25 results match your criteria in-service durability

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Effect of Wave Process of Plastic Deformation at Forging on the Fatigue Fracture Mechanism of Titanium Compressor Disks of Gas Turbine Engine.

Materials (Basel) 2021 Apr 8;14(8). Epub 2021 Apr 8.

Institute of Computer Aided Design, 2nd Brestskaya street 19/18, 123056 Moscow, Russia.

The low-cycle fatigue behavior of the VT3-1 titanium alloy (Ti-6Al-3Mo-2Cr alloy) under loading with a triangular and trapezoidal shape of cycle waveform was studied on round specimens prepared from forged compressor disks of a gas turbine engine. The filament type structure after forging has alternating filaments with the ductile and quasi-brittle state of the metal as a result of the wave process of plastic deformation during the metal forging process. The crack propagation, regardless of the cyclic waveform shape, occurs by the crack meso-tunneling mechanism: initially, the cracks propagate along the filaments by a quasi-brittle mechanism with the formation of a facetted pattern relief on the fracture surface reflecting the two-phase structure of the titanium alloy, and then, the bridge between the meso-tunnels is fractured with the formation of fatigue striations. Read More

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Reliability Prediction of Acrylonitrile O-Ring for Nuclear Power Applications Based on Shore Hardness Measurements.

Polymers (Basel) 2021 Mar 19;13(6). Epub 2021 Mar 19.

Department of Manufacturing Engineering, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain.

The degradation of polymeric components is of considerable interest to the nuclear industry and its regulatory bodies. The objective of this work was the development of a methodology to determine the useful life-based on the storage temperature-of acrylonitrile O-rings used as mechanical sealing elements to prevent leakages in nuclear equipment. To this aim, a reliability-based approach that allows prediction of the use-suitability of different storage scenarios (that involve different storage times and temperatures) considering the further required in-service performance, is presented. Read More

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Environmental Impacts of Glass- and Carbon-Fiber-Reinforced Polymer Bar-Reinforced Seawater and Sea Sand Concrete Beams Used in Marine Environments: An LCA Case Study.

Polymers (Basel) 2021 Jan 2;13(1). Epub 2021 Jan 2.

Key Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology), Ministry of Education, Harbin 150090, China.

Application of glass- or carbon-fiber-reinforced polymer (GFRP/CFRP) bars makes the direct use of seawater and sea sand concrete (SWSSC) in construction feasible, which is of high interest in order to conserve the limited resources of fresh water and river sand. The present paper performed the life cycle assessment (LCA) of constructing three kinds of beams (GFRP/CFRP bar-reinforced SWSSC beams, and steel bar-reinforced common concrete (SRC) beam) in marine environments to show the environmental benefits of using FRP bar-reinforced SWSSC beams in marine environments. According to ISO 14040 and ISO 14044, stages including production, transportation, construction, use and end-of-life are within the LCA's boundary. Read More

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January 2021

Composite Behavior of RC-HPFRC Tension Members under Service Loads.

Materials (Basel) 2020 Dec 24;14(1). Epub 2020 Dec 24.

Department Continuum Mechanics and Structures, Universidad Politécnica de Madrid, ETS Ingenieros de Caminos, 28040 Madrid, Spain.

A significant increase of the use of high-performance fiber-reinforced concrete (HPFRC) to strengthen reinforced concrete structures (RC) has been noted for the past few years, thereby achieving composite RC-HPFRC elements. Such a technique tries to take advantage of the superior material properties of HPFRC in the ultimate and service load regimes. Many of the existing works on RC-HPFRC elements have focused on the strength increase at the ultimate load state and much less effort has been devoted to the serviceability response. Read More

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December 2020

Advances in the Deformation and Failure of Concrete Pavement under Coupling Action of Moisture, Temperature, and Wheel Load.

Materials (Basel) 2020 Dec 4;13(23). Epub 2020 Dec 4.

School of Architectural and Civil Engineering, Anhui University of Technology, Ma'anshan 243032, China.

The deformation and cracking of concrete will lead to various deterioration processes, which will greatly reduce the durability and service life of the concrete pavement. The relating previous studies and analysis revealed that the coupling action of environmental temperature, moisture, and wheel load will cause cracking and seriously affect the normal service and durability of pavement concrete. This paper presents theoretical and numerical state-of-the-art information in the field of deformation and failure of pavement concrete under coupling action of moisture, temperature, and wheel load and draws some conclusions. Read More

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December 2020

Reliability-Based Evaluation of the Suitability of Polymers for Additive Manufacturing Intended for Extreme Operating Conditions.

