1,169 research outputs found
UWB Slotted Circular Disc Monopole Antenna with Inverted U Shaped Defected Ground Plane for Brain Cancer Detection
In this paper the new design of UWB inscribed slotted circular disc monopole antenna is used in the detection of brain cancer is presented. The proposed antenna design consists of circular patch and the bandwidth is increased to cover the UWB frequency range of 3.2 GHZ to 10.6GHZ by embedding square shaped slot cut at the centre and a pair of inverted U shaped cut in the ground plane which gives a defected ground structure that provides the fractional bandwidth more than 110%[3.2 -10.6GHZ]. The proposed antenna is designed and fabricated for brain cancer detection. FR4 substrate is used with printed circular monopole radius of 15mm and with finite ground plane of (60mm x 50mm). It is designed with thick substrate with the thickness of h=1.6mm and high dielectric constant of εr=4.4. The voltage standing wave ratio is of (1-1.5). The proposed antenna design provides minimum return loss, better fractional bandwidth, satisfactorily radiation pattern
Testing of Paraffin-based Hybrid Rocket Fuel using Gaseous Oxygen Oxidiser
A series of paraffin-based hybrid rocket fuel has been studied experimentally in a laboratory-scale motor. To enhance the regression rate of paraffin solid fuel, three types of grain configurations: Cylindrical, star, and helical grain configurations of paraffin wax have been developed and tested with gaseous oxygen. The helical fuel grain presented best performance among all the test ports. About 40.2 per cent and 20.6 per cent regression rates are increased by burning paraffin fuel with helical and star grain configuration respectively, as compared to cylindrical grain configuration at Gox=0.0191 g/mm2s. The regression rates were significantly influenced by the oxygen injection pressure varied between 344.7 kPa and 620.5 kPa. Furthermore, the experimentally obtained exponents of oxidizer mass flux for all three grain configurations have been found to be significantly different from those of the classical hybrid system. Finally, thrust-time traces for all three grain configurations were also studied. The result shown no significant increase or decrease in the amplitude of the thrust oscillations.Defence Science Journal, 2012, 62(5), pp.277-283, DOI:http://dx.doi.org/10.14429/dsj.62.234
Recommended from our members
Chemical and electrochemical synthesis and deposition of chalcogenides from room temperature ionic liquids
Room temperature electrochemical methods to deposit thin films of chalcogenide glasses.Board of Regents, University of Texas Syste
Thermal optical non-linearity of nematic mesophase enhanced by gold nanoparticles – an experimental and numerical investigation
In this work the mechanisms leading to the enhancement of optical nonlinearity of nematic liquid crystalline material through localized heating by doping the liquid crystals (LCs) with gold nanoparticles (GNPs) are investigated. We present some experimental and theoretical results on the effect of voltage and nanoparticle concentration on the nonlinear response of GNP-LC suspensions. The optical nonlinearity of these systems is characterized by diffraction measurements and the second order nonlinear refractive index, n 2 , is used to compare systems with different configurations and operating conditions. A theoretical model based on heat diffusion that takes into account the intensity and finite size of the incident beam, the nanoparticle concentration dependent absorbance of GNP doped LC systems and the presence of bounding substrates is developed and validated. We use the model to discuss the possibilities of further enhancing the optical nonlinearity
Recommended from our members
Chemical and electrochemical synthesis and deposition of chalcogenides from room temperature ionic liquids
Room temperature electrochemical methods to deposit thin films of chalcogenide glasses.Board of Regents, University of Texas Syste
Evaluation of Energy Values of Various Oil Sources when Fed to Broiler Chicks
The nitrogen-corrected apparent metabolizable energy (AMEn) values of seven different oil and fat sources used in broiler diets, primarily across the Midwestern US, were determined in a digestibility experiment. Fifteen days old, Ross 308 male broiler chicks were fed diets containing each oil or fat source at 0%, 3%, 6%, and 9% inclusion levels for 7 days before excreta samples were collected to analyze AMEn on day 21. The AMEn was calculated using 2 different methods, including a linear equation slope method as well as calculating the difference between basal diet and oil containing diets. The AMEn values determined by linear equation slope method for the oil and fat sources were generally in line with historic data. Differences in animalvegetable blended fats were observed and care should be given when using these sources in feed formulations. Direct comparison of the excess energy contributed by the 3% diets provided an average of 69% increase over the energy value derived from the equations. This increase in estimated energy can be attributed to an extra caloric effect of the additional fat due to increased digesta transit time and absorption rate of dietary energy
