scholarly journals Optimization of Moist and Oven-Dried Bacterial Cellulose Production for Functional Properties

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2088
Author(s):  
Ioana M. Bodea ◽  
Florin I. Beteg ◽  
Carmen R. Pop ◽  
Adriana P. David ◽  
Mircea Cristian Dudescu ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Culture Conditions ◽  
Independent Variables ◽  
Full Factorial Experimental Design ◽  
Experimental Values ◽  
Inoculum Volume ◽  
Two Independent Variables

Bacterial cellulose (BC) is a natural polymer with properties suitable for tissue engineering and possible applications in scaffold production. However, current procedures have limitations in obtaining BC pellicles with the desired structural, physical, and mechanical properties. Thus, this study analyzed the optimal culture conditions of BC membranes and two types of processing: draining and oven-drying. The aim was to obtain BC membranes with properties suitable for a wound dressing material. Two studies were carried out. In the preliminary study, the medium (100 mL) was inoculated with varying volumes (1, 2, 3, 4, and 5 mL) and incubated statically for different periods (3, 6, 9, 12, and 18 days), using a full factorial experimental design. Thickness, uniformity, weight, and yield were evaluated. In the optimization study, a Box–Behnken design was used. Two independent variables were used: inoculum volume (X1: 1, 3, and 5 mL) and fermentation period (X2: 6, 12, and 18 d) to determine the target response variables: thickness, swelling ratio, drug release, fiber diameter, tensile strength, and Young’s modulus for both dry and moist BC membranes. The mathematical modelling of the effect of the two independent variables was performed by response surface methodology (RSM). The obtained models were validated with new experimental values and confirmed for all tested properties, except Young’s modulus of oven-dried BC. Thus, the optimal properties in terms of a scaffold material of the moist BC were obtained with an inoculum volume of 5% (v/v) and 16 d of fermentation. While, for the oven-dried membranes, optimal properties were obtained with a 4% (v/v) and 14 d of fermentation.

scholarly journals Optimization of moist and oven-dried bacterial cellulose production for functional properties

2021 ◽  
Author(s):  
Ioana Maria Bodea ◽  
Florin Ioan Beteg ◽  
Carmen Rodica Pop ◽  
Adriana Paula David ◽  
Mircea Cristian Dudescu ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
Physical And Mechanical Properties ◽  
Young Modulus ◽  
Culture Conditions ◽  
Independent Variables ◽  
Optimization Study ◽  
Full Factorial Experimental Design ◽  
Experimental Values ◽  
Inoculum Volume ◽  
Full Factorial

Abstract Bacterial cellulose (BC) is a natural polymer with properties suitable for tissue engineering and possible applications in scaffold production. However, current procedures have limitations in obtaining BC pellicles with the desired structural, physical, and mechanical properties. Thus, this study analyzed the optimal culture conditions of BC membranes and 2 types of processing: draining and oven-drying. The aim was to obtain BC membranes with properties suitable for a wound dressing material. Two studies were carried out. In the preliminary study the medium (100 mL) was inoculated with varying volumes (1; 2; 3; 4; and 5 mL) and incubated statically for different periods (3; 6; 9; 12; and 18 days), using a full factorial experimental design. Thickness, uniformity, weight, and yield were evaluated. In the optimization study, a Box–Behnken design was used. Two independent variables were used: inoculum volume (X1: 1; 3; and 5 mL) and fermentation period (X2: 6; 12; and 18 d) to determine the target response variables: thickness, swelling ratio, drug release, fiber diameter, Tensile strength, and Young's Modulus for both dry and moist BC membranes. The mathematical modelling of the effect of the 2 independent variables was accomplished by response surface methodology (RSM). The obtained models were validated with new experimental values, and confirmed for all tested properties, except Young Modulus of oven-dried BC. Thus, the optimal properties in terms of a scaffold material of the moist BC were obtained with an inoculum volume of 5% (v/v) and 16 d of fermentation. While, for the oven-dried membranes a 4% (v/v) and 14 d of fermentation.