Polymers (Basel) 2020 Oct 12;12(10). Epub 2020 Oct 12.

Department of Manufacturing Engineering, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain.

A reliability engineering program must be implemented from the conceptual phase of the physical asset to define the performance requirements of the components and equipment. Thus, in this work, the aim is to find the most optimal solution to manufacture polymer-based parts for the nuclear power industry using additive manufacturing routes. This case study application has been selected because polymers processed by additive manufacturing (AM) can be well suited for nuclear applications. Read More

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October 2020

Effects of External Environments on the Fixed Elongation and Tensile Properties of the VAE Emulsion-Cement Composite Joint Sealant.

Materials (Basel) 2020 Jul 21;13(14). Epub 2020 Jul 21.

Aeronautics Engineering College, Air Force Engineering University, Xi'an 710038, China.

Joint sealant is affected by various environmental factors in service, such as different temperatures, water soaking, ultraviolet and so on. In this paper, the VAE emulsion-cement compositejoint sealant was pretreated under multiple simulation environments. Thereafter, the degradation rules of fixed elongation and tensile properties of joint sealants at different mix proportions were systemically investigated under the action of external environments (temperature, water soaking and ultraviolet), and the influence mechanisms of diverse environmental factors were analyzed. Read More

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The effects on oxidative aging, physical and flow properties of Agbabu natural bitumen modified with silver nanoparticles.

Heliyon 2020 Jun 27;6(6):e04164. Epub 2020 Jun 27.

Department of Pure and Applied Chemistry, Ladoke Akintola Universityof Technology, Ogbomoso, P.M.B. 4000, Nigeria.

The quest for improvement in service life and performance of road pavement via reduction of oxidative aging failure of bitumen, led us to the investigation of novel application of Silver nanoparticles (AgNPs) as potential anti-oxidative material for Agbabu natural bitumen (ANB). The raw ANB was purified to form the base and the base modified in a stainless reactor using AgNPs via melt blend technique at temperature of 120 °C under stirring at 1200rpm. The proportions of AgNPs used for the modification were 1. Read More

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Recycling of a Concrete Pavement after over 80 Years in Service.

Materials (Basel) 2020 May 14;13(10). Epub 2020 May 14.

Department of Road and Bridge Engineering, West Pomeranian University of Technology in Szczecin, 50 Piastow St., 70-311 Szczecin, Poland.

This article presents the results of fatigue testing and assessment of the mechanical and physical properties of the concrete pavement of the A6 motorway, which was put in service in 1938. After 82 years of operation under heavy traffic loading conditions, the pavement was fully recycled by crushing of the existing concrete and reuse of the reclaimed material in the new courses of pavement placed as part of the motorway renewal project. The main objective of this research was to determine the properties of the tested concrete, including compressive strength, water absorption and freeze-thaw resistance after 150 cycles of alternate freezing and thawing. Read More

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Study on the Durability of the T-Beam Based on Chloride Ion Erosion.

Materials (Basel) 2020 Mar 25;13(7). Epub 2020 Mar 25.

School of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, China.

Based on analyzing the bearing capacity of existing T-beam bridges in service, the factors that affect the T-beams cracked by chloride ions mainly include the width and the depth of cracks. Combined with practical engineering examples, a single-piece T-beam model is established to explore the influence of factors such as crack width and crack depth on the T-beams affected by chloride ion erosion through numerical simulation in this paper. In addition, the attenuation models of bending capacity and shear capacity of the T-beam are obtained to analyze the possible failure modes of T-beams with cracks. Read More

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Requirements and Variability Affecting the Durability of Bonded Joints.

Materials (Basel) 2020 Mar 23;13(6). Epub 2020 Mar 23.

Department of Mechanical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, UK.

This paper firstly reveals that when assessing if a bonded joint meets the certification requirements inherent in MIL-STD-1530D and the US Joint Services Standard JSSG2006 it is necessary to ensure that: (a) There is no yielding at all in the adhesive layer at 115% of design limit load (DLL), and (b) that the joint must be able to withstand design ultimate load (DUL). Secondly, it is revealed that fatigue crack growth in both nano-reinforced epoxies, and structural adhesives can be captured using the Hartman-Schijve crack growth equation, and that the scatter in crack growth in adhesives can be modelled by allowing for variability in the fatigue threshold. Thirdly, a methodology was established for estimating a valid upper-bound curve, for cohesive failure in the adhesive, which encompasses all the experimental data and provides a conservative fatigue crack growth curve. Read More

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Wood-water relationships and their role for wood susceptibility to fungal decay.

