Ceria-Based Dual-Phase Membranes for High-Temperature Carbon Dioxide Separation: Effect of Iron Doping and Pore Generation with MgO Template

Dual-phase membranes for high-temperature carbon dioxide separation have emerged as promising technology to mitigate anthropogenic greenhouse gases emissions, especially as a pre- and post-combustion separation technique in coal burning power plants. To implement these membranes industrially, the carbon dioxide permeability must be improved. In this study, Ce0.8Sm0.2O2−δ (SDC) and Ce0.8Sm0.19Fe0.01O2−δ (FSDC) ceramic powders were used to form the skeleton in dual-phase membranes. The use of MgO as an environmentally friendly pore generator allows control over the membrane porosity and microstructure in order to compare the effect of the membrane’s ceramic phase. The ceramic powders and the resulting membranes were characterized using ICP-OES, HSM, gravimetric analysis, SEM/EDX, and XRD, and the carbon dioxide flux density was quantified using a high-temperature membrane permeation setup. The carbon dioxide permeability slightly increases with the addition of iron in the FSDC membranes compared to the SDC membranes mainly due to the reported scavenging effect of iron with the siliceous impurities, with an additional potential contribution of an increased crystallite size due to viscous flow sintering. The increased permeability of the FSDC system and the proper microstructure control by MgO can be further extended to optimize carbon dioxide permeability in this membrane system.DFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli

Compact low power infrared tube furnace for in situ X-ray powder diffraction.

We describe the development and implementation of a compact, low power, infrared heated tube furnace for in situ powder X-ray diffraction experiments. Our silicon carbide (SiC) based furnace design exhibits outstanding thermal performance in terms of accuracy control and temperature ramping rates while simultaneously being easy to use, robust to abuse and, due to its small size and low power, producing minimal impact on surrounding equipment. Temperatures in air in excess of 1100 °C can be controlled at an accuracy of better than 1%, with temperature ramping rates up to 100 °C/s. The complete "add-in" device, minus power supply, fits in a cylindrical volume approximately 15 cm long and 6 cm in diameter and resides as close as 1 cm from other sensitive components of our experimental synchrotron endstation without adverse effects

The contrasting effect of the Ta/Nb ratio in (111)-layered B-site deficient hexagonal perovskite Ba5Nb4-xTaxO15 crystals on visible-light-induced photocatalytic water oxidation activity of their oxynitride derivatives

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The effect of the Ta/Nb ratio in the (111)-layered B-site deficient hexagonal perovskite Ba5Nb4-xTaxO15 (0 <= x <= 4) crystals grown by a KCl flux method on visible-light-induced photocatalytic water oxidation activity of their oxynitride derivatives BaNb1-xTaxO2N (0 <= x <= 1) was investigated. The Rietveld refinement of X-ray data revealed that all Ba5Nb4-xTaxO15 samples were well crystallized in the space group P (3) over bar m1 (no. 164). Phase-pure BaNb1-xTaxO2N (0 <= x <= 1) porous structures were obtained by nitridation of the flux-grown oxide crystals at 950 degrees C for 20, 25, 30, 35, and 40 h, respectively. The absorption edge of BaNb1-xTaxO2N (0 <= x <= 1) was slightly shifted from 720 to 690 nm with the increasing Ta/Nb ratio. The O-2 evolution rate gradually progressed and reached the highest value (127.24 mu mol in the first 2 h) with the Ta content up to 50 mol% but decreased at 75 and 100 mol% presumably due to the reduced specific surface area and high density of structural defects, such as grain boundaries acting as recombination centers, originated from high-temperature nitridation for prolonged periods. Transient absorption spectroscopy provided evidence for the effect of the Ta/Nb ratio on the behavior and energy states of photogenerated charge carriers, indicating a direct correlation with photocatalytic water oxidation activity of BaNb1-xTaxO2N

In vitro cultures of Silybum marianum and silymarin accumulation

AbstractIn this study, a protocol for initiation of callus and shoot cultures from leaves and shoot tips explants of different silybium genotypes collected from different locations in Egypt was established. Callus cultures were initiated from leaves explants and exposed to different concentrations of the precursor (coniferyl alcohol). Shoot cultures were initiated from shoot tips explants. Moreover, the produced plants of the different Silybium shoots as well as intact plants were subjected to protein screening using SDS–PAGE analysis.Results obtained revealed that the optimum medium for growth and maintenance of friable callus was MS medium supplemented with 0.25mgL−1 2,4-Dichlorophenoxy acetic acid (2,4-D)+0.25mg L−1 Kinetin (Kin). The best medium for proliferation of high number of shoots was MS-medium with 0.25mgL−1 each of Benzyl Adinine (BA) and Naphthalene Acetic Acid (NAA). Coniferyl alcohol in concentration of 30μM caused an increase in accumulation of silymarin contents in most callus cultures. SDS–PAGE of different Silybium shoots revealed that the protein profiles of 100% of in vitro produced plantlets similar to their control