Effect of Castor Oil Impregnation on the Physical and Mechanical Properties of Bacterial Cellulose

2012 ◽  
Vol 3 (1) ◽  
pp. 13-26
Author(s):  
Myrtha Karina ◽  
Lucia Indrarti ◽  
Rike Yudianti ◽  
Indriyati
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Bacterial Cellulose ◽  
Young’S Modulus ◽  
Castor Oil ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Scanning Electron Micrographs ◽  
Elongation At Break ◽  
Acetone Water

The effect of castor oil on the physical and mechanical properties of bacterial cellulose is described. Bacterial cellulose (BC) was impregnated with 0.5–2% (w/v) castor oil (CO) in acetone–water, providing BCCO films. Scanning electron micrographs revealed that the castor oil penetrated the pores of the bacterial cellulose, resulting in a smoother morphology and enhanced hydrophilicity. Castor oil caused a slight change in crystallinity indices and resulted in reduced tensile strength and Young's modulus but increased elongation at break. A significant reduction in tensile strength and Young's modulus was achieved in BCCO films with 2% castor oil, and there was an improvement in elongation at break and hydrophilicity. Impregnation with castor oil, a biodegradable and safe plasticiser, resulted in less rigid and more ductile composites.

Transverse Young's Moduli and Cell Shapes in Coniferous Early Wood

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Ugai Watanabe ◽  
Minoru Fujita ◽  
Misato Norimoto
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Bending Moment ◽  
Cell Models ◽  
Young’S Moduli ◽  
Cell Shapes ◽  
The Difference ◽  
Square Cells ◽  
Experimental Values ◽  
The Relationship

Summary The relationship between transverse Young's moduli and cell shapes in coniferous early wood was investigated using cell models constructed by two dimensional power spectrum analysis. The calculated values of tangential Young's modulus qualitatively explained the relationship between experimental values and density as well as the difference in experimental values among species. The calculated values of radial Young's modulus for the species having hexagonal cells agreed well with the experimental values, whereas, for the species having square cells, the calculated values were much larger than the experimental values. This result was ascribed to the fact that the bending moment on the radial cell wall of square cell models was calculated to be small. It is suggested that the asymmetrical shape of real wood cells or the behavior of nodes during ell deformation is an important factor in the mechanism of linear elastic deformation of wood cells.

scholarly journals The Elastic Constants of the Single Crystal of the Mg-Zn-Zr-REM Alloy from the Data of the Elastic Anisotropy and the Texture of the Polycrystalline Sheet

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
S. V. San’kova ◽  
N. M. Shkatulyak ◽  
V. V. Usov ◽  
N. A. Volchok
Keyword(s):  
Single Crystals ◽  
Young’S Modulus ◽  
Elastic Constants ◽  
Elastic Anisotropy ◽  
Young's Modulus ◽  
Rare Earth Metals ◽  
Alloy Sheet ◽  
Pole Figures ◽  
Integral Characteristics ◽  
Experimental Values

The measuring of the constants of single-crystals requires the availability of crystals of relatively big size. In this paper the elastic constants of the single crystals of magnesium alloy with zinc, zirconium, and rare earth metals (REM) were determined by means of the experimental anisotropy of Young’s modulus and integral characteristics of texture (ICT), which were found from pole figures. Using these constants the anisotropy of Young’s modulus of alloy sheet ZE10 was calculated. Deviation of calculated values from experimental values did not exceed 2%.

scholarly journals Physical and mechanical rock properties of a heterogeneous volcano; the case of Mount Unzen, Japan

2020 ◽  
Author(s):  
Jackie E. Kendrick ◽  
Lauren N. Schaefer ◽  
Jenny Schauroth ◽  
Andrew F. Bell ◽  
Oliver D. Lamb ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Acoustic Emission ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
B Value ◽  
Coda Wave ◽  
Damage Accrual ◽  
The Impact

