23 research outputs found
Supplemental video 1 and video 2 to preprint article: Surface acoustic wave integrated microfluidics for repetitive and reversible temporary immobilization of C. elegans
No full textNo audio.The ZIP file contains two supplemental videos to the preprint article: BIORXIV/2022/496864; Surface Acoustic Wave Integrated Microfluidics for Repetitive and Reversible Temporary Immobilization of C. elegans by Nakul Sridhar, Apresio Kefin Fajrial, Rachel L. Doser, Frederic L. Hoerndli, and Xiaoyun Ding
Explicit stochastic schemes for transport in particle-resolved simulations
No full textSubmission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2018-08-01The student, Nakul Nuwal, accepted the attached license on 2016-07-20 at 14:01.The student, Nakul Nuwal, submitted this Thesis for approval on 2016-07-20 at 14:18.This Thesis was approved for publication on 2016-07-21 at 13:31.DSpace SAF Submission Ingestion Package generated from Vireo submission #10017 on 2016-11-10 at 12:27:18Made available in DSpace on 2016-11-10T18:35:31Z (GMT). No. of bitstreams: 10
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Previous issue date: 2016-07-21Stochastic particle-resolved methods are a recent development in atmospheric aerosol modeling. These methods resolve individual aerosol particles to track the information of their composition during a numerical simulation. This enables the detailed analysis of aerosol and gas-phase chemistry, and allows for a more accurate estimate of the aerosol impact on human health and Earth's climate. Transport of all particles in a finite-volume framework can be represented as a stochastic model with each particle having a probability to commute between neighboring grid-cells. This work develops and illustrates the stochastic particle-resolved transport method, which can be used for aerosol transport in atmosphere. The development of the stochastic model was inspired by the passive scalar transport in a predefined velocity field. The model was developed by splitting the transport process into advection and diffusion, and combining them with superposition. Single time-step explicit advection schemes and a Range-kutta numerical scheme were compared to the deterministic advection equation solutions and analytical solutions. The analysis also includes the stochastic modeling of the diffusion process and its results compared to analytical solution. For all cases, a quantification of total error and a numerical convergence analysis is presented.Embargo set by: Seth Robbins for item 95391
Lift date: 2018-11-10T18:35:44Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 95391
Lift date: 2018-11-10T18:37:47Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 95391
Lift date: 2018-11-10T18:39:22Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 95391
Lift date: 2018-11-10T18:43:22Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 95391 on 2018-11-11T10:15:28Z
Trapezoid fractures: report of 11 cases.
No full textAuthor(s) Pre or Post Print Version OnlyPURPOSE: Trapezoid fractures are rare. Mostly single cases reports appear in the literature. The purpose of this study was to review 11 patients treated for trapezoid fractures at our center. METHODS: We reviewed all trapezoid fractures that presented over the past 10 years at our institution. We reviewed case notes regarding mechanism of injury, fracture pattern, mode of diagnosis, and time to diagnosis and treatment. RESULTS: We treated 11 patients for trapezoid fractures over the 10-year period. A correct diagnosis was made in 5 cases on initial evaluation. Most trapezoid fractures were diagnosed on computed tomographic scan. The fracture plane was predominantly sagittal. Coronal fractures could not be diagnosed on plain radiographs. CONCLUSIONS: Fractures of the trapezoid should be suspected from the mechanism of injury, in particular, axial force, and from local tenderness. These fractures may be underdiagnosed. We recommend computed tomography rather than plain radiography alone in case of clinical suspicion. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV
Digital Fountain for Multi-node Aggregation of Data in Blockchains
No full textabstract: Blockchain scalability is one of the issues that concerns its current adopters. The current popular blockchains have initially been designed with imperfections that in- troduce fundamental bottlenecks which limit their ability to have a higher throughput and a lower latency.
One of the major bottlenecks for existing blockchain technologies is fast block propagation. A faster block propagation enables a miner to reach a majority of the network within a time constraint and therefore leading to a lower orphan rate and better profitability. In order to attain a throughput that could compete with the current state of the art transaction processing, while also keeping the block intervals same as today, a 24.3 Gigabyte block will be required every 10 minutes with an average transaction size of 500 bytes, which translates to 48600000 transactions every 10 minutes or about 81000 transactions per second.
