1,676 research outputs found
Allelopathic effect of Solanum melongena L. on Vigna radiata L.
The present study has been carried out to investigate the allelopathic effect of aqueous leaf leachate of Solanum melongena L. on Vigna radiata L. The effects of leachate on germination, radicle length, plumule length, protein content and cell division in root tip meristems of seedlings of Vigna were studied. The seeds of mungbean were soaked with leaf leachate of 10, 25, 50, 75 and 100% concentrations for 4h. Bioassay indicated that there was dose-dependent inhibition of germination and seedling growth. Protein content was found to be reduced by the leachate of different concentrations as compared with control. The study also revealed that antioxidative enzymes, viz. superoxide dismutase, catalase and peroxidase activities increased with the increase in concentration of aqueous leaf leachate. Mitotic activity in root-tip cells of mungbean was found to be reduced and the impact was dose-dependent. However, chromosomal abnormalities, viz. fragment, precocious separation, sticky chromosome, disturbed metaphase and bridge were found to be increased with increasing concentrations of leachate
Wireless Multichannel Multipoint Broadcast Service for Mobile Stations
In wireless Multicast Broadcast Service (MBS), the common channel is used to multicast the MBS content to the Mobile Stations (MSs) on the MBS calls within the coverage area of a Base Station (BS), which causes interference to the dedicated channels serving the traditional calls, and degrades the system capacity. The MBS zone technology is proposed in Mobile Communications Network (MCN) standards to improve system capacity and reduce the handoff delay for the wireless MBS calls. In the MBS zone technology, a group of BSs form an MBS zone, where the macro diversity is applied in the MS, the BSs synchronize to transmit the MBS content on the same common channel, interference caused by the common channel is reduced, and the MBS MSs need not perform handoff while moving between the BSs in the same MBS zone. However, when there is no MBS MS in a BS with the MBS zone technology, the transmission on the common channel wastes the bandwidth of the BS. It is an important issue to determine the condition for the MBS Controller (MBSC) to enable the MBS zone technology by considering the Quality of Services (QoS) for traditional calls and MBS calls are used to reduce the dependency over the common channel and also it is going to reduce the delay over the network. By enabling Dynamic Channel Allocation (DCA) and Enhance Dynamic Channel Allocation (EDCA) we are going to overcome these problems
Increasing the Accuracy of Cooperative Localization by Controlling the Sensor Graph
We characterize the accuracy of a cooperative localization algorithm based on Kalman Filtering, as expressed by the trace of the covariance matrix, in terms of the algebraic graph theoretic properties of the sensing graph. In particular, we discover a weighted Laplacian in the expression that yields the constant, steady state value of the covariance matrix. We show how one can reduce the localization uncertainty by manipulating the eigenvalues of the weighted Laplacian. We thus provide insight to recent optimization results which indicate that increased connectivity implies higher accuracy and we offer an analysis method that could lead to more efficient ways of achieving the desired accuracy by controlling the sensing network
STUDY ON FRICTION STIR WELDING OF ALUMINIUM PLATES USING AN ARTIFICIAL NEURAL NETWORK
For attaching solid materials, friction stir welding (FSW) is a relatively novelmethod recently developed. Compared to fusion welding processes, it has many benefits,such as reduced distortion, porosity, shrinkage, and cracking. FSW was first used to linkaluminum alloys with limited weldability, but it has since been used to join other metallicalloys and other dissimilar alloys. It is possible to fuse two plates using FSW by inserting anon-consumable rotating tool with a specifically designed pin between them and moving italong the welding line. Multiple applications in the aerospace and shipbuilding industries andthe automobile sector have seen success with this approach owing to its many benefits.Computer-aided artificial neural network (ANN) modelling may be used in material scienceand engineering to improve the FSW process. In the same manner, as the brain processesinformation, ANN is a computer processing paradigm inspired by the brain's workings. Thereare many nerve cells in the system. ANNs, like humans, are taught by examples and maybeboth a teaching and a forecasting tool. Well-trained neural networks are excellent predictiontools and can predict results for inputs it has never seen. It may therefore be considered as anapproach to automating FSW.A wide range of variables influences the FSW process. To better understand the relationshipbetween welded material's mechanical characteristics, such as ultimate tensile strength (UTS)and hardness, this study considers three parameters: tool rotation speed, welding speed, andaxial force. An artificial neural network (ANN) is developed and then evaluated to determinethe mechanical characteristics of welded materials
Filogenetska analiza izolata pasjeg parvovirusa izdvojenih u Mathuri u Indiji.
