Papers by Keyword: Porous Material

Abstract: The micro and nano structures of porous material have strong influence on their transfer properties such as porosity, permeability, tortuosity and adsorption isotherm curves. In the construction and building material field, these properties are strongly related to hydro and thermal comfort, due to the fact that heat and mass transfer mechanisms are determined by the micro porous structure. In the present work, we aim to predict heat and mass transfer on such micro-nano structured materials, with a statistical quantification method that is extracted from morphology aspect. A large range of the pore size (from 20nm to 1mm) is covered and investigated by the multiple approaches, including FIB-SEM, X-Ray Tomography, and MIP (Mercury Intrusion Porosimetry). The 3D view of pore structures is obtained in concrete, as well as their size distribution, and pore zones. A reconstruct of 3D view of pore networks is extracted, with the spatial resolution of 20 nm/pixel. A global view of multiple testing methods and the corresponding size ranges are drawn to summarize the multi-scale approaches, for a potential further understanding of relationship between porous structure and thermal-hydro properties.

Abstract: This research aims to synthesize and characterize Ni(II)-terephthalate-pyrazine complex and to determine the thermal stability and porosity profile of the synthesized compound. The Ni(II)-terephthalate-pyrazine was made by solvothermal reaction using dimethylformamide at 130 and 150 °C and in Ni(II):terephthalic-acid:pyrazine mol ratios of 1:1:2 and 1:1:4. The precipitated products were characterized by infrared spectroscopy, SEM, and powder-XRD in order to confirm the presence of both ligand in the synthesized compound. Meanwhile, the thermal stability and porosity profile of the synthesized compound were determined by DTA-TGA and surface area analysers, respectively. Experimental data shows that green pale powder was obtained from all reactions in considerably good yield, which is different from the dark green crystalline solid of Ni(II)-terephthalate. SEM image reveals that the product has a smooth-wavy surface morphology. Infrared spectra of the synthesized compound show peaks of functional groups of C=O, C–O, C=N, and C–N groups, which confirm the presence of both ligands. Powder XRD analysis suggests that the crystal system of the synthesized compound is different from that of the Ni(II)-terephthalate. Based on these analyses, the targeted Ni(II)-terephthalate-pyrazine is successfully obtained. Moreover, the synthesized compound has lower thermal stability than that of Ni(II)-terephthalate, while the BET calculation suggest that the synthesized compound has pore volume of 0.10-0.14 cm³/g, pore diameter of 8.1-10.65 nm and surface area of 24-30 (m²/g). This porosity profile suggest that the synthesized compound is open for further application, such as adsorption or photocatalysis.

Abstract: This study assesses the motion and the dynamics of heat propagation in magneto-micropolar fluid along a sheet which vertically stretches on a two-dimensional plane in a porous material. The heat distribution is developed and evaluated under the condition of the prescribed wall temperature, constant magnetic field, thermal radiation, variable heat source and viscous dissipation. The main equations are re-formulated from partial to ordinary derivatives using similarity tools and consequently solved numerically by shooting and the Runge-Kutta Fehlberg approach. The parameters of interest are presented graphically to demonstrate their reactions on the velocity profiles, thermal field and heat transfer mechanism of the problem. The outcomes of the current investigation reveal that the heat transfer appreciates in the presence of higher Prandtl number, temperature exponent term and material parameter but decreases as the magnetic field term soars.Besides, the heat boundary structure expands and heat spread occurs as the thermal radiation, magnetic field and Eckert number terms escalates but a reverse trend is encountered as the Prandtl number, material micropolar term, Grashof number and heat exponent terms grows in magnitude. Under some limiting scenarios, the obtained data strongly correspond to the published studies in the open literature.

Abstract: In this study, carboxymethyl peanut shell (CPS) was prepared, and then peanut shell-based porous material (PPS) was obtained by the complexation reaction of CPS with Cu²⁺. The carboxymethyl content of CPS increased gradually with the increase of the amounts of monochloroacetic acid and sodium hydroxide, and the Cu²⁺ loading amount of PPS increased gradually with the increase of carboxymethyl content. The scanning electron microscope results showed that PPS-1, PPS-2, PPS-3 (PPS-1~3) had many nanoscale pores. The nitrogen adsorption-desorption results suggested that PPS-1~3 were all mesoporous materials with an average pore diameter of about 10 nm, while their Brunauer-Emmet-Teller surface area and pore volume of PPS-1 to PPS-3 increased gradually. Compared with the control cigarette, the release of HCN in cigarette mainstream smoke could be effectively reduced with the use of PPS-1~3, the reduction rate of HCN per total particulate matter were 54.9%, 63.1% and 67.0%, respectively.

