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Co-Authors
- T. Sreenivasa Rao
- S. Rajagopalan Nair
- A. T. Rao
- S. Srinivas
- At. Rao
- Y. Srinivasa Rao
- Shaik Nazeer
- Syed Ziaur Rahman
- G. Padmavathi
- K. V. V. S. Reddy
- Shaik Jakeer Husain
- K. Kiran Kumar
- P. Srinivasa Rao
- D. B. Ghosh
- Chamanlal
- V. Vijayakumar
- P. Sreenivasulu
- A. Vinaya Babu
- K. Ratna Kumar
- G. Madhusudhan Reddy
- V. S. N. Venkata Ramana
- K. Ratnakumar
- M. V. S. N. Maheswar
- G. R. K. Prasad
- Kara Alekhya
- K. Raghava Rao
- P. Vijaya Kumar
- V.S.N. Venkata Ramana
- K. Prasad Rao
Journals
- NITTE Management Review
- Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)
- Networking and Communication Engineering
- Fuzzy Systems
- Data Mining and Knowledge Engineering
- Indian Journal of Science and Technology
- Indian Welding Journal
- Oriental Journal of Computer Science and Technology
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Srinivasa Rao, K.
- Changing Dimensions of Corporate Governance in Public Sector Banks in India
Abstract Views :154 |
PDF Views:86
Authors
Affiliations
1 Staff College, Bank of Baroda, Ahmedabad, IN
1 Staff College, Bank of Baroda, Ahmedabad, IN
Source
NITTE Management Review, Vol 2, No 2 (2008), Pagination: 52-61Abstract
No Abstract.Full Text
- Stratigraphy of the Upper Precambrian Albaka Belt, East of the Godavari River in Andhra Pradesh and Madhya Pradesh
Abstract Views :196 |
PDF Views:2
Authors
Affiliations
1 6-3-628/8/1, Ravindra Nagar, Khairatabad, Hyderabad 500004, IN
2 Barkatpura, Hyderabad, IN
3 Ananda Nagar, Khairatabad, Hyderabad 500004, IN
1 6-3-628/8/1, Ravindra Nagar, Khairatabad, Hyderabad 500004, IN
2 Barkatpura, Hyderabad, IN
3 Ananda Nagar, Khairatabad, Hyderabad 500004, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 20, No 5 (1979), Pagination: 205-213Abstract
The lithostratigraphic succession worked out for the Upper Precambrian of Venkatapuram-Cherla area includes Cherla Formation, Somandevara Quartzite, Tippapuram Shale Utlapalli Conglomerate, Albaka Sandstone, Nambi Breccia and Doli and Usur Sandstones. Three disconformities, one each at the base of the Somandevara Quartzite, Utlapalli Conglomerate and the Nambi Breccia, have been inferred. Of these, the one at the base of the Nambi is believed to be the most significant one. Based on gross lithological similarity and relative stratigraphic position, the different Upper Precambrian units of this area are correlated with those of the already established Pakhal and Sullavai Groups of the main Upper Precambrian belt, west of the Godavari River. The correlation implies that the nature of the contact between the Pakhal and Sullavai Groups of the, main Upper Precambrian belt on the western side of the Godavari, a much debated question, is a profound unconformity.
