WorldWideScience

Sample records for amenagement durables volume

  1. Amenagements sportifs et developpement durable : Des enjeux ...

    African Journals Online (AJOL)

    ... contredite » éprouvée par (Jeu, 1977), comme l'apanage d'une double hybridation culturelle des pays en développement. Derrière l'apparence de la dislocation des héritages, doit émerger une définition nouvelle sur les rapports que les sports devraient entretenir avec l'environnement pour un développement durable.

  2. Durability properties of high volume fly ash self compacting concretes

    Energy Technology Data Exchange (ETDEWEB)

    P. Dinakar; K.G. Babu; Manu Santhanam [Indian Institute of Technology, Chennai (India). Building Technology Division

    2008-11-15

    This paper presents an experimental study on the durability properties of self compacting concretes (SCCs) with high volume replacements of fly ash. Eight fly ash self compacting concretes of various strength grades were designed at desired fly ash percentages of 0, 10, 30, 50, 70 and 85%, in comparison with five different mixtures of normal vibrated concretes (NCs) at equivalent strength grades. The durability properties were studied through the measurement of permeable voids, water absorption, acid attack and chloride permeation. The results indicated that the SCCs showed higher permeable voids and water absorption than the vibrated normal concretes of the same strength grades. However, in acid attack and chloride diffusion studies the high volume fly ash SCCs had significantly lower weight losses and chloride ion diffusion.

  3. Advanced Durability Analysis. Volume 2. Analytical Predictions, Test Results and Analytical Correlations

    Science.gov (United States)

    1989-02-27

    Deteministic Crack Growth ApprMach ( CApm -DCG-) Ndaft)/dt m 101Ca )I SUVICE TINE Wh Two-stit btei’uinistic-stochastic Crack Groth Approach (WHO-CG) Figure...physical description of the state of damage for a durability- critical component and a logical basis for estimating structural maintenance/repair require...The stress level for each stress region is important for crack growth predictions. Therefore, the stress analysis for durability- critical components

  4. Relative cerebral blood volume as a marker of durable tissue-at-risk viability in hyperacute ischemic stroke.

    Science.gov (United States)

    Cortijo, Elisa; Calleja, Ana Isabel; García-Bermejo, Pablo; Mulero, Patricia; Pérez-Fernández, Santiago; Reyes, Javier; Muñoz, Ma Fe; Martínez-Galdámez, Mario; Arenillas, Juan Francisco

    2014-01-01

    Selection of best responders to reperfusion therapies could be aided by predicting the duration of tissue-at-risk viability, which may be dependant on collateral circulation status. We aimed to identify the best predictor of good collateral circulation among perfusion computed tomography (PCT) parameters in middle cerebral artery (MCA) ischemic stroke and to analyze how early MCA response to intravenous thrombolysis and PCT-derived markers of good collaterals interact to determine stroke outcome. We prospectively studied patients with acute MCA ischemic stroke treated with intravenous thrombolysis who underwent PCT before treatment showing a target mismatch profile. Collateral status was assessed using a PCT source image-based score. PCT maps were quantitatively analyzed. Cerebral blood volume (CBV), cerebral blood flow, and Tmax were calculated within the hypoperfused volume and in the equivalent region of unaffected hemisphere. Occluded MCAs were monitored by transcranial Duplex to assess early recanalization. Main outcome variables were brain hypodensity volume and modified Rankin scale score at day 90. One hundred patients with MCA ischemic stroke imaged by PCT received intravenous thrombolysis, and 68 met all inclusion criteria. A relative CBV (rCBV) >0.93 emerged as the only predictor of good collaterals (odds ratio, 12.6; 95% confidence interval, 2.9-55.9; P=0.001). Early MCA recanalization was associated with better long-term outcome and lower infarct volume in patients with rCBV<0.93, but not in patients with high rCBV. None of the patients with rCBV<0.93 achieved good outcome in absence of early recanalization. High rCBV was the strongest marker of good collaterals and may characterize durable tissue-at-risk viability in hyperacute MCA ischemic stroke.

  5. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent. Volume 1, Bench-scale testing and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jha, M.C.; Berggren, M.H.

    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.

  6. 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)

  7. Concrete durability

    OpenAIRE

    Gaspar Tébar, Demetrio

    1991-01-01

    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 rese...

  8. 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.)

  9. 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.)

  10. 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

  11. Concrete aggregate durability study.

    Science.gov (United States)

    2009-06-01

    There are many factors that affect the durability of Portland cement concrete (PCC), including the mix design and the : materials used, the quality of construction, and the environment. Durability is not an intrinsic property of the concrete, but : i...

  12. Factors influencing chemical durability of nuclear waste glasses

    International Nuclear Information System (INIS)

    Feng, Xiangdong; Bates, J.K.

    1993-01-01

    A short summary is given of our studies on the major factors that affect the chemical durability of nuclear waste glasses. These factors include glass composition, solution composition, SA/V (ratio of glass surface area to the volume of solution), radiation, and colloidal formation. These investigations have enabled us to gain a better understanding of the chemical durability of nuclear waste glasses and to accumulate.a data base for modeling the long-term durability of waste glass, which will be used in the risk assessment of nuclear waste disposal. This knowledge gained also enhances our ability to formulate optimal waste glass compositions

  13. Decoration and durability

    DEFF Research Database (Denmark)

    Riisberg, Vibeke; Munch, Anders V.

    2015-01-01

    Throughout the scales of design there has been an exploding interest in the ornament that seems to be fuelled by different kinds of digital technology and media from CAD to digital printing in both 2D and 3D. In architecture and industrial design, it is discussed as a “return of ornament” because...... from fashion and tableware to archi- tecture and link ornamentation to the aesthetics of durability....

  14. Durability of critical infrastructures

    OpenAIRE

    Raluca Pascu; Ramiro Sofronie

    2011-01-01

    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 thr...

  15. Decoration and Durability

    DEFF Research Database (Denmark)

    Riisberg, Vibeke; Munch, Anders V.

    2015-01-01

    Throughout the scales of design there has been an exploding interest in the ornament that seems to be fuelled by different kinds of digital technology and media from CAD to digital printing in both 2D and 3D. In architecture and industrial design it is discussed as a Return of ornament, because...... appropriate or not. This leads us to suggest an array of parameters that points out different situations and meanings of ornamentation: Product categories, Durability of materials, Styles, Aesthetic experience, Emotional attachment and Historical references. We discuss these parameters in cases from fashion...

  16. Effects of Irradiation on Albite's Chemical Durability.

    Science.gov (United States)

    Hsiao, Yi-Hsuan; La Plante, Erika Callagon; Krishnan, N M Anoop; Le Pape, Yann; Neithalath, Narayanan; Bauchy, Mathieu; Sant, Gaurav

    2017-10-19

    Albite (NaAlSi 3 O 8 ), a framework silicate of the plagioclase feldspar family and a common constituent of felsic rocks, is often present in the siliceous mineral aggregates that compose concrete. When exposed to radiation (e.g., in the form of neutrons) in nuclear power plants, the crystal structure of albite can undergo significant alterations. These alterations may degrade its chemical durability. Indeed, careful examinations of Ar + -implanted albite carried out using Fourier transform infrared spectroscopy (FTIR) and molecular dynamics simulations show that albite's crystal structure, upon irradiation, undergoes progressive disordering, resulting in an expansion in its molar volume (i.e., a reduction of density) and a reduction in the connectivity of its atomic network. This loss of network connectivity (i.e., rigidity) results in an enhancement of the aqueous dissolution rate of albite-measured using vertical scanning interferometry (VSI) in alkaline environments-by a factor of 20. This enhancement in the dissolution rate (i.e., reduction in chemical durability) of albite following irradiation has significant impacts on the durability of felsic rocks and of concrete containing them upon their exposure to radiation in nuclear power plant (NPP) environments.

  17. 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

  18. Durability Evaluation of Superconducting Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Akihiko; Ogata, Masafumi; Nakauchi, Masahiko; Asahara, Tetsuo; Herai, Toshiki; Nishikawa, Yoichi

    2006-06-01

    It is one of the most essential things to verify the durability of devices and components of JR-Maglev system to realize the system into the future inauguration. Since the load requirements were insufficient in terms of the durability under vibrations under mere running tests carried out on Yamanashi Maglev Test Line hereinafter referred to YMTL, we have developed supplemental method with bench tests. Superconducting magnets hereinafter referred to SCM as used in the experimental running for the last seven years on the YMTL were brought to Kunitachi Technical Research Institute; we conducted tests to evaluate the durability of SCM up to a period of the service life in commercial use. The test results have indicated that no irregularity in each part of SCM proving that SCM are sufficiently durable for the practical application.

  19. Durability Evaluation of Superconducting Magnets

    International Nuclear Information System (INIS)

    Inoue, Akihiko; Ogata, Masafumi; Nakauchi, Masahiko; Asahara, Tetsuo; Herai, Toshiki; Nishikawa, Yoichi

    2006-01-01

    It is one of the most essential things to verify the durability of devices and components of JR-Maglev system to realize the system into the future inauguration. Since the load requirements were insufficient in terms of the durability under vibrations under mere running tests carried out on Yamanashi Maglev Test Line hereinafter referred to YMTL, we have developed supplemental method with bench tests. Superconducting magnets hereinafter referred to SCM as used in the experimental running for the last seven years on the YMTL were brought to Kunitachi Technical Research Institute; we conducted tests to evaluate the durability of SCM up to a period of the service life in commercial use. The test results have indicated that no irregularity in each part of SCM proving that SCM are sufficiently durable for the practical application

  20. Temperature induced effects on the durability of MR fluids

    International Nuclear Information System (INIS)

    Wiehe, A; Maas, J; Kieburg, C

    2013-01-01

    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.

  1. Durability of air lime mortar

    DEFF Research Database (Denmark)

    Nielsen, Anders

    2016-01-01

    This contribution deals with the physical and chemical reasons why pure air lime mortars used in masonry of burned bricks exposed to outdoor climate have shown to be durable from the Middle Ages to our days. This sounds strange in modern times where pure air lime mortars are regarded as weak...... materials, which are omitted from standards for new masonry buildings, where use of hydraulic binders is prescribed. The reasons for the durability seam to be two: 1. The old mortars have high lime contents. 2. The carbonation process creates a pore structure with a fine pored outer layer and coarser pores...

  2. Durability of building joint sealants

    Science.gov (United States)

    Christopher C. White; Kar Tean Tan; Donald L. Hunston; R. Sam Williams

    2009-01-01

    Predicting the service life of building joint sealants exposed to service environments in less than real time has been a need of the sealant community for many decades. Despite extensive research efforts to design laboratory accelerated tests to duplicate the failure modes occurring in field exposures, little success has been achieved using conventional durability...

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

    International Nuclear Information System (INIS)

    Ellison, A.J.G.; Mazer, J.J.; Ebert, W.L.

    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

  4. Compositional threshold for Nuclear Waste Glass Durability

    International Nuclear Information System (INIS)

    Kruger, Albert A.; Farooqi, Rahmatullah; Hrma, Pavel R.

    2013-01-01

    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

    1996-01-01

    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 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.

  7. Chemical durability of silicoborate glasses

    International Nuclear Information System (INIS)

    Nieto, M.I.; Rodriguez, M.A.; Rubio, J.; Fernandez, A.; Oteo, J.L.

    1987-01-01

    A general view of the durability in silicoborate glasses is presented with more emphasis on the etching factors (chemical composition, lattice structure, pH...) the techniques used for this study and the experimental results. Likewise, the research presently developed in this area at the Instituto de Ceramica y Vidrio, CSIC, is related to the applications. Future research in this field is also mentioned. (author) 15 figs

  8. ICP experiments more durable pavements

    International Nuclear Information System (INIS)

    Carta Petrolera

    1994-01-01

    A new asphalts technology that will make more durable the pavement in the highways and roads of the cities of Colombia investigates the Colombian Institute of the Petroleum ICP. The project that will have important incidence in the solution of one of the main problems in the roads of cities like Bogota, is only one of the 35 investigation programs and application of new technologies that with relationship to the sector of the hydrocarbons and its influence branches the ICP advances. The investigation looks for to elevate the current average of useful life of the pavements, with that it would be reached a standard that has the developed countries in this field

  9. Estimating Durability of Reinforced Concrete

    Science.gov (United States)

    Varlamov, A. A.; Shapovalov, E. L.; Gavrilov, V. B.

    2017-11-01

    In this article we propose to use the methods of fracture mechanics to evaluate concrete durability. To evaluate concrete crack resistance characteristics of concrete directly in the structure in order to implement the methods of fracture mechanics, we have developed special methods. Various experimental studies have been carried out to determine the crack resistance characteristics and the concrete modulus of elasticity during its operating. A comparison was carried out for the results obtained with the use of the proposed methods and those obtained with the standard methods for determining the concrete crack resistance characteristics.

  10. 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.

  11. 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.

  12. 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,...

  13. Durability of Self Compacting Concrete

    International Nuclear Information System (INIS)

    Benmarce, A.; Boudjehem, H.; Bendjhaiche, R.

    2011-01-01

    Self compacting concrete (SCC) seem to be a very promising materials for construction thanks to their properties in a fresh state. Studying of the influence of the parameters of specific designed mixes to their mechanical, physical and chemical characteristics in a state hardened is an important stage so that it can be useful for new-to-the-field researchers and designers (worldwide) beginning studies and work involving self compacting concrete. The objective of this research is to study the durability of self compacting concrete. The durability of concrete depends very much on the porosity; the latter determines the intensity of interactions with aggressive agents. The pores inside of concrete facilitate the process of damage, which began generally on the surface. We are interested to measure the porosity of concrete on five SCC with different compositions (w/c, additives) and vibrated concrete to highlight the influence of the latter on the porosity, thereafter on the compressive strength and the transfer properties (oxygen permeability, chloride ion diffusion, capillary absorption). (author)

  14. Durable crystalline Si photovoltaic modules based on silicone-sheet encapsulants

    Science.gov (United States)

    Hara, Kohjiro; Ohwada, Hiroto; Furihata, Tomoyoshi; Masuda, Atsushi

    2018-02-01

    Crystalline Si photovoltaic (PV) modules were fabricated with sheets of poly(dimethylsiloxane) (silicone) as an encapsulant. The long-term durability of the silicone-encapsulated PV modules was experimentally investigated. The silicone-based modules enhanced the long-term durability against potential-induced degradation (PID) and a damp-heat (DH) condition at 85 °C with 85% relative humidity (RH). In addition, we designed and fabricated substrate-type Si PV modules based on the silicone encapsulant and an Al-alloy plate as the substratum, which demonstrated high impact resistance and high incombustible performance. The high chemical stability, high volume resistivity, rubber-like elasticity, and incombustibility of the silicone encapsulant resulted in the high durability of the modules. Our results indicate that silicone is an attractive encapsulation material, as it improves the long-term durability of crystalline Si PV modules.

  15. Durability as integral characteristic of concrete

    Science.gov (United States)

    Suleymanova, L. A.; Pogorelova, I. A.; Suleymanov, K. A.; Kirilenko, S. V.; Marushko, M. V.

    2018-03-01

    The carried-out research provides insight into the internal bonds energy in material as the basis of its durability, deformability, integrity and resistance to different factors (combined effects of external loadings and (or) environment), into the limits of technical possibilities, durability and physical reality of the process of concrete deterioration, which allows designing reliable and cost-effective ferroconcrete constructions for different purposes.

  16. Reliability and durability in solar energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Godolphin, D.

    1982-10-01

    The reliability and durability in solar energy systems for residential buildings is discussed. It is concluded that although strides have been made in design and manufacturing over the past years, the reliability and durability of the equipment depends on the proper installation. (MJF)

  17. 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.

  18. Durability of aircraft composite materials

    Science.gov (United States)

    Dextern, H. B.

    1982-01-01

    Confidence in the long term durability of advanced composites is developed through a series of flight service programs. Service experience is obtained by installing secondary and primary composite components on commercial and military transport aircraft and helicopters. Included are spoilers, rudders, elevators, ailerons, fairings and wing boxes on transport aircraft and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on helicopters. Materials included in the evaluation are boron/epoxy, Kevlar/epoxy, graphite/epoxy and boron/aluminum. Inspection, maintenance, and repair results for the components in service are reported. The effects of long term exposure to laboratory, flight, and outdoor environmental conditions are reported for various composite materials. Included are effects of moisture absorption, ultraviolet radiation, and aircraft fuels and fluids.

  19. Self-curing concrete types; water retention and durability

    Directory of Open Access Journals (Sweden)

    Magda I. Mousa

    2015-09-01

    This study was carried out to compare among concretes without or with silica fume (SF along with chemical type of shrinkage reducing admixture, polyethylene-glycol (Ch, and leca as self-curing agents for water retention even at elevated temperature (50 °C and their durability. The cement content of 400 kg/m3, silica fume of 15% by weight of cement, polyethylene-glycol of 2% by weight of cement, pre-saturated lightweight aggregate (leca 15% by volume of sand and water with Ch/binder ratio of 0.4 were selected in this study. Some of the physical and mechanical properties were determined periodically up to 28 days in case of exposure to air curing in temperature of (25 °C and (50 °C while up to 6 months of exposure to 5% of carbon dioxide and wet/dry cycles in 8% of sodium chloride for durability study. The concrete mass loss and the volumetric water absorption were measured, to evaluate the water retention of the investigated concretes. Silica fume concrete either without or with Ch gave the best results under all curing regimes; significant water retention and good durability properties.

  20. Integrated durability process in product development

    International Nuclear Information System (INIS)

    Pompetzki, M.; Saadetian, H.

    2002-01-01

    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)

  1. 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.

  2. Increase of cyclic durability of pressure vessels

    International Nuclear Information System (INIS)

    Vorona, V.A.; Zvezdin, Yu.I.

    1980-01-01

    The durability of multilayer pressure vessels under cyclic loading is compared with single-layer vessels. The relative conditional durability is calculated taking into account the assumption on the consequent destruction of layers and viewing a vessel wall as an indefinite plate. It is established that the durability is mainly determined by the number of layers and to a lesser degree depends on the relative size of the defect for the given layer thickness. The advantage of the multilayer vessels is the possibility of selecting layer materials so that to exclude the effect of agressive corrosion media on the strength [ru

  3. Quick test for durability factor estimation.

    Science.gov (United States)

    2010-03-01

    The Missouri Department of Transportation (MoDOT) is considering the use of the AASHTO T 161 Durability Factor (DF) as an endresult : performance specification criterion for evaluation of paving concrete. However, the test method duration can exceed ...

  4. International Conference on Durability of Critical Infrastructure

    CERN Document Server

    Cherepetskaya, Elena; Pospichal, Vaclav

    2017-01-01

    This book presents the proceedings of the International Conference on Durability of Critical Infrastructure. Monitoring and Testing held in Satov, Czech Republic from 6 to 9 December 2016. It discusses the developments in the theoretical and practical aspects in the fields of Safety, Sustainability and Durability of the Critical Infrastructure. The contributions are dealing with monitoring and testing of structural and composite materials with a new methods for their using for protection and prevention of the selected objects.

  5. 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.

  6. A generalized definition for waste form durability

    International Nuclear Information System (INIS)

    Fanning, T. H.; Bauer, T. H.; Morris, E. E.; Wigeland, R. A.

    2002-01-01

    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

  7. Durability analysis of gneiss using wear resistance

    Directory of Open Access Journals (Sweden)

    José Luiz Ernandes Dias Filho

    2014-01-01

    Full Text Available This paper presents a study conducted in gneiss in Santo Antonio de Pádua, RJ, BR, including durability analysis of the rock using slake durability test. Rocks in the region of Pádua are mostly used for ornamental purposes. A lab equipment was developed to evaluate the influence of rotation in the test, allowing for the speed variation of 7 RPM to 238 RPM. This study could be implemented in a wide variety of rock materials, targeting them according to their lifetime in the project. With variation of the wear levels, increasing weight loss was observed until the inertia moment in which the sample holds to the machine wall. The results indicate an increase in linear mass loss. These procedures allow a more precise analysis of durability than can be applied in different different regions of the world.

  8. Pyramiding for Resistance Durability: Theory and Practice.

    Science.gov (United States)

    Mundt, Chris

    2018-04-12

    Durable disease resistance is a key component of global food security, and combining resistance genes into "pyramids" is an important way to increase durability of resistance. The mechanisms by which pyramids impact durability are not well known. The traditional view of resistance pyramids considers the use of major resistance gene (R-gene) combinations deployed against pathogens that are primarily asexual. Interestingly, published examples of the successful use of pyramids in the traditional sense are rare. In contrast, most published descriptions of durable pyramids in practice are for cereal rusts, and tend to indicate an association between durability and cultivars combining major R-genes with incompletely expressed, adult plant resistance genes. Pyramids have been investigated experimentally for a diversity of pathogens, and many reduce disease levels below that of the single best gene. Resistance gene combinations have been identified through phenotypic reactions, molecular markers, and challenge against effector genes. As resistance genes do not express equally in all genetic backgrounds, however, a combination of genetic information and phenotypic analyses provide the ideal scenario for testing of putative pyramids. Not all resistance genes contribute equally to pyramids, and approaches have been suggested to identify the best genes and combinations of genes for inclusion. Combining multiple resistance genes into a single plant genotype quickly is a challenge that is being addressed through alternative breeding approaches, as well as through genomics tools such as resistance gene cassettes and gene editing. Experimental and modeling tests of pyramid durability are in their infancy, but have promise to help direct future studies of pyramids. Several areas for further work on resistance gene pyramids are suggested.

  9. 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.

  10. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Nielsen, Laila

    1997-01-01

    (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...

  11. 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. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. The prospective buyer of consumer durables

    NARCIS (Netherlands)

    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

  13. Durable Glass For Thousands Of Years

    International Nuclear Information System (INIS)

    Jantzen, C.

    2009-01-01

    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 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.

  14. 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.

  15. Enhancing composite durability : using thermal treatments

    Science.gov (United States)

    Jerrold E. Winandy; W. Ramsay Smith

    2007-01-01

    The use of thermal treatments to enhance the moisture resistance and aboveground durability of solid wood materials has been studied for years. Much work was done at the Forest Products Laboratory in the last 15 years on the fundamental process of both short-and long-term exposure to heat on wood materials and its interaction with various treatment chemicals. This work...

  16. 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... problems, deterioration in spark plug life, increase in carburetor or combustion chamber deposits, or..., then a durability run may be made as described in subpart E, in which fuel economy and exhaust...

  17. 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.

  18. Durability of wood-plastic composite lumber

    Science.gov (United States)

    Rebecca E. Ibach

    2010-01-01

    Wood-plastic composite (WPC) lumber has been marketed as a low-maintenance, high-durability product. Retail sales in the United States were slightly less than $1 billion in 2008. Applications include docking, railing, windows, doors, fencing, siding, moldings, landscape timbers, car interior parts, and furniture. The majority of these products are used outdoors and...

  19. DURABILITY OF FLEXIBLE PAVEMENTS: A CASE STUDY OF ...

    African Journals Online (AJOL)

    user

    years, ranking, predominant factors affecting pavement durability and the estimate of durability. In this regard .... subgrade soil into the base course and provide the drainage of ..... [3] Oguara T. M. “A management model for road infrastructure ...

  20. 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.)

  1. The influence of humidity on strengths and durability of light guides fibers

    International Nuclear Information System (INIS)

    Karimov, S.N.; Kuksenko, V.S.; Sultonov, U.; Abdumanonov, A.; Shamsidinov, M.I.

    1993-01-01

    Humidity influence on durability and light water durability fibres is studied are studied in this article. Humidity energy under influence of process destruction decreases activity, durability and durability decreases is shown

  2. Monetary Policy with Sectoral Linkages and Durable Goods

    DEFF Research Database (Denmark)

    Petrella, Ivan; Rossi, Raffaele; Santoro, Emiliano

    We study the normative implications of a New Keynesian model featuring intersectoral trade of intermediate goods between two sectors that produce durables and non-durables. The interplay between durability and sectoral production linkages fundamentally alters the intersectoral stabilization trade....... 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 schedules...

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

    Energy Technology Data Exchange (ETDEWEB)

    Yandrasits, Michael A.

    2008-02-15

    the same. (6) Through the use of statistical lifetime analysis methods, it is possible to develop new MEAs with predicted durability approaching the DOE 2010 targets. (7) A segmented cell was developed that extend the resolution from ~ 40 to 121 segments for a 50cm2 active area single cell which allowed for more precise investigation of the local phenomena in a operating fuel cell. (8) The single cell concept was extended to a fuel size stack to allow the first of its kind monitoring and mapping of an operational fuel cell stack. An internal check used during this project involved evaluating the manufacturability of any new MEA component. If a more durable MEA component was developed in the lab, but could not be scaled-up to ‘high speed, high volume manufacturing’, then that component was not selected for the final MEA-fuel cell system demonstration. It is the intent of the team to commercialize new products developed under this project, but commercialization can not occur if the manufacture of said new components is difficult or if the price is significantly greater than existing products as to make the new components not cost competitive. Thus, the end result of this project is the creation of MEA and fuel cell system technology that is capable of meeting the DOEs 2010 target of 40,000 hours for stationary fuel cell systems (although this lifetime has not been demonstrated in laboratory or field testing yet) at a cost that is economically viable for the developing fuel cell industry. We have demonstrated over 2,000 hours of run time for the MEA and system developed under this project.

  4. The chemical durability of alkali aluminosilicate glasses

    International Nuclear Information System (INIS)

    Tait, J.C.; Mandolesi, D.L.

    1983-09-01

    The aqueous durabilities of a series of glasses based on the sodium aluminosilicate system (Na 2 O-Al 2 O 3 -SiO 2 ) have been studied. The effects of molecular substitution of K 2 O or CaO for Na 2 O, and B 2 O 3 for Al 2 O 3 have been investigated. The temperature dependence of leaching in the Na 2 O-B 2 O 3 -Al 2 O 3 -SiO 2 system was studied with glasses containing 2 wt percent simulated UO 2 fuel recycle waste. The results confirm that aluminosilicate glasses are more durable than their borosilicate counterparts. The leaching results are explained in terms of glass structure and bonding, and a general leaching mechanism for aluminosilicate glasses is presented

  5. Durable terrestrial bedrock predicts submarine canyon formation

    Science.gov (United States)

    Smith, Elliot; Finnegan, Noah J.; Mueller, Erich R.; Best, Rebecca J.

    2017-01-01

    Though submarine canyons are first-order topographic features of Earth, the processes responsible for their occurrence remain poorly understood. Potentially analogous studies of terrestrial rivers show that the flux and caliber of transported bedload are significant controls on bedrock incision. Here we hypothesize that coarse sediment load could exert a similar role in the formation of submarine canyons. We conducted a comprehensive empirical analysis of canyon occurrence along the West Coast of the contiguous United States which indicates that submarine canyon occurrence is best predicted by the occurrence of durable crystalline bedrock in adjacent terrestrial catchments. Canyon occurrence is also predicted by the flux of bed sediment to shore from terrestrial streams. Surprisingly, no significant correlation was observed between canyon occurrence and the slope or width of the continental shelf. These findings suggest that canyon incision is promoted by greater yields of durable terrestrial clasts to the shore.

  6. Mankiw's Puzzle on Consumer Durables: A Misspecification

    OpenAIRE

    Tam Bang Vu

    2005-01-01

    Mankiw (1982) shows that consumer durables expenditures should follow a linear ARMA(1,1) process, but the data analyzed supports an AR(1) process instead; thus, a puzzle. In this paper, we employ a more general utility function than Mankiw's quadratic one. Further, the disturbance and depreciation rate are respecified, respectively, as multiplicative and stochastic. The analytical consequence is a nonlinear ARMA(infinity,1) process, which implies that the linear ARMA(1,1) is a misspecificatio...

  7. OPTIONS D'INTENSIFICATION DURABLE DES CULTURES ...

    African Journals Online (AJOL)

    (Received 14 August, 2001 ; accepted 10 May, 2002) RÉSUMÉ Pour intensifier de manière durable les cultures vivrières dans les zones de terres de barre dégradées au sud du Togo, plusieurs options ont été évaluées avec les paysans. Grâce à des entretiens collectifs de type participatif, sept différents groupes ...

  8. Durability 2007. Injection grout investigations. Background description

    International Nuclear Information System (INIS)

    Orantie, K.; Kuosa, H.

    2008-12-01

    The aim of this project was to evaluate the durability risks of injection grouts. The investigations were done with respect to the application conditions, materials and service life requirements at the ONKALO underground research facility. The study encompassed injection grout mixtures made of ultrafine cement with and without silica fume. Some of the mixtures hade a low pH and thus a high silica fume content. The project includes a background description on durability literature, laboratory testing programme, detailed analysis of results and recommendations for selecting of ideal grout mixtures. The background description was made for the experimental study of low-pH and reference rock injection grouts as regards pore- and microstructure, strength, shrinkage/swelling and thus versatile durability properties. A summary of test methods is presented as well as examples, i.e. literature information or former test results, of expected range of results from the tests. Also background information about how the test results correlate to other material properties and mix designs is presented. Besides the report provides basic information on the pore structure of cement based materials. Also the correlation between the pore structure of cement based materials and permeability is shortly discussed. The test methods included in the background description are compressive strength, measurement of bulk drying, autogenous and chemical shrinkage and swelling, hydraulic conductivity / permeability, capillary water uptake test, mercury intrusion porosimetry (MIP) and thin section analysis. Three main mixtures with water-binder ratio of 0.8, 1.0 and 1.4 and silica fume content of 0, 15 and 40% were studied in the laboratory. Besides two extra mixtures were studied to provide additional information about the effect of varying water-dry-material ratio and silica fume content on durability. The evaluation of water tightness based on water permeability coefficient and micro cracking was

  9. 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.

  10. Durability of heavyweight concrete containing barite

    International Nuclear Information System (INIS)

    Binici, Hanifi

    2010-01-01

    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.)

  11. 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.

  12. 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.

  13. 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.

  14. Experimental Investigation of the Mechanical and Durability Properties of Crumb Rubber Concrete.

    Science.gov (United States)

    Liu, Hanbing; Wang, Xianqiang; Jiao, Yubo; Sha, Tao

    2016-03-07

    Recycling waste tire rubber by incorporating it into concrete has become the preferred solution to dispose of waste tires. In this study, the effect of the volume content of crumb rubber and pretreatment methods on the performances of concrete was evaluated. Firstly, the fine aggregate and mixture were partly replaced by crumb rubber to produce crumb rubber concrete. Secondly, the mechanical and durability properties of crumb rubber concrete with different replacement forms and volume contents had been investigated. Finally, the crumb rubber after pretreatment by six modifiers was introduced into the concrete mixture. Corresponding tests were conducted to verify the effectiveness of pretreatment methods as compared to the concrete containing untreated crumb rubber. It was observed that the mechanical strength of crumb rubber concrete was reduced, while durability was improved with the increasing of crumb rubber content. 20% replacement of fine aggregate and 5% replacement of the total mixture exhibited acceptable properties for practical applications. In addition, the results indicated that the modifiers had a positive impact on the mechanical and durability properties of crumb rubber concrete. It avoided the disadvantage of crumb rubber concrete having lower strength and provides a reference for the production of modified crumb rubber concrete.

  15. Experimental Investigation of the Mechanical and Durability Properties of Crumb Rubber Concrete

    Directory of Open Access Journals (Sweden)

    Hanbing Liu

    2016-03-01

    Full Text Available Recycling waste tire rubber by incorporating it into concrete has become the preferred solution to dispose of waste tires. In this study, the effect of the volume content of crumb rubber and pretreatment methods on the performances of concrete was evaluated. Firstly, the fine aggregate and mixture were partly replaced by crumb rubber to produce crumb rubber concrete. Secondly, the mechanical and durability properties of crumb rubber concrete with different replacement forms and volume contents had been investigated. Finally, the crumb rubber after pretreatment by six modifiers was introduced into the concrete mixture. Corresponding tests were conducted to verify the effectiveness of pretreatment methods as compared to the concrete containing untreated crumb rubber. It was observed that the mechanical strength of crumb rubber concrete was reduced, while durability was improved with the increasing of crumb rubber content. 20% replacement of fine aggregate and 5% replacement of the total mixture exhibited acceptable properties for practical applications. In addition, the results indicated that the modifiers had a positive impact on the mechanical and durability properties of crumb rubber concrete. It avoided the disadvantage of crumb rubber concrete having lower strength and provides a reference for the production of modified crumb rubber concrete.

  16. Microcracking and durability of high strength concretes

    International Nuclear Information System (INIS)

    Yssorche, M.P.

    1995-07-01

    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)

  17. Durable fear memories require PSD-95

    Science.gov (United States)

    Fitzgerald, Paul J.; Pinard, Courtney R.; Camp, Marguerite C.; Feyder, Michael; Sah, Anupam; Bergstrom, Hadley; Graybeal, Carolyn; Liu, Yan; Schlüter, Oliver; Grant, Seth G.N.; Singewald, Nicolas; Xu, Weifeng; Holmes, Andrew

    2014-01-01

    Traumatic fear memories are highly durable but also dynamic, undergoing repeated reactivation and rehearsal over time. While overly persistent fear memories underlie anxiety disorders such as posttraumatic stress disorder, the key neural and molecular mechanisms underlying fear memory durability remain unclear. Post-synaptic density 95 (PSD-95) is a synaptic protein regulating glutamate receptor anchoring, synaptic stability and certain types of memory. Employing a loss-of-function mutant mouse lacking the guanylate kinase domain of PSD-95 (PSD-95GK), 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 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-95GK mice to retrieve remote cued fear memories was associated with hypoactivation of the infralimbic cortex (IL) (not anterior cingulate (ACC) or prelimbic cortex), reduced IL single-unit firing and bursting, and attenuated IL gamma and theta oscillations. Adeno-associated PSD-95 virus-mediated knockdown in the IL, not 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

  18. Durability Testing of Idlers for Belt Conveyors

    Directory of Open Access Journals (Sweden)

    Andrzej Pytlik

    2013-01-01

    On the basis of the durability tests carried out on both of these idlers it can be concluded that the applied research methodology describes the test conditions of idlers, in a manner as close as possible to their actual operational conditions, which were subject to a variety of factors for a total time of 116 hours, they included: dust, water, loads and variable rotational speed. This methodology allowed us to determine, even at the stage of laboratory tests, the suitability of a particular idler to certain operational conditions.

  19. 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.

  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. Durability of capital goods: taxes and market structure

    Energy Technology Data Exchange (ETDEWEB)

    Raviv, A [Carnegie-Mellon Univ., Pittsburgh; Zemel, E

    1977-04-01

    This paper examines the durability of capital goods produced under different market structures when tax considerations are included. Since investment tax credit and depreciation allowances are realized by the owner of the durable good, the durability of products produced by an industry which sells its output differs from that of an industry which rents. For each of these two commercial forms, both monopolistic and competitive market structure are considered. Potential gains from different forms of regulation are discussed.

  2. The household decision making process in replacement of durable goods

    OpenAIRE

    Marell Molander, Agneta

    1998-01-01

    As durables are essential in many households, the level of ownership is high and, due to the high degree of penetration, a vast proportion of the current sales are replacement purchases. Even though a lot of research attention has been paid to decision making and decision processes many models are oriented towards non-durable goods and although a majority of purchases of many durable goods are replacements, few studies seem to make a distinction between a replacement purchase decision and a d...

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

    OpenAIRE

    Polato e Fava, Ana Claudia; 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...

  4. Evaluation of models of waste glass durability

    International Nuclear Information System (INIS)

    Ellison, A.

    1995-01-01

    The main variable under the control of the waste glass producer is the composition of the glass; thus a need exists to establish functional relationships between the composition of a waste glass and measures of processability, product consistency, and durability. Many years of research show that the structure and properties of a glass depend on its composition, so it seems reasonable to assume that there also is relationship between the composition of a waste glass and its resistance to attack by an aqueous solution. Several models have been developed to describe this dependence, and an evaluation their predictive capabilities is the subject of this paper. The objective is to determine whether any of these models describe the ''correct'' functional relationship between composition and corrosion rate. A more thorough treatment of the relationships between glass composition and durability has been presented elsewhere, and the reader is encouraged to consult it for a more detailed discussion. The models examined in this study are the free energy of hydration model, developed at the Savannah River Laboratory, the structural bond strength model, developed at the Vitreous State Laboratory at the Catholic University of America, and the Composition Variation Study, developed at Pacific Northwest Laboratory

  5. Durability of cement and geopolimer composites

    Science.gov (United States)

    Błaszczyński, T.; Król, M.

    2017-10-01

    Concrete structures are constantly moving in the direction of improving the durability. This main feature depends on many factors, which are the composition of concrete mix, the usage of additives and admixtures and the place, where material will work and carry the load. The introduction of new geopolymer binders for geopolymer structures adds a new aspect that is type of used activator. This substance with strongly alkaline reaction is divided because of the physical state, the alkaline degree and above all the chemical composition. Taking into account, that at present the geopolymer binders are made essentially from waste materials or by products from the combustion of coal or iron ore smelting, unambiguous determination of the effect of the activator on the properties of the geopolymer material requires a number of trials, researches and observation. This paper shows the influence of the most alkaline activators on the basic parameters of the durability of geopolymer binders. In this study there were used a highly alkaline hydroxides, water glasses and granules, which are waste materials in a variety of processes taking place in a chemical plants. As the substrate of geopolymer binders there were used fly ash which came from coal and high calcium ash from the burning of lignite.

  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. Durability of coconut shell powder (CSP) concrete

    Science.gov (United States)

    Leman, A. S.; Shahidan, S.; Senin, M. S.; Shamsuddin, S. M.; Anak Guntor, N. A.; Zuki, S. S. Mohd; Khalid, F. S.; Azhar, A. T. S.; Razak, N. H. S.

    2017-11-01

    The rising cost of construction in developing countries like Malaysia has led concrete experts to explore alternative materials such as coconut shells which are renewable and possess high potential to be used as construction material. Coconut shell powder in varying percentages of1%, 3% and 5% was used as filler material in concrete grade 30 and evaluated after a curing period of 7 days and 28days respectively. Compressive strength, water absorption and carbonation tests were conducted to evaluate the strength and durability of CSP concrete in comparison with normal concrete. The test results revealed that 1%, 3% and 5% of CSP concrete achieved a compressive strength of 47.65 MPa, 45.6 MPa and 40.55% respectively. The rate of water absorption of CSP concrete was recorded as 3.21%, 2.47%, and 2.73% for 1%, 3% and 5% of CSP concrete respectively. Although CSP contained a carbon composition of 47%, the carbonation test showed that CSP no signs of carbon were detected inside the concrete. To conclude, CSP offers great prospects as it demonstrated relatively high durability as a construction material.

