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Articles 2521 - 2550 of 6329

Full-Text Articles in Engineering

Simulation And Optimization Of An In-Plane Thermal Conductivity Measurement Structure For Silicon Nanostructures, Y. Zeng, Amy Marconnet Oct 2015

Simulation And Optimization Of An In-Plane Thermal Conductivity Measurement Structure For Silicon Nanostructures, Y. Zeng, Amy Marconnet

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

Silicon-on-insulator based measurement structures have recently been developed to measure the thermal conductivity of nanostructured materials. For example, suspended steady-state measurement structures are often used for measuring the in-plane thermal conductivity of thin silicon films as the heat transfer is confined to the lateral direction. However, few researchers have focused on optimizing the important structural and measurement parameters, such as geometry and applied heater power levels, to ensure accurate measurements. In this article, numerical simulations are first compared with existing experimental data for suspended steady-state joule heating measurement structures with a large suspended region (~10 mm2). Then, a …


Design Of A Guarded Hot Plate For Measuring Thin Specimens Of Polymer And Composite Materials, Clark Stacey, M. J. Parfitt, A. J. Simpkin, J. Wu Oct 2015

Design Of A Guarded Hot Plate For Measuring Thin Specimens Of Polymer And Composite Materials, Clark Stacey, M. J. Parfitt, A. J. Simpkin, J. Wu

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

The National Physical Laboratory (NPL) has developed a new design of guarded hot plate apparatus specifically for absolute measurements on thin specimens of medium thermal conductivity materials, such as the polymer composites that are becoming more widely used in aerospace and other advanced manufacturing sectors. Although NPL has an existing measurement facility based on a commercially manufactured apparatus conforming to ASTM E1530, this current facility is not based on an absolute measurement technique and is not able to provide the low measurement uncertainty or flexibility that is increasingly being demanded by industrial users of this NPL service.

The target specification …


International Comparison Of Guarded Hot Plate Facilities At Low Temperature On Mineral Wool Insulation Material, Alain Koenen, Clark Stacey, Erik Rasmussen, Roland Schreiner, Grażyna Swołek Oct 2015

International Comparison Of Guarded Hot Plate Facilities At Low Temperature On Mineral Wool Insulation Material, Alain Koenen, Clark Stacey, Erik Rasmussen, Roland Schreiner, Grażyna Swołek

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

In 2000, the Institute for Reference Materials and Measurements (IRMM) proposed the creation of a new European certified reference material for the thermal conductivity measurements IRMM-440. A specific production batch of high density (64–78 kg/m3) resin-bonded glass fiber boards was manufactured and characterized by a group of six leading European laboratories with long-standing expertise in thermal conductivity measurements, including four national measurements institutes. The IRMM-440 has since been used as the European certified reference material for thermal conductivity measurements on thermal insulation covering temperatures between –10°C and 50°C, and most frequently to calibrate Heat Flow Meter apparatus making …


A New Facility For The Experimental Investigation On Nano Heat Transfer Between Gas Molecules And Ceramic Surfaces, D. Bayer, U. Gross, K. Raed Oct 2015

A New Facility For The Experimental Investigation On Nano Heat Transfer Between Gas Molecules And Ceramic Surfaces, D. Bayer, U. Gross, K. Raed

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

Since the last decade, the interest has risen in nanoscaled technological products, which have advantages through their size effect. The size effect also plays a significant role in the area of micro- and nanoscale heat transfers. Many applications were developed using this effect, such as nanostructured porous media, e.g. Aerogels or ceramics. This experimental work is focused on the determination of thermal accommodation coefficients (TAC) on ceramic surfaces considering several influencing factors. TAC is influenced by temperature, kind of gas, kind of wall material, roughness, and contamination with adsorbed gas layers. To determine TAC, a parallel plate apparatus is used, …


Heat Transfer Mechanisms In Porous Materials And Contemporary Problems In Thermophysical Properties Investigations: Analyses And Solutions, E. Litovsky, V. Issoupov, J. Kleiman Oct 2015

Heat Transfer Mechanisms In Porous Materials And Contemporary Problems In Thermophysical Properties Investigations: Analyses And Solutions, E. Litovsky, V. Issoupov, J. Kleiman

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

This article is an overview of the topical problems in the investigation of thermophysical properties and the development of a database for porous materials. Determination of both apparent/measured and true thermophysical properties is discussed taking into account combined heat and mass transfer, latent heat effects during chemical and physical transformations, as well as structural changes. The approaches to the solution of these problems are demonstrated for a number of different classes of materials:

  1. Industrial refractories, ceramics, highly porous insulation;
  2. Moist materials and materials undergoing phase, chemical and structural transformations;
  3. Materials semitransparent for heat radiation.

