Engineering Commons^™

Bass Code Development, Scott Sawyer

Mechanical Engineering Faculty Research

The BASS computational aeroacoustic code solves the fully nonlinear Euler equations in the time domain in two-dimensions. The acoustic response of the stator is determined simultaneously for the first three harmonics of the convected vortical gust of the rotor. The spatial mode generation, propagation and decay characteristics are predicted by assuming the acoustic field away from the stator can be represented as a uniform flow with small harmonic perturbations superimposed. The computed field is then decomposed using a joint temporal-spatial transform to determine the wave amplitudes as a function of rotor harmonic and spatial mode order. This report details the …

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.

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, …

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 …

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 …

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 …

Wavelenght-Dispersive X-Ray Flourescence Accuration, H. Widyatmoko

Makara Journal of Technology

Wavelenght–Dispersive X-Ray Flourescence Accuration. X-Fuorescence spectrometry is a method, which is increasingly applied in the geochemical analysis. X-Fuorescence spectrometry is classified under two categories – WDXRF (wavelenght – dispersive X-ray fluorescence spectrometer) and EDXRF (energy-dispersive X – ray fluorescence spectrometer). WDXRF can be configured as a sequential spectrometer , a simultaneous spectrometer or a hibrid instrument, which combines the advantages of the simultaneous and sequential spectrometers into one instrument. Each instrument is different in some characteristics, and each has applications for which it is specifically suited. In this investigation sequential spectrometer PW 1450 was used to analyze the major, minor …

Secondary Flow Experimental Study For Axial Compressor Cascade Strong Stagger With And Without Tip- Clearance: Static Pressure Distribution On Blade Surface, Syamsuri Syamsuri

Makara Journal of Technology

Secondary Flow Experimental Study for Axial Compressor Cascade Strong Stagger With and Without Tip- Clearance: Static Pressure Distribution on Blade Surface. The performance of blade cascade is influenced by the growth and boundary layer’s separation along blade surface and endwall (casing and hub). The secondary flow which happens near hub and casing compressors is three dimentional flow separation phenomenon comes from interaction blade boundary layer with casing and hub boundary layers in the compressor. The secondary flow causes secondary losses, blockage effect, and turning angle (deflection) distribution along blade span. The result of the research shows that the increase of …

Effect Of Photoperiodicity On Co2 Fixation By Chlorella Vulgaris Buitenzorg In Bubble Column Photobioreactor For Food Supplement Production, Anondho Wijanarko, Dianursanti Dianursanti, Arief Budi Witarto, Roekmijati Widaningroem Soemantojo

Makara Journal of Technology

To reduce the level of CO2 content in air, effort on converting CO2 to useful products is required. One of the alternatives includes CO2 fixation to produce biomass using Chlorella vulgaris Buitenzorg. Chlorella vulgaris Buitenzorg is applied for production of food supplement. Chlorella vulgaris Buitenzorg is also easy to handle due to its superior adaptation. Currently, Chlorella vulgaris Buitenzorg has been analyzed by some experts for its cellular composition, its ability to produce high quality biomass and the content of essential nutrition. A series of experiments was conducted by culturing Chlorella vulgaris Buitenzorg using Beneck medium in bubbling column photobioreactor. …

Synthesize Of Emulsion Polymer Latex For Sub-Grade Cbr Improvement In The Road Construction, Keba Moto, V. Julian, Syamsudin Syamsudin, T. A. Wiradi, S. R. Wijaya

Makara Journal of Technology

Synthesize of emulsion polymer latex for sub-grade CBR improvement in the road construction. Latex polymer for California Bearing Ratio (CBR) enhancement in sub-grade soil of road building has been prepared by emulsion polymerizations technique. The prepared polymer then characterize by Fourier Transform Infrared (FTIR). For application purpose, CBR test was done to the compacted polymer added-soil. The CBR test is done also for both soaked and unsoaked samples. It is found that our latex polymer is better then other imported latex polymer. For the latex polymer, which is design to have Temperatur glass (Tg) around 9.8-19.6o, indicating the formation of …

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

CCFSS Technical Bulletins (1993 - 2020)

No abstract provided.

Assessing Six Residential Ventilation Techniques In Hot And Humid Climates, Florida Solar Energy Center, Neil Moyer

FSEC Energy Research Center®

The addition of mechanical ventilation air to "tight" homes in hot and humid climates may adversely impact health, building durability, comfort and energy use by raising indoor humidity levels (RH) above 50%. High indoor humidity has been linked to microbial growth, building material decay, discomfort, and increased energy use (Moyer, et al, 2001). High indoor humidity in "tight" homes with mechanical ventilation has been documented in various Building America projects in hot humid locations (Rudd 2003).

