94 research outputs found
Heat transfer through a condensate droplet on hydrophobic and nanostructured superhydrophobic surfaces
Get PDFUnderstanding the fundamental mechanisms governing vapor condensation on non-wetting surfaces is crucial to a wide range of energy and water applications. In this thesis, we reconcile classical droplet growth modeling barriers by utilizing two-dimensional axisymmetric numerical simulations to study individual droplet heat transfer on non-wetting surfaces (90° < θ_a < 170°). Incorporation of an appropriate convective boundary condition at the liquid vapor interface reveals that the majority of heat transfer occurs at the three phase contact line, where the local heat flux can be up to 4 orders of magnitude higher than at the droplet top. Droplet distribution theory is incorporated to show that previous modeling approaches under predict the overall heat transfer by as much as 300% for dropwise and jumping-droplet condensation. To verify our simulation results, we study condensed water droplet growth using optical and ESEM microscopy on bi-philic samples consisting of hydrophobic and nanostructured superhydrophobic regions, showing excellent agreement with the simulations for both constant base area and constant contact angle growth regimes. Our results demonstrate the importance of resolving local heat transfer effects for the fundamental understanding and high fidelity modeling of phase change heat transfer on non-wetting surfaces.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2018-05-01The student, Shreyas Chavan, accepted the attached license on 2016-04-25 at 17:05.The student, Shreyas Chavan, submitted this Thesis for approval on 2016-04-25 at 17:16.This Thesis was approved for publication on 2016-04-27 at 09:11.DSpace SAF Submission Ingestion Package generated from Vireo submission #9489 on 2016-07-07 at 13:50:52Made available in DSpace on 2016-07-07T20:35:15Z (GMT). No. of bitstreams: 2
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Previous issue date: 2016-04-27Embargo set by: Seth Robbins for item 93182
Lift date: 2018-07-07T20:35:34Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 93182 on 2018-07-08T09:15:36Z
Smart wearable system for fall detection in elderly people using Internet of Things platform
No full textSliding Window Based Technique to Obtain Correlation Between Field Variables
Get PDFIn agriculture, finding correlation between field variables such as yield, NDVI, etc. is a classic problem. The most popular solution for finding correlation is to use regression analysis over complete field. In a field, there are numerous soil variables such as soil composition, water content, etc. that affect the correlation and it is not always possible to consider such factors in regression model. These factors adversely affect the accuracy of the correlation model. We demonstrate that it is incomplete and inaccurate to represent such correlation using single regression model for the complete field. We propose a novel technique- Sliding Window Based Technique, which finds correlations over small areas, windows, of the field instead of modelling one correlation for entire field. We prove our claims with the help of experiments done on the field data. We evaluate the relationship over multiple window sizes and select appropriate window sizes for further analysis
Phase change phenomena on water repelling and biphilic surfaces
Get PDFThis Dissertation was approved for publication on 2019-04-10 at 09:54.Water-repelling surfaces have been studied for many decades. Hydrophobic and superhydrophobic surfaces are beneficial in phase change heat transfer applications, specifically during condensation because of the enhanced heat transfer and during freezing because of the anti-freezing properties. The current study is focused on enhanced phase change phenomena on superhydrophobic and biphilic surfaces. Hydrophobic surfaces that enable dropwise condensation exhibit 5-10X higher heat transfer. Coalescence induced droplet jumping on superhydrophobic surfaces further increases the heat transfer by 30%. Here, biphilic surfaces consisting of hydrophilic spots on a superhydrophobic background are studied for enhanced condensation. Water droplets nucleating at the hydrophilic spots grow to sizes defined by the biphilic geometry, followed by coalescence and departure. A high fidelity model that captures departure dynamics during droplet jumping on biphilic surfaces and predict the overall condensation heat transfer has been developed. By controlling the spatial geometry and length scale of the hydrophilic spots, enhanced (10X) jumping-droplet condensation heat transfer is obtained.