The approaches being used in the …


On The Development Of The Hot Strip, Hot Disc, And Pulse Hot Strip Methods For Measuring Thermal Transport Properties, Silas E. Gustafsson Oct 2015

On The Development Of The Hot Strip, Hot Disc, And Pulse Hot Strip Methods For Measuring Thermal Transport Properties, Silas E. Gustafsson

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

This review is focused on the development of experimental methods for measuring thermal transport properties. Special emphasis is given to plane probes, which are used both as heat sources and as temperature recording devices. With such probes it is under certain conditions possible to determine both the thermal conductivity and the thermal diffusivity from a single transient recording. The conditions which must be fulfilled in an experiment are introduced by the use of the concept of a thermal probing depth, and from which the time window of observations can be defined. The ultimate goal of the dual determination of the …


Designing A Mechanically Robust Thermoelectric Module For High Temperature Application, Amirkoushyar Ziabari, Kazuaki Yazawa, Ali Shakouri Oct 2015

Designing A Mechanically Robust Thermoelectric Module For High Temperature Application, Amirkoushyar Ziabari, Kazuaki Yazawa, Ali Shakouri

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

We report a numerical study on the impacts of variations in the geometry, boundary conditions, and the coefficient of thermal expansion of the materials on the maximum shearing stress in thermoelectric power generator module (TEM) for high temperature applications. The maximum shearing stress in the TEM is evaluated for different designs focusing on their dependency on the fill factor. Although predictions by the previously developed analytical modeling are in partial agreement with numerical results, simplifying assumptions for the analytical model can limit the range of validity. Our numerical analysis shows that reduction of the fill factor alone under all the …


Simulation And Analysis Of An Integrated Device To Simultaneously Characterize Thermal And Thermoelectric Properties, Collier Miers, Amy Marconnet Oct 2015

Simulation And Analysis Of An Integrated Device To Simultaneously Characterize Thermal And Thermoelectric Properties, Collier Miers, Amy Marconnet

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

For many applications, multiple material properties impact device performance and characterization of multiple properties using a single sample is desirable. In this article, the authors focus on thermoelectric materials characterization, which requires the thermal conductivity, electrical conductivity, and Seebeck coefficient to be quantified. Specifically, the authors present a design analysis using numerical COMSOL simulations of the 3w technique to optimize a measurement structure for thermoelectric films while also including the capability for electrical measurements to be performed on the same sample without detachment or repositioning. Thermal optimization of the structure is achieved through investigation of temperature spatial uniformity, the …


Role Of Thermal Conductivity For Thermoelectrics With Finite Contacts, Yee Rui Koh, Kazuaki Yazawa, Ali Shakouri Oct 2015

Role Of Thermal Conductivity For Thermoelectrics With Finite Contacts, Yee Rui Koh, Kazuaki Yazawa, Ali Shakouri

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

The role of thermal conductivity in the performance of thermoelectric (TE) devices as compared to other material properties such as Seebeck coefficient and the electrical conductivity will be discussed. A TE energy conversion system that includes thermal contacts for the hot side and the cold side with finite heat transfer performances is considered. Some of the trends in electronics cooling applications have been described. In this article, the effect of material properties as a function of energy current flow direction will be focused.

TEs have an advantage as solid-state heat energy conversion devices especially for applications with spatial constraints. A …


Comparative Testing Of Thermal Conductivity For Thermal Insulation Products: The European Keymark Experience For More Than 50 Equipment At 25 Test Institutes, Erik Rasmussen, Clark Stacey, Alain Koenen, Eva-Lotta W. Kurkinen Oct 2015

Comparative Testing Of Thermal Conductivity For Thermal Insulation Products: The European Keymark Experience For More Than 50 Equipment At 25 Test Institutes, Erik Rasmussen, Clark Stacey, Alain Koenen, Eva-Lotta W. Kurkinen

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

This article describes comparative testing of thermal conductivity on a range of thermal insulation products used in the construction of buildings. This testing was arranged by the CEN Keymark scheme for voluntary certification of insulation within Europe, and measurements have been performed using over 50 instruments in more than 25 registered laboratories.