  8. Durability of thin-walled concrete structures

    International Nuclear Information System (INIS)

    Salomon, M.; Gallias, J.L.

    1991-01-01

    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 [fr

  9. Durability of high performance concrete in seawater

    International Nuclear Information System (INIS)

    Amjad Hussain Memon; Salihuddin Radin Sumadi; Rabitah Handan

    2000-01-01

    This paper presents a report on the effects of blended cements on the durability of high performance concrete (HPC) in seawater. In this research the effect of seawater was investigated. The specimens were initially subjected to water curing for seven days inside the laboratory at room temperature, followed by seawater curing exposed to tidal zone until testing. In this study three levels of cement replacement (0%, 30% and 70%) were used. The combined use of chemical and mineral admixtures has resulted in a new generation of concrete called HPC. The HPC has been identified as one of the most important advanced materials necessary in the effort to build a nation's infrastructure. HPC opens new opportunities in the utilization of the industrial by-products (mineral admixtures) in the construction industry. As a matter of fact permeability is considered as one of the fundamental properties governing the durability of concrete in the marine environment. Results of this investigation indicated that the oxygen permeability values for the blended cement concretes at the age of one year are reduced by a factor of about 2 as compared to OPC control mix concrete. Therefore both blended cement concretes are expected to withstand in the seawater exposed to tidal zone without serious deterioration. (Author)

  10. Durable and Robust Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Hjalmarsson, Per; Knibbe, Ruth; Hauch, Anne

    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......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...... for use within the CHP (Combined Heat and Power) market segment with stationary power plants in the range 1 – 250 kWe in mind. Lowered operation temperature is considered a good way to improve the stack durability since corrosion of the interconnect plates in a stack is lifetime limiting at T > 750 °C...

  11. 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.)

  12. 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.)

  13. 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.)

  14. 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.)

  15. Bill asserting the national commitment for the environment (declared urgency), text from the commission of economy, sustainable development and town and country planning; Projet de Loi portant engagement national pour l'environnement (urgence declaree), Texte de la Commission de L'Economie, du Developpement Durable et de L'Amenagement du Territoire

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-15

    The bill asserting the French national commitment for the environment (also named 'Grenelle 2') is considered as the juridical tool-box of the French environmental policy. It confirms, strengthens, and concretizes the objectives defined by the Grenelle 1 law. The main dispositions of the bill concern the following domains: settlement and urbanism with the improvement of the energy efficiency, energy conservation and life-cycle of buildings; transports with the development of sustainable transportation systems; energy with the creation of regional climate, air and energy schemes with the aim of developing renewable energies (with some restrictions concerning wind power) and reducing CO{sub 2} emissions; biodiversity with the creation of ecological pathways between protected areas for the migration of flora and fauna species; environment and waste management with the reinforcement of measures for the abatement of environmental pollutant effects. Among the numerous dispositions involving more than 20 codes (urbanism, environment, buildings etc..) one concerns the progressive implementation of a 'carbon price' index taking into account the greenhouse gas emission costs during the whole life cycle of a product, another one concerns the monitoring of indoor air quality in public buildings. This document is the text of the bill as prepared by the Commission of economy, sustainable development and town and country planning. (J.S.)

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

    International Nuclear Information System (INIS)

    Thomasson, J.

    1999-01-01

    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

  17. Influence Of Density On The Durabilities Of Three Ghanaian Timbers ...

    African Journals Online (AJOL)

    Review of factors influencing wood durability shows although density varies depending on trunk position, its role appears controversial for many timber species. Thus, for the first time, the influence of density on the durability of three Ghanaian timbers (Nauclea diderrichii (de Wild.) Merr., Nesogordonia papaverifera (A. Chev ...

  18. Adhesives for Achieving Durable Bonds with Acetylated Wood

    Science.gov (United States)

    Charles Frihart; Rishawn Brandon; James Beecher; Rebecca Ibach

    2017-01-01

    Acetylation of wood imparts moisture durability, decay resistance, and dimensional stability to wood; however, making durable adhesive bonds with acetylated wood can be more difficult than with unmodified wood. The usual explanation is that the acetylated surface has fewer hydroxyl groups, resulting in a harder-to-wet surface and in fewer hydrogen bonds between wood...

  19. Chemical durability of glasses containing radioactive fission product waste

    International Nuclear Information System (INIS)

    Mendel, J.E.; Ross, W.A.

    1974-04-01

    Measurements made to determine the chemical durability of glasses for disposal of radioactive waste are discussed. The term glass covers materials varying from true glass with only minute quantities of crystallites, such as insoluble RuO 2 , to quasi glass-ceramics which are mostly crystalline. Chemical durability requirements and Soxhlet extractor leach tests are discussed

  20. Effect of Unprofessional Supervision on Durability of Buildings.

    Science.gov (United States)

    Yahaghi, Javad

    2018-02-01

    The durability of buildings which depends on the nature of the supervisory system used in their construction is an important feature of the construction industry. This article tries to draw the readers' attention to the effect of untrained and unprofessional building supervisors and their unethical performance on the durability of buildings.

  1. Durable solid oxide electrolysis cells and stacks

    Energy Technology Data Exchange (ETDEWEB)

    Ming Chen

    2010-08-15

    The purpose of this project was to make a substantial contribution to development of a cost competitive electrolysis technology based on solid oxide cells. The strategy was to address what had been identified as the key issues in previous research projects. Accordingly five lines of work were carried out in the here reported project: 1) Cell and stack element testing and post test characterization to identify major degradation mechanisms under electrolysis operation. 2) Development of interconnects and coatings to allow stable electrolysis operation at approx850 deg. C or above. 3) Development of seals with reduced Si emission. 4) Development of durable SOEC cathodes. 5) Modeling. Good progress has been made on several of the planned activities. The outcome and most important achievements of the current project are listed for the five lines of the work. (LN)

  2. Cement replacement materials. Properties, durability, sustainability

    International Nuclear Information System (INIS)

    Ramezanianpour, Ali Akbar

    2014-01-01

    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.

  3. Durability of Silicate Glasses: An Historical Approach

    International Nuclear Information System (INIS)

    Farges, Francois; Etcheverry, Marie-Pierre; Haddi, Amine; Trocellier, Patrick; Curti, Enzo; Brown, Gordon E. Jr.

    2007-01-01

    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

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

    International Nuclear Information System (INIS)

    CAROL, JANTZEN

    2005-01-01

    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

  5. 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.

  6. 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).

  7. Durable bistable auxetics made of rigid solids

    Science.gov (United States)

    Shang, Xiao; Liu, Lu; Rafsanjani, Ahmad; Pasini, Damiano

    2018-02-01

    Bistable Auxetic Metamaterials (BAMs) are a class of monolithic perforated periodic structures with negative Poisson's ratio. Under tension, a BAM can expand and reach a second state of equilibrium through a globally large shape transformation that is ensured by the flexibility of its elastomeric base material. However, if made from a rigid polymer, or metal, BAM ceases to function due to the inevitable rupture of its ligaments. The goal of this work is to extend the unique functionality of the original kirigami architecture of BAM to a rigid solid base material. We use experiments and numerical simulations to assess performance, bistability and durability of rigid BAMs at 10,000 cycles. Geometric maps are presented to elucidate the role of the main descriptors of BAM architecture. The proposed design enables the realization of BAM from a large palette of materials, including elastic-perfectly plastic materials and potentially brittle materials.

  8. Durable fiber reinforced self-compacting concrete

    International Nuclear Information System (INIS)

    Corinaldesi, V.; Moriconi, G.

    2004-01-01

    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

  9. Sustainability and durability analysis of reinforced concrete structures

    Science.gov (United States)

    Horáková, A.; Broukalová, I.; Kohoutková, A.; Vašková, J.

    2017-09-01

    The article describes an assessment of reinforced concrete structures in terms of durability and sustainable development. There is a short summary of findings from the literature on evaluation methods for environmental impacts and also about corrosive influences acting on the reinforced concrete structure, about factors influencing the durability of these structures and mathematical models describing the corrosion impacts. Variant design of reinforced concrete structure and assessment of these variants in terms of durability and sustainability was performed. The analysed structure was a concrete ceiling structure of a parking house for cars. The variants differ in strength class of concrete and thickness of concrete slab. It was found that in terms of durability and sustainable development it is significantly preferable to use higher class of concrete. There are significant differences in results of concrete structures durability for different mathematical models of corrosive influences.

  10. Durability of an inorganic polymer concrete coating

    Science.gov (United States)

    Wasserman, Kenneth

    The objective of the research program reported in this thesis is to evaluate the durability of an inorganic polymer composite coating exposed to freeze/thaw cycling and wet-dry cycling. Freeze/thaw cycling is performed following ASTM D6944-09 Standard Practice for Resistance of Cured Coatings to Thermal Cycling and wet/dry cycling is performed following guidelines set forth in a thesis written by Ronald Garon at Rutgers University. For both sets of experiments, four coating mixture proportions were evaluated. The variables were: silica/alumina ratio, mixing protocol using high shear and normal shear mixing, curing temperatures of 70 and 120 degrees Fahrenheit and use of nano size constituent materials. The mix with highest silica/alumina ratio was designated as Mix 1 and mixes with lower ratios were designated as Mix 2 and Mix 3. Mix 4 had nano silica particles. Four prisms were used for each variable including control that had no coating. The performance of the coating was evaluated using adhesion strength measured using: ASTM D7234 Test Method for Pull-Off Strength of Coatings on Concrete Using Portable Adhesion Testers. Tests were performed after every five consecutive cycles of thermal conditioning and six consecutive cycles of wet-dry exposure. Results from the thermal cycling and wet-dry testing demonstrate that all coating formulations are durable. The minimum adhesion strength was 300 psi even though a relatively weak base concrete surface was chosen for the study. The weak surface was chosen to simulate aged concrete surfaces present in actual field conditions. Due to the inherent nature of the test procedure the variation in test results is high. However, based on the test results, high shear mixer and high temperature curing are not recommended. As expected nano size constituent materials provide better performance.

  11. 75 FR 51245 - Agency Information Collection Activities; Proposed Collection; Comment Request; Durable Nursery...

    Science.gov (United States)

    2010-08-19

    ... CONSUMER PRODUCT SAFETY COMMISSION [Docket No. CPSC-2010-0088] Agency Information Collection Activities; Proposed Collection; Comment Request; Durable Nursery Products Exposure Survey AGENCY: Consumer... efforts on durable infant and toddler products. The draft Durable Nursery Products Exposure Survey...

  12. The Durability and Performance of Short Fibers for a Newly Developed Alkali-Activated Binder

    Directory of Open Access Journals (Sweden)

    Henrik Funke

    2016-03-01

    Full Text Available This study reports the development of a fiber-reinforced alkali-activated binder (FRAAB with an emphasis on the performance and the durability of the fibers in the alkaline alkali-activated binder (AAB-matrix. For the development of the matrix, the reactive components granulated slag and coal fly ash were used, which were alkali-activated with a mixture of sodium hydroxide (2–10 mol/L and an aqueous sodium silicate solution (SiO2/Na2O molar ratio: 2.1 at ambient temperature. For the reinforcement of the matrix integral fibers of alkali-resistant glass (AR-glass, E-glass, basalt, and carbon with a fiber volume content of 0.5% were used. By the integration of these short fibers, the three-point bending tensile strength of the AAB increased strikingly from 4.6 MPa (no fibers up to 5.7 MPa (carbon after one day. As a result of the investigations of the alkali resistance, the AR-glass and the carbon fibers showed the highest durability of all fibers in the FRAAB-matrix. In contrast to that, the weight loss of E-glass and basalt fibers was significant under the alkaline condition. According to these results, only the AR-glass and the carbon fibers reveal sufficient durability in the alkaline AAB-matrix.

  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. Towards a durability test for washing-machines.

    Science.gov (United States)

    Stamminger, Rainer; Tecchio, Paolo; Ardente, Fulvio; Mathieux, Fabrice; Niestrath, Phoebe

    2018-04-01

    Durability plays a key role in enhancing resource conservation and contributing to waste minimization. The washing-machine product group represents a relevant case study for the development of a durability test and as a potential trigger to systematically address durability in the design of products. We developed a procedure to test the durability performance of washing-machines as a main objective of this research. The research method consisted of an analysis of available durability standards and procedures to test products and components, followed by an analysis of relevant references related to frequent failures. Finally, we defined the criteria and the conditions for a repeatable, relatively fast and relevant endurance test. The durability test considered the whole product tested under conditions of stress. A series of spinning cycles with fixed imbalanced loads was run on two washing-machines to observe failures and performance changes during the test. Even though no hard failures occurred, results clearly showed that not all washing-machines can sustain such a test without abrasion or performance deterioration. However, the attempt to reproduce the stress induced on a washing-machine by carrying out a high number of pure spinning cycles with fixed loads did not allow equal testing conditions: the actions of the control procedure regarding imbalanced loads differ from machine to machine. The outcomes of this research can be used as grounds to develop standardised durability tests and to, hence, contribute to the development of future product policy measures.

  15. Testing the durability of concrete with neutron radiography

    International Nuclear Information System (INIS)

    Beer, F.C. de; Le Roux, J.J.; Kearsley, E.P.

    2005-01-01

    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

  16. Influence of chloride admixtures on cement matrix durability

    International Nuclear Information System (INIS)

    Sheikh, I.A.; Zamorani, E.; Serrini, G.

    1989-01-01

    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 50 0 C, 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

  17. ACCELERATED METHODS FOR ESTIMATING THE DURABILITY OF PLAIN BEARINGS

    Directory of Open Access Journals (Sweden)

    Myron Czerniec

    2014-09-01

    Full Text Available The paper presents methods for determining the durability of slide bearings. The developed methods enhance the calculation process by even 100000 times, compared to the accurate solution obtained with the generalized cumulative model of wear. The paper determines the accuracy of results for estimating the durability of bearings depending on the size of blocks of constant conditions of contact interaction between the shaft with small out-of-roundedness and the bush with a circular contour. The paper gives an approximate dependence for determining accurate durability using either a more accurate or an additional method.

  18. Durability of PEM Fuel Cell Membranes

    Science.gov (United States)

    Huang, Xinyu; Reifsnider, Ken

    Durability is still a critical limiting factor for the commercialization of polymer electrolyte membrane (PEM) fuel cells, a leading energy conversion technology for powering future hydrogen fueled automobiles, backup power systems (e.g., for base transceiver station of cellular networks), portable electronic devices, etc. Ionic conducting polymer (ionomer) electrolyte membranes are the critical enabling materials for the PEM fuel cells. They are also widely used as the central functional elements in hydrogen generation (e.g., electrolyzers), membrane cell for chlor-alkali production, etc. A perfluorosulfonic acid (PFSA) polymer with the trade name Nafion® developed by DuPont™ is the most widely used PEM in chlor-alkali cells and PEM fuel cells. Similar PFSA membranes have been developed by Dow Chemical, Asahi Glass, and lately Solvay Solexis. Frequently, such membranes serve the dual function of reactant separation and selective ionic conduction between two otherwise separate compartments. For some applications, the compromise of the "separation" function via the degradation and mechanical failure of the electrolyte membrane can be the life-limiting factor; this is particularly the case for PEM in hydrogen/oxygen fuel cells.

  19. 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.

    2017-06-27

    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.

  20. 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.

  1. Surface chemistry and durability of borosilicate glass

    International Nuclear Information System (INIS)

    Carroll, S.A.; Bourcier, W.L.; Phillips, B.L.

    1994-01-01

    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. % Na 2 O, 5.97 wt. % CaO, 11.68 wt. % Al 2 O 3 , 8.43 wt. % B 2 O 3 , and 55.73 wt. % SiO 2 ) 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 + ] adsorbed 2 and [OH - ] adsorbed 0.8 , 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 - ] adsorbed 0.9 adsorbed . 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

  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. Effect of Soorh Metakaolin on Concrete Compressive Strength and Durability

    Directory of Open Access Journals (Sweden)

    A. Saand

    2017-12-01

    Full Text Available Concrete durability is a key aspect for forecasting the expected life time of concrete structures. In this paper, the effect of compressive strength and durability of concrete containing metakaolin developed from a local natural material (Soorh of Thatta Distict of Sindh, Pakistan is investigated. Soorh is calcined by an electric furnace at 8000C for 2 hours to produce metakaolin. One mix of ordinary concrete and five mixes of metakaolin concrete were prepared, where cement is replaced by developed metakaolin from 5% to 25% by weight, with 5% increment step. The concrete durability was tested for water penetration, carbonation depth and corrosion resistance. The obtained outcomes demonstrated that, 15% replacement level of local developed metakaolin presents considerable improvements in concrete properties. Moreover, a considerable linear relationship was established between compressive strength and concrete durability indicators like water penetration, carbonation depth and corrosion resistance.

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

    International Nuclear Information System (INIS)

    Jantzen, C.M.; Plodinec, M.J.

    1983-01-01

    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 (10 6 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. Development of a CB Resistant Durable, Flexible Hydration System

    National Research Council Canada - National Science Library

    Hall, Peyton W; Zeller, Frank T; Bulluck, John W; Dingus, Michael L

    2002-01-01

    A durable, flexible hydration system resistant to contamination by contact with VX, GD, and HD chemical agents, as well as damage by the decontaminants sodium hypochlorite and DS-2 is being developed for aviator use...

  6. Nanocomposites for Improved Physical Durability of Porous PVDF Membranes

    Science.gov (United States)

    Lai, Chi Yan; Groth, Andrew; Gray, Stephen; Duke, Mikel

    2014-01-01

    Current commercial polymer membranes have shown high performance and durability in water treatment, converting poor quality waters to higher quality suitable for drinking, agriculture and recycling. However, to extend the treatment into more challenging water sources containing abrasive particles, micro and ultrafiltration membranes with enhanced physical durability are highly desirable. This review summarises the current limits of the existing polymeric membranes to treat harsh water sources, followed by the development of nanocomposite poly(vinylidene fluoride) (PVDF) membranes for improved physical durability. Various types of nanofillers including nanoparticles, carbon nanotubes (CNT) and nanoclays were evaluated for their effect on flux, fouling resistance, mechanical strength and abrasion resistance on PVDF membranes. The mechanisms of abrasive wear and how the more durable materials provide resistance was also explored. PMID:24957121

  7. Durability studies on the high calcium flyash based GPC

    African Journals Online (AJOL)

    Keywords: Geopolymer concrete, high calcium flyash, durability, corrosion resistance, polarisation test. ... Reddy, et al (2011) reported that excellent resistance to chloride .... being the metal on the higher electro potential range, to the negative ...

  8. Durability of Bricks Coated with Red mud Based Geopolymer Paste

    Science.gov (United States)

    Singh, Smita; Basavanagowda, S. N.; Aswath, M. U.; Ranganath, R. V.

    2016-09-01

    The present study is undertaken to assess the durability of concrete blocks coated with red mud - fly ash based geopolymer paste. Concrete blocks of size 200 x 200 x 100mm were coated with geopolymer paste synthesized by varying the percentages of red mud and fly ash. Uncoated concrete blocks were also tested for the durability for comparison. In thermal resistance test, the blocks were subjected to 600°C for an hour whereas in acid resistance test, they were kept in 5% sulphuric acid solution for 4 weeks. The specimens were thereafter studied for surface degradation, strength loss and weight loss. Pastes with red mud percentage greater than 50% developed lot of shrinkage cracks. The blocks coated with 30% and 50% red mud paste showed better durability than the other blocks. The use of blocks coated with red mud - fly ash geopolymer paste improves the aesthetics, eliminates the use of plaster and improves the durability of the structure.

  9. The Overjustification Effect in Retarded Children: Durability and Generalizability.

    Science.gov (United States)

    Ogilvie, Lee; Prior, Margot

    1982-01-01

    Generalizability and durability of the overjustification effect (on decline in intrinsic motivation due to the lack of rewards in behavior modification programs) were examined in 35 normal preschool children and 17 mental age-matched retarded children. (Author/SW)

  10. Durability of filament-wound composite flywheel rotors

    Science.gov (United States)

    Koyanagi, Jun

    2012-02-01

    This paper predicts the durability of two types of flywheels, one assumes to fail in the radial direction and the other assumes to fail in the circumferential direction. The flywheel failing in the radial direction is a conventional filament-wound composite flywheel and the one failing in the circumferential direction is a tailor-made type. The durability of the former is predicted by Micromechanics of Failure (MMF) (Ha et al. in J. Compos. Mater. 42:1873-1875, 2008), employing time-dependent matrix strength, and that of the latter is predicted by Simultaneous Fiber Failure (SFF) (Koyanagi et al. in J. Compos. Mater. 43:1901-1914, 2009), employing identical time-dependent matrix strength. The predicted durability of the latter is much greater than that of the former, depending on the interface strength. This study suggests that a relatively weak interface is necessary for high-durability composite flywheel fabrication.

  11. Research notes : durability of composite repairs on bridges.

    Science.gov (United States)

    2009-08-01

    The research showed that conditions that allow moisture to get under the carbon fiber reinforced polymer composites (CFRP) combined with freeze-thaw were detrimental to durability. In addition, the results showed that the American Concrete Institute ...

  12. 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...

  13. 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

  14. Erectile Function Durability Following Permanent Prostate Brachytherapy

    International Nuclear Information System (INIS)

    Taira, Al V.; Merrick, Gregory S.; Galbreath, Robert W.; Butler, Wayne M.; Wallner, Kent E.; Kurko, Brian S.; Anderson, Richard; Lief, Jonathan H.

    2009-01-01

    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.

  15. Bonding Durability of Four Adhesive Systems

    Directory of Open Access Journals (Sweden)

    Leila Atash Biz Yeganeh

    2016-04-01

    Full Text Available Objectives: This study aimed to compare the durability of four adhesive systems by assessing their microtensile bond strength (MTBS and microleakage during six months of water storage.Materials and Methods: A total of 128 human third molars were used. The adhesives tested were Scotch Bond Multipurpose (SBMP, Single Bond (SB, Clearfil-SE bond (CSEB, and All-Bond SE (ABSE. After sample preparation for MTBS testing, the microspecimens were subjected to microtensile tester after one day and six months of water storage. For microleakage evaluation, facial and lingual class V cavities were prepared and restored with composite. After thermocycling, microleakage was evaluated. Bond strength values were subjected to one-way ANOVA and Tamhane’s test, and the microleakage data were analyzed by the Kruskal-Wallis, Dunn, Mann Whitney and Wilcoxon tests (P<0.05.Results: Single Bond yielded the highest and ABSE yielded the lowest bond strength at one day and six months. Short-term bond strength of SBMP and CSEB was similar. After six months, a significant decrease in bond strength was observed in ABSE and SBMP groups. At one day, ABSE showed the highest microleakage at the occlusal margin; however, at the gingival margin, there was no significant difference among groups. Long-term microleakage of all groups at the occlusal margins was similar, whilst gingival margins of SBMP and SB showed significantly higher microleakage.Conclusion: The highest MTBS and favorable sealability were obtained by Clearfil SE bond. Water storage had no effect on microleakage of self-etch adhesives at the gingival margin or MTBS of CSEB and SB. 

  16. Assessment of cement durability in repository environment

    International Nuclear Information System (INIS)

    Ferreira, E.G.A.; Vicente, R.; Isiko, V.L.K.; Miyamoto, H.; Marumo, J.T.; Gobbo, L.A.

    2015-01-01

    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. Manufacturing of Low Cost, Durable Membrane Electrode Assemblies Engineered for Rapid Conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Busby, Colin [W. L. Gore & Associates Inc., Newark, DE (United States)

    2017-05-23

    Over the past 20 years significant progress in membrane-electrode assembly (MEA) technology development for polymer electrolyte fuel cells (PEMFCs) has resulted in the PEMFC technology approaching a commercial reality for transportation applications. However, there remain two primary technical challenges to be addressed in the MEA. First and foremost is meeting the automotive cost targets: Producing a fuel cell stack cost competitive with today’s internal combustion engine. In addition to the material cost, MEA (and other components) and stack assembly production methods must be amenable for use in low cost, high speed, automotive assembly line. One impediment to this latter goal is that stack components must currently go through a long and tedious conditioning procedure before they produce optimal power. This so-called “break-in” can take many hours, and can involve quite complex voltage, temperature and/or pressure steps. These break-in procedures must be simplified and the time required reduced if fuel cells are to become a viable automotive engine. The second challenge is to achieve the durability targets in real-world automotive duty cycle operations. Significant improvements in cost, break-in time, and durability for the key component of fuel cell stacks, MEAs were achieved in this project. Advanced modeling was used to guide design of the new MEA to maximize performance and durability. A new, innovative process and manufacturing approach utilizing direct in-line coating using scalable, cost-competitive, continuous high volume 3-layer rolled-good manufacturing processes was developed and validated by single cell and short stack testing. In addition, the direct coating methods employed were shown to reduce the cost for sacrificial films. Furthermore, Gore has demonstrated a 10 µm reinforced membrane that is used in the new low-cost process and can meet automotive power density and durability targets. Across a wide range of operating conditions, the

  18. Durability, mechanical, and thermal properties of experimental glass-ceramic forms for immobilizing ICPP high level waste

    International Nuclear Information System (INIS)

    Vinjamuri, K.

    1990-01-01

    The high-level liquid waste generated at the Idaho Chemical Processing Plant (ICPP) is routinely solidified into granular calcined high-level waste (HLW) and stored onsite. Research is being conducted at the ICPP on methods of immobilizing the HLW, including developing a durable glass-ceramic form which has the potential to significantly reduce the final waste volume by up to 60% compared to a glass form. Simulated, pilot plant, non-radioactive, calcines similar to the composition of the calcined HLW and glass forming additives are used to produce experimental glass-ceramic forms. The objective of the research reported in this paper is to study the impact of ground calcine particle size on durability and mechanical and thermal properties of experimental glass-ceramic forms

  19. A structural bond strength model for glass durability

    International Nuclear Information System (INIS)

    Feng, Xiangdong; Metzger, T.B.

    1996-01-01

    A glass durability model, structural bond strength (SBS) model was developed to correlate glass durability with its composition. This model assumes that the strengths of the bonds between cations and oxygens and the structural roles of the individual elements in the glass arc 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 upon glass composition and the redox state of oxides. Al 2 O 3 , ZrO 2 , Fe 2 O 3 , and B 2 O 3 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 SiO 2 from alkalis. The percolation phenomenon in glass is also taken into account. The SBS model is applied to correlate the 7-day product consistency test durability of 42 low-level waste glasses with their composition with an R 2 of 0.87, which is better than 0.81 obtained with an eight-coefficient empirical first-order mixture model on the same data set

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

    International Nuclear Information System (INIS)

    Jantzen, C

    2006-01-01

    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

  1. Experimental Study on Color Durability of Color Asphalt Pavement

    Science.gov (United States)

    Ning, Shi; Huan, Su

    2017-06-01

    Aiming at the poor Color durability and the lack of research on Color asphalt pavement, spraying an anti-tire trace seal resin emulsion on the surface, a Color durable asphalt pavement was proposed. After long-term rolling and long-term aging test, the Color durability was evaluated by RGB function in Photoshop and trace residue rate formula. Test results proved that the Evaluation method was simple and effective. After long-term rolling, the Color of the road surface tends to a constant value. Spraying the emulsion on the road surface can resist tire traces. After long-term aging test, the resistance to tire traces was increased by 26.6% compared with the conventional type, while the former was 44.1% higher than the latter without long-term aging. The Color durable asphalt pavement can effectively improve the ability of Color asphalt pavement to resist tire traces, and significantly improve the Color durability of Color asphalt pavement.

  2. Bases for extrapolating materials durability in fuel storage pools

    International Nuclear Information System (INIS)

    Johnson, A.B. Jr.

    1994-12-01

    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

  3. Effect of manufactured sand on the durability characteristics of concrete

    Directory of Open Access Journals (Sweden)

    S. S. SARAVANAN

    2016-12-01

    Full Text Available Concrete is the most sought after material due to increase in construction activities and infrastructural developments. Availability of natural sand is decreasing thereby increase in the cost of construction. In the present work undertaken, an attempt has been made to give an alternative to natural sand. Optimization of replacement of natural sand with manufactured sand in concrete, durability studies such as water absorption, rapid chloride permeability test, sorptivity, acid resistance, alkaline resistance, impact resistance and abrasion resistance of M40 and M50 grades of concrete have been studied with manufactured sand as fine aggregate and compared the results with the conventional sand concrete. The results shows that there is an increase in the durability properties up to 70 % level of replacements of sand with manufactured sand as fine aggregate and for 100 % use of manufactured sand also gives the better durability than the conventional sand concrete.

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

    International Nuclear Information System (INIS)

    Parrott, L.J.; Lawrence, C.D.

    1992-01-01

    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)

  5. Durability reliability analysis for corroding concrete structures under uncertainty

    Science.gov (United States)

    Zhang, Hao

    2018-02-01

    This paper presents a durability reliability analysis of reinforced concrete structures subject to the action of marine chloride. The focus is to provide insight into the role of epistemic uncertainties on durability reliability. The corrosion model involves a number of variables whose probabilistic characteristics cannot be fully determined due to the limited availability of supporting data. All sources of uncertainty, both aleatory and epistemic, should be included in the reliability analysis. Two methods are available to formulate the epistemic uncertainty: the imprecise probability-based method and the purely probabilistic method in which the epistemic uncertainties are modeled as random variables. The paper illustrates how the epistemic uncertainties are modeled and propagated in the two methods, and shows how epistemic uncertainties govern the durability reliability.

  6. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Jha, M.C.; Berggren, M.H.

    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.

  7. Durability evaluation method on rebar corrosion of reinforced concrete

    International Nuclear Information System (INIS)

    Kitsutaka, Yoshinori

    2013-01-01

    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)

  8. Highly durable and low permeable concrete for LLW facilities

    International Nuclear Information System (INIS)

    Yanagibashi, Kunio; Saito, Toshio; Odagawa, Masaro.

    1997-01-01

    Concrete used for LLW facilities is required to be highly durable. The authors evaluated concrete containing glycol ether derivatives and silica fume as admixtures. Compressive strength, diffusion coefficient of water, depth of accelerated carbonation, drying shrinkage, depth of chlorides penetration and resistance to freezing and thawing were investigated using concrete specimens. Compressive strength, depth of accelerated carbonation, diffusion coefficient of 137 Cs were investigated using mortar specimens before and after irradiation of gamma rays. Results showed that using glycol ether derivatives and silica fume was effective in improving the durability. (author)

  9. Glycogen with short average chain length enhances bacterial durability

    Science.gov (United States)

    Wang, Liang; Wise, Michael J.

    2011-09-01

    Glycogen is conventionally viewed as an energy reserve that can be rapidly mobilized for ATP production in higher organisms. However, several studies have noted that glycogen with short average chain length in some bacteria is degraded very slowly. In addition, slow utilization of glycogen is correlated with bacterial viability, that is, the slower the glycogen breakdown rate, the longer the bacterial survival time in the external environment under starvation conditions. We call that a durable energy storage mechanism (DESM). In this review, evidence from microbiology, biochemistry, and molecular biology will be assembled to support the hypothesis of glycogen as a durable energy storage compound. One method for testing the DESM hypothesis is proposed.

  10. Physical properties and chemical durability of selected zirconia containing silicate glasses

    Directory of Open Access Journals (Sweden)

    ELEONÓRA GAŠPÁREKOVÁ

    2011-12-01

    Full Text Available Density, thermal expansion, glass transition temperature, refractive index, molar refractivity and chemical durability of five- and six-component glasses with as weighted composition xNa2O·(15-xK2O·yCaO∙(10-yZnO∙zZrO2∙(75-zSiO2 (x = 0, 7.5, 15; y = 0, 5, 10; z = 5, 7 were measured. The obtained experimental data were merged together with the previous results obtained for analogous glasses with lower zirconia content. The full set of glasses enabled the quantitative statistical estimation of possible mixed-oxide effects. The results of the multilinear regression analysis pointed out the ideal behavior of molar volume and molar refractivity. The strongest influence of mutual oxide interactions was found for chemical durability and glass transition temperature. The regression analysis of compositional dependence of metastable melt thermal expansion coefficient practically failed. The need of property-composition study based on the thermodynamic model was pointed out. Qualitatively the obtained results confirmed those previously obtained for the analogous glasses with zirconia content reaching up to 3 mol. %.

  11. 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

  12. Effect of Acidic Water on Strength, Durability and Corrosion of ...

    African Journals Online (AJOL)

    In this study, specimens of 108 cubes (150 mm x 150 mm x 150 mm), 36 cylinders (300 mm x 150 mm), and 72 cylinders (102 mm x 51 mm) were cast and cured in percentages of NaCl added water to find the workability, strength, durability and corrosion resistance characteristics concrete. The effect of corrosion of steel in ...

  13. Durability studies on the high calcium flyash based GPC ...

    African Journals Online (AJOL)

    Three different grades namely GM20, GM30 and GM40 are designed and common durability related properties like water absorption, acid resitance and corrosion resistance by constant voltage polarization test are determined using relevant concrete specimens and compared with similar grades of conventional concrete.

  14. Durable chemical sensors based on field-effect transistors

    NARCIS (Netherlands)

    Reinhoudt, David

    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

  15. Enhancing durability of wood-based composites with nanotechnology

    Science.gov (United States)

    Carol Clausen

    2012-01-01

    Wood protection systems are needed for engineered composite products that are susceptible to moisture and biodeterioration. Protection systems using nano-materials are being developed to enhance the durability of wood-based composites through improved resistance to biodeterioration, reduced environmental impact from chemical leaching, and improved resistance to...

  16. 40 CFR 86.1822-01 - Durability data vehicle selection.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Durability data vehicle selection. 86... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light...

  17. Application of Kingview and PLC in friction durability test system

    Science.gov (United States)

    Gao, Yinhan; Cui, Jing; Yang, Kaiyu; Ke, Hui; Song, Bing

    2013-01-01

    Using PLC and Kingview software, a friction durability test system is designed. The overall program, hardware configuration, software structure and monitoring interface are described in detail. PLC ensures the stability of data acquisition, and the KingView software makes the HMI easy to manipulate. The practical application shows that the proposed system is cheap, economical and highly reliable.

  18. Comparative durability of timber bridges in the USA

    Science.gov (United States)

    James P. Wacker; Brian K. Brashaw

    2017-01-01

    As engineers begin to utilize life-cycle-cost design approaches for timber bridges, there is a necessity for more reliable data about their durability and expected service life. This paper summarizes a comprehensive effort to assess the current condition of more than one hundred timber highway bridge superstructures throughout the United States. This national study was...

  19. 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

  20. Durability of adhesive glass-metal connections for structural applications

    NARCIS (Netherlands)

    Van Lancker, B.; Dispersyn, J.; De Corte, W.; Belis, J.

    2016-01-01

    The use of adhesive bonds for structural glass-metal connections in the building envelope has increased in recent years. Despite the multiple advantages compared to more traditional bolted connections, long-term behaviour and durability of the adhesives have to be investigated accurately. Because,

  1. Review: Durability and degradation issues of PEM fuel cell components

    NARCIS (Netherlands)

    Bruijn, de F.A.; Dam, V.A.T.; Janssen, G.J.M.

    2008-01-01

    Besides cost reduction, durability is the most important issue to be solved before commercialisation of PEM Fuel Cells can be successful. For a fuel cell operating under constant load conditions, at a relative humidity close to 100% and at a temperature of maximum 75 °C, using optimal stack and flow

  2. 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.

  3. The durability and mechanical strenght properties of bamboo in ...

    African Journals Online (AJOL)

    The durability and mechanical strenght properties of bamboo in reinforced concrete. GA Alade, FA Olutoge, AA Alade. Abstract. No Abstract. Journal of Applied Science, Engineering and Technology Vol. 4(2) 2004: 35-40. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  4. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. 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 condition...

  6. Framework for a procedure for design for durability

    NARCIS (Netherlands)

    Siemes, A.J.M.

    1996-01-01

    The design for durability of structures and building components is in general based on implicit requirements with respect to the quality and dimensions of the composing building materials and components. These requirements are based on long term experience. This approach has disadvantages. It is

  7. Développement durable de l'agriculture urbaine

    International Development Research Centre (IDRC) Digital Library (Canada)

    La gestion concertée et durable des filières maraîchères urbaines, Paule Moustier, Michel ..... avec des eaux usées, le plus souvent non traitées : dans quelle mesure cette agriculture peut-elle ...... Le contrôle des performances zootechniques

  8. Ancient analogues concerning stability and durability of cementitious wasteform

    International Nuclear Information System (INIS)

    Jiang, W.; Roy, D.M.

    1994-01-01

    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

  9. 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 component...

  10. Structural analysis of highly-durable Si-O-C composite anode prepared by electrodeposition for lithium secondary batteries

    International Nuclear Information System (INIS)

    Nara, Hiroki; Yokoshima, Tokihiko; Otaki, Mitsutoshi; Momma, Toshiyuki; Osaka, Tetsuya

    2013-01-01

    The structure of the highly durable silicon-based anode prepared by electrodeposition was investigated for volume change and chemical structure. With repeated charge–discharge cycles, the volume change resulting from the anode film thickness decreased, and, after 100 cycles, essentially no difference was observed between the charged and discharged states. The buffering effect of the volume change was considered to be achieved by the formation of Li 2 O, Li 2 CO 3 , and lithium silicates such as Li 4 SiO 4 , whose existence were supported by STEM, EELS, and XPS analyses. From the structural analyses, the main reactions related to the capacity of the silicon-based anode were considered to be the formation of Li x Si and Li 2 Si 2 O 5 . Li x Si and Li 2 Si 2 O 5 can be delithiated into Si and SiO 2 , respectively

  11. Durability-Based Design Criteria for a Quasi-Isotropic Carbon-Fiber-Reinforced Thermoplastic Automotive Composite

    Energy Technology Data Exchange (ETDEWEB)

    Naus, Dan J [ORNL; Corum, James [ORNL; Klett, Lynn B [ORNL; Davenport, Mike [ORNL; Battiste, Rick [ORNL; Simpson, Jr., William A [ORNL

    2006-04-01

    This report provides recommended durability-based design properties and criteria for a quais-isotropic carbon-fiber thermoplastic composite for possible automotive structural applications. The composite consisted of a PolyPhenylene Sulfide (PPS) thermoplastic matrix (Fortron's PPS - Ticona 0214B1 powder) reinforced with 16 plies of carbon-fiber unidirectional tape, [0?/90?/+45?/-45?]2S. The carbon fiber was Hexcel AS-4C and was present in a fiber volume of 53% (60%, by weight). The overall goal of the project, which is sponsored by the U.S. Department of Energy's Office of Freedom Car and Vehicle Technologies and is closely coordinated with the Advanced Composites Consortium, is to develop durability-driven design data and criteria to assure the long-term integrity of carbon-fiber-based composite systems for automotive structural applications. This document is in two parts. Part 1 provides design data and correlations, while Part 2 provides the underlying experimental data and models. The durability issues addressed include the effects of short-time, cyclic, and sustained loadings; temperature; fluid environments; and low-energy impacts (e.g., tool drops and kickups of roadway debris) on deformation, strength, and stiffness. Guidance for design analysis, time-independent and time-dependent allowable stresses, rules for cyclic loadings, and damage-tolerance design guidance are provided.

