scholarly journals The Elucidation of the Molecular Mechanism of the Extrusion Process

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4278
Author(s):  
Joanna Doskocz ◽  
Paulina Dałek ◽  
Magdalena Przybyło ◽  
Barbara Trzebicka ◽  
Aleksander Foryś ◽  
...  

Extrusion is a popular method for producing homogenous population of unilamellar liposomes. The technique relies on forcing a lipid suspension through cylindrical pores in a polycarbonate membrane. The quantification of the extrusion and/or recalibration processes make possible the acquisition of experimental data, which can be correlated with the mechanical properties of the lipid bilayer. In this work, the force needed for the extrusion process was correlated with the mechanical properties of a lipid bilayer derived from other experiments. Measurements were performed using a home-made dedicated device capable of maintaining a stable volumetric flux of a liposome suspension through well-defined pores and to continuously measure the extrusion force. Based on the obtained results, the correlation between the lipid bilayer bending rigidity and extrusion force was derived. Specifically, it was found that the bending rigidity of liposomes formed from well-defined lipid mixtures agrees with data obtained by others using flicker-noise spectroscopy or micromanipulation. The other issue addressed in the presented studies was the identification of molecular mechanisms leading to the formation of unilamellar vesicles in the extrusion process. Finally, it was demonstrated that during the extrusion, lipids are not exchanged between vesicles, i.e., vesicles can divide but no membrane fusion or lipid exchange between bilayers was detected.

2018 ◽  
Vol 251 (4) ◽  
pp. 601-608
Author(s):  
Joanna Doskocz ◽  
Dominik Drabik ◽  
Grzegorz Chodaczek ◽  
Magdalena Przybyło ◽  
Marek Langner

Author(s):  
Branimir Lela ◽  
Jure Krolo

This article deals with the direct recycling of EN AW 2011 aluminum alloy chips, which are formed by turning, into semifinished products using forward hot extrusion process. Direct recycling without re-melting is usually called solid-state recycling. The main aim of this article is to investigate the influence of depth of cut (size of chips) in the aluminum alloy turning process, extrusion temperature, and compaction force on mechanical properties, surface roughness, and extrusion force of recycled samples. An original approach to solve this problem is mathematical modelling of the process using the design of experiments. The influence of main research factors on yield strength (Rp0,2), hardness (HV), extrusion force (F), and surface roughness (Ra) of recycled samples has been studied. The study has shown that the most influential factor on mechanical properties, surface roughness, and extrusion force was extrusion temperature.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3560
Author(s):  
Tomasz Skrzekut ◽  
Grzegorz Boczkal ◽  
Adam Zwoliński ◽  
Piotr Noga ◽  
Lucyna Jaworska ◽  
...  

Zr-2.5Cu and Zr-10Cu powder mixtures were consolidated in the extrusion process and using the spark plasma sintering technique. In these studies, material tests were carried out in the fields of phase composition, microstructure, hardness and tensile strength for Zr-Cu materials at room temperature (RT) and 400 °C. Fractography analysis of materials at room temperature and 400 °C was carried out. The research took into account the anisotropy of the materials obtained in the extrusion process. For the nonequilibrium SPS process, ZrCu2 and Cu10Zr7 intermetallic compounds formed in the material at sintering temperature. Extruded materials were composed mainly of α-Zr and ZrCu2. The presence of intermetallic compounds affected the reduction in the strength properties of the tested materials. The highest strength value of 205 MPa was obtained for the extruded Zr-2.5Cu, for which the samples were cut in the direction of extrusion. For materials with 10 wt.% copper, more participation of the intermetallic phase was formed, which lowered the mechanical properties of the obtained materials. In addition to brittle intermetallic phases, the materials were characterized by residual porosity, which also reduced the strength properties.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2989
Author(s):  
Halina Szafranska ◽  
Ryszard Korycki

In order to ensure a comprehensive evaluation of laminated seams in working clothing, a series of research was carried out to determine the correlation between the parameters of the seam lamination process (i.e., the temperature, the time, the pressure) and the mechanical properties of laminated seams. The mechanical properties were defined by means of the maximum breaking force, the relative elongation at break and the total bending rigidity. The mechanical indexes were accepted as the measure of durability and stability of laminated seams. The correlation between the lamination process parameters and the final properties of the tested seams in working clothing was proposed using a three-factor plan 33. Finally, the single-criteria optimization was introduced and the objective functional is the generalized utility function U. Instead of three independent optimization problems, the single problem was applied, and the global objective function was a weighted average of partial criteria with the assumed weight values. The problem of multicriteria weighted optimization was solved using the determined weights and the ranges of acceptable/unacceptable values.


