184 research outputs found
Integration of IoT with Blockchain Technology (BIoT) for Data Management and Security Toward Remote Healthcare System (RHS)
No full text
Transport phenomenon in jet impingement baking:
No full textIn food industry, hot air jet impingement ovens are used to bake pizza shells, crackers, cookies, and to toast ready-to-eat cereals. Despite its significant applications and advantages (faster processing and better quality products) in food processing industry, there is a very limited understanding of detailed transport processes (heat and mass transport) involved in jet impingement baking.
To develop quantitative understanding of transport processes during jet impingement baking, we have modeled the flow field and its associated thermal transport phenomenon for a cookie shaped and a hot dog geometry using numerical simulation and have validated it using experimental data. To predict temperature and moisture distribution during baking, we have developed four different baking models based on coupled heat and mass transfer. These models differ based on coupling of heat and mass transport terms, vapor transport, thermodiffusion and stages of a baking process.
Results of flow field and its associated thermal transport studies demonstrated that numerical simulation approach can be used to predict both flow field and thermal transport during jet impingement baking. The results highlight that local and average surface heat transfer coefficient values are a function of nozzle to plate spacing, jet inlet velocity and geometry of target product. Comparison of temperature and moisture profiles among the models show significant differences in temperature and moisture profile. Based on comparison of these models, we established that vapor transport process is important for modeling of a baking process, while thermo-diffusion process does not make a significant contribution to moisture transport. The results also demonstrate that introduction of stages in baking based on empirical approaches can introduce artificial steps in temperature-time profile. Comparison of numerically predicted center point temperature with experimental measurements in a potato disk shows that modified model II (with vapor transport and a single stage baking process) provides the best match with the experimentally measured data. In summary, we have modeled the complete transport process during jet impingement baking, which can predict the baking time, crust thickness, temperature and moisture distributions within the food for a given jet velocity and air temperature.Ph.D.Includes bibliographical references (p. 241-246)by Mark E. Nag
Image Processing Based Approach for Diseases Detection and Diagnosis on Cotton Plant Leaf
No full text
LiDAR-Based Occupancy Grid Map Estimation Exploiting Spatial Sparsity
No full textThe problem of estimating occupancy grids to support automotive driving applications using LiDAR sensor point clouds is considered. We formulate the problem as a sparse binary occupancy value reconstruction problem. Our proposed occupancy grid estimation method is based on pattern-coupled sparse Bayesian learning and exploits the inherent sparsity and spatial occupancy dependencies in LiDAR sensor measurements. The proposed method demonstrates enhanced detection capabilities compared to commonly used benchmark methods, as observed through testing on scenes from the nuScenes dataset.Signal Processing SystemsTeam Nitin Myer
Near-field focusing using phased arrays with dynamic polarization control
No full textPhased arrays in near-field communication allow the transmitter to focus wireless signals in a small region around the receiver. Proper focusing is achieved by carefully tuning the phase shifts and the polarization of the signals transmitted from the phased array. In this paper, we study the impact of polarization on near-field focusing and investigate the use of dynamic polar-ization control (DPC) phased arrays in this context. Our studies indicate that the optimal polarization configuration for near-field focusing varies spatially across the antenna array. Such a spatial variation motivates the need for DPC phased arrays which allow independent polarization control across different antennas. We show using simulations that DPC phased arrays in the near-field achieve a higher received signal-to-noise ratio than conventional switched- or dual-polarization phased arrays.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Nitin MyersMicrowave Sensing, Signals & SystemsSignal Processing System
InFocus: A spatial coding technique to mitigate misfocus in near-field LoS beamforming
No full textPhased arrays, commonly used in IEEE 802.11ad and 5G radios, are capable of focusing radio frequency signals in a specific direction or a spatial region. Beamforming achieves such directional or spatial concentration of signals and enables phased array-based radios to achieve high data rates. Designing beams for millimeter wave and terahertz communication using massive phased arrays, however, is challenging due to hardware constraints and the wide bandwidth in these systems. For example, beams which are optimal at the center frequency may perform poor in wideband communication systems where the radio frequencies differ substantially from the center frequency. The poor performance in such systems is due to differences in the optimal beamformers corresponding to distinct radio frequencies within the wide bandwidth. Such a mismatch leads to a misfocus effect in near-field systems and the beam squint effect in far-field systems. In this paper, we investigate the misfocus effect and propose InFocus, a low complexity technique to construct beams that are well suited for massive wideband phased arrays. The beams are constructed using a carefully designed frequency modulated waveform in the spatial dimension. InFocus mitigates beam misfocus and beam squint when applied to near-field and far-field systems.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Nitin Myer