The research described here quantifies the energy use, and humidity impacts of six mechanical ventilation strategies installed serially in a new, Energy Star Manufactured …

Generating Properties For Runtime Monitoring From Software Specification Patterns, Oscar Mondragon, Ann Q. Gates, Oleg Sokolsky

Departmental Technical Reports (CS)

The paper presents an approach to support run-time verification of software systems that combines two existing tools, Prospec and Java-MaC, into a single framework. Prospec can be used to clarify natural language specifications for sequential, concurrent, and nondeterministic behavior. In addition, the tool assists the user in reading, writing, and understanding formal specifications through the use of property patterns and visual abstractions. Currently, Prospec automatically generates a specification written in Future Interval Logic (FIL). The goal is to automate the generation of MEDL formulas that can be used by the Java-MaC tool to check run-time compliance of system execution to …

Non-Lexical Conversational Sounds In American English, Nigel Ward

Departmental Technical Reports (CS)

This article analyzes the non-lexical conversational sounds (conversational grunts) of English, including such items as uh-huh, un-hn, um, mm, and oh, based primarily on examination of a few hundred occurrences in a corpus of conversations. The data includes extensive phonetic variation, suggesting that these items are best explained, not as fixed words, but as dynamic creations. In particular, the vast majority of these items can be generated by a simple model consisting of 10 component sounds and 2 combining rules. Moreover, each of these component sounds seems to bear some meaning or function which is fairly constant across grunts and …

Geotechnical Reconnaissance Of The 2002 Denali Fault, Alaska, Earthquake, Robert E. Kayen, Eric Thompson, Diane Minasian, Robb E.S. Moss, Brian D. Collins, Nicholas Sitar, Douglas Dreger, Gary Carver

Civil and Environmental Engineering

The 2002 M7.9 Denali fault earthquake resulted in 340 km of ruptures along three separate faults, causing widespread liquefaction in the fluvial deposits of the alpine valleys of the Alaska Range and eastern lowlands of the Tanana River. Areas affected by liquefaction are largely confined to Holocene alluvial deposits, man-made embankments, and backfills. Liquefaction damage, sparse surrounding the fault rupture in the western region, was abundant and severe on the eastern rivers: the Robertson, Slana, Tok, Chisana, Nabesna and Tanana Rivers. Synthetic seismograms from a kinematic source model suggest that the eastern region of the rupture zone had elevated strong-motion …

Wire Bonding Challenges In Optoelectronics Packaging, Jianbiao Pan, Patrice Fraud

Industrial and Manufacturing Engineering

Wire bonding has been used in integrated circuit (IC) packaging for many years. However, there are many challenges in wire bonding for optoelectronics packaging. These challenges include bonding on sensitive devices, bonding over cavity, bonding over cantilevel leads and bonding temperature limitations. The optoelectronics package design brings another challenge, which requires wire bonding to have deep access capability. In this paper, the wire bonding technologies are reviewed and ball bonding and wedge bonding are compared. The variables that affect the wire bonding process are then discussed. Finally, the challenges of wire bonding in optoelectronics packaging are presented in detail.

An Intelligent Parameter Varying (Ipv) Approach For Non-Linear System Identification Of Base Excited Structures, Soheil Saadat, Gregory D. Buckner, Tadatoshi Furukawa, Mohammad N. Noori

Office of the Dean (CENG) Scholarship

Health monitoring and damage detection strategies for base-excited structures typically rely on accurate models of the system dynamics. Restoring forces in these structures can exhibit highly non-linear characteristics, thus accurate non-linear system identification is critical. Parametric system identification approaches are commonly used, but require a priori knowledge of restoring force characteristics. Non-parametric approaches do not require this a priori information, but they typically lack direct associations between the model and the system dynamics, providing limited utility for health monitoring and damage detection. In this paper a novel system identification approach, the intelligent parameter varying (IPV) method, is used to identify …

Evaluation Of A Modified Mpa Procedure Assuming Higher Modes As Elastic To Estimate Seismic Demands, Anil K. Chopra, Rakesh K. Goel, Chatpan Chintanapakdee

Civil and Environmental Engineering

The modal pushover analysis (MPA) procedure, which includes the contributions of all significant modes of vibration, estimates seismic demands much more accurately than current pushover procedures used in structural engineering practice. Outlined in this paper is a modified MPA (MMPA) procedure wherein the response contributions of higher vibration modes are computed by assuming the building to be linearly elastic, thus reducing the computational effort. After outlining such a modified procedure, its accuracy is evaluated for a variety of frame buildings and ground motion ensembles. Although it is not necessarily more accurate than the MPA procedure, the MMPA procedure is an …

Calibration, Verification And Sensitivity Analysis Of The Hec-Hms Hydrologic Model, Juraj Cunderlik, Slobodan P. Simonovic

Water Resources Research Report

The main objective of this report is to describe the calibration, verification, and sensitivity analysis of the United States Army Corps of Engineers (USACE) Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) on the data from the Upper Thames River basin (UTRb) study area. The HEC-HMS model was chosen to be the most appropriate hydrologic modeling tool for achieving the goals set in the Canadian Foundation for Climatic and Atmospheric Sciences (CFCAS) funded project “Assessment of Water Resources Risk and Vulnerability to Changing Climatic Conditions” (“project” hereafter), (Cunderlik and Simonovic, 2003). The calibration, verification and sensitivity analysis of the HMS model …

