WorldWideScience

Sample records for concrete overlays

  1. Improving concrete overlay construction.

    Science.gov (United States)

    2010-03-01

    Several road construction projects involving concrete overlays at the state and county levels in Iowa in 2009 were studied for : construction techniques and methods. The projects that were evaluated consisted of sites in four Iowa counties: Osceola, ...

  2. Polyester polymer concrete overlay.

    Science.gov (United States)

    2013-01-01

    Polyester polymer concrete (PPC) was used in a trial application on a section of pavement that suffers from extensive studded tire wear. The purpose of the trial section is to determine if PPC is a possible repair strategy for this type of pavement d...

  3. Iowa task report : US 18 concrete overlay construction under traffic.

    Science.gov (United States)

    2012-05-01

    The National Concrete Pavement Technology Center, Iowa Department of Transportation, and Federal Highway Administration set out to demonstrate and document the design and construction of portland cement concrete (PCC) overlays on two-lane roadways wh...

  4. Forensic Study of Early Failures with Unbonded Concrete Overlays

    Science.gov (United States)

    2017-11-01

    A forensic investigation was conducted to identify failure mechanisms responsible for early failures of unbonded concrete overlays on selected projects in Ohio, including I-70 in Madison County, I-77 in Washington and Noble Counties, and I-90 in Lake...

  5. Comparative evaluation of concrete sealers and multiple layer polymer concrete overlays. Interim report no. 1.

    Science.gov (United States)

    1987-01-01

    The report presents comparisons of initial evaluations of several concrete sealers and multiple layer polymer concrete overlays. The sealers evaluated included a solvent-dlspersed epoxy, a water-dlspersed epoxy, a silane, and a high molecular weight ...

  6. Investigation of Tensile Creep of a Normal Strength Overlay Concrete.

    Science.gov (United States)

    Drexel, Martin; Theiner, Yvonne; Hofstetter, Günter

    2018-06-12

    The present contribution deals with the experimental investigation of the time-dependent behavior of a typical overlay concrete subjected to tensile stresses. The latter develop in concrete overlays, which are placed on existing concrete structures as a strengthening measure, due to the shrinkage of the young overlay concrete, which is restrained by the substrate concrete. Since the tensile stresses are reduced by creep, creep in tension is investigated on sealed and unsealed specimens, loaded at different concrete ages. The creep tests as well as the companion shrinkage tests are performed in a climatic chamber at constant temperature and constant relative humidity. Since shrinkage depends on the change of moisture content, the evolution of the mass water content is determined at the center of each specimen by means of an electrolytic resistivity-based system. Together with the experimental results for compressive creep from a previous study, a consistent set of time-dependent material data, determined for the same composition of the concrete mixture and on identical specimens, is now available. It consists of the hygral and mechanical properties, creep and shrinkage strains for both sealed and drying conditions, the respective compliance functions, and the mass water contents in sealed and unsealed, loaded and load-free specimens.

  7. Latex-modified fiber-reinforced concrete bridge deck overlay : construction/interim report.

    Science.gov (United States)

    1993-06-01

    Latex-modified concrete (LMC) is Portland cement concrete (PCC) with an admixture of latex. LMC is considered to be nearly impermeable to chlorides and is extensively used to construct bridge deck overlays. Unfortunately, some of these overlays have ...

  8. Application of Interfacial Propagation and Kinking Crack Concept to ECC/Concrete Overlay Repair System

    Directory of Open Access Journals (Sweden)

    Yaw ChiaHwan

    2014-01-01

    Full Text Available Research on the application of ultraductile engineered cementitious composite (ECC as overlay in the repair of deteriorated concrete structures is performed in this paper. Also, interfacial crack kinking and trapping mechanism experimentally observed in ECC/concrete overlay repair system are described by comparison of toughness and energy release rate. The mechanism involves cycles of extension, kinking, and arrest of interfacial crack into the overlay. Experimental testing of overlay repair system reveals significant improvements in load carrying capacity and ductility over conventional concrete overlay. The commonly observed overlay system failure mode of delamination or spalling is eliminated when ECC is applied. These failure modes are suppressed when ECC is used as an ideal and durable candidate overlay repair material.

  9. Performance polymeric concrete with synthetic fiber reinforcement against reflective cracking in rigid pavement overlay

    International Nuclear Information System (INIS)

    Khan, N.U.; Khan, B.

