength agent admixture were used to study the laws of single-factor and two-factor interactions on the initial apparent viscosity, setting time, and compressive strength of composite grouting materials. After obtaining the optimal ratio of composite grouting materials, the mechanism of formation of material strength and seepage resistance properties was revealed. The results show that the mass ratio of bentonite to cement and the mass ratio of water glass to slurry have a large effect on the material properties, and there is an interactive effect of several factors at the same time. The optimal ratio of the material is 28.42% water, 36.58% cement, 6.20% bentonite, 0.04% water-reducing agent, 0.9% early strength agent, and 27.85% water glass. The microstructural analysis shows that the denseness of the stone body structure is enhanced, and thus the strength and impermeability of the material are improved. This composite grouting material improves injectability and seepage resistance and is more suitable for underpinning grouting of weakly cemented soft rocks, but the ratio optimization method and model used in this study can be applied to other materials.

Effect of High Pressure Homogenization-Modified Soy 11S Globulin on the Gel and Rheological Properties of Pork Myofibrillar Protein

The changes in texture and rheological characteristics, water holding capacity, and microstructure of pork myofibrillar protein with high-pressure homogenization-modified (0-150 MPa) soy 11S globulin were studied. The cooking yield, whiteness values, texture properties, shear stress, initial apparent viscosity, storage modulus (G'), and loss modulus (G″) of pork myofibrillar protein with high-pressure homogenization-modified soy 11S globulin were significantly increased (p < 0.05) compared with the sample of 0 MPa, and centrifugal yield was significantly decreased, except for the sample of 150 MPa. Therein, the sample of 100 MPa had the largest values. Meanwhile, the water and proteins bonded more tightly because the initial relaxation times of T2b, T21 and T22 from pork myofibrillar protein with high-pressure homogenization-modified soy 11S globulin were shorter (p < 0.05). Overall, the water-holding capacity, gel texture and structure, and rheological properties of pork myofibrillar protein could improve when adding soy 11S globulin treated with 100 MPa.

Efficient Separation and Recovery of Petroleum Hydrocarbon from Oily Sludge by a Combination of Adsorption and Demulsification.

The treatment of oily sludge (OS) can not only effectively solve environmental pollution but also contribute to the efficient use of energy. In this study, the separation effect of OS was analyzed through sodium lignosulfonate (SL)-assisted sodium persulfate (S/D) treatment. The effects of SL concentration, pH, temperature, solid–liquid ratio, revolving speed, and time on SL adsorption solubilization were analyzed. The effects of sodium persulfate dosage, demulsification temperature, and demulsification time on sodium persulfate oxidative demulsification were analyzed. The oil removal efficiency was as high as 91.28%. The results showed that the sediment was uniformly and finely distributed in the S/D-treated OS. The contact angle of the sediment surface was 40°, and the initial apparent viscosity of the OS was 56 Pa·s. First, the saturated hydrocarbons and aromatic hydrocarbons on the sediment surface were adsorbed by the monolayer adsorption on SL. Stubborn, cohesive oil agglomerates were dissociated. Sulfate radical anion (SO4−·) with a high oxidation potential, was formed from sodium persulfate. The oxidation reaction occurred between SO4−· and polycyclic aromatic hydrocarbons. A good three-phase separation effect was attained. The oil recovery reached 89.65%. This provides theoretical support for the efficient clean separation of oily sludge.

