WorldWideScience

Sample records for amenagement durables prevention

  1. Opinion presented on the behalf of sustainable development and land planning commission on the finance bill for 2012. Volume 1: Ecology, sustainable development and planning: protection of the environment and risk prevention; Avis presente au nom de la Commission du Developpement Durable et de l'Amenagement du Territoire sur la loi de finances pour 2012 (n. 3775),Tome 1 Ecologie, Developpement et Amenagement Durables: protection de l'environnement et prevention des risques

    Energy Technology Data Exchange (ETDEWEB)

    Priou, Ch.

    2011-07-01

    This author first reports the examination of credits asked for 2012 for a 'risk prevention' program. This program comprises prevention and struggle regarding natural and hydraulic hazards, prevention and struggle regarding technological and pollution hazards, and health and environment policies. Then, he reports the examination of credits asked for 2012 for a 'Meteo-France' program. He discusses the program structure and the asked credits, the Meteo-France budget situation, and the new objectives. He does the same for a 'geographic and cartographic information' program for which he discusses the program structure and the asked credits, the strategic orientations, and the progress status in the building up of a large scale referential

  2. Report realized in the name of the finances, economy and the plan commission on the project of financing law for 2009 (n. 1127), annex n. 13 ecology, sustainable development and management risks prevention planing of the ecology, the energy, the sustainable development and the territory management policies; Rapport fait au nom de la commission des finances, de l'economie generale et du plan sur le projet de loi de finances pour 2009 (n. 1127), annexe n. 13 ecologie, developpement et amenagement durables prevention des risques conduite et pilotage des politiques de l'ecologie, de l'energie, du developpement durable et de l'amenagement du territoire

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This document presents the law project n. 1127 for 2009, concerning the risks prevention in the framework of the ecology and the sustainable development and management. The first part details the program of risks prevention (technological, pollutions, natural and hydraulic risks, nuclear safety and radioprotection, the mine site rehabilitation). The second part develops the ecology, energy sustainable development and territory management, policies. (A.L.B.)

  3. Report on the behalf of the Finance, General Economy and Budgetary Control Commission on the Finance bill for 2011 (n. 2824), appendix N. 13: ecology, sustainable development and land planning, hazard prevention, management and steering of ecology, energy, sustainable development, land planning and sea policies; Rapport fait au nom de la Commission des Finances, de L'economie Generale et du Controle Budgetaire sur le projet de loi de finances pour 2011 (n. 2824), annexe N. 13 ecologie, developpement et amenagement durables prevention des risques conduite et pilotage des politiques de l'ecologie, de l'energie, du developpement durable et de la mer

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    This report comments the grants awarded to two programmes, the first one concerning the prevention of hazards, and the second concerning the management and steering of ecology, energy, sustainable development, land planning and sea policies. These two programmes are emblematic of the French government's action and ambition in the field of sustainable development and ecology. For the first one, the report comments the evolution of grants, their objectives and performance indicators. Then it addresses its various aspects: prevention of technological hazards and pollutions, prevention of natural and hydraulic hazards, nuclear safety, after-mine management. For the second programme, the report gives an assessment of the ministry reorganization, and comments the means requested for 2011

  4. Durable ?

    OpenAIRE

    Joumard, R.

    2011-01-01

    L'expression développement durable est souvent vidée de toute signification. Cet ouvrage cherche donc à clarifier le sens de l'adjectif durable et du concept de développement durable. Quelle est l'histoire occidentale du développement durable ? Comment définir précisément les dimensions de celui-ci et leurs relations ? Que signifient environnement, social, besoins, long terme, gouvernance ? Dans quelle mesure croissance et développement durable sont-ils compatibles ? Comment le développement ...

  5. Durability investigation of Calvaria Bridge and electrochemical realkalinisation as a preventive measure

    Directory of Open Access Journals (Sweden)

    Meda NEDELCU

    2014-12-01

    Full Text Available The purpose of this study is to investigate the performance of reinforced concrete structures during their service life. Environmental attacks, such as the atmospheric carbon dioxide and the deicing chloride salts ingression, may seriously affect both the concrete section and the embedded reinforcement and may lead to failure, if immediate measures are not taken. Therefore, a case study of a real structure, the Calvaria Bridge, an intense traffic node in Cluj-Napoca, Romania, was performed, with emphasis on the effects of durability aspects on the structural performance of the elements, namely in terms of deflection. A modern repair method, electrochemical realkalinisation, was also tested in the laboratory, in order to provide a proper intervention solution to the structure, for the concrete elements affected by the ingress of carbon dioxide and thus, by carbonation.

  6. Notice presented in the name of the economical affairs, the environment and the territory commission, on the financial law project for 2009 (n. 1127), part 2 ecology, sustainable development and management. volume 1 environment and energy; Avis presente au nom de la commission des affaires economiques, de l'environnement et du territoire sur le projet de loi de finances pour 2009 (n. 1127), tome 2 ecologie, developpement et amenagement durables. volume 1 environnement et energie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This law document concerns the evaluation and analysis of the demanded credits for 2009 (the increase of the credits in the risks prevention, the energy supply in the framework of the climatic change) and the supply of the energy in a context of the environmental quality (the renewable energies development, the electric power production and consumption, the nuclear energy future). (A.L.B.)

  7. Concrete durability

    Directory of Open Access Journals (Sweden)

    Gaspar Tébar, Demetrio

    1991-03-01

    Full Text Available The evidence that the concrete is not a material for ever was noticed from the beginning of its industrial use. In the present work, the author describes the studies carried out during the last century and the early ages of the present one, mainly devoted to the study of the durability in sea water. At the present days, and in spite of the numerous papers published from then, the study of the concrete durability continues focusing the research priorities and economical resources of researchers and industries related with this material. Moreover, the new laboratory techniques are allowing to understand old problems and even to open again the discussion on reaction mechanisms which were believed to be completely understood. The article finalizes with a brief description of the numerous studies carried out at the Institute Eduardo Torroja on concrete durability, mainly those related with the resistance against gypsum attack (so abundant in our country land and against sea water attack.

    La realidad de que el hormigón no es un material eterno y es susceptible de sufrir ataques por agentes químicos, fue constatada desde el comienzo mismo de su uso industrial. En el presente trabajo el autor enumera los estudios realizados el siglo pasado y a comienzos del presente sobre la durabilidad del hormigón en agua de mar. En la actualidad y a pesar de los numerosos trabajos desarrollados desde entonces, el estudio de la durabilidad del hormigón sigue centrando la atención prioritaria y los recursos económicos de los investigadores e industrias relacionadas con este material. Además las nuevas técnicas de estudio están permitiendo comprender antiguos problemas e incluso reabrir la discusión sobre mecanismos de reacción que se creían completamente explicados. Finaliza el artículo con una descripción somera de los múltiples trabajos realizados en el Instituto Eduardo Torreja sobre la materia, en especial los estudios realizados sobre

  8. Designing concrete for durability

    OpenAIRE

    Boyd, A.J.; Mindess, S.; Skalny, J.

    2001-01-01

    Some of the factors affecting the durability of modern concrete structures are discussed, with an emphasis on the problems caused by modern portland cements. This is followed by a description of some concrete durability issues of current interest, such as plastic shrinkage, seawater attack, and sulfate attack. The strategies for testing for durability are also discussed. It is concluded that, to produce durable concretes, a holistic approach to concrete construction must be adopted.
    ...

  9. Etude des defauts apparaissant dans les amenagements interieurs des avions d'affaires

    Science.gov (United States)

    Charette, Emilie

    The evolution of the aeronautic industry led to the development of new materials for these high performance applications. Among other examples, composite sandwich structures are increasingly used for interior body panels of business airplanes. These structures are assembled and fixed to the fuselage using metallic inserts bonded inside the sandwich panels with an epoxy resin adhesive. A thin film of wood veneer covers the visible side of interior furniture in order to bring sophistication and esthetic to the interior design. However, due to multiple factors, surface defects frequently appear on the veneered side of the panel where inserts are located. Moreover the defects tend to appear months after the airplane delivery causing costly reparations. The sources of defects can be mechanical ( deformation due to an excessive tightening), chemical (shrinkage of the epoxy adhesive) or the result of hygrothermal exposition. It is therefore important to understand the source of such surface defects and ultimately prevent or control their appearance. The present thesis deals with defects from chemical and hygrothermal sources appearing on the composite panels used on the interior body of business jets after aging. The main objective was to identify and quantify phenomena causing the defects on the interior panels of business planes. This research project is the first part of a project sponsored by CRIAQ and NSERC. The interaction of several materials can lead to various phenomena causing the apparition of surface defects. The project was thus divided into three parts in order to study an increasingly complex problem. the first study deals with the characterization of the different constitutive materials taken separately. This first part focused on thermal, rheological and mechanical aspects of epoxy adhesives. It was shown that the two adhesives used have different mechanical properties and cure kinetic reactions. In addition, the mechanical properties of sandwich

  10. Designing concrete for durability

    Directory of Open Access Journals (Sweden)

    Boyd, A. J.

    2001-12-01

    Full Text Available Some of the factors affecting the durability of modern concrete structures are discussed, with an emphasis on the problems caused by modern portland cements. This is followed by a description of some concrete durability issues of current interest, such as plastic shrinkage, seawater attack, and sulfate attack. The strategies for testing for durability are also discussed. It is concluded that, to produce durable concretes, a holistic approach to concrete construction must be adopted.

    Se discuten algunos de los factores que influyen en la durabilidad de las estructuras de hormigón modernas, haciendo énfasis en los problemas causados por el cemento Portland. A esto sigue una descripción de algunas cuestiones de interés general de la durabilidad del hormigón tales como la retracción plástica, el ataque por agua de mar y el ataque por sulfatos. Se discuten también las estrategias de los ensayos de durabilidad. Se concluye que para producir hormigones durables se debe adoptar un enfoque holístico de la construcción con hormigón.

  11. Durable superoleophobic polypropylene surfaces.

    Science.gov (United States)

    Brown, Philip S; Bhushan, Bharat

    2016-08-01

    Polypropylene (PP) is a popular plastic material used in consumer packaging. It would be desirable if such plastic containers were liquid repellent and not so easily fouled by their contents. Existing examples of superoleophobic surfaces typically rely on poorly adhered coatings or delicate surface structures, resulting in poor mechanical durability. Here, we report a facile method for creating superoleophobic PP surfaces via incorporation of nanoparticles (NPs) into the polymer surface. A solvent-NP-PP mixture was spin coated at high temperature to achieve the necessary roughness. Such surfaces were further functionalized with fluorosilane to result in a durable, super-repellent surface. They were also found to exhibit some repellency towards shampoos. This method of incorporating NPs into polymer surfaces could also prove useful in improving the anti-bacterial, mechanical and liquid-repellent properties of plastic devices.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. PMID:27354730

  12. Chemical durability of zircon

    Science.gov (United States)

    Trocellier, Patrick; Delmas, Robert

    2001-07-01

    Zircon (ZrSiO 4) exhibits a strong structural affinity for uranium and thorium together with a very high chemical durability. This makes it a potential crystalline host matrix to immobilize actinides issued from separation of nuclear wastes. Irradiation induces amorphization of the crystalline structure (the metamictization process) and thus may decrease the chemical durability of the material. Leaching tests have been conducted on natural zircons from Brazil and Madagascar at 96°C for a period of 1 month, using deionized water. Leachates have been analysed by inductively coupled plasma mass spectrometry (ICP-MS) and UV-visible spectrophotometry. Zircon solid surfaces have been investigated by coupling scanning electron microscopy and X-ray microanalysis (SEM-EDX) with nuclear microprobe analysis ( μPIXE, μRBS and μERDA). From the mass balance between leachates and hydrated surfaces, the probable mechanisms of zircon aqueous alteration are presented and discussed.

  13. Chemical durability of zircon

    International Nuclear Information System (INIS)

    Zircon (ZrSiO4) exhibits a strong structural affinity for uranium and thorium together with a very high chemical durability. This makes it a potential crystalline host matrix to immobilize actinides issued from separation of nuclear wastes. Irradiation induces amorphization of the crystalline structure (the metamictization process) and thus may decrease the chemical durability of the material. Leaching tests have been conducted on natural zircons from Brazil and Madagascar at 96 deg. C for a period of 1 month, using deionized water. Leachates have been analysed by inductively coupled plasma mass spectrometry (ICP-MS) and UV-visible spectrophotometry. Zircon solid surfaces have been investigated by coupling scanning electron microscopy and X-ray microanalysis (SEM-EDX) with nuclear microprobe analysis (μPIXE, μRBS and μERDA). From the mass balance between leachates and hydrated surfaces, the probable mechanisms of zircon aqueous alteration are presented and discussed

  14. Prevention

    DEFF Research Database (Denmark)

    Halken, S; Høst, A

    2001-01-01

    , breastfeeding should be encouraged for 4-6 months. In high-risk infants a documented extensively hydrolysed formula is recommended if exclusive breastfeeding is not possible for the first 4 months of life. There is no evidence for preventive dietary intervention neither during pregnancy nor lactation....... Preventive dietary restrictions after the age of 4-6 months are not scientifically documented....

  15. Low Cost, Durable Seal

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, George; Parsons, Jason; Friedman, Jake

    2010-12-17

    Seal durability is critical to achieving the 2010 DOE operational life goals for both stationary and transportation PEM fuel cell stacks. The seal material must be chemically and mechanically stable in an environment consisting of aggressive operating temperatures, humidified gases, and acidic membranes. The seal must also be producible at low cost. Currentlyused seal materials do not meet all these requirements. This project developed and demonstrated a high consistency hydrocarbon rubber seal material that was able to meet the DOE technical and cost targets. Significant emphasis was placed on characterization of the material and full scale molding demonstrations.

  16. Environmental durability of ceramics and ceramic composites

    Science.gov (United States)

    Fox, Dennis S.

    1992-01-01

    An account is given of the current understanding of the environmental durability of both monolithic ceramics and ceramic-matrix composites, with a view to the prospective development of methods for the characterization, prediction, and improvement of ceramics' environmental durability. Attention is given to the environmental degradation behaviors of SiC, Si3N4, Al2O3, and glass-ceramic matrix compositions. The focus of corrosion prevention in Si-based ceramics such as SiC and Si3N4 is on the high and low sulfur fuel combustion-product effects encountered in heat engine applications of these ceramics; sintering additives and raw material impurities are noted to play a decisive role in ceramics' high temperature environmental response.

  17. Durability of critical infrastructures

    Directory of Open Access Journals (Sweden)

    Raluca Pascu

    2011-08-01

    Full Text Available The paper deals with those infrastructures by which world society, under the pressure ofdemographic explosion, self-survives. The main threatening comes not from terrorist attacks, but fromthe great natural catastrophes and global climate change. It’s not for the first time in history when suchmeasures of self-protection are built up. First objective of this paper is to present the background fordurability analysis. Then, with the aid of these mathematical tools the absolute durability of three linearmodels, typical for critical infrastructures, are successively calculated. In order to enhance the durabilityof critical infrastructures the solution based on redundancies is chosen. Five types of connection theredundancies for each of the three models are considered. Three topological schemes for connecting theredundancies are adopted: locally, by twining and globally. Absolute values of durability in all fifteenmodels with redundancies are further calculated. Then, the relative performances of enhanced durabilityin the same fifteen models, compared with the three original models, considered as references, areanalysed. The relative costs of the same fifteen models and in similar topologic conditions are furtheranalysed. By dividing the performance with cost the relative profitableness of each model is obtained.Finally, the three initial models, each reshaped with redundancies in three selective modes, arecompared from the perspective of their relative profitableness. The outcomes of this paper are original.They are of practical interests in planning the maintenance programs and checking the plausibility ofproposed interventions according to the clause 7.4 of ISO 13822:2001

  18. Urban Decline and Durable Housing

    OpenAIRE

    Edward L. Glaeser; Joseph Gyourko

    2005-01-01

    Most of America’s largest cities in 1950 have declined since then. In these declining areas, most homes cost less than the cost of new construction. In 1990, nearly 60 percent of all owner-occupied single-unit residences in Midwest central cities were valued at less than the cost of construction. Indeed, these declining cities appear to persist because of the durability of housing. We present a durable housing model that explains a number of facts about urban dynamics. Housing durability expl...

  19. Concrete durability with antigraffiti protection

    OpenAIRE

    Neto, Elsa; Souto, Ana; Camões, Aires; Begonha, Arlindo; Cachim, Paulo

    2014-01-01

    The heritage of fair-faced concrete, largely built in the twentieth century and nowadays recognized as heritage to be protected, is susceptible to attacks by graffiti. Durability of concrete depends on the composition and characteristics of the surface, whereby it is essential to study the effects of anti-graffiti protection systems on the durability of concrete and adopt the appropriate methodology to preserve this heritage. Thus, an experimental program was developed for analyzing changes i...

  20. Improving durability through probabilistic design

    OpenAIRE

    Ferreira, Rui Miguel

    2006-01-01

    In order to obtain a more controlled durability and long-term performance of concrete structures in chloride containing environment special care is needed in the design phase of reinforced concrete structures. The recent development of probability-based procedures has proven to give a more realistic basis for both durability design and condition assessment of reinforced concrete structures. Although there is still a lack of relevant data, this approach has been successfully applied to several...

  1. The durability of Synroc

    International Nuclear Information System (INIS)

    Polished specimens of well characterised Synroc ( a polyphase titanate ceramic designed to immobilise high-level nuclear waste) containing 10 wt% simulated (PW-4b-D) waste were subjected to MCC-2 type dissolution tests at 150deg C in doubly deionised water (surface area to volume ratio 0.01 ± 0.0005 mm-1) for periods of up to 532 d. Scanning electron microscopy (SEM) of the polished surfaces and transverse sections confirmed that Synroc is highly durable and suffers little corrosion even after 532 d in doubly deionised water at 150deg C (corrosion of the least resistant major phase, perovskite, was < 0.2 μm deep, i.e. less than half the size of a grain). Many of the features observed by SEM and a large percentage of the elements released into leachants result from the dissolution of minor phases which constitute < 5 wt% of Synroc and contain a small proportion of the waste. Analysis of leachates showed that the percentages of the initial amounts of Al, Ba, Ca, Ce, Cs, Mo, Nd and Sr lost from a representative sample exposed to doubly deionised water at 150deg C for a total of 337 d were 0.10, 0.017, 0.068, 0.045, 0.028, 0.093, 0.026 and 0.064, respectively. The mechanisms of Synroc dissolution are complex. Further studies on the effect of pH and Eh on dissolution mechanisms and rates are needed. (orig.)

  2. Durable consumption, saving and retirement

    DEFF Research Database (Denmark)

    Andersen, Torben M.; Hermansen, Mikkel Nørlem

    2014-01-01

    implications for retirement decisions and responses to various changes in the environment. An improvement in the possibility of freeing housing capital makes the old retire earlier (income effect) while the young plan to retire later since they increase housing demand and reduce financial savings. Considering...... welfare in stationary equilibrium, we find that a redution in wealth locking-in in durables is not necessarily welfare improving due to the effects on bequest. From a social welfare perspective, individuals tend to choose too much financial savings, too little durable acquisition and too early retirement....

  3. Credit constraints and durable consumption

    OpenAIRE

    Herrala, Risto

    2010-01-01

    I find quantitative evidence of a significant effect for credit constraints on durable consumption during a post-deregulation consumer spending spree. The effect varied markedly across age and educational groups. Young households with low levels of education displayed high sensitivity to credit conditions. In contrast, older highly educated households were relatively immune to credit market developments.

  4. Compositional threshold for Nuclear Waste Glass Durability

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Albert A. [Pacific Northwest National Lab., Richland, WA (United States); Farooqi, Rahmatullah [Pohang Univ. of Science and Technology, (Korea, Republic of); Hrma, Pavel R. [Pacific Northwest National Lab., Richland, WA (United States), Pohang Univ. of Science and Technology, (Korea, Republic of)

    2013-04-24

    Within the composition space of glasses, a distinct threshold appears to exist that separates "good" glasses, i.e., those which are sufficiently durable, from "bad" glasses of a low durability. The objective of our research is to clarify the origin of this threshold by exploring the relationship between glass composition, glass structure and chemical durability around the threshold region.

  5. Durability of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard

    The planned research will indicate, whether fibre reinforced concrete has better or worse durability than normal concrete. Durability specimens will be measured on cracked as well as uncracked specimens. Also the pore structure in the concrete will be characterized.Keywords: Fibre reinforced...... concrete, durability, pore structure, mechanical load...

  6. Durability of GFRP reinforcing bars and their bond in concrete

    OpenAIRE

    ROLLAND, Arnaud; Chataigner, Sylvain; QUIERTANT, Marc; Benzarti, Karim; Argoul, Pierre

    2015-01-01

    The use of composite reinforcing bars (rebars) for the reinforcement of concrete appears as an attractive solution to prevent corrosion, which is the main pathology encountered on concrete structures. Although such rebars are being used for more than ten years, there is a clear lack of knowledge regarding their durability, especially under alkaline environment. This paper aims at investigating the evolutions of tensile properties and bond in concrete of GFRP (Glass Fiber Reinforced Polymer...

  7. Durability of building materials and components

    CERN Document Server

    Delgado, JMPQ

    2013-01-01

    Durability of Building Materials and Components provides a collection of recent research works to contribute to the systematization and dissemination of knowledge related to the long-term performance and durability of construction and, simultaneously, to show the most recent advances in this domain. It includes a set of new developments in the field of durability, service life prediction methodologies, the durability approach for historical and old buildings, asset and maintenance management and on the durability of materials, systems and components. The book is divided in several chapters that intend to be a resume of the current state of knowledge for benefit of professional colleagues.

  8. Segmentation in Consumer Durables Markets

    OpenAIRE

    2014-01-01

    Consumer durables markets are often observed to be segmented, with some firms producing highly reliable output and offering good warranty deals, while others produce less reliable output and offer less attractive warranties, but charge a lower price. The model of this paper defines reliability as the objective probability of product failure, not as a characteristic of individual goods. Reliability, thus defined, is treated as a choice variable of the firm. This approach to reliability is inco...

  9. DURABILITY DESIGN FOR INDONESIAN CLIMATE

    OpenAIRE

    Irmawaty, Rita; Witanto, Hendra

    2014-01-01

    Deterioration of concrete structure is directly affected by environmental factors such as temperature, humidity, chloride ion concentration and CO2 concentration, which will vary depending on the location and level of exposure to the structures. Increased humidity may increase carbonation. On the other hand, the severity of marine exposure varies considerable depending on factors such as climate, location related to the sea and structural consideration. Since durability is a major concern for...

  10. CODSTRAN: Composite durability structural analysis

    Science.gov (United States)

    Chamis, C. C.; Smith, G. T.

    1978-01-01

    CODSTRAN (COmposite Durability STRuctural ANalysis) is an integrated computer program being developed for the prediction of defect growth and fracture of composite structures subjected to service loads and environments. CODSTRAN is briefly described with respect to organization, capabilities and present status. Application of CODSTRAN current capability to a flat composite laminate with a center slit which was subjected to axial tension loading predicted defect growth which is in good agreement with C-scan ultrasonic test records.

  11. Durability of expanded polystyrene mortars

    OpenAIRE

    Ferrándiz Mas, Verónica; García Alcocel, Eva María

    2013-01-01

    The influence of the addition of various types and various concentrations of expanded polystyrene foam (both commercial and recycled) on the durability of Portland cement mortars is studied. In particular, the microstructure is studied utilizing the following methods: capillary absorption of water, mercury intrusion porosimetry, impedance spectroscopy and open porosity. In addition, the effects of heat cycles and freeze–thaw cycles on compressive strength are examined. Scanning electron micro...

  12. HMA Pavement Performance and Durability

    OpenAIRE

    del Pilar Vivar, Eliana; Haddock, John E.

    2006-01-01

    It has long been argued that at densities higher than approximately 92 percent (air void contents lower than 8 percent), a hotmix asphalt mixture is impermeable to water. However, as densities become lower (air void contents higher) than this, small decreases in the density can yield exponential increases in permeability. The objectives of this study were to better understand the increases in hot-mix asphalt pavement performance and durability that can be gained by increasing the initial pave...

  13. Vers des transport environnementalement durables ?

    OpenAIRE

    Joumard, R.

    2002-01-01

    Nous listons les différents impacts sur l'environnement et évaluons leurs évolutions depuis quelques décennies. Contrairement à cette évolution 'physique' parfois positive, la perception sociale des impacts est systématiquement croissante. La problématique environnementale peut alors être considérée comme une tentative de recréer un lien fondamental avec la nature, un nouvel ordre qui trouve une expression assez aboutie dans le concept de développement durable. Parallèlement nous présentons l...

  14. Vers des transport environnementallement durables ?

    OpenAIRE

    Joumard, Robert

    2002-01-01

    Nous listons les différents impacts sur l'environnement et évaluons leurs évolutions depuis quelques décennies. Contrairement à cette évolution 'physique' parfois positive, la perception sociale des impacts est systématiquement croissante. La problématique environnementale peut alors être considérée comme une tentative de recréer un lien fondamental avec la nature, un nouvel ordre qui trouve une expression assez aboutie dans le concept de développement durable. Parallèlement nous présentons l...

  15. Durability Environmental Regionalization for Concrete Structures

    OpenAIRE

    Daming Luo; Yan Wang; Ditao Niu

    2013-01-01

    Environment is the external factor that affects the durability of concrete structures. Buildings in different regions with different climates will respond to durability deterioration in different ways. For macroenvironmental regionalization, the dominant factor analysis method of the climatic zonation was applied into the environmental regionalization in this paper. Based on the environmental characteristics in China and the effect of environmental factor on the durability of concrete structu...

  16. Verification of durability of novel applications

    OpenAIRE

    Bragança, L.; Koukkari, Heli

    2006-01-01

    Durability of structural concrete can be assessed according to standards, when the degradation models of materials and their combinations as well as experiences from the use are available in a reliable way. In the case of innovative structural materials and applications, the needs to verify durability may lead to extensive studies on the application of current methods. A state-of-the-art of durability verification of functional concrete materials and steel-concrete composite structures shows ...

  17. Monitoring the durability of marine concrete structures

    OpenAIRE

    Tzoura, Effrosyni; Basheer, Muhammed; Nanukuttan, Sreejith; McPolin, Daniel; McCarter, John; Grattan, Kenneth; Sun, Tong; Srinivasan, Sudarsan

    2016-01-01

    New techniques based on embedded sensors have been developed for monitoring reinforced concrete structures for assessing their durability, which can be used instead of the conventional non-destructive test techniques. The continuous monitoring of concrete for its durability with various types of sensors allows not only early assessment of the potential durability of structures, but also a prediction of their service life. Effrosyni Tzoura and Muhammed Basheer of University of Leeds, Sreejith ...

  18. Durability Improvements Through Degradation Mechanism Studies

    Energy Technology Data Exchange (ETDEWEB)

    Borup, Rodney L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mukundan, Rangachary [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Spernjak, Dusan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baker, Andrew M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lujan, Roger W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Langlois, David Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ahluwalia, Rajesh [Argonne National Lab. (ANL), Argonne, IL (United States); Papadia, D. D. [Argonne National Lab. (ANL), Argonne, IL (United States); Weber, Adam Z. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kusoglu, Ahmet [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shi, Shouwnen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); More, K. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Grot, Steve [Ion Power, New Castle, DE (United States)

    2015-08-03

    The durability of polymer electrolyte membrane (PEM) fuel cells is a major barrier to the commercialization of these systems for stationary and transportation power applications. By investigating cell component degradation modes and defining the fundamental degradation mechanisms of components and component interactions, new materials can be designed to improve durability. To achieve a deeper understanding of PEM fuel cell durability and component degradation mechanisms, we utilize a multi-institutional and multi-disciplinary team with significant experience investigating these phenomena.

  19. Hygrothermal Behavior, Building Pathology and Durability

    CERN Document Server

    Delgado, JMPQ

    2013-01-01

    The main purpose of this book, Hygrothermal, Building Pathology and Durability, is to provide a collection of recent research works to contribute to the systematization and dissemination of knowledge related to construction pathology, hygrothermal behaviour of buildings, durability and diagnostic techniques and, simultaneously, to show the most recent advances in this domain. It includes a set of new developments in the field of building physics and hygrothermal behaviour, durability approach for historical and old buildings and building pathology vs. durability. The book is divided in several chapters that are a resume of the current state of knowledge for benefit of professional colleagues, scientists, students, practitioners, lecturers and other interested parties to network.

  20. Experimental Study on Durability Improvement of Fly Ash Concrete with Durability Improving Admixture

    OpenAIRE

    Quan, Hong-zhu; Kasami, Hideo

    2014-01-01

    In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete,...

  1. Nuclear power and durable development

    International Nuclear Information System (INIS)

    This paper highlights the role that the nuclear power can play in a durable development of society. From a comparative analysis of different energy sources capable to fulfil the national energy demand it turns out that for Romania the optimal alternative is nuclear power. The nuclear power proved its attributes and characteristics in ensuring durable development by: 1. the technological maturation of the CANDU system as demonstrated by the good functioning of Cernavoda NPP Unit 1; 2. optimal utilization of the uranium national resources as well as the mining industry; 3. uranium processing and nuclear fuel and heavy water manufacturing as entailed by an educational infrastructure, research and industrial development; 4. low environmental impact; 5. high professional skill of the nuclear personnel. In addition, the low cost of the energy produced by the nuclear sector, as well as the social effects, namely, a 100% utilization of industrial infrastructure and national research capacity, urges the decision makers to develop the Cernavoda NPP, to increase the weight of nuclear energy in the energy production of the country

  2. Steam pipelines' effort and durability

    Directory of Open Access Journals (Sweden)

    J. Okrajni

    2007-06-01

    Full Text Available Purpose: The main problem addressed in the paper is the description of an effort and durability of steam pipelines under the conditions of mechanical and thermal interactions.Design/methodology/approach: The FEM modelling has been used to determine the stress and strain fields in the pipelines and to describe their behaviour under mechanical and thermal loading.Findings: An appropriate model description has been developed. So far, experimental verification of the usefulness of the model description to determine the stress and strain patterns in particular object and for chosen operation conditions has been made. The analysis made has shown that the most probable cause of cracks occurrence on the analyzed chosen pipeline’ inner surfaces are thermal deformations and constraints of their dislocations.Research limitations/implications: The developed description should be useful in problems of behaviour predictions of high temperature components and their durability assessment under different mechanical and thermal loadings in industry practical applications.Originality/value: The method, which more precise description of power industry components behaviour makes possible have been shown in the work. The work is addressed to researchers interested in problems of component behaviour prediction under different loadings that we can meet in the operation practice and to power industry engineering maintenance staff.

  3. ETUDE PREALABLE A L'AMENAGEMENT DE LA RESERVE FORESTIERE DE MBALMAYO (CAMEROUN) : PRATIQUES ET MODES D'ACCES DES POPULATIONS LOCALES

    OpenAIRE

    Peltier, Régis; Temgoua, Lucie Félicité

    2008-01-01

    La protection de l'environnement est devenue un enjeu planétaire durant les années 1980. Le discours international sur la gestion durable des forêts tropicales prône la nécessité d'impliquer les populations locales dans la gestion des ressources forestières et fauniques. Au Cameroun, La loi forestière de 1994 offre aux populations locales de nouvelles possibilités de développement à travers une gestion décentralisée. Tout récemment, le Ministère des Forêts et de la Faune a prévu le transfert ...

  4. DURABILITY OF HARDENED FLY ASH PASTE

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The mechanical properties and durability ( mainly frost-resistance and carbonation resistance ) of fly ash-CaO-CaSO4 .2H2O hardened paste are studied. The relationship among durability of harden ed fly ash paste, the quantity and distribution of hydrates and the initial p aste texture of hardened fly ash paste is presented.

  5. Enduring Legacy? Charles Tilly and Durable Inequality

    OpenAIRE

    Voss, Kim

    2010-01-01

    This article assesses Charles Tilly’s Durable Inequality and traces its influence. In writing Durable Inequality, Tilly sought to shift the research agenda of stratification scholars. But the book’s initial impact was disappointing. In recent years, however, its influence has grown, suggesting a more enduring legacy.

  6. Ceramics: Durability and radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, R.C.; Lutze, W. [Univ. of New Mexico, Albuquerque, NM (United States); Weber, W.J. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-05-01

    At present, there are three seriously considered options for the disposition of excess weapons plutonium: (1) incorporation, partial burn-up and direct disposal of MOX-fuel; (2) vitrification with defense waste and disposal as glass {open_quotes}logs{close_quotes}; (3) deep borehole disposal. The first two options provide a safeguard due to the high activity of fission products in the irradiated fuel and the defense waste. The latter option has only been examined in a preliminary manner, and the exact form of the plutonium has not been identified. In this paper, we review the potential for the immobilization of plutonium in highly durable crystalline ceramics apatite, pyrochlore, zirconolite, monazite and zircon. Based on available data, we propose zircon as the preferred crystalline ceramic for the permanent disposition of excess weapons plutonium.

  7. Integrated durability process in product development

    International Nuclear Information System (INIS)

    This presentation describes the integrated durability process in product development. Each of the major components of the integrated process are described along with a number of examples of how integrated durability assessment has been used in the ground vehicle industry. The durability process starts with the acquisition of loading information, either physically through loads measurement or virtually through multibody dynamics. The loading information is then processed and characterized for further analysis. Durability assessment was historically test based and completed through field or laboratory evaluation. Today, it is common that both the test and CAE environments are used together in durability assessment. Test based durability assessment is used for final design sign-off but is also critically important for correlating CAE models, in order to investigate design alternatives. There is also a major initiative today to integrate the individual components into a process, by linking applications and providing a framework to communicate information as well as manage all the data involved in the entire process. Although a single process is presented, the details of the process can vary significantly for different products and applications. Recent applications that highlight different parts of the durability process are given. As well as an example of how integration of software tools between different disciplines (MBD, FE and fatigue) not only simplifies the process, but also significantly improves it. (author)

  8. Highly Dispersed Alloy Catalyst for Durability

    Energy Technology Data Exchange (ETDEWEB)

    Murthi, Vivek S.; Izzo, Elise; Bi, Wu; Guerrero, Sandra; Protsailo, Lesia

    2013-01-08

    Achieving DOE's stated 5000-hr durability goal for light-duty vehicles by 2015 will require MEAs with characteristics that are beyond the current state of the art. Significant effort was placed on developing advanced durable cathode catalysts to arrive at the best possible electrode for high performance and durability, as well as developing manufacturing processes that yield significant cost benefit. Accordingly, the overall goal of this project was to develop and construct advanced MEAs that will improve performance and durability while reducing the cost of PEMFC stacks. The project, led by UTC Power, focused on developing new catalysts/supports and integrating them with existing materials (membranes and gas diffusion layers (GDLs)) using state-of-the-art fabrication methods capable of meeting the durability requirements essential for automotive applications. Specifically, the project work aimed to lower platinum group metals (PGM) loading while increasing performance and durability. Appropriate catalysts and MEA configuration were down-selected that protects the membrane, and the layers were tailored to optimize the movements of reactants and product water through the cell to maximize performance while maintaining durability.

  9. L’examen méthodique d’un geste de métier pour une prévention durable des TMS : une intervention en clinique de l’activité Methodological examination of job-related body movements for the sustainable prevention of msds: a clinical intervention on the activity El examen metódico de un gesto de oficio por une prevención durable des LMS : une interpretación en clínica de la actividad

    Directory of Open Access Journals (Sweden)

    Pascal Simonet

    2009-11-01

    Full Text Available L’intervention sur laquelle s’appuie cet article a été initiée par un service de médecine préventive qui souhaite étendre ses actions de prévention durable des TMS. Elle a été conduite selon les principes méthodologiques de la clinique de l’activité dans la perspective d’ouvrir les corps porteurs de douleurs déclarées sur un autre destin que celui de la réalisation de la pathologie. Les observations prolongées et répétées des activités concrètes de travail transforment les sujets observés en observateurs de leur activité. Le cadre des autoconfrontations simples et croisées a pour fonction de soutenir les efforts d’élaboration des professionnels à partir de dialogues entre eux. Les controverses professionnelles qui trouvent parfois à s’y réaliser enrichissent les connaissances et l’expertise de chacun dans le métier. Cet article souhaite interroger les ressorts méthodologiques de la prévention des TMS en posant, notamment, la question du protagoniste de la prévention ou encore celle, associée, de la place du collectif de métier comme ressource potentiellement durable d’une démarche préventive. Dans une telle perspective, les efforts de l’intervenant portent sur les méthodes à engager pour conduire les professionnels à se confronter, dans des cadres appropriés, à d’autres réalisations gestuelles au sein d’un collectif envisagé comme instrument psychologique de développement de leur activité.1The intervention on which this article is based was initiated by a preventive medical department wanting to extend its actions on the sustainable prevention of MSDs. The intervention was based on the activity clinic’s methodological principles from the perspective of people with reported pain having a fate other than that of pathology. Prolonged and repeated observations of the actual work activities change the observed subjects into observers of their activity. The purpose of the context of

  10. To the question of reliability and durability ballastless deck of bridge

    Directory of Open Access Journals (Sweden)

    V.V. Prystynskaya

    2012-12-01

    Full Text Available The principal causes of operational defects in bridge ballastless deck plates are considered in the article. The drawbacks of these plates construction that prevent from achieving a higher level of bridge framework reliability and durability have been analysed.

  11. Local spillovers and durable adoption: Evidence from durable consumptions in rural China

    OpenAIRE

    Rong, Zhao; Feng, Yao

    2012-01-01

    Purpose – The effects of social learning and network externalities in the diffusion of a new product imply that there should be local spillovers from existing owners to new adopters in a closely-related community. Using the 1999 durable consumption survey data in rural China, this paper examines the importance of local spillovers in the diffusion of two major durable goods, washing machine and refrigerator. Design/methodology/approach – Based on an October 1999 survey of rural durable good...

  12. Durable Dust Repellent Coating for Metals Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Durable Dust Repellent Coating (DDRC) consists of nano-phase silica, titania, or other oxide coatings to repel dust in a vacuum environment over a wide range of...

  13. The prospective buyer of consumer durables

    OpenAIRE

    Jonge, Leendert de; Oppedijk van Veen, Walle Melis

    1982-01-01

    In this book, an empirical investigation is reported wich aims at the specification of models of individual households’ purchase behaviour for particular consumer durable goods, such as private passenger cars and television sets. In particular, the focus is on models wich can be used for predicting ehther or not a household will make a purchase of such a durable whtin a pre-specified period. The book consists of four parts, each of wich describes a particular phase of the investigation. ... Z...

  14. Mechanistic Enhancement of SOFC Cathode Durability

    Energy Technology Data Exchange (ETDEWEB)

    Wachsman, Eric [Univ. of Maryland, College Park, MD (United States)

    2016-02-01

    Durability of solid oxide fuel cells (SOFC) under “real world” conditions is an issue for commercial deployment. In particular cathode exposure to moisture, CO2, Cr vapor (from interconnects and BOP), and particulates results in long-term performance degradation issues. Here, we have conducted a multi-faceted fundamental investigation of the effect of these contaminants on cathode performance degradation mechanisms in order to establish cathode composition/structures and operational conditions to enhance cathode durability.

  15. Credit frictions and the comovement between durable and non-durable consumption

    NARCIS (Netherlands)

    V. Sterk

    2010-01-01

    Frictions in lending between households have been proposed as a solution to the difficulties new-Keynesian models have in predicting a decline in both durable and non-durable consumption following a monetary tightening. By revisiting a standard new-Keynesian framework with collateral constraints, it

  16. Assessment of properties and durability of fly ash concrete used in Korean nuclear power plants

    International Nuclear Information System (INIS)

    Since the opening of the Shin-Kori no. 1, 2 in 2005, fly ash mixed concrete has been used for NPP concrete structures under construction in Korea with the aim of preventing aging and improving durability. In this paper, the quality suitability of fly ash manufactured in Korea is assessed and the basic physical properties of fly ash mixed concrete and its durability against primary causes of aging are verified through experimental methods. Because of the internal structure filling effect from the pozzolanic reaction of fly ash and the resulting improvements in mechanical performance in such areas as strength and salt damage resistance, the durability of fly ash mixed concrete is shown to be superior. It is judged that this result can be applied in measures not only for improving the safety of NPP structures in operation in Korea but also for implementing effective structure life management should extending the life of structures be needed in the future.

  17. A Review: Durability of Fired Clay Brick Masonry Wall due to Salt Attack

    Directory of Open Access Journals (Sweden)

    B.H. Abu Bakar

    2009-12-01

    Full Text Available This paper offers a review on durability of fired clay brick masonry wall due to salt attack. Durability of brick normally affected when an external masonry walls are exposed to aggressive environment. Masonry structures, when subjected to salt attack or exposed to aggressive environment during their service life may suffer degradation due to the formation of crystallization pressure as a result of the evaporation of soluble salt in clay masonry structures. The crystallization pressures produce normally higher than tensile stress of clay brick and sufficient to damage the masonry structures. The mechanism of salt attack must be prevented and addressed thoroughly in order to maintain the integrity and service life of masonry wall. Therefore, the summary of durability, factors, mechanism and main sources of salt attack on fired clay brick masonry walls are discussed.

  18. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    fibre reinforcement are exposed to a combination of mechanical and environmental load to indicate whether fibre reinforcement will improve the durability of cracked concrete structures. Secondly, it is the aim to identify important mechanisms for the effect of the fibre reinforcement on the durability......Durability studies are carried out at BKM as part of the research project "Design Methods for Fibre Reinforced Concrete" (FRC) involving BKM, The Concrete Research Center at DTI, Building Technology at Aalborg University, Rambøll, 4K-Beton and Rasmussen & Schiøtz. Concrete beams with or without...... pore structure are made on specimens drilled or sawed from beams after unloading (mechanical load). The pore structure of the concretes will be studied by microscopy, sorption and suction curves. The test programme involves three different concrete qualities (water-cement ratios). Both steel fibres (ZP...

  19. A generalized definition for waste form durability

    International Nuclear Information System (INIS)

    When evaluating waste form performance, the term ''durability'' often appears in casual discourse, but in the technical literature, the focus is often on waste form ''degradation'' in terms of mass lost per unit area per unit time. Waste form degradation plays a key role in developing models of the long-term performance in a repository environment, but other factors also influence waste form performance. These include waste form geometry; density, porosity, and cracking; the presence of cladding; in-package chemistry feedback; etc. The paper proposes a formal definition of waste form ''durability'' which accounts for these effects. Examples from simple systems as well as from complex models used in the Total System Performance Assessment of Yucca Mountain are provided. The application of ''durability'' in the selection of bounding models is also discussed

  20. Glass durability evaluation using multiple test methods

    International Nuclear Information System (INIS)

    The high content of Na2O in Hanford Site low-level tank wastes, averaging about 80 wt % on an oxide basis, necessitates the development of durable high-sodium glasses. Pacific Northwest Laboratory (PNL) is providing glass formulation support for this program. Glass development entails testing many glasses in a short time; it is not practical to perform long-term durability tests on every glass. The current approach on chemical durability focuses on a suite of short-term laboratory tests such as dynamic single-pass flow-through (SPFT) tests, static product consistency tests (PCT), and vapor hydration tests. The preliminary results from the three types of tests are quite different, but each provides insight into the glass corrosion process. The PCT data showed that at the same alumina, silica, and sodium levels the glass durability order for different glass systems is: Boron-only > Mixture > Calcium-only, while the opposite order is observed in SPFT tests. The order for vapor hydration tests is: Boron-only > Mixture = Calcium-only. Understanding of the glass durability order requires knowledge of the glass corrosion mechanism under specific test conditions. Integration of the three types of tests used in this program provides a more nearly complete picture of glass corrosion progress and the needed confidence for a glass optimization program. The 7-day PCT tests may provide one of the best means for preliminary screening of glass compositions within short development time. The results are relevant to long-term (or final stage corrosion) durability, as assessed by vapor hydration tests

  1. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Nielsen, Laila

    (capillary water uptake) is used, involving an in-situ method and a laboratory method. Three different concrete qualities as well as steel fibres (ZP) and polypropylene fibres (PP) are used. Results of the durability tests on cracked FRC-beams are compared to results for uncracked FRC-beams and beams without......Durability studies are carried out by subjecting FRC-beams to combined mechanical and environmental load. Mechanical load is obtained by exposing beams to il-point bending until a predefined crack width is reached, using a newly developed test setup. As environmental load, exposure to water...

  2. Probabilistic Durability Analysis in Advanced Engineering Design

    Directory of Open Access Journals (Sweden)

    A. Kudzys

    2000-01-01

    Full Text Available Expedience of probabilistic durability concepts and approaches in advanced engineering design of building materials, structural members and systems is considered. Target margin values of structural safety and serviceability indices are analyzed and their draft values are presented. Analytical methods of the cumulative coefficient of correlation and the limit transient action effect for calculation of reliability indices are given. Analysis can be used for probabilistic durability assessment of carrying and enclosure metal, reinforced concrete, wood, plastic, masonry both homogeneous and sandwich or composite structures and some kinds of equipments. Analysis models can be applied in other engineering fields.

  3. Durability of phosphate-selective CHEMFETs

    NARCIS (Netherlands)

    Wroblewski, Wojciech; Wojciechowski, Kamil; Dybko, Artur; Brzozka, Zbigniew; Egberink, Richard J.M.; Snellink-Ruel, Bianca H.M.; Reinhoudt, David N.

    2001-01-01

    Lipophilic uranyl salophenes derivatives I and II were used as ionophores in membranes of phosphate-selective CHEMFETs. High selectivity for H2PO4− over other anions was obtained for these sensors. The influence of the ionophore structure on the sensor durability was investigated. CHEMFETs based on

  4. 40 CFR 610.33 - Durability tests.

    Science.gov (United States)

    2010-07-01

    ....33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY... addition to the basic evaluation testing for device effectiveness. This requirement may be necessary for..., then a durability run may be made as described in subpart E, in which fuel economy and...

  5. Advantage from Funding Durable Centers Leasing

    Directory of Open Access Journals (Sweden)

    Alina Zając

    2009-09-01

    Full Text Available In present market conditions huge number of businessmen has problems from gain over from banks capital on purchase of durable centers not only, but also on develop - ment and operating activity Individual can use with different forms funding investment, it which is between different leasing.

  6. DURABLE GLASS FOR THOUSANDS OF YEARS

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C.

    2009-12-04

    The durability of natural glasses on geological time scales and ancient glasses for thousands of years is well documented. The necessity to predict the durability of high level nuclear waste (HLW) glasses on extended time scales has led to various thermodynamic and kinetic approaches. Advances in the measurement of medium range order (MRO) in glasses has led to the understanding that the molecular structure of a glass, and thus the glass composition, controls the glass durability by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. During the early stages of glass dissolution, a 'gel' layer resembling a membrane forms through which ions exchange between the glass and the leachant. The hydrated gel layer exhibits acid/base properties which are manifested as the pH dependence of the thickness and nature of the gel layer. The gel layer ages into clay or zeolite minerals by Ostwald ripening. Zeolite mineral assemblages (higher pH and Al{sup 3+} rich glasses) may cause the dissolution rate to increase which is undesirable for long-term performance of glass in the environment. Thermodynamic and structural approaches to the prediction of glass durability are compared versus Ostwald ripening.

  7. Prognosing the durability of polymer sealings

    Directory of Open Access Journals (Sweden)

    W. Okularczyk

    2006-04-01

    Full Text Available Purpose: The paper describes the phenomena connected with the sealing for water hydraulic systems.Design/methodology/approach: For the durability tests two types of sealings, made of three polymeric materials recommended for use in water hydraulics systems have been used. In all investigation arrangements the same guide elements have been used. The tests have been performed maintaining water pressure on the sealing at a level of p = 8±1 MPa and the average speed of the piston rod of v ≈ 0.35 m/sec. Water temperature during investigations was regulated within the range of Tmin = 291 K and Tmax = 305 K. The leakage was distributed to the measurement hoses with the internal diameter of 5mm. For the investigations, the working piston rod with ø 45 f7 with the following parameters has been used: Material: chromium-nickel steel AISI 431 (Cr=16.7%, Ni=2.08% covered with hard chromium plating of ≥ 20 μm, micro-cracks number ≤ 5 000/mm2, Ra = 0.07 μm.Findings: Weibull method, thanks to its multifunctionality, helps to select elements for certain applications (required long failure-free mileages → high characteristic durability – sealings series 30413. Equipment which works sporadically → low characteristic durability but e.g. lower weight and sizes of sealing element – sealing series 30412.Practical implications: Within the confines of the given research concerning an optimal choice of piston rod sealing for water hydraulic systems, large dependence of the sealing durability on the properly chosen guide elements of the piston rod has been found. In extreme cases the durability changed even a few times.Originality/value: The Weibull method has been applied for assessment of durability and reliability of mechanical parts. A computer program has been used to compare two types of piston rod seals used in water hydraulic power systems. Durability limits have been estimated even though discontinued measurement data were used.

  8. Quantitative risk assessment of durable glass fibers.

    Science.gov (United States)

    Fayerweather, William E; Eastes, Walter; Cereghini, Francesco; Hadley, John G

    2002-06-01

    This article presents a quantitative risk assessment for the theoretical lifetime cancer risk from the manufacture and use of relatively durable synthetic glass fibers. More specifically, we estimate levels of exposure to respirable fibers or fiberlike structures of E-glass and C-glass that, assuming a working lifetime exposure, pose a theoretical lifetime cancer risk of not more than 1 per 100,000. For comparability with other risk assessments we define these levels as nonsignificant exposures. Nonsignificant exposure levels are estimated from (a) the Institute of Occupational Medicine (IOM) chronic rat inhalation bioassay of durable E-glass microfibers, and (b) the Research Consulting Company (RCC) chronic inhalation bioassay of durable refractory ceramic fibers (RCF). Best estimates of nonsignificant E-glass exposure exceed 0.05-0.13 fibers (or shards) per cubic centimeter (cm3) when calculated from the multistage nonthreshold model. Best estimates of nonsignificant C-glass exposure exceed 0.27-0.6 fibers/cm3. Estimates of nonsignificant exposure increase markedly for E- and C-glass when non-linear models are applied and rapidly exceed 1 fiber/cm3. Controlling durable fiber exposures to an 8-h time-weighted average of 0.05 fibers/cm3 will assure that the additional theoretical lifetime risk from working lifetime exposures to these durable fibers or shards is kept below the 1 per 100,000 level. Measured airborne exposures to respirable, durable glass fibers (or shards) in glass fiber manufacturing and fabrication operations were compared with the nonsignificant exposure estimates described. Sampling results for B-sized respirable E-glass fibers at facilities that manufacture or fabricate small-diameter continuous-filament products, from those that manufacture respirable E-glass shards from PERG (process to efficiently recycle glass), from milled fiber operations, and from respirable C-glass shards from Flakeglass operations indicate very low median exposures of 0

  9. Optical durability testing of candidate solar mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.; Kennedy, C.; King, D.; Terwilliger, K.

    2000-03-24

    Durability testing of a variety of candidate solar reflector materials at outdoor test sites and in laboratory accelerated weathering chambers is the main activity within the Advanced Materials task of the Concentrated Solar Power (CSP) Program. Outdoor exposure testing (OET) at up to eight outdoor, worldwide exposure sites has been underway for several years. This includes collaboration under the auspices of the International Energy Agency (IEA) Solar Power and Chemical Energy Systems (SolarPACES) agreement. Outdoor sites are fully instrumented in terms of monitoring meteorological conditions and solar irradiance. Candidate materials are optically characterized prior to being subjected to exposure in real and simulated weathering environments. Optical durability is quantified by periodically re-measuring hemispherical and specular reflectance as a function of exposure time. By closely monitoring the site- and time-dependent environmental stress conditions experienced by the material samples, site-dependent loss of performance may be quantified. In addition, accelerated exposure testing (AET) of these materials in parallel under laboratory-controlled conditions may permit correlating the outdoor results with AET, and subsequently predicting service lifetimes. Test results to date for a large number of candidate solar reflector materials are presented in this report. Acronyms are defined. Based upon OET and AET results to date, conclusions can be drawn about the optical durability of the candidate reflector materials. The optical durability of thin glass, thick glass, and two metallized polymers can be characterized as excellent. The all-polymeric construction, several of the aluminized reflectors, and a metallized polymer can be characterized as having intermediate durability and require further improvement, testing and evaluation, or both.

  10. Influence of composite material's structure on its durability

    International Nuclear Information System (INIS)

    This article is devoted to influence of composite material's structure on its durability. The influence of volume content and the number of thermo cycles on durability of expanded-clay concrete was carried out. It was shown that volume content of needle fibre in expanded-clay concrete increased proportional to composite material's durability increase. But at the same time thermo cycles decreased the durability. Therefore, combining the needle fibre content and the number of thermo cycles it is possible to manage durability and viscosity of composite materials.

  11. Structural Properties and Mechanical Durability of Extruded Fish Feed

    DEFF Research Database (Denmark)

    Haubjerg, Anders Fjeldbo; Veje, Christian; Jørgensen, Bo Nørregaard; Simonsen, Benny; Løvgreen, Sti

    2015-01-01

    This article investigates the possible correlation between mechanical properties of fish feed pellets and their mechanical durability. Mechanical properties were obtained by texture profile analysis (TPA) and stress relaxation test (SRT) of different types of fish feed. The results were correlated...... against a conventional test of mechanical durability (DORIS, Durability On a Realistic, test). From SRT it was found that for achieving a high durability, pellets should be able to relax an applied force nonelastically. From TPA, it was found that a durable pellet should also be able to return its...

  12. Prediction of glass durability as a function of environmental conditions

    International Nuclear Information System (INIS)

    The author reports on thermodynamic model of glass durability applied to natural, ancient, and nuclear waste glasses. The durabilities of over 150 different natural and man-made glasses, including actual ancient Roman and Islamic glasses (Jalame ca. 350 A. D., Nishapur 10-11th century A. D., and Gorgon 9-11th century A.D.), have been compared. Glass durability had been shown to be a function of the thermodynamic hydration free energy. Δ Ghyd, which can be calculated from glass composition and solution pH. Using this approach, the durability of the most durable nuclear waste glasses examined was ≅106 years by comparison with the durability of the natural basalts of ≅106 years. The least durable waste glass formulations were comparable in durability to the most durable simulated medieval window glasses of ≅103 years. In this manner, the durability of nuclear waste glasses has been interpolated to be ≅106 years and no less than 103 years. Hydration thermodynamics are shown to be applicable to the dissolution of glass in various natural environments. Groundwater-glass interactions relative to geologic disposal of nuclear waste, hydration rind dating of obsidians, and/or other archeological studies can be modeled, e.g. the relative durabilities of six simulated medieval window glasses have been correctly predicted for both laboratory (one month) and burial (5 year) experiments

  13. Development and durability of SOFC stacks

    Energy Technology Data Exchange (ETDEWEB)

    Beeaff, D.; Dinesen, A.R.; Mikkelsen, Lars; Nielsen, Karsten A.; Solvang, M.; Hendriksen, Peter V.