    2012-01-01

    Cement concrete pavements are used for heavy traffic loads throughout the world owing to its better and economical performance. Placing of a concrete overlay on the existing pavement is the most prevalent rehabilitating method for such pavements, however, the problem associated with the newly placed overlay is the occurrence of reflective cracking. This paper presents an assessment of the performance of polymeric concrete with synthetic fiber reinforcement against reflective cracking in an overlay system. The performance of polymeric concrete with synthetic fibers as an overlay material is measured in terms of the load-deflection, strain-deflection and load-strain behavior of beams of the polymeric concrete. For this purpose, five types of beams having different number of fiber wires and position are tested for flexure strength. Deflection/strains for each increment of load are recorded. In addition, cubes of plain concrete and of concrete with synthetic fiber needles were tested after 7 and 28 days for compressive strengths. Finite element models in ANSYS software for the beams have also been developed. Beams with greater number of longitudinal fiber wires displayed relatively better performance against deflection whilst beams with synthetic fiber needles showed better performance against strains. Thus, polymeric concrete overlay with fiber reinforcement will serve relatively better against occurrence of reflective cracking. (author)

  10. Utilizing Lab Tests to Predict Asphalt Concrete Overlay Performance

    Science.gov (United States)

    2017-12-01

    A series of five experimental projects and three demonstration projects were constructed to better understand the performance of pavement overlays using various levels of asphalt binder replacement (ABR) from reclaimed asphalt pavement (RAP), recycle...

  11. Axial compression behavior of concrete masonry wallettes strengthened with cement mortar overlays

    Directory of Open Access Journals (Sweden)

    F. L. De Oliveira

    Full Text Available This paper presents the results of a series of axial compression tests on concrete block wallettes coated with cement mortar overlays. Different types of mortars and combinations with steel welded meshes and fibers were tested. The experimental results were discussed based on different theoretical approaches: analytical and Finite Element Method models. The main conclusions are: a the application of mortar overlays increases the wall strength, but not in a uniform manner; b the strengthening efficiency of wallettes loaded in axial compression is not proportional to the overlay mortar strength because it can be affected by the failure mechanisms of the wall; c steel mesh reinforced overlays in combination with high strength mortar show better efficiency, because the steel mesh mitigates the damage effects in the block wall and in the overlays themselves; d simplified theoretical methods of analysis as described in this paper can give satisfactory predictions of masonry wall behavior up to a certain level.

  12. Accelerated testing for studying pavement design and performance (FY 2000) : effectiveness of fiber reinforced and plain, ultra-thin concrete overlays on Portland Cement Concrete Pavement (PCCP).

    Science.gov (United States)

    2003-11-01

    The objective of the research was to compare the performance of fiber reinforced and plain PCC concrete overlay when used as a thin non-dowelled overlay on top of a rubblized, distressed concrete pavement. The experiment was conducted at the Accelera...

  13. RESTORING A DAMAGED 16-YEAR -OLD INSULATING POLYMER CONCRETE DIKE OVERLAY: REPAIR MATERIALS AND TECHNOLOGIES.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    The objective of this program was to design and formulate organic polymer-based material systems suitable for repairing and restoring the overlay panels of insulating lightweight polymer concrete (ILPC) from the concrete floor and slope wall of a dike at KeySpan liquefied natural gas (LNG) facility in Greenpoint, Brooklyn, NY, just over sixteen years ago. It also included undertaking a small-scale field demonstration to ensure that the commercial repairing technologies were applicable to the designed and formulated materials.

  14. Effects of concrete moisture on polymer overlay bond over new concrete : [technical summary].

    Science.gov (United States)

    2015-06-01

    Epoxy polymer overlays have been used for decades on existing bridge decks to protect : the deck and extend its service life. The polymer overlays ability to seal a bridge deck : is now being specified for new construction. Questions exist about t...

  15. Performance of thin bonded epoxy overlays on asphalt and concrete bridge deck surfaces.

    Science.gov (United States)

    2014-06-01

    This study is the evaluation of two thin bonded epoxy overlays: SafeLane (marketed by Cargill), and Flexogrid : (developed by PolyCarb). SafeLane is advertised as an anti-skid/anti-icing overlay that stores deicing chemicals for : release during wint...