2020 ◽  
Vol 62 (4) ◽  
pp. 395-399
Author(s):  
Jiehui Liu ◽  
Hongjun Hu ◽  
Yang Liu ◽  
Dingfei Zhang ◽  
Zhongwen Ou ◽  
...  

Abstract Compound extrusion (CE) is a newly developed plastic deformation technique which combines direct extrusion (DE) with a two-pass equal channel angular extrusion (ECAE). This paper focuses on the strength, ductility and anti-corrosion properties of an NaCl solution at certain concentrations and the wear-resistance of dry sliding AZ61 magnesium alloy prepared by CE and DE. It is found that the strength and elongation of the AZ61 alloy prepared by CE are enhanced because of grain refinement. Furthermore, AZ61 magnesium alloy made by CE displays higher corrosion and wear resistance than that prepared by DE. Experimental results prove that CE is a prospective manufacturing method for improving the mechanical properties, anti-corrosion and anti-wear of AZ61 magnesium alloy.


2021 ◽  
Vol 36 (2) ◽  
pp. 219-227
Author(s):  
P. Saiprasit ◽  
A. K. Schlarb

Abstract Poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT)-based nanocomposites filled with 1 vol.% silicon dioxide nanoparticles (nano-SiO2) were prepared using a co-rotating twin-screw extruder and injection molding. The nanocomposites with various blending sequences were investigated using PLA-based and PBAT-based nanocomposite masterbatches. Morphology of the PLA/PBAT/SiO2 nanocomposites was examined using a scanning electron microscope (SEM) and a focused ion beam (FIB) SEM. It is found that the nano-SiO2 locates in the original polymer phase, in which it is firstly incorporated in the masterbatch process, as well as at the interface between the two polymers. However, as the residence time in the extrusion process increases, the nanoparticles migrate from the original phase to the interface, governed by the thermodynamic driving force. The best optimization of mechanical properties is achieved by using the PBAT-based masterbatches with a one-step process or short residence time. The processing history, therefore, has a tremendous impact on the final properties of the resulting materials.


2011 ◽  
Vol 11 (2) ◽  
pp. 541-548 ◽  
Author(s):  
G. V. Ryabinin ◽  
Yu. S. Polyakov ◽  
V. A. Gavrilov ◽  
S. F. Timashev

Abstract. A phenomenological systems approach for identifying potential precursors in multiple signals of different types for the same local seismically active region is proposed based on the assumption that a large earthquake may be preceded by a system reconfiguration (preparation) on different time and space scales. A nonstationarity factor introduced within the framework of flicker-noise spectroscopy, a statistical physics approach to the analysis of time series, is used as the dimensionless criterion for detecting qualitative (precursory) changes within relatively short time intervals in arbitrary signals. Nonstationarity factors for chlorine-ion concentration variations in the underground water of two boreholes on the Kamchatka peninsula and geacoustic emissions in a deep borehole within the same seismic zone are studied together in the time frame around a large earthquake on 8 October 2001. It is shown that nonstationarity factor spikes (potential precursors) take place in the interval from 70 to 50 days before the earthquake for the hydrogeochemical data and at 29 and 6 days in advance for the geoacoustic data.


2021 ◽  
Vol 6 (2) ◽  
pp. 119
Author(s):  
Nanang Ali Sutisna ◽  
Rakha Amrillah Fattah

The method of producing items through synchronously depositing material level by level, based on 3D digital models, is named Additive Manufacturing (AM) or 3D-printing. Amongs many AM methods, the Fused Deposition Modeling (FDM) technique along with PLA (Polylactic acid) material is commonly used in additive manufacturing. Until now, the mechanical properties of the AM components could not be calculated or estimated until they've been assembled and checked. In this work, a novel approach is suggested as to how the extrusion process affects the mechanical properties of the printed component to obtain how the parts can be manufactured or printed to achieve improved mechanical properties. This methodology is based on an experimental procedure in which the combination of parameters to achieve an optimal from a manufacturing experiment and its value can be determined, the results obtained show the effect of the extrusion process affects the mechanical properties.


2009 ◽  
Vol 16-19 ◽  
pp. 515-519
Author(s):  
Hua Xiang ◽  
Xin Cun Zhuang ◽  
Zhen Zhao

Extrusion force plays a significant role on sheet metal extrusion process. It is characterized by various process parameters including material properties, extrusion ratio, friction, tool shape etc. In this paper, a reasonable FEM model of sheet metal extrusion process was established and validated by comparing the results of simulation and experiment firstly. Based on the reliable model, the effect on extrusion force of various process parameters was investigated with orthogonal experimental design combined FEM simulation. The work presented in this paper has laid certain foundation for further work of modeling and optimizing extrusion force.


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