Mitigation of ammonia and hydrogen sulfide emissions from livestock operations using TiO2 and ZnO nanoparticles

Hazardous gases such as ammonia (NH3) and hydrogen sulfide (H2S) are produced as part of a variety of industrial processes and in livestock production facilities. The emission of these gases poses severe risks to human and animal health, property values as well as to the environment. Several techniques including biological and physicochemical methods have been applied to remove these gases from contaminated air streams. However, most of the work focused on individual ammonia or hydrogen sulfide removal, and use of nanoparticles for simultaneous removal of these two gases has not been done yet. Thus, this work is focused on simultaneous removal of ammonia and hydrogen sulfide from livestock operations using ZnO and TiO2 nanoparticles. Adsorption capacities and isotherms at various temperatures (22 °C, 70 °C, 140 °C and 280 °C) in the concentration range 50-50, 100-100, 200-200, 300-300, 400-400, 500-550 ppmv of NH3-H2S in laboratory scale packed-bed adsorption column was studied and developed. The equilibrium adsorption capacities of both ammonia and hydrogen sulfide increased with an increase of gas concentration. Equilibrium adsorption capacity of hydrogen sulfide increase with the increase of temperature, while there is decrease adsorption capacity of ammonia due to an increase in temperature (22 °C to 280 °C). Control experiments showed that orientation of ZnO and TiO2 nanoparticles layers in the column, as well as utilization of a homogeneous mixture of ZnO and TiO2, had no impact on adsorption capacities (12 mg/g for NH3 and 25.14 mg/g for H2S). Among the evaluated isotherms, Langmuir-Freundlich best described the equilibrium adsorption data. To understand the mechanism of simultaneous removal of NH3 and H2S from gaseous streams, characterization of the unused and exposed adsorbents was conducted by CNHS and TGA. Finally, semi-pilot scale trials using gases emitted from swine manure showed the effectiveness of nanoparticles in the removal of H2S and NH3 from representative gases

Study of Flexural Behaviour of Jeffcott Rotor

The simplest model to study the response of a rotor is a Jeffcott rotor. In this paper the equation of motion of the shaft centre was obtained by using Lagrange’s Equation and the path followed called the orbit was plotted using MATLAB. The amplitude of vibration and phase of an undamped rotor with free whirl, by considering eccentricity and by taking the effect of bow was also plotted separately. The response of the damped rotor was interpreted using Campbell diagram and the motion of shaft centre was plotted separately in a damped rotor. The amplitude and phase of vibration of the rotor geometrical centre was also plotted by considering free whirl, taking eccentricity into account and by taking the effect of bow separately