  16. Cracking and debonding of a thin fiber reinforced concrete overlay : research brief.

    Science.gov (United States)

    2017-03-01

    Experimental tests found that the tensile interfacial energy : increased with fiber-reinforcement. Also bond tests indicated : that interfacial fracture occurred through the overlay mixture and : was proportional to the number of fibers which interse...

  17. Distributed fiber optic sensor-enhanced detection and prediction of shrinkage-induced delamination of ultra-high-performance concrete overlay

    Science.gov (United States)

    Bao, Yi; Valipour, Mahdi; Meng, Weina; Khayat, Kamal H.; Chen, Genda

    2017-08-01

    This study develops a delamination detection system for smart ultra-high-performance concrete (UHPC) overlays using a fully distributed fiber optic sensor. Three 450 mm (length) × 200 mm (width) × 25 mm (thickness) UHPC overlays were cast over an existing 200 mm thick concrete substrate. The initiation and propagation of delamination due to early-age shrinkage of the UHPC overlay were detected as sudden increases and their extension in spatial distribution of shrinkage-induced strains measured from the sensor based on pulse pre-pump Brillouin optical time domain analysis. The distributed sensor is demonstrated effective in detecting delamination openings from microns to hundreds of microns. A three-dimensional finite element model with experimental material properties is proposed to understand the complete delamination process measured from the distributed sensor. The model is validated using the distributed sensor data. The finite element model with cohesive elements for the overlay-substrate interface can predict the complete delamination process.

  18. Unbonded portland cement concrete overlay/pavement monitoring with integrated grating and scattering optical fiber sensors.

    Science.gov (United States)

    2014-06-01

    This report summarizes the findings and results from a laboratory and field study on the strain distribution : and crack development in 3 thick concrete panels cast on top of existing concrete pavements as a rapid : rehabilitation strategy for roa...

  19. Overlay field application program, Pennsylvania US-119.

    Science.gov (United States)

    2010-11-01

    The Concrete Overly Filed Application program is administered by FHWA and the National Concrete Pavement Technology Center (CP Tech Center). The overall objective of this program is to increase the awareness and knowledge of concrete overlay applicat...

  20. Pavement structure mechanics response of flexible on semi-flexible overlay that based on the old cement concrete pavement damage

    Directory of Open Access Journals (Sweden)

    Jiang Ruinan

    2015-01-01

    Full Text Available The old cement pavement damage status directly affect the design of the paving renovation. Based on the state of the old road investigation, combined with the research data at home and abroad, use the control index that average deflection, deflection value and CBR value to determine the reasonable time to overlay. Draw up the typical pavement structure according to the principle of combination of old cement pavement overlay structure design, and calculated that the tensile stress and shear stress in asphalt layer ,semi-flexible layer and the tensile in the old cement pavement adopting BISA3.0 statics finite element analysis model when modulus in the old road was diminishing. Use the computed result to analyses the influence of old road damage condition the influence of pavement structure.

  1. Tack coat optimization for HMA overlays laboratory testing.

    Science.gov (United States)

    2008-09-01

    Interface bonding between hot-mix asphalt (HMA) overlays and Portland cement concrete (PCC) pavements can be one of the most : significant factors affecting overlay service life. Various factors may affect the bonding condition at the interface, incl...

  2. Tack coat optimization for HMA overlays : accelerated pavement test report.

    Science.gov (United States)

    2009-02-01

    Interface bonding between hot-mix asphalt (HMA) overlays and Portland cement concrete (PCC) pavements is one : of the most significant factors affecting overlay service life. This study was performed to quantify the effects of HMA type, : tack coat t...

  3. Concrete

    DEFF Research Database (Denmark)

    2015-01-01

    Concrete is a component of coherent transition between a concrete base and a wooden construction. The structure is based on a quantity of investigations of the design possibilities that arise when combining digital fabrication tools and material capacities. Through tangible experiments the project...... specific for this to happen. And the knowledge and intention behind the drawing becomes specialised through the understanding of the fabrication processes and their affect on the materials.The structure Concrete is a result of a multi-angled kerf series in ash wood and a concrete base. The ash wood is cut...... using a 5-axis CNC router with a thin saw blade attached. The programming of the machining results in variations of kerfs that lets the ash wood twist into unique shapes.The shapes of the revolving ash ribbons continue into the concrete creating a cohesive shape. The form for the concrete itself is made...