In order to synchronize such large blocks faster across the network while maintain- ing consensus by keeping the orphan rate below 50%, the thesis proposes to aggregate partial block data from multiple nodes using digital fountain codes. The advantages of using a fountain code is that all connected peers can send part of data in an encoded form. When the receiving peer has enough data, it then decodes the information to reconstruct the block. Along with them sending only part information, the data can be relayed over UDP, instead of TCP, improving upon the speed of propagation in the current blockchains. Fountain codes applied in this research are Raptor codes, which allow construction of infinite decoding symbols. The research, when applied to blockchains, increases success rate of block delivery on decode failures.Dissertation/ThesisMasters Thesis Computer Science 201
High-concentration measurements with optical aerosol spectrometers by signal fluctuation analysis
No full textOptical aerosol measurement systems can be classified into single-particle counting techniques and ensemble techniques. In single-particle counting instruments, such as optical aerosol spectrometers, each particle is analyzed individually. This allows for the accurate measurement of the number concentration and the size distribution of the measured aerosol. Current aerosol spectrometers suffer from a limited concentration range due to coincidence errors. In contrast, ensemble techniques, such as photometers, are suitable for high-concentration measurements. One major drawback of such instruments is that they only provide information about one aerosol property, which is typically the mass concentration. A new ensemble technique for the simultaneous measurement of two aerosol properties, namely particle size and concentration, was developed and experimentally verified. The results show that the median particle size (D50) of a monodisperse aerosol can be determined with a deviation of about 10 %, and the concentration with a deviation of about 30 %. With individual instrument calibration, the accuracy can be further improved to approximately 5 % with respect to particle size and 10 % with respect to concentration. The method may be either implemented as a standalone measurement device or, as an add-on for e. g. optical particle spectrometers in the form of a high-concentration mode
Development of Micro-Computed Tomography Data Based Simulation Technique For Deformation and Strain Measurement of Densely Packed Electronics
No full textRising pace of innovation and continuously increasing investments in research and developments has resulted in higher value added to each electronics equipment around us. This has also resulted in massive rise in demand in each segment of this industry. As of 2018, the semiconductor industry is the largest sector in the world, worth 574.5 billion in 2018 to 47.73 billion in 2018 to $50.54 billion in 2019. A large part of this budget is annually allocated behind the research, development and procurement of missile or missile related technologies.
Constant efforts are made to maximize the life of the electronics used in the missiles and study the Remaining Useful Life of these electronics to improve the cost efficiency of the missile program. Improvements in maximizing the life of electronics or the remaining useful life, requires understanding of the current in-situ condition of the electronics used in these systems. This requires researchers be able to quantify and analyze the amount of deformations the small electrical sub-assemblies inside the systems may observe over its service life. This data can then be used to predict the failure or analyze the extent of damage to predict and quantify its performance over its remaining life.
The existing popular methods used by the US Missile Command involves destructive testing of statistically representative selected samples of missile electronics which results in significant expensive. As per the Stockpile Recovery Program launched in 2015, performing simulations in of (mathematical models) has been cited as one of the ways to reduce the cost per unit of each missile and thus gain much required cost efficiency. This dissertation is thus on the development of non- destructive, non-invasive simulation and experimental techniques to quantify the deformation and strain occurring on the inside of the fuze electronics used in missile systems.
In this study the Author has used micro-computed tomography (micro-CT) data to make Finite Element models of a comprehensive fuze assembly and used the same micro-CT data to make experimental deformation measurements using a technique called Digital Volume Correlation.
