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CONTENTS YEAR 2008 Click on the linked title to view the paper
Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 7-24
Damage Propagation in Complex Biological Systems Following Exposure to Low Doses of Ionizing Radiation
Ludwig E. Feinendegen1, Herwig Paretzke2 and Ronald D. Neumann3
1. Department of Nuclear Medicine, Heinrich-Heine University, Düsseldorf, Germany; and Medical Department, Brookhaven National Laboratory, Upton, NY, USA 2. Institute of Radioprotection, Research Center for Health and Environmental Sciences (GSF), Neuherberg, Munich, Germany 3. Department of Nuclear Medicine, Clinical Center, The National Institutes of Health, Bethesda, MD, USA.
Abstract : Biological organisms contain hierarchical organization, from atoms to molecules, cells, tissues, organs, and the whole organism. Complex signaling by molecules within and between cells controls homeostasis and adaptation of the whole organism against perturbations. Energy depositions from ionizing radiation in tissue micro-masses trigger stochastically local molecular events that may result in structural damage with consequent short or long term changes in function. Damage to DNA in a tissue element increases over a certain dose range linearly with the energy deposited. This is a defined risk of DNA damage production by the energy deposition events. A second risk describes the probability of damage propagation from the primary site at the basic level of molecular organization to higher levels of the organism. This second risk depends on both quality and quantity of perturbations received at the basic level, and on the resistance by homeostatic controls against transfer of such damage. The homeostatic signaling that controls the second risk at different levels does not respond to small perturbations in a linear fashion. Moreover, protective responses under homeostatic control at the various levels of biological organization may become up-regulated temporarily and specifically by low level perturbations. These adaptive responses reflect the tolerance of homeostatic control, and, thus, also depend on “dose”. The low-dose induced temporary up-regulations of protection may operate also against non-radiogenic perturbations; for instance against those from metabolic products, such as reactive oxygen species (ROS). At single cell exposures below 0.1 Gy, adaptive protections against propagation of non-radiogenic damage often tend to outweigh permanent manifestations of radiogenic damage. The quality and extent of homeostatic responses are under genetic control. Thus, complex systems responses encompass both damage and prevention of further damage and its propagation to higher levels; they are expected to vary among individuals. The balance between health risk and benefit of low-level radiation exposure of any given individual may become predictable by gene-expression profiles in un-irradiated and irradiated tissue cells of this individual at some future time.
Key word : Damage Propagation, Biological Systems, Low Doses, Ionizing Radiation
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Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 25-32
Nanotechnology in High Performance Paint Coatings
A.S.Khanna
Corrosion Science & EngineeringIndian Institute of Technology, Bombay, India
Abstract : There is hardly any technology that has attracted an immense interest in a shortest spell of a few years. Whether it is materials development, chemistry, physics or engineering sciences, there are ample examples where nano-science or technology has created sign of positive developments. Chemical Industry has played a very important role in developing not only nano-materials but also make use of them in various applications. One field where nanotechnology has created a ripple is the paint coatings. Whether it is the improvement of chemical resistance, erosion and abrasion resistance, resistance to U.V. light, anti-fouling properties, nano-modified paints have shown great potential in several industrial applications
Key words : nano-modified paints, anti-fouling properties, high performance paint coati
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 33-44
Nuclear Medicine In 21st Millennium: An Approach Via Nanotechnology
A.L. Bhatia
University of Rajasthan Jaipur-302004; India
Abstract: Radiation techniques are an important tool in fighting against cancer and are used to treat for a variety of malignant tumors of different origins and stage; it is used in the treatment of as many as 50% of all cancer patients. The success of radiation as a cancer treatment modality stems from the facts that radiation dose can be delivered locally and that cells within the radiation field can be killed effectively. Clinical schemes of radiation therapy result from many decades of experimentation and empirical development of most effective regimes, both by laboratory researchers and clinicians. In radiotherapy, the role of nanotechnology is in offing because nanoparticles can be targeted to tumors. Thus, researchers have seized on the idea of using nanoparticles to deliver radionuclides to tumors and sparing healthy tissues from radiation-induced damage. The role of dendrimer nanocomposites in radiotherapy and imaging of the tumor microvasculature has recently been realized. Carbon nanoparticles, C-60 called buckyballs, being only a nanometer in diameter could serve as future antiradiation drugs to help protect against the side effects of cancer therapies or against dirty bombs. One way that radiation therapy and chemotherapy frequently injures cells and tissues are by producing damaging reactive oxygen species, such as free radicals, oxygen ions and peroxides. It is speculated that the electron clouds that surround buckyballs might immerse up these free radicals. Looking at several such recent developments the emerging role of nanotechnology conjointly radiation biology is quite promising.
