scholarly journals Modeling of the roller pressing of fibrous materials

2021 ◽  
Vol 264 ◽  
pp. 01019
Author(s):  
Shavkat Khurramov ◽  
Gayrat Bakhadirov ◽  
Eshmurod Buriev ◽  
Dildora Abduxalikova
Keyword(s):  
Growth Rate ◽  
Pressure Distribution ◽  
Contact Zone ◽  
Fibrous Material ◽  
Initial Point ◽  
Hydraulic Pressure ◽  
Fibrous Materials ◽  
Compression Zone ◽  
Maximum Compression ◽  
Fluid Removal

The work is devoted to modeling the regularities of hydraulic pressure distribution and fluid removal from the fibrous material in the contact zone. It was found that the hydraulic pressure in the compression zone increases from zero at the initial point of contact to a maximum at the point of maximum compression of the fibrous material. The patterns of distribution of hydraulic pressure in the recovery zone depend on the length of the section, where the fluid moves from the layer of material to the elastic coatings. It was revealed that the amount of liquid removed at the beginning of the compression zone grows faster, then the growth rate is much lower, and at the end of the compression zone, the removed liquid is stabilized. The patterns of change in the removed fluid in the recovery zone depend on the angle, which determines the position of the point where the fluid changes direction.

scholarly journals A Theoretical Analysis of Relations between Pressure Changes along Xylem Vessels and Propagation of Variation Potential in Higher Plants

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 372
Author(s):  
Ekaterina Sukhova ◽  
Elena Akinchits ◽  
Sergey V. Gudkov ◽  
Roman Y. Pishchalnikov ◽  
Vladimir Vodeneev ◽  
...  
Keyword(s):  
Higher Plants ◽  
Initial Point ◽  
Electrical Signal ◽  
Terminal Point ◽  
Hydraulic Pressure ◽  
Long Distance ◽  
Variation Potential ◽  
Damaged Zone ◽  
Pressure Dynamics ◽  
The Impact

Variation potential (VP) is an important long-distance electrical signal in higher plants that is induced by local damages, influences numerous physiological processes, and participates in plant adaptation to stressors. The transmission of increased hydraulic pressure through xylem vessels is the probable mechanism of VP propagation in plants; however, the rates of the pressure transmission and VP propagation can strongly vary. We analyzed this problem on the basis of a simple mathematical model of the pressure distribution along a xylem vessel, which was approximated by a tube with a pressure gradient. It is assumed that the VP is initiated if the integral over pressure is more than a threshold one, taking into account that the pressure is transiently increased in the initial point of the tube and is kept constant in the terminal point. It was shown that this simple model can well describe the parameters of VP propagation in higher plants, including the increase in time before VP initiation and the decrease in the rate of VP propagation with an increase in the distance from the zone of damage. Considering three types of the pressure dynamics, our model predicts that the velocity of VP propagation can be stimulated by an increase in the length of a plant shoot and also depends on pressure dynamics in the damaged zone. Our results theoretically support the hypothesis about the impact of pressure variations in xylem vessels on VP propagation.

scholarly journals The 3D structure of fibrous material is fully restorable from its X-ray diffraction pattern

IUCrJ ◽  
2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Hiroyuki Iwamoto
Keyword(s):  
Diffraction Pattern ◽  
Fibrous Material ◽  
3D Structure ◽  
Wide Field ◽  
Fibrous Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fiber Diffraction ◽  
Puzzle Solving ◽  
Diffraction Patterns

X-ray fiber diffraction is potentially a powerful technique to study the structure of fibrous materials, such as DNA and synthetic polymers. However, only rotationally averaged diffraction patterns can be recorded and it is difficult to correctly interpret them without the knowledge of esoteric diffraction theories. Here we demonstrate that, in principle, the non-rotationally averaged 3D structure of a fibrous material can be restored from its fiber diffraction pattern. The method is a simple puzzle-solving process and in ideal cases it does not require any prior knowledge about the structure, such as helical symmetry. We believe that the proposed method has a potential to transform the fiber diffraction to a 3D imaging technique, and will be useful for a wide field of life and materials sciences.