Over the life cycle of a missile, the missile electronics are subjected to two categories of loading scenarios. One at the time of manufacturing and storage and other, during its service life. During manufacturing and storage, the electrical assemblies are subjected residual stresses left by the curing of potting thermoset resins or underfills and long hours of thermal aging during storage. During the service life, high-g and low-g mechanical shocks, vibration and sudden temperature changes are the most common forms of loading experienced by missile electronics. In order to protect the electrical assemblies and components from these mechanical and thermal loads, they are often potted within thermoset adhesives. This design further makes the strain and deformation quantification more challenging as the electrical components and assemblies are hidden from the line of sight.
While current methods involve experimentation and testing on a sample set at intermittent stages during the life cycle of a missile, these methods are often destructive in nature. This study is based on use of micro-CT scan data to measure deformations and strains occurring on these electrical components, hidden from the line of sight due to protective adhesives. This is done using Finite element models (simulation technique) and use of micro-CT scan data based Digital Volume Correlation (experimental technique).
Conventional FE modeling approach is found to be prohibitively time consuming for modeling densely packed electrical assemblies. CAD modeling, assembly and meshing of numerous electrical components, big and small, with varied different material models is found to be the bottle neck and thus little to no literature exists on doing FE modeling of comprehensive fuze assemblies. This work involves development of a novel FE modeling strategy using micro-CT data to overcome the problem. An application of this technique would be to perform FE simulations of any field extracted electrical assemblies at any stage of its service life.
Digital Volume Correlation is a technique analogous to Digital Image Correlation for computing deformations and strains in a non-contact manner utilizing the voxel/pixel intensity data. This study reports on use of this technique to experimentally monitor the physical integrity of the electrical components by comparing two micro-CT scans and computing deformations and strains the components would have experienced over a particular time frame. A further application of this technique is explored by quantifying damage progression in the electronics as a function of time over the entire 3D domain on the assembly.
Chapter 1 gives a detailed introduction and literature review on the relevant topics. Chapter 2 denotes a brief introduction to X-ray micro-CT systems, micro-CT data and its usability. A detailed account of the simulation and experimental technique is given in Chapter 3. Chapter 3 also enlists case studies done to explore the capabilities of the technique developed. Chapter 4 and 5 are based on applications of the technique developed to investigate effect of voids in solder joints found in a popular electronic packaging in the present-day consumer electronics followed by Conclusions and Discussion in Chapter 6 and 7
Feedback Error Learning for Rhythmic Motor Primitives
No full text18.10.13 KB. Ok to add the author version to spiral. IEE
An Investigation into the Ancillaries, Parallel Operation of Machines with Voltage Source Inverters, and Development of Switched Capacitor Converters for a Microgrid
No full textWith the increase in energy demand worldwide, there is a push towards integrating distributed generation (DG) in parallel with the utility grid at the distribution level. The DGs are integrated into the electrical network either through power-converters or rotating machines. Several such DGs and loads form a microgrid that can operate either in grid-connected or islanded mode. There are several technical challenges which need to overcome for the reliable operation of such microgrid. In this thesis, the author tries to propose some relevant solutions for the enhancement of microgrid operation.
The thesis is broadly divided into three-part. The first part is about the ancillaries for the testing and performance enhancement of the microgrid. When connected to the utility, the DG needs to follow certain standards demanded by the utility like voltage ride-through, voltage support and fault ride-through. Also, power-converter based DG, when connected to a weak grid, exhibits stability issue. A virtual impedance-based grid emulator is proposed in this thesis to test whether DG meets these requirement specifications before commissioning. With the proposed grid emulator, the DG performance under various scenarios like voltage sag, voltage harmonics and weak grid can be analysed. The other main requirement from the utility is that the connecting DG must possess anti-islanding capabilities. A parallel RLC resonant load per the DG rating is required to test the effectiveness of the anti-islanding algorithm. A power-converter-based RLC load emulator is proposed to test both rotating machine and power converter-based DGs' anti-islanding capability.
A significant portion of the loads in a microgrid is a single phase in nature. The distributive nature of these loads among the three phases results in an unbalanced flow of current. An active phase router is proposed for dynamically switching single-phase loads between the phases to minimise the unbalance in line current. The switching instance is selected to minimise the transients seen by the load. In combination with a power converter-based sequence compensator, the phase router can perfectly balance the phase currents.