Key words : buckyballs, dendrimer nanocomposites, radionuclides, nano-modified paints - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 45-50
Nanotechnology and Cancer Treatment
Om Pal Singh and R. M. Nehru
Atomic Energy Regulatory Board Niyamak Bhavan, Anushakti Nagar Mumbai - 400 049, India
Abstracts : Cancer is caused by damage of genes which control the growth and division of cells. Detection/diagnose/treatment is possible by confirming the growth of the cells and treated by rectifying the damaging mechanism of the genes or by stopping the blood supply to the cells or by destroying it. Conventional detection of the cancer is done by observing the physical growth/changes in the organ by X-rays and/or CT Scans and is confirmed by biopsy through cell culture. However, the limitation of these methods is that these are not very sensitive and the detection is possible only after substantial growth of the cancerous cells. Nano Particles (NP) being of a few of nano meters size and the cells being of the size of few microns, NP can enter inside the cells and can access the DNA molecules/Genes and therefore, there is a possibility that the defect in the genes can be detected. The conventional treatment options of cancer are surgery, radiation therapy and chemo therapy. However, all the these methods have their own limitations (in surgery one loses the organ and the cancer may appear again, in radiation therapy even the healthy cells get burnt, cancerous cells burning is not uniform and the burnt part may become dead and non functional, in chemotherapy treatment is harmful to healthy cells, approach is gross and rarely successful if the cancer is in advanced stage). In the nanotechnology methods, certain NP can be designed to absorb preferentially certain wave length of radiation and if they enters in the cancerous cells, they will burn them. Nanotechnology can be used to create therapeutic agents that target specific cells and deliver toxin to kill them. The NP will circulate through the body, detect cancer associated molecular changes, assist with imaging, release a therapeutic agent and then monitor the effectiveness of the intervention. In this paper, the details of these possible detection/ diagnose/ treatment methods of nanotechnology are presented. In addition the toxic effects of NP and their regulatory aspects are also discussed.
Key word : Cancer, Nanotechnology, Cantilevers, Nanopores, Nanoshells, Quantum Dotes, Health and Environmental Effects, Nanotechnology and Toxicity, Nanotechnology and Regulatory Aspects. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 51-62
Nanopharmaceuticals: An Overview
Ajay Gaur*1 and A.l. Bhatia2
1. L.B.S. College of Pharmacy, Tilak Nagar, Jaipur. 2. Center of Advanced Studies in Zoology, University of Rajasthan, Jaipur.
Abstract : Nanotechnology refers broadly to a field of applied science and technology whose unifying theme is the control of matter on the molecular level in scales smaller than 1 micrometre, normally 1 to 100 nanometers, and the fabrication of devices within that size range. As the need for the development of new medicines is pressing, and given the inherent nanoscale functions of the biological components of living cells, nanotechnology has been applied to diverse medical fields such as oncology, cardiovascular medicine and in treatment of other chronic diseases. Indeed, nanotechnology is being used to refine discovery of biomarkers, molecular diagnostics, and drug discovery and drug delivery, which could be applicable to management of these patients. The ideal nanopharmaceutical agent must be safe, biocompatible, biodegradable and stealthy-disguised well enough that the body’s immune system will not recognize it as foreign. The ultimate agent will recognize the toxic molecules, attract and bind them quickly, reduce the free drug concentration and, in the process, trigger the heart to function normally. This requires a very delicate balance between successful detoxification and preventing toxicity with the nanopharmaceuticals. Nanopharmaceuticals can act on living cells at the nanolevel resulting not only in biologically desirable, but also in undesirable effects. In contrast to many efforts aimed at exploiting desirable properties of nanopharmaceuticals for medicine, there are limited attempts to evaluate potentially undesirable effects of nanopharmaceuticals when administered intentionally for medical purposes. So, there is a pressing need for careful consideration of benefits and side effects of the use of nanopharmaceuticals. This review article aims at providing a balanced update of these exciting pharmacological and potentially toxicological developments.