Essays in Basketball Analytics

With the increasing popularity and competition in professional basketball in the past decade, data driven decision has emerged as a big competitive edge. The advent of high frequency player tracking data from SportVU has enabled a rigorous analysis of player abilities and interactions that was not possible before. The tracking data records two-dimensional x-y coordinates of 10 players on the court as well as the x-y-z coordinates of the ball at a resolution of 25 frames per second, yielding over 1 billion space-time observations over the course of a full season. This dissertation offers a collection of spatio-temporal models and player evaluation metrics that provide insight into the player interactions and their performance, hence allowing the teams to make better decisions. Conventional approaches to simulate matches have ignored that in basketball the dynamics of ball movement is very sensitive to the lineups on the court and unique identities of players on both offense and defense sides. In chapter 2, we propose the simulation infrastructure that can bridge the gap between player identity and team level network. We model the progression of a basketball match using a probabilistic graphical model. We model every touch event in a game as a sequence of transitions between discrete states. We treat the progression of a match as a graph, where each node represents the network structure of players on the court, their actions, events, etc., and edges denote possible moves in the game flow. Our results show that either changes in the team lineup or changes in the opponent team lineup significantly affects the dynamics of a match progression. Evaluation on the match data for the 2013-16 NBA season suggests that the graphical model approach is appropriate for modeling a basketball match. NBA teams value players who can ``stretch'' the floor, i.e. create space on the court by drawing their defender(s) closer to themselves. Clearly, this ability to attract defenders varies across players, and furthermore, this effect may also vary by the court location of the offensive player, and whether or not the player is the ball handler. For instance, a ball-handler near the basket attracts a defender more when compared to a non ball-handler at the 3 point line. This has a significant effect on the defensive assignment. This is particularly important because defensive assignment has become the cornerstone of all tracking data based player evaluation models. In chapter 3, we propose a new model to learn player and court location specific offensive attraction. We show that offensive players indeed have varying ability to attract the defender in different parts of the court. Using this metric, teams can evaluate players to construct a roster or lineup which maximizes spacing. We also improve upon the existing defensive matchup inference algorithm for SportVU data. While the ultimate goal of the offense is to shoot the ball, the strategy lies in creating good shot opportunities. Offensive play event detection has been a topic of research interest. Current research in this area have used a supervised learning approach to detect and classify such events. We took an unsupervised learning approach to detect these events. This has two inherent benefits: first, there is no need for pretagged data to learn identifying these events which is a lobor intensive and error prone task; second, an unsupervised approach allows us to detect events that has not been tagged yet i.e. novel events. We use a HMM based approach to detect these events at any point in the time during a possession by specifying the functional form of the prior distribution on the player movement data. We test our framework on detecting ball screen, post up, and drive. However, it can be easily extended to events like isolation or a new event that has certain distinct defensive matchup or player movement feature compared to a non event. This is the topic for chapter 4. Accurate estimation of the offensive and the defensive abilities of players in the NBA plays a crucial role in player selection and ranking. A typical approach to estimate players' defensive and offensive abilities is to learn the defensive assignment for each shot and then use a random effects model to estimate the offensive and defensive abilities for each player. The scalar estimate from the random effects model can then be used to rank player. In this approach, a shot has a binary outcome, either it is made or it is a miss. This approach is not able to take advantage of the “quality” of the shot trajectory. In chapter 5, we propose a new method for ranking players that infers the quality of a shot trajectory using a deep recurrent neural network, and then uses this quality measure in a random effects model to rank players taking defensive matchup into account. We show that the quality information significantly improves the player ranking. We also show that including the quality of shots increases the separation between the learned random effect coefficients, and thus, allows for a better differentiation of player abilities. Further, we show that we are able to infer changes in the player's ability on a game-by-game basis when using a trajectory based model. A shot based model does not have enough information to detect changes in player's ability on a game-by-game basis. A good defensive player prevents its opponent from making a shot, attempting a good shot, making an easy pass, or scoring events, eventually leading to wasted shot clock time. The salient feature here is that a good defender prevents events. Consequently, event driven metrics, such as box scores, cannot measure defensive abilities. Conventional wisdom in basketball is that ``pesky'' defenders continuously maintain a close distance to the ball handler. A closely guarded offensive player is less likely to take or make a shot, less likely to pass, and more likely to lose the ball. In chapter 6, we introduce Defensive Efficiency Rating (DER), a new statistic that measures the defensive effectiveness of a player. DER is the effective distance a defender maintains with the ball handler during an interaction where we control for the identity and wingspan of the the defender, the shot efficiency of the ball handler, and the zone on the court. DER allows us to quantify the quality of defensive interaction without being limited by the occurrence of discrete and infrequent events like shots and rebounds. We show that the ranking from this statistic naturally picks out defenders known to perform well in particular zones

Tribology and Rotordynamics of Small High-Speed Cryogenic Turboexpander

Turboexpander is considered as the heart of present-day cryogenic process plants such as helium, hydrogen and nitrogen liquefiers, low-temperature refrigerators and air separation units, . The operational objective of a turboexpander is to refrigerate a gas stream, by removing work from the gas, and expanding the gas nearly isentropically. The turbine based cryogenic process plants in recent years are low-pressure system and have the advantage of high thermodynamic efficiency and high reliability. The high efficiency is possible at highspeed of the turboexpander, and these turboexpanders in a typical cryogenic refrigerator or liquefier run at high-speed greater than 50,000 rpm without contaminating the process gas. Such operating condition imposes rigorous constraints on tribo-pair design. Oil-free gas bearings have advanced as the most acceptable solution for supporting small and high-speed cryogenic turboexpander rotors. An inherent issue with classic gas bearing is its lower dynamic properties such as stiffness and damping because of its low viscosity. Low stiffness and damping are prone to instability at high rotational speed. So gas foil bearings (GFBs) have received much attention for research, development, and experiment over past three decades for its ability to tailor the stiffness and damping with the use of compliant foils. Bump type compliant foil gas being is quite popular among researchers for various turbomachines for its high load carrying capacity, simplified numerical analysis, and easy fabrication methodology compared to other types. In the present work, a modest attempt is made to understand, standardize and document the numerical analysis, design methodology and fabrication methodology. It evaluates the rotor bearing performance to determine the feasibility of bump type gas foil bearings for axial and radial support of cryogenic turboexpanders. The work presented in current dissertation classified into five parts. The first part includes the status of research and development in the field of gas bearings in turboexpanders and a broad literature review of gas foil bearings. The outcome of the literature review directs that extensive research is essential for designing and development of gas bearing for a more advanced cryogenic system which is technically and economically better than present gas bearings. The second part deals with the design and numerical analysis of gas foil journal and thrust bearings and its feasibility to apply in a small and high-speed cryogenic turboexpander. The numerical analysis helps to fix the dimensions of foils such as its thickness, bump length, and pitch. for a previously designed rotor and its load carrying capacity. The dynamic properties of the bearings are determined to be used in the rotordynamics analysis. Finally, a step by step detailed design procedure itemized for both the gas foil bearings. Transverse vibration being a major issue for high speed rotating machinery such as a cryogenic turboexpander, a detailed vibration analysis completed in part three. The vibration analysis includes determination of critical speeds, mode shapes and unbalanced response for the desired configuration of the rotor-bearing system with determined stiffness and damping from previous part. A small clearance between the gas bearings and the rotor is maintained in order of 10 to 40 m; This makes a cryogenic turboexpander with gas foil bearing a precision equipment. All precision equipment demands micron scale manufacturing tolerance, so fourth part of the dissertation explains the details design methodology for gas foil bearings, the rotor and other associated parts of turboexpander. A broad analysis is done on bump forming methodology for fabrication of bump foil of the desired dimension. A Finite Element Method (FEM) simulation of forming process carried to simplifies the die design process. Special attention is given to the material selection of bearing components, balancing of the rotor, tolerance analysis, fabrication, coating of solid lubricant and assembly of the turboexpander. The last part includes performance study of the fabricated turboexpander with gas foil journal and thrust bearing. Several issues are encountered during this phase, and most of them are rectified either by modification of design process or rectification in fabrication methodology. A vibration study is done using accelerometers on the bearing housing close to the journal bearings. The vibration analysis reveals gas foil bearings can be an alternative rotor bearing system for a high-speed small sized cryogenic turboexpander. A satisfactory operation is carried out for the duration of 30 hrs with an achievable speed of 81,000 rpm with multiple starts and stops

