Chitosan nanoencapsulation of Pogostemon cablin (Blanco) Benth. essential oil and its novel preservative effect for enhanced shelf life of stored Maize kernels during storage: Evaluation of its enhanced antifungal,antimycotoxin, antioxidant activities and possible mode of action

The present evaluation aimed to synthesis and characterise the Pogostemon cablin essential oil encapsulated chitosan nanoemulsion (PCEO-CN) and evaluated its antifungal antimycotoxin and antioxidant activities. A total of twenty-six different chemical compounds were identified from P. cablin essential oil (PCEO), among which patchoulol (34.93%), α-bulnesene (17.76%) and α-guaiene (15.44%) were recorded as major components. The average size of PCEO-CN was 18.20 nm. The PCEO-CN showed concentration-dependent broad-spectrum antifungal and antimycotoxin activities. The in vivo evaluation showed that PCEO-CN significantly protected maize seeds from mould-induced biodeterioration and aflatoxin B₁ biosynthesis for up to 30 days. The PCEO-CN significantly inhibits ergosterol biosynthesis and cellular integrities of A. flavus. Based on the present study, PCEO-CN could be used as a food preservative to control mould and mycotoxin contamination in stored maize.     

Simulation and optimisation studies on a solar parabolic collector: an experimental investigation

The present paper has focused on parametric optimisation of a solar parabolic collector. This work has been performed in two phases. In the first phase, simulation studies have been done to identify the influential parameters. Based on simulation results, an experimental set-up of the parabolic collector has been fabricated using the materials selected by priority-score method. In the second phase, experiments are conducted according to Taguchi's L₉ orthogonal array. Parabolic collector parameters, namely reflector materials, absorber materials, positions of the absorber tube and angle of the absorber tube, are optimised with the consideration of multi-responses such as temperature, enthalpy, optical efficiency and thermal efficiency. The obtained experimental data are analysed using the desirability functional analysis approach and optimal levels of input parameters have been identified. Analysis of variance also has been performed to know the contribution of influential parameters on the responses.     

Area-granulometry: an improved estimator of size distribution ofimage objects

The most commonly used morphological procedure for estimating size distribution of image components is the granulometry proposed by Matheron (1978). Sometimes this method requires some a priori knowledge of image component shape and fails to produce satisfactory results on certain images when the image components are non-flat. A new method (using morphological area-open) is proposed which is simple, more straightforward and the size distribution obtained is more informative     

Single step process for the synthesis of carbon nanotubes and metal/alloy-filled multiwalled carbon nanotubes

A single-step approach for the synthesis of multi-walled nanotubes (MWNT) filled with nanowires of Ni/ternary Zr based hydrogen storage alloy has been illustrated. We also demonstrate the generation of CO-free hydrogen by methane decomposition over alloy hydride catalyst. The present work also highlights the formation of single-walled nanotubes (SWNT) and MWNTs at varying process conditions. These carbon nanostructures have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), Energy dispersive X-ray analysis (EDX) and Raman spectroscopy. This new approach overcomes the existing multi-step process limitation, with possible impact on the development of future fuel cell, nano-battery and hydrogen sensor technologies.     

Reliability of a dynamic n-unit shared load parallel system under different failure times

A generalized formula is derived for the reliability of a dynamic parallel system of n-components with equally shared load failing at different failure times. This formula is obtained using success modes analysis (SMA) and the same is completely verified for exponential distribution.     

A Study on flexural properties of wildcane grass fiber-reinforced polyester composites

The main objective of this study is to introduce a new natural fiber as reinforcement in polymers for making composites. Wildcane grass stalk fibers were extracted from its stem using retting and chemical (NaOH) extraction processes. These fibers were treated with KMnO₄ solution to improve adhesion with matrix. The resulting fibers were intentionally reinforced in a polyester matrix unidirectionally, and the flexural properties of the composite were determined. The fibers extracted by retting process have a tensile strength of 159 MPa, modulus of 11.84 GPa, and an effective density of 0.844 g/cm³. The composites were formulated up to a maximum fiber volume fraction of 0.39, resulting in a flexural strength of 99.17 MPa and flexural modulus of 3.96 GPa for wildcane grass fibers extracted by retting. The flexural strength and the modulus of chemically extracted wildcane grass fiber composites have increased by approximately, 7 and 17%, respectively compared to those of composites made from fibers extracted by retting process. The flexural strength and the modulus of KMnO₄-treated fiber composites have increased by 12 and 76% over those of composites made from fibers extracted by retting process and decreased by 3 and 48% over those of composites made from fibers extracted by chemical process, respectively. The results of this study indicate that wildcane grass fibers have potential as reinforcing fillers in plastics in order to produce inexpensive materials with high toughness.     

