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Modeling and simulation of film blowing processMayavaram, Ravisankar S. 29 August 2005 (has links)
Film blowing process is a flexible mass production technology used for manufacturing
thin polymeric films. Its flexibility in using an existing die to produce films
of different width and thickness, just by controlling process conditions such as, extrudate
velocity, excess pressure, and line speed, makes it an attractive process with
less capital investment. Controlling the process conditions to obtain a stable bubble,
however, is not a trivial task. It is a costly trial and error procedure, which could
result is a large wastage of material and other resources. Hence, it is necessary to
develop methods to simulate the process and design it using numerical experiments.
This important need of the industry defines the objective of this work. In this dissertation,
a transient, axisymmetric, nonisothermal, viscoelastic model is developed
to simulate the process, and it is solved using finite element method. Material behavior
of polymer melt is described using a modified Phan-Thien-Tanner model in
the liquid??like region, and anisotropic Kelvin??Voight model in the solid zone, and
the transition is modeled using a simple mixture theory. Crystallization kinetics is
described using a modified Avrami model with factors to account for the influence
of temperature and strain. Results obtained are compared with available experimental
results and the model is used to explore stability issues and the role of different
parameters. Software developed using this model comes with a GUI based pre- and
post-processor, and it can be easily adapted to use other constitutive models.
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Development of the beta-pressure derivativeHosseinpour-Zoonozi, Nima 25 April 2007 (has links)
The proposed work provides a new definition of the pressure derivative function [that is the ò-derivative
function, ÃÂp òd(t)], which is defined as the derivative of the logarithm of pressure drop data with respect to
the logarithm of time
This formulation is based on the "power-law" concept. This is not a trivial definition, but rather a
definition that provides a unique characterization of "power-law" flow regimes which are uniquely defined
by the ÃÂp òd(t) function [that is a constant ÃÂp òd(t) behavior].
The ÃÂp òd(t) function represents a new application of the traditional pressure derivative function, the
"power-law" differentiation method (that is computing the dln(ÃÂp)/dln(t) derivative) provides an accurate
and consistent mechanism for computing the primary pressure derivative (that is the Cartesian derivative,
dÃÂp/dt) as well as the "Bourdet" well testing derivative [that is the "semilog" derivative,
ÃÂpd(t)=dÃÂp/dln(t)]. The Cartesian and semilog derivatives can be extracted directly from the power-law
derivative (and vice-versa) using the definition given above.
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A Study on EMC Characteristics of Digital TV Receivers for AutomobileLiao, Shih-yi 02 February 2009 (has links)
In general the automotive electromagnetic environment is severe because of the presence of DC motors and ignition. In this thesis, electromagnetic interference and electromagnetic susceptibility are studied. This thesis is divided intro three parts. In Part I we introduce the specification of digital TV (DVB-T) in Taiwan. In Part 2 the reception of digital TV in vehicle and in laboratory is compared. The measurement in vehicle is conducted in order to understand the source of interference and how the disturbance occurs. The standard test in laboratory has to do with the transient susceptibility which is based on ISO 7637. We then analyze the implication of different pulses mandated in ISO 7637. The results are compared with those obtained in vehicular measurement. In Part 3 remedy is proposed to reduce the interference to digital TV.
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Transient deposition of particles with applications to inhaled pharmaceutical aerosolsOphus, Philip S Unknown Date
No description available.
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Åsktransienter och överspänningar : En spänningsfylld simulering av elkraftsystemet vid Forsmark 3Ahlström, Erik January 2014 (has links)
A power system will inevitably be subjected to transient overvoltages, most often produced by switching operations and lightning strikes. These transient overvoltages may harm sensitive equipment without sufficient protection, but it is not an easy task to predict what transients may occur or how they affect the system. A fault occurred in a low voltage system at Forsmark 2012 and overvoltages from lightning were concluded as the probable cause. The three aims with this thesis are to develop and test a model of the power system at Forsmark 3, analyse the transient behaviour of the system when subjected to lightning surges and identify critical parameters, and lastly to provide a tool for investigating the protection of the system. The modelling and simulations were performed in the freely available simulation program LT Spice. Challenges and difficulties have been to obtain parameter values for components that are relevant for the high frequencies produced by the short rise time in lightning surges. The main conclusions are: the maximum current in the lightning discharge has the largest impact on the system voltages and surges in the external grid can produce standing waves in the system, causing significant overvoltages even in low voltage systems. The simulations produced larger overvoltages than would occur in a real system, which also would dampen the high frequency signals to a larger extent. Further work to obtain models better suited for high frequency simulation is suggested.
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A transient gaze2014 September 1900 (has links)
This document explores and questions notions of place, identity, and transformation caused by displacement.