Appl Microbiol Biotechnol 2020 May 6;104(9):3781-3795. Epub 2020 Mar 6.

Norwegian Institute of Bioeconomy Research (NIBIO), Division of Forest and Forest Resources, Wood Technology, Høgskoleveien 8, 1433, Ås, Norway.

Wood in service is sequestering carbon, but it is principally prone to deterioration where different fungi metabolize wood, and carbon dioxide is released back to the atmosphere. A key prerequisite for fungal degradation of wood is the presence of moisture. Conversely, keeping wood dry is the most effective way to protect wood from wood degradation and for long-term binding of carbon. Read More

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Prediction of RC Bridge Member Resistance Decreasing in Time under Various Conditions in Slovakia.

Materials (Basel) 2020 Mar 3;13(5). Epub 2020 Mar 3.

Department of Structures and Bridges, Faculty of Civil Engineering, University of Žilina, 010 26 Žilina, Slovakia.

Reliability is one of the most significant requirements for structures given in Eurocodes. Thus, the specific level of safety, serviceability, and durability have to be satisfied to fulfill the reliability of structures. In the case of reinforced concrete (RC) members, the corrosion of reinforcement is not assumed in the stage of structure design, which is in contrast with the structures in service, where the corrosion of reinforcement can significantly decrease their diameter ø in time. Read More

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Building health workforce capacity for planning and monitoring through the Strengthening Technical Assistance for routine immunization training (START) approach in Uganda.

Vaccine 2019 05 15;37(21):2821-2830. Epub 2019 Apr 15.

Centers for Disease Control and Prevention, 1600 Clifton Rd NE, Atlanta, Georgia 30329, United States. Electronic address:

Introduction: The Global Vaccine Action Plan identifies workforce capacity building as a key strategy to achieve strong immunization programs. The Strengthening Technical Assistance for Routine Immunization Training (START) approach aimed to utilize practical training methods to build capacity of district and health center staff to implement routine immunization (RI) planning and monitoring activities, as well as build supportive supervision skills of district staff.

Methods: First implemented in Uganda, the START approach was executed by trained external consultants who used existing tools, resources, and experiences to mentor district-level counterparts and, with them, conducted on-the-job training and mentorship of health center staff over several site visits. Read More

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Durability of Polymer Metal Multilayer: Focus on the Adhesive Chemical Degradation.

Front Chem 2018 22;6:459. Epub 2018 Nov 22.

Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP, LEPMI, Grenoble, France.

Mechanical toughness and high barriers to air and water may be combined in a polymer-metal multilayer film, provided that the two materials are properly bonded together. Delamination is indeed the most severe flaw observed in service. This suggests that the polyurethane (PU) adhesive at the polymer-metal interface fails to bear the shear forces, as happens principally if a multilayer system is submitted to elevated temperature and humidity. Read More

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November 2018

CNT/polymer interface in polymeric composites and its sensitivity study at different environments.

Adv Colloid Interface Sci 2017 Feb 28;240:77-106. Epub 2016 Dec 28.

Composite Materials Group, Metallurgical and Materials Engineering, National Institute of Technology, Rourkela 769008, India. Electronic address:

The environmental durability of polymer based composites has always been a critical concern over its short- and long-term performances. The degree of environmental degradation is supposed to have different mechanisms and kinetics at the polymer/reinforcement interfaces in comparison to the bulk polymer matrix. Differential degradation could possibly attribute a stressed state in the material, especially at the interfaces. Read More

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February 2017

Orthotic management of instability of the knee related to neuromuscular and central nervous system disorders: systematic review, qualitative study, survey and costing analysis.

Health Technol Assess 2016 07;20(55):1-262

Kingston University and St George's University of London, London, UK.

Background: Patients who have knee instability that is associated with neuromuscular disease (NMD) and central nervous system (CNS) conditions can be treated using orthoses, such as knee-ankle-foot orthoses (KAFOs).

Objectives: To assess existing evidence on the effectiveness of orthoses; patient perspectives; types of orthotic devices prescribed in the UK NHS; and associated costs.

Methods: Qualitative study of views of orthoses users - a qualitative in-depth interview study was undertaken. Read More

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Assessment of an action against environmental noise: Acoustic durability of a pavement surface with crumb rubber.

Sci Total Environ 2016 Jan 28;542(Pt A):223-30. Epub 2015 Oct 28.

