3,055 research outputs found
Performance Analysis of MS Patch Antenna with EBG structure
A Microstrip patch antenna design is characterized and optimized using HFSS antenna simulation software. In this thesis we will see the effects of EBG structures with Microstrip patch antenna. Microstrip patch antennas became very popular because of ease of analysis and fabrication, and their attractive radiation characteristics. But also, they have some drawbacks of low efficiency, narrow bandwidth and surface wave losses. We will discuss only about surface waves and its losses. In order to overcome this limitation, EBG (Electromagnetic Band gap) Structures are inserted in the Microstrip Patch Antenna and due to this MS Antenna performance is improved. These periodic structures have the unique property of preventing the propagation of electromagnetic waves for specific frequencies and directions. The aim of this project is to design and simulate the new EBG structures operating at 2.4GHz resonant frequency and study the performance of the rectangular Microstrip patch antenna with and without EBG structure. The substrate material is changed from RT Duroid (material in nominal HFSS design) to FR4 due to lower cost and availability. The operating frequency is changed from 2.3GHz (specified in nominal HFSS design) to 2.4GHz for wireless communication applications. Required dimensional adjustments when changing substrate materials and operating frequencies for this antenna are non-trivial and the new design procedure is used to tune the antenna. The experimental results are compared to theoretical predictions. The results show that the new design procedure can be successfully applied to Microstrip patch antenna design
Automating the Surveillance of Mosquito Vectors from Trapped Specimens Using Computer Vision Techniques
Among all animals, mosquitoes are responsible for the most deaths worldwide.
Interestingly, not all types of mosquitoes spread diseases, but rather, a
select few alone are competent enough to do so. In the case of any disease
outbreak, an important first step is surveillance of vectors (i.e., those
mosquitoes capable of spreading diseases). To do this today, public health
workers lay several mosquito traps in the area of interest. Hundreds of
mosquitoes will get trapped. Naturally, among these hundreds, taxonomists have
to identify only the vectors to gauge their density. This process today is
manual, requires complex expertise/ training, and is based on visual inspection
of each trapped specimen under a microscope. It is long, stressful and
self-limiting. This paper presents an innovative solution to this problem. Our
technique assumes the presence of an embedded camera (similar to those in
smart-phones) that can take pictures of trapped mosquitoes. Our techniques
proposed here will then process these images to automatically classify the
genus and species type. Our CNN model based on Inception-ResNet V2 and Transfer
Learning yielded an overall accuracy of 80% in classifying mosquitoes when
trained on 25,867 images of 250 trapped mosquito vector specimens captured via
many smart-phone cameras. In particular, the accuracy of our model in
classifying Aedes aegypti and Anopheles stephensi mosquitoes (both of which are
deadly vectors) is amongst the highest. We present important lessons learned
and practical impact of our techniques towards the end of the paper
Implementation of Robotic arm control with Emotiv Epoc
Brain Computer Interface (BCI) has opened up a new hope for people suffering from severe motor disabilities, having no physical activities caused due to disease or injury to the central or peripheral nervous system. A BCI based robotic arm movement control is designed and implemented. The proposed system acquires data from the scalp of subjects a group of sensors. Emotiv EPOC a commercially available EEG headset is used, which analyzes the acquired EEG signals real time. The signals are processed and accordingly commands are issued for different movements which will be based on the characteristic patterns for various facial expressions, human emotions and cognitive actions. The idea is to combine the user intent with a robotic arm to achieve the user initiated motor movements
A NARRATIVE REVIEW OF POST-CORONARY ARTERY BYPASS GRAFT MYOCARDIAL ISCHEMIA AND INFARCTION.
Patients with obstructive coronary artery disease are advised to undergo coronary artery bypass graft (CABG) surgery to enhance survival and quality of life. Patients receive arterial and venous implants to enhance coronary blood flow. There are factors that can cause periprocedural myocardial necrosis and factors that can cause late recurrent angina following CABG. In this article, an endeavor is made to examine these particulars
Properties of simulated sunspot umbral dots
Realistic 3D radiative MHD simulations reveal the magneto-convective
processes underlying the formation of the photospheric fine structure of
sunspots, including penumbral filaments and umbral dots. Here we provide
results from a statistical analysis of simulated umbral dots and compare them
with reports from high-resolution observations. A multi-level segmentation and
tracking algorithm has been used to isolate the bright structures in synthetic
bolometric and continuum brightness images. Areas, brightness, and lifetimes of
the resulting set of umbral dots are found to be correlated: larger umbral dots
tend to be brighter and live longer. The magnetic field strength and velocity
structure of umbral dots on surfaces of constant optical depth in the continuum
at 630 nm indicate that the strong field reduction and high velocities in the
upper parts of the upflow plumes underlying umbral dots are largely hidden from
spectro-polarimetric observations. The properties of the simulated umbral dots
are generally consistent with the results of recent high-resolution
observations. However, the observed population of small, short-lived umbral
dots is not reproduced by the simulations, possibly owing to insufficient
spatial resolution.Comment: Accepted for publication in A&
Synthesis and characterization of biodegradable lignin nanoparticles with tunable surface properties
Lignin nanoparticles can serve as biodegradable carriers of biocidal actives with minimal environmental footprint. Here we describe the colloidal synthesis and interfacial design of nanoparticles with tunable surface properties using two different lignin precursors, Kraft (Indulin AT) lignin and Organosolv (high-purity lignin). The green synthesis process is based on flash precipitation of dissolved lignin polymer, which enabled the formation of nanoparticles in the size range of 45–250 nm. The size evolution of the two types of lignin particles is fitted on the basis of modified diffusive growth kinetics and mass balance dependencies. The surface properties of the nanoparticles are fine-tuned by coating them with a cationic polyelectrolyte, poly(diallyldimethylammonium chloride). We analyze how the colloidal stability and dispersion properties of these two types of nanoparticles vary as a function of pH and salinities. The data show that the properties of the nanoparticles are governed by the type of lignin used and the presence of polyelectrolyte surface coating. The coating allows the control of the nanoparticles’ surface charge and the extension of their stability into strongly basic regimes, facilitating their potential application at extreme pH conditions
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