Influence of Hipping Pressure on the Strength and the Porosity of Porous Copper

1991 ◽  
Vol 251 ◽  
Author(s):  
Atsushi Takata ◽  
K. Ishizaki ◽  
Y. Kondo ◽  
T. Shioura
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Young’S Modulus ◽  
Open Porosity ◽  
Structural Parameters ◽  
High Strength ◽  
Porous Copper ◽  
Different Temperatures ◽  
Hip Process

ABSTRACTOpen porous copper metals, which have high strength, high open porosity and well controlled pore size distribution, were produced by a hot isostatic press (HIP) process. They were sintered at different temperatures from 973 to 1273K under various HIPping pressures up to 200MPa. Pore size distribution and Young's modulus of the sintered samples were analyzed. The HIPped products have greater strength and higher open porosity than those of the normally sintered ones. The internal structural parameters such as pore size distribution were controlled by changing the HIPping pressure.

Effect of Drying on Porous Characteristics of Orange Peel

2016 ◽  
Vol 12 (9) ◽  
pp. 921-928 ◽  
Author(s):  
Cansu Tamer ◽  
Asli Isci ◽  
Naciye Kutlu ◽  
Ozge Sakiyan ◽  
Serpil Sahin ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Orange Peel ◽  
Sem Analysis ◽  
Shrinkage Porosity ◽  
Process Conditions ◽  
Third Order ◽  
Strong Negative Correlation ◽  
Different Temperatures

Abstract The purpose of the study was to determine the effects of different temperatures (40, 50 and 60 °C) and air velocities (1 and 2 m/s) on shrinkage, porosity, pore size distribution, color and microstructure of orange peel. Empirical models were also proposed to predict shrinkage and porosity as a function of moisture. A strong negative correlation was determined between moisture and shrinkage. Air temperature had no significant impact on the final shrinkage and porosity values. During drying, porosity of the samples first increased until a critical value, at which point further decrease in moisture resulted in collapse of pores. The porosity of the orange peel was correlated with moisture by a third-order polynomial. Pore size distribution curve of raw sample showed two major peaks, a wider and a sharper peak at around 19.8 and 7.18 μm, respectively. After drying, the peaks became shorter and the curve shifted to the left, indicating that the amount of pores and their diameter decreased. The SEM analysis revealed that at extreme process conditions, the orange peel surface was cracked and the characteristic distribution of the waxy components was obstructed.

Moisture Buffering Potential of Plasters for Energy Efficiency in Modern Buildings

2017 ◽  
Author(s):  
Jan Fořt ◽  
Magdaléna Doleželová ◽  
Robert Černý
Keyword(s):  
Relative Humidity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Open Porosity ◽  
Building Materials ◽  
High Energy ◽  
Building Envelopes ◽  
Moisture Buffering ◽  
Ventilation Systems

Moisture level significantly affects durability of constructions, their thermal performance and quality of indoor air. Since building envelopes are subjected to a moisture gradient, additional ventilation systems are employed to maintain relative humidity on the desired level. Although modern advanced ventilation systems provide sufficient air exchange rate, their wider application is in conflict with sustainability development principles due to high energy demands. Moreover, according to the European legislation related to the Nearly Zero Energy Buildings (European Directives 2002/91/EC and 2010/31/EU), air tightness of building envelopes in order to provide high thermal resistance leads to large moisture loads in building interiors. Among other factors, a high level of relative humidity has negative effect on the work efficiency and health of building inhabitants. A detailed insight into building materials behavior during cyclic moisture loading was accessed within this study. The moisture buffering values of three interior plasters were investigated in order to describe influence of plasters on moderation of indoor environment. Particular materials were loaded according to the NORDTEST protocol by 8/16 h loading schema at 70/30% RH. Here, the excellent moisture buffer classification was obtained for lightweight perlite plaster (PT) with the highest total open porosity. However, contrary to the higher total open porosity of renovation plaster (PS), the core plaster (CP) achieved higher moisture buffer capacity than PS. This discrepancy refers to the influence of the pore size distribution which is, besides the total open porosity, essential for a detailed characterization of moisture buffering potential of building materials. Based on the results of Mercury intrusion porosimetry, a correlation between pore size distribution and moisture buffer value was revealed.

Properties and Structure of Micro Porous Mullite-Corundum Refractory with High Strength

2010 ◽  
Vol 105-106 ◽  
pp. 23-26
Author(s):  
Juan Wu ◽  
Dao Yuan Yang ◽  
Kai Zhu ◽  
Rui Zhang
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Raw Materials ◽  
High Strength ◽  
Casting Process ◽  
Solid Content ◽  
Apparent Porosity ◽  
Corundum Refractory ◽  
Low Viscosity

Mullite- corundum ceramic was fabricated using bauxite and silica fume as raw materials by gel-casting process. The fluidity of the slurry, as well as strength, apparent porosity, pore size distribution, phase composition and microstructure of sintered specimen were studied. The results showed that: the slurry had low viscosity, good fluidity for casting if pH=9, dispersant 0.33wt% and solid content 60vol%; the strength of material came up to 165MPa even if the apparent porosity was about 30%; the samples were characterized by mullite 70%, corundum 22%, rutile 3%, glass phase only 5%, the size of majority grains was about 2μm, and most crystals with high melting point bonded directly; the average aperture was 264nm, the pore size distribution were divided into 2~30nm, 45~60nm and 1500~4000nm three regions. The distribution probability of nano- aperture was the largest, the volume of micron -aperture was the maximum, but all pores were less than 4μm in diameter, which suggested that the materials had micro porous characteristics. The microcrystalline, crystals combined directly and micro porous structure leaded to high strength of the refractory materials together.

