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Articles 691 - 720 of 1342

Full-Text Articles in Mechanical Engineering

A Methodology For The Extraction Of Design Principles For Unfamiliar Markets, Robert D. Campbell Apr 2013

A Methodology For The Extraction Of Design Principles For Unfamiliar Markets, Robert D. Campbell

Theses and Dissertations

Successful product design focuses on design principles that are relevant to a target market. Consequently, the better these principles are understood and used, the higher the likelihood that resulting products will be well-received in that market. This thesis presents a method for extracting market-specific design principles for any market. The method employs user/designer-described characteristics of products within a market to extract the design principles specific to that market. The method generalizes the product characteristics, seeks to discover design decisions that could have resulted in those characteristics, and then extracts the underlying design principles. To demonstrate the ability of the method …

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Fully Compliant Mechanisms For Bearing Subtraction In Robotics And Space Applications, Ezekiel G. Merriam Apr 2013

Fully Compliant Mechanisms For Bearing Subtraction In Robotics And Space Applications, Ezekiel G. Merriam

Theses and Dissertations

Robotics and space applications represent areas where compliant mechanisms can continue to make a significant impact by reducing costs and weight while improving performance. Because of the nature of these applications, a common need is for bearing replacement mechanisms, or mechanisms that perform the function of a bearing without the complexity and failure modes associated with bearings. Static balancing is a design strategy that attempts to reduce the actuation effort of a mechanism, and has been applied to compliant mechanisms in some applications. Monolithic construction, especially by means of 3D printing technology, is a strategy whereby the mechanism links and …

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Influence Of Tissue Stiffness Asymmetry On Human Vocal Fold Vibration, Kimberly Stevens, Dr. Scott Thomson Apr 2013

Influence Of Tissue Stiffness Asymmetry On Human Vocal Fold Vibration, Kimberly Stevens, Dr. Scott Thomson

Journal of Undergraduate Research

The flow-induced vibration of the human vocal folds produces the sound for voiced speech and singing. The vocal folds consist of two folds of tissue, one on each side of the larynx, that are nominally symmetric in terms of shape, composition, and stiffness. However, several voice disorders, including vocal fold scarring and inflammation, cause severe asymmetry in vocal fold tissue properties. The asymmetry can lead to irregular vocal fold vibration and subsequent decrease in voice quality. A more accurate understanding of the effect of vocal fold asymmetry can aid in the development of improved clinical care of the human voice. …

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Measurement Of Wing Loads During Flapping Flight, Ryan Anderson, Dr. Mark Colton Apr 2013

Measurement Of Wing Loads During Flapping Flight, Ryan Anderson, Dr. Mark Colton

Journal of Undergraduate Research

Ongoing research at BYU with the Flapping Flight Research Group (FFRG) is aimed at uncovering the physics behind flapping flight. Discoveries in this field could produce new aircraft designs and technolo- gies, as well as broaden our understanding of natural phenomena. One ambition of the FFRG is to quanti- fy (as determined by lift and thrust) wing trajectories followed during flight. To achieve this quantifica- tion, a precise sensor is necessary to record the lift and thrust produced during each flap.

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Assessing The Impact Of The Approximations Used In The Development Of The Pulsed Laser Method For Measuring Thermal Diffusivity, Trevor Terrill, Dr. Matthew Jones Apr 2013

Assessing The Impact Of The Approximations Used In The Development Of The Pulsed Laser Method For Measuring Thermal Diffusivity, Trevor Terrill, Dr. Matthew Jones

Journal of Undergraduate Research

The purpose of this project was to conduct a rigorous investigation of each of the approximations made in the development of the pulsed laser method for measuring the thermal diffusivity. Thermal conductivity is an important engineering parameter, but measuring it directly is difficult. In common engineering practice, the thermal diffusivity, specific heat, and density are measured, and the thermal conductivity is calculated from these properties. The pulsed laser or flash method is commonly employed to measure the thermal diffusivity, but it contains many restrictive approximations that are difficult to satisfy in practice. This project investigated the significance of each of …

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Investigation And Development Of Of Pyrometer Coating, Weston Baxter, Dr. Dale Tree Apr 2013

Investigation And Development Of Of Pyrometer Coating, Weston Baxter, Dr. Dale Tree

Journal of Undergraduate Research

This project aimed to produce and test an opaque surface on an optical fiber tip that will survive temperatures up to 3000 K. The optical fiber is to be used to measure flame temperature in oxy-coal and other combustion processes.

