Methods for Improving the Design of Experiments Outcome in an ME Curriculum

2006 ◽  
Author(s):  
Timothy C. Scott
Keyword(s):  
Design Of Experiments ◽  
Electronics Cooling ◽  
Thermal Design ◽  
Experiment Planning ◽  
Design Activity ◽  
Technical Literature ◽  
Skill Levels ◽  
Actual Design ◽  
Sufficient Degree ◽  
Student Skill

To do a design of experiments project with a sufficient degree of realism can require a large block of class time. It would be valuable for the students to practice uncertainty analysis, selection of instruments, experiment planning, and application of engineering analysis. It would also be useful for them to learn about test codes and standards, to examine descriptions of similar test rigs found in the technical literature, and to operate within constraints on time, materials and fabrication costs. Time and student skill levels limit the number of these "ideals" that can be achieved, and compromises have to be made. The hope is that these limitations will not cause the project to degenerate to the "design without much analysis the night before the project is due" mentality that many students equate with "design" This paper describes methods for improving the "design of experiments" outcome in the ME curriculum. The design of a rig for testing electronics cooling heat sinks is the project. Activities in several prerequisite courses are coordinated to provide supporting background knowledge. A heat sink thermal design project in the co-requisite heat transfer course is linked to the design of experiments project. These efforts allow more time for the actual design activity. Several techniques for bringing realistic constraints into the project and for improving the efficiency of some traditionally time consuming activities are presented. Instead of simplifying the objective, students are given more assistance in overcoming the problems that they are least able to solve due to their inexperience. In this way, the project maintains a higher level of realism.

Thermal-Structural Performance of Orthotropic Pin Fin in Electronics Cooling Applications

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
A. F. M. Arif ◽  
Syed M. Zubair ◽  
S. Pashah
Keyword(s):  
Heat Sink ◽  
Structural Response ◽  
Electronics Cooling ◽  
Base Plate ◽  
Thermal Design ◽  
Heat Flow Rate ◽  
Thermal Interface ◽  
Conductive Composites ◽  
Thermally Conductive ◽  
As Stress

Thermally conductive composites as compared to metals have reduced density, decreased oxidation, and improved chemical resistance, as well as adjustable properties to fit a given application. However, there are several challenges that need to be addressed before they can be successfully implemented in heat sink design. The interface between the device and heat sink is an important factor in the thermal design of microelectronics cooling. Depending on the thermal interface conditions and material properties, the contact pressure and thermal stress level can attain undesirable values. In this paper, we investigate the effect of thermal interface between the fin and base plate on thermal-structural behavior of heat sinks. A coupled-field (thermal-structural) analysis using finite element method is performed to predict temperature as well as stress fields in the interface region. In addition temperature and heat flow rate predictions are supported through analytical results. effect of various interface geometrical (such as slot-depth, axial-gap, and radial-gap) and contact properties (such as air gap with surface roughness and gaps filled with interface material) on the resulting thermal-structural response is investigated with respect to four interface materials combinations, and it is found that the thermal performance is most sensitive to the slot-depth compared to any other parameter.

Distance Education: Applications in a Masters and Doctoral Program

1997 ◽  
Vol 25 (3) ◽  
pp. 249-271 ◽  
Author(s):  
Lois Ann Hesser ◽  
George Kontos
Keyword(s):  
Electronic Mail ◽  
Doctoral Program ◽  
Work Place ◽  
Compressed Video ◽  
Electronic Library ◽  
Skill Levels ◽  
Electronic Classroom ◽  
Bulletin Boards ◽  
Student Skill ◽  
Study Student

This article examines two graduate programs, one masters and one doctoral, that rely heavily on technological delivery systems. These systems include the use of audiobridge, videotapes, electronic mail, and compressed video. In addition, the programs utilize electronic library access, bulletin boards, and a special tool that was developed in-house, the Electronic Classroom. Included is a survey of “National Cluster” students in the doctoral program. The survey was used to assess the influence that technology, especially telecommunications, has had on the students' ability to complete their course of study, their career, and/or work status, and their personal interaction with friends and colleagues. Preliminary analysis of the survey data indicate that the instruction that these students received enabled them to perform in a positive way throughout their study. Student skill levels were increased, and the carryover to their work place was evident.