- Petrology of Basic Granulites from Maruturu Near Anakapalle in the Eastern Ghats Granulite Belt
Abstract Views :192 |
PDF Views:2
Authors
Affiliations
1 Department of Geology, Andhra University, Visakhapatnam - 530 003, IN
1 Department of Geology, Andhra University, Visakhapatnam - 530 003, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 54, No 3 (1999), Pagination: 279-289Abstract
Basic granulites frequently occur in garnetiferous quartzo-feldspathic gneisses and rarely in garnetiferous sillimanite gneisses, calc-silicate rocks and quartzites in the entire Eastern Ghats Granulite Belt (EGGB). Commonly these basic layers are parallel to the foliation and are occasionally boudinaged. These share a common tectonic and metamorphic history with those of the associated litho-units. There are also unusual basic granulite dykes which crosscut the foliation in quartzo-feldspathic gneisses, folded calc-silicate rocks and basic granulites at Maruturu near Anakapalle in the EGGB. The two generations of basic granulites are even grained with a polygonal annealed mosaic and characterised by the mineral assemblage: coexisting pyroxenes and plagioclase. The mineral composition data of coexisting pyroxenes indicate large scale equilibrium at granulite facies conditions. Both types of basic granulites have almost similar bulk composition and have tholeiitic affinity. The basic granulite dykes have low contents of REE with a smooth distribution pattern and a general decrease from LREE to HREE. The revival of basic magmatism during post D1 and D2 at Maruturu reveals that extensional set-up recurs in the EGGB. The basic granulites of Maruturu are correlated with Proterozoic metabasic dykes in East Antarctica and Western Australia. The 1300 Ma basic granulites reported in Maruturu and Rayagada in the vicinity of Maruturu indicate that these intrusive basic bodies are coeval with the dyking events in Eastern Albany Mobile Belt in Western Australia and Vestfold Hill Block in Prydz Bay region in East Anatarctica.Keywords
Petrology, Geochemistry, Basic Granulite, Mineral Compositions, Eastern Ghats Granulite Belt, Andhra Pradesh.- Pyroxene Exsolution Textures in Plutonic Basic Igneous Rocks from Kandra Igneous Complex, Nellore Schist Belt, Andhra Pradesh
Abstract Views :198 |
PDF Views:135
Authors
Affiliations
1 Department of Geology, Andhra University, Visakhapatnam - 530 003, IN
1 Department of Geology, Andhra University, Visakhapatnam - 530 003, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 63, No 3 (2004), Pagination: 337-340Abstract
No Abstract.Full Text
- Raw Era in Cloud Computing
Abstract Views :201 |
PDF Views:7
Authors
Affiliations
1 Department of Information Technology, Bapatla Engineering College, Bapatla, Andhra Pradesh, IN
2 Department of Computer Science & Engineering, Bapatla Engineering College, Bapatla, AndhraPradesh, IN
3 Department of Information Technology, College of Applied Sciences, Ibri, OM
1 Department of Information Technology, Bapatla Engineering College, Bapatla, Andhra Pradesh, IN
2 Department of Computer Science & Engineering, Bapatla Engineering College, Bapatla, AndhraPradesh, IN
3 Department of Information Technology, College of Applied Sciences, Ibri, OM
Source
Networking and Communication Engineering, Vol 3, No 13 (2011), Pagination: 833-836Abstract
Cloud computing is using the internet to access someone else's software running on someone else's hardware in someone else's data center. This paper explores the architecture of cloud computing and presents a new technology in which cloud computing has a software in the form of bloom. Bloom is a programming language which has received a great deal of attention following its implementation in Hadoop. Hadoop is a platform for this language. Apache Hadoop is a software framework (platform) that enables a distributed manipulation of vast amount of data. This paper also describe the architecture Hadoop and various scheduling follows by it.Keywords
Cloud Computing, Architecture, Bloom, Hadoop, Scheduling.- Performance Evaluation of Parallel and Series Communication Network with Dynamic Bandwidth Allocation
Abstract Views :166 |
PDF Views:2
Authors
Affiliations
1 Department of Technical Education, AP, IN
2 Department of Statistics, Andhra University, Visakhapatnam, IN
3 Electronics and Communication Engineering, Andhra University, Visakhapatnam, IN
1 Department of Technical Education, AP, IN
2 Department of Statistics, Andhra University, Visakhapatnam, IN
3 Electronics and Communication Engineering, Andhra University, Visakhapatnam, IN
Source
Networking and Communication Engineering, Vol 1, No 7 (2009), Pagination: 410-421Abstract
In this paper a parallel and series communication network model with dynamic bandwidth allocation is developed and analyzed. In order to reduce congestion in buffer and to improve voice quality several congestion control methods like bit dropping,selective packet discarding, flow control etc., are developed and successfully implemented. to have an efficient utilization we propose dynamic allocation of bandwidth i.e. the transmission rate of the data/voice packet dependent on the content of the buffer just before it get transmitted. The end to-end performance of the model is measured by approximating the arrival and service processes of the packets follow poisson process. The transient analysis of the communication network shows that dynamic allocation has a significant effect in reducing mean delays and improving throughput of the transmitter. Graphs illustrate performance of the network model for different parameters.
