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Articles 12241 - 12270 of 21751

Full-Text Articles in Engineering

Novel Yttrium-Stabilized Zirconia Polymeric Precursor For The Fabrication Of Thin Films, Roger M. Smith, X.-D. Zhou, Wayne Huebner, Harlan U. Anderson Sep 2004

Novel Yttrium-Stabilized Zirconia Polymeric Precursor For The Fabrication Of Thin Films, Roger M. Smith, X.-D. Zhou, Wayne Huebner, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

An acetate-based polymeric precursor for producing yttrium-stabilized zirconia (YSZ) was developed. The precursor was prepared under ambient conditions and contains only yttrium and zirconium cations. Dense, crack-free films were fabricated with this precursor on alumina substrates at a rate of 60 nm per deposition, producing polycrystalline YSZ at temperatures as low as 600 °C. Grain growth in thin YSZ films followed Arrhenius equation with an activation energy approximately 0.45 eV. The residual strain in YSZ films decreased with increasing annealing temperature from 600 to 900 °C.

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Pm Manufacturing Research Boosted By Continuous Sintering Furnace, Joseph William Newkirk Sep 2004

Pm Manufacturing Research Boosted By Continuous Sintering Furnace, Joseph William Newkirk

Materials Science and Engineering Faculty Research & Creative Works

University of Missouri-Rolla has recently acquired a Fluidtherm laboratory continuous sintering furnace. Custom designed and built for PM research, the furnace will allow current efforts in sintering development, pressure gas quenching of PM steels, optimisation of toughness and fatigue properties of PM parts, and production of metal matrix composites to be enhanced and extended.

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Determining Suitability Of A Fly Ash For Silica Extraction And Zeolite Synthesis, Natàlia Moreno, Xavier Querol, Angel López-Soler, José Manuel Andres, Maria Janssen, Henk Nugteren, Mark R. Towler, Kenneth Stanton Sep 2004

Determining Suitability Of A Fly Ash For Silica Extraction And Zeolite Synthesis, Natàlia Moreno, Xavier Querol, Angel López-Soler, José Manuel Andres, Maria Janssen, Henk Nugteren, Mark R. Towler, Kenneth Stanton

Chemical and Biochemical Engineering Faculty Research & Creative Works

Zeolitic material is obtained from fly ash both by direct conversion of the ash or from SiO2 extracts obtained from fly ash. This study focuses on determining the suitability of a fly ash for SiO2 extraction and for zeolite synthesis by direct conversion. The SiO2 extraction experiments from different fly ashes show that the main parameters governing the SiO2 extraction are: (a) a high bulk SiO2 content (> 52%, for obtaining an extraction yield of 100 g SiO2 kg-1) in the starting fly ash, (b) a high proportion (> 55%) of the bulk SiO …

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Steel Deck Institute Diaphragm Design Manual, Third Edition, Larry D. Luttrell Sep 2004

Steel Deck Institute Diaphragm Design Manual, Third Edition, Larry D. Luttrell

CCFSS Library (1939 - present)

No abstract provided.

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Membrane Laminar Wet Electrostatic Precipitator, Hajrudin Pasic, M. Khairul Alam, David J. Bayless Aug 2004

Membrane Laminar Wet Electrostatic Precipitator, Hajrudin Pasic, M. Khairul Alam, David J. Bayless

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A laminar flow, wet electrostatic precipitator (ESP) with planar collecting electrodes preferably made of membranes, such as a woven silica fiber. The collecting electrodes are spaced close to planar discharge electrodes to promote laminar flow (Re<2300). Charging electrodes are positioned upstream of the wet ESP to charge the particulate entering the wet ESP to promote collection. The wet ESP is preferably downstream from a conventional turbulent dry ESP for collecting a substantial portion of the larger particulate in the gas stream prior to the gas stream entering the wet ESP.

