446 research outputs found

    A New Metamaterial Printed Microstrip Yagi -Array Antenna for ISM band Applications

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    A traditional yagi antenna is used for broadband applications. A New Metamaterial Printed Microstrip Yagi -Array Antenna has been introduced here. This antenna is found to operate at 2.4GHz. The microstrip yagi-array antenna is loaded with artificial split ring resonators (SRRs) which is used for achieving the metamaterial effect in the structure. The overall circuit size of the designed antenna is 11.5*11.5*0.25mm3 with reduced cross polarization and the substrate used is FR4 epoxy with dielectric constant 4.4 which is readily available. The designed antenna achieved about 4dB of gain and it also achieved a high directional characteristic of 5-9dB in the operating band. The designed antenna had a minimum return loss of about -8dB. The achievement of narrowband width for ISM band application enhances the efficiency of the antenna at the specified band and reduces the interference level

    Seamless Heterogeneous Handoff Based on SAP

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    Contemporarily there has been a number of techniques being suggested and used for heterogeneous handoff hitch. Different types of decision making methods are being implemented for handoff impediment. Mobile terminals progressing in neighbourhood will incur a handoff when its link capacity decreases below the threshold level. Various types of Multiple Attribute Decision Making methods have been exploited for handoff decision making. Here we have used a novel Reliable Seamless Handoff such as Simple Analytical Process method which uses Analytical Hierarchy Process for predicting the criterion weights and employed Simple Additive Weighting method for handoff decision making. Alternatives such as GSM, CDMA and EDGE networks are used. Data Rate, Packet Loss, Velocity, Bandwidth, Dwell time and Jitter are the parameters applied

    Twin pregnancy with a complete hydatidiform mole and coexisting foetus

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    Coexistence of a viable foetus with a complete hydatidiform mole is a rare entity. Traditionally, termination of pregnancy was recommended because of severe maternal and foetal complications. Here we report a case of a 30 year old G2A1 at 27 weeks with a twin pregnancy with a complete hydatidiform mole and coexisting normal foetus who took home a healthy baby without any persistent trophoblastic disease. This case is presented for the rarity of occurrence and good outcome

    A comparative study of perinatal morbidity and mortality of presenting twin to its co-twin

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    AIM & OBJECTIVES: To compare the perinatal morbidity & mortality of presenting twin to its co-twin based on • Mode of delivery, • Gestational age at delivery, • Chorionicity, • Discordancy, • Birth weight. DESIGN OF STUDY: Prospective analytical study. PERIOD OF STUDY: 1 year. COLLABORATING DEPARTMENT: Department of Paediatrics. METHODOLOGY: The study is conducted on antenatal women with twin pregnancy admitted to labour ward for delivery. Patients are allotted based on inclusion and exclusion criteria. Patients are selected randomly and informed consent is obtained. CONCLUSION: Twin pregnancy is more common among women of age less than 30years in our study. There is male preponderance in both Twin I and Twin II. Multiparous women in our study are higher incident twin mothers. Study group entirely belongs to low socio-economic status. RDS is more common in Twin II,hence need for mechanical ventilation is more in Twin II compared to Twin I. SEPSIS is more common in Twin I with PROM contributing to the major cause of sepsis Thus the perinatal mortality is similar in both Twin I and Twin II but the cause is different and being SEPSIS and RDS respectively. The study helps to analyse the difference in the outcome of both the twins & to find out various factors which influence it, in the era of sonography, fetal monitors, judicious use of inducing agents, increased & prompt cesarean delivery. This will be helpful in counselling women with twin gestations in future