3-D poling and drive mechanism for high-speed PZT-on-SOI Electro-Optic modulator using remote Pt buffered growth

In this work, we have demonstrated a novel method to increase the electro-optic interaction in an intensity modulator at the C-band by optimizing the growth methodology of PZT with the metal (Ti/Pt) as a base material and the PZT poling architecture. Here, we have used a patterned Pt layer for PZT deposition instead of a buffer layer. By optimizing the PZT growth process, we have been able to do poling of the fabricated PZT film in an arbitrary direction as well as have achieved an enhanced electro-optic interaction, leading to a DC spectrum shift of 304 pm/V and a V{\pi} L{\pi} value of 0.6 V-cm on a Si-based MZI. For an electro-optic modulator, we are reporting the best values of DC spectrum shift and V{\pi} L{\pi} using perovskite as an active material. The high-speed measurement has yielded a tool-limited bandwidth of > 12GHz. The extrapolated bandwidth calculated using the slope of the modulation depth is 45 GHz. We also show via simulation an optimized gap of 4.5 {\mu}m and a PZT thickness of 1 {\mu}m that gives us a less than 1 V-dB.Comment: 7 pages, 5 figures, 1 Tabl

DFT analysis and demonstration of enhanced clamped Electro-Optic tensor by strain engineering in PZT

We report $\approx$400\% enhancement in PZT Pockels coefficient on DFT simulation of lattice strain due to phonon mode softening.The simulation showed a relation between the rumpling and the Pockels coefficient divergence that happens at -8\% and 25\% strain developed in PZT film.The simulation was verified experimentally by RF sputter deposited PZT film on Pt/SiO$_2$/Si layer.The strain developed in PZT varied from -0.04\% for film annealed at 530\degree C to -0.21\% for 600\degree C annealing temperature.The strain was insensitive to RF power with a value of -0.13\% for power varying between 70-130 W. Pockels coefficient enhancement was experimentally confirmed by Si Mach Zehnder interferometer loaded with PZT and probed with the co-planar electrode.An enhancement of $\approx$300\% in Pockels coefficient was observed from 2-8 pm/V with strain increasing from -0.04\% to -0.21\%. To the best of our knowledge, this is the first time study and demonstration of strain engineering on Pockels coefficient of PZT using DFT simulation, film deposition, and photonic device fabrication.Comment: 9 Pages, 4 Figure

Highly Oriented PZT Platform for Polarization-Independent Photonic Integrated Circuit and Enhanced Efficiency Electro-Optic Modulation

We demonstrate, for the first time, sputtered PZT as a platform for the development of Si-based photonic devices such as rings, MZI, and electro-optic modulators. We report the optimization of PZT on MgO(002) substrate to obtain highly oriented PZT film oriented towards the (100) plane with a surface roughness of 2 nm. Si gratings were simulated for TE and TM mode with an efficiency of -2.2 dB/coupler -3 dB/coupler respectively with a polarization insensitive efficiency of 50% for both TE and TM mode. Si grating with an efficiency of around -10 dB/coupler and a 6 dB bandwidth of 30 nm was fabricated. DC Electro-optic characterization for MZI yielded a spectrum shift of 71 pm/V at the c-band.Comment: 11 Pages, 9 Figures, 3 Table