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Mixed Ion-Polaron Transport In Na2o-Pbo-Fe2o3-P2o5 Glasses, A. Moguš-Milanković, A. Šantić, Signo Tadeu Dos Reis, K. Furić, D. E. Day Aug 2004

Mixed Ion-Polaron Transport In Na2o-Pbo-Fe2o3-P2o5 Glasses, A. Moguš-Milanković, A. Šantić, Signo Tadeu Dos Reis, K. Furić, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

The electrical and dielectric properties of the xNa2O · (100 - x) · [28.3PbO · 28.7Fe2O3 · 43.0P2O5] (0 ≤ x ≤ 30) glasses were measured by impedance spectroscopy in the frequency range from 0.01 Hz to 3 MHz and the temperature range from 303 to 473 K. the conductivity for glasses containing ≤15 mol% Na2O is predominantly electronic and is controlled by electron hopping between Fe(II) and Fe(III) ions. in these glasses the sodium ions have such a low mobility, caused by ion-polaron interaction, that they make no …

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Electromagnetic Interference Of System On Package, Toshio Sudo, Hideki Sasaki, Norio Masuda, James L. Drewniak Aug 2004

Electromagnetic Interference Of System On Package, Toshio Sudo, Hideki Sasaki, Norio Masuda, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic interference (EMI) issues are expected to be crucial for next-generation system-on-package (SOP) integrated high-performance digital LSIs and for radio frequency (RF) and analog circuits. Ordinarily in SOPs, high-performance digital LSIs are sources of EMI, while RF and analog circuits are affected by EMI (victims). This paper describes the following aspects of EMI in SOPs: 1) die/package-level EMI; 2) substrate-level EMI; 3) electromagnetic modeling and simulation; and 4) near electromagnetic field measurement. First, LSI designs are discussed with regard to radiated emission. The signal-return path loop and switching current in the power/ground line are inherent sources of EMI. The EMI …

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Study Of Ceramic Slurries For Investment Casting With Ice Patterns, Qingbin Liu, Ming-Chuan Leu, Harish Jose, Von Richards Aug 2004

Study Of Ceramic Slurries For Investment Casting With Ice Patterns, Qingbin Liu, Ming-Chuan Leu, Harish Jose, Von Richards

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Ice patterns generated by rapid freeze prototyping or a molding process can be used to make ceramic investment molds for metal castings. Due to the use of ice, the ceramic slurries must be poured around the pattern and cured at sub-freezing temperatures. Success of this process depends greatly on the mold strength after the gelation of the slurries. This paper describes the experimental results of the mold strength after the gelation of the slurries under different compositions. The parameters considered include mixing time, alumino-silicate vs. fused silica ratio, volume of binder, and volume of catalyst. The strength of the gelled …

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Modeling Of The Metal Powder Flow With Carrier Gas In Coaxial Nozzle For Direct Laser Deposition Process, Heng Pan, Frank W. Liou Aug 2004

Modeling Of The Metal Powder Flow With Carrier Gas In Coaxial Nozzle For Direct Laser Deposition Process, Heng Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In direct laser deposition process, metal powder is directly fed with carrier gas through the coaxial nozzle into the melt pool created by the laser to form the solid parts. Many operational parameters of the process depend on the characteristic of the powder stream structure below the exit of the coaxial nozzle. In this paper, a computational approach is developed for the simulation of the gas-particle flow in the coaxial nozzle. By taking into account the nozzle geometry and operating parameters, such as width and inclination angle of powder passage and carrier gas velocity, the developed computational code allows the …

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Development Of Image Processing Tools For Analysis Of Laser Deposition Experiments, Todd E. Sparks Aug 2004

Development Of Image Processing Tools For Analysis Of Laser Deposition Experiments, Todd E. Sparks

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Microscopical metallography is a well established field with a long history of techniques for measuring features. Modern computational power allows much more rigorous investigation than simple area fractions and intercept measurements. This paper details the development of image processing tools using GNU Octave, a free, open source numerical computation package. Proposed in the paper is a method for characterizing features within a digital microscope image.