Surface chemistry and stability of metastable corundum-type In2O3

To account for the explanation of an eventual sensing and catalytic behavior of rhombohedral In2O3 (rh-In2O3) and the dependence of the metastability of the latter on gas atmospheres, in situ electrochemical impedance spectroscopic (EIS), Fourier-transform infrared spectroscopic (FT-IR), in situ X-ray diffraction and in situ thermogravimetric analyses in inert (helium) and reactive gases (hydrogen, carbon monoxide and carbon dioxide) have been conducted to link the gas-dependent electrical conductivity features and the surface chemical properties to its metastability towards cubic In2O3. In particular, for highly reducible oxides such as In2O3, for which not only the formation of oxygen vacancies, but deep reduction to the metallic state (i.e. metallic indium) also has to be taken into account, this approach is imperative. Temperature-dependent impedance features are strongly dependent on the respective gas composition and are assigned to distinct changes in either surface adsorbates or free charge carrier absorbance, allowing for differentiating and distinguishing between bulk reduction-related features from those directly arising from surface chemical alterations. For the measurements in an inert gas atmosphere, this analysis specifically also included monitoring the fate of differently bonded, and hence, differently reactive, hydroxyl groups. Reduction of rh-In2O3 proceeds to a large extent indirectly via rh-In2O3 → c-In2O3 → In metal. As deduced from the CO and CO2 adsorption experiments, rhombohedral In2O3 exhibits predominantly Lewis acidic surface sites. The basic character is less pronounced, directly explaining the previously observed high (inverse) water–gas shift activity and the low CO2 selectivity in methanol steam reforming.DFG, SPP 1415, Kristalline Nichtgleichgewichtsphasen - Präparation, Charakterisierung und in situ-Untersuchung der Bildungsmechanisme

On-chip assembly of 3D graphene-based aerogels for chemiresistive gas sensing

Integration of the material preparation step into the device fabrication process is of prime importance for the development of high performance devices. This study presents an innovative strategy for the in situ assembly of graphene-based aerogels on a chip by polymerization–reduction and annealing processes, which are applied as chemiresistive gas sensors for the detection of NO2.TU Berlin, Open-Access-Mittel - 201

Chronically-implanted Neuropixels probes enable high yield recordings in freely moving mice

The advent of high-yield electrophysiology using Neuropixels probes is now enabling researchers to simultaneously record hundreds of neurons with remarkably high signal to noise. However, these probes have not been well-suited to use in freely moving mice. It is critical to study neural activity in unrestricted animals for many reasons, such as leveraging ethological approaches to study neural circuits. We designed and implemented a novel device that allows Neuropixels probes to be customized for chronically-implanted experiments in freely moving mice. We demonstrate the ease and utility of this approach in recording hundreds of neurons during an ethological behavior across weeks of experiments. We provide the technical drawings and procedures for other researchers to do the same. Importantly, our approach enables researchers to explant and reuse these valuable probes, a transformative step which has not been established for recordings with any type of chronically-implanted probe

Chronically-implanted Neuropixels probes enable high yield recordings in freely moving mice: dataset

The advent of high-yield electrophysiology using Neuropixels probes is now enabling researchers to simultaneously record hundreds of neurons with remarkably high signal to noise. However, these probes have not been well-suited to use in freely moving mice. It is critical to study neural activity in unrestricted animals for many reasons, such as leveraging ethological approaches to study neural circuits. We designed and implemented a novel device that allows Neuropixels probes to be customized for chronically-implanted experiments in freely moving mice. We demonstrate the ease and utility of this approach in recording hundreds of neurons during an ethological behavior across weeks of experiments. We provide the technical drawings and procedures for other researchers to do the same. Importantly, our approach enables researchers to explant and reuse these valuable probes, a transformative step which has not been established for recordings with any type of chronically-implanted probe

Involute Gear Tooth Stresses Analysis Using Finite Element Modeling

The bending and surface stresses of gear tooth are major factor for failure of gear. Pitting is a surface fatigue failure due to repetitions of high contact stresses. This paper presented analysis of bending and contact stresses of involute teeth of spur gear in meshing. The involute profile of spur gear has been modeled and the simulation is carried out for analysis of stresses and deformation. 2D and 3D models are simulated. The tooth involute is designed from which the tooth is extruded to form the 3D models of spur gear. The simulation is done by finite element software package ANSYS Workbench 16.2. These stresses are also estimated using AGMA bending and contact stresses equations for comparison. The results show that the 2D model is more accurate than the 3D.   Care must be taken when selecting the type of contact condition since the results are very sensitive to it.  Also it is found that the elastic modulus of the material is greatly affecting the contact stresses. Poor accuracy is achieved for the bending stresses while the contact stress shows very accurate results.

Iraqi Economy and Renewable Energy Projects Between Economic Necessity and Investment Challenges

Purpose: Given Iraq's current excessive fossil fuel output, this article seeks to investigate the country's potential for future renewable energy sources. The report also endeavors to foresee Iraq's future position in clean energy production in Iraq and throughout the globe and the rate at which the global energy market will shift towards renewable energy sources. &nbsp; Theoretical framework: Iraq's reliance on oil earnings and the country's overburdened public sector poses serious economic issues. There is a domination of state-owned firms, stringent laws, a need for more access to finance, a shortage of competent labor, and poor infrastructure that limits the expansion of numerous industries. Growth in recent years has not led to decreased poverty since the economy has changed greatly since 2014. &nbsp; Design/Methodology/Approach: The study included both retrospective and prospective approaches. The most pressing problems in implementing and making use of renewable energy sources were described and analyzed descriptively. Future outcomes for the Iraqi economy were envisioned using a prospective approach in the form of development scenarios. &nbsp; Findings: A significant source of international capital flows and a key source of funding for economic growth, foreign direct investment (FDI) has mostly focused on the oil industry and certain tourism projects. As a result of the country's outdated energy grid, investors are interested in something other than investing in Iraq's electrical industry. &nbsp; Research, practical &amp; social implications: We describe the current issues confronting Iraqi economic development, including the need for more diversity in the economy, structural imbalances between the main sectors, and the near-total dependence on crude oil export revenues, resulting in a decline in industrial production. &nbsp; Originality/Value: We describe the reality of the Iraqi economy, analyze the structure of Iraq's energy sector based on conventional energy, and then find out about the progress made in renewable energy and existing and future projects under fossil fuels