PIV Measurements of the Effects of Geometric Scale on Electronics Cooling Axial Fan Flow

2007 ◽  
Author(s):  
Ronan Grimes ◽  
David Quin ◽  
Edmond Walsh ◽  
Jeff Punch
Keyword(s):  
Velocity Distribution ◽  
Axial Flow ◽  
Electronics Cooling ◽  
Thermal Design ◽  
Small Scale ◽  
Axial Fan ◽  
Flow Angle ◽  
Piv Measurements ◽  
Cooling Fan ◽  
Macro Scale

The emergence of highly functional portable electronic systems in recent times means that passive dissipation of heat in these devices may not be an option in the near future. Micro fan technology is currently being developed to address this emerging need. Past investigations by the current authors indicate that the reduction of scale of conventional electronics cooling fan design to the mini scale does not excessively impair the bulk pressure flow performance of the fan. However, the detailed velocity distribution at the outlet of mini scale axial flow fans is unknown, and so effective thermal design in systems which use mini scale fans may be difficult, as the designer does not know the path taken by the flow emerging from the fan. To address this issue, this paper presents PIV measurements performed at the outlet of a series of geometrically similar axial flow fans, whose diameters range from 120 to 6mm, and whose design is based on that of a commercially available macro scale electronics cooling fan. The measurements show that as fan scale is reduced, there is a significant change in the fan outlet velocity distribution, and a large increase in the outlet radial flow angle. As a result, a designer using a small scale axial flow fan must be aware that the region downstream of the fan, where one would normally expect high velocity flow, will in fact be uncooled. Therefore, components should be mounted radially downstream of the fan, where highest air velocities are shown to exist.

Disability Identification and Educational Accommodations: Lessons From the 2019 Admissions Scandal

2020 ◽  
Vol 49 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Benjamin J. Lovett
Keyword(s):  
Learning Disabilities ◽  
Test Scores ◽  
Diagnostic Tests ◽  
Objective Data ◽  
Skill Levels ◽  
Identification Methods ◽  
Unequal Treatment ◽  
Student Skill ◽  
Disability Identification ◽  
Educational Accommodations

A recent, widely publicized scandal involved students who obtained fraudulent diagnoses of learning disabilities in an effort to get accommodations on college admissions tests. Although the exact circumstances of the scandal are unusual, the methods used to obtain diagnoses and accommodations illustrate widespread problems with current policies. These problems include certain disability identification methods that overemphasize performance on diagnostic tests, a lack of attention to the unfair advantages that unwarranted accommodations can provide, and a lack of commonly used guidelines for making accommodations decisions based on credible, objective data. The scandal was a rare consequence of these problems, but far more frequent consequences involve unequal treatment of students from different backgrounds and test scores that fail to reflect actual student skill levels.

Thermal Analysis of Cold Plate for Motor Controller Based on Fluent

2012 ◽  
Vol 249-250 ◽  
pp. 691-695
Author(s):  
Gui Lin Lin ◽  
Guo Qing Xu ◽  
Wei Min Li ◽  
Bin Bin Liu
Keyword(s):  
Electric Vehicle ◽  
Optimization Design ◽  
Controller Design ◽  
Electronics Cooling ◽  
Thermal Design ◽  
High Heat Flux ◽  
Air Cooling ◽  
Material Base ◽  
Cold Plate ◽  
Motor Controller

Electronics cooling research has been largely focused on high heat flux removal from computer chips in the recent years. However, the equally important field of high-power electronic devices has been experiencing a major paradigm shift from air cooling to liquid cooling over the last decade. For example, multiple insulated-gate bipolar transistors (IGBT) used in a power drive for motor used in electric vehicle. Motor drive system plays an important impact on electric vehicle’ performance, so thermal design should be considered in the early stages during the motor controller design and layout of the devices. In this paper, a new type of water-cooled cold plate for motor controller was designed, and its cooling ability was analyzed by using different material base on Fluent. The results provide reference on the optimization design of cold plate.