Binary collision of burning and non-burning droplets of xylene
No full textThe collision behavior of a burning droplet of xylene with a non-burning droplet of xylene is studied. Two piezoelectric droplet generators are used to generate streams of isolated mono-dispersed droplets. These droplet generators are placed vertically opposite to each-other, and the droplets are generated at a frequency of 6 Hz. Droplet diameters range from 80 micro-meters to 95 micro-meters; and droplet velocities vary from 0.7 m/s - 1.5 m/s, for the lower droplet and from 1.5 m/s - 2.5 m/s, for the upper droplet. The droplet streams are confined within a cuvette. The collision occurs at atmospheric pressure, and a constant supply of O2 is maintained in the cuvette to allow burning of the droplet. A CCD strobe is used to detect the two droplets and make adjustments to have them collide. The lower droplet is ignited with a spark. For the experiments, the collision process is recorded using a high-speed camera. The relative velocity and impact parameter of the collisions are varied by changing the supply current to the piezoelectric droplet generators and by moving the lower droplet, respectively. The recorded videos of the collision process are analyzed using a MATLAB script to track the droplets and calculate their velocities and the impact parameter in each case. The collision outcomes are studied under a range of Weber numbers and for varying Impact Parameter. The post-collision behavior of the xylene flame suggests that the gas between the colliding droplets is rapidly ejected, and the flow pattern greatly affects the progression of the flame. With the introduction of burning droplets, existing theoretical models may need to be refined to better predict the onset of various collision regimes.M.S.Includes bibliographical referencesby Rahul Nitin Gandh
Functionalized silicone composites: omniphobic coatings, microspheres and plastic explosives
No full textSilicones are ubiquitous polymers containing a silicon-oxygen backbone and a variety of functional groups that can be tailored to very specific applications. Their flexibility, biocompatibility and relative inertness make them the ideal choice in materials as diverse as cosmetics, defoaming agents in food and medical implants. This thesis will focus on three separate projects, each one a silicone-based composite. Chapter 1 is an overview that includes a brief history, background, synthesis, applications, chemical structure, and any other relevant information regarding silicones.
Chapter 2 describes the successful fabrication of a sprayable omniphobic coating that contains a polydimethylsiloxane binder and nanoparticle ZnO. A coating, or any other surface, is considered omniphobic if it is both water-repellent (i.e. hydrophobic) and oil-repellant (i.e. oleophobic). The coating herein was sprayed on a variety of different surfaces, such as metal mesh, filter paper and bare aluminum, rending them resistant to liquid contamination. The desired application of this coating is to promote efficient heat transfer in condensing pipes by preventing insulating oily films from forming on their interior. By keeping the surface free of films, more heat may be available for transport to the ambient environment.
Chapter 3 describes the synthesis of silicone microspheres via ultrasonic spray pyrolysis. A viable route to silicone microspheres has eluded researchers for many years, in large part due to the very low surface energy of silicone polymers. This prevents a simple emulsion route; the surface energy promotes agglomeration, a problem which cannot be combatted effectively by common surfactants. Microfluidic devices are expensive and afford only low yield and even lower throughput. Thus, we have developed a simple route which nebulizes silicone precursors into micron-sized aerosol droplets and flows the droplets through a furnace tube, where curing and solvent evaporation take place. Since each droplet is its own micro-reactor, each produces a well-formed microsphere with ano observable agglomeration. Furthermore, we can tune the size and composition of these microspheres simply by altering the concentration and components of the precursor.
Chapter 4 describes a series of experiments on silicone-based plastic explosives. There is a paucity of literature regarding the controlled shock impact and subsequent detonation of commonly used explosives. What reports exist rely on computer-modelling and idealized assumptions to make conclusions about the thermomechanical and chemical nature of these events. When an actual explosive is used, it is often loosely packed powder which is of low density and contains many pores and defects. We have devised a method that uses mild-impact sources to generate explosions in a very small amount of explosive material. We incorporate instrumentation that allows us to see, with nanosecond resolution, the temperature and spectral emission of this explosive, under real-life impact conditions.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-05-01The student, Nitin Neelakantan, accepted the attached license on 2017-03-27 at 09:56.The student, Nitin Neelakantan, submitted this Dissertation for approval on 2017-03-27 at 10:02.This Dissertation was approved for publication on 2017-03-27 at 14:03.DSpace SAF Submission Ingestion Package generated from Vireo submission #10620 on 2017-08-10 at 15:05:08Made available in DSpace on 2017-08-10T20:32:44Z (GMT). No. of bitstreams: 2
NEELAKANTAN-DISSERTATION-2017.pdf: 8435180 bytes, checksum: 0128890ff915198d77e2fb1142b3dedf (MD5)
LICENSE.txt: 4214 bytes, checksum: 60a74068ed177dcf9230c046d3102891 (MD5)
Previous issue date: 2017-03-27Embargo set by: Colleen Fallaw for item 102724
Lift date: 2019-08-10T21:27:21Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 102724 on 2019-08-11T09:15:24Z
- …