The Effects of Multiple Parameters on Initial Apparent Viscosity and Rheological Behavior in a Liquid-Phase Paddy Field

Highlights Soil rheological properties in the liquid phase under various clay contents, moisture contents, and settling times were investigated. A numerical model of the initial apparent viscosity was established and verified. The change in soil rheological behavior at different rotating speeds was analyzed. Abstract. It is particularly important to study the rheological properties and rheological behavior of liquid-phase paddy soil to improve the working efficiency of power machinery in paddy fields. In this research, a rotational rheometer was used to record the shear stress, shear rate, and apparent viscosity of the soil during the test. Additionally, a numerical model was established to explore the effects of soil clay content, moisture content, and settling time on soil rheological properties. Through single factor analysis, the contribution rate of each factor to the change in the initial apparent soil viscosity was ranked as follows: moisture content (X2) &amp;gt; soil clay content (X1) &amp;gt; settling time (X3). Subsequently, the variations in shear stress and apparent viscosity at different shear rates were explored. The changing trend of soil rheological behavior was mainly related to soil texture, in which silty loam was thixotropic and clay loam was gelatinous. The prediction models for the initial apparent viscosity were validated, and the results showed great agreement. The research evaluated and predicted the rheological behavior of liquid-phase paddy field soil and provides a reference for the design, development, and use of paddy field power machinery. Keywords: Apparent viscosity, Clay content, Moisture content, Rheology, Settling time, Shear stress.

Effects of high pressure homogenization on the solubility, foaming, and gel properties of soy 11S globulin

The effects of different homogenization pressure levels on the solubility, particle size, surface hydrophobicity, free sulfhydryl content, surface tension, water distribution and mobility, rheological, foaming and gel properties of soy 11S globulin were investigated in this study. High-pressure homogenization treatment (50–150 MPa) significantly increased the magnitude of protein zeta potential, solubility, while reduced the particle size, which increased surface hydrophobicity, and exposure to free sulfhydryl and disulfide bonds, as well as surface tension, foaming capacity and stability, elasticity index, macroviscosity index, initial apparent viscosity and shear stress. On the other hand, excessive pressure treatment at 150 MPa caused solubility, surface hydrophobicity, exposure to free sulfhydryl, the elasticity index, macroviscosity index, initial apparent viscosity and shear stress to decrease. The gel strength and water immobilization also increased, whereas the mobility of the water was low. Overall, our results show that high-pressure homogenization improves the physicochemical, foaming and gel properties of 11S globulin.

Effects of deproteinization on rheological properties of polysaccharides from Rosa acicularis ‘Lu He’ and Rosa acicularis Lindl fruits

Polysaccharides from the fruits of Rosa acicularis are one of the main functional components with superior biological activities and physicochemical properties. Rosa acicularis 'Lu He' is a new variety derived from the wild type Rosa acicularis Lindl. A comparative study was performed on the chemical composition and rheological properties of polysaccharides of rosehip from Rosa acicularis 'Lu He' (RLHP) and Rosa acicularis Lindl (RLDP) before and after deproteinization. The polysaccharide extracts, regardless of deproteinization, were acidic heteropolysaccharides composed of 48.3–51.6% carbohydrate and 29.2–43.2% uronic acid on dry weight basis and small amounts of protein (1.8–6.2%) and polyphenol (2.1–6.3%). Steady shear and frequency scanning measurements were used to evaluate the changes in concentration, temperature, pH and salts on the apparent viscosity and dynamic viscoelasticity of polysaccharide of rosehip solutions. The results showed that the apparent viscosity of RLHP was higher than that of RLDP at the same concentrations (2–6%), while apparent viscosity of RLHP and RLDP increased by 7.2% and 20.5% after deproteinization, respectively. Solutions of polysaccharide of rosehip exhibited shear-thinning behaviors, and higher concentrations caused more significant pseudoplastic effects. The solution properties changed from pseudoplasticity to plasticity when the initial apparent viscosity was below 7.5 mPa s. Thixotropy of polysaccharides of rosehips was stronger after protein removal; moreover, the polysaccharides before deproteinization (RLHP-1, RLDP-1) exhibited better gel properties than the deproteinized polysaccharides (RLHP-2, RLDP-2). This rheological property information will help proper product design to ensure the stability of food products enhanced with polysaccharides from rosehips.