Abstract. Volcanoes represent one of the most critical geological settings for hazard modelling due to their propensity to both unpredictably erupt and collapse, even in times of quiescence. Volcanoes are heterogeneous at multiple scales, from porosity which is variably distributed and frequently anisotropic to strata that are laterally discontinuous and commonly pierced by fractures and faults. Due to variable and, at times, intense stress and strain conditions during and post-emplacement, volcanic rocks span an exceptionally wide range of physical and mechanical properties. Understanding the constituent materials' attributes is key to improving the interpretation of hazards posed by the diverse array of volcanic complexes. Here, we examine the spectrum of physical and mechanical properties presented by a single dome-forming eruption at a dacitic volcano, Mount Unzen (Japan) by testing a number of isotropic and anisotropic lavas in tension and compression and using monitored acoustic emission (AE) analysis. The lava dome was erupted as a series of 13 lobes between 1991–1995, and its ongoing instability means much of the volcano and its surroundings remain within an exclusion zone today. During a field campaign in 2015, we selected 4 representative blocks as the focus of this study. The core samples from each block span range in porosity from 9.14 to 42.81 %, and permeability ranges from 1.54 × 10−14 to 2.67 × 10−10 m2 (from 1065 measurements). For a given porosity, sample permeability varies by > 2 orders of magnitude is lower for macroscopically anisotropic samples than isotropic samples of similar porosity. An additional 379 permeability measurements on planar block surfaces ranged from 1.90 × 10−15 to 2.58 × 10−12 m2, with a single block having higher standard deviation and coefficient of variation than a single core. Permeability under confined conditions showed that the lowest permeability samples, whose porosity largely comprises microfractures, are most sensitive to effective pressure. The permeability measurements highlight the importance of both scale and confinement conditions in the description of permeability. The uniaxial compressive strength (UCS) ranges from 13.48 to 47.80 MPa, and tensile strength (UTS) using the Brazilian disc method ranges from 1.30 to 3.70 MPa, with crack-dominated lavas being weaker than vesicle-dominated materials of equivalent porosity. UCS is lower in saturated conditions, whilst the impact of saturation on UTS is variable. UCS is between 6.8 and 17.3 times higher than UTS, with anisotropic samples forming each end member. The Young's modulus of dry samples ranges from 4.49 to 21.59 GPa and is systematically reduced in water-saturated tests. The interrelation of porosity, UCS, UTS and Young's modulus was modelled with good replication of the data. Acceleration of monitored acoustic emission (AE) rates during deformation was assessed by fitting Poisson point process models in a Bayesian framework. An exponential acceleration model closely replicated the tensile strength tests, whilst compressive tests tended to have relatively high early rates of AEs, suggesting failure forecast may be more accurate in tensile regimes, though with shorter warning times. The Gutenberg-Richter b-value has a negative correlation with connected porosity for both UCS and UTS tests which we attribute to different stress intensities caused by differing pore networks. b-value is higher for UTS than UCS, and typically decreases (positive Δb) during tests, with the exception of cataclastic samples in compression. Δb correlates positively with connected porosity in compression, and negatively in tension. Δb using a fixed sampling length may be a more useful metric for monitoring changes in activity at volcanoes than b-value with an arbitrary starting point. Using coda wave interferometry (CWI) we identify velocity reductions during mechanical testing in compression and tension, the magnitude of which is greater in more porous samples in UTS but independent of porosity in UCS, and which scales to both b-value and Δb. Yet, saturation obscures velocity changes caused by evolving material properties, which could mask damage accrual or source migration in water-rich environments such as volcanoes. The results of this study highlight that heterogeneity and anisotropy within a single system not only add uncertainty but also have a defining role in the channelling of fluid flow and localisation of strain that dictate a volcano's hazards and the geophysical indicators we use to interpret them.

Calculation of the parameters of mechanical properties of the heart muscle

2020 ◽  
Vol 12 ◽  
pp. 42-52
Author(s):  
S. A. Muslov ◽  
◽  
A. I. Lotkov ◽  
S. D. Arutyunov ◽  
T. M. Albakova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Elastic Constants ◽  
Heart Muscle ◽  
Human Heart ◽  
Young's Modulus ◽  
Experimental Values ◽  
Two Parameter

A review of studies of the mechanical properties of human and animal heart tissues has been performed. Based on literature data, a form of approximating function is found for the dependence of the Young’s modulus of the ventricles of the human heart on the magnitude of the deformation. The average values of the Young’s modulus and other elastic constants were calculated and compared with the known experimental values. The coefficients C1 and C2 of the two-parameter hyperelastic myocardial Mooney-Rivlin model are calculated.

scholarly journals The investigation of producing bacterial cellulose fibres through hand-spun

2019 ◽  
Vol 131 ◽  
pp. 01052
Author(s):  
Yu Wang
Keyword(s):  
Tensile Strength ◽  
Bacterial Cellulose ◽  
Young’S Modulus ◽  
Filter Cake ◽  
Young's Modulus ◽  
Raw Material ◽  
Cellulose Fibres ◽  
Elongation At Break ◽  
Intermediate States

Nanocellulose fibres can be hand-spun from different intermediate states, such as nanocellulose paper and filter cake, which are made from the BC suspension as well as wet pellicle (WP) and dry pellicle (DP) from BC pellicles. In this study, it can be concluded that increasing the hanging weight can increase the Young’s modulus and the tensile strength of fibres. Nanofibres produced from BC pellicles as raw material have better performance than those made from BC suspension. The best properties obtained from the fibres produced from wet pellicles and suspended to a 100g hanging weight upon drying are Young’s modulus (33.8 GPa), tensile strength (610 MPa) and elongation at break (3.6%).