    2004-12-01

    The present project is a part of the Danish SOFC programme, which has the overall aim of establishing a Danish production of SOFC - cells, stacks and systems for economical and environmentally friendly power production. The aim of the present project was to develop and demonstrate (on a small scale, few cells, few thousand hours) a durable, thermally cyclable stack with high performance at 750 deg. C. Good progress towards this target has been made and demonstrated at the level of stack-elements (one cell between two interconnects) or small stacks (3 5 cells). Three different stacks or stack-elements have been operated for periods exceeding 3000 hr. The work has covered development of stack-components (seals, interconnects, coatings, contact layers), establishment of procedures for stack assembly and initiation, and detailed electrical characterisation with the aims of identifying performance limiting factors as well as long term durability. Further, post test investigations have been carried out to identify possible degradation mechanisms. (BA)

  14. Estimation of cyclic durability for turbine rotors

    International Nuclear Information System (INIS)

    The paper deals with data on the effect of asymetry and cycle form on low-cycle fatigue and injurability of and 15kh1m1f rotor steels at high temperatures. It is shown that the sum of injuries from the effect of cyclic and static loads may vary within the limits of-1.2. The steels were analyzed for strength effect on their deformation kinetics and durability. It is noted that the low-cycle fatigue curves in the ''complete deformation scale-cycle number'' coordinates do not depend on the strength level, and therefore it is concluded possible to use these curves for estimating the turbine rotor material durability

  15. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Nielsen, Laila

    Durability studies are carried out by subjecting FRC-beams to combined mechanical and environmental load. Mechanical load is obtained by exposing beams to il-point bending until a predefined crack width is reached, using a newly developed test setup. As environmental load, exposure to water...... (capillary water uptake) is used, involving an in-situ method and a laboratory method. Three different concrete qualities as well as steel fibres (ZP) and polypropylene fibres (PP) are used. Results of the durability tests on cracked FRC-beams are compared to results for uncracked FRC-beams and beams without...... fibres and the influence of fibres and cracks on the water uptake is discussed....

  16. Relationship Between Construction Depreciation, Durability and Fiability

    OpenAIRE

    Adrian Şerbănoiu; Marina Verdeş

    2006-01-01

    It is estimated that within Europe the value of all structures (infrastructure and built environment) represent a value of approximately 50\\% of the national wealth of most countries. Approximately 50\\% of the expenditures in the construction industry are spent on repair, maintenance and remediation of existing structures. In the future these expenses will probably increase even more. A large proportion of these expenses are due to problems related to lacking durability of concrete structures...

  17. Durability of high volume fly ash concrete

    OpenAIRE

    Camões, Aires

    2006-01-01

    It is well known that the concrete industry has to contribute to the sustainability of construction. For this intent it is necessary to reduce the cement content without compromising the durability requirements of the concrete constructions. Therefore, large scale cement replacement in concrete by by products such as fly ash will be extremely beneficial from the overall ecological and environmental point of view. In this context, an experimental research work was carried out focused on the...

  18. Fabrication of Mechanical Durable Polysiloxane Superhydrophobic Materials

    OpenAIRE

    Mengnan Qu; Jinmei He; Sun Zhe; Kanshe Li; Xiangrong Liu; Chunxia Yu

    2015-01-01

    A mechanical durable polysiloxane superhydrophobic surface was successfully prepared by means of polymerization of silanes blending with particles. The as-prepared polysiloxane surface showed stable superhydrophobicity even after the surface underwent a long distance friction. The superhydrophobicity of the polysiloxane materials can be even slightly enhanced by the surface abrasion. The scanning electron microscopy demonstrated that the micro- and nanometer structures distributed through the...

  19. Intermediate Ethanol Blends Catalyst Durability Program

    Energy Technology Data Exchange (ETDEWEB)

    West, Brian H; Sluder, Scott; Knoll, Keith; Orban, John; Feng, Jingyu

    2012-02-01

    In the summer of 2007, the U.S. Department of Energy (DOE) initiated a test program to evaluate the potential impacts of intermediate ethanol blends (also known as mid-level blends) on legacy vehicles and other engines. The purpose of the test program was to develop information important to assessing the viability of using intermediate blends as a contributor to meeting national goals for the use of renewable fuels. Through a wide range of experimental activities, DOE is evaluating the effects of E15 and E20 - gasoline blended with 15% and 20% ethanol - on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials. This report provides the results of the catalyst durability study, a substantial part of the overall test program. Results from additional projects will be reported separately. The principal purpose of the catalyst durability study was to investigate the effects of adding up to 20% ethanol to gasoline on the durability of catalysts and other aspects of the emissions control systems of vehicles. Section 1 provides further information about the purpose and context of the study. Section 2 describes the experimental approach for the test program, including vehicle selection, aging and emissions test cycle, fuel selection, and data handling and analysis. Section 3 summarizes the effects of the ethanol blends on emissions and fuel economy of the test vehicles. Section 4 summarizes notable unscheduled maintenance and testing issues experienced during the program. The appendixes provide additional detail about the statistical models used in the analysis, detailed statistical analyses, and detailed vehicle specifications.

  20. Monitoring durability of new concrete bridge decks

    Science.gov (United States)

    Aktan, Haluk M.; Yaman, Ismail O.; Staton, John F.

    2001-08-01

    The ND durability monitoring procedure, which measures the soundness of field concrete, is based on the fundamental relationship between ultrasonic pulse velocity (UPV) and permeability of an elastic medium. An experimental study documented adequate sensitivity between UPV and concrete permeability. The durability monitoring procedure is based on a parameter developed as part of this study and called paste quality loss (PQL) which is computed from the probability density function parameters of ultrasonic pulse velocity measurements taken from standard and field concrete. For PQL computation, measurements taken on standard concrete specimens, which are made from field concrete mixture, are compared to field measurements. The verification tests on 1000 mm x 1500 mm x 230 mm lab-deck specimens indicated that the PQL parameter computed from the UPV measurements as early as the 28th day is a good predictor of soundness. The UPV measurements made at increasing age of concrete very clearly document the rapid loss of soundness of improperly cured concrete decks. Deck replacement projects on three NHS bridges were used in the implementation of durability monitoring by PQL (paste quality loss) evaluation. The respective 56-day PQL's were calculated as 15%, 31% and 9% indicating a significant variability in the three bridges.

  1. Effect Of Climatic Conditions On Durability

    Directory of Open Access Journals (Sweden)

    Ibrahem M. Al Kiki

    2013-04-01

    Full Text Available Durability is one of the most important subjects in the soil stabilization. Since there is no specifications concerned the durability of lime stabilized soils, several factors were selected to show their effects on the durability, namely: wetting, drying, freezing, thawing and slaking.The effect of each one of the above factors as well as the combined effect of two or more factors, were studied on the volume change and soil strength and weight loss of soil samples stabilized with optimum lime content except the slaking test at which soil samples stabilized with different lime content.Tests results showed that the higher the lime content the lower the slaking effect, also its found the soil strength decreased when the period of immersion or freezing increased. The strength of the lime stabilized soils decreased when subjected to the cycles of wetting and drying or to the cycles freezing and thawing. However, the  combined effect of wetting, drying, freezing and thawing has a pronounced effect on reduction of the lime stabilized clayey soil. The worst condition recorded when lime stabilized soil undergo to freezing then drying then wetting which should be avoided in the field

  2. Creep Behavior and Durability of Cracked CMC

    Science.gov (United States)

    Bhatt, R. T.; Fox, Dennis; Smith, Craig

    2015-01-01

    To understand failure mechanisms and durability of cracked Ceramic matrix composites (CMCs), Melt Infiltration (MI) SiCSiC composites with Sylramic-iBN fibers and full Chemical vapour infiltration SiCSiC composites with Sylramic-ion bombarded BN (iBN) and Hi-Nicalon -S fibers were pre-cracked between 150 to 200 megapascal and then creep and Sustained Peak Low Cycle Fatigue (SPLCF) tested at 13150 C at stress levels from 35 to 103 megapascal for up to 200 hours under furnace and burner rig conditions. In addition creep testing was also conducted on pre-cracked full Chemical vapour infiltration SiCSiC composites at 14500 C between 35 and 103 megapascal for up to 200 hours under furnace conditions. If the specimens survived the 200 hour durability tests, then they were tensile tested at room temperature to determine their residual tensile properties. The failed specimens were examined by Scanning electron microscope (SEM) to determine the failure modes and mechanisms. The influence of crack healing matrix, fiber types, crack density, testing modes and interface oxidation on durability of cracked Ceramic matrix composites (CMCs) will be discussed.

  3. Durability evaluation of reversible solid oxide cells

    Science.gov (United States)

    Zhang, Xiaoyu; O'Brien, James E.; O'Brien, Robert C.; Housley, Gregory K.

    2013-11-01

    An experimental investigation on the performance and durability of single solid oxide cells (SOCs) is under way at the Idaho National Laboratory. Reversible operation of SOCs includes electricity generation in the fuel cell mode and hydrogen generation in the electrolysis mode. Degradation is a more significant issue when operating SOCs in the electrolysis mode. In order to understand and mitigate the degradation issues in high temperature electrolysis, single SOCs with different configurations from several manufacturers have been evaluated for initial performance and long-term durability. Cells were obtained from four industrial partners. Cells from Ceramatec Inc. and Materials and Systems Research Inc. (MSRI) showed improved durability in electrolysis mode compared to previous stack tests. Cells from Saint Gobain Advanced Materials Inc. (St. Gobain) and SOFCPower Inc. demonstrated stable performance in the fuel cell mode, but rapid degradation in the electrolysis mode, especially at high current density. Electrolyte-electrode delamination was found to have a significant impact on degradation in some cases. Enhanced bonding between electrolyte and electrode and modification of the electrode microstructure helped to mitigate degradation. Polarization scans and AC impedance measurements were performed during the tests to characterize cell performance and degradation.

  4. Durability of heavyweight concrete containing barite

    International Nuclear Information System (INIS)

    The supplementary waste barite aggregates deposit in Osmaniye, southern Turkey, has been estimated at around 500 000 000 tons based on 2007 records. The aim of the present study is to investigate the durability of concrete incorporating waste barite as coarse and river sand (RS), granule blast furnace slag (GBFS), granule basaltic pumice (GBP) and ≤ 4 mm granule barite (B) as fine aggregates. The properties of the fresh concrete determined included the air content, slump, slump loss and setting time. They also included the compressive strength, flexural and splitting tensile strengths and Young's modulus of elasticity, resistance to abrasion and sulphate resistance of hardened concrete. Besides these, control mortars were prepared with crushed limestone aggregates. The influence of waste barite as coarse aggregates and RS, GBFS, GBP and B as fine aggregates on the durability of the concretes was evaluated. The mass attenuation coefficients were calculated at photon energies of 1 keV to 100 GeV using XCOM and the obtained results were compared with the measurements at 0.66 and 1.25 MeV. The results showed the possibility of using these waste barite aggregates in the production of heavy concretes. In several cases, some of these properties have been improved. Durability of the concrete made with these waste aggregates was improved. Thus, these materials should be preferably used as aggregates in heavyweight concrete production. (orig.)

  5. Experimental study on durability improvement of fly ash concrete with durability improving admixture.

    Science.gov (United States)

    Quan, Hong-zhu; Kasami, Hideo

    2014-01-01

    In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%-20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized. PMID:25013870

  6. Experimental Study on Durability Improvement of Fly Ash Concrete with Durability Improving Admixture

    Directory of Open Access Journals (Sweden)

    Hong-zhu Quan

    2014-01-01

    Full Text Available In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%–20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized.

  7. Durable fear memories require PSD-95.

    Science.gov (United States)

    Fitzgerald, P J; Pinard, C R; Camp, M C; Feyder, M; Sah, A; Bergstrom, H C; Graybeal, C; Liu, Y; Schlüter, O M; Grant, S G; Singewald, N; Xu, W; Holmes, A

    2015-07-01

    Traumatic fear memories are highly durable but also dynamic, undergoing repeated reactivation and rehearsal over time. Although overly persistent fear memories underlie anxiety disorders, such as posttraumatic stress disorder, the key neural and molecular mechanisms underlying fear memory durability remain unclear. Postsynaptic density 95 (PSD-95) is a synaptic protein regulating glutamate receptor anchoring, synaptic stability and certain types of memory. Using a loss-of-function mutant mouse lacking the guanylate kinase domain of PSD-95 (PSD-95(GK)), we analyzed the contribution of PSD-95 to fear memory formation and retrieval, and sought to identify the neural basis of PSD-95-mediated memory maintenance using ex vivo immediate-early gene mapping, in vivo neuronal recordings and viral-mediated knockdown (KD) approaches. We show that PSD-95 is dispensable for the formation and expression of recent fear memories, but essential for the formation of precise and flexible fear memories and for the maintenance of memories at remote time points. The failure of PSD-95(GK) mice to retrieve remote cued fear memory was associated with hypoactivation of the infralimbic (IL) cortex (but not the anterior cingulate cortex (ACC) or prelimbic cortex), reduced IL single-unit firing and bursting, and attenuated IL gamma and theta oscillations. Adeno-associated virus-mediated PSD-95 KD in the IL, but not the ACC, was sufficient to impair recent fear extinction and remote fear memory, and remodel IL dendritic spines. Collectively, these data identify PSD-95 in the IL as a critical mechanism supporting the durability of fear memories over time. These preclinical findings have implications for developing novel approaches to treating trauma-based anxiety disorders that target the weakening of overly persistent fear memories. PMID:25510511

  8. (Durability of building materials and components)

    Energy Technology Data Exchange (ETDEWEB)

    Naus, D.J.

    1990-11-27

    The traveler participated in the fourth meeting of RILEM 100-TSL, Techniques for Service Life Prediction,'' and The Fifth International Conference on Durability of Building Materials and Components.'' In addition, the traveler met with staff members at Taywood Engineering Ltd., Electricite de France, and AEA Technology. The meeting pertained to performance of concrete materials in nuclear power plant structures, time variation of concrete material properties, methods for evaluating concrete structures, and modeling to predict the effects of degradation factors on concrete materials. As many of the concrete structures in general civil engineering applications as well as nuclear power plant applications in Europe are aging, there is increasing emphasis on assessing the durability of these structures. Information was provided of direct application to the Structural Aging Program which would not have been available without these visits. Of equal, or possibly more importance, was the individual contacts established at the organizations visited. Each organization was extremely interested in both the approach and scope of the Structural Aging Program and requested that they be informed of progress. The initial steps were taken to cooperate with several of these researchers and this should help the Structural Aging Program keep abreast of related European activities. In summary, information obtained during this trip will benefit the ongoing Structural Aging Program by informing Oak Ridge National Laboratory (ORNL) of the extensive European research programs addressing the durability of concrete structures, and also by forming and strengthening acquaintances with counterparts in other countries, thus enhancing the basis for possible international cooperation.

  9. Microcracking and durability of high strength concretes

    International Nuclear Information System (INIS)

    Durability of 28 days compressive strength concrete of 20 to 120 MPa has been studied. The ability of concrete to transport aggressive agents has been determined for four properties: the air permeability, the chloride diffusivity, the water absorption and the carbonation. A chloride migration test for high and very high strength concrete (HSC and VHSC) has been built. The relationship between transport properties and the compressive strength after one and 28 days of humid curing has always the same shape: transport decreases when strength increases. However, transport properties often vary in the ordinary concrete field. Beyond, the domain is much more limited. The relationship between transport properties and strength valid for ordinary concrete can not be simply extrapolated for HSC and VHSC. To determine the part of microcracking of HSC and VHSC, concrete behaviour stored in two mediums has been studied: the ones shaming the storing condition of concrete in auto-desiccation, the others reproducing the storing conditions of concrete in desiccation. Auto-desiccation (measuring relative humidity at balance) and desiccation (measuring mass losses) have been showed. Microcracks and shrinkage strains have been measured. It has been showed that auto-desiccation microcracks proving in HSC or VHSC don't question the durability. Microcracks, as for permeability, do not develop between 28 days and one year. On the contrary, desiccation microcracks observed in HSC and VHSC, increase with transport properties between 28 days and 1.5 year. Thus, a bulk concrete is always more durable than a cover concrete. At last, the good influence of increase of curing of 1 to 28 days on the transport of all concretes has been emphasized. (author)

  10. Pour une agriculture mondiale, productive et durable

    OpenAIRE

    Gautier, Henri

    2015-01-01

    Ancien directeur du département Agriculture et développement durable de la Banque mondiale, Michel Petit nous livre un essai directement inspiré de son expérience au service des agricultures du monde. La critique du productivisme, en particulier de son impact sur les ressources naturelles, peut-elle faire l’impasse sur le rôle déterminant de la productivité agricole dans les processus de développement économique ? Dans la lignée des travaux de Théodore Schultz, prix Nobel d’économie en 1979 p...

  11. Prognosing the durability of polymer sealings

    OpenAIRE

    W. Okularczyk; Kwiatkowski, D.

    2006-01-01

    Purpose: The paper describes the phenomena connected with the sealing for water hydraulic systems.Design/methodology/approach: For the durability tests two types of sealings, made of three polymeric materials recommended for use in water hydraulics systems have been used. In all investigation arrangements the same guide elements have been used. The tests have been performed maintaining water pressure on the sealing at a level of p = 8±1 MPa and the average speed of the piston rod of v ≈ 0.35 ...

  12. Durable, Low-Surface-Energy Treatments

    Science.gov (United States)

    Willis, Paul B.; Mcelroy, Paul M.; Hickey, Gregory S.

    1992-01-01

    Chemical treatment for creation of durable, low-surface-energy coatings for glass, ceramics and other protonated surfaces easily applied, and creates very thin semipermanent film with extremely low surface tension. Exhibits excellent stability; surfaces retreated if coating becomes damaged or eroded. Uses include water-repellent surfaces, oil-repellent surfaces, antimigration barriers, corrosion barriers, mold-release agents, and self-cleaning surfaces. Film resists wetting by water, alcohols, hydrocarbon solvents, and silicone oil. Has moderate resistance to abrasion, such as rubbing with cloths, and compression molding to polymers and composite materials.

  13. Advanced Face Gear Surface Durability Evaluations

    Science.gov (United States)

    Lewicki, David G.; Heath, Gregory F.

    2016-01-01

    The surface durability life of helical face gears and isotropic super-finished (ISF) face gears was investigated. Experimental fatigue tests were performed at the NASA Glenn Research Center. Endurance tests were performed on 10 sets of helical face gears in mesh with tapered involute helical pinions, and 10 sets of ISF-enhanced straight face gears in mesh with tapered involute spur pinions. The results were compared to previous tests on straight face gears. The life of the ISF configuration was slightly less than that of previous tests on straight face gears. The life of the ISF configuration was slightly greater than that of the helical configuration.

  14. The Durability of Epoxy Resin Coating

    Institute of Scientific and Technical Information of China (English)

    ZHAO Fujun; BA Hengjing; GAO Xiaojian

    2008-01-01

    The durability of epoxy resin coating was studied under environments with relative humidity(RH) of 98%-100%, at 55 ℃ for 900 h, at 65℃ for 700 h and at 75 ℃ for 400 h, respectively. Peel strength test, dynamical mechanical thermal analysis (DMTA), infrared spectroscopy (IR) and energy dispersive X-ray spectroscopy (EDX) were employed for measurements. Peel strength indicated the development of adhesive property of the coating, DMTA indicated the development of physical property, IR revealed the development of chemical structure, and EDX showed surface element change of the coating. All these results show a good time-temperature equivalence characteristic between humidity aging time and temperature.

  15. Relationship Between Construction Depreciation, Durability and Fiability

    Directory of Open Access Journals (Sweden)

    Adrian Şerbănoiu

    2006-01-01

    Full Text Available It is estimated that within Europe the value of all structures (infrastructure and built environment represent a value of approximately 50\\% of the national wealth of most countries. Approximately 50\\% of the expenditures in the construction industry are spent on repair, maintenance and remediation of existing structures. In the future these expenses will probably increase even more. A large proportion of these expenses are due to problems related to lacking durability of concrete structures. Thus, to reduce these expenses it is required to make designs for the service life of concrete structures, in which the service life is explicitly specified.

  16. Long Term Durability of Glass Reinforced Composites

    OpenAIRE

    Cain, Jason James

    2008-01-01

    This dissertation discusses topics related to the performance and long-term durability of glass-reinforced composites. The first portion of this dissertation describes work to assess the effect that post-curing has on widely used E-glass/vinyl-ester composites (E-glass/Derakane 510-A and E-glass/Derakane 8084). It is shown that post-curing can have significant positive effects on the initial material properties of glass-reinforced vinyl ester composites. Furthermore, the post-cure of 82Â...

  17. Product Durability, Solid Waste Management and Market Structure

    OpenAIRE

    Runkel, Marco

    1999-01-01

    For a durable consumption good which turns into waste after consumption, the socially optimal durability increases with an increase in the marginal environmental damage. In a laissez-faire equilibrium under perfect competition, producers fail to provide an efficient product design, i.e. durability is inefficiently small, whereas the amount of solid waste is inefficiently large. The market failure is corrected simply by Pigouvian taxation which also can be interpreted as an extension of the pr...

  18. Probabilistic assessment of the durability performance of concrete structures

    OpenAIRE

    Ferreira, Rui Miguel, ed. lit.; Jalali, Said; Gjørv, Odd E.

    2004-01-01

    In recent years, much research work has been carried out in order to obtain a more controlled durability and long-term performance of concrete structures in chloride containing environments. In particular, the development of new procedures for probability-based durability design has proved to be very valuable. In order to provide more data and experience with probability-based durability design, two relatively new concrete structures in Norwegian harbours were selected for detailed investigat...

  19. Intrahousehold Bargaining and the Demand for Consumer Durables in Brazil

    OpenAIRE

    Polato e Fava, Ana Cláudia; Arends-Kuenning, Mary P.

    2013-01-01

    In Brazil, wives do most of the household work. About sixty percent of them also work outside the household, working a total of about 10 hours more per week than men. Because of this unequal distribution of household work, husbands and wives might have different priorities regarding the purchase of durable goods. Although both husbands and wives enjoy entertainment durable goods, wives might have a relative preference for household-production durable goods such as washing machines over entert...

  20. DURABILITY OF ASPHALT CONCRETE MIXTURES USING DOLOMITE AGGREGATES

    Directory of Open Access Journals (Sweden)

    Imad Al-Shalout

    2015-12-01

    Full Text Available This study deals with the durability of asphalt concrete, including the effects of different gradations, compaction temperatures and immersion time on the durability potential of mixtures. The specific objectives of this study are: to investigate the effect of compaction temperature on the mechanical properties of asphalt concrete mixtures; investigate the effect of bitumen content and different aggregate gradations on the durability potential of bituminous mixtures.

  1. Sensitivity study on durability variables of marine concrete structures

    Science.gov (United States)

    Zhou, Xin'gang; Li, Kefei

    2013-06-01

    In order to study the influence of parameters on durability of marine concrete structures, the parameter's sensitivity analysis was studied in this paper. With the Fick's 2nd law of diffusion and the deterministic sensitivity analysis method (DSA), the sensitivity factors of apparent surface chloride content, apparent chloride diffusion coefficient and its time dependent attenuation factor were analyzed. The results of the analysis show that the impact of design variables on concrete durability was different. The values of sensitivity factor of chloride diffusion coefficient and its time dependent attenuation factor were higher than others. Relative less error in chloride diffusion coefficient and its time dependent attenuation coefficient induces a bigger error in concrete durability design and life prediction. According to probability sensitivity analysis (PSA), the influence of mean value and variance of concrete durability design variables on the durability failure probability was studied. The results of the study provide quantitative measures of the importance of concrete durability design and life prediction variables. It was concluded that the chloride diffusion coefficient and its time dependent attenuation factor have more influence on the reliability of marine concrete structural durability. In durability design and life prediction of marine concrete structures, it was very important to reduce the measure and statistic error of durability design variables.

  2. Combined Hydrophobicity and Mechanical Durability through Surface Nanoengineering

    Science.gov (United States)

    Elliott, Paul R.; Stagon, Stephen P.; Huang, Hanchen; Furrer, David U.; Burlatsky, Sergei F.; Filburn, Thomas P.

    2015-04-01

    This paper reports combined hydrophobicity and mechanical durability through the nanoscale engineering of surfaces in the form of nanorod-polymer composites. Specifically, the hydrophobicity derives from nanoscale features of mechanically hard ZnO nanorods and the mechanical durability derives from the composite structure of a hard ZnO nanorod core and soft polymer shell. Experimental characterization correlates the morphology of the nanoengineered surfaces with the combined hydrophobicity and mechanical durability, and reveals the responsible mechanisms. Such surfaces may find use in applications, such as boat hulls, that benefit from hydrophobicity and require mechanical durability.

  3. Study on determination of durability analysis process and fatigue damage parameter for rubber component

    International Nuclear Information System (INIS)

    Rubber components, which have been widely used in the automotive industry as anti-vibration components for many years, are subjected to fluctuating loads, often failing due to the nucleation and growth of defects or cracks. To prevent such failures, it is necessary to understand the fatigue failure mechanism for rubber materials and to evaluate the fatigue life for rubber components. The objective of this study is to develop a durability analysis process for vulcanized rubber components, that can predict fatigue life at the initial product design step. The determination method of nonlinear material constants for FE analysis was proposed. Also, to investigate the applicability of the commonly used damage parameters, fatigue tests and corresponding finite element analyses were carried out and normal and shear strain was proposed as the fatigue damage parameter for rubber components. Fatigue analysis for automotive rubber components was performed and the durability analysis process was reviewed

  4. Durability of thin-walled concrete structures

    International Nuclear Information System (INIS)

    The aim of the present document is to draw up a survey of knowledge of the problems of ageing of reinforced concrete shell structure atmospheric coolers. The exposure conditions are particularly favourable to the induction and development of degradation which, because of the thinness of the reinforced concrete can compromise the stability and the durability of coolers. The study will be axed on the link between the specific characteristics of coolers from the point of view of operation, design and environment, also the durability of reinforced concrete. The set of factors exerting their influence on the reinforced concrete of the shell structure (condensates, rain water, temperature and humidity gradients, dynamic loads, weathering, etc.) is particularly complex. The principal degradation reactions involved are classified according to the chemical and physical action on concrete and on the reinforcement. Particular emphasis is placed on the analysis of degradation processes and the influence of the characteristics of the materials and of the medium. The aim is to determine the mechanisms which present the greatest risk for coolers. The interaction between the degradation to concrete and the change in mechanical characteristics is also studied

  5. CHP Fuel Cell Durability Demonstration - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Petrecky, James; Ashley, Christopher J

    2014-07-21

    Plug Power has managed a demonstration project that has tested multiple units of its high-temperature, PEM fuel cell system in micro-combined heat and power (μ-CHP) applications in California. The specific objective of the demonstration project was to substantiate the durability of GenSys Blue, and, thereby, verify its technology and commercial readiness for the marketplace. In the demonstration project, Plug Power, in partnership with the National Fuel Cell Research Center (NFCRC) at the University of California, Irvine (UCI), and Sempra, will execute two major tasks: • Task 1: Internal durability/reliability fleet testing. Six GenSys Blue units will be built and will undergo an internal test regimen to estimate failure rates. This task was modified to include 3 GenSys Blue units installed in a lab at UCI. • Task 2: External customer testing. Combined heat and power units will be installed and tested in real-world residential and/or light commercial end user locations in California.

  6. Durability of composites in a marine environment

    CERN Document Server

    Rajapakse, Yapa

    2014-01-01

    Composites are widely used in marine applications. There is considerable experience of glass reinforced resins in boats and ships but these are usually not highly loaded. However, for new areas such as offshore and ocean energy there is a need for highly loaded structures to survive harsh conditions for 20 years or more. High performance composites are therefore being proposed. This book provides an overview of the state of the art in predicting the long term durability of composite marine structures. The following points are covered: •       Modelling water diffusion •       Damage induced by water •       Accelerated testing •       Including durability in design •       In-service experience. This is essential reading for all those involved with composites in the marine industry, from initial design and calculation through to manufacture and service exploitation. It also provides information unavailable elsewhere on the mechanisms involved in degradation and how to t...

  7. Experimental Investigation on Contribution of CFRP Attachment to Durability of Reinforced Concrete Structure Subjected to Chloride Attack

    Institute of Scientific and Technical Information of China (English)

    Chen Fengshan; Zhao Guofan; Pan Deqiang

    2006-01-01

    The function of externally-bonded carbon fiber reinforced polymer (CFRP) in preventing chloride from entering into concrete is verified by experiment. The results show that externally-bonded CFRP can be considered as a part of corrosion prevention system of strengthened concrete structures subjected to chloride ingress, and the contribution of CFRP should be considered in evaluation of durability of reinforced concrete structures with externally-bonded CFRP. With the effective shielding function of CFRP considered, an equation for residual lifetime prediction of concrete structures with externally-bonded CFRP is derived from Ficks dispersion law. CFRP has two functions for coastal concrete structures, including strengthening and increasing durability as part of corrosion prevention system.

  8. Evaluation and prediction of reinforced concrete durability by means of durability indicators. Part I : New performance based approach

    OpenAIRE

    BAROGHEL BOUNY, V

    2006-01-01

    This paper presents a new performance-based approach devoted to the evaluation and the prediction of the durability of reinforced concrete RC structures. It is based upon durability indicators DIs and monitoring parameters. This paper is separated in two parts. In this part I first, the selected panel of "universal" DIs is presented. A system of classes with respect to the "potential" durability of RC is then proposed relatively to these DIs. These classes are intended for mixture comparison ...

  9. Preventing stroke

    Science.gov (United States)

    Stroke - prevention; CVA - prevention; cerebral vascular accident - prevention; TIA - prevention, transient ischemic attack - prevention ... live a longer, healthier life. This is called preventive care. An important way to help prevent stroke ...

  10. Preventing medical device recalls

    CERN Document Server

    Raheja, Dev

    2014-01-01

    Introduction to Medical Device RequirementsIntroductionThe ChallengesSources of ErrorsUnderstanding the Science of Safety     Overview of FDA Quality System Regulation     Overview of Risk Management Standard ISO 14971     Overview of FDA Device Approval Process     Overview of Regulatory Requirements for Clinical TrialsSummaryReferencesPreventing Recalls during Specification WritingIntroductionConduct Requirements Analysis to Identify Missing RequirementsSpecifications for Safety, Durability, and

  11. Quality differentiation of durable goods in secondary markets

    Directory of Open Access Journals (Sweden)

    Saito Richard

    2003-01-01

    Full Text Available This paper presents a framework to study how changes in exogenous parameters, such as quality levels of new and used durables, affect the composition of durable good stocks. Our model extends the previous literature by including the endogeneity of prices and qualities. Our results could be applied to evaluate policies for controlling the externality level associated with the use and quality of durable goods in the long-term. We studied the characterization of the demand under a special situation: the consumer can choose the operation and/or maintenance level in the period the durable goods are new, which determines the quality levels for the subsequent periods. Comparative statics is performed to analyze the effects of exogenous variable change on the composition of durable stocks, and thus its impact on the externality level associated with each quality level. Contrary to most expectations, we provide an example in which the regulator imposes stricter quality standards for new durables to decrease negative externality associated with the use of durables. In this example, the comparative static results show that policies focusing only on new durable externality control may turn out to increase total externality, since stocks of older vintages may increase.

  12. Cement replacement materials. Properties, durability, sustainability

    Energy Technology Data Exchange (ETDEWEB)

    Ramezanianpour, Ali Akbar [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Concrete Technology Center

    2014-04-01

    The aim of this book is to present the latest findings in the properties and application of Supplementary Cementing Materials and blended cements currently used in the world in concrete. Sustainability is an important issue all over the world. Carbon dioxide emission has been a serious problem in the world due to the greenhouse effect. Today many countries agreed to reduce the emission of CO2. Many phases of cement and concrete technology can affect sustainability. Cement and concrete industry is responsible for the production of 7% carbon dioxide of the total world CO2 emission. The use of supplementary cementing materials (SCM), design of concrete mixtures with optimum content of cement and enhancement of concrete durability are the main issues towards sustainability in concrete industry.

  13. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1998-01-01

    and the pore structure.Mechanical load is obtained by exposing beams to 4-point bending until a predefined crack width is reached. A test arrangement is developed. The surface crack pattern is characterized using video-scanning and digital image analysis. As environmental load, exposure to 1) a...... concentrated chloride solution or 2) water (capillary suction) is used. Penetration of chlorides will be characterized qualitatively (Color-test) as well as quantitatively (Rapid Chloride Test from Germann).Additional durability tests (freeze-thaw, water vapour diffusion, chloride permeability) and studies of...... pore structure are made on specimens drilled or sawed from beams after unloading (mechanical load). The pore structure of the concretes will be studied by microscopy, sorption and suction curves. The test programme involves three different concrete qualities (water-cement ratios). Both steel fibres (ZP...

  14. Durable and Robust Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Hjalmarsson, Per; Knibbe, Ruth; Hauch, Anne;

    The solid oxide fuel cell (SOFC) is an attractive technology for the generation of electricity with high efficiency and low emissions. Risø DTU (now DTU Energy Conversion) works closely together with Topsoe Fuel Cell A/S in their effort to bring competitive SOFC systems to the market. This 2-year...... project had as one of its’ overarching goals to improve durability and robustness of the Danish solid oxide fuel cells. The project focus was on cells and cell components suitable for SOFC operation in the temperature range 600 – 750 °C. The cells developed and/or studied in this project are intended for....... The fact that degradation and robustness is not very well explored or understood at operating temperatures below 750 °C, provides motivation for focussing on materials and cells suitable for, and operated in this temperature range. A significant part of this project was concerned with improved...

  15. Glass Durability Modeling, Activated Complex Theory (ACT)

    International Nuclear Information System (INIS)

    The most important requirement for high-level waste glass acceptance for disposal in a geological repository is the chemical durability, expressed as a glass dissolution rate. During the early stages of glass dissolution in near static conditions that represent a repository disposal environment, a gel layer resembling a membrane forms on the glass surface through which ions exchange between the glass and the leachant. The hydrated gel layer exhibits acid/base properties which are manifested as the pH dependence of the thickness and nature of the gel layer. The gel layer has been found to age into either clay mineral assemblages or zeolite mineral assemblages. The formation of one phase preferentially over the other has been experimentally related to changes in the pH of the leachant and related to the relative amounts of Al+3 and Fe+3 in a glass. The formation of clay mineral assemblages on the leached glass surface layers ,lower pH and Fe+3 rich glasses, causes the dissolution rate to slow to a long-term steady state rate. The formation of zeolite mineral assemblages ,higher pH and Al+3 rich glasses, on leached glass surface layers causes the dissolution rate to increase and return to the initial high forward rate. The return to the forward dissolution rate is undesirable for long-term performance of glass in a disposal environment. An investigation into the role of glass stoichiometry, in terms of the quasi-crystalline mineral species in a glass, has shown that the chemistry and structure in the parent glass appear to control the activated surface complexes that form in the leached layers, and these mineral complexes ,some Fe+3 rich and some Al+3 rich, play a role in whether or not clays or zeolites are the dominant species formed on the leached glass surface. The chemistry and structure, in terms of Q distributions of the parent glass, are well represented by the atomic ratios of the glass forming components. Thus, glass dissolution modeling using simple atomic

  16. Thermal fatigue durability for advanced propulsion materials

    Science.gov (United States)

    Halford, Gary R.

    1989-01-01

    A review is presented of thermal and thermomechanical fatigue (TMF) crack initiation life prediction and cyclic constitutive modeling efforts sponsored recently by the NASA Lewis Research Center in support of advanced aeronautical propulsion research. A brief description is provided of the more significant material durability models that were created to describe TMF fatigue resistance of both isotropic and anisotropic superalloys, with and without oxidation resistant coatings. The two most significant crack initiation models are the cyclic damage accumulation model and the total strain version of strainrange partitioning. Unified viscoplastic cyclic constitutive models are also described. A troika of industry, university, and government research organizations contributed to the generation of these analytic models. Based upon current capabilities and established requirements, an attempt is made to project which TMF research activities most likely will impact future generation propulsion systems.

  17. Durability of Silicate Glasses: An Historical Approach

    Energy Technology Data Exchange (ETDEWEB)

    Farges, Francois; /Museum Natl. Hist. Natur. /Stanford U., Geo. Environ. Sci.; Etcheverry, Marie-Pierre; /Marne la Vallee U.; Haddi, Amine; /Marne la Valle U.; Trocellier,; /Saclay; Curti, Enzo; /PSI, Villigen; Brown, Gordon E., Jr.; /SLAC, SSRL

    2007-01-02

    We present a short review of current theories of glass weathering, including glass dissolution, and hydrolysis of nuclear waste glasses, and leaching of historical glasses from an XAFS perspective. The results of various laboratory leaching experiments at different timescales (30 days to 12 years) are compared with results for historical glasses that were weathered by atmospheric gases and soil waters over 500 to 3000 years. Good agreement is found between laboratory experiments and slowly leached historical glasses, with a strong enrichment of metals at the water/gel interface. Depending on the nature of the transition elements originally dissolved in the melt, increasing elemental distributions are expected to increase with time for a given glass durability context.

  18. Durable fiber reinforced self-compacting concrete

    International Nuclear Information System (INIS)

    In order to produce thin precast elements, a self-compacting concrete was prepared. When manufacturing these elements, homogenously dispersed steel fibers instead of ordinary steel-reinforcing mesh were added to the concrete mixture at a dosage of 10% by mass of cement. An adequate concrete strength class was achieved with a water to cement ratio of 0.40. Compression and flexure tests were carried out to assess the safety of these thin concrete elements. Moreover, serviceability aspects were taken into consideration. Firstly, drying shrinkage tests were carried out in order to evaluate the contribution of steel fibers in counteracting the high concrete strains due to a low aggregate-cement ratio. Secondly, the resistance to freezing and thawing cycles was investigated on concrete specimens in some cases superficially treated with a hydrophobic agent. Lastly, both carbonation and chloride penetration tests were carried out to assess durability behavior of this concrete mixture

  19. Lightweight, durable lead-acid batteries

    Science.gov (United States)

    Lara-Curzio, Edgar; An, Ke; Kiggans, Jr., James O; Dudney, Nancy J; Contescu, Cristian I; Baker, Frederick S; Armstrong, Beth L

    2013-05-21

    A lightweight, durable lead-acid battery is disclosed. Alternative electrode materials and configurations are used to reduce weight, to increase material utilization and to extend service life. The electrode can include a current collector having a buffer layer in contact with the current collector and an electrochemically active material in contact with the buffer layer. In one form, the buffer layer includes a carbide, and the current collector includes carbon fibers having the buffer layer. The buffer layer can include a carbide and/or a noble metal selected from of gold, silver, tantalum, platinum, palladium and rhodium. When the electrode is to be used in a lead-acid battery, the electrochemically active material is selected from metallic lead (for a negative electrode) or lead peroxide (for a positive electrode).

  20. Durable rough skin phantoms for optical modeling

    International Nuclear Information System (INIS)

    Skin phantoms are often used to study and model light propagation. However, existing skin phantoms overlook the important effect of surface roughness on light propagation patterns. This paper reports the construction of durable phantoms with controllable surface roughness and bulk optical properties. With silica microspheres as the scattering particles, we theoretically model the scatterer density required to achieve the desired phantom optical properties before fabrication. The surface roughness and the attenuation coefficients of the constructed phantoms were validated using optical profilometry and ballistic spatial filter photometry. These rough skin phantoms were originally developed for laser speckle studies, but could also be used for studying optical phenomena where light experiences surface and bulk scattering at the same time. (paper)

  1. Durability of waste glass flax fiber reinforced mortar

    International Nuclear Information System (INIS)

    The main concern for natural fibre reinforced mortar composites is the durability of the fibres in the alkaline environment of cement. The composites may undergo a reduction in strength as a result of weakening of the fibres by a combination of alkali attack and fibre mineralisation. In order to enhance the durability of natural fiber reinforced cement composites several approaches have been studied including fiber impregnation, sealing of the matrix pore system and reduction of matrix alkalinity through the use of pozzolanic materials. In this study waste glass powder was used as a pozzolanic additive to improve the durability performance of flax fiber reinforced mortar (FFRM). The durability of the FFRM was studied by determining the effects of ageing in water and exposure to wetting and drying cycles; on the microstructures and flexural behaviour of the composites. The mortar tests demonstrated that the waste glass powder has significant effect on improving the durability of FFRM.

  2. Durability of Prunus africana: Evidence of Biocidal and Lipophilic Properties Responsible for Natural Durability

    International Nuclear Information System (INIS)

    Analysis of the prunus africana sapwood and heartwood extracts was studied with the aim of understanding the reasons for it's natural durability. Soxhlet extraction of wood powder using different solvents was done. The extracts were tested against the fungi coriolus versicolor, Poria placenta and Aureobasidium pullulans at concentrations of 50, 100, 500 and 1000 ppm. Soxhlet extraction of wood blocks using the same solvents was also carried out and the wood blocks finally tested against fungi and termites. The results showed high exhibition rate against fungi at low extract concentrations. Extracted wood blocks showed low resistance against termites while the un-extracted ones were resistant. Analysis of the products present in hexane, dichloromethane, acetone, toluene/ethanol and water extracts by HPLC indicates presence of phenols and lipophilic compounds, which could be associated with the preceding results. Inhibition against fungi increased with extract concentration and decreased with time. In some instances at high concentration, fungal growth started after the control Petri-dish was fully colonized. Inspite of the fungal and termiticidal properties of certain products contained in the extracts, these properties do not entirely explain the reasons for the high durability. Chemical synthesis with formulations based on the natural components present in the extracts of such durable wood could be interesting as potential additives in fungicides and insecticides. Such formulations based on natural compounds could environmentally friendly

  3. Encapsulation of TRISO particle fuel in durable soda-lime-silicate glasses

    International Nuclear Information System (INIS)

    Tri-Structural Isotropic (TRISO) coated particle-fuel is a key component in designs for future high temperature nuclear reactors. This study investigated the suitability of three soda lime silicate glass compositions, for the encapsulation of simulant TRISO particle fuel. A cold press and sinter (CPS) methodology was employed to produce TRISO particle–glass composites. Composites produced were determined to have an aqueous durability, fracture toughness and Vickers’ hardness comparable to glasses currently employed for the disposal of high level nuclear wastes. Sintering at 700 °C for 30 min was found to remove all interconnected porosity from the composite bodies and oxidation of the outer pyrolytic carbon layer during sintering was prevented by processing under a 5% H2/N2 atmosphere. However, the outer pyrolytic carbon layer was not effectively wetted by the encapsulating glass matrix. The aqueous durability of the TRISO particle–glass composites was investigated using PCT and MCC-1 tests combined with geochemical modelling. It was found that durability was dependent on silicate and calcium solution saturation. This study provides significant advancements in the preparation of TRISO particle encapsulant waste forms. The potential for the use of non-borosilicate sintered glass composites for TRISO particle encapsulation has been confirmed, although further refinements are required

  4. Covercrete with hybrid functions - A novel approach to durable reinforced concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Tang, L.; Zhang, E.Q. [Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Fu, Y. [KTH Royal Institute of Technology, SE-106 91 Stockholm (Sweden); Schouenborg, B.; Lindqvist, J.E. [CBI Swedish Cement and Concrete Research Institute, c/o SP, Box 857, SE-501 15 Boraas (Sweden)

    2012-12-15

    Due to the corrosion of steel in reinforced concrete structures, the concrete with low water-cement ratio (w/c), high cement content, and large cover thickness is conventionally used for prolonging the passivation period of steel. Obviously, this conventional approach to durable concrete structures is at the sacrifice of more CO{sub 2} emission and natural resources through consuming higher amount of cement and more constituent materials, which is against sustainability. By placing an economically affordable conductive mesh made of carbon fiber or conductive polymer fiber in the near surface zone of concrete acting as anode we can build up a cathodic prevention system with intermittent low current density supplied by, e.g., the solar cells. In such a way, the aggressive negative ions such as Cl{sup -}, CO{sub 3}{sup 2-}, and SO{sub 4}{sup 2-} can be stopped near the cathodic (steel) zone. Thus the reinforcement steel is prevented from corrosion even in the concrete with relatively high w/c and small cover thickness. This conductive mesh functions not only as electrode, but also as surface reinforcement to prevent concrete surface from cracking. Therefore, this new type of covercrete has hybrid functions. This paper presents the theoretical analysis of feasibility of this approach and discusses the potential durability problems and possible solutions to the potential problems. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Durability of the anti-erosive effect of surfaces sealants under erosive abrasive conditions

    OpenAIRE

    Wegehaupt, Florian J; Tauböck, Tobias T.; Attin, Thomas

    2013-01-01

    OBJECTIVE: To test the durability of sealants applied for prevention of erosive dentine mineral loss under erosive/abrasive conditions. METHODS: Forty-eight bovine dentine samples doped with (32)P were randomly allocated to four groups (1-4). All samples performed a de- and remineralizations pre-cycling (6 × 1 min erosion in HCl: pH 3.0, mean time and overnight immersion in artificial saliva) for 1 day. Sealing was done as follows; (1) unsealed, (2) Seal & Protect, (3) K-0184 (experimental...

  6. Information report realized for the Senate delegation to the territory management and sustainable development on the local energies; Rapport d'information fait au nom de la delegation du Senat a l'amenagement et au developpement durable du territoire sur les energies locales

    Energy Technology Data Exchange (ETDEWEB)

    Belot, C.; Juilhard, J.M

    2006-06-15

    This report deals with the renewable energies and the local development called the territory intelligence in action. Taking into account the place of the electricity in the french energy accounting and the part of the nuclear in its production, the local authorities have to act in the heat domain, which is the first energy need in France, far in front of the specific electricity (those which cannot be replace by other type of energy). But 80% of the heat is today covered by fossil energies. No actions to change this situation will be done without a real implication of the local government. The authors preconize an ambitious objective: cover 50% of the heat needs from renewable energies in the next generat This objective must rely on a program called ''alternative energies''. In this framework the authors provide recommendations on the implementation of the renewable energies as an essential challenge for the local authorities. (A.L.B.)

  7. Opinion presented on behalf of the Economical Affairs Commission on the finance bill for 2010 (n. 1946) - Volume II: Sustainable ecology, development and planning. Industry and energy; Avis presente au nom de la Commission des Affaires Economiques sur le projet de loi de finances pour 2010 (n.1946), tome 2 ecologie, developpement et amenagement durables industrie et energie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-10-15

    This report of the French National Assembly first presents the different programmes and actions related to energy and industry for which credits are foreseen in the French finance bill for 2010: development of firms and employment, energy policy, after-mining policy, struggle against climate change, management of ecology, energy, sustainable development, and sea policies, research in the field of energy and sustainable development and planning. The author then outlines the importance of the creation of conditions for a green growth in order to cope with an unprecedented crisis which ruins industrial employment. This implies the support of strategic sectors (energy-efficient building, evolution towards green chemistry, photovoltaic solar energy, renewable heat, innovating vehicles), the implementation of new priorities (smart grids, management of raw materials), and the emergence of ecological technologies promoted by the new tools of a climate policy (carbon tax introduction, improvement of carbon markets). It also implies an industrial output for research by means of a networking of actors (development of competitiveness poles, participation to European partnerships), and a reinforcement of the industrial horizon in the research policy (patenting, start-up development, support to innovating small and middle-sized companies, implementation of a true French capital-risk sector)

  8. Opinion presented on behalf of the Foreign Affairs Commission on the Finance bill for 2011 (n. 2824), volume 5 Ecology, Sustainable Development and Land Planning; Avis presente au nom de la Commission des Affaires Etrangeres sur le projet de loi de finances pour 2011 (n. 2824), tome 5 ecologie, developpement et amenagement durables

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    This report first gives an overview of the action of the French diplomacy for the protection of the environment. It comments the participation to international and European negotiations, evokes the negotiations within the Union for the Mediterranean, and outlines the quality of the French administrative arrangement (relationship between the Ministry of Foreign Affairs and the Ministry of Ecology, increasing importance of a network of correspondents, support to NGOs, and role of the ADEME). Then, the author reports the ongoing works of the European Union on energy and climate (carbon tax, carbon emission reductions, cooperation with Russia, challenges of energy efficiency improvement in Russia) and comments what comes next the Copenhagen Conference. In the last part, the author highlights the forthcoming challenges which may lead either to success or failure: the Nagoya Conference and the issue of biodiversity management in high seas

  9. Opinion presented on behalf of the Economic Affairs Commission on the Finance bill for 2011 (n. 2824), volume 2 Ecology, Sustainable Development and Land Planning, industry and energy; Avis presente au nom de la Commission des Affaires Economiques sur le projet de loi de finances pour 2011 (n. 2824), tome 2 ecologie, developpement et amenagement durables industrie et energie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    In her introduction, the author gives a description of the difficult context and situation faced by the industrial sector in France, notably because of the growing activity of emerging countries like China, India or Brazil, but also because of the weakness of research industrial valorization and of the innovation policy (losing the manufacturing capacity leads to losing the capacity for innovation). Then, after a critic of the current policy (reform of the professional tax, a boosting plan with limited results), she comments the contents of public programmes concerning firm and job development, energy, the steering of ecology, energy, sustainable development and sea policies, research in energy and sustainable development and land planning. She comments ways and tools aimed at supporting industrial jobs through innovation: the FSI (strategic investment fund), the competitiveness poles, specific aids to small and medium sized enterprises, tax credit related to research activities. She addresses the energy sector, questioning the French supremacy in the nuclear energy and the increase of electricity price, and criticizing the management of the development of renewable energies (high expenses for no industrial development)

  10. Information report, on behalf of the delegation to the national and sustainable development, about the management of household wastes in the French territory; Rapport d'information, au nom de la delegation a l'amenagement et au developpement durable du territoire, sur la gestion des dechets menagers sur le territoire

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-11-01

    The French law from July 13, 1992, relative to the elimination of wastes and to the waste management facilities, was based on four goals: reduction of waste production at the source, transport, valorization by recycling or energy recovery, and disposal of ultimate wastes only. This report makes a status of the situation of wastes management in France, ten years after the enforcement of the 1992 law: persistence of the society problem of wastes, mitigated results (collection, processing, delays, insufficient valorization), present day and future national development stakes (saturated storage and processing facilities, public psychological reserve, environmental conflicts), financing, new proposals (restoring public confidence, transforming harmful effects into richnesses thanks to financial incentives). Some additional information is given in appendixes which make the second part of this report (origin and processing of household wastes, storage facilities with a capacity greater than 20000 t/year, list of incineration facilities in operation, transport of municipal wastes). (J.S.)

  11. Hydraulic Fracture Test to Determine Aggregate Freeze-Thaw Durability

    OpenAIRE

    Desta, Belayneh; Whiting, Nancy M; Snyder, Mark B

    2014-01-01

    The freeze-thaw durability of carbonate aggregates can vary greatly from durable to highly susceptible to freeze-thaw distress. Using nondurable aggregate in concrete pavement exposed to freeze-thaw cycles may lead to serious distress and greatly decrease the pavement’s service life. The testing needed to identify freeze-thaw durable aggregates can take several months to complete. The main objective of this study was to develop a reliable, quick test method for determining the freeze-thaw res...

  12. Testing the durability of concrete with neutron radiography

    International Nuclear Information System (INIS)

    The ability of concrete to withstand the penetration of liquid and oxygen can be described as the durability of concrete. The durability of concrete, can in turn, be quantified by certain characteristics of the concrete such as the porosity, sorptivity and permeability. The quantification of neutron radiography images of concrete structures and, therefore, the determination of concrete characteristics validate conventional measurements. This study compares the neutron radiography capability to obtain quantitative data for porosity and sorptivity in concrete to laboratory or conventional measurements. The effects that water to cement ratio and curing time have on the durability of concrete are investigated

  13. Influence of chloride admixtures on cement matrix durability

    International Nuclear Information System (INIS)

    The influence of various inorganic salts, as chloride admixtures to Portland cement, on the mechanical properties and the durability of the matrix has been studied. The salts used in this study are chromium, nickel and cadmium chlorides. Improved compressive strength values are obtained which have been correlated to the stable metal hydroxide formation in high pH environment. Under static water conditions at 500C, hydrolyzed chloride ions exhibit adverse effects on the matrix durability through rapid release of calcium as calcium chloride in the initial period of leaching. On the contrary, enhanced matrix durability is obtained on long term leaching in the case of cement containing chromium chloride

  14. High gain durable anti-reflective coating

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze' ev R.

    2016-07-26

    Disclosed herein are polysilsesquioxane-based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In one embodiment, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, thermal radical initiator, photo radical initiators, crosslinkers, Si--OH condensation catalyst and nano-fillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

  15. Optical enhancing durable anti-reflective coating

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Sina; Varadarajan, Aravamuthan; Movassat, Meisam

    2016-07-05

    Disclosed herein are polysilsesquioxane based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In embodiments, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in the polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, Si--OH condensation catalyst and/or nanofillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes including flow coating and roll coating, and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

  16. Surface chemistry and durability of borosilicate glass

    International Nuclear Information System (INIS)

    Important glass-water interactions are poorly understood for borosilicate glass radioactive waste forms. Preliminary results show that glass durability is dependent on reactions occurring at the glass-solution interface. CSG glass (18.2 wt. % Na2O, 5.97 wt. % CaO, 11.68 wt. % Al2O3, 8.43 wt. % B2O3, and 55.73 wt. % SiO2) dissolution and net surface H+ and OH- adsorption are minimal at near neutral pH. In the acid and alkaline pH regions, CSG glass dissolution rates are proportional to [H+]adsorbed2 and [OH-]adsorbed0.8, respectively. In contrast, silica gel dissolution and net H+ and OH- adsorption are minimal and independent of pH in acid to neutral solutions. In the alkaline pH region, silica gel dissolution is proportional to [OH-]adsorbed0.9adsorbed. Although Na adsorption is significant for CSG glass and silica gel in the alkaline pH regions, it is not clear if it enhances dissolution, or is an artifact of depolymerization of the framework bonds

  17. Durability of Alkali Activated Blast Furnace Slag

    Science.gov (United States)

    Ellis, K.; Alharbi, N.; Matheu, P. S.; Varela, B.; Hailstone, R.