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Power Harvesting System For More Efficient, Cleaner Burning Cookstoves, Suman Pokharel, Dr. Matthew Jones Apr 2013

Power Harvesting System For More Efficient, Cleaner Burning Cookstoves, Suman Pokharel, Dr. Matthew Jones

Journal of Undergraduate Research

Each day more than 2 billion people cook using open fires or fires in primitive cook stoves that are fueled with biomass (wood, straw, crop waste, dung, etc…). These fires pollute homes and the environment, leading to serious health problems and contributing to global climate change. Additionally, fuel must be purchased at relatively high prices, or many hours are required to gather sufficient fuel each day. High fuel costs add in the limited financial resources, and collecting for fuel limits time available for education or other economically productive activities.

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Creation Of An Interactive Early-Stage Design Environment, Braden Hancock, Dr. Christopher Mattson Apr 2013

Creation Of An Interactive Early-Stage Design Environment, Braden Hancock, Dr. Christopher Mattson

Journal of Undergraduate Research

In my proposal for an ORCA grant, I provided a plan to assist design engineers in the early stages of the design process. This I proposed to do through the development of a computational environment wherein design engineers could more fully and simply analyze the relationships between the various design objects (variables, constraints, and objectives) that define a multiobjective optimization problem (MOP). Thanks to the opportunity that I received to pursue this research, that technology has been developed and disseminated in the scientific community through two academic journals, two professional conferences, and one student conference.

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Research And Design Of Transtibial Prosthetic Shower Legs, Angelina Schwartz, Dr. Eric Homer Apr 2013

Research And Design Of Transtibial Prosthetic Shower Legs, Angelina Schwartz, Dr. Eric Homer

Journal of Undergraduate Research

The aim of 2ft Prosthetics is to design, test, and distribute low-cost prostheses to below-the-knee amputees in developing countries. To do this, a research and development team focuses on the design and construction of the prosthesis. It is then tested on local amputees by the clinical trials team. During this interaction we gain many insights regarding improvements that can be made to the prosthesis to make it more comfortable, reliable, and versatile. We learned that many high- level prostheses commonly used here in the United States are not designed to be used in wet environments. Amputees must remove it to …

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Solar Powered Airplane: Student Design/Build/Fly Project, Dr. Jerry Bowman Apr 2013

Solar Powered Airplane: Student Design/Build/Fly Project, Dr. Jerry Bowman

Journal of Undergraduate Research

Involve a significant number of students in a multi-semester project with intense technical challenges and a well-defined objective: The creation of a solar powered airplane with the goal of indefinite flight.

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A Multiplicative Extended Kalman Filter For Relative Rotorcraft Navigation, Robert C. Leishman, Timothy W. Mclain Mar 2013

A Multiplicative Extended Kalman Filter For Relative Rotorcraft Navigation, Robert C. Leishman, Timothy W. Mclain

Faculty Publications

In this article we detail the fundamentals of a new approach to GPS-denied navigation for aerial vehicles in confined indoor environments. We depart from the common practice of navigating within a globally referenced map, and instead keep the position and yaw states relative to the current node in the map. The approach combines elements of graph SLAM with a multiplicative extended Kalman filter (MEKF). The filter provides quality state estimates at a fast rate and a graph SLAM algorithm maintains a pose graph. We provide specific details for the relative MEKF. We verify the relative estimation approach with hardware flight …

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Investigations Of Partially Immersed Spinning Spheres In A Liquid Bath And Butterfly Flight, Kenneth Roy Langley Mar 2013

Investigations Of Partially Immersed Spinning Spheres In A Liquid Bath And Butterfly Flight, Kenneth Roy Langley

Theses and Dissertations

This thesis examines two important problems in fluid dynamics: that of a partially immersed sphere spinning in a bath of liquid and the measurement of flow velocities around a free flying butterfly. Although the actual problems are quite different, each problem incorporates many of the same principles and techniques. When a hard-boiled egg spins through a pool of milk on the kitchen counter, the milk rises up the sides of the egg and droplets are ejected. This phenomenon occurs when any partially submerged object whose radius increases upward from the fluid surface (e.g., spheres, inverted cones, rings, etc.), spins in …

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Passive Stiffness Of Coupled Wrist And Forearm Rotations, Will Brandon Drake Mar 2013

Passive Stiffness Of Coupled Wrist And Forearm Rotations, Will Brandon Drake

Theses and Dissertations

The dynamics of wrist rotations are dominated by joint stiffness, which the neuromuscular system must account and compensate for when controlling wrist movements. Because wrist stiffness is anisotropic, movements in some directions require less torque than movements in others, creating opportunities to follow "paths of least resistance." Forearm pronation-supination (PS) can combine with wrist flexion-extension (FE) and radial-ulnar deviation (RUD) to allow the wrist to rotate in directions of least stiffness. Evaluating this hypothesis, and understanding the control of combined wrist and forearm rotations in general, requires a knowledge of the stiffness (the dominant mechanical impedance) encountered during combined wrist …

