66 research outputs found
Detection of Malaria Parasite Based on Thick and Thin Blood Smear Images Using Local Binary Pattern
No full textAnalysis of PCA and LDA Features for Facial Expression Recognition Using SVM and HMM Classifiers
No full textPhase change phenomena on water repelling and biphilic surfaces
No full textThis 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
CHAVAN-DISSERTATION-2019.pdf: 4984643 bytes, checksum: a8f69aa02defbb72c15006bd7bc4da77 (MD5)
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Previous issue date: 2019-04-10Embargo set by: Seth Robbins for item 112291
Lift date: 2021-08-23T20:44:50Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112291
Lift date: 2021-08-23T20:46:41Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112291
Lift date: 2021-08-23T20:47:38Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112291
Lift date: 2021-08-23T20:48:32Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 112291 on 2021-08-24T09:15:24Z
Multimodality Medical Image Fusion Using M-Band Wavelet and Daubechies Complex Wavelet Transform for Radiation Therapy
No full textMultimodality Medical Image Fusion Using M-Band Wavelet and Daubechies Complex Wavelet Transform for Radiation Therapy
No full textSubdued 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
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
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