University of Castilla-La Mancha, Laboratory of Acoustics Applied to Civil Engineering, Avda. Camilo José Cela s/n, 13071 Ciudad Real, Spain. Electronic address:

Environmental noise is a worldwide problem that has an adverse effect in the quality of life of urban population. Some work has shown that there is a correlation between environmental noise and health issues as sleep disturbance or annoyance. This study presents the time evolution of a test track fabricated with an asphalt mixture with 20% of crumb rubber by weight of bitumen, added by the wet process. Read More

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January 2016

Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

Sensors (Basel) 2015 Jul 30;15(8):18666-713. Epub 2015 Jul 30.

Department of Industrial Engineering-DIN, University of Bologna, Forlì 47121, Italy.

In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. Read More

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A testing platform for durability studies of polymers and fiber-reinforced polymer composites under concurrent hygrothermo-mechanical stimuli.

J Vis Exp 2014 Dec 11(94). Epub 2014 Dec 11.

Department of Mechanical and Aerospace Engineering, University of California, Davis;

The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs and condition-based maintenance. These materials are adopted in a wide range of engineering applications, from aircraft and ship structures, to bridges, wind turbine blades, biomaterials and biomedical implants. Polymers are viscoelastic materials, and their response may be highly nonlinear and thus make it challenging to predict and monitor their in-service performance. Read More

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December 2014

Fullerene embedded shape memory nanolens array.

Sci Rep 2013 Nov 20;3:3269. Epub 2013 Nov 20.

1] Research Institute of Advanced Materials (RIAM), Department of Materials Science and Engineering, Seoul National University, Daehak-Dong, Gwanak-Gu, Seoul 151-744, Korea [2].

Securing fragile nanostructures against external impact is indispensable for offering sufficiently long lifetime in service to nanoengineering products, especially when coming in contact with other substances. Indeed, this problem still remains a challenging task, which may be resolved with the help of smart materials such as shape memory and self-healing materials. Here, we demonstrate a shape memory nanostructure that can recover its shape by absorbing electromagnetic energy. Read More

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November 2013

A retrospective study on the long-term placement of peripherally inserted central catheters and the importance of nursing care and education.

Cancer Nurs 2011 Jan-Feb;34(1):E25-30

Department of Diagnostic Radiology, Taipei Medical University Hospital, Taipei, Taiwan.

Background: Peripherally inserted central catheters (PICCs) have been used for years in Taiwan, but their broad usage has been restricted by their short durability and complications.

Objective: The aim of this study was to evaluate the most important factors causing failure of PICCs by comparing 2 periods of retrospectively studied cases before and after we implemented nursing care improvements.

Methods: We analyzed possible factors affecting the length of the insertion period, according to the reasons for catheter withdrawal after insertion, self-care ability, coagulation status, and other factors. Read More

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Reciprocal peer management: Improving staff instruction in a vocational training program.

Authors:
R Fleming

J Appl Behav Anal 1992 ;25(3):611-20

Auburn University.

To test the feasibility and utility of involving peers as sources of feedback, 6 subjects, instructors in a vocational program for adults with mental retardation, participated in a staff training and management program. Subjects' teaching interactions were assessed during baseline, in-service training (on effective teaching), return-to-baseline, peer management, and follow-up phases. Peer management was introduced in multiple baseline fashion across pairs of subjects. Read More

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Fracture mechanics principles applied to implant medical devices--a review.

Med Prog Technol 1988-1989;14(3-4):193-203

U.S. Food & Drug Administration, Center for Devices and Radiological Health, Rockville, MD 20852.

Historically, the fatigue behavior of materials and structures, including biomaterials and implant devices, was analyzed using stress-life (S-N) techniques, i.e. by determining the number of cycles to failure at a calculated peak stress. Read More

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November 1989

Durability of innovations: how goal attainment scaling programs fare over time.

Community Ment Health J 1980 ;16(2):130-43

Why do some implementations in human service settings of goal attainment scaling (GAS), an innovative program evaluation technique, last over time, whereas others die out despite an initially successful period of operation? To provide some tentative answers to this question and to help shed more light generally on differences between sustained and nonsustained innovative programs in service delivery organizations, 10 intensive case studies were conducted. Four were goal attainment scaling programs that have proved durable over time in their host organizations versus six other programs in which goal attainment scaling did not survive despite some initial success. These case studies were analyzed both clinically and by means of expert judges' ratings to identify some of the critical variables that seem to be associated with durability of the goal attainment scaling programs. Read More

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September 1980
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