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Research And Publication Opportunities In Structure Of Materials, Dr. David Fullwood, Dr. Brent Adams, Dr. Chris Mattson Mar 2013

Research And Publication Opportunities In Structure Of Materials, Dr. David Fullwood, Dr. Brent Adams, Dr. Chris Mattson

Journal of Undergraduate Research

The MEG award has been used by our research group as a springboard to launch undergraduates to levels of excellence in academia and the engineering community, and as seed money for research initiatives that will benefit these and future undergraduates. It has been used to leverage significant other funding sources and multiply its effects. Here are some highlights:

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Starch Resin Moisture Level Effect On Injection Molding Processability And Molded Part Mechanical Properties With Pure Starch Resin And Polymer Blends, Jordan M. Ellingson Mar 2013

Starch Resin Moisture Level Effect On Injection Molding Processability And Molded Part Mechanical Properties With Pure Starch Resin And Polymer Blends, Jordan M. Ellingson

Theses and Dissertations

The current and forecasted global consumption of plastic packaging and products through the 21st century combined with the already reported and growing negative impact of plastics on the environment due to plastics being synthesized from nonrenewable resources that do not biodegrade is of serious concern. However, recent advances in starch technology including the development of thermoplastic starch (TPS) materials —polymers that are both renewable and biodegradable—have brought hope to reducing this impact. The mechanical properties of thermoplastic starch have often been improved by blending with synthetic polymers. One issue that arises with blending is volatilization of the melt from moisture …

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Location-Allocation Optimization Of Supply Chain Distribution Networks: A Case Study, Mark Nicholas Helberg Mar 2013

Location-Allocation Optimization Of Supply Chain Distribution Networks: A Case Study, Mark Nicholas Helberg

Theses and Dissertations

The location of distribution centers is an important strategic decision in supply chain design, particularly as it relates to service quality, productivity, and profitability of the firm. There has been extensive research performed on distribution location models which require the use of complex algorithms and assumptions that make use of these models difficult in practice for small and medium enterprises (SMEs) that have limited capital and resources. Studies have also failed to capture and quantify potential business results of using more sophisticated methods. In this study, a deterministic and static location-allocation model is designed using a prototype software tool. The …

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Quantifying The Nonlinear, Anisotropic Material Response Of Spinal Ligaments, Daniel J. Robertson Feb 2013

Quantifying The Nonlinear, Anisotropic Material Response Of Spinal Ligaments, Daniel J. Robertson

Theses and Dissertations

Spinal ligaments may be a significant source of chronic back pain, yet they are often disregarded by the clinical community due to a lack of information with regards to their material response, and innervation characteristics. The purpose of this dissertation was to characterize the material response of spinal ligaments and to review their innervation characteristics.


Review of relevant literature revealed that all of the major spinal ligaments are innervated. They cause painful sensations when irritated and provide reflexive control of the deep spinal musculature. As such, including the neurologic implications of iatrogenic ligament damage in the evaluation of surgical procedures …

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Objectives And Constraints For Wind Turbine Optimization, Andrew Ning, Rick Damiani, Patrick Moriarty Feb 2013

Objectives And Constraints For Wind Turbine Optimization, Andrew Ning, Rick Damiani, Patrick Moriarty

Faculty Publications

Efficient extraction of wind energy is a complex multidisciplinary process. This paper examines common objectives used in wind turbine optimization problems. The focus is not on the specific optimized designs, but rather on understanding when certain objectives and constraints are necessary, and what their limitations are. Maximizing annual energy production, or even using sequential aero/structural optimization, is shown to be significantly suboptimal compared to integrated aero/structural metrics. Minimizing the ratio of turbine mass to annual energy production can be effective for fixed rotor diameter designs, as long as the tower mass is estimated carefully. For variable diameter designs, the predicted …

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Electrochemical Explanation For Asymmetric Electrowetting Response, Mehdi Khodayari, Nathan B. Crane, Alex A. Volinsky Jan 2013

Electrochemical Explanation For Asymmetric Electrowetting Response, Mehdi Khodayari, Nathan B. Crane, Alex A. Volinsky

Faculty Publications

In electrowetting, a droplet/substrate contact angle is modulated by applying a potential difference between the droplet and the substrate. Typically, the droplet potential is changed via an auxiliary electrode dipped in the droplet. Here, it is shown that electrochemical reactions lead to a potential drop on the auxiliary electrode in electrowetting, which degrades the droplet contact angle modulation. The magnitude of this effect depends on the voltage polarity. This problem can be addressed by using a dielectric layer, such as SiO2, which can prevent electrochemical reactions with the electrowetting substrate and the auxiliary electrode.