A Study On The Correspondence Of Common-Mode Current In Electromagnetic Radiation From A Pcb With A Guard-Band, Yoshiki Kayano, Motoshi Tanaka, Hiroshi Inoue, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A PCB, in which the ground plane has a finite width and the trace has unbalanced positioning, can result in common-mode (CM) radiation. So far, CM current which is generated by the unbalance of a trace and ground plane has been investigated by experiment and numerical method. It was clarified that CM current is well explained the radiation from PCB up to a few hundred megahertz, and addition of a guard band geometry, which is well connected to the ground plane, can be effective in suppressing the CM current. But it is seemed to be insufficient description for the phenomena …

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

CCFSS Newsletters (1999 - 2008)

No abstract provided.

Acuta Enews August 2004, Vol. 33, No. 8

ACUTA Newsletters

In This lssue

ACUTA Board & Committee Changes.................. Tamaro Closs, Georgetown Univ., ACUTA President-Elect

Tech Talk........................... Kevin Tanzillo, Dux Public Relations

LAN Cabling-When Too Much Bandwidth ls Never Enough . Aref Baddar, NextGen/ General Cable

DC Update..................... Whitney Johnson, Retired, Northern Michigan Univ.

Meet Amy White, ACUTAs New Accounting & Administrative Assistant

Welcome New Members

Feedback Linearization Based Power System Stabilizer Design With Control Limits, Wenxin Liu, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In power system controls, simplified analytical models are used to represent the dynamics of power system and controller designs are not rigorous with no stability analysis. One reason is because the power systems are complex nonlinear systems which pose difficulty for analysis. This paper presents a feedback linearization based power system stabilizer design for a single machine infinite bus power system. Since practical operating conditions require the magnitude of control signal to be within certain limits, the stability of the control system under control limits is also analyzed. Simulation results under different kinds of operating conditions show that the controller …

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.

Series-Parallel Approaches And Clamp Methods For Extreme Dynamic Response With Advanced Digital Loads, Philip T. Krein, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

The series-input parallel-output dc-dc converter combination provides inherent sharing among the converters. With conventional controls, however, this sharing is unstable. Recent literature work proposes complicated feedback loops to correct the problem, at the cost of dynamic performance. This paper shows that a simple sensorless current mode control stabilizes sharing with fast dynamics suitable for advanced digital loads. With this control in place, a "super-matched" current sharing control emerges. Sharing occurs through transients, limited only by the energy limits of the converters. The control approach has considerable promise for high-performance voltage regulator modules. For even faster response, clamping techniques are proposed.

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 …

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 …

Inspection And Evaluation Of A Bridge Deck Partially Reinforced With Gfrp Rebars, Issam E. Harik, P. Alagusundaramoorthy, V. Gupta, Chris Hill, Choo Ching Chiaw

Kentucky Transportation Center Research Report

The corrosion of steel can be a significant problem in bridge decks in which the reinforcing and prestressing steel are accessible to deicing salts and combinations of moisture, temperature and chlorides through cracks, leading to concrete deterioration and loss of serviceability. Fiber Reinforced Polymer (FRP) rebars have emerged as one alternative to steel reinforcement in corrosive environments.

The objective of this study is to evaluate the cracks formed on a bridge deck that is partially reinforced with glass fiber reinforced polymer (GFRP) rebars. The bridge constructed in 1997 is in Bourbon County, KY, on US460 over the Rogers' Creek. Its …

Developing An Intelligent Transportation Systems (Its) Architecture For The Kipda Region, Joseph D. Crabtree, Jennifer R. Walton

Kentucky Transportation Center Research Report

This report describes the development of a regional Intelligent Transportation Systems (ITS) Architecture for the five-county urban area under the auspices of the Kentuckiana Regional Planning and Development Agency (KIPDA). The architecture development process included the following steps: (1) Preliminary Architecture Work; (2) Inventory of Existing and Planned Projects; (3) Assessment of Regional Needs; (4) Development of Preliminary Architecture; (5) Review and Revision of Architecture; and (6) Delivery of Final Architecture and Documentation. Principal tools used in the development included the National ITS Architecture (version 4.0) and the Turbo Architecture software (version 2.0). Deliverables included the architecture database (created using …

Evaluation Of The Service Performance Of Bridge Components, Theodore Hopwood Ii, Robert Brown

Kentucky Transportation Center Research Report

This study was initiated to provide review of common bridges to determine the performance of their components. Seven bridge types were selected that constituted 85 % of the Kentucky Transportation Cabinet (KYTC) bridge inventory. 319 bridges were inspected by Kentucky Transportation Cabinet (KTC) researchers, representing 5 about % of those bridges. Common details/components were identified and evaluated including features of interest to the KYTC Study Advisory Committee. In addition to those findings, KTC researchers evaluated KYTC National Bridge Inventory reports and maintenance needs forms for the same bridges.

Design modifications/material changes were recommended to improve performance of new bridges. Additionally, …