The uniformity of the material and a unique thermal conductivity value for each set of test specimens that were used in the comparison have been established according to the Keymark scheme rules, which were developed by experts from the most respected European laboratories. These experts include most of …


Determination Of The Thermal Resistance Of Pipe Insulation Material From Thermal Conductivity Of Flat Insulation Products, Alain Koenen, Damien M. Marquis Oct 2015

Determination Of The Thermal Resistance Of Pipe Insulation Material From Thermal Conductivity Of Flat Insulation Products, Alain Koenen, Damien M. Marquis

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

New European product standards now include a mandatory requirement for manufacturers to declare the temperature-dependent thermal conductivity for each insulation used in building equipments and industrial installations. For pipe insulation systems, the measurement is usually performed by a standard pipe test method, in which the value on a large temperature range is integrated to reduce temperature range and improve temperature measurement control. The alternative proposed in this article consists in determining the thermal conductivity of a pipe insulation system from the results measured on a flat slab specimen. The protocol used in this study consists in collecting the thermal conductivity …


Flexible Buffer Materials To Reduce Contact Resistance In Thermal Insulation Measurements, R. E. Clarke, G. Rosengarten, B. Shabani Oct 2015

Flexible Buffer Materials To Reduce Contact Resistance In Thermal Insulation Measurements, R. E. Clarke, G. Rosengarten, B. Shabani

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

Thermal insulation test methods approach their lower limits as thermal resistance falls below 0.1 m2⋅K/W. This is the minimum value specified in ASTM C 518 (ASTM International, 2010b) while ASTM C 177 (ASTM International, 2010a) proposes about 0.06 m2⋅K/W. Nevertheless these are the test methods, along with their ISO equivalents, required by Australasian building codes and directed at many products and materials with thermal resistance on the low side of 0.1 m2⋅K/W. Alternatives, such as ASTM E 1530 (ASTM International, 2011), cover much lower resistances but require carefully prepared small specimens and very-high contact …


Bilateral National Metrology Institute Comparison Of Guarded-Hot-Plate Apparatus, Alain Koenen, Robert R. Zarr, William F. Guthrie Oct 2015

Bilateral National Metrology Institute Comparison Of Guarded-Hot-Plate Apparatus, Alain Koenen, Robert R. Zarr, William F. Guthrie

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

Two national metrology institutes have conducted an international interlaboratory comparison on thermal conductivity for two thermal insulation reference materials. The Laboratoire national de métrologie et d’essais (LNE), France, and the National Institute of Standards and Technology (NIST), United States, present measurements obtained by the guarded-hot-plate method. The study involved two materials: expanded polystyrene board (EPS) and fibrous glass board (FGB). The EPS was provided by the LNE and is issued as a transfer specimen; the FGB provided by NIST was issued as Standard Reference Material (SRM) 1450c. For each reference material, the study was based on four independent measurements at …


Plenary Talks, General Sessions, And Session Chairs, Timothy S. Fisher, Amy Marconnet Oct 2015

Plenary Talks, General Sessions, And Session Chairs, Timothy S. Fisher, Amy Marconnet

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

No abstract provided.


In Memoriam, Timothy S. Fisher, Amy Marconnet Oct 2015

In Memoriam, Timothy S. Fisher, Amy Marconnet

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

No abstract provided.


Foreword, Timothy S. Fisher, Amy Marconnet Oct 2015

Foreword, Timothy S. Fisher, Amy Marconnet

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

No abstract provided.


Table Of Contents, Timothy S. Fisher, Amy Marconnet Oct 2015

Table Of Contents, Timothy S. Fisher, Amy Marconnet

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

No abstract provided.


Microstructure And Thermal Conductivity Modeling Of Granular Nanoplatelet Assemblies, Ishan Srivastava, Timothy S. Fisher Oct 2015

Microstructure And Thermal Conductivity Modeling Of Granular Nanoplatelet Assemblies, Ishan Srivastava, Timothy S. Fisher

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

Consolidation and sintering of bismuth telluride nanoplatelets is a cost-effective method of manufacturing high thermoelectric figure-of-merit materials. A structural optimization method is employed here to study the effects of columnar structures formed by nanoplatelet composites on thermal transport. The initially sparse and random distribution of nanoplatelets is compacted into a jammed state under an external hydrostatic stress, thereby simulating the compaction of nanopowders in experiments. The jammed morphology exhibits randomly oriented stacks of nanoplatelets and a discontinuous distribution of the pore phase within the microstructure. Grain and pore morphologies are statistically quantified using computational geometry techniques. High aspect ratio nanoplatelets …