  12. Complexing agents and pH influence on chemical durability of type I moulded glass containers.

    Science.gov (United States)

    Biavati, Alberto; Poncini, Michele; Ferrarini, Arianna; Favaro, Nicola; Scarpa, Martina; Vallotto, Marta

    2017-06-16

    Among the factors that affect the glass surface chemical durability, pH and complexing agents presence in aqueous solution have the main role (1). Glass surface attack can be also related to the delamination issue with glass particles appearance in the pharmaceutical preparation. A few methods to check for glass containers delamination propensity and some control guidelines have been proposed (2,3). The present study emphasizes the possible synergy between a few complexing agents with pH on the borosilicate glass chemical durability. Hydrolytic attack was performed in small volume 23 ml type I glass containers autoclaved according to EP or USP for 1 hour at 121°C, in order to enhance the chemical attack due to time, temperature and the unfavourable surface/volume ratio. 0,048 M or 0.024 M (moles/liter) solutions of the acids citric, glutaric, acetic, EDTA (ethylenediaminetetraacetic acid) and sodium phosphate with water for comparison, were used for the trials. The pH was adjusted ± 0,05 units at fixed values 5,5-6,6-7-7,4-8-9 by LiOH diluted solution. Since silicon is the main glass network former, silicon release into the attack solutions was chosen as the main index of the glass surface attack and analysed by ICPAES. The work was completed by the analysis of the silicon release in the worst attack conditions, of moulded glass, soda lime type II and tubing borosilicate glass vials to compare different glass compositions and forming technologies. Surface analysis by SEM was finally performed to check for the surface status after the worst chemical attack condition by citric acid. Copyright © 2017, Parenteral Drug Association.

  13. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Berggren, M.H.; Jha, M.C.

    1989-10-01

    AMAX Research Development Center (AMAX R D) investigated methods for enhancing the reactivity and durability of zinc ferrite desulfurization sorbents. 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 this 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. Two base case sorbents, a spherical pellet and a cylindrical extrude used in related METC-sponsored projects, were used to provide a basis for the aimed enhancement in durability and reactivity. Sorbent performance was judged on the basis of physical properties, single particle kinetic studies based on thermogravimetric (TGA) techniques, and multicycle bench-scale testing of sorbents. A sorbent grading system was utilized to quantify the characteristics of the new sorbents prepared during the program. Significant enhancements in both reactivity and durability were achieved for the spherical pellet shape over the base case formulation. Overall improvements to reactivity and durability were also made to the cylindrical extrude shape. The primary variables which were investigated during the program included iron oxide type, zinc oxide:iron oxide ratio, inorganic binder concentration, organic binder concentration, and induration conditions. The effects of some variables were small or inconclusive. Based on TGA studies and bench-scale tests, induration conditions were found to be very significant.

  14. Multi-factor Effects on the Durability of Recycle Aggregate Concrete

    Science.gov (United States)

    Ma, Huan; Cui, Yu-Li; Zhu, Wen-Yu; Xie, Xian-Jie

    2016-05-01

    Recycled Aggregate Concrete (RAC) was prepared with different recycled aggregate replacement ratio, 0, 30%, 70% and 100% respectively. The performances of RAC were examined by the freeze-thaw cycle, carbonization and sulfate attack to assess the durability. Results show that test sequence has different effects on the durability of RAC; the durability is poorer when carbonation experiment was carried out firstly, and then other experiment was carried out again; the durability is better when recycled aggregate replacement ratio is 70%.

  15. 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....

  16. 30 CFR 816.73 - Disposal of excess spoil: Durable rock fills.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Disposal of excess spoil: Durable rock fills...-SURFACE MINING ACTIVITIES § 816.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

  17. 30 CFR 817.73 - Disposal of excess spoil: Durable rock fills.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Disposal of excess spoil: Durable rock fills...-UNDERGROUND MINING ACTIVITIES § 817.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

  18. Design of concrete structures for durability. Example: Chloride penetration in the lining of a bored tunnel

    NARCIS (Netherlands)

    Siemes, A.J.M.

    1998-01-01

    The present design method for durability of concrete is based on a set of rules that give no objective in-sight in the service life to expect from the concrete structure. An objective comparison between different durability measures is therefor not possible. Especially if the lack of durability can

  19. 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

  20. Natural look in volume restoration.

    Science.gov (United States)

    Lupo, Mary P

    2008-09-01

    Filling and volumizing injection procedures are currently widely used for facial augmentation and re-establishing a youthful appearance. Aesthetic physicians have advanced from the practice of treating single lines and wrinkles towards filling large facial areas to globally restore natural facial contours and meet patient demand for nonsurgical rejuvenation. This review describes the different categories of fillers and volumizers based on their duration of action and ability to create a natural looking effect; they can be broadly classified as temporary or long-lasting biodegradable agents, or permanent nonbiodegradable agents. Temporary fillers are effective to correct lines and wrinkles, but may not adequately meet the need for global facial rejuvenation and volume replacement in a long-term, cost-efficient manner. Permanent fillers for global restoration pose the issue of long-term safety, and may not be compatible with changes in facial architecture with continued aging. Longer lasting volumizers provide patients with a durable, effective option for the restoration of facial volume and the re-establishment of youthful facial contours. Temporary fillers and volumizers may also be used in combination to provide a wide source of options for the global restoration and rejuvenation of the face.

  1. 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.

  2. 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.

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

    OpenAIRE

    Banerjee, Sumitro; Soberman, David A.

    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...

  4. Durability of fired clay bricks containing granite powder

    OpenAIRE

    Xavier, G. C.; Saboya, F.; Maia, P. C.; Alexandre, J.

    2012-01-01

    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 weather...

  5. Durable zinc ferrite sorbent pellets for hot coal gas desulfurization

    Science.gov (United States)

    Jha, Mahesh C.; Blandon, Antonio E.; Hepworth, Malcolm T.

    1988-01-01

    Durable, porous sulfur sorbents useful in removing hydrogen sulfide from hot coal gas are prepared by water pelletizing a mixture of fine zinc oxide and fine iron oxide with inorganic and organic binders and small amounts of activators such as sodium carbonate and molybdenite; the pellets are dried and then indurated at a high temperature, e.g., 1800.degree. C., for a time sufficient to produce crush-resistant pellets.

  6. Des effets durables : Asie | CRDI - Centre de recherches pour le ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    6 juin 2014 ... Le Projet hippocampe devient un important protagoniste de la conservation de la faune marine. En savoir plus. L'Initiative pour les micronutriments : des solutions durables à la faim inapparente · L'information améliore les conditions de vie dans les Philippines · De l'eau potable dans les foyers grâce à un ...

  7. Durability of light steel framing in residential applications

    OpenAIRE

    Lawson, RM; Popo-Ola, S.O.; Way, A.; Heatley, T; Pedreschi, Remo

    2010-01-01

    This paper presents a summary and analysis of research findings on the durability of galvanised cold-formed steel sections used in housing in order to deduce their design life. These cold-formed sections are produced from pre-galvanised strip steel. It reviews reports and publications from research projects carried out by Corus and the Steel Construction Institute on zinc-coated, cold-formed steel products. New data have also been gathered from measurements on houses and similar buildings tha...

  8. THE CONCEPT OF COMPETITIVE ADVANTAGES. LOGIC, SOURCES AND DURABILITY

    OpenAIRE

    Cegliński, Paweł

    2017-01-01

    Purpose: The main purpose of this article is to present theoretical assumptions of the concept of competitive advantages and main problems connected with the same. Most of all, the article outlines issues, which are presently discussed in the field of management sciences, including sources of competitive advantages, causal ambiguity and character of durability of competitive advantages in the contemporary turbulent business environment. In the author’s opinion, the issues have a great signifi...

  9. AGRICULTURE DURABLE De nouvelles pratiques sont source de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    17 nov. 2010 ... Depuis 1970, les travaux de recherche soutenus par le CRDI ont permis à des agriculteurs et à des collectivités de pays en développement d'adopter des pratiques agricoles durables. Le résultant? Une productivité accrue, un recul de la pauvreté, une plus grande sécurité alimentaire et un environnement ...

  10. Lightweight, Durable Army Antennas Using Carbon Nanotube Technology

    Science.gov (United States)

    2013-01-01

    may be adjusted by collecting the sheet on a revolving substrate conveyor belt (e.g., Teflon belt ), as shown in figure 15 (12). SEM images of the... designated by other authorized documents. Citation of manufacturer’s or trade names does not constitute an official endorsement or approval of the use...CNT) materials to produce lightweight, flexible, and durable alternatives to existing and future Army antenna designs is explored through fabrication

  11. Durable-Goods Monopolists, Network Effects and Penetration Pricing

    OpenAIRE

    Cyrus C.Y. Chu; Hung-Ken Chien

    2005-01-01

    We study the pricing problem of a durable-goods monopolist. With network effects, consumption externalities among heterogeneous groups of consumers generate a discontinuous demand function. Consequently, the lessor has to offer a low price in order to reach the mass market, whereas the seller has the option to build a customer base by setting a lower initial price and raise the price later in the mass market, which explains the practice of introductory pricing. Contrary to the existing litera...

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

    International Nuclear Information System (INIS)

    2001-01-01

    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.)

  13. The influence of adherent surface preparation on bond durability

    International Nuclear Information System (INIS)

    Rider, A.N.; Arnott, D.R.; Olsson-Jacques, C.L.

    1999-01-01

    Full text: One of the major factors limiting the use of adhesive bonding is the problem associated with the production of adhesive joints that can maintain their initial strength over long periods of time in hostile environments. It is well known that the adherent surface preparation method is critical to the formation of a durable adhesive bond. Work presented in this paper focuses on the critical aspects of the surface preparation of aluminium employed for the manufacture of aluminium-epoxy joints. The surface preparation procedure examined is currently employed by the RAAF for repairs requiring metal to adhesive bonding. The influence of each step in the surface preparation on the ultimate bond durability performance of the adhesive joint is examined by a combination of methods. Double cantilever wedge style adhesive joints are loaded in mode 1 opening and then exposed to a humid environment. X-ray photoelectron spectroscopy (XPS) and contact angle measurements of the aluminium adherent before bonding provides information about the adherent surface chemistry. XPS is also employed to analyse the surfaces of the bonded specimens post failure to establish the locus of fracture. This approach provides important information regarding the properties influencing bond durability as well as the bond failure mechanisms. A two step bond degradation model was developed to qualitatively describe the observed bond durability performance and fracture data. The first step involves controlled moisture ingress by stress induced microporosity of the adhesive in the interfacial region. The second step determines the locus of fracture through the relative dominance of one of three competitive processes, viz: oxide degradation, polymer desorption, or polymer degradation. A key element of the model is the control exercised over the interfacial microporosity by the combined interaction of stress and the relative densities of strong and weak linkages at the metal to adhesive interface

  14. Standard test methods for determining chemical durability of nuclear, hazardous, and mixed waste glasses and multiphase glass ceramics: The product consistency test (PCT)

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 These product consistency test methods A and B evaluate the chemical durability of homogeneous glasses, phase separated glasses, devitrified glasses, glass ceramics, and/or multiphase glass ceramic waste forms hereafter collectively referred to as “glass waste forms” by measuring the concentrations of the chemical species released to a test solution. 1.1.1 Test Method A is a seven-day chemical durability test performed at 90 ± 2°C in a leachant of ASTM-Type I water. The test method is static and conducted in stainless steel vessels. Test Method A can specifically be used to evaluate whether the chemical durability and elemental release characteristics of nuclear, hazardous, and mixed glass waste forms have been consistently controlled during production. This test method is applicable to radioactive and simulated glass waste forms as defined above. 1.1.2 Test Method B is a durability test that allows testing at various test durations, test temperatures, mesh size, mass of sample, leachant volume, a...

  15. 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.

  16. 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.

  17. 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.

  18. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. 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.

  20. Durable transparent carbon nanotube films for flexible device components

    International Nuclear Information System (INIS)

    Sierros, K.A.; Hecht, D.S.; Banerjee, D.A.; Morris, N.J.; Hu, L.; Irvin, G.C.; Lee, R.S.; Cairns, D.R.

    2010-01-01

    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.

  1. Preliminary results of durability testing with borosilicate glass compositions

    International Nuclear Information System (INIS)

    Adel-Hadadi, M.; Adiga, R.; Barkatt, Aa.

    1987-01-01

    This is a report on the first year of research conducted at the Vitreous State Laboratory of the Catholic University of America in support of the West Valley Demonstration Project. One objective is the vitrification of liquid waste generated by previous nuclear fuel reprocessing. This work has been directed principally at the problem of glass composition optimization. This has necessitated the development of a coordinated program of glass production, durability measurements, and processability assessment. A small-scale continuous melter has been constructed for melting uranium and thorium containing glasses and for studying glass processing characteristics. Glass viscosities have been measured over a range of temperatures. A large number of glasses have also been produced in small crucible melts. Glass durability has been assessed using four types of leach tests: MCC-3, MCC-1, IAEA/ISO, and pulsed-flow tests. Extensive data from these tests are reported. The data have led to the design of very durable glasses (comparable to the Savannah River Laboratory Defense Waste Reference Glass) which have the requisite waste loading and processing characteristics. 14 refs., 4 figs., 77 tabs

  2. Reliability algorithms applied to reinforced concrete structures durability assessment

    Directory of Open Access Journals (Sweden)

    C. G. Nogueira

    Full Text Available This paper addresses the analysis of probabilistic corrosion time initiation in reinforced concrete structures exposed to ions chloride penetration. Structural durability is an important criterion which must be evaluated in every type of structure, especially when these structures are constructed in aggressive atmospheres. Considering reinforced concrete members, chloride diffusion process is widely used to evaluate the durability. Therefore, at modelling this phenomenon, corrosion of reinforcements can be better estimated and prevented. These processes begin when a threshold level of chlorides concentration is reached at the steel bars of reinforcements. Despite the robustness of several models proposed in the literature, deterministic approaches fail to predict accurately the corrosion time initiation due to the inherently randomness observed in this process. In this regard, the durability can be more realistically represented using probabilistic approaches. A probabilistic analysis of ions chloride penetration is presented in this paper. The ions chloride penetration is simulated using the Fick's second law of diffusion. This law represents the chloride diffusion process, considering time dependent effects. The probability of failure is calculated using Monte Carlo simulation and the First Order Reliability Method (FORM with a direct coupling approach. Some examples are considered in order to study these phenomena and a simplified method is proposed to determine optimal values for concrete cover.

  3. Complexing Agents and pH Influence on Chemical Durability of Type I Molded Glass Containers.

    Science.gov (United States)

    Biavati, Alberto; Poncini, Michele; Ferrarini, Arianna; Favaro, Nicola; Scarpa, Martina; Vallotto, Marta

    2017-01-01

    Among the factors that affect the glass surface chemical durability, pH and complexing agents present in aqueous solution have the main role. Glass surface attack can be also related to the delamination issue causing glass particles' appearance in the pharmaceutical preparation. A few methods to check for glass containers delamination propensity and some control guidelines have been proposed. The present study emphasizes the possible synergy between a few complexing agents with pH on borosilicate glass chemical durability.Hydrolytic attack was performed in small-volume 23 mL type I glass containers autoclaved according to the European Pharmacopoeia or United States Pharmacopeia for 1 h at 121 °C, in order to enhance the chemical attack due to time, temperature, and the unfavorable surface/volume ratio. Solutions of 0.048 M or 0.024 M (M/L) of the acids citric, glutaric, acetic, EDTA (ethylenediaminetetraacetic acid), together with sodium phosphate with water for comparison, were used for the trials. The pH was adjusted ±0.05 units at fixed values 5.5, 6.6, 7, 7.4, 8, and 9 by LiOH diluted solution.Because silicon is the main glass network former, silicon release into the attack solutions was chosen as the main index of the glass surface attack and analysed by inductively coupled plasma atomic emission spectrophotometry. The work was completed by the analysis of the silicon release in the worst attack conditions of molded glass, soda lime type II glass, and tubing borosilicate glass vials to compare different glass compositions and forming technologies. Surface analysis by scanning electron microscopy was finally performed to check for the surface status after the worst chemical attack condition by citric acid. LAY ABSTRACT: Glass, like every packaging material, can have some usage limits, mainly in basic pH solutions. The issue of glass surface degradation particles that appear in vials (delamination) has forced a number of drug product recalls in recent years

  4. 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.)

  5. Enhancing the Durability and Carrier Selectivity of Perovskite Solar Cells Using a Blend Interlayer.

    Science.gov (United States)

    Sin, Dong Hun; Jo, Sae Byeok; Lee, Seung Goo; Ko, Hyomin; Kim, Min; Lee, Hansol; Cho, Kilwon

    2017-05-31

    A mechanically and thermally stable and electron-selective ZnO/CH 3 NH 3 PbI 3 interface is created via hybridization of a polar insulating polymer, poly(ethylene glycol) (PEG), into ZnO nanoparticles (NPs). PEG successfully passivates the oxygen defects on ZnO and prevents direct contact between CH 3 NH 3 PbI 3 and defects on ZnO. A uniform CH 3 NH 3 PbI 3 film is formed on a soft ZnO:PEG layer after dispersion of the residual stress from the volume expansion during CH 3 NH 3 PbI 3 conversion. PEG also increases the work of adhesion of the CH 3 NH 3 PbI 3 film on the ZnO:PEG layer and holds the CH 3 NH 3 PbI 3 film with hydrogen bonding. Furthermore, PEG tailors the interfacial electronic structure of ZnO, reducing the electron affinity of ZnO. As a result, a selective electron-collection cathode is formed with a reduced electron affinity and a deep-lying valence band of ZnO, which significantly enhances the carrier lifetime (473 μs) and photovoltaic performance (15.5%). The mechanically and electrically durable ZnO:PEG/CH 3 NH 3 PbI 3 interface maintains the sustainable performance of the solar cells over 1 year. A soft and durable cathodic interface via PEG hybridization in a ZnO layer is an effective strategy toward flexible electronics and commercialization of the perovskite solar cells.

  6. Utilizing waste materials to enhance mechanical and durability characteristics of concrete incorporated with silica fume

    Directory of Open Access Journals (Sweden)

    Hamza Ali

    2017-01-01

    Full Text Available Construction and demolition wastes are increasing significantly due to augmented boom of modern construction. Although the partial cement replacement materials do promote the idea of sustainable construction, the use of construction and demolition waste can also be considered to be viable option to advance the sustainability in modern construction practices. This paper investigates the use of industrial waste materials namely marble dust and crushed bricks as replacement of natural fine aggregates along with the use of silica fume as a partial cement replacement on the mechanical properties and durability characteristics of concrete. Partial replacement levels of waste materials were 10 and 20 percent by volume while the partial replacement level of silica fume was kept to 20 percent at all concrete samples. The results reported in this paper show that the use of marble dust as a replacement material to the natural fine aggregates resulted in an increase in the mechanical properties of concrete. However, the use of crushed bricks did not substantially contribute in the development of strength. Water permeability of concrete incorporated with both silica fume and waste materials (marble dust and crushed bricks decreased significantly. The decrease in water permeability of concrete was attributed to the pozzolanic reaction of silica fume with calcium hydroxide of cement and the filler effect of the waste materials of marble dust and crushed bricks. The use of waste materials also enhance the freeze and thaw resistance of concrete. Authors strongly suggest that the pozzolanic reaction and the development of the microstructure of the concrete through the use of waste materials are largely responsible from the advances in the durability of concrete.

  7. Evaluation on the long-term durability and leachability of cemented waste form

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Hong; Lee, Jae Won; Ryue, Young Gerl [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-08-01

    The long-term durability and leachability on the cemented waste form containing boric acids produced in domestic nuclear nuclear power plants were evaluated. Compressive strength of waste form after durability test such as thermal stability and water immersion cycle was higher than before test and consistently increased with increasing of test time in range of 83 of 286 kgf/cm{sup 2}. Long-term leachability was evaluated by standard test methods, leach affecting factors, and prediction of long-term leachability with result data of short-term leach test. In all leach tests, the release of Cs-137 was controlled by diffusion, whereas release of Co-60 was not controlled by diffusion. Leach rate of Cs-137 was relatively constant at standard leach test methods such as NAS 16.1, IAEA, ISO-6961, and MCC-1, but that of Co-60 increased with leachant-renewal frequencies. The leach rate of both Cs-137 and Co-60 increased as test temperature raised. The release of Co-137 decreased in simulated seawater as leachant, but increased with increasing leachant volume. The prediciton of long-term release of Cs-137 from large-scale waste form using the results from short-term leach test of small-scale waste form were within {+-} 5% of actual release. The leachability indexes of Cs-137 were between 6.5 and 7.5 and those of Co-60 were ranged from 11.6 to 13.3, increasing as cumulative leaching time increased. (author). 22 refs., 14 figs., 15 tabs.

  8. Predictive Nomogram for the Durability of Pain Relief From Gamma Knife Radiation Surgery in the Treatment of Trigeminal Neuralgia

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, John T., E-mail: johnthomas75@gmail.com [Department of Radiation Oncology, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina (United States); Nida, Adrian M. [Biomedical Informatics Center, Medical University of South Carolina, Charleston, South Carolina (United States); Isom, Scott [Department of Biostatistical Sciences, Section of Biostatistics, Wake Forest School of Medicine, Winston-Salem, North Carolina (United States); Marshall, Kopriva [Wake Forest School of Medicine, Winston-Salem, North Carolina (United States); Bourland, John D. [Department of Radiation Oncology, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina (United States); Laxton, Adrian W.; Tatter, Stephen B. [Department of Neurosurgery, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina (United States); Chan, Michael D. [Department of Radiation Oncology, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina (United States)

    2014-05-01

    Purpose: To determine factors associated with the durability of stereotactic radiation surgery (SRS) for treatment of trigeminal neuralgia (TN). Methods and Materials: Between 1999 and 2008, 446 of 777 patients with TN underwent SRS and had evaluable follow-up in our electronic medical records and phone interview records. The median follow-up was 21.2 months. The Barrow Neurologic Institute (BNI) pain scale was used to determine pre- and post-SRS pain. Dose-volume anatomical measurements, Burchiel pain subtype, pain quality, prior procedures, and medication usage were included in this retrospective cohort to identify factors impacting the time to BNI 4-5 pain relapse by using Cox proportional hazard regression. An internet-based nomogram was constructed based on predictive factors of durable relief pre- and posttreatment at 6-month intervals. Results: Rates of freedom from BNI 4-5 failure at 1, 3, and 5 years were 84.5%, 70.4%, and 46.9%, respectively. Pain relief was BNI 1-3 at 1, 3, and 5 years in 86.1%, 74.3%, and 51.3% of type 1 patients; 79.3%, 46.2%, and 29.3% of type 2 patients; and 62.7%, 50.2%, and 25% of atypical facial pain patients. BNI type 1 pain score was achieved at 1, 3, and 5 years in 62.9%, 43.5%, and 22.0% of patients with type 1 pain and in 47.5%, 25.2%, and 9.2% of type 2 patients, respectively. Only 13% of patients with atypical facial pain achieved BNI 1 response; 42% of patients developed post-Gamma Knife radiation surgery (GKRS) trigeminal dysfunction. Multivariate analysis revealed that post-SRS numbness (hazard ratio [HR], 0.47; P<.0001), type 1 (vs type 2) TN (HR, 0.6; P=.02), and improved post-SRS BNI score at 6 months (HR, 0.009; P<.0001) were predictive of a durable pain response. Conclusions: The durability of SRS for TN depends on the presenting Burchiel pain type, the post-SRS BNI score, and the presence of post-SRS facial numbness. The durability of pain relief can be estimated pre- and posttreatment by using our

  9. Predictive Nomogram for the Durability of Pain Relief From Gamma Knife Radiation Surgery in the Treatment of Trigeminal Neuralgia

    International Nuclear Information System (INIS)

    Lucas, John T.; Nida, Adrian M.; Isom, Scott; Marshall, Kopriva; Bourland, John D.; Laxton, Adrian W.; Tatter, Stephen B.; Chan, Michael D.

    2014-01-01

    Purpose: To determine factors associated with the durability of stereotactic radiation surgery (SRS) for treatment of trigeminal neuralgia (TN). Methods and Materials: Between 1999 and 2008, 446 of 777 patients with TN underwent SRS and had evaluable follow-up in our electronic medical records and phone interview records. The median follow-up was 21.2 months. The Barrow Neurologic Institute (BNI) pain scale was used to determine pre- and post-SRS pain. Dose-volume anatomical measurements, Burchiel pain subtype, pain quality, prior procedures, and medication usage were included in this retrospective cohort to identify factors impacting the time to BNI 4-5 pain relapse by using Cox proportional hazard regression. An internet-based nomogram was constructed based on predictive factors of durable relief pre- and posttreatment at 6-month intervals. Results: Rates of freedom from BNI 4-5 failure at 1, 3, and 5 years were 84.5%, 70.4%, and 46.9%, respectively. Pain relief was BNI 1-3 at 1, 3, and 5 years in 86.1%, 74.3%, and 51.3% of type 1 patients; 79.3%, 46.2%, and 29.3% of type 2 patients; and 62.7%, 50.2%, and 25% of atypical facial pain patients. BNI type 1 pain score was achieved at 1, 3, and 5 years in 62.9%, 43.5%, and 22.0% of patients with type 1 pain and in 47.5%, 25.2%, and 9.2% of type 2 patients, respectively. Only 13% of patients with atypical facial pain achieved BNI 1 response; 42% of patients developed post-Gamma Knife radiation surgery (GKRS) trigeminal dysfunction. Multivariate analysis revealed that post-SRS numbness (hazard ratio [HR], 0.47; P<.0001), type 1 (vs type 2) TN (HR, 0.6; P=.02), and improved post-SRS BNI score at 6 months (HR, 0.009; P<.0001) were predictive of a durable pain response. Conclusions: The durability of SRS for TN depends on the presenting Burchiel pain type, the post-SRS BNI score, and the presence of post-SRS facial numbness. The durability of pain relief can be estimated pre- and posttreatment by using our

  10. Problematique De L'amenagement Des Aires Protegees Au Togo ...

    African Journals Online (AJOL)

    Cette étude s'est basée essentiellement sur la collecte des données, les entretiens et sur les recherches documentaires. Les résultats des différentes investigations montrent que l'aménagement des aires protégées est empêché par un certain nombre de facteurs qui sont liés à un manque de financement, de personnes ...

  11. Durability of precast prestressed concrete piles in marine environment, part 2. Volume 1 : concrete.

    Science.gov (United States)

    2012-06-01

    The overall purpose of this research was to determine methods which may be applied : economically to mitigate corrosion of reinforcement in precast prestressed concrete piles in : Georgias marine environments. The research was divided into two par...

  12. 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

  13. Advanced Stirling Convertor Durability Testing: Plans and Interim Results

    Science.gov (United States)

    Meer, David W.; Oriti, Salvatore M.

    2012-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Corporation (LM), and NASA Glenn Research Center (GRC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. In support of this program, GRC has been involved in testing Stirling convertors, including the Advanced Stirling Convertor (ASC), for use in the ASRG. This testing includes electromagnetic interference/compatibility (EMI/EMC), structural dynamics, advanced materials, organics, and unattended extended operation. The purpose of the durability tests is to experimentally demonstrate the margins in the ASC design. Due to the high value of the hardware, previous ASC tests focused on establishing baseline performance of the convertors within the nominal operating conditions. The durability tests present the first planned extension of the operating conditions into regions beyond those intended to meet the product spec, where the possibility exists of lateral contact, overstroke, or over-temperature events. These tests are not intended to cause damage that would shorten the life of the convertors, so they can transition into extended operation at the conclusion of the tests. This paper describes the four tests included in the durability test sequence: 1) start/stop cycling, 2) exposure to constant acceleration in the lateral and axial directions, 3) random vibration at increased piston amplitude to induce contact events, and 4) overstroke testing to simulate potential failures during processing or during the mission life where contact events could occur. The paper also summarizes the analysis and simulation used to predict the results of each of these tests.

  14. 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.

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

    International Nuclear Information System (INIS)

    Kurashige, Isao; Imoto, Harutake; Yamamoto, Takeshi; Hironaga, Michihiko

    2006-01-01

    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)

  16. 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...

  17. Deformable and durable phantoms with controlled density of scatterers

    Energy Technology Data Exchange (ETDEWEB)

    Bisaillon, Charles-Etienne; Lamouche, Guy; Dufour, Marc; Monchalin, Jean-Pierre [Industrial Materials Institute, National Research Council Canada, 75 de Mortagne, Boucherville, Quebec J4B 6Y4 (Canada); Maciejko, Romain [Optoelectronics Laboratory, Engineering Physics, Ecole Polytechnique de Montreal, PO Box 6079, Station ' Centre-ville' Montreal, Quebec H3C 3A7 (Canada)], E-mail: charles-etienne.bisaillon@cnrc-nrc.gc.ca, E-mail: guy.lamouche@cnrc-nrc.gc.ca, E-mail: marc.dufour@cnrc-nrc.gc.ca, E-mail: jean-pierre.monchalin@cnrc-nrc.gc.ca, E-mail: romain.maciejko@polytml.ca

    2008-07-07

    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. (note)

  18. SEM investigation of incandescent lamp mantle structure on durability

    International Nuclear Information System (INIS)

    Gerneke, D.; Lang, C.

    2002-01-01

    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

  19. 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.

  20. Durable zinc oxide-containing sorbents for coal gas desulfurization

    Science.gov (United States)

    Siriwardane, Ranjani V.

    1996-01-01

    Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.

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

    Energy Technology Data Exchange (ETDEWEB)

    Engle, J. W.; Gagnon, K.; Severin, G. W.; Valdovinos, H. F.; Nickles, R. J.; Barnhart, T. E. [Chemistry Division - Isotopes, Inorganics and Actinides, Los Alamos National Laboratory, Los Alamos, NM (United States); Department of Radiation Oncology, University of Washington, Seattle, WA (United States); Hevesy Laboratory, Danish Technical University, Risoe (Denmark); Department of Medical Physics, University of Wisconsin, WI, Madison (United States)

    2012-12-19

    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 {mu}m 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 {mu}m (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 currents in excess of 80 {mu}A.

  2. Electrostimulated recovery of welded joint durability: experiment and model

    International Nuclear Information System (INIS)

    Semakin, E.V.; Chirakadze, D.Z.; Tsellermaer, V.Ya.; Gromov, V.E.; Sosnin, O.V.

    1997-01-01

    The possibility to increase the durability of welded joints operating under conditions of low cycle fatigue is shown to be brought about using electric current pulses. Experimental method of recovery of operational capability is demonstrated on welded joints of tool steels R6M5 and 40Kh/ The onset of critical stage of fatigue in the welded joint was determined by ultrasonic testing. Then the specimens were treated with 20 Hz electric pulses with amplitude of 250 MA/M 2 for 100 μs. Such treatment resulted in an increase of time to fracture. The phenomenological model of the process is proposed

  3. Increased durability concrete for generation of pillars power lines

    Directory of Open Access Journals (Sweden)

    Yakovlev Grigory

    2016-01-01

    Full Text Available In this researches multilayered carbon nanotubes of production of the French corporation “Arkema” were used. It has followed features: diameter of 10-15 nanometers and up to 15 microns long. Multilayered carbon nanotubes were used for increasing of physics and technology properties of cement concrete. It was established that at introduction of multilayered carbon nanotubes in amount of 0.006% of the mass led concrete durability increases by 28%, resistance to frost from F200 to F400, tightness to water from W8 to W14.

  4. Tiling as a Durable Abstraction for Parallelism and Data Locality

    Energy Technology Data Exchange (ETDEWEB)

    Unat, Didem [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chan, Cy P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhang, Weiqun [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bell, John [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shalf, John [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-11-18

    Tiling is a useful loop transformation for expressing parallelism and data locality. Automated tiling transformations that preserve data-locality are increasingly important due to hardware trends towards massive parallelism and the increasing costs of data movement relative to the cost of computing. We propose TiDA as a durable tiling abstraction that centralizes parameterized tiling information within array data types with minimal changes to the source code. The data layout information can be used by the compiler and runtime to automatically manage parallelism, optimize data locality, and schedule tasks intelligently. In this study, we present the design features and early interface of TiDA along with some preliminary results.

  5. The Effectiveness of Materials Different with Regard to Increasing the Durability

    Directory of Open Access Journals (Sweden)

    Erofeev Vladimir

    2016-01-01

    Full Text Available The article considers contemporary materials and structures for construction of buildings. The article conducts an economic study of the problem of durability. It addresses the issue of increasing longevity, affecting the term of service to building structures and the efficiency of their operation. Revealed the main factors affecting the durability. It identifies measures its realisation. The method of calculation of economic efficiency of improving the durability of building constructions.

  6. Using Bonding Enamel-Coated Steel Fixtures to Produce More Durable Brick/Masonry Structures

    Science.gov (United States)

    2010-02-01

    Initial tests with enameled metal straps cracked all the test cylinders and straps would not pull out BUILDING STRONG® New Strong Durable Ties...BUILDING STRONG® Using Bonding Enamel -Coated Steel Fixtures to Produce More Durable Brick/Masonry Structures Principal Investigator: Steven C...COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Using Bonding Enamel -Coated Steel Fixtures to Produce More Durable Brick/Masonry

  7. Durable, High Thermal Conductivity Melt Infiltrated Ceramic Composites for Turbine Engine Applications, Phase I

    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...

  8. THE PROBLEM OF ESTIMATING THE DURABILITY OF THE REINFORCED CONCRETE BRIDGES

    Directory of Open Access Journals (Sweden)

    O. I. Lantukh-Liashchenko

    2007-10-01

    Full Text Available This paper presents an assessment and prediction of service life for reinforced concrete bridges. The deterministic and probabilistic approach prediction models of durability are proposed.

  9. Examining the durability of incidentally learned trust from gaze cues.

    Science.gov (United States)

    Strachan, James W A; Tipper, Steven P

    2017-10-01

    In everyday interactions we find our attention follows the eye gaze of faces around us. As this cueing is so powerful and difficult to inhibit, gaze can therefore be used to facilitate or disrupt visual processing of the environment, and when we experience this we infer information about the trustworthiness of the cueing face. However, to date no studies have investigated how long these impressions last. To explore this we used a gaze-cueing paradigm where faces consistently demonstrated either valid or invalid cueing behaviours. Previous experiments show that valid faces are subsequently rated as more trustworthy than invalid faces. We replicate this effect (Experiment 1) and then include a brief interference task in Experiment 2 between gaze cueing and trustworthiness rating, which weakens but does not completely eliminate the effect. In Experiment 3, we explore whether greater familiarity with the faces improves the durability of trust learning and find that the effect is more resilient with familiar faces. Finally, in Experiment 4, we push this further and show that evidence of trust learning can be seen up to an hour after cueing has ended. Taken together, our results suggest that incidentally learned trust can be durable, especially for faces that deceive.

  10. The morphology of durability issues in PEM fuel cells

    International Nuclear Information System (INIS)

    Kundu, S.; Fowler, M.; Simon, L.; Grot, S.

    2004-01-01

    'Full text:' The work presented here examines durability issues in PEM fuel cell materials by examining material morphology and linking morphological features to performance. Scanning electron microscope (SEM) techniques have been able to identify a variety of features on the catalyst layer, each with their own implication to the overall performance and durability of the membrane electrode assembly (MEA). These features include cracking, delamination of the catalyst layer, catalyst clustering, electrolyte clustering, and thickness variations. Links between several of these features and catalyst dispersion conditions was also examined, showing that how the material was manufactured influences the type of morphological features present. The SEM has also been used with accelerated aging techniques to closely examine aging of the gas diffusion layer (GDL). It can be shown that over time the GDL will loose its hydrophobic character and hence become more susceptible to flooding in a fuel cell. The impact of morphological changes were determined using fuel cell models and experimental work. The ultimate aim of this work is to provide material developers with the tools and knowledge necessary to design better materials and therefore bring fuel cells closer to commercialization. (author)

  11. Operational durability of a giant ER valve for Braille display

    Science.gov (United States)

    Luning, Xu; Han, Li; Yufei, Li; Shen, Rong; Kunquan, Lu

    2017-05-01

    The compact configuration of giant ER (electrorheological) valves provides the possibility of realizing a full-page Braille display. The operational durability of ER valves is a key issue in fulfilling a Braille display. A giant ER valve was used to investigate the variations in pressure drops and critical pressure drops of the valves over a long period under some typical operational parameters. The results indicate that neither the pressure drops nor critical pressure drops of giant ER valves show apparent deterioration over a long period. Without ER fluid exchange, a blockage appears in the channel of the valve because the ER structures induced by an external electric field cannot be broken by the Brownian motion of hydraulic oil molecules when the external electric field is removed. Forcing ER fluid flow is an effective and necessary method to keep the channel of the valve unblocked. Thus the operational durability of the valve using giant ER fluids is able to meet the demands of Braille display.

  12. Durability testing with West Valley borosilicate glass composition- Phase II

    International Nuclear Information System (INIS)

    Macedo, P.B.; Finger, S.M.; Barkatt, A.A.; Pegg, I.L.; Feng, X.; Freeborn, W.P.

    1988-06-01

    This report presents the research performed by the Catholic University of America Vitreous State Laboratory (VSL) during FY 1987 in support of the West Valley Demonstration Project (WVDP) nuclear waste vitrification process. A principal objective of this work is the optimization of the glass composition be used for the vitrification of the liquid high-level waste generated at West Valley during nuclear fuel reprocessing. This report discusses (1) the experimental investigations to optimize the reference glass composition (the current leading candidates are WVCM-50 and ATM-10) for the WVDP vitrification process; (2) the systematic experimental investigation performed to determine the effects of compositional variations in WVCM-50 and WV-205 reference glasses on their viscosity and durability (including initial results of long-term leach tests of WVCM-50 under repository conditions); (3) the development of short-time and predictive leach tests; (4) the development of a process model for the West Valley vitrification process which predicts the range of glass compositions which may be encountered during normal operations and the effects of deviations in process control parameters; and (5) the development of product models for predicting the durability and viscosity of nuclear waste glasses

  13. Determination of Stone-Mastic Asphalt Concrete Durability

    Science.gov (United States)

    Yastremsky, D. A.; Abaidullina, T. N.; Chepur, P. V.

