Growth and Coalescence of γ’-Precipitates in Nickel-Based Alloy 115NC during Slow Cooling for Membrane Manufacturing

By coarsening of the γ’-precipitates and selective extraction of one of the two existing phases, porous structures can be produced from nickel-based superalloys. There are two basic approaches to achieve a bicontinuous γ/γ’-microstructure—directional and incoherent coarsening. Single crystalline superalloy membranes are produced by the so-called rafting of the microstructure, i.e., directional coarsening. Unlike this process, incoherently coarsened membranes lack a detailed understanding of the mechanisms leading to cross-linking of the precipitates. In this paper, the growth and coalescence of precipitates during initial slow cooling from above the γ’ solvus temperature was studied. In addition to the three-dimensional morphological changes of the precipitates, it is also shown that only little coalescence of the particles occurs despite the high γ’ content and, therefore, their very small distance. The loss of coherency that occurs during this part of coarsening must first advance through further aging before a bicontinuous microstructure is formed.

The functionalization of pyrolyzed palm empty fruit bunches-based membranes adsorbent by fourier-transform infrared spectroscopy

Membranes adsorbent are successfully prepared derived from palm empty fruit bunches (PEFB) which pyrolyzed by furnace as physical activation. The PEFB membrane adsorbent was activated to develop porous structures and surface area which able to be applied for gas separation. The aims of this study are to fabricated the pyrolyzed PEFB-based membrane adsorbent with different loading of PEFB mass to identify the surface organic functional groups of the PEFB membrane adsorbent. Fabrication of this membrane adsorbent was conducted into three steps, i.e. (1) pre-treated PEFB materials; (2) pyrolyzed the PEFB adsorbent at 500°C; and (3) PEFB membrane adsorbent fabrication by mixed both of PVA and PEG polymers into PEFB adsorbent with varied mass (15-17.5 grams). The functionalization of this membrane adsorbents was analysed by Fourier Transform Infra-Red (FTIR) spectra. The result shows the three variations of the PEFB membrane adsorbents present the surface oxygen, functional group. The effect of PEFB mass loading to the carbon pores formation of PEFB membrane adsorbent was exhibited by the escalating of C-H and C-O groups. The membrane adsorbent by adding 17.5 grams of PEFB mass indicating the highest peak of hydroxyl C-O at wavenumber 1070 cm−1. It demonstrates that membrane adsorbent with high PEFB mass loading and physic activation by pyrolyzing is great to tailoring the membrane adsorbent structure properties which capable to be applied for gas separation, especially for biogas upgrading.

Engineering of protein crystals for use as solid biomaterials

Protein crystals have attracted a great deal of attention as solid biomaterials because they have porous structures created by regular assemblies of proteins. The lattice structures of protein crystals are...

Heat transfer for the boiling crisis in porous systems

In this paper we analized and investigated the heat exchange crisis of boiling in porous structures, applicable in thermal power plants. Then we describe the heat exchange processes mechanism and determined the ideal sizes and thicknesses of porous structures. The designed porous structures can be implemented in gas turbine’s nozzles and combustion chambers. From an environmental point of view, the consumption coolant liquid is reduced by ten times in comparison the standard flow system. It’s effectively to develop mesh structures to allow the extension of the critical loads and manage the surface border.

Study heat exchange in porous structures

This paper shows the problem with heat exchange depending on units of thermal power plant equipment. The type of structures is determined and the heat flow for different pressures is proposed. Studies are developed for the condition of the heat exchange surface. Devices with porous coatings eliminate the development of cracks in the components and units of TPP equipment have been suggested. The research is applicable to gas turbine units of TPP. Comparable capillary-porous and flow systems have high reliability, but the former allowed the reduction of coolant consumption dozens up to 80 times. The results show that at higher heat loads it is suitable to use in porous surfaces to control the cooling surface. Evaluation of capillary-porous structures has shown their advantages over traditional cooling systems.

A large-area flexible tactile sensor for multi-touch and force detection using electrical impedance tomography

In this paper, a large-area flexible tactile sensor for multi-touch and force detection based on EIT technology was developed. A novel design of a sensor material made of a porous elastic polymer and ionic liquid was proposed. The proposed conductive flexible materials combining elastic porous structures and conductive liquids provide continuous, linear changes in impedance with respect to touch forces. A deep learning scheme PSPNet based on MobileNet was adopted to postprocess the originally reconstructed images to improve the performance of tactile perception. By using this data-driven method, we can improve the spatial resolution of the tactile sensor to achieve a single-point position detection error of 7.5±4.5 mm without using internal electrodes.

Application of Porous Materials for CO2 Reutilization: A Review

CO2 reutilization processes contribute to the mitigation of CO2 as a potent greenhouse gas (GHG) through reusing and converting it into economically valuable chemical products including methanol, dimethyl ether, and methane. Solar thermochemical conversion and photochemical and electrochemical CO2 reduction processes are emerging technologies in which solar energy is utilized to provide the energy required for the endothermic dissociation of CO2. Owing to the surface-dependent nature of these technologies, their performance is significantly reliant on the solid reactant/catalyst accessible surface area. Solid porous structures either entirely made from the catalyst or used as a support for coating the catalyst/solid reactants can increase the number of active reaction sites and, thus, the kinetics of CO2 reutilization reactions. This paper reviews the principles and application of porous materials for CO2 reutilization pathways in solar thermochemical, photochemical, and electrochemical reduction technologies. Then, the state of the development of each technology is critically reviewed and evaluated with the focus on the use of porous materials. Finally, the research needs and challenges are presented to further advance the implementation of porous materials in the CO2 reutilization processes and the commercialization of the aforementioned technologies.