Andhra University or Andhra Viswa Kala Parishad , located in Visakhapatnam, north east coastal Andhra Pradesh, is one of the older premier universities in India with a broad focus. Presently it is among the top universities in India for Engineering, Science and Economics. It was established in 1926 and shared affiliating responsibilities with Madras University in the initial years.It is highly rated by NAAC with A rating with a score of 3.65 out of 4. The University designed and implemented Quality Management System successfully and became the first general University in the country to get ISO 9001: 2000 Certification in 2006. Wikipedia.
Vaisakh K.,Andhra University
Electric Power Systems Research | Year: 2013
In this paper, a novel metaheuristic optimization methodology is proposed to solve large scale nonconvex economic dispatch problem. The proposed approach is based on a hybrid shuffled differential evolution (SDE) algorithm which combines the benefits of shuffled frog leaping algorithm and differential evolution. The proposed algorithm integrates a novel differential mutation operator specifically designed to effectively address the problem under study. In order to validate the SDE methodology, detailed simulation results obtained on three standard test systems 13, 40, and 140-unit test system are presented and discussed. Transmission losses are considered along with valve point loading effects for 13 and 40-unit test systems and calculated using B-coefficient matrix. A comparative analysis with other settled nature-inspired solution algorithms demonstrates the superior performance of the proposed methodology in terms of both solution accuracy and convergence performances. © 2012 Elsevier B.V.
Prema Kumar N.,Andhra University
International Journal of Electrical Power and Energy Systems | Year: 2013
Distributed generation (DG) sources are predicated to play major role in distribution systems due to the demand growth for electrical energy. Location and sizing of DG sources found to be important on the system losses and voltage stability in a distribution network. In this paper an efficient technique is presented for optimal placement and sizing of DGs in a large scale radial distribution system. The main objective is to minimize network power losses and to improve the voltage stability. A detailed performance analysis is carried out on 33-bus, 69-bus and 118-bus large scale radial distribution systems to demonstrate the effectiveness of the proposed technique. Performing multiple power flow analysis on 118-bus system, the effect of DG sources on the most sensitive buses to voltage collapse is also carried out. © 2012 Elsevier Ltd. All rights reserved.
Vaisakh K.,Andhra University
International Journal of Electrical Power and Energy Systems | Year: 2013
This paper proposes a novel metaheuristic optimization methodology aimed at solving economic dispatch problem considering valve point loading effects. The proposed approach is based on a hybrid shuffled differential evolution (SDE) algorithm which combines the benefits of shuffled frog leaping algorithm and differential evolution. The SDE algorithm integrates a novel differential mutation operator specifically designed to effectively address the problem under study. In order to validate the proposed methodology, detailed simulation results obtained on three standard test systems are presented and discussed. A comparative analysis with other settled nature-inspired solution algorithms demonstrates the superior performance of the proposed methodology in terms of both solution accuracy and convergence performances. © 2012 Elsevier Ltd. All rights reserved.
Sudha K.R.,Andhra University |
Vijaya Santhi R.,Andhra University
International Journal of Electrical Power and Energy Systems | Year: 2012
The transient behavior of many large scale systems is heavily influenced by perturbations and in particular, usually, due to changes in operating points. Load Frequency Control (LFC) in power systems is very important in order to supply reliable electric power with good quality. The goal of LFC is to maintain zero steady state errors for frequency deviations in each control area. Several control strategies, such as classical control, optimal control, suboptimal control, adaptive control, variable structure control etc. have been employed in the past to explore an optimum controller for LFC. In practice LFC systems use simple Proportional Integral (PI) controllers, Proportional Integral Derivative (PID) controllers etc. This paper presents a method based on Type-2 Fuzzy System (T2FS) for Load frequency control (LFC) of power systems including Superconducting magnetic energy storage (SMES) units of a two-area interconnected reheat thermal system. This paper proposes a Type-2 (T2) fuzzy approach for load frequency control of two-area interconnected reheat thermal power system with the consideration of Generation Rate Constraint (GRC), Boiler Dynamics (BD) and SMES. The salient advantage of this controller is its high insensitivity to large load changes and plant parameter variations even in the presence of non-linearities. The proposed method is tested on a two-area power system to illustrate its robust performance with various area load changes. The performance of the Type-2 (T2) fuzzy controller is compared with optimal PID (Khamsum's optimal PID) controller and Fuzzy PI Controller (Type-1 Fuzzy) controller in the presence of GRC, BD and SMES. Simulation results confirm the high robustness of the proposed SMES controller with small power capacity against various disturbances and system uncertainties in comparison with SMES in the previous research. © 2012 Elsevier Ltd. All rights reserved.