Tolerance Allocation Using Design of Experiments

2015 ◽  
Vol 760 ◽  
pp. 45-50
Author(s):  
Felicia Veronica Banciu ◽  
Ion Grozav ◽  
Cristian Gheorge Turc
Keyword(s):  
Design Of Experiments ◽  
Practical Problem ◽  
Quality Characteristics ◽  
Tolerance Allocation ◽  
Quality Characteristic ◽  
Design Activity ◽  
Tolerance Design ◽  
Mathematical Function ◽  
Optimal Parameters ◽  
High Quality

Tolerance design plays a very important in any manufacturing process because this activity directly influences products cost and quality. In design activity the designer solve the quality problems selecting tight tolerances for components but this generates cost increasing. The practical problem is to assure the high quality characteristics using the maximum tolerances for components that influence them. The paper’s aim is to find optimal parameters setting which assure the desire value of quality characteristics using the DoE (Design of Experiments), and to find a mathematical model and a respective quality characteristic function of the parameters that it was influenced. Using the mathematical function, by imposing the desired tolerance for quality characteristic, it will be allocated the optimal tolerance for components. This tolerance allocation will be verified using Monte-Carlo method.

Fixed Vane Stator Development for Axial Fan Performance Improvement in Electronics Cooling

2007 ◽  
Author(s):  
Gavin D. Stanley
Keyword(s):  
Design Of Experiments ◽  
Acoustic Noise ◽  
Dynamic Pressure ◽  
Electronics Cooling ◽  
Leading Edge ◽  
Cfd Modeling ◽  
Axial Fan ◽  
Development Method ◽  
Stator Vane ◽  
Axial Fans

An analysis and development method for augmenting flow and pressure performance of electronic cooling axial fans using a fixed vane stator is established using classical hand calculations, 2-dimensional (2D) Computational Fluid Dynamics (CFD) analysis, data from a design of experiments, and 3-dimensional (3D) CFD modeling. Where the size of electronic enclosures may disallow an increase in diameter of axial fans but allow for an increase in depth; a fixed vane stator is implemented to recapture lost dynamic pressure associated with swirl and radial flow vectors from the axial fan blades thus augmenting the pressure/flow curve of the unit. Stator blade effectiveness is evaluated and optimized first using data associated with National Advisory Committee for Aeronautics (NACA) airfoil shapes and then using 2-dimensional (2D) CFD analyses on both the impeller and stator blades. CFD modeling approaches and solving methods are discussed. A Design of Experiments (DOE) is utilized to verify and optimize the performance of the stator vanes and identifies the effectiveness of the stator vane angle, curvature of the stator leading edge, and number of stator vanes. At a constant back pressure the best performing DOE geometry delivered a 22% improvement in flow at constant electrical power input and a 41% improvement in flow at constant acoustic noise. This result was confirmed using a 3D CFD modeling. This analysis and development method provides a good baseline for evaluating and choosing proper stator vane geometries for flow improvement in axial fans.

Thermal Resistance of Particle Laden Polymeric Thermal Interface Materials

2003 ◽  
Author(s):  
Ravi S. Prasher ◽  
Jim Shipley ◽  
Suzana Prstic ◽  
Paul Koning ◽  
Jin-Lin Wang
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Volume Fraction ◽  
Applied Pressure ◽  
Electronics Cooling ◽  
Thermal Design ◽  
Thermal Interface Materials ◽  
Particle Volume ◽  
Thermal Interface ◽  
Interface Materials

Particle laden polymers are one of the most prominent thermal interface materials (TIM) used in electronics cooling. Most of the research has primarily dealt with the understanding of the thermal conductivity of these types of TIMs. For thermal design, reduction of the thermal resistance is the end goal. Thermal resistance is not only dependent on the thermal conductivity, but also on the bond line thickness (BLT) of these TIMs. It is not clear which material property(s) of these particle laden TIMs affects the BLT and eventually the thermal resistance. This paper introduces a rheology based semi-empirical model for the prediction of the BLT of these TIMs. BLT depends on the yield stress of the particle laden polymer and the applied pressure. The BLT model combined with the thermal conductivity model can be used for modeling the thermal resistance of these TIMs for factors such as particle volume faction, particle shape, base polymer viscosity, etc. This paper shows that there exists an optimal filler volume fraction at which thermal resistance is minimum. Finally this paper develops design rules for the optimization of thermal resistance for particle laden TIMs.

Teaching Badminton Based on Student Skill Levels

Strategies ◽  
2009 ◽  
Vol 22 (6) ◽  
pp. 14-18 ◽  
Author(s):  
Jianyu Wang ◽  
Jeff Moffit
Keyword(s):  
Skill Levels ◽  
Student Skill
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