Development of Gelatin Based Inorganic Nanocomposite Hydrogels for Inactivation of Bacteria

In this investigation, silver nanocomposite hydrogels were developed by using acrylamide and biodegradable gelatin. Silver nanoparticles were generated throughout the hydrogel networks using in situ method by incorporating Ag⁺ ions and the subsequent treatment with sodium borohydride. The effect of gelatin on the swelling studies was investigated. The hydrogel synthesized silver nanocomposites were characterized by using Fourier transform infrared, UV–Visible spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron and transmission electron microscopy techniques. The biodegradable gelatin-based silver nanocomposite hydrogels were tested for antibacterial properties. The results indicate that these biodegradable silver nanocomposite hydrogels can be useful in medical applications, as antibacterial agents.     

An efficient short-term energy management system for a microgrid with renewable power generation and electric vehicles

Neural Computing and Applications - According to statistical reports, thermal power plants have long played a critical role in supplying electricity using fossil fuels. However, due to the high...     

Versatile multi-decade CMOS voltage-controlled oscillator with accurate amplitude and pulse width control

A compact, versatile and very high speed approach for waveform generation is introduced. It generates triangle and square waveforms. The VCO has a very wide range of oscillating frequencies, from fractions of Hz to 30 MHz in 0.5 μm CMOS technology. The amplitude of the oscillations can be very precisely controlled. It has linear control over frequency, amplitude and pulse-width. It can be used in frequency, amplitude and pulse-width modulation applications as well as in the accurate piecewise linear waveform synthesis. Experimental results of a MOSIS CMOS AMI 0.5 μm technology test chip are presented that validate the proposed circuit.     

Nanomechanics of biomolecules: focus on DNA

Nano-mechanical measurements and manipulations at the single-cell and single-molecular levels using the atomic force microscope (AFM) and optical tweezers are presenting fascinating opportunities to the researchers in bioscience and biotechnology. Single molecule biophysics technologies, due to their capability to detect transient states of molecules and biomolecular complexes, are the methods of choice for studies in DNA structure and dynamics, DNA-DNA and DNA-protein interactions, and viral DNA packaging. The aim of this review is to describe the recent developments of scientific tools and the knowledge gained in single molecule DNA mechanics such as DNA elasticity, electrostatics, condensation and interactions of DNA with surrounding fluids during its hydrodynamic flow. This paper was presented at the 9^th Asian International Conference on Fluid Machinery (AICFM9), Jeju, Korea, October 16–19, 2007.recommended for publication in revised form by Associate Editor In-Ha Sung Y. Eugene Pak is currently serving as the Director of Research Planning Team at the Advanced Institute of Convergence Technology in Seoul National University. He received B.S. degree in Mechanical Engineering from the State University of New York at Buffalo in 1980, and M.S. and Ph.D. degrees in Mechanical Engineering from Stanford University in 1982 and 1985, respectively. After obtaining the Ph.D. degree, he worked as Senior Research Scientist at Northrup-Grumman Corporate Research Center. He joined the Samsung Advanced Institute of Technology (SAIT) in 1995 and has since been leading and expanding research programs in MEMS, Nano and Biotechnology. Sanghyo Kim received B.S. degree in Polymer Science and Engineering from Pusan National University in 1986. He then went on to receive his M.S. and Ph.D. degrees from POSTECH in 1992 and1996, respectively. After the Ph.D. degree, he worked as Senior Researcher at University of Sheffield, UK and University of Cincinnati, USA. He joined the Samsung Electronics Ltd. as a principal researcher in 2002. Dr. Kim is currently an Assistant Professor at the College of Bionano Technology, Kyungwon University in Gyeonggi, Korea. His research interest is in the area of pervasive healthcare information technology including ubiquitous healthcare system and cell/tissue based lab-on-a-chip. Mohana Marimuthu received her Bachelor degree in Pharmacy from The TamilNadu Dr. M.G.R Medical University, India, in 2007. She worked as a clinical study coordinator in phase III clinical trials (Asthma and Chronic Obstructive Pulmonary Disease) at pulmonary department in Sri Ramakrishna Hospital and Institute of Health science, India until February 2008. She is currently doing final year M.S degree in Bionanotechnology at Kyungwon University, Korea. Her research interests extend into microfluidics, tissue engineering and drug delivery.