    2018-05-01

    The paper is focused on determination of durability of the stone-mastic asphalt (SMA) concrete, containing various stabilizing additives: "Armidon" (authors’ development) and "Viatop". At the first stage of experiments, the APA method was used to determine the rutting in the SMA containing these additives. Strength test for only top layers of asphalt concrete surface is insufficient for the calculation of the pavement fatigue resistance limits. Due to this fact, a comprehensive approach was employed which incorporates the interaction of the surface and subgrade natural soil. To analyze the road surface stress-strain state and to determine the durability margin, a numerical model was used (describes the processes of fatigue life). The model was developed basing on the finite element method (FEM) in the ANSYS program. Conducted studies and numerical calculations allowed obtaining the minimum and maximum stress values in the structure affected zones and in the zones of plastic deformations occurrence in artificial and natural bases. It allows predicting deformation processes during repeated wheel loads caused by moving vehicles. In course of studies, the results of static stresses in the pavement were also obtained.

  14. Fabrication of silver nanoparticle sponge leather with durable antibacterial property.

    Science.gov (United States)

    Liu, Gongyan; Haiqi, Gao; Li, Kaijun; Xiang, Jun; Lan, Tianxiang; Zhang, Zongcai

    2018-03-15

    Leather product with durable antibacterial property is of great interest both from industry and consumer's point of view. To fabricate such functional leather, gallic acid modified silver nanoparticles (GA@AgNPs) were first in situ synthesized with a core-shell structure and an average size of 15.3nm. Due to its hydrophilic gallic acid surface, the GA@AgNPs possessed excellent stability and dispersibility in wide pH range from 3 to 12 and also showed effective antibacterial activity with a minimum inhibitory concentration (MIC) of around 10μgmL -1 . Then, such GA@AgNPs were used as retanning agent to be successfully filled into leather matrix during the leather manufacturing process. Moreover, taking the advantage of its high surface density of carboxyl groups, these GA@AgNPs could be further chemically cross-linked onto collagen fibers by chrome tanning agent. After retanning, the resultant leather was given a "AgNPs sponge" feature with high payload of silver nanoparticles against laundry, exhibiting high and durable antibacterial activity. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Highly efficient and durable TiN nanofiber electrocatalyst supports.

    Science.gov (United States)

    Kim, Hyun; Cho, Min Kyung; Kwon, Jeong An; Jeong, Yeon Hun; Lee, Kyung Jin; Kim, Na Young; Kim, Min Jung; Yoo, Sung Jong; Jang, Jong Hyun; Kim, Hyoung-Juhn; Nam, Suk Woo; Lim, Dong-Hee; Cho, EunAe; Lee, Kwan-Young; Kim, Jin Young

    2015-11-28

    To date, carbon-based materials including various carbon nanostructured materials have been extensively used as an electrocatalyst support for proton exchange membrane fuel cell (PEMFC) applications due to their practical nature. However, carbon dissolution or corrosion caused by high electrode potential in the presence of O2 and/or water has been identified as one of the main failure modes for the device operation. Here, we report the first TiN nanofiber (TNF)-based nonwoven structured materials to be constructed via electrospinning and subsequent two-step thermal treatment processes as a support for the PEMFC catalyst. Pt catalyst nanoparticles (NPs) deposited on the TNFs (Pt/TNFs) were electrochemically characterized with respect to oxygen reduction reaction (ORR) activity and durability in an acidic medium. From the electrochemical tests, the TNF-supported Pt catalyst was better and more stable in terms of its catalytic performance compared to a commercially available carbon-supported Pt catalyst. For example, the initial oxygen reduction performance was comparable for both cases, while the Pt/TNF showed much higher durability from an accelerated degradation test (ADT) configuration. It is understood that the improved catalytic roles of TNFs on the supported Pt NPs for ORR are due to the high electrical conductivity arising from the extended connectivity, high inertness to the electrochemical environment and strong catalyst-support interactions.

  16. Technology of combined chemical-mechanical fabrication of durable coatings

    Science.gov (United States)

    Smolentsev, V. P.; Ivanov, V. V.; Portnykh, A. I.

    2018-03-01

    The article presents the scientific fundamentals of methodology for calculating the modes and structuring the technological processes of combined chemical-mechanical fabrication of durable coatings. It is shown that they are based on classical patterns, describing the processes of simultaneous chemical and mechanical impact. The paper demonstrates the possibility of structuring a technological process, taking into account the systematic approach to impact management and strengthening the reciprocal positive influence of each impact upon the combined process. The combined processes have been planned for fabricating the model types of chemical-mechanical coatings of durable products in machine construction. The planning methodology is underpinned by a scientific hypothesis of a single source of impact management through energy potential of process components themselves, or by means of external energy supply through mechanical impact. The control of it is fairly thoroughly studied in the case of pulsed external strikes of hard pellets, similar to processes of vibroimpact hardening, thoroughly studied and mastered in many scientific schools of Russia.

  17. Progressive Damage Modeling of Durable Bonded Joint Technology

    Science.gov (United States)

    Leone, Frank A.; Davila, Carlos G.; Lin, Shih-Yung; Smeltzer, Stan; Girolamo, Donato; Ghose, Sayata; Guzman, Juan C.; McCarville, Duglas A.

    2013-01-01

    The development of durable bonded joint technology for assembling composite structures for launch vehicles is being pursued for the U.S. Space Launch System. The present work is related to the development and application of progressive damage modeling techniques to bonded joint technology applicable to a wide range of sandwich structures for a Heavy Lift Launch Vehicle. The joint designs studied in this work include a conventional composite splice joint and a NASA-patented Durable Redundant Joint. Both designs involve a honeycomb sandwich with carbon/epoxy facesheets joined with adhesively bonded doublers. Progressive damage modeling allows for the prediction of the initiation and evolution of damage. For structures that include multiple materials, the number of potential failure mechanisms that must be considered increases the complexity of the analyses. Potential failure mechanisms include fiber fracture, matrix cracking, delamination, core crushing, adhesive failure, and their interactions. The joints were modeled using Abaqus parametric finite element models, in which damage was modeled with user-written subroutines. Each ply was meshed discretely, and layers of cohesive elements were used to account for delaminations and to model the adhesive layers. Good correlation with experimental results was achieved both in terms of load-displacement history and predicted failure mechanisms.

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

    International Nuclear Information System (INIS)

    Bocca, P; Grazzini, A; Masera, D

    2011-01-01

    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).

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

    International Nuclear Information System (INIS)

    Seibel, C.K.

    1994-01-01

    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

  20. Revisiting the role of durable polymers in cardiovascular devices.

    Science.gov (United States)

    Mori, Hiroyoshi; Otsuka, Fumiyuki; Gupta, Anuj; Jinnouchi, Hiroyuki; Torii, Sho; Harari, Emanuel; Virmani, Renu; Finn, Aloke V

    2017-11-01

    Polymers are an essential component of drug-eluting stents (DES) used to control drug release but remain the most controversial component of DES technology. There are two types of polymers employed in DES: durable polymer based DES (DP-DES) and biodegradable polymer DES (BP-DES). First-generation DES were exclusively composed of DP and demonstrated increased rates of late stent failure due in part to poor polymer biocompatibility. Newer generations DES use more biocompatible durable polymers or biodegradable polymers. Areas covered: We will cover issues identified with 1st-generation DP-DES, areas of success and failure in 2nd-generation DP-DES and examine the promise and shortcomings of BP-DES. Briefly, fluorinated polymers used in 2nd-generation DP-DES have excellent anti-thrombogenicity and better biocompatibility than 1st-generation DES polymers. However, these devices lead to persistent drug exposure to the endothelium which impairs endothelial function and predisposes towards neoatherosclerosis. Meanwhile, BP-DES has shortened the duration of drug exposure which might be beneficial for endothelial functional recovery leading to less neoatherosclerosis. However, it remains uncertain whether the long-term biocompatibility of bare metal surfaces is better than that of polymer-coated metals. Expert commentary: Each technology has distinct advantages, which can be optimized depending upon the particular characteristics of the patient being treated.

  1. Recyclable magnetite-silver heterodimer nanocomposites with durable antibacterial performance

    Directory of Open Access Journals (Sweden)

    Chunyan Yong

    2018-03-01

    Full Text Available There is a significant need for magnetite-silver nanocomposites that exhibit durable and recyclable antimicrobial activity. In this study, magnetic iron oxide nanoparticles (Fe3O4 NPs coated with ethylenediamine-modified chitosan/polyacrylic acid copolymeric layer (Fe3O4@ECS/PAA were fabricated. Subsequently, directly deposited silver (Ag NPs procedure was carried out to form the antibacterial heterodimers of Fe3O4@ECS/PAA-Ag NPs. The composition and morphology of the resultant nanostructures were confirmed by FT-IR, XRD, TEM and TGA. The overall length of the heterodimers was approximately 45 nm, in which the mean diameter of Fe3O4@ECS/PAA NPs reached up to 35 nm, and that of Ag NPs was around 15 nm. The mass fraction of silver NPs in the nanocomposites was about 63.1%. The obtained Fe3O4@ECS/PAA NPs exhibited good colloidal stability, and excellent response to additional magnetic field, making the NPs easy to recover after antibacterial tests. In particular, the Fe3O4@ECS/PAA-Ag NPs retained nearly 100% biocidal efficiency (106–107 CFU/mg nanoparticles for both Gram-negative bacteria E. coli and Gram-positive bacteria S. aureus throughout ten cycles without washing with any solvents or water, exhibiting potent and durable antibacterial activity.

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

    International Nuclear Information System (INIS)

    Feldman, R.F.; Beaudoin, J.J.; Philipose, K.E.

    1990-01-01

    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 CO 2 . 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

  3. 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.

  4. U.S. DOE Progress Towards Developing Low-Cost, High Performance, Durable Polymer Electrolyte Membranes for Fuel Cell Applications.

    Science.gov (United States)

    Houchins, Cassidy; Kleen, Greg J; Spendelow, Jacob S; Kopasz, John; Peterson, David; Garland, Nancy L; Ho, Donna Lee; Marcinkoski, Jason; Martin, Kathi Epping; Tyler, Reginald; Papageorgopoulos, Dimitrios C

    2012-12-18

    Low cost, durable, and selective membranes with high ionic conductivity are a priority need for wide-spread adoption of polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). Electrolyte membranes are a major cost component of PEMFC stacks at low production volumes. PEMFC membranes also impose limitations on fuel cell system operating conditions that add system complexity and cost. Reactant gas and fuel permeation through the membrane leads to decreased fuel cell performance, loss of efficiency, and reduced durability in both PEMFCs and DMFCs. To address these challenges, the U.S. Department of Energy (DOE) Fuel Cell Technologies Program, in the Office of Energy Efficiency and Renewable Energy, supports research and development aimed at improving ion exchange membranes for fuel cells. For PEMFCs, efforts are primarily focused on developing materials for higher temperature operation (up to 120 °C) in automotive applications. For DMFCs, efforts are focused on developing membranes with reduced methanol permeability. In this paper, the recently revised DOE membrane targets, strategies, and highlights of DOE-funded projects to develop new, inexpensive membranes that have good performance in hot and dry conditions (PEMFC) and that reduce methanol crossover (DMFC) will be discussed.

  5. U.S. DOE Progress Towards Developing Low-Cost, High Performance, Durable Polymer Electrolyte Membranes for Fuel Cell Applications

    Directory of Open Access Journals (Sweden)

    Dimitrios C. Papageorgopoulos

    2012-12-01

    Full Text Available Low cost, durable, and selective membranes with high ionic conductivity are a priority need for wide-spread adoption of polymer electrolyte membrane fuel cells (PEMFCs and direct methanol fuel cells (DMFCs. Electrolyte membranes are a major cost component of PEMFC stacks at low production volumes. PEMFC membranes also impose limitations on fuel cell system operating conditions that add system complexity and cost. Reactant gas and fuel permeation through the membrane leads to decreased fuel cell performance, loss of efficiency, and reduced durability in both PEMFCs and DMFCs. To address these challenges, the U.S. Department of Energy (DOE Fuel Cell Technologies Program, in the Office of Energy Efficiency and Renewable Energy, supports research and development aimed at improving ion exchange membranes for fuel cells. For PEMFCs, efforts are primarily focused on developing materials for higher temperature operation (up to 120 °C in automotive applications. For DMFCs, efforts are focused on developing membranes with reduced methanol permeability. In this paper, the recently revised DOE membrane targets, strategies, and highlights of DOE-funded projects to develop new, inexpensive membranes that have good performance in hot and dry conditions (PEMFC and that reduce methanol crossover (DMFC will be discussed.

  6. Long-term rupture strength as a criterion of operational durability of steam line metal

    International Nuclear Information System (INIS)

    Gofman, Yu.M.

    2000-01-01

    The method for substantiation of the steam line service life prolongation, depending on the achieved level of the metal vulnerability to damage, is proposed. The methodology for evaluating the metal state is developed on the basis of the durability bond with the level of the vulnerability to damage through micropores and the ferrite dislocation structure state. The main changes in the metal at the 1-3 stages of its creep are presented. The micropores are absent at the 1 stage. the micropores of about 0.1 μm in diameter are identified at the beginning of the 2 stage. The ferrite grains on the transition from the 2 to the 3 creep stage are mainly fragmentary. There takes place further micropores growth on the grain boundaries up to 1 - 3 μm. Significant number of recrystallized volumes in the ferrite is observed at the 3 creep stage. The number of micropores of 1 - 3μm in size sharply increases, and, as a rule, chains of micropores are observed. The pores of 5 μm in size are formed at the pre-destruction stage, the fusion whereof leads to microcracks formation [ru

  7. Durability of simulated waste glass: effects of pressure and formation of surface layers

    International Nuclear Information System (INIS)

    Wicks, G.G.; Mosley, W.C.; Whitkop, P.G.; Saturday, K.A.

    1981-01-01

    The leaching behavior of simulated Savannah River Plant (SRP) waste glass was studied at elevated pressures and anticipated storage temperatures. An integrated approach, which combined leachate solution analyses with both bulk and surface studies, was used to study the corrosion process. Compositions of leachates were evaluated by colorimetry and atomic absorption. Used in the bulk and surface analyses were optical microscopy, scanning electron microscopy, x-ray energy spectroscopy, wide-angle x-ray, diffraction, electron microprobe analysis, infrared reflectance spectroscopy, electron spectroscopy for chemical analysis, and Auger electron spectroscopy. Results from this study show that there is no significant adverse effect of pressure, up to 1500 psi and 90 0 C, on the chemical durability of simulated SPR waste glass leached for one month in deionized water. In addition, the leached glass surface layer was characterized by an adsorbed film rich in minor constituents from the glass. This film remained on the glass surface even after leaching in relatively alkaline solutions at elevated pressures at 90 0 C for one month. The sample surface area to volume of leachant ratios (SA/V) was 10:1 cm -1 and 1:10 cm -1 . The corrosion mechanisms and surface and subsurface layers produced will be discussed along with the potential importance of these results to repository storage

  8. Computational Evaluation of Amorphous Carbon Coating for Durable Silicon Anodes for Lithium-Ion Batteries

    Science.gov (United States)

    Hwang, Jeongwoon; Ihm, Jisoon; Lee, Kwang-Ryeol; Kim, Seungchul

    2015-01-01

    We investigate the structural, mechanical, and electronic properties of graphite-like amorphous carbon coating on bulky silicon to examine whether it can improve the durability of the silicon anodes of lithium-ion batteries using molecular dynamics simulations and ab-initio electronic structure calculations. Structural models of carbon coating are constructed using molecular dynamics simulations of atomic carbon deposition with low incident energies (1–16 eV). As the incident energy decreases, the ratio of sp2 carbons increases, that of sp3 decreases, and the carbon films become more porous. The films prepared with very low incident energy contain lithium-ion conducting channels. Also, those films are electrically conductive to supplement the poor conductivity of silicon and can restore their structure after large deformation to accommodate the volume change during the operations. As a result of this study, we suggest that graphite-like porous carbon coating on silicon will extend the lifetime of the silicon anodes of lithium-ion batteries. PMID:28347087

  9. The Antibacterial and Antioxidant Effect of Grape Seed and Green Tea Extracts on Durability of Tilapia

    Directory of Open Access Journals (Sweden)

    Rozita Golvardzadeh

    2016-10-01

    Full Text Available Background: The current study tried to investigate the antioxidant and anti-bacterial effects of green tea and grape seed extract (with a volume of 2% on durability of Tilapia packed inpolyethylene bags, which were kept in cool temperature of 4 ± 1 °C. Methods: Prepared fish were divided into 3 batches: 2 batches were treated by dipping for 30 min in ethanolic of green tea extract (2% v/v and grape seed (2% v/v, respectively, while the third batch was dipped in distilled water as a control sample. The control and treated fish samples were analyzed for microbiological such as total volatile count and psychrotrophic count, and chemical such as thiobarbituric acid (TBA, and free fatty acid (FFA values. The sensory characteristic was over a period of 20 days. Results: The results indicated that the two extracts' treatments delayed significantly (P < 0.05. Lipid oxidation and process of spoilage in comparison with the psychrotrophic bacteria and total viable count control also remained lower than the proposed acceptable limit (7 log CFU/g. According to sensory, chemical, and microbiological analyses results, the treatment of grape seed extract had high quality and enhanced the beneficial effects on sensory characteristics in comparison with other treatments. Conclusions: the present study showed that the grape seed extract and green tea were very effective in extending the shelf life of Tilapia during refrigerated storage.

  10. Tensile strength and durability characteristics of high-performance fiber reinforced concrete

    International Nuclear Information System (INIS)

    Ramadoss, P.; Nagamani, K.

    2008-01-01

    This paper presents investigations towards developing a better understanding of the contribution of steel fibers to the tensile strength of high-performance fiber reinforced concrete (HPFRC). For 32 series of mixes, flexural and splitting tensile strengths were determined at 28 days. The variables investigated were fiber volume fraction (0%, 0.5%, 1% and 1.5% with an aspect of 80), silica fume replacement level (SF/CM=0.05 and 0.10) and matrix composition (w/cm ratios ranging from 0.25 t 0.40). The influence of fiber content in terms of fiber reinforcing index on the flexural and splitting tensile strengths of HPFRC is presented. Comparative studies were performed on the tensile behavior of SFRC measured by two different loading tests: flexural test and splitting test. Based on the test results, using the least square method, empirical expressions were developed to predict 28-day tensile strength of HPFRC in terms of fiber reinforcing index. Durability tests were carried out to examine the performance of the SFRC. Relationship between flexural and splitting tensile strengths has been developed using regression analysis. The experimental values of previous researchers were compared with the values predicted by the empirical equations and the absolute variation obtained was within 6% and 5% for flexural and splitting tensile strengths respectively. (author)

  11. Effect of lead species on the durability of simulated nuclear waste glass

    International Nuclear Information System (INIS)

    Kuchinski, F.A.

    1987-01-01

    It has been shown that the incorporation of lead metal into the corrosion environment reduces the leaching rate of nuclear waste glasses. The present study evaluated the effects of lead metal, oxides, alloys, glasses and soluble species on the corrosion rate of a waste glass. The inherent durability of nuclear waste glasses comes from the about due to the insoluble surface film developed during corrosion. This surface film, enriched with iron, aluminum and calcium acts as a diffusion barrier to further corrosion. Except for PbO 2 , all lead species inhibited glass corrosion due to the formation of a surface film enriched in lead. No corroded glass layer was observed below the lead surface layer. Also, no glass corrosion products were found on the lead surface, except for small amounts of silicon. The transport and deposition of lead on the glass surface appears to be the key factors in preventing glass corrosion. At high glass surface area to volume ratios, the glass corroded considerably at short times since the dissolved lead source could not coat the entire glass surface rapidly enough to prevent continued corrosion. Also, experimental solution values did not agree with thermodynamics model predictions. This suggests that kinetic factors, namely diffusion barriers, are controlling the glass corrosion rate

  12. Computational Evaluation of Amorphous Carbon Coating for Durable Silicon Anodes for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Jeongwoon Hwang

    2015-10-01

    Full Text Available We investigate the structural, mechanical, and electronic properties of graphite-like amorphous carbon coating on bulky silicon to examine whether it can improve the durability of the silicon anodes of lithium-ion batteries using molecular dynamics simulations and ab-initio electronic structure calculations. Structural models of carbon coating are constructed using molecular dynamics simulations of atomic carbon deposition with low incident energies (1–16 eV. As the incident energy decreases, the ratio of sp2 carbons increases, that of sp3 decreases, and the carbon films become more porous. The films prepared with very low incident energy contain lithium-ion conducting channels. Also, those films are electrically conductive to supplement the poor conductivity of silicon and can restore their structure after large deformation to accommodate the volume change during the operations. As a result of this study, we suggest that graphite-like porous carbon coating on silicon will extend the lifetime of the silicon anodes of lithium-ion batteries.

  13. A zwitterionic macro-crosslinker for durable non-fouling coatings.

    Science.gov (United States)

    Wang, Wei; Lu, Yang; Xie, Jinbing; Zhu, Hui; Cao, Zhiqiang

    2016-03-28

    A novel zwitterionic macro-crosslinker was developed and applied to fabricate durable non-fouling coatings on a polyurethane substrate. The zwitterionic macro-crosslinker coating exhibited superior durability over the traditional brush polymer coating and was able to retain its non-fouling property even after weeks of shearing in flowing liquid.

  14. Performance based durability design of a bored tunnel with concrete lining

    NARCIS (Netherlands)

    Vries, H. de; Siemes, A.J.M.

    2002-01-01

    Design for durability is gradually changing from a deem-to-satisfy approach to a performance based approach. The conventional building codes give in principle only construction rules. If these rules are fulfilled, it is assumed that the structure will have an adequate durability. But specifications

  15. The durability of waveguide fibers at cyclic change of loading, temperature and humidity

    International Nuclear Information System (INIS)

    Karimov, S.N.; Sultonov, U.; Shamsidinov, M.I.

    1992-01-01

    Present article is devoted to durability of waveguide fibers at cyclic change of loading, temperature and humidity. The mounting scheme and loading of sample is presented. The dependence of glass fiber durability on number of thermal cycles at various humidity rates was considered. The dependence of number of cycles on maximal loading at cyclic temperature change was studied.

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

    International Nuclear Information System (INIS)

    Vokal, A.; Nachmilner, L.; Wasserbauer, R.; Dohnalek, J.

    2001-01-01

    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

  17. Durability of sealants exposed to outdoor weathering and hot compression cycles

    Science.gov (United States)

    Gregory T. Schueneman; Steven Lacher; Christopher G. Hunt; Christopher C. White; Donald L. Hunston

    2011-01-01

    Sealants play an important role in weatherproofing structures by filling gaps and preventing air and water intrusion. When incorrectly selected or improperly applied, they may fail quickly, compromising durability of the structure. To ensure reliability and prevent the need for costly repairs to structures, it is necessary to measure durability and predict life...

  18. Chemical durability of simulated nuclear glasses containing water

    International Nuclear Information System (INIS)

    Li, H.; Tomozawa, M.

    1995-04-01

    The chemical durability of simulated nuclear waste glasses having different water contents was studied. Results from the product consistency test (PCT) showed that glass dissolution increased with water content in the glass. This trend was not observed during MCC-1 testing. This difference was attributed to the differences in reactions between glass and water. In the PCT, the glass network dissolution controlled the elemental releases, and water in the glass accelerated the reaction rate. On the other hand, alkali ion exchange with hydronium played an important role in the MCC-1. For the latter, the amount of water introduced into a leached layer from ion-exchange was found to be much greater than that of initially incorporated water in the glass. Hence, the initial water content has no effect on glass dissolution as measured by the MCC-1 test

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

    International Nuclear Information System (INIS)

    Kwon, Sung Hun; Yoo, Hong Hee

    2009-01-01

    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

  20. Durability Tests of Ball Valve Prototype with Flowmeter Operation

    Science.gov (United States)

    Rogula, J.; Romanik, G.

    2018-02-01

    The results of the investigation of the prototypical ball valve are presented in this article. The innovation of the tested valve is a ball with a built-in measuring orifice. The valve has been subjected to durability tests. Leakage under three temperatures: ambient, -30°C and +100°C was analyzed. Sealing elements of the valve were tested for roughness and deviation of shape before and after the cycles of operation. Ball valve operation means cycles of open/close. It was planned to perform 1000 cycles at each temperature condition accordingly. Tests of the valve were performed under gas pressure equal to 10 MPa. The research was carried out under the Operational Program "Intelligent Development" (POIR 01.01.01-00-0013 / 15 "Development of devices for measurement of media flow on industrial trunk-lines".

  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. Dynamics of a durable commodity market involving trade at disequilibrium

    Science.gov (United States)

    Panchuk, A.; Puu, T.

    2018-05-01

    The present work considers a simple model of a durable commodity market involving two agents who trade stocks of two different types. Stock commodities, in contrast to flow commodities, remain on the market from period to period and, consequently, there is neither unique demand function nor unique supply function exists. We also set up exact conditions for trade at disequilibrium, the issue being usually neglected, though a fact of reality. The induced iterative system has infinite number of fixed points and path dependent dynamics. We show that a typical orbit is either attracted to one of the fixed points or eventually sticks at a no-trade point. For the latter the stock distribution always remains the same while the price displays periodic or chaotic oscillations.

  3. The efficacy and durability of radon remedial measures

    International Nuclear Information System (INIS)

    Cliff, K.D.; Naismith, S.P.; Scivyer, C.; Stephen, R.

    1994-01-01

    In the UK, over 16,000 homes, from an estimated 100,000, with annual average radon concentrations exceeding the UK Action Level of 200 Bq.m -3 have been discovered. Some 600 householders who have taken action have sought confirmatory measurements from NRPB. Results for 345 such homes are discussed. A number of remedied homes are being remeasured annually to determine the durability of the remedies: results for the first year follow-up measurements are given. In a separate exercise, homes having the highest radon levels known in the UK have been enrolled in a research programme of the Building Research Establishment. The results for 53 homes in which BRE surveyed, designed and supervised remedial work are presented. (author)

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

    International Nuclear Information System (INIS)

    Matsumoto, Yoshinori; Ueno, Hiroto

    2015-01-01

    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)

  5. 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

  6. Durability of Mortar Made with Fine Glass Powdered Particles

    Directory of Open Access Journals (Sweden)

    Rosemary Bom Conselho Sales

    2017-01-01

    Full Text Available Different studies investigate the use of waste glass in Portland cement compounds, either as aggregates or as supplementary cementitious materials. Nevertheless, it seems that there is no consensus about the influence of particle color and size on the behavior of the compounds. This study addresses the influence of cement replacement by 10 and 20% of the colorless and amber soda-lime glass particles sized around 9.5 μm on the performance of Portland cement mortars. Results revealed that the partial replacement of cement could contribute to the production of durable mortars in relation to the inhibition of the alkali-aggregate reaction. This effect was more marked with 20% replacement using amber glass. Samples containing glass microparticles were more resistant to corrosion, in particular those made of colorless glass. The use of colorless and amber glass microparticles promoted a reduction in wear resistance.

  7. Durability properties for adhesively bonded structural aerospace applications

    International Nuclear Information System (INIS)

    Shaffer, D.K.; Davis, G.D.; McNamara, D.K.; Shah, T.K.; Desai, A.

    1992-01-01

    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

  8. A relational approach to durable poverty, inequality and power.

    Science.gov (United States)

    Mosse, David

    2010-01-01

    The article argues for what can be called a 'relational' approach to poverty: one that first views persistent poverty as the consequence of historically developed economic and political relations, and second, that emphasises poverty and inequality as an effect of social categorisation and identity, drawing in particular on the experience of adivasis ("tribals") and dalits ("untouchables") subordinated in Indian society. The approach follows Charles Tilly's Durable Inequality in combining Marxian ideas of exploitation and dispossession with Weberian notions of social closure. The article then draws on the work of Steven Lukes, Pierre Bourdieu and Arjun Appadurai to argue for the need to incorporate a multidimensional conception of power; including not only power as the direct assertion of will but also 'agenda-setting power' that sets the terms in which poverty becomes (or fails to become) politicised, and closely related to power as political representation. This sets the basis for discussion of the politics of poverty and exclusion.

  9. Durability of commercial aircraft and helicopter composite structures

    International Nuclear Information System (INIS)

    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

  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. Some Durability Aspects of Ambient Cured Bottom Ash Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Saravanakumar R.

    2017-09-01

    Full Text Available The present study examines some durability aspects of ambient cured bottom ash geopolymer concrete (BA GPC due to accelerated corrosion, sorptivity, and water absorption. The bottom ash geopolymer concrete was prepared with sodium based alkaline activators under ambient curing temperatures. The sodium hydroxide used concentration was 8M. The performance of BA GPC was compared with conventional concrete. The test results indicate that BA GPC developes a strong passive layer against chloride ion diffusion and provides better protection against corrosion. Both the initial and final rates of water absorption of BA GPC were about two times less than those of conventional concrete. The BA GPC significantly enhanced performance over equivalent grade conventional concrete (CC.

  12. 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.

  13. Durability of PEDOT: PSS-pentacene Schottky diode

    International Nuclear Information System (INIS)

    Kang, K S; Lim, H K; Cho, K Y; Han, K J; Kim, Jaehwan

    2008-01-01

    The durability and failure cause of a polymer Schottky diode made with PEDOT : PSS-pentacene were investigated. A polymer Schottky diode was fabricated by dissolving pentacene in N-methylpyrrolidone (NMP) and mixing with PEDOT : PSS. Pentacene solution having a maximum concentration of approximately 9.7 mmoles was prepared by simply stirring the solution at room temperature for 36 h. As the pentacene concentration increased, the absorption of the broad UV regime increased dramatically. However, absorption peaks of pentacene at 301 and 260 nm were not observed for the PEDOT : PSS-pentacene. A three-layered polymer Schottky diode was fabricated and its current-voltage (I-V) characteristic was evaluated. The current was reduced by 7% in the first 50 min and then stabilized during biased electrical field sweeps. After 500 and 800 min, catastrophic failure occurred. FESEM images revealed that the electrode damage caused catastrophic failure of the Schottky diode. (fast track communication)

  14. Influence of Some Nuclear Waste on The Durability and Mechanical Properties of Borosilicate glass

    International Nuclear Information System (INIS)

    El-Alaily, N.A.

    2003-01-01

    Various glass systems have been shown to be suitable for producing waste glass forms that are thermally and mechanically stable and exhibit good chemical durability. In this study borosilicate glass containing sodium oxide and aluminum oxide was prepared as a host for high level nuclear waste. The glass durability when the samples were immersed either in distilled water or ground water at 70 degree was studied. The density, porosity and mechanical properties were also investigated. The effects of exposing the samples immersed in groundwater to gamma rays in the glass durability and all other mentioned properties were also studied. The results showed that immersing the glass in ground water causing a decrease in the glass durability. The exposure of the glass immersed in ground water to the gamma rays increases the durability of the glass. The mechanical properties of the prepared glass were good. Although these properties decrease for the corroded glass but they were still good

  15. 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.

  16. Performance and durability testing of parabolic trough receivers

    Science.gov (United States)

    Lei, Dongqiang; Fu, Xuqiang; Zhao, Dongming; Yuan, Guofeng; Wang, Zhifeng; Guo, Minghuan

    2017-06-01

    The paper describes the key performance and durability testing facilities of the parabolic trough receiver developed by Institute of Electrical Engineering, Chinese Academy of Sciences. The indoor heat loss test can be applied at 4-7 different temperature levels within 200-550 on receivers. The optical efficiency test bench consists of 12 metal halide lamps as the solar simulator and a 5 m length half-elliptical cylinder reflector with flat end reflectors. 3 ultra-precision temperature sensors are used in receiver each end to get the temperature difference. The residual gas analysis test bench is applied to analyze and predict the vacuum lifetime of the receiver. It can test the variations of composition and partial pressure of residual gases with temperature and time in the receiver annulus space by a high sensitivity quadrupole mass spectrometer gas analyzer. A coating accelerated ageing test bench, which is also used to test the thermal cycle, has been developed. This test bench uses the absorber tube of the recevier as the resistance heater to heat up the whole receiver. The coating lifetime can be predicted by the Arrhenius parameters. For the cycling test, the compressed air is used to directly cool the inner surface of the absorber tube. The thermal cycling test is performed with temperature cycles from 150 °C to 450 °C for 160 cycles. The maximum thermal cycling frequency is 8 cycles per day. The mechanical fatigue test bench is used to test the bellows and the glass-to-metal seals durability at the same time. Both bellows are expanded and compressed to 6.5 mm in turn with 10,000 cycles. A new rotating test bench was also developed to test the thermal efficiency of the receiver.

  17. Durability and service life design of concrete structures. Experiences and the way to prove in The Netherlands

    NARCIS (Netherlands)

    Siemes, A.J.M.; Vrouwenvelder, A.C.W.M.

    2002-01-01

    After the introduction of reinforced concrete it was believed that the material was extremely durable. Soon it was found however, that reinforced concrete could have serious durability problems and that special care should be taken to avoid them. Durability became an issue.

  18. An experimental survey on combined effects of fibers and nanosilica on the mechanical, rheological, and durability properties of self-compacting concrete

    International Nuclear Information System (INIS)

    Beigi, Morteza H.; Berenjian, Javad; Lotfi Omran, Omid; Sadeghi Nik, Aref; Nikbin, Iman M.

    2013-01-01

    Highlights: • We investigate combine effects of fibers and nanosilica on SCC. • The mechanical, rheological, and durability properties were tested and compared. • Microstructural properties of concrete were assessed using AFM and XRD techniques. • Nanosilica and fibers can improve the mechanical properties and durability of SCC. - Graphical abstract: - Abstract: Previous studies have shown that application of fibers in concrete enhances scratching, flexural and tensile strength. Self-Compacting Concrete (SCC) is a highly flowable and coherent concrete able to self-compact under its own weight. On the other hand, nanosilica particles and artificial pozzolans possessing high efficiency in concrete technology can improve structural properties of cement-based materials. Previous studies have suggested self-compacting and fiber-reinforced concretes for more stable and efficient buildings. Therefore, the present study aimed to evaluate the effects of nanosilica and different concrete reinforcing fibers including steel, polypropylene and glass on the performance of concrete. In this study mechanical (compressive, splitting tensile and flexural strength, toughness and modulus of elasticity), rheological (L-Box, slump flow, T50) and durability (resist chloride ion penetration (RCPT) and water absorption) properties are assessed. In addition, microstructural properties of concrete were assessed using Atomic Force Microscopy (AFM) and X-Ray Diffraction (XRD) techniques. Totally, 40 concrete mixes , labeled as A, B, C and D, with nanosilica contents of 0, 2, 4 and 6 weight percent (wt.%) of cement, respectively and three types of reinforcing fibers (steel: 0.2, 0.3 and 0.5 volume percent (v%) and polypropylene: 0.1, 0.15 and 0.2 v% and glass: 0.15, 0.2 and 0.3 v%) were evaluated. The results of the study showed that the presence of both nanosilica and reinforcing fibers in optimal percentages, can improve the mechanical properties and durability of self

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

    International Nuclear Information System (INIS)

    Dragolici, F.; Nicu, M.; Lungu, L.; Turcanu, C.; Rotarescu, Gh.

    2000-01-01

    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

  20. 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

  1. 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.

  2. Comparative Dose Accuracy of Durable and Patch Insulin Infusion Pumps

    Science.gov (United States)

    Jahn, Luis G.; Capurro, Jorge J.; Levy, Brian L.

    2013-01-01

    Background: As all major insulin pump manufacturers comply with the international infusion pump standard EN 60601-2-24:1998, there may be a general assumption that all pumps are equal in insulin-delivery accuracy. This research investigates single-dose and averaged-dose accuracy of incremental basal deliveries for one patch model and three durable models of insulin pumps. Method: For each pump model, discrete single doses delivered during 0.5 U/h basal rate infusion over a 20 h period were measured using a time-stamped microgravimetric system. Dose accuracy was analyzed by comparing single doses and time-averaged doses to specific accuracy thresholds (±5% to ±30%). Results: The percentage of single doses delivered outside accuracy thresholds of ±5%, ±10%, and ±20% were as follows: Animas OneTouch® Ping® (43.2%, 14.3%, and 1.8%, respectively), Roche Accu-Chek® Combo (50.6%, 24.4%, and 5.5%), Medtronic Paradigm® RevelTM/VeoTM (54.2%, 26.7%, and 6.6%), and Insulet OmniPod® (79.1%, 60.5%, and 34.9%). For 30 min, 1 h, and 2 h averaging windows, the percentage of doses delivered outside a ±15% accuracy were as follows: OneTouch Ping (1.0%, 0.4%, and 0%, respectively), Accu-Chek Combo (4.2%, 3.5%, and 3.1%), Paradigm Revel/Veo (3.9%, 3.1%, and 2.2%), and OmniPod (33.9%, 19.9%, and 10.3%). Conclusions: This technical evaluation demonstrates significant differences in single-dose and averaged-dose accuracy among the insulin pumps tested. Differences in dose accuracy were most evident between the patch pump model and the group of durable pump models. Of the pumps studied, the Animas OneTouch Ping demonstrated the best single-dose and averaged-dose accuracy. Further research on the clinical relevance of these findings is warranted. PMID:23911184

  3. 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

  4. Transport durable et développement économique

    Directory of Open Access Journals (Sweden)

    Corinne Meunier

    2006-12-01

    Full Text Available Le transport génère des externalités négatives – notamment environnementales – largement reconnues et dénoncées. Aussi, la référence à la durabilité désormais incontournable dans de nombreux domaines de l’action publique, s’étend inévitablement au transport via la notion de transport durable. C’est notamment en matière de fret que les enjeux de durabilité semblent les plus importants : le taux de croissance du transport des marchandises est en effet plus élevé que celui des passagers et le déséquilibre des parts modales s’y creuse davantage, en défaveur des modes les moins polluants. Dans le transport de fret, c’est la politique européenne des transports qui exerce aujourd'hui une influence déterminante à la fois sur la conduite de la politique française (à toutes les échelles et sur les comportements de la quasi-totalité des acteurs et des opérateurs qui interviennent dans le domaine des transports en France. C’est donc sur le segment des flux de marchandises que notre papier traitera de la traduction européenne des principes fondateurs de la notion de transport durable.Transportation generates negative externalities (especially environmental ones widely known and denounced. Thereby, the reference to sustainability, now incontrovertible in many areas of the public action, reaches transportation via the concept of sustainable transportation. The most important need in sustainability is on freight transportation : carriage growth rate is higher than passenger transportation, and the unevenness between the modal parts is in favour of the most polluting. On freight transportation, the European Union policy exercises a determining opinion, both on the French public policies (at every scale and on most of the actors stepping in the transportation domain in France. The topic of this paper is on the segment of carriage flux and on the European translation of the founding principles of sustainable

  5. Study on durability of natural fibre concrete composites using ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Home; Journals; Bulletin of Materials Science; Volume 33; Issue 6 ... post-yield energy absorption of concrete led to the development of fibre reinforced ... easily available low cost natural fibres are renewable source materials.