  4. Overlay accuracy fundamentals

    Science.gov (United States)

    Kandel, Daniel; Levinski, Vladimir; Sapiens, Noam; Cohen, Guy; Amit, Eran; Klein, Dana; Vakshtein, Irina

    2012-03-01

    Currently, the performance of overlay metrology is evaluated mainly based on random error contributions such as precision and TIS variability. With the expected shrinkage of the overlay metrology budget to DBO (1st order diffraction based overlay). It is demonstrated that the sensitivity of DBO to overlay mark asymmetry is larger than the sensitivity of imaging overlay. Finally, we show that a recently developed measurement quality metric serves as a valuable tool for improving overlay metrology accuracy. Simulation results demonstrate that the accuracy of imaging overlay can be improved significantly by recipe setup optimized using the quality metric. We conclude that imaging overlay metrology, complemented by appropriate use of measurement quality metric, results in optimal overlay accuracy.

  5. Concrete

    OpenAIRE

    Kruse Aagaard, Anders

    2015-01-01

    Concrete is a component of coherent transition between a concrete base and a wooden construction. The structure is based on a quantity of investigations of the design possibilities that arise when combining digital fabrication tools and material capacities.Through tangible experiments the project discusses materiality and digitally controlled fabrications tools as direct expansions of the architect’s digital drawing and workflow. The project sees this expansion as an opportunity to connect th...

  6. VT Data - Overlay District 20170407, Burlington

    Data.gov (United States)

    Vermont Center for Geographic Information — The following Overlay District Data is included:Design Review OverlayInstitutional Core Campus OverlayRH Density Bonus OverlayNatural Resource Protection OverlayRL...

  7. RADAR PPI Scope Overlay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — RADAR PPI Scope Overlays are used to position a RADAR image over a station at the correct resolution. The archive maintains several different RADAR resolution types,...

  8. Improving concrete overlay construction : executive summary.

    Science.gov (United States)

    2010-06-01

    As the US highway system ages and available funding diminishes, transportation agencies : are looking for effective methods for preserving and extending the life of existing : pavements. These agencies are also being encouraged to minimize constructi...

  9. Overlay improvement methods with diffraction based overlay and integrated metrology

    Science.gov (United States)

    Nam, Young-Sun; Kim, Sunny; Shin, Ju Hee; Choi, Young Sin; Yun, Sang Ho; Kim, Young Hoon; Shin, Si Woo; Kong, Jeong Heung; Kang, Young Seog; Ha, Hun Hwan

    2015-03-01

    To accord with new requirement of securing more overlay margin, not only the optical overlay measurement is faced with the technical limitations to represent cell pattern's behavior, but also the larger measurement samples are inevitable for minimizing statistical errors and better estimation of circumstance in a lot. From these reasons, diffraction based overlay (DBO) and integrated metrology (IM) were mainly proposed as new approaches for overlay enhancement in this paper.

  10. VT Data - Overlay District 20170802, Shelburne

    Data.gov (United States)

    Vermont Center for Geographic Information — The following Overlay Districts are included in the data:Lakeshore Conservation OverlyNeighborhood OverlayVillage Design Review OverlayVillage Core OverlayWater...

  11. VT Data - Overlay District 20170710, South Burlington

    Data.gov (United States)

    Vermont Center for Geographic Information — Overlay data for the City of South Burlington included in this data:Flood Plain Overlay DistrictTraffic Overlay DistrictInterstate Highway Overlay DistrictScenic...

  12. VT Data - Overlay District 20170228, Richmond

    Data.gov (United States)

    Vermont Center for Geographic Information — The following overlay districts are included in the data:Shoreline Protection OverlayFlood Hazard OverlayDetails about these overlay districts, as well as zoning...

  13. Critical issues in overlay metrology

    International Nuclear Information System (INIS)

    Sullivan, Neal T.