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Experimental Investigation Of Laser Metal Deposition Of Functionally Graded Copper And Steel, Vinay Kadekar, Sashikanth Prakash, Frank W. Liou Aug 2004

Experimental Investigation Of Laser Metal Deposition Of Functionally Graded Copper And Steel, Vinay Kadekar, Sashikanth Prakash, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser metal deposition is an emerging technology for producing fully dense metallic parts. This process shows a promising future for the deposition of functionally graded steel - copper alloys. Good thermal conductivity of copper and a high wear resistance of steel can be achieved in dies and cores. However, to accomplish this, there are many issues to be resolved, such as the formation of an undesirable phase, solidification cracking, porosity at the interface and difference in thermal coefficient of expansion between steel and copper. The influences of process variables, such as laser power, laser scan speed, composition, powder flow rate, …

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Numerical And Experimental Analysis Of The Powder Flow Streams In The Laser Aided Material Deposition Process, Yogesh D. Thakar, Heng Pan, Frank W. Liou Aug 2004

Numerical And Experimental Analysis Of The Powder Flow Streams In The Laser Aided Material Deposition Process, Yogesh D. Thakar, Heng Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Axial powder stream concentration between the nozzle end and the deposition point is an important process parameter in the laser aided material deposition process. The powder concentration is greatly influenced by the nozzle geometry in use. This paper describes the numerical and experimental analysis of this important parameter in relation to the coaxial nozzle. The experiments are performed with the different nozzle geometries to generate various flow patterns of the gravity fed powder in a cold stream. The results of the experimental analysis are compared with the numerical simulation and found justified. These results are used in concluding the significance …

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Ccfss Technical Bulletin Fall 2004, Wei-Wen Yu Center For Cold-Formed Steel Structures Aug 2004

Ccfss Technical Bulletin Fall 2004, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Technical Bulletins (1993 - 2020)

No abstract provided.

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A Time Domain Approach To Estimate Current Draw From Smt Decoupling Capacitors, Lin Zhang, Bruce Archambeault, Samuel Conner, James L. Knighten, Jun Fan, Norman W. Smith, Ray Alexander, Richard E. Dubroff, James L. Drewniak Aug 2004

A Time Domain Approach To Estimate Current Draw From Smt Decoupling Capacitors, Lin Zhang, Bruce Archambeault, Samuel Conner, James L. Knighten, Jun Fan, Norman W. Smith, Ray Alexander, Richard E. Dubroff, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A time domain approach to investigate and predict impedances and scattering parameters of a DC power bus is proposed. This approach is based on a cavity model and is achieved using a circuit simulation tool - SPICE. A SPICE-based circuit model for triangular power plane segments is described, verified and applied to simulate both the frequency and time domain characteristics of an irregularly shaped two-layer PCB board. Furthermore, the current draw from a surface mount technology (SMT) decoupling capacitor is simulated and estimated using this approach. Near-field electromagnetic loop probes are used to validate the current estimation qualitatively. Additionally the …

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Digital Scr Control Box For Educational Laboratory, Zakdy Sorchini, Jonathan W. Kimball, Philip T. Krein Aug 2004

Digital Scr Control Box For Educational Laboratory, Zakdy Sorchini, Jonathan W. Kimball, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

A "blue box" has been designed to introduce the silicone controlled rectifier (SCR) to power electronics students. SCRs are useful in many real-world applications, and are conceptually important in a student's understanding of power converters. The box is highly flexible in application, and its internal design is simple enough to explain to students. Experiments are shown, both of the type commonly used in the laboratory and of the type used for demonstrations. The box has also been designed to be suitable for research purposes and line voltage applications.

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Extraction Of A Spice Via Model From Full-Wave Modeling For Differential Signaling, Shaofeng Luan, Giuseppe Selli, James L. Drewniak, Andrea De Luca, Giulio Antonini, Antonio Orlandi, Antonio Ciccomancini Scogna, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander Aug 2004

Extraction Of A Spice Via Model From Full-Wave Modeling For Differential Signaling, Shaofeng Luan, Giuseppe Selli, James L. Drewniak, Andrea De Luca, Giulio Antonini, Antonio Orlandi, Antonio Ciccomancini Scogna, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a procedure for building SPICE models for via transitions in differential signaling. The method of extracting parameters of SPICE models from a full-wave simulation tool is demonstrated. Then the validity of the SPICE models is studied by comparing the solution from the SPICE models with that from the full-wave simulation.