Keywords
Dynamic Bandwidth Allocation, Joint Probability Generating Function, Mean Delay, Poisson Process, Throughput.- Application of Fuzzy Logic for Epileptic Seizure Detection
Abstract Views :159 |
PDF Views:1
Authors
Affiliations
1 Department of Electronics and Communication Engineering, Vignan Institute of Technology and Science, Deshmukhi-508284, Nalgonda Dist, A.P., IN
2 Anurag Group of Institutions, Hyderabad, IN
1 Department of Electronics and Communication Engineering, Vignan Institute of Technology and Science, Deshmukhi-508284, Nalgonda Dist, A.P., IN
2 Anurag Group of Institutions, Hyderabad, IN
Source
Fuzzy Systems, Vol 4, No 5 (2012), Pagination: 166-170Abstract
In this work fuzzy logic approach was presented for epileptic seizure detection. The EEG signal is decomposed into five sub bands using discrete wavelet transforms. Energy, Covariance, Inter quartile Range (IQR), and Median absolute deviation (MAD) features were extracted from each sub band and considered as the inputs for a fuzzy system Fuzzy rules were derived based on expert's knowledge and reasoning. For each sub band fuzzy system is applied the fuzzy output is combined from each sub band and threshold technique is applied to discriminate normal and epileptic. The overall classification accuracy of 97% was achieved.Keywords
Electroencephalogram (EEG) Epileptic Seizures, Discrete Wavelet Transform (DWT).- An Efficient K-Means Clustering Algorithm for Large Data
Abstract Views :193 |
PDF Views:4
Authors
Affiliations
1 Department of Information Technology, Bapatla Engineering College, Bapatla, Andhra Pradesh, IN
1 Department of Information Technology, Bapatla Engineering College, Bapatla, Andhra Pradesh, IN
Source
Data Mining and Knowledge Engineering, Vol 3, No 9 (2011), Pagination: 539-543Abstract
Cluster analysis is one of the major data analysis methods for clustering the large data sets. The cluster analysis deals with the problems of organization of a collection of data objects into clusters based on some similarity. K-means is one of the most popular data partitioning algorithms that solve the well known clustering problem. Performance of the k-means clustering greatly depends upon the correctness of the initial centroids. Typically the initial centroids for the original k-means clustering are determined randomly. So, the clustering result may reach the local optimal solutions, not the global optimum. Several improvements have been proposed to improve the performance of k-means algorithm. This paper proposes an Efficient k-means algorithm for finding the better initial centroids and an efficient way for assigning data points to appropriate clusters. The proposed algorithm is tested with six bench mark datasets, which are taken from UCI machine learning data repository and found that the proposed algorithm gives better result than the existing.Keywords
Clustering, Data Partitioning, Data Mining, Heuristic K-Means, K-Means Algorithm.- Diagenesis of the Dark Grey Limestone of Nagod Formation, Madhya Pradesh
Abstract Views :183 |
PDF Views:2
Authors
Affiliations
1 6-3-609/195, Ananda Nagar, Khairatabad, Hyderabad, IN
2 Professors Colony, Bhopal (M.P.), IN
1 6-3-609/195, Ananda Nagar, Khairatabad, Hyderabad, IN
2 Professors Colony, Bhopal (M.P.), IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 17, No 4 (1976), Pagination: 490-502Abstract
The rocks of the Vindhyan supergroup show evidences of deposition in a shallow marine environment, the depositional basin being similar to 'epeiric sea'. The dark grey limestone unit of the Nagod Limestone Formation is a low magnesian limestone and is invariably an intrasparite or oosparite with variable amounts of authigenic cement spar, neomorphic spar and micrite occupying intra- and inter-allochemical pore spaces. Fibrous nonferroan calcite, dog tooth fringe of nonferroan calcite, drusy mosaic of ferroan calcite and syntaxial rim cement, constitute the different types of cements noticed. Authigenic minerals like dolomite, quartz, plagioclase and pyrite are present in small quantities. Based on the precipitational and recrystallisation fabrics of the calcite and the presence of different authigenic minerals, the diagenetic history of the limestone is worked out.- Basic Volcanism along K-T Boundary from Rajahmundry, East Coast of India