    2015-11-01

    The alkali activation of blast furnace slag has the potential to reduce the environmental impact of cementitious materials and to be applied in geographic zones where weather is a factor that negatively affects performance of materials based on Ordinary Portland Cement. The scientific literature provides many examples of alkali activated slag with high compressive strengths; however research into the durability and resistance to aggressive environments is still necessary for applications in harsh weather conditions. In this study two design mixes of blast furnace slag with mine tailings were activated with a potassium based solution. The design mixes were characterized by scanning electron microscopy, BET analysis and compressive strength testing. Freeze-thaw testing up to 100 freeze-thaw cycles was performed in 10% road salt solution. Our findings included compressive strength of up to 100 MPa after 28 days of curing and 120 MPa after freeze-thaw testing. The relationship between pore size, compressive strength, and compressive strength after freeze-thaw was explored.

  18. Teeth: Among Nature's Most Durable Biocomposites

    Science.gov (United States)

    Lawn, Brian R.; Lee, James J.-W.; Chai, Herzl

    2010-08-01

    This paper addresses the durability of natural teeth from a materials perspective. Teeth are depicted as smart biocomposites, highly resistant to cumulative deformation and fracture. Favorable morphological features of teeth at both macroscopic and microscopic levels contribute to an innate damage tolerance. Damage modes are activated readily within the brittle enamel coat but are contained from spreading catastrophically into the vulnerable tooth interior in sustained occlusal loading. Although tooth enamel contains a multitude of microstructural defects that can act as sources of fracture, substantial overloads are required to drive any developing cracks to ultimate failure—nature's strategy is to contain damage rather than avoid it. Tests on model glass-shell systems simulating the basic elements of the tooth enamel/dentin layer structure help to identify important damage modes. Fracture and deformation mechanics provide a basis for analyzing critical conditions for each mode, in terms of characteristic tooth dimensions and materials properties. Comparative tests on extracted human and animal teeth confirm the validity of the model test approach and point to new research directions. Implications in biomechanics, especially as they relate to dentistry and anthropology, are outlined.

  19. Durability of tannin-boron-treated timber

    Directory of Open Access Journals (Sweden)

    Gianluca Tondi

    2012-11-01

    Full Text Available Tannin-boron wood preservatives were investigated for their resistance against outdoor agents. This work focused on the analysis of the causes that affect the durability of the tannin-hexamine-treated samples. In particular, dimensional stability, resistance to leaching, and resistance to biological agents were investigated. The combined effect of deterioration agents was evaluated by subjecting the treated samples to simulated and natural weathering tests. The study of the appearance and of the color components (L*, a*, and b* according to CIELAB space of the exposed samples was monitored to assess the efficacy of the tannin-boron formulations for outdoor applications. Significant resistance against the action of water (EN 84, ENV 1250-2 and insects (EN 47 has been demonstrated in specific tests. Conversely, the continuous stress due to artificial and natural weathering deteriorates the color and the visible features of the treated specimens. The combined effect of moisture modifications, solar exposition, and leaching cycles damages the structure of the tannin-based polymeric network and subsequently it negatively affects its preservation properties.

  20. Preventing stroke

    Science.gov (United States)

    Stroke - prevention; CVA - prevention; cerebral vascular accident - prevention; TIA - prevention, transient ischemic attack - prevention ... A stroke occurs when the blood supply is cut off to any part of the brain. A stroke is ...

  1. INFLUENCE OF TEMPERATURE, HUMIDITY AND ULTRAVIOLET IRRADIATION ON DURABILITY AND DURABILITY OF MODIFIED WOOD

    Directory of Open Access Journals (Sweden)

    V. P. Yartsev

    2011-02-01

    Full Text Available Problem statement. A technological mode of wood modification with the use of various sub-stances (kerosene, paraffin, Emukril M, emulsion 252 is described. The influence of type of mod-ifier on mechanical and hydrophysical properties of wood is discussed.Results and conclusions. The effect of elevated temperature on expansion and compression of modified wood is investigated, and the values of coefficients of linear thermal expansion are de-termined. The analysis of the results of the influence of climatic factors (water and UV radiation, repeated freezing/thawing on properties of modified wood is performed. The durability of mod-ified wood is studied.

  2. The hydrogen: a clean and durable energy; L'hydrogene: une energie propre et durable

    Energy Technology Data Exchange (ETDEWEB)

    Alleau, Th. [Association Francaise de l' Hydrogene (France); Nejat Veziroglu, T. [Clean Energy Research Institute, University of Miami (United States); Lequeux, G. [Commission europeenne, DG de la Recherche, Bruxelles (Belgium)

    2000-07-01

    All the scientific experts agree, the hydrogen will be the energy vector of the future. During this conference day on the hydrogen, the authors recalled the actual economic context of the energy policy with the importance of the environmental policy and the decrease of the fossil fuels. The research programs and the attitudes of the France and the other countries facing the hydrogen are also discussed, showing the great interest for this clean and durable energy. They underline the importance of an appropriate government policy, necessary to develop the technology of the hydrogen production, storage and use. (A.L.B.)

  3. Biological durability of wood modified by citric acid

    Directory of Open Access Journals (Sweden)

    Bogoslav Šefc

    2008-07-01

    Full Text Available This paper presents the results of measurement of durability of beech wood (Fagus sylvatica modified by Citric Acid (CA against brown rot fungus Poria placenta according to EN 113. Modification was performedby impregnation with 7.0% CA and 6.5% sodium-hypophosphite (SHP water solution and 10-hour curing at 140 °C. The influence of thermal treatment on durability was also researched. Weight percentage gain (WPG caused by modification, moisture content (MC and mass loss of wood (dm after fungal nutrition were measured. WPG of modified beech wood was 6.1% and that of thermally treated wood was -0.3%. The results showed increased durability of modified wood to be 8.3 times greater than nonmodified, while thermal treatment did not give significant durability improvement. These results indicate modification by CA as a promising alternative, but further research on optimisation of modification parameters is needed to achieve improvement of wood properties.

  4. Thermodynamic model of natural, medieval and nuclear waste glass durability

    International Nuclear Information System (INIS)

    A thermodynamic model of glass durability based on hydration of structural units has been applied to natural glass, medieval window glasses, and glasses containing nuclear waste. The relative durability predicted from the calculated thermodynamics correlates directly with the experimentally observed release of structural silicon in the leaching solution in short-term laboratory tests. By choosing natural glasses and ancient glasses whose long-term performance is known, and which bracket the durability of waste glasses, the long-term stability of nuclear waste glasses can be interpolated among these materials. The current Savannah River defense waste glass formulation is as durable as natural basalt from the Hanford Reservation (106 years old). The thermodynamic hydration energy is shown to be related to the bond energetics of the glass. 69 references, 2 figures, 1 table

  5. High-durability phase-shift film with variable transmittance

    Science.gov (United States)

    Nozawa, Osamu; Shishido, Hiroaki; Kajiwara, Takenori

    2015-10-01

    In order to maintain the lithographic margin and to have sufficient image resolution, attenuated phase shift masks are widely used as a resolution enhancement technique. To improve the radiation durability of the phase shift film, we have developed low oxidation MoSi shifters, such as A6L2, as one option for improving radiation durability. But to provide the best radiation durability, we have developed a new approach eliminating the molybdenum from the phase shift film and introduced a Silicon-Nitride (Si-N) based attenuated phase shift film. Traditionally the transmittance of the phase shift layer is usually around 6%. In the case of a pure Si3N4 film, the transmittance with 180 degree phase shift is around 18%. But, by controlling film structure with a combination of Si-N the transmittance can be tuned to the customers desired transmission value for high durability Mo free attenuated phase shift films.

  6. 40 CFR 86.1820-01 - Durability group determination.

    Science.gov (United States)

    2010-07-01

    ...-Duty Trucks, and Complete Otto-Cycle Heavy-Duty Vehicles § 86.1820-01 Durability group determination...) Combustion cycle (e.g., two stroke, four stroke, Otto cycle, diesel cycle). (2) Engine type (e.g.,...

  7. Opinion on the behalf of the Sustainable Development and Land Planning Commission on the Finance bill for 2011 (n. 2824), volume 7: research and university education, research in the fields of sustainable development; Avis presente Au nom de la Commission du Developpement Durable et de L'amenagement du Territoire sur le projet de loi de finances pour 2011 (n. 2824), tome 7 recherche et enseignement superieur recherche dans les domaines du developpement durable

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    While presenting two programmes which respectively concern the management of surroundings and resources, and the fields of energy and of sustainable development and land planning, and commenting their financial means, their objectives and performance indicators, this report shows that these programmes are facing insufficient grants. Then, it shows that the different public operators (research laboratories, centres and institutions, public agencies) are weakened by decreasing allocations. Three examples are then studied to show the difficulties of these institutions which have to perform fundamental missions with limited means: IFREMER (in the case of oyster control), INRA (for the development of the biotechnology sector) and IRSN (for the safety of nuclear waste storage)

  8. Government Incentives when Pollution Permits are Durable Goods

    OpenAIRE

    Haucap, Justus; Kirstein, Roland

    2001-01-01

    This paper analyzes the incentive effects of pollution taxes versus pollution permits for a revenue maximizing Government that also pursues environmental objectives. In our model, pollution permits are analyzed as durable goods, and the leasing of pollution permits is seen as an equivalent to a pollution tax. We show that environmental policy based on durable pollution permits can be welfare superior to a pollution tax regime. The intuition is that a monopolistic Government would, in order to...

  9. The Dynamic Pricing of Next Generation Consumer Durables

    OpenAIRE

    Barry L. Bayus

    1992-01-01

    Learning curve effects, aspects of consumer demand models (e.g., reservation price distributions, intertemporal utility maximizing behavior), and competitive activity are reasons which have been offered to explain why prices of new durables decline over time. This paper presents an alternative rationale based on the buying behavior for products with overlapping replacement cycles (i.e., next generation products). A model for consumer sales of a new durable is developed by incorporating the re...

  10. Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

    OpenAIRE

    Ganesan Lavanya; Josephraj Jegan

    2015-01-01

    This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study...

  11. Software for probabilistic-based durability analysis of concrete structures

    OpenAIRE

    Ferreira, Rui Miguel, ed. lit.; Jalali, Said

    2005-01-01

    In recent yeras, much reserach works has been carried out in order to obtain a more controlled durability and long-term performance in concrete structures in chloride containing environments. In particular, the developemnt of new procedures for probability-based durability design has been shown to provide a more realistic basis for the an analysis. Although relevant data is still lacking, this approach has been successfully applied to several new concrete structures, where requirements for a ...

  12. Software for probability-based durability analysis of concrete structures

    OpenAIRE

    Ferreira, Rui Miguel, ed. lit.; Jalali, Said

    2005-01-01

    In recent years, much research work has been carried out in order to obtain a more controlled durability and long-term performance of concrete structures in chloride containing environments. In particular, the development of new procedures for probability-based durability design has been shown to provide a more realistic basis for the analysis. Although relevant data is still lacking, this approach has been successfully applied to several new concrete structures, where requirements for ...

  13. Evolutionary Model of a Anonymous Consumer Durable Market

    OpenAIRE

    Joachim Kaldasch

    2013-01-01

    An analytic model is presented that considers the evolution of a market of durable goods. The model suggests that after introduction goods spread always according to a Bass diffusion. However, this phase will be followed by a diffusion process for durable consumer goods governed by a variation-selection-reproduction mechanism and the growth dynamics can be described by a replicator equation. Describing the aggregate sales as the sum of first, multiple and replacement purchase the product life...

  14. Forecasting of durability of waterborne coatings in the machine industry

    OpenAIRE

    K. Lenik; K. Gauda; Z. Lenik

    2009-01-01

    Purpose: The paper presents the problems of forecasting of durability of waterborne acrylic coatings and epoxy coatings designed to protect devices and machine elements.Design/methodology/approach: The durability forecast has been performed on the basis of analyses of time series with the use of trend function extrapolation. Mechanical properties such as: scratch resistance, impact strength, grindability and luster have also been evaluated. Moreover, besides standardized methods, some complem...

  15. Durability of compressed soil-cement bricks

    Directory of Open Access Journals (Sweden)

    Acosta Valle, A.

    2001-06-01

    Full Text Available This papers shows the evaluation process of the durability of compressed soil-cement bricks. A great number of tests were made to determine the behavior of bricks when they are compression loaded and under the influence of moisture. Two different types of soils were used to produce the bricks, a lime-clay soil and a sand one. The sand soil is very resistant. The other one has a limited use. An experimental design was used to test the bricks. It is a rotational and quadratic method with a hexagonal figure which contains replicas at the central point. This method ensures the reliability of test results. Otherwise, it would reduce the amount of specimens necessary for the tests. The optimun moisture content is obtained by using a press machine. It is more rational than the standard Proctor compactation test, because it applies the same type and amount of energy used to produce the bricks. The obtained results show the behavior differences between the two compressed soil-cement bricks subjected to the compression test, water absorption and wetting and drying tests. The durability tests results are very important in the possible use of the bricks produced.

    En el trabajo se evalúa la durabilidad de elementos aglomerados de suelo estabilizado. Se realiza un amplio número de ensayos encaminados a determinar el comportamiento frente a la acción de las cargas y la humedad de dos suelos con características diferentes: uno limo-arcilloso y el otro arenoso. Este último presenta resultados muy favorables en ambas direcciones. El otro, con un posible uso más limitado. Se emplea un método de diseño experimental del tipo rotacional cuadrático en hexágono, con réplicas en el punto central, el que garantiza la confiabilidad de los resultados de los ensayos, a la vez que disminuye la cantidad de especímenes a ensayar. Se determina la humedad óptima a utilizar en las diferentes dosificaciones empleando la máquina compactadora, que resulta m

  16. Assessment of cement durability in repository environment

    International Nuclear Information System (INIS)

    The present research aimed at investigating the durability of cement paste under nuclear waste repository conditions using accelerated tests. Cement paste samples are examined after being exposed to the environmental conditions that are expected to prevail in the repository environment and the results are compared with those obtained with unexposed specimens or specimens exposed to reference conditions. The following exposure conditions were selected: a) Immersion in salt solution, distilled water, or kept in dry storage; b) Room temperature (20 C. degrees) or high temperature (60 C. degrees); c) Immersion time of 30 days or 60 days (not for dry storage); d) Irradiation to a dose of (400 kGy) or background radiation (0 kGy). After exposure to the stressing conditions, the effects of each factor on the cement paste samples were observed by changes in their characteristics. Compressive strength tests were performed on all samples and some of them were investigated in terms of changes in mineralogy by X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA). With the results obtained so far it was possible to point out the following conclusions. First, after a period of immersion in water, cement paste samples further hydrated and presented higher mechanical resistance, as expected. Secondly, dry storage did not allow a complete hydration as a consequence of pore water evaporation. High temperatures intensified this process and led to the ettringite decomposition to meta-ettringite. Thirdly, higher temperature accelerated hydration kinetics and promoted higher mechanical resistance in samples kept under immersion. Fourthly, the irradiation dose applied was unable to change the mineralogy of cement paste samples and fifthly, no statistically significant differences were observed between 30 or 60 days exposure time, for the test conditions

  17. Erectile Function Durability Following Permanent Prostate Brachytherapy

    International Nuclear Information System (INIS)

    Purpose: To evaluate long-term changes in erectile function following prostate brachytherapy. Methods and Materials: This study included 226 patients with prostate cancer and preimplant erectile function assessed by the International Index of Erectile Function-6 (IIEF-6) who underwent brachytherapy in two prospective randomized trials between February 2001 and January 2003. Median follow-up was 6.4 years. Pre- and postbrachytherapy potency was defined as IIEF-6 ≥ 13 without pharmacologic or mechanical support. The relationship among clinical, treatment, and dosimetric parameters and erectile function was examined. Results: The 7-year actuarial rate of potency preservation was 55.6% with median postimplant IIEF of 22 in potent patients. Potent patients were statistically younger (p = 0.014), had a higher preimplant IIEF (p < 0.001), were less likely to be diabetic (p = 0.002), and were more likely to report nocturnal erections (p = 0.008). Potency preservation in men with baseline IIEF scores of 29-30, 24-28, 18-23, and 13-17 were 75.5% vs. 73.6%, 51.7% vs. 44.8%, 48.0% vs. 40.0%, and 23.5% vs. 23.5% in 2004 vs. 2008. In multivariate Cox regression analysis, preimplant IIEF, hypertension, diabetes, prostate size, and brachytherapy dose to proximal penis strongly predicted for potency preservation. Impact of proximal penile dose was most pronounced for men with IIEF of 18-23 and aged 60-69. A significant minority of men who developed postimplant impotence ultimately regained erectile function. Conclusion: Potency preservation and median IIEF scores following brachytherapy are durable. Thoughtful dose sparing of proximal penile structures and early penile rehabilitation may further improve these results.

  18. Evaluation and prediction of reinforced concrete durability by means of durability indicators. Part II : Multi-level predictive modelling

    OpenAIRE

    BAROGHEL BOUNY, V; Nguyen, TQ; Thiery, M.; DANGLA, P; Belin, P

    2006-01-01

    This paper presents a new performance-based approach devoted to the evaluation and the predition of the durability of reinforced concrete structures. It is based upon durability indicators DIs and monitoring parameters. This paper is separated in two parts. In Part I, the selected panel of "universal" DIs, along with performance-based specifications with regards to protection against reinforcement corrosion, have been presented. In this Part II, within the framework of the prediction of the s...

  19. Durability of reinforced concrete exposed to aggressive conditions

    Directory of Open Access Journals (Sweden)

    Aguirre, A. M.

    2013-03-01

    Full Text Available Reinforced concrete is the most widely used construction material in the world. The combination of high compressive strength, afforded by concrete and, and the excellent mechanical properties that characterise steel make it an ideal composite for all manner of structures. One of the main weaknesses of this material, however, is that when the concrete is exposed to aggressive environments, in particular high concentrations of chloride ions or carbon dioxide, reinforcing steel corrodes, shortening service life. This article reviews the state of the art on concrete durability, along with the conditions that affect its useful life by inducing reinforcing steel corrosion. It also discusses the prevention and control methods, in particular electrochemical prevention and rehabilitation techniques, that have been developed to mitigate the problem.

    El hormigón armado se ha convertido en el material más utilizado a nivel mundial en el sector de la construcción. La combinación de las altas prestaciones a resistencia a la compresión que ofrece el hormigón y las excelentes propiedades mecánicas del acero lo hacen el material compuesto ideal para aplicaciones estructurales. Sin embargo, uno de los mayores problemas que afecta la vida útil del hormigón es la corrosión del acero de refuerzo, la cual se presenta cuando el hormigón se encuentra expuesto a ambientes agresivos, en especial frente a la exposición a iones cloruros y/o dióxido de carbono. Este trabajo revisa el estado del conocimiento con respecto a la durabilidad del hormigón enfatizando en los fenómenos que afectan su durabilidad y generan la corrosión del acero de refuerzo, adicionalmente se incluyen los métodos de prevención y control que se han desarrollado para mitigar el problema, en particular los relacionados con las técnicas electroquímicas de prevención y rehabilitación.

  20. New approaches to building pathology and durability

    CERN Document Server

    2016-01-01

    This book presents a collection of recent research works intended to assist in the effective management of service loss. It develops and evaluates methodologies for the assessment of defects and failures, and proposes methodologies for preventing and mitigating building defects. As such, the book will appeal to a broad readership of scientists, practitioners, students and lecturers.

  1. Durable temperature sensor for extreme environments

    International Nuclear Information System (INIS)

    A number of pyrometallurgical processes are operated without continuous measurement of the process temperature. In most cases this is due to the coupling of extremely high temperatures with chemically corrosive environments. Since the classical thermocouple must operate at these conditions, its life is usually very short and normally only serves for batch measurements. In recent years the evolution of infrared pyrometers has led to an increasing use of these instruments to monitor process temperatures. They are not however without drawbacks. They require a clear line of sight and their lenses must be clean. Moreover, the dusty nature of such environments can lead to changing emissivities and faulty readings. In an effort to overcome these deficiencies and provide continuous and accurate readings of temperature we developed and tested a novel temperature-sensing device that is durable and long lasting. This new sensor is based on heat pipe technology, which involves the evaporation and condensation of a working fluid within the pipe. The leading portion (i.e. evaporator) of the probe is inserted into the process chamber while the other portion (i.e. condenser) of the probe protrudes on the outside of the chamber. By virtue of the superconducting nature of the probe, the overall operating temperature of the probe can be regulated by controlling the cooling of the condenser (typically with air). Since the probe can be made to operate within a temperature range that is safe for the materials of construction of the probe, its life can be in the order of months. A calibration of the operating temperature of the probe with actual process temperature is used to provide continuous process temperature. As the process temperature changes so does the heat pipe temperature. Numerous tests on lab scale probes have shown this unit to be viable. Moreover, a series of plant trials at Cominco in the copper drossing furnace, the Kivcet smelter, and a zinc roaster have yielded

  2. More Durable Tracks for Heavy Vehicles

    Science.gov (United States)

    Collins, Earl R., Jr.

    1987-01-01

    Tie bars instead of threaded fasteners make track throwing less likely. Proposed undercarriage for tank or bulldozer has flanged edges to prevent rocks and other road debris from getting caught in track drive and damaging or casting off track. Improved track has no threaded fasteners to be loosened by road shock and vibration. Continuous chain of floating guide bars articulated at web junctions. Pins replace bolted connections. Guide bars and flanges on vehicle keep out stones.

  3. Bases for extrapolating materials durability in fuel storage pools

    International Nuclear Information System (INIS)

    A major body of evidence indicates that zirconium alloys have the most consistent and reliable durability in wet storage, justifying projections of safe wet storage greater than 50 y. Aluminum alloys have the widest range of durabilities in wet storage; systematic control and monitoring of water chemistry have resulted in low corrosion rates for more than two decades on some fuels and components. However, cladding failures have occurred in a few months when important parameters were not controlled. Stainless steel is extremely durable when stress, metallurgical and water chemistry factors are controlled. LWR SS cladding has survived for 25 y in wet storage. However, sensitized, stressed SS fuels and components have seriously degraded in fuel storage pools (FSPs) at ∼ 30 C. Satisfactory durability of fuel assembly and FSP component materials in extended wet storage requires investments in water quality management and surveillance, including chemical and biological factors. The key aspect of the study is to provide storage facility operators and other decision makers a basis to judge the durability of a given fuel type in wet storage as a prelude to basing other fuel management plans (e.g. dry storage) if wet storage will not be satisfactory through the expected period of interim storage

  4. Enhanced stress durability of nano resonators with scandium doped electrodes

    International Nuclear Information System (INIS)

    To explore mechanical stress durability of thin aluminum-scandium (AlSc) films, 0.86 GHz nano resonators with AlSc electrodes have been manufactured. Four different samples have been prepared altering the Sc content in the alloy between 0.0% and 2.5%. A final lift-off step accomplished manufacture procedure of the devices. The resonators have been operated with heavy load to determine power durability. The resonators with AlSc electrodes show increased power durability compared to conventional Al metallized devices. Texture and grain structure of all films have been investigated by means of electron backscatter diffraction (EBSD) and atomic force microscopy (AFM). Material fatigue of electrodes has been visualized by scanning electron microscopy (SEM). The refined grain structure of these alloys can explain the enhanced mechanical stress durability of AlSc electrodes. - Research Highlights: →Enhanced power durability of SAW devices with Sc doped electrodes. →Refined grain structure of Sc doped Al films. →Sudden device breakdown of highly Sc doped devices.

  5. Temperature induced effects on the durability of MR fluids

    International Nuclear Information System (INIS)

    Although commercial MR fluids exist for quite some time now and the feasibility as well as the advantages of the MR technology have been demonstrated for several applications by a variety of MR actuator prototypes, a sustainable market break-through of brake and clutch applications utilizing the shear mode is still missing. Essential impediments are the marginal knowledge about the durability of the MR technology. To overcome this situation, a long-term measurement system was developed for the durability analysis of MR fluid formulations within a technical relevant scale with respect to the volume of MR fluid and the transmitted torque. The focus of the presented series of measurements is given to the analysis of temperature induced effects on the durability. In this context four different failure indicators can be distinguished, namely an apparent negative viscosity, deviations in torque data obtained from different measurements as well as a pressure increase and a drop in the on-state torque. The measurement data of the present durability experiments indicate a significant dependency of the attainable energy intake density on the temperature. The aim of such durability tests is to establish a reliable data base for the industry to estimate the life-time of MR devices.

  6. Spray-on superhydrophobic coatings with high mechanical durability for anti-corrosion and anti-soiling applications

    Science.gov (United States)

    Schaeffer, Daniel A.; Polizos, Georgios; Smith, D. Barton; Rajic, Slobodan; Datskos, Panos G.; Hunter, Scott R.

    2014-10-01

    A superhydrophobic (SH) surface has many characteristics - of which are its self-cleaning and anti-corrosion functionalities - that are desirable across various industries. A superhydrophobic surface utilizes the right combination of surface chemistry and roughness that force water droplets to form high water contact angles (CA). This in turn allows droplets to easily roll off and pick up dirt and debris across the surface while also preventing water from penetrating the surface. We have developed a simple yet durable spray-on coating based on functionalized SiO2 nanoparticles that can easily be applied to surfaces including, but not limited to, optical sensors, photovoltaics, sights and lenses, textiles, construction materials, and electronic devices. In addition, these coatings exhibit practical mechanical and environmental durability that allow prolonged use of the coatings in harsh environments.

  7. Properties and durability of metakaolin blended cements

    Directory of Open Access Journals (Sweden)

    Ezzat, El-Sayed

    2010-09-01

    Full Text Available This paper evaluates the optimal calcination temperature and replacement ratio to ensure high metakaolin (MK pozzolanicity in blended cement. The MK used was prepared by firing two types of local at temperatures ranging from 700 to 850 ºC. Dry blends of ordinary Portland cement (OPC and varying proportions of MK were mixed with the amount of water required to ensure optimal consistency of the resulting pastes. The specimens were cured at 100% RH for 24 h and then immersed in water for 3, 7, 28, 90 or 180 days. At each test time, the degree of hydration and compressive strength of the hardened cement pastes were measured The findings showed that the most suitable calcination temperature to obtain metakaolin is 700 ºC, while the optimal replacement ratio ranges from 25 to 30%. DTA was used to determine the phases comprising the hydration products forming at the ages studied. Pure OPC and OPC-MK specimens were immersed in 3% NaCl and 5% MgSO4 solutions for 30, 90 and 180 days to measure their durability. The OPC-MK pastes immersed in the 3% NaCl solution were observed to be highly resistant to chloride attack.

    El presente trabajo evalúa el comportamiento puzolánico de metacaolín (MK, producto de la calcinación a distintas temperaturas de dos tipos de caolín local de composiciones químicas diferentes, al incorporarse al cemento en diferentes proporciones. Se preparó un cemento adicionado mediante la mezcla en seco de cemento Portland ordinario (OPC y metacaolín (MK, a los que se añadió la cantidad óptima de agua para obtener una pasta de la consistencia deseada. Las probetas se curaron a una HR del 100% durante 24 horas, sumergiéndose posteriormente en agua durante 3, 7, 28, 90 o 180 días. A cada tiempo de ensayo se controló el grado de hidratación de las pastas endurecidas y se comprobó la resistencia a la compresión de las probetas cúbicas a las edades de curado establecidas. Los resultados obtenidos indican que la

  8. Durability/life of fiber composites in hygrothermomechanical environments

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1982-01-01

    Statistical analysis and multiple regression were used to determine and quantify the significant hygrothermomechanical variables which influence the tensile durability/life (cycle loading, fatigue) of boron-fiber/epoxy-matrix (B/E) and high-modulus-fiber/epoxy-matrix (HMS/E) composites. The use of the multiple regression analysis reduced the variables from fifteen, assumed initially, to six or less with a probability of greater than 0.999. The reduced variables were used to derive predictive models for compression and intralaminar shear durability/life of B/E and HMS/E composites assuming isoparametric fatigue behavior. The predictive models were subsequently generalized to predict the durability/life of graphite/fiber-r generalized model is of simple form, predicts conservative values compared with measured data and should be adequate for use in preliminary designs. Previously announced in STAR as N82-14287

  9. Effects of slag fineness on durability of mortars

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In recent years, the usages of by-products and wastes in industry have become more important. The importance of the sustainable development is also of increasing. The utilizations of wastes, as mineral admixture or fine aggregate, reduce the consumption of the natural resources and improve the durability of concrete. In this study, the effect of the fineness on the high temperature and sulphate resistances of concrete mortar specimens, produced with ground granulated blast-furnace slag (GBFS)replacing cement, is investigated. The compressive and flexural strength test results for all series related to durability effects,exposing temperature and solutions, exposure times for these durability effects, slag content and fineness are discussed. Consequently, the optimum slag contents are determined for producing the sulphate and high temperature resistant mortars.

  10. Review of durability of cementitious engineered barriers in repository environments

    International Nuclear Information System (INIS)

    This report is concerned with the durability of cementitious engineered barriers in a repository for low and intermediate level nuclear waste. Following the introduction the second section of the review identifies the environmental conditions associated with a deep, hard rock repository for ILW and LLW that are relevant to the durability of cementitious barriers. Section three examines the microstructure and macrostructure of cementitious materials and considers the physical and chemical processes of radionuclide immobilization. Potential repository applications and compositions of cementitious materials are reviewed in Section four. The main analysis of durability is dealt with in Section five. The different types of cementitious barrier are considered separately and their most probable modes of degradation are analysed. Concluding remarks that highlight critical technical matters are given in Section six. (author)

  11. The phenomenon of durability variable dies for aluminum extrusion profiles

    Directory of Open Access Journals (Sweden)

    J. Borowski

    2016-04-01

    Full Text Available Extrusion dies are usually regenerated several times (min 4 times. The phenomenon of extended life after each regenerative nitriding process has not been explained. In this work, the regeneration process of dies used in the extrusion of aluminium profiles has been presented. In the article, it was sought to explain the cause of increased die durability after the third or fourth nitriding. Also in this work is presented an analysis of the influence of the parameters of gas nitriding with the ZeroFlow method on hardness of dies. Results were verified under industrial conditions at extrusion company, comparing the durability of the dies nitrided with the ZeroFlow method with so-far-used dies nitrided in the commercial way. An increase of the dies durability was achieved after a single ZeroFlow nitriding.

  12. Stirling engine - Approach for long-term durability assessment

    Science.gov (United States)

    Tong, Michael T.; Bartolotta, Paul A.; Halford, Gary R.; Freed, Alan D.

    1992-01-01

    The approach employed by NASA Lewis for the long-term durability assessment of the Stirling engine hot-section components is summarized. The approach consists of: preliminary structural assessment; development of a viscoplastic constitutive model to accurately determine material behavior under high-temperature thermomechanical loads; an experimental program to characterize material constants for the viscoplastic constitutive model; finite-element thermal analysis and structural analysis using a viscoplastic constitutive model to obtain stress/strain/temperature at the critical location of the hot-section components for life assessment; and development of a life prediction model applicable for long-term durability assessment at high temperatures. The approach should aid in the provision of long-term structural durability and reliability of Stirling engines.

  13. Durability of monopolar Teflon-coated electromyographic needles.

    Science.gov (United States)

    Mikolich, L M; Waylonis, G W

    1977-10-01

    The results of a two-year study on durability and cause of failure of electromyographic monopolar electrodes are reported. The electrodes were obtained from the regular stock of three different manufacturing sources. Durability is defined on the basis of the number of patients that could be examined before failure. The range was 3 to 110 with the averages 19.7, 33.8, and 62.5 for the three different manufacturers. Common causes of electrode failure included: Teflon retraction, 40.6%; tip dullness or burrs, 34.8%; structural failure of wire or pin, 13.1%; electrical artifacts, 9.7%; and bending of needle shank, 5.7%. Variations in manufactures' tip contour and bevel correlated with tip durability. PMID:907451

  14. Antisuperbug Cotton Fabric with Excellent Laundering Durability.

    Science.gov (United States)

    Yu, Ming; Wang, Ziqiang; Lv, Min; Hao, Rongzhang; Zhao, Rongtao; Qi, Lihua; Liu, Shima; Yu, Chuhong; Zhang, Bowu; Fan, Chunhai; Li, Jingye

    2016-08-10

    Multidrug-resistant superbugs are currently a severe threat to public health. Here, we report a novel kind of antisuperbug material prepared by irradiation induced graft polymerization of 1-butyl-3-vinyl imidazole chloride onto cotton fabric. The reduction of superbugs on this fabric is higher than 99.9%. Attributed to the strong covalent bonding between the graft chains and the cellulose macromolecules, the antisuperbug performance did not decrease even after 150 equiv of domestic laundering cycles. Covalent bonding also prevented the release of the antibacterial groups during application and guarantees the safety of the material, which was proved by animal skin irritation and acute oral toxicity tests. PMID:27464074

  15. Durability Quality Research of Concrete Containing Solar PV Cells

    OpenAIRE

    Chao Sao-Jeng; Cheng An; Hsu Hui-Mi; Chang Jia-Ruey; Teng Li-Wei; Chen Sung-Ching

    2015-01-01

    In this article we demonstrated the study results of durability quality of concrete containing waste solar PV cells. The study used alkali activator to improve the activity of alkali-activated materials in solar PV cells so as to replace Portland cement as binder in concrete. By using sodium hydroxide as an alkali-activator, a high-pH environment is generated to excite the binding characteristics of alkali-activated materials in solar PV cells, and thus develops better durability of the mixes...

  16. Durability evaluation method on rebar corrosion of reinforced concrete

    International Nuclear Information System (INIS)

    In this paper, method on the durability evaluation in nuclear power plant concrete structures was investigated. In view of the importance of evaluating the degree of deterioration of reinforced concrete structures, relationships should be formulated among the number of years elapsed, t, the amount of action of a deteriorative factor, F, the degree of material deterioration, D, and the performance of the structure, P. Evaluation by PDFt diagrams combining these relationships may be effective. A detailed procedure of durability evaluation for a reinforced concrete structure using PDFt concept is presented for the deterioration of rebar corrosion caused by neutralization and penetration of salinity by referring to the recent papers. (author)

  17. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Silaban, A.; Harrison, D.P. (Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Chemical Engineering)

    1989-05-02

    AMAX Research Development Center (AMAX R D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such as size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  18. Utilization of Durability Criterion to Develop Automotive Components

    DEFF Research Database (Denmark)

    Ricardo, Luiz Carlos Hernandes

    2010-01-01

    Today the automotive companies must reduce the time to development of new products with improvement in performance, durability and low cost reductions where possible. To achieve this goal the carmakers need to improve the design criterion of car systems like body, chassis and suspension components....... This paper will present a review of the techniques used in the automotive industry regarding durability before mentioned systems. The paper will present the procedures to obtain the spectrum loading to use in finite element analysis and the validation in laboratory and proving grounds....

  19. Corporate social responsibility, durable-goods and firm profitability

    OpenAIRE

    Goering, Gregory E

    2010-01-01

    Utilizing a two-period durable-goods framework, we show that in uncommitted sales markets a firm may earn higher profits as it increases its level of corporate social responsibility (CSR). We find that this occurs even though CSR has no direct impact other than increasing the durable-goods firm's manufacturing costs. We show that in sales markets, CSR may allow the firm to credibly commit itself to lower production in the future. This, in turn, can enhance their profits even though the CSR ac...

  20. Monetary Policy with Sectoral Linkages and Durable Goods

    DEFF Research Database (Denmark)

    Petrella, Ivan; Rossi, Raffaele; Santoro, Emiliano

    -off as it emerges in otherwise standard two-sector models. We compare the welfare properties of a timeless-perspective monetary policy with the performance of simple instrumental rules that adjust the policy rate in response to the output gap and alternative aggregate measures of final goods price...... inflation. Aggregating durable and non-durable inflation depending on the relative degrees of sectoral price stickiness may induce a severe bias. Input materials attenuate the response of sectoral inflations to movements in the real marginal costs, so that the effective slopes of the sectoral supply...

  1. Durable PROX catalyst based on gold nanoparticles and hydrophobic silica

    KAUST Repository

    Laveille, Paco

    2016-01-20

    3 nm gold nanoparticles (Au NP) obtained by direct chemical reduction of AuPPh3Cl in the presence of methyl-terminated silica exhibit superior durability for low temperature CO oxidation in the presence of hydrogen (PROX). The activity of hydrophobic Au/SiO2-R972 indeed appears much more stable with time-on-stream than those of the OH-terminated, hydrophilic Au/TiO2 and Au/Al2O3 catalysts, with similar Au NP size. This enhanced stability is attributed to the peculiar catalyst surface of Au/SiO2-R972. Not only may the support hydrophobicity concentrate and facilitate reactant adsorption and product desorption over Au NP, but methyl-terminated SiO2-R972 likely also inhibits carbonatation of the Au/support interface. Hence, at a temperature at which H2/H2O “cleaning” of the carbonate-contaminated Au/Al2O3 and Au/TiO2 surface is inefficient (< 100°C), passivated Au/SiO2-R972 displays much more stable PROX activity. Besides, the virtual absence of surface hydroxyl groups, which provide sites for water formation in H2/O2 atmospheres, can also account for the improved PROX selectivity (>85%) observed over Au/SiO2-R972. This new example, of CO oxidation activity of gold nanoparticles dispersed over a hydrophobic, “inert” support, clearly emphasizes the role of hydrogen as a promoter for the gold-catalyzed oxidation of CO at low temperature. Unlike support-mediated oxygen activation, hydrogen-only mediated oxygen activation takes full advantage of the hydrophobic surface, which is much more resistant against CO2 and thus remains free of poisonous carbonate species, as compared with hydroxyl-terminated catalysts. Hence, although the absence of surface hydroxyl groups prevents the hydrophobic Au/SiO2-R972 catalyst to reach the state-of-the-art activities initially displayed by Au/TiO2 and Au/Al2O3, it brings long-term stability with time-on-stream and superior selectivity, which opens up promising perspectives in the development of viable PROX catalysts based on gold.

  2. Rape prevention

    Science.gov (United States)

    Date rape - prevention; Sexual assault - prevention ... Centers for Disease Control and Prevention (CDC). Sexual assault and STDs. In: Sexually transmitted diseases treatment guidelines, 2010. MMWR Recomm Rep . 2010;17(59)(RR-12):90- ...

  3. Durability Quality Research of Concrete Containing Solar PV Cells

    Directory of Open Access Journals (Sweden)

    Chao Sao-Jeng

    2015-01-01

    Full Text Available In this article we demonstrated the study results of durability quality of concrete containing waste solar PV cells. The study used alkali activator to improve the activity of alkali-activated materials in solar PV cells so as to replace Portland cement as binder in concrete. By using sodium hydroxide as an alkali-activator, a high-pH environment is generated to excite the binding characteristics of alkali-activated materials in solar PV cells, and thus develops better durability of the mixes. The conclusions were made on effect of this cement replacement. As a result, we identified the durability for those of 16 concrete specimens predefined and made to consider various possible control factors. The conclusions also depicted that all experiments but the drying shrinkage may be helpful with the suitable use of control factors as far as concerning the recycled solar PV cells for mixing in concrete. In other words, the durability quality of concrete may be partially unacceptable of containing solar PV cells.

  4. The behavior of the MR fluid during durability test

    International Nuclear Information System (INIS)

    The article describes results of durability test of a magnetorheological fluid (MRF), which was carried out in rheometer of own design. The rheometer design enables to measure the rheological properties of MR fluid and to expose it to a long-term loading simultaneously, without any manipulation of the measured sample. During the durability test a change of the two most important parameters of Bingham model describing the behavior of MR fluids can be followed – dynamic viscosity and yield stress. In this paper the yield stress and viscosity were evaluated depending on temperature in OFF-state. The results show a significant change of yield strength during durability test depending on temperature of loading. Dependence of yield stress on temperature was proved. The viscosity decreased by 36% from its initial value after the dissipation of 9÷20kJcm−3 from total 1.2 MJcm−3 and then has remained the same until the end of durability test. Viscosity was evaluated depending on temperature.

  5. Linseed oil for durability improvement of lime-metakaolin mortar

    Czech Academy of Sciences Publication Activity Database

    Nunes, Cristiana Lara; Slížková, Zuzana

    Tokyo: Japan Concrete Institute, 2013, s. 351-358. ISBN 978-4-86384-041-6. [International conference on concrete sustainability /1./. Tokyo (JP), 27.05.2013-29.05.2013] R&D Projects: GA MK(CZ) DF11P01OVV008 Keywords : linseed oil * hydrophobicity * durability * lime-metakaolin Subject RIV: AL - Art, Architecture, Cultural Heritage

  6. Durability Issues and Status of PBI-Based Fuel Cells

    DEFF Research Database (Denmark)

    Jakobsen, Mark Tonny Dalsgaard; Jensen, Jens Oluf; Cleemann, Lars Nilausen;

    2016-01-01

    This chapter briefly reviews durability and stability issues with key materials and components for HT-PEMFCs, including the polymer membrane, the doping acid, the electrocatalyst, the catalyst support and bipolar plates. Degradation mechanisms and their dependence on fuel cell operating conditions...

  7. Durability design of concrete structures, Part 1: Analysis fundamentals

    Directory of Open Access Journals (Sweden)

    Folić Radomir

    2009-01-01

    Full Text Available Concrete structures (CS are designed so that they can satisfy requirements regarding safety, serviceability, durability and aesthetics throughout their design service life. Present design procedures regarding CS required by national or international codes and standards such as Model Code Euro International Committee of Concrete (1993 now Federation Internationale du Beton (FIB, Eurocodes, ACI, RILEM, etc. are predominantly based on strength principles and limit state formulation. The durability aspect is a natural extension of the classical resistance verification where deterioration effects are normally neglected. The reliability is assessed through the given performance that must be delivered within the design service life, the so-called performance-based design. This approach can be adopted for a performance based on service life design. In the recent years design is related to durability through the analysis of carbonation, resistance to chloride ingress, improved freezing and thawing resistance, etc. The review of literature and some recommendations are presented referring to the design of structures aiming to attain greater durability of CS. The accent is put on the theory of reliability, failure probability and service life probability. The basics of this analysis are given through the principles of performances and service life, and deterministic and scholastic methods using the lifetime safety factor.

  8. DURABILITY AND BREAKAGE OF FEED PELLETS DURING REPEATED ELEVATOR HANDLING

    Science.gov (United States)

    Pelleting of animal feeds is important for improved feeding efficiency and for convenience of handling. Pellet quality impacts the feeding benefits for the animals and pellet integrity during handling. To determine the effect of repeated handling on feed pellet breakage and durability, a 22.6-t (100...

  9. Ancient analogues concerning stability and durability of cementitious wasteform

    International Nuclear Information System (INIS)

    The history of cementitious materials goes back to ancient times. The Greeks and Romans used calcined limestone and later developed pozzolanic cement by grinding together lime and volcanic ash called open-quotes pozzolanclose quotes which was first found near Port Pozzuoli, Italy. The ancient Chinese used lime-pozzolanic mixes to build the Great Wall. The ancient Egyptians used calcined impure gypsum to build the Great Pyramid of Cheops. The extraordinary stability and durability of these materials has impressed us, when so much dramatically damaged infrastructure restored by using modern portland cement now requires rebuilding. Stability and durability of cementitious materials have attracted intensive research interest and contractors' concerns, as does immobilization of radioactive and hazardous industrial waste in cementitious materials. Nuclear waste pollution of the environment and an acceptable solution for waste management and disposal constitute among the most important public concerns. The analogy of ancient cementitious materials to modern Portland cement could give us some clues to study their stability and durability. This present study examines selected results of studies of ancient building materials from France, Italy, China, and Egypt, combined with knowledge obtained from the behavior of modern portland cement to evaluate the potential for stability and durability of such materials in nuclear waste forms

  10. Durable Tactile Glove for Human or Robot Hand

    Science.gov (United States)

    Butzer, Melissa; Diftler, Myron A.; Huber, Eric

    2010-01-01

    A glove containing force sensors has been built as a prototype of tactile sensor arrays to be worn on human hands and anthropomorphic robot hands. The force sensors of this glove are mounted inside, in protective pockets; as a result of this and other design features, the present glove is more durable than earlier models.

  11. Recent advances in the mechanical durability of superhydrophobic materials.

    Science.gov (United States)

    Milionis, Athanasios; Loth, Eric; Bayer, Ilker S

    2016-03-01

    Large majority of superhydrophobic surfaces have very limited mechanical wear robustness and long-term durability. This problem has restricted their utilization in commercial or industrial applications and resulted in extensive research efforts on improving resistance against various types of wear damage. In this review, advances and developments since 2011 in this field will be covered. As such, we summarize progress on fabrication, design and understanding of mechanically durable superhydrophobic surfaces. This includes an overview of recently published diagnostic techniques for probing and demonstrating tribo-mechanical durability against wear and abrasion as well as other effects such as solid/liquid spray or jet impact and underwater resistance. The review is organized in terms of various types of mechanical wear ranging from substrate adhesion, tangential surface abrasion, and dynamic impact to ultrasonic processing underwater. In each of these categories, we highlight the most successful approaches to produce robust surfaces that can maintain their non-wetting state after the wear or abrasive action. Finally, various recommendations for improvement of mechanical wear durability and its quantitative evaluation are discussed along with potential future directions towards more systematic testing methods which will also be acceptable for industry. PMID:26792021

  12. Climatic durability of modern assembly technologies in electronics

    Czech Academy of Sciences Publication Activity Database

    Žák, P.; Kreislová, K.; Majtás, Dušan

    Frankfurt am Main: DECHEMA, 2014. ISBN 978-3-89746-159-8. [EUROCORR. European corrosion congress. Pisa (IT), 08.09.2014-12.09.2014] R&D Projects: GA MŠk(CZ) LO1219 Keywords : climatic durability * alloys * electrical properties * mechanical properties Subject RIV: AL - Art, Architecture, Cultural Heritage

  13. Durable and Sustainable Road Constructions for Developing Countries

    NARCIS (Netherlands)

    Molenaar, A.A.A.

    2013-01-01

    This paper discusses the possibilities to build durable and sustainable pavement structures in developing countries. Attention will be paid to geometric design aspects which have a significant effect on pavement life. Following this attention will be paid to the importance of controlling wheel loads

  14. The Effects of Sensitization and Habituation in Durable Goods Markets

    NARCIS (Netherlands)

    G. Liberali (Guilherme); T.S. Gruca (Thomas); W.M. Nique (Walter)

    2011-01-01

    textabstractWe develop a model to study the impact of changes in price sensitivity on the firm as it introduces multiple generations of a durable product where unit costs are a convex function of quality. We incorporate the psychological processes of sensitization and habituation into a model of dis

  15. Durable chemical sensors based on field-effect transistors

    NARCIS (Netherlands)

    Reinhoudt, D.N.

    1995-01-01

    The design of durable chemical sensors based on field-effect transistors (FETs) is described. After modification of an ion-sensitive FET (ISFET) with a polysiloxane membrane matrix, it is possible to attach all electroactive components covalently. Preliminary results of measurements with a sodium-se

  16. Durable Catalysts for High Temperature Proton Exchange Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Durability of proton exchange membrane fuel cells (PEMFCs) is recognized as one of the most important issues to be addressed before the commercialization. The failure mechanisms are not well understood, however, degradation of carbon supported noble metal catalysts is identified as a major failure...

  17. Low viscosity automatic transmission fluids with enhanced friction durability

    Institute of Scientific and Technical Information of China (English)

    Kenji Yatsunami; Samuel H. Tersigni; TANG Hong- zhi; Lee D. Saathoff; Christopher S. Cleveland; Mark Jones

    2009-01-01

    This study focused on the development of a new low viscosity automatic transmission fluid (ATF) with enhanced friction durability to meet the needs of new step type automatic transmissions. Recent high fuel prices encourage increased efficiency in the driveline, including the transmission. Reduction in fluid viscosity and wider use of slip control in torque con-verter clutches are two ways to practically improve fuel efficiency. Increased torque and more shifting is seen with a variety of new transmission hardware platforms, such as wet starting clutches, dual clutches and seven - or eight - speed ATs.This suggests the need for enhanced levels of friction durability from the ATF. The new challenge from this hardware for the ATF formulator lies in the need to simultaneously meet the wear, friction durability and torque capacity requirements at low viscosity in a cost- effective manner. This report introduced a new low viscosity fluid that represents a different commercial ATF formulation style. The new chemistry employs a low viscosity for increased fuel economy, while easily doubling the friction durability of current conven-tional ATFs and offering higher torque and better EP.

  18. Measuring happiness: from fluctuating happiness to authentic-durable happiness.

    Science.gov (United States)

    Dambrun, Michaël; Ricard, Matthieu; Després, Gérard; Drelon, Emilie; Gibelin, Eva; Gibelin, Marion; Loubeyre, Mélanie; Py, Delphine; Delpy, Aurore; Garibbo, Céline; Bray, Elise; Lac, Gérard; Michaux, Odile

    2012-01-01

    On the basis of the theoretical distinction between self-centeredness and selflessness (Dambrun and Ricard, 2011), the main goal of this research was to develop two new scales assessing distinct dimensions of happiness. By trying to maximize pleasures and to avoid displeasures, we propose that a self-centered functioning induces a fluctuating happiness in which phases of pleasure and displeasure alternate repeatedly (i.e., Fluctuating Happiness). In contrast, a selfless psychological functioning postulates the existence of a state of durable plenitude that is less dependent upon circumstances but rather is related to a person's inner resources and abilities to deal with whatever comes his way in life (i.e., Authentic-Durable Happiness). Using various samples (n = 735), we developed a 10-item Scale measuring Subjective Fluctuating Happiness (SFHS) and a 13-item scale assessing Subjective Authentic-Durable Happiness (SA-DHS). Results indicated high internal consistencies, satisfactory test-retest validities, and adequate convergent and discriminant validities with various constructs including a biological marker of stress (salivary cortisol). Consistent with our theoretical framework, while self-enhancement values were related only to fluctuating happiness, self-transcendence values were related only to authentic-durable happiness. Support for the distinction between contentment and inner-peace, two related markers of authentic happiness, also was found. PMID:22347202

  19. Measuring Happiness: From Fluctuating Happiness to Authentic-Durable Happiness

    Directory of Open Access Journals (Sweden)

    MichaelDambrun

    2012-02-01

    Full Text Available On the basis of the theoretical distinction between self-centeredness and selflessness (Dambrun & Ricard, 2011, the main goal of this research was to develop two new scales assessing distinct dimensions of happiness. By trying to maximize pleasures and to avoid displeasures, we propose that a self-centered functioning induces a fluctuating happiness in which phases of pleasure and displeasure alternate repeatedly (i.e. Fluctuating Happiness. In contrast, a selfless psychological functioning postulates the existence of a state of durable plenitude that is less dependent upon circumstances but rather is related to a person’s inner resources and abilities to deal with whatever comes his way in life (i.e. Authentic-Durable Happiness. Using various samples (n = 735, we developed a 10-item Scale measuring Subjective Fluctuating Happiness (SFHS and a 13-item scale assessing Subjective Authentic-Durable Happiness (SA-DHS. Results indicated high internal consistencies, satisfactory test-retest validities, and adequate convergent and discriminant validities with various constructs including a biological marker of stress (salivary cortisol. Consistent with our theoretical framework, while self-enhancement values were related only to fluctuating happiness, self-transcendence values were related only to authentic-durable happiness. Support for the distinction between contentment and inner peace, two related markers of authentic happiness, also was found.

  20. A study on management of corporate cash in consumer durable sector

    Directory of Open Access Journals (Sweden)

    Somnath Das

    2015-02-01

    Full Text Available Cash plays essential role in modern business and economy and it is the life blood of all businesses. Therefore, cash management is the art of managing a company’s short-term resources for its ongoing activities, mobilizing funds and optimizing liquidity. Inefficient cash management may lead the company to bankruptcy. In this paper, we highlight different perspectives in which we can control the corporate cash including Cash Conversion Cycle, Cash Holding and Creditworthiness. The term Cash Conversion Cycle can be considered as a length of time between purchase of raw-materials and collection of cash from debtors. Cash holding is one of the most important financial decisions that the manager of the concerned organization has to make for the organizations. In this paper, we try to interlink among different items to control cash so that bankruptcy could be prevented and profitability would be improved by investigating on five companies from Consumer Durable sector.

  1. DURABILITY TESTING OF FLUIDIZED BED STEAM REFORMER (FBSR) WASTE FORMS

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C

    2006-01-06

    Fluidized Bed Steam Reforming (FBSR) is being considered as a potential technology for the immobilization of a wide variety of high sodium aqueous radioactive wastes. The addition of clay and a catalyst as co-reactants converts high sodium aqueous low activity wastes (LAW) such as those existing at the Hanford and Idaho DOE sites to a granular ''mineralized'' waste form that may be made into a monolith form if necessary. Simulant Hanford and Idaho high sodium wastes were processed in a pilot scale FBSR at Science Applications International Corporation (SAIC) Science and Technology Applications Research (STAR) facility in Idaho Falls, ID. Granular mineral waste forms were made from (1) a basic Hanford Envelope A low-activity waste (LAW) simulant and (2) an acidic INL simulant commonly referred to as sodium-bearing waste (SBW). The FBSR waste forms were characterized and the durability tested via ASTM C1285 (Product Consistency Test), the Environmental Protection Agency (EPA) Toxic Characteristic Leaching Procedure (TCLP), and the Single Pass Flow Through (SPFT) test. The durability of the FBSR waste form products was tested in order to compare the measured durability to previous FBSR waste form testing on Hanford Envelope C waste forms that were made by THOR Treatment Technologies (TTT) and to compare the FBSR durability to vitreous LAW waste forms, specifically the Hanford low activity waste (LAW) glass known as the Low-activity Reference Material (LRM). The durability of the FBSR waste form is comparable to that of the LRM glass for the test responses studied.

  2. Durability of fibre reinforced concrete structures exposed to combined mechanical and environmental load

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard

    1999-01-01

    The main conclusions from a research project on durability of cracked fibre reinforced concrete structures exposed to chlorides, water or freeze-thaw are presented. The effect of fibres and cracks on the durability of concrete is studied.......The main conclusions from a research project on durability of cracked fibre reinforced concrete structures exposed to chlorides, water or freeze-thaw are presented. The effect of fibres and cracks on the durability of concrete is studied....