  6. Preparation of durable hydrophobic cellulose fabric from water glass and mixed organosilanes

    Science.gov (United States)

    Shang, Song-Min; Li, Zhengxiong; Xing, Yanjun; Xin, John H.; Tao, Xiao-Ming

    2010-12-01

    Durable superhydrophobic cellulose fabric was prepared from water glass and n-octadecyltriethoxysilane (ODTES) with 3-glycidyloxypropyltrimethoxysilane (GPTMS) as crosslinker by sol-gel method. The result showed that the addition of GPTMS could result in a better fixation of silica coating from water glass on cellulose fabric. The silanization of hydrolyzed ODTES at different temperatures and times was studied and optimized. The results showed that silanization time was more important than temperature in forming durable hydrophobic surface. The durability of superhydrophobicity treatment was analyzed by XPS. As a result, the superhydrophobic cotton treated under the optimal condition still remained hydrophobic properties after 50 washing cycles.

  7. Determinants of Long-Term Durable Glycemic Control in New-Onset Type 2 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Kyoung Jin Kim

    2017-08-01

    Full Text Available BackgroundLong-term durable glycemic control is a difficult goal in the management of type 2 diabetes mellitus (T2DM. We evaluated the factors associated with durable glycemic control in a real clinical setting.MethodsWe retrospectively reviewed the medical records of 194 new-onset, drug-naïve patients with T2DM who were diagnosed between January 2011 and March 2013, and were followed up for >2 years. Glycemic durability was defined as the maintenance of optimal glycemic control (glycosylated hemoglobin [HbA1c] <7.0% for 2 years without substitution or adding other glucose-lowering agents. Clinical factors and glycemic markers associated with glycemic durability were compared between two groups: a durability group and a non-durability group.ResultsPatients in the durability group had a higher baseline body mass index (26.1 kg/m2 vs. 24.9 kg/m2 and lower HbA1c (8.6% vs. 9.7% than the non-durability group. The initial choice of glucose-lowering agents was similar in both groups, except for insulin and sulfonylureas, which were more frequently prescribed in the non-durability group. In multiple logistic regression analyses, higher levels of education, physical activity, and homeostasis model assessment of β-cell function (HOMA-β were associated with glycemic durability. Notably, lower HbA1c (<7.0% at baseline and first follow-up were significantly associated with glycemic durability (adjusted odds ratio [OR], 7.48; 95% confidence interval [CI], 2.51 to 22.3 (adjusted OR, 9.27; 95% CI, 1.62 to 53.1, respectively, after adjusting for confounding variables including the types of glucose-lowering agents.ConclusionEarly achievement of HbA1c level within the glycemic target was a determinant of long-term glycemic durability in new-onset T2DM, as were higher levels of education, physical activity, and HOMA-β.

  8. 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.

  9. 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.

  10. Durable Airtightness in Single-Family Dwellings: Field Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Wanyu R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherman, Max H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-06-01

    Durability of building envelope is important to new homes that are increasingly built with improved levels of airtightness. It is also important to weatherized homes such that energy savings from retrofit measures, such as air sealing, are persistent. We presented a comparison of air leakage measurements collected in November 2013 through March 2014, with two sets of prior data collected between 2001-2003 from 17 new homes located near Atlanta, GA, and 17 homes near Boise, ID that were weatherized in 2007-2008. The purpose of the comparison is to determine if there are changes to the airtightness of building envelopes over time. The air leakage increased in all but one of the new homes, with a mean increase of about 25%. The weatherized homes also showed an increase in the mean air leakage (12%). We performed a regression analysis to describe the relationship between prior and current measurements in terms of normalized leakage (NL). The best estimate of the aging factor predicts a 15% increase in NL over ten years. Further analysis using ResDB data (LBNL’s Residential Diagnostic Database) showed the expected changes in air leakage if aging were modeled. These results imply that we should examine the causes of increased leakage and methods to avoid them. This increase in leakage with time should be accounted for in long-term population-wide energy savings estimates, such as those used in ratings or energy savings programs.

  11. Durability and Performance of High Performance Infiltration Cathodes

    DEFF Research Database (Denmark)

    Samson, Alfred Junio; Søgaard, Martin; Hjalmarsson, Per

    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......, varied as: LSC (0.062Ωcm2)cathode was found to depend on the infiltrate firing temperature and is suggested to originate...... of the 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...

  12. Space environment durability of beta cloth in LDEF thermal blankets

    Science.gov (United States)

    Linton, Roger C.; Whitaker, Ann F.; Finckenor, Miria M.

    1993-01-01

    Beta cloth performance for use on long-term space vehicles such as Space Station Freedom (S.S. Freedom) requires resistance to the degrading effects of the space environment. The major issues are retention of thermal insulating properties through maintaining optical properties, preserving mechanical integrity, and generating minimal particulates for contamination-sensitive spacecraft surfaces and payloads. The longest in-flight test of beta cloth's durability was on the Long Duration Exposure Facility (LDEF), where it was exposed to the space environment for 68 months. The LDEF contained 57 experiments which further defined the space environment and its effects on spacecraft materials. It was deployed into low-Earth orbit (LEO) in Apr. 1984 and retrieved Jan. 1990 by the space shuttle. Among the 10,000 plus material constituents and samples onboard were thermal control blankets of multilayer insulation with a beta cloth outer cover and Velcro attachments. These blankets were exposed to hard vacuum, thermal cycling, charged particles, meteoroid/debris impacts, ultraviolet (UV) radiation, and atomic oxygen (AO). Of these space environmental exposure elements, AO appears to have had the greatest effect on the beta cloth. The beta cloth analyzed in this report came from the MSFC Experiment S1005 (Transverse Flat-Plate Heat Pipe) tray oriented approximately 22 deg from the leading edge vector of the LDEF satellite. The location of the tray on LDEF and the placement of the beta cloth thermal blankets are shown. The specific space environment exposure conditions for this material are listed.

  13. Environmental Degradation and Durability of Epoxy-Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Raman P. Singh

    2010-01-01

    Full Text Available This experimental investigation reports on the durability of epoxy-clay nanocomposites upon exposure to multiple environments. Nanocomposites are fabricated by mixing the clay particles using various combinations of mechanical mixing, high-shear dispersion, and ultrasonication. Clay morphology is characterized using X-ray diffraction and transmission electron microscopy. Specimens of both neat epoxy and the epoxy-clay nanocomposite are subjected to two environmental conditions: combined UV radiation and condensation on 3-hour repeat cycle and constant temperature-humidity, for a total exposure duration of 4770 hours. The presence of nanoscale clay inhibits moisture uptake, as demonstrated by exposure to constant temperature-humidity. Nonetheless, both materials lose mass under exposure to combined UV radiation and condensation due to the erosion of epoxy by a synergistic process. Surprisingly, the epoxy-clay specimens exhibit greater mass loss, as compared to neat epoxy. Mechanical testing shows that either environment does not significant affect the flexure modulus of either material. On the other hand, both materials undergo degradation in flexural strength when exposed to either environment. However, the epoxy-clay nanocomposite retains 37% more flexure strength than the neat epoxy after 4072 hours of exposure.

  14. Comparative study of durability test methods for pellets and briquettes

    Energy Technology Data Exchange (ETDEWEB)

    Temmerman, Michaeel; Rabier, Fabienne [Centre wallon de Recherches agronomiques (CRA-W), 146, chaussee de Namur, B-5030, Gembloux (Belgium); Jensen, Peter Daugbjerg [Forest and Landscape, The Royal Veterinary and Agricultural University, Rolighedsvej 23, DK-1958 Frederiksberg C (Denmark); Hartmann, Hans; Boehm, Thorsten [Technologie- und Foerderzentrum fuer Nachwachsende Rohstoffe-TFZ, Schulgasse 18, D-94315 Straubing (Germany)

    2006-11-15

    Different methods for the determination of the mechanical durability (DU) of pellets and briquettes were compared by international round robin tests including different laboratories. The DUs of five briquette and 26 pellet types were determined. For briquettes, different rotation numbers of a prototype tumbler and a calculated DU index are compared. For pellets testing, the study compares two standard methods, a tumbling device according to ASAE S 269.4, the Lignotester according to ONORM M 7135 and a second tumbling method with a prototype tumbler. For the tested methods, the repeatability, the reproducibility and the required minimum number of replications to achieve given accuracy levels were calculated. Additionally, this study evaluates the relation between DU and particle density. The results show for both pellets and briquettes, that the measured DU values and their variability are influenced by the applied method. Moreover, the variability of the results depend on the biofuel itself. For briquettes of DU above 90%, five replications lead to an accuracy of 2%, while 39 replications are needed to achieve an accuracy of 10%, when briquettes of DU below 90% are tested. For pellets, the tumbling device described by the ASAE standard allows to reach acceptable accuracy levels (1%) with a limited number of replications. Finally, for the tested pellets and briquettes no relation between DU and particle density was found. (author)

  15. PEMFC for aeronautic applications: A review on the durability aspects

    Science.gov (United States)

    Dyantyi, Noluntu; Parsons, Adrian; Sita, Cordellia; Pasupathi, Sivakumar

    2017-11-01

    Proton exchange membrane fuel cells (PEMFC) not only offer more efficient electrical energy conversion, relative to on-ground/backup turbines but generate by-products useful in aircraft such as heat for ice prevention, deoxygenated air for fire retardation and drinkable water for use on-board. Consequently, several projects (e.g. DLR-H2 Antares and RAPID2000) have successfully tested PEMFC-powered auxiliary unit (APU) for manned/unmanned aircraft. Despite the progress from flying PEMFC-powered small aircraft with 20 kW power output as high as 1 000 m at 100 km/h to 33 kW at 2 558 m, 176 km/h [1, 2, 3], durability and reliability remain key challenges. This review reports on the inadequate understanding of behaviour of PEMFC under aeronautic conditions and the lack of predictive methods conducive for aircraft that provide real-time information on the State of Health of PEMFCs. -To minimize performance loss due to high altitude and inclination by adjusting cathode stoichiometric ratio. -To improve quality of oxygen-depleted air by controlling operating temperature and stoichiometric ratio. -Need to devise real time prediction methods conducive for determining PEMFC SoH in aircraft.

  16. Electro-active paper for a durable biomimetic actuator

    International Nuclear Information System (INIS)

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

    2009-01-01

    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

  17. 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

  18. 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

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

    International Nuclear Information System (INIS)

    Nahum, T.; Dodiuk, H.; Dotan, A.; Kenig, S.; Lellouche, J. P.

    2015-01-01

    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 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 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

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

    International Nuclear Information System (INIS)

    Kalb, P.D.; Heiser, J.H. III; Pietrzak, R.; Colombo, P.

    1991-01-01

    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

  1. The durability of examination gloves used on intensive care units.

    Science.gov (United States)

    Hübner, Nils-Olaf; Goerdt, Anna-Maria; Mannerow, Axel; Pohrt, Ute; Heidecke, Claus-Dieter; Kramer, Axel; Partecke, Lars Ivo

    2013-05-20

    The use of examination gloves is part of the standard precautions to prevent medical staff from transmission of infectious agents between patients. Gloves also protect the staff from infectious agents originating from patients. Adequate protection, however, depends on intact gloves. The risk of perforation of examination gloves is thought to correlate with duration of wearing, yet, only very few prospective studies have been performed on this issue. A total number of 1500 consecutively used pairs of examination gloves of two different brands and materials (latex and nitrile) were collected over a period of two months on two ICU's. Used gloves were examined for micro perforations using the "water-proof-test" according to EN 455-1. Cox-regression for both glove types was used to estimate optimal changing intervals. Only 26% of gloves were worn longer than 15 min. The total perforation rate was 10.3% with significant differences and deterioration of integrity of gloves between brands (pgloves show marked differences in their durability that cannot be predicted based on the technical data routinely provided by the manufacturer. Based on the increase of micro perforations over time and the wearing behavior, recommendations for maximum wearing time of gloves should be given. Changing of gloves after 15 min could be a good compromise between feasibility and safety. HCWs should be aware of the benefits and limitations of medical gloves. To improve personal hygiene hand disinfection should be further encouraged.

  2. Durability of recycled aggregate concrete using pozzolanic materials.

    Science.gov (United States)

    Ann, K Y; Moon, H Y; Kim, Y B; Ryou, J

    2008-01-01

    In this study, pulverized fuel ash (PFA) and ground granulated blast furnace slag (GGBS) were used to compensate for the loss of strength and durability of concrete containing recycled aggregate. As a result, 30% PFA and 65% GGBS concretes increased the compressive strength to the level of control specimens cast with natural granite gravel, but the tensile strength was still lowered at 28 days. Replacement with PFA and GGBS was effective in raising the resistance to chloride ion penetrability into the concrete body, measured by a rapid chloride ion penetration test based on ASTM C 1202-91. It was found that the corrosion rate of 30% PFA and 65% GGBS concretes was kept at a lower level after corrosion initiation, compared to the control specimens, presumably due to the restriction of oxygen and water access. However, it was less effective in increasing the chloride threshold level for steel corrosion. Hence, it is expected that the corrosion time for 30% PFA and 65% GGBS concrete containing recycled aggregate mostly equates to the corrosion-free life of control specimens.

  3. Environmental Degradation and Durability of Epoxy-Clay Nanocomposites

    International Nuclear Information System (INIS)

    Singh, R.P.; Zunjarrao, S.C.; Pandey, G.; Khait, M.; Korach, C.S.

    2010-01-01

    This experimental investigation reports on the durability of epoxy-clay nanocomposites upon exposure to multiple environments. Nanocomposites are fabricated by mixing the clay particles using various combinations of mechanical mixing, high-shear dispersion, and ultrasonication. Clay morphology is characterized using X-ray diffraction and transmission electron microscopy. Specimens of both neat epoxy and the epoxy-clay nanocomposite are subjected to two environmental conditions: combined UV radiation and condensation on 3-hour repeat cycle and constant temperature-humidity, for a total exposure duration of 4770 hours. The presence of nanoscale clay inhibits moisture uptake, as demonstrated by exposure to constant temperature-humidity. Nonetheless, both materials lose mass under exposure to combined UV radiation and condensation due to the erosion of epoxy by a synergistic process. Surprisingly, the epoxy-clay specimens exhibit greater mass loss, as compared to neat epoxy. Mechanical testing shows that either environment does not significant affect the flexure modulus of either material. On the other hand, both materials undergo degradation in flexural strength when exposed to either environment. However, the epoxy-clay nanocomposite retains 37% more flexure strength than the neat epoxy after 4072 hours of exposure.

  4. Transparent superwetting nanofilms with enhanced durability at model physiological condition

    Science.gov (United States)

    Hwangbo, Sunghee; Heo, Jiwoong; Lin, Xiangde; Choi, Moonhyun; Hong, Jinkee

    2016-01-01

    There have been many studies on superwetting surfaces owing to the variety of their potential applications. There are some drawbacks to developing these films for biomedical applications, such as the fragility of the microscopic roughness feature that is vital to ensure superwettability. But, there are still only a few studies that have shown an enhanced durability of nanoscale superwetting films at certain extreme environment. In this study, we fabricated intrinsically stable superwetting films using the organosilicate based layer-by-layer (LbL) self-assembly method in order to control nano-sized roughness of the multilayer structures. In order to develop mechanically and chemically robust surfaces, we successfully introduced polymeric silsesquioxane as a building block for LbL assembly with desired fashion. Even in the case that the superhydrophobic outer layers were damaged, the films maintained their superhydrophobicity because of the hydrophobic nature of their inner layers. As a result, we successfully fabricated superwetting nano-films and evaluated their robustness and stability. PMID:26764164

  5. Durability of Gamma Irradiated Polymer Impregnated Blended Cement Pastes

    International Nuclear Information System (INIS)

    Khattab, M.M.; Abdel-Rahman, H.A.; Younes, M.M.

    2010-01-01

    This study is focusing on durability and performance of the neat blended cement paste as well as those of the polymer-impregnated paste towards seawater and various concentrations of magnesium sulfate solutions up to 6 months of curing. The neat blended cement paste is prepared by a partial substitution of ordinary Portland cement with 5% of active rice husk ash (RHA). These samples were cured under tap water for 7 days. Similar samples were impregnated with unsaturated polyester resin (UPE) and subjected to various doses of gamma rays ranging from 10 to 50 kGy. The results showed that the irradiated impregnated specimens gave higher values of compressive strength than the neat blended cement paste specimens. On immersing the neat blended cement specimens and polymer impregnated specimens especially that irradiated at 30 kGy in seawater and different concentrations of magnesium sulfate solutions up to 6 months of curing, the results showed that the polymer impregnated blended cement (OPC-RHA-UPE) paste have a good resistance towards aggressive media as compared to the neat blended cement (OPC-RHA) paste. The results also indicated that the sea water has a greater corrosive effect than the magnesium sulfate solutions. These results were confirmed by scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP)

  6. Integrated Monitoring System for Durability Assessment of Concrete Bridges

    Directory of Open Access Journals (Sweden)

    Cristian-Claudiu Comisu

    2005-01-01

    Full Text Available An ageing and deteriorating bridge stock presents the bridge owners with the growing challenge of maintaining the structures at a satisfactory level of safety, performance and aesthetic appearance within the allocated budgets. This task calls for optimized bridge management based on efficient methods of selecting technical and economical optimal maintenance and rehabilitation strategies. One of the crucial points in the assessment of the current condition and future development and performance. Selecting the optimal maintenance and rehabilitation strategy within the actual budget is a key point in bridge management for which an accurate assessment of performance and deterioration rate is necessary. For this assessment, the use of integrated monitoring system has several advantages compared to the traditional approach of scattered visual inspections combined with occasional on site testing with portable equipment and laboratory testing of collected samples. For this reason, attention is more focusing on the development of permanent integrated monitoring system for durability assessment of concrete bridges. It is estimated that with the implementation of such integrated monitoring systems, it should be possible to reduce the operating costs of inspections and maintenance by 25% and the operator of the structures will be able to take protective actions before damaging processes start. This paper indentifies the main bridge owner requirements to integrated monitoring systems and outlines how monitoring systems may be used for performance and deterioration rate assessment to establish a better basis for selecting the optimal maintenance and rehabilitation strategy.

  7. Estudo da durabilidade de argamassas alternativas contendo resíduos Durability study of alternative mortars containing wastes

    Directory of Open Access Journals (Sweden)

    J. Farias Filho

    2011-12-01

    Full Text Available O interesse pela preservação dos recursos naturais e a busca pelo desenvolvimento sustentável tem despertado interesse de um grande número de pesquisadores visando obter materiais de construção não convencionais. Dentre essas possibilidades, destacam-se os resíduos produzidos pela construção civil e pela indústria de beneficiamento de granito, em virtude do volume gerado e os impactos ambientais do seu descarte inadequado. Este trabalho tem como objetivo estudar a durabilidade das argamassas alternativas incorporadas com resíduos de construção civil e da serragem do granito. Para quantificar a durabilidade dos materiais estudados, foram realizados ensaios de envelhecimento natural e ensaios de envelhecimento acelerado através de ciclos de molhagem e secagem, visando simular condições de utilização e avaliar sua degradação. Nos estudos da durabilidade foram utilizados traços de argamassas para alvenaria de elevação, com percentagens de substituição, em peso, da cal por resíduo de 30% e 50%. Os resultados para o envelhecimento natural evidenciaram o comprometimento da durabilidade do material após 60 dias com redução no comportamento mecânico, sendo os melhores resultados para os corpos-de-prova com 30% e 50% de resíduo de construção. No envelhecimento acelerado, para os tratamentos adotados, os resultados evidenciaram a ação da formação de silicoaluminatos de cálcio e potássio que favoreceram um aumento do comportamento mecânico e, além disso, não foi observado o comprometimento da sua durabilidade.The preservation of natural resources and search for sustainable development are increase in interest by the researchers with the aim to obtain knowledge of non conventional materials. Among these possibilities stand out the recycling of residues from civil construction and from granite industry, which are producers of large amount of residues and causing great environmental impacts. The aim of this work is to

  8. The effect of compositional parameters on the TCLP and PCT durability of environmental glasses

    International Nuclear Information System (INIS)

    Resce, J.L.; Overcamp, T.J.

    1995-01-01

    The relationship between glass composition and the chemical durability of environmental waste glass is very important for both the development of glass formulations and the prediction of glass durability for process control. The development of such a model is extremely difficult for several reasons. Firstly, chemical durability is dependent upon the type of leach test employed; the leach tests themselves being only crude approximations of actual environmental conditions or long term behavior. Secondly, devitrification or crystallinity can also play a major role in durability, but is much more difficult to quantify. Lastly, the development of any one model for all glass types is impractical because of the wide variety of wastestreams, the heterogeneity of the wastestreams, and the large variety of components within each wastestream. Several ongoing efforts have been directed toward this goal, but as yet, no model has been proven acceptable

  9. Next Generation , Lightweight, Durable Boot Materials to Provide Active & Passive Thermal Protection, Phase I

    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)...

  10. 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).

  11. Sports, genre et developpement durable : l'heritage d'une ...

    African Journals Online (AJOL)

    Sports, genre et developpement durable : l'heritage d'une distribution ... to new populations in situation of confrontation with the difference that Goffman (1975) ... and women (gender), maintain the sports field and behind the appearance of a ...

  12. Experimental research on durability of recycled aggregate concrete under freeze- thaw cycles

    Science.gov (United States)

    Cheng, Yanqiu; Shang, Xiaoyu; Zhang, Youjia

    2017-07-01

    The freeze-thaw durability of recycled aggregate concrete has significance for the concrete buildings in the cold region. In this paper, the rapid freezing and thawing cycles experience on recycle aggregate concrete was conducted to study on the effects of recycle aggregate amount, water-binder ratio and fly ash on freeze-thaw durability of recycle aggregate concrete. The results indicates that recycle aggregate amount makes the significant influence on the freeze-thaw durability. With the increase of recycled aggregates amount, the freeze-thaw resistance for recycled aggregate concrete decreases. Recycled aggregate concrete with lower water cement ratio demonstrates better performance of freeze-thaw durability. It is advised that the amount of fly ash is less than 30% for admixture of recycled aggregates in the cold region.

  13. Durability assessment of recycled concrete aggregates for use in new concrete.

    Science.gov (United States)

    2012-06-01

    The primary goal of this research project was to investigate the long-term durability of concrete incorporating : recycled concrete aggregate (RCA) through accelerated laboratory testing. Overall it was found that modifications to : standard aggregat...

  14. 40 CFR 86.094-13 - Light-duty exhaust durability programs.

    Science.gov (United States)

    2010-07-01

    ... conformity for the affected engine families void ab initio. (e) Alternative Service Accumulation Durability... shall propose sample sizes, recruitment procedures, testing procedures, optional provisions for the...) of this section, the manufacturer shall provide reliability data that shows to the Administrator's...

  15. Neonatal GLP1R activation limits adult adiposity by durably altering hypothalamic architecture

    Directory of Open Access Journals (Sweden)

    Andrea V. Rozo

    2017-07-01

    Conclusion: These observations suggest that the acute activation of GLP1R in neonates durably alters hypothalamic architecture to limit adult weight gain and adiposity, identifying GLP1R as a therapeutic target for obesity prevention.

  16. Durability and Reliability of Large Diameter HDPE Pipe for Water Main Applications (Web Report 4485)

    Science.gov (United States)

    Research validates HDPE as a suitable material for use in municipal piping systems, and more research may help users maximize their understanding of its durability and reliability. Overall, corrosion resistance, hydraulic efficiency, flexibility, abrasion resistance, toughness, f...

  17. Rapid Manufacturing of Durable, Cost-Effective Ceramic Matrix Composites for High Temperature Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Hypersonic vehicles require durable and cost-effective hot structures that do not impose weight penalties such as those associated with the use of non-structural...

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

    DEFF Research Database (Denmark)

    Petrella, Ivan; Santoro, Emiliano

    of production in both sectors, according to an input-output matrix calibrated on the US economy. As shown in a number of recent contributions, this roundabout technology allows us to reconcile standard two-sector New Keynesian models with the empirical evidence showing co-movement between durable and non......-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...

  19. Monitoring the Durability Performance of Concrete in Nuclear Waste Containment. Technical Progress Report No. 3

    International Nuclear Information System (INIS)

    Ulm, Franz-Josef

    2000-01-01

    OAK-B135 Monitoring the Durability Performance of Concrete in Nuclear Waste Containment. Technical Progress Report No. 3(NOTE: Part II A item 1 indicates ''PAPER'', but a report is attached electronically)

  20. Evaluation of curing compound application time on concrete surface durability : [brief].

    Science.gov (United States)

    2015-05-01

    Roadways that are both durable and aesthetically pleasing are primary goals of Wisconsin : Department of Transportation (WisDOT) paving projects. Recently, Portland Cement Concrete : (PCC) pavement projects constructed by WisDOT have experienced incr...

  1. Concrete pavement mixture design and analysis (MDA) : assessment of air void system requirements for durable concrete.

    Science.gov (United States)

    2012-06-01

    Concrete will suffer frost damage when saturated and subjected to freezing temperatures. Frost-durable concrete can be produced if a : specialized surfactant, also known as an air-entraining admixture (AEA), is added during mixing to stabilize micros...

  2. Effect of wet curing duration on durability parameters of hydraulic cement concretes.

    Science.gov (United States)

    2010-01-01

    Hydraulic cement concrete slabs were cast and stored outdoors in Charlottesville, Virginia, to study the impact of wet curing duration on durability parameters. Concrete mixtures were produced using portland cement, portland cement with slag cement, ...

  3. Durability of saw-cut joints in plain cement concrete pavements.

    Science.gov (United States)

    2011-01-01

    The objective of this project was to evaluate factors influencing the durability of the joints in portland cement concrete : pavement in the state of Indiana. Specifically this work evaluated the absorption of water, the absorption of deicing solutio...

  4. METHODS OF THE APPROXIMATE ESTIMATIONS OF FATIGUE DURABILITY OF COMPOSITE AIRFRAME COMPONENT TYPICAL ELEMENTS

    Directory of Open Access Journals (Sweden)

    V. E. Strizhius

    2015-01-01

    Full Text Available Methods of the approximate estimations of fatigue durability of composite airframe component typical elements which can be recommended for application at the stage of outline designing of the airplane are generated and presented.

  5. Eco-imposition du capital, emploi et développement industriel durable

    Directory of Open Access Journals (Sweden)

    Bernard Dupont

    2010-09-01

    Full Text Available En remplaçant la part des cotisations sociales à la charge de l’employeur par un éco-impôt sur le capital polluant, l’Etat peut inciter les entreprises à investir dans les trajectoires technologiques de la durabilité. Cet article expose un modèle macroéconomique à trois facteurs qui montre comment la fixation conjointe et combinée du taux de cotisations sociales et du taux d'éco-impôt peut assurer la stabilité globale des prix, garantir la neutralité budgétaire et conserver en l’état la compétitivité prix. Contrôlée par le ministère du développement durable, la déformation de la fonction de production provoquée par une fiscalité directe favorable au capital non polluant et au travail augmente le volume de l’emploi et améliore la qualité environnementale sans détériorer la compétitivité ni déséquilibrer les comptes sociaux.Replacing the welfare cost by an eco-taxation based on polluting capital can incite companies to invest in the technological trajectories for sustainability. This paper proposes a macroeconomic three factors model in which the jointed and combined determination of welfare cost and eco-taxation rates can maintain the global price stability, guarantees the budget balance of fiscal transfers and keeps the state of the competitiveness price as it was before. Controlled by the ministry of sustainable development, the deformation of the function of production, caused by a direct tax system favorable to the non-polluting capital and to the labour, increases the employment and improves the environmental quality without negative effects on competitiveness and social accounts.

  6. Will It Every Fly? Modeling the Takeoff of Really New Consumer Durables

    OpenAIRE

    Peter N. Golder; Gerard J. Tellis

    1997-01-01

    A consistent pattern observed for really new household consumer durables is a takeoff or dramatic increase in sales early in their history. The takeoff tends to appear as an elbow-shaped discontinuity in the sales curve showing an average sales increase of over 400%. In contrast, most marketing textbooks as well as diffusion models generally depict the growth of new consumer durables as a smooth sales curve. Our discussions with managers indicate that they have little idea about the takeoff a...

  7. Highly Sensitive, Transparent, and Durable Pressure Sensors Based on Sea-Urchin Shaped Metal Nanoparticles.

    Science.gov (United States)

    Lee, Donghwa; Lee, Hyungjin; Jeong, Youngjun; Ahn, Yumi; Nam, Geonik; Lee, Youngu

    2016-11-01

    Highly sensitive, transparent, and durable pressure sensors are fabricated using sea-urchin-shaped metal nanoparticles and insulating polyurethane elastomer. The pressure sensors exhibit outstanding sensitivity (2.46 kPa -1 ), superior optical transmittance (84.8% at 550 nm), fast response/relaxation time (30 ms), and excellent operational durability. In addition, the pressure sensors successfully detect minute movements of human muscles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  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. THE RELEVANCE OF ELECTRONIC COMMERCE FOR DURABLE DEVELOPMENT. CHALLENGES FOR ROMANIA

    OpenAIRE

    Assist. Ph.D Student Maruntelu Irina

    2009-01-01

    This article aims to approach the topic of the electronic commerce considering the context of the durable development, without exclusively limiting to the economic dimension of sustainable development. This paper aims to offer a vision on the e-commerce based on an optimistic approach of the reconciliation between economic growth and durable development, but moderate by the current realities (digital divide between countries/regions, economic crisis etc). Furthermore, by identifying some of t...

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

    International Nuclear Information System (INIS)

    2007-01-01

    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

  11. Durability testing of the high-capacity GA-4/GA-9 trailer

    International Nuclear Information System (INIS)

    Zimmer, A.; Lyon, T.

    1995-01-01

    GA designed trailers to transport the GA-4 and GA-9 LWT from-reactor spent nuclear fuel shipping casks. GA designed and fabricated the GA-9 trailer to ANSI N14.30 requirements and is now performing a durability test at the AlliedSignal Automotive Proving Grounds. The trailer, simulated cask and tractor. The test program objective is to evaluate and improve, as necessary, the trailer's durability, reliability and performance

  12. Experimental research on the durability cutting tools for cutting-off steel profiles

    Directory of Open Access Journals (Sweden)

    Cristea Alexandru

    2017-01-01

    Full Text Available The production lines used for manufacturing U-shaped profiles are very complex and they must have high productivity. One of the most important stages of the fabrication process is the cutting-off. This paper presents the experimental research and analysis of the durability of the cutting tools used for cutting-off U-shaped metal steel profiles. The results of this work can be used to predict the durability of the cutting tools.

  13. Evolution of Durable High-Strength Flowable Mortar Reinforced with Hybrid Fibers

    OpenAIRE

    Dawood, Eethar Thanon; Ramli, Mahyuddin

    2012-01-01

    The production and use of durable materials in construction are considered as one of the most challenging things for the professional engineers. Therefore, this research was conducted to investigate the mechanical properties and the durability by using of different percentages of steel fiber with high-strength flowable mortar (HSFM) and also the use of the hybridization of steel fibers, palm fibers, and synthetic fiber (Barchip). Different experimental tests (compressive strength, splitting t...

  14. The effect of a finite time horizon in the durable good monopoly problem with atomic consumers

    OpenAIRE

    Berbeglia, Gerardo; Sloan, Peter; Vetta, Adrian

    2014-01-01

    A durable good is a long-lasting good that can be consumed repeatedly over time, and a duropolist is a monopolist in the market of a durable good. In 1972, Ronald Coase conjectured that a duropolist who lacks commitment power cannot sell the good above the competitive price if the time between periods approaches zero. Coase's counterintuitive conjecture was later proven by Gul et al. (1986) under an infinite time horizon model with non-atomic consumers. Remarkably, the situation changes drama...

  15. Moving towards a virtual durability of vehicles; Auf dem Weg zur virtuellen Festigkeit im Fahrzeugbau

    Energy Technology Data Exchange (ETDEWEB)

    Heuler, P.; Birk, O.; Beste, A. [Audi AG, Ingolstadt (Germany). Abt. I/EG-32

    2001-04-01

    The dualism of experimental and virtual durability assessment is addressed. The possibilities and limitations of the virtual concepts are discussed with regard to the different steps of the durability assessment. It is outlined from a user's point of view where the use of these concepts is presently seen. It is important to rate the potentials of each step ranging from the definition of load requirements to the life time calculation. (orig.)

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

    International Nuclear Information System (INIS)

    Huang Wenqi; Xing Yanjun; Yu Yunyi; Shang Songmin; Dai Jinjin

    2011-01-01

    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 137.6 o (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.

  17. Application of the cementitious grouts on stability and durability of semi flexible bituminous mixtures

    Science.gov (United States)

    Karami, Muhammad

    2017-11-01

    This paper describes the results of laboratory test for a high durability semi flexible bituminous mixtures (SFBM). The SFBM consists of an open asphalt structure where a high strength mortar is penetrated into the air voids of the bituminous mixtures. The SFBM combines the cement concrete's strength and the asphalt material flexibility. The objective of this study is to involve in the determination of stability and durability of SFBM by located the position of the specimen on an exposed area for 7, 90, 180 and 240 days. The performance of the SFBM was assessed using Marshall and wheel tracking apparatus. Total 18 specimens were prepared and examined for both of test. The Marshall specimens were cylindrical with dimension of 10.16 cm in diameter and 6.35 cm in high. For wheel tracking test, the specimens consisted of slabs with dimension of 30 cm in length, 30 cm in width and 5 cm in height. The results indicated that the first durability index and second durability index increased significantly. For Marshall test, the first and second durability index increased about 0.9% per day and 52.3%, respectively. However, for wheel tracking test, the first and second durability index increased about 1.9% per day and 119%, respectively.

  18. 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

  19. Evaluation of durability of SSCs injected with seawater

    International Nuclear Information System (INIS)

    2012-01-01

    At the units 1 to 4 in the Fukushima Daiichi Nuclear Power Plant, seawater was injected into reactor pressure vessels and spent fuel pools in order to cool down nuclear fuel is after the disaster of the 2011 off the Pacific Coast of Tohoku Earthquake and Tsunami. Therefore, for fuel cladding tubes exposed to seawater and piping items to pour seawater into a nuclear reactor, it was necessary to evaluate structural integrity under the seawater environment. And then, JNES carried out the safety research of 'Evaluation of Durability of SSCs injected with Seawater' in FY2011. The contents and the results obtained from the search are as follows; (1) For the pipes and nuclear reactor containment vessels, corrosion tests under high temperature seawater at 50degC and 80degC were carried out for the carbon steel that corrosion resistance was less. The data of relationship between a dipping time upto 1,500h and a corrosion rate were obtained as parameters at chloride ion (CI - ) content and the temperature of the seawater. As the results, the corrosion rate was almost 0.1 mm/y for the carbon steel SGV480. No significant influence of CT - content and the temperature of the seawater was confirmed. (2) Corrosion tests were carried out to obtain the relations of time and corrosion under different CI - content conditions for the simulated fuel rod specimens in seawater at 90degC for durations upto 1,200h. As the results, very little corrosion was observed on Zry-2 cladding tube. Brown rust was slightly appeared on the nut made of stainless steel and the lower tie plate made of cast stainless steel. Thinning and corrosion pit were not observed. (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 two water repelents applied to granite

    Directory of Open Access Journals (Sweden)

    Rivas, T.

    1998-06-01

    Full Text Available The durability of two water-repellents for granitic stonework was determined. Weathered and sound samples of granites widely used in building construction and restoration in Galicia (NW Spain were treated with water repellents of known efficacy, and then subjected to two artificial weathering tests: prolonged exposure to UV light, and sodium sulphate crystallization cycles. In both tests, but especially in the salt crystallization cycles, both treatments rapidly lost their water-repellency. Furthermore, the hydrophobic layer of water repellent impeded salt mobility, favouring fissuration parallel to the treated surface, which was eventually shed in the form of a plaque.

    Se presentan los resultados de la durabilidad de dos tratamientos de hidrofugación aplicados a rocas graníticas ampliamente utilizados en la construcción de edificios en Galicia (Noroeste de España. Tras la evaluación de la eficacia de dichos tratamientos, cuyos resultados se presentaron en un trabajo anterior, se someten las muestras tratadas a dos ensayos diferentes de envejecimiento acelerado: ciclos de exposición a la luz ultravioleta y ciclos de cristalización de sulfato de sodio. Los productos hidrofugantes muestran una escasa resistencia a ambos ensayos, sobre todo a los ciclos de cristalización de sulfato de sodio; esta débil durabilidad se manifiesta en una rápida pérdida de sus propiedades hidrofugantes. Así mismo, se observa que la presencia de la capa hidrófoba en la piedra funciona como una barrera frente a la movilidad de sales, lo que ocasiona el total desprendimiento de aquella y un fuerte deterioro del material rocoso.

  2. Durability of building stones against artificial salt crystallization

    Science.gov (United States)

    Min, K.; Park, J.; Han, D.

    2005-12-01

    Salts have been known as the most powerful weathering agents, especially when combined with frost action. Salt crystallization test along with freezing-thawing test and acid immersion test was carried out to assess the durability of building stones against weathering. Granite, limestone, marble and basalt were sampled from different quarries in south Korea for this study. One cycle of artificial salt crystallization test was composed of immersion of cored rock specimens in oversaturated solutions of CaCl2, KCl, NaCl and Na2SO4, respectively for 15 hours and successive drying in an oven of 105°C for 3 hours and cooling at room temperature. Tests were performed up to 30 cycles, and specific gravity and ultrasonic velocity were measured after experiencing every 10 cycles and uniaxial compressive strength was measured only after 30 cycles. During the repeated Na2SO4 salt crystallization, some rock samples were gradually deformed excessively and burst after 20 to 30 cycles of test. The variation patterns of physical properties during the salt crystallization tests are too variable to generalize the effect of salt weathering on physical properties but limestone, marble and basalt samples showed relatively greater change of physical properties than granite samples. The recrystallized salts were well observed in the cracks of rock samples through the scanning electron microscope. In the all salt crystallization tests, apparent specific gravities for all tested samples increased generally but not so significantly due to recrystallization of salts. It can be inferred that filling the pores with salt crystals cause the increase of ultrasonic velocity during the early stage of salt crystallization and then in later stages the repeated cycles of salt crystallization result in development of cracks leading decrease of ultrasonic velocity for some rock samples.