Abstract Views :176 |
PDF Views:154
Authors
Affiliations
1 Department of Geology, Andhra University, Visakhapatnam - 530 003, IN
1 Department of Geology, Andhra University, Visakhapatnam - 530 003, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 60, No 5 (2002), Pagination: 583-586Abstract
Basalts near Kateru, north of Rajahmundry in the East Godavari district and near Pangidi in the West Godavari district of Andhra Pradesh along the East Coast of India are of particular interest to investigators on account of their separation from the well known West Coast Deccan Basalts, localised around Bombay. The basalts around Rajahmundry are tholeiitic with equigranular, subophitic to ophitic textures. The principal constituents are plagioclase (An55-56) and brownish nonpleochroic augite. The REE patterns of Rajahmundry basalts have a marked increased enrichment in LREE due to crustal contamination. The K-Ar age of Kateru basalts is 75.1±4.9Ma. The reported biochronostratigraphy of microfauna in the sediments closely associated in time and space with basalt flows in the Krishna-Godavari basin, east of Rajahmundry indicate that the age of basic volcanism is around 67 Ma. The lower limit of 70 Ma for the Kateru basalts supports that these basalts have evolved along with West Coast Deccan Basalts (69-65 Ma), where, the intensity of basic magmatism is more. The geological setting of Rajahmundry basalts with coastal sedimentary rocks indicate that the basic magmatism and sedimentation had taken place during the Cretaceous-Tertiary boundary.Full Text
- Optimizing Power in Sequential Circuits by Reducing Leakage Current using Enhanced Multi Threshold CMOS
Abstract Views :155 |
PDF Views:0
Authors
Affiliations
1 Department of ECE, JNTUK, Kakinada – 533003, Andhra Pradesh, IN
2 ECE, T.R.R College of Engineering, Hyderabad - 502301,Telangana, IN
1 Department of ECE, JNTUK, Kakinada – 533003, Andhra Pradesh, IN
2 ECE, T.R.R College of Engineering, Hyderabad - 502301,Telangana, IN
Source
Indian Journal of Science and Technology, Vol 9, No 36 (2016), Pagination:Abstract
Technical thirst of man is in exponential rise and posing critical challenges in using this technology. This is much evident in the design of VLSI circuits. Sequential circuit designing demands lesser energy consumption, smartness and increased functional density. In this domain, every development in the recent past has energy as the focal point. MTCMOS exactly serves the purpose of reduced power consumption in digital circuits. This technique provides lower leakage current and offers enhanced speed. It uses low threshold voltage devices for low leakage and high threshold voltage components as sleep transistors. These sleep transistors are good enough to isolate the logic modules from the supply, ground in order to reduce the leakage current. Care is ensured particularly in the mode transition and also the least possible time for turn ON state in a circuit, as these are the primary concerns for power consumption and thereby for the performance degradation of integrated circuits. In this paper, a successful attempt was made in enhancing the advantage of employing MTCMOS technique towards lesser power consumption in sequential circuit designing.Keywords
Leakage Current and Sequential Circuit, MTCMOS, Power or Energy Consumption.Full Text
- Studies on Partially Melted Zone and Pitting Corrosion Resistance of A356 Aluminium-Silicon Alloy GTA Welds
Abstract Views :342 |
PDF Views:4
Authors
Affiliations
1 Department of Metallurgical Engineering, Government Polytechnic, Visakhapatnam-530 007, IN
2 Metal Joining Group, Defence Metallurgical Research Laboratory, Hyderabad-500 058, IN
3 Department of Metallurgical Engineering, Andhra University College of Engineering(A), Visakhapatnam-530 003, IN
1 Department of Metallurgical Engineering, Government Polytechnic, Visakhapatnam-530 007, IN
2 Metal Joining Group, Defence Metallurgical Research Laboratory, Hyderabad-500 058, IN
3 Department of Metallurgical Engineering, Andhra University College of Engineering(A), Visakhapatnam-530 003, IN
Source
Indian Welding Journal, Vol 47, No 1 (2014), Pagination: 27-42Abstract