Abstract: This research was proposed to applying stainless wire mesh porous material for specific energy consumption improvement of a hot air dryer. In experimental consist two main parts, first part was a comparison of drying with and without hot air recirculation duct. Second part was a comparison of drying with and without stainless wire mesh porous material in drying chamber and hot air recirculation duct. Tilapia was drying product, stainless wire mesh in drying chamber was constant PPI=8 and 6 layers, stainless wire mesh in hot air recirculation duct was constant PPI=8 and varied layer at 6, 8 and 12 layers and hot air recirculation ratio 40%, 60% and 80%. Experimental result was, drying with hot air recirculation duct was higher drying rate than without recirculation duct and drying rate was increased, drying time was decreased and SEC was decreased with increased hot air recirculation ratio. At recirculation ratio 80%, SEC was lowest and decreased to 54.52% compared with without recirculation duct. Therefrom, the stainless wire mesh porous materials were inserted in the drying chamber and recirculation duct at PPI=8, 6 layers and PPI=8, 12 layers, respectively and used recirculation ratio 80%, it was found that SEC was lowest and decreased as about 62.21%.

Abstract: Approaches to mathematical modeling of nonlinear strain dynamics in heteromodular and porous materials are discussed; the mechanical properties of media are described in terms of the simple piecewise linear elastic models. Several nonstationary 1D boundary value problems show that the singularity of model relationships gives rise to shock waves and centered Riemann waves in generalized solutions. Nonstationary load modes leading to the listed nonlinear effects are indicated separately for heteromodular and porous media.

Abstract: Copper is a superior antibacterial metal, which is used for various antibacterial products. It is known that the antimicrobial property is generated by direct contact of bacterial cell to the copper surface. Since porous copper has a benefit to increase the surface area contacted to atmospheric medium, it is expected that antibacterial effect can be enhanced. Two kinds of lotus-type porous copper with different directional open pores were used as samples. In order to elucidate such enhancement, four kinds of culture tests on porous copper plates were carried out using bacteria of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella enteritidis. While the counts of viable bacteria of Staphylococcus aureus and Escherichia coli cultured on non-porous copper do not change significantly, the counts of Pseudomonas aeruginosa and Salmonella enteritidis decreases. The counts of the viable bacteria of Staphylococcus aureus and Escherichia coli cultured on porous copper drastically decrease, while the counts of Salmonella enteritidis decreases to some degree. However, the porosity does not affect the decrease of counts of Pseudomonas aeruginosa. Thus, apparent antibacterial property of porous copper is attributed to increase of contact area of the bacteria to porous copper for Staphylococcus aureus, Escherichia coli and Salmonella enteritidis.

Abstract: Gas pores growing inside the columnar grains, instead of at grain boundary regions were observed in a lotus type porous copper. It is suggested that the lack of effective nucleation substrate in the pure copper melt makes the nucleation and subsequent growth of gas pores difficult. Therefore the melt must be sufficiently undercooled to provide enough free energy for the nucleation, and as a result the gas saturated melt will transform into a higher energy state of gas pores inside the columnar grains. Keywords: Porous material; Solidification; Gas Pore; Nucleation.

Abstract: A quantitative ultrasound (QUS) method is developed for estimation of volume fraction of porous Kelvin structure to understand acoustic characteristics of trabecular bone. A Kelvin cellular specimen composed of isotropic tetra-kaidecahedron was produced by 3D printer with ABS plastic material to simulate artificial trabecular bone. The unit cell of Kelvin specimen has a size of 3.4mm and 81% of porosity. The specimen was completely filled with paraffin wax as a substitute of bone marrow. The speed of sound (SOS) of the wax-filled Kelvin specimen was measured using the time-of-flight (TOF) of ultrasound. Based on micro-structural model, shape parameters of Kelvin specimen is correlated with SOS and elastic constant to evaluate volume fraction of the specimen quantitatively. 25.8% of volume fraction was estimated for the Kelvin specimen which has actual volume fraction of 19%. It is concluded from experiment that the ultrasonic method developed in this study is effective and can be applied to diagnose and monitor osteoporosis.

Abstract: Flow insulator is the material which having fluid flow through itself resulting to the fluid temperature difference between the upstream and downstream regions. The flow insulation characteristics of combined two cordierite alumina (Cr-Al) porous plates with 2 mm free space was investigated experimentally. The results indicated the air temperature drop across the flow insulator and the thermal efficiency increase with the inlet air temperature and decrease with increasing air flow rate. The higher PPI porous plate placing upstream layer resulted in increasing the thermal efficiency of the flow insulator significantly.