Deep submarine landslide contribution to the 2010 Haiti earthquake tsunami

Abstract. The devastating Mw 7.1 Haiti earthquake in 2010 was accompanied by local tsunamis that caused fatalities and damage to coastal infrastructure. Some were triggered by slope failures of river deltas in the close vicinity of the epicenter, while others, 30 to 50 km to the north across the Bay of Gonâve, are well explained by the reverse component of coseismic ground motion that accompanied this mostly strike-slip event. However, observations of run-up heights up to 2 m along the southern coast of the island at distances up to 100 km from the epicenter, as well as tide gauge and DART buoy records at distances up to 600 km from the epicenter, have not yet received an explanation. Here we demonstrate that these observations require a secondary source, most likely a submarine landslide. We identify a landslide scar 30 km from the epicenter off the southern coast of Haiti at a depth of 3500 m, where ground acceleration would have been sufficient to trigger slope failure in soft sediments. This candidate source, 2 km3 in volume, matches observations remarkably well assuming that the sediment collapse obeys a viscous flow with an initial apparent viscosity of 2×105 Pa s. Although that particular source cannot be proven to have been activated in 2010, our results add to a line of evidence that earthquake-triggered submarine landslides can cause significant tsunamis in areas of strike-slip tectonic regime.

Effects of pectins and sugars on β-carotene bioaccessibility in an in vitro simulated digestion model

There is lack of information about the effects of pectin and sugars on carotenoid delivery in a simple juice model system. Therefore, the effect of pectin and sugars on β-carotene bioaccessibility (CBA) and the characteristics of digestive fluids in juice model systems were studied. Carotenoid retention ratio (CRR) in the small intestine and the characteristics of digestive fluids, including color parameters and rheological properties, were investigated to gain insight into the mechanism that can alter carotenoid bioaccessibility. Results illustrated that higher pectin concentration, medium methoxyl pectin (MMP), and low methoxyl pectin (LMP) increased the initial apparent viscosity. However, there was no marked difference for the apparent viscosity of all systems in the stomach and small intestine phases. Generally, systems with sugars had higher CRR than those with pectin. Lower pectin concentration increased CBA. Systems with MMP had higher CBA than those containing high methoxyl pectin (HMP) and LMP; therefore, the effects of degree of methoxylation (DM) were not proportional to CBA. Among systems with different sugars, sucrose could achieve the highest CBA (4.59%). A comprehensive investigation of the effects of pectin and sugars on carotenoid delivery during digestion will be a theoretical guidance to improve nutritional qualities of juice products.

A novel strategy to maintain the long-term viscosity stability of konjac glucomannan hydrosol by using zinc ion

The viscosity of konjac glucomannan (KGM) hydrosol dropped sharply after a period of approximately 12 h. This is a well-known problem which producers are trying to solve. Several salts were added to KGM hydrosols to attempt to improve the long-term viscosity stability of KGM hydrosol. Compared with native KGM hydrosol and KGM hydrosol with Ca2+ and Mg2+, the initial apparent viscosity of KGM hydrosol with Zn2+, in the form of zinc chloride was higher, and the long-term viscosity stability was also significantly increased. This was attributed to Zn2+ preventing the degradation of KGM induced by microbial growth. Bacillus and Paenibacillus were “culprits” in the viscosity reduction of KGM hydrosol. Zn2+ maintained the long-term viscosity stability of the hydrosol by inhibiting microbial growth and enzyme activity of β-mannanase. Zinc sulfate, zinc acetate, and zinc gluconate being edible salts were also used as a source of zinc ions and showed a similar long-term stabilization effect on the viscosity of the KGM hydrosol. These provided a realistic strategy to replace non-edible additives with edible zinc salts for food industry applications.

The Effect of Particle Shapes on the Field-Dependent Rheological Properties of Magnetorheological Greases.

The transient response of magnetorheological (MR) materials, in general, is very important for design consideration in MR-based devices. Better response to magnetic fields is beneficial for a better response rate to the electrical current applied in the electromagnetic coil. As a result, MR-based devices would have a high response to external stimuli. In this work, the principal characteristics of magnetorheological greases (MRGs) which have two different particle shapes are experimentally investigated. One type of particle distributed in the grease medium is conventional spherical-shaped carbonyl iron (CI) particles, while the other is plate-like CI particles made using a high-energy rotary ball mill from spherical CI particles. A set of bidisperse MRG samples are firstly prepared by adjusting the weight percentage of the plate-like CI particles and mixing with the spherical CI particles. Subsequently, three important properties of MRGs in terms of their practical application are measured and compared between the two different particle shapes. The field-dependent apparent viscoelastic properties of the prepared MRG samples are measured, followed by the field-dependent storage and loss moduli using an oscillatory shear rheometer. In addition, the transient response time, which indicates the speed in the actuating period of MRGs, is measured by changing the strain amplitude. Then, a comparative assessment on the three properties are undertaken between two different particle shapes by presenting the corresponding results in the same plot. It is shown that the bidisperse MRG with plate-like CI particles exhibits an increase in the initial apparent viscosity as well as stiffness property compared to the MRG with spherical particles only.

Rheological Characteristics of Yoghurt with Varying Levels of Milk Fat Globule Membrane

The study on the potential applications of milk fat globule membrane (MFGM) material as an ingredient in processed food has become of great interest in the dairy industry today due to the functional and bioactive properties it possessed. Here, we investigated the effects of varying concentrations of MFGM material isolated from butter milk on the rheological properties of yoghurt. Based on the results, the enrichment of MFGM materials significantly affected the rheological properties of yoghurt. Yoghurts enriched with buttermilk MFGM materials showed shear thinning behavior which was higher than the control. They exhibited a thixotropic behavior as well, as the viscosity of yoghurts enriched with buttermilk MFGM material decreased when subjected to increasing shear rate. The enrichment of higher concentrations of MFGM material isolated from buttermilk produced a gel with high initial apparent viscosity but collapsed rapidly when shear was applied; but still the final viscosity was higher than control. Further investigation should be done on the effects of MFGM materials on the properties of yoghurt. An oxidative stability study on the MFGM enriched yoghurt should be conducted. Duration of experimental conduct such as on the storage time can be lengthened to provide a clearer picture on the evolution of yoghurt gel during storage. Study on the effects of MFGM materials at various pasteurization temperature-time, and different incubation temperature-time combinations should be looked into.

The isothermal sintering of the single-phase non-stoichiometric niobium carbide (NbC1−x) and tantalum carbide (TaC1−x)

The previous studies have shown that it is possible to obtain NbC1−x and TaC1−x single-phase, dense polycrystals during pressure-less sintering at temperatures below 2000 °C. The paper presents results of investigations concerning a model description of the sintering process of the carbides using two sintering models. In order to study the sintering process of the carbides a sintering model was proposed which was a modification of the sintering model proposed by Frenkel. The model is valid for non-crystalline viscous solids in which the viscosity term was assumed to be linearly related to time. Parameters describing the sintering process of the carbides, i.e. the initial shrinkage rate α−1, the limit of the shrinkage in infinite time β−1 and the initial apparent viscosity η0 of the system were determined using the Frenkel's model. The attempt has been made to determine the mechanisms of mass transport dominating at each sintering stage according to the Kuczynski's model applied to the sintering process of the carbides. The collected data enabled full characterization of the sintering process of the niobium and tantalum carbides.

Bonding Quality of Chemically‐Modified Soybean Protein Concentrate‐Based Adhesives in Particleboards from Rice Husks

AbstractThe aim of the present study was to upgrade the bonding quality and water resistance of medium‐density particleboards based on rice husks (RH) as a wood substitute and soybean protein concentrate (SPC) as the binder via chemical modification of SPC. Alkali (A), citric acid (CA) and boric acid (BA) were used to modify proteins and the carbohydrate complex in SPC. The effect of chemical treatment performed on SPC was followed by Fourier transform infrared, differential scanning calorimetry, thermo‐gravimetric analysis and initial apparent viscosity measurements. Board properties were evaluated in terms of internal bond (IB) and physical properties. Results revealed that boards bonded with SPC treated with boric acid, exhibited the highest IB and the lowest water absorption and thickness swelling at 2 and 24 h, due to cross‐linking reactions with exposed OH‐groups in the amorphous region of cellulose of RH. Results demonstrate that boric acid‐modified–SPC‐bonded boards met the requirements of IB recommended by the US Standard ANSI A208.1‐2009 for M1, MS, M2 and M3‐grade medium‐density particleboards but failed to pass the thickness swelling required. This issue of BSPC‐RH boards is compensated for by the benefit of being formaldehyde‐free which makes them suitable for indoor applications.

Role of initial apparent viscosity and moisture content on post irradiation rheological properties of guar gum

Guar gum is a polygalactomannan used in various industries. Previous studies on radiation processing of guar gum showed a decrease in its viscosity during irradiation. Present work reports rheological properties and magnitude of depolymerization as affected by initial apparent viscosity (AV) and moisture contents of guar gum during irradiation processing. Rate of degradation was found to be dependent on the initial moisture content of guar gum during irradiation. D 50 values for oven dried gum was 490 Gy and it increased to 1250, 2600 and 2420 Gy in samples having 10%, 25% and 30% initial moisture respectively. EPR spectroscopy showed disappearance of anisotropic signals with increasing moisture content indicating crosslinking of polymer. FTIR spectroscopy results suggested that there were no major chemical functional group transformations during irradiation.

Effect of high-pressure treatment on normal rice and waxy rice starch-in-water suspensions

The effects of treatment pressure (⩽700 MPa), temperature at treatment (10–60 °C), and treatment duration (0–30 min) on the gelatinization of normal and waxy rice starches were investigated. Pressure-treated starch suspensions were examined for pasting behaviour, initial apparent viscosity ( η initial), degree of swelling, birefringence changes, and leaching of starch and amylose. The η initial measurements provided an objective and analytical means of determining the degree of pressure-induced gelatinization of starch. Both normal and waxy rice starches exhibited sigmoidal-shaped pressure-induced gelatinization curves. The degree of gelatinization was dependent on the type of starch, the pressure, the temperature, and the duration of treatment. Different combinations of these factors could result in the same degree of gelatinization. There was a linear correlation between the degree of swelling and η initial. After treatments at ⩾500 MPa, both starches lost all birefringence although they experienced different extents of change in η initial and the degree of swelling.

Influence of calcium fortification on sensory, physical and rheological characteristics of fruit yogurt

There has been great demand of calcium fortified dairy products as they can serve as an ideal vehicle for carrying extra calcium to fulfill the nutritional needs but there is need to generate information on the effect of fortification of calcium on the physical properties of these products. In the present study, the calcium enriched mango yogurt was prepared after fortification of pasteurized yogurt mix with 50 mg Ca/100 ml of calcium lactate, this level selected from a preliminary study of sensory evaluation. Fortification of yogurt with calcium lactate at this level significantly ( P<0.005) increased the water holding capacity (WHC) by 2.99% on 1st day of storage. WHC of calcium fortified fruit yogurt was higher than control fruit yogurt on 7th and 14th day of storage. Measurements performed on slowly stirred samples (flow curves and final apparent viscosity) showed that calcium-enriched fruit yogurt had stronger structures. Calcium fortified fruit yogurt showed less shear thinning behavior as compared to control. Also, apparent viscosity measurements at constant shear rate showed a significantly ( P<0.05) less decrease in initial apparent viscosity in calcium fortified fruit yogurt. However, no statistically significant ( P>0.05) difference was observed in tan δ values of control and calcium fortified fruit yogurt indicating similar nature of bonds involved in the gel structure formation of both the yogurt samples. The more firm structure of the calcium fortified fruit yogurt is thus attributed to the higher extent of colloidal calcium phosphate cross-linking between casein micelles due to increased calcium content by fortification. Also flavor, color, and body and texture scores of control and calcium fortified fruit yogurt did not show any significant difference ( P>0.05).

Electrorheological Properties of Phosphoric Ester Cellulose Electrorheological Suspensions with Activation of Dispersed Particles

The electrorheological (ER) behavior of activated ER suspensions in silicone oil of phosphoric ester cellulose powder (average particle size : 17.77 μm) was investigated at room temperature with electric fields up to 2.5 kV mm-1. For increasing ER effect of ER suspensions, activating effect of dispersed particles, phosphoric ester cellulose, on ER activity was studied. Anhydrous ER suspensions based on phosphoric ester cellulose particles made from cellulose treated in chemical solution of 2 M phosphoric acid and 4 M urea, heated at 150 °C and crushed were measured. After activating the dispersed particles in anhydrous ER suspensions at 120 °C, analysis of the dispersed phosphoric ester cellulose particles was made. ER properties of ER suspensions such as dielectric constant, current density, electrical conductivity, and rheological properties were studied. Activating of dispersed particles had large influence on ER activities of anhydrous ER suspensions based on phosphoric ester cellulose. With activation time, particle size, and number of dispersed particles per unit volume, electrical properties, dynamic yield stress on electric field, initial apparent viscosity (η0), and ER effect (τA/τ0) of phosphoric ester cellulose ER suspensions increased at 120 °C.

Effect of Milk Preacidification on Low Fat Mozzarella Cheese: II. Chemical and Functional Properties During Storage

The effect of milk preacidification on cheese manufacturing, chemical properties, and functional properties of low fat Mozzarella cheese was determined. Four vats of cheese were made in 1 d using no preacidification (control), preacidification to pH 6.0 and pH 5.8 with acetic acid, and preacidification to pH 5.8 with citric acid. This process was replicated four times. Modifications in the typical Mozzarella manufacturing procedures were necessary to accommodate milk preacidification. The chemical composition of the cheeses was similar among the treatments, except the calcium content and calcium as a percentage of protein were lower in the preacidified treatments. During refrigerated storage, the chemical and functional properties of low fat Mozzarella were affected the most by milk preacidification to pH 5.8 with citric acid. The amount of expressible serum, unmelted cheese whiteness, initial unmelted hardness, and initial apparent viscosity were lower with preacidification. The reduction in initial unmelted cheese hardness and initial apparent viscosity in the pH 5.8 citric treatments represents an improvement in the quality of low fat Mozzarella cheese that allows the cheese to have better pizza bake characteristics with shorter time of refrigerated storage.

The Effect of Activation Time of Phosphoric Ester Cellulose Particles on the Electrorheological Properties of Anhydrous ER Fluids

The electrorheological (ER) behavior of suspensions in silicone oil of phosphoric ester cellulose powder (average particle size: 17.77 μm) was investigated at room temperature with electric fields up to 2.5 kV/mm. For development of anhydrous ER fluids using at wide temperature range, it was sought the effect of activation time of phosphoric ester cellulose particles on the ER activities. Anhydrous ER fluids based on the phosphoric ester cellulose particles made from cellulose particles treating in chemical solution of 2M phosphoric acid and 4M urea and heating at 150°C were measured. After activating the phosphoric ester cellulose anhydrous ER fluids at 120°C, not only analysis of dispersing cellulose particles but also electroroheological characteristics of ER fluids such as dielectric constant, current density, electrical conductivity and rheological properties were studied. Activation time had a large influence to ER properties of anhydrous ER fluids based on phosphoric ester cellulose. As the activation time went by, particle size and number of dispersing particles, electrical properties, dynamic yield stress on electric field, initial apparent viscosity (η0) and electrorheological effect (τA/τ0) of phosphoric ester cellulose ER fluids increased with increasing activation time at 120°C till activation time over 5 hours.