Sudha K.R.,Andhra University |
Vijaya Santhi R.,Andhra University
International Journal of Electrical Power and Energy Systems | Year: 2011
The Load Frequency Control (LFC) problem has been a major subject in electrical power system design/operation. LFC is becoming more significant recently with increasing size, changing structure and complexity in interconnected power systems. In practice LFC systems use simple Proportional Integral (PI) controllers. As the PI control parameters are usually tuned, based on classical approaches. Moreover, they have fixed gains; hence are incapable of obtaining good dynamic performance for a wide range of operating conditions and various load changes, in multi-area power system. Literature shows that fuzzy logic controller, one of the most useful approaches, for utilizing expert knowledge, is adaptive in nature and is applied successfully for power system stabilization control. This paper proposes a Type-2 (T2) fuzzy approach for load frequency control of two-area interconnected reheat thermal power system with the consideration of Generation Rate Constraint (GRC). The performance of the Type-2 (T2) controller is compared with conventional controller and Type-1 (T1) fuzzy controller with regard to Generation Rate Constraint (GRC). The system parametric uncertainties are verified by changing parameters by 40% simultaneously from their typical values. © 2010 Elsevier Ltd. All rights reserved.
Senthilkumaran B.,Andhra University
Frontiers in Bioscience | Year: 2011
Meiotic maturation is a complex process that involves resumption of meiosis in response to preovulatory luteinizing hormone (LH) surge just before ovulation. High levels of cAMP in oocytes maintain meiotic arrest at diplotene of prophase I in mammals and pisces. In mammals, the process by which LH induces recommencement of meiosis involves breakdown of oocyte-somatic cells communication, which is followed by a drop in intracellular cAMP levels that in turn causes exit from meiotic arrest. Maturation promoting factor (MPF) then accomplishes progression of oocytes to reach first metaphase followed by second metaphase after reinitiating meiosis. Pisces require precise completion of oocyte growth involving vitellogenesis before the entry of meiotic maturation. Then, both mammalian and fish oocytes enters resumption of meiosis involving germinal vesicle breakdown, chromosome condensation, assembly of meiotic spindle, and formation of first polar body. However, this process in pisces is regulated by three major mediators, LH, 17alpha,20beta-dihydroxy progesterone and MPF which are unique. The molecular mechanisms of meiotic maturation and ovulation by comparing mammalian and piscine research have been dealt in this review.
Subba Rao N.,Andhra University
Environmental Monitoring and Assessment | Year: 2011
Fluoride (F-) is essential for normal bone growth, but its higher concentration in the drinking water poses great health problems and fluorosis is common in many parts of India. The present paper deals with the aim of establishment of facts of the chemical characteristics responsible for the higher concentration of F- in the groundwater, after understanding the chemical behavior of F- in relation to pH, total alkalinity (TA), total hardness (TH), carbonate hardness (CH), non-carbonate hardness (NCH), and excess alkalinity (EA) in the groundwater observed from the known areas of endemic fluorosis zones of Andhra Pradesh that have abundant sources of F --bearing minerals of the Precambrians. The chemical data of the groundwater shows that the pH increases with increase F-; the concentration of TH is more than the concentration of TA at low F- groundwater, the resulting water is represented by NCH; the TH has less concentration compared to TA at high F- groundwater, causing the water that is characterized by EA; and the water of both low and high concentrations of F- has CH. As a result, the F- has a positive relation with pH and TA, and a negative relation with TH. The operating mechanism derived from these observations is that the F- is released from the source into the groundwater by geochemical reactions and that the groundwater in its flowpath is subjected to evapotranspiration due to the influence of dry climate, which accelerates a precipitation of CaCO3 and a reduction of TH, and thereby a dissolution of F-. Furthermore, the EA in the water activates the alkalinity in the areas of alkaline soils, leading to enrichment of F-. Therefore, the alkaline condition, with high pH and EA, and low TH, is a more conducive environment for the higher concentration of F- in the groundwater. © 2010 Springer Science+Business Media B.V.