Metal Hydride Component Design (Mhy-Code) Tool For The Selection Of Hydrides In Thermal Systems, Essene L. Waters, Timothée L. Pourpoint, Tyler G. Voskuilen Oct 2015

Metal Hydride Component Design (Mhy-Code) Tool For The Selection Of Hydrides In Thermal Systems, Essene L. Waters, Timothée L. Pourpoint, Tyler G. Voskuilen

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

A system has been developed to enable the targeted down-selection of an extensive database of metal hydrides to identify the most promising materials for use in thermal systems. The materials’ database contains over 300 metal hydrides with various physical and thermodynamic properties included for each material. Submodels for equilibrium pressure, thermophysical data, and default properties are used to predict the behavior of each material within the given system. The application used at this time is a stationary combined heat and power system containing a hightemperature proton exchange membrane (PEM) fuel cell, a hot water tank, and two metal hydride beds …


Characterization Work And Comparative Testing Of Expanded Glass Granulate As A Round Robin Material For Thermal Conductivity At Higher Temperatures, Roland Schreiner, Ernst-G. Hencke Oct 2015

Characterization Work And Comparative Testing Of Expanded Glass Granulate As A Round Robin Material For Thermal Conductivity At Higher Temperatures, Roland Schreiner, Ernst-G. Hencke

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

For laboratories within the scheme of the voluntary surveillance system for technical insulation materials in Europe (VDI/Keymark), a proficiency test is the basis for obtaining a “registered laboratory.” The VDI/Keymark is a cooperation between the VDI, The Association of German Engineers, and the Keymark Group dealing with European voluntary product certification systems, within the scope of thermal insulation materials. Registered laboratories are allowed to conduct measurements to verify the declared thermal conductivity curve of technical insulation materials under the umbrella of the quality mark “VDI/Keymark”. The initial characterization work on a round robin material for the determination of thermal conductivity …


Thermal Conductivity Of Simulated Soils By The Needle Probe Method For Energy Foundation Applications, J. E. Low, F. A. Loveridge, W. Powrie Oct 2015

Thermal Conductivity Of Simulated Soils By The Needle Probe Method For Energy Foundation Applications, J. E. Low, F. A. Loveridge, W. Powrie

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

Soil thermal conductivity is an important parameter in the design of ground source heat pump and energy foundation systems. A laboratory method for measuring the soil thermal conductivity is the needle probe method. Earlier, analysis of the needle probe test data has been simplistic, relying heavily on human judgment and rules of thumb. This article presents an alternative method of analyzing the needle probe data with the aid of MATLAB, which is a technical programming language and computing environment. Four agar–kaolin specimens of varying densities were prepared to resemble simple soils. These were tested using the needle probe for a …


Dynamic Triaxial Compression Experiments On Borosilicate And Soda-Lime Glass, John T. Chojnacki Oct 2015

Dynamic Triaxial Compression Experiments On Borosilicate And Soda-Lime Glass, John T. Chojnacki

Open Access Theses

A series of compression experiments were performed on borosilicate and soda-lime glass using a triaxial compression Kolsky bar. The triaxial compression Kolsky bar differs from a traditional Kolsky bar by having two pressure chambers, one enclosing the specimen and the other enclosing the end of the transmission bar, so that a specimen may be pre-stressed axially and radially before a dynamic axial load is applied. The result is a modified Kolsky bar capable of measuring axial deformation and axial stresses of a specimen at various strain rates under a range of confinement pressures. Borosilicate glass was subjected to triaxial confinement …


2015 Statewide Bridge Sufficiency Rating Report - Condensed, Indiana Ltap, Indiana Department Of Transportation, Indiana Department Of Local Government Finance Oct 2015

2015 Statewide Bridge Sufficiency Rating Report - Condensed, Indiana Ltap, Indiana Department Of Transportation, Indiana Department Of Local Government Finance

Indiana Local Technical Assistance Program (LTAP) Publications

The main purpose of this report is to provide bridge sufficiency rating information for the bridges in each county to county officials as a convenient starting point for formulating a long-range plan to cope with their county bridge deficiencies. This information results from the data generated by the national Bridge Inspection Standards (NBIS) program authorized by the 1968 Federal-Aid Highway Act.


