Theoretical analysis of perching and hovering maneuvers

Unsteady aerodynamic phenomena are encountered in a large number of modern aerospace and non-aerospace applications. Leading edge vortices (LEVs) are of particular interest because of their large impact on the forces and performance. In rotorcraft applications, they cause large vibrations and torsional loads (dynamic stall), affecting the performance adversely. In insect flight however, they contribute positively by enabling high-lift flight. Identifying the conditions that result in LEV formation and modeling their effects on the flow is an important ongoing challenge. Perching (airfoil decelerates to rest) and hovering (zero freestream velocity) maneuvers are of special interest. In earlier work by the authors, a Leading Edge Suction Parameter (LESP) was developed to predict LEV formation for airfoils undergoing arbitrary variation in pitch and plunge at a constant freestream velocity. In this research, the LESP criterion is extended to situations where the freestream velocity is varying or zero. A point-vortex model based on this criterion is developed and results from the model are compared against those from a computational fluid dynamics (CFD) method. Abstractions of perching and hovering maneuvers are used to validate the low-order model's performance in highly unsteady vortex-dominated flows, where the time-varying freestream/translational velocity is small in magnitude compared to the other contributions to the velocity experienced by the leading edge region of the airfoil. Time instants of LEV formation, flow topologies and force coefficient histories for the various motion kinematics from the low-order model and CFD are obtained and compared. The LESP criterion is seen to be successful in predicting the start of LEV formation and the point-vortex method is effective in modeling the flow development and forces on the airfoil. Typical run-times for the low-order method are between 30-40 seconds, making it a potentially convenient tool for control/design applications

Comparative Analysis of Experimental and Numerical Investigation on Thermophysicalproperties in Hydro Carbon Mixtures using Jouyban-Acree Model at Various Temperatures

The thermophysical properties of liquid mixtures provide additional information regarding molecular interactions. A perusal of the literature revealed that the predictions of thermophysical properties of liquid mixtures are scarce. With an aim, the thermophysical properties of viscosity, excess molar volume VE and viscosity deviations Δη of liquid mixtures are predicted by using various nonlinear models. In this reseach Jouyban-Acree viscosity models have been used for predicting viscosity of Acetophenone with P-xylene and 1, 4 Dioxane with Benzene at different mole fractions measured at various temperatures in the atmospheric pressure condition. From experimentation excess volumes, VE, and deviations in viscosities, Δη, of mixtures at infinite dilutions have been obtained. The measured systems show positive VE and negative Δη with increasing temperatures. From the positive excess molar volume, when aromatics, which exist in a highly associated form in the pure state, are mixed with polar solvents (ketones), the monomerization occurs and new specific interactions appear in the solution.The negative viscosity deviation depends on the size and shape of the molecules and molecular interactions. These measured data tailored to the Jouyban-Acree nonlinear models to derive the binary coefficients Jouyban-Acree model is more adequate for the thermo physical and the standard deviation was found to be < 2.06 %. The molecular interactions existing between the components and comparison of liquid mixtures were also discussed

Stock And Bond Price Dynamics-Evidence From An Emerging Economy

The motivation for this study is that real stock prices are observed to overreact to changes in interest rates. The real stock prices drop when long-term interest rates rise.  It has been observed that bonds and stock prices are typically studied in isolation. The present paper attempts to analyze the dynamic linkages between stock and bond prices in India.   One of the important contributions of this study is that in India, very little/almost no work has been done to understand the dynamics of the stock and bond prices after the recent recession. The present study examined the bivariate causal relationship between stock prices and bond prices.  In the long term; i.e., periods from 2004 to 2007 and 2008 to 2009, there is no causality from stock market to bond market and vice versa. However, it is found that the bond and stock prices had a bivariate causality in the year 2009 and univariate causality in 2010. The results are interesting and support the view that excess volatility causes granger between the stock and bond markets. This can be inferred as a result of recession investors moving to bond markets and after the signs of recovery the investors might be returning to the stock markets.   It is also evident that short-term interest rates have power to forecast short-term stock returns and risk premiums on observation of co-movement between stock and bond prices. This is reiterated by many empirical studies that have shown that the term “structure of nominal interest rates” contains information potentially useful for the conduct of monetary policy

In vitro studies on Dendrobium fimbriatum Hk.F – An endangered orchid

A protocol for in vitro propagation from protocorms of Dendrobium fimbriatum a distributed in all over world and highly appreciated as an ornamental, was developed. Two different explants, entire protocorms and longitudinal halves of protocorms, were used. In addition, the effect of two different culture media, Murashige and Skoog (MS) and modified Knudson (KCm), supplemented with N6- benzyladenine (BA) (0, 0.5, 1, 2, 3, and 5 mg_L–1) and/or a-naphthalene acetic acid (NAA) at 0, 0.1, and 0.5 mg_L–1 was investigated. Adventitious shoot formation by direct organogenesis was obtained in all treatments; in some cases, the formation of protocorm like bodies was induced. Shoot formation was greater for entire protocorms; the best treatment was MS medium containing at BA 1 to 2 mg_L–1 in combination with at NAA 0.1 mg_L–1. The average height of shoots was three times greater in MS medium than in KC m medium. Sub culturing individual shoots in MS medium without plant growth regulators, but with 1 g_L–1 activated charcoal, allowed further development and rooting. An ex vitro survival rate of almost 100% was achieved. This study represents a comprehensive application for propagation, conservation, and sustainable use of this valuable natural resource

Calcification in a marginal sea - influence of seawater [Ca2+] and carbonate chemistry on bivalve shell formation