  3. Frost Durability and Strength of Concrete Prepared with Crushed Sand of Different Characteristics

    OpenAIRE

    Zhou, Ming-kai; Liu, Zhan-ao; Chen, Xiao

    2016-01-01

    The influences of fines content, methylene blue (MB) value, and lithology of crushed sand (CS) on frost durability and strength of concrete were investigated, and the frost durability and strength of crushed sand concrete (CSC) and river sand concrete (RSC) were compared. The results show that inclusion of fines improves CSC compressive strength and reduces frost durability of C30 CSC when fines content reaches 10%, whereas it has little negative influence on frost durability of C60 CSC. Incr...

  4. Improved Durability of Electrocatalyst Based on Coating of Carbon Black with Polybenzimidazole and their Application in Polymer Electrolyte Fuel Cells.

    Science.gov (United States)

    Fujigaya, Tsuyohiko; Hirata, Shinsuke; Berber, Mohamed R; Nakashima, Naotoshi

    2016-06-15

    Improvement of durability of the electrocatalyst has been the key issue to be solved for the practical application of polymer electrolyte membrane fuel cells. One of the promising strategies to improve the durability is to enhance the oxidation stability of the carbon-supporting materials. In this report, we describe in detail the mechanism of the stability improvement of carbon blacks (CBs; Vulcan and Ketjen) by coating with polybenzimidazole (PBI). Nitrogen adsorption experiments reveal that the PBI coating of CBs results in the capping of the gates of the CB-micropores by the PBI. Since the surface of the micropores inside the CBs are inherently highly oxidized, the capping of such pores effectively prevents the penetration of the electrolyte into the pore and works to avoid the further oxidation of interior of the micropore, which is proved by cyclic voltammogram measurements. Above mechanism agrees very well with the dramatic enhancement of the durability of the membrane electrode assembly fabricated using Pt on the PBI-coated CBs as an electrocatalyst compared to the conventional Pt/CB (PBI-non coated) catalyst. PMID:27227977

  5. Durable and water-floatable ionic polymer actuator with hydrophobic and asymmetrically laser-scribed reduced graphene oxide paper electrodes.

    Science.gov (United States)

    Kim, Jaehwan; Jeon, Jin-Han; Kim, Hyun-Jun; Lim, Hyuneui; Oh, Il-Kwon

    2014-03-25

    Ionic polymer actuators driven by electrical stimuli have been widely investigated for use in practical applications such as bioinspired robots, sensors, and biomedical devices. However, conventional ionic polymer-metal composite actuators have a serious drawback of poor durability under long-term actuation in open air, mainly because of the leakage of the inner electrolyte and hydrated cations through cracks in the metallic electrodes. Here, we developed a highly durable and water-floatable ionic polymer artificial muscle by employing hydrophobic and asymmetrically laser-scribed reduced graphene oxide paper electrodes (HLrGOP). The highly conductive, flexible, and cost-effective HLrGOP electrodes have asymmetrically smooth hydrophobic outer and rough inner surfaces, resulting in liquid-impermeable and water-floatable functionalities and strong bonding between an ionic polymer and the electrodes. More interestingly, the HLrGOP electrode, which has a unique functionality to prevent the leakage of the vaporized or liquid electrolyte and mobile ions during electrical stimuli, greatly contributes to an exceptionally durable ionic polymer-graphene composite actuator that is a prerequisite for practical applications in active biomedical devices, biomimetic robots, touch-feedback haptic systems, and flexible soft electronics. PMID:24548279

  6. Highly durable silica-coated Pt/carbon nanotubes for proton-exchange membrane fuel cells application

    Science.gov (United States)

    Yaowarat, Wattanachai; Li, Oi Lun Helena; Saito, Nagahiro

    2016-01-01

    Platinum nanoparticles supported on carbon nanotubes (Pt/CNTs) have been used as an electrocatalyst in proton-exchange membrane fuel cells (PEMFCs). These catalysts show higher activity in oxygen reduction reaction in PEMFCs than conventional carbon-black-supported Pt nanoparticles. However, their durability is lower than that of other metal-alloy-based or nonmetal-based catalysts. In this study, Pt/CNTs were synthesized by solution plasma followed by coating with silica layer by the sol-gel method using a cationic surfactant [cetyltrimethylammonium bromide (CTAB)]. This material can be used as a cathode in PEMFCs. The silica layer was coated on the surface of Pt/CNTs to prevent agglomeration and detachment of Pt nanoparticles from carbon nanotubes during operation. The formation of silica layers significantly improved the durability of the Pt/CNT catalysts under acidic conditions. After 300 cycles of the cyclic voltammetry test in 0.5#M sulfuric acid (H2SO4), silica-coated Pt/CNTs increased the durability by 43.0 and 24.0% compared with those of noncoated commercial Pt/C and Pt/CNTs, respectively.

  7. Evolutionary model of an anonymous consumer durable market

    Science.gov (United States)

    Kaldasch, Joachim

    2011-07-01

    An analytic model is presented that considers the evolution of a market of durable goods. The model suggests that after introduction goods spread always according to a Bass diffusion. However, this phase will be followed by a diffusion process for durable consumer goods governed by a variation-selection-reproduction mechanism and the growth dynamics can be described by a replicator equation. The theory suggests that products play the role of species in biological evolutionary models. It implies that the evolution of man-made products can be arranged into an evolutionary tree. The model suggests that each product can be characterized by its product fitness. The fitness space contains elements of both sites of the market, supply and demand. The unit sales of products with a higher product fitness compared to the mean fitness increase. Durables with a constant fitness advantage replace other goods according to a logistic law. The model predicts in particular that the mean price exhibits an exponential decrease over a long time period for durable goods. The evolutionary diffusion process is directly related to this price decline and is governed by Gompertz equation. Therefore it is denoted as Gompertz diffusion. Describing the aggregate sales as the sum of first, multiple and replacement purchase the product life cycle can be derived. Replacement purchase causes periodic variations of the sales determined by the finite lifetime of the good (Juglar cycles). The model suggests that both, Bass- and Gompertz diffusion may contribute to the product life cycle of a consumer durable. The theory contains the standard equilibrium view of a market as a special case. It depends on the time scale, whether an equilibrium or evolutionary description is more appropriate. The evolutionary framework is used to derive also the size, growth rate and price distribution of manufacturing business units. It predicts that the size distribution of the business units (products) is lognormal

  8. Study on durability of concrete in coal mine

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-shun; JIN Zu-quan; SUN Wei; GUAN Xue-mao

    2004-01-01

    There are sulfate and chloride ions corrosion and carbonation to concrete in coal mine. Based on taking test of accelerated carbonation, corrosion of 3.5% weight of NaCl solution and 5% weight of Na2SO4 solution of coal mine concretes, durability of concretes which include spray concrete of C20, high performance concretes of C30 and C50and effect of fly ash on durability have been studied. Results suggest that the coal mineral high performance concretes show good resistance capacities of carbonation, sulfate and chloride corrosion to meet the coal mine construction. And the higher the strength grade is,the better the resistance capacity of corrosion of carbonation is, chloride and sulfate.Moreover, fly ash improves resistance capacity of high performance concrete(HPC) to chloride and sulfate but decreases the resistance capacity of C30's to carbonation and average dynamic modulus.

  9. Durability Challenges for Next Generation of Gas Turbine Engine Materials

    Science.gov (United States)

    Misra, Ajay K.

    2012-01-01

    Aggressive fuel burn and carbon dioxide emission reduction goals for future gas turbine engines will require higher overall pressure ratio, and a significant increase in turbine inlet temperature. These goals can be achieved by increasing temperature capability of turbine engine hot section materials and decreasing weight of fan section of the engine. NASA is currently developing several advanced hot section materials for increasing temperature capability of future gas turbine engines. The materials of interest include ceramic matrix composites with 1482 - 1648 C temperature capability, advanced disk alloys with 815 C capability, and low conductivity thermal barrier coatings with erosion resistance. The presentation will provide an overview of durability challenges with emphasis on the environmental factors affecting durability for the next generation of gas turbine engine materials. The environmental factors include gaseous atmosphere in gas turbine engines, molten salt and glass deposits from airborne contaminants, impact from foreign object damage, and erosion from ingestion of small particles.

  10. Determination of anisotropy to enhance the durability of natural stone

    International Nuclear Information System (INIS)

    Anisotropy is a petrophysical property of natural stone and other construction materials that determines their quality and resistance to decay due to a variety of agents, such as water. A study was conducted on nine types of stone widely used in Spain's built heritage, using six previously defined anisotropy indices. These indices can be used to determine the degree of anisotropy, which helps explain the differential decay observed in stone materials quarried in the same bed and used to build the same structure. The conclusion reached is that anisotropy should be determined in the natural stone used both to restore the architectural heritage and in new construction, since the appropriate choice of material quality ensures greater resistance to decay and, therefore, increased durability. Materials with the lowest possible anisotropy should be selected, as this property governs their hydraulic behaviour: the lower the anisotropy in a material, the better its behaviour in relation to water and the longer its durability

  11. Study on durability of concrete in coal mine

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Jin, Z.; Sun, W.; Guan, X. [Henan Polytechnic University, Jiaozuo (China). Dept. of Resource and Material

    2004-12-01

    There are sulfate and chloride ions corrosion and carbonation of concrete in coal mine. Based on taking test of accelerated carbonation, corrosion of 3.5% weight of NaCl solution and 5% weight of Na{sub 2}SO{sub 4} solution of coal mine concretes, durability of concretes which include spray concrete of C20, high performance concretes of C30 and C50 and effect of fly ash on durability have been studied. Results suggest that the coal mineral high performance concretes show good resistance capacities of carbonation, and sulfate and chloride corrosion to meet the coal mine construction. Moreover, fly ash improves resistance capacity of high performance concrete (HPC) to chloride and sulfate but decreases the resistance capacity of C30's to carbonation and average dynamic modulus. 9 refs., 4 figs., 1 tab.

  12. Cement mixtures containing copper tailings as an additive: durability properties

    Directory of Open Access Journals (Sweden)

    Obinna Onuaguluchi

    2012-12-01

    Full Text Available The effects of copper tailings as an additive, on some durability properties of cement mixtures were investigated. In each mixture, copper tailings addition levels by mass were 0%, 5% and 10%. Compared to the control samples, copper tailings blended pastes showed superior performance against autoclave expansion while insignificant decreases in sulfate resistance of mortars were observed. Copper tailings increased the water absorption and total permeable voids of concretes slightly. However, the compressive and flexural strengths of blended concretes were higher than those of the control samples. Similarly, improved resistance to acid attack and chloride penetration as the copper tailings content of concretes increased were also observed. Results further showed that the ASTM C 1202 rapid chloride permeability test may not be a valid indicator of chloride migration in mixtures containing conductive copper tailings. These results suggest that copper tailings can potentially enhance the durability properties of cement based materials.

  13. MATHEMATICAL MODELING FOR DURABILITY CHARACTERISTICS OF FLY ASH CONCRETE

    Directory of Open Access Journals (Sweden)

    JINO JOHN

    2012-01-01

    Full Text Available This paper presents the results obtained from the mathematical modeling for the durability characteristics of fly ash concrete. A mathematical model is employed to predict the saturated water absorption, permeability, sorpitivity and acid resistance of the concrete containing fly ash as a replacement of cement at a range of 0%, 10%, 20%, 30%, 40% and 50 %. This model is valid for mixes with cement quantity 208 to 416 kg/m3, water cement ratio 0.38 to 0.76, flyash 0 to 208 kg/m3 and cement/ total aggregate ratio varying from 0.11 to 0.22. Fly ash content and water cement ratio are the main parameters which influence the durability characteristics. The predicted mathematical model for saturated water absorption, permeability, sorpitivity and acid resistance produced accurate results for the respective ages when compared with the experimental results.

  14. Durability of Solid Oxide Electrolysis Cells for Syngas Production

    DEFF Research Database (Denmark)

    Sun, Xiufu; Chen, Ming; Liu, Yi-Lin; Hjalmarsson, Per; Ebbesen, Sune Dalgaard; Jensen, Søren Højgaard; Mogensen, Mogens Bjerg; Hendriksen, Peter Vang

    2013-01-01

    Performance and durability of Ni-YSZ supported solid oxide electrolysis cells (SOECs) for co-electrolysis of H2O and CO2 at high current density was investigated. The cells consist of a Ni-YSZ support, a Ni-YSZ electrode, a YSZ electrolyte, and an LSM-YSZ electrode. The durability was examined at...... 800°C and electrolysis current densities of −1 or −1.5 A/cm2 with 60% reactant (H2O + CO2) utilization. The cell voltage degradation showed a strong dependence on the electrolysis current density. Electrochemical characterization of the cells showed that the degradation was mainly related to the LSM...

  15. Moisture Durability with Vapor-Permeable Insulating Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Lepage, R. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2013-09-01

    Exterior sheathing insulation is an effective strategy in increasing the overall R-value of wall assemblies; other benefits include decreasing the effects of thermal bridging and increasing the moisture durability of the built assembly. Vapor-permeable exterior insulation, such as mineral board or expanded polystyrene foam, are one such product that may be used to achieve these benefits. However, uncertainty exists on the effects of inward driven moisture and the interaction of increased sheathing temperatures on the moisture durability of the edifice. To address these concerns, Building Science Corporation (BSC) conducted a series of hygrothermal models for cities representing a range of different climate zones. This report describes the research project, key research questions, and the procedures utilized to analyse the problems.

  16. Moisture Durability with Vapor-Permeable Insulating Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Lepage, R. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2013-09-01

    Exterior sheathing insulation is an effective strategy in increasing the overall R-value of wall assemblies; other benefits include decreasing the effects of thermal bridging and increasing the moisture durability of the built assembly. Vapor-permeable exterior insulation, such as mineral board or expanded polystyrene foam, are one such product that may be used to achieve these benefits. However,uncertainty exists on the effects of inward driven moisture and the interaction of increased sheathing temperatures on the moisture durability of the edifice. To address these concerns, Building Science Corporation (BSC) conducted a series of hygrothermal models for cities representing a range of different climate zones. This report describes the research project, key research questions, and theprocedures utilized to analyse the problems.

  17. High Performance and Durable Low PGM Cathode Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Liu, Jun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shao, Yuyan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cheng, Yingwen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Borup, Rodney L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rockward, Tommy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brosha, Eric Lanich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-17

    There is a strong need to decrease the amount of Pt electrocatalyst used in fuel cells and increase its durability for transportation application. Conventional strategies include Pt nanocrystals and Pt alloy with well-controlled structures, durable carbon support, non-carbon support, etc. We have developed the so-called “metal-metal oxide-carbon” triple junction concept to stabilize Pt and protect carbon from corrosion. It also improved the activity of Pt. The good performance was not achieved in fuel cell test mainly because of the transport issue due to the use of 2D graphene. In this project, our main goal is to demonstrate the concept in fuel cell device test using 3D porous graphene as support so that the transport issue could be addressed.

  18. DURABILITY OF MIXED MORTAR LINING CONTAINING DREGS-GRITS

    Directory of Open Access Journals (Sweden)

    B. P. Zanella

    2014-01-01

    Full Text Available The improper disposal of industrial waste and exploitation of natural resources has resulted in the scarcity of river sand and environmental degradation, such as river erosions and pollution. This study aimed to assess the durability of mixed mortar lining walls and ceilings, containing 0 (default, 10 and 20% of dregs-grits compounds-waste of the pulp industry-in substitution with river sand. This was done with tests that simulated both natural and artificial conditions: Direct solar incidence (testing ultraviolet radiation, attack by spraying solution (salt spray test, natural warming of the walls and ceilings incidence by indirect solar (thermal degradation and residential fires (thermogravimetric test, in compliance with both national and/or international standards. The grout containing dregs-grits compounds showed similarity to standard (0% for testing thermal degradability, thermogravimetric and ultraviolet radiation, but shows significantly less durability when exposed to salty environments.

  19. Durability of concrete structures strengthened with FRP laminates

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the fast freeze-thaw cycling test, the alkaline immersion test, the water immersion test and the wet-thermal exposure test, the influence of aggressive environments on mechanical behavior of FRP was studied. CFRP specimens subjected to aggressive environments showed good durability with no significant degradation in tensile strength and modulus; however, GFRP specimens exhibited a little decrease in mechanical property after aggressive environments exposure. Based on the fast freeze-thaw cycling test and the wet-thermal exposure test, the influence of aggressive environments on the bond behavior between FRP and concrete, mechanical behavior of concrete beams and columns strengthened with FRP laminates was studied. The results showed that the bond strength had a significant decrease compared with those specimens kept at room temperature, and the specimens strengthened with FRP exhibited good durability.

  20. Durability of Advanced Woven Composites in Aerospace Applications

    OpenAIRE

    Patel, Sneha Ramesh

    1999-01-01

    The objective of this project was to evaluate and model the effects of moisture, temperature, and combined hygrothermal aging on the durability of a graphite/epoxy woven composite material system. Imposed environmental and aging conditions were considered to be representative of service conditions for the engine of an advanced subsonic aircraft for which the composite system is a candidate material. The study was designed such that the results could be used in a residual strength based life...

  1. Experimental Studies on the Mechanical Durability of Proton Exchange Membranes

    OpenAIRE

    Li, Yongqiang

    2008-01-01

    Three testing methods are proposed to characterize properties of fuel cell materials that affect the mechanical durability of proton exchange membranes (PEMs). The first two methods involved measuring the in-plane biaxial strength of PEMs and the biaxial hygrothermal stresses that occur in PEMs during hygrothermal cycles. The third method investigated the nonuniform thickness and compressibility of gas diffusion media which can lead to concentrated compressive stresses in the PEM in the thr...

  2. A New Product Growth for Model Consumer Durables

    OpenAIRE

    Frank M. Bass

    2004-01-01

    (This article originally appeared in Management Science, January 1969, Volume 15, Number 5, pp. 215--227, published by The Institute of Management Sciences.) A growth model for the timing of initial purchase of new products is developed and tested empirically against data for eleven consumer durables. The basic assumption of the model is that the timing of a consumer's initial purchase is related to the number of previous buyers. A behavioral rationale for the model is offered in terms of inn...

  3. Energy and durable development: the place of the renewable energies

    International Nuclear Information System (INIS)

    The 29 may 2000, took place at the UNESCO, a colloquium on the place of the renewable energies facing the economic development. This document presents the opening presentation of A. Antolini and L. Jospin and the colloquium papers and debates in the following four domains: the energy challenges of the durable development, the renewable energies sources facing the european directive, the thermal renewable energies (solar, geothermics and biomass) and the greenhouse effect, the world market of the renewable energies. (A.L.B.)

  4. What Drives Replacement of Durable Goods at the Micro Level?

    OpenAIRE

    Viviana Fernández

    2002-01-01

    Technological innovations have contributed over the years to an increasing stock of durable goods - those products that are not immediately consumed but provide a stream of services over a long period of time. Indeed, virtually every household in a modern economy owns a refrigerator, a personal computer and an automobile. Given the inter-temporal nature of replacement decisions, the existing literature has resorted to the technique of dynamic programming, and most recently to the theory of st...

  5. Consumer Durables: Evidence on the Optimality of Usually Doing Nothing.

    OpenAIRE

    Bar-Ilan, Avner; Blinder, Alan S.

    1992-01-01

    The authors argue that lumpy, nonconvex transaction costs are the norm for a wide range of economic decisions, which are thus characterized by inertial behavior. Application of this idea to the consumption of durable goods yields an (S,s) decision rule, which, when aggregated, highlights the different expected behavior of average expenditure per purchase versus the number of purchases. The empirical implications of this rule are presented and compared to other theories. A battery of empirical...

  6. Durability design of concrete structures, Part 1: Analysis fundamentals

    OpenAIRE

    Folić Radomir

    2009-01-01

    Concrete structures (CS) are designed so that they can satisfy requirements regarding safety, serviceability, durability and aesthetics throughout their design service life. Present design procedures regarding CS required by national or international codes and standards such as Model Code Euro International Committee of Concrete (1993) now Federation Internationale du Beton (FIB), Eurocodes, ACI, RILEM, etc. are predominantly based on strength principles and limit state formulation. The durab...

  7. Durability of concrete protected by an acrylic painting

    OpenAIRE

    Aguiar, J. L. Barroso de; Ramos, Amparo C.; Soares, Helena I.

    2005-01-01

    The fast degradation of concrete is a problem that occurs in some structures. In order to have less degradation, the use of protection systems could be recommended. Acrylic paintings have properties that make possible its use as a protection material of concrete. In our study, one concrete that could be classified as a C33/43, was protected with two coats of an acrylic painting. The durability of the protected concrete was studied. Tests made were: capillarity absorption, oxygen perm...

  8. Experimental investigation of the variability of concrete durability properties

    OpenAIRE

    AÏT MOKHTAR, Karim; Torrenti, Jean Michel; BENBOUDJEMA, Farid; Capra, Bruno; CARCASSES, M; Colliat, Jean-Baptiste; CUSSIGH, François; De Larrard, Thomas; LATASTE, JF; Poyet, Stéphane; ROUGEAU, Patrick; Sellier, A.; Trabelsi, A.; Turcry, Philippe

    2013-01-01

    One of the main objectives of the APPLET project was to quantify the variability of concrete properties to allow for a probabilistic performance-based approach regarding the service lifetime prediction of concrete structures. The characterization of concrete variability was the subject of an experimental program which included a significant number of tests allowing the characterization of durability indicators or performance tests. Two construction sites were selected from which concrete spec...

  9. The phenomenon of durability variable dies for aluminum extrusion profiles

    OpenAIRE

    Borowski, J; Wendland, J.

    2016-01-01

    Extrusion dies are usually regenerated several times (min 4 times). The phenomenon of extended life after each regenerative nitriding process has not been explained. In this work, the regeneration process of dies used in the extrusion of aluminium profiles has been presented. In the article, it was sought to explain the cause of increased die durability after the third or fourth nitriding. Also in this work is presented an analysis of the influence of the parameters of gas nitriding with the ...

  10. Durability Properties of Palm Oil Fuel Ash Self Compacting Concrete

    OpenAIRE

    T. Ofuyatan; F. Olutoge; A. Olowofoyeku

    2015-01-01

    Self Compacting Concrete (SCC) is a new innovation in technology that can flow readily into place under its own self weight and fill corner areas of reinforcement structures without the need to vibrate and without segregation of its constitute. The problem of durability of concrete structures due to inadequate compaction by skilled workers has become a source of concern globally. The shortage of skilled manpower, noise and vibration of equipment on construction sites has led to the developmen...

  11. Durable Goods: An Explanation for Their Slow Adjustment

    OpenAIRE

    1991-01-01

    Aggregate expenditure on durable goods responds too slowly to wealth and other aggregate innovations to be consistent with the simplest frictionless version of PIH (permanent income hypothesis). In this paper I present a model of aggregate expenditure on durab1es that builds up from the lumpy nature of microeconomic purchases, and provide evidence supporting its contribution to the resolution of the ?slowness? puzzle. The paper also contains several new results on the problem of dynamic aggre...

  12. Durable strategies to deploy plant resistance in agricultural landscapes

    OpenAIRE

    Fabre, Frédéric; Rousseau, Elsa; Mailleret, Ludovic; Moury, Benoit

    2012-01-01

    The deployment of resistant crops often leads to the emergence of resistance-breaking pathogens that suppress the yield benefit provided by the resistance. Here, we theoretically explored how farmers’ main leverages (resistant cultivar choice, resistance deployment strategy, landscape planning and cultural practices) can be best combined to achieve resistance durability while minimizing yield losses as a result of plant viruses. Assuming a gene-for-gene type of interaction, virus epidemics ar...

  13. Inequality, product durability and the adoption of new technology products

    OpenAIRE

    Gabrielsen, Tommy Staahl

    2001-01-01

    The analysis highlights how inequality and the cost of producing durability influence the degree to which new technology products are adopted in an economy. It is shown that redistribution may both increase and lower technology dispersion. If inequality is large at the outset, redistribution may lower technology dispersion. On the other hand, if inequality is low at the outset, more redistribution will be beneficial for the adoptation of new technology products. For intermediate cases the eff...

  14. DURABLE DEVELOPMENT OF TOURISM AND ITS IMPACT ON THE ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    TONEA ELENA

    2012-05-01

    Full Text Available Tourism is a factor in the degradation and pollution of the environment and of the touristic potential, either by tourist direct pressure on the landscape, flora and fauna or other touristic objectives which can be partially or wholly deteriorated. This can happen due to a misconception about capitalizing and equipping some areas or touristic objectives. That is why promoting some forms of durable development is necessary, as they are based on ecosystems and on the touristic environmental capacity.

  15. Freeze-Thaw Durability of Air-Entrained Concrete

    OpenAIRE

    Huai-Shuai Shang; Ting-Hua Yi

    2013-01-01

    One of the most damaging actions affecting concrete is the abrupt temperature change (freeze-thaw cycles). The types of deterioration of concrete structures by cyclic freeze-thaw can be largely classified into surface scaling (characterized by the weight loss) and internal crack growth (characterized by the loss of dynamic modulus of elasticity). The present study explored the durability of concrete made with air-entraining agent subjected to 0, 100, 200, 300, and 400 cycles of freeze-thaw. T...

  16. Improvement of durable properties of surgical textiles using plasma treatment

    OpenAIRE

    Alay, S.; Goktepe, F.; Souto, A. Pedro; Carneiro, Noémia; F. Fernandes; Dias, Paula

    2007-01-01

    Nowadays one of the important plasmas used in textile industry is Corona discharge, which is applied in air at atmospheric pressure. Corona offers many advantages such as low production costs mainly due to effective energy utilization and minimum waste materials. In this study, the main focus is to use Corona plasma to produce reusable surgical fabrics with durable properties and using chemical agents at low concentrations. Therefore a new more economic production process of surgical fabri...

  17. Product development capability and marketing strategy for new durable products

    OpenAIRE

    Banerjee, Sumitro; David A. Soberman

    2013-01-01

    Our objective is to understand how a firm’s product development capability (PDC) affects the launch strategy for a durable product that is sequentially improved over time in a market where consumers have heterogeneous valuations for quality. We show that the launch strategy of firms is affected by the degree to which consumers think ahead. However, only the strategy of firms with high PDC is affected by the observability of quality. When consumers are myopic and quality is observable, both hi...

  18. The durability of beneficial health effects associated with expressive writing

    OpenAIRE

    Sloan, Denise M.; Feinstein, Brian A.; Marx, Brian P.

    2009-01-01

    This study examined the durability of benefits associated with expressive writing. Sixty-eight college undergraduates completed measures of physical and psychological health at the beginning of their first year and were then randomized to either an expressive writing or a control writing condition. Changes in physical health, psychological health (i.e., depression, stress, and anxiety), and academic performance were assessed two, four, and six months later. Findings indicated that participant...

  19. Serious games et développement durable

    OpenAIRE

    Gagnebien, Anne

    2013-01-01

    Comment expliquer le développement durable aux jeunes générations ? En les faisant jouer ! Cette contribution explore une nouvelle piste de dispositifs qualifiés de ludo-pédagogiques innovants appelés aussi serious games aujourd’hui présentés par les institutions muséales dans les expositions scientifiques, techniques et de société

  20. Cement mixtures containing copper tailings as an additive: durability properties

    OpenAIRE

    Obinna Onuaguluchi; Özgur Eren

    2012-01-01

    The effects of copper tailings as an additive, on some durability properties of cement mixtures were investigated. In each mixture, copper tailings addition levels by mass were 0%, 5% and 10%. Compared to the control samples, copper tailings blended pastes showed superior performance against autoclave expansion while insignificant decreases in sulfate resistance of mortars were observed. Copper tailings increased the water absorption and total permeable voids of concretes slightly. However, t...

  1. Durable Effects of Cognitive Restructuring on Conditioned Fear

    OpenAIRE

    Shurick, Ashley A.; Hamilton, Jeffrey R.; Harris, Lasana T.; Roy, Amy K.; Gross, James J.; Phelps, Elizabeth A.

    2012-01-01

    Studies of cognitive reappraisal have demonstrated that reinterpreting a stimulus can alter emotional responding, yet few studies have examined the durable effects associated with reinterpretation-based emotion regulation strategies. Evidence for the enduring effects of emotion regulation may be found in clinical studies that use cognitive restructuring (CR) techniques in cognitive–behavioral therapy (CBT) to alleviate anxiety. These techniques are based on cognitive theories of anxiety that ...

  2. Use of recycled fine aggregate in concretes with durable requirements.

    Science.gov (United States)

    Zega, Claudio Javier; Di Maio, Angel Antonio

    2011-11-01

    The use of construction waste materials as aggregates for concrete production is highly attractive compared to the use of non-renewable natural resources, promoting environmental protection and allowing the development of a new raw material. Several countries have recommendations for the use of recycled coarse aggregate in structural concrete, whereas the use of the fine fraction is limited because it may produce significant changes in some properties of concrete. However, during the last decade the use of recycled fine aggregates (RFA) has achieved a great international interest, mainly because of economic implications related to the shortage of natural sands suitable for the production of concrete, besides to allow an integral use of this type of waste. In this study, the durable behaviour of structural concretes made with different percentage of RFA (0%, 20%, and 30%) is evaluated. Different properties related to the durability of concretes such as absorption, sorptivity, water penetration under pressure, and carbonation are determined. In addition, the results of compressive strength, static modulus of elasticity and drying shrinkage are presented. The obtained results indicate that the recycled concretes have a suitable resistant and durable behaviour, according to the limits indicated by different international codes for structural concrete. PMID:21775123

  3. Durability testing of heavy ion irradiated crystalline ceramics

    International Nuclear Information System (INIS)

    The purpose of this report is to assess the effects of heavy-ion irradiation on the durability of pyrochlore-rich baseline ceramics and single-phase pyrochlore, zirconolite and brannerite ceramics. Development of a titanate-based crystalline ceramic form to immobilize surplus weapons-useable plutonium for disposition is the mission of the Plutonium Immobilization Project (PIP). A major development and testing activity for this program is performance testing and qualification of the wasteform for a repository. As part of the performance testing, the leaching behavior of the ceramic form must be evaluated to determine the anticipated repository behavior. To study the impact of radiation damage on the performance of the ceramic, the damage must be accelerated using techniques such as 238Pu doping and ion irradiation. The purpose of this report is to assess the effects of heavy-ion irradiation on the durability of pyrochlore-rich baseline ceramics and single-phase pyrochlore, zirconolite and brannerite ceramics. Ion irradiation of ceramic pellet surfaces will transform the outermost several tenths of microns of the surface into a metamict (i.e., noncrystalline) state. Short-term monolithic leach tests on unirradiated and irradiated samples should elucidate any significant differences in the durability of the undamaged crystalline surface versus the damaged metamict surface. Data developed under this task will support a preliminary integrated data report to be supplied to the Office of Civilian Radioactive Waste Management (RW) for use in the license application for the candidate Yucca Mountain repository

  4. Durability Properties of Palm Oil Fuel Ash Self Compacting Concrete

    Directory of Open Access Journals (Sweden)

    T. Ofuyatan

    2015-02-01

    Full Text Available Self Compacting Concrete (SCC is a new innovation in technology that can flow readily into place under its own self weight and fill corner areas of reinforcement structures without the need to vibrate and without segregation of its constitute. The problem of durability of concrete structures due to inadequate compaction by skilled workers has become a source of concern globally. The shortage of skilled manpower, noise and vibration of equipment on construction sites has led to the development of self compacting concrete. This paper presents an experimental study on the durability properties of Self Compacting Concrete with partial placement of Palm Oil Fuel Ash (POFA. Twelve POFA self-compacting concretes of various strength grades were designed at varying percentages of 0, 5, 10, 15, 20, 25 and 30%. The concrete with no placement of ash served as control. Conplast SP432MS was used as superplasticiser in the mix. The experiments are carried out by adopting a water-powder ratio of 0.36. Workability of the fresh concrete is determined by using tests such as: slump flow, T50, V-funnel and L-Box tests. The durability of concrete is tested by acid resistance, sulphate attack and saturated water absorption at the age of 14, 28, 56 and 90 days.

  5. Influences of a New Admixture MX on Concrete Durability

    Institute of Scientific and Technical Information of China (English)

    MA Baoguo; DONG Rongzhen; ZHU Hongbo; ZHANG Li; ZHONG Kaihong; HE Xingyang; LI Zongjin

    2005-01-01

    The performance of concrete with a new admixture MX was studied by using the freeze-thaw cycle, permeability and chemical attack test. The experimental results show that MX improves the durability of concrete. Within the optimum proportion ranges from 0.1%to 1%,the compressive strength of concrete after freeze-thaw is increased by 20%-50%,and Young's modulus can be increased by 3.76-5.64 times.The strength and weight loss of concrete with 0.4%MX are respectively decreased by 28% and 60% after hydrochloric acid attack.The strength and weight loss of concrete with 0.4% MX are decreased by 5%-20% after sulfuric acid and sodium sulfate attack.The permeability of concrete with 1% MX at 28 days can be decreased by more than 30%. The investigation of the negative temperature property of MX and analysis on concrete composition and microstructure by MIP reveal that the heat conduction is resisted and the freezing procedure of solution in concrete pore is retarded due to the adding of MX. Moreover,the pore structure of concrete with MX is improved, thus improving the durability. Based on this study, a resistance model of MX to block the heat and mass transference was proposed, and the mechanism of durability improvement of concrete with MX was explained.

  6. Freeze-thaw durability of air-entrained concrete.

    Science.gov (United States)

    Shang, Huai-Shuai; Yi, Ting-Hua

    2013-01-01

    One of the most damaging actions affecting concrete is the abrupt temperature change (freeze-thaw cycles). The types of deterioration of concrete structures by cyclic freeze-thaw can be largely classified into surface scaling (characterized by the weight loss) and internal crack growth (characterized by the loss of dynamic modulus of elasticity). The present study explored the durability of concrete made with air-entraining agent subjected to 0, 100, 200, 300, and 400 cycles of freeze-thaw. The experimental study of C20, C25, C30, C40, and C50 air-entrained concrete specimens was completed according to "the test method of long-term and durability on ordinary concrete" GB/T 50082-2009. The dynamic modulus of elasticity and weight loss of specimens were measured after different cycles of freeze-thaw. The influence of freeze-thaw cycles on the relative dynamic modulus of elasticity and weight loss was analyzed. The findings showed that the dynamic modulus of elasticity and weight decreased as the freeze-thaw cycles were repeated. They revealed that the C30, C40, and C50 air-entrained concrete was still durable after 300 cycles of freeze-thaw according to the experimental results. PMID:23576906

  7. Durable transparent carbon nanotube films for flexible device components

    International Nuclear Information System (INIS)

    This paper describes a durable carbon nanotube (CNT) film for flexible devices and its mechanical properties. Films as thin as 10 nm thick have properties approaching those of existing electrodes based on indium tin oxide (ITO) but with significantly improved mechanical properties. In uniaxial tension, strains as high as 25% are required for permanent damage and at lower strains resistance changes are slight and consistent with elastic deformation of the individual CNTs. A simple model confirms that changes in electrical resistance are described by a Poisson's ratio of 0.22. These films are also durable to cyclic loading, and even at peak strains of 10% no significant damage occurs after 250 cycles. The scratch resistance is also high as measured by nanoscratch, and for a 50 μm tip a load of 140 mN is required to cause initial failure. This is more than 5 times higher than is required to cause cracking in ITO. The robustness of the transparent conductive coating leads to significant improvement in device performance. In touch screen devices fabricated using CNT no failure occurs after a million actuations while for devices based on ITO electrodes 400,000 cycles are needed to cause failure. These durable electrodes hold the key to developing robust, large-area, lightweight, optoelectronic devices such as lighting, displays, electronic-paper, and printable solar cells. Such devices could hold the key to producing inexpensive green energy, providing reliable solid-state lighting, and significantly reducing our dependence on paper.

  8. Novel Arrangements for High Performance and Durable Dielectric Elastomer Actuation

    Directory of Open Access Journals (Sweden)

    Runan Zhang

    2016-07-01

    Full Text Available This paper advances the design of Rod Pre-strained Dielectric Elastomer Actuators (RP-DEAs in their capability to generate comparatively large static actuation forces with increased lifetime via optimized electrode arrangements. RP-DEAs utilize thin stiff rods to constrain the expansion of the elastomer and maintain the in-plane pre-strain in the rod longitudinal direction. The aim is to study both the force output and the durability of the RP-DEA. Initial design of the RP-DEA had poor durability, however, it generated significantly larger force compared with the conventional DEA due to the effects of pre-strain and rod constraints. The durability study identifies the in-electro-active-region (in-AR lead contact and the non-uniform deformation of the structure as causes of pre-mature failure of the RP-DEA. An optimized AR configuration is proposed to avoid actuating undesired areas in the structure. The results show that with the optimized AR, the RP-DEA can be effectively stabilized and survive operation at least four times longer than with a conventional electrode arrangement. Finally, a Finite Element simulation was also performed to demonstrate that such AR design and optimization can be guided by analyzing the DEA structure in the state of pre-activation.

  9. Occasion Based Promotional Strategies of Consumer Durable Segment in Kerala

    Directory of Open Access Journals (Sweden)

    George Stanley

    2012-06-01

    Full Text Available Occasion Based Marketing is an approach to connect when and why consumers use the product with how they shop for the product. Companies need to realize that their customers are not only different from each other, but are also different from themselves at different times. People have different needs when they are at work and when they are at home or socializing. They act differently during holiday seasons and at regular days. Kerala is highly developed market for consumer products. National as well as International brands have been trying to have a fair share of this market. The study is focused mainly on the promotional strategies of consumer durable companies and retailers during festival season. The high frequency of promotional campaigns by entire consumer durable companies and retailers during festival seasons clearly shows the importance of Occasion Based Marketing in Kerala market. The results of this study would mean that the consumer durable companies and retailers are adapting various promotional strategies to attract deal prone, promotion liking customers.

  10. Freeze-Thaw Durability of Air-Entrained Concrete

    Directory of Open Access Journals (Sweden)

    Huai-Shuai Shang

    2013-01-01

    Full Text Available One of the most damaging actions affecting concrete is the abrupt temperature change (freeze-thaw cycles. The types of deterioration of concrete structures by cyclic freeze-thaw can be largely classified into surface scaling (characterized by the weight loss and internal crack growth (characterized by the loss of dynamic modulus of elasticity. The present study explored the durability of concrete made with air-entraining agent subjected to 0, 100, 200, 300, and 400 cycles of freeze-thaw. The experimental study of C20, C25, C30, C40, and C50 air-entrained concrete specimens was completed according to “the test method of long-term and durability on ordinary concrete” GB/T 50082-2009. The dynamic modulus of elasticity and weight loss of specimens were measured after different cycles of freeze-thaw. The influence of freeze-thaw cycles on the relative dynamic modulus of elasticity and weight loss was analyzed. The findings showed that the dynamic modulus of elasticity and weight decreased as the freeze-thaw cycles were repeated. They revealed that the C30, C40, and C50 air-entrained concrete was still durable after 300 cycles of freeze-thaw according to the experimental results.

  11. Durability of organobentonite-amended liner for decelerating chloroform transport.

    Science.gov (United States)

    He, Shichong; Zhu, Lizhong

    2016-04-01

    Chloroform is added to landfill for suppressing methane generation, which however may transport through landfill liners and lead to contamination of groundwater. To decelerate chloroform transport, the enhanced sorption ability of clay liners following organobentonite addition was tested. In this study, we used batch sorption to evaluate sorption capacity of chloroform to organobentonite, followed by column tests and model simulations for assessing durability of different liners. Results show that adding 10% CTMAB-bentonite (organobentonite synthesized using cetyltrimethylammonium bromide) increased the duration of a bentonite liner by 88.5%. CTMAB-bentonite consistently showed the highest sorption capacity (Qm) among six typical organobentonites under various environmental conditions. The removal rate of chloroform by CTMAB-bentonite was 3.6-23 times higher than that by natural soils. According to the results derived by model simulation, a 70-cm 10% CTMAB-bentonite liner exhibited much better durability than a 100-cm compact clay liner (CCL) and natural bentonite liner evidenced by the delayed and lower peak of eluent concentration. A minimum thickness of 65.8 cm of the 10% CTMAB-bentonite liner could completely sorb the chloroform in a 100-m-high landfill. The 10% CTMAB-bentonite liner exhibiting much better durability has the promise for reducing environmental risk of chloroform in landfill. PMID:26874063

  12. Study on Micro-Structure and Durability of Fiber Concrete

    Directory of Open Access Journals (Sweden)

    Huijun Wu

    2013-01-01

    Full Text Available In this study, we compare micro-structure characteristics of alkali-resistant glass fiber reinforced concrete, polypropylene fiber reinforced concrete, basalt fiber reinforced concrete and common concrete. Moreover, they were tested and analyzed micro-structure characteristics of fiber reinforced concretes by mercury injection, mainly analyzed the size of pore distribution, studied the influence on improving pore structure. In addition, the internal structure of fiber reinforced concrete was researched by scanning electron microscope analysis. Then the influence of fiber on the internal structure was described. Durability of the fiber reinforced concrete was tested. Durability mainly contains the frost-resistance and permeability. The permeability experiment has water-penetration and chloride penetration test study then characterize the permeability of fiber reinforced concrete through the seepage height and chloride ions diffusion coefficient. Through the result of freeze-thaw cycle 100 times we can analyze the frost resistance of fiber reinforced concrete. Finally, some fiber concrete durability is analyzed and compared.

  13. Drowning Prevention

    Science.gov (United States)

    ... Listen Español Text Size Email Print Share Drowning Prevention: Information for Parents Page Content Article Body Drowning ... in very cold water for lengthy periods. Drowning Prevention: Know the Warning Signs These signs may signal ...

  14. Preventing Addiction.

    Science.gov (United States)

    Moore, Susan Fordney

    The purpose of this paper is to provide the beginning counselor with an overview of prevention concepts. Prevention is a relatively new emphasis in community efforts to stem the rising costs of substance abuse and other high-risk behaviors. The paper discusses agent, host, and environmental prevention models and how they relate to causal theories…

  15. Energy and durable development: the place of the renewable energies; Energie et developpement durable: la place des energies renouvelables

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The 29 may 2000, took place at the UNESCO, a colloquium on the place of the renewable energies facing the economic development. This document presents the opening presentation of A. Antolini and L. Jospin and the colloquium papers and debates in the following four domains: the energy challenges of the durable development, the renewable energies sources facing the european directive, the thermal renewable energies (solar, geothermics and biomass) and the greenhouse effect, the world market of the renewable energies. (A.L.B.)

  16. Comparison of durability indicators obtained by Non Destructive Testing methods to monitor the durability of concrete structures

    OpenAIRE

    VILLAIN, Géraldine; Balayssac, Jean-Paul; GARNIER, Vincent; Piwakowski, Bogdan; Salin, Jean; Fardeau, Vincent; Dérobert, Xavier; COFFEC, Odile; Joubert, Anaëlle

    2014-01-01

    This paper deals with the use of non destructive testing methods (NDT) to assess indicators of concrete durability and mechanical properties of reinforced concrete structures. On site, NDT methods based on electromagnetic or ultrasonic wave propagation (such as radar, impact echo, ultrasonic transmission deviceÉ) are used because they are more or less sensitive to water content and mechanical properties depending on the method. It has been shown, in a former project [1, 2], that the NDT resul...

  17. Durability associated efficacy of long-lasting insecticidal nets after five years of household use

    Directory of Open Access Journals (Sweden)

    Msangi Shandala

    2011-08-01

    Full Text Available Abstract Background Long-lasting insecticidal nets (LLINs have been strongly advocated for use to prevent malaria in sub-Saharan Africa and have significantly reduced human-vector contact. PermaNet® 2.0 is among the five LLINs brands which have been given full approval by the WHO Pesticide Evaluation Scheme (WHOPES. The LLINs are expected to protect the malaria endemic communities, but a number of factors within the community can affect their durability and efficacy. This study evaluated the durability, efficacy and retention of PermaNet® 2.0 after five years of use in a Tanzanian community. Method Two to three day- old non blood-fed female mosquitoes from an insectary susceptible colony (An. gambiae s.s, this colony was established at TPRI from Kisumu, Kenya in 1992 and wild mosquito populations (An. arabiensis and Culex quinquefasciatus were used in cone bioassay tests to assess the efficacy of mosquito nets. Findings The knockdown effect was recorded after three minutes of exposure, and mortality was recorded after 24 hours post-exposure. Mortality of An. gambiae s.s from insectary colony was 100% while An. arabiensis and Cx.quinquefasciatus wild populations had reduced mortality. Insecticide content of the new (the bed net of the same brand but never used before and used PermaNet® 2.0 was determined using High Performance Liquid Chromatography (HPLC. Conclusion The results of this study suggest that, in order to achieve maximum protection against malaria, public health education focusing on bed net use and maintenance should be incorporated into the mass distribution of nets in communities.

  18. Polylactic Acid-Based Polymer Blends for Durable Applications

    Science.gov (United States)

    Finniss, Adam

    There has been considerable scientific interest in both research and commercial communities as of late in the area of biologically based or sourced plastics. As the consumption of petroleum rises and concerns about climate change increase, this field is likely to grow even larger. One bioplastic that has received a great deal of attention is polylactic acid (PLA). In the past, this material was used mainly in medical or specialty applications, but advancements in manufacturing have led to a desire to use PLA more widely, especially in durable applications. Unfortunately, PLA has several drawbacks that hinder more widespread usage of the material as a durable item: it has low ductility and impact strength in bulk applications, along with poor stability in the face of heat, humidity or liquid media. To combat these deficiencies, a number of techniques were investigated. Samples were annealed to create crystalline domains that would improve mechanical properties and reduce diffusion, blended with graphene to create barriers to diffusion throughout the material, or compounded with a polycarbonate (PC) polymer phase to protect the PLA phase and to enhance the mechanical properties of the blend. If a material containing biologically sourced components with good mechanical properties can be created, it would be desirable for durable uses such as electronics components or as an automotive grade resin. Crystallization experiments were carried out in a differential scanning calorimeter to determine the effects of heat treatment and additives on the rather slow crystallization kinetics of PLA polymer. It was determined that the blending in of the PC phase did not significantly alter the kinetics or mechanism of crystal growth. The addition of graphene to any PC/PLA formulation served as a nucleating agent which speeded up the crystallization kinetics markedly, in some cases by several orders of magnitude. Results obtained from these experiments were internally consistent

  19. State of the art of durability-performance evaluation of hardened cement based on phase compositions

    International Nuclear Information System (INIS)

    Upgrading durability-performance evaluation technique for concrete is urgently demanded in connection to its application to radio-active waste repository which needs ultra long-term durability. Common concrete structures also require an advanced method for minimizing the life-cycle cost. The purpose of this research is to investigate current problems and future tasks on durability-performance evaluation of hardened cement from the view point of phase composition. Although the phase composition of hardened cement has not fully been reflected to durability-performance evaluation, it influences concrete durability as well as its pore structure. This report reviews state of the art of the factors affecting phase composition, analytical and experimental evaluation techniques for phase composition, and durability-performance evaluation methods of hardened cement based on phase composition. (author)

  20. Evaluation of the Mechanical Durability of the Egyptian Machine Readable Booklet Passport

    Directory of Open Access Journals (Sweden)

    Ahmed Mahmoud Yosri

    2013-12-01

    Full Text Available In 2008 the first Egyptian booklet Machine Readable Passport/ MRP has been issued and its security and informative standard quality levels were proved in a research published in 2011. Here the durability profiles of the Egyptian MRP have been evaluated. Seven mechanical durability tests were applied on the Egyptian MRP. Such tests are specified in the International Civil Aviation Organization / ICAO standard requirements documents. These seven very severe durability tests resulted in that the Egyptian MRP has achieved better & higher results than the values detected in ICAO-Doc N0232: Durability of Machine Readable Passports - Version: 3.2. Hence, this research had proved the complete conformance between the Egyptian MRP mechanical durability profiles to the international requirements. The Egyptian booklet MRP doesn’t need any obligatory modification concerning its mechanical durability profiles.

  1. Forecasting of durability of waterborne coatings in the machine industry

    Directory of Open Access Journals (Sweden)

    K. Lenik

    2009-06-01

    Full Text Available Purpose: The paper presents the problems of forecasting of durability of waterborne acrylic coatings and epoxy coatings designed to protect devices and machine elements.Design/methodology/approach: The durability forecast has been performed on the basis of analyses of time series with the use of trend function extrapolation. Mechanical properties such as: scratch resistance, impact strength, grindability and luster have also been evaluated. Moreover, besides standardized methods, some complementary methods have been applied in the form of analyses of microscopic images of damage caused by the exposition of coatings to corrosion.Findings: Assuming five-year durability for coatings on devices and machine elements (time between overhauls, one can find that investigated waterborne coatings can be a successful protection of devices and machine elements in the established range and in the dependence on the applied system.Research limitations/implications: The research has shown some substantial influence of coating system width changes on obtained results of scratch resistance and impact strength. It should be beneficial to extend further research with the description of the mechanism that enables to obtain some strict correlation between the investigated properties of coatings and the allowance of their width.Practical implications: The research makes possible to determine the areas of application for coatings obtained from waterborne materials to anticorrosion protection of devices and machine elements. This enables to eliminate gradually traditional solvent coatings (of high VOC content, which are disadvantageous to the environment.Originality/value: The applied sequence of research can form a proposal of the method to evaluate coatings made of some other than investigated waterborne materials predestinated for machine industry.

  2. Direct alcohol fuel cells materials, performance, durability and applications

    CERN Document Server

    Corti, Horacio R

    2013-01-01

    Direct Alcohol Fuel Cells: Materials, Performance, Durability and Applications begins with an introductory overview of direct alcohol fuel cells (DAFC); it focuses on the main goals and challenges in the areas of materials development, performance, and commercialization. The preparation and the properties of the anodic catalysts used for the oxidation of methanol, higher alcohols, and alcohol tolerant cathodes are then described. The membranes used as proton conductors in DAFC are examined, as well as alkaline membranes, focusing on the electrical conductivity and alcohol permeability. The use

  3. PEM Fuel Cell Freeze Durability and Cold Start Project

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, T.; O' Neill, Jonathan

    2008-01-02

    UTC has taken advantage of the unique water management opportunities inherent in micro-porous bipolar-plates to improve the cold-start performance of its polymer electrolyte fuel cells (PEFC). Diagnostic experiments were used to determine the limiting factors in micro-porous plate PEFC freeze performance and the causes of any performance decay. Alternative cell materials were evaluated for their freeze performance. Freeze-thaw cycling was also performed to determine micro-porous plate PEFC survivability. Data from these experiments has formed the basis for continuing development of advanced materials capable of supporting DOE's cold-start and durability objectives.

  4. NOTE: Deformable and durable phantoms with controlled density of scatterers

    Science.gov (United States)

    Bisaillon, Charles-Etienne; Lamouche, Guy; Maciejko, Romain; Dufour, Marc; Monchalin, Jean-Pierre

    2008-07-01

    We have developed deformable and durable optical tissue phantoms with a simple and well-defined microstructure including a novel combination of scatterers and a matrix material. These were developed for speckle and elastography investigations in optical coherence tomography, but should prove useful in many other fields. We present in detail the fabrication process which involves embedding silica microspheres in a silicone matrix. We also characterize the resulting phantoms with scanning electron microscopy and optical measurements. To our knowledge, no such phantoms were proposed in the literature before. Our technique has a wide range of applicability and could also be adapted to fabricate phantoms with various optical and mechanical properties.

  5. Water-thinnable polymers for durable coatings for different materials

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, Piotr, E-mail: piotr.jankowski@ichp.pl; Kijowska, Dorota, E-mail: piotr.jankowski@ichp.pl [Industrial Chemistry Research Institute, Department of Polyesters, Epoxides and Polyurethanes, 8 Rydygiera Str., 01-793 Warszawa (Poland)

    2014-05-15

    The methods of obtaining water-thinnable polymers - water-thinnable unsaturated polyester resins (WTUPR) - by polycondensation were elaborate and optimized. As hydrophilic monomers different types of sulfonate monomers were used. The monomers, with sulfonate groups and other reactive groups, were obtained by sulfonation of organic compounds with satisfactory yield. All products were analyzed by {sup 1}H NMR and {sup 13}C NMR spectra. WTUPR were used as polymeric binders for coatings applications. Coatings with relatively high pendulum hardness, good properties and durability, useful for practical applications, were obtained. Typical existing equipment for the production of unsaturated polyester resins can be applied for the industrial preparation of WTUPR.

  6. Highly-Durable Carbon Electrode for Electrochemical Capacitors

    Directory of Open Access Journals (Sweden)

    Soshi Shiraishi

    2013-01-01

    Full Text Available The electric double layer capacitor (EDLC is anelectrochemical capacitor storing electric energy bycharging the electric double layer on the microporesof a nanoporous carbon electrode such as activatedcarbon. The EDLC has a fast charge-dischargeproperty and excellent cycle life, but its energydensity is lower than other electrochemical energystorage devices such as the rechargeable battery.The energy density of the EDLC can be improvedby increasing the double layer capacitance and themaximum charging voltage. In this review, the authordescribes the activated carbon electrodes for use ina durable EDLC for high voltage charging.

  7. Properties of Leakage Corrosion of Concrete and Its Durability

    Institute of Scientific and Technical Information of China (English)

    GE Xueliang; FANG Kunhe; ZENG Li; CHEN Xia

    2008-01-01

    The properties and mechanism of concrete under water leakage corrosion were studied in terms of the dissolution of calcium oxide and silicon oxide from concrete and the variation of pH value of permeate water.The experimental results show that the amount of calcium oxide and silicon oxide dissolved from per cubic meter of concrete gradually decrease with penetration time and ultimately stabilize at a certain value.The pH value of permeate water descend along with penetration time.The durability of concrete under leakage corrosion was analyzed by a formula fitted on the dissolved amount of calcium oxide.

  8. Methods for Using Durable Adhesively Bonded Joints for Sandwich Structures

    Science.gov (United States)

    Smeltzer, Stanley S., III (Inventor); Lundgren, Eric C. (Inventor)

    2016-01-01

    Systems, methods, and apparatus for increasing durability of adhesively bonded joints in a sandwich structure. Such systems, methods, and apparatus includes an first face sheet and an second face sheet as well as an insert structure, the insert structure having a first insert face sheet, a second insert face sheet, and an insert core material. In addition, sandwich core material is arranged between the first face sheet and the second face sheet. A primary bondline may be coupled to the face sheet(s) and the splice. Further, systems, methods, and apparatus of the present disclosure advantageously reduce the load, provide a redundant path, reduce structural fatigue, and/or increase fatigue life.

