scholarly journals FEATURES OF PHYSICAL AND MECHANICAL PARAMETERS OF ACRYLIC PLASTICS AFTER FULLERENE COATING

2020 ◽  
Vol 73 (6) ◽  
pp. 1097-1102
Author(s):  
Bohdan Yu. Sylenko ◽  
Valentyn M. Dvornyk ◽  
Yurii I. Sylenko ◽  
Maryna V. Khrebor ◽  
Tetiana A. Khmil ◽  
...  

The aim of the research is to study the physical and mechanical parameters of the bases in removable laminar dentures after modification of their surface. Materials and methods: the studied samples were divided into two groups (group I – acrylic plastics, and group II – acrylic plastics with fullerene С60 nanocoating), 50 samples in each group. The coefficients of water absorption, water solubility, microhardness and deformation characteristics of materials were studied. Results and conclusions: The material covered with fullerene С60 has a lower coefficient of water absorption and water solubility, which amounted to 0.55% and 0.23% respectively, from the initial weight of samples, as compared with acrylic plastics without coating (0.71% and 034%, respectively). The strength parameters of samples of group ІІ were higher by 13.5% as compared to group І. The given results of water absorption and water-solubility show that acrylic plastics with fullerene С60 molecules coating has a lower coefficient of water absorption and water solubility, in comparison with acrylic plastics without coating. This indicates a higher degree of resistance to biodegradation of the modified surface material, in turn reducing the washing-out of residual monomer from the denture, which directly improves the strength parameters of the acrylic plastics and can prevent the development of denture stomatitis.

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 485
Author(s):  
Vera Schmid ◽  
Antje Trabert ◽  
Judith (Schäfer) Keller ◽  
Mirko Bunzel ◽  
Heike P. Karbstein ◽  
...  

Food by-products can be used as natural and sustainable food ingredients. However, a modification is needed to improve the technofunctional properties according to the specific needs of designated applications. A lab-scale twin-screw extruder was used to process enzymatically treated apple pomace from commercial fruit juice production. To vary the range of the thermomechanical treatment, various screw speeds (200, 600, 1000 min−1), and screw configurations were applied to the raw material. Detailed chemical and functional analyses were performed to develop a comprehensive understanding of the impact of the extrusion processing on apple pomace composition and technofunctional properties as well as structures of individual polymers. Extrusion at moderate thermomechanical conditions increased the water absorption, swelling, and viscosity of the material. An increase in thermomechanical stress resulted in a higher water solubility index, but negatively affected the water absorption index, viscosity, and swelling. Scanning electron microscopy showed an extrusion-processing-related disruption of the cell wall. Dietary fiber analysis revealed an increase of soluble dietary fiber from 12.6 to 17.2 g/100 g dry matter at maximum thermo-mechanical treatment. Dietary fiber polysaccharide analysis demonstrated compositional changes, mainly in the insoluble dietary fiber fraction. In short, pectin polysaccharides seem to be susceptible to thermo-mechanical stress, especially arabinans as neutral side chains of rhamnogalacturonan I.


2014 ◽  
Vol 3 (6) ◽  
pp. 107 ◽  
Author(s):  
Sushil K. Singh ◽  
K. Muthukumarappan

<p>Nutritionally balanced ingredient blends for catla (<em>Catla catla</em>), belonging to the family Cyprinidae, were extruded using single screw extruder. The extrusion was carried out at five levels of soy white flakes content (21%, 29%, 40%, 52%, and 59% db), five levels of moisture content (15, 19, 25, 31, and 35% db) and five levels of barrel temperature (100, 110, 125, 140, and 150 ºC) using three different die nozzles (having L/D ratios 3.33, 5.83, and 7.25). Blends with net protein content of 32.5% contains soy white flakes, along with high protein distillers dried grains (HP-DDG), corn flour, corn gluten meal, fish meal, vitamin, and mineral mix. A central composite rotatable design (CCRD) and  response surface methodology (RSM) was used to investigate the significance of independent and interaction effects of the extrusion process variables on the extrudates physical properties namely pellet durability index, bulk density, water absorption and solubility indices and expansion ratio. Quadratic polynomial regression equations were developed to correlate the product responses and process variables as well as to obtain the response surfaces plots. The independent variables had significant (<em>P </em>&lt; 0.05) effects on physical properties of extrudates: (i) higher soy white flakes content increased the pellet durability index and water absorption index, but decreased the water solubility index, (ii) higher temperature decreased pellet durability index, bulk density and water solubility index, (iii) increased L/D ratio from 3.33 to 7.25 increased the pellet durability index, expansion ratio but decreased the bulk density of the extrudates.</p>


