209 research outputs found
A Foreground Cleaned CMB Map from Non-Gaussianity Measurement
In this paper we present a new method to estimate a foreground cleaned Cosmic
Microwave Background (CMB) map at a resolution of by minimizing the
non-Gaussian properties of the cleaned map which arise dominantly due to
diffuse foreground emission components from the Milky Way. We employ simple
kurtosis statistic as the measure of non-Gaussian properties and perform a
linear combination of 5 frequency maps provided by Wilkinson Microwave
Anisotropy Probe (WMAP) in its 7 year data release in such a way that the
cleaned map has a minimum kurtosis which leads to a non-Gaussianity minimized,
foreground cleaned CMB map. We validate the method by performing Monte-Carlo
simulations. To minimize any residual foreground contamination from the cleaned
map we flag out region near the galactic plane based upon results from
simulations. Outside the masked region our new estimate of CMB map matches well
with the WMAP's ILC map. A simple pseudo- based CMB TT power spectrum
derived from the non-gaussianity minimized map reproduces the earlier results
of WMAP's power spectrum. {\it An important advantage of the method is that it
does not introduce any negative bias in angular power spectrum in low multipole
regime, unlike usual ILC method.} Comparing our results with the previously
published results we argue that CMB results are robust with respect to specific
foreground removal algorithms employed.Comment: 5 pages, 5 figure
Spectrum of SARSCOV2 infection with the efficacy of Covaxin and Covishield vaccines during third wave of COVID-19 pandemic: an experience of a densest state of India
Background: Study was conducted to assess the trend or characteristic of SARSCOV2 infection during 3rd wave of pandemic and to compare the efficacy of Covaxin and Covishield Vaccines.Methods: This descriptive cross-sectional study was conducted with a mixed-method approach (Explanatory sequential mixed method) among the SARSCOV2 infected patients of West Bengal, India on the month of January 2022. In quantitative analysis 277 SARSCOV2 infected patients who were detected as COVID positive within January, were selected randomly from the secondary data source (collected by 20 general practitioners). In qualitative analysis, 11 patients from different categories were interviewed in-depth over the telephone to explain the quantitative data. Bivariate analysis (Mann Whitney U or Kruskal Wallis test) was used as per applicability. Kaplan Meir plot compared the efficacy of Covaxin and Covishield vaccines. Results: Most commonly presented symptom were low-grade fever (78.7%), a mild cough (41.9%), mild cold (62.4%), sore throat (41.9%), body ache (47.3%), and headache (33.2%). Few patients had experienced breathing difficulty (1.4%) and hospitalization (1.1%). Mann Whitney U test significantly (p<0.001) justified that Covaxin receivers have infected in late (median 161 days) comparison to other vaccines receivers (Covishield and Sputnik V median 129 days and 115 days respectively). This finding was also demonstrated in Kaplan Meir Plot.Conclusions: During the 3rd wave of the pandemic, SARSCOV2 infected patients commonly presented with milder symptoms, minimal hospitalization and without any case fatality. Delaying of infection has been observed more among Covaxin receivers compared to others
Numerical Simulation of an Open Channel Ultraviolet Waste-water Disinfection Reactor
The disinfection characteristics of an open channel ultra-violet (UV) wastewater disinfection reactor are investigated using a computational fluid dynamics (CFD) model. The model is based on the volume of fluid method to capture the water-air interface, the Lagrangian particle tracking method to determine the microbial particle trajectory and the discrete ordinate model to calculate the UV intensity field. The numerical predictions are compared with the available experimental data to validate the CFD model. A parametric study is performed to understand the effects of different parameters on the disinfection performance of the reactor. The hydraulic behaviour and the additive nature of disinfection for an open channel reactor with two lamp banks placed in series using different geometric configurations between the two lamp banks are also investigated. A scaling down methodology for the open channel reactor is developed and implemented in the CFD model to understand its applicability
Integrated Approach for Diversion Route Performance Management during Incidents
Non-recurrent congestion is one of the critical sources of congestion on the highway. In particular, traffic incidents create congestion in unexpected times and places that travelers do not prepare for. During incidents on freeways, route diversion has been proven to be a useful tactic to mitigate non-recurrent congestion. However, the capacity constraints created by the signals on the alternative routes put limits on the diversion process since the typical time-of-day signal control cannot handle the sudden increase in the traffic on the arterials due to diversion. Thus, there is a need for proactive strategies for the management of the diversion routes performance and for coordinated freeway and arterial (CFA) operation during incidents on the freeway. Proactive strategies provide better opportunities for both the agency and the traveler to make and implement decisions to improve performance.
