8,697 research outputs found
Mass of the black hole in the Seyfert 1.5 galaxy H 0507+164 from reverberation mapping
We present the results of our optical monitoring campaign of the X-ray source
H 0507+164, a low luminosity Seyfert 1.5 galaxy at a redshift z = 0.018.
Spectroscopic observations were carried out during 22 nights in 2007, from the
21 of November to the 26 of December. Photometric observations in the R-band
for 13 nights were also obtained during the same period. The continuum and
broad line fluxes of the galaxy were found to vary during our monitoring
period. The R-band differential light curve with respect to a companion star
also shows a similar variability. Using cross correlation analysis, we
estimated a time delay of 3.01 days (in the rest frame), of the response of the
broad H-beta line fluxes to the variations in the optical continuum at 5100
angstroms. Using this time delay and the width of the H-beta line, we estimated
the radius for the Broad Line Region (BLR) of 2.53 x 10^{-3} parsec, and a
black hole mass of 9.62 x 10^{6} solar mass.Comment: 7 pages, 8 figures, Accepted for publication in MNRA
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Electrospun Piezoelectric Polymer Nanofiber Layers for Enabling in Situ Measurement in High-Performance Composite Laminates
This article highlights the effects from composite manufacturing parameters on fiber-reinforced composite laminates modified with layers of piezoelectric thermoplastic nanofibers and a conductive electrode layer. Such modifications have been used for enabling in situ deformation measurement in high-performance aerospace and renewable energy composites. Procedures for manufacturing high-performance composites are well-known and standardized. However, this does not imply that modifications via addition of functional layers (e.g., piezoelectric nanofibers) while following the same manufacturing procedures can lead to a successful multifunctional composite structure (e.g., for enabling in situ measurement). This article challenges success of internal embedment of piezoelectric nanofibers in standard manufacturing of high-performance composites via relying on composite process specifications and parameters only. It highlights that the process parameters must be revised for manufacturing of multifunctional composites. Several methods have been used to lay up and manufacture composites such as electrospinning the thermoplastic nanofibers, processing an inter digital electrode (IDE) made by conductive epoxy-graphene resin, and prepreg autoclave manufacturing aerospace grade laminates. The purpose of fabrication of IDE was to use a resin type (HexFlow RTM6) for the conductive layer similar to that used for the composite. Thereby, material mismatch is avoided and the structural integrity is sustained via mitigation of downgrading effects on the interlaminar properties. X-ray diffraction, Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, and scanning electron microscopy analyses have been carried out in the material characterization phase. Pulsed thermography and ultrasonic C-scanning were used for the localization of conductive resin embedded within the composite laminates. This study also provides recommendations for enabling internally embedded piezoelectricity (and thus health-monitoring capabilities) in high-performance composite laminates
Neuromorphic In-Memory Computing Framework using Memtransistor Cross-bar based Support Vector Machines
This paper presents a novel framework for designing support vector machines
(SVMs), which does not impose restriction on the SVM kernel to be
positive-definite and allows the user to define memory constraint in terms of
fixed template vectors. This makes the framework scalable and enables its
implementation for low-power, high-density and memory constrained embedded
application. An efficient hardware implementation of the same is also
discussed, which utilizes novel low power memtransistor based cross-bar
architecture, and is robust to device mismatch and randomness. We used
memtransistor measurement data, and showed that the designed SVMs can achieve
classification accuracy comparable to traditional SVMs on both synthetic and
real-world benchmark datasets. This framework would be beneficial for design of
SVM based wake-up systems for internet of things (IoTs) and edge devices where
memtransistors can be used to optimize system's energy-efficiency and perform
in-memory matrix-vector multiplication (MVM).Comment: 4 pages, 5 figures, MWSCAS 201
Clinical and surgical outcomes of 3 cycles versus 6 cycles of neoadjuvant chemotherapy in advanced ovarian carcinoma
Background: Epithelial cancers are the most common ovarian malignancy accounting for 90% of all type of ovarian cancer. Objective of this study was to evaluate the surgical morbidity and to study clinical outcomes of 3 cycles versus 6 cycles of neoadjuvant chemotherapy.Methods: A total 30 women with diagnosis of advanced epithelial ovarian cancer were randomly divided equally to receive either 3 cycles (Group 1) or 6 cycles (Group 2) of neoadjuvant chemotherapy. End points noted were duration of surgery, extent of surgery, perioperative complications and length of stay.Results: Both groups had comparable demographic profile. Surgery was more difficult in early IDS group with lesser percentage of patients achieving minimum intended surgery in early IDS (61.53% versus 80. 47%) peri-operative complications were seen more commonly in early IDS group compared to late IDS group (26.66% versus 69.2%). However mean duration of surgery was similar in both groups. Mean duration of stay in hospital was 5.4 days in late IDS group and 7.6 days in early IDS group. The mean follow-up period in late IDS was 7 months and in early IDS was 5 months. Survival in both groups when patients were followed up till the end of study period (12 months) was similar (p=0.186).Conclusions: Authors conclude that late IDS may be used as a treatment option in the high-risk group of patients. Though there was no significant difference at 6 months follow up, higher percent of women were disease free in late IDS
DWDM-PON/mm-Wave wireless converged Next Generation Access Topology using coherent heterodyne detection
A radio-over-fibre system using coherent optical heterodyne detection scheme is proposed, to achieve seamless integration of a photonic Remote Antenna Unit (RAU) into a Next Generation Dense Wavelength Division Multiplexed Passive Optical Network (NG DWDM-PON). The proposed scheme significantly simplifies the optical mm-wave generation and data recovery as it doesn't require any high-bandwidth modulator at the central office or high-frequency Local Oscillators (LOs) at either the central office or the customer unit; or optical phase-locking techniques to generate the mm-wave wireless signal. A proof-of-concept transmission utilizing 1 Gb/s On-Off Keying is experimentally demonstrated
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