scholarly journals Influence of Pore Size Variation on Thermal Conductivity of Open-Porous Foams

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2017 ◽  
Author(s):  
Jakub Skibinski ◽  
Karol Cwieka ◽  
Samih Haj Ibrahim ◽  
Tomasz Wejrzanowski
Keyword(s):  
Thermal Conductivity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Structural Parameters ◽  
Size Variation ◽  
Design Procedure ◽  
Open Cell ◽  
Open Cell Foam ◽  
Analytical Formulas

This study addresses the influence of pore size variation on the effective thermal conductivity of open-cell foam structures. Numerical design procedure which renders it possible to control chosen structural parameters has been developed based on characterization of commercially available open-cell copper foams. Open-porous materials with various pore size distribution were numerically designed using the Laguerre–Voronoi Tessellations procedure. Heat transfer through an isolated structure was simulated with the finite element method. The results reveal that thermal conductivity is strongly related to porosity, which is in agreement with the literature. The influence of pore size distribution has also been observed and compared with analytical formulas proposed in the literature.

Preparation and Characterization of Composite Membrane Chitosan-Silica-Polyethylene Glycol

2018 ◽  
Vol 382 ◽  
pp. 3-6
Author(s):  
F. Widhi Mahatmanti ◽  
Nuryono ◽  
Dwi Siswanta
Keyword(s):  
Polyethylene Glycol ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Young’S Modulus ◽  
Functional Groups ◽  
Composite Membrane ◽  
Young's Modulus ◽  
Percent Elongation ◽  
Physical And Chemical

Chitosan membrane (Ch) has mechanical stability, physical, and chemical low thus limiting their application to a variety of purposes. Therefore in this study examined the effect of adding silica and polyethylene glycol (PEG) on the mechanical properties, physical, and chemical chitosan-based membranes. A source of silica used is tetraethyl orthosilicate (TEOS). Composite membrane Chitosan-silica-PEG (Ch/Si/P) was prepared using the sol-gel process and characterized morphology, crystallinity, and changes in functional groups. In general, the addition of silica in the preparation of composite membrane Ch/Si, increases tensile strength, Young's Modulus, pore size distribution, as well as lower percent Elongation but does not affect the crystallinity and the change of functional groups on the membrane. The addition of PEG on manufacture composite membrane Ch/Si/P, increases the percent Elongation, Young's Modulus decrease and decreased pore size distribution, but does not affect the crystallinity, as well as to changes in the functional groups on the membrane. The results showed that membrane with a mass ratio of chitosan/silica/PEG of 1:0.7:0.5 have a maximum percent Elongation and the minimum Young's Modulus.

scholarly journals Open Porosity and Pore Size Distribution of Mesoporous Silica Films Investigated by Positron Annihilation Lifetime Spectroscopy and Ellipsometric Porosimetry

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3371
Author(s):  
Bangyun Xiong ◽  
Jingjing Li ◽  
Chunqing He ◽  
Jiale Lai ◽  
Xiangjia Liu ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Positron Annihilation ◽  
Open Porosity ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Silica Films ◽  
Ellipsometric Porosimetry ◽  
Positron Annihilation Lifetime

Tunable mesoporous silica films were prepared though a sol-gel process directed by the self-assembly of various triblock copolymers. Positron annihilation γ-ray energy spectroscopy and positron annihilation lifetime spectroscopy (PALS) based on intense pulsed slow positron beams as well as ellipsometric porosimetry (EP) combined with heptane adsorption were utilized to characterize the open porosity/interconnectivity and pore size distribution for the prepared films. The consistency between the open porosities was examined by the variations of orthopositronium (o-Ps) 3γ annihilation fractions and the total adsorbed volumes of heptane. The average pore sizes deduced by PALS from the longest-lived o-Ps lifetimes are in good agreement with those by EP on the basis of the Barrett–Joyner–Halenda model, as indicated by a well fitted line of slope k = 1. The results indicate that the EP combined with heptane adsorption is a useful method with high sensitivity for calibrating the mesopore size in highly interconnected mesoporous films, whereas PALS is a novel, complementary tool for characterizing both closed and open pores in them.

pyGAPS: A Python-Based Framework for Adsorption Isotherm Processing and Material Characterisation

2019 ◽  
Author(s):  
Paul Iacomi ◽  
Philip L. Llewellyn
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Isosteric Heat ◽  
Material Characterisation ◽  
Mixture Adsorption ◽  
Surface Energetics ◽  
Adsorption Processing ◽  
User Friendly

Material characterisation through adsorption is a widely-used laboratory technique. The isotherms obtained through volumetric or gravimetric experiments impart insight through their features but can also be analysed to determine material characteristics such as specific surface area, pore size distribution, surface energetics, or used for predicting mixture adsorption. The pyGAPS (python General Adsorption Processing Suite) framework was developed to address the need for high-throughput processing of such adsorption data, independent of the origin, while also being capable of presenting individual results in a user-friendly manner. It contains many common characterisation methods such as: BET and Langmuir surface area, t and α plots, pore size distribution calculations (BJH, Dollimore-Heal, Horvath-Kawazoe, DFT/NLDFT kernel fitting), isosteric heat calculations, IAST calculations, isotherm modelling and more, as well as the ability to import and store data from Excel, CSV, JSON and sqlite databases. In this work, a description of the capabilities of pyGAPS is presented. The code is then be used in two case studies: a routine characterisation of a UiO-66(Zr) sample and in the processing of an adsorption dataset of a commercial carbon (Takeda 5A) for applications in gas separation.

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