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Extraction Of Spice-Type Equivalent Circuits Of Signal Via Transitions Using The Peec Method, Jingkun Mao, James L. Drewniak, Giulio Antonini, Antonio Orlandi Aug 2004

Extraction Of Spice-Type Equivalent Circuits Of Signal Via Transitions Using The Peec Method, Jingkun Mao, James L. Drewniak, Giulio Antonini, Antonio Orlandi

Electrical and Computer Engineering Faculty Research & Creative Works

Digital devices and discontinuities are typically analyzed by inserting their equivalent circuits into SPICE-type simulators. The partial element equivalent circuit method has been proven to be very useful for electromagnetic modeling. It can be used in both the time and the frequency domain. In this paper, the PEEC technique is employed as an efficient full-wave modeling tool to derive SPICE-type equivalent circuits of signal via transition structures. A nodal analysis technique is utilized in conjunction with the optimization algorithm to extract the equivalent circuits, whose component values are the parameters optimized. The good agreement between different approaches demonstrates that the …

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Radiation Mechanisms For Semiconductor Devices And Packages, Todd H. Hubing, Daryl G. Beetner, Shaowei Deng, Xiaopeng Dong Aug 2004

Radiation Mechanisms For Semiconductor Devices And Packages, Todd H. Hubing, Daryl G. Beetner, Shaowei Deng, Xiaopeng Dong

Electrical and Computer Engineering Faculty Research & Creative Works

VLSI semiconductor devices are often the source of radiated electromagnetic emissions from electronic devices. Noise coupled from these devices to resonant structures on the printed circuit board, resonant cables or resonant enclosures can result in EMI problems that are difficult or expensive to solve at the board or system level. This paper reviews three mechanisms by which noise can be coupled from semiconductor devices and packages resulting in radiated electromagnetic emissions.

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A Cn-Fdtd Scheme And Its Application To Vlsi Interconnects/Substrate Modeling, Rui Qiang, Dagang Wu, Ji Chen, Chen Wang, James L. Drewniak Aug 2004

A Cn-Fdtd Scheme And Its Application To Vlsi Interconnects/Substrate Modeling, Rui Qiang, Dagang Wu, Ji Chen, Chen Wang, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a two-dimensional (2D) Crank-Nicholason (CN) finite difference time domain (FDTD) method is proposed for VLSI interconnect/substrate characterization. Through rigorous truncation and dispersion error analyses, a guideline on using this technique is presented. Several iterative solvers are investigated to accelerate the solution of the CN-FDTD scheme. Numerical examples are given to demonstrate the accuracy and the efficiency of the proposed algorithm.

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Induced Defects In Carbonaceous Materials For Hydrogen Storage, Angela D. Lueking, Caroline E. Burgess Clifford, Deepa L. Narayanan Aug 2004

Induced Defects In Carbonaceous Materials For Hydrogen Storage, Angela D. Lueking, Caroline E. Burgess Clifford, Deepa L. Narayanan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The induced defects in carbonaceous materials for hydrogen storage were studied. The effect of exfoliation was studied and the graphite nanofibers (GNF) diameter before and after exfoliation was quantified. Thermal decomposition of the GNF before and after sulfuric/nitric acid exfoliation indicated a clear loss of thermal stability. GNF exfoliation enhanced the hydrogen uptake by a factor of five compared to the untreated GNF. The amorphous carbon was reactive than GNF, and decomposed before the GNF. The higher pretreatment temperature was intended to preferentially remove amorphous carbon leaving a higher purity of exfoliated GNF.

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Defect Characterization And Yield Analysis Of Array-Based Nanoarchitecture, Shanrui Zhang, Minsu Choi, Nohpill Park Aug 2004

Defect Characterization And Yield Analysis Of Array-Based Nanoarchitecture, Shanrui Zhang, Minsu Choi, Nohpill Park

Electrical and Computer Engineering Faculty Research & Creative Works

With molecular-scale materials and fabrication techniques recently developed, high-density computing systems in nanometer domain emerge. An array-based nanoarchitecture has been recently proposed based on nanowires such as carbon nanotubes (CNTs), silicon nanowires (SiNWs). High-density nanoarray-based systems consisting of nanometer-scale elements are likely to have many imperfections; thus, defect-tolerance is considered as one of the most significant challenges. In this paper, we propose a probabilistic yield model for the array-based nanoarchitecture. The proposed yield model can be used 1) to accurately estimate the raw and net array densities, and 2) to design and optimize more defect and fault-tolerant systems based on …

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A New Calibration Method For Current Probes, Ramachandran Chundru, David Pommerenke, Sunitha Chandra Aug 2004

