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Erosion corrosion control of 6061 aluminum alloy in multi-phase jet impingement conditions with eco-friendly green inhibitor

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Chinese Journal of Chemical Engineering 2020年第2期28卷 340-347页

作者： M.Lavanya V.ramachandra Murthy Padmalatha rao Department of Biotechnology Manipal Institute of TechnologyManipal Academy of Higher EducationManipalKarnatakaIndia Department of Chemistry Manipal Institute of TechnologyManipal Academy of Higher EducationManipalKarnatakaIndia

Erosion corrosion performance of 6061 aluminum alloy in simulated sea water slurry was investigated under multi-phase jet impingement conditions. The main objective of the work is to study erosion–corrosion of a material with engineering application and mitigate it using eco-friendly green inhibitor. Experiments were performed with the sand concentration of 0.3% and 0.3 μm size. The effect of temperature and flow rate on the performance of inhibitor was explored. Electrochemical methods were adopted for erosion-corrosion measurements. Experiments revealed that starch could mitigate erosion-corrosion with a maximum reduction efficiency of 58% at temperature of 303 K and flow rate of 4 L·min–1. Inhibition efficiency decreased with increase in flowrate and temperature. EIS spectrum demonstrated that the corrosion process in the presence on inhibitor was both charge transfer and mass transfer controlled. A key role of hydrodynamics in the performance of corrosion inhibitor was confirmed by the present study.

关键词： Erosion-corrosion Green-inhibitor Electrochemical studies Aluminum alloy Simulated sea water

Efficacy of Bluetooth-Based Data Collection for Road Traffic Analysis and Visualization Using Big Data Analytics

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Big Data Mining and Analytics 2023年第2期6卷 139-153页

作者： Ashish Rajeshwar Kulkarni Narendra Kumar K.ramachandra rao Department of Electrical Engineering Delhi Technological UniversityDelhi 110042India Department of Civil Engineering Indian Institute of Technology DelhiDelhi 110016India

Effective management of daily road traffic is a huge challenge for traffic *** traffic management has come a long way from manual control to artificial intelligence *** real-time adaptive traffic control is an unfulfilled dream due to lack of low cost and easy to install traffic sensor with real-time communication *** increasing number of on-board Bluetooth devices in new generation automobiles,these devices can act as sensors to convey the traffic information *** paper presents the efficacy of road-side Bluetooth scanners for traffic data collection and big-data analytics to process the collected data to extract traffic *** information and analysis are presented through visualizations and *** data analytics and visualizations are carried out off-line in R Studio *** aspects of the collected and processed data are also *** speed of traffic in one direction owing to the geometry of the road is also established through data *** penetration of smart phones and fitness bands in day to day use is also established through the device type of the data *** results of this work can be used for regular data collection compared to the traditional road surveys carried out annually or *** is also found that compared to previous studies published in the literature,the device penetration rate and sample size found in this study are quite high and very *** is a novel work in literature,which would be quite useful for effective road traffic management in future.

关键词： Bluetooth scanners big data visualization speed sensors

Speed–density functional relationship for heterogeneous traffic data: a statistical and theoretical investigation

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Journal of Modern Transportation 2019年第1期27卷 61-74页

作者： Hari Krishna Gaddam K.ramachandra rao Department of Civil Engineering Indian Institute of Technology

This study is an attempt to establish a suitable speed–density functional relationship for heterogeneous traffic on urban arterials. The model must reproduce the traffic behaviour on traffic stream and satisfy all static and dynamic properties of speed–flow–density relationships. As a first attempt for Indian traffic condition, two behavioural parameters, namely the kinematic wave speed at jam(Cj) and a proposed saturation flow(k), are estimated using empirical observations. The parameter Cjis estimated by developing a relationship between driver reaction time and vehicle position in the queue at the signalised intersection. Functional parameters are estimated using Levenberg–Marquardt algorithm implemented in the R statistical *** measures such as root mean squared error, average relative error and cumulative residual plots are used for assessing models fitness. We set out several static and dynamic properties of the flow–speed–density relationships to evaluate the models, and these properties equally hold good for both homogenous and heterogeneous traffic *** the numerical analysis, it is found that very few models replicate empirical speed–density data traffic ***, none of the existing functional forms satisfy all the properties. To overcome the shortcomings, we proposed two new speed–density functional forms. The uniqueness of these models is that they satisfy both numerical accuracy and the properties of fundamental diagram. These new forms would certainly improve the modelling accuracy, especially in dynamic traffic studies when coupling with dynamic speed equations.