In estuarine coastal systems such as the Baltic Sea, mussels suffer from low salinity which limits their distribution. Anthropogenic climate change is expected to cause further desalination which will lead to local extinctions of mussels in the low saline areas. It is commonly accepted that mussel distribution is limited by osmotic stress. However, along the salinity gradient environmental conditions for biomineralization are successively becoming more adverse as a result of reduced [Ca2+] and dissolved inorganic carbon (CT) availability. In larvae, calcification is an essential process starting during early development with formation of the prodissoconch I (PD I) shell which is completed under optimal conditions within 2 days. Experimental manipulations of seawater [Ca2+] start to impair PD I formation in Mytilus larvae at concentrations below 3 mM, which corresponds to conditions present in the Baltic at salinities below 8 g kg-1. In addition, lowering dissolved inorganic carbon to critical concentrations (< 1 mM) similarly affected PD I size which was well correlated with calculated ΩAragonite and [Ca2+][HCO3-]/[H+] in all treatments. Comparing results for larvae from the western Baltic with a population from the central Baltic revealed significantly higher tolerance of PD I formation to lowered [Ca2+] and [Ca2+][HCO3-]/[H+] in the low saline adapted population. This may result from genetic adaptation to the more adverse environmental conditions prevailing in the low saline areas of the Baltic. The combined effects of lowered [Ca2+] and adverse carbonate chemistry represent major limiting factors for bivalve calcification and can thereby contribute to distribution limits of mussels in the Baltic Sea

Tissue culture studies on Cymbidium ensifolium (L.) Swartz

An efficient protocol for seed germination and micropropagation of Cymbidium ensifolium (L.) Swartz. was established. Four nutrient media were used for seed germination and early protocorm development: Murashige and Skoog (MS), half –strength MS, Knudson ‘C’ (KC), and Vasin and Went (VW); combinations and alone of four plant growth regulators i.e. 6-benzylaminopurine (BAP), kinetin (KN), α-napthalene acetic acid (NAA), and indole-3-butyric acid (IBA) were studied. MS medium was found as most ideal for seed germination (98±0.48) and lowest in VW (71.12 ±0.42). 3 months old protocorm were sub cultured on fresh MS medium supplemented with different concentrations of BAP, KN, NAA, and IBA alone and in combination. After 30 days highest secondary protocorms (21.25±0.63) were observed in MS medium containing BAP (4.0μM). MS medium supplemented with 8μM IBA induced the maximum roots per shoot. After 16 days of transfer to green house the survival rate was 88%

Novel framework for optimized digital forensic for mitigating complex image attacks

Digital Image Forensic is significantly becoming popular owing to the increasing usage of the images as a media of information propagation. However, owing to the presence of various image editing tools and softwares, there is also an increasing threats over image content security. Reviewing the existing approaches of identify the traces or artifacts states that there is a large scope of optimization to be implmentation to further enhance teh processing. Therfore, this paper presents a novel framework that performs cost effective optmization of digital forensic tehnqiue with an idea of accurately localizing teh area of tampering as well as offers a capability to mitigate the attacks of various form. The study outcome shows that propsoed system offers better outcome in contrast to existing system to a significant scale to prove that minor novelty in design attribute could induce better improvement with respect to accuracy as well as resilience toward all potential image threats

Biopotency of Biophytum sensitivum DC

The present study was intended to examine the antioxidant, cytotoxicity, larvicidal potentials of B. sensitivum DC. The total phenolic content was determined by the standard method described by Siddhuraju and Becker (2003). The antioxidant activity of different extracts were determined using the stable radical DPPH, phosphomolybdenum and scavenging of hydrogen peroxide assays according to the standard method. In addition, the larvicidal and cytotoxic properties of the various extract of B. sensitivum were examined. Maximum amount of extractable total phenolics was observed in methanolic extracts of B. sensitivum (1399.84 ± 215.79mg GAE/g). The best free radical (DPPH) scavenging activity of B. sensitivum was observed in acetone extracts with IC50 value 30.12µg/ml. The methanolic extracts of B. sensitivum displayed the strongest phosphomolybdenum reduction (202.24 ± 11.44 g AA/100 g) compared to other tested extracts. The methanolic extracts of B. sensitivum showed highest larval mortality in terms of lethal concentrations for 50% mortality against Culex quinquefasciatus with LC50= 215.34 mg/ml. The methanolic extract of B. sensitivum displayed most effective at 90% mortality (LC90) of brine shrimp nauplii occurred at 66.34 mg/ml Conclusion: The present investigations suggest that methanolic and acetone extracts showed a good result of antioxidant, larvicidal and cytotoxic activity. It was found that the high rates of phenolic substances widely distributed in B. sensitivum

A Study on Strengthening the Operational Efficiency of Dairy Supply Chain in Tamilnadu, India

AbstractThe main objective of this paper is to study the issues in improving the operational efficiency of the dairy supply chain in Tamil Nadu, India. Dairy Farming is a major occupation of the people of Tamil Nadu, India and it contributes a significant amount to the growth of our country. In this paper, Tamil Nadu dairy development department's objectives and its three-tier structure were studied. Through SWOT analysis its strengths, weaknesses, opportunities and threats were analyzed. In our study Tamil Nadu Cooperative Milk Producers Federation is compared with Gujarat Cooperative Milk Producers Federation (AMUL). The major issues influencing the dairy farming are studied through literature survey, field study and researchers experience. They are presented in this paper. There were three major important field studies conducted at various time periods. The data has been collected through a questionnaire method and these interactions were recorded by a video camera. Based on the research work carried out on dairy supply chain in Tamil Nadu, India, some key recommendations are made for the attention of policy makers to strengthen the operational efficiency. There are five areas of focus. They are, creation of special dairy zone, implementing dynamic milk procurement method, strengthening cooperative societies, creation of feed bank and increasing fodder productivity, integrated animal health plan and information technology