scholarly journals Review on hardfacing as method of improving the service life of critical components subjected to wear in service

2018 ◽  
Vol 36 (4) ◽  
pp. 1095 ◽  
Author(s):  
C Okechukwu ◽  
O.A. Dahunsi ◽  
P.K. Oke ◽  
I.O. Oladele ◽  
M Dauda
Keyword(s):  
Service Life ◽  
Critical Components

ULTRA 76 TANTALUM

Alloy Digest ◽  
2010 ◽  
Vol 59 (5) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Service Life ◽  
Physical Properties ◽  
Tensile Properties ◽  
Cost Effective ◽  
Heat Treating ◽  
Process Industry ◽  
Industry Applications ◽  
Critical Components ◽  
Corrosive Environments

Abstract ULTRA 76 TANTALUM alloys have been used in various process industry applications requiring resistance to aggressive, hazardous chemicals. These tantalum alloys provide cost-effective, long service-life for critical components in severe (corrosive) environments. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as heat treating. Filing Code: TA-13. Producer or source: H.C. Starck Inc.

On the search for optimal damage precursors

2014 ◽  
Vol 13 (6) ◽  
pp. 601-608 ◽  
Author(s):  
Volker Weiss ◽  
Anindya Ghoshal
Keyword(s):  
Service Life ◽  
Crack Length ◽  
Microstructural Characterization ◽  
Phase Changes ◽  
Material Loss ◽  
Damage Indicator ◽  
Damage Indicators ◽  
Critical Components ◽  
Life Predictions ◽  
Indicator Ratio

A new approach to predict the service life of critical components via study of damage precursors is emerging and is the topic of this article. To date, most service life predictions are based on measurements of damage indicators and their growth toward criticality or failure, for example, fatigue crack length and material loss due to corrosion or wear. This makes lifetime estimates based on measurements of damage, for example, around half-life, or even at 80% life, difficult and inaccurate. To improve the accuracy and reliability of lifetime prediction, efforts are now underway to determine the state awareness of a critical component during service, based on property characterizations, in addition to the measurements of the direct damage indicators, such as crack length, acoustic emission, ultrasound signals, and eddy current measurements. These characterizations will include indirect damage indicators, that is, precursors and allied or affiliated damage indicators. For affiliated damage indicators, residual stress relaxation or development, phase changes, electrical property (resistivity, dielectric constant, permeability), and microstructural characterization must be considered. The selection of the optimal combination of direct and indirect damage indicators will be application specific. It is proposed to assess the efficacy of damage indicators on the basis of their Di/Df versus Ni/Nf, that is, damage ratio versus life fraction curves (referred to as damage indicator ratio curves), searching for indicators with damage indicator ratio curves that best meet the needs of the application.

scholarly journals Determining the Aging Performance of Vacuum Insulation Panels: Development of a Prediction Model

2021 ◽  
Author(s):  
Melissa Morlidge
Keyword(s):  
Service Life ◽  
Thermal Resistance ◽  
Accelerated Aging ◽  
Extended Period ◽  
Building Envelope ◽  
Core Material ◽  
Vacuum Insulation ◽  
Critical Components ◽  
Quality Material ◽  
Metallic Foils