Investigating the Effects of Fibrous Material Compression on the Acoustical Behavior of Absorption and Barrier Materials

2006 ◽  
Vol 129 (2) ◽  
pp. 133-140 ◽  
Author(s):  
A. R. Ohadi ◽  
M. Moghaddami
Keyword(s):  
Absorption Coefficient ◽  
Fibrous Material ◽  
Transmission Loss ◽  
Element Model ◽  
Physical Parameters ◽  
Fibrous Materials ◽  
Barrier Materials ◽  
Rigid Frame ◽  
Absorbing Materials ◽  
The Galerkin Method

This paper discusses the effects of compression on acoustical performance of fibrous materials. A finite element model is used to predict the absorption coefficient and transmission loss of absorbing and barrier materials. This model is developed based on the Galerkin method and includes the equation of wave propagation in rigid frame porous material. The compression of fibrous material is entered to the model with relations that explain modifications of physical properties used in the wave equation. Acoustical behavior of absorption and barrier materials with and without compression is studied. It is shown that compression of the material leads to reduction of the transmission loss of the barrier materials and absorption coefficient of absorbing materials. In this regard, “thickness reduction” and “variations of physical parameters” due to compression are investigated.

An Alternative Method for the Characterisation of Fibrous Materials from Measurements of Absorption Using Techniques Based on the Allard and Champoux Model

2000 ◽  
Vol 31 (8) ◽  
pp. 19-25
Author(s):  
Jesús Alba ◽  
Jaime Ramis
Keyword(s):  
Fibrous Material ◽  
Flow Resistance ◽  
Fibrous Materials ◽  
Specific Flow ◽  
Alternative Method ◽  
Starting Point ◽  
Complete Characterisation ◽  
Absorption Measurements

In this work we present a method for characterising fibrous materials from absorption measurements in the Kundt tube. Specific Flow Resistance may be calculated, using techniques based on the Allard & Champoux model. Using this model and taking measurements of absorption as a starting point, the method presented here enables one to achieve a complete characterisation of a fibrous material.

The Characterization of Fibrous Material in CVI Graphite Cylinder Wall

2017 ◽  
Vol 904 ◽  
pp. 142-145 ◽  
Author(s):  
Min Yang ◽  
Ming Ming Yu ◽  
Hong Li ◽  
Mu Su Ren ◽  
Jia Bao Zhang ◽  
...  
Keyword(s):  
Fibrous Material ◽  
Chemical Vapor Infiltration ◽  
Laser Raman Spectroscopy ◽  
Main Element ◽  
High Temperature Treatment ◽  
Cylinder Wall ◽  
X Rays ◽  
Fibrous Materials ◽  
Graphite Cylinder

By isothermal chemical vapor infiltration (ICVI) preparation of carbon/carbon composites, We found fibrous materials with silver metallic luster in CVI furnace graphite cylinder outer wall, fiber diameter is 1 ~ 2 mm, length is 4 ~ 15 mm. The characterization of fibrous material have been systematically studied by scanning electron microscopy (SEM),element analysis, energy dispersive X-rays spectroscopy (EDS).After 2300 degrees heat treatment, the fibrous material were characterized by ultra-violet laser Raman spectroscopy. The SEM examination shows that these fibrous materials have a spherical top, the cross-section reveals a unique structure in which layers like growth rings lie concentrically on top of each other. The EDS analysis show the main element of fibrous material is carbon and a small amount of metallic element. Raman spectra show after 2300°C high temperature treatment ,the carbon fibrous material transformed from layer structure to graphite structure.

scholarly journals Influence of the processing method on basic physical and mechanical characteristics of the fibrous material