Gas Tungsten Arc Welding (GTAW) of Pressure Die cast A356 Al-Si alloy with strontium modification was done both with and without filler. The microstructural changes in Weld metal zone (WM), Heat affected zone (HAZ) and Partially Melted Zone (PMZ) were studied. PMZ of aluminium alloy weld is an important region, as it is the weak link in the weldments. It is significantly affected by the welding parameters, filler metal and prior thermal condition. In the present work affect of welding techniques i.e. Continuous Current Gas Tungsten Arc Welding (CCGTAW) and pulsed Current Gas Tungsten Arc Welding (PCGTAW) on microstructure and pitting corrosion resistance of weld metal, Partially melted zone and Heat affected zone in the prior conditions of as cast and T6 conditions were studied. Susceptibility to liquation was found to be less in the weld made in as cast condition of pulsed current GTA welds compared to that of artificially aged condition (T6) of continuous current GTA welds. This was mainly attributed to the silicon enrichment of eutectics at the grain boundaries. Potentiodynamic polarization testing was carried out to study the pitting corrosion behavior of the welds. Pitting corrosion resistance of weld made with pulsed current GTAW of as cast alloy is better than the that of weld made with continuous current GTAW of T6 alloy. This is mainly attributed to the discontinuous eutectic formation at the grain boundary base metal and PMZ.Keywords
Aluminium Alloys, GTA Welds, Partially Melted Zone, Continuous Current Gas Tungsten Arc Welding, Pulsed Current Gas Tungsten Arc Welding.- Effect of Welding Process on Microstructure and Pitting Corrosion Behavior of AA2014 Al-Cu Alloy Welds
Abstract Views :385 |
PDF Views:4
Authors
Affiliations
1 Department of Mechanical Engineering, GITAM Institute of Technology, GITAM University, Visakhapatnam - 530045, IN
2 Department of Metallurgical Engineering, Government Polytechnic, Visakhapatnam - 530 007, IN
3 Metal Joining Group, Defence Metallurgical Research Laboratory, Hyderabad - 500 058, IN
4 Department of Metallurgical Engineering, Andhra University College of Engineering (A), Visakhapatnam- 530 003, IN
1 Department of Mechanical Engineering, GITAM Institute of Technology, GITAM University, Visakhapatnam - 530045, IN
2 Department of Metallurgical Engineering, Government Polytechnic, Visakhapatnam - 530 007, IN
3 Metal Joining Group, Defence Metallurgical Research Laboratory, Hyderabad - 500 058, IN
4 Department of Metallurgical Engineering, Andhra University College of Engineering (A), Visakhapatnam- 530 003, IN
Source
Indian Welding Journal, Vol 45, No 3 (2012), Pagination: 29-40Abstract
Wrought AA 2014 Al-Cu alloy in mill annealed (O) condition and naturally aged (T4) condition was welded by the Gas Tungsten Arc Welding (GTAW) and Friction Stir Welding (FSW) processes. The microstructural changes and pitting corrosion behaviour in all zones of welds for both the welding processes have been investigated when the alloy was welded in O as well as in T4 conditions. It was observed that naturally aged (T4) alloy weld exhibited better corrosion properties than annealed (O) alloy weld this is attributed to the precipitation of fine grained eutectics in T4 alloy during welding. The pitting corrosion resistance was found to be better and uniform through out cross section of the friction stir welds compared to GTA welds, indicating improvement in corrosion properties of the welds in solid state welding.Keywords
Gas Tungsten Arc Welding, Friction Stir Welding, AA2014 Alloy, Partially Melted Zone, Thermomechanically Affected Zone, Pitting Corrosion, Potentiodynamic Polarization.- Corrosion Resistance of Friction Stir Welded AA6061 Aluminium Alloy
Abstract Views :362 |
PDF Views:4
Authors
Affiliations
1 Department of Metallurgical Engineering, Government Polytechnic, Visakhapatnam, IN
2 Defence Metallurgical Research Laboratory, Hyderabad, IN
3 Department of Metallurgical Engineering, Andhra University College of Engineering (A), Visakhapatnam-530 003, IN
1 Department of Metallurgical Engineering, Government Polytechnic, Visakhapatnam, IN
2 Defence Metallurgical Research Laboratory, Hyderabad, IN