Vacuum insulation panels (VIPs) are increasingly being explored in building applications. Typically used in industrial processes such as aerospace engineering, cryogenics and refrigerator manufacturing, VIPs have been proven to provide a higher thermal resistance per inch than typical building insulation materials. However, there is speculation on the performance of these panels over an extended period of time due to various factors which gradually cause a reduction in thermal resistance. The purpose of this research project is to identify these variables and how they alter VIP performance over the product’s service life. Based on a thorough literature review, the critical components were interpreted to develop a numerical model which can predict the future performance of VIPs as they age, based on initial material properties. This model is intended to benefit designers and researchers in the construction industry; in understanding the potential for vacuum insulation to contribute to building envelope design. The results of calculation proved to be complementary to experimental results provided by the NRC, (initial calculated conductivities ranged from 4.17x10 The highest calculated conductivity was attributed to the low quality metalized (MF) VIP with a final conductivity after accelerated aging of 5.29 x 10 Some observations included that there is little difference between aluminum and metallic foils in their initial conductivity; however the aluminum foils represented in this report outperformed the chosen metallic foils over time, as they provided smaller gas and water vapour transmission rates. The core material variables with the greatest impact on performance were density and porosity. Some of the simulated panels exceeded the conductivity limit before the end of their service life, while others did not. Therefore the conclusion for VIP performance overall cannot be confirmed, although the development of standards within the industry would ensure high quality material integration within building systems.

scholarly journals Significance of Fatigue Damage from Overload Trucks on Bridge Load Rating

2018 ◽  
Vol 165 ◽  
pp. 10005 ◽  
Author(s):  
Bora Jang ◽  
Jamshid Mohammadi
Keyword(s):  
Service Life ◽  
Fatigue Damage ◽  
The United States ◽  
Load Rating ◽  
Steel Girder ◽  
Girder Bridges ◽  
Steel Girder Bridges ◽  
Critical Components ◽  
Truck Load ◽  
The Impact

Overload trucks constitute a major portion of truck load populations on highways. Specific to bridges, the increase in the frequency of overloads may trigger shortening of service life of critical components because of fatigue damage, considering the fact that fatigue damage accelerates at higher loads. This is especially important to older bridges that have been designed for loads lower than the standard for current highway bridge design in the United States. As the number of requests for special permits to use bridges by overload trucks increases, the accumulated damage may substantially reduce the service life of bridges resulting in costly repair and replacements. In this paper, the significance of overloads in causing fatigue damage to bridges is discussed. Samples of truck load data have been compiled and used to determine the contribution of overloads to fatigue damage for steel girder bridges made up of welded cover plates. The paper discusses using the expected fatigue life expended (FLE) as an index to determine the impact of overloads on bridge fatigue damage. The FLE is then determined to be an important factor that can be used to modify bridge rating equations as a way of controlling the number of overload permits for a given bridge.

scholarly journals Determining the Aging Performance of Vacuum Insulation Panels: Development of a Prediction Model

2021 ◽  
Author(s):  
Melissa Morlidge
Keyword(s):  
Service Life ◽  
Thermal Resistance ◽  
Accelerated Aging ◽  
Extended Period ◽  
Building Envelope ◽  
Core Material ◽  
Vacuum Insulation ◽  
Critical Components ◽  
Quality Material ◽  
Metallic Foils

Vacuum insulation panels (VIPs) are increasingly being explored in building applications. Typically used in industrial processes such as aerospace engineering, cryogenics and refrigerator manufacturing, VIPs have been proven to provide a higher thermal resistance per inch than typical building insulation materials. However, there is speculation on the performance of these panels over an extended period of time due to various factors which gradually cause a reduction in thermal resistance. The purpose of this research project is to identify these variables and how they alter VIP performance over the product’s service life. Based on a thorough literature review, the critical components were interpreted to develop a numerical model which can predict the future performance of VIPs as they age, based on initial material properties. This model is intended to benefit designers and researchers in the construction industry; in understanding the potential for vacuum insulation to contribute to building envelope design. The results of calculation proved to be complementary to experimental results provided by the NRC, (initial calculated conductivities ranged from 4.17x10 The highest calculated conductivity was attributed to the low quality metalized (MF) VIP with a final conductivity after accelerated aging of 5.29 x 10 Some observations included that there is little difference between aluminum and metallic foils in their initial conductivity; however the aluminum foils represented in this report outperformed the chosen metallic foils over time, as they provided smaller gas and water vapour transmission rates. The core material variables with the greatest impact on performance were density and porosity. Some of the simulated panels exceeded the conductivity limit before the end of their service life, while others did not. Therefore the conclusion for VIP performance overall cannot be confirmed, although the development of standards within the industry would ensure high quality material integration within building systems.