  3. Rock as a construction material: durability, deterioration and conservation

    Directory of Open Access Journals (Sweden)

    Esbert, Rosa M.ª

    1991-03-01

    Full Text Available The different aspects related to the deterioration and conservation of stone, used as a construction material, are reviewed in this article. The petrographical characteristics and physical properties which control the durability of stone material are stated. The importance of the voids and the properties more directly linked to the up-taking and transfer of humidity through the stone are pointed out. Regarding to the deterioration processes, the role of water, soluble salts and atmospheric pollutants upon the different alteration mechanisms of the building stones is emphasized. Finally, the steps related to the stone conservation, and the methods and products more currently employed to that aim are revised.

    Se compendian los distintos aspectos relacionados con el deterioro y la conservación de la piedra utilizada como material de edificación. Se revisan las características petrográficas y propiedades físicas que controlan la durabilidad de los materiales pétreos, resaltando la importancia de los espacios vacíos y de aquellas propiedades más directamente relacionadas con la captación y transferencia de humedad por el interior de la piedra. En cuanto a los procesos de deterioro se destaca el papel del agua, de las sales solubles y de los contaminantes atmosféricos en los diversos mecanismos de alteración desarrollados en la piedra de edificación. Finalmente se plantean las diversas fases relacionadas con la conservación de la piedra, y se revisan los métodos y productos más empleados en la actualidad para tal fin.

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

    International Nuclear Information System (INIS)

    Kikuchi, Akira; Kanazawa, Hiroyuki; Togashi, Yoshihiro; Matumoto, Seiichiro; Nishino, Yasuharu; Ohwada, Isao; Nakata, Masahito; Amano, Hidetoshi; Mitamura, Hisayoshi

    1994-08-01

    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)

  5. Durable diamond-like carbon templates for UV nanoimprint lithography

    International Nuclear Information System (INIS)

    Tao, L; Ramachandran, S; Nelson, C T; Overzet, L J; Goeckner, M; Lee, G; Hu, W; Lin, M; Willson, C G; Wu, W

    2008-01-01

    The interaction between resist and template during the separation process after nanoimprint lithography (NIL) can cause the formation of defects and damage to the templates and resist patterns. To alleviate these problems, fluorinated self-assembled monolayers (F-SAMs, i.e. tridecafluoro-1,1,2,2,tetrahydrooctyl trichlorosilane or FDTS) have been employed as template release coatings. However, we find that the FDTS coating undergoes irreversible degradation after only 10 cycles of UV nanoimprint processes with SU-8 resist. The degradation includes a 28% reduction in surface F atoms and significant increases in the surface roughness. In this paper, diamond-like carbon (DLC) films were investigated as an alternative material not only for coating but also for direct fabrication of nanoimprint templates. DLC films deposited on quartz templates in a plasma enhanced chemical vapor deposition system are shown to have better chemical and physical stability than FDTS. After the same 10 cycles of UV nanoimprints, the surface composition as well as the roughness of DLC films were found to be unchanged. The adhesion energy between the DLC surface and SU-8 is found to be smaller than that of FDTS despite the slightly higher total surface energy of DLC. DLC templates with 40 nm features were fabricated using e-beam lithography followed by Cr lift-off and reactive ion etching. UV nanoimprinting using the directly patterned DLC templates in SU-8 resist demonstrates good pattern transfer fidelity and easy template-resist separation. These results indicate that DLC is a promising material for fabricating durable templates for UV nanoimprint lithography

  6. Durability of polymer/metal interfaces under cyclic loading

    Science.gov (United States)

    Du, Tianbao

    Fatigue crack growth along metal/epoxy interface was examined in an aqueous environment and under mixed-mode conditions. A stress corrosion cracking mechanism was identified in this process. The fatigue crack growth rate in an aqueous environment was increased by several orders of magnitude and the fatigue threshold decreased by a factor of 10. The loss of adhesion in the aqueous environment was induced by the hydration of the surface oxide which resulted in a hydroxide with poor adhesion to the substrate metal. Self-assembled monolayer of long chain alkyl phosphonic acid and amino phosphonic acid were synthesized to enhance the adhesion and improve the durability of Al/epoxy interfacial bonding system. The same approach was taken to promote adhesion between copper and epoxy, where a two-component coupling system of 11-mercapto-1-undercanol and 3-aminopropyltriethoxysilane provided the most significant improvement in the copper/epoxy adhesion. The mixed-mode was applied by a piezoelectric actuator. Subcritical crack growth was observed along the epoxy/aluminum interface and the growth rate was found to depend on the magnitude of the applied electric field. Kinetics of the crack growth was correlated with the piezoelectric driving force. The resulting crack growth behavior was compared with the results from the conventional mechanical testing technique. Large differences were found between these two methods. Using this newly developed technique, effects of loading mode and frequency were studied. The fatigue resistance was found to increase with the mode II component and was expressed as a function of the KII/K I ratio. A strong frequency effect was observed for the subcritical crack growth along the Al/Epoxy interface, their fatigue resistance increased with the testing frequency.

  7. Assessment of the Durability of Cementitious Materials in Repository Environment

    International Nuclear Information System (INIS)

    Vicente, R.; Marumo, J.T.; Miyamoto, H.; Isiki, V.L.K.; Ferreira, E.G.

    2013-01-01

    The Radioactive Waste Management Laboratory of the Energy and Nuclear Research Institute is developing the concept of a borehole repository for disused sealed radioactive sources drilled in a deep granite batholite. In this concept, the annular space between the well steel casing and the geological formation is backfilled with cement paste. The hardened cement paste functions as an additional barrier against the escape of radionuclides from the repository and their migration to the environment. It also functions as an obstacle to the flow of groundwater between different layers of the geological setting crossed by the borehole. The long term behavior of hydrated cement compounds is yet incompletely known and therefore more research is needed to increase the confidence on the performance of the material under the repository conditions as required. For the repository to achieve the required performance, the cement paste must be durable. However, in a deep repository, the cementitious materials is exposed to the deleterious action of high temperatures and pressures, the radiation field created by the radioactive sources and aggressive ion species that may be present in groundwater. Furthermore, it is necessary to consider that the cement paste is unstable in the long term because its microstructure and mineralogy change with time as the cement gel components recrystallize and react chemically with materials of the repository environment. In principle, the lifetime of this material could be determined based on the study of its long-term behavior, which, in turn, could be estimated from the extrapolation of short-term results, by accelerating, under controlled laboratory conditions, the composition changes and the loss of mechanical strength and cohesion induced by any detrimental component of the repository environment. Loss of mechanical strength, dimensional variations, changes in chemical-mineralogical composition, and leaching of hydrate compounds are all possible

  8. Biological durability of wood in relation to end-use - Part 1. Towards a European standard for laboratory testing of the biological durability of wood

    NARCIS (Netherlands)

    Acker, Van J.; Stevens, M.; Carey, J.; Sierra-Alvarez, R.; Militz, H.; Bayon, Le I.; Kleist, G.; Peek, R.D.

    2003-01-01

    The determination of biological durability of wood is an issue requiring sufficient reliability regarding end-use related prediction of performance. Five test institutes joined efforts to check standard test methods and to improve methodology and data interpretation for assessment of natural

  9. A comparative study of self-consolidating concretes incorporating high-volume natural pozzolan or high-volume fly ash

    KAUST Repository

    Celik, Kemal

    2014-09-01

    The purpose of this study is to compare the effects of Portland cement replacement on the strength and durability of self-consolidating concretes (SSC). The two replacement materials used are high-volume natural pozzolan (HVNP), a Saudi Arabian aluminum-silica rich basaltic glass and high-volume Class-F fly ash (HVFAF), from Jim Bridger Power Plant, Wyoming, US. As an extension of the study, limestone filler (LF) is also used to replace Portland cement, alongside HVNP or HVFAF, forming ternary blends. Along with compressive strength tests, non-steady state chloride migration and gas permeability tests were performed, as durability indicators, on SCC specimens. The results were compared to two reference concretes; 100% ordinary Portland cement (OPC) and 85% OPC - 15% LF by mass. The HVNP and HVFAF concrete mixes showed strength and durability results comparable to those of the reference concretes; identifying that both can effectively be used to produce low-cost and environmental friendly SCC. © 2013 Elsevier Ltd. All rights reserved.

  10. A comparative study of self-consolidating concretes incorporating high-volume natural pozzolan or high-volume fly ash

    KAUST Repository

    Celik, Kemal; Meral, Cagla; Mancio, Mauricio; Mehta, P. Kumar; Monteiro, Paulo J.M.

    2014-01-01

    The purpose of this study is to compare the effects of Portland cement replacement on the strength and durability of self-consolidating concretes (SSC). The two replacement materials used are high-volume natural pozzolan (HVNP), a Saudi Arabian aluminum-silica rich basaltic glass and high-volume Class-F fly ash (HVFAF), from Jim Bridger Power Plant, Wyoming, US. As an extension of the study, limestone filler (LF) is also used to replace Portland cement, alongside HVNP or HVFAF, forming ternary blends. Along with compressive strength tests, non-steady state chloride migration and gas permeability tests were performed, as durability indicators, on SCC specimens. The results were compared to two reference concretes; 100% ordinary Portland cement (OPC) and 85% OPC - 15% LF by mass. The HVNP and HVFAF concrete mixes showed strength and durability results comparable to those of the reference concretes; identifying that both can effectively be used to produce low-cost and environmental friendly SCC. © 2013 Elsevier Ltd. All rights reserved.

  11. 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)

  12. 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

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

    KAUST Repository

    Laveille, Paco; Guillois, Kevin; Tuel, Alain; Petit, Corine; Basset, Jean-Marie; Caps, Valerie

    2016-01-01

    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.

  14. 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.

  15. 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

  16. Performance Evaluation and Durability Studies of Adhesive Bonds

    Science.gov (United States)

    Ranade, Shantanu Rajendra

    In this thesis, four test approaches were developed to characterize the adhesion performance and durability of adhesive bonds for specific applications in areas spanning from structural adhesive joints to popular confectionaries such as chewing gum. In the first chapter, a double cantilever beam (DCB) specimen geometry is proposed for combinatorial fracture studies of structural adhesive bonds. This specimen geometry enabled the characterization of fracture energy vs. bondline thickness trends through fewer tests than those required during a conventional "one at a time" characterization approach, potentially offering a significant reduction in characterization times. The second chapter investigates the adhesive fracture resistance and crack path selection in adhesive joints containing patterns of discreet localized weak interfaces created using physical vapor deposition of copper. In a DCB specimen tested under mode-I conditions, fracture energy within the patterned regions scaled according to a simple rule of mixture, while reverse R-curve and R-curve type trends were observed in the regions surrounding weak interface patterns. Under mixed mode conditions such that bonding surface with patterns is subjected to axial tension, fracture energy did not show R-curve type trends while it was observed that a crack could be made to avoid exceptionally weak interfaces when loaded such that bonding surface with defects is subjected to axial compression. In the third chapter, an adaptation of the probe tack test is proposed to characterize the adhesion behavior of gum cuds. This test method allowed the introduction of substrates with well-defined surface energies and topologies to study their effects on gum cud adhesion. This approach and reported insights could potentially be useful in developing chewing gum formulations that facilitate easy removal of improperly discarded gum cuds from adhering surfaces. In the fourth chapter we highlight a procedure to obtain insights

  17. Quantitative Resistance to Plant Pathogens in Pyramiding Strategies for Durable Crop Protection

    Directory of Open Access Journals (Sweden)

    Marie-Laure Pilet-Nayel

    2017-10-01

    Full Text Available Quantitative resistance has gained interest in plant breeding for pathogen control in low-input cropping systems. Although quantitative resistance frequently has only a partial effect and is difficult to select, it is considered more durable than major resistance (R genes. With the exponential development of molecular markers over the past 20 years, resistance QTL have been more accurately detected and better integrated into breeding strategies for resistant varieties with increased potential for durability. This review summarizes current knowledge on the genetic inheritance, molecular basis, and durability of quantitative resistance. Based on this knowledge, we discuss how strategies that combine major R genes and QTL in crops can maintain the effectiveness of plant resistance to pathogens. Combining resistance QTL with complementary modes of action appears to be an interesting strategy for breeding effective and potentially durable resistance. Combining quantitative resistance with major R genes has proven to be a valuable approach for extending the effectiveness of major genes. In the plant genomics era, improved tools and methods are becoming available to better integrate quantitative resistance into breeding strategies. Nevertheless, optimal combinations of resistance loci will still have to be identified to preserve resistance effectiveness over time for durable crop protection.

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

    International Nuclear Information System (INIS)

    Koontz, S.L.; Jacobs, S.; Le, J.

    1993-03-01

    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

  19. Bio-inspired polymeric patterns with enhanced wear durability for microsystem applications

    International Nuclear Information System (INIS)

    Singh, R. Arvind; Siyuan, L.; Satyanarayana, N.; Kustandi, T.S.; Sinha, Sujeet K.

    2011-01-01

    At micro/nano-scale, friction force dominates at the interface between bodies moving in relative motion and severely affects their smooth operation. This effect limits the performance of microsystem devices such as micro-electro-mechanical systems (MEMS). In addition, friction force also leads to material removal or wear and thereby reduces the durability i.e. the useful operating life of the devices. In this work, we fabricated bio-inspired polymeric patterns for tribological applications. Inspired by the surface features on lotus leaves namely, the protuberances and wax, SU-8 polymeric films spin-coated on silicon wafers were topographically and chemically modified. For topographical modification, micro-scale patterns were fabricated using nanoimprint lithography and for chemical modification, the micro-patterns were coated with perfluoropolyether nanolubricant. Tribological investigation of the bio-inspired patterns revealed that the friction coefficients reduced significantly and the wear durability increased by several orders. In order to enhance the wear durability much further, the micro-patterns were exposed to argon/oxygen plasma and were subsequently coated with the perfluoropolyether nanolubricant. Bio-inspired patterns with enhanced wear durability, such as the ones investigated in the current work, have potential tribological applications in MEMS/Bio-MEMS actuator-based devices. Highlights: →Bio-inspired polymeric patterns for tribological applications in microsystems. →Novel surface modification for the patterns to enhance tribological properties. →Patterns show low friction properties and extremely high wear durability.

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

    International Nuclear Information System (INIS)

    Holt, E.

    2008-01-01

    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.)

  1. Durability of glasses from the Hg-doped Integrated DWPF Melter System (IDMS) campaign

    International Nuclear Information System (INIS)

    Jantzen, C.M.

    1992-01-01

    The Integrated DWPF Melter System (IDMS) for the vitrification of high-level radioactive wastes is designed and constructed to be a 1/9th scale prototype of the full scale Defense Waste Processing Facility (DWPF) melter. The IDMS facility is the first engineering scale melter system capable of processing mercury, and flowsheet levels of halides and noble metals. In order to determine the effects of mercury on the feed preparation process, the off-gas chemistry, glass melting behavior, and glass durability, a three-run mercury (Hg) campaign was conducted. The glasses produced during the Hg campaign were composed of Batch 1 sludge, simulated precipitate hydrolysis aqueous product (PHA) from the Precipitate Hydrolysis Experimental Facility (PHEF), and Frit 202. The glasses were produced using the DWPF process/product models for glass durability, viscosity, and liquidus. The durability model indicated that the glasses would all be more durable than the glass qualified in the DWPF Environmental Assessment (EA). The glass quality was verified by performing the Product Consistency Test (PCT) which was designed for glass durability testing in the DWPF

  2. Durable superhydrophobic paper enabled by surface sizing of starch-based composite films

    Science.gov (United States)

    Chen, Gang; Zhu, Penghui; Kuang, Yudi; Liu, Yu; Lin, Donghan; Peng, Congxing; Wen, Zhicheng; Fang, Zhiqiang

    2017-07-01

    Superhydrophobic paper with remarkable durability is of considerable interest for its practical applications. In this study, a scalable, inexpensive, and universal surface sizing technique was implemented to prepare superhydrophobic paper with enhanced durability. A thin layer of starch-based composite, acting as a bio-binder, was first coated onto the paper surface by a sophisticated manufacturing technique called surface sizing, immediately followed by a spray coating of hexamethyl disilazane treated silica nanoparticles (HMDS-SiNPs) dispersed in ethanol on the surface of the wet starch-coated sheet, and the dual layers dried at the same time. Consequently, durable superhydrophobic paper with bi-layer structure was obtained after air drying. The as-prepared superhydrophobic paper not only exhibited a self-cleaning behavior, but also presented an enhanced durability against scratching, bending/deformation, as well as moisture. The universal surface sizing of starch-based composites may pave the way for the up-scaled and cost-effective production of durable superhydrophobic paper.

  3. Investigation of the Durability of a Diaphragm for a Total Artificial Heart.

    Science.gov (United States)

    Gräf, Felix; Rossbroich, Ralf; Finocchiaro, Thomas; Steinseifer, Ulrich

    2016-10-01

    One of the most critical components regarding the durability of the ReinHeart total artificial heart (TAH) is its biocompatible diaphragm, which separates the drive unit from the ventricles. Hence, a durability tester was designed to investigate its required 5-year lifetime. The aim of this study was to prove the validity of accelerated testing of the polyurethane diaphragm. The durability tester allows simultaneous testing of 12 diaphragms and mimics physiological conditions. To accelerate the time of testing, it operates with an increased speed at a frequency of 8 Hz. To prove the correctness of this acceleration, a servo-hydraulic testing machine was used to study the effect of different frequencies and their corresponding loads. Thereby the viscoelastic behavior of the polyurethane was investigated. Additionally, high-speed video measurements were performed. The force against frequency and the high-speed video measurements showed constant behavior. In the range of 1-10 Hz, the maximum resulting forces varied by 3%, and the diaphragm movement was identical. Frequencies below 10 Hz allow a valid statement of the diaphragm's mechanical durability. Viscoelasticity of the polyurethane in the considered frequency-range is negligible. The accelerated durability test is applicable to polyurethane diaphragms, and the results are applicable to TAH use. The reliability of the diaphragm for a lifetime of 5 years was found to be 80% with a confidence of 62%. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  4. Production and remediation of low sludge simulated Purex waste glasses, 2: Effects of sludge oxide additions on glass durability

    International Nuclear Information System (INIS)

    Ramsey, W.G.

    1993-01-01

    Glass produced during the Purex 4 campaigns of the Integrated DWPF Melter System (IDMS) and the 774 Research Melter contained a lower fraction of sludge components than targeted by the Product Composition Control System (PCCS). Purex 4 glass was more durable than the benchmark (EA) glass, but was less durable than most other simulated SRS high-level waste glasses. Further, the measured durability of Purex 4 glass was not as well correlated with the durability predicted from the DWPF process control algorithm, probably because the algorithm was developed to predict the durability of SRS high-level waste glasses with higher sludge content than Purex 4. A melter run, designated Purex 4 Remediation, was performed using the 774 Research Melter to determine if the initial PCCS target composition determined for Purex 4 would produce acceptable glass whose durability could be accurately modeled by the DWPF glass durability algorithm. Reagent grade oxides and carbonates were added to Purex 4 melter feed stock to simulate a higher sludge loading. Each canister of glass produced was sampled and the glass durability was determined by the Product Consistency Test method. This document details the durability data and subsequent analysis

  5. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Chemical durability of soda-lime-aluminosilicate glass for radioactive waste vitrification

    International Nuclear Information System (INIS)

    Eppler, F.H.; Yim, M.S.

    1998-01-01

    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 Al 2 O 3 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

  7. Durability Properties of Self Compacting Concrete containing Fly ash, Lime powder and Metakaolin

    Directory of Open Access Journals (Sweden)

    Rizwan Ahmad Khan

    2016-01-01

    Full Text Available This paper investigates the durability properties of Self-compacting concrete (SCC, with different amounts of fly ash (FA, lime powder (LP and metakaolin (MK. A total of 6 mixes were prepared that have a constant water-binder ratio (w/b of 0.41 and superplasticizer dosage of 1% by weight of cement. In addition to compressive strength, the durability properties of SCC mixes were determined by means of Initial surface absorption test (ISAT and Capillary suction test. The test results indicated that the durability properties of the mixes appeared to be very dependent on the type and amount of the mineral admixture used; the mixes containing MK were found to have considerably higher permeability resistance. Good co-relation between strength and absorption were achieved.

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

    International Nuclear Information System (INIS)

    Bibler, N.E.; Tosten, M.H.; Beam, D.C.

    1989-01-01

    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 10 10 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

  9. 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.

  10. Highly Durable Platinum Single-Atom Alloy Catalyst for Electrochemical Reactions

    DEFF Research Database (Denmark)

    Kim, Jiwhan; Roh, Chi-Woo; Sahoo, Suman Kalyan

    2018-01-01

    Single atomic Pt catalyst can offer efficient utilization of the expensive platinum and provide unique selectivity because it lacks ensemble sites. However, designing such a catalyst with high Pt loading and good durability is very challenging. Here, single atomic Pt catalyst supported on antimony...... functional theory calculations show that replacing Sb sites with Pt atoms in the bulk phase or at the surface of SbSn or ATO is energetically favorable. The Pt1/ATO shows superior activity and durability for formic acid oxidation reaction, compared to a commercial Pt/C catalyst. The single atomic Pt...... structure is retained even after a harsh durability test, which is performed by repeating cyclic voltammetry in the range of 0.05–1.4 V for 1800 cycles. A full cell is fabricated for direct formic acid fuel cell using the Pt1/ATO as an anode catalyst, and an order of magnitude higher cell power is obtained...

  11. Carbon nanocages: a new support material for Pt catalyst with remarkably high durability.

    Science.gov (United States)

    Wang, Xiao Xia; Tan, Zhe Hua; Zeng, Min; Wang, Jian Nong

    2014-03-24

    Low durability is the major challenge hindering the large-scale implementation of proton exchange membrane fuel cell (PEMFC) technology, and corrosion of carbon support materials of current catalysts is the main cause. Here, we describe the finding of remarkably high durability with the use of a novel support material. This material is based on hollow carbon nanocages developed with a high degree of graphitization and concurrent nitrogen doping for oxidation resistance enhancement, uniform deposition of fine Pt particles, and strong Pt-support interaction. Accelerated degradation testing shows that such designed catalyst possesses a superior electrochemical activity and long-term stability for both hydrogen oxidation and oxygen reduction relative to industry benchmarks of current catalysts. Further testing under conditions of practical fuel cell operation reveals almost no degradation over long-term cycling. Such a catalyst of high activity, particularly, high durability, opens the door for the next-generation PEMFC for "real world" application.

  12. Studies of The Durability of Belt Conveyor Idlers with Working Loads Taken into Account

    Science.gov (United States)

    Król, Robert

    2017-12-01

    The results of laboratory and operational studies conducted in the Machinery Systems Division of Wroclaw University of Technology in recent years have became the basis for selecting proper belt conveyor roller designs optimized for specific strength and operational criteria. The usefulness of the results for assessing the energy intensity of idlers, estimating their durability and determining modernization policies has been confirmed. Methods of estimating the durability of carrying idlers on the basis of the identified output stream distributions are presented. Results of studies carried out using an analytical method and a laboratory method are reported. It has been shown that the operational durability of a roller is determined by its design, the roller set parameters (the spacing and the angle of bevel) and the operating conditions having a bearing on the irregularity of the transported output stream.

  13. Study on the durability of concrete using granulated blast furnace slag as fine aggregate

    Science.gov (United States)

    Shi, Dongsheng; Liu, Qiang; Xue, Xinxin; He, Peiyuan

    2018-03-01

    In order to assessing the durability of concrete using granulated blastfurnace slag (GBS) as fine aggregate and compare it with natural river sand concrete, three different size of specimen were produced by using the same mix proportion with 3 different water cement ratios and 3 replacement ratios, and using it to measure the three aspects on the durability of concrete including freeze-thaw performance, dry-shrinkage performance and anti-chloride-permeability performance. In this paper. The test results show that using GBS as fine aggregate can slightly improve anti-chloride-permeability performance and dry-shrinkage performance of concrete in the condition of low water cement ratio, on the other hand, using GBS or natural river sand as fine aggregate has almost similar durability of concrete.

  14. THE STUDY ON THE DURABILITY OF SUBMERGED STRUCTURE DISPLACEMENT DUE TO CONCRETE FAILURE

    Directory of Open Access Journals (Sweden)

    M. Mohd

    2016-09-01

    Full Text Available Concrete structures that exposed to marine environments are subjected to multiple deterioration mechanisms. An overview of the existing technology for submerged concrete, pressure resistant, concrete structures which related such as cracks, debonds, and delamination are discussed. Basic knowledge related to drowning durability such as submerged concrete structures in the maritime environment are the durability of a concrete and the ability to resist to weathering, chemical attack, abrasion or other deterioration processes. The measuring techniques and instrumentation for geometrical monitoring of submerged structural displacements have traditionally been categorized into two groups according to the two main groups, namely as geodetic surveying and geotechnical structural measurements of local displacements. This paper aims to study the durability of submerged concrete displacement and harmful effects of submerged concrete structures.

  15. Facile Fabrication of Durable Copper-Based Superhydrophobic Surfaces via Electrodeposition.

    Science.gov (United States)

    Jain, R; Pitchumani, R

    2018-03-13

    Superhydrophobic surfaces have myriad industrial applications, yet their practical utilization has been limited by their poor mechanical durability and longevity. We present a low-cost, facile process to develop superhydrophobic copper-based coatings via an electrodeposition route, that addresses this limitation. Through electrodeposition, a stable, multiscale, cauliflower shaped fractal morphology was obtained and upon modification by stearic acid, the prepared coatings show extreme water repellency with contact angle of 162 ± 2° and roll-off angle of about 3°. Systematic studies are presented on coatings fabricated under different processing conditions to demonstrate good durability, mechanical and underwater stability, corrosion resistance, and self-cleaning effect. The study also presents an approach for rejuvenation of slippery superhydrophobic nature (roll-off angle <10°) on the surfaces after long-term water immersion. The presented process can be scaled to larger, durable coatings with controllable wettability for diverse applications.

  16. Durability of reinforced concrete beams strengthened with fiber reinforced polymers under varying environmental conditions

    International Nuclear Information System (INIS)

    El-Sadani, R.A.M.G

    2008-01-01

    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.

  17. Assessing the representativeness of durability tests for wood pellets by DEM Simulation - Comparing conditions in a durability test with transfer chutes

    Science.gov (United States)

    Mahajan, Aditya; Dafnomilis, Ioannis; Hancock, Victoria; Lodewijks, Gabriel; Schott, Dingena

    2017-06-01

    Dust generation when handling wood pellets is related to the durability of the product, in other words the wear rate of particles subject to forces. During transport, storage and handling wood pellets undergo different forces when interacting with different pieces of equipment. This paper assesses the representativeness of the tumbling can test in relation to transfer chutes, by comparing forces acting on wood pellets in durability tests and in transfer chutes using DEM. The study also incorporates effects such as shape and size variations. The results showed that the tumbling can test underestimates compressive and tangential forces. Since the tested material is subject to milder conditions than in reality, it can be concluded that this test is not representative for the conditions in the supply chain of wood pellets.

  18. Influence of ceria on the thermally durability of Pt/Rh automotive catalyst

    International Nuclear Information System (INIS)

    Muraki, H.; Zhang, G.

    1998-01-01

    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

  19. The influence of the curing conditions of concrete on durability after freeze-thaw accelerated testing

    Directory of Open Access Journals (Sweden)

    Al-Assadi, G.

    2015-12-01

    Full Text Available This work relates the curing conditions of concrete with the damage caused by rapid freeze-thaw cycles (ASTM C 666. The “potential” durability of concrete after testing is also studied. In countries with a continental climate, the curing of concrete in summer is performed under high-temperature and low-humidity conditions, and during the winter the concrete undergoes freezing and thawing. This paper shows the experimental results of the behaviour of concrete specimens cured under climatic summer conditions and then subjected to freeze-thaw cycles. Curing of the specimens includes conditions of good and bad practice in relation to wetting and protection of the concrete. Mechanical properties, cement hydration, volume and pore sizes, oxygen permeability, chloride diffusion and water penetration under pressure tests of the concrete are assessed. These tests were performed before and after the application of the freeze-thaw cycles. Statistical analysis of the correlation among variables is also included.Este trabajo relaciona las condiciones de curado del hormigón con los daños causados por ciclos hielo-deshielo (ASTM C 666. Estudia la durabilidad “potencial” del hormigón dañado por este ensayo. En países con clima continental, el curado del hormigón en verano se realiza con alta temperatura y baja humedad, y durante el invierno sufre condiciones de hielo-deshielo. Se presentan los resultados experimentales de probetas de hormigón curadas bajo condiciones climáticas del verano y luego sometidas a ciclos hielo-deshielo. El curado de las probetas incluye condiciones de buenas y malas prácticas en relación con el curado del hormigón. Se miden las propiedades mecánicas, grado de hidratación, volumen de poros y distribución de tamaños, permeabilidad al oxígeno, penetración de agua bajo presión y coeficiente de difusión de cloruros antes y después de la aplicación de los ciclos de hielo-deshielo. Se incluye un estudio estad

  20. Weathering durability of commercial polymeric coatings tested by positron annihilation spectroscopy

    International Nuclear Information System (INIS)

    Chen, H.; Peng, Q.; Huang, Y.Y.; Zhang, R.; Li, Y.; Zhang, J.; Wu, Y.C.; Richardson, J.R.; Sandreczki, T.C.; Jean, Y.C.

    2003-01-01

    A series of commercial coatings were prepared according to the industrial specifications and were exposed to Florida natural weathering and controlled UVA irradiation. The Doppler broadening energy spectra (DBES) of positron annihilation were measured as a function of incident positron energy at different periods of weathering. A significant decrease in the S parameter was observed and it was used as an indicator to test coating durability in micro-scale. Application to weathering durability of commercial polymeric coatings under natural weathering and controlled UVA irradiation is investigated by using the S parameter from the DBES

  1. Characterization and durability testing of a glass-bonded ceramic waste form

    International Nuclear Information System (INIS)

    Johnson, S. G.

    1998-01-01

    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

  2. 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

    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...... and after exposure to different thermal conditions is very important. In this paper, an experimental study concerning the influence of temperature and moisture in cyclic conditions on the durability of polymer concrete based on an unsaturated polyester resin is described and the results are presented...

  3. The influence of fly ash as substitute of cement in the durability of concrete

    OpenAIRE

    Molina Bas, Omar I.; Moragues Terrades, Amparo; Gálvez Ruíz, Jaime; Guerrero Bustos, Ana

    2008-01-01

    Limitation of transport capacity through the concrete is one of the key points in the improvement of the material’s durability. The use of fly ash as an admixture to concrete is widely extended; a general consensus has been established due to the pore size reduction produced by the ashes. Nevertheless, the importance of the micro-structural and composition changes in mechanical and durable properties is not well defined. In the present study the use of fly ash has been considered as substitut...

  4. Fused Microknot Optical Resonators in Folded Photonic Tapers for in-Liquid Durable Sensing

    Directory of Open Access Journals (Sweden)

    Alexandra Logvinova

    2018-04-01

    Full Text Available Optical microknot fibers (OMFs serve as localized devices, where photonic resonances (PRs enable self-interfering elements sensitive to their environment. However, typical fragility and drifting of the knot severely limit the performance and durability of microknots as sensors in aqueous settings. Herein we present the fabrication, electrical fusing, preparation, and persistent detection of volatile liquids in multiple wetting–dewetting cycles of volatile compounds and quantify the persistent phase shifts with a simple model relating to the ambient liquid, enabling durable in-liquid sensing employing OMF PRs.

  5. Composition models for the viscosity and chemical durability of West Valley related nuclear waste glasses

    International Nuclear Information System (INIS)

    Feng, X.; Saad, E.E.; Freeborn, W.P.; Macedo, P.B.; Pegg, I.L.; Sassoon, R.E.; Barkatt, A.; Finger, S.M.

    1988-01-01

    There are two important criteria that must be satisfied by a nuclear waste glass durability and processability. The chemical composition of the glass must be such that it does not dissolve or erode appreciably faster than the decay of the radioactive materials embedded in it. The second criterion, processability, means that the glass must melt with ease, must be easily pourable, and must not crystallize appreciably. This paper summarizes the development of simple models for predicting the durability and viscosity of nuclear waste glasses from their composition

  6. 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.

  7. Durability aspects of high-performance concretes for a waste repository. Appendix 3: Canada

    International Nuclear Information System (INIS)

    Philipose, K.E.

    2001-01-01

    The IRUS facility for the disposal of low level radioactive waste at the Chalk River Nuclear Laboratories in Ontario, Canada relies on the durability of concrete for the required 500 years of service life. A research programme based on laboratory testing to design a durable concrete and assess its long-term behaviour was initiated in 1988. This appendix discusses the methodology to assess the long-term behaviour of concrete, and some initial observations. Longevity predictions for concrete formulations based on diffusion testing are also presented

  8. Estimation of metallic structure durability for a known law of stress variation

    Science.gov (United States)

    Mironov, V. I.; Lukashuk, O. A.; Ogorelkov, D. A.

    2017-12-01

    Overload of machines working in transient operational modes leads to such stresses in their bearing metallic structures that considerably exceed the endurance limit. The estimation of fatigue damages based on linear summation offers a more accurate prediction in terms of machine durability. The paper presents an alternative approach to the estimation of the factors of the cyclic degradation of a material. Free damped vibrations of the bridge girder of an overhead crane, which follow a known logarithmical decrement, are studied. It is shown that taking into account cyclic degradation substantially decreases the durability estimated for a product.

  9. Influence of the leaching mode on the durability of a glass for fission product containment

    International Nuclear Information System (INIS)

    Nogues, J.L.; Terki, A.

    1984-06-01

    The chemical durability of a glass containing wastes from light water reactor (LWR) has been studied with three different lixiviation modes: ''static'' leach test, ''soxhlet'' test and ''continuous flow'' test. After a description of these tests, the leaching mode influence on the glass durability is reported as obtained from weight loss measurements, analyses of the leaching solutions and surface analyses of the samples. Finally, the corrosion mechanisms of this type of glass are approached and a phenomenological explanation of attack from an aqueous solution is proposed [fr

  10. Durability and degradation of HT9 based alloy waste forms with variable Ni and Cr content

    Energy Technology Data Exchange (ETDEWEB)

    Olson, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-12-31

    Short-term electrochemical and long-term hybrid electrochemical corrosion tests were performed on alloy waste forms in reference aqueous solutions that bound postulated repository conditions. The alloy waste forms investigated represent candidate formulations that can be produced with advanced electrochemical treatment of used nuclear fuel. The studies helped to better understand the alloy waste form durability with differing concentrations of nickel and chromium, species that can be added to alloy waste forms to potentially increase their durability and decrease radionuclide release into the environment.

  11. Durability Issues of High Temperature Proton Exchange Membrane Fuel Cells Based on Acid Doped Polybenzimidazole Membranes

    DEFF Research Database (Denmark)

    . As a critical concern, issues of long term durability of PBI based fuel cells are addressed in this talk, including oxidative degradation of the polymer, mechanical failures of the membrane, acid leaching out, corrosion of carbon support and sintering of catalysts particles. Excellent polymer durability has...... or ionically cross-linking and structure modification With load, thermal or startup-shutdown cycling, the performance loss was found to be much bigger, about 300 µV per cycle or 40 µV per operating hour, due to the increased acid loss and catalyst support corrosion, particularly under open circuit voltage...... operation. Further efforts are outlined to the future work....

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. - Highlights: • Realistic simulations in the cabinet of one-year exposure to environmental conditions • Influence of the lime type on the durability of hemp–lime renders

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

    Energy Technology Data Exchange (ETDEWEB)

    Arizzi, Anna, E-mail: anna.arizzi@ouce.ox.ac.uk [School of Geography and the Environment, University of Oxford, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY (United Kingdom); Viles, Heather [School of Geography and the Environment, University of Oxford, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY (United Kingdom); Martín-Sanchez, Inés [Departamento de Microbiología, Universidad de Granada, Avda. Fuentenueva s/n, 18002 Granada (Spain); Cultrone, Giuseppe [Departamento de Mineralogía y Petrología, Universidad de Granada, Avda. Fuentenueva s/n, 18002 Granada (Spain)

    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. - Highlights: • Realistic simulations in the cabinet of one-year exposure to environmental conditions • Influence of the lime type on the durability of hemp–lime renders

  14. Crosslinked polybenzimidazoles containing branching structure as membrane materials with excellent cell performance and durability for fuel cell applications

    Science.gov (United States)

    Hu, Meishao; Ni, Jiangpeng; Zhang, Boping; Neelakandan, Sivasubramaniyan; Wang, Lei

    2018-06-01

    Crosslinking is an effective method to improve the properties of high temperature proton exchange membranes based on polybenzimidazole. However, the compact structure of crosslinked polybenzimidazole hinders the phosphoric acid absorption of the membranes, resulting in a relatively poor fuel cell performance. Recently, we find that branched polymers can absorb more phosphoric acid with a larger free volume, but suffer from deteriorated mechanical strength. In this work, a new method is proposed to obtain excellent over-all properties of high temperature proton exchange membranes. A series of crosslinked polybenzimidazoles containing branching structure as membrane materials are successfully prepared for the first time. Compared with conventional crosslinked membranes, these crosslinked polybenzimidazole membranes containing branching structure exhibit a higher phosphoric acid doping level and proton conductivity, improved durability, lower swelling rate and comparable mechanical strength. In particular, the fuel cell base on the crosslinked and branched membrane with a 10% ratio of crosslinker in non-humidified hydrogen/air at 160 °C achieves a power density of 404 mW cm-2. The results indicate that the combination of crosslinking and branching is an effective approach to improve the properties of polybenzimidazole membrane materials.