Author(s):  
Gbocho Serge Elvis Ekissi ◽  
Jacques Yapi Achy ◽  
Martin Tanoh Kouadio ◽  
Bedel Jean Fagbohoun ◽  
Lucien Patrice Kouamé

Impacts of cooking times (steaming and cooking on embers) on some physico-functional parameters of yam (D. bulbifera) flours cv Dougou-won were determined during 10, 20 and 30 min. Results showed that steaming and cooking on embers increased significantly (P <0.05) the dispersibility (D), water absorption capacity (WAC), paste clarity (PC), water solubility index (WSI), swelling power (SP), least gelation capacity (LGC) and solubility (S) but decreased significantly (P <0.05) foam capacity (FC), wettability (W) and foam stability (FS) of flours (D. bulbifera) cv Dougou-won. Steaming increased significantly (P <0.05) oils absorption capacity (OAC) and bulk density (BD). However, cooking on embers decreased significantly (P <0.05) oils absorption capacity (OAC) but not affected significantly (P <0.05) bulk density (BD). The steaming time (30 min) is recommended to considerably influence the physico-functional parameters of the yam (D. bulbifera) flours cv Dougou-won.


2015 ◽  
Vol 16 (SE) ◽  
pp. 519-524
Author(s):  
Neda Hashemi ◽  
Sayed Ali Mortazavi ◽  
Elnaz Milani ◽  
Faride Tabatabaie Yazdi

In recent years, the demand for snacks with optimal functional and nutritional properties has a dramatic increased; hence researching in this regard is considered as an essential task. Almond, is one of the nuts kernel and an important source of nutrients, especially fats, fiber, antioxidants, vitamins and minerals such as iron and calcium. Using this seeds nut in expanded products not only improves the nutritional properties but also it causes to produce a product with optimal functional features. As the screw rate and humidity level have a great effect on the properties of extruded products. In this study, defatted almond flour –corn flour blends (20 - 80) were extruded in a co-rotating twin-screw extruder. Response surface methodology using a central composite design was used to evaluate the effects of independent variables, namely screw rate (120–220 rpm) and humidity level (12–16%) on functional properties (water absorption index, water solubility index and oil absorption index). Based on the process optimization maximum water absorption is 6.54085, water solubility is 25.6472 and oil absorption is 3.09778 that was belong to the production of screw rate 209.17 rpm and the 14% humidity.


2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Xiabing Liu ◽  
Shaohui He ◽  
Dahai Wang

Discontinuous defect in the rockmass is a key influential factor in controlling the strength behavior, and how to estimate the anisotropic strength and scale effect on the defected rockmass is the remaining challenging focus in engineering application. In the present study, intact tuff samples cored from the Xiabeishan tunnel engineering in situ are conducted by experiment tests (i.e., uniaxial compression test, triaxial compression test, and Brazilian tensile test) to obtain the corresponding mechanical parameters. Results from the numerical simulations using the particle flow code (PFC) by the flat-jointed model (FJM) are performed to match the macroparameters from experimental results. It is observed that numerical results have good agreement with the macroscopic mechanical parameters of intact samples including UCS, BTS, triaxial compression strength, and corresponding deformation parameters. Finally, a series of uniaxial and confining compression tests are conducted by using a synthetic rockmass (SRM) method which is coupled with the discrete element method (DEM) and discrete fracture network (DFN). Then, the anisotropy and scale effects on the strength characteristics of the defected rockmass are investigated. The results show that defects have a vital effect on the failure mode and strength behavior of the rockmass in the research region. The strength parameters are changed with the specimen size. The REV size of the considered defected rockmass is regarded as 5 × 10 m, and this size is also influenced by the confinement level. The anisotropy of macroscopic strength parameters is found in the considered defected rockmass, whose stress-strain curves and failure modes are also discussed.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ritika Puri ◽  
Balmeet Singh Gill ◽  
Yogesh Khetra

Consumer preferences in east Asian part of the world pave the way for consumption of lotus stem starch (LSS) in preparations such as breakfast meals, fast foods, and traditional confectioneries. The present study envisaged the investigation and optimization of additives, that is, acacia gum, sodium chloride (NaCl), and sucrose, on water absorption (WA), water absorption index (WAI), and water solubility index (WSI) of LSS employing response surface methodology (RSM). Acacia gum resulted in increased water uptake and swelling of starch; however, NaCl reduced the swelling power of starch by making water unavailable to starch and also due to starch-ion electrostatic interaction. Sucrose restricted the water absorption by binding free water and decreased amylose leaching by building bridges with starch chains and thus forming rigid structure.