In terms of freezing and frost formation, understanding the mechanisms of frost formation is essential to a variety of Heating, Ventilating, Air Conditioning and Refrigeration (HVAC&R) applications. When water vapor in the ambient condenses on a chilled substrate in the form of liquid water and then freezes, it is known as condensation frosting. The dominant mechanism governing the spread of condensation frosting is inter-droplet ice bridge frost wave propagation. When a subcooled condensate water droplet freezes on a hydrophobic or superhydrophobic surface, neighboring droplets still in the liquid phase begin to evaporate. The evaporated water molecules deposit on the frozen droplet and initiate the growth of ice bridges directed toward the water droplets being depleted. Neighboring liquid droplets freeze as soon as the ice bridge connects. In this study, the significance of individual droplet freezing on frost wave propagation is studied. 10X slower frost wave propagation speeds on superhydrophobic surfaces are observed. Furthermore, at larger length scales, during bulk freezing of water, it has been shown that superhydrophobic surfaces offer no delay in freezing.
Although frosting delay has been shown with superhydrophobic surfaces, complete elimination of frosting has not been achieved. Given enough time, frosting will initiate and spread to cover the entire surface. In the HVAC&R sectors, the most common approach to remove frost from a surface (defrost) is to reverse the system cycle direction and heat the working fluid. However, water retention on the heat exchanger surface during defrosting decreases the long term heat transfer performance. In this study, the defrosting behavior of superhydrophobic and biphilic surfaces comprising of spatially distinct superhydrophobic and hydrophilic domains is used to accelerate defrosting. During defrosting, biphilic surfaces are shown to exhibit enhanced surface cleaning with no water retention. Furthermore, an ultra-efficient method to defrost a surface covered with ice/frost by focusing energy at the substrate-ice interface is studied. To remove ice/frost efficiently, only the interfacial layer adhering the ice/frost to the solid surface is melted by using a localized ‘pulse’ of heat, allowing gravity or gas shear in conjunction with the ultra-thin lubricating melt water layer to remove the ice/frost. A high fidelity numerical model is developed to simulate pulse defrosting. This work not only provides a fundamental understanding of phase change processes on superhydrophobic and biphilic surfaces, but also elucidates its applications for a plethora of energy industries.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-05-01The student, Shreyas Chavan, accepted the attached license on 2019-04-09 at 16:13.The student, Shreyas Chavan, submitted this Dissertation for approval on 2019-04-09 at 16:16.DSpace SAF Submission Ingestion Package generated from Vireo submission #13540 on 2019-08-22 at 16:20:55Made available in DSpace on 2019-08-23T20:44:41Z (GMT). No. of bitstreams: 2
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Previous issue date: 2019-04-10Embargo set by: Seth Robbins for item 112291
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Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112291
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Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112291
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Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 112291 on 2021-08-24T09:15:24Z
Effect of PV Array Positioning on Mismatch and Wiring Losses in Static Array Reconfiguration
No full textANALYSIS OF PUBLICATION PROFILE OF ACADEMIC LIBRARIANS IN MAHARASHTRA
Get PDFResearch has always been regarded as the most important intellectual activity in the higher education system; therefore this research article aims to provide a comprehensive picture of research productivity in symposia, seminars, conferences, journals, book chapters, research projects and patents carried out by various academic librarians during 2004 to 2013. A questionnaire was designed for data collection and the same was sent to the academic librarians by e-mail/in print. The results indicate that there were total 1325 research productivity in symposia, seminars, conferences, journals, book chapters, research projects and patents during the year 2004 to 2013. Highest 405 (30.57%) research papers published in conferences. Maximum 28.98% research publications appeared during the year 2013. Dr. S.P. Chavan was the most prolific author he has published 85 (6.41%) research papers. Librarian preferred English language to write research papers. Researchers communicated their research through variety of communication channels. The librarian mostly preferred to journals for communication channel. Highest 57 (74.03%) librarians have used single authorship pattern for their publications. Mostly 68 (88.31%) librarians have attending the workshops/symposia/seminars/conferences to acquire new skills, latest technology, update knowledge
Subdued Voices: Women Characters and Their Author in Inside the Haveli
No full textRama Mehta is an eminent novelist who contributed significantly to Indian English fiction by bringing female issues to the fore through her exemplary novel, Inside the Haveli. The novel shows a predominant concern with the subjugating condition of women characters shackled in the Indian patriarchal structure and brings, particularly, into light the repressed state of female characters and the elements that determine their submission. Simultaneously, based on the incident, the novel reveals silence and submission on the part of the novelist as well. Nevertheless, the work seems stifled when dealing with women's issues; its movements are confusing, contradicting and oscillating. The characters and their author appear tense under pressure showing a disinclination to adopt a bold stance. This cramped and oscillating situation speaks of their helplessness and repressed situation
Green synthesis of silver Nanoparticle using Carica Papaya and study there Biochemical Application
No full textAbstract: The nanopartical offer several advantages over other conventional drug delivery systems. Nanoparticles have gained importance in technological advancements due to their modifiable physical, chemical and biological properties with improved performance over their bulk foils. Nanoparticles can simply move in the body due to their small size and reach very complex organs through divers routes. The high stability, controlled drug release makes nanoparticles the most suitable drug delivery system. The study of different methods of synthesis of nanoparticles is essential to obtain desired nanoparticle with specific sizes and shapes. They are suitable candidates for various marketable and local application, which include imaging, catalysis medical application and environmental application.