  15. INFLUENCE OF KENAF AND POLYPROPYLENE FIBRES ON MECHANICAL AND DURABILITY PROPERTIES OF FIBRE REINFORCED LIGHTWEIGHT FOAMED CONCRETE

    Directory of Open Access Journals (Sweden)

    H. AWANG

    2015-04-01

    Full Text Available This paper investigates the mechanical and durability properties of lightweight foamed concrete (LFC with the inclusion of kenaf and polypropylene fibres. A density of 1000kg/m3 foamed concrete was used for all the tested specimens. The ratio of cement, sand and water used was 1:1.5:0.45. Polypropylene and kenaf fibres were used as additives at 0.25% and 0.4% by volume of the total mix. A 30% cement replacement by fly ash was used with each type of additive. All the experiments were set up in accordance with International standard methods of testing. Scanning electron microscopy (SEM analysis is included to have a better view of the concrete behavior with fibre inclusions. In reference to the analysis and discussion, the types of fibre used were proven to have a lesser contribution towards compressive strength or might even have reduced the result. However, the integration of fly ash enhanced the compressive strength. In addition, a higher percentage of fiber inclusions had been recorded to have a positive contribution towards flexural, tensile spiltting and shrinkage properties of LFC.

  16. The identification and treatment of poor durability Karoo dolerite base course aggregate – evidence from case studies

    CSIR Research Space (South Africa)

    Leyland, RC

    2016-03-01

    Full Text Available that the poor performance of the case study materials was likely due to the poor durability of the materials, manifesting as a reduction in resistance to abrasion and attrition. The identification of the observed poor durability could not have been performed...

  17. 76 FR 35950 - Agency Information Collection Activity (Living Will and Durable Power of Attorney for Health Care...

    Science.gov (United States)

    2011-06-20

    ... (Living Will and Durable Power of Attorney for Health Care) Under OMB Review AGENCY: Department of... INFORMATION Title: Living Will and Durable Power of Attorney for Health Care, VA Form 10-0137. OMB Control... about his or her medical treat and to record specific instructions about their treatment preferences in...

  18. Durability and plasticity of a material under different trajectories cycle loading in dependence on the loading prehistory

    International Nuclear Information System (INIS)

    Mozharovskij, N.S.; Bobyr', N.I.

    1979-01-01

    Results of investigations into the durability and plasticity of a material under combined proportional cyclic loading over different trajectories depending upon the values of intensity of preliminary plastic deformation obtained by different loading methods are presented. The effect of loading prehistory type on material plastic properties and its durability are shown

  19. Durability and plasticity of a material under different trajectories cycle loading in dependence on the loading prehistory

    Energy Technology Data Exchange (ETDEWEB)

    Mozharovskii, N S; Bobyr, N I [Kievskij Politekhnicheskij Inst. (Ukrainian SSR)

    1979-12-01

    Results of investigations into the durability and plasticity of a material under combined proportional cyclic loading over different trajectories depending upon the values of intensity of preliminary plastic deformation obtained by different loading methods are presented. The effect of loading prehistory type on material plastic properties and its durability are shown.

  20. FORECASTING OF DURABILITY OF ASPHALT PAVEMENT ON THE BASIS OF LEVELS OF THEIR VIBRATION LOADING

    Directory of Open Access Journals (Sweden)

    V. A. Osinovskaya

    2015-01-01

    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.

  1. Durability analysis of a reinforced concrete member using probabilistic SBRA method

    Czech Academy of Sciences Publication Activity Database

    Pustka, D.; Marek, Pavel

    2007-01-01

    Roč. 2007, č. 7 (2007), s. 91-94 ISSN 1505-8425 R&D Projects: GA ČR(CZ) GA103/07/0557 Institutional research plan: CEZ:AV0Z20710524 Keywords : Reliability * Durability * SBRA method Subject RIV: JM - Building Engineering

  2. Durability and safety of concrete structures in the nuclear context. The case of the containment vessel

    Energy Technology Data Exchange (ETDEWEB)

    Torrenti, J.M. [Universite Paris Est, LCPC (France); Nahas, G. [IRSN/DSR (France)

    2011-07-01

    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)

  3. Durability of certain configurations for providing skid resistance on concrete pavements.

    Science.gov (United States)

    1974-01-01

    The main objective of this study was to establish the factors that influence the durability of the surface configurations that are used or can be used to provide high and long lasting skid resistance for portland cement concrete pavements. In the dev...

  4. Design of concrete structures for durability ; Example : Chloride penetration in the lining of a bored tunnel

    NARCIS (Netherlands)

    Siemes, T.; Polder, R.; Vries, H. de

    1998-01-01

    To design concrete structures for durability, all relevant performances that the structure has to fulfill and that can be influenced by degradations have to be defined. The probability that a given performance must be delivered within a design service life should also be considered. One of the

  5. 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.

  6. Durability Indicators Comparison for SCC and CC in Tropical Coastal Environments.

    Science.gov (United States)

    Calado, Carlos; Camões, Aires; Monteiro, Eliana; Helene, Paulo; Barkokébas, Béda

    2015-03-27

    Self-compacting concrete (SCC) demands more studies of durability at higher temperatures when subjected to more aggressive environments in comparison to the conventional vibrated concrete (CC). This work aims at presenting results of durability indicators of SCC and CC, having the same water/binder relations and constituents. The applied methodologies were electrical resistivity, diffusion of chloride ions and accelerated carbonation experiments, among others, such as microstructure study, scanning electron microscope and microtomography experiments. The tests were performed in a research laboratory and at a construction site of the Pernambuco Arena. The obtained results shows that the SCC presents an average electrical resistivity 11.4% higher than CC; the average chloride ions diffusion was 63.3% of the CC; the average accelerated carbonation penetration was 45.8% of the CC; and the average open porosity was 55.6% of the CC. As the results demonstrated, the SCC can be more durable than CC, which contributes to elucidate the aspects related to its durability and consequent prolonged life cycle.

  7. Construction of Polarized Carbon-Nickel Catalytic Surfaces for Potent, Durable, and Economic Hydrogen Evolution Reactions.

    Science.gov (United States)

    Zhou, Min; Weng, Qunhong; Popov, Zakhar I; Yang, Yijun; Antipina, Liubov Yu; Sorokin, Pavel B; Wang, Xi; Bando, Yoshio; Golberg, Dmitri

    2018-05-22

    Electrocatalytic hydrogen evolution reaction (HER) in alkaline solution is hindered by its sluggish kinetics toward water dissociation. Nickel-based catalysts, as low-cost and effective candidates, show great potentials to replace platinum (Pt)-based materials in the alkaline media. The main challenge regarding this type of catalysts is their relatively poor durability. In this work, we conceive and construct a charge-polarized carbon layer derived from carbon quantum dots (CQDs) on Ni 3 N nanostructure (Ni 3 N@CQDs) surfaces, which simultaneously exhibit durable and enhanced catalytic activity. The Ni 3 N@CQDs shows an overpotential of 69 mV at a current density of 10 mA cm -2 in a 1 M KOH aqueous solution, lower than that of Pt electrode (116 mV) at the same conditions. Density functional theory (DFT) simulations reveal that Ni 3 N and interfacial oxygen polarize charge distributions between originally equal C-C bonds in CQDs. The partially negatively charged C sites become effective catalytic centers for the key water dissociation step via the formation of new C-H bond (Volmer step) and thus boost the HER activity. Furthermore, the coated carbon is also found to protect interior Ni 3 N from oxidization/hydroxylation and therefore guarantees its durability. This work provides a practical design of robust and durable HER electrocatalysts based on nonprecious metals.

  8. Relationship between enamel bond fatigue durability and surface free-energy characteristics with universal adhesives.

    Science.gov (United States)

    Nagura, Yuko; Tsujimoto, Akimasa; Barkmeier, Wayne W; Watanabe, Hidehiko; Johnson, William W; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

    2018-04-01

    The relationship between enamel bond fatigue durability and surface free-energy characteristics with universal adhesives was investigated. The initial shear bond strengths and shear fatigue strengths of five universal adhesives to enamel were determined with and without phosphoric acid pre-etching. The surface free-energy characteristics of adhesive-treated enamel with and without pre-etching were also determined. The initial shear bond strength and shear fatigue strength of universal adhesive to pre-etched enamel were higher than those to ground enamel. The initial shear bond strength and shear fatigue strength of universal adhesive to pre-etched enamel were material dependent, unlike those to ground enamel. The surface free-energy of the solid (γ S ) and the hydrogen-bonding force (γSh) of universal adhesive-treated enamel were different depending on the adhesive, regardless of the presence or absence of pre-etching. The bond fatigue durability of universal adhesives was higher to pre-etched enamel than to ground enamel. In addition, the bond fatigue durability to pre-etched enamel was material dependent, unlike that to ground enamel. The surface free-energy characteristics of universal adhesive-treated enamel were influenced by the adhesive type, regardless of the presence or absence of pre-etching. The surface free-energy characteristics of universal adhesive-treated enamel were related to the results of the bond fatigue durability. © 2018 Eur J Oral Sci.

  9. [Aftercare for durability and profitability of single-unit and multi-unit fixed dental prostheses

    NARCIS (Netherlands)

    Baat, C. de; Loveren, C. van; Maarel-Wierink, C.D. van der; Witter, D.J.; Creugers, N.H.J.

    2013-01-01

    An important aim ofa treatment with single-unit and multi-unit fixed dental prostheses is a durable and profitable treatment outcome. That requires aftercare, too. First, the frequency of routine oral examinations should be assessed, using an individual risk profile. The objectives of the routine

  10. 40 CFR 86.1825-08 - Durability demonstration procedures for refueling emissions.

    Science.gov (United States)

    2010-07-01

    ..., statistical analyses, additional data, or other information which is relevant to the decision. The... Durability demonstration procedures for refueling emissions. This section applies to 2008 and later model...-duty rules as allowed under the provisions of § 86.1801-01(c)(1) which are subject to refueling loss...

  11. 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.

  12. 75 FR 26196 - Publication of OIG Updated Special Fraud Alert on Telemarketing by Durable Medical Equipment...

    Science.gov (United States)

    2010-05-11

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Office of Inspector General Publication of OIG Updated Special Fraud Alert on Telemarketing by Durable Medical Equipment Suppliers AGENCY: Office of Inspector...) 205-0007. SUPPLEMENTARY INFORMATION: In our publication of the OIG Updated Special Fraud Alert on...

  13. Durability Indicators Comparison for SCC and CC in Tropical Coastal Environments

    Directory of Open Access Journals (Sweden)

    Carlos Calado

    2015-03-01

    Full Text Available Self-compacting concrete (SCC demands more studies of durability at higher temperatures when subjected to more aggressive environments in comparison to the conventional vibrated concrete (CC. This work aims at presenting results of durability indicators of SCC and CC, having the same water/binder relations and constituents. The applied methodologies were electrical resistivity, diffusion of chloride ions and accelerated carbonation experiments, among others, such as microstructure study, scanning electron microscope and microtomography experiments. The tests were performed in a research laboratory and at a construction site of the Pernambuco Arena. The obtained results shows that the SCC presents an average electrical resistivity 11.4% higher than CC; the average chloride ions diffusion was 63.3% of the CC; the average accelerated carbonation penetration was 45.8% of the CC; and the average open porosity was 55.6% of the CC. As the results demonstrated, the SCC can be more durable than CC, which contributes to elucidate the aspects related to its durability and consequent prolonged life cycle.

  14. A Framework of Retailer-Manufacturer Cooperation and Coopetition: Consumer Durable Goods Retailers’ Case Studies

    Directory of Open Access Journals (Sweden)

    Marzanna Katarzyna Witek-Hajduk

    2017-03-01

    Full Text Available Objective: The purpose of this paper is to develop a framework of cooperation and coopetition between retailers and key manufacturers from a perspective of retailers offering consumer durables. Research Design & Methods: In order to answer the research questions semi-structured, in-depth and face-to-face interviews with managers of six SMEs or large retailers operating in Poland and offering consumer durables were carried out. Findings: The empirical studies confirm both cooperation and coopetition between retailers and manufacturers – suppliers of consumer durables depending on, among others, the category of consumer goods and the balance of power between retailers and manufacturers. The scope of cooperation is not too wide, and concerns only some of the value chain processes indicated in the literature. Implications & Recommendations: Conducted studies are exploratory and need to be deepen with the use of quantitative research that will help determine the impact of the balance of power between manufacturers and retailers and the strength of retailer-manufacturer relations on the range / areas and financial and non-financial performance of this cooperation. Contribution & Value Added: The originality of this work lies in studying some aspects of retailers’ relations with their key suppliers operating in consumer durables market.

  15. Soy adhesives that can form durable bonds for plywood, laminated wood flooring, and particleboard

    Science.gov (United States)

    Charles R. Frihart; Michael J. Birkeland; Anthony J. Allen; James M. Wescott

    2010-01-01

    Synthetic adhesives, including urea-formaldehyde (UF) and phenol-formaldehyde (PF), have generally replaced biobased adhesives over the past 70 years because of their durability, low cost, and ease of use. However, in the past few years, concern about formaldehyde emissions, cost, and interest in biobased materials have renewed interest in soy adhesives. The use of soy...

  16. Gas chromatography-mass spectrometry (GC-MS) analysis of extractives of naturally durable wood

    Science.gov (United States)

    G.T. Kirker; A.B. Blodgett; S.T. Lebow; C.A. Clausen

    2011-01-01

    A preliminary study to evaluate naturally durable wood species in an above ground field trial using Gas Chromatography-Mass Spectrometry (GC-MS) detected differences in fatty acid extractives between species and within the same species over time. Fatty acids were extracted with chloroform: methanol mixture then methylated with sodium methoxide and fractionated using...

  17. Durable SOC stacks for production of hydrogen and synthesis gas by high temperature electrolysis

    DEFF Research Database (Denmark)

    Ebbesen, Sune Dalgaard; Høgh, Jens Valdemar Thorvald; Nielsen, Karsten Agersted

    2011-01-01

    . The degradation of the electrolysis cells was found to be influenced by the adsorption of impurities from the applied inlet gases, whereas the application of chromium containing interconnect plates and glass sealings do not seem to influence the durability when operated at 850 °C. Cleaning the inlet gases...

  18. Concilier des performances pour une agriculture durable - L'agriculture biologique comme prototype.

    OpenAIRE

    Sautereau, Natacha; Penvern, Servane; Petitgenet, Morgane; Fauriel, Joël; Bellon, Stéphane

    2011-01-01

    L'agriculture biologique est de plus en plus reconnue comme prototype d’agriculture durable car elle combine de multiples performances. Toutefois des tensions apparaissent entre certaines de ces performances. Une équipe de l’unité Écodéveloppement d’Avignon explore ces tensions en l'arboriculture fruitière.

  19. 42 CFR 410.38 - Durable medical equipment: Scope and conditions.

    Science.gov (United States)

    2010-10-01

    ... or purchase of durable medical equipment, including iron lungs, oxygen tents, hospital beds, and wheelchairs, if the equipment is used in the patient's home or in an institution that is used as a home. (b... vehicle whose steering is operated by an electronic device or a joystick to control direction and turning...

  20. 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.

  1. Radiometric emanation method for the assessment of the durability of building materials towards aggressive media

    International Nuclear Information System (INIS)

    Balek, V.; Beckman, I.N.

    1991-01-01

    A new express method has been suggested for testing durability of building materials in contact with aggressive liquids and gases. The method is based on the measurement of radon released from samples studied, continuously during the interaction of the sample with the aggressive medium. The samples are previously labeled by the source of radon atoms, i.e. thorium Th-228 and radium Ra-224 are incorporated in the samples to be tested. Due to high sensitivity of the method the first stages of the interaction between the cement stone (concrete) sample and aggressive liquid or gas can be followed. The express information about the relative durability of the building materials was obtained. This method was also advantageously used for the investigation of corrosion early stage of marble (calcium carbonate) by sulphur dioxide (in the concentrations of 500-3,000 ppm). The most advantageous application of the method is for rapid assessment of the relative durability of building materials, e.g. the information about the relative durability of the samples studied was obtained within several minutes, resp. hours, whereas by means of traditional chemical methods it needs several weeks or months

  2. Revision Cycles for Economics Textbooks: An Application of the Theory of Durable Goods Monopoly

    Science.gov (United States)

    Li, Xin

    2011-01-01

    In this dissertation, I study economics textbook markets as an example of durable goods monopoly. Textbooks are protected by copyrights, and from a student's point of view, different textbooks are not good substitutes because students wish to use the textbook adopted by their instructors. Therefore sellers have market power. Textbooks can be…

  3. 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

  4. THE EFFECT OF HEAT TREATMENT ON THE DURABILITY OF BAMBOO Gigantochloa scortechinii

    Directory of Open Access Journals (Sweden)

    Norashikin Kamarudin

    2012-07-01

    Full Text Available Bamboo signifies as one of the fastest growing plants and it can be used for various products. In tropical countries such as Indonesia and Malaysia, bamboo is abundantly available at reasonable prices, therefore it is used for numerous purposes. However, as lignocellulosic material, bamboo is susceptible to fungal and insect attacks. Heat treatment is an option to improve bamboo's durability. The objective of this study was to improve the durability of bamboo using hot oil palm treatment. A Malaysian grown bamboo species, Buluh Semantan (Gigantochloa scortechinii, as a study material was soaked in hot oil palm for various temperatures and soaking time, before being inoculated with the basidiomycete Coriolus versicolor in an agar block test. The results demonstrated that the longer the heating time, the more improved the durability of bamboo. Altering the temperature in the palm oil treatment produced varying results. Bamboo blocks that heated in hot oil palm at 100°C for 60 minutes shows considerably less weight eduction that indicates less fungal attack. Overall, the higher the temperature, the better the durability of bamboo. Please indicates what the meaning of heat treatment in this experiment, it is not clear.

  5. Polymeric carbon nitride nanomesh as an efficient and durable metal-free catalyst for oxidative desulfurization.

    Science.gov (United States)

    Shen, Lijuan; Lei, Ganchang; Fang, Yuanxing; Cao, Yanning; Wang, Xinchen; Jiang, Lilong

    2018-03-06

    We report the first use of polymeric carbon nitride (CN) for the catalytic selective oxidation of H 2 S. The as-prepared CN with unique ultrathin "nanomeshes" structure exhibits excellent H 2 S conversion and high S selectivity. In particular, the CN nanomesh also displays better durability in the desulfurization reaction than traditional catalysts, such as carbon- and iron-based materials.

  6. Liquidus temperature and chemical durability of selected glasses to immobilize rare earth oxides waste

    Energy Technology Data Exchange (ETDEWEB)

    Mohd Fadzil, Syazwani, E-mail: mfsyazwani86@postech.ac.kr [Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, 790784 Pohang, Gyeongbuk (Korea, Republic of); School of Applied Physics, Faculty of Science and Technology, The National University of Malaysia, 43650 Bandar Baru Bangi, Selangor (Malaysia); Hrma, Pavel [Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, 790784 Pohang, Gyeongbuk (Korea, Republic of); Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA (United States); Schweiger, Michael J.; Riley, Brian J. [Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA (United States)

    2015-10-15

    Pyroprocessing is are processing method for managing and reusing used nuclear fuel (UNF) by dissolving it in an electrorefiner with a molten alkali or alkaline earth chloride salt mixture while avoiding wet reprocessing. Pyroprocessing UNF with a LiCl–KCl eutectic salt releases the fission products from the fuel and generates a variety of metallic and salt-based species, including rare earth (RE) chlorides. If the RE-chlorides are converted to oxides, borosilicate glass is a prime candidate for their immobilization because of its durability and ability to dissolve almost any RE waste component into the glass matrix at high loadings. Crystallization that occurs in waste glasses as the waste loading increases may complicate glass processing and affect the product quality. This work compares three types of borosilicate glasses in terms of liquidus temperature (T{sub L}): the International Simple Glass designed by the International Working Group, sodium borosilicate glass developed by Korea Hydro and Nuclear Power, and the lanthanide aluminoborosilicate (LABS) glass established in the United States. The LABS glass allows the highest waste loadings (over 50 mass% RE{sub 2}O{sub 3}) while possessing an acceptable chemical durability. - Highlights: • We investigated crystallization in borosilicate glasses containing rare earth oxides. • New crystallinity and durability data are shown for glasses proposed in the literature. • Both liquidus temperature and chemical durability increased as the waste loading increased.

  7. 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

  8. 40 CFR 86.1823-01 - Durability demonstration procedures for exhaust emissions.

    Science.gov (United States)

    2010-07-01

    ...) Discussion of the manufacturer's in-use verification procedures including testing performed, vehicle... performed should also be documented in the manufacturer's submission. The in-use verification program shall...), the Alternate Service Accumulation Durability Program described in § 86.094-13(e) or the Standard Self...

  9. Prior use of durable medical equipment as a risk adjuster for health-based capitation

    NARCIS (Netherlands)

    R.C. van Kleef (Richard); R.C.J.A. van Vliet (René)

    2010-01-01

    textabstractThis paper examines a new risk adjuster for capitation payments to Dutch health plans, based on the prior use of durable medical equipment (DME). The essence is to classify users of DME in a previous year into clinically homogeneous classes and to apply the resulting classification as a

  10. Modeling of asphalt durability and self-healing with discrete particles method

    NARCIS (Netherlands)

    Magnanimo, Vanessa; ter Huerne, Henderikus L.; Luding, Stefan; Beuving, E.; Dewez, P.; Malkoc, G.; Southern, M.

    2012-01-01

    Asphalt is an important road paving material. Besides an acceptable price, durability, surface conditions (like roughening and evenness), age-, weather- and traffic-induced failures and degradation are relevant aspects. In the professional road-engineering branch empirical models are used to

  11. Asphalt durability and self-healing modelling with discrete particles approach

    NARCIS (Netherlands)

    Magnanimo, V.; ter Huerne, H.L.; Luding, S.; Scarpas, A.; Kringos, N.; Al-Qadi, I.; Loizos, A.

    2012-01-01

    Asphalt is an important road paving material, where besides an acceptable price, durability, surface conditions (like roughening and evenness), age-, weather- and traffic-induced failures and degradation are relevant aspects. In the professional road engineering branch empirical models are used to

  12. Informing the improvement of forest products durability using small angle neutron scattering

    Science.gov (United States)

    Nayomi Plaza Rodriguez; Sai Venkatesh Pingali; Shuo Qian; William T. Heller; Joseph E. Jakes

    2016-01-01

    A better understanding of how wood nanostructure swells with moisture is needed to accelerate the development of forest products with enhanced moisture durability. Despite its suitability to study nanostructures, small angle neutron scattering (SANS) remains an underutilized tool in forest products research. Nanoscale moisture-induced structural changes in intact and...

  13. A Test Method for Monitoring Modulus Changes during Durability Tests on Building Joint Sealants

    Science.gov (United States)

    Christopher C. White; Donald L. Hunston; Kar Tean Tan; Gregory T. Schueneman

    2012-01-01

    The durability of building joint sealants is generally assessed using a descriptive methodology involving visual inspection of exposed specimens for defects. It is widely known that this methodology has inherent limitations, including that the results are qualitative. A new test method is proposed that provides more fundamental and quantitative information about...

  14. L'évolution du développement durable | CRDI - Centre de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    28 janv. 2011 ... Profil du domaine de programme Environnement et gestion des ressources naturelles (EGRN) du CRDILe « développement durable » est un terme largement utilisé dont la signification diffère selon qui l'emploie. Notre avenir à tous, rapport de la Commission Brundtland paru en 1987, définit le ...

  15. Durability of adhesive bonds to uranium alloys, tungsten, tantalum, and thorium

    International Nuclear Information System (INIS)

    Childress, F.G.

    1975-01-01

    Long-term durability of epoxy bonds to alloys of uranium (U-Nb and Mulberry), nickel-plated uranium, thorium, tungsten, tantalum, tantalum--10 percent tungsten, and aluminum was evaluated. Significant strengths remain after ten years of aging; however, there is some evidence of bond deterioration with uranium alloys and thorium stored in ambient laboratory air

  16. Life cycle and economic efficiency analysis phase II : durable pavement markings.

    Science.gov (United States)

    2011-04-01

    This report details the Phase II analysis of the life cycle and economic efficiency of inlaid tape : and thermoplastic. Waterborne paint was included as a non-durable for comparison purposes : only. In order to find the most economical product for sp...

  17. Effect of Hydrostatic Pressure on Defect Structure and Durability of Ultrafine-Grained Aluminum

    Czech Academy of Sciences Publication Activity Database

    Betekhtin, V.I.; Kadomtsev, A. G.; Sklenička, Václav; Narykova, M. V.

    2011-01-01

    Roč. 37, č. 10 (2011), s. 977-979 ISSN 1063-7850 Institutional research plan: CEZ:AV0Z20410507 Keywords : defect structure * ultrafine-grained aluminium * durability Subject RIV: JG - Metallurgy Impact factor: 0.565, year: 2011

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

    International Nuclear Information System (INIS)

    Hrma, P.; Piepel, G.F.; Schweiger, M.J.; Smith, D.E.

    1992-04-01

    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 Al 2 O 3 , moderately increased by addition of ZrO 2 and SiO 2 , and decreased by addition of Li 2 O, Na 2 O, B 2 O 3 , and MgO. Addition of Fe 2 O 3 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

  19. Distribution Patterns of Polyphosphate Metabolism Pathway and Its Relationships With Bacterial Durability and Virulence

    Directory of Open Access Journals (Sweden)

    Liang Wang

    2018-04-01

    Full Text Available Inorganic polyphosphate (polyP is a linear polymer of orthophosphate residues. It is reported to be present in all life forms. Experimental studies showed that polyP plays important roles in bacterial durability and virulence. Here we investigated the relationships of polyP with bacterial durability and virulence theoretically. Bacterial lifestyle, environmental persistence, virulence factors (VFs, and species evolution are all included in the analysis. The presence of seven genes involved in polyP metabolism (ppk1, ppk2, pap, surE, gppA, ppnK, and ppgK and 2595 core VFs were verified in 944 bacterial reference proteomes for distribution patterns via HMMER. Proteome size and VFs were compared in terms of gain and loss of polyP pathway. Literature mining and phylogenetic analysis were recruited to support the study. Our analyzes revealed that the presence of polyP metabolism is positively correlated with bacterial proteome size and the number of virulence genes. A potential relationship of polyP in bacterial lifestyle and environmental durability is suggested. Evolutionary analysis shows that polyP genes are randomly lost along the phylogenetic tree. In sum, based on our theoretical analysis, we confirmed that bacteria with polyP metabolism are associated with high environmental durability and more VFs.

  20. Campus Involvement as a Predictor for Durable Leadership Development in Conjunction with Leadership Program Participation

    Science.gov (United States)

    Rosch, David M.; Stephens, Clinton M.

    2017-01-01

    Postsecondary educators have long been faced with the challenge of developing the leadership capacity of their students. This research investigated the following research question: To what degree do formal opportunities for involvement predict durable growth in leadership capacity in students who participate in a formal leadership development…

  1. Research on Grooved Concrete Pavement Based on the Durability of Its Anti-Skid Performance

    Directory of Open Access Journals (Sweden)

    Mulian Zheng

    2018-05-01

    Full Text Available The objectives of the present study are to investigate the anti-skid performance of concrete pavement and to attempt to enhance its durability by two different methods: using a longitudinally-transversely grooved (LT form, and using a self-developed composite curing agent containing paraffin and Na2SiO3 as the main ingredients. The friction coefficient (μ was measured by self-developed equipment to evaluate the anti-skid performance of samples with three different groove forms (LT, longitudinally grooved (L, and transversely grooved (T. Abrasion tests were then carried out to evaluate the durability of the anti-skid performance. The results indicated that anti-skid performance of LT samples was approximately 46.2% greater than that of T samples, but its durability was not as significant as that of T samples. However, the resistance to abrasion could be improved by using the aforementioned curing agent. Comparisons were carried out between samples sprayed the curing agent and control samples without any curing agent under standard conditions. It was found that the application of the curing agent increased the anti-skid durability of concrete by 35.4%~47.8%, proving it to be a useful and promising technique.

  2. Durability assessment of concrete sheet piling in the 'De Betuweroute' railway line

    NARCIS (Netherlands)

    Peelen, W.H.A.; Polder, R.B.

    2004-01-01

    Assessment of the durability of prestressed concrete sheet piles under the interference of CP gas pipeline system current, established that due to their low magnitude, these currents do not compromise the required 100-year service life of the structures. The sophisticated numerical modelling tools

  3. The central role of wood biology in understanding the durability of wood-coating interactions

    Science.gov (United States)

    Alex C. Wiedenhoeft

    2007-01-01

    To design effectively for durability, one must actively and honestly assess the material properties and limitations of each of the components in the design system; wood or wood composite, and the coating. Inasmuch as wood coatings are manufactured to specified tolerances from known materials, we have control of that component of the system. Compared to manmade...

  4. Durability and safety of concrete structures in the nuclear context. The case of the containment vessel

    International Nuclear Information System (INIS)

    Torrenti, J.M.; Nahas, G.

    2011-01-01

    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)

  5. Durability of saw-cut joints in plain cement concrete pavements : [technical summary].

    Science.gov (United States)

    2011-01-01

    The main objective of this study was to evaluate factors influencing the durability of the joints in portland cement concrete pavement in the state of Indiana. : The scope of the research included the evaluation of the absorption of water in concrete...

  6. Influence of curing conditions on durability of alkali-resistant glass ...

    Indian Academy of Sciences (India)

    Glass fibres in concrete material often increase the flexural strength. However, these fibres when in contact with cement are altered by alkali reactions due to the presence of portlandite. This study presents the results of investigation to show the effect of curing conditions on the durability of alkali-resistant glass fibres in ...

  7. Durability of lightweight concrete : Phase II : wetting and drying tests, Phase III : freezing and thawing tests.

    Science.gov (United States)

    1966-12-01

    This report describes a laboratory research program on the durability of lightweight concrete. Two phases of a three phase study are covered by this report, while the remaining phase is still under study. The two phases being reported are Phase II - ...

  8. 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.

  9. Effect of stylolites on the durability of building stones : Two case studies

    NARCIS (Netherlands)

    Larbi, J.A.

    2003-01-01

    The mechanical properties and the durability of natural building stones are influenced to a large extent by inherent inhomogeneities. One of such inhomogeneities is a stylolite, particularly when it occuts in carbonate-rich rocks. Stylolites are irregular surfaces in which small tooth-like

  10. Effect of nanoclay on durability and mechanical properties of flax fabric reinforced geopolymer composites

    Directory of Open Access Journals (Sweden)

    H. Assaedi

    2017-03-01

    Full Text Available The main concern of using natural fibres as reinforcement in geopolymer composites is the durability of the fibres. Geopolymers are alkaline in nature because of the alkaline solution that is required for activating the geopolymer reaction. The alkalinity of the matrix, however, is the key reason of the degradation of natural fibres. The purpose of this study is to determine the effect of nanoclay (NC loading on the mechanical properties and durability of flax fabric (FF reinforced geopolymer composites. The durability of composites after 4 and 32 weeks at ambient temperature is presented. The microstructure of geopolymer matrices was investigated using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM. The results showed that the incorporation of NC has a positive impact on the physical properties, mechanical performance, and durability of FF reinforced geopolymer composites. The presence of NC has a positive impact through accelerating the geopolymerization, reducing the alkalinity of the system and increasing the geopolymer gel.

  11. Am/Cm target glass durability dependence on pH (U). Revision 1

    International Nuclear Information System (INIS)

    Daniel, W.E.; Best, D.R.

    1996-03-01

    At the Westinghouse Savannah River Company near Aiken, South Carolina, a process is being developed to safely vitrify all of the highly radioactive americium/curium (Am/Cm) material and a portion of the other fissile actinide materials stored on site. One goal of this campaign is to provide Oak Ridge National Laboratory with the excess Am/Cm so it can be recycled as opposed to simply disposing of it as waste. The vitrification will allow safe transportation of the Am/Cm to Oak Ridge as well as safe storage once it arrives. The Am/Cm Target glass being used in this project has been specifically designed to be extremely durable in aqueous environments while it can be selectively attacked by nitric acid to recover the valuable Am and Cm isotopes. Similar glass compositions could be used for storage and retrieval of other actinides on the WSRC site. Previous reports have presented the time, temperature, and compositional dependence of the Am/Cm glass durability. This paper will show results from a pH study on the Am/Cm Target glass durability. The data indicate that the Am/Cm Target Glass durability decreases as pH decreases from a neutral reading. These findings support the extraction of the valuable isotopes from the glass using nitric acid

  12. Durability of precast prestressed concrete piles in marine environment, part 2. Volume 2 : stainless steel prestressing strand and wire.

    Science.gov (United States)

    2012-06-01

    The overall purpose of this research was to determine methods which may be applied : economically to mitigate corrosion of reinforcement in precast prestressed concrete piles in : Georgias marine environments. The research was divided into two par...

  13. Tamper-indicating devices and safeguards seals evaluation test report. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Horton, P.R.V.; Waddoups, I.G.

    1995-08-01

    Volume I was based on a survey and an evaluation of seals that are used as tamper-indicating devices at DOE facilities. For that evaluation, currently available seals were physically and environmentally evaluated under two broad categories: handling durability and tamper resistance. Our study indicated that the environmental testing had no negative effects on the results of the mechanical tests. In Volume II, we evaluate some loop, fiber optic loop, and pressure-sensitive seals that are not used at DOE facilities. However, we continue to focus on qualities required by DOE: durability and tamper resistance. The seals are comparatively rated, and recommendations are made for using currently available seals and new tamper-indicating device technology.

  14. Tamper-indicating devices and safeguards seals evaluation test report. Volume 2

    International Nuclear Information System (INIS)

    Horton, P.R.V.; Waddoups, I.G.

    1995-08-01

    Volume I was based on a survey and an evaluation of seals that are used as tamper-indicating devices at DOE facilities. For that evaluation, currently available seals were physically and environmentally evaluated under two broad categories: handling durability and tamper resistance. Our study indicated that the environmental testing had no negative effects on the results of the mechanical tests. In Volume II, we evaluate some loop, fiber optic loop, and pressure-sensitive seals that are not used at DOE facilities. However, we continue to focus on qualities required by DOE: durability and tamper resistance. The seals are comparatively rated, and recommendations are made for using currently available seals and new tamper-indicating device technology

  15. Thermal Conductivity and Erosion Durability of Composite Two-Phase Air Plasma Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Schmitt, Michael P.; Rai, Amarendra K.; Zhu, Dongming; Dorfman, Mitchell R.; Wolfe, Douglas E.

    2015-01-01

    To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7 wt% yttria stabilized zirconia (7YSZ), approximately 1200 C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t' Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by approximately 13 and approximately 25%, respectively. The 40 wt% t' Low-k composite (40 wt% t' Low-k - 60 wt% cubic Low-k) showed a approximately 22% reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal in the composite coating. It was observed that a mere 20 wt% t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37%. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability.

  16. Concomitant Use of Immunomodulators Affects the Durability of Infliximab Therapy in Children With Crohn's Disease.

    Science.gov (United States)

    Grossi, Victoria; Lerer, Trudy; Griffiths, Anne; LeLeiko, Neal; Cabrera, Jose; Otley, Anthony; Rick, James; Mack, David; Bousvaros, Athos; Rosh, Joel; Grossman, Andrew; Saeed, Shehzaad; Kay, Marsha; Boyle, Brendan; Oliva-Hemker, Maria; Keljo, David; Pfefferkorn, Marian; Faubion, William; Kappelman, Michael D; Sudel, Boris; Markowitz, James; Hyams, Jeffrey S

    2015-10-01

    It is important to determine the effects of immunomodulators on the ability of children to remain on infliximab therapy for Crohn's disease (durability of therapy), given the potential benefits and risks of concomitant therapy-especially with thiopurines in male patients. We investigated how immunomodulatory treatment affects the durability of infliximab therapy. We collected data from the Pediatric Inflammatory Bowel Disease Collaborative Research Group Registry, from January 2002 through August 2014, on 502 children with Crohn's disease who participated in a prospective multicenter study. Data were collected from patients who received at least a 3-dose induction regimen of infliximab, and their concomitant use of immunomodulators: no thiopurine or methotrexate treatment, treatment for 6 months or less during infliximab therapy, or treatment for more than 6 months during infliximab therapy. The probabilities (± standard error) that children remained on infliximab therapy for 1 year, 3 years, and 5 years after the treatment began were 0.84 ± 0.02, 0.69 ± 0.03, and 0.60 ± 0.03, respectively. Age, sex, and disease extent or location did not affect the durability of infliximab therapy. Greater length of concomitant use of immunomodulators was associated with increased time of infliximab therapy. The probability that patients with more than 6 months of immunomodulator use remained on infliximab therapy for 5 years was 0.70 ± 0.04, compared with 0.48 ± 0.08 for patients who did not receive immunomodulators and 0.55 ± 0.06 for patients who received immunomodulators for 6 months or less (P immunomodulators for 6 months or more after starting infliximab, the overall durability of infliximab therapy was greater among patients receiving methotrexate than thiopurine (P immunomodulator for more than 6 months after starting infliximab therapy increases the chances that patients will remain on infliximab. In boys, methotrexate appears to increase the durability of

  17. Structure and Chemical Durability of Lead Crystal Glass.

    Science.gov (United States)

    Angeli, Frédéric; Jollivet, Patrick; Charpentier, Thibault; Fournier, Maxime; Gin, Stéphane

    2016-11-01

    Silicate glasses containing lead, also called lead crystal glasses, are commonly used as food product containers, in particular for alcoholic beverages. Lead's health hazards require major attention, which can first be investigated through the understanding of Pb release mechanisms in solution. The behavior of a commercial crystal glass containing 10.6 mol % of PbO (28.3 wt %) was studied in a reference solution of 4% acetic acid at 22, 40, and 70 °C at early and advanced stages of reaction. High-resolution solid-state 17 O and 29 Si NMR was used to probe the local structure of the pristine and, for the first time, of the altered lead crystal glass. Inserted into the vitreous structure between the network formers as Si-O-Pb bonds, Pb does not form Pb-O-Pb clusters which are expected to be more easily leached. A part of K is located near Pb, forming mixed Si-O-(Pb,K) near the nonbridging oxygens. Pb is always released into the solution following a diffusion-controlled dissolution over various periods of time, at a rate between 1 and 2 orders of magnitude lower than the alkalis (K and Na). The preferential release of alkalis is followed by an in situ repolymerization of the silicate network. Pb is only depleted in the outermost part of the alteration layer. In the remaining part, it stays mainly surrounded by Si in a stable structural configuration similar to that of the pristine glass. A simple model is proposed to estimate the Pb concentration as a function of glass surface, solution volume, temperature, and contact time.