A New Calibration Method For Current Probes, Ramachandran Chundru, David Pommerenke, Sunitha Chandra

Electrical and Computer Engineering Faculty Research & Creative Works

EMC engineers often use current probes to detect common mode currents. It is necessary to characterize the probes up to Giga Hertz frequencies. Existing calibration methods for current clamps suffer from the problem of not directly measuring the current within the current clamp. Instead they either reconstruct the current from measurements at other locations or they use assumptions regarding the geometry which allows them to use a current that is measured at a different location without applying a mathematical correction. The proposed method overcomes these disadvantages by directly measuring the current at the center of the current clamp. This paper …

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The Design Of A Lumped Element Impedance-Matching Network With Reduced Parasitic Effects Obtained From Numerical Modeling, Shaofeng Luan, Jun Fan, James L. Knighten, Norman W. Smith Aug 2004

The Design Of A Lumped Element Impedance-Matching Network With Reduced Parasitic Effects Obtained From Numerical Modeling, Shaofeng Luan, Jun Fan, James L. Knighten, Norman W. Smith

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents an impedance-matching network design with numerical modeling of the parasitic effects. A modeling tool CEMPIE (a Circuit Extraction approach based on a Mixed Potential Integral Equation formulation) is used to model the hoard-level parasitics of surface mount technology (SMT) resistors for impedance-matching networks. A 3-layer design of impedance-matching network with 0402 SMT resistors is implemented according to the modeling results. And its performance is demonstrated.

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Comparison Of Via Equivalent Circuit Model Accuracy Using Quasi-Static And Full-Wave Approaches, Bruce Archambeault, Samuel R. Connor, Jianmin Zhang, James L. Drewniak, Mauro Lai, Antonio Orlandi, Giulio Antonini, Albert E. Ruehli Aug 2004

Comparison Of Via Equivalent Circuit Model Accuracy Using Quasi-Static And Full-Wave Approaches, Bruce Archambeault, Samuel R. Connor, Jianmin Zhang, James L. Drewniak, Mauro Lai, Antonio Orlandi, Giulio Antonini, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

The EMC and signal integrity impact of printed circuit board (PCB) trace discontinuities, such as vias, where the signal is transitioned from one layer to another in the PCB stackup, have become significant recently with the use of very high speed signals in today''s systems. If these discontinuities are ignored, significant distortion of the high speed signal can occur, and in many cases, cause data errors. A fast and accurate technique to include the effect of via discontinuities in the typical design process is needed to ensure this distortion is considered if significant. Therefore, a simple equivalent circuit for the …

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Comparison Of Water And Saltwater Movement In Mortar Based On A Semiempirical Electromagnetic Model, Shanup Peer, R. Zoughi Aug 2004

Comparison Of Water And Saltwater Movement In Mortar Based On A Semiempirical Electromagnetic Model, Shanup Peer, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The presence of chloride ions in steel-reinforced structures leads to the corrosion of the reinforcement thus compromising the integrity and strength of the structure. Thus, it is of great interest to nondestructively detect and evaluate free chloride content in concrete. To this end, an investigation was initiated where two mortar cubes were soaked in distilled water and saltwater solutions, respectively. Their temporal microwave reflection properties were measured using open-ended rectangular waveguides on a daily basis for three cycles, each lasting 35 days. Subsequently, a semiempirical electromagnetic model was developed to simulate the reflection properties of the cubes. The outcome of …

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Representation Of Permittivity For Multiphase Dielectric Mixtures In Fdtd Modeling, Marina Koledintseva, J. Wu, H. Zhang, James L. Drewniak, Konstantin Rozanov Aug 2004

Representation Of Permittivity For Multiphase Dielectric Mixtures In Fdtd Modeling, Marina Koledintseva, J. Wu, H. Zhang, James L. Drewniak, Konstantin Rozanov

Electrical and Computer Engineering Faculty Research & Creative Works

A simple method of approximating frequency characteristics of composites in a form convenient for time-domain numerical modeling is proposed. The frequency characteristics can be obtained from experiment or calculations based on the Maxwell Garnett mixing formalism. The resultant frequency characteristic might be of a complex shape corresponding to a combination of a number of absorption peaks. The approximation is made by a series of Debye-like terms using a genetic algorithm (GA). This leads to the necessity of taking a number of terms in the approximating series. Every term corresponds to its pole, i.e., the frequency where the maximum loss occurs. …