This dissertation develops a methodology for the performance management of diversion routes through integrating freeway and arterials operation during incidents on the freeway. The methodology includes the identification of potential diversion routes for freeway incidents and the generation and implementation of special signal plans under different incident and traffic conditions. The study utilizes machine learning, data analytics, multi-resolution modeling, and multi-objective optimization for this purpose. A data analytic approach based on the long short term memory (LSTM) deep neural network method is used to predict the utilized alternative routes dynamically using incident attributes and traffic status on the freeway and travel time on both the freeway and alternative routes during the incident. Then, a combination of clustering analysis, multi- resolution modeling (MRM), and multi-objective optimization techniques are used to develop and activate special signal plans on the identified alternative routes. The developed methods use data from different sources, including connected vehicle (CV) data and high- resolution controller (HRC) data for congestion patterns identification at the critical intersections on the alternative routes and signal plans generation. The results indicate that implementing signal timing plans to better accommodate the diverted traffic can improve the performance of the diverted traffic without significantly deteriorating other movements\u27 performance at the intersection. The findings show the importance of using data from emerging sources in developing plans to improve the performance of the diversion routes and ensure CFA operation with higher effectiveness
Effect Of Bio-Binders On Binder And Mix Properties With High Rap Content
The use of Recycled Asphalt Pavement (RAP) has significantly increased in construction and rehabilitation of flexible pavements to ensure proper utilization of limited natural resources. Recycling also provides a greater environmental benefits and energy conservations. It saves the lands from being the dumping site, conserves energy, and reduces the emission of greenhouse gases. But high RAP in the HMA mix increases the stiffness and may result in cracking. Bio-binders could reduce the stiffness of binder and mixes with high RAP content. Two oils, namely Waste Cooking Oil (WCO), and Soy Oil are potential sources of bio-binder that are abundant and yet to be explored. This research was conducted to explore the effects of selected bio-binders on binder and mixture properties that contain a high percentage of RAP binder. Two different types of aggregates and two virgin binders were used in the study. RAP binder was extracted and modified by the bio-binder. Unaged, Rolling Thin Film Oven (RTFO), and Pressure Aging Vessel (PAV) aged virgin and bio-binder modified RAP binder were tested for both high and low-temperature rheology using Dynamic Shear Rheometer (DSR). Virgin binders were tested as control specimen while 100% RAP binder was used to see the level of modification of RAP binder. These modified binders were further used to make HMA specimens. Nominal maximum aggregate size (NMAS) used for all mixes was 12.5 mm. Eight specimens (150 mm diameter and 75 mm high each) were compacted at a target 7% air void content using gyratory compactor. Asphalt Pavement Analyzer (APA), Semi-Circular Bending (SCB), and Disk-shaped Compact Tension (DCT) tests were conducted to determine the performance properties of the HMA with modified binder. The results showed that modified binder with bio-binder, virgin binder, and high RAP binder maintained/improved the performance properties of HMA
CMB anisotropy power spectrum using linear combinations of WMAP maps
In recent years the goal of estimating different cosmological parameters
precisely has set new challenges in the effort to accurately measure the
angular power spectrum of CMB. This has required removal of foreground
contamination as well as detector noise bias with reliability and precision.
Recently, a novel {\em model-independent} method for the estimation of CMB
angular power spectrum solely from multi-frequency observations has been
proposed and implemented on the first year WMAP data by Saha et al. 2006. All
previous estimates of power spectrum of CMB are based upon foreground templates
using data sets from different experiments. However our methodology
demonstrates that {\em CMB angular spectrum can be reliably estimated with
precision from a self contained analysis of the WMAP data}. In this work we
provide a detailed description of this method. We also study and identify the
biases present in our power spectrum estimate. We apply our methodoly to
extract the power spectrum from the WMAP 1 year and 3 year data.Comment: 38 pages, 17 figure
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