Keywords : Nanopharmaceuticals, immune system, toxicological developments - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 63-74
Friction Stir Welding of Al 6061 Alloy
N. T. Kumbhar and K. Bhanumurthy
Materials Science Division Bhabha Atomic Research Centre Trombay, Mumbai - 400085. India
Abstract : Friction stir welding, a solid state joining technique, is widely being used for joining Al alloys for aerospace, marine automotive and many other applications of commercial importance. FSW trials were carried out using a vertical milling machine on Al 6061 alloy. The tool geometry was carefully chosen and fabricated to have a nearly flat welded interface. Important process parameters that control the quality of the weld are a) axial force b) rotation speed (rpm) c) traverse speed (mm/min) and d) tool tilt angle and these process parameters were optimized to obtain defect free welded joints. It is observed that, during the friction stir welding, extensive deformation is experienced at the nugget zone and the evolved microstructure strongly affects the mechanical properties of the joint. The present studies aimed to understand the microstructural changes and the associated mechanical properties during the FSW and also after post weld heat treatment (PWHT). The resultant microstructure was characterized using electron probe microanalysis (EPMA), secondary electron microscopy (SEM) and orientation imaging microscopy (OIM). This paper presents the optimization of process parameters and also highlights the influence of PWHT on the microstructure, composition variation across the interface and mechanical properties of FSW 6061 Al alloy.
Keywords: Friction stir welding, Al 6061 alloy, microstructure, mechanical properties, recrystallization. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 75-88
Hydrogen Adsorption by Carbon Nanomaterials from Natural Source
Maheshwar Sharon*1, Sunil Bhardwaj1, Sandesh Jaybhaye1, D.Sathiyamoorthy2, K.Dasgupta2 and Madhuri Sharon3
1. Nanotechnology Research Lab., Birla College, Kalyan 421304, India 2. Powder Metallurgy Division, BARC, Trombay, India 400 085 3. Monad Nanotech, 704 A-702 Bhawani Towers, Adishankaracharya Marg, Powai, Mumbai 400 076, India.
Abstract : Carbon nanomaterials are getting importance in various applications such as hydrogen storage, fuel cell, electron field emitter etc. In order to make the cost of the gadgets utilizing carbon nanomaterials economical, efforts are being made to synthesize them at lowest possible cost. In addition, most of the processes which are being developed use precursors which are derived from petroleum products, which is destined to get depleted one day. Hence, synthesis of carbon nanomaterials based on such precursors will also get depleted and the technology based on carbon nanomaterials will come to a halt. Considering these two factors, we are making efforts to search for precursors which are plant derived and could give the desired type of products at an economical rate. Another advantage of using precursors derived from plant based materials like oil seeds, plant fibers (coconut fiber or bagasse etc) is that these materials possesses different types of morphology e.g. channel type hollow cylindrical fibers, or various types of structures having various orientation of pores etc. These varied morphologies may have some useful properties like storing of hydrogen gas, intercalating of lithium etc. Moreover, such type of structure would be extremely difficult to synthesize in laboratory. In this paper, we report the utilization of some plant based fibers and some oil seeds to make carbon nanomaterial by pyrolysing them at very high temperature in an inert atmosphere, and characterize them by SEM for their morphology. It was observed that carbon nanomaterials obtained from fibers based precursors like coconut fiber; baggas etc have fibrous structure whereas carbon Nano materials formed from seeds of different plants show very complicated porous carbon structures. These carbon materials are being utilized for the application of Hydrogen Storage. In order to compare the utilities of plant derived carbon nanomaterials, acetylene and alcohol have also been used to prepare carbon Nano materials by the pyrolysis. However, unlike plant based precursors, these precursors needed suitable catalysts, which adds to the cost The fibrous carbon from Bagasse (Saccharum officinarum) gave hydrogen adsorption of 0.656 wt% at 11kg/m2 pressure of hydrogen which is nearly the same as observed with carbon nanomaterials obtained from acetylene ( 0.51 wt%), suggesting that plant derived precursors can be used for such purpose. Efforts are made and presented in this paper to discuss the role of surface area and pore sizes in facilitating hydrogen adsorption.