Chaitanya K.,Andhra University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012
The FT-IR (4000-450 cm -1) and FT-Raman spectra (3500-100 cm -1) of benzophenone 2,4-dicarboxylic acid (2,4-BDA) have been recorded in the condensed state. Density functional theory calculation with B3LYP/6-31G(d,p) basis set have been used to determine ground state molecular geometries (bond lengths and bond angles), harmonic vibrational frequencies, infrared intensities, Raman activities and bonding features of the title compounds. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of 2,4-BDA is calculated using HF/6-31G(d,p) method on the finite-field approach. The stability of molecule has been analyzed by using NBO analysis. The calculated first hyperpolarizability shows that the molecule is an attractive molecule for future applications in non-linear optics. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. Mulliken population analysis on atomic charges is also calculated. Because of vibrational analyses, the thermodynamic properties of the title compound at different temperatures have been calculated. Finally, the UV-vis spectra and electronic absorption properties were explained and illustrated from the frontier molecular orbitals. © 2011 Elsevier B.V. All rights reserved.
Al-Dawody M.F.,Andhra University |
Bhatti S.K.,Andhra University
Energy Conversion and Management | Year: 2013
In this study the combustion, performance and emission parameters of single cylinder, four stroke, constant speed diesel engine operating on diesel oil and different blends of soybean methyl ester (SME) have been investigated experimentally and also theoretically using the simulation software Diesel-rk. It was found that 25.27%, 36.93%, and 52.96% reduction in the Bosch smoke number is obtained with B20% SME, B40% SME and B100% SME respectively, as compared to pure diesel fuel. All blends of biodiesel are observed to emit higher NOx emissions relative to that of nominal diesel level. The results point out that B20% SME was the best one which gives little performance differences with good reduction in emissions when compared to diesel fuel. Different strategies are adopted to control biodiesel NOx effect on the B20% SME. From the one dimensional strategy it is observed that cooling air temperature from (55 to 15) °C reduce NOx, air pollutant emissions (SE), Bosch smoke number and brake specific fuel consumption (BSFC) by 10.53%, 17.63%, 24.35%, and 6.2% respectively with respect to base line operation. Deeper piston bowel with small diameter gives a significant reduction in the NOx emissions. According to scanning 2-dimensional strategy it is found that the best reduction in the NOx, air pollutant emissions and Bosch smoke number is 22.84%, 20.2%, and 8.31% respectively while BSFC is increased by 5.14% at 19 compression ratio and 0.06 exhaust gas recirculation ratio (EGR). A multiparametric optimization technique using Rosenbrok method for diesel engine operating on B20% SME was investigated theoretically. The optimization gives 50.26% reduction in NOx emissions. The theoretical simulation results are verified with the experimental study conducted at the same operating conditions. © 2013 Elsevier Ltd. All rights reserved.