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Techno- Economic Analysis Of Wastewater Biosolids Gasification, Jason M. Porter, Nick Lumley, Robert Braun, Tzahi Cath, Ana Prietro, Dotti Ramey, Greta Buschmann Jan 2013

Techno- Economic Analysis Of Wastewater Biosolids Gasification, Jason M. Porter, Nick Lumley, Robert Braun, Tzahi Cath, Ana Prietro, Dotti Ramey, Greta Buschmann

Faculty Publications

Wastewater treatment biosolids, commonly referred to as sludge, is a dilute suspension of micro-organisms, noxious organic matter, and mineral species in up to 99% water. Sludge is produced at about 250 mg/L of mixed municipal and light industrial wastewater treated. Management of this process stream can present a financial and environmental challenge for wastewater treatment plants (WWTPs), accounting for up to 15% of plant energy consumption. Operators of small urban WWTPs see the greatest challenge as their operations do not benefit from economies of scale, which permit larger facilities to absorb the costs or footprint of anaerobic digestion. This work …

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Supercritical Co2 Brayton Cycles For Solar-Thermal Energy, Brian D. Iverson, Thomas M. Conboy, James J. Pasch, Alan M. Kruizenga Jan 2013

Supercritical Co2 Brayton Cycles For Solar-Thermal Energy, Brian D. Iverson, Thomas M. Conboy, James J. Pasch, Alan M. Kruizenga

Faculty Publications

Of the mechanisms to improve efficiency for solar-­‐thermal power plants, one of the most effective ways to improve overall efficiency is through power cycle improvements. As increases in operating temperature continue to be pursued, supercritical CO2 Brayton cycles begin to look more attractive despite the development costs of this technology. Further, supercritical CO2 Brayton has application in many areas of power generation beyond that for solar energy alone.

One challenge particular to solar-­‐thermal power generation is the transient nature of the solar resource. This work illustrates the behavior of developmental Brayton turbomachinery in response to a fluctuating thermal input, much …

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Methods For Identifying Acoustic Emissions From The Front Face Of A Small Piezoelectric Blower, Brad K. Solomon Dec 2012

Methods For Identifying Acoustic Emissions From The Front Face Of A Small Piezoelectric Blower, Brad K. Solomon

Theses and Dissertations

This thesis focuses on identifying acoustic noise generating components in piezoelectric blowers through transverse velocity measurements and the development of a numerical fluid model. Piezoelectric ceramics have proven useful for many industries and areas of research involving: high precision actuators, noise control, ultrasonic devices, and many other areas. As of late, a unique adaptation of piezoelectric ceramics is surfacing in the area of pumping and cooling. Air pumps that use these ceramics replace the traditional electric motor, resulting in lower power consumption, less moving parts, constant pressure gradients, lower overall weight, and a low profile. The current drawback of this …

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The Effects Of Freestream Turbulence On Serpentine Diffuser Distortion Patterns, Jesse Scott Johnson Dec 2012

The Effects Of Freestream Turbulence On Serpentine Diffuser Distortion Patterns, Jesse Scott Johnson

Theses and Dissertations

Serpentine diffusers have become a common feature in modern aircraft as they allow for certain benefits that are impossible with a traditional linear configuration. With the benefits, however, come certain disadvantages, namely flow distortions that reduce engine efficiency and decrease engine surge stability margins. These distortions are now being researched comprehensively to determine solutions for mitigating the adverse effects associated with them. This study investigates how varying the freestream turbulence intensity of the flow entering a serpentine diffuser affects the distortion patterns that are produced by the diffuser. Experiments were performed with a model serpentine diffuser on the Annular Cascade …

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Best Practices Using Building Information Modeling In Commercial Construction, Simon Beveridge Dec 2012

Best Practices Using Building Information Modeling In Commercial Construction, Simon Beveridge

Theses and Dissertations

There has been an increase in adoption of building information modeling (BIM) by commercial contractors over the past few years but there is not a clear indication of current application or the frequency of each use. This research was undertaken to determine the frequency and best practices of using BIM in commercial construction. Leading commercial contracting firms were contacted and employees were selected to complete a telephone survey that was designed to determine how they are using BIM. It was found that BIM is being used with more frequency on projects, with plans to continue to implement it even further …

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Vibrotactile Feedback Generation Using Envelope Waveforms And Eccentric-Mass Motors, Michael G. Plooster Dec 2012