  9. Durable innovative solar optical materials: the international challenge

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, C.M.

    1982-01-01

    A variety of optical coatings are discussed in the context of solar energy utilization. Well known coatings such as heat mirrors, selective absorbers, and reflective films are covered briefly. Emphasis is placed on the materials limitations and design choices for various lesser known optical coatings and materials. Physical and optical properties are detailed for protective antireflection films, fluorescent concentrator materials, holographic films, cold mirrors, radiative cooling surfaces, and optical switching films including electrochromic, thermochromic, photochromic, and liquid crystal types. For many of these materials research is only now being considered, and various design and durability issues must be addressed.

  10. Durable, Low-cost, Improved Fuel Cell Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Chris Roger; David Mountz; Wensheng He; Tao Zhang

    2011-03-17

    The development of low cost, durable membranes and membranes electrode assemblies (MEAs) that operate under reduced relative humidity (RH) conditions remain a critical challenge for the successful introduction of fuel cells into mass markets. It was the goal of the team lead by Arkema, Inc. to address these shortages. Thus, this project addresses the following technical barriers from the fuel cells section of the Hydrogen Fuel Cells and Infrastructure Technologies Program Multi-Year Research, Development and Demonstration Plan: (A) Durability (B) Cost Arkema’s approach consisted of using blends of polyvinylidenefluoride (PVDF) and proprietary sulfonated polyelectrolytes. In the traditional approach to polyelectrolytes for proton exchange membranes (PEM), all the required properties are “packaged” in one macromolecule. The properties of interest include proton conductivity, mechanical properties, durability, and water/gas transport. This is the case, for example, for perfluorosulfonic acid-containing (PFSA) membranes. However, the cost of these materials is high, largely due to the complexity and the number of steps involved in their synthesis. In addition, they suffer other shortcomings such as mediocre mechanical properties and insufficient durability for some applications. The strength and originality of Arkema’s approach lies in the decoupling of ion conductivity from the other requirements. Kynar® PVDF provides an exceptional combination of properties that make it ideally suited for a membrane matrix (Kynar® is a registered trademark of Arkema Inc.). It exhibits outstanding chemical resistance in highly oxidative and acidic environments. In work with a prior grant, a membrane known as M41 was developed by Arkema. M41 had many of the properties needed for a high performance PEM, but had a significant deficiency in conductivity at low RH. In the first phase of this work, the processing parameters of M41 were explored as a means to increase its proton

  11. Durability Analysis of Subway Station in Chloride Environment

    Directory of Open Access Journals (Sweden)

    Yang LuFeng

    2013-02-01

    Full Text Available In this study, a finite element model for chloride ions transport in saturated concrete was proposed based on the Fick’s second law of diffusion. The governing partial differential equation was solved numerically in space as a boundary-value problem and in time as an initial-value problem by means of the finite element formulations. The maximum allowable value of chloride diffusion coefficient within different locations of subway station with service life of 100a was achieved and suggestions for durability analysis of subway station in chloride environment were also proposed.

  12. Experimental investigation of the variability of concrete durability properties

    International Nuclear Information System (INIS)

    One of the main objectives of the APPLET project was to quantify the variability of concrete properties to allow for a probabilistic performance-based approach regarding the service lifetime prediction of concrete structures. The characterization of concrete variability was the subject of an experimental program which included a significant number of tests allowing the characterization of durability indicators or performance tests. Two construction sites were selected from which concrete specimens were periodically taken and tested by the different project partners. The obtained results (mechanical behavior, chloride migration, accelerated carbonation, gas permeability, desorption isotherms, porosity) are discussed and a statistical analysis was performed to characterize these results through appropriate probability density functions. (authors)

  13. SEM investigation of incandescent lamp mantle structure on durability

    International Nuclear Information System (INIS)

    Full text: The incandescent mantle as used on pressure and non-pressure liquid fuel lamps has been in use for over 100 years. What remains unexplained is the way in which the resistance to mechanical shock and the decline in tensile strength with usage is experienced. It has been suggested that to improve durability it is necessary to continuously burn a new mantle for the first two to three hours. The known factors in mantle durability and mechanical strength are chemical composition and fabric weave. This study was undertaken to investigate the effects of burning time and temperature on thorium oxide mantles. The operating temperature of mantles on a range of kerosene pressure lamps was measured and found to be between 800 and 1100 deg C. Heat treatments of thorium based Coleman mantles were carried out in a laboratory furnace within these ranges of temperatures for periods ranging from 2 minutes to 2 hours. The mantles were then viewed in a LEO S440 analytical SEM. Results at 800 deg C show a distinct change in surface morphology with increasing exposure time. At the shorter times (2-5 minutes) the surface was relatively smooth. With increased time periods (15 - 120 minutes) the surface was observed to have a large lumpy structure. At 1100 deg C the difference in surface morphology was not apparent between the shortest and longest times. The surface appears much smoother and no lumpy structure was observed. This suggests that when a mantle is operated at the higher temperature of 1100 deg C the structure of the Thorium oxide is quickly transformed into the known stronger amorphous form. This is taken as the observed smooth structure seen in the SEM images of the 1100 deg C samples. Thus the mantle is expected to be more resistant to mechanical shock and have increased durability. Practical field test results confirm these observations. The mantle on a lamp that is operating efficiently, burns brightly, will far outlast a mantle on an inefficient lamp which bums

  14. Durability of cracked fibre reinforced concrete structures exposed to chlorides

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Ekman, Tom; Hansen, Kurt Kielsgaard

    Durability studies are carried out by subjecting FRC-beams to combined mechanical and environmental load. Mechanical load is obtained by exposing beams to 4-point bending until a predefined crack width is reached, using a newly developed test setup. Exposure to a concentrated chloride solution is...... used as environmental load. The chloride penetration is characterized both qualitatively (UV-test) and quantitatively (chloride profile) and by microscopy. The test programme involves three different concrete qualities. Both steel fibres and polypropylene fibres are used in the concrete beams as well...... as main reinforcement. The effect of the cracks, the fibres and the concrete quality on the chloride penetration is studied....

  15. Durability of Polymeric Encapsulation Materials for Concentrating Photovoltaic Systems (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D. C.; Kempe, M. D.; Araki, K.; Kennedy, C. E.; Kurtz, S. R.

    2011-02-01

    Polymeric encapsulation materials are typically used in concentrating photovoltaic (CPV) modules to protect the cell from the field environment. Because it is physically located adjacent to the cell, the encapsulation is exposed to a high optical flux, often including light in the ultraviolet (UV) and infrared (IR) wavelengths. The durability of encapsulants used in CPV modules is critical to the technology, but is presently not well understood. This work seeks to identify the appropriate material types, field-induced failure mechanisms, and factors of influence (if possible) of polymeric encapsulation. These results will ultimately be weighed against those of future qualification and accelerated life test procedures.

  16. High temperature steam electrolysis stack with enhanced performance and durability

    International Nuclear Information System (INIS)

    High Temperature Steam Electrolysis (HTSE) is one of the most promising ways for hydrogen production. If coupled to a CO2-free electricity and low cost heat sources, this process is liable to a high efficiency. The present study describes recent promising results obtained in terms of performance and durability in stack environment, thanks to the use of protective coatings on one hand, and of advanced cells on the other hand. As for Solid Oxide Fuel Cells, it has been demonstrated that the integration of protective coatings was mandatory to decrease the degradation rate in HTSE stacks, and that with optimized coatings, (CoMn)3O4 in the present case, the same durability as the one of the single cell tested in a ceramic housing could be reached. The type of cell was also shown to play a major role on the degradation rate. With advanced cells, degradations below 2%/kh could be reached. The higher is the current density, the higher is the degradation rate, with a mostly reversible effect. These degradation rates are close to the objectives, even if a bit higher than in SOFC mode. Finally a low-weight stack has been designed, targeting high performance and durability while reducing the cost by the use of thin interconnects. An electrochemical performance similar to the previous stack design has been obtained for a 3-cell stack (-1 A/cm2) at 1.3 V at 800 degrees C), with degradation rates below 3%/1000 h in the testing conditions. The thermal cyclability of stacks has been demonstrated, from 800 degrees C to 20 degrees C, as well as electrical load cycling. The results showed that the HTSE stacks considered in the present study can cycle very rapidly, and that the cycles considered do not induce any degradation. Therefore it can be concluded that these results makes HTSE technology getting closer to the objectives of performance, durability, thermal and electrical cyclability and cost, and that HTSE is a candidate to produce hydrogen as a mean to store renewable

  17. Water-thinnable polymers for durable coatings for different materials

    Science.gov (United States)

    Jankowski, Piotr; Kijowska, Dorota

    2014-05-01

    The methods of obtaining water-thinnable polymers - water-thinnable unsaturated polyester resins (WTUPR) - by polycondensation were elaborate and optimized. As hydrophilic monomers different types of sulfonate monomers were used. The monomers, with sulfonate groups and other reactive groups, were obtained by sulfonation of organic compounds with satisfactory yield. All products were analyzed by 1H NMR and 13C NMR spectra. WTUPR were used as polymeric binders for coatings applications. Coatings with relatively high pendulum hardness, good properties and durability, useful for practical applications, were obtained. Typical existing equipment for the production of unsaturated polyester resins can be applied for the industrial preparation of WTUPR.

  18. Chemically durable phosphate glasses and a method for their preparation

    Science.gov (United States)

    Day, D.E.; Wilder, J.A. Jr.

    The chemical durability of alkali phosphate glasses is improved by incorporation of up to 23 weight percent of nitrogen. A typical phosphate glass contains: 10 to 60 mole % of Li/sub 2/O, Na/sub 2/O or K/sub 2/O; 5 to 40 mole % of BaO or CaO; 0 to 1 to 10 mole % of Al/sub 2/O/sub 3/; and 40 to 70 mole % of P/sub 2/O/sub 5/. Nitrides, such as AlN, are the favored additives.

  19. Flexible, durable proton energy degraders for the GE PETtrace

    DEFF Research Database (Denmark)

    Engle, J. W.; Gagnon, K.; Severin, Gregory;

    2012-01-01

    In order to limit the formation of radioisotopic impurities during proton bombardments of solid targets, two methods of introducing degrader foils into the beam upstream of the target were tested. The first design uses a 445 μm thick fixed degrader machined from a single piece of aluminum. The...... second design permits introduction of foils made of any material and was tested with foils as thick as 635 μm (also aluminium). In both cases, the foils are cooled with by water flowing through an annular channel outside the radius of the beam. Both designs proved durable and tolerated proton beam...

  20. PREDICTING THE DURABILITY OF EXTRUDED FOAM POLYSTYRENE IN ROAD STRUCTURES

    Directory of Open Access Journals (Sweden)

    V. P. Yartsev

    Full Text Available Statement of the problem. It is possible to improve working conditions of road pavement and to use it more efficiently by regulating water-thermal conditions of the subgrade thereby reducing humidity in the design period and mitigating its seasonal changes.Results and conclusions. It is suggested to use extruded foam polystyrene as a heating layer. The thermal fluctuation approach was applied to failure and deformation processes. Physical constants for the analytical description of these processes at varying temperatures and stresses are calculated. The technique for determining acting stresses and temperatures was described. The prediction of the durability of extruded foam polystyrene in road structure is presented

  1. Towards an european strategy of safe and durable energy supply

    International Nuclear Information System (INIS)

    This paper is a copy of the speech of L. de Palacio, vice-president of the european commission, in charge of the energy and the transports, concerning the european strategy of safe and durable energy supplying. The author analyses the today and future situations and emphasizes on the european responsibility and the world prejudice. The petroleum supply dependence in thirty years and the environment policy lead to a diversification of the energy sources and a better international cooperation with the producers countries. (A.L.B.)

  2. Local spillovers and learning from neighbors: Evidence from durable adoptions in rural China

    OpenAIRE

    Feng, Yao

    2011-01-01

    Using the 1999 durable consumption survey data in rural China, we examine the importance of local spillovers in the diffusion of three major durable goods, i.e., color television set, washing machine, and refrigerator. We find that, with control for many family characteristics, a household is more likely to buy its first durable good in villages where a large share of households already own one. Further evidence suggests that theses patterns are unlikely to be explained by unobserved local ch...

  3. Sensoric assessment of the durable meat product depending on the production technology.

    OpenAIRE

    TÁBOR, Rudolf

    2011-01-01

    This diploma thesis deals with sensoric analysis of the selected types of durable meat products depending on the production technology. By sensoric assessment and subsequent statistic analysis, this diploma thesis pursues to compare fermented durable meat products, made without added starting cultures, with fermented durable meat products, made with added starting cultures, and to determine which of these kinds of products are preferred by the evaluators as well as the consumers. The theoreti...

  4. Durability Assessment of Concrete Structures in HZM Sea Link Project for Design Life of 120 Years

    OpenAIRE

    Li, Kefei; Li, Q. W.; Zhang, Q M; Fan, Z. H.; Yang, L. H.

    2014-01-01

    This article presents the durability assessment of the concrete structures in the ongoing Hong Kong–Zhuhai–Macao (HZM) sea link project for a design service life of 120 years. During the preliminary study phase, the durability design of concrete structures has been performed by a model-based method with a partial factor scheme for chloride-induced corrosion process. On the basis of the actual design options adopted in the detailed design phase, the durability assessment of concrete structures...

  5. Are Consumers Affected by Durable Goods Makers' Financial Distress? The Case of Auto Manufacturers

    OpenAIRE

    Ali Hortaçsu; Gregor Matvos; Chad Syverson; Sriram Venkataraman

    2010-01-01

    The financial decisions of durable goods makers can impose spillovers on their consumers. Namely, durable goods provide a consumption stream that frequently depends on services provided by the manufacturer (e.g., warranties, parts, and maintenance). Manufacturer bankruptcy, or even the possibility thereof, threatens this service provision and can substantially reduce the value of its products to their current owners. We test this hypothesis in one of the largest durable goods markets, automob...

  6. Durable, High Thermal Conductivity Melt Infiltrated Ceramic Composites for Turbine Engine Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Durable, creep-resistant ceramic composites are necessary to meet the increased operating temperatures targeted for advanced turbine engines. Higher operating...

  7. Tube Hydroforming Process Designe of Torsion Beam Type Rear Suspension Considering Durability

    Science.gov (United States)

    Lee, Kyung-Taek; Back, Hong-Juen; Lim, Hee-Taek; Oh, In-Suk; Kim, Heon-Young

    Manufacturing processes for automobile suspension components have generally considered the formability but not the durability of the suspension system, even though the latter is very important in the dynamic performance of the vehicle. Suspension systems should be designed with both formability and durability in mind. This paper describes the design of an optimal forming process to control the cross-sectional properties of the torsion beam in rear suspension systems for increased roll durability. Stamping and hydroforming simulations were performed using the finite element method to determine the optimum tube hydroforming process for producing a torsion beam with the best roll durability performance.

  8. Poison Prevention

    Science.gov (United States)

    ... Prevention Listen Español Text Size Email Print Share Poison Prevention Page Content Article Body Post the Poison Help number 1-800-222-1222 on the ... or empty container of a toxic substance, call Poison Help immediately. More than a million American children ...

  9. Preventing Suicide

    Science.gov (United States)

    ... Center for Injury Prevention and Control, Division of Violence Prevention Page maintained by: Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs Email Recommend Tweet YouTube Instagram Listen Watch RSS ABOUT About CDC Jobs ...

  10. Preventing Falls

    Science.gov (United States)

    ... from osteoporosis. Lower-body strength exercises and balance exercises can help you prevent falls and avoid the disability that may result from falling. Here are some fall prevention tips from Go4Life : l Have your eyes and hearing tested often. Always wear your glasses when you ...

  11. Preventative Maintenance.

    Science.gov (United States)

    Migliorino, James

    Boards of education must be convinced that spending money up front for preventive maintenance will, in the long run, save districts' tax dollars. A good program of preventive maintenance can minimize disruption of service; reduce repair costs, energy consumption, and overtime; improve labor productivity and system equipment reliability; handle…

  12. NATURAL DURABILITY AND PHENOLIC CONTENT IN DRIED SCOTS PINE HEARTWOOD

    Directory of Open Access Journals (Sweden)

    Margot Sehlstedt-Persson

    2010-04-01

    Full Text Available The durability of Scots pine heartwood has previously been shown to be affected by the industrial drying process of sawn lumber. The durability of heartwood from boards dried at temperatures between 20°C-110°C was studied by measuring the mass loss in a decay test with a brown rot fungus (Coniophora puteana, and the concentration of total phenolics was measured according to the Folin-Ciocalteu (FC assay. The relation between mass loss and phenolics in dried heartwood showed a weaker negative correlation at lower levels of phenolics as compared to the strong relationship found in a study on heartwood from standing Scots pine trees. Mass loss in dried heartwood showed a weak negative correlation to density. Heating of extractives-rich green sawdust under moist conditions resulted in a reduction of phenolics with temperature up to 180 oC and with increasing time. The concentration of phenolics in heated, green sawdust was higher in extractives-rich pine heartwood than in heartwood with a normal extractives content.

  13. Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Ganesan Lavanya

    2015-01-01

    Full Text Available This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were 150×150×150 mm cubes, 100×200 mm cylinders, and 100×50 mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.

  14. NATURAL DURABILITY OF THREE WOOD SPECIES IN FIELD TESTS

    Directory of Open Access Journals (Sweden)

    Rafael Rodolfo de Melo

    2010-08-01

    Full Text Available This work aimed to evaluate the natural durability of heartwood and sapwood of Luhea divaricata, Carya illinoinensis and Platanus x acerifolia. Test samples measuring 2.5 x 2.5 x 30.0 cm (radial x tangential x longitudinal were placed in a pine forest stand and an open field. During a year, the samples were repeatedly weighed and evaluated by a rating system to determine mass loss and decay index, respectively. The results showed that regardless of species and type of wood, the forest environment is more favourable to decay than that of the open field. Despite the high correlation between mass loss and decay index, variations in the durability of wood were found between these parameters. The wood from the internal section of the log (sapwood was the more affected. For mass loss, no significant variation was observed for the species analyzed, however, for the decay index Platanus x acerifolia was shown to be the most affected.

  15. Towards a durable management of genetic resistances to Leptosphaeria maculans

    Directory of Open Access Journals (Sweden)

    Pinochet Xavier

    2003-05-01

    Full Text Available Blackeg is the major disease of winter oilseed rape in France. For an efficient control of the disease several tools could be combined, but mainly plant breeding has been used to increase winter oilseed rape resistance to blackleg. A useful step was reached in the nineties, using a specific resistance gene (Rlm1. After being widely used this resistance was broken down by an increase of the virulent sub-populations of the fungus. Such a situation worried the different actors and raised the question of the promotion of a durable management of genetic resistances to Leptosphaeria. After a synthetic presentation of the state of the art in the fields of genetics of resistance, of Leptosphaeria populations and on agronomic practices able to control the pathogen, the promotion of a durable management of resistances is discussed. This target needs to precise the strategy, to improve methodologies to characterise genotypes, to promote proper agronomic practices, to follow Leptosphaeria population behaviour and to motivate economic actors.

  16. Neural network analysis of nuclear waste glass composition vs durability

    International Nuclear Information System (INIS)

    The relationship between the chemical composition of oxide glasses and their physical properties is poorly understood, but it is becoming more important as vitrification (transformation into glass) of high-level nuclear waste becomes the favored method for long-term storage. The vitrified waste will be stored deep in geologic repositories where it must remain intact for at least 10,000 years. A strong resistance to groundwater exposure; i.c. a slow rate of glass dissolution, is of great importance. This project deals specifically with glass samples developed and tested for the nuclear fuel reprocessing facility near West Valley, New York. This facility needs to dispose of approximately 2.2 million liters of high-level radioactive liquid waste currently stored in stainless steel tanks. A self-organizing, artificial neural network was used to analyze the trends in the glass dissolution data for the effects of composition and the resulting durability of borosilicate glasses in an aqueous environment. This durability data can be used to systematically optimize the properties of the complex nuclear glasses and slow the dissolution rate of radionuclides into the environment

  17. Tungsten materials as durable catalyst supports for fuel cell electrodes

    Science.gov (United States)

    Perchthaler, M.; Ossiander, T.; Juhart, V.; Mitzel, J.; Heinzl, C.; Scheu, C.; Hacker, V.

    2013-12-01

    Durable platinum catalyst support materials, e.g. tungsten carbide (WC), tungsten oxide (WOx) and self-synthesized tungsten oxide (WOxs) were evaluated for the use in High-Temperature Proton Exchange Fuel Cells (HT-PEM) based on phosphoric acid doped polybenzimidazole as electrolyte. The support materials and the catalyst loaded support materials were characterized ex-situ by cyclic voltammetry in HClO4, potential cycling, CO-stripping, electron microscopy and X-ray diffraction measurements. The tungsten oxide and tungsten carbide based supported catalysts were compared to High Surface Area Carbon (HSAC), each coated with platinum via the same in-house manufacturing procedures. The in-house manufacturing procedures resulted in catalyst particle sizes on HSAC of 3-4 nm with a uniform distribution. The in-situ Potential Cycling experiments of WOx or WOxs supported catalysts showed much lower degradation rates compared to High Surface Area Carbons. The formation of WOx species on WC was proven by ex- and in-situ cyclic voltammetric studies and thermogravimetric analyses. X-ray diffraction, ex-situ cyclic voltammetry and in-situ cyclic voltammetry showed that WOx is formed from WC as starting material under oxidizing conditions. Finally a 1000 h durability test with WOx as catalyst support material on the anode was done in a HT-PEM fuel cell with reformed methanol on the anode.

  18. Durable concrete for a waste repository - Measurement of ionic ingress

    International Nuclear Information System (INIS)

    A waste repository for the below ground disposal of low level radioactive waste is planned at Chalk River Nuclear Laboratories. It relies greatly on the durability of concrete for the required 500 year service life. A research program to design durable concrete and predict its service life is in progress. The degradation of the concrete depends to a large extent on the rate of ingress of corrosive agents. Penetration of chloride and sulfate ions are particularly relevant. Twenty mix formulations were developed to create various types and qualities of concrete, and to study their behavior in different site environmental conditions. A total of 1,000 concrete specimens are being exposed at 20C and 45C to 25 different combinations of the corrosive agents including CO2. Procedures to measure the ionic profiles and to determine the factors controlling diffusion of the ions in the various concretes have been developed. Results of selected concrete systems exposed to chloride and sulfate solutions for 1 year are presented and discussed in terms of pore structure and permeability parameters of the concrete

  19. Enhanced durability of desulfurization sorbents for fluidized-bed applications

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, R.P.; Gangwal, S.K.

    1991-06-01

    Advanced integrated gasification combined cycle (IGCC) power systems require the development of high-temperature desulfurization sorbents capable of removing hydrogen sulfide from coal gasifier down to very low levels. The objective of this investigation was to identify and demonstrate methods for enhancing the long-term chemical reactivity and mechanical strength of zinc ferrite, a leading regenerable sorbent, for fluidized-bed applications. Fluidized sorbent beds offer significant potential in IGCC systems because of their ability to control the highly exothermic regeneration involved. However, fluidized beds require a durable, attrition-resistant sorbent in the 100--300 {mu}m size range. A bench-scale high-temperature, high- pressure (HTHP) fluidized-bed reactor (7.6-cm I.D.) system capable of operating up to 24 atm and 800{degree}C was designed, built and tested. A total of 175 sulfidation-regeneration cycles were carried out using KRW-type coal gas with various zinc ferrite formulations. A number of sorbent manufacturing techniques including spray drying, impregnation, crushing and screening, and granulation were investigated. While fluidizable sorbents prepared by crushing durable pellets and screening had acceptable sulfur capacity, they underwent excessive attrition during multicycle testing. The sorbent formulations prepared by a proprietary technique were found to have excellent attrition resistance and acceptable chemical reactivity during multicycle testing. However, zinc ferrite was found to be limited to 550{degree}C, beyond which excessive sorbent weakening due to chemical transformations, e.g., iron oxide reduction, was observed.

  20. Durable superhydrophobic carbon soot coatings for sensor applications

    Science.gov (United States)

    Esmeryan, K. D.; Radeva, E. I.; Avramov, I. D.

    2016-01-01

    A novel approach for the fabrication of durable superhydrophobic (SH) carbon soot coatings used in quartz crystal microbalance (QCM) based gas or liquid sensors is reported. The method uses modification of the carbon soot through polymerization of hexamethyldisiloxane (HMDSO) by means of glow discharge RF plasma. The surface characterization shows a fractal-like network of carbon nanoparticles with diameter of ~50 nm. These particles form islands and cavities in the nanometer range, between which the plasma polymerized hexamethyldisiloxane (PPHMDSO) embeds and binds to the carbon chains and QCM surface. Such modified surface structure retains the hydrophobic nature of the soot and enhances its robustness upon water droplet interactions. Moreover, it significantly reduces the insertion loss and dynamic resistance of the QCM compared to the commonly used carbon soot/epoxy resin approach. Furthermore, the PPHMDSO/carbon soot coating demonstrates durability and no aging after more than 40 probing cycles in water based liquid environments. In addition, the surface layer keeps its superhydrophobicity even upon thermal annealing up to 540 °C. These experiments reveal an opportunity for the development of soot based SH QCMs with improved electrical characteristics, as required for high-resolution gas or liquid measurements.

  1. Durability of cement stabilized low-level wastes

    International Nuclear Information System (INIS)

    Cementitious materials containing high proportions of slag and fly ash have been tested for suitability to immobilize simulated alkaline and carbonated off-gas waste solutions after vitrification of low- level tank wastes stored at Hanford. To assess their performance, long-term durability was assessed by measuring stability of compressive strength and weight during leaching and exposure to sulfate and carbonate solutions. The important parameter controlling the durability is pore structure, because it affects both compressive strength and susceptibility to different kinds of chemical attack. Impedance spectroscopy was utilized to assess the connectivity of the pore system at early ages. Mercury intrusion porosimetry (MIP) and SEM were utilized to assess development of porosity at later ages. Phase alterations in the matrix exposed to aging and leaching in different media were followed using XRD. Mixtures were resistant to deterioration during immersion in solutions containing high concentrations of sulfate or carbonate ions. Mixtures were also resistant to leaching. These results are consistent with microstructural observations, which showed development of a finer pore structure and reduction in diffusivity over days or months of hydration

  2. Fatigue behaviour analysis for the durability prequalification of strengthening mortars

    International Nuclear Information System (INIS)

    An innovative laboratory procedure used as a preliminary design stage for the pre-qualification of strengthening mortars applied to historical masonry buildings is described. In the analysis of the behaviour of masonry structures and their constituent materials, increasing importance has been assumed by the study of the long-term evolution of deformation and mechanical characteristics, which may be affected by both loading and environmental conditions. Through static and fatigue tests on mixed specimens historical brick-reinforced mortar it has been possible to investigate the durability of strengthening materials, in order to select, from a range of alternatives, the most suitable for the historical masonry. Cyclic fatigue stress has been applied to accelerate the static creep and to forecast the corresponding creep behaviour of the historical brick-strengthening mortar system under static long-time loading. This methodology has proved useful in avoiding the errors associated with materials that are not mechanically compatible and guarantees the durability of strengthening work. The experimental procedure has been used effectively in the biggest restoration building site in Europe, the Royal Palace of Venaria, and it is in progress of carrying out at the Special Natural Reserve of the Sacro Monte di Varallo, in Piedmont (Italy).

  3. Durability of conventional concretes containing black rice husk ash.

    Science.gov (United States)

    Chatveera, B; Lertwattanaruk, P

    2011-01-01

    In this study, black rice husk ash (BRHA) from a rice mill in Thailand was ground and used as a partial cement replacement. The durability of conventional concretes with high water-binder ratios was investigated including drying shrinkage, autogenous shrinkage, depth of carbonation, and weight loss of concretes exposed to hydrochloric (HCl) and sulfuric (H(2)SO(4)) acid attacks. Two different replacement percentages of cement by BRHA, 20% and 40%, and three different water-binder ratios (0.6, 0.7 and 0.8) were used. The ratios of paste volume to void content of the compacted aggregate (γ) were 1.2, 1.4, and 1.6. As a result, when increasing the percentage replacement of BRHA, the drying shrinkage and depth of carbonation reaction of concretes increased. However, the BRHA provides a positive effect on the autogenous shrinkage and weight loss of concretes exposed to hydrochloric and sulfuric acid attacks. In addition, the resistance to acid attack was directly varied with the (SiO(2) + Al(2)O(3) + Fe(2)O(3))/CaO ratio. Results show that ground BRHA can be applied as a pozzolanic material and also improve the durability of concrete. PMID:20863608

  4. Final Report - MEA and Stack Durability for PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Yandrasits, Michael A.

    2008-02-15

    Proton exchange membrane fuel cells are expected to change the landscape of power generation over the next ten years. For this to be realized one of the most significant challenges to be met for stationary systems is lifetime, where 40,000 hours of operation with less than 10% decay is desired. This project conducted fundamental studies on the durability of membrane electrode assemblies (MEAs) and fuel cell stack systems with the expectation that knowledge gained from this project will be applied toward the design and manufacture of MEAs and stack systems to meet DOE’s 2010 stationary fuel cell stack systems targets. The focus of this project was PEM fuel cell durability – understanding the issues that limit MEA and fuel cell system lifetime, developing mitigation strategies to address the lifetime issues and demonstration of the effectiveness of the mitigation strategies by system testing. To that end, several discoveries were made that contributed to the fundamental understanding of MEA degradation mechanisms. (1) The classically held belief that membrane degradation is solely due to end-group “unzipping” is incorrect; there are other functional groups present in the ionomer that are susceptible to chemical attack. (2) The rate of membrane degradation can be greatly slowed or possibly eliminated through the use of additives that scavenge peroxide or peroxyl radicals. (3) Characterization of GDL using dry gases is incorrect due to the fact that fuel cells operate utilizing humidified gases. The proper characterization method involves using wet gas streams and measuring capillary pressure as demonstrated in this project. (4) Not all Platinum on carbon catalysts are created equally – the major factor impacting catalyst durability is the type of carbon used as the support. (5) System operating conditions have a significant impact of lifetime – the lifetime was increased by an order of magnitude by changing the load profile while all other variables remain

  5. Information report brought in according to article 145 of the rule by the mission of information on shale gas and oil on the behalf of Sustainable Development and Land Planning Commission; Rapport d'information depose en application de l'article 145 du reglement par la mission d'information sur les gaz et huile de schiste au nom de la Commission du Developpement Durable et de l'Amenagement du Territoire

    Energy Technology Data Exchange (ETDEWEB)

    Gonnot, F.M.; Martin, Ph.

    2011-07-01

    The first part of this report gives an overview of technical definitions, of economic aspects and of the international situation: presentation of non conventional hydrocarbons, of exploitation techniques (horizontal drilling, hydraulic fracturing), strategic impact of these new resources in Northern America, in the World, in the European Union and in France. The second part describes the frightening American example, the impact of this exploitation on land (new pits are always to be drilled, large surfaces are concerned, unceasing road traffic), the risks associated with the use of chemical additives, and the problem of protection of water resources (consumption of huge quantities of water, risks of water contamination, the issue of used waters), and of atmospheric release (greenhouse gas emissions). The third part outlines the current imperfections of the French mining code, its weaknesses and its necessary reform

  6. Information report on greenhouse gas emission trading systems, in the name of the Sustainable Development and Land Management Commission; Rapport d'information depose en application de l'article 145 du reglement par la mission d'information sur les marches de quotas de gaz a effet de serre au nom de la commission du developpement durable et de l'amenagement du territoire

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    In its first part, this report explains the choice of trading systems due to the impossibility to define taxes on carbon emissions and to the influence of international negotiations. It also describes the operation of the European system with its three allocation phases (an experimental framework between 2005 and 2007, an actually constraining framework between 2008 and 2012, and a sustainable frame from 2013), and outlines the realistic character of emission reduction objective by 2020. It identifies and discusses the weaknesses of the European system, notably due to an insufficiently regulated market and to a partial taking into account of emission. The second part identifies ways to improve the system by extending it (including new sectors, taking some particular emissions into account, and valuing carbon sequestration), by preserving the competitiveness of European industries, and by aiming at the construction of a de-carbonated Europe

  7. Report on the behalf of the finance, general economy and budget control commission on the finance bill for 2012: Appendix 14: ecology, sustainable development and planning. Energy; Rapport fait au nom de la Commission des Finances, de l'Economie Generale et du Controle Budgetaire sur le projet de loi de finances pour 2012 (n. 3775), Annexe n.14 ecologie, developpement et amenagement durables. Energie

    Energy Technology Data Exchange (ETDEWEB)

    Carrez, G.

    2011-07-01

    The author first addresses aspect of the finance bill concerning past decisions and the past energy production context and policy: the after-mining management, measure in favour of Lorraine, an electricity cost which misses out the plant dismantling financing. Then, he addresses the policy in favour of renewable energies: renewal of hydroelectric concessions, tax support for energy sobriety. He comments the on-going audit of AREVA and EDF, and notably addresses the EPR construction issue (in Finland) and the purchase of UraMin by AREVA

  8. Which toolkit for durability evaluation as regards chloride ingress into concrete ? Part II : Development of a performance approach based on durability indicators and monitoring parameters

    OpenAIRE

    BAROGHEL BOUNY, V

    2002-01-01

    This paper series includes two parts : I - Comparison between various methods for assessing the chloride diffusion coefficient of concrete in saturated conditions, and II - Development of a performance approach based on durability indicators and monitoring parameters. The chloride diffusion coefficient appears as a key-parameter in the theorical laws involved in transfer-related durability of concrete, an hence in the prediction of the service lifetime of reinforced structures. Consequently, ...

  9. Preventive analgesia

    DEFF Research Database (Denmark)

    Dahl, Jørgen B; Kehlet, Henrik

    2011-01-01

    This paper will discuss the concepts of pre-emptive and preventive analgesia in acute and persistent postsurgical pain, based on the most recent experimental and clinical literature, with a special focus on injury-induced central sensitization and the development from acute to chronic pain. Recent...... findings: The nature of central sensitization during acute and chronic postsurgical pain share common features, and there may be interactions between acute and persistent postoperative pain. The term ‘pre-emptive analgesia’ should be abandoned and replaced by the term ‘preventive analgesia’. Recent studies...... of preventive analgesia for persistent postoperative pain are promising. However, clinicians must be aware of the demands for improved design of their clinical studies in order to get more conclusive answers regarding the different avenues for intervention. Summary: The concept of preventive...

  10. Tuberculosis Prevention

    Science.gov (United States)

    ... Skip Content Marketing Share this: Main Content Area Tuberculosis (TB) Prevention TB is an airborne disease and ... patients. Many people who are infected with Mycobacterium tuberculosis ( Mtb ) do not get sick or spread the ...

  11. Durable Late Blight Resistance in Potato Through Dynamic Varieties Obtained by Cisgenesis

    NARCIS (Netherlands)

    Haverkort, A.J.; Boonekamp, P.M.; Hutten, R.; Jacobsen, E.; Lotz, L.A.P.; Kessel, G.J.T.; Vossen, J.H.; Visser, R.G.F.

    2016-01-01

    From 2006 through 2015, a research project on Durable Resistance in potato against Phytophthora (DuRPh) was carried out at Wageningen University and Research Centre. Its objective was to develop a proof of principle for durable resistance against late blight by cisgenesis. This public-funded proj

  12. 40 CFR 86.1823-08 - Durability demonstration procedures for exhaust emissions.

    Science.gov (United States)

    2010-07-01

    ... guidelines of the high mileage IUVP program (ref: 40 CFR 86.1845-04). (3) Manufacturers may use previously...) Emission component durability. . For guidance see 40 CFR 86.1823-01(e). (h) Application of the durability... diesel fueled vehicles or vehicles which do not use a catalyst as the principle after-treatment...

  13. Durability of Dukovany shallow land repository engineered barriers. Appendix 7: Czech Republic

    International Nuclear Information System (INIS)

    The main aim of this project was to explore the durability of engineering barriers used at Dukovany shallow land repository as a support of safety assessments. This appendix summarises the principal results focused on durability of asphaltopropyleneconcrete (APC) hydroisolation and steel reinforced concrete construction

  14. HIV Prevention

    Centers for Disease Control (CDC) Podcasts

    2012-02-01

    Dr. Kevin Fenton, Director of CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, talks about steps people can take to protect their health from HIV.  Created: 2/1/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 2/1/2012.

  15. Assessing the durability of concrete regarding ASR[ACI SP-234-15

    Energy Technology Data Exchange (ETDEWEB)

    Stark, J.; Giebson, C. [Bauhaus Univ., Weimar (Germany). F.A. Finger-Inst. for Building Materials Sciences

    2006-07-01

    Damages on concrete structures caused by alkali-aggregate reaction (AAR) were discussed. In Germany, the first damage caused by the alkali-silica reaction (ASR) occurred on a bridge that was built in 1964 and which had to be demolished in 1968 due to the loss of structural stability. As a result of intensive research into the cause of damage, the first Alkali-Guideline was published in 1974 by the German Committee for Reinforced Concrete. The guideline made it possible to classify alkali-reactive aggregates which contained opaline sandstone and flint. In order to prevent deleterious ASR, the guidelines proposed clear measures for moisture, external alkali supply and cement content. The guidelines were revised many times over the past decades to include other rock type aggregates that also posed problems. The guideline is going to be revised one more time to include testing methods that assess the influence of an external alkali supply, such as de-icing solutions, for pavement concretes. The cyclic climate storage was used and proved as an appropriate method. It was concluded that the new mortar bar test and cyclic climate storage represent more opportunities to assess the durability of concretes regarding ASR due to alkali-reactive slow/late aggregates. 17 refs., 2 tabs., 11 figs.

  16. Use of fiber-reinforced composites to improve the durability of bridge elements

    Science.gov (United States)

    Garon, Ronald; Balaguru, P. N.; Cao, Yong; Lee, K. Wayne

    2000-04-01

    Fiber composites made of carbon fibers and organic polymers are being used to strengthen plain, reinforced, and prestressed concrete structures. The composites are becoming more popular as compared to traditional strengthening with steel plates and jackets because they do not corrode and also have a very high strength to weight ratio. Organic polymers have been used as protective coatings for more than thirty years. The impermeable membrane of the polymer seals the concrete surface of the structures preventing the ingress of salts. Their main drawback is their inability to release vapor pressure buildup that causes damage in the concrete and delamination of the bonded fiber reinforced plastic. As a result of this and other weaknesses in the organic polymers, a new generation of breathable coating materials is being developed. These compositions range from epoxy modified portland cement coatings to completely inorganic silicate systems. The durability of five of the most promising compositions was evaluated under freeze-thaw, wet-dry, and scaling conditions. The silicate matrix was also used to bond carbon tows and fabrics to unreinforced concrete members. These beams were tested after exposure to wet-dry and scaling conditions. The results indicate that the inorganic matrix can be effectively used for repairs. The carbon tows can be used to replace the existing corroded reinforcing bars. The possibility of embedding optical fibers with the carbon fibers to monitor the field performance is being studied.

  17. Durable superhydrophilic/phobic surfaces based on green patina with corrosion resistance.

    Science.gov (United States)

    Cho, Handong; Lee, Jeongwon; Lee, Sangmin; Hwang, Woonbong

    2015-03-14

    Special wetting surfaces with superhydrophilicity or superhydrophobicity have attracted great interest because of their potential for practical applications. However, since the special wetting surface may be used in a severe environment, including polluted air and seawater, it is necessary to develop a durable special wetting surface with excellent corrosion-resistance. Here, we report a new strategy for robust superhydrophilic or superhydrophobic green patina surfaces on copper substrates with superior corrosion resistance and adhesion strength, which have great potential for treating marine pollution. The as-prepared surfaces exhibited superhydrophilicity with underwater superoleophobicity or superoleophilicity with under-oil superhydrophobicity, which allowed them to selectively separate oil and water with high efficiency. More importantly, the surface displayed not only good mechanical stability but also chemical stability in corrosive liquids owing to the intrinsic properties of the patina and hydrophobic coating. Furthermore, the surface can be utilized as coating material for the decoration of building exteriors and prevention from surface fouling. We believe that our proposed method would make it possible to develop engineering materials that require robust anti-fouling, anti-frost, and anti-corrosion properties in marine environments. PMID:25670158

  18. Durability of commercial aircraft and helicopter composite structures

    International Nuclear Information System (INIS)

    The development of advanced composite technology during the past decade is discussed. Both secondary and primary components fabricated with boron, graphite, and Kevlar composites are evaluated. Included are spoilers, rudders, and fairings on commercial transports, boron/epoxy reinforced wing structure on C-130 military transports, and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on commercial helicopters. The development of composite structures resulted in advances in design and manufacturing technology for secondary and primary composite structures for commercial transports. Design concepts and inspection and maintenance results for the components in service are reported. The flight, outdoor ground, and controlled laboratory environmental effects on composites were also determined. Effects of moisture absorption, ultraviolet radiation, aircraft fuels and fluids, and sustained tensile stress are included. Critical parameters affecting the long term durability of composite materials are identified

  19. Durability and Performance of High Performance Infiltration Cathodes

    DEFF Research Database (Denmark)

    Samson, Alfred Junio; Søgaard, Martin; Hjalmarsson, Per; Hjelm, Johan; Bonanos, Nikolaos; Foghmoes, Søren Preben Vagn; Ramos, Tania

    2013-01-01

    The performance and durability of solid oxide fuel cell (SOFC) cathodes consisting of a porous Ce0.9Gd0.1O1.95 (CGO) infiltrated with nitrates corresponding to the nominal compositions La0.6Sr0.4Co1.05O3-δ (LSC), LaCoO3-δ (LC), and Co3O4 are discussed. At 600°C, the polarization resistance, Rp...... infiltrate but also from a better surface exchange property. A 450h test of an LSC-infiltrated CGO cathode showed an Rp with final degradation rate of only 11mΩcm2kh-1. An SOFC with an LSC-infiltrated CGO cathode tested for 1,500h at 700°C and 0.5Acm-2 (60% fuel, 20% air utilization) revealed no measurable...... degradation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim....

  20. Carbonation-Related Microstructural Changesin Long-Term Durability Concrete

    Directory of Open Access Journals (Sweden)

    Cláudio A. Rigo da Silva

    2002-09-01

    Full Text Available This paper discusses the effects of carbonation on the microstructure of Portland cement concrete for long-term durability applications. A class C40 concrete (characteristic compression strength between 40 MPa and 44 MPa on the 28th day, according to Brazilian standard NBR 8953 was chosen for the experimental study of the carbonation effects, from which test samples were molded for accelerated test under a 100%-CO2 atmosphere after physical and mechanical characterization. It was observed that carbonation provoked a reduction of 5% to 12% of the concrete open porosity accessible to water. Flexural strength values obtained after the carbonation tests revealed a decrease of 12% and 25% in relation to the values obtained before tests on the 28th and 91st days, respectively.

  1. Durability of Cement Composites Reinforced with Sisal Fiber

    Science.gov (United States)

    Wei, Jianqiang

    This dissertation focuses mainly on investigating the aging mechanisms and degradation kinetics of sisal fiber, as well as the approaches to mitigate its degradation in the matrix of cement composites. In contrast to previous works reported in the literature, a novel approach is proposed in this study to directly determine the fiber's degradation rate by separately studying the composition changes, mechanical and physical properties of the embedded sisal fibers. Cement hydration is presented to be a crucial factor in understanding fiber degradation behavior. The degradation mechanisms of natural fiber consist of mineralization of cell walls, alkali hydrolysis of lignin and hemicellulose, as well as the cellulose decomposition which includes stripping of cellulose microfibrils and alkaline hydrolysis of amorphous regions in cellulose chains. Two mineralization mechanisms, CH-mineralization and self-mineralization, are proposed. The degradation kinetics of sisal fiber in the cement matrix are also analyzed and a model to predict the degradation rate of cellulose for natural fiber embedded in cement is outlined. The results indicate that the time needed to completely degrade the cellulose in the matrix with cement replacement by 30wt.% metakaolin is 13 times longer than that in pure cement. A novel and scientific method is presented to determine accelerated aging conditions, and to evaluating sisal fiber's degradation rate and durability of natural fiber-reinforced cement composites. Among the static aggressive environments, the most effective approach for accelerating the degradation of natural fiber in cement composites is to soak the samples or change the humidity at 70 °C and higher temperature. However, the dynamic wetting and drying cycling treatment has a more accelerating effect on the alkali hydrolysis of fiber's amorphous components evidenced by the highest crystallinity indices, minimum content of holocellulose, and lowest tensile strength. Based on the

  2. Durability of Lacquered Aluminium Profile Considering Tropical Weather Conditions

    Directory of Open Access Journals (Sweden)

    Rigoberto Marrero Águila

    2013-11-01

    Full Text Available Searching for solutions against the degradation of materials by corrosion effect, is a common practice to use alloys such as aluminium instead of steel due to the advantages obtained. The lacquered aluminium profiles can substitute other materials like wood, in the carpentry production, becoming an economic saving. There is an increasingly use of aluminium replacing other traditional materials in the constructions in process, but its quality has been reduced in a considerable amount of installations. In this research, aluminium profiles from five different sources were submitted to a trial in natural exposition conditions at the Tropical weather condition Testing Lab, in order to evaluate their behaviour and establish, for the first time in our country, standing rules for lacquered aluminium profiles to be strictly fulfilled by manufacturers and importers. The results will allow modifying thickness standards of this type of coating, to guaranty its durability and to eliminate the failures provoked by our high severe weather conditions.

  3. Durability Study of SOFCs Under Cycling Current Load Conditions

    DEFF Research Database (Denmark)

    Hagen, Anke; Hendriksen, Peter Vang; Frandsen, Henrik Lund;

    2009-01-01

    In fuel cell applications, the cells must be able to withstand varying operating conditions. Anode supported solid oxide fuel cells were tested under cycling current load in order to determine the durability and possibly identify degradation mechanisms. At 750 °C and a cycling between zero and 0.......75 A cm-2, the cell voltage degradation rate was similar to tests with the corresponding high constant current density. However, by analyzing the impedance spectra it was found that anode degradation was becoming more important when going from constant to cycling conditions. Running the cycling load...... tests at 850 °C, the cells degraded similarly as under the corresponding constant current load whereas, in some cases, cells failed mechanically after a few hundred hours. These cells did not experience severe additional degradation due to the cycling of the current density until the point of failure...

  4. Durability and Micro-structure of Reactive Powder Concrete

    Institute of Scientific and Technical Information of China (English)

    LIU Juanhong; SONG Shaomin; WANG Lin

    2009-01-01

    Durability of traditional reactive powder concrete(RPC)with rich cement and high volume of fly-ash reactive powder concrete(FRPC)were studied.The X-diffraction and scanning electron microscope(SEM)measurement was imployed to analyze the microstructure.The results show that both types of RPC have higher compressive strength,less volume shrinkage ratio and better carbonation-,chloride-,freezing-resistances than the conventional concrete.The results of X-diffraction indicate that they basically have C-S-H as the main composition without Ca(OH)_2 crystal and ettringite.SEM results show that hydration products of FRPC is mainlyⅢ-C-S-H which is piled up closely like densely arranged stone body and it has very compacted structure,in addition,Ca/Si ratio of C-S-H gel is lower than 1.5.

  5. Investigation into digital print hard copy quality, longevity and durability

    International Nuclear Information System (INIS)

    The main purpose of the research project was to investigate whether deskjet ink jet printing could produce A-4 size images on a par with conventional silver halide continuous tone photographic media prints. To this end, equivalent images were produced using both dye-based and pigment-based deskjet ink jet prints. To assist the research project, a multi-cultured array of observers were enlisted to give individual responses to a range of specific questions appertaining to the image characteristics of the A-4 size images produced. In addition, in order to assess the image stability and print durability of both the conventional silver halide prints and the ink jet prints, a range of laboratory tests were undertaken in the areas of light fastness, water fastness and both dry and wet rub fastness.

  6. Contact and Bending Durability Calculation for Spiral-Bevel Gears

    Science.gov (United States)

    Vijayakar, Sandeep

    2016-01-01

    The objective of this project is to extend the capabilities of the gear contact analysis solver Calyx, and associated packages Transmission3D, HypoidFaceMilled, HypoidFaceHobbed. A calculation process for the surface durability was implemented using the Dowson-Higginson correlation for fluid film thickness. Comparisons to failure data from NASA's Spiral Bevel Gear Fatigue rig were carried out. A bending fatigue calculation has been implemented that allows the use of the stress-life calculation at each individual fillet point. The gears in the NASA test rig did not exhibit any bending fatigue failure, so the bending fatigue calculations are presented in this report by using significantly lowered strength numbers.

  7. Performance and durability of solid oxide electrolysis cells

    DEFF Research Database (Denmark)

    Hauch, Anne; Jensen, Søren H; Ramousse, Severine; Mogensen, Mogens Bjerg

    2006-01-01

    Solid oxide fuel cells produced at Riso National Laboratory have been tested as electrolysis cells by applying an external voltage. Results on initial performance and durability of such reversible solid oxide cells at temperatures from 750 to 950 degrees C and current densities from -0.25 A/cm(2......) to -0.50 A/cm(2) are reported. The full cells have an initial area specific resistance as low as 0.27 Omega cm(2) for electrolysis operation at 850 degrees C. During galvanostatic long-term electrolysis tests, the cells were observed to passivate mainly during the first similar to 100 h of...... electrolysis. Cells that have been passivated during electrolysis tests can be partly activated again by operation in fuel cell mode or even at constant electrolysis conditions after several hundred hours of testing....

  8. Commerce international, clause sociale et développement durable

    OpenAIRE

    Reis, Patrice

    2010-01-01

    La dimension sociale du développement durable peut être illustrée par les débats récurrents portant sur l'insertion d'une clause sociale dans le cadre des règles de droit du commerce international portée par l'OMC. Cependant cette insertion s'avérant de plus en plus difficile, le cadre multilatéral des négociation commerciales internationales tend à être mis de coté par les Etats afin de privilégier un cadre bilatéral où la clause sociale peut plus facilement être utilisée. Article objet d'un...

  9. Développement durable, gouvernance et démocratie

    OpenAIRE

    Pinson, Gilles

    2006-01-01

    Les termes de développement durable et de gouvernance sont aujourd'hui fréquemment associés. Tout se passe comme si l'on considérait désormais qu'une bonne prise en charge des problèmes d'environnement et de développement économique ne passait plus uniquement par le recours à des systèmes technologiques éco-compatibles ou à des modèles économiques soucieux de la préservation des ressources naturelles et des équilibres sociaux, mais aussi par la mise en place de systèmes organisationnels, de s...

  10. Durability of commercial aircraft and helicopter composite structures

    Science.gov (United States)

    Dexter, H. B.

    1982-01-01

    The development of advanced composite technology during the past decade is discussed. Both secondary and primary components fabricated with boron, graphite, and Kevlar composites are evaluated. Included are spoilers, rudders, and fairings on commercial transports, boron/epoxy reinforced wing structure on C-130 military transports, and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on commercial helicopters. The development of composite structures resulted in advances in design and manufacturing technology for secondary and primary composite structures for commercial transports. Design concepts and inspection and maintenance results for the components in service are reported. The flight, outdoor ground, and controlled laboratory environmental effects on composites were also determined. Effects of moisture absorption, ultraviolet radiation, aircraft fuels and fluids, and sustained tensile stress are included. Critical parameters affecting the long term durability of composite materials are identified.

  11. Quantify and improve PEM fuel cell durability. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Grahl-Madsen, L.; Odgaard, M.; Munksgaard Nielsen, R. (IRD Fuel Cell A/S, Svendborg (Denmark)); Li, Q.; Jensen, Jens Oluf (Technical Univ. of Denmark, Dept. of Chemistry, Kgs. Lyngby (Denmark)); Andersen, Shuang Ma; Speder, J.; Skou, E. (Syddansk Univ. (SDU), Odense (Denmark))

    2010-07-01

    The aim of the present project is to systematically quantify and improve the durability of the PEM FC including the following three PEM FC variants: LT PEM FC, DMFC, and HT PEM FC. Different factors influencing dissolution properties of noble metal catalyst platinum and platinum-ruthenium alloy has been studied. The dissolution was found to increase by increasing the CV cycle upper potential limit, number of potential cycles, solution acidity, oxygen partial pressure, involvement of chloride, and temperature. Ruthenium was found to deteriorate ten (10) times faster than platinum catalyst; and carbon supported catalyst (Pt: 20%, Ru: up to 100%) deteriorate ten (10) times faster than non-supported catalyst (Pt: 2%, Ru: 30%) at the same condition. Loss of sulphonic acid groups and fluoride from perfluorinated sulfonic acid membrane was confirmed by different techniques, which locally leads to loss of acidity, and consequently enhances dissolution of noble metal catalyst. Degradation of Nafion ionomer in the electrode was enhanced by noble metal catalyst and the thermal decomposition properties has synergetic effect with carbon degradation. Hydrophobicity of GDL and electrode on GDL were found to degrade e.g. radical attack, oxidation, and physical wear out. The very top micro surface structure turned out to be responsible for wetting property after chemical ageing. Optimal catalyst and ionomer ratio is also reflected in contact angle value, which can be understood in terms of catalyst/carbon - ionomer affinity and layered structure. Long-term tested and 'virgin' LT PEM MEAs have been characterised with respect to SEM, TEM, EDS, and XRD. Both failed and well-functioning MEAs have been characterised. The Post Mortem analysis has shown and quantified degradation mechanisms like catalyst growth and carbon corrosion. Furthermore, the effect of fuel starvation was shown by pronounced Ru-catalyst band within the membrane. The catalyst coarsening observed after

  12. The durability of beneficial health effects associated with expressive writing.

    Science.gov (United States)

    Sloan, Denise M; Feinstein, Brian A; Marx, Brian P

    2009-10-01

    This study examined the durability of benefits associated with expressive writing. Sixty-eight college undergraduates completed measures of physical and psychological health at the beginning of their first year and were then randomized to either an expressive writing or a control writing condition. Changes in physical health, psychological health (i.e., depression, stress, and anxiety), and academic performance were assessed two, four, and six months later. Findings indicated that participants assigned to the expressive writing condition reported less depression symptom severity at the two-month follow-up assessment relative to participants assigned to the control condition. However, these symptom reductions were not observed at any of the subsequent follow-up assessments. No significant changes were reported for physical health complaints, stress symptoms,anxiety symptoms, or academic performance. These findings suggest that,among first-year college students, expressive writing may provide some shortterm relief for certain symptoms. PMID:19333797

  13. Investigation into digital print hard copy quality, longevity and durability

    Energy Technology Data Exchange (ETDEWEB)

    Kazlauciunas, Algy; Zhang Mingyu [Department of Colour Science, School of Chemistry, University of Leeds LS2 9JT (United Kingdom); Ball, Jeff, E-mail: ccdak@leeds.ac.u [Nazdar Limited, Heaton Mersey, Stockport, Cheshire SK4 3EG (United Kingdom)

    2010-06-01

    The main purpose of the research project was to investigate whether deskjet ink jet printing could produce A-4 size images on a par with conventional silver halide continuous tone photographic media prints. To this end, equivalent images were produced using both dye-based and pigment-based deskjet ink jet prints. To assist the research project, a multi-cultured array of observers were enlisted to give individual responses to a range of specific questions appertaining to the image characteristics of the A-4 size images produced. In addition, in order to assess the image stability and print durability of both the conventional silver halide prints and the ink jet prints, a range of laboratory tests were undertaken in the areas of light fastness, water fastness and both dry and wet rub fastness.