Key words: Carbon Nanotube, Natural Precursors, Hydrogen Adsorption, Bagasse (Saccharum officinarum) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 89-93
Carbon Nanomaterial from Tea Leaves as An Anode in LithiumSecondary Batteries
Sunil Bhardwaj1, Sandesh V. Jaybhaye1, Madhuri Sharon2, D. Sathiyamoorthy3, K. Dasgupta3, Pravin Jagadale1, Arvind Gupta1, Bhushan Patil1, Goldie Ozha1, Sunil Pandey1, T. Soga4, Rakesh Afre4, Golap Kalita5 and Maheshwar Sharon1
1. Nanotechnology Research Center, Birla College, Kalyan 421304, India. 2. Monad Nanotech Pvt Ltd. A-702 Bhavani Tower, Powai, Mumbai-76, India 3. Powder Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085, India. 4. Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan 5. Chubu University, Kasugai Aichi Japan Email : sharon@iitb.ac.in, s_p_bh@rediffmail.com
Abstract : Carbon nanomaterials have been synthesized by pyrolysis of plant based precursors (i.e. Tea leaves), without using any catalyst. These materials are characterized by SEM, Raman and XRD. Carbon nanomaterials are utilized as the anode in Li secondary batteries. The charging/discharging of the lithium batteries are studied. The carbon obtained shows the highest capacity of 63.31mAh/gm.
Keywords : Carbon nanotubes; Lithium battery carbon; Lithium intercalation. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 95-101
A Mechanism for Generation of Ultra Low-frequency Waves in the Polar Cusp Region
G. S. Lakhina
Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai-410 218, India
Abstract : Ultra low-frequency (ULF) electromagnetic waves, in the frequency range of ~1 mHz to 3 Hz, have been observed in the polar cusp and other regions of the Earth’s magnetosphere by several spacecrafts, e.g., Geotail, Polar and CLUSTER. There are strong indications that these waves are generated locally by the energetic ion beams injected during magnetic reconnection taking place at the magnetopause. Ion beams observed in the polar cusp, plasma sheet boundary layer (PSBL), and on the auroral zone field lines are expected to have spatial gradients in their drift velocity. A generation mechanism for the ULF waves is proposed in terms of kinetic Alfvén wave instability driven by velocity shear of the ion beams. The noise due to velocity shear driven Alfvén modes is electromagnetic in nature, and also has a finite parallel electric field component.
Keywords : Ultra Low-frequency Waves, Polar Cusp Region, kinetic Alfvén, plasma sheet boundary layer (PSBL) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 103-111
Chemical Sensing of Ions and Its Clinical Application
sI. Ravikumar, P. Lakshminarayanan, B. Nisar Ahamed and Pradyut Ghosh*
Department of Inorganic ChemistryIndian Association for the Cultivation of Science2A & 2B Raja S. C. Mullick Road, Kolkata 700 032, India
Abstract: Molecular fluorescent signaling is the natural interface between human and molecular domains via the intermediacy of the photon. Therefore, molecular fluorescence is one of the most visually powerful phenomena in photophysics/photochemistry. The phenomenon of molecular fluorescence processes have many features which make it particularly suitable for real-time and real-space monitoring of atomic and molecular species. Chemical sensing of ions using fluorescence technique is of considerable current interest as sensors in biomedical research. Imagine a day when blood concentrations of important analytes are determined not in a batch mode, but rather through the use of a fiber-optic bundle inserted into an artery. Development of different fluorescent sensing systems of ions along with some of the above aspects will be discussed.
Key word : Fluorescent signaling, Clinical Applications, Ions, Chemical Sensing, - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 113-115
Ionic Liquids : Environment-Friendly Solvents and Catalysts for the Future
Pralhad A. Ganeshpure
Research Centre, Reliance Industries Limited Vadodara Manufacturing Division, Vadodara 391 346
Abstract : Ionic liquids are receiving much attention as environment-friendly mediums for the organic reactions. Improvements in the rates of reaction and selectivity have been realized in many cases when ionic liquids were used in the places of the conventional solvents. Their application to esterification reaction resulted in high yields without removal of the water formed in the reaction. The esters form separate liquid phase in the reaction which are separated easily by decantation. It was demonstrated that high melting points of the ammonium salts did not prevent their use as ionic liquids in the esterification reaction.