  18. The Sit-and-Wait Hypothesis in Bacterial Pathogens: A Theoretical Study of Durability and Virulence

    Directory of Open Access Journals (Sweden)

    Liang Wang

    2017-11-01

    Full Text Available The intriguing sit-and-wait hypothesis predicts that bacterial durability in the external environment is positively correlated with their virulence. Since its first proposal in 1987, the hypothesis has been spurring debates in terms of its validity in the field of bacterial virulence. As a special case of the vector-borne transmission versus virulence tradeoff, where vector is now replaced by environmental longevity, there are only sporadic studies over the last three decades showing that environmental durability is possibly linked with virulence. However, no systematic study of these works is currently available and epidemiological analysis has not been updated for the sit-and-wait hypothesis since the publication of Walther and Ewald’s (2004 review. In this article, we put experimental evidence, epidemiological data and theoretical analysis together to support the sit-and-wait hypothesis. According to the epidemiological data in terms of gain and loss of virulence (+/- and durability (+/- phenotypes, we classify bacteria into four groups, which are: sit-and-wait pathogens (++, vector-borne pathogens (+-, obligate-intracellular bacteria (--, and free-living bacteria (-+. After that, we dive into the abundant bacterial proteomic data with the assistance of bioinformatics techniques in order to investigate the two factors at molecular level thanks to the fast development of high-throughput sequencing technology. Sequences of durability-related genes sourced from Gene Ontology and UniProt databases and virulence factors collected from Virulence Factor Database are used to search 20 corresponding bacterial proteomes in batch mode for homologous sequences via the HMMER software package. Statistical analysis only identified a modest, and not statistically significant correlation between mortality and survival time for eight non-vector-borne bacteria with sit-and-wait potentials. Meanwhile, through between-group comparisons, bacteria with higher

  19. Durability and inflammogenic impact of carbon nanotubes compared with asbestos fibres

    Directory of Open Access Journals (Sweden)

    Clark Steve

    2011-05-01

    Full Text Available Abstract Background It has been suggested that carbon nanotubes might conform to the fibre pathogenicity paradigm that explains the toxicities of asbestos and other fibres on a continuum based on length, aspect ratio and biopersistence. Some types of carbon nanotubes satisfy the first two aspects of the fibre paradigm but only recently has their biopersistence begun to be investigated. Biopersistence is complex and requires in vivo testing and analysis. However durability, the chemical mimicking of the process of fibre dissolution using in vitro treatment, is closely related to biopersistence and more readily determined. Here, we describe an experimental process to determine the durability of four types of carbon nanotubes in simulated biological fluid (Gambles solution, and their subsequent pathogenicity in vivo using a mouse model sensitive to inflammogenic effects of fibres. The in vitro and in vivo results were compared with well-characterised glass wool and asbestos fibre controls. Results After incubation for up to 24 weeks in Gambles solution, our control fibres were recovered at percentages consistent with their known in vitro durabilities and/or in vivo persistence, and three out of the four types of carbon nanotubes tested (single-walled (CNTSW and multi-walled (CNTTANG2, CNTSPIN showed no, or minimal, loss of mass or change in fibre length or morphology when examined by electron microscopy. However, the fourth type [multi-walled (CNTLONG1] lost 30% of its original mass within the first three weeks of incubation, after which there was no further loss. Electron microscopy of CNTLONG1 samples incubated for 10 weeks confirmed that the proportion of long fibres had decreased compared to samples briefly exposed to the Gambles solution. This loss of mass and fibre shortening was accompanied by a loss of pathogenicity when injected into the peritoneal cavities of C57Bl/6 mice compared to fibres incubated briefly. CNTSW did not elicit an

  20. Are Press Depictions of Affordable Care Act Beneficiaries Favorable to Policy Durability?

    Science.gov (United States)

    Chattopadhyay, Jacqueline

    2015-01-01

    If successfully implemented and enduring, the Affordable Care Act (ACA) stands to expand health insurance access in absolute terms, reduce inter-group disparities in that access, and reduce exposure to the financial vulnerabilities illness entails. Its durability--meaning both avoidance of outright retrenchment and fidelity to its policy aims--is thus of scholarly interest. Past literature suggests that social constructions of a policy's beneficiaries may impact durability. This paper first describes media portrayals of ACA beneficiaries with an eye toward answering three descriptive questions: (1) Do portrayals depict beneficiaries as economically heterogeneous? (2) Do portrayals focus attention on groups that have acquired new political relevance due to the ACA, such as young adults? (3) What themes that have served as messages about beneficiary "deservingness" in past social policy are most frequent in ACA beneficiary portrayals? The paper then assesses how the portrayal patterns that these questions uncover may work both for and against the ACA's durability, finding reasons for confidence as well as caution. Using manual and automated methods, this paper analyzes newspaper text from August 2013 through January 2014 to trace portrayals of two ACA "target populations" before and during the new law's first open-enrollment period: those newly eligible for Medicaid, and those eligible for subsidies to assist in the purchase of private health insurance under the ACA. This paper also studies newspaper text portrayals of two groups informally crafted by the ACA in this timeframe: those gaining health insurance and those losing it. The text data uncover the following answers to the three descriptive questions for the timeframe studied: (1) Portrayals may underplay beneficiaries' economic heterogeneity. (2) Portrayals pay little attention to young adults. (3) Portrayals emphasize themes of workforce participation, economic self-sufficiency, and insider status. Health

  1. Durability of reinforced adobe exposed to chloride ions

    Directory of Open Access Journals (Sweden)

    Giménez, A.

    2006-12-01

    Full Text Available One of the primary shortcomings of adobe, a dried mudblock stabilized with sisal hemp and cement widely used across all of Latin America, is its dimensional instability when exposed to water or aggressive environments. The present paper evaluates the electrochemical performance of reinforced adobe block after 1,000 days of exposure to a simulated marine environment. The specimens used were adobe blocks internally reinforced with 3/8-inch steel bars. The specimens were watered every two weeks: one group with potable water to simulate a natural urban environment and the other with a 3% sodium chloride solution to simulate a marine environment.Chloride penetration in powder extracted from the specimens was determined using the Mohr method. Electrochemical measurements included Gecor 6 electric potential(Eº and corrosion intensity (icorr readings. The final conclusion drawn from an analysis of the results was that in all cases the amount of free chlorides present sufficed to depassivate reinforcing steel and that the system component providing the most effective protection was the rough casting mortar. Consequently, this type of adobe mixes is not recommended for use in marine or industrial environments.La tierra-cemento-sisal es un material cuyo uso se encuentra muy difundido en toda Latinoamérica, entre sus principales limitaciones está la inestabilidad volumétrica ante el agua y ambientes agresivos. Por tal motivo, en este trabajo se evaluó el comportamiento electroquímico de bloques de tierra-cemento-sisal armado expuestos durante 1.000 días a un ambiente marino simulado. Las probetas utilizadas fueron bloques de tierra-cemento-sisal incorporándole internamente barras de acero de 3/8 de pulg. Las probetas se sometieron a un rociado quincenal: las de ambiente natural urbano con agua potable y las de ambiente marino simulado con una solución al 3% de cloruro de sodio. La penetración de cloruros se determinó extrayendo polvillo y

  2. Durability of ITO-MgF2 Films for Space-Inflatable Polymer Structures

    Science.gov (United States)

    Kerslake, Thomas W.; Waters, Deborah L.; Schieman, David A.; Hambourger, Paul D.

    2003-01-01

    This paper presents results from ITO-MgF2 film durability evaluations that included tape peel, fold, thermal cycle, and AO exposure testing. Polymer coupon preparation is described as well as ITO-MgF2 film deposition equipment, procedures and film characterization. Durability testing methods are also described. The pre- and post-test condition of the films is assessed visually, microscopically, and electrically. Results show that at 500 ITO - 9 vol% MgF2 film is suitable to protect polymer surfaces, such as those used in space-inflatable structures of the PowerSphere microsatellite concept, during a 1-year Earth orbiting mission. Future plans for ground-based and orbital testing of this film are also discussed.

  3. Fatigue Durability Analysis of Collecting Rapping System in Electrostatic Precipitators under Impact Loading

    Directory of Open Access Journals (Sweden)

    Ali Akbar Lotfi Neyestanak

    2014-01-01

    Full Text Available Due to the importance of collecting rapping system in electrostatic precipitators (ESP and controlling the relevant damage under impact loading, fatigue durability of this system is analyzed in the present study based on the numerical and experimental results considering fatigue damage growth and vibration acceleration in the collecting system because of the successive impact of rapping hammers. By microscopic examination of the fracture surface of rapping hammer, beach marks obviously show typical fatigue failure in the rapping hammer arm. In addition, the microscopic examination of the cross section of the collecting plates indicates the corrosion voids which cause crack and eventually fatigue failure. The finite element method is applied to determine both the stress and concentration positions of dynamic stress on the rapping system under impact loading. The paper results can be utilized in system optimization and new material selection for the system by evaluating rapping system durability.

  4. Durability and Strength of Sustainable Self-Consolidating Concrete Containing Fly Ash

    Science.gov (United States)

    Mohamed, O.; Hawat, W. Al

    2018-03-01

    In this paper, the durability and strength of self-consolidating concrete (SCC) is assessed through development and testing of six binary mixes at fixed water-to-binder (w/b) ratio of 0.36. In each of the six SCC mixes, a different percentage of cement is replaced with fly ash. The development of compressive strength for each of the mixes is assessed by testing samples after 3, 7, and 28 days of curing. Durability of each of the six SCC mixes is assessed by measuring the charge passed in Rapid Chloride Permeability (RCP) test. Charge passed was measured in samples cured for 1, 3, 7, 14, 28, and 40 days of curing. All mixes out-performed the control mix in terms of resistance to chloride penetration. Binary mix in which 20% of cement is replaced with fly ash exhibited 28-day strength slightly surpassing the control mix.

  5. Electrocatalysts and their Supporting Materials for Proton Exchange Membrane Fuel Cells: Activity and Durability Studies

    DEFF Research Database (Denmark)

    Permyakova, Anastasia Aleksandrovna

    of methanol electro-oxidation for ALD deposited Pt films on Si(100) and Pt-Si alloys on Si(100). ALD deposited Pt films on Si(100) were subsequently annealed at various temperatures to obtain Pt-Si alloy film on Si(100). Obtained alloys were subsequently characterised as potentially highly active methanol...... in oxygen reduction, carbon monoxide and methanol electro-oxidation reactions were explored. Employed catalysts were characterized electrochemically and physiochemically using techniques such as: cyclic voltammetry, rotating disk electrode technique, SEM, TEM, EDS, XPS, TGA/DTA, Raman, XRD, FTIR-IR among...... to long-term durability procedures. A significant part of the PhD study involved development of electrochemical instrumentation and techniques, such as: RDE and set-up, oxygen reduction, methanol and CO electrooxidation, long-term durability procedures, etc. The techniques employed by the author were self...

  6. Durable regenerable sorbent pellets for removal of hydrogen sulfide coal gas

    Science.gov (United States)

    Siriwardane, Ranjani V.

    1999-01-01

    Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are prepared in durable form, usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

  7. Durable regenerable sorbent pellets for removal of hydrogen sulfide from coal gas

    Science.gov (United States)

    Siriwardane, Ranjani V.

    1997-01-01

    Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are prepared in durable form usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

  8. FAA/NASA International Symposium on Advanced Structural Integrity Methods for Airframe Durability and Damage Tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Harris, C.E.

    1994-09-01

    International technical experts in durability and damage tolerance of metallic airframe structures were assembled to present and discuss recent research findings and the development of advanced design and analysis methods, structural concepts, and advanced materials. The symposium focused on the dissemination of new knowledge and the peer-review of progress on the development of advanced methodologies. Papers were presented on: structural concepts for enhanced durability, damage tolerance, and maintainability; new metallic alloys and processing technology; fatigue crack initiation and small crack effects; fatigue crack growth models; fracture mechanics failure, criteria for ductile materials; structural mechanics methodology for residual strength and life prediction; development of flight load spectra for design and testing; and advanced approaches to resist corrosion and environmentally assisted fatigue. Separate abstracts have been indexed for articles from this report.

  9. A high-spin and durable polyradical: poly(4-diphenylaminium-1,2-phenylenevinylene).

    Science.gov (United States)

    Murata, Hidenori; Takahashi, Masahiro; Namba, Kazuaki; Takahashi, Naoki; Nishide, Hiroyuki

    2004-02-06

    A purely organic, high-spin, and durable polyradical molecule was synthesized: It is based on the non-Kekulé- and non-disjoint design of a pi-conjugated poly(1,2-phenylenevinylene) backbone pendantly 4-substituted with multiple robust arylaminium radicals. 4-N,N-Bis(4-methoxy- and -tert-butylphenyl)amino-2-bromostyrene 5 were synthesized and polymerized with a palladium-phosphine catalyst to afford the head-to-tail-linked polyradical precursors (1). Oxidation of 1 with the nitrosonium ion solubilized with a crown ether gave the aminium polyradicals (1(+)()) which were durable (half-life > 1 month) at room temperature in air. A high-spin ground state with an average S = (4.5)/2 for 1a(+) was proved even at room temperature by magnetic susceptibility, magnetization, ESR, and NMR measurements.

  10. Reactive powder based concretes: Mechanical properties, durability and hybrid use with OPC

    International Nuclear Information System (INIS)

    Cwirzen, A.; Penttala, V.; Vornanen, C.

    2008-01-01

    The basic mechanical properties, frost durability and the bond strength with normal strength concretes of the ultra high strength (UHS) mortars and concretes were studied. The produced mixes had plastic or fluid-like consistency. The 28-day compressive strength varied between 170 and 202 MPa for the heat-treated specimens and between 130 and 150 MPa for the non-heat-treated specimens. The shrinkage values were two times higher for the UHS mortars in comparison with the UHS concretes. After the initial shrinkage, swelling was noticed in the UHS mortars. The lowest creep values were measured for the non-heat-treated UHS concretes. The frost-deicing salts durability of the UHS mortars and concretes appeared to be very good even despite the increased water uptake of the UHS concretes. The study of the hybrid concrete beams indicated the formation of low strength transition zone between the UHS mortar and normal strength concrete

  11. Durability of cracked fibre reinforced concrete exposed to freeze-thaw and deicing salt

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1998-01-01

    Durability studies are carried out by subjecting FRC-beams to combined mechanical and environmental load. Mechanical load is obtained by subjecting beams to 4-point bending until a predefined crack width is reached. Specimens sawn from the beams after unloading are exposed to freeze-thaw and deic......Durability studies are carried out by subjecting FRC-beams to combined mechanical and environmental load. Mechanical load is obtained by subjecting beams to 4-point bending until a predefined crack width is reached. Specimens sawn from the beams after unloading are exposed to freeze-thaw...... and deicing salt. The concrete has a water-powder ratio of 0.38 including both fly ash and silica fume. Both steel fibres (ZP, 0.4 vol%) and polypropylene fibres (PP, 1 vol%) are used as well as main reinforcement. The freeze-thaw test emphasizes the need for a critical evaluation of the mix design and mixing...

  12. Study on durability and reliability of strut type suspension noise based on experimental methods

    International Nuclear Information System (INIS)

    Kim, Gu Gyong; Kang, Sung Su; Lee, Yong Jun; Park, Soon Cheol; Jung, Won Wook

    2012-01-01

    When cars are released from the factory, strut noises are very small and therefore it is difficult to perceive them. As the use time and travel distance increase, however, strut noises get larger so as to cause users much uneasiness. The noises generated at the field include engine noises and flow noises and therefore it is difficult to clearly discern the noises generated from struts. This study developed a test method which can reproduce field strut noises in the lab. Using the newly developed noise evaluation test, this study analyzed the effects that insulator performance degradation and failure can have on car noises. The study also confirmed that the insulator durability test by the simple back-and-forth motion cannot completely reflect the state of the parts failure in the field. Based on this, the study also confirmed that field noises can be reproduced through a durability test that considers heat aging

  13. Application of microorganisms in concrete: a promising sustainable strategy to improve concrete durability.

    Science.gov (United States)

    Wang, Jianyun; Ersan, Yusuf Cagatay; Boon, Nico; De Belie, Nele

    2016-04-01

    The beneficial effect of microbially induced carbonate precipitation on building materials has been gradually disclosed in the last decade. After the first applications of on historical stones, promising results were obtained with the respect of improved durability. An extensive study then followed on the application of this environmentally friendly and compatible material on a currently widely used construction material, concrete. This review is focused on the discussion of the impact of the two main applications, bacterial surface treatment and bacteria based crack repair, on concrete durability. Special attention was paid to the choice of suitable bacteria and the metabolic pathway aiming at their functionality in concrete environment. Interactions between bacterial cells and cementitious matrix were also elaborated. Furthermore, recommendations to improve the effectiveness of bacterial treatment are provided. Limitations of current studies, updated applications and future application perspectives are shortly outlined.

  14. Investigation of durability of silica fume concretes in coastal structures within tidal zone

    International Nuclear Information System (INIS)

    Ganjian, E.; Sadeghi Pouya, H.

    2003-01-01

    In recent decade use of silica fume has been become greater in coastal concrete structures in the persona gulf, to increase durability of those establishments. In this research the durability of cement passers and concrete cubes with use of 7 and 10 percent of silica fume as a cement replacement have been investigated in three curing conditions (fresh water, coast of sea and simulation bonds) by measuring compressive strengths and capillary absorption. Silica fume specimens under wetting and drying condition showed more strength loss after 180 days compare to samples without silica fume or cured in the fresh water. In addition the greater silica fume amount in specimens cured within tidal zone and under wetting and drying simulation, the more water absorption by capillary. According to the results, good correspondence between simulated condition and real site exposure was obtained

  15. Surface Modification using Plasma treatments and Adhesion Peptide for Durable Tissue-Engineered Heart Valves

    International Nuclear Information System (INIS)

    Jung, Young mee; Kim, Soo Hyun

    2010-01-01

    Artificial heart valves are used in valvular heart diseases, but these valves have disadvantages that they cannot grow, repair and remodel. In current study, the strategies to development of in vitro cultured functional tissue by tissue engineering is available to heart valve disease. In the point of using viable autolougous cells, tissue engineered heart valves have some advantage to include that they can repair, remodel, and grow. Because heart valve is placed under the strong shear stress condition by pumping of heart, the durability of tissue-engineered heart valves is now questionable. The purpose of the study is to evaluate of the durability of tissue engineered heart valve with surface modified scaffolds under hemodynamic conditions

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

    International Nuclear Information System (INIS)

    Moon, Seong In; Cho, Il Je; Woo, Chang Su; Kim, Wan Doo

    2011-01-01

    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

  17. Report on the behalf of sustainable development and land planning commission of a bill aiming at prohibiting the exploration and exploitation on non conventional hydrocarbons, at abrogating exclusive search permits for non conventional hydrocarbon mines, and to ensure more transparency in the mining code; Rapport fait au nom de la Commission du Developpement Durable et de l'Amenagement du Territoire sur la proposition de loi, visant a interdire l'exploration et l'exploitation des hydrocarbures non conventionnels, a abroger les permis exclusifs de recherche de mines d'hydrocarbures non conventionnels et a assurer plus de transparence dans le code minier (n. 3690)

    Energy Technology Data Exchange (ETDEWEB)

    Chanteguet, J.P.

    2011-07-01

    In the first part of this report, the author (from the opposition party) outlines the opacity of the attribution procedure defined in the mining code for search permits, the lack of recognition of the citizen mobilization, and the inefficient and inapplicable character of the law of 2001 on the search for non conventional hydrocarbon mining sites. In the second part, the author outlines the need for an environment-friendly energy strategy, while recalling the necessity of protection of the environment when exploiting subsoils, the necessity of implementing an energy transition, and the necessity to reform the mining law. The discussion of the commission about the bill articles is reported

  18. Method of immobilizing weapons plutonium to provide a durable, disposable waste product

    Science.gov (United States)

    Ewing, Rodney C.; Lutze, Werner; Weber, William J.

    1996-01-01

    A method of atomic scale fixation and immobilization of plutonium to provide a durable waste product. Plutonium is provided in the form of either PuO.sub.2 or Pu(NO.sub.3).sub.4 and is mixed with and SiO.sub.2. The resulting mixture is cold pressed and then heated under pressure to form (Zr,Pu)SiO.sub.4 as the waste product.

  19. Chemical durability and characterization of nuclear waste forms in a hydrothermal environment

    International Nuclear Information System (INIS)

    Braithwaite, J.W.; Johnstone, J.K.

    1979-01-01

    The chemical durability of a simulated copper borosilicate waste glass and titanate waste ceramic has been studied in hydrothermal environments which could possibly be encountered in a bedded salt or sub-sealed waste isolation repository. The major parameters investigated which affect matrix corrosion and cesium solubilization include solution saturation and equilibrium phenomena, solution composition (especially the Mg +2 ion concentration), pH, particle size, temperature, and time

  20. A multi-scale investigation of the mechanical behavior of durable sisal fiber cement composites

    OpenAIRE

    Silva, Flávio de Andrade; Toledo Filho, Romildo D.; Mobasher, Barzin; Chawla, Nikhilesh

    2010-01-01

    Durable sisal fiber cement composites reinforced with long unidirectional aligned fibers were developed and their mechanical behavior was characterized in a multi-scale level. Tensile tests were performed in individual sisal fibers. Weibull statistics were used to quantify the degree of variability in fiber strength at different gage lengths. The fiber-matrix pull-out behavior was evaluated at several curing ages and embedded lengths. The composite's mechanical response was measured under dir...

  1. Determination of the critical plane and durability estimation for a multiaxial cyclic loading

    Science.gov (United States)

    Burago, N. G.; Nikitin, A. D.; Nikitin, I. S.; Yakushev, V. L.

    2018-03-01

    An analytical procedure is proposed to determine the critical plane orientation according to the Findley criterion for the multiaxial cyclic loading. The cases of in-phase and anti-phase cyclic loading are considered. Calculations of the stress state are carried out for the system of the gas turbine engine compressor disk and blades for flight loading cycles. The formulas obtained are used for estimations of the fatigue durability of this essential element of structure.

  2. Hanford enhanced waste glass characterization. Influence of composition on chemical durability

    International Nuclear Information System (INIS)

    Fox, K. M.; Edwards, T. B.

    2016-01-01

    This report provides a review of the complete high-level waste (HLW) and low-activity waste (LAW) data sets for the glasses recently fabricated at Pacific Northwest National Laboratory and characterized at Savannah River National Laboratory (SRNL). The review is from the perspective of relating the chemical durability performance to the compositions of these study glasses, since the characterization work at SRNL focused on chemical analysis and ASTM Product Consistency Test (PCT) performance.

  3. Obtaining of coffee varieties with durable resistance to illnesses, using the genetic diversity as improvement strategy

    International Nuclear Information System (INIS)

    Moreno Ruiz, German

    2004-01-01

    With the purpose of producing improved coffee varieties with resistance to the leaf rust (Hemileia vastatrix), the national federation of coffee growers of Colombia initiated in 1970 a research program, whose first results achieved in 1982 were the abstention of the Colombia coffee variety. The use of genetic variability as a strategy in plant breeding for a durable resistance is discussed. In addition, the breeding outline is described and the main features of the developed materials are presented

  4. A study on the effects of seawater on the durable life of concrete structures(II)

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Byung Hwan; Jang, Bong Suk; Jang, Seung Yeop; Jeon, Se Jin; Yu, Yeong; Park, Dae Gyun; Hyeong, Sang Soo [Seoul National Univ., Seoul (Korea, Republic of)

    1999-02-15

    Recently, large scale concrete structures such as nuclear power plants and offshore structures are actively being built in this country. These structures are subject to heavy attack due to seawater environment. A reasonable consideration for corrosion has not been paid to the structures in the past decades due to insufficient research data and guidelines. The durability is emerging as one of the most important factors. In the design and construction of concrete structures. The purpose of the present study is, therefore, to explore the corrosion mechanism and penetration mechanism of chloride ion, and to establish the evaluation procedure of durability life of concrete structures. In this study, the chloride ion concentration of seawater around our country have been analyzed and the deterioration mechanism of concrete structures have been also analyzed. The penetration mechanism of seawater into the concrete has been also studied. To this end, a comprehensive experimental program has been setup. The major test variables include the type of cement and the type of mineral admixture. The strength test as well as corrosion test have been conducted to explore the effects of chloride ion penetration on the properties of concrete. The corrosion mechanism and the penetration of chloride ion into concrete structures have been studied. These results will allow the estimation of durable life of concrete structures in nuclear power plants. The experimental results and the developed theory in the present study can be efficiently used to analyze the chloride ion penetration and to estimate the durability of concrete structures In nuclear power plants. The present study may also provide strong basis to evaluate the remaining service life of concrete structures in nuclear power plants.

  5. Se servir des Objectifs de développement durable en tant qu'outil ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    19 oct. 2017 ... L'astuce, c'est de ne pas s'en tenir aux conclusions immédiates de la recherche et d'identifier des pistes d'actions publiques et privées, qu'il s'agisse des Objectifs de développement durable (ODD) ... Il est incontestable que notre recherche éclaire l'action sur le climat et les efforts de lutte anti-pauvreté.

  6. Pricing for a Durable-Goods Monopolist Under Rapid Sequential Innovation

    OpenAIRE

    Laura J. Kornish

    2001-01-01

    A durable-goods monopolist who will be introducing new and improved versions of his product must decide how to price his products, keeping in mind the relative attractiveness of the current and future products. Dhebar (1994) has shown that if technology is changing too quickly and the producer cannot credibly commit to future prices and quality, then no equilibrium strategy exists. That is, there is no credible strategy for the future product that the producer can commit to in the first perio...

  7. Les SIG-P au service d'une gestion durable des ressources ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les SIG-P au service d'une gestion durable des ressources naturelles et de la sécurité alimentaire en Afrique. Les pays africains ont besoin de données convenables aux fins de la formulation et de la mise en oeuvre de politiques et de stratégies de sécurité alimentaire systématiques et cohérentes. Ces pays disposent de ...

  8. The durability of public goods changes the dynamics and nature of social dilemmas.

    Directory of Open Access Journals (Sweden)

    Sam P Brown

    Full Text Available An implicit assumption underpins basic models of the evolution of cooperation, mutualism and altruism: The benefits (or pay-offs of cooperation and defection are defined by the current frequency or distribution of cooperators. In social dilemmas involving durable public goods (group resources that can persist in the environment-ubiquitous from microbes to humans this assumption is violated. Here, we examine the consequences of relaxing this assumption, allowing pay-offs to depend on both current and past numbers of cooperators. We explicitly trace the dynamic of a public good created by cooperators, and define pay-offs in terms of the current public good. By raising the importance of cooperative history in determining the current fate of cooperators, durable public goods cause novel dynamics (e.g., transient increases in cooperation in Prisoner's Dilemmas, oscillations in Snowdrift Games, or shifts in invasion thresholds in Stag-hunt Games, while changes in durability can transform one game into another, by moving invasion thresholds for cooperation or conditions for coexistence with defectors. This enlarged view challenges our understanding of social cheats. For instance, groups of cooperators can do worse than groups of defectors, if they inherit fewer public goods, while a rise in defectors no longer entails a loss of social benefits, at least not in the present moment (as highlighted by concerns over environmental lags. Wherever durable public goods have yet to reach a steady state (for instance due to external perturbations, the history of cooperation will define the ongoing dynamics of cooperators.

  9. Effects of rate-of-return regulation on the intensity of use and durability of capital

    Energy Technology Data Exchange (ETDEWEB)

    Epple, D [Carnegie-Mellon Univ., Pittsburgh, PA; Zelenitz, A

    1979-10-01

    It has been suggested that rate-of-return regulation reduces the incentives for technically efficient management, because regulation eliminates much of the gain firms might normally expect to realize from such efficiency. Rather than relying upon notions of managerial slack or X-inefficiency, this paper demonstrates that under-utilization of existing capital and a suboptimal choice of the capital stock's durability can be explained as rational profit-maximizing responses to the regulatory incentives. 11 references.

  10. Bond durability of universal adhesive to bovine enamel using self-etch mode.

    Science.gov (United States)

    Suzuki, Soshi; Takamizawa, Toshiki; Imai, Arisa; Tsujimoto, Akimasa; Sai, Keiichi; Takimoto, Masayuki; Barkmeier, Wayne W; Latta, Mark A; Miyazaki, Masashi

    2018-04-01

    The purpose of this study was to examine the enamel bond durability of universal adhesives in the self-etch mode under 2-year water storage and thermal cycling conditions. Three commercially available universal adhesives and a gold standard two-step self-etch adhesive were used. Ten specimens of bovine enamel were prepared per test group, and shear bond strength (SBS) was measured to determine the bonding durability after thermal cycling (TC) or long-term water storage (WS). The bonded specimens were divided into three groups: (1) specimens subjected to TC, where the bonded specimens were stored in 37 °C distilled water for 24 h before being subjected to 3000, 10,000, 20,000 or 30,000 TC; (2) specimens stored in 37 °C distilled water for 3 months, 6 months, 1 year or 2 year; and (3) specimens stored in 37 °C distilled water for 24 h, serving as a baseline. The two-step self-etch adhesive showed significantly higher SBS than the universal adhesives tested, regardless of the type of degradation method. All universal adhesives showed no significant enamel SBS reductions in TC and WS, when compared to baseline and the other degradation conditions. Compared to the bond strengths obtained with the two-step self-etch adhesive, significantly lower bond strengths were obtained with universal adhesives. However, the enamel bond durability of universal adhesives was relatively stable under both degradation conditions tested. The present data indicate that the enamel bond durability of universal adhesives in the self-etch mode might be sufficient for clinical use.

  11. Sales drive advertising expenditures: Evidence for consumer packaged and durable goods in Germany

    OpenAIRE

    Lischka, Juliane A; Kienzler, Stephanie; Mellmann, Ulrike

    2014-01-01

    The relation between sales and advertising is both complex and diverse. Whether advertising activities drive or follow sales is still unclear. We uncover this relation distinguishing between consumer packaged goods (CPG) and durable consumer goods (DCG) industries. We fit vector autoregressive models to sales and advertising expenditures of four CPG and three DCG industries in Germany from 1991 q1 to 2009 q4. Findings reveal that advertising expenditures do not increase total sales of industr...

  12. Durability-Based Design Criteria for a Chopped-Glass-Fiber Automotive Structural Composite; TOPICAL

    International Nuclear Information System (INIS)

    Battiste, R.L.; Corum, J.M.; Ren, W.; Ruggles, M.B.

    1999-01-01

    This report provides recommended durability-based design criteria for a chopped-glass-fiber reinforced polymeric composite for automotive structural applications. The criteria closely follow the framework of an earlier criteria document for a continuous-strand-mat (CSM) glass-fiber reference composite. Together these design criteria demonstrate a framework that can be adapted for future random-glass-fiber composites for automotive structural applications

  13. Durability of anti-graffiti coatings on stone: natural vs accelerated weathering.

    Directory of Open Access Journals (Sweden)

    Paula M Carmona-Quiroga

    Full Text Available Extending the use of novel anti-graffiti coatings to built heritage could be of particular interest providing the treatments are efficient enough in facilitating graffiti removal and long-lasting to maintain their protective properties without interfering with the durability of the substrates. However, studies of the durability of these coatings are scarce and have been mainly carried out under accelerated weathering conditions, the most common practice for assessing the durability of materials but one that does not reproduce accurately natural working conditions. The present study aimed to assess the durability of the anti-graffiti protection afforded by two anti-graffiti treatments (a water dispersion of polyurethane with a perfluoropolyether backbone and a water based crystalline micro wax on Portland limestone and Woodkirk sandstone after 1 year of outdoor exposure in the South of England with periodic painting and cleaning episodes taking place. A parallel study under artificial weathering conditions in a QUV chamber for 2000 hours was also carried out. Changes to the coatings were assessed by measuring colour, gloss, water-repellency, roughness and microstructure, the latter through micro-Raman and optical microscope observations, periodically during the experiments. The results show that both anti-graffiti treatments deteriorated under both artificial and natural weathering conditions. For the polyurethane based anti-graffiti treatment, artificial ageing produced more deterioration than 1 year of outdoor exposure in the south of England due to loss of adhesion from the stones, whereas for micro wax coating there were no substantial differences between the two types of weathering.

  14. A Theory of Finitely Durable Goods Monopoly with Used-Goods Market and Transaction Costs

    OpenAIRE

    S. Huang; Y. Yang; K. Anderson

    2001-01-01

    We construct a dynamic game to model a monopoly of finitely durable goods. The solution concept is Markov-perfect equilibria with general equilibria embedded in every time period. Our model is flexible enough to simultaneously explain or accommodate many commonly observed phenomena or stylized facts, such as concurrent leasing and selling, active secondary markets for used goods, heterogeneous consumers, endogenous consumption patterns, depreciation, an infinite time horizon, and nontrivial t...

  15. Durability of anti-graffiti coatings on stone: natural vs accelerated weathering.

    Science.gov (United States)

    Carmona-Quiroga, Paula M; Jacobs, Robert M J; Martínez-Ramírez, Sagrario; Viles, Heather A

    2017-01-01

    Extending the use of novel anti-graffiti coatings to built heritage could be of particular interest providing the treatments are efficient enough in facilitating graffiti removal and long-lasting to maintain their protective properties without interfering with the durability of the substrates. However, studies of the durability of these coatings are scarce and have been mainly carried out under accelerated weathering conditions, the most common practice for assessing the durability of materials but one that does not reproduce accurately natural working conditions. The present study aimed to assess the durability of the anti-graffiti protection afforded by two anti-graffiti treatments (a water dispersion of polyurethane with a perfluoropolyether backbone and a water based crystalline micro wax) on Portland limestone and Woodkirk sandstone after 1 year of outdoor exposure in the South of England with periodic painting and cleaning episodes taking place. A parallel study under artificial weathering conditions in a QUV chamber for 2000 hours was also carried out. Changes to the coatings were assessed by measuring colour, gloss, water-repellency, roughness and microstructure, the latter through micro-Raman and optical microscope observations, periodically during the experiments. The results show that both anti-graffiti treatments deteriorated under both artificial and natural weathering conditions. For the polyurethane based anti-graffiti treatment, artificial ageing produced more deterioration than 1 year of outdoor exposure in the south of England due to loss of adhesion from the stones, whereas for micro wax coating there were no substantial differences between the two types of weathering.

  16. Preparation of durable insecticide cotton fabrics through sol–gel treatment with permethrin

    OpenAIRE

    Ardanuy Raso, Mònica; Faccini, Mirko; Amantia, David; Aubouy, Laurent; Borja, Guadalupe

    2014-01-01

    This paper presents the development of an industrially viable procedure for the fabrication of durable insecticide textiles based on the sol–gel technique. Permethrin was incorporated on cotton fabrics by a silicon oxide nanocoating applied by conventional padding followed by curing. The effect of the sol–gel process parameters, such as silica solid content and the permethrin/tetraethyl orthosilicate (TEOS) ratio on the insecticide activity and on the textile properties of the resulting fabri...

  17. The Effects of Design Strength, Fly Ash Content and Curing Method on Compressive Strength of High Volume Fly Ash Concrete: A Design of Experimental

    OpenAIRE

    Solikin Mochamad; Setiawan Budi

    2017-01-01

    High volume fly ash concrete becomes one of alternatives to produce green concrete as it uses waste material and significantly reduces the utilization of Portland cement in concrete production. Although using less cement, its compressive strength is comparable to ordinary Portland cement (hereafter OPC) and the its durability increases significantly. This paper reports investigation on the effect of design strength, fly ash content and curing method on compressive strength of High Volume Fly ...

  18. Durability predictions from rate of diffusion testing of normal portland cement, fly ash, and slag concrete

    International Nuclear Information System (INIS)

    Philipose, K.E.

    1991-09-01

    A waste repository for the belowground disposal of low-level radioactive waste, labelled IRUS (Intrusion Resistant Underground Structure), is planned at the Chalk River Laboratories. It relies greatly on the durability of concrete for a minimum of 500 years of service life. A research program based on laboratory testing to design a durable concrete and predict its useful engineered service life is in progress. The durability of concrete depends on its resistance to deterioration from both internal and external causes. Since the rate of degradation depends to a major extent on the rate of ingress of aggressive ions into concrete, laboratory testing is in progress to establish the diffusion rates of chlorides and sulphate ions. A total of 1000 concrete specimens and 500 paste specimens are being exposed at 22 degrees and 45 degrees C to twenty-five different combinations of corrosive agents, including CO 2 . Procedures to measure the ionic penetration profile and to determine the factors controlling diffusion of ions in the various concretes have been developed. The paper presents the initial results from the research program and the longevity predictions to qualify concretes for the IRUS waste repository, based on 16 months of diffusion testing on laboratory specimens

  19. Increase of operational reliability and durability of square sectoral working bodies of flexible screw conveyors

    Directory of Open Access Journals (Sweden)

    O.L. Lyashuk

    2017-12-01

    Full Text Available The construction of the device for guiding screw sectional working bodies of increased operational reliability and durability and the method of determination of the force of guiding the design parameters are given. Two main methods of manufacturing screw mechanisms of machines of various service purposes were investigated and it was established that twisted screws, in terms of their strength and performance, considerably exceed rolling stock. The design of the device for manufacturing screw working bodies of conveyors by means of cutting by periodic and continuous methods, as the most reliable in operation, is developed. The specifics of their work are due to various operations of technological processes, as well as physical and mechanical properties of goods, determine the nomenclature and design parameters of screw mechanisms (SM. In studying the processes of forming screw spirals, the basic precision characteristics of the methods of drilling and rolling are established. A comparative study of two main methods in terms of their operational and durable capabilities has been carried out. An important factor determining the reliability and durability of a screw is the difference in the thickness of the inner and outer edges.

  20. Research of Tool Durability in Surface Plastic Deformation Processing by Burnishing of Steel Without Metalworking Fluids

    Science.gov (United States)

    Grigoriev, S. N.; Bobrovskij, N. M.; Melnikov, P. A.; Bobrovskij, I. N.

    2017-05-01

    Modern vector of development of machining technologies aimed at the transition to environmentally safe technologies - “green” technologies. The concept of “green technology” includes a set of signs of knowledge intended for practical use (“technology”). One of the ways to improve the quality of production is the use of surface plastic deformation (SPD) processing methods. The advantage of the SPD is a capability to combine effects of finishing and strengthening treatment. The SPD processing can replace operations: fine turning, grinding or polishing. The SPD is a forceful contact impact of indentor on workpiece’s surface in condition of their relative motion. It is difficult to implement the core technology of the SPD (burnishing, roller burnishing, etc.) while maintaining core technological advantages without the use of lubricating and cooling technology (metalworking fluids, MWF). The “green” SPD technology was developed by the authors for dry processing and has not such shortcomings. When processing with SPD without use of MWF requirements for tool’s durability is most significant, especially in the conditions of mass production. It is important to determine the period of durability of tool at the design stage of the technological process with the purpose of wastage preventing. This paper represents the results of durability research of natural and synthetic diamonds (polycrystalline diamond - ASPK) as well as precision of polycrystalline superabrasive tools made of dense boron nitride (DBN) during SPD processing without application of MWF.