Keywords: Nanopartical, bulk foil, divers routes.
Title: Green synthesis of silver Nanoparticle using Carica Papaya and study there Biochemical Application
Author: Ms.Pallavi R.Bhagat, Ms. Shubhangi Sahebsingh Rajput, Ms. Shruti Prashant Chavan
International Journal of Interdisciplinary Research and Innovations
ISSN 2348-1218 (print), ISSN 2348-1226 (online)
Vol. 10, Issue 4, October 2022 - December 2022
Page No: 35-39
Research Publish Journals
Website: www.researchpublish.com
Published Date: 06-November-2022
DOI: https://doi.org/10.5281/zenodo.7296295
Paper Download Link (Source)
https://www.researchpublish.com/papers/green-synthesis-of-silver-nanoparticle-using-carica-papaya-and-study-there-biochemical-applicationInternational Journal of Interdisciplinary Research and Innovations, ISSN 2348-1218 (print), ISSN 2348-1226 (online), Research Publish Journals, Website: www.researchpublish.co
Subdued Voices: Women Characters and their Author in Inside the Haveli
Get PDFRama Mehta is an eminent novelist who contributed significantly to Indian English fiction by bringing female issues to the fore through her exemplary novel, Inside the Haveli. The novel shows a predominant concern with the subjugating condition of women characters shackled in the Indian patriarchal structure and brings, particularly, into light the repressed state of female characters and the elements that determine their submission. Simultaneously, based on the incident, the novel reveals silence and submission on the part of the novelist as well. Nevertheless, the work seems stifled when dealing with women's issues; its movements are confusing, contradicting and oscillating. The characters and their author appear tense under pressure showing a disinclination to adopt a bold stance. This cramped and oscillating situation speaks of their helplessness and repressed situation
Hardware Implementation of Novel Shade Dispersion PV Reconfiguration Technique to Enhance Maximum Power under Partial Shading Conditions
No full textPartial shade condition is a significant factor contributing to the PV panel performance in mismatch losses and power generation. The technique suggested in this study allows the physical rearrangement of the PV panel to distribute the shade on the entire PV array. MPPT, selecting suitable inverter topology, or PV panel reconfiguration enhances the performance of the PV panel. This study proposes a new shade dispersing method, novel shade dispersion (NSD). It compares the performance of the NSD method with conventional configurations (CCs). This research article models and simulates 6 × 6 PV array configurations such as Series-Parallel (SP), Total-Cross-Tide (TCT), Bridge-Linked (BL), Honey-Comb (HC), and the newly proposed NSD method under non-shading and nine different partial shading cases. The performance indices used for comparative analysis are global maximum power points, efficiency, power enhancement, open circuit voltage, short circuit current, and number of crests. The Soltech 1 STH-215-P PV module was selected in the MATLAB/Simulink environment to simulate PV array arrangements. Hardware experiments validate the performance of the NSD method
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