  14. Entrepreneuriat social et développement durable : Quelles perspectives

    OpenAIRE

    Boutillier, Sophie

    2008-01-01

    La crise économique des années 1970 a provoqué dans les pays industrialisés et en développement des bouleversements économiques, sociaux, technologiques et politiques très importants. Le modèle économique de l'après guerre est face à ses limites. La reconstruction est achevée. Les besoins solvables que l'entreprise fordiste pouvait offrir sont saturés. La solution proposée combine quatre éléments interdépendants : l'entrepreneuriat, le micro crédit, le développement durable et le recul de l'E...

  15. Durability properties for adhesively bonded structural aerospace applications

    International Nuclear Information System (INIS)

    This paper reports on the importance of good bond durability of adhesively joined aerospace components which has been recognized for many years. Military and civilian aircraft are exposed to harsh environments in addition to severe thermal and stress cycles during their service lives. Moisture is responsible for the majority of bond failures in the field. The presence of surface contaminants (e.g., fluoride, silicones) and the non-neutral pH of poor rinse water are common causes of adhesion problems in production environments. Honeycomb panels, stringer skins, doubler plates and core cowl assemblies are bonded joint structures that are subject to environmental- or contaminant-induced debonding. The identification and characterization of the causes of such bond failures leads to improved production quality, yield and cost reduction

  16. Low power consumption and high temperature durability for radiation sensor

    International Nuclear Information System (INIS)

    Low power consumption and high temperature operation are important in an environmental monitoring system. The power consumption of 3 mW is achieved for the radiation sensor using low voltage operational amplifier and comparator in the signal processing circuit. The leakage reverse current of photodiode causes the charge amplifier saturation over 50degC. High temperature durability was improved by optimizing the circuit configuration and the values of feedback resistance and capacitance in the charge amplifier. The pulse response of the radiation sensor was measured up to 55degC. The custom detection circuit was designed by 0.6 μm CMOS process at 5-V supply voltage. The operation temperature was improved up to 65degC. (author)

  17. Application of the Durability Reinforcement Technique on the Frame Structure

    International Nuclear Information System (INIS)

    In this paper, the technique to reinforce the durability performance of structure using the sensitivity information for the frame structure is applied. The fatigue life calculation for the frame structure is performed from the quasi-static and transient analysis and the characteristics of two methods are compared for the fatigue analysis. Then the reinforcement technique is applied. First, some design variables related to the locations of fatigue failure is selected. Then sensitivities of fatigue life at fracture points with respect to the variation of design variables are calculated and the vector composed of gaps between the target life and initial life cycles is calculated. If the number of fatigue fracture points is same as the number of design variables, the variations of the design variables are calculated from the linear algebraic equation. If not, the variations of the design variables are calculated from the optimization formulation with the constraints

  18. Moisture Durability Assessment of Selected Well-insulated Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Boudreaux, Philip R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kehrer, Manfred [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hun, Diana E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jackson, Roderick K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Desjarlais, Andre Omer [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    This report presents the results from studying the hygrothermal performance of two well-insulated wall assemblies, both complying with and exceeding international building codes (IECC 2015 2014, IRC 2015). The hygrothermal performance of walls is affected by a large number of influential parameters (e.g., outdoor and indoor climates, workmanship, material properties). This study was based on a probabilistic risk assessment in which a number of these influential parameters were simulated with their natural variability. The purpose of this approach was to generate simulation results based on laboratory chamber measurements that represent a variety of performances and thus better mimic realistic conditions. In total, laboratory measurements and 6,000 simulations were completed for five different US climate zones. A mold growth indicator (MGI) was used to estimate the risk of mold which potentially can cause moisture durability problems in the selected wall assemblies. Analyzing the possible impact on the indoor climate due to mold was not part of this study. The following conclusions can be reached from analyzing the simulation results. In a hot-humid climate, a higher R-value increases the importance of the airtightness because interior wall materials are at lower temperatures. In a cold climate, indoor humidity levels increase with increased airtightness. Air leakage must be considered in a hygrothermal risk assessment, since air efficiently brings moisture into buildings from either the interior or exterior environment. The sensitivity analysis of this study identifies mitigation strategies. Again, it is important to remark that MGI is an indicator of mold, not an indicator of indoor air quality and that mold is the most conservative indicator for moisture durability issues.

  19. Freezing and Thawing Durability of Very High Strength Concrete

    Directory of Open Access Journals (Sweden)

    Sameer Hamoush

    2011-01-01

    Full Text Available Problem statement: The newly developed Very High Strength Concrete (VHSC, having compressive strengths of 29 ksi and flexural strengths of 6 ksi, represents a breakthrough in concrete technology. Study to further enhance the properties of this new concrete is continuing. Approach: The objective of this study is to investigate the effect of exposing Very High Strength Concrete (VHSC specimens to rapid freeze/thaw cycles. Twenty one specimens were tested according to the Standards of the American Society for Testing and Materials ASTM C215, ASTM C666 and ASTM C78. Results: One hundred freeze/thaw cycles were performed on the VHSC specimens. Change in specimen’s dimensions and material’s properties were recorded at zero, forty, seventy and one hundred cycles. Dimensions and properties considered were: dimension of cross section, length, weight, Dynamic Moduli, Poisson’s Ratio, durability factor and Modulus of Rupture. Conclusion/Recommendations: The test results indicated that VHSC is good freeze-thaw resistance (durability factor > 85% and can avoid freeze/thaw damage. Freeze- thaw cycling did not significantly affect VHSC specimens’ cross sectional dimensions, length, or Poisson’s Ratio. However, there was a decrease in the specimens’ weight with the increase in number of freeze/thaw cycles, but the decrease was very slim indicating little or no deterioration has occur. Moreover, the fine voids exist in VHSC greatly lower the freezing point of any trapped water, making the material less susceptible to Freeze- Thaw damage.

  20. Effect of glass composition on waste form durability: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, A.J.G.; Mazer, J.J.; Ebert, W.L. [Argonne National Lab., IL (United States). Chemical Technology Div.

    1994-11-01

    This report reviews literature concerning the relationship between the composition and durability of silicate glasses, particularly glasses proposed for immobilization of radioactive waste. Standard procedures used to perform durability tests are reviewed. It is shown that tests in which a low-surface area sample is brought into contact with a very large volume of solution provide the most accurate measure of the intrinsic durability of a glass composition, whereas high-surface area/low-solution volume tests are a better measure of the response of a glass to changes in solution chemistry induced by a buildup of glass corrosion products. The structural chemistry of silicate and borosilicate glasses is reviewed to identify those components with the strongest cation-anion bonds. A number of examples are discussed in which two or more cations engage in mutual bonding interactions that result in minima or maxima in the rheologic and thermodynamic properties of the glasses at or near particular optimal compositions. It is shown that in simple glass-forming systems such interactions generally enhance the durability of glasses. Moreover, it is shown that experimental results obtained for simple systems can be used to account for durability rankings of much more complex waste glass compositions. Models that purport to predict the rate of corrosion of glasses in short-term durability tests are evaluated using a database of short-term durability test results for a large set of glass compositions. The predictions of these models correlate with the measured durabilities of the glasses when considered in large groupings, but no model evaluated in this review provides accurate estimates of durability for individual glass compositions. Use of these models in long-term durability models is discussed. 230 refs.

  1. Effect of glass composition on waste form durability: A critical review

    International Nuclear Information System (INIS)

    This report reviews literature concerning the relationship between the composition and durability of silicate glasses, particularly glasses proposed for immobilization of radioactive waste. Standard procedures used to perform durability tests are reviewed. It is shown that tests in which a low-surface area sample is brought into contact with a very large volume of solution provide the most accurate measure of the intrinsic durability of a glass composition, whereas high-surface area/low-solution volume tests are a better measure of the response of a glass to changes in solution chemistry induced by a buildup of glass corrosion products. The structural chemistry of silicate and borosilicate glasses is reviewed to identify those components with the strongest cation-anion bonds. A number of examples are discussed in which two or more cations engage in mutual bonding interactions that result in minima or maxima in the rheologic and thermodynamic properties of the glasses at or near particular optimal compositions. It is shown that in simple glass-forming systems such interactions generally enhance the durability of glasses. Moreover, it is shown that experimental results obtained for simple systems can be used to account for durability rankings of much more complex waste glass compositions. Models that purport to predict the rate of corrosion of glasses in short-term durability tests are evaluated using a database of short-term durability test results for a large set of glass compositions. The predictions of these models correlate with the measured durabilities of the glasses when considered in large groupings, but no model evaluated in this review provides accurate estimates of durability for individual glass compositions. Use of these models in long-term durability models is discussed. 230 refs

  2. A study on the methodology to ensure long-term durability of low and intermediate level radwaste disposal concrete structure

    International Nuclear Information System (INIS)

    The concrete structure is being considered for the main engineered barrier of low and intermediate level radwaste disposal facility. Concrete of low permeability can minimize infiltration of water and effectively prevent release of nuclide to ecosystem. But if concrete degrades, structural stability of disposal structure will decrease while permeability increase, resulting in increased possibility of nuclide release due to water infiltration. Therefore disposal concrete structure degradation shall be minimized to maintain capacity of nuclide isolation. The typical causes of concrete structure degradation are sulfide attack, reinforcement corrosion due to chloride attack, leaching of calcium hydroxide, alkali-aggregate reaction and repeated freezing-thawing. The common cause of these degradation processes is infiltration of water or adverse chemicals into concrete. Based on the study of these degradation characteristics and mechanisms of concrete structure, the methodology of design and service life evaluation of concrete structure as an engineered barrier are reviewed to ensure its long-term durability

  3. Editorial : Institutionnalisation du développement durable et émergence d'un marketing durable

    OpenAIRE

    Béji-Bécheur, Amina; Ozcaglar-Toulouse, Nil

    2014-01-01

    Le développement durable est aujourd'hui introduit dans les discours comme un modèle alternatif et légitime pour répondre à un problème majeur de notre époque contemporaine : il est urgent de combiner à la fois le développement économique et le respect des ressources naturelles, des droits sociaux et de l'équité dans la répartition de la richesse créée. Dans ce contexte, la responsabilité des acteurs du marché s'élargit au périmètre défini par le rapport Brundtland (1987). Ce dernier question...

  4. Impact of Sn/F Pre-Treatments on the Durability of Protective Coatings against Dentine Erosion/Abrasion.

    Directory of Open Access Journals (Sweden)

    Carolina Ganss

    Full Text Available For preventing erosive wear in dentine, coating with adhesives has been suggested as an alternative to fluoridation. However, clinical studies have revealed limited efficacy. As there is first evidence that Sn(2+ increases bond strength of the adhesive Clearfil SE (Kuraray, the aim of the present study was to investigate whether pre-treatment with different Sn(2+/F(- solutions improves the durability of Clearfil SE coatings. Dentine samples (eight groups, n=16/group were freed of smear layer (0.5% citric acid, 10 s, treated (15 s either with no solution (control, aminefluoride (AmF, 500 ppm F(-, pH 4.5, SnCl2 (800/1600 ppm Sn(2+; pH 1.5, SnCl2/AmF (500 ppm F(-, 800 ppm Sn(2+, pH 1.5/3.0/4.5, or Elmex Erosion Protection Rinse (EP, 500 ppm F-, 800 ppm Sn(2+, pH 4.5; GABA International, then rinsed with water (15 s and individually covered with Clearfil SE. Subsequently the specimens were subjected to an erosion/abrasion protocol consisting of 1320 cycles of immersion in 0.5% citric acid (5 °C/55 °C; 2 min and automated brushing (15 s, 200 g, NaF-toothpaste, RDA 80. As the coatings proved stable up to 1320 cycles, 60 modified cycles (brushing time 30 min/cycle were added. Wear was measured profilometrically. After SnCl2/AmF, pH 4.5 or EP pre-treatment all except one coating survived. In the other groups, almost all coatings were lost and there was no significant difference to the control group. Pre-treatment with a Sn(2+/F(- solution at pH 4.5 seems able to improve the durability of adhesive coatings, rendering these an attractive option in preventing erosive wear in dentine.

  5. Impact of Sn/F Pre-Treatments on the Durability of Protective Coatings against Dentine Erosion/Abrasion.

    Science.gov (United States)

    Ganss, Carolina; Lussi, Adrian; Peutzfeldt, Anne; Naguib Attia, Nader; Schlueter, Nadine

    2015-01-01

    For preventing erosive wear in dentine, coating with adhesives has been suggested as an alternative to fluoridation. However, clinical studies have revealed limited efficacy. As there is first evidence that Sn(2+) increases bond strength of the adhesive Clearfil SE (Kuraray), the aim of the present study was to investigate whether pre-treatment with different Sn(2+)/F(-) solutions improves the durability of Clearfil SE coatings. Dentine samples (eight groups, n=16/group) were freed of smear layer (0.5% citric acid, 10 s), treated (15 s) either with no solution (control), aminefluoride (AmF, 500 ppm F(-), pH 4.5), SnCl2 (800/1600 ppm Sn(2+); pH 1.5), SnCl2/AmF (500 ppm F(-), 800 ppm Sn(2+), pH 1.5/3.0/4.5), or Elmex Erosion Protection Rinse (EP, 500 ppm F-, 800 ppm Sn(2+), pH 4.5; GABA International), then rinsed with water (15 s) and individually covered with Clearfil SE. Subsequently the specimens were subjected to an erosion/abrasion protocol consisting of 1320 cycles of immersion in 0.5% citric acid (5 °C/55 °C; 2 min) and automated brushing (15 s, 200 g, NaF-toothpaste, RDA 80). As the coatings proved stable up to 1320 cycles, 60 modified cycles (brushing time 30 min/cycle) were added. Wear was measured profilometrically. After SnCl2/AmF, pH 4.5 or EP pre-treatment all except one coating survived. In the other groups, almost all coatings were lost and there was no significant difference to the control group. Pre-treatment with a Sn(2+)/F(-) solution at pH 4.5 seems able to improve the durability of adhesive coatings, rendering these an attractive option in preventing erosive wear in dentine. PMID:26075906

  6. A la recherche du développement socialement durable: concepts fondamentaux et principes de base

    Directory of Open Access Journals (Sweden)

    Jérôme Ballet

    2004-06-01

    Full Text Available Le développement est considéré comme durable lorsqu’il permet aux générations actuelles de satisfaire à leurs besoins sans compromettre la capacité des générations futures à satisfaire les leurs. Il faut pour cela que les générations futures détiennent au moins autant de ressources, sous la forme de capital ou de potentialités diverses, que la génération actuelle. Lorsqu’on considère la dimension sociale du développement durable, se pose alors la question du transfert des acquis ou potentialités d’une génération à l’autre. Ces potentialités prennent de multiples formes: capital humain (éducation, santé, capital social (liens sociaux, capacité à utiliser les potentialités disponibles, etc. Plus généralement, la durabilité sociale du développement demande d’aborder les conditions d’une transmission équitable des "capacités à faire et à être" (plus simplement "capabilités" d’une génération à l’autre. On attend donc d’un développement socialement durable qu’il protège les potentialités, renforce les capacités d’une génération donnée, et facilite leur transfert à la génération suivante. Cela implique d’examiner ce qui empêche la constitution de potentialités (trappes à pauvreté, l’amélioration des capacités (exclusion sociale et vulnérabilité et la transmission inter-générationnelle (inégalités. Dès lors, dans le cadre d’une éthique de la responsabilité, des principes de précaution sociale adéquats pourraient guider l’élaboration des politiques publiques.Sustainable development allows the current generation to satisfy its needs without compromising the capacity of future generations to satisfy theirs. This implies that future generations should have in hand at least as many resources, in terms of capital or various potentialities, than the current generation. The social dimension of sustainable development raises the issue of transmitting social assets

  7. Durability of particulate grouts: For isolation of low-level radioactive wastes

    International Nuclear Information System (INIS)

    Over the years particulate grouts have been used for isolating low-concerns that over time and following exposure to adverse environmental conditions, durability of the grouts may become grossly affected and contamination of groundwater system may result. To address some of these problems, a detailed laboratory study was conducted to characterize the fabric and performance of particulate grouts. Before and after exposure to several wet-dry and freeze-thaw cycles, pore size distribution measurements via mercury intrusion porosimetry, unconfined compressive strength, permeability and pulse velocity tests were performed on the studied grouts. Prediction equations were developed for assessing grout durability. Formulation factors: water/solid ratio; mix composition, and interaction between these were found to have significant statistical effect on both wet-dry and freeze-thaw durability of the studied grouts. Fly ash in excess of 30% by weight of total solids present, was found to lower durability considerably. Addition of 7 grams of fiber to the high fly ash grout mix improved durability. Silica fume caused considerable reduction in pore sizes and initial grain in strength, but appear to lower durability particularly under wet-dry conditions. Latex, showed a potential for use as an additive for formulating durable grout mixes. Statistically based design procedures were developed to aid the waste management practitioner to select a range of formulation factors that will assure a desired magnitude of behavior over a specified service period

  8. Bullying Prevention

    Science.gov (United States)

    Kemp, Patrice

    2016-01-01

    The focus of the milestone project is to focus on bridging the gap of bullying and classroom instruction methods. There has to be a defined expectations and level of accountability that has to be defined when supporting and implementing a plan linked to bullying prevention. All individuals involved in the student's learning have to be aware of…

  9. Prevent Pneumonia

    Centers for Disease Control (CDC) Podcasts

    2015-08-06

    CDC’s Matthew Westercamp explains what pneumonia is, its symptoms, and how to prevent it.  Created: 8/6/2015 by National Center for Immunization and Respiratory Diseases (NCIRD), Division of Bacterial Diseases (DBD), Respiratory Diseases Branch (RDB).   Date Released: 8/6/2015.

  10. Durability of cemented waste in repository and under simulated conditions

    International Nuclear Information System (INIS)

    The Romanian Radioactive Waste National Repository for low level and intermediate level radioactive waste was built in Baita - Bihor county, in an extinct uranium exploitation. The site is at 840 m above sea level and the host rock is crystalline with a low porosity, a good chemical homogeneity and impermeability, keeping these qualities over a considerable horizontal and vertical spans. To obtain the experimental data necessary for the waste form and package characterization together with the back-filling material behaviour in the repository environment, a medium term research programme (1996 - 2010) was implemented. The purpose of this experimental programme is to obtain a part of the data base necessary for the approach of medium and long term assessment of the safety and performance of Baita - Bihor Repository. The programme will provide: a deeper knowledge of the chemical species and reaction mechanisms, the structure, properties and performances of the final products. For safety reasons the behaviour of waste package, which is a main barrier, must be properly known in terms of long term durability in real repository conditions. Characterization of the behaviour includes many interactions between the waste package itself and the surrounding near field conditions such as mineralogy, hydrogeology and groundwater chemistry. To obtain a more deeper knowledge of the species and physical-chemical reactions participating in the matrix formation, as well as their future behaviour during the disposal period, a thorough XRD study started in 1998. For Romanian Radioactive Waste National Repository (DNDR) Baita - Bihor the following steps are planned for the conditioned waste matrix characterization in simulated and real conditions: - preparation and characterization of normal reference matrices based on different cement formulations; - preparation of reference simulated sludge cemented matrices containing iron hydroxide and iron phosphate; - selection of real and

  11. Unanticipated Effects of New Drug Availability on Antiretroviral Durability: Implications for Comparative Effectiveness Research

    Science.gov (United States)

    Eaton, Ellen F.; Tamhane, Ashutosh R.; Burkholder, Greer A.; Willig, James H.; Saag, Michael S.; Mugavero, Michael J.

    2016-01-01

    Background. Durability of antiretroviral (ARV) therapy is associated with improved human immunodeficiency virus (HIV) outcomes. Data on ARV regimen durability in recent years and clinical settings are lacking. Methods. This retrospective follow-up study included treatment-naive HIV-infected patients initiating ARV therapy between January 2007 and December 2012 in a university-affiliated HIV clinic in the Southeastern United States. Outcome of interest was durability (time to discontinuation) of the initial regimen. Durability was evaluated using Kaplan-Meier survival analyses. Cox proportional hazard analyses was used to evaluate the association among durability and sociodemographic, clinical, and regimen-level factors. Results. Overall, 546 patients were analyzed. Median durability of all regimens was 39.5 months (95% confidence interval, 34.1–44.4). Commonly prescribed regimens were emtricitabine and tenofovir with efavirenz (51%; median duration = 40.1 months) and with raltegravir (14%; 47.8 months). Overall, 67% of patients had an undetectable viral load at the time of regimen cessation. Discontinuation was less likely with an integrase strand transfer inhibitor (adjusted hazards ratio [aHR] = 0.35, P = .001) or protease inhibitor-based regimen (aHR = 0.45, P = .006) and more likely with a higher pill burden (aHR = 2.25, P = .003) and a later treatment era (aHR = 1.64, P drugs and combinations. Reduced durability mostly results from a preference for newly approved regimens rather than indicating failing therapy, as indicated by viral suppression observed in a majority of patients (67%) prior to regimen cessation. Durability is influenced by extrinsic factors including new drug availability and provider preference. Medication durability must be interpreted carefully in the context of a dynamic treatment landscape.

  12. Mine d’or et développement durable

    Directory of Open Access Journals (Sweden)

    Mouhamadou Lamine Diallo

    2009-03-01

    Full Text Available La relance des activités extractives au Sénégal oriental a commencé avec le projet minier de Sabodala. A l’image de sa région (Tambacounda, le village de Sabodala est une localité enclavée, caractérisée par la domination des activités traditionnelles (agriculture, orpaillage. La pauvreté y est perceptible à travers le manque d’emplois des jeunes, la rareté des infrastructures socio-économiques et des voies de communications. Ainsi, l’installation d’une industrie minière moderne suscite beaucoup d’espoirs auprès des populations villageoises, d’autant plus que l’Etat et la société adjudicataire du projet (Mineral Deposit Limited - MDL placent cette entreprise sous les auspices des principes du développement durable. Mais entre les intentions affichées et les réalités du terrain, l’écart est grand : à l’échelle locale, la mine produit des effets très ambivalents, difficiles à interpréter via les grilles d’analyse du développement durable.The revival of mining activities in western Senegal began with Sabodala mining project. Similarly to its region (Tambacounda, Sabodala is a remote village where traditional activities such as agriculture and gold digging are mainly practised. Poverty is perceived through joblessness among young people, the absence of social and economical infrastructures and the lack of thoroughfare. Therefore, the setting up of a new mining industry gives rise to hope within villagers and specially the government along with the allocated companies namely Mineral Deposits Limited (Mineral Deposit Limited - MDL, that are claiming sustainable development principles. However the gap between these demands and the results in the field induces to wonder whether it’s possible to establish a linkage between mining project and development at the local scale.

  13. High temperature PEM fuel cells - Degradation and durability

    Energy Technology Data Exchange (ETDEWEB)

    Araya, S.S.

    2012-12-15

    This work analyses the degradation issues of a High Temperature Proton Exchange Membrane Fuel Cell (HT-PEMFC). It is based on the assumption that given the current challenges for storage and distribution of hydrogen, it is more practical to use liquid alcohols as energy carriers for fuel cells. Among these, methanol is very attractive, as it can be obtained from a variety of renewable sources and has a relatively low reforming temperature for the production of hydrogen rich gaseous mixture. The effects on HT-PEMFC of the different constituents of this gaseous mixture, known as a reformate gas, are investigated in the current work. For this, an experimental set up, in which all these constituents can be fed to the anode side of a fuel cell for testing, is put in place. It includes mass flow controllers for the gaseous species, and a vapor delivery system for the vapor mixture of the unconverted reforming reactants. Electrochemical Impedance Spectroscopy (EIS) is used to characterize the effects of these impurities. The effects of CO were tested up to 2% by volume along with other impurities. All the reformate impurities, including ethanol-water vapor mixture, cause loss in the performance of the fuel cell. In general, CO{sub 2} dilutes the reactants, if tested alone at high operating temperatures (180 C), but tends to exacerbate the effects of CO if they are tested together. On the other hand, CO and methanol-water vapor mixture degrade the fuel cell proportionally to the amounts in which they are tested. In this dissertation some of the mechanisms with which the impurities affect the fuel cell are discussed and interdependence among the effects is also studied. This showed that the combined effect of reformate impurities is more than the arithmetic sum of the individual effects of reformate constituents. The results of the thesis help to understand better the issues of degradation and durability in fuel cells, which can help to make them more durable and

  14. Durability and performance optimization of cathode materials for fuel cells

    Science.gov (United States)

    Colon-Mercado, Hector Rafael

    The primary objective of this dissertation is to develop an accelerated durability test (ADT) for the evaluation of cathode materials for fuel cells. The work has been divided in two main categories, namely high temperature fuel cells with emphasis on the Molten Carbonate Fuel Cell (MCFC) cathode current collector corrosion problems and low temperature fuel cells in particular Polymer Electrolyte Fuel Cell (PEMFC) cathode catalyst corrosion. The high operating temperature of MCFC has given it benefits over other fuel cells. These include higher efficiencies (>50%), faster electrode kinetics, etc. At 650°C, the theoretical open circuit voltage is established, providing low electrode overpotentials without requiring any noble metal catalysts and permitting high electrochemical efficiency. The waste heat is generated at sufficiently high temperatures to make it useful as a co-product. However, in order to commercialize the MCFC, a lifetime of 40,000 hours of operation must be achieved. The major limiting factor in the MCFC is the corrosion of cathode materials, which include cathode electrode and cathode current collector. In the first part of this dissertation the corrosion characteristics of bare, heat-treated and cobalt coated titanium alloys were studied using an ADT and compared with that of state of the art current collector material, SS 316. PEMFCs are the best choice for a wide range of portable, stationary and automotive applications because of their high power density and relatively low-temperature operation. However, a major impediment in the commercialization of the fuel cell technology is the cost involved due to the large amount of platinum electrocatalyst used in the cathode catalyst. In an effort to increase the power and decrease the cathode cost in polymer electrolyte fuel cell (PEMFC) systems, Pt-alloy catalysts were developed to increase its activity and stability. Extensive research has been conducted in the area of new alloy development and

  15. Flexible, Mechanically Durable Aerogel Composites for Oil Capture and Recovery.

    Science.gov (United States)

    Karatum, Osman; Steiner, Stephen A; Griffin, Justin S; Shi, Wenbo; Plata, Desiree L

    2016-01-13

    More than 30 years separate the two largest oil spills in North American history (the Ixtoc I and Macondo well blowouts), yet the responses to both disasters were nearly identical in spite of advanced material innovation during the same time period. Novel, mechanically durable sorbents could enable (a) sorbent use in the open ocean, (b) automated deployment to minimize workforce exposure to toxic chemicals, and (c) mechanical recovery of spilled oils. Here, we explore the use of two mechanically durable, low-density (0.1-0.2 g cm(-3)), highly porous (85-99% porosity), hydrophobic (water contact angles >120°), flexible aerogel composite blankets as sorbent materials for automated oil capture and recovery: Cabot Thermal Wrap (TW) and Aspen Aerogels Spaceloft (SL). Uptake of crude oils (Iraq and Sweet Bryan Mound oils) was 8.0 ± 0.1 and 6.5 ± 0.3 g g(-1) for SL and 14.0 ± 0.1 and 12.2 ± 0.1 g g(-1) for TW, respectively, nearly twice as high as similar polyurethane- and polypropylene-based devices. Compound-specific uptake experiments and discrimination against water uptake suggested an adsorption-influenced sorption mechanism. Consistent with that mechanism, chemical extraction oil recoveries were 95 ± 2 (SL) and 90 ± 2% (TW), but this is an undesirable extraction route in decentralized oil cleanup efforts. In contrast, mechanical extraction routes are favorable, and a modest compression force (38 N) yielded 44.7 ± 0.5% initially to 42.0 ± 0.4% over 10 reuse cycles for SL and initially 55.0 ± 0.1% for TW, degrading to 30.0 ± 0.2% by the end of 10 cycles. The mechanical integrity of SL deteriorated substantially (800 ± 200 to 80 ± 30 kPa), whereas TW was more robust (380 ± 80 to 700 ± 100 kPa) over 10 uptake-and-compression extraction cycles. PMID:26701744

  16. Durability of fired clay bricks containing granite powder

    Directory of Open Access Journals (Sweden)

    Xavier, G. C.

    2012-06-01

    Full Text Available Over the past few decades, hundreds of papers have been published on the benefits of including rock powder as a raw material in fired clay brick manufacture. Very little has been written, however, about the durability and long-term behaviour of the final product. As a rule, the ceramic bricks used in construction in developing countries are fired at low temperatures, which detracts from their mechanical performance. This is particularly visible in harsh environmental conditions, where weathering causes severe deterioration. The present paper describes the impact of weathering on clay bricks containing from 0 to 10% granite powder, an industrial by-product. The specimens were fired at 500, 700 or 900 ºC and subsequently exposed to natural environmental conditions or accelerated laboratory weathering. Their physical and mechanical properties were evaluated to determine the effect of the composition of raw materials on fired clay product durability.

    En las últimas décadas se han publicado cientos de artículos sobre las ventajas de incluir polvo de roca como materia prima en la fabricación de los ladrillos cerámicos. Sin embargo, la durabilidad y el comportamiento a largo plazo del producto final han sido objeto de pocas investigaciones. Por lo general, los ladrillos cerámicos empleados en la construcción en los países en vías de desarrollo se cuecen a temperaturas bajas, lo que impide el desarrollo de sus propiedades mecánicas. Esto queda especialmente patente cuando las condiciones ambientales son severas, en cuyo caso la meteorización puede provocar un deterioro importante. En este artículo se describe el efecto de la meteorización en ladrillos cerámicos que incorporaban entre un 0 y un 10% de polvo de granito, que es un derivado industrial. Las probetas se cocieron a 500, 700 o 900 °C y luego se sometieron a condiciones ambientales naturales o a un proceso de laboratorio de meteorización acelerada. Se evaluaron sus

  17. Improving durability of Wood-polymer composite processed by gamma radiation against the Polyporus sanguineus fungus

    International Nuclear Information System (INIS)

    The study of wood durability was done measuring the wood weight lost after 90 days and the change of surface morphology. This study was done with the fungus Polyporus sanguineus in three wood species: Catahua (Hura crepitans L.), Mohena (Aniba amazonica Meiz), and Capirona (Calycophy spruceanum Be) without treatment and wood-polymer composite obtained by gamma irradiation. The Capirona and Mohena composites improve its durability, while the Catahua composite maintains its level of durability. Regarding surface morphology, there is no a significant change between the untreated woods and Capirona and Mohena composites. While the untreated Catahua shows deterioration of its surface. (orig.)

  18. Analysis Approach to Durability Based on Material Initial Fatigue Quality and S-N Curve

    Institute of Scientific and Technical Information of China (English)

    Yang Moucun; Nie Hong

    2007-01-01

    Based on probabilistic fracture mechanics approach, a new concept of material initial fatigue quality (MIFQ) is developed. Then,the relation between S-N curve and crack propagation curve is studied. From the study, a new durability analysis method is presented. In this method, S-N curve is used to determine crack growth rate under constant amplitude.loading and evaluate the effects of different factors on durability and then the structural durability is analyzed. The tests and analyses indicate that this method has lower dependence on testing, and higher accuracy, reliability and generality and is convenient for application.

  19. Price freezes, durables and residential electricity demand - Evidence from the Greater Buenos Aires

    Energy Technology Data Exchange (ETDEWEB)

    Casarin, Ariel; Delfino, Maria Eugenia

    2010-09-15

    This paper examines the determinants of residential electricity demand in the Greater Buenos Aires between 1997 and 2006. During the second half of this period, residential tariffs remained nominally fixed, while an income boom boosted up the sales of durables. This study differs from previous works in that it explicitly considers the impact of the stock of air-conditioners on residential demand. The paper reports short- and long-run elasticities and examines the contribution of prices and durables to recent demand growth. Simulations illustrate the impact of prices and durables on future demand.

  20. The effects of moisture and temperature variations on the long term durability of polymer concrete

    DEFF Research Database (Denmark)

    Barbosa, Ricardo; Hansen, Kurt Kielsgaard; Grelk, Bent; Wibholm, Esben

    2013-01-01

    The use of polymer concrete to precast products in construction presents normally many advantages compared to traditional concrete. Higher strength, lower permeability, shorter curing periods, better chemical resistances and a better durability is normally predicated, however this is a research...... field where published data are scarce. Durability and constantly high and good physical properties are some of the most important properties of the materials used in the building industry. Thermal durability, i.e. the ability of a material to retain its original physical-mechanical properties during and...

  1. Activity and Durability of Iridium Nanoparticles in the Oxygen Evolution Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Alia, Shaun M.; Rasimick, Brian; Ngo, Chilan; Neyerlin, Kenneth C.; Kocha, Shyam S.; Pylypenko, Svitlana; Xu, Hui; Pivovar, Bryan S.

    2016-07-15

    Unsupported iridium (Ir) nanoparticles, that serve as standard oxygen evolution reaction (OER) catalysts in acidic electrolyzers, were investigated for electrochemical performance and durability in rotating disk electrode (RDE) half-cells. Fixed potential holds and potential cycling were applied to probe the durability of Ir nanoparticles, and performance losses were found to be driven by particle growth (coarsening) at moderate potential (1.4 to 1.6 V) and Ir dissolution at higher potential (>/=1.8 V). Several different commercially available samples were evaluated and standardized conditions for performance comparison are reported. The electrocatalyst RDE results have also been compared to results obtained for performance and durability in electrolysis cells.

  2. RDS-21 Face-Gear Surface Durability Tests

    Science.gov (United States)

    Lewicki, David G.; Heath, Gregory F.; Filler, Robert R.; Slaughter, Stephen C.; Fetty, Jason

    2007-01-01

    Experimental fatigue tests were performed to determine the surface durability life of a face gear in mesh with a tapered spur involute pinion. Twenty-four sets of gears were tested at three load levels: 7200, 8185, and 9075 lb-in face gear torque, and 2190 to 3280 rpm face gear speed. The gears were carburized and ground, shot-peened and vibro-honed, and made from VIM-VAR Pyrowear 53 steel per AMS 6308. The tests produced 17 gear tooth spalling failures and 7 suspensions. For all the failed sets, spalling occurred on at least one tooth of all the pinions. In some cases, the spalling initiated a crack in the pinion teeth which progressed to tooth fracture. Also, spalling occurred on some face gear teeth. The AGMA endurance allowable stress for a tapered spur involute pinion in mesh with a face gear was determined to be 275 ksi for the material tested. For the application of a tapered spur involute pinion in mesh with a face gear, proper face gear shim controlled the desired gear tooth contact pattern while proper pinion shim was an effective way of adjusting backlash without severely affecting the contact pattern.

  3. [The problem of durable resistance of plants to different pests].

    Science.gov (United States)

    Odintsova, I G; Radchenko, E E; Tyryshkin, L G

    2002-01-01

    Different hypotheses concerning durable plant resistance against different pest were tested: 1) resistance is weak and polygenetically controlled; 2) resistance depends on "residual effect" of oligogenes that were overcome by pests. Contrast pair of plants and pests were used in experiments: wheat, barley--facultative parasite Bipolaris sorokiniana Shoem., wheat--obligate parasite Puccinia recondita Rob. ex Desm., sorghum--greenbug Schizaphis graminum Rond. Differential interaction between parasite and host plant resulted in their increased compatibility under long reproduction of parasite on resistant varieties were regarded as criteria of quick overcoming of resistance. The results did not support any hypothesis. The rate of adaptation of B. sorokiniana to the resistant varieties of wheat and barley did not depend on the level of resistance expression (weak, moderate or strong) and genetic control (oligogenic, polygenic or cytoplasmatic). It was shown by hybridological analysis that "residual effect" of oligogenes of sorghum resistance against greenbug depended on small resistance genes, that can be independent or weakly connected with marker oligogene. These data allows to doubt in phenomenon of "residual effect" of oligogenes. It was shown that non specific pathogenicity of parasitic fungi increased during their reproductions on sensitive varieties of plants. Thus, cultivation of sensitive varieties causes damage of crop culture non only because of their own losses, but also by increasing the infection of moderately resistant varieties. PMID:12070944

  4. New MEA Materials for Improved DMFC Performance, Durability and Cost

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, James H. [University of North Florida; Campbell, Joseph L. [University of North Florida; Cox, Philip [University of North Florida; Harrington, William J. [University of North Florida

    2013-09-16

    Abstract Project Title: New MEA Materials for Improved DMFC Performance, Durability and Cost The University of North Florida (UNF)--with project partners the University of Florida, Northeastern University, and Johnson Matthey--has recently completed the Department of Energy (DOE) project entitled “New MEA Materials for Improved DMFC Performance, Durability and Cost”. The primary objective of the project was to advance portable fuel cell MEA technology towards the commercial targets as laid out in the DOE R&D roadmap by developing a passive water recovery MEA (membrane electrode assembly). Developers at the University of North Florida identified water management components as an insurmountable barrier to achieving the required system size and weight necessary to achieve the energy density requirements of small portable power applications. UNF developed an innovative “passive water recovery” MEA for direct methanol fuel cells (DMFC) which provides a path to system simplification and optimization. The passive water recovery MEA incorporates a hydrophobic, porous, barrier layer within the cathode electrode, so that capillary pressure forces the water produced at the cathode through holes in the membrane and back to the anode. By directly transferring the water from the cathode to the anode, the balance of plant is very much simplified and the need for heavy, bulky water recovery components is eliminated. At the heart of the passive water recovery MEA is the UNF DM-1 membrane that utilizes a hydrocarbon structure to optimize performance in a DMFC system. The membrane has inherent performance advantages, such as a low methanol crossover (high overall efficiency), while maintaining a high proton conductivity (good electrochemical efficiency) when compared to perfluorinated sulfonic acid membranes such as Nafion. Critically, the membrane provides an extremely low electro-osmotic drag coefficient of approximately one water molecule per proton (versus the 2-3 for

  5. Durable solid oxide electrolysis cells for hydrogen production

    DEFF Research Database (Denmark)

    Sun, Xiufu; Chen, Ming; Hendriksen, Peter Vang;

    2014-01-01

    production is required for promoting commercialization of the SOEC technology. In this work, we report a recent 4400 hours test of a state-of-the-art Ni-YSZ electrode supported SOEC cell. The cell consists of a Ni-YSZ (YSZ: yttria stabilized zirconia) support and active fuel electrode, an YSZ electrolyte...... layer, a CGO (Gd doped ceria) inter-diffusion barrier layer and a LSCF-CGO (LSCF: lanthanum ferrite doped with strontium and cobalt) oxygen electrode layer. The electrolysis test was carried out at 800 °C under 1 A/cm2 with 90 % H2O + 10 % H2 supplied to Ni-YSZ electrode compartment. The results show...... cell increased during the durability test. Further analyses of the cell impedance show that both the LSCFCGO electrode and Ni-YSZ electrode degraded and the degradation was dominated by that of the Ni-YSZ electrode. Post-mortem analysis on the Ni-YSZ electrode revealed loss of percolation between Ni...

  6. Superhydrophobic durable coating based on UV-photoreactive silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nahum, T.; Dodiuk, H.; Dotan, A.; Kenig, S. [Department of Plastics Engineering, Shenkar College of Engineering and Design, 12 Anna Frank Street, Ramat Gan 52526 (Israel); Lellouche, J. P. [Department of Chemistry, Nanomaterials Research Center, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramar-Gan, 52900 (Israel)

    2015-05-22

    Superhydrophobic surfaces with contact angle (CA) >150 and sliding angle (SA) <10 have been aroused curiosity over the years due to their various applications. Superhydrophobicity can be obtained tailoring the chemistry and the roughness of the surface, mimicking the Lotus flower. Most superhydrophobic surfaces based on secondary bonding lose their roughness in harsh conditions and are unsuitable for practical applications. Photoreactive SiO{sub 2} nanoparticles (NPs) based on benzophenone (BP) can be a very effective tool for formation of reactive species that function as a molecular bridge by covalent bonding between the NP and any polymer matrix with C-C and C-H bonds. The present work focused on thermoset radiation curing urethane acrylate. Upon UV irradiation reactive excited nπ* triplet benzophenone species are formed and react through hydrogen abstraction to form ketyl radicals which interact with a radicals from the UV irradiated polymer matrix to yield covalent bonding. Roughness was achieved by dipping the substrate in SiO{sub 2}@BPs NPs dispersion followed by irradiation. Fluoroalkylsilane was used to obtain hydrophobic top layer. AFM nano manipulation was used to verify the immobilization of NPs. Evaluation of durability was made using air flow at 300 km/hr. Preliminary results indicate the formation of super hydrophobic surfaces (CA>150 and SA<10) with improved stability.

  7. Electro-active paper for a durable biomimetic actuator

    Science.gov (United States)

    Yun, Sung-Ryul; Yun, Gyu Young; Kim, Jung Hwan; Chen, Yi; Kim, Jaehwan

    2009-02-01

    Cellulose electro-active paper (EAPap), known as a smart material, has merits in terms of low voltage operation, light weight, dryness, low power consumption, biodegradability, abundance and low price. Since EAPap requires low power consumption, a remotely driven actuator has been proposed using microwave power transmission. This concept is attractive for many biomimetic systems such as crawling micro-insect robots, flying objects like dragon flies and smart wallpapers. However, the actuation performance of EAPap is sensitive to humidity and degrades with time. Thus, in this paper, a durable EAPap is studied. The fabrication of EAPap is explained and the actuation performance is shown with applied electric field, frequency, humidity level and time. The fabrication process includes dissolving cellulose fibers, eliminating solvent and Li ions with a mixture of deionized water and isopropyl alcohol, washing with water, drying and coating with gold. The morphology of the fabricated EAPap is analyzed by taking scanning electron microscope images and x-ray diffractograms. The actuation performance is tested in terms of bending displacement with frequency, time and humidity level

  8. Polyaniline: a conductive polymer coating for durable nanospray emitters

    Science.gov (United States)

    Maziarz; Lorenz; White; Wood

    2000-07-01

    Despite the tremendous sensitivity and lower sample requirements for nanospray vs. conventional electrospray, metallized nanospray emitters have suffered from one of two problems: low mechanical stability (leading to emitter failure) or lengthy, tedious production methods. Here, we describe a simple alternative to metallized tips using polyaniline (PANI), a synthetic polymer well known for its high conductivity, anticorrosion properties, antistatic properties, and mechanical stability. A simple method for coating borosilicate emitters (1.2 mm o.d.) pulled to fine tapers (4 +/- 1 microm) with water-soluble and xylene-soluble dispersions of conductive polyaniline (which allows for electrical contact at the emitter outlet) is described. The polyaniline-coated emitters show high durability and are resistant to electrical discharge, likely because of the thick (yet optically transparent) coatings; a single emitter can be used over a period of days for multiple samples with no visible indication of the destruction of the polyaniline coating. The optical transparency of the coating also allows the user to visualize the sample plug loaded into the emitter. Examples of nanospray using coatings of the water-soluble and xylene-soluble polyaniline dispersions are given. A comparison of PANI-coated and gold-coated nanospray emitters to conventional electrospray ionization (ESI) show that PANI-coated emitters provide similar enhanced sensitivity that gold-coated emitters exhibit vs. conventional ESI. PMID:10883822

  9. Durability issues for concrete in a deep geologic repository

    International Nuclear Information System (INIS)

    Concrete and cement-based materials are being considered in the design for sealing components in emplacement rooms, access tunnels, shafts and ramps and boreholes for deep geologic repositories. Cement-based materials are being considered as a grout material to isolate hydraulically active fractures and to fill interfaces between concrete and rock. Concrete may be used as a working surface floor in emplacement rooms and in access tunnels and as large structural seal components in composite seal systems. In some applications concrete may be used as a tunnel support in the form of shotcrete or rock bolt grout. Because of the potential for their wide use in various applications and locations, concrete and cement-based materials in a repository would experience different conditions at different times. These conditions would be related to the degree of saturation of the surrounding materials, the groundwater composition and movement, the rock type and character, and the extent of its exposure to either air or heat from containers. This paper reviews the potential mechanisms that could affect durability of concretes and grouts used in a repository. (author)

  10. Durability tests of a fiber optic corrosion sensor.

    Science.gov (United States)

    Wan, Kai Tai; Leung, Christopher K Y

    2012-01-01

    Steel corrosion is a major cause of degradation in reinforced concrete structures, and there is a need to develop cost-effective methods to detect the initiation of corrosion in such structures. This paper presents a low cost, easy to use fiber optic corrosion sensor for practical application. Thin iron film is deposited on the end surface of a cleaved optical fiber by sputtering. When light is sent into the fiber, most of it is reflected by the coating. If the surrounding environment is corrosive, the film is corroded and the intensity of the reflected signal drops significantly. In previous work, the sensing principle was verified by various experiments in laboratory and a packaging method was introduced. In this paper, the method of multiplexing several sensors by optical time domain reflectometer (OTDR) and optical splitter is introduced, together with the interpretation of OTDR results. The practical applicability of the proposed sensors is demonstrated in a three-year field trial with the sensors installed in an aggressive marine environment. The durability of the sensor against chemical degradation and physical degradation is also verified by accelerated life test and freeze-thaw cycling test, respectively. PMID:22737030

  11. Durability of incinerator ash waste encapsulated in modified sulfur cement

    International Nuclear Information System (INIS)

    Waste form stability under anticipated disposal conditions is an important consideration for ensuring continued isolation of contaminants from the accessible environment. Modified sulfur cement is a relatively new material and has only recently been applied as a binder for encapsulation of mixed wastes. Little data are available concerning its long-term durability. Therefore, a series of property evaluation tests for both binder and waste-binder combinations have been conducted to examine potential waste form performance under storage and disposal conditions. These tests include compressive strength, biodegradation, radiation stability, water immersion, thermal cycling, and leaching. Waste form compressive strength increased with ash waste loadings to 30.5 MPa at a maximum incinerator ash loading of 43 wt %. Biodegradation testing resulted in no visible microbial growth of either bacteria or fungi. Initial radiation stability testing did not reveal statistically significant deterioration in structural integrity. Results of 90 day water immersion tests were dependent on the type of ash tested. There were no statistically significant changes in compressive strength detected after completion of thermal cycle testing. Radionuclides from ash waste encapsulated in modified sulfur cement leached between 5 and 8 orders of magnitude slower than the leach index criterion established by the Nuclear Regulatory Commission (NRC) for low-level radioactive waste. Modified sulfur cement waste forms containing up to 43 wt % incinerator fly ash passed EPA Toxicity Characteristic Leaching Procedure (TCLP) criteria for lead and cadmium leachability. 11 refs., 2 figs., 5 tabs

  12. Durability of Polymeric Encapsulation Materials for Concentrating Photovoltaic Systems (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D. C.; Muller, M.; Kempe, M. D.; Araki, K.; Kennedy, C. E.; Kurtz, S. R.

    2012-03-01

    Many concentrating photovoltaic (CPV) systems use a polymeric encapsulant to couple and optical component and/or coverglass to the cell. In that location, the encapsulation improves the transmission of concentrated optical flux through interface(s), while protecting the cell from the environment. The durability of encapsulation materials, however, is not well established relative to the desired service life of 30 years. Therefore, we have initiated a screen test to identify the field-induced failure modes for a variety of popular PV encapsulation materials. An existing CPV module (with no PV cells present) was modified to accommodate encapsulation specimens. The module (where nominal concentration of solar flux is 500x for the domed-Fresnel design) has been mounted on a tracker in Golden, CO (elevation 1.79 km). Initial results are reported here for 18 months cumulative exposure, including the hottest and coldest months of the past year. Characteristics observed at intervals during that time include: visual appearance, direct and hemispherical transmittance, and mass. Degradation may be assessed from subsequent analysis (including yellowness index and cut-on frequency) relative to the ambient conditions present during field exposure. The fluorescence signature observed of all the silicone specimens is examined here, including possible factors of causation -- the platinum catalyst used in the addition cured materials as well as the primer used to promote adhesion to the quartz substrate and superstrate.

  13. Durability of geomembrane exposed to jet fuel A-1

    Energy Technology Data Exchange (ETDEWEB)

    Rimal, S.; Rowe, R.K.; Hansen, S. [Queen' s Univ., Kingston, ON (Canada). GeoEngineering Centre]|[Royal Military Coll. of Canada, Kingston, ON (Canada)

    2004-07-01

    A geosynthetic clay liner (GCL) has been installed at a former Canadian Distant Early Warning Line (DEW Line) site off the southeast coast of Baffin Island, in the Canadian Arctic. The liner was installed in an area of hydrocarbon contaminated soil to limit the migration of hydrocarbons to nearby water prior to future site remediation. This study examined the antioxidant depletion and the compatibility of both untreated and fluorinated high density polyethylene (HDPE) geomembranes with jet fuel A-1. The objective was to determine the durability and long term performance of the HDPE geomembrane. Geomembrane swatches were immersed in jet fuel and placed inside a fumehood at -23 degrees C. They were examined for changes in oxidative induction time, crystallinity, tensile properties and dimensions. Immersion in jet fuel appears to accelerate the antioxidant depletion rate compared to that observed in municipal solid waste leachate. The untreated geomembrane had a higher rate of antioxidant depletion than the fluorinated geomembrane, suggesting that fluorination is beneficial. Tensile tests show that immersion in jet fuel decreases the yield stress while increasing the strain at yield. The results indicate that there is no significant permeation by jet fuel or diffusion at lower temperatures for the short term, but additional studies are needed to confirm long term behaviour. 27 refs., 1 tab., 6 figs.

  14. Method Evaluating the Durability of Aircraft Piston Engines

    Directory of Open Access Journals (Sweden)

    Luca PIANCASTELLI

    2012-12-01

    Full Text Available A significant issue in aircraft engines is quantifying residual life to overhaul. The algorithm described in this paper calculates with a good level of reliability the residual life of a petrol piston engine. The method was tested on small, latest-generation, naturally-aspirated aircraft and racing piston engines, and has been effective in several experiments. This method is implemented directly on the electronic control system of the engine with very few lines of C-code. The method can also be used in many industrial engines. This innovative method assumes that only two main factors (power level and wear affect engine durability or time between overhauls. These two factors are considered as separate and combined with worst case criteria. The wear is assumed to follow a logarithmic law and a formula similar to the Miner’s law for material fatigue is used, making it possible to calculate the power-level curve with knowledge of only two points. The wear-curve is also related to elapsed engine cycles. The algorithm is very simple and can be implemented with just a few lines of software code accessing data collected from existing sensors. The system is currently used to evaluate actual residual life of racing engines.

  15. Marine durability of 23-year old reinforced concrete beams

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, T. U. [NEWJEC Inc., Technology Development Dept., Osaka (Japan); Otsuki, N. [Tokyo Inst. of Technology (Japan); Hisada, M. [Niigata Univ., (Japan); Hamada, H. [Ministry of Transport, Port and Harbor Research Inst., Yokosuka (Japan)

    2000-07-01

    Results of a study concerning the durability of 23-year old reinforced concrete beams exposed to marine tidal and atmospheric environments are presented. The study focused on the corrosion of steel bars with respect to orientation in concrete, carbonation and chloride ion-induced corrosion, quantitative evaluation of electrochemical data and the influence of stirrups on macrocell formation. Experimental work included half cell potential, polarization resistance, solution resistance investigations, chloride ion profile and carbonation depth measurements, microscopic observations of steel-concrete interfaces, and visual inspection of steel bars corrosion. Results showed that chloride ion-induced corrosion was significantly influenced by the orientation of the steel bars in the concrete. Macrocell corrosion was found to be the governing process of corrosion in atmospheric environment, while stirrups played an important role in macrocell formation. Assuming the use of a suitable pit concentration, polarization data was considered to provide an acceptable, although inexact, estimate of the depth of corrosion. Peak chloride ion concentration was not observed at the concrete surface but at some distance below the surface, probably due to the effect of wetting and drying cycles. 8 refs., 9 tabs., 11 figs.

  16. Durable strategies to deploy plant resistance in agricultural landscapes.

    Science.gov (United States)

    Fabre, Frédéric; Rousseau, Elsa; Mailleret, Ludovic; Moury, Benoit

    2012-03-01

    The deployment of resistant crops often leads to the emergence of resistance-breaking pathogens that suppress the yield benefit provided by the resistance. Here, we theoretically explored how farmers' main leverages (resistant cultivar choice, resistance deployment strategy, landscape planning and cultural practices) can be best combined to achieve resistance durability while minimizing yield losses as a result of plant viruses. Assuming a gene-for-gene type of interaction, virus epidemics are modelled in a landscape composed of a mosaic of resistant and susceptible fields, subjected to seasonality, and a reservoir hosting viruses year-round. The model links the genetic and the epidemiological processes, shaping at nested scales the demogenetic dynamics of viruses. The choice of the resistance gene (characterized by the equilibrium frequency of the resistance-breaking virus at mutation-selection balance in a susceptible plant) is the most influential leverage of action. Our results showed that optimal strategies of resistance deployment range from 'mixture' (where susceptible and resistant cultivars coexist) to 'pure' strategies (with only resistant cultivar) depending on the resistance characteristics and the epidemiological context (epidemic incidence and landscape connectivity). We demonstrate and discuss gaps concerning virus epidemiology across the agro-ecological interface that must be filled to achieve sustainable disease management. PMID:22260272

  17. Durable pd-based alloy and hydrogen generation membrane thereof

    Science.gov (United States)

    Benn, Raymond C.; Opalka, Susanne M.; Vanderspurt, Thomas Henry

    2010-02-02

    A durable Pd-based alloy is used for a H.sub.2-selective membrane in a hydrogen generator, as in the fuel processor of a fuel cell plant. The Pd-based alloy includes Cu as a binary element, and further includes "X", where "X" comprises at least one metal from group "M" that is BCC and acts to stabilize the .beta. BCC phase for stability during operating temperatures. The metal from group "M" is selected from the group consisting of Fe, Cr, Nb, Ta, V, Mo, and W, with Nb and Ta being most preferred. "X" may further comprise at least one metal from a group "N" that is non-BCC, preferably FCC, that enhances other properties of the membrane, such as ductility. The metal from group "N" is selected from the group consisting of Ag, Au, Re, Ru, Rh, Y, Ce, Ni, Ir, Pt, Co, La and In. The at. % of Pd in the binary Pd--Cu alloy ranges from about 35 at. % to about 55 at. %, and the at. % of "X" in the higher order alloy, based on said binary alloy, is in the range of about 1 at. % to about 15 at. %. The metals are selected according to a novel process.