News Article | February 23, 2017
A few years ago, Christopher Hamm was reading up on monarch butterflies when he noticed something peculiar. All of the scientific articles that mentioned the number of the insect’s chromosomes—30, it seemed—referenced a 2004 paper, which in turn cited a 1975 paper. But when Hamm, then a postdoc at the University of Kansas in Lawrence, did a genetic analysis of his own, he found that his monarchs only had 28 chromosomes, suggesting that an error has pervaded the literature for more than 40 years. Another twist, however, was just around the corner. Hamm suspected a mistake when he read the original 1975 paper. The authors, biologists N. Nageswara Rao and A. S. Murty at Andhra University in Visakhapatnam, India, had studied what they claimed was an Indian monarch butterfly in their work. But there’s a problem: Monarchs are nearly exclusively a North American species. “It’s implied they just went outside their building and collected some butterflies,” Hamm says. “I immediately thought, ‘Monarch butterflies in India? Really?’” Sure monarchs are master travelers, with the longest-known seasonal migration of any insect. And it’s not uncommon for a few to get blown off course to Australia, the Philippines, the United Kingdom, and a handful of other places from time to time. But ending up as far away as India seemed like a stretch. Hamm, now a data scientist at Monsanto in Woodland, California, also knew that taxonomists since Carl Linnaeus have struggled to distinguish species in Lepidoptera, the order of insects to which monarchs belong. For example, the monarch (Danaus plexippus) and a similar-looking butterfly known as the common tiger butterfly (D. genutia) were thought to be the same for more than a century until they were reclassified as separate species in 1954. And guess what: D. genutia lives in India. Hamm thinks that Rao and Murty, perhaps not knowing about the reclassification, netted bugs they assumed were monarchs but were actually common tiger butterflies. Back in the lab, they performed a technique known as a chromosome squash—squeezing the butterflies’ cells between thin films of glass until individual chromosomes are visible under a microscope—counted to 30, and published the results. Then, in 2004, Brazilian zoologist Keith Brown Jr. cited the work in his own research exploring the evolutionary history of butterflies; he never suspected that Rao and Murty might have been working with a misidentified species. Brown’s paper has been cited a dozen times since, and the idea that monarchs have 30 chromosomes is now well established in the literature. Murty has since died—though his name lives on in a namesake flatworm, Pseudodiplodiscoides murtyi—and Rao could not be located to confirm the theory. Still, it’s a plausible explanation, says Krushnamegh Kunte, a biologist at the National Centre for Biological Sciences in Bengaluru, India, who studies butterfly genetics. “Unfortunately, history has a strong influence in taxonomy,” he says. “Many Indian taxonomists continued to erroneously refer to the Indian populations of Danaus genutia as Danaus plexippus.” Hamm performed his own chromosome squash with six juvenile monarchs—real ones given to him by Kansas-based Monarch Watch, a network of scientists, teachers, and volunteers that supports research on the butterfly. Earlier this month, he reported his count of 28 chromosomes on the bioRxiv preprint server, an online repository where scientists publish work before it has been peer reviewed. Case closed, right? Not quite. A paper published a few days later on bioRxiv by some of Hamm’s former colleagues at the University of Kansas claims to have found, like Rao and Murty, 30 chromosomes in monarchs. “Previously, an observation of N=30 chromosomes was reported only for males (Nageswara-Rao and Murty 1975),” the authors write. “Our current analysis confirms the same chromosome number not only in males but also in females.” The authors of that paper declined to comment on Hamm’s findings. Hamm doubts that he miscounted the chromosomes in six different samples, but he says there’s a chance he and his former colleagues are both right. Lepidoptera genetics is notorious for the fact that chromosome counts can vary between populations of the same species and occasionally even within cells from the same individual, he explains. “I am glad that other researchers are skeptical and want to build on my minor contribution,” Hamm says. “There could be some interesting biology going on.” Kunte admits it won’t exactly shake up the field of monarch research to revise the species’s chromosome count; a few genetic studies might need to be reconsidered. The larger point is that it’s important to correct the historical record, says Akito Kawahara, a butterfly researcher at the Florida Museum of Natural History in Gainesville. The work underscores a common complaint that all too often in genetic research, taxonomists are left out of the equation, he says. As a result, genetic studies are vulnerable to species misidentifications like this one. “These kinds of things do happen with closely related species,” he says. “Twenty-eight versus 30 chromosomes doesn’t really have any impact on the conservation of the species or our understanding of it, but the next time someone makes a mistake like this, it could be with something important.”