Surface wave control for large arrays of microwave kinetic inductance detectors
Large ultra-sensitive detector arrays are needed for present and future
observatories for far infra-red, submillimeter wave (THz), and millimeter wave
astronomy. With increasing array size, it is increasingly important to control
stray radiation inside the detector chips themselves, the surface wave. We
demonstrate this effect with focal plane arrays of 880 lens-antenna coupled
Microwave Kinetic Inductance Detectors (MKIDs). Presented here are near field
measurements of the MKID optical response versus the position on the array of a
reimaged optical source. We demonstrate that the optical response of a detector
in these arrays saturates off-pixel at the dB level compared to the
peak pixel response. The result is that the power detected from a point source
at the pixel position is almost identical to the stray response integrated over
the chip area. With such a contribution, it would be impossible to measure
extended sources, while the point source sensitivity is degraded due to an
increase of the stray loading. However, we show that by incorporating an
on-chip stray light absorber, the surface wave contribution is reduced by a
factor 10. With the on-chip stray light absorber the point source response
is close to simulations down to the dB level, the simulation based on
an ideal Gaussian illumination of the optics. In addition, as a crosscheck we
show that the extended source response of a single pixel in the array with the
absorbing grid is in agreement with the integral of the point source
measurements.Comment: accepted for publication in IEEE Transactions on Terahertz Science
and Technolog
Eliminating stray radiation inside large area imaging arrays
With increasing array size, it is increasingly important to control stray
radiation inside the detector chips themselves. We demonstrate this effect with
focal plane arrays of absorber coupled Lumped Element microwave Kinetic
Inductance Detectors (LEKIDs) and lens-antenna coupled distributed quarter
wavelength Microwave Kinetic Inductance Detectors (MKIDs). In these arrays the
response from a point source at the pixel position is at a similar level to the
stray response integrated over the entire chip area. For the antenna coupled
arrays, we show that this effect can be suppressed by incorporating an on-chip
stray light absorber. A similar method should be possible with the LEKID array,
especially when they are lens coupled.Comment: arXiv admin note: substantial text overlap with arXiv:1707.0214
Calibration Scheme for Large Kinetic Inductance Detector Arrays Based on Readout Frequency Response
Microwave kinetic inductance detector (MKID) provides a way to build large
ground based sub-mm instruments such as NIKA and A-MKID. For such instruments,
therefore, it is important to understand and characterize the response to
ensure good linearity and calibration over wide dynamic range. We propose to
use the MKID readout frequency response to determine the MKID responsivity to
an input optical source power. A signal can be measured in a KID as a change in
the phase of the readout signal with respect to the KID resonant circle.
Fundamentally, this phase change is due to a shift in the KID resonance
frequency, in turn due to a radiation induced change in the quasiparticle
number in the superconducting resonator. We show that shift in resonant
frequency can be determined from the phase shift by using KID phase versus
frequency dependence using a previously measured resonant frequency. Working in
this calculated resonant frequency, we gain near linearity and constant
calibration to a constant optical signal applied in a wide range of operating
points on the resonance and readout powers. This calibration method has three
particular advantages: first, it is fast enough to be used to calibrate large
arrays, with pixel counts in the thousand of pixels; second, it is based on
data that are already necessary to determine KID positions; third, it can be
done without applying any optical source in front of the array.Comment: Accepted to Journal of Low Temperature Physics LTD16 Special Issue,
Low Temperature Detector 16 Conference Proceedings,manuscript number:
#JLTP-D-15-00356R1, 6 pages, 5 figure
- …