    Octopus arms exhibit exceptional flexibility

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Kennedy, E. B. L., Buresch, K. C., Boinapally, P., & Hanlon, R. T. Octopus arms exhibit exceptional flexibility. Scientific Reports, 10(1), (2020): 20872. doi:10.1038/s41598-020-77873-7.The octopus arm is often referred to as one of the most flexible limbs in nature, yet this assumption requires detailed inspection given that this has not been measured comprehensively for all portions of each arm. We investigated the diversity of arm deformations in Octopus bimaculoides with a frame-by-frame observational analysis of laboratory video footage in which animals were challenged with different tasks. Diverse movements in these hydrostatic arms are produced by some combination of four basic deformations: bending (orally, aborally; inward, outward), torsion (clockwise, counter-clockwise), elongation, and shortening. More than 16,500 arm deformations were observed in 120 min of video. Results showed that all eight arms were capable of all four types of deformation along their lengths and in all directions. Arms function primarily to bring the sucker-lined oral surface in contact with target surfaces. Bending was the most common deformation observed, although the proximal third of the arms performed relatively less bending and more shortening and elongation as compared with other arm regions. These findings demonstrate the exceptional flexibility of the octopus arm and provide a basis for investigating motor control of the entire arm, which may aid the future development of soft robotics.We gratefully acknowledge funding from Grant N00014-19-1-2445 from the Office of Naval Research, Tom McKenna and Marc Steinberg, Program Managers. We also thank the staff of the Marine Resources Center at MBL for assistance with water quality measurements, seawater system maintenance, and collection of food items for octopuses

    Optimization and characterization of silver nanoparticle synthesis from the microalgae, Isochrysis galbana

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    The present study was aimed to carry out a green synthesis of Silver Nano Particless by using marine micro algae and its characterization by SEM, EDAX, Particle analyzer and Zeta potential. Microalgae samples (Isochrysis galbana and Nannochloropsis sp.) were collected from phytoplankton laboratory, Tuticorin Research Centre of ICAR-Central Marine Fisheries Research Institute. The culture media of I. galbana and Nannochloropsis sp. were taken for the preliminary synthesis of SNPs. Hence, Nannochloropsis sp. was not synthesized for its SNPs, I. galbana was selected for further study. Culture media, cell filtrate and supernatant of I. galbana were subjected to the SNPs synthesis in order to find out the maximum yield of silver with low chloride content. Among these, the supernatant of I. galbana showed maximum yield with low chloride content. It was confirmed by colorimetric reading at 450 nm. Synthesized SNPs from I. galbana contained 80.68% of silver and 15.25% of chloride as detected by EDAX analysis. Size of the SNPs was analyzed by particle analyzer and ranged from 16.6 to 205.3 nm and average size was 40.6 nm. Zeta potential of SNPs from I. galbana was -44.0 mV, which reveals the high stability of SNPs. This is the first authenticated work of I. galbana with respect to complete characterization of its SNPs

    Synthesis dependent characteristics of Sr1-xMnxTiO3 (x=0.03, 0.05, 0.07 and 0.09)

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    Sr1-xMnxTiO3 (where x = 0.03, 0.05, 0.07 and 0.09) was synthesized via different routes that include solid-state, oxalate precipitation and freeze drying. In oxalate precipitation technique, compositions corresponding to 3 and 5 mol % doping of Mn were monophasic whereas the higher compositions revealed the presence of the secondary phases such as MnO, Mn3O4 etc., as confirmed by high resolution X-ray diffraction (XRD) studies. The decomposition behavior of the precursors prepared using oxalate precipitation method corresponding to the above mentioned compositions was studied. Nanopowders of compositions pertaining to 5 to 9 mol % of Mn doping were obtained using freeze-drying technique. The average crystallite size of these nanopowders was found to be in the 35 to 65 nm range. The microstructural studies carried out on the sintered ceramics, fabricated using powders synthesized by different routes established the fine grained nature (< 1 microm) of the one obtained by freeze drying method. Raman scattering studies were carried out in order to complement the observations made from XRD regarding the phase purity. The dielectric properties of the ceramics obtained by different synthesis routes were studied in the 80 - 300 K temperature range at 100 kHz and the effect of grain size has been discussed.Comment: 38 pages, 4 tables, 13 figure
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