Experience with the Introduction of SAFT Testing in Volume Production of Large Forged Parts

NDT World ◽  
2021 ◽  
pp. 18-24
Author(s):  
Johannes Vrana ◽  
Alexander Zimmer ◽  
Karsten Schörner ◽  
Hubert Mooshofer ◽  
Karsten Kolk
Keyword(s):  
Power Generation ◽  
Detection Limit ◽  
Service Life ◽  
Synthetic Aperture ◽  
Forged Parts ◽  
Volume Production ◽  
Critical Components ◽  
Level 2 ◽  
Sensitive Testing ◽  
Large Rotor

Large rotor forged parts, which are usually one of the most critical components in land-based turbines and generators for power generation, require a complex volumetric test for a sufficient service life. This is usually performed manually or automatically with ultrasound. New requirements, designs and materials require more sensitive testing. This can be achieved by SAFT, also called ultrasound computer tomography. SAFT is based on the Synthetic Aperture Radar (SAR) and has been further developed by several universities. The introduction of SAFT in the volume production of large forged parts was achieved by the introduction of the quantitative SAFT developed by Siemens, also called AVG or DGS-SAFT, which allows an evaluation of each voxel in units of a replacement reflector, and by an acceleration that allows the reconstruction of the complete volume of a large forged component, which could be obtained when the SAFT test was introduced into volume production. The challenges for level 2/3 reviewers are discussed, such as volume-corrected display of results, handling of large amounts of data, focusing of displays, amplitude representation in units of a replacement reflector and handling of the software. Furthermore, it is shown how displays are represented by SAFT, how the detection limit can be determined in the case of quantitative SAFT, and which artifacts can occur during series testing with SAFT.

The Role of the SLP in Autism Spectrum Disorder Screening and Assessment

2008 ◽  
Vol 15 (2) ◽  
pp. 50-59 ◽  
Author(s):  
Amy Philofsky
Keyword(s):  
Language Development ◽  
Critical Role ◽  
Children With Autism ◽  
Autism Spectrum ◽  
Children With Asd ◽  
Prevalence Estimates ◽  
Notable Increase ◽  
Screening Assessment ◽  
Critical Components

AbstractRecent prevalence estimates for autism have been alarming as a function of the notable increase. Speech-language pathologists play a critical role in screening, assessment and intervention for children with autism. This article reviews signs that may be indicative of autism at different stages of language development, and discusses the importance of several psychometric properties—sensitivity and specificity—in utilizing screening measures for children with autism. Critical components of assessment for children with autism are reviewed. This article concludes with examples of intervention targets for children with ASD at various levels of language development.

Faith-Based Health Education Project

2003 ◽  
Vol 1 (2) ◽  
pp. 208-222 ◽  
Author(s):  
Georgia N. L. Johnston
Keyword(s):  
Faith Communities ◽  
Face To Face ◽  
Staff Members ◽  
Community Ownership ◽  
Faith Based ◽  
Program Success ◽  
Project Sustainability ◽  
Critical Components ◽  
Pastoral Support ◽  
Volunteer Commitment

Working with faith communities in health promotion is widely acclaimed and yet not readily practiced. This article describes a study conducted among four faith communities to determine the process required for sustainable faith-based programs. Face-to-face interviews were conducted among 12 community volunteers who participated to identify their perceptions of the project. Two staff members were also interviewed to identify the process from their perspectives. Project-related documents were also analyzed to provide details and triangulate the data from the interviews. The study followed the project for 2 ½ years. Several factors were identified as significant influences on participation and project sustainability. These included value, active pastoral support, program success, and volunteer commitment. The results of this study indicate that pastoral support and faith community ownership are critical components that should be included in faith-based community building efforts.

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