scholarly journals Relationship between Structure and Rheology of Hydrogels for Various Applications

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 255
Author(s):  
Gorjan Stojkov ◽  
Zafarjon Niyazov ◽  
Francesco Picchioni ◽  
Ranjita K. Bose

Hydrogels have gained a lot of attention with their widespread use in different industrial applications. The versatility in the synthesis and the nature of the precursor reactants allow for a varying range of hydrogels with different mechanical and rheological properties. Understanding of the rheological behavior and the relationship between the chemical structure and the resulting properties is crucial, and is the focus of this review. Specifically, we include detailed discussion on the correlation between the rheological characteristics of hydrogels and their possible applications. Different rheological tests such as time, temperature and frequency sweep, among others, are described and the results of those tests are reported. The most prevalent applications of hydrogels are also discussed.

2020 ◽  
Vol 29 (12) ◽  
pp. 52-58
Author(s):  
E.P. Meleshkina ◽  
◽  
S.N. Kolomiets ◽  
A.S. Cheskidova ◽  
◽  
...  

Objectively and reliably determined indicators of rheological properties of the dough were identified using the alveograph device to create a system of classifications of wheat and flour from it for the intended purpose in the future. The analysis of the relationship of standardized quality indicators, as well as newly developed indicators for identifying them, differentiating the quality of wheat flour for the intended purpose, i.e. for finished products. To do this, we use mathematical statistics methods.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2502
Author(s):  
Bogumiła Urbańska ◽  
Hanna Kowalska ◽  
Karolina Szulc ◽  
Małgorzata Ziarno ◽  
Irina Pochitskaya ◽  
...  

The content of polyphenols in chocolate depends on many factors related to the properties of raw material and manufacturing parameters. The trend toward developing chocolates made from unroasted cocoa beans encourages research in this area. In addition, modern customers attach great importance to how the food they consume benefits their bodies. One such benefit that consumers value is the preservation of natural antioxidant compounds in food products (e.g., polyphenols). Therefore, in our study we attempted to determine the relationship between variable parameters at the conching stage (i.e., temperature and time of) and the content of dominant polyphenols (i.e.,catechins, epicatechins, and procyanidin B2) in chocolate milk mass (CMM) obtained from unroasted cocoa beans. Increasing the conching temperature from 50 to 60 °C decreased the content of three basic flavan-3-ols. The highest number of these compounds was determined when the process was carried out at 50 °C. However, the time that caused the least degradation of these compounds differed. For catechin, it was 2 h; for epicatechin it was 1 h; and for procyanidin it was 3 h. The influence of both the temperature and conching time on the rheological properties of chocolate milk mass was demonstrated. At 50 °C, the viscosity and the yield stress of the conched mass showed its highest value.


2019 ◽  
Vol 71 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Jerzy Piecuch ◽  
Anna Mertas ◽  
Alicja Nowowiejska–Wiewiora ◽  
Robert Zurawel ◽  
Sławomir Gregorczyn ◽  
...  

2020 ◽  
Vol 30 (1) ◽  
pp. 130-137
Author(s):  
Hengxiao Yang ◽  
Qimian Mo ◽  
Hengyu Lu ◽  
Shixun Zhang ◽  
Wei Cao ◽  
...  

AbstractTo describe uncured rubber melt flow, a modified Phan–Thien–Tanner (PTT) model was proposed to characterize the rheological behavior and a viscoelastic one-dimensional flow theory was established in terms of incompressible fluid. The corresponding numerical method was constructed to determine the solution. Rotational rheological experiments were conducted to validate the proposed model. The influence of the parameters in the constitutive model was investigated by comparing the calculated and experimental viscosity to determine the most suitable parameters. The uncured rubber viscosity was 3–4 orders larger than that of plastic and did not have a visible Newtonian region. Compared with the Cross-Williams-Landel-Ferry (Cross-WLF) and original PTT models, the modified PTT model can describe the rheological characteristics in the entire shear-rate region if the parameters are set correctly.


1982 ◽  
Vol 1 (1) ◽  
pp. 24-27 ◽  
Author(s):  
I. Taitl

Fired resistors exhibit variations which are minimised by abrasive and laser trimming. The latter may cause unstable behaviour which is further aggravated by thermal shock. The chemical structure of a thick film resistor is analysed with respect to mechanical stress, and the theoretical conclusion that the coefficient of thermal expansion of the resistor should be equal to or smaller than that of the substrate is verified experimentally. The thermal behaviour of ruthenium dioxide is examined and a range of CTE values are determined for materials of varying chemical composition. The relationship between CTE and post laser trimming stability is demonstrated on four thick film resistors which differ in thermal expansion. It is pointed out that formulations with high metallic content can absorb tensile stress by elastic deformation, thus minimising the formation or propagation of laser induced cracks.


TECHNOLOGY ◽  
2015 ◽  
Vol 03 (02n03) ◽  
pp. 80-83
Author(s):  
Mark Polikovsky ◽  
Eshel Ben-Jacob ◽  
Alin Finkelshtein

Cellulose hydrolysis has many industrial applications such as biofuel production, food, paper and textile manufacture. Here, we present a novel approach to cellulose hydrolysis using a consortium of motile bacteria, Paenibacillus vortex, that can swarm on solid medium carrying a non-motile recombinant E. coli cargo strain expressing the β-glucosidase and cellulase genes that facilitate the hydrolysis of cellulose. These two species cooperate; the relationship is mutually beneficial: the E. coli is dispersed over long distances, while the P. vortex bacteria gain from the supply of cellulose degradation products. This enables the use of such consortia in this area of biotechnology.


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