3 Department of Metallurgical Engineering, Andhra University College of Engineering (A), Visakhapatnam-530 003, IN
Source
Indian Welding Journal, Vol 45, No 3 (2012), Pagination: 41-53Abstract
Present work pertains to microstructure and the corrosion behaviour of the nugget zone (NZ), thermo mechanically affected zone (TMAZ) and heat affected zone (HAZ) of friction stir welded AA6061 alloy. An attempt was made to find the influence of prior thermal temper of the alloy. Potentio-dynamic polarisation testing was used to determine the pitting corrosion resistance of the welds. Optical microscopy (OM) and transmission electron microscopy (TEM) with Energy dispersive X-ray spectroscopy studies were carried out to find the mechanism of formation of TMAZ and corrosion. Friction stir welding of this alloy resulted in fine recrystallized grains in weld nugget which has been attributed to frictional heating and plastic flow. The process also produced a softened region in the weld nugget, which may be due to the dissolution and growth of possible precipitates. Corrosion resistance of nugget zone has been found to be higher than that of TMAZ and base metal. Corrosion resistance of naturally aged (T4) alloy exhibit higher corrosion resistance than that of artificial aged (T6) alloy.Keywords
Pitting Corrosion, General Corrosion, Dynamic Polarisation, Friction Stir Welding, Aluminium Alloys.- An Incentive-Based Peer-to-Peer Grid Scheduling
Abstract Views :159 |
PDF Views:6
Authors
Affiliations
1 Department of Computer Science, Bhimavaram Institute of Engineering & Technology, Bhimavaram, Affiliate To JNTUK, Kakinada - 534 243, IN
2 CSE Department PVPSIT, Vijayawada, Affiliate To JNTU, Krishna (District) A.P. - 520 00, IN
1 Department of Computer Science, Bhimavaram Institute of Engineering & Technology, Bhimavaram, Affiliate To JNTUK, Kakinada - 534 243, IN
2 CSE Department PVPSIT, Vijayawada, Affiliate To JNTU, Krishna (District) A.P. - 520 00, IN
Source
Oriental Journal of Computer Science and Technology, Vol 4, No 2 (2011), Pagination: 305-315Abstract
In a grid commuting environment, resources are autonomous, wide-area distributed, and they are usually not free. These unique characteristics make scheduling in a self-sustainable and market-lime grid highly challenging. The goal of our work is to build such a global computational grid that every participant has enough incentive to stay and play in it. There are two parties in the grid: resources consumers and resource providers. Thus the performance objective of scheduling is two-fold: for consumers, high successful execution rate of jobs, and for providers, fair allocation of benefits. We propose an incentive-based grid scheduling, which is composed of a P2P decentralized scheduling framework and incentive-based scheduling algorithms. We present an incentive-based scheduling scheme, which utilizes a peer-to-peer decentralized scheduling framework, a set of local heuristic algorithms, and three market instruments of job announcement, price, and competition degree. The results show that our approach outperforms other scheduling schemes in optimizing incentives for both consumers and providers, leading to highly successful job execution and fair profit allocation.Keywords
Grid Computing, Scheduling, Peer to Peer, Resource Consumers, Resource Providers.Full Text
- Dynamic Detection of PPG(Photo Plethysmography) Signals Using Mems Self Designed Sensors
Abstract Views :174 |
PDF Views:0
Authors
Affiliations
1 Department of ECE, KL University, Vaddeswaram, Guntur – 522502, Andhra Pradesh, IN
1 Department of ECE, KL University, Vaddeswaram, Guntur – 522502, Andhra Pradesh, IN
Source
Indian Journal of Science and Technology, Vol 10, No 15 (2017), Pagination:Abstract