    2001-01-01

    In this paper, following an overview of overlay metrology, the difficult relationship of overlay with device performance and yield is discussed and supported with several examples. This is followed by a discussion of the impending collision of metrology equipment performance and 'real' process tolerances for sub 0.18 um technologies. This convergence of tolerance and performance is demonstrated to lead to the current emergence of real-time overlay modeling in a feed-forward/feedback process environment and the associated metrology/sampling implications. This modeling takes advantage of the wealth of understanding concerning the systematic behavior of overlay registration errors. Finally, the impact of new process technologies (RET, OAI, CPSM, CMP, and etc.) on the measurement target is discussed and shown to de-stabilize overlay performance on standard overlay measurement target designs

  14. Overlay networks toward information networking

    CERN Document Server

    Tarkoma, Sasu

    2010-01-01

    With their ability to solve problems in massive information distribution and processing, while keeping scaling costs low, overlay systems represent a rapidly growing area of R&D with important implications for the evolution of Internet architecture. Inspired by the author's articles on content based routing, Overlay Networks: Toward Information Networking provides a complete introduction to overlay networks. Examining what they are and what kind of structures they require, the text covers the key structures, protocols, and algorithms used in overlay networks. It reviews the current state of th

  15. Photoelectron emission from thin overlayers

    International Nuclear Information System (INIS)

    Jablonski, A.

    2012-01-01

    Highlights: ► Weak influence of the support on photoemission from an overlayer. ► Accurate description of photoelectron intensity from overlayer by analytical theory. ► Method for overlayer thickness measurements based on analytical formalism. ► Influence of photoelectron elastic scattering on calculated thickness. -- Abstract: Photoelectron signal intensities calculated for a thin overlayer from theoretical models taking elastic photoelectron collisions into account are shown to be very weakly dependent on the substrate material. This result has been obtained for photoelectrons analyzed in XPS spectrometers equipped with typical X-ray sources, i.e. sources of Mg Kα and Al Kα radiation. Low sensitivity to the substrate material is due to the fact that trajectories of photoelectrons emitted in the overlayer and entering the substrate have a low probability to reach the analyzer without energy loss. On the other hand, the signal intensity of photoelectrons emitted in the overlayer is found to be distinctly affected by elastic photoelectron scattering. Consequently, a theoretical model that can accurately describe the photoelectron intensity from an overlayer deposited on any material (e.g. on a substrate of the same material as the overlayer) can be a useful basis for a universal and convenient method for determination of the overlayer thickness. It is shown that the formalism derived from the kinetic Boltzmann equation within the so-called transport approximation satisfies these requirements. This formalism is postulated for use in overlayer-thickness measurements to avoid time-consuming Monte Carlo simulations of photoelectron transport, and also to circumvent problems with determining the effective attenuation lengths for overlayer/substrate systems.

  16. Longer Lasting Bridge Deck Overlays

    Science.gov (United States)

    2018-04-01

    The objective of this report is to determine the most effective method for bridge deck overlay construction and repair by assessing current practices; examining new products and technologies; and reviewing NCHRP (National Cooperative Highway Research...

  17. Accelerated testing for studying pavement design and performance (FY 2004) : thin bonded rigid overlay on PCCP and HMA (CISL experiment no. 13).

    Science.gov (United States)

    2009-03-01

    The thirteenth full-scale Accelerated Pavement Test (APT) experiment at the Civil Infrastructure Laboratory (CISL) : of Kansas State University aimed to determine the response and the failure mode of thin concrete overlays. Four : pavement structures...

  18. Heavy Vehicle Simulator aided evaluation of overlays on pavements with active cracks

    CSIR Research Space (South Africa)

    Viljoen, AW

    1987-07-01

    Full Text Available their effects by means of field data from actual pavements. The South African Heavy Simulator was also used to evaluate a variety of conventional and innovative asphaltic overlays on a severely cracked concrete pavement of which the mechanisms and extent...

  19. Retrofitting of Reinforced Concrete Beams using Reactive Powder Concrete (RPC)

    Science.gov (United States)

    Karthik, S.; Sundaravadivelu, Karthik

    2017-07-01

    Strengthening of existing damaged structures is one of the leading studies in civil engineering. The purpose of retrofitting is to structurally treat the member with an aim to restore the structure to its original strength. The focus of this project is to study the behaviour of damaged Reinforced Concrete beam retrofitted with Reactive Powder Concrete (RPC) Overlay. Reinforced concrete beams of length 1200 mm, width 100 mm and depth 200 mm were casted with M30 grade of concrete in the laboratory and cured for 28 days. One beam is taken as control and are tested under two point loading to find out ultimate load. Remaining beams are subjected to 90 % ultimate load of control beams. The partially damaged beams are retrofitted with Reactive Powder Concrete Overlay at the full tension face of the beam and side overlay depends upon the respectable retrofitting techniques with 10 mm and 20 mm thick layer to find optimum. Materials like steel fibres are added to enhance the ductility by eliminating coarse particle for homogeneity of the structure. Finally, the modes of failure for retrofitted beams are analysed experimentally under two point loading & compared the results with Control beam.