Keywords : Ionic Liquids, Environment-Friendly, Solvents, Catalysts - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 117-121
Rajiv V. Gavai
Department of Theoretical Physics Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
Abstract : A few microseconds after the Big Bang, our Universe may have been dominated by the quark-gluon plasma (QGP), an hitherto undiscovered phase predicted by the current theory of strong interactions. Heavy ion collision experiments at very high energies at Brookhaven National Laboratory, New York and the upcoming Large Hadron Collider in CERN, Geneva have the potential for producing the right conditions for such a phase transition to occur. This introductory review of the subject endeavours to explain what quark-gluon plasma is, why it is important and how it can be created and studied in laboratory.
Keywords: quark-gluon plasma (QGP), Big Bang - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 123-140
Arpan Misra1 and Dhirendra K. Pandey2
1. AMD, Department of Atomic Energy, W.R., Jaipur-302030. 2. Department of Geology, University of Rajasthan, Jaipur-302004.
Abstract : The Kachchh Basin is a pericratonic rift basin situated at the western margin of the Indian plate. The Jumara Dome is one of the important exposures of Bathonian sediments among the Kachchh Mainland exposures. A rigorous facies analysis using the microfacies approach for the reconstruction of the depositional environment and setting of carbonate sedimentation with correlation of basin components had been lacking. Thus an important Kachchh Mainland outcrop of the Bathonian sediments (Jhurio Fm.) viz. the Jumara Dome was taken up for the present study. In accordance with the above-mentioned objectives detailed stratigraphical sections of the Jhurio Formation have been measured. Macrofacies were recorded for corroborating the microfacies data. Microfacies analysis has been carried out by studying thin- sections of rock samples under the microscope with the aim to interpret the depositional environment and setting. The study helped in the reconstruction of the depositional environment and setting at the Bathonian times represented by the Jhurio Fm. The Jhurio Fm. at the Jumara dome is characterized by well-bedded limestone-marl/marlstone alternations and massive limestones (packstones and grainstones). The sections have several units where the limestone show nodular feature. Various microfacies types are present in the Jhurio Fm. at the Jumara dome. The MF types are associated into two MF associations at the dome. A carbonate ramp setting seems to have been prevalent at the time of sedimentation of the carbonates during the Bathonian. In general, the depositional environment seems to have been a marine, open sea, mid to outer (deep) ramp environment. Depositional environment was largely low energy just below storm wave base which had seen phases of slight influence of stormevents. Reworked sediments of the transgressive phase witnessed relatively higher energy depositional environment.
Keywords : Microfacies, Depositional Environment, Bathonian, Jurassic, Pericratonic Basin, Kachchh - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 141-151
Effects of Chemical Reaction on An Isothermal Vertical Surface in Slip Flow Regime
R. C. Chaudhary1, Umesh Gupta2 and Abhay Kumar Jha3
Department of Mathematics, University of Rajasthan, Jaipur - 302004 (India)
Abstract : Combined effects of the free convection heat and mass transfer on viscous incompressible fluid flow past a vertical surface in slip flow regime has been discussed, taking into account the homogeneous chemical reaction of first order. The velocity, temperature and concentration profiles are studied for different parameters like Schmidt number, Prandtl number, thermal Grashoff number, mass Grashoff number and chemical reaction parameter and discussed with the help of graphs.
Key words : Chemical Reaction; Heat and Mass transfer; Slip Flow Regime and Suction. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 153-166
Nanotechnology: A Double Edged Sword
Shikha Patni and A.L. Bhatia
Department of Zoology, University of Rajasthan, Jaipur-300 2004; India
Abstract : Nanoscience and Nanotechnology comprise one of the fastest-growing research and development areas in the world. Nanotechnology, which refers to a technology in which materials are designed and manipulated on a molecular scale, represents a technological leap on a scale analogous to the first industrial revolution. Nanotechnology has the potential to benefit environmental quality and sustainability through pollution prevention, treatment, and remediation. However, the development and use of nanomaterials also involves a great many environmental unknowns. There is a saying that "All good fruits will turn bad", with nanotechnology destructive objects such as atomic bomb grenades, nuclear weapons, robotic killers designed to kill humans etc., can be made which can dump humanity in danger.
