Fractal and Multifractal Analysis of the Rise of Oxygen in Earth's Early Atmosphere

The rise of oxygen in Earth's atmosphere that occurred 2.4 to 2.2 billion years ago is known as the Earth's Great Oxidation, and its impact on the development of life on Earth has been profound. Thereafter, the increase in Earth's oxygen level persisted, though at a more gradual pace. The proposed underlying mathematical models for these processes are based on physical parameters whose values are currently not well-established owing to uncertainties in geological and biological data. In this paper, a previously developed model of Earth's atmosphere is modified by adding different strengths of noise to account for the parameters' uncertainties. The effects of the noise on the time variations of oxygen, carbon and methane for the early Earth are investigated by using fractal and multifractal analysis. We show that the time variations following the Great Oxidation cannot properly be described by a single fractal dimension because they exhibit multifractal characteristics. The obtained results demonstrate that the time series as obtained exhibit multifractality caused by long-range time correlations.Comment: 20 pages, 3 figures, 3 tables; Chaos, Solitons & Fractals (in press

Chemical Modification of Wood

Wood is, perhaps, nature's most wonderful gift to humanity, its versatile character providing unlimited scope for property manipulation and product development to suit diverse applications. Progress in the field of polymer chemistry led to the development of a new class of wood products with substantially improved physical, chemical, mechanical, and biological properties. Aesthetic superiority, uniform finish, property enhancement, and reduced maintenance made modified wood attractive for large-scale application in many industrial uses as substitutes for costly metals and alloys.Chemical modification of the cell wall achieved significant success during the last two decades. A wide variety of wood modification reactions have been studied, of which acetylation holds great potential. Improved dimensional stability and resistance to biological degradation have made it attractive for use in high-value panels and joinery products. The high resistance to biodegradation, especially with bonded biocides, holds a bright future for its use in wood protection in view of increasing environmental controls to limit pollution of the planet Earth.Improvement in dynamic mechanical properties of wood, resulting from bulking of the cell wall, shows promise for its utilization in the manufacture of improved musical instruments

Bibliometric mapping of Research Productivity of TIFR Mumbai as seen through the mirror of Web of Science

The paper reveals the research productivity of the scientist of Tata Institute of Fundamental Research (TIFR), Mumbai, India during the year 2001-2015. The study is an analysis of total productivity of TIFR with comparing its Astronomical research productivity during the year 2001-2015. Web of Science (WoS) database was used for the bibliographic data retrieval. Bibliographic data were analyzed by using bibliometric tools and techniques. The research is conducted with a purpose to know the total research productivity of TIFR as well as Astronomical productivity over the period of 15 years (2001-2015), the literature growth, document types, the citations received, source journals, collaborating institutions & countries and research funding agencies. Findings also indicate the publication pattern, CAGR, degree of collaboration, H-Index as well as the nature of the research activities carried out

Numerical solution of ocular fluid dynamics

Numerical calculations of the aqueous humor dynamics in the anterior chamber of both the rabbit and the human eye are presented to delineate the basic flow and transport mechanisms. The calculations are based on a geometrical model of the eye, which represents the Trabecular mesh (TM) as a multi-layered porous zone of specified pore sizes and void fraction. Buoyancy is observed to be the dominant driving mechanism for the convective motion in both orientations (horizontal and vertical) of the eye. Reducing the TM pore size does not appear to have a significant influence on the intra-ocular pressure (IOP) until the pore size drops below 1 micron beyond which a significant increase in IOP is observed. Simulations of particle transport are also performed to gain insight about the movement and deposition of particles of different characteristics and to identify the mechanisms for the development of observed pathological structures. Simulations predict the formation of Krukenberg Spindle through pigment cell deposition on the corneal surface. Simulation of heavy particles present in the AH show that they gravitate inside the eye and a layered structure is formed at the bottom of the anterior chamber. The simulated particle deposition patterns are seen to correspond with clinical observations. The development of elevated pressure in the eye with pupillary block is simulated and analyzed. Potential surgical procedures (iridectomy) are simulated through virtual opening of holes at different positions along the iris disk. The effect of the location of holes along the iris surface is analyzed for single and two hole iridectomy. Key issues considered in analyzing the results are (a) reduction in IOP, (b) the asymmetry introduced in the flow profile, (c) adequate circulation of the flow in the different region since the flow provides the nutrition to the tissues and (d) the particle deposition on the ocular tissues. It is observed that when a single hole is created, the 12 o’clock iridectomy provides better results than the other locations. The preferred arrangement with the two-hole iridectomy is the 9 o’clock and 3 o’clock positions since the flow distribution is most symmetrical and circulation is the strongest