Rameshwar Adhikari

Functionalisation of bamboo and sisal fibres cellulose in ionic liquids

Abstract The aim of this work is to study the morphological changes after alkali treatment and functionalisation of cellulosic materials present in crude bamboo and sisal flours using ionic liquid as solvents. The flours of bamboo (BF) and sisal (SF) were subjected to acetylation and silylation using acetic anhydride (AA) and hexamethyldisilazane (HMDS) as reagents. The changes in fibres structure and morphology were studied by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) respectively. The results indicate that crude BF and SF are functionalised successfully which is confirmed by FTIR spectra and the solubility of the derivatives in different solvents. The microscopic structures of the cellulose microfibre bundles become more distinct after delignification

Ayurvedic Bhasmas: overview on nanomaterialistic aspects, applications, and perspectives.

In this paper, we present an overview of Ayurvedic Bhasmas as nanomedicine of herbo-metallic and mineral origin with particular attention to their structural aspects. We find, the Bhasmas as nanomedicines may offer a huge potential for designing new drugs employing the concept of nanotechnology. Thus, the standardization of fabrication process of these formulations is a crucial issue to be addressed. The structure and effectiveness of the Bhasmas as drugs depend largely on their processing history. Bhasmas are generally safe drugs for human beings in spite of the presence of seemingly toxic elements and compounds as indicated by recent studies using modern analytical techniques. Nevertheless, more systematic nanomaterialistic investigations on Bhasmas are recommended for gaining the complete and reliable composition-processing-structure-effectiveness picture of these drugs.

Functionalised SIS triblock copolymer elastomer and its nanocomposites: synthesis and characterisation

Abstract Polystyrene-block-polyisoprene-block-polystyrene (SIS) triblock copolymer was modified into an epoxidised version (ESIS) using performic acid. The ESIS was further acrylated to prepare the acrylated version (ASIS). The nanocomposites of each sample (SIS, ESIS and ASIS) were prepared using boehmite nanofiller via solution casting, which were characterised by Fourier transform infrared spectroscopy and transmission electron microscopy (TEM). The TEM investigations revealed that the epoxidation of the diene block enhanced the dispersion of the nanofiller in polymer matrix, which may be attributed to the improved compatibility between alkybenzene sulphonic acid coated inorganic filler and polar modified middle block of the copolymer. The segregation of the nanoparticles towards the interface of different microscopically segregated polymer domains was observed in the acrylated block copolymer based nanocomposite implying the incomplete acrylation of the block copolymer, which might segregate from the bulk unmodified or partially modified polymer.

Living Under the Threat of Earthquakes

Earthquakes are catastrophes that affect all parts of a society and a country. Consequently, they have to be examined integratively and measures of restoration and precaution have to include not only safer rebuilding and damage minimization but many more fields, such as economy, infrastructure or social structure of the society. Using the example of the Gorkha 2015 earthquake in Nepal, geoscientific, technical, medical, economic, social, political and legislative aspects of such a catastrophe are presented and discussed in detail as well as with respect to the special situation in a developing country. Particularly, the connections and interactions between all these fields are emphasized. In addition, suggestions are presented, in which way preparedness of the society on all levels of technical and medical precaution, administration, politics and not least with respect to culture and social structure can be reached and resilience towards future earthquakes and other catastrophes can be increased.

Earthquakes as Events of Inter- and Intra-disciplinary Character—With Special Reference to the Gorkha 2015 Earthquake in Nepal

Earthquakes are catastrophes that affect all parts of a society and a country. Consequently, they have to be examined integratively and measures of restoration and precaution have to include not only safer rebuilding and damage minimization but many more fields, such as economy, infrastructure or social structure of the society. Using the example of the Gorkha 2015 earthquake in Nepal, geoscientific, technical, medical, economic, social, political and legislative aspects of such a catastrophe are presented and discussed in detail as well as with respect to the special situation in a developing country. Particularly, the connections and interactions between all these fields are emphasized. In addition, suggestions are presented, in which way preparedness of the society on all levels of technical and medical precaution, administration, politics and not least with respect to culture and social structure can be reached and resilience towards future earthquakes and other catastrophes can be increased.

Atomic Force Microscopy as a Nanoanalytical Tool

Abstract Atomic force microscopy (AFM), also commonly known as scanning force microscopy, has evolved as an extremely useful tool for the study of the structure and properties of nanostructured systems including nanoparticles (NPs), composites, and soft matters such as polymers and biological tissues. In particular, AFM serves as an excellent complement to electron microscopic techniques, on one hand, and represents a unique tool to study the physical and functional properties of heterogeneous systems on the nanoscale on the other. The aim of this chapter is to elucidate the contribution of AFM to the structural characterization of nanomaterials with an introduction to the principles of the basic AFM techniques and sample preparation methods. A comparison with electron microscopy will also be presented, selecting some illustrative examples of imaging of NPs, soft matter, and composites. We demonstrate that AFM can conveniently be used not only to image the morphology of the materials with nanometer resolution but also to gain insight into the manipulation of the NPs in a controlled manner.

Scanning Electron Microscopy, ESEM, and X-ray Microanalysis

Abstract The chapter gives a brief summary of the principles, advantages, and applications of scanning electron microscopy (SEM) and electron probe-based X-ray microanalysis (EDX). The focus is put on practical aspects, as there are issues of sample preparation and mechanisms of signal detection and contrast generation that should enable users to define the problems and interpret the results adequately. Further on, the advantages of environmental (or variable pressure) SEM are discussed. The general part is completed with a number of examples from different groups of materials. Finally, an overview of recent developments toward ultrahigh-resolution SEM and new mechanisms of contrast enhancement is given, covering interactions and specific advantages obtained by low-voltage techniques in combination with a new generation of signal detectors, especially the so-called inlens detectors.