  18. Durability Tests of a Fiber Optic Corrosion Sensor

    Directory of Open Access Journals (Sweden)

    Christopher K.Y. Leung

    2012-03-01

    Full Text Available Steel corrosion is a major cause of degradation in reinforced concrete structures, and there is a need to develop cost-effective methods to detect the initiation of corrosion in such structures. This paper presents a low cost, easy to use fiber optic corrosion sensor for practical application. Thin iron film is deposited on the end surface of a cleaved optical fiber by sputtering. When light is sent into the fiber, most of it is reflected by the coating. If the surrounding environment is corrosive, the film is corroded and the intensity of the reflected signal drops significantly. In previous work, the sensing principle was verified by various experiments in laboratory and a packaging method was introduced. In this paper, the method of multiplexing several sensors by optical time domain reflectometer (OTDR and optical splitter is introduced, together with the interpretation of OTDR results. The practical applicability of the proposed sensors is demonstrated in a three-year field trial with the sensors installed in an aggressive marine environment. The durability of the sensor against chemical degradation and physical degradation is also verified by accelerated life test and freeze-thaw cycling test, respectively.

  19. A durable and dependable solution for RTR spent fuel management

    International Nuclear Information System (INIS)

    RTR Operators need efficient and cost-effective services for the management of their spent fuel and this, for the full lifetime of their facility. Thanks to the integration of transport, reprocessing and conditioning services, COGEMA provides a cogent solution, with the utmost respect for safety and preservation of the environment, for the short, medium and long terms. As demonstrated in this paper, this option offers the only durable and dependable solution for the RTR spent fuel management, leading to a conditioning for the final residues directly suitable for final disposal. The main advantage of such an option is obviously the significant reduction in terms of volume and radiotoxicity of the ultimate waste when compared to direct disposal of spent fuels. The efficiency of such a solution has been proven, some RTR operators having already trusted COGEMA for the management of their aluminide fuel. With its commitment in R and D activities for the development of a high performance and reprocessable LEU fuels, COGEMA will be able to propose a solution for all types of fuels, HEU and LEU

  20. Durable development of tourism in Pitesti and Arges county

    Directory of Open Access Journals (Sweden)

    Bianca DABU

    2010-05-01

    Full Text Available Durable development is one of the main concerns of the contemporary period.The complex relationship between tourism, development and natural environment is anexample of the changes that have taken place in this filed of tourism considered animportant polluter of the natural environment. Tourism is the key element of durabledevelopment having an important impact on the economy, being considered a source ofeconomic growth. Romania has to find its way through the differences given by the needof development, the regulations imposed by the EU and the concerns related to the nextgenerations’ future. Tourism is an important component of the tertiary sector, aconsequence and interface branch of the national economy, and an industry withoutsmoke that has an important contribution to the creation of the world gross product. Anobjective of the National Development Plan adopted in December 2005, component ofthe National Economy Development Strategy is the capitalization of the tourist andcultural potential and the growth of these fields’ contribution to the regions’development, emphasizing the development of the infrastructure, diversifying andpromoting the internal touristy offer, the increase of competitiveness

  1. Preeclampsia prevention

    Directory of Open Access Journals (Sweden)

    Vitorino Modesto Santos

    2016-04-01

    Full Text Available Colombia and Brazil are developing countries where pregnancy-related hypertensive disorders and associated conditions constitute major concerns in public health area. Calcium plus conjugated linoleic acid used by pregnant adolescents had preventive effect on PE, but the prevention did not occur with utilization of calcium alone. After implementation of Colombian prenatal care program based on the bio-psychosocial model, maternal mortality and the rate of PE reduced in 23% and 22%, respectively. Late postpartum eclampsia, is the onset of seizuress more than 48 hours, but less than four weeks after delivery. This severe condition may occur without antecedent of PE. Lower maternal mortality due to preeclampsia/ eclampsia can follow implementation of prenatal programs based on BPSM, and use of calcium plus conjugated linoleic acid

  2. Durable Silver Mirror Coating Via Ion Assisted, Electron Beam Evaporation For Large Aperture Optics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In the Phase I research, Surface Optics Corporation (SOC) demonstrated a durable silver mirror coating based an ion assisted, thermal evaporation process. The...

  3. Retailer – Consumer Relationships for Durable Goods Market In Romania. A Multimethod Analysis

    Directory of Open Access Journals (Sweden)

    Manuela Rozalia Gabor

    2014-07-01

    Full Text Available The durable goods market in Romania has many features thanks to simultaneously: acquisition way, structure of households, retailers on this market, banking policies as regards providing consumption loans („loans with identity card only”, macroeconomic policies of tacit supporting in relation to banking policies etc. These characteristics are found in the low endowment with durable goods of households in Romania, and that generate features of the acquisition process, the decision taking process of durable goods and implicitly of retailer – consumer relationships. This paper covers the last aspect, being used a representative urban sample of 300 households, the following methods being used for data processing: 2test bivariate, ANOVA, Wilcoxon test, Cronbach alpha, split – half, the goal of this paper being that to provide new results referring to retailer – consumer relationships for the durable goods market in Romania, that confirm or infirm the foreign research results..

  4. Next Generation , Lightweight, Durable Boot Materials to Provide Active & Passive Thermal Protection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this NASA Phase I SBIR program is to leverage lightweight, durable materials developed by NanoSonic for use within extra vehicular activity (EVA)...

  5. Recent Advances in Durability and Damage Tolerance Methodology at NASA Langley Research Center

    Science.gov (United States)

    Ransom, J. B.; Glaessgen, E. H.; Raju, I. S.; Harris, C. E.

    2007-01-01

    Durability and damage tolerance (D&DT) issues are critical to the development of lighter, safer and more efficient aerospace vehicles. Durability is largely an economic life-cycle design consideration whereas damage tolerance directly addresses the structural airworthiness (safety) of the vehicle. Both D&DT methodologies must address the deleterious effects of changes in material properties and the initiation and growth of damage that may occur during the vehicle s service lifetime. The result of unanticipated D&DT response is often manifested in the form of catastrophic and potentially fatal accidents. As such, durability and damage tolerance requirements must be rigorously addressed for commercial transport aircraft and NASA spacecraft systems. This paper presents an overview of the recent and planned future research in durability and damage tolerance analytical and experimental methods for both metallic and composite aerospace structures at NASA Langley Research Center (LaRC).

  6. Extremely durable biofouling-resistant metallic surfaces based on electrodeposited nanoporous tungstite films on steel

    Science.gov (United States)

    Tesler, Alexander B.; Kim, Philseok; Kolle, Stefan; Howell, Caitlin; Ahanotu, Onye; Aizenberg, Joanna

    2015-10-01

    Formation of unwanted deposits on steels during their interaction with liquids is an inherent problem that often leads to corrosion, biofouling and results in reduction in durability and function. Here we report a new route to form anti-fouling steel surfaces by electrodeposition of nanoporous tungsten oxide (TO) films. TO-modified steels are as mechanically durable as bare steel and highly tolerant to compressive and tensile stresses due to chemical bonding to the substrate and island-like morphology. When inherently superhydrophilic TO coatings are converted to superhydrophobic, they remain non-wetting even after impingement with yttria-stabilized-zirconia particles, or exposure to ultraviolet light and extreme temperatures. Upon lubrication, these surfaces display omniphobicity against highly contaminating media retaining hitherto unseen mechanical durability. To illustrate the applicability of such a durable coating in biofouling conditions, we modified naval construction steels and surgical instruments and demonstrated significantly reduced marine algal film adhesion, Escherichia coli attachment and blood staining.

  7. Optimal Monetary Policy with Durable Consumption Goods and Factor Demand Linkages

    DEFF Research Database (Denmark)

    Petrella, Ivan; Santoro, Emiliano

    -durable spending in response to a monetary policy shock. A main result of our monetary policy analysis is that strategic complementarities generated by factor demand linkages amplify social welfare loss. As the degree of interconnection between sectors increases, the cost of misperceiving the correct production......This paper deals with the implications of factor demand linkages for monetary policy design. We develop a dynamic general equilibrium model with two sectors that produce durable and non-durable goods, respectively. Part of the output produced in each sector is used as an intermediate input...... technology of each sector can rise substantially. In addition, the transmission of different sources of exogenous perturbation is altered, compared to what is commonly observed in standard two-sector models without factor demand linkages. In this respect, the role of the relative price of non-durable goods...

  8. Farmers' participation and breeding for durable disease resistance in the Andean region

    NARCIS (Netherlands)

    Danial, D.L.; Parlevliet, J.E.; Almekinders, C.J.M.; Thiele, G.

    2007-01-01

    In the Andean region, the Preduza project and its partners combined breeding for durable disease resistance using locally adapted cultivars and farmer participatory methods. The approach taken resembles participatory variety selection (PVS). Farmers participated in the selection of advanced material

  9. Cholera Prevention and Control

    Science.gov (United States)

    ... name="commit" type="submit" value="Submit" /> Prevention & Control Recommend on Facebook Tweet Share Compartir Prevention of ... of cholera and other diarrheal disease prevention. Prevention Control Topics Five Basic Cholera Prevention Messages I nfection ...

  10. Durable Pulmonary Vein Isolation: The Holy Grail of Atrial Fibrillation Ablation

    Directory of Open Access Journals (Sweden)

    Duy Thai Nguyen; William H. Sauer

    2010-10-01

    Full Text Available The inability to achieve durable pulmonary vein isolation remains a major limitation to catheter ablation for the treatment of atrial fibrillation (AF. In this review, we discuss the research performed over the past decade investigating methods to improve lesion permanence for the goal of durable pulmonary vein isolation (PVI. Investigations evaluating procedural techniques, adjunctive pharmacologic therapy, and newer energy sources designed to improve ablation lesion permanence are discussed.

  11. Do Migrant Remittances Affect Household Purchases of Physical Investments and Durable Goods? Evidence for Kenya

    OpenAIRE

    Farai Jena

    2015-01-01

    This paper investigates the impact of remittances on household decisions to purchase physical investments and durable goods in Kenya using household survey data. Remittances are found to be endogenous in the durable goods case and their effects are estimated using bivariate and IV probit models. In the physical investments case, remittances are found to be exogenous and remittance effects are estimated using univariate probit models. The evidence obtained is supportive of remittances having a...

  12. Effect of Fly Ash on Durability of High Performance Concrete Composites

    OpenAIRE

    Peng Zhang; Qingfu Li

    2013-01-01

    A parametric experimental study has been conducted to investigate the effect of fly ash on the durability of the concrete composites. Four different fly ash contents (10, 15, 20 and 25% respectively) were used. The durability of concrete composites includes water impermeability, dry shrinkage property, the carbonation resistance and the freeze-thaw resistance. The results indicate that the addition of fly ash has greatly improved the water impermeability and restricted the dry shrinkage of co...

  13. Durability Evaluation in Concrete Using Cracked Permeability and Chloride Permeability Tests

    OpenAIRE

    V. M. Sounthararajan; A. Sivakumar

    2013-01-01

    The objective of this study is to identify the possibilities of utilizing the quarry dust in concrete to obtain an improved strength and durability properties of concrete. In the present study, the addition of quarry dust as alternative for natural sand has been investigated, and the durability properties of concrete were evaluated systematically by means of cracked water permeability and rapid chloride permeability tests. The permeability of concrete was assessed with initial stress applied ...

  14. Fostering a durable relationship between a waste management facility and its host community

    International Nuclear Information System (INIS)

    Any long-term radioactive waste management project is likely to last decades to centuries. It requires a physical site and will impact in a variety of ways on the surrounding community over that whole period. The societal durability of an agreed solution is essential to success. This report identifies a number of design elements (including functional, cultural and physical features) that favour a durable relationship between the facility and its host community by improving prospects for quality of life across generations

  15. Aligned carbon nanotube based ultrasonic microtransducers for durability monitoring in civil engineering

    OpenAIRE

    LEBENTAL, Bérengère; Chainais, Pierre; CHENEVIER, Pascale; Chevalier, Nicolas; Delevoye, Eric; Fabbri, Jean-Marc; Nicoletti, Sergio; Renaux, Philippe; Ghis, Anne

    2011-01-01

    International audience Structural health monitoring of porous materials such as concrete is becoming a major component in our resource-limited economy, as it conditions durable exploitation of existing facilities. Durability in porous materials depends on nanoscale features which need to be monitored in situ with nanometric resolution. To address this problem, we put forward an approach based on the development of a new nanosensor, namely a capacitive micrometric ultrasonic transducer whos...

  16. Commitment Power in a Non-Stationary Durable-Good Market

    OpenAIRE

    Usategui Díaz de Otalora, José María

    2001-01-01

    This paper derives and evaluates the decisions of a durable good monopolist in a context where demand for the services of the durable good changes over time. It shows that, if the size of the market decreases over time, social welfare may be higher when the monopolist has commitment ability than when she has not. Moreover, the equilibrium under a monopolist seller with commitment power may Pareto-dominate the equilibrium under a monopolist seller without commitment ability. The work also prov...

  17. Durability design of concrete structures, Part 2: Modelling and structural assessment

    OpenAIRE

    Folić Radomir; Zenunović Damir

    2010-01-01

    This paper is a sequel to [19] where the theoretical foundations were given for the analysis of durability of concrete structures. An overview of some approaches to modeling the durability of RC structures is given in the paper. Experiences resulting from experimental and numerical research of some influential parameters leading to corrosion of the reinforcement, cracks and delaminating of the surrounding concrete, which leads to the decrease of service life of the RC structure's elements, ar...

  18. Probability-based durability design of concrete structures in marine environment

    OpenAIRE

    Ferreira, Rui Miguel, ed. lit.; Jalali, Said

    2006-01-01

    In recent years, much research work has been carried out in order to obtain a more controlled durability and long-term performance of concrete structures in chloride containing environments. In particular, the development of new procedures for probability-based durability design has been shown to provide a more realistic basis for the analysis. Although relevant data is still lacking, this approach has been successfully applied to several new concrete structures, where requirement...

  19. Durability performance of concrete bridge piers made with metakaolin and latex mixes

    OpenAIRE

    Camões, Aires; Cruz, Paulo J.S.; Jalali, Said; Ferreira, Rui Miguel, ed. lit.; Cunha, P. J.

    2004-01-01

    Requirements for assessment of structural performance based on a combination of concrete strength and reinforcement cover seems to be insufficient to provide adequate durability of reinforced and prestressed concrete structures. Under these circumstances, the construction industry is expected to generalize the use of higher quality concrete with an enhanced or even high performance. This paper summarizes the main results of several tests to assess the durability performance of dif...

  20. Research on Concrete Durability Improving for Existing Island-Building and Its Application

    OpenAIRE

    Jianghong, Mao; Yaofeng, Zhu; Fangyuan, Xu; Weiliang, Jin; Yidong, Xu; Xu, Chen

    2016-01-01

    China’s coastal cities contain a large number of islands with abundant human activities, in which buildings are in a typical marine corrosion environment and the corrosion of reinforced concrete structures is very prominent. This paper makes research work on two aspects: (1) the durability assessment and durability improvement after a thorough investigation of the architecture of Xiangtan County, Ningbo city, on an island and (2) the application research of the bidirectional electromigration ...

  1. Lime-based repair mortars with water-repellent admixtures: laboratory durability assessment

    OpenAIRE

    Nunes, C.; Slížková, Z. (Zuzana)

    2015-01-01

    Conservation of architectural structures using lime binders is currently an important research topic aiming compatibility, durability and sustainability. In this study, lime (L) and lime-metakaolin (LM) mortars were prepared with the addition of water-repellent admixtures: linseed oil, stand oil and a silane based water-repellent. Experimental results demonstrate that oil imparts higher hydrophobicity to both L and LM mixtures. Durability was assessed through freeze-thaw and NaCl crystal...

  2. Various durability aspects of calcined Kaolin-blended Portland cement pastes and concretes

    OpenAIRE

    SAILLIO, Mickael; BAROGHEL BOUNY, Véronique; PRADELLE, Sylvain

    2015-01-01

    The use of calcined clay, in the form of metakaolin (MK), as a pozzolanic constituent for concrete has received considerable attention in recent years, due to the lower CO2 emission of this supplementary cementitious material compared to the production of a classic portland cement. Furthermore, concretes incorporating MK show some improve durability properties. In this paper, the durability of concretes and cement pastes with MK as partial replacement of cement (10 and 25%) has been investiga...

  3. Various durability aspects of cement pastes and concretes with supplementary cementitious materials

    OpenAIRE

    SAILLIO, Mickael; BAROGHEL BOUNY, Véronique; PRADELLE, Sylvain

    2016-01-01

    The use of supplementary cementitious materials (SCMs) as a constituent for concrete receives considerable attention, due to the lower CO2 emission of these materials compared to the production of classic Portland cement. Furthermore, concretes incorporating SCMs show some improved durability properties. SCMs are mainly pozzolanic materials (Fly Ash or Metakaolin) or alkali-activated materials such as ground granulated blast slag (GGBS). In this paper, the durability of concretes and cement p...

  4. Planned obsolescence: Understanding the reality of durable goods obsolescence and consumers' disposal behaviour

    OpenAIRE

    Nejedlá, Jana

    2010-01-01

    Planned obsolescence is the term used to describe incentives of companies to make durable goods faster obsolete. The aim of the study is to make a big picture and real situation about planned obsolescence practising and consumer disposal behaviour. First part addresses the theoretical background and provides comprehensive overview through different aspects of the good's durability issue and planned obsolescence characteristics and influences. Second part in further reference to the informatio...

  5. Laboratory aging of asphalt mixtures : simulation of reclaimed asphalt and application as test method for durability

    OpenAIRE

    Mollenhauer, Konrad; MOUILLET, Virginie; PIERARD, Nathalie; TUSAR, Marjan; Gabet, Thomas

    2012-01-01

    Surface asphalt courses reach their end of service life after a time span between 10 and 30 years, depending on their durability. Afterwards, the surface layer is usually milled and reused in asphalt mixtures as reclaimed asphalt. In order to enable the analysis of durability and recyclability of a new asphalt mixture, four laboratory aging procedures were designed and comparatively applied on twoasphalt mixes. Besides aging of loose asphalt mix in heating cabinets at varied temperatures and ...

  6. Durable Pulmonary Vein Isolation: The Holy Grail of Atrial Fibrillation Ablation

    Directory of Open Access Journals (Sweden)

    Darrat Y; Morales G; Shah J; Di Biase L; Natale A; Elayi CS

    2014-04-01

    Full Text Available The inability to achieve durable pulmonary vein isolation (PVI remains a major limitation to catheter ablation for the treatment of atrial fibrillation (AF, potentially resulting in AF recurrence. In this review, we discuss the research performed investigating methods to improve lesion permanence for the goal of durable PVI. Investigations evaluating procedural techniques, various catheters utilized, adjunctive pharmacologic therapy, and novel energy sources designed to improve ablation lesion permanence are discussed.

  7. Influence of the mineral admixture on the durability of medium-strenght self compacting concrete

    OpenAIRE

    Bermejo Núñez, Ester B.; Gálvez Ruíz, Jaime; Fernández Cánovas, Manuel; Moragues Terrades, Amparo

    2010-01-01

    Self-compacting concrete (SCC) is an innovative concrete that does not require vibration for placing and compacting. SCC, developed in Japan in the 1980s, provides a present-day and attractive challenge for many researchers, as the long list of papers on the topic corroborates. Nevertheless, the durability of SCC, especially medium strength SCC, provides the researcher with opportunities for study in depth. This paper deals with the durability of SCC: two SCC mixtures, with 30 MPa com...

  8. Old materials and techniques to improve the durability of earth buildings

    OpenAIRE

    Camões, Aires; Eires, R.; Jalali, Said

    2012-01-01

    Quite a big part of the world’s heritage is still made by earth constructions. The durability of the existent heritage, as well as the new earth buildings is particularly conditioned by erosion caused by water action, especially in countries with high rainfall index. With this research one intends to value the ancient knowledge in order to allow higher durability. Analysing the old building techniques to protect the earth material from the water action it is possible to understand how ear...

  9. Stress load and durability analysis of railway vehicles using multibody approach

    Directory of Open Access Journals (Sweden)

    Nikolay LYSIKOV

    2007-01-01

    Full Text Available The present paper describes the CAE-based approach for durability analysis that is being implemented in Universal Mechanism software to predict the fatigue damage of parts of mechanical systems. The approach predicts fatigue strength of structural components of machines and mechanisms based on results of simulating their dynamics taking into account real working conditions. An application to the developedsoftware to a stress load and durability analysis is considered.

  10. Highly Durable and Active PtFe Nanocatalyst for Electrochemical Oxygen Reduction Reaction.

    Science.gov (United States)

    Chung, Dong Young; Jun, Samuel Woojoo; Yoon, Gabin; Kwon, Soon Gu; Shin, Dong Yun; Seo, Pilseon; Yoo, Ji Mun; Shin, Heejong; Chung, Young-Hoon; Kim, Hyunjoong; Mun, Bongjin Simon; Lee, Kug-Seung; Lee, Nam-Suk; Yoo, Sung Jong; Lim, Dong-Hee; Kang, Kisuk; Sung, Yung-Eun; Hyeon, Taeghwan

    2015-12-16

    Demand on the practical synthetic approach to the high performance electrocatalyst is rapidly increasing for fuel cell commercialization. Here we present a synthesis of highly durable and active intermetallic ordered face-centered tetragonal (fct)-PtFe nanoparticles (NPs) coated with a "dual purpose" N-doped carbon shell. Ordered fct-PtFe NPs with the size of only a few nanometers are obtained by thermal annealing of polydopamine-coated PtFe NPs, and the N-doped carbon shell that is in situ formed from dopamine coating could effectively prevent the coalescence of NPs. This carbon shell also protects the NPs from detachment and agglomeration as well as dissolution throughout the harsh fuel cell operating conditions. By controlling the thickness of the shell below 1 nm, we achieved excellent protection of the NPs as well as high catalytic activity, as the thin carbon shell is highly permeable for the reactant molecules. Our ordered fct-PtFe/C nanocatalyst coated with an N-doped carbon shell shows 11.4 times-higher mass activity and 10.5 times-higher specific activity than commercial Pt/C catalyst. Moreover, we accomplished the long-term stability in membrane electrode assembly (MEA) for 100 h without significant activity loss. From in situ XANES, EDS, and first-principles calculations, we confirmed that an ordered fct-PtFe structure is critical for the long-term stability of our nanocatalyst. This strategy utilizing an N-doped carbon shell for obtaining a small ordered-fct PtFe nanocatalyst as well as protecting the catalyst during fuel cell cycling is expected to open a new simple and effective route for the commercialization of fuel cells. PMID:26670103

  11. Enhanced washing durability of hydrophobic coating on cellulose fabric using polycarboxylic acids

    International Nuclear Information System (INIS)

    Nine polycarboxylic acids were used to improve washing durability of hydrophobic cellulose fabric finished by sol-gel method. By simultaneous forming ester-bridge between cellulose and silica layer by ester bond, polycarboxylic acids could anchor silica coating onto cellulose fabric to strengthen the adhesion of organic-inorganic hybrid coating. The wettability of treated fabrics was characterized by water contact angle, spray test and hydrostatic pressure test. The results showed that all investigated polycarboxylic acids could improve the durability. The polycarboxylic acid with proper distance between terminal carboxylic acid groups and number of carboxylic acid groups showed the highest durability. 1,2,3,4-butanetetracarboxylic acid (BTCA) led to the best durability of hydrophobic cellulose fabric with water contact angle of 137.6o (recovery percentage of 94.2%) after 30 washing times. The effect of BTCA on durability was characterized by scanning electron microscopy. This study demonstrated that the surface treatment using polycarboxylic acids and mixed organosilanes is a promising alternative for achieving durable hydrophobic fabrics.

  12. Correlation between texture and mechanical stress durability of thin aluminum films

    International Nuclear Information System (INIS)

    In this article, differently textured aluminum (Al) metallizations of surface acoustic wave (SAW) devices have been exposed to cyclic mechanical stress in order to investigate a potential correlation between their texture and their mechanical stress durability. Samples of SAW devices with differently textured Al thin film electrodes have been manufactured, and texture measurements have been carried out on all samples with electron backscatter diffraction. Subsequently, the SAW devices have been operated at heavy electrical load until a defined mechanical fatigue of its Al electrodes occurred. SAW devices with highly textured Al electrodes showed almost 20 times higher power durability than SAW devices with untextured Al electrodes. We show that this increase in electrical power durability has to be fully attributed to the strongly enhanced mechanical stress durability of highly textured Al films. Furthermore, a positive correlation between the Al films' texture and its electrical conductivity has been found. - Highlights: • We show highly textured growth of thin Al films on a clean, monocrystalline LiTaO3 • Highly textured Al growth gets disturbed by prior photolithographic process steps • Power durability of a SAW device increases with texture of its metallization • Texture and mechanical stress durability of a thin Al film are tightly correlated

  13. Durability of Selected Membrane Materials when Exposed to Chlorine Gas

    Energy Technology Data Exchange (ETDEWEB)

    Eikeland, Marianne Soerflaten

    2001-03-01

    This thesis is focusing on the durability of selected membrane materials when exposed to chlorine gas in the temperature range 30-100{sup o}C. Studies of the changes of membrane separation properties and the mechanisms promoting these changes have been studied. The selected membrane materials were poly(dimethylsioxane) (PDMS), Fluorel, fluorosilicone, and blends of PDMS and Fluorel. The thesis is organised in seven chapters. The first chapter gives an introduction to the background of the work. The second chapter presents the theory for gas separation using dense rubbery membranes. The properties of the selected membrane materials are presented in chapter three. The fourth chapter describes degradation mechanisms for polymeric materials in general and for the selected membrane materials in particular. Presentation of the experimental work is given in chapter five, while the results with discussions are presented in chapter six. The conclusions and recommendations for further studies are given in chapter seven. Five appendixes are attached: Appendix A describes the calculations of permeability and solubility coefficients and the accuracy of the experimental measurements. Appendix B summarises the measured values in tables and Appendix C describes the analytical methods. Appendix D gives the properties of the gases used in the experiments. Appendix E is the article ''Durability of Poly(dimethylsiloxane) when Exposed to Chlorine Gas'', submitted to the Journal of Applied Polymer Science. Highly crosslinked PDMS was found to have an initial high permeability for chlorine gas and a high Cl{sub 2}/O{sub 2} selectivity. However when exposed to chlorine gas the permeability decreased significantly. Crosslinking of the PDMS polymer chain and chlorination of the polymer gave a denser polymer structure and thus lower permeability. Fluorel showed very low permeabilities and selectivities for the gases in question and was thus not interesting for this

  14. Territoires ruraux insulaires et développement durable

    Directory of Open Access Journals (Sweden)

    Laurent Rieutort

    2009-05-01

    Full Text Available Après avoir rappelé que comme concept de gestion des territoires, le développement durable peut s’inscrire dans un système territorial complexe, l’article s’interroge sur les imaginaires associés à la ruralité et à l’insularité. Largement issue du regard de nos sociétés urbaines, la critique des abus d’un modèle de développement insulaire peu respectueux d’un environnement détérioré et/ou à l’abandon, conduit à promouvoir une gestion des territoires intégrant également une dimension économique et socioculturelle, notamment un fort mouvement de « patrimonialisation », sorte de réinvention de l’île mythique, symbole d’un équilibre passé. Divers exemples (île grecque de Skopelos, Corse, Martinique montrent que ressources et savoir-faire spécifiques, difficilement transposables en dehors du contexte insulaire, peuvent être considérés comme un atout pour le développement ; ils renforcent l’identité d’une communauté et inspirent des dynamiques sociales renouvelées. Pour autant, il importe de réfléchir aux interactions entre des filières qui partagent les mêmes lieux, les mêmes ressources et impliquent les mêmes personnes. A l’évidence, la qualité du lien social augmente la résilience du système territorial même si cela passe par une redéfinition des règles collectives qui visent à inventer des solidarités durables passant davantage par des savoir-être ensemble que par des savoir-faire purement techniques.As a concept of territorial management, sustainable development can be analysed in the systemic vision allowed by complex territorial systems. This article wonders about the representations associated to rural areas and insularity. Largely encouraged by our modern societies, the critical vision of island development – not environmentally friendly models – promotes an integrated vision of development aiming at combining economical and sociocultural considerations. The

  15. Performance and Durability Evaluation of Bamboo Reinforced Cement Concrete Beams

    Directory of Open Access Journals (Sweden)

    Ankit Singh Mehra

    2016-04-01

    Full Text Available A big part of population in India is still homeless due to raising unaffordability of housing structures. People sleeping on roadsides and living in slums is a common sight in Indian cities. To overcome this problem India today needs millions of houses for their growing population, making concrete as the most widely to be used material in the country. Concrete has found to have excellent compressive strength but poor in tensile strength, to take care of the tensile stresses steel is commonly used as reinforcing material in concrete. Production of steel is a very costly business and its use in concrete as reinforcing material increases the cost of construction by many folds. Also production of steel emits a large amount of green house gases causing considerable deterioration of the environment. The above mentioned socio-economic and environmental factors creates a necessity for finding an appropriate environment friendly and cheap material that can successfully substitute steel as reinforcement in concrete elements of a low cost dwelling for the poor and homeless people of the country. It is here that engineered bamboo can be of great value to Civil Engineers owning to its several net worthy features. Production of every tone of bamboo consumes about a tone of atmospheric CO2 in addition to releasing fresh O2. From structural point of view bamboo has been used as a structural material from the earlier times as it possesses excellent flexure and tensile strength as well as high strength to weight ratio. All this necessitates examining bamboo-reinforced cement concrete in detail for its appropriateness as a structural material for construction of a low cost dwelling unit. The study focuses on evaluating the mechanical and durability properties of cement-concrete beams both singly and doubly reinforced with bamboo splints.

  16. Factors determining the durability of steam superheater chambers

    Directory of Open Access Journals (Sweden)

    J. Lisok

    2008-11-01

    Full Text Available Purpose: The paper presents the results of calculations of effort for the material of selected superheater chambers’constructional systems in unsteady operation conditions.Design/methodology/approach: In model tests, the influence was analysed of internal pressure andtemperature gradient in the chamber wall on the distribution and value of stress . In the calculations, the processof hot start-up of a boiler was simulated, which was accompanied by short thermal shock induced by rapid coolingof the chamber inner wall.Findings: The random nature of thermal shock, which in the industrial practice may occur in any row and to anynumber of coil pipes, determines the value of maximal stress and the area of its occurrence. It has a significantinfluence on the possibility of forecasting the durability of chambers in working conditions.Research limitations/implications: The research has evidenced a link between the method of forcingthermal shock and the value of maximal stress in the area of bridges.Practical implications: The research has demonstrated the existence of connection between the way of forcingthermal shock and the stress value which, depending on the variant of cooling the chamber, ranges between150-370 MPa. These results are very important to the industry connected with the structure of pipelines.Originality/value: It was found that the primary reason for the superheater chamber damage, leading to crackformation, are thermal shocks. A link has been shown between the method of forcing the thermal shock and thevalue of maximal stress in the zone of bridges.

  17. Evaluating the durability of a simulated nuclear waste glass

    International Nuclear Information System (INIS)

    Multicomponent systems tests of the durability of fuel recycle waste glass are an important tool to assess the long-term performance of a nuclear waste isolation system. A fractional factorial design was chosen for these test, with three parameters: the cation exchange capacity of clay, the ionic strength of groundwater, and the concentration of clay in groundwater. The dissolution behaviour of a simulated nuclear waste form based on sodium borosilicate glass was investigated at these three levels. The normalised leach rates at 90 degrees Celcius based on boron release were 9.5 x 10-9 kg/(m2.s) in contact with Ca-montmorillonite, 4.3 x 10-9 kg/(m2.s) in contact with No-montmorillonite, 2.8 x 10-9 kg/(m2.s) in contact with illite, and 1.1 x 10-9 kg/(m2.s) in contact with a No-montmorillonite/illite mixture (1:1). The average leach rates at 90 degrees Celcius based on the mass loss of glass were 6.1 x 10-9 kg/(m2.s) in contact with Ca-montmorillonite, 6.0 x 10-9 kg/(m2.s) in contact with illite, 4.7 x 10-9 kg/(m2.s) in contact with a No-montmorillonite/illite mixture (1:1), and 2.0 x 10-9 kg/(m2.s) in contact with No-montmorillonite. The clay/groundwater ratio was found to have only a minor effect on glass dissolution under the experimental conditions chosen. 38 refs

  18. Durable resistance to Puccinia triticina by accumulation of resistance genes

    Directory of Open Access Journals (Sweden)

    Bošković Jelena

    2009-01-01

    Full Text Available The individual use of single race-specific resistance genes with major phenotypic effects has rarely provided lasting resistance. However, breeding and combining or pyramiding of resistance genes into individual cultivars has had considerable success, particularly in situations in which the pathogen does not reproduce sexually, as in the case of wheat leaf rust pathogen. In European-Mediterranean region perfomed international investigations of wheat leaf rust proved that breeding of new lines of wheat resistant to Puccinia triticina Eriks. for differentiation of pathogen population, as well as for sources of durable resistance is necessary. Breeding of such resistant lines has proved necessary due to the unsatisfatory survey results of these regions on standard isogenic Lr lines. It has become clear that these regions needed new, more efficient differential resistance genes, as well as sources of resistance. In the beginning, after extensive screening tests of several International Rust Nurseries, 18 donors of resistance had been selected as crosses with recurrent parents' varieties Princ and Starke. These hybrid lines had been comparatively tested with twenty six Lr single gene lines using twenty especially virulent cultures of P. triticina in order to check the presence of these known Lr genes in our hybrid lines. Considerable influence of recurrent parent to the number of resistant genes in used donors was demonstrated. On the other hand, considerable influence of the pathogen culture was established to the number of resistance genes in used donors. In order to enhance resistance and pyramiding genes in these hybrids, the most interesting selected eight lines have been crossed with only effective isogenic ones, containing the strong genes Lr9, Lr19 and Lr24. On the basis of different segregation rations of all crossing combinations it was proved that no one of resistant donors contained the applied strong resistant genes. It means that our

  19. Thermal durability of modified Synroc material as reactor fuel matrix

    International Nuclear Information System (INIS)

    A Synroc, a polyphase titanate ceramics composed of three mineral phases (perovskite, hollandite and zirconolite), has an excellent performance of immobilization of high level nuclear waste. A working group in the Department of Hot Laboratories paid special attention to this merit and started a development study on a LWR fuel named 'Waste Disposal Possible (WDP) Fuel', which has the two functions of a reactor fuel and a waste form. The present paper mainly describes thermal durability of a modified Synroc material, which is essentially important for applying the material to a fuel matrix. The two kinds of Synroc specimens, designated 'SM' as modified and 'SB' as a reference, were prepared by hot-pressing and annealed at 1200degC to 1500degC for 30 min in air. Unexpected and peculiar spherical voids were observed in the specimen SM at 1400degC and 1500degC, which caused the specimen swelling. The formation of the voids depends significantly on the existence of spherical precipitates seen in the as-fabricated specimen including latent micropores with high pressure. On the other hand, the heat treatment at 1500degC formed additional new phases, designated 'Phase A' for the specimen SB and 'Phase X' for SM. Phase A is a decomposition product of hollandite and Phase X a reaction product of Phase A and perovskite in the spherical voids. Furthermore, additional information and thermal properties examined are presented in Appendix 1 and Appendix 2, respectively. It was recognized that the modified Synroc specimen SM had excellent thermal properties. (author)

  20. Study on durability for thermal cycle of planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Motoo; Nakata, Kei-ichi; Wakayama, Sin-ichi [Tonen Corp., Saitama (Japan)] [and others

    1996-12-31

    TONEN CORPORATION has developed planar type SOFC since 1986. We demonstrated the output of 1.3 kW in 1991 and 5.1 kW in 1995. Simultaneously we have studied how to raise electric efficiency and reliability utilizing hydrogen and propane as fuel. Durability for thermal cycle is one of the most important problems of planar SOFC to make it more practical. The planar type SOFC is made up of separator, zirconia electrolyte and glass sealant. The thermal expansion of these components are expected to be the same value, however, they still possess small differences. In this situation, a thermal cycle causes a thermal stress due to the difference of the cell components and is often followed by a rupture in cell components, therefore, the analysis of the thermal stress should give us much useful information. The thermal cycle process consists of a heating up and cooling down procedure. Zirconia electrolyte is not bonded to the separator under the condition of the initial heating up procedure, and glass sealant becomes soft or melts and glass seals spaces between the zirconia and separator. The glass sealant becomes harder with the cooling down procedure. Moreover, zirconia is tightly bonded with separator below a temperature which is defined as a constraint temperature and thermal stress also occurs. This indicates that the heating up process relaxes the thermal stress and the cooling down increases it. In this paper, we simulated dependence of the stress on the sealing configuration, thermal expansion of sealant and constraint temperature of sealant glass. Furthermore, we presented SOFC electrical properties after a thermal cycle.

  1. Durability of Peace Education Effects in the Shadow of Conflict

    Science.gov (United States)

    Rosen, Yigal; Salomon, Gavriel

    2011-01-01

    Value-oriented instructional programs, such as anti-racism, may often face societal barriers. A case in point are peace education programs in conflictual contexts. Close analysis of peace education programs in regions of conflict and tension suggest that they face formidable barriers that would appear to prevent the attainment of their goals of…

  2. A glass durability model based on understanding glass chemistry and structural configurations of the glass constituents

    International Nuclear Information System (INIS)

    An improved structural bond strength (SBS) model has been developed to quantify the correlation between glass compositions and their chemical durabilities. The SBS model assumes that the strengths of the bonds between cations and oxygens and the structural roles of the individual elements in the glass are the predominant factors controlling the composition dependence of the chemical durability of glasses. The structural roles of oxides in glass are classified as network formers, network breakers, and intermediates. The structural roles of the oxides depend on glass composition and the redox state of oxides. Al2O3, ZrO2, Fe2O3, and B2O are assigned as network formers only when there are sufficient alkalis to bind with these oxides CaO can also improve durability by sharing non-bridging oxygen with alkalis, relieving SiO2 from alkalis. The binding order to alkalis is Al2O3 > ZrO2 > Fe2O3 > B2O3 > CaO > SiO2. The percolation phenomenon in glass is also taken into account. The concentration of network formers as to reach a critical value for a glass to become durable; durable glasses are sufficient in network formers and have a complete network structure; poor durability glasses are deficient in network formers and the network is incomplete and discontinuous. The SBS model is capable of correlating the 7-day product consistency test durability of 42 low-level waste glasses with their composition with an R2 of 0.87, which is better than 0.81 obtained with an eight-coefficient empirical first-order mixture model on the same data

  3. An Experimental Investigation On Minimum Compressive Strength Of Early Age Concrete To Prevent Frost Damage For Nuclear Power Plant Structures In Cold Climates

    International Nuclear Information System (INIS)

    Concrete undergoing early frost damage in cold weather will experience significant loss of not only strength, but also of permeability and durability. Accordingly, concrete codes like ACI-306R prescribe a minimum compressive strength and duration of curing to prevent frost damage at an early age and secure the quality of concrete. Such minimum compressive strength and duration of curing are mostly defined based on the strength development of concrete. However, concrete subjected to frost damage at early age may not show a consistent relationship between its strength and durability. Especially, since durability of concrete is of utmost importance in nuclear power plant structures, this relationship should be imperatively clarified. Therefore, this study verifies the feasibility of the minimum compressive strength specified in the codes like ACI-306R by evaluating the strength development and the durability preventing the frost damage of early age concrete for nuclear power plant. The results indicate that the value of 5 MPa specified by the concrete standards like ACI-306R as the minimum compressive strength to prevent the early frost damage is reasonable in terms of the strength development, but seems to be inappropriate in the viewpoint of the resistance to chloride ion penetration and freeze-thaw. Consequently, it is recommended to propose a minimum compressive strength preventing early frost damage in terms of not only the strength development, but also in terms of the durability to secure the quality of concrete for nuclear power plants in cold climates

  4. Quality of durable cookies enriched with rape bee pollen

    Directory of Open Access Journals (Sweden)

    Miriam Solgajová

    2014-03-01

    Full Text Available The objective of this study was to enrich durable cookies with different additions of rape (Brassica napus var. napus bee pollen to increase nutritional properties of cookie samples and to improve technological and sensorial properties as well. Bee pollen is an important raw material due to its nutritional and functional properties. Cookie samples were prepared by substituting wheat flour with rape bee pollen in the amount of 16 % (1 g of bee pollen per cookie and 32 % (2 g of bee pollen per cookie using bee pollen from two localities Lenártovce and Nové Zámky. In baked samples beside sensory properties also chemical parameters and technological parameters of cookies were evaluated. It was found out that with the gradual addition of rape bee pollen the amount of ash content increased and the highest ash content was analysed in variants II and IV (0.71 and 0.77 % using 32 % addition of rape bee pollen. In terms of reducing sugars, addition of bee pollen caused that the content of reducing sugars in the products increased slightly. The highest reducing sugar content was determined in variant II. (24.59 %. On the other hand amount of crude protein the most considerably raised by addition of 2 g of pollen per cookie. The highest content of crude protein was analysed in variants II and IV (8.72 and 9.00 %. From the results of a linear models in which the dependent variables were the ash, crude protein and moisture it was determined the significant effect (p <0.05 only of the pollen addition. In the case of the model with the dependent variable reducing sugars it was found out significant effect (p<0.0001 of pollen addition and locality and their interactions. With the gradual addition of bee pollen values of technological parameters such as diameter and weight of cookies increased and thickness of products decreased. Based on sensory scores using a 9-point Hedonic scale the best sensorial acceptability (7.4 was found in variant I (1 g of bee

  5. Chemical durability of hollandite ceramic for conditioning cesium

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, Frederic [CEA Marcoule, DEN/DTCD/SECM/LCLT, F-30207 Bagnols-sur-Ceze (France)], E-mail: frederic.angeli@cea.fr; McGlinn, Peter [ANSTO, New Illawarra Road, Menai, PMB1, NSW 2234 (Australia); Frugier, Pierre [CEA Marcoule, DEN/DTCD/SECM/LCLT, F-30207 Bagnols-sur-Ceze (France)

    2008-10-15

    The aqueous corrosion behavior of Cs-doped hollandite ceramic (BaCs{sub 0.28}Fe{sub 0.82}Al{sub 1.46}Ti{sub 5.72}O{sub 16}) was studied using several different static experimental protocols, with leachants of varying pH, and at different surface area to volume ratios, for periods ranging from six months to three years. All leach tests were carried out at 90 deg. C. X-ray diffraction (XRD) and scanning electron microscopy (SEM), coupled with energy dispersive X-ray spectroscopy (EDS), were used to characterize the surfaces of the hollandite before and after leaching. The most pronounced elemental releases, and corresponding changes to surface composition and microstructure, was evident at low pH, in particular pH 1. Cs and Ba releases were highest at low pH, with surface alteration exhibited by the formation of secondary rutile (prevalent at pH 1) and Al- and Ba-depleted hollandite (prevalent at pH 2). After rapid initial Cs release, the alteration rate was extremely low over the pH range from 2 to 10, as well as in pure water experiments with a sample-surface-area-to-solution-volume ratio ranging from 0.1 cm{sup -1} to 1200 cm{sup -1}. The rates were about 10{sup -5} g m{sup -2} d{sup -1}, corresponding to alteration thicknesses of a few nanometers per year. Higher rates (5 x 10{sup -3} g m{sup -2} d{sup -1}) were observed only under very acidic conditions (pH 1). Congruency in Cs and Ba releases occurred only at pH 1, with incongruency between the two elements increasing with increasing pH. There were no apparent solubility constraints on Cs releases regardless of the SA/V ratio, whereas geochemical modeling suggested that Ba releases could have been affected by the formation of BaCO{sub 3}, particularly at high SA/V ratios. Extended leaching (with the leachant renewed once after 261 days of leaching) confirmed the high durability of hollandite with altered thicknesses of less than one nanometer per year over the last two years. Whilst Cs depletion of the

  6. Properties and durability of metakaolin blended cements: mortar and concrete

    Directory of Open Access Journals (Sweden)

    Abbas, Rafik

    2010-12-01

    Full Text Available This article explores the effect of metakaolin, a pozzolan, on concrete performance. Compressive and splitting tensile strength were found for specimens cured for up to 360 and 90 days, respectively. Changes were recorded in the compressive strength of specimens exposed to salt (chloride and sulfatechloride solutions, and chloride penetration and binding capacity were measured. The findings were compared to the results for concrete prepared with ordinary Portland (OPC and moderate heat of hydration (Type II cement. MK was found to have a very positive effect on 28-day concrete strength, due to microstructure improvement of the hydrated cement. Replacing cement with metakaolin effectively raised concrete resistance to chloride attack. Concrete containing metakaolin proved to be substantially more durable in sulfate-chloride environment.

    En este trabajo se estudia el efecto del metacaolín sobre las prestaciones del hormigón. Las probetas curadas a 360 y 90 días se sometieron a ensayos de resistencia a compresión y de tracción indirecta respectivamente. Se hizo un seguimiento de la resistencia a la compresión de los materiales ante el ataque de sales (soluciones de cloruro y de sulfato-cloruro y, se midió la penetración de cloruros y la capacidad de los hormigones de inmovilizar estos iones. Los resultados se compararon con los obtenidos con hormigones elaborados con cemento pórtland ordinario (OPC y, con cemento de calor de hidratación moderado (tipo II. El MK resultó influir muy positivamente en la resistencia del hormigón a 28 días debido a la mejora de la microestructura del cemento hidratado. La sustitución de cemento por metacaolín aumentó la resistencia del hormigón al ataque de cloruros. El hormigón con metacaolín demostró ser más duradero en entornos de sulfato-cloruro que los hormigones elaborados con OPC o con cemento de tipo II. Los perfiles de concentración de cloruros a distintas profundidades y la

  7. Durability of solid oxide electrolysis cells for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Hauch, A.; Hoejgaard Jensen, S.; Dalgaard Ebbesen, S.

    2007-05-15

    In the perspective of the increasing interest in renewable energy and hydrogen economy, the reversible solid oxide cells (SOCs) is a promising technology as it has the potential of providing efficient and cost effective hydrogen production by high temperature electrolysis of steam (HTES). Furthermore development of such electrolysis cells can gain from the results obtained within the R and D of SOFCs. For solid oxide electrolysis cells (SOEC) to become interesting from a technological point of view, cells that are reproducible, high performing and long-term stable need to be developed. In this paper we address some of the perspectives of the SOEC technology i.e. issues such as a potential H2 production price as low as 0.71 US dollar/kg H{sub 2} using SOECs for HTES; is there a possible market for the electrolysers? and what R and D steps are needed for the realisation of the SOEC technology? In the experimental part we present electrolysis test results on SOCs that have been optimized for fuel cell operation but applied for HTES. The SOCs are produced on a pre-pilot scale at Risoe National Laboratory. These cells have been shown to have excellent initial electrolysis performance, but the durability of such electrolysis cells are not optimal and examples of results from SOEC tests over several hundreds of hours are given here. The long-term tests have been run at current densities of -0.5 A/cm{sup 2} and -1 A/cm{sup 2}, temperatures of 850 deg. C and 950 deg. C and p(H{sub 2}O)/p(H{sub 2}) of 0.5/0.5 and 0.9/0.1. Long-term degradation rates are shown to be up to 5 times higher for SOECs compared to similar SOFC testing. Furthermore, hydrogen and synthetic fuel production prices are calculated using the experimental results from long-term electrolysis test as input and a short outlook for the future work on SOECs will be given as well. (au)

  8. Improving the durability of a drag-reducing nanocoating by enhancing its mechanical stability.

    Science.gov (United States)

    Cheng, Mengjiao; Zhang, Songsong; Dong, Hongyu; Han, Shihui; Wei, Hao; Shi, Feng

    2015-02-25

    The durability of superhydrophobic surface is a major problem to restrict industrial application of superhydrophobic materials from laboratory research, which can be attributed to a more general issue of mechanical stability for superhydrophobic coatings. Therefore, in order to handle this issue, we have fabricated a mechanically stable drag-reducing coating composed of elastic polydimethylsiloxane (PDMS) and hydrophobic copper particles on model ships, which can resist mechanical abrasion and has displayed a durable drag-reducing effect. In comparison with normal Au superhydrophobic coatings, the as-prepared PDMS/copper coatings showed durable drag reduction performance with a similar drag-reducing rate before (26%) and after (24%) mechanical abrasion. The mechanism for the enhanced mechanical stability and maintained drag reduction of the superhydrophobic surfaces was investigated through characterizations of surface morphology, surface wettability, and water adhesive force evaluation before and after abrasion. This is the first demonstration to realize the application of durable drag reduction by improving the mechanical stability of superhydrophobic coatings. We do believe that superhydrophobic surfaces with good resistance to mechanical abrasion or scratching may draw wide attention and gain significant applications with durable drag-reducing properties. PMID:25644454

  9. First-order model for durability of Hanford waste glasses as a function of composition

    International Nuclear Information System (INIS)

    This paper discusses two standard chemical durability tests, the static leach test (MCC-1) and product consistency test (PCT), which were conducted on simulated borosilicate glasses that encompass the expected range of compositions to be produced in the Hanford Waste Vitrification Plant. A first-order empirical model was fitted to the data from each test method. The results indicate that glass durability is increased by addition of Al2O3, moderately increased by addition of ZrO2 and SiO2, and decreased by addition of Li2O, Na2O, B2O3, and MgO. Additions of CaO and Fe2O3 reduce MCC-1 durability and produce a moderately positive (CaO) or indifferent (Fe2O3) effect on PCT durability. The first-order models show a statistically significant lack-of-fit, which is attributed to the effects of multiple chemical reactions occurring during glass-water interaction. Liquid-liquid immiscibility is suspected to be responsible for extremely low durability of some glasses

  10. Measurement of Exterior Foundation Insulation to Assess Durability in Energy-Saving Performance

    Energy Technology Data Exchange (ETDEWEB)

    Kehrer, Manfred [ORNL; Christian, Jeff [Oak Ridge National Laboratory (ORNL)

    2012-04-01

    The foundation of a house is a sometimes ignored component of the building because of its low visibility. It is increasingly evident, however, that attention to good foundation design and construction significantly benefits the homeowner and the builder by mitigating future problems. Good foundation design and construction practice involves not only insulating to save energy but also providing effective structural design as well as moisture, termite, and radon control techniques as appropriate. Energy efficiency in housing is augmented by use of exterior slab and basement insulation, but high moisture content in the insulation material has led to concerns about its durability. The activity under this task was to extract six different exterior insulation systems that were characterized at installation and have been in the ground for 9 months to 15 years. R-value and moisture content were measured and inspections conducted for evidence of termite intrusion or deterioration. Based on the results, the durability of the various systems has been documented and assessments made of which systems appear to be best practice. Heat flux and temperature measurement data had been archived for some of the exterior insulation tests, thereby providing a unique opportunity to assess energy-saving performance and durability over the long term. The results show that the durability of foundation insulation systems depends on insulation type as well as on foundation type and local boundary conditions, the latter of which may have a marked influence on the durability of energy-saving performance.

  11. Durability of low-pH injection grout. A literature survey

    International Nuclear Information System (INIS)

    This publication provides an overview of the durability of injection grouts. It is intended for use during planning and construction at the ONKALO underground research facility. The review has been done with respect to the application conditions, materials and service life requirements expressed by Posiva Oy. The publication describes all types of cement-based material durability, with an emphasis on the key issues of shrinkage cracking, leaching and sulphate attack. The second part of the report provides information on how durability expectations have changed with the history of injection grout development. The report gives information specific to low-pH injection grouts containing high amounts of silica fume performance and how their durability is expected to differ from traditional normal cement-based mixtures. The final part of the report provides suggestions for future research needs for ensuring the service life of injection grouts. The key finding from this study is that the low-pH grout material is not expected to have worse durability performance compared to the standard injection grout. Combining high amounts of silica fume with the cement to produce low-pH grout should result in a material having lower permeability and thus greater resistance to leaching and chemical attack. Further laboratory testing is needed to quantitatively verify these findings and to provide inputs for future service life modeling. (orig.)

  12. Beta cloth durability assessment for Space Station Freedom (SSF) Multi-Layer Insulation (MLI) blanket covers

    International Nuclear Information System (INIS)

    MLI blankets for the Space Station Freedom (SSF) must comply with general program requirements and recommendations for long life and durability in the low-Earth orbit (LEO) environment. Atomic oxygen and solar ultraviolet/vacuum ultraviolet are the most important factors in the SSF natural environment which affect materials life. Two types of Beta cloth (Teflon coated woven glass fabric), which had been proposed as MLI blanket covers, were tested for long-term durability in the LEO environment. General resistance to atomic oxygen attack and permeation were evaluated in the high velocity atomic oxygen beam system at Los Alamos National Laboratories. Long-term exposure to the LEO environment was simulated in the laboratory using a radio frequency oxygen plasma asher. The plasma asher treated Beta cloth specimens were tested for thermo-optical properties and mechanical durability. Space exposure data from the Long Duration Exposure Facility and the Intelsat Solar Array Coupon were also used in the durability assessment. Beta cloth fabricated to Rockwell specification MBO 135-027 (Chemglas 250) was shown to have acceptable durability for general use as an MLI blanket cover material in the LEO environment while Sheldahl G414500 should be used only in locations which are protected from direct Ram atomic oxygen

  13. A review of the gas diffusion layer in proton exchange membrane fuel cells: Durability and degradation

    International Nuclear Information System (INIS)

    Highlights: • This paper focuses on the evaluation of the durability characteristics of GDL. • GDL degradation can be categorized into mechanical and chemical degradation. • Standardized test protocols need to be established to evaluate GDL durability. - Abstract: For successful commercialization of a proton exchange membrane fuel cell, the durability requirement must be satisfied. The degradation of a proton exchange membrane fuel cell has been extensively studied, and a number of review papers investigating the durability issue have already been published. However, the gas diffusion layer has rarely been examined, even though it might be a key factor for managing mass transport and two-phase flow while mechanically supporting a membrane-electrode assembly and a bipolar plate. This paper reviews the published works on the durability of the gas diffusion layer of the proton exchange membrane fuel cell. The degradation of the gas diffusion layer can be divided into mechanical degradation, including the compression force effect, freeze/thaw cycle effect, dissolution effect, and erosion effect, and chemical degradation, which consists of the carbon corrosion effect. Following these categories, the methods of accelerated stress tests, the degradation mechanisms, and the influential factors are investigated along with various measurements of gas diffusion layer properties and cell performances

  14. [Effect of the dispersion of calcium deposits on allogenic aortic valves durability. Mineralization phases].