Objectives: To design Micro Electro Mechanical System (MEMS) based sensor with novel design considerations to detect/ identify PhotoPlethysmography(PPG) signals when the person is in dynamic mode. To simulate the above design using COMSOL Multiphysics and evaluate the results with the existing methodologies. Methods/Statistical Analysis: A MEMS based sensor with a four T-shaped cantilever with middle load hanged structure is designed in COMSOL Multiphysics and after attaining the required resonant frequency of PPG, by using capacitive actuation technique the acquired mechanical signals are evaluated and digitised. Findings: PPG sensors optically recognize changes in tidal volume of blood (i.e., changes in the force of light perceived) in the vascular bed of little scale tissue by reflection from or transmission through the tissue. If the person is in static mode it is very easy to detect blood flow rate. If suppose the person is not in rest, i.e., may be dynamic we will observe many variations in blood flow rate. So it is very difficult to estimate the blood flow rate. This Patch type device easily measures the blood flow rate. Application/Improvements: Mainly these type of devices are useful to detect variations in blood flow rate in human whether in static condition or in dynamic condition. In future we are planning to develop implantable sensors with reporting system to doctor in particular intervals of time. This may be helpful to doctors to cater the needs of human society at right time whenever it is neededKeywords
Capacitive Actuation, Dynamic, Implantable, MEMS, PPG, Static.Full Text
- Microstructure, Mechanical and Corrosion Behaviour of AA7075 Aluminium Alloy Friction Stir Welds
Abstract Views :416 |
PDF Views:17
Authors
P. Vijaya Kumar
1,
G. Madhusudhan Reddy
2,
G. Madhusudhan Reddy
2,
K. Srinivasa Rao
3,
K. Srinivasa Rao
3
Affiliations
1 Department of Mechanical Engineering, Raghu Institute of Technology, Visakhapatnam, IN
2 Defence Metallurgical Research Laboratory, Hyderabad, IN
3 Department of Metallurgical Engineering, Andhra University, Visakhapatnam, IN
1 Department of Mechanical Engineering, Raghu Institute of Technology, Visakhapatnam, IN
2 Defence Metallurgical Research Laboratory, Hyderabad, IN
3 Department of Metallurgical Engineering, Andhra University, Visakhapatnam, IN
Source
Indian Welding Journal, Vol 51, No 2 (2018), Pagination: 66-74Abstract
Friction stir welding (FSW) is emerging as an alternative technique for joining high strength aluminium alloys as it eliminates the problems during fusion welding. In this work, the effect of post weld treatments (PWHT), viz., peak aging (T6) and retrogression and reaging (RRA) on the microstructure, mechanical properties, pitting corrosion and stress corrosion cracking (SCC) resistance of AA7075 aluminium alloy friction stir welds has been studied. An attempt also has been made to change the chemical composition of the weld nugget by adding boron carbide (B4C) nano powder with the aid of the FSW. Hardness and tensile properties were found to be better in PWHT – T6. Pitting corrosion and SCC resistances were improved in PWHT-RRA condition with negligible loss of strength when compared to PWHT-T6. RRA promotes coarse precipitation of the equilibrium phase η in the grains and sub grain boundaries, while maintaining a fine distribution of η' in the grain interiors. The increased strength and hardness in the peak aged (T6) condition was attributed to the presence of semi-coherent intermediate η' (MgZn2). With the addition of B4C nano powder to the weld nugget, hardness, tensile properties, pitting corrosion resistance and SCC resistance were further improved significantly when compared to the unreinforced weld nugget. PWHT-RRA treatment on the welds with B4C nano powder addition resulted in improved hardness of weld nugget which is attributed to the uniform distribution of strengthening precipitates in the matrix and powder strengthening. Pitting corrosion resistance, Tensile strength and SCC resistance was improved significantly in B4C added welds after RRA treatment when compared to the same welds without B4C addition.Keywords
Friction Stir Welding, FSW, AA7075 Aluminium Alloy, Pitting Corrosion, Stress Corrosion Cracking, Retrogression-Reaging, RRA, Boron Carbide (B4C).References
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- A Comparison Between Microstructure, Tensile Properties and Pitting Corrosion Resistance of Friction Stir and Gas Tungsten Arc Ferritic Stainless Steel Welds
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Authors
Affiliations
1 Defence Metallurgical Research Laboratory, Hyderabad, 500 058, IN