关键词： Heterogeneous traffic Speed-density model Kinematic wave speed Traffic flow CURE plots

Modelling vehicular interactions for heterogeneous traffic flow using cellular automata with position preference

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Journal of Modern Transportation 2017年第3期25卷 163-177页

作者： Gaurav Pandey K.ramachandra rao Dinesh Mohan Department of Civil Engineering and Transportation Research and Injury Prevention Programme Indian Institute of Technology Delhi Shiv Nadar University

This paper proposes and validates a modified cellular automata model for determining interaction rate （i.e. number of car-following/overtaking instances） using traffic flow data measured in the field. The proposed model considers lateral position preference by each vehicle type and introduces a position preference parameter fl in the model which facilitates gradual drifting towards preferred position on road, even if the gap in front is sufficient. Additionally, the model also improves upon the conven- tional model by calculating safe front and back gap dynamically based on speed and deceleration properties of leader and follower vehicles. Sensitivity analysis was carried out to determine the effect of β on vehicular interac- tions and the model was calibrated and validated using interaction rates observed in the field. Paired tests were conducted to determine the determining interaction rates validity of the model in Results of the simulations show that there is a parabolic relationship between area occupancy and interaction rate of different vehicle types. The model performed satisfactorily as the simulated interaction rate between different vehicle types were found to be statistically similar to those observed in field. Also, as expected, the interaction rate between light motor vehicles （LMVs） and heavy motor vehicles （HMVs） were found to be higher than that between LMVs and three wheelers because LMVs and HMVs share the same lane. This could not be done using conventional CA models as lateral movement rules were dictated by only speeds and gaps. So, in conventional models, the vehicles would end up in positions which are not realistic. The position preference parameter introduced in this model motivates vehicles to stay in their preferred positions. This study demonstrates the use of interaction rate as a measure to validate micro- scopic traffic flow models.

关键词： Cellular automata Vehicular interaction ratePosition preference Traffic flow modelling Video-graphic survey

Comparative evaluation of roundabout capacities under heterogeneous traffic conditions

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Journal of Modern Transportation 2015年第4期23卷 310-324页

作者： Ramu Arroju Hari Krishna Gaddam Lakshmi Devi Vanumu K.ramachandra rao Department of Civil Engineering IIT Delhi Department of Civil Engineering and Transportation Research and Injury Prevention Programme (TRIPP) IIT Delhi

In heterogeneous traffic conditions, roundabout capacity is described by vehicle and driver characteristics which are different from traffic conditions in homogeneous conditions. In the present study, the capacity of the roundabout is determined using various capacity formulas such as gap acceptance models given by Highway Capacity Manual 2010 （US）, German model （2001）; empirical regression models given by TRRL （UK） and weaving models given by IRC： 65-1976 （India）. In addition, microscopic simulation model like VISSIM （PTV Ger- many） is also used to derive capacity values. Unlike the other capacity estimation models, VISSIM is helpful in estimating capacity values using geometric and driver characteristics and it can also simulate heterogeneous traffic condition accurately. Capacity is estimated after calibrating the simulation model （VISSIM） developed for the roundabout. This is achieved by incorporating different vehicle classes to represent the heterogeneous traffic environment, driver gap acceptance, and lane changeparameters. All the required inputs were extracted from the video using semi-automatic data collection methods. Data are used for the estimation of capacity values from dif- ferent methods mentioned above and for the calibration and validation of simulation model. The capacity values esti- mated form various formulas except German model are distinctly different from the field values and they are either overestimating or underestimating. Analysis of these observations reveals that the capacity values from VISSIM and German models are nearly matching with the field capacity.

关键词： Roundabout Capacity VISSIM Simulation Heterogeneous

Effect of bisphenol A and co-administration of bisphenol Aand vitamin C on epididymis of adult rats:A histological and biochemical study

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Asian Journal of Andrology 2003年第3期5卷 203-208页

作者： K.C.Chitra K.ramachandra rao P.P.Mathur School of Life Sciences Pondicherry University Pondicherry 605 014 IndiaDepartment of Anatomy Jawaharlal Institute of Postgraduate Medical Education and Research Pondicherry 605 006 IndiaSchool of Life Sciences Pondicherry University Pondicherry 605014 India

Aim: To study the effect of bisphenol A on the epididymis and epididymal sperm of rats and the possible amelioration action of co-administration with vitamin C. Methods: Male Wistar rats were orally administered bisphenol A (0.2 μg·kg-1·day-1, 2 μg·kg-1·day-1 and 20 μg·kg-1·day-1) and 0.2 μg, 2μg and 20 μg bisphenol A + 40 mg vitamin C·kg-1·day-1 for 60 days. On day 61, rats were killed with anesthetic ether and sperm collected from epididymis were used for assessment of sperm count, motility and viability and biochemical studies. A 1 % homogenate of epididymis was prepared and used for biochemical estimations. Caput, corpus and cauda epididymis were fixed in Bouin's fixative for histological studies. Results: Administration of bisphenol A caused a reduction in the epididymal sperm motility and count and the sperm viability remained unchanged. The activities of superoxide dismutase and glu-tathione peroxidase decreased, while the levels of lipid peroxidation increased in epididymal sperm and epididymis at all doses. Co-administration with vitamin C reversed the effect of bisphenol A-induced oxidative stress in epididymal sperm and epididymis. A complete degeneration of epididymal epithelium in caput, corpus and cauda regions with reduction in the number of sperms were observed at all doses of bisphenol A-treated rats. Conclusion: Bisphenol A induced oxidative stress in epididymis and caused degeneration of the epididymal epithelium of rats. Co-administration with vitamin C had a protective effect against the bisphenol A-induced toxicity in epididymal sperm and epididymis.