  20. Advanced overlay analysis through design based metrology

    Science.gov (United States)

    Ji, Sunkeun; Yoo, Gyun; Jo, Gyoyeon; Kang, Hyunwoo; Park, Minwoo; Kim, Jungchan; Park, Chanha; Yang, Hyunjo; Yim, Donggyu; Maruyama, Kotaro; Park, Byungjun; Yamamoto, Masahiro

    2015-03-01

    As design rule shrink, overlay has been critical factor for semiconductor manufacturing. However, the overlay error which is determined by a conventional measurement with an overlay mark based on IBO and DBO often does not represent the physical placement error in the cell area. The mismatch may arise from the size or pitch difference between the overlay mark and the cell pattern. Pattern distortion caused by etching or CMP also can be a source of the mismatch. In 2014, we have demonstrated that method of overlay measurement in the cell area by using DBM (Design Based Metrology) tool has more accurate overlay value than conventional method by using an overlay mark. We have verified the reproducibility by measuring repeatable patterns in the cell area, and also demonstrated the reliability by comparing with CD-SEM data. We have focused overlay mismatching between overlay mark and cell area until now, further more we have concerned with the cell area having different pattern density and etch loading. There appears a phenomenon which has different overlay values on the cells with diverse patterning environment. In this paper, the overlay error was investigated from cell edge to center. For this experiment, we have verified several critical layers in DRAM by using improved(Better resolution and speed) DBM tool, NGR3520.

  1. Evaluating diffraction-based overlay

    Science.gov (United States)

    Li, Jie; Tan, Asher; Jung, JinWoo; Goelzer, Gary; Smith, Nigel; Hu, Jiangtao; Ham, Boo-Hyun; Kwak, Min-Cheol; Kim, Cheol-Hong; Nam, Suk-Woo

    2012-03-01

    We evaluate diffraction-based overlay (DBO) metrology using two test wafers. The test wafers have different film stacks designed to test the quality of DBO data under a range of film conditions. We present DBO results using traditional empirical approach (eDBO). eDBO relies on linear response of the reflectance with respect to the overlay displacement within a small range. It requires specially designed targets that consist of multiple pads with programmed shifts. It offers convenience of quick recipe setup since there is no need to establish a model. We measure five DBO targets designed with different pitches and programmed shifts. The correlations of five eDBO targets and the correlation of eDBO to image-based overlay are excellent. The targets of 800nm and 600nm pitches have better dynamic precision than targets of 400nm pitch, which agrees with simulated results on signal/noise ratio. 3σ of less than 0.1nm is achieved for both wafers using the best configured targets. We further investigate the linearity assumption of eDBO algorithm. Simulation results indicate that as the pitch of DBO targets gets smaller, the nonlinearity error, i.e., the error in the overlay measurement results caused by deviation from ideal linear response, becomes bigger. We propose a nonlinearity correction (NLC) by including higher order terms in the optical response. The new algorithm with NLC improves measurement consistency for DBO targets of same pitch but different programmed shift, due to improved accuracy. The results from targets with different pitches, however, are improved marginally, indicating the presence of other error sources.

  2. Overlay metrology for double patterning processes

    Science.gov (United States)

    Leray, Philippe; Cheng, Shaunee; Laidler, David; Kandel, Daniel; Adel, Mike; Dinu, Berta; Polli, Marco; Vasconi, Mauro; Salski, Bartlomiej

    2009-03-01

    The double patterning (DPT) process is foreseen by the industry to be the main solution for the 32 nm technology node and even beyond. Meanwhile process compatibility has to be maintained and the performance of overlay metrology has to improve. To achieve this for Image Based Overlay (IBO), usually the optics of overlay tools are improved. It was also demonstrated that these requirements are achievable with a Diffraction Based Overlay (DBO) technique named SCOLTM [1]. In addition, we believe that overlay measurements with respect to a reference grid are required to achieve the required overlay control [2]. This induces at least a three-fold increase in the number of measurements (2 for double patterