scholarly journals Modelling the Relations of Rheological Characteristics with Composition of Plaster Mortar

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 371
Author(s):  
Khrystyna Moskalova ◽  
Tatiana Lyashenko ◽  
Aleksej Aniskin
Keyword(s):  
Ethyl Cellulose ◽  
Effective Viscosity ◽  
Cement Hydration ◽  
Ethylene Vinyl Acetate ◽  
Rheological Characteristics ◽  
Expanded Perlite ◽  
Rotational Viscometer ◽  
Information Set ◽  
The Individual ◽  
Composition Factors

The rheological properties of fresh plaster mortars, with varied contents of porous fillers and polymer admixtures, have been studied. The quantities of fine limestone and expanded perlite, and dosages of methyl hydroxy ethyl cellulose and ethylene vinyl acetate were varied in the experiment. Effective viscosity (at a shear rate from 0.045 to 5.705 s−1) and the thixotropy of the mixes were determined with rotational viscometer for 18 compositions (according to the design of the experiment). Each of the 18 viscosity curves were described with the Ostwald–de-Waele equation. The Experimental–Statistical models describing the dependencies of the parameters of the rheological model and of mix thixotropy on the composition factors were built on the obtained data. ES-models have allowed the individual and synergetic effects of mix components on the rheological characteristics to be evaluated. The expanded perlite powder can increase the viscosity by two times, probably due to its pozzolanic effect increasing the content of the CSH phase during cement hydration. The thixotropy can be increased by the quantity of limestone. The computational experiments with ES-models have made it possible for the information set, without a noticeable interrelation between rheological characteristics, to be stratified into subsets, in which such interrelations differ significantly.

scholarly journals Psychosocial and Diet-Related Lifestyle Clusters in Overweight and Obesity

2021 ◽  
Vol 18 (12) ◽  
pp. 6461
Author(s):  
Débora Godoy-Izquierdo ◽  
Raquel Lara ◽  
Adelaida Ogallar ◽  
Alejandra Rodríguez-Tadeo ◽  
María J. Ramírez ◽  
...  
Keyword(s):  
Adult Population ◽  
Well Being ◽  
Overweight And Obesity ◽  
Excess Weight ◽  
Convenience Sample ◽  
Excessive Weight ◽  
Self Reports ◽  
The Individual ◽  
Composition Factors ◽  
Overweight Or Obesity

This study explored intraindividual multidimensional profiles integrating psychosocial factors, namely, body image and satisfaction, weight-related self-stigma, positivity, and happiness, and behavioural-lifestyle factors, namely, adherence to a healthy diet, among Spanish adults with overweight or obesity. We further aimed to investigate the association of excess weight (i.e., measured body mass index, BMI) with the abovementioned multidimensional configurations. A convenience sample of 100 adult individuals (60% females) with excessive weight (69% overweight; 31% obesity) was recruited. They completed self-reports regarding the study variables, and their weight and height were measured. With a perspective centered on the individual, a cluster analysis was performed. Three distinct intraindividual psychosocial and diet-related profiles were identified: a group of healthy individuals with excess weight (46%); a group of individuals who were negatively affected by their excessive weight and showed the most distressed profile (18%); and a group of dysfunctional individuals who seemed to be excessively unrealistic and optimistic regarding their excessive weight and unhealthy lifestyles, but were troubled by their weight (36%). Furthermore, individuals in the affected cluster had higher obesity (mean BMI ± SD = 32.1 ± 3.7) than those in the clusters of healthy (28.0 ± 3.0) and dysfunctional individuals (28.1 ± 3.3) (p < 0.05). The results showed that there are specific psychosocial and lifestyle profiles in the adult population with excess weight and that there are relationships among psychological, behavioural, and body-composition factors. For clinical application purposes, it is important to account for the heterogeneity within individuals who are obese and to individualize the interventions, with a focus from weight change to the individual’s overall well-being.

Dispersion Flow in Microchannels

2012 ◽  
Author(s):  
Alfir T. Akhmetov ◽  
Marat V. Mavletov ◽  
Sergey P. Sametov ◽  
Artur A. Rakhimov ◽  
Azat A. Valiev ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Effective Viscosity ◽  
Complex Structure ◽  
Experimental Investigations ◽  
Dispersed Phase ◽  
Rheological Characteristics ◽  
Dense Structure ◽  
The Third ◽  
Dynamic Blocking ◽  
Oil Emulsions

The work is devoted to experimental investigations of the features of flow of dispersions in microchannels. The paper consists of three parts. In the first part the flow of emulsions in smooth contracting cylindrical microchannels is investigated. It is received that a significant role at dynamic blocking of channels is played by the inclusions comparable by size to the diameter of a narrowing. This is in spite of the fact that their influence on the change of a flow rate of emulsion before blocking is insignificant. In the second part the generation of emulsion in a complex structure of microchannels (micromodels) when water is displaced by composition of hydrocarbon with surfactants is investigated. The experimental dependences of the rheological characteristics of emulsions based on the composition of SAS and water at different concentrations of the aqueous phase can explain blocking of a porous structure by generated emulsion. In the third part a comparison of flow of water-in-oil emulsions with the suspension which was obtained by freezing the microdroplets of the aqueous phase of emulsions was studied. It was found that the blocking of suspension is not as complete as in the case of emulsion. It is explained by deformation of the droplets and by formation of a dense structure, as opposed to suspension of beads, through which hydrocarbon phase is filtered. A small increase in effective viscosity due to solidification of freezing droplets of the dispersed phase was found.

scholarly journals Karakteristik Reologi Komposit Serbuk Cangkang Kemiri dan Poliuretan

2019 ◽  
Vol 4 (1) ◽  
pp. 1-6
Author(s):  
Yovial Mahyoedin ◽  
Kurnia Harlina Dewi ◽  
Wenny Marthiana ◽  
Rizky Arman ◽  
Ridho Azhari
Keyword(s):  
Particle Size ◽  
Taguchi Method ◽  
Rheological Characteristics ◽  
Rotational Viscometer ◽  
Stirring Time ◽  
Mechanical Mixer

AbstrakPenelitian ini bertujuan menentukan karakteristik reologi komposit serbuk cangkang kemiri (SCK) berukuran 45µm<d<75µm dan resin Poliuretan (PU) dengan komposisi bervariasi, yaitu 5%:95%, 10%:90%, 15%:85%. Pencampuran SCK dan PU dilakukan dengan mechanical mixer dengan kecepatan dan lama pengadukan masing-masing 10, 15 dan 20 menit dan 100, 200 dan 250 rpm. Reologi komposit diperoleh dengan pengujian rotational viscometer dan dioptimasi dengan metoda Taguchi. Penelitian menunjukkan viskositas terkecil 218,66 mPa.s, ditemukan pada komposit dengan komposisi 5% 95%, waktu pengadukan 15 menit dan kecepatan pengadukan 100 rpm.  Kata kunci: Serbuk cangkang kemiri, Poliuretan, Viskositas, Reologi.  Abstract This study aimed to determine the composite rheological characteristics of candlenut shells (SCK) with particle size of 45µm <d <75µm and polyurethane (PU) resins with varying compositions, namely 5%: 95%, 10%: 90%, 15%: 85%. Mixing of SCK and PU is carried out using mechanical mixers with a speed and stirring time of 10, 15 and 20 minutes and 100, 200 and 250 rpm, respectively. Composite rheology was obtained by rotational viscometer testing and optimized by the Taguchi method. The results showed the smallest viscosity of 218.66 mPa.s, found in composites with a composition of 5% 95%, stirring time of 15 minutes and stirring speed of 100 rpm. Keywords: candlenut shell, polyurethane, viscosity, rheology

scholarly journals Psychosocial Resources and Diet-Related Lifestyle in Overweight and Obesity: A Cluster-Based Study

2021 ◽  
Author(s):  
Débora Godoy-Izquierdo ◽  
Raquel Lara ◽  
Adelaida Ogallar ◽  
Alejandra Rodríguez-Tadeo ◽  
María J. Ramírez ◽  
...  
Keyword(s):  
Adult Population ◽  
Well Being ◽  
Overweight And Obesity ◽  
Excess Weight ◽  
Convenience Sample ◽  
Excessive Weight ◽  
Self Reports ◽  
The Individual ◽  
Composition Factors ◽  
Overweight Or Obesity

This study explored intraindividual multidimensional profiles integrating psychosocial factors, namely, body image and satisfaction, weight-related self-stigma, positivity, and happiness, and behavioural-lifestyle factors, namely, adherence to a healthy diet, among Spanish adults with overweight or obesity. We further aimed to investigate the association of excess weight (i.e., measured body mass index, BMI) with the abovementioned multidimensional configurations. A convenience sample of adult individuals with excessive weight completed self-reports regarding the study variables, and their weight and height were measured. With a perspective centered on the individual, a cluster analysis established three distinct intraindividual psychosocial and diet-related profiles: a group of healthy individuals with excess weight; a group of individuals who were negatively affected by their excessive weight and showed the most distressed profile; and a group of dysfunctional individuals who seemed to be excessively unrealistic and optimistic regarding their excessive weight and unhealthy lifestyles. Furthermore, individuals in the affected cluster had higher obesity. The results showed that there are specific psychosocial and lifestyle profiles in the adult population with excess weight and that there are relationships among psychological, behavioural, and body-composition factors. For clinical application purposes, it is important to account for the heterogeneity within individuals who are obese and to individualize the interventions, with a focus from weight change to individual's overall well-being.

scholarly journals Discrete-Impulse Energy Supply in Milk and Dairy Products Processing

2021 ◽  
Author(s):  
Pawel Droździel ◽  
Tetiana Vitenko ◽  
Viktor Voroshchuk ◽  
Sergiy Narizhnyy ◽  
Olha Snizhko
Keyword(s):  
Milk Fat ◽  
Dairy Products ◽  
Energy Supply ◽  
Effective Viscosity ◽  
Rheological Characteristics ◽  
Cream Cheese ◽  
Viscosity Change ◽  
Multicomponent Media ◽  
Centrifugation Method ◽  
Milk And Dairy Products

The basis of the discrete-impulse energy supply (DIES) concept is the efficient use of supplied energy. The references describe in detail the general principles of DIES, examine the energy and thermodynamic aspects and the main mechanisms of intensification that can be initiated on the basis of this principle. DIES mechanisms conveniently can be divided into hard and soft ones. The former should be used to stimulate hydromechanical processes, and the latter to accelerate the processes of phase heat and mass transfer, or for the purpose of intensive mixing of multicomponent media. The authors have studied the possibility of using DIES to intensify the hydromechanical processes, in particular emulsification of milk fat (homogenization of milk, preparation of spreads), processing of cream cheese masses. Objects of research were whole non-homogenized milk, fat emulsions, cream cheese mass. In order to evaluate the efficiency of milk homogenization the homogenization coefficient change was studied, which was determined by centrifugation method as the most affordable and accurate one. Emulsions were evaluated according to the degree of destabilization, resistance and dispersion of the fat phase. The rheological characteristics of cheese masses were evaluated by the effective viscosity change.

scholarly journals The Design of Individual Orthopedic Insoles for the Patients with Diabetic Foot Using Integral Curves to Describe the Plantar Over-Pressure Areas

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Merab Shalamberidze ◽  
Zaza Sokhadze ◽  
Malvina Tatvidze
Keyword(s):  
Diabetic Foot ◽  
Mechanical Damage ◽  
Ethylene Vinyl Acetate ◽  
Numerical Control ◽  
Hard Material ◽  
Singular Boundary ◽  
Mathematical Algorithm ◽  
Integral Curves ◽  
Orthopedic Insoles ◽  
The Individual

Identification of over-pressure areas in the plantar side of the foot in patients with diabetic foot and reduction of plantar pressure play a major role in clinical practice. The use of individual orthopedic insoles is essential to reduce the over-pressure. The aim of the present study is to mark the over-pressure areas of the plantar part of the foot on a pedogram and describe them with high accuracy using a mathematical research method. The locally over-pressured areas with calluses formed due to repeated injuries were identified on the patients’ pedograms. The geometric shapes of the over-pressure areas were described by means of the integral curves of the solutions to Dirichlet singular boundary differential equations. Based on the mathematical algorithm describing those curves, the computer programs were developed. The individual orthopedic insoles were produced on a computer numerical control milling machine considering the locally over-pressured areas. The ethylene vinyl acetate polymers of different degrees of hardness were used to produce the individual orthopedic insoles. For the over-pressure areas, a soft material with a hardness of 20 Shore A was used, which reduces the pressure on the plantar side of the foot and increases the contact area. A relatively hard material with a hardness of 40 Shore A was used as the main frame, which imparts the stability of shape to the insole and increases its wear life. The individual orthopedic insoles produced by means of such technology effectively reduce the pressure on the plantar side of the foot and protect the foot from mechanical damage, which is important for the treatment of the diabetic foot.

scholarly journals Preparation and Rheological Characteristics of Ethylene‐Vinyl Acetate Copolymer/Organoclay Nanocomposites

2007 ◽  
Vol 46 (2) ◽  
pp. 261-273 ◽  
Author(s):  
Hyung Min Lee ◽  
Bong Jun Park ◽  
Hyoung Jin Choi ◽  
Rahul Kumar Gupta ◽  
Sati N. Bhattachary
Keyword(s):  
Vinyl Acetate ◽  
Ethylene Vinyl Acetate ◽  
Rheological Characteristics ◽  
Acetate Copolymer ◽  
Ethylene Vinyl Acetate Copolymer

scholarly journals Experimental Analysis of Electrical Conductivity of the 3D Printed Graphene

2019 ◽  
Vol 8 (6) ◽  
pp. 3316-3321
Keyword(s):  
Electrical Conductivity ◽  
Equivalent Circuit ◽  
Piezoelectric Material ◽  
Experimental Analysis ◽  
Ethyl Cellulose ◽  
Material System ◽  
Direct Ink Writing ◽  
3D Printed ◽  
The Individual ◽  
Processing Steps

To develop a 3D printed material system for extracting the electrical conductivity of the piezoelectric material, to fabricate the integrated piezoelectric prototype and it’s always have a good availability with the more number of variety of materials for making with special characteristics. This paper introduces with direct ink writing method for printing the piezoelectric material by using multi materials such as terphinal, ethyl cellulose, methanol and graphene. The materials and processing steps for the manufacturing the 3d printed piezoelectric component, the individual material characteristics and the equivalent circuit is provided. Electrical Conductivity analysis on the 3D printed piezoelectric done with the above mentioned material and the result has been discussed by using the four point probe method.

The flow-to-sliding transition in crystalline magma

2020 ◽  
Author(s):  
Zhipeng Qin ◽  
Jenny Suckale
Keyword(s):  
Effective Viscosity ◽  
Large Scale ◽  
Flow Behavior ◽  
Numerical Approach ◽  
Flow Profile ◽  
Rotational Viscometer ◽  
Direct Numerical Method ◽  
Crystal Fraction ◽  
Large Scale Flow ◽  
Dilute Limit

&lt;p&gt;Magmatic flows are rarely, if ever, entirely free of crystals. If these crystals distribute in an approximately homogeneous way, their impact on flow can be captured by defining a suitable effective viscosity for the suspension. A spatially heterogeneous crystal distribution, however, can build up to the degree that the flow behavior of the crystal-bearing magma becomes substantially different from that of a pure melt. One example is the transition from flow to sliding, in which the deformation in the crystalline magma is concentrated almost entirely in a thin interfacial layer as opposed to being distributed in a typical flow profile throughout the domain. The transition is particularly consequential for the large-scale dynamics of the system, because it can be associated with transport rates increasing by orders of magnitudes.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Most conduit models associate the flow-to-sliding transition with a critical crystal fraction, often in the 60% range. Here, we hypothesize that the flow to sliding transition can occur at crystal fraction as low as a few percents under certain conditions. We test our hypothesis by numerically reproducing existing laboratory measurements of the effective viscosity of plagioclase-bearing basalt in a rotational viscometer. We utilize a direct numerical method to resolve the interactions between the crystals and the magmatic melt at the scale of individual interfaces in 2D. Our numerical approach only requires assumptions about the pure phase including the crystal fraction and crystal shape. All phase interactions and their aggregate effect on the flow emerge self-consistently from the simulation itself.&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Our simulations suggest that the behavior of multiphase suspensions at low fluid Reynolds number is highly variable and depends sensitively on the characteristics of the immersed phases and the geometry of the flow domain. We show that there is no meaningful dilute limit in which the phase interactions can be neglected or captured by adjusting the effective rheology of the suspension in a way that removes dependencies on the properties of the immersed phase. Since our models operate at the scale of individual crystals, our model results are testable in both field and laboratory settings. In fact, they suggest that observations of microstructure provide valuable constraints on the large scale flow dynamics at the time. Particularly important is the degree of preferential crystal alignment and the existence of force chains or crystal clusters.&lt;/p&gt;

The use of Modern Interactive Technologies in Shaping the Spatial Thinking of Schoolchildren

2019 ◽  
Vol 7 (1) ◽  
pp. 46-48
Author(s):  
О. Аникеева ◽  
O. Anikeeva
Keyword(s):  
General Education ◽  
Intellectual Development ◽  
Spatial Thinking ◽  
Federal State ◽  
Main Task ◽  
Interactive Technologies ◽  
Information Set ◽  
Education Today ◽  
The Individual ◽  
State Educational

The main task of education today is to learn how to independently obtain information, set problems, look for ways to solve them, be able to analyze the knowledge gained and apply it to solve problems. The degree of learning at all stages of learning determines the level of development of spatial thinking, which is one of the characteristics of the intellectual development of the individual. The article discusses the characteristics of the formation of spatial thinking of schoolchildren. The analysis of the requirements of the Federal State Educational Standards of primary and secondary (complete) general education to knowledge and skills in mathematics has been carried out. A review of modern interactive technologies has been made, allowing to stimulate the development of spatial thinking of schoolchildren since early school.

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