Key Words: Nanotechnology, Nanosciense, Molecular scale, Robotic killers - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 167-176
Oxidation of Zr-based Bulk Amorphous and Nanocrystalline Alloys
S. K. Sharma
Department of Physics Malaviya National Institute of Technology, Jaipur - 302 017, India
Abstract : Novel multicomponent Zr-based alloys like Zr-Ti-Cu-Ni-Be and Zr-Cu-Ni-Al form an important class of bulk metallic glasses with some interesting applications. Nanocrystalline forms of these alloys have been obtained by thermal annealing. Interest in bulk amorphous alloys and their nanocrystalline forms has considerably grown in recent times due to their ability to offer scope for carrying out research investigations in amorphous, supercooled liquid and nanocrystalline states of a bulk glassy alloy. Despite several studies done on the oxidation behaviour of conventional melt-spun amorphous alloys, very few studies are available on oxidation of bulk metallic glasses. The paper describes the current status of oxidation research in bulk amorphous alloys and their nanocrystalline forms obtained after annealing. Some novel results from the author's recent work carried out on oxidation of the bulk amorphous alloy Zr65Cu17.5Ni10Al7.5 in air in its amorphous and the supercooled liquid states in the temperature range 573 K- 663 K using X-ray photoelectron spectroscopy (XPS) will also be presented.
Key words : X-ray photoelectron spectroscopy, Oxidation, Zr-based Bulk Amorphous, Nanocrystalline, Alloys - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SPECIAL INVITED ARTICLE
Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 177-182
Assimilative Capacity Revisited
John Cairns, Jr.
Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
Abstract : Assimilative capacity is the ability of natural systems to assimilate humankind's wastes. Wastes (output) of some species in natural systems are the resources (input) of other species. Before the Industrial Revolution, this concept of input and output held true for human activity, but industrialization created wastes that were qualitatively and quantitatively different from those of natural systems. The unique nature of some persistent wastes that accumulate in organisms over long periods of time makes estimates of safety problematic. An even larger problem is the devastating effects that global heating and other types of climate change are having on the integrity of ecosystems. An ecosystem in disequilibrium probably has no assimilative capacity. Since greenhouse gas emissions are increasing rapidly, the already bad situation will worsen. Another factor diminishing the probability of the effective use of the assimilative capacity concept is ecological overshoot (i.e., humankind's failing to live on ecological services and using ecological capital as a substitute), which is an unsustainable practice. Biotic impoverishment (i.e., loss of biodiversity) also increases the probability of ecological disequilibrium. Finally, exponential growth of the human population, about 1.5 million additional people weekly, means a steadily increasing loss of space for natural systems and more acquisition of natural resources for human use. In short, present waste disposal practices are no longer suitable
.Key words : Assimilative capacity, Toxics accumulation, Global heating, Ecological overshoot, Exponential population growth - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - COMMENT
Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 183-186
Aruna Pandey
Department of English, University of Rajasthan, Jaipur, India
Abstract : In the global village of today the mere mention of east as east and west as west sounds like an anachronism of the past. However, although a lot of momentum has been gained in terms of technological homogeneity across different nations of the world, a lot still remains to take place in areas of cultural exchange and a true understanding of each others’ religions, social and natural environments. This could sound clickéd in the context of a fast-growing internet awareness and especially in the American melting pot situation where one nation seamlessly merges into another. It is my intention to put forward relevant observations in order to describe the cultural intensities of Germany and India—the points of divergence and convergence where both combine to enrich and enhance a comprehensive view of human life. These new understandings and awareness definitely lead us to those areas where higher truths start to form and emerge. We have indeed been a privileged community to whom the Humboldt Foundation has provided a generous platform from which to start a long and exciting journey. At this point it will make sense to mention that this journey has been an extraordinarily rewarding one in the fact that it has been shared by the members of our personal families, our spouses and children. In fact, it would not be incorrect to say that many of the most significant cultural exchanges have taken place through individual and social bonding developed by them at the time of our stay in Germany. The different areas of cultural exchange are found to reside in various institutions such as the Church and schools—in the inbuilt social system of transport and tourism and the social values built around them. In fact, the first most striking thing about the country is the fusion of the past and the present; tradition and high-tech seem to move along hand-in hand. This gets reflected not only in the beautiful architecture that simply surrounds and overpowers the first-time visitor but also in the quality of day-to-day life that the German citizen leads. My observations are based on first-hand encounters that have developed over the years to give both me and my family the insight and understanding of ourselves and others in the universal context of mankind.