Influence of B4C, SiC and Si3N4 Additions on Microstructures and Selected Properties of Titanium Nitride Matrix Materials Obtained by HPHT Method

2014 ◽  
Vol 89 ◽  
pp. 109-114
Author(s):  
Jolanta Cyboroń ◽  
Piotr Klimczyk ◽  
Pawel Figiel ◽  
Małgorzata Karolus
Keyword(s):  
Fracture Toughness ◽  
High Pressure ◽  
Phase Composition ◽  
High Temperature ◽  
Titanium Nitride ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Ceramic Phase ◽  
Ultra High Temperature Ceramics

The paper presents the results of the High Pressure and High Temperature (HP-HT) sintering and investigation of Ultra High Temperature Ceramics (UHTC) composites of titanium nitride matrix. The aim of this studies were to determine the influence of additives on the ceramic phase composition, microstructure and selected properties. Three different kind of mixtures were prepared. 8 to 22 wt% B4C, SiC and Si3N4were added. Composites were sintered under high-pressure high-temperature conditions (HP-HT) using a Bridgman-type apparatus under pressure about 6 GPa. Materials were sintered at the range of 1450 to 1690 ° C, duration of sintering was 60s. The phase composition, microstructure, and the apparent density, Young's modulus, hardness and fracture toughness KIC (HV), using the Vickers indentation method were examined. Sintered titanium nitride with the 22 wt% silicon carbide participation was characterized the best physical and mechanical properties. For this material the relative density is 99%, the Young's modulus 435 GPa, Vickers hardness 18.3 GPa HV1 and fracture toughness 5.5 MPa∙m1/2.

Transparent composites prepared from bacterial cellulose and castor oil based polyurethane as substrates for flexible OLEDs

2015 ◽  
Vol 3 (44) ◽  
pp. 11581-11588 ◽  
Author(s):  
E. R. P. Pinto ◽  
H. S. Barud ◽  
R. R. Silva ◽  
M. Palmieri ◽  
W. L. Polito ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Bacterial Cellulose ◽  
Young’S Modulus ◽  
Castor Oil ◽  
Young's Modulus ◽  
Visible Region ◽  
Transparent Composites

Flexible and transparent BC/PU composites were prepared, which exhibit excellent transparency (up to 90%) in the visible region and great mechanical properties, with a tensile strength of up to 69 MPa and a Young's modulus of up to 6 GPa.

scholarly journals Investigation of the influence of elasticity modulus variation in the ice beam bending model

2020 ◽  
pp. 18-23
Author(s):  
А.А. Симакина
Keyword(s):  
Young’S Modulus ◽  
Numerical Experiments ◽  
Elasticity Modulus ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Random Variable ◽  
Beam Length ◽  
System Parameters ◽  
Beam Bending ◽  
Layered Beam

В работе исследуется влияние неравномерности распределения модуля Юнга в ледяной клавише при ее взаимодействии с наклонным сооружением. Неоднородности в модели отдельно рассматриваются по длине и толщине клавиши. Изменение модуля Юнга по толщине происходит, как правило, в связи с температурным градиентом. При этом лед рассматривается как слоистая балка, в каждом слое которой физико-механические свойства остаются постоянными. При изменении модуля Юнга по длине клавиши рассматривается как простая линейная зависимость, так и представление его как случайной величины. Проведено сравнение результирующих параметров разрушения балки при перечисленных постановках задачи. При помощи статистического моделирования получены кривые, определяющие при различных величинах разброса модуля Юнга границы интервала, в которые значения точек разлома попадают с вероятностью 95% The paper investigates the influence of uneven distribution of Young's modulus in an ice beam during its interaction with an inclined structure. Inhomogeneities in the model considered separately along the length and along the height. The change in Young's modulus along the width occurs in connection with the temperature gradient, when viewed as a layered beam. In each layer of the beam, the physical and mechanical properties of ice remain constant. When Young's modulus is changing along the beam length, its representation is considered as a random variable. The comparison is made of the values of the system parameters with and without taking into account inhomogeneities in the model along the length and width. The study involved a series of numerical experiments to determine the dependence of the standard deviation value of Young's modulus and the interval boundaries in which the values of the breaking point falls with a probability of 95%.

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