2020 ◽  
Author(s):  
Roman Marchenko ◽  
Valentina Shurkina
Keyword(s):  
Fibrous Material ◽  
Mechanical Characteristics ◽  
Processing Method ◽  
Fibrous Materials ◽  
Processing Methods ◽  
Physical And Mechanical Characteristics

The article presents a brief analysis of various processing methods for fibrous materials

scholarly journals An Investigation of the Radiative Heat Transfer through Nonwoven Fibrous Materials

2009 ◽  
Vol 4 (1) ◽  
pp. 155892500900400 ◽  
Author(s):  
Imad Qashou ◽  
Hooman Vahedi Tafreshi ◽  
Behnam Pourdeyhimi
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Fibrous Material ◽  
Radiative Heat ◽  
Volume Fraction ◽  
Fiber Diameter ◽  
Solid Volume Fraction ◽  
Surface Radiation ◽  
Fibrous Materials ◽  
Heat Penetration

In this study, the surface-to-surface radiation model of the Fluent CFD code is used to investigate the response of a fibrous material to the radiative heat transfer. The unsteady state heat transfer equation is solved for the temperature and heat flux in and around the fibers that constitute a nonwoven fibrous material. For a fixed fiber diameter, it was shown that the higher the fabric's Solid Volume Fraction (SVF), the slower is the material's average temperature rise. Our simulation results also indicate that for a fixed SVF, fiber diameter has a negligible influence on the unsteady transfer of heat through the media. Of particular interest in this paper is the effect of material's thickness on the heat penetration. It is shown that the transient heat transfer exponentially decreases by increasing the material's thickness for fixed SVFs and fiber diameters. The above finding is also in agreement with our experimental study.

Transient Methods of Thermal Properties Measurement on Fibrous Materials

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
Zuo Lei ◽  
Sukang Zhu ◽  
Ning Pan
Keyword(s):  
Fibrous Material ◽  
Local Heat ◽  
Test Methods ◽  
Test Method ◽  
Dual Phase ◽  
Fibrous Materials ◽  
Test Results ◽  
Main Factors ◽  
Transient Methods ◽  
Transfer Properties

Fibrous material is a complex porous medium and steady test methods are the main test approaches we currently depend on to study the heat transfer properties. The application of unsteady test methods on fibrous material is still not mature. In this paper, some systematic studies are taken to investigate this problem. By analyzing the main factors impacting the test results, it is found that the local heat convection potentially excited by imposing test temperature can be avoided by limiting the internal temperature gradient and the so-called dual-phase lagging effects are negligible so that the feasibility of the unsteady test method is verified via both theoretical analysis and experimental data.

Radiative Properties of Dense Fibrous Medium Containing Fibers in the Geometric Limit

2006 ◽  
Vol 128 (10) ◽  
pp. 1022-1030 ◽  
Author(s):  
R. Coquard ◽  
D. Baillis
Keyword(s):  
Monte Carlo ◽  
Extinction Coefficient ◽  
Phase Function ◽  
Fibrous Material ◽  
Radiative Properties ◽  
Circular Cylinders ◽  
Fibrous Materials ◽  
Geometric Optics ◽  
Shadowing Effect ◽  
Radiative Characteristics

The aim of this paper is to investigate the dependent regime in dense fibrous materials with size parameters ranging in the geometric optics limit. We use a method based on a Monte Carlo procedure which permits one to identify the radiative properties of dispersed media. This method is applied to materials made of opaque or semitransparent randomly oriented long circular cylinders representing the fibers. The results permit us to investigate the limit of validity of independent scattering hypothesis and to analyze the evolution of the extinction coefficient, scattering albedo and phase function of the fibrous material with the porosity and the reflecting properties of the particles when the shadowing effect due to geometric sized objects is not negligible. We also propose a correlation to estimate the radiative properties in dependent regime from the results of the independent scattering hypothesis. Thereafter, the radiative characteristics obtained are compared to those predicted by previous authors.

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