Canine parvovirus (CPV) is an important pathogen causing acute hemorrhagic gastroenteritis in dogs and myocarditis in pups. The present study deals with an analysis of partial nucleotide sequences of the VP1/VP2 gene of CPV isolates from Mathura, India to establish their phylogenetic relationship with other CPV isolates. Out of 100 samples from dogs showing the clinical signs of gastroenteritis viz., vomiting, diarrhea and dysentery, 63 were found positive for CPV-2 by polymerase chain reaction (PCR). Among the 63 positive samples, eight samples were processed further for nucleotide sequencing. Phylogenetic analysis revealed that the CPV variants were not only closely related among themselves but also showed minimum divergence from their ancestors, such as MEV, indicating very little divergence since their origin. From the study, it may be concluded that canine parvovirus-2 variants may represent a potential threat to canine populations. Thus more efforts is required to increase epidemiological monitoring and surveillance, along with the measures necessary
to control this disease in the canine population, and to assess the efficacy of the current vaccines.Pasji parvovirus važan je uzročnik hemoragijskog gastroenteritisa u odraslih pasa i miokarditisa u štenadi. U ovom su istraživanju djelomično analizirane nukleotidne sekvencije gena VP1/VP2 izolata pasjeg parvovirusa iz Mathure u Indiji sa svrhom da se njihova filogenetska svojstva usporede s drugim izolatima toga virusa. Od 100 uzoraka izdvojenih iz pasa s gastroenteritisom odnosno s povraćanjem i proljevom, 63 su bila pozitivna na pasji parvovirus 2 upotrebom lančane reakcije polimerazom. Od toga je osam uzoraka uzeto za određivanje njihova nukleotidnog slijeda. Filogenetska analiza je pokazala da varijante pasjeg parvovirusa nisu bile samo međusobno usko srodne, već su s neznatnim skretanjem bile srodne i sa svojim predcima, kao što je virus enteritisa američke vidrice, što upućuje na njihove neznatne razlike od njihova nastanka. Može se zaključiti da varijante pasjeg parvovirusa 2 predstavljaju moguću prijetnju za populaciju pasa. Potrebno je uložiti više napora u smjeru epizootioloških istraživanja i donošenja mjera nadzora te kontrole ove zarazne bolesti zajedno s naporima za procjenu učinkovitosti postojećih cjepiva
PREDICTION OF WELD SHAPE FACTOR IN FLUX BONDED GAS TUNGSTEN ARC WELDING FOR AISI 1020 STEEL
GTAW welding has a number of drawbacks, the most significant of which is the limitedthickness of material that can be welded in a single pass, resulting in a decreased productionrate. Thus, a new welding technique Flux Bonded Gas Tungsten Arc Welding used whichlimits the drawbacks of the GTAW process. In the present work, GTAW process is carriedout on AISI 1020 carbon steel plates of 10mm thickness. The specimens were welded as beadon plate. Shape factor is calculated for FB-GTAW and compared with GTAW process. Themicrostructures and micro hardness are compared with flux and without flux at different heatinputs. The simulation of FB-GTAW process was done by NASTRAN® software. The shapefactor predicted by simulation and compared with experimental shape factor at different heatinputs. Time temperature data was measured by NASTRAN® software and compared withexperimental time temperature data. The shape factor decreases by FB-GTAW as comparedwith GTAW process. The shape factor by FB-GTAW decrease by 29.22%, 19.59% and31.13% at 120, 140 and 160 A respectively. The Micro-hardness of more than 300HV wasmeasured in FB-GTAW process. The Micro-hardness measured was about 200HV. TheMicro-hardness measured with FB-GTAW is more than normal GTAW process. This isbecause due to high cooling rate the martensite formation takes place in the weld pool by FBGTAWprocess. While with normal GTAW process acicular ferrite and pearlite are observedin the weld metal. The FB-GTAW process shows that there was maximum error of 0.395%calculated after comparing simulation and experimental shape factor. The simulation peaktemperature was 1387°C, 1300°C and 1250°C at 160 A, 140 A and 120 A respectively.Experimental results were 1350°C, 1280°C and 1235°C at above respective currents
Effect of Machining Parameters on Surface Finish and Noise Patterns for Machining EN-19 Steel with PVD-TiN Coated Mixed Ceramic Inserts in CNC Turning Operation
235-240This paper presents a relationship between the surface finish, machining conditions and the noise level generated by the turning operation for machining of EN-19 alloy steel using PVD-TiN coated mixed ceramic (Al2O3+TiCN) inserts on a CNC turning centre under wet lubrication conditions. The machining parameters considered in this study include cutting velocity, feed rate and depth of cut. The levels of machining parameters for the experimental investigation are determined using full factorial experiment model and ANOVA is applied to find the effect of machining parameters on surface roughness. Additionally, noise generated during the cutting operation for all set of experiment trials is recorded to determines the relationship between machining conditions and the surface finish
- …
