Veluru Jagadeesh Babu

Highly anisotropic titanates from electrospun TiO2–SiO2 composite nanofibers and rice grain-shaped nanostructures

We report a low temperature alkali-mediated conversion of nanofiber-and rice grain-shaped TiO2–SiO2 composites into highly anisotropic fiber (decorated with thorn-like features on surfaces)/sponge-shaped titanates of the formula Na2−xHxTi2O4(OH)2. The titanates were thoroughly characterized by spectroscopy and microscopy. Control experiments with the respective TiO2 analogues revealed that the unique open and highly porous morphologies were the result of structural rearrangement of TiO2 coupled with the in situleaching of SiO2 from the composites by the alkali. Effect of concentration of the alkali and the reaction temperature on the morphology of the titanates was also probed. Evolution of the unique morphologies from the respective starting materials was studied by scanning electron microscopy analyses of the systematically withdrawn samples during the course of the reaction. The materials utilized in dye-sensitized solar cells showed excellent photovoltaic parameters amongst the category of titanates.

Application of Poly(3‐hexylthiophene) Functionalized with an Anchoring Group in Dye‐sensitized Solar Cells

A series of three poly(3-hexylthiophene) functionalized either with a cyanoacetic acid (CA) or a rhodanine-3-acetic acid anchoring groups were synthesized and characterized. The TiO(2) based dye-sensitized solar cells have been fabricated and performances were tested. We show that shorter chain length (15 thiophene units) linked to CA binding group gives good performances as J(sc) , V(oc) , FF and η(%) were 6.93(mA · cm(-2) ), 0.65(V), 0.67 and 3.02%, respectively. A maximum IPCE of ≈50% at 500 nm was recorded with a liquid electrolyte, under AM 1.5 simulated solar irradiance.

Nitrogen-doped rice grain-shaped titanium dioxide nanostructures by electrospinning: Frequency and temperature dependent conductivity

Rice grain-shaped, nitrogen-doped titanium dioxide (N-TiO2) nanostructures are synthesized using sol-gel method and followed by electrospinning. The as-spun composite fibers are sintered at 500 °C for 1 h in air. SEM images of the sintered samples showed rice grain-shaped nanostructures. The nanostructures were made up of spherical nanoparticles with average diameters of ∼ 20 nm, and the average diameter decreased with increase of N doping level. The temperature and frequency dependent electrical characterization has carried on nanostructures using impedance spectroscopy in the range of 298 K to 498 K and 30 Hz to 7 MHz, respectively. The magnitude of the ac conductivity is obtained from Nyquist plots and is proved that the ac conductivity is strongly dependent on temperature. The activation energy (Ea) is obtained from Arrhenius plots, and it is lowered from 0.31 to 0.22 eV with increasing N content. Therefore, the rice-grain shaped nanostructures can be employed in the low temperature gas sensor applica...

Biocompatible and biodegradable elastomer/fibrinogen composite electrospun scaffolds for cardiac tissue regeneration

In this study, a mixture of elastomeric polymer poly[1,8-octanediol-co-(citric acid)-co-(sebacic acid)] or POCS and fibrinogen (FBN) was used to prepare electrospun nanofibrous scaffolds. POCS and FBN concentrations were varied; POCS:FBN: 0:100 as a control, POCS:FBN: 25:75 and POCS:FBN: 50:50. All the scaffolds were characterized by contact angle measurements, scanning electron microscopy (SEM), FTIR spectroscopy, mechanical tests, and cell proliferation studies. The contact angle measurements confirmed that the POCS:FBN: 50:50 scaffolds were hydrophilic. The scaffold diameters were confirmed by SEM to be in the range of 440 ± 120 nm. From FT-IR spectroscopy, a highly intense peak was observed at 1738 cm−1 for the scaffolds, POCS:FBN: 25:75 and POCS:FBN: 50:50, which were attributed to –CO vibrations of an ester and confirmed the presence of polyester. The Youngs modulus for the POCS:FBN: 50:50 scaffold was 0.27 ± 0.07 MPa and was comparable to native human myocardium. Cell proliferation studies by means of MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] assay were carried out on scaffolds. Human cardiomyocytes (HCMs) were seeded on the scaffolds and the interactions of the cell–scaffold constructs were evaluated. The proliferation of cardiomyocytes (CMs) on the scaffold was observed. The interactions between the cells and substrate were analyzed using confocal microscopy. The electrospun composite scaffolds of POCS/FBN showed flexibility and biodegradability. From the in vitro biocompatibility studies, it is anticipated that the scaffold POCS:FBN: 50:50 has potential for cardiac tissue regeneration.

A review on additive manufacturing and its way into the oil and gas industry

In the near future, the oil and gas industry is poised to become one of the greatest sources of revenue generation across the world. The adaptation of scalable manufacturing technology, commonly known as additive manufacturing (AM) in the oil and gas industry, offers huge potential to transfigure the way high quality 3D objects are designed, manufactured and distributed. The adoption of AM technologies in this sector also allows a high degree of freedom of design and could exponentially reduce the time taken for the product to reach the market. In this arena, AM can be a method of producing lower volume and highly efficient intricate products with various materials like polymers, metals, ceramics and their composites. Although AM has been around for several years, its adoption in this sector has been slow and limited. As it is in the initial stages, rigorous research needs to be done to standardize the materials and manufacturing process. In addition, there is a particular need to end the requirement of a finishing procedure. Continuous and significant growth has been seen since the beginning and the successful outcomes until now allow for optimism that AM has a significant role in the future of manufacturing. This review will mainly focus on ongoing efforts to bring widespread adoption of AM into highly regulated industry i.e. oil and gas, and will also identify future perspectives in this area.

A review on carbon nanotubes in biosensor devices and their applications in medicine

Abstract In recent years, integrating biological components in analytical instruments especially in biomedical research has become a prerequisite for early diagnosis of many diseases. It is well known that the material properties (electrical and physical) of CNTs is very sensitive to be affected by exposure to biomolecules and this led to the investigation by many researchers. Though the CNT-based biosensors has been widely used due their better performance, it still has many practical concerns in application. For the successful commercialization of the concept of CNT-based biosensors, many hurdles need to overcome. Modifications on CNT biosensors have experienced a dramatic change with outstanding developments. The present article provides an overview on the recent development in CNT biosensors and comprehensive analysis was given on various ways to improve the performance of CNT with new designs. In addition, some of the practical applications and concerns in the field are addressed. The scientific and technological challenges in the field are discussed in the conclusion. Graphical Abstract

Electrospun TiO 2 nanorods assembly sensitized by mercaptosuccinic acid-capped CdS quantum dots for solar cells: Subtitle as needed (paper subtitle)

CdS quantum dots (QDs) capped with mercaptosuccinic acid (MSA) as the surface passivating ligand were anchored to electrospun TiO2 nanorod surfaces using the terminal carboxylic acid groups present on MSA. The as-synthesized materials and the dye-sensitized solar cells were characterized by spectroscopy, microscopy and photocurrent measurements, respectively. Best solar cells fabricated by the method showed an efficiency of 0.07%. We believe that the simple, one-pot fabrication of the QDs and their assembly into solar cells are significant steps in QD-sensitized solar cell research.