There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Semiconductor photocatalysis has received much attention as a potential solution to the worldwide energy shortage and for counteracting environmental degradation. This article reviews state-of-the-art research activities in the field, focusing on the scientific and technological possibilities offered by photocatalytic materials. We begin with a survey of efforts to explore suitable materials and to optimize their energy band configurations for specific applications. We then examine the design and fabrication of advanced photocatalytic materials in the framework of nanotechnology. Many of the most recent advances in photocatalysis have been realized by selective control of the morphology of nanomaterials or by utilizing the collective properties of nano-assembly systems. Finally, we discuss the current theoretical understanding of key aspects of photocatalytic materials. This review also highlights crucial issues that should be addressed in future research activities.

Nano‐photocatalytic Materials: Possibilities and Challenges

Rising atmospheric levels of carbon dioxide and the depletion of fossil fuel reserves raise serious concerns about the ensuing effects on the global climate and future energy supply. Utilizing the abundant solar energy to convert CO2 into fuels such as methane or methanol could address both problems simultaneously as well as provide a convenient means of energy storage. In this Review, current approaches for the heterogeneous photocatalytic reduction of CO2 on TiO2 and other metal oxide, oxynitride, sulfide, and phosphide semiconductors are presented. Research in this field is focused primarily on the development of novel nanostructured photocatalytic materials and on the investigation of the mechanism of the process, from light absorption through charge separation and transport to CO2 reduction pathways. The measures used to quantify the efficiency of the process are also discussed in detail.

Photocatalytic reduction of CO2 on TiO2 and other semiconductors.

Global warming and climate change concerns have triggered global efforts to reduce the concentration of atmospheric carbon dioxide (CO2). Carbon dioxide capture and storage (CCS) is considered a crucial strategy for meeting CO2 emission reduction targets. In this paper, various aspects of CCS are reviewed and discussed including the state of the art technologies for CO2 capture, separation, transport, storage, leakage, monitoring, and life cycle analysis. The selection of specific CO2 capture technology heavily depends on the type of CO2 generating plant and fuel used. Among those CO2 separation processes, absorption is the most mature and commonly adopted due to its higher efficiency and lower cost. Pipeline is considered to be the most viable solution for large volume of CO2 transport. Among those geological formations for CO2 storage, enhanced oil recovery is mature and has been practiced for many years but its economical viability for anthropogenic sources needs to be demonstrated. There are growing interests in CO2 storage in saline aquifers due to their enormous potential storage capacity and several projects are in the pipeline for demonstration of its viability. There are multiple hurdles to CCS deployment including the absence of a clear business case for CCS investment and the absence of robust economic incentives to support the additional high capital and operating costs of the whole CCS process.

https://www.elsevier.com/__data/assets/pdf_file/0005/96980/Current-status-carbon-capture.pdf

An overview of current status of carbon dioxide capture and storage technologies

A review on g-C3N4-based photocatalysts

Swift heavy ion irradiation is an effective technique to induce changes in the microstructure and electronic energy levels of materials leading to significant modification of properties. Here we report enhancement of ammonia (NH3) sensitivity of SnO2 thin films subjected to high-energy Ni+ ion irradiation. Sol-gel-derived SnO2 thin films (100nm thickness) were exposed to 75 MeV Ni+ ion irradiation, and the gas response characteristics of irradiated films were studied as a function of ion fluence. The irradiated films showed p-type conductivity with a much higher response to NH3 compared to other gases such as ethanol. The observed enhancement of NH3 sensitivity is discussed in context of ion beam generated electronic states in the SnO2 thin films.

/pdf/enhancement-of-ammonia-sensitivity-in-swift-heavy-ion-allx23pw1a.pdf

Enhancement of ammonia sensitivity in swift heavy ion irradiated nanocrystalline SnO 2 thin films

An unusual half-open cubane-like tetranuclear copper(II) complex supported by both μ-alkoxo and μ3-hydroxo bridges: Structure, magnetic properties, EPR and DFT studies

Hydrothermal temperature-controlled size and distribution of CeO2 nanoparticles over TiO2 nanorods: Heterojunction characteristics and photoelectrochemical performance

The present work reports numerical simulations of blood flow patterns and wall shear stress (WSS) distributions in stenotic arteries, modelled as straight tubes. Inflow waveforms have been generated for different pulse rates considering constant volumetric flow during each pulsation cycle and a two-element windkessel model has been used to specify the outlet pressure. It is noticed that the non-Newtonian shear thinning rheology of blood produces more accurate and realistic predictions of the flow field as compared to the Newtonian assumption. Further, the effects of variation of pulse rates on the spatial and temporal distribution of WSS and oscillatory shear index (OSI) have also been studied for both axisymmetric and asymmetric stenosis. The changes in the mean flow features due to changes in pulsation frequencies have also been reported.

Effect of pulse rate variation on blood flow through axisymmetric and asymmetric stenotic artery models.

Quantification of Blood Clotting Kinetics I: Determination of Activated Clotting Times as a Function of Heparin Concentration Using Magnetoelastic Sensors

Somnath C. Roy

Papers

Enhancement of ammonia sensitivity in swift heavy ion irradiated nanocrystalline SnO 2 thin films

An unusual half-open cubane-like tetranuclear copper(II) complex supported by both μ-alkoxo and μ3-hydroxo bridges: Structure, magnetic properties, EPR and DFT studies

Hydrothermal temperature-controlled size and distribution of CeO2 nanoparticles over TiO2 nanorods: Heterojunction characteristics and photoelectrochemical performance

Effect of pulse rate variation on blood flow through axisymmetric and asymmetric stenotic artery models.

Quantification of Blood Clotting Kinetics I: Determination of Activated Clotting Times as a Function of Heparin Concentration Using Magnetoelastic Sensors