Key words : Germany, internet awareness, cultural exchange, insight and understanding
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Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 187-188
Novel Waterborne Nanostructured Coatings
S. S. Pathak, A. Sharma, B. K. Jha & A. S. Khanna
Department of Metallurgical Engineering & Materials Science, Indian Institute of Technology Bombay, Powai - 400 076, India
Abstract : Paints and coatings industries are among the first to take advantage of nanotechnology by incorporation of nanoparticle in coatings or in-situ creation of nanostructured coatings. In the present study, waterborne silane based coatings for lightweight alloys (aluminum and magnesium alloy) have been developed. Lightweight alloys have the competitive advantage of modern aerospace and automotive structures because they enable achievement of high structural efficiency, improved fuel efficiency without scarifying mechanical strength. However, these alloys undergo sever corrosion when exposed to continued aggressive environment. Coatings restrict the access aggressive environmental stresses to the metal as well as interfere with metal dissolution reaction. This is the key to corrosion control by protective coating. Results show that the coatings are uniform, transparent and crack free. It is found that the corrosion current of coated substrate reduced by one to three orders of magnitude than bare substrates. UV-visible spectroscopy and UV-weathering suggest that these coatings are suitable for outdoor application. Excellent UV-resistance is observed for HMMM cure coatings and alkyd incorporated coatings. It was observed coating have no glass transition coating in the temperature range of 30-700°C. Alkyd incorporated sol-gel coating shows excellent thermal stability upto 300°C. All the coatings have shown chemical interaction with substrate which leads to their excellent adhesion. Thus, the use of nanostructure sol-gel coating and their further modification with organic polymer have to be regarded as a consistence further development of the new innovative sol-gel technology which is characterized by the combination of novel and conventional method of the formulation of coatings. These coatings are environmentally-friendly coatings of a new era of high technology for protection of material from environmental stresses and to get preferred properties.
Key words : silanes, waterborne, nanostructured coatings, UV stability - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SHORT COMMUNICATION
Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 189-191 Marsileaceae : An Amphibious Heterosporous Group of FernsThe Persisting Enigma
T. N. Bhardwaja Kota Open University Kota, India
Abstract: Marsileaceae, The heterosporous aquatic/amphibious fern family forms a central, pivotal position in botanical compendium and thought in terms of botanical conundrums and riddles like the Land ---Water Form Conversions, heterospory and the emergence of Seed Habit, Reproductive Biology features like micro- and Mega-spore differentiation, sporal aberrations in shape, size and number/sporangium, parthenogenetic/apogamous expressions, heterophylly juvenile adult leaf sequencing, leaf margin serrations-crenations, phototropic-photonastic leaf movements including nyctinasty, heliotropism and sleep-seista movements, Biological Clocks and chronobiological regulation, phytogeographic parameters like geographic Continental speciation and distribution of Marsileaceae (Cosmopolitan Marsilea, Restricted Pilularia, Endemic Regnellidium) , plant nutrition to include biological regulation of LAND-FORMàWATER-FORM conversions in response to carbohydrate nutriton/CO2 concentration/Infra-red treatment, Gametophytic regulation of sexual fertilization & genetic expression Vs Sporophytic governance.
Key words: Marsileaceae, Amphibious Heterosporous, Ferns Pilularia, Endemic Regnellidium - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - NOTES
Asian J. Exp. Sci., Vol. 22, No. 2, 2008; 193-194
Suryasarathi Bose, Arup R. Bhattacharyya*and Ajit R. Kulkarni
Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai- 400076, India
Abstract : An efficient strategy to achieve electrical conductivity in melt-mixed co-continuous blends is to restrict the conducting filler in a particular phase in the blends next to forming a percolative 'network-like' structure in that particular phase. However, strong inter-tube van der Walls' forces often hinders the formation of percolative 'network-like' structure and in addition, the migration of the conducting filler during melt-mixing and the blending sequence significantly affects the bulk conductivity of the blends. To understand these complexities we studied the electrical conductivity of melt-mixed blends of polyamide6/Ionomer with multiwall carbon nanotubes (MWNT) prepared using a conical twin-screw microcompounder. The samples for electrical conductivity measurements were prepared using a mini-injection moulded machine.
Keywords: Polymer blends, MWNT, Electrical Conductivity
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