The second part of the thesis is about the parallel operation of voltage source inverter (VSI) and rotating machines-based DG. When two of them are operated in parallel, there is a poor transient power-sharing between them because of the machine's higher transient impedance. A control method is proposed in this thesis for the parallel operation of a doubly-fed induction generator (DFIG) and VSI. In the proposed control, the DFIG is operated as a current-controlled voltage source, and thereby the issue with the transient load sharing is mitigated.
Apart from the passive loads, the microgrid can have active loads like active front-end (AFE) converters which behaves like a constant power load. A linearised state-space model of the complete system is developed to study the interaction between such loads and rotating machine-based DG. The dependency of the different controller parameters of the DG and the AFE converter on the stability is analysed through eigenvalue analysis. The developed analysis can further be used for co-design of the control of the DG and AFE converter.
The third part of the thesis is a collaborative work on the switched capacitor (SC) converter for Photovoltaic/Battery grid interface, between Indian Institute of Science Bangalore and the Loughborough University, UK as part of the Joint UK-India Clean Energy initiative (JUICE). A new switched capacitor topology is devised for high-power high-voltage application. The proposed topology has the advantages in terms of capacitor volt-ampere (VA) rating, active switch voltage rating and zero current switching. Two variants of the proposed SC converter topology are also presented with a minimum number of resonant inductors
Functional traits of a plant species fingerprint ecosystem productivity along broad elevational gradients in the Himalayas [Dataset]
No full textTo respect the intellectual property rights, protect the rights of data authors, expand services of the data center, and evaluate the application potential of data, data users should clearly indicate the source of the data and the author of the data in the research results generated by using the data (including published papers, articles, data products, and unpublished research reports, data products and other results). For re-posting (second or multiple releases) data, the author must also indicate the source of the original data.
Example of acknowledgement statement is included below: The data set is provided by National Tibetan Plateau / Third Pole Environment Data Center (http://data.tpdc.ac.cn).1. It is challenge to scale-up from simplified proxies to ecosystem functioning since the inherent complexity of natural ecosystems hinders such an approach. One way to address this complexity is to track ecosystem processes through the lens of plant functional traits. Elevational gradients with diverse biotic and abiotic conditions offer ideal settings for inferring functional trait responses to environmental gradients globally. However, most studies have focused on differences in mean trait values among species and little is known on how intraspecific traits vary along wide elevational gradients and how this variability reflects ecosystem productivity.2. We measured functional traits of the sub-shrub Koenigia mollis (Basionym: Polygonum molle) (a widespread species) in 11 populations along a wide elevational gradient (1515-4216 m) considering from subtropical forest to alpine biomes treeline in the central Himalayas. After measuring different traits (plant height, specific leaf area, leaf area, length of flowering branches, leaf carbon isotope – δ 13C, leaf carbon and leaf nitrogen concentrations), we investigated drivers on changes of these traits and also characterized their relationships with elevation, climate and net primary productivity (NPP).3. All trait values decreased with increasing elevation, except for δ 13C that increased upwards. Likewise, most traits showed strong positive relationships with potential evapotranspiration (PET), while δ 13C exhibited a negative relationship. In this context, elevation-dependent water-energy dynamics is the primary driver of trait variations. Further, five key traits (plant height, specific leaf area, leaf carbon, leaf nitrogen and leaf δ 13C) explained 90.45% of variance in NPP.4. Synthesis. Our study evidences how elevation-dependent climate variations affect ecosystem processes and functions. Intraspecific variability in functional traits is strongly driven by changes in water-energy dynamics, and reflects changes in community productivity over elevation. K. mollis, with one of the widest elevational ranges known to date, could be a model species to infer functional trait responses to environmental gradients globally. This study sheds new insight on how plants modify their basic ecological strategies to cope with changing environments.National Science and Technology Major Project of China: Second National Science and Technology and Research Programme (STEP)（2019QZKK0000）Peer reviewe
How Reproducible are Surface Areas Calculated from the BET Equation?
No full textChemE/Catalysis Engineerin