2012 ◽  
Vol 204-208 ◽  
pp. 727-731
Author(s):  
Yuan Zhao ◽  
Liang Qing Wang ◽  
Ye Liang

Deformation modulus plays an important role in evaluating slope stability of rock mass and conducting the geotechnical engineering design. Based on the research of geological properties, physical and mechanical parameters of predominant rock mass types for different formations from Zhongxian to Wuhan, China, deformation modulus values of gas pipeline area were estimated by using rock mass classification method in this paper. Comparisons were made amongst different formulas based on GSI, RMR and Q methods to suggest range values of deformation modulus for predominant rock mass types of different formations which gives instructions to estimate strength parameters of rock masses for similar projects.


Author(s):  
Navneet Kumar ◽  
B. C. Sarkar ◽  
Harish Kumar Sharma

Dehydrated carrot pomace was added in different proportions (10-30%) to rice flour. The formulation was extruded at different moisture content (17-21%), screw speed (270-310 rpm) and die temperature (110-130°C). The experimental combinations were decided based on central composite rotatable design for four variables at five levels of each variable. The lateral expansion, bulk density, water absorption index, water solubility index, hardness and sensory characteristics were measured as responses. Significant regression models were established with the coefficient of determination, R² greater than 0.70. The results indicated that pomace proportion, screw speed and temperature significantly influenced (P<0.10) lateral expansion; moisture content and screw speed for bulk density; pomace proportion and temperature for water absorption index and water solubility index, pomace proportion, screw speed and temperature for hardness and screw speed for sensory score. The compromised optimum condition obtained by numerical integration for development of extrudates were: carrot pomace of 11.75% in rice flour, moisture content 19.92%, screw speed 249.1 rpm and die temperature 114.3°C. Sensory evaluation revealed that carrot pomace could be incorporated into ready-to-eat expanded products upto the level of 11.75%.


Author(s):  
Nikhil D. Solanke Pradeep P. Thorat ◽  
Jayashri Ughade

The purpose of this study is to determine the quality of chickpea and black gram flour used in preparation of traditional products. As the study of physical properties of flour, both chickpea as well as black gram flour shows higher in bulk density. Water absorption index show lower level of both chickpea as well as black gram flour and water solubility index shows both chickpea as well as black gram flour in between bulk density and water absorption index. While the functional properties of flour, water absorption capacity lower for chickpea flour but higher oil absorption capacity. Higher the water absorption capacity for black gram flour and lower the oil absorption capacity for black gram. This concluded that bulk density for both chickpea flour and black gram is highest while oil absorption capacity is lower in both chickpea flour and black gram flours.


2019 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Nesho Toshkov ◽  
Apostol Simitchiev ◽  
Vencislav Nenov

Extrusion of corn semolina milled with cocoa shells using a single screw extruder “BRABENDER 20 DN” was carried out. Full factorial experimental 22 was used to investigate the effects of the quantity of cocoa shells and moisture of the material on the water absorption index (WAI) and water solubility index (WSI). Working screw speed and feed screw speed were fixed at 200 and 40 rpm, respectively. Compression ratio of the screw was fixed at 4:1. Temperatures of the first, second and third zone were 150, 155 and 160 °C. Water absorption index values range were between 6.71 and 7.6 g/g and the water solubility index between 25.38 and 35.33 %. The increase in moisture content and quantity of cocoa shells leads to an increase in water absorption index and a decrease in water solubility index. Practical applications: Cocoa shells in an amount of up to 10% can be used in the production of extrudates by mixing with corn semolina. Water absorption index values range between 6.71 and 7.6 g/g and the water solubility index between 25.38 and 35.33 %. The resulting regression models can be used to optimize the process. In general, results show that cocoa shells can be mixed with corn semolina for the production of extrudates, which allows us to recommend extrusion processing of cocoa shells as an alternative technology in utilization processing of raw cocoa materials.


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