2 Department of Metallurgical Engineering, A. U. College of Engineering (A), Visakhapatnam - 530 003, IN
1 Defence Metallurgical Research Laboratory, Hyderabad, 500 058, IN
2 Department of Metallurgical Engineering, A. U. College of Engineering (A), Visakhapatnam - 530 003, IN
Source
Indian Welding Journal, Vol 46, No 4 (2013), Pagination: 59-64Abstract
In the present work an attempt was made to study the pitting corrosion susceptibility of AISI 430 ferritic stainless steel welds. Gas tungsten arc (GTA) welding and friction stir welding (FSW) processes were used to make welds. Potentio-dynamic polarization test was used to evaluate pitting corrosion resistance of the welds. Optical and electron microprobe analysis were used to study the microstructure and corrosion mechanism respectively. It was observed that the weld microstructure of GTA weld was predominately columnar. Friction stir weld exhibited fine equiaxed grain structure. Investigations clearly revealed that pitting corrosion resistance of friction stir weld zone was inferior compared to GTA weld in which breakdown potential was reduced by chrornium depletion. This was due to enhanced formation of intermetallic phase in friction stir welds compared to GTA welds. This was attributed to the slower cooling rate of friction stir welds, which results in longer exposure to the temperature range for precipitation during cooling cycle. Fine grain structure of friction stir weld has resulted in greater chromium depleted area than that of weld zone of GTA weld. In addition to the above, lower pitting corrosion resistance of friction stir welds was correlated to the formation of strain induced martensite in the nugget zone. Presence of residual stresses was also found to be affecting localized corrosion resistance by increasing number of active anode sites on the surface.
Keywords
Piiting Corrosion, Ferritic Stainless Steel, Welding, Microstructure, Sensitization.- Partially Melted Zone in Dissimilar Aluminium Alloy Welds-Effect of Prior Thermal Temper and Welding Process
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Authors
Affiliations
1 Department of Mechanical Engg., PVP Siddhartha Institute of Technology, Vijayawada-520007, IN
2 Defence Metallurgical Research Laboratory, Hyderabad-500 058, IN
3 Department of Metallurgical Engineering, Andhra University College of Engineering(A), Visakhapatnam - 530 003, IN
1 Department of Mechanical Engg., PVP Siddhartha Institute of Technology, Vijayawada-520007, IN
2 Defence Metallurgical Research Laboratory, Hyderabad-500 058, IN
3 Department of Metallurgical Engineering, Andhra University College of Engineering(A), Visakhapatnam - 530 003, IN
Source
Indian Welding Journal, Vol 43, No 2 (2010), Pagination: 32-40Abstract
Partially melted zone (PMZ) of aluminium alloy welds is an important region and requires careful attention. This is mainly because PMZ in these alloys is a weak link in the weldments and is significantly affected by welding parameters. Microstructural changes in PMZ are related not only to welding heat input and processes, but also depend on the initial thermal history of the alloy (for example, whether it is in O, T4, T6 orT87 condition etc.). Interestingly not many detailed studies are available in this respect. In the present work effect of prior thermal temper and welding process on the PMZ behaviour of dissimilar AA2014 and AA6061 alloy GTA and EB welds were studied. Grain coarsening and melting in PMZ is more when the alloys are welded in T4 temper than in O condition and AA2014 alloy is prone for liquation compared to AA6061 alloy which attributes high alloying element concentration in AA2014 side of the joint. EB welding proved to be efficient welding process compared to GTA welding in terms of resistance to liquation and better mechanical properties.
Keywords
Partially Melted Zone, Gas Tungsten Arc Welding, Electron Beam Welding, Dissimilar Alloy Welds.- Partially Melted Zone in Aluminium Alloy Welds
Abstract Views :252 |
PDF Views:5
Authors
Affiliations
1 Department of Metallurgical and Materials Engineering Indian Institute of Technology Madras, Chennai-600036, IN
1 Department of Metallurgical and Materials Engineering Indian Institute of Technology Madras, Chennai-600036, IN