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Power Transformer Transient Modeling Using Frequency Response AnalysisAlharbi, Hosam Salem 15 January 2014 (has links)
Vector Fitting is employed to approximate the Frequency Response Analysis (FRA) measurement data of a 13.8 kV/136.8 kV, 50-MVA single phase transformer. The frequency response of the primary and secondary coils as well the coupling between the coils have been measured in the frequency range of up to 2 MHz. The measured data includes the stray capacitances that exist between the coils. A circuit synthesis model is used to represent the measured data in the form of a two-port passive RLC network. The derived network is implemented in a commonly used power system transient simulator (PSCAD/EMTDC). The proposed RLC model is passive to ensure the stability of the network. The model can be used to investigate transient response of the transformer including the simulation of switching and lightning overvoltage transients. The results are compared with those derived from existing simple models.
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Epi-CHO, an episomal expression system for recombinant protein production in CHO cellsKunaparaju, Raj Kumar, Biotechnology & Biomolecular Sciences, Faculty of Science, UNSW January 2008 (has links)
The current project is to develop a transient expression system for Chinese Hamster Ovary (CHO) cells based on autonomous replication and retention of plasmid DNA. The expression system, named Epi-CHO comprises (1) a recombinant CHO-K1 cell line encoding the Polyoma (Py) virus large T-Antigen (PyLT-Ag), and (2) a DNA expression vector, pPy/EBV encoding the Py Origin (PyOri) for autonomous replication and encoding the Epstein-Barr virus (EBV), Nuclear Antigen-1 (EBNA-1) and EBV Origin of replication (OriP) for plasmid retention. The CHO-K1 cell line expressing PyLT-Ag, named CHO-T was adapted to suspension growth in serum-free media (EXCELL-302) to facilitate large scale transient transfection and recombinant (r) protein production. PyLT-Ag-expressed in CHO-T supported replication of PyOri-containing plasmids and enhanced growth and r- protein production. A scalable cationic lipid based transfection was optimised for CHO-T cells using LipofectAMINE-2000??. Destabilised Enhanced Green Fluorescence Protein (D2EGFP) and Human Growth Hormone (HGH) were used as reporter proteins to demonstrate transgene expression and productivity. Transfection of CHO-T cells with the vector pPy/EBV encoding D2EGFP showed prolonged and enhanced EGFP expression, and transfection with pPy/EBV encoding HGH resulted in a final concentration of 75 mg/L of HGH in culture supernatant 11 days following transfection.
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Surveying Transient Host Galaxies with ASAS-SNBrown, Jonathan S., Jr. 30 October 2018 (has links)
No description available.
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Green Integration of Wafer-scale Two-dimensional MoS2 on Biocompatible and Biodegradable Polymers Towards Transient ElectronicsKaium, Md Golam 01 January 2023 (has links) (PDF)
The concept of transient electronics emerged to minimize E-waste. Ideal transient electronics operate equivalent to conventional electronics, and the entire device disintegrates after a stable operation period. The discovery of graphene opened a new realm of two-dimensional(2D) material science. 2D materials appealed to the attention of the scientific community on account of their combinations of electronic, optical, robust mechanical, and chemical properties that are characteristically distinct from their parental 3D materials. Furthermore, the diverse inclusion of different electronic/optical properties of 2D material makes them advantageous entrants towards novel electronics/ optoelectronics applications. Near atomic thick two-dimensional (2D) molybdenum disulfide (MoS2) terminated with sulfide anions poises minimal toxicity. However, 2D TMDs integrated optoelectronic transient devices and their intrinsic transient characteristics are not extensively explored. A green approach, such as water-assisted integration of 2D MoS2, only requires water and paves the way for integrating 2D MoS2 into any arbitrary substrate, i.e., biodegradable cellulose and Ca-alginate for potential transient electronics. Our studies outlined the feasibility of integrating 2D MoS2 and biodegradable and biocompatible metals/substrates in transient electronics. We drafted a water-assisted green integration of 2D MoS2 on biodegradable cellulose and curved/ tubular natural rubber substrate. We also edged the integration of calcium alginate on 2D MoS2 as an active device component. We demonstrated proof-of-concept 2D MoS2 integrated transient electronics, i.e., pressure sensor, photodetector, biodegradable electrolyte gated 2D MoS2 field effect transistor (FET). In this study, we outlined the dissolution characteristics of 2D MoS2 using food ingredient baking soda buffer solution; furthermore, we studied a novel approach of ultraviolet, UV-triggered degradation of 2D MoS2 on calcium alginate incorporated with riboflavin polymer matrix. Overall, our study sketched the likelihood of integrating 2D MoS2 towards transient electronic devices, and transient characteristics of 2D MoS2 enabled on biodegradable polymers.
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