关键词： bisphenol A epididymis spermatozoa ascorbic acid antioxidant enzymes lipid peroxidation reactive oxygen species oxidative stress

Enhancement of luminescence intensity and spectroscopic analysis of Eu^(3+) activated and Li^+ charge-compensated Bi_2O_3 nanophosphors for solid-state lighting

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Journal of Rare Earths 2019年第4期37卷 356-364页

作者： S.Ashwini S.C.Prashantha ramachandra Naik H.Nagabhushana Department of Physics Channabasaveshwara Institute of Technology Research Center Department of Science East West Institute of Technology Department of Physics New Horizon College of Engineering CNR rao Center for Advanced Materials Tumkur University

The present work reports the synthesis, characterization, photoluminescence and photocatalytic activity of Eu^(3+)(1 mol%-11 mol%) doped and Li^+(0.5 mol%-5 mol%) co-doped Bi_2 O_3 nanophosphors(NPs) by sonochemical method. The average particle size was estimated using powder X-ray diffraction(PXRD)and transmission electron microscopy(TEM) and is found to be in the range of 30-35 nm. The scanning electron microscopy(SEM) images were highly dependent on sonication time and concentration of epigallocatechin gallate(EGCG) bio-surfactant. The energy gap of doped and co-doped Bi_2 O_3 nanophosphors was estimated using Kubelka-Munk(K-M) function and is found to be in the range of2.9-3.08 eV. The effect of Li+ co-doping on luminescence of optimized Bi_2 O_3:Eu^(3+) was studied and is found about more than 3 fold enhancement of emission intensity. Judd-Ofelt parameters(Ω_2, Ω_4 and Ω_6).transition probabilities(A_T), quantum efficiency(η), luminescence lifetime(τ_(rad)), color chromaticity coordinates(CIE) and correlated color temperature(CCT) values were estimated from the emission spectra and are discussed in detail. The estimated CIE chromaticity co-ordinates are very close to the NTSC(National Television Standard Committee) standard value of red emission. The synthesized NPs show excellent photocatalytic activity of acid red-88 under UV-light irradiation, which can degrade 98.1% in60 min. The decreasing electron-hole pair recombination rate with quick electron transfer ability is predominantly ascribed to the balance between crystallite size, morphology, band gap, defects, surface area, etc. These results show a light for the use of sonochemical route of Bi_2 O_3:Eu^(3+):Li^+ in solid state display and photocatalytic applications.

关键词： Bi2O3:Eu3+:Li+ Sonochemical Photoluminescence CIE n CCT Photocatalysis Rare earths

Human butyrylcholinesterase knock-out equivalent: Potential to assess role in Alzheimer’s disease

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Advances in Alzheimer's Disease 2012年第1期1卷 1-11页

作者： Gumpeny ramachandra Sridhar Talluri Sekhar Padmanabhuni Venkata Nageswara rao Allam Appa rao C. R. rao Advanced Institute for Mathematics Statistics & Computer Science (AIMSCS) Hyderabad India Department of Biotechnology GITAM University Visakhapatnam India Department of Computer Science GITAM University Visakhapatnam India Endocrine and Diabetes Center Visakhapatnam India

Butyrylcholinesterase (BChE) is an enzyme which has been shown to be involved in the patho-genesis, treatment and prognosis of Alzheimer’s disease. In its current form, however, evidence is equivocal with all of the associations. Variant forms of the protein exist, where the enzymatic function is lost to varying degrees. We performed in silico evaluation of these variants. Bioinformatics and molecular modeling, based on data from ESTHER database and Protein Data Bank (RCSB), were used for in silico predictions of the structures of the silent variants that involve a single amino acid change. Variants with loss of enzyme activity were evaluated for structural changes near the active site and the thermody-namic stability of the variants was estimated. The results indicated that the loss of activity of the variants can, in most cases, be attributed to structural changes in the active site or to lower thermodynamic stability. Our results showed that the loss of enzyme activity may be due to changes in the active site, oligomerization or loss of structural stability. Individuals with loss of function mutation of BChE can be studied and followed up for their proneness or resistance to cognitive decline with aging.

关键词： Apnea Anesthesia Insulin Resistance Mutants Thermal Stability

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碘酸盐催化波极谱测定微量铀(Ⅵ)

世界核地质科学 1986年第4期 74-75页

作者： R.ramachandra Murthy V.Suryanarayana rao 魏澎

因为在滴汞电极上铀的行为复杂,极谱测定铀是困难的。根据实验条件,如pH值,金属离子和支持电解质浓度,离子显出两个或三个波。研究了一个灵敏、简单、快速测定微量铀的极谱方法,原理是在滴汞电极上,借助于金属离子催化还原碘酸盐,并提... 详细信息

因为在滴汞电极上铀的行为复杂,极谱测定铀是困难的。根据实验条件,如pH值,金属离子和支持电解质浓度,离子显出两个或三个波。研究了一个灵敏、简单、快速测定微量铀的极谱方法,原理是在滴汞电极上,借助于金属离子催化还原碘酸盐,并提出分析结果。

关键词：碘酸盐离子碘化合物峰电流饱和甘汞电极催化波