Biofixation of carbon dioxide by Chlorococcum sp. in a photobioreactor with polytetrafluoroethene membrane sparger

The greenhouse effect, caused by excessive carbon dioxide emissions, constitutes a major aspect of global warming. Biological fixation of carbon dioxide using microalgae is an effective carbon dioxide reduction technology, but its widespread implementation is limited by the poor mass transfer efficiency. In this study, Chlorococcum sp. was cultured in a photobioreactor with a polytetrafluoroethene membrane sparger (PTFE) to study CO2 biofixation and microalgae growth. Daily variations of dissolved oxygen (DO), pH and dissolved CO2 were analyzed during batch culture of Chlorococcum sp. in the photobioreactor. The culture of Chlorococcum sp. under different operating conditions, such as pH, light cycle (light:dark) and nitrate feeding, were carried out to optimize the CO2 biofixation rate and the algal productivity. The results confirmed that the photobioreactor with a membrane sparger is an alternative option for CO2 removal from flue gas by cultivation of microalgae.Keywords: Bioreactor, polytetrafluoroethene membrane sparger (PTFE) membrane sparger, Chlorococcum sp., greenhouse gasAfrican Journal of Biotechnology Vol. 11(29), pp. 7445-7453, 10 April, 201

Gas-Liquid Stratified Flow in Pipeline with Phase Change

When the natural gas with vapor is flowing in production pipeline, condensation occurs and leads to serious problems such as condensed liquid accumulation, pressure and flow rate fluctuations, and pipeline blockage. This chapter aims at studying phase change of vapor and liquid-level change during the condensing process of water-bearing natural gas characterized by coupled hydrothermal transition and phase change process. A hydrothermal mass transfer coupling model is established. The bipolar coordinate system is utilized to obtain a rectangular calculation domain. An adaptive meshing method is developed to automatically refine the grid near the gas-liquid interface. During phase change process, the temperature drop along the pipe leads to the reduction of gas mass flow rate and the rise of liquid level, which results in further pressure drop. Latent heat is released during the vapor condensing process which slows down the temperature drop. Larger temperature drop results in bigger liquid holdup while larger pressure drop causes smaller liquid holdup. The value of velocity with phase change is smaller than that without phase change while the temperature with phase change is bigger. The highest temperature locates in gas phase. But near the pipe wall the temperature of liquid region is higher than gas region

COMPLEX INTUITIONISTIC FUZZY DOMBI PRIORITIZED AGGREGATION OPERATORS AND THEIR APPLICATION FOR RESILIENT GREEN SUPPLIER SELECTION

One of the main problems faced by resilient supply chain management is how to solve the problem of supplier selection, which is a typical multi-attribute decision-making (MADM) problem. Given the complexity of the current decision-making environment, the primary influence of this paper is to propose the theory of Dombi operational laws based on complex intuitionistic fuzzy (CIF) information. Moreover, we examined the theory of CIF Dombi prioritized averaging (CIFDPA) and CIF weighted Dombi prioritized averaging (CIFWDPA), where these operators are the modified version of the prioritized aggregation operators and Dombi aggregation operators for fuzzy, intuitionistic fuzzy, complex fuzzy and complex intuitionistic fuzzy information. Some reliable properties for the above operators are also established. Furthermore, to state the art of the proposed operators, an application example in the presence of the invented operators is evaluated for managing resilient green supplier selection problems. Finally, through comparative analysis with mainstream technologies, we provide some mechanism explanations for the proposed method to show the supremacy and worth of the invented theory

2D/2D Heterojunction of TiO2 Nanoparticles and Ultrathin G-C3N4 Nanosheets for Efficient Photocatalytic Hydrogen Evolution

Photocatalytic hydrogen evolution is considered one of the promising routes to solve the energy and environmental crises. However, developing efficient and low-cost photocatalysts remains an unsolved challenge. In this work, ultrathin 2D g-C3N4 nanosheets are coupled with flat TiO2 nanoparticles as face-to-face 2D/2D heterojunction photocatalysts through a simple electro-static self-assembly method. Compared with g-C3N4 and pure TiO2 nanosheets, 2D/2D TiO2/g-C3N4 heterojunctions exhibit effective charge separation and transport properties that translate into outstanding photocatalytic performances. With the optimized heterostructure com-position, stable hydrogen evolution activities are threefold and fourfold higher than those of pure TiO2, and g-C3N4 are consistently obtained. Benefiting from the favorable 2D/2D heterojunction structure, the TiO2/g-C3N4 photocatalyst yields H2 evolution rates up to 3875 μmol·g with an AQE of 7.16% at 380 nm.R.D.: K.X., X.H., X.W. and C.Z. thank the China Scholarship Council for the scholarship support. IREC and ICN2 acknowledge funding from Generalitat de Catalunya, projects 2017 SGR 1246 and 2017 SGR 327, respectively. The authors thank the support from the project NANOGEN (PID2020-116093RB-C43), funded by MCIN/AEI/10.13039/501100011033/ and the project COMBENERGY (PID2019-105490RB-C32) from the Spanish Ministerio de Ciencia e Innovación. ICN2 is supported by the Severo Ochoa program from Spanish MINECO (Grant No. SEV-2017-0706) and is funded by the CERCAProgramme / Generalitat de Catalunya. Baoying Li greatly appreciates the financial support from the National Natural Science Foundation of China (Nos. 22171154 & 21801144), the Youth Innovative Talents Recruitment and the Cultivation Program of Shandong Higher Education. This study was supported by MCIN with funding from the European Union NextGenerationEU (PRTR-C17.I1), Generalitat de Catalunya and by “ERDF A way of making Europe” by the “European Union”

Genome Composition and Divergence of the Novel Coronavirus (2019-nCoV) Originating in China.

An in-depth annotation of the newly discovered coronavirus (2019-nCoV) genome has revealed differences between 2019-nCoV and severe acute respiratory syndrome (SARS) or SARS-like coronaviruses. A systematic comparison identified 380 amino acid substitutions between these coronaviruses, which may have caused functional and pathogenic divergence of 2019-nCoV

2D/2D heterojunction of TiO2 nanoparticles and ultrathin G-C3N4 nanosheets for efficient photocatalytic hydrogen evolution

Photocatalytic hydrogen evolution is considered one of the promising routes to solve the energy and environmental crises. However, developing efficient and low-cost photocatalysts remains an unsolved challenge. In this work, ultrathin 2D g-CN nanosheets are coupled with flat TiO nanoparticles as face-to-face 2D/2D heterojunction photocatalysts through a simple electrostatic self-assembly method. Compared with g-CN and pure TiO nanosheets, 2D/2D TiO/g-CN heterojunctions exhibit effective charge separation and transport properties that translate into outstanding photocatalytic performances. With the optimized heterostructure composition, stable hydrogen evolution activities are threefold and fourfold higher than those of pure TiO and g-CN are consistently obtained. Benefiting from the favorable 2D/2D heterojunction structure, the TiO/g-CN photocatalyst yields H evolution rates up to 3875 μmol·g −1 ·h −1 with an AQE of 7.16% at 380 nm