2015 Statewide Bridge Sufficiency Rating Report - Full, Indiana Ltap, Indiana Department Of Transportation, Indiana Department Of Local Government Finance Oct 2015

2015 Statewide Bridge Sufficiency Rating Report - Full, Indiana Ltap, Indiana Department Of Transportation, Indiana Department Of Local Government Finance

Indiana Local Technical Assistance Program (LTAP) Publications

The main purpose of this report is to provide bridge sufficiency rating information for the bridges in each county to county officials as a convenient starting point for formulating a long-range plan to cope with their county bridge deficiencies. This information results from the data generated by the national Bridge Inspection Standards (NBIS) program authorized by the 1968 Federal-Aid Highway Act.


Causes And Trends In Maintenance-Related Accidents In Faa-Certified Single Engine Piston Aircraft, Douglas Boyd, Alan Stolzer Sep 2015

Causes And Trends In Maintenance-Related Accidents In Faa-Certified Single Engine Piston Aircraft, Douglas Boyd, Alan Stolzer

Journal of Aviation Technology and Engineering

The accident rate for general aviation remains high. While most general aviation accident studies have been pilot-focused, there is little research on the involvement of aircraft maintenance errors. We undertook a study to answer this question.

The Microsoft Access database was queried for accidents occurring between 1989 and 2013 involving single engine piston airplanes operating under 14CFR Part 91. Pearson Chi-Square, Fisher’s Exact Test, and Poisson probability were used in statistical analyses.

The rate of maintenance-related general aviation accidents was 4.3 per million flight hours for the 1989–1993 period and remained unchanged for the most recent period (2009–2013). Maintenance errors …


Molexpl: A Tool For Ab Initio Data Exploration And Visualization, Xueying Wang, Nicolas Onofrio, Alejandro Strachan Sep 2015

Molexpl: A Tool For Ab Initio Data Exploration And Visualization, Xueying Wang, Nicolas Onofrio, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Density functional theory (DFT) based on ab initio theory, is a powerful method to resolve the electronic structure of atoms, molecules and solids. However, in practical, DFT is limited to few hundreds of atoms. To overcome this limitation, researchers have developed empirical interatomic potentials implemented in molecular dynamics (MD) simulations. MD ignores the movements of electrons and describes bonding and non-bonding interaction as a function of the distance between atoms called force fields (FF) or interatomic potentials. These empirical potentials are optimized against large datasets of DFT calculations relevant to describe the interactions between the atoms included in the training …


Synthesis Of Unmanned Aircraft Systems Safety Reports, Robert Joslin Aug 2015

Synthesis Of Unmanned Aircraft Systems Safety Reports, Robert Joslin

Journal of Aviation Technology and Engineering

The proliferation and extension of unmanned aircraft systems from military to civil and public use applications has rapidly outpaced the safety analysis that is normally associated with the introduction of a new and novel aircraft. Insights into the types of anomalous events associated with accidents and incidents involving civil and public use unmanned aircraft systems operating in the National Airspace System were derived from an information synthesis of archival, publically available reports from the Aviation Safety Information and Analysis Sharing system. The vast majority of anomalous events were related to equipment failures, primarily lost link, distantly followed by a variety …


Vertical Icf Wall System, Purdue Ect Team Aug 2015

Vertical Icf Wall System, Purdue Ect Team

ECT Fact Sheets Archive

Traditional ICF systems’ installation is tedious and labor intensive resulting in out of level, bowing, and snaking walls with a significant amount of bracing adding to the cost. ICF (Insulated Concrete Form) walls are a form of structural walls used for construction. Hobbs Vertical ICF system uses less concrete, more recycled material and requires less labor for construction. The furring assemblies and retainer clips of the Hobbs VICF system are made from 100% recycled post-industrial waste.


Prefabricated Building, Purdue Ect Team Aug 2015

Prefabricated Building, Purdue Ect Team

ECT Fact Sheets Archive

With the continuous demand for construction of new buildings, an easier, more sustainable, energy-efficient and environmentally friendly building method is necessary to save time, energy and cost. Hence, there has been an increasing need for a system such as BROAD sustainable building (BSB). A form of prefabricated building by BROAD Sustainable Building Co., LTD (BSB). It consists of flooring and ceiling, embedded shafts of ventilation, water supply & drainage, electricity and lighting. Other items include pillars, diagonal bracings, doors, windows, walls and sanitary wares, air conditioning, air quality products, lifts, building thermal insulations.


Post-Tensioned Concrete Shear Wall, Purdue Ect Team Aug 2015

Post-Tensioned Concrete Shear Wall, Purdue Ect Team

ECT Fact Sheets Archive

The post-tension concrete shear wall by Tipping Mar will replace the conventional concrete shear wall in earthquake prone areas in many instances, depending on the height and scale of the building.