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Static And Quasi-Dynamic Load Balancing In Parallel Fdtd Codes For Signal Integrity, Power Integrity, And Packaging Applications, Sarah A. Seguin, Michael A. Cracraft, James L. Drewniak Aug 2004

Static And Quasi-Dynamic Load Balancing In Parallel Fdtd Codes For Signal Integrity, Power Integrity, And Packaging Applications, Sarah A. Seguin, Michael A. Cracraft, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

The Finite-Difference Time-Domain (FDTD) method is a robust technique for calculating electromagnetic fields, but practical problems, involving complex or large geometries, can require a long time to calculate on any one single-processor computer. One computer with many processors or many single-processor computers can reduce the computation time. However, some FDTD cell types, e.g., PML cells, require more computation time than others. Thus, the size and shape of the individual process allocations can significantly influence the computation time. This paper addresses these load balancing issues with static and quasi-dynamic approaches. The Message-Passing Interface (MPI) library is applied to a three-dimensional (3D) …

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Validation Of Equivalent Circuits Extracted From S-Parameter Data For Eye-Pattern Evaluation, Giuseppe Selli, Mauro Lai, Shaofeng Luan, James L. Drewniak, Richard E. Dubroff, Jun Fan, James L. Knighten, Norman W. Smith, Giulio Antonini, Antonio Orlandi, Bruce Archambeault, Samuel R. Connor Aug 2004

Validation Of Equivalent Circuits Extracted From S-Parameter Data For Eye-Pattern Evaluation, Giuseppe Selli, Mauro Lai, Shaofeng Luan, James L. Drewniak, Richard E. Dubroff, Jun Fan, James L. Knighten, Norman W. Smith, Giulio Antonini, Antonio Orlandi, Bruce Archambeault, Samuel R. Connor

Electrical and Computer Engineering Faculty Research & Creative Works

S-parameter circuit model extraction is usually characterized by a trade off between accuracy and complexity. Trading one feature for another may or may not affect the goodness of the reconstructed S-parameter data, which are obtained from frequency domain simulations of the models extracted. However, the ultimate test for the validity of these equivalent circuit representations should be left to eye-diagram simulations, which provide useful insights, from an SI point of view, about the degradation of the signal, as it travels through the system. Physics based simplication procedures can be used to tune the models and achieve less complexity, whereas the …

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A Circuit Approach To Model Narrow Slot Structures In A Power Bus, Lin Zhang, Ray Alexander, Richard E. Dubroff, James L. Drewniak, James L. Knighten, Norman W. Smith, Bruce Archambeault, Samuel R. Connor, Jun Fan Aug 2004

A Circuit Approach To Model Narrow Slot Structures In A Power Bus, Lin Zhang, Ray Alexander, Richard E. Dubroff, James L. Drewniak, James L. Knighten, Norman W. Smith, Bruce Archambeault, Samuel R. Connor, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

A coupled transmission line model for narrow slot structures in DC power planes is proposed. This approach, combined with SPICE-based cavity models and a segmentation method, provides an easy and fast way to model relatively complex structures of power planes with narrow slots often used for isolation purposes. This approach is used to achieve isolation using gapping. The cavity model formulations for rectangular and isosceles right triangular segments are reviewed. The rationale of modeling the narrow slot as a three-conductor transmission line is described. The modeling results are shown and compared with the output of a full wave simulation tool, …

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A Method Of Including Switching Loss In Electro-Thermal Simulations, Jonathan W. Kimball Aug 2004

A Method Of Including Switching Loss In Electro-Thermal Simulations, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

Often, power electronics systems are simulated with ideal switching elements, perhaps augmented with conduction loss models. A behavioral model is proposed that also includes switching loss and is independent of switching frequency. Therefore, it is suitable for variable frequency control methods, including hysteresis, delta modulation, and random PWM. Models have been realized in Dymola using voltage-controlled voltage sources, current sources, logic, and additional ideal switches. Thermal ports are included to facilitate electro-thermal simulation. A method for parameter extraction is demonstrated using experimental data from standard PWM.

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