    Science.gov (United States)

    Lis, Grzegorz J; Rokita, Eugeniusz; Podolec, Piotr; Gajda, Mariusz; Sadowski, Jerzy; Cichocki, Tadeusz

    2004-01-01

    This investigation was aimed at comparison of calcium content and calcium dispersion in allogenic aortic valve leaflets removed due to dysfunction, to establish the influence of both parameters on graft durability. Calcification was assessed histochemically (von Kossa) as well as physicochemically using atomic absorption spectroscopy (AAS). The morpho-metric data (leaflet area involved in the calcification process) were obtained by computer-assisted image analysis system. The dry weight content of leaflet calcium and phosphorus were assessed by atomic absorptive spectroscopy (AAS) and Ca/P ratio was calculated. Calcium dispersion coefficient (Dc) was established according to the formula: Dc = 1/Ca(c)/Ap, where Ca(c) = calcium dry weight concentration; Ap = percent of leaflet area involved in calcification. We found biphasic correlation between calcium concentration and area involved in calcification. The first one was characterized by rising dispersion of calcium deposits while for the second one saturation with hydroxyapatite of formerly calcified areas was predominant, negatively influencing graft durability. Allograft durability was correlated with calcium dispersion (Dc) (p<0.001), while no significant correlation was found with calcium concentration. Decreased Dc was characteristic for 93.8% of low durability grafts (<11.6 years). Our results suggest that lowered calcium dispersion decreasing allograft lifetime and is a better predictor of allograft durability than the total calcium content. PMID:15724647

  15. Preventive maintenance

    International Nuclear Information System (INIS)

    The information contained in this paper should be used in conjunction with the maintenance instructions provided by the manufacturer of each valve. When there is any question or conflict between the procedure described and the manufacturer's, the author suggests determining the best method for the applications. A good long range preventative maintenance program for valves will eliminate costly repairs or replacement of valves long before their time. A little flush, lube, and what was once called elbow grease will also go a long way in reducing your downtime and maintenance budget. This paper will discuss one of the most misunderstood theories concerning valve maintenance, i.e., that periodic maintenance of valves includes the injection of sealants. Sealants are injected into valves as a secondary seal for most valves. Under normal conditions, valves do not require sealant injection. Solid fillers in sealants tend to plug the system making it virtually impossible to inject either sealant or a lubricant, requiring the injection of flush or cleaners to dislodge the solids. Topics covered in this paper will range from general maintenance requirements to valve flushing, cleaning and lubrication

  16. Predicting the long-term durability of hemp-lime renders in inland and coastal areas using Mediterranean, Tropical and Semi-arid climatic simulations.

    Science.gov (United States)

    Arizzi, Anna; Viles, Heather; Martín-Sanchez, Inés; Cultrone, Giuseppe

    2016-01-15

    Hemp-based composites are eco-friendly building materials as they improve energy efficiency in buildings and entail low waste production and pollutant emissions during their manufacturing process. Nevertheless, the organic nature of hemp enhances the bio-receptivity of the material, with likely negative consequences for its long-term performance in the building. The main purpose of this study was to study the response at macro- and micro-scale of hemp-lime renders subjected to weathering simulations in an environmental cabinet (one year was condensed in twelve days), so as to predict their long-term durability in coastal and inland areas with Mediterranean, Tropical and Semi-arid climates, also in relation with the lime type used. The simulated climatic conditions caused almost unnoticeable mass, volume and colour changes in hemp-lime renders. No efflorescence or physical breakdown was detected in samples subjected to NaCl, because the salt mainly precipitates on the surface of samples and is washed away by the rain. Although there was no visible microbial colonisation, alkaliphilic fungi (mainly Penicillium and Aspergillus) and bacteria (mainly Bacillus and Micrococcus) were isolated in all samples. Microbial growth and diversification were higher under Tropical climate, due to heavier rainfall. The influence of the bacterial activity on the hardening of samples has also been discussed here and related with the formation and stabilisation of vaterite in hemp-lime mixes. This study has demonstrated that hemp-lime renders show good durability towards a wide range of environmental conditions and factors. However, it might be useful to take some specific preventive and maintenance measures to reduce the bio-receptivity of this material, thus ensuring a longer durability on site. PMID:26551276

  17. Mechanism and Durability of Repair Systems in Polymer-Modified Cement Mortars

    Directory of Open Access Journals (Sweden)

    Ru Wang

    2015-01-01

    Full Text Available This paper investigated the mechanism and durability of repair systems made of ordinary cement-based repair mortar and three kinds of polymer-modified repair mortars with old concrete, SBR dispersion, SAE dispersion, and SAE powder. By comparing the bonding properties of mortars before and after erosion, it was found that polymers could effectively improve the durability of the repair system and SAE powder had the best improvement. Micromorphology study of the repair mortar and the interface of repair mortar with old concrete through SEM showed that the polymer film formed from SAE powder whatever in the mortar or at the interface was dense and tough, the film formed from SAE dispersion was loose and weak, while the film formed from SBR dispersion was in between them, which explained the difference in the tensile bond strength and the durability of the repair systems.

  18. Recent results on the effect of gamma radiation on the durability and microstructure of DWPF glass

    International Nuclear Information System (INIS)

    The effect of gamma radiation on the durability and microstructure of a simulated nuclear waste glass from the Savannah River Site has been carefully investigated. Three large pieces of glass were irradiated with a Co-60 source to three doses up to a maximum dose of 3.1 x 1010 rad. Internal samples of the large pieces of irradiated and unirradiated glass were leached in deionized water to investigate durability changes and were examined by transmission electron microscopy (TEM) to investigate microstructure changes. Leach tests were performed in triplicate at 90 degree C with crushed glass samples in deionized water. A statistical analysis of the results indicated to the 95% confidence level that the radiation did not affect the glass durability. Careful examination by TEM indicated no effect of gamma radiation on the microstructure of the glass although severe damage could be induced by the electron beam from the microscope. 19 refs., 2 figs., 3 tabs

  19. Predicting the Durability of Concrete Structures, including Sulfate Corrosion of Concrete

    Directory of Open Access Journals (Sweden)

    V.P. Selyaev

    2014-02-01

    Full Text Available Multiple data on the examination of concrete structures indicate that under the influence of various factors (temperature, humidity, gaseous medium carrying capacity and rigidity during operation are reduced. The problems of assessing the residual life and durability of concrete structures are considered in the article. Experimental studies on the interaction of the concrete samples with aggressive sulfate medium are conducted. By measuring the micro-hardness, isochrones of degradations, enabling experiments to determine the rate of advance of the destruction front deep into the product; intensity changes in the durability properties of the material surface and other features which characterize the degradation process were obtained. The article investigates the mechanisms of corrosion processes in reinforced concrete in condition of sulfate corrosion. The paper proposes the calculation model and the method that predict the durability of concrete structures.

  20. Long-term Durability of Cement-based Materials with Very Low w/b

    Institute of Scientific and Technical Information of China (English)

    XIE Youjun; LIU Yunhua; LONG Guangeheng

    2008-01-01

    To investigate the durability, especially the long-term stability of cement-based materials with very low w/b, the air permeability test, carbonation test, capillary absorption rate test and dilation Dotential test were adopted under long-term heat treatment condition. Microstructure of these materials is also analyzed by scannmg electronic microscopy (SEM) and mercury intrusion porosimeter (MIP) in order to further unveil its mechanism and interrelation between microstructure and its properties. The results indicate that in the area investigated, cement-based material with w/b 0.17, like RPC, possesses low porosity and excellent durability. Moreover, its porosity will further decrease under long-term heat treatment compared with normal heat treatment. Its long-term durability is much superior to that of other cement-based materials with w/b 0.25 or 0.35 as high strength concrete (HSC).

  1. The selection of private brand durable goods: factors affecting the Choice

    Directory of Open Access Journals (Sweden)

    Carmen Pérez Cabañero

    2010-12-01

    Full Text Available Distributors have extended their brand policy to durable good categories such as household appliances and electronic devices, what has been proved to be worthy, although it has received a lot of criticism. Possibly, the higher familiarity of the consumer with private brands, the favourable change of attitude towards them, the availability of technology and, why not, the actual international economic crisis which affects to the domestic economies can be factors which explain this success. The few researches trying to explain the reasons of acceptance of these brands in durable goods have taken us to analyze whether factors determining the purchase of private brands in typical study categories such as food and cosmetics can be applied to durable goods. Preliminary results indicate that it is not possible.

  2. Chemical durability of soda-lime-aluminosilicate glass for radioactive waste vitrification

    International Nuclear Information System (INIS)

    Vitrification has been identified as one of the most viable waste treatment alternatives for nuclear waste disposal. Currently, the most popular glass compositions being selected for vitrification are the borosilicate family of glasses. Another popular type that has been around in glass industry is the soda-lime-silicate variety, which has often been characterized as the least durable and a poor candidate for radioactive waste vitrification. By replacing the boron constituent with a cheaper substitute, such as silica, the cost of vitrification processing can be reduced. At the same time, addition of network intermediates such as Al2O3 to the glass composition increases the environmental durability of the glass. The objective of this study is to examine the ability of the soda-lime-aluminosilicate glass as an alternative vitrification tool for the disposal of radioactive waste and to investigate the sensitivity of product chemical durability to variations in composition

  3. Durability of reinforced concrete beams strengthened with fiber reinforced polymers under varying environmental conditions

    International Nuclear Information System (INIS)

    Fiber reinforced polymers (FRP) materials were adopted by the aerospace and marine industries, not only for their lightweight and high strength characteristics but also due to their tough and durable nature . As the engineering community has become more familiar with the performance advantages of these materials, new applications have been investigated and implemented. Researches and design guidelines concluded that externally bonded FRP to concrete elements could efficiently increase the capacity of RC elements. Long-term exposure to harsh environments deteriorates concrete and the need for repair and rehabilitation is evident. In order to accept these FRP materials, they must be evaluated for durability in harsh environments. An experimental program was conducted at the materials laboratory- faculty of engineering-Ain Shams university to study the durability of RC beams strengthened with FRP sheets and to compare them with un strengthened beams.The effect of gamma rays on FRP materials and concrete specimens bonded to FRP sheets were also investigated.

  4. Mixed hydrocarbon/fluoropolymer membrane/ionomer MEAs for durability studies

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bo [Los Alamos National Laboratory; Kim, Yu Seung [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Wilson, Mahlon S [Los Alamos National Laboratory; Welch, Cynthia [Los Alamos National Laboratory; Fenton, James [FLORIDA SOLAR ENERGY CENTER

    2010-01-01

    The durability of polymer electrolyte membrane (PEM) fuel cells is a major barrier to the commercialization of these systems for stationary and transportation power applications. Commercial viability depends on improving the durability of the fuel cell components to increase the system reliability. The aim of this work is to separate ionomer degradation from membrane degradation via mixed membrane/ionomer MEA experiments. The challenges of mixed MEA fabrication due to the incompatibility of the membrane and the electrode are addressed. OCV accelerated testing experiment (AST) were performed. Development of in situ diagnostics and unique experiments to characterize the performance and properties of the ionomer in the electrode as a function of time is reported. These measurements, along with extensive ex situ and post-mortem characterization, can delineate the degradation mechanisms in order to develop more durable fuel cells and fuel cell components.

  5. Coating Silicon-Based Ceramics With Durable Mullite

    Science.gov (United States)

    Miller, Robert A.; Jacobson, Nathan S.; Lee, Kang N.

    1996-01-01

    Improved plasma-spraying process deposits mullite on silicon carbide substrates. Prevents formation of amorphous mullite by maintaining high temperature of sprayed deposite to allow crystallization to occur. Deposited mullite adheres to substrate and exhibits little or no cracking during thermal cycling. Provides substantially greater resistance to oxidation in dry air and corrosion by molten salt. Process expected useful in depositing mullite on substrates made of other silicon-based ceramics and other ceramic substrates having coefficients of thermal expansion similar to those of mullite.

  6. Influence of ceria on the thermally durability of Pt/Rh automotive catalyst

    International Nuclear Information System (INIS)

    Full text: The use of cerium oxide as an oxygen storage component in automotive three-way catalysts has been well established. More recently the requirement of the three-way catalysts against the increase of the severity in emission standards has focused attention on the development of more active, durable catalysts. The thermally durability of Pt/Rh catalyst can be achieved by the utilization of thermally stable ceria as well as optimization of washcoat composition and structure in order to control the extent of interaction between PGM and ceria. In the present paper, we describe the influence of newly developed washcoat components and PGM interaction with ceria on catalytic performance. First, to clear that the interaction between PGM and ceria contributes to catalytic performance, several kinds of catalysts which have the varied interactions between PGM and ceria were prepared using engineered washcoat techniques and evaluated in the model gas reactor. It was obvious that the difference in performance among them after aging derived from a diversity of interactions between Pt, Rh, and ceria. Second, for the purpose of determining the thermally durability of the developed Pt/Rh catalyst, the catalysts including the current catalyst were aged under three different temperatures and evaluated on engine dynamometer. Result of engine dynamometer evaluation revealed that significant improvement in the thermal durability can be achieved by optimizing the PGM-ceria interaction. In conclusion, we recognize that a thermal durability of a three-way catalyst can be improved by the stabilization of proper PGM-ceria interaction after aging as well as the utilization of thermally durable ceria material

  7. Durability-Based Design Guide for an Automotive Structural Composite: Part 2. Background Data and Models

    Energy Technology Data Exchange (ETDEWEB)

    Corum, J.M. [ORNL; Battiste, R.L. [ORNL; Brinkman, C.R. [ORNL; Ren, W. [ORNL; Ruggles, M.B. [ORNL; Weitsman, Y.J. [ORNL; Yahr, G.T. [ORNL

    1998-02-01

    This background report is a companion to the document entitled ''Durability-Based Design Criteria for an Automotive Structural Composite: Part 1. Design Rules'' (ORNL-6930). The rules and the supporting material characterization and modeling efforts described here are the result of a U.S. Department of Energy Advanced Automotive Materials project entitled ''Durability of Lightweight Composite Structures.'' The overall goal of the project is to develop experimentally based, durability-driven design guidelines for automotive structural composites. The project is closely coordinated with the Automotive Composites Consortium (ACC). The initial reference material addressed by the rules and this background report was chosen and supplied by ACC. The material is a structural reaction injection-molded isocyanurate (urethane), reinforced with continuous-strand, swirl-mat, E-glass fibers. This report consists of 16 position papers, each summarizing the observations and results of a key area of investigation carried out to provide the basis for the durability-based design guide. The durability issues addressed include the effects of cyclic and sustained loadings, temperature, automotive fluids, vibrations, and low-energy impacts (e.g., tool drops and roadway kickups) on deformation, strength, and stiffness. The position papers cover these durability issues. Topics include (1) tensile, compressive, shear, and flexural properties; (2) creep and creep rupture; (3) cyclic fatigue; (4) the effects of temperature, environment, and prior loadings; (5) a multiaxial strength criterion; (6) impact damage and damage tolerance design; (7) stress concentrations; (8) a damage-based predictive model for time-dependent deformations; (9) confirmatory subscale component tests; and (10) damage development and growth observations.

  8. Développement durable et entreprises : du concept à la typologie

    OpenAIRE

    Mathieu, Annelise

    2006-01-01

    Débats publics, conférences, concertations, nul ne peut plus nier que le contexte est aujourd'hui résolument tourné vers le développement durable. Concept " caméléon ", " multiforme " ou " pluridimensionnel " pour certains, " polymorphe " ou " fourre-tout " pour d'autres, le développement durable souffre pourtant d'une cruelle absence de consensus dans le monde de la recherche en sciences de gestion. Face à l'éclectisme dont font preuve les travaux sur le sujet, cette recherche participe aux ...

  9. An Evaluation of the Durability of Polymer Concrete Bonds to Aluminum Bridge Decks

    OpenAIRE

    Zhang, Huiying

    1999-01-01

    The objective of this study is to evaluate the bond durability of an epoxy-based polymer concrete wearing surface bonded to aluminum bridge decks. In the bridge design, an aluminum alloy bridge deck is used with a polymer concrete wearing surface. A modified mixed mode flexure fracture test was developed to assess the bond durability of specimens aged in the following environmental conditionings: 30°C [86°F], 98% RH; 45°C [113°F], 98% RH; 60°C [140°F], 98% RH; freezing and thawing; sal...

  10. Characterization and durability testing of a glass-bonded ceramic waste form

    International Nuclear Information System (INIS)

    Argonne National Laboratory is developing a glass bonded ceramic waste form for encapsulating the fission products and transuranics from the conditioning of metallic reactor fuel. This waste form is currently being scaled to the multi-kilogram size for encapsulation of actual high level waste. This paper will present characterization and durability testing of the ceramic waste form. An emphasis on results from application of glass durability tests such as the Product Consistency Test and characterization methods such as X-ray diffraction and scanning electron microscopy. The information presented is based on a suite of tests utilized for assessing product quality during scale-up and parametric testing

  11. Chemical durability and degradation mechanisms of HT9 based alloy waste forms with variable Zr content

    Energy Technology Data Exchange (ETDEWEB)

    Olson, L. N. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-30

    In Corrosion studies were undertaken on alloy waste forms that can result from advanced electrometallurgical processing techniques to better classify their durability and degradation mechanisms. The waste forms were based on the RAW3-(URe) composition, consisting primarily of HT9 steel and other elemental additions to simulate nuclear fuel reprocessing byproducts. The solution conditions of the corrosion studies were taken from an electrochemical testing protocol, and meant to simulate conditions in a repository. The alloys durability was examined in alkaline and acidic brines.

  12. Proposals for a draft code for design durable concrete structures in the Arabian Gulf

    International Nuclear Information System (INIS)

    The severity of the Arabian Gulf environment demands certain provisions for a design code that would cater to local challenges in concreting. With this view in mind, an apparent climatic divide was identified for the Arabian Peninsula viz. Hot-Dry and Hot-Humid zones which were further classified into an order of exposures, detailing the potential dangers to concrete durability. Moreover, suggestions are included based on both research and experience in the Gulf, to practice essential quantity and quality checks on concrete mix design parameters. It is intended that this contribution would help formulate a draft design code respecting concrete durability in this part of the world. (author)

  13. Recommended Minimum Test Requirements and Test Methods for Assessing Durability of Random-Glass-Fiber Composites

    Energy Technology Data Exchange (ETDEWEB)

    Battiste, R.L.; Corum, J.M.; Ren, W.; Ruggles, M.B.

    1999-06-01

    This report provides recommended minimum test requirements are suggested test methods for establishing the durability properties and characteristics of candidate random-glass-fiber polymeric composites for automotive structural applications. The recommendations and suggestions are based on experience and results developed at Oak Ridge National Laboratory (ORNL) under a US Department of Energy Advanced Automotive Materials project entitled ''Durability of Lightweight Composite Structures,'' which is closely coordinated with the Automotive Composites Consortium. The report is intended as an aid to suppliers offering new structural composites for automotive applications and to testing organizations that are called on to characterize the composites.

  14. Recent Development of Durable and Self-Healing Surfaces with Special Wettability.

    Science.gov (United States)

    Chen, Kunlin; Wu, Yi; Zhou, Shuxue; Wu, Limin

    2016-03-01

    Artificial special wetting surfaces have drawn much interest due to their important applications in many fields. Nevertheless, tremendous challenges still remain for the fabrication of wetting surfaces with durable and self-healing properties. Here, recent progress of durable, self-healing wetting surfaces is highlighted by discussing the fabrications of several typical wetting surfaces including superhydrophobic surfaces, superamphiphobic surfaces, underwater superoleophobic surfaces, and high hydrophilic antifouling surfaces based on expertise and related research experience. To conclude, some perspectives on the future research and development of these special wetting surfaces are presented. PMID:26833559

  15. Examples of feedback, experimental and theoretical approaches for concrete durability assessment

    Directory of Open Access Journals (Sweden)

    Toutlemonde F.

    2011-04-01

    Full Text Available This paper presents some experimental data obtained from UHPFRC (Ultra-High Performance Fibre-Reinforced Concrete being exposed for 10 years in a cooling tower and a high slag content concrete being exposed for 30 years in a marine environment. Experimental data are then used for assessing concrete durability through a theoretical approach, namely performance-based analysis. The results from the application of this approach are consistent with the penetration depth of aggressive agents measured from core samples. Finally a simulation method currently being developed by EDF is presented, which has great relevance to durability assessment.

  16. Asset Pricing and Optimal Portfolio Choice in the Presence of Illiquid Durable Consumption Goods

    OpenAIRE

    Sanford J Grossman; Guy Laroque

    1987-01-01

    We analyze a model of optimal consumption and portfolio selection in which consumption services are generated by holding a durable good. The durable good is illiquid in that a transaction cost must be paid when the good is sold. It is shown that optimal consumption is not a smooth function of wealth; it is optimal for the consumer to wait until a large change in wealth occurs before adjusting his consumption. As a consequence, the consumption based capital asset pricing model fails to hold. N...

  17. Durability and static strength of microcrystalline titanium VT1-0 obtained by equal-channel angular pressing

    Science.gov (United States)

    Betekhtin, V. I.; Dvorak, J.; Kadomtsev, A. G.; Kardashev, B. K.; Narykova, M. V.; Raab, G. K.; Sklenička, V.; Faizova, S. N.

    2015-01-01

    The influence of deformation by equal-channel angular pressing (ECAP) on the durability of titanium (VT1-0 grade) tensile tested under creep conditions has been studied for the first time. It is established that the ECAP-induced transition of titanium to a microcrystalline state leads to a decrease in the durability, while the characteristics of static strength are improved.

  18. Durability of zirconia thermal-barrier ceramic coatings on air-cooled turbine blades in cyclic jet engine operation

    Science.gov (United States)

    Liebert, C. H.; Jacobs, R. E.; Stecura, S.; Morse, C. R.

    1976-01-01

    Thermal barrier ceramic coatings of stabilized zirconia over a bond coat of Ni Cr Al Y were tested for durability on air cooled turbine rotor blades in a research turbojet engine. Zirconia stabilized with either yttria, magnesia, or calcia was investigated. On the basis of durability and processing cost, the yttria stabilized zirconia was considered the best of the three coatings investigated.

  19. A comparison of the long-term durability of nevirapine, efavirenz and lopinavir in routine clinical practice in Europe

    DEFF Research Database (Denmark)

    Reekie, J; Reiss, P; Ledergerber, B;

    2011-01-01

    The durability of combination antiretroviral therapy (cART) regimens can be measured as time to discontinuation because of toxicity or treatment failure, development of clinical disease or serious long-term adverse events. The aim of this analysis was to compare the durability of nevirapine...

  20. Durability of cemented waste in repository and under simulated conditions

    International Nuclear Information System (INIS)

    The research activities performed by Department of Radioactive Waste Management is focused on the products obtained in the LLAW treatment by chemical precipitation and conditioning by cementation. The individual mechanisms participating in the chemical precipitation process are directly dependent on the precipitate properties and structure, which are related with the initial system composition and the precipitation procedure. In the case of conditioning by cementation, the chemical nature and proportion of the sludges or concentrates affect both the hydrolysis of the initial cement components and the reactions of metastable hydration constituents, as well as the mechanical strength and chemical resistance of the hardened cemented matrix. Generally, the study of the precipitation products and their behaviour during cementation or long-term disposal is extremely difficult because of the system complexity (phase composition and structure) and the lack of the non-destructive analytical methods. For a more detailed characterization, Moessbauer Spectroscopy as a complementary analytical method to XRD, was applied for precipitates and cemented matrices. The following systems are considered: iron precipitates obtained during LLAW treatment; iron hydrated oxides structurally modified by the foreign cations; dry and hydrated cement systems. Also considered and discussed were: - influence of precipitation procedure on the decontamination factors; cementation of sludge chemical components; influence of organic complexing agents on the cemented matrix performances and structure; influence of mineral additives on the concrete; durability of cemented waste in repository and under simulated conditions. Moessbauer investigation of iron species formed in precipitation systems simulating LLAW treatment, revealed that the iron compounds obtained by fast neutralization (as in radioactive aqueous waste treatment) have a different structure compared with iron oxides and hydroxides

  1. Load cycle durability of a graphitized carbon black-supported platinum catalyst in polymer electrolyte fuel cell cathodes

    Science.gov (United States)

    Takei, Chikara; Kakinuma, Katsuyoshi; Kawashima, Kazuhito; Tashiro, Keisuke; Watanabe, Masahiro; Uchida, Makoto

    2016-08-01

    We focus on Pt degradation occurring during fuel cell vehicle (FCV) combined drive cycles involving load and open circuit voltage (OCV) just after startup and during idling. Load cycle durability is evaluated as a function of OCV/load holding time, load rate and relative humidity (RH) with a graphitized carbon black-supported platinum catalyst (Pt/GCB) in the cathode. The degradation of Pt/GCB is suppressed for shorter OCV holding times, lower load rates and lower RH. Scanning ion microscopy (SIM) images of membrane cross-sections indicate that the amount of Pt deposited in the membrane decreases during drive cycles involving load with short OCV holding times. Investigations of the Pt distribution in the cathode catalyst layer (CL) by using scanning TEM-EDX show that the dissolution of Pt is suppressed on the membrane side in the CL. The Pt dissolution is accelerated by the high Pt oxidation due to the long OCV holding time. A load cycle with both long OCV holding time and low load inhibits the Pt2+ migration into the membrane but accelerates the Pt particle growth due to electrochemical Ostwald ripening; meanwhile, a load cycle with long OCV holding time at lower RH prevents both the Pt dissolution and particle growth.

  2. Modeling the Rate-Dependent Durability of Reduced-Ag SAC Interconnects for Area Array Packages Under Torsion Loads

    Science.gov (United States)

    Srinivas, Vikram; Menon, Sandeep; Osterman, Michael; Pecht, Michael G.

    2013-08-01

    Solder durability models frequently focus on the applied strain range; however, the rate of applied loading, or strain rate, is also important. In this study, an approach to incorporate strain rate dependency into durability estimation for solder interconnects is examined. Failure data were collected for SAC105 solder ball grid arrays assembled with SAC305 solder that were subjected to displacement-controlled torsion loads. Strain-rate-dependent (Johnson-Cook model) and strain-rate-independent elastic-plastic properties were used to model the solders in finite-element simulation. Test data were then used to extract damage model constants for the reduced-Ag SAC solder. A generalized Coffin-Manson damage model was used to estimate the durability. The mechanical fatigue durability curve for reduced-silver SAC solder was generated and compared with durability curves for SAC305 and Sn-Pb from the literature.

  3. Influence of surface topography on the surface durability of steam oxidised sintered iron

    Directory of Open Access Journals (Sweden)

    José Daniel Biasoli de Mello

    2005-06-01

    Full Text Available Durability of surfaces has been reported as the main factor affecting tribological behavior of steam oxidised sintered iron. The presence of surface pores and their negative influence on load bearing capacity, suggest that surface topography might play an important role on the durability of the oxide layer. In this paper, the influence of compaction pressure and powder grade on surface topography, and as a consequence, its effect on the tribological behavior of steam oxidised sintered iron has been analysed. Specimens prepared from atomised iron powders with different sizes were compacted using 4 different pressures, sintered, and then subjected to steam treatment. Tribological characterisation was carried out in a reciprocating sliding wear test. Although the processing parameters affected the surface topography to a considerable extent, the main influence may be attributed to powder grade. A strong influence of surface topography on the durability distance, evaluated in terms of the evolution of contact resistance with total sliding distance, has been highlighted. Surfaces which were smoother and had high load-carrying capacity were always associated with a higher durability distance.

  4. The design of durable Na+-selective CHEMFETs based on polysiloxane membranes

    NARCIS (Netherlands)

    Brunink, Jos A.J.; Lugtenberg, Ronny J.W.; Brzozka, Zbigniew; Engbersen, Johan F.J.; Reinhoudt, David N.

    1994-01-01

    The design of durable sodium-selective CHEMFETs based on the covalent attachment of a sodium-selective ionophore and tetraphenylborate anions to a polysiloxane membrane matrix is described. Simulations of the membrane potential of such CHEMFETs using an extended version of the model developed previo

  5. 75 FR 26196 - Publication of OIG Updated Special Fraud Alert on Telemarketing by Durable Medical Equipment...

    Science.gov (United States)

    2010-05-11

    ... published on January 10, 2010 (75 FR 2105), addressing our recently issued Updated Special Fraud Alert. Specifically, the Updated Special Fraud Alert addressed the statutory provision prohibiting durable medical... HUMAN SERVICES Office of Inspector General Publication of OIG Updated Special Fraud Alert...

  6. 75 FR 2105 - Publication of OIG Updated Special Fraud Alert on Telemarketing by Durable Medical Equipment...

    Science.gov (United States)

    2010-01-14

    ...; ] DEPARTMENT OF HEALTH AND HUMAN SERVICES Office of Inspector General Publication of OIG Updated Special Fraud... Special Fraud Alert addressing telemarketing by durable medical equipment (DME) suppliers. For the most part, OIG Special Fraud Alerts address national trends in health care fraud, including...

  7. Durable cisgenic resistance to Phytophthora infestans in potato and perspectives for applications in Africa

    NARCIS (Netherlands)

    Gheysen, G.; Heremans, B.; Droogenbroeck, van B.; Custers, R.; Vossen, J.H.; Visser, R.G.F.; Jacobsen, E.; Hutten, R.C.B.; Haverkort, A.J.

    2015-01-01

    Late blight caused by Phytophthora infestans is a major constraint in potato production. A promising strategy to combat late blight in potato is to combine different resistance genes to achieve durable resistance. Resistance genes from wild relatives can be introduced by breeding or by transformatio

  8. Laboratory evaluation of durability of open-graded friction course Mixtures

    Directory of Open Access Journals (Sweden)

    N. A. Qureshi

    2015-06-01

    Full Text Available Open-graded friction courses (OGFC are special purpose thin surface mixtures of hot mix asphalt (HMA pavement that is increasingly being used around the world. Owing to its safety aspects, OGFC is being regularly used as final riding surface on interstate and high speed expressways by different highway agencies in United States, including Alabama Department of Transportation. OGFC pavements in Alabama are facing premature failure due to different reasons. Loss of durability and functionality causes failure of OGFC pavements. Thus, research is needed to improve the durability of OGFC and enhance its beneficial properties. This research proposes methods to improve the durability of OGFC mixtures through laboratory performance testing. Aggregate gradation and layer thickness significantly affected the durability of the OGFC surfaces in general, especially the layer thickness. The Hamburg test indicated a 50-60% higher resistance to moisture damage of OGFC pavement with increase in thickness from 19 mm to 38 mm. The Cantabro stone loss of OGFC pavements is reduced 10- 50% with increase in thickness from 19 mm to 38 mm. The permeability tests results indicated 12-100% increase in permeability with increase in thickness of OGFC pavement from 19 mm to 38 mm. Indirect tensile strength tests indicated 50-300% increase in strength with increase in thickness of OGFC pavement from 19 mm to 38 mm.

  9. Durability of polymer matrix composites for automotive structural applications: A state-of-the-art review

    Energy Technology Data Exchange (ETDEWEB)

    Corum, J.M.; Simpson, W.A. Jr.; Sun, C.T.; Talreja, R.; Weitsman, Y.J.

    1995-07-01

    A key unanswered question that must be addressed before polymeric composites will be widely used in automotive structural components is their known durability. Major durability issues are the effects that cyclic loadings, creep, automotive fluid environments, and low-energy impacts have on dimensional stability, strength, and stiffness throughout the required life of a composite component. This report reviews the current state of understanding in each of these areas. It also discusses the limited information that exists on one of the prime candidate materials for automotive structural applications--an isocyanurate reinforced with a continuous strand, swirl mat. Because of the key role that nondestructive evaluations must play in understanding damage development and progression, a chapter is included on ultrasonic techniques. A final chapter then gives conclusions and recommendations for research needed to resolve the various durability issues. These recommendations will help provide a sound basis for program planning for the Durability of Lightweight Composite Structures Project sponsored by the US Department of Energy in cooperation with the Automotive Composites Consortium of Chrysler, Ford, and General Motors.

  10. FORECASTING OF DURABILITY OF ASPHALT PAVEMENT ON THE BASIS OF LEVELS OF THEIR VIBRATION LOADING

    Directory of Open Access Journals (Sweden)

    V. A. Osinovskaya

    2015-12-01

    Full Text Available The problem of low durability of flexible pavement is one of the most important problems of road economy. For example, the actual service life of asphalt pavement in Russia about 3 … 5 years. The bad condition of highways is an obstacle for the development of the national economy and leads to a significant annual economic losses.At present, this problem has no exact solution. Even at the seeming good road conditions of Europe and America the problem of low durability is no less important in these countries. And this problem becomes more and more actual every year.Our scientific researches allowed to make a hypothesis that the projected of pavements are not have the necessary durability yet not of a stage of designing because in strength calculations did not take into account the vibration of road constructions.Very actual the vibration loading becomes today as is now significantly changed the nature of loading of pavements. As a result the deflections of a pavements are reduced, but the increased vibration of pavements accelerated processes of destruction and significantly reduced durability.The theory of vibration destruction developed by the author allows to adjust the vibration, to form the vibration resistance pavements, and also to forecast a residual life of pavements that will more effectively develop repair actions.

  11. Durability of Solid Oxide Electrolysis Cell and Interconnects for Steam Electrolysis

    DEFF Research Database (Denmark)

    Sun, Xiufu; Chen, Ming; Liu, Yi-Lin; Hendriksen, Peter Vang; Mogensen, Mogens Bjerg

    2013-01-01

    oxygen electrodes degraded during the durability test. The degree of percolation loss in the active Ni-YSZ hydrogen electrode is found to decrease along the steam flow direction whereas the formation of cracks or cavities/pores within the electrolyte shows the opposite trend. The influence of sealing and...

  12. Durability and safety of concrete structures in the nuclear context. The case of the containment vessel

    International Nuclear Information System (INIS)

    The durability of structures, because of its economic and environmental implications, is one of the actual hot topics in civil engineering. In the field of nuclear energy, we are facing very challenging problems like: how could we prolong the service life of actual nuclear containments and how can we assure the durability of a radioactive storage on the very long term (several centuries)? These already difficult questions in a classical civil engineering view are even more complicated in the field of nuclear energy where the structures are massive and the safety of the installations has to be considered. For the containment of nuclear power plants, these stakes will be lit with some examples of research concerning the mechanical behaviour of concrete and concrete structures (at early age, in service on long scales of time and in the event of an accident), the durability of the concrete structures (leaching, swelling due to delayed ettringite formation - DEF -) and the couplings between mechanics and durability. Finally, the importance of probabilistic aspects and the inherent difficulties will be shown. (authors)

  13. Durability of CFRP strengthened concrete structures under accelerated or environmental ageing conditions

    OpenAIRE

    Benzarti, Karim; QUIERTANT, Marc; Chataigner, Sylvain; Aubagnac, Christophe; Nishizaki, Itaru; Kato, Y.

    2008-01-01

    The durability of concrete slabs strengthened by bonded composite materials has been investigated in the framework of an international cooperation between two French and Japanese research institutes. Time evolution of the concrete/composite adhesive bond strength was studied under both controlled and environmental ageing conditions, by using different mechanical characterization methods. The first results of this ongoing experimental campaign are presented.

  14. Feed Pellet and Corn Durability and Breakage During Repeated Elevator Handling

    Science.gov (United States)

    Pelleting of animal feeds is important for improved feeding efficiency and for convenience of handling. Pellet quality impacts the feeding benefits for the animals and pellet integrity during handling. To determine the effect of repeated handling on feed pellet breakage and durability, a 22.6-t (100...

  15. Skid resistance and durability of coated and uncoated concrete floors in dairy cattle buildings

    OpenAIRE

    Georg, Heiko

    2011-01-01

    Passageways in cattle buildings should provide durable and non-slippery surface to allow cattle an unrestrained locomotion and expression of behaviour. In order to evaluate walking areas fo cattle buildings and their grip or skid resistance, measures with Skid Resistance Tester to obtain SRT-values were performed on sevreal dairy farms in Germany.

  16. Hydrophobic lime based mortars with linseed oil: Characterization and durability assessment

    Czech Academy of Sciences Publication Activity Database

    Nunes, Cristiana Lara; Slížková, Zuzana

    61-62, July-August (2014), s. 28-39. ISSN 0008-8846 R&D Projects: GA MK(CZ) DF11P01OVV008 Keywords : durability * transport properties * metakaolin * mortar Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.864, year: 2014 http://www.sciencedirect.com/science/article/pii/S0008884614000738

  17. Durability of Solid Oxide Electrolysis Cell and Interconnects for Steam Electrolysis

    DEFF Research Database (Denmark)

    Sun, Xiufu; Chen, Ming; Liu, Yi-Lin; Hendriksen, Peter Vang; Mogensen, Mogens Bjerg

    2013-01-01

    Durability of a solid oxide electrolysis cell tested at -1.5A / cm2 for high temperature steam electrolysis was investigated in the present work under stack relevant conditions. Detailed electrochemical and microstructural analyses were carried out. The results show that both the hydrogen and the...... interconnects on cell degradation under harsh electrolysis conditions is further discussed....

  18. 42 CFR 414.229 - Other durable medical equipment-capped rental items.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Other durable medical equipment-capped rental items. 414.229 Section 414.229 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM PAYMENT FOR PART B MEDICAL AND OTHER HEALTH...

  19. Characterization and modelling of self healing of bituminous materials towards durable asphalt pavement

    NARCIS (Netherlands)

    Qiu, J.; Van de Ven, M.F.C.; Schlangen, H.E.J.G.; Wu, S.; Molenaar, A.A.A.

    2012-01-01

    The traffic volume and the number of heavy vehicles are growing enormously nowadays. There is a need for designing a durable asphalt pavement with innovative technologies. Pavement structures and materials with self healing and self repairing capability are believed to be very useful in such a syste

  20. Design and fabrication of durable owner-built wind turbine blades

    Science.gov (United States)

    Queeney, R. A.

    To find the configuration of materials that will produce lightweight, durable wind tubine blades, a composite material blade consisting of an aluminum tubing spar, a foam insulating filler and a glass reinforced plastic skin was analyzed. Various tensile and creep tests were conducted on model blades, and a computer analysis determined the best configuration for the blade.

  1. 42 CFR 410.38 - Durable medical equipment: Scope and conditions.

    Science.gov (United States)

    2010-10-01

    ... supporting documentation, including pertinent parts of the beneficiary's medical record (for example, history... 42 Public Health 2 2010-10-01 2010-10-01 false Durable medical equipment: Scope and conditions... HUMAN SERVICES MEDICARE PROGRAM SUPPLEMENTARY MEDICAL INSURANCE (SMI) BENEFITS Medical and Other...

  2. Long-term elastic durability of polymer matrix composite materials after repeated steam sterilization.

    Science.gov (United States)

    Chong, Alexander C M; Fischer, Gustav; Dart, Bradley R; Wooley, Paul H

    2015-11-01

    We compared the durability of 3 different selected composite materials that underwent repeated steam sterilization with the durability of traditional metal materials. Composite materials Tepex, CFR-PPS (carbon-fiber-reinforced polyphenylene sulfide), and HTN-53 (Zytel HTN53G50HSLR NC010) were evaluated for durability and water retention after repeated steam sterilization. These composites were compared with stainless steel and aluminum. The structural properties of these materials were measured (short-beam load-to-failure and cyclic compression loading tests) before, during, and after repeated steam sterilization. The relative radiographic density of these materials was also compared. There was no significant difference in the moisture retention of these composite materials before and after repeated sterilization. The composite materials were significantly more radiolucent than the metals. For all the composite materials, load to failure deteriorated after repeated sterilization. The cyclic compression loading tests showed HTN-53 had the poorest performance, with complete failure after 400 cycles of repeated sterilization. CFR-PPS performed slightly better, with 33% failure at final testing. Tepex had no failures at final testing. Although HTN-53 has shown promise in other orthopedic applications, its performance after repeated sterilization was relatively poor. Tepex showed the most potential for durability after repeated sterilization. Further study is needed to identify specific applications for these materials in the orthopedic industry. PMID:26566557

  3. FUNDAMENTAL STUDIES OF THE DURABILITY OF MATERIALS FOR INTERCONNECTS IN SOLID OXIDE FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, J.; Laney, S.; Jackson, W.; Pettit, F.; Meier, J.; Dhanaraj, N.; Beuth, J.

    2005-01-28

    This task involves theoretical analysis of possible alternative metallic interconnect schemes including: Ni and dispersion-strengthened Ni, low CTE alloys based on Fe-Ni (Invar), coatings to suppress evaporation, and incorporation of high conductivity paths. The most promising systems are being evaluated experimentally with regard to durability and oxide conductivity.

  4. First-order model for durability of Hanford waste glasses as a function of composition

    International Nuclear Information System (INIS)

    Two standard chemical durability tests, the static leach test MCC-1 and product consistency test PCT, were conducted on simulated borosilicate glasses that encompass the expected range of compositions to be produced in the Hanford Waste Vitrification Plant (HWVP). A first-order empirical model was fitted to the data from each test method. The results indicate that glass durability is increased by addition of Al2O3, moderately increased by addition of ZrO2 and SiO2, and decreased by addition of Li2O, Na2O, B2O3, and MgO. Addition of Fe2O3 and CaO produce an indifferent or reducing effect on durability according to the test method. This behavior and a statistically significant lack of fit are attributed to the effects of multiple chemical reactions occurring during glass-water interaction. Liquid-liquid immiscibility is suspected to be responsible for extremely low durability of some glasses

  5. Effect of Curing Conditions on the Durability of Ultra-high Performance Concrete under Flexural Load

    Institute of Scientific and Technical Information of China (English)

    GU Chunping; SUN Wei; GUO Liping; WANG Qiannan

    2016-01-01

    We experimentally investigated the effect of curing conditions on the durability of UHPC under flexural load. Moreover, the mechanisms of the effect of curing conditions were revealed from the microstructural point of view with environmental scanning electron microscopy (ESEM) and X-ray computerized tomography (X-ray CT). The experimental results show that the flexural load has negative inlfuence on the durability of UHPC, but UHPC still exhibits excellent durability under lfexural load. Besides, the curing conditions do show inlfuences on the durability of UHPC. Compared with standard and steam curing, oven curing led to a lower chloride resistance and freeze-thaw performance of UHPC. The microstructure of UHPC paste was detected with ESEM. It is revealed that, compared with standard and steam cured UHPC, the lower reaction degree and internal microcracks are the causes for the lower chloride resistance of oven cured UHPC. The defects distribution in UHPC before and after freeze-thaw action was investigated with X-ray CT. The number of defects in oven cured UHPC increases the fastest during the freeze-thaw action due to its more defective microstructure.

  6. The stratified significance of a historic facade as a basis for a more durable conservation approach

    NARCIS (Netherlands)

    Van Roy, N.; Van Balen, K.; Verstrynge, E.; Naldini, S.

    2015-01-01

    In heritage conservation, a gap is often observed between the theory of conservation as a durable process that aims at the preservation of a historic building and the practice of restoration as a single intervention that aims at a fast and convincing result. This paper describes the proposed approac

  7. 77 FR 9522 - Requirements for Consumer Registration of Durable Infant or Toddler Products

    Science.gov (United States)

    2012-02-17

    ..., and the date of manufacture on each such product. 74 FR 68668. The rule specified formatting and text.... 75 FR 7550. Since December 29, 2010, registration forms have been required for all durable infant or... amend the rule in order to clarify or correct certain aspects of the rule. 76 FR 48053. Through...

  8. 75 FR 7550 - Requirements for Consumer Registration of Durable Infant or Toddler Products; Correction

    Science.gov (United States)

    2010-02-22

    ... Register of December 29, 2009 (74 FR 68668). The document issued a final rule under section 104(d) of the... . SUPPLEMENTARY INFORMATION: In FR Doc. E9-30485 appearing on page 68668 in the Federal Register of Tuesday... COMMISSION 16 CFR Part 1130 Requirements for Consumer Registration of Durable Infant or Toddler...

  9. Experimental Investigation on the Durability of Glass Fiber-Reinforced Polymer Composites Containing Nanocomposite

    Directory of Open Access Journals (Sweden)

    Weiwen Li

    2013-01-01

    Full Text Available Nanoclay layers incorporated into polymer/clay nanocomposites can inhibit the harmful penetration of water and chemicals into the material, and thus the durability of glass fiber-reinforced polymer (GFRP composites should be enhanced by using polymer/clay nanocomposite as the matrix material. In this study, 1.5 wt% vinyl ester (VE/organoclay and 2 wt% epoxy (EP/organoclay nanocomposites were prepared by an in situ polymerization method. The dispersion states of clay in the nanocomposites were studied by performing XRD analysis. GFRP composites were then fabricated with the prepared 1.5 wt% VE/clay and 2.0 wt% EP/clay nanocomposites to investigate the effects of a nanocomposite matrix on the durability of GFRP composites. The durability of the two kinds of GFRP composites was characterized by monitoring tensile properties following degradation of GFRP specimens aged in water and alkaline solution at 60°C, and SEM was employed to study fracture behaviors of aged GFRP composites under tension. The results show that tensile properties of the two types of GFRP composites with and without clay degrade significantly with aging time. However, the GFRP composites with nanoclay show a lower degradation rate compared with those without nanoclay, supporting the aforementioned hypothesis. And the modification of EP/GFRP enhanced the durability more effectively.

  10. Moisture sorption, biological durability, and mechanical performance of WPC containing modified wood and polylactates

    Directory of Open Access Journals (Sweden)

    B. Kristoffer Segerholm

    2012-11-01

    Full Text Available Biological durability is an important feature for wood-plastic composites (WPC intended for outdoor applications. One route to achieving WPC products with increased biological durability is to use wood preservative agents in the formulation of the WPC. Another option could be to use a chemically modified wood component that already exhibits increased resistance to biological degradation. There is also a need to use biobased thermoplastics made from renewable resources, which would decrease the dependency on petrochemically-produced thermoplastics in the future. The objective of this study was to examine moisture sorption properties, biological durability, and mechanical performance of injection-molded WPC samples based on acetylated or thermally modified wood components and a polylactate matrix. The biological durability was evaluated in a terrestrial microcosm (TMC test according to ENV 807, followed by mechanical evaluation in a center point bending test. The moisture sorption properties were investigated via both water soaking and exposure in a high-humidity climate. Low or negligible mass losses were observed in the TMC test for all WPC samples. However, the mechanical evaluation after exposure in the TMC test showed 35-40% losses in both strength and stiffness for the WPC containing an unmodified wood component.

  11. Durability of polymeric materials in space : Application of scanning thermal microscopy

    NARCIS (Netherlands)

    Fischer, H.R.; Semprimoschnig, C.O.A.

    2009-01-01

    In this work, a new method, the scanning thermal microscopy method, is applied to study the durability of polymeric materials for space applications. The method was applied to study ground-tested as well as space-retrieved materials. Space-grade silicones, high-temperature polyimides, and the well-k

  12. Calculations of durability of thin-walled shells with account of hydrogenation and aggressive environmental effect

    International Nuclear Information System (INIS)

    A nomogram ascertaining the dependence between the time of fracture and thickness of shell walls for different values of embrittlement indices is presented. Using the nomogram offered it proved possible to define safe radii of the shells under conditions of hydrogenation and corrosive medium influence, as well as to calculate the durability of the shell.6 refs., 1 fig., 1 tab

  13. Bond strength durability of a resin composite on a reinforced ceramic using various repair systems

    NARCIS (Netherlands)

    Ozcan, Mutlu; Valandro, Luiz Felipe; Amaral, Regina; Leite, Fabiola; Bottino, Marco Antonio

    2009-01-01

    Objectives. This study compared the durability of repair bond strength of a resin composite to a reinforced ceramic after three repair systems. Methods. Alumina-reinforced feldspathic ceramic blocks (Vitadur-alpha(R)) (N=30) were randomly divided into three groups according to the repair method: PR-

  14. Lung Cancer Prevention

    Science.gov (United States)

    ... Treatment Lung Cancer Prevention Lung Cancer Screening Research Lung Cancer Prevention (PDQ®)–Patient Version What is prevention? Go ... to keep cancer from starting. General Information About Lung Cancer Key Points Lung cancer is a disease in ...

  15. Child Maltreatment Prevention

    Science.gov (United States)

    ... Resources Featured Topic: Opportunities for Action Featured Topic: Bullying Research Featured Topic: Prevent Gang Membership Featured Topic: School Violence Data & Statistics Risk & Protective Factors Prevention Prevention Tools & Resources Featured Topic: Electronic Aggression Funded ...

  16. Prevent Back Pain

    Science.gov (United States)

    ... Prevent Back Pain Print This Topic En español Prevent Back Pain Browse Sections The Basics Overview Am ... at Risk? 3 of 5 sections Take Action: Prevent Injuries Focus on good posture. Good posture can ...

  17. Performance and durability of high emittance heat receiver surfaces for solar dynamic power systems

    Science.gov (United States)

    Degroh, Kim K.; Roig, David M.; Burke, Christopher A.; Shah, Dilipkumar R.

    1994-01-01

    Haynes 188, a cobalt-based superalloy, will be used to make thermal energy storage (TES) containment canisters for a 2 kW solar dynamic ground test demonstrator (SD GTD). Haynes 188 containment canisters with a high thermal emittance (epsilon) are desired for radiating heat away from local hot spots, improving the heating distribution, which will in turn improve canister service life. In addition to needing a high emittance, the surface needs to be durable in an elevated temperature, high vacuum environment for an extended time period. Thirty-five Haynes 188 samples were exposed to 14 different types of surface modification techniques for emittance and vacuum heat treatment (VHT) durability enhancement evaluation. Optical properties were obtained for the modified surfaces. Emittance enhanced samples were exposed to VHT for up to 2692 hours at 827 C and less than or equal to 10(exp -6) torr with integral thermal cycling. Optical properties were taken intermittently during exposure, and after final VHT exposure. The various surface modification treatments increased the emittance of pristine Haynes 188 from 0.11 up to 0.86. Seven different surface modification techniques were found to provide surfaces which met the SD GTD receiver VHT durability requirement. Of the 7 surface treatments, 2 were found to display excellent VHT durability: an alumina based (AB) coating and a zirconia based coating. The alumina based coating was chosen for the epsilon enhancement surface modification technique for the SD GTD receiver. Details of the performance and vacuum heat treatment durability of this coating and other Haynes 188 emittance surface modification techniques are discussed. Technology from this program will lead to successful demonstration of solar dynamic power for space applications, and has potential for application in other systems requiring high emittance surfaces.

  18. Mixture models versus free energy of hydration models for waste glass durability

    International Nuclear Information System (INIS)

    Two approaches for modeling high-level waste glass durability as a function of glass composition are compared. The mixture approach utilizes first-order mixture (FOM) or second-order mixture (SOM) polynomials in composition, whereas the free energy of hydration (FEH) approach assumes durability is linearly related to the FEH of glass. Both approaches fit their models to data using least squares regression. The mixture and FEH approaches are used to model glass durability as a function of glass composition for several simulated waste glass data sets. The resulting FEH and FOM model coefficients and goodness-of-fit statistics are compared, both within and across data sets. The goodness-of-fit statistics show that the FOM model fits/predicts durability in each data set better (sometimes much better) than the FEH model. Considerable differences also exist between some FEH and FOM model component coefficients for each of the data sets. These differences are due to the mixture approach having a greater flexibility to account for the effect of a glass component depending on the level and range of the component and on the levels of other glass components. The mixture approach can also account for higher-order (e.g., curvilinear or interactive) effects of components, whereas the FEH approach cannot. SOM models were developed for three of the data sets, and are shown to improve on the corresponding FOM models. Thus, the mixture approach has much more flexibility than the FEH approach for approximating the relationship between glass composition and durability for various glass composition regions

  19. Mechanical and Durability Properties of Recycled Concrete Aggregate for Normal Strength Structural Concrete

    Directory of Open Access Journals (Sweden)

    Suvash Chandra Paul

    2013-07-01

    Full Text Available The purpose of this study was to determine the suitability of using Recycled Concrete Aggregate (RCA in structural concrete based on a better understanding of its strength, stiffness and durability. RCA was collected from three different sources: a local landfill site, a local aggregate supplier and from the demolition of two old cooling towers in Cape Town, South Africa (RSA. All RCA was prepared by crushing the demolished concrete in a laboratory crusher at University of Stellenbosch. Their physical properties were determined for comparison of different sources of RCA. RCA replacement percentages of 0%, 30% and 100% to partially replace natural aggregate (NA in concrete were tested at different ages. Cube strength classes 30-40 MPa concrete were made to investigate the mechanical properties of RCA. Creep, shrinkage and durability properties were also tested for concrete with 0% and 30% RCA replacement of NA. It was found that RCA replacement by 30% (RCA30% of NA does not lead to any significant difference in strength and stiffness compared to concrete containing 100% NA in concrete. RCA100% replacement does show reduced strength and stiffness, but this is not significant and can be compensated for in standard ways. Durability index tests indicated similar durability performance of concrete with reasonable quality RCA30% compared with NA100%. Increased creep was however observed for RCA30% which must be considered in structural design. Little information is available about both the mechanical and durability properties of local RCA in RSA, where this research has been performed. The authors believe this report will assist to increase the confidence of engineers to consider using RCA in structural concrete in RSA as well as abroad.

  20. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Preventing Pressure Sores Preventing Pressure Sores Transition from Hospital to Home Transition from Hospital to Home Spasticity, Physical Therapy-Lokomat Spasticity, Physical ...