Vibrotactile Feedback Generation Using Envelope Waveforms And Eccentric-Mass Motors, Michael G. Plooster

Theses and Dissertations

The usefulness of vibrotactile feedback as a channel to communicate information has been widely recognized. However, most of the recent work on this subject uses actuators that are either too expensive or too large for many practical applications. This thesis explores the generation of vibrotacatile feedback patterns using a simple, inexpensive eccentric-mass motor that is constrained to use a constant voltage and a low on/off switching frequency. In particular, it explores the pulse timing method, which utilizes the slow transient response of the eccentric-mass motor to calculate pulse and rest times for an arbitrary envelope waveform shape. Several hardware tests …

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Internal Wave Generation Over Rough, Sloped Topography: An Experimental Study, Lauren Elizabeth Eberly Dec 2012

Internal Wave Generation Over Rough, Sloped Topography: An Experimental Study, Lauren Elizabeth Eberly

Theses and Dissertations

Internal waves exist everywhere in stratified fluids - fluids whose density changes with depth. The two largest bodies of stratified fluid are the atmosphere and ocean. Internal waves are generated from a variety of mechanisms. One common mechanism is wind forcing over repeated sinusoidal topography, like a series of hills. When modeling these waves, linear theory has been employed due to its ease and low computational cost. However, recent research has shown that non-linear effects, such as boundary layer separation, may have a dramatic impact on wave generation. This research has consisted of experimentation on sloped, sinusoidal hills. As of …

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Comparison Of 3-D Friction Stir Welding Viscoplastic Finite Element Model With Weld Data And Physically-Simulated Data, Maria Posada Dec 2012

Comparison Of 3-D Friction Stir Welding Viscoplastic Finite Element Model With Weld Data And Physically-Simulated Data, Maria Posada

Theses and Dissertations

Models (both physical and numerical) of the friction stir (FS) welding process are used to develop a greater understanding of the influence of independent process parameters on dependent process output variables, such as torque, power, specific weld energy, peak temperature, cooling rates and various metallurgical factors (e.g., grain size and precipitates). An understanding of how the independent process parameters influence output variables and ultimately their effect on resultant properties (e.g., strength, hardness, etc..) is desirable. Most models developed have been validated primarily for aluminum alloys with relatively small amounts of experimental data. Fewer models have been validated for steels or …

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Effective Collaboration Through Multi User Cax By Implementing New Methods Of Product Specification And Management, Vonn L. Holyoak Dec 2012

Effective Collaboration Through Multi User Cax By Implementing New Methods Of Product Specification And Management, Vonn L. Holyoak

Theses and Dissertations

This thesis presents a new design process in which design specifications and task distribution are determined from a parallel multi user prospective. Using this method, projects are more easily decomposed into tasks that can be performed concurrently, thus decreasing the design time. Also, a framework is provided to determine the correct distribution of available talent and stakeholders that can be utilized on a given project. The research suggests that by involving the necessary stakeholders in a multi user setting, changes can be made quickly and without additional approval wait time. By including individuals from the various areas of required talent, …

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An Optimization-Based Method Of Traversing Dynamic S-Pareto Frontiers, Patrick K. Lewis Nov 2012

An Optimization-Based Method Of Traversing Dynamic S-Pareto Frontiers, Patrick K. Lewis

Theses and Dissertations

The use of multiobjective optimization in identifying systems that account for changes in customer needs, operating environments, system design concepts, and analysis models over time is generally not explored. Providing solutions that anticipate, account for, and allow for these changes over time is a significant challenge to manufacturers and design engineers. Products that adapt to these changes through the addition and/or subtraction of modules can reduce production costs through product commonality, and cater to customization and adaptation. In terms of identifying sets of non-dominated designs, these changes result in the concept of dynamic Pareto frontiers, or dynamic s-Pareto frontiers …

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Measurement Of Thermal Diffusivities Using The Distributed Source, Finite Absorption Model, James B. Hall Nov 2012

Measurement Of Thermal Diffusivities Using The Distributed Source, Finite Absorption Model, James B. Hall

Theses and Dissertations

Thermal diffusivity in an important thermophysical property that quantifies the ratio of the rate at which heat is conducted through a material to the amount of energy stored in a material. The pulsed laser diffusion (PLD) method is a widely used technique for measuring thermal diffusivities of materials. This technique is based on the fact that the diffusivity of a sample may be inferred from measurement of the time-dependent temperature profile at a point on the surface of a sample that has been exposed to a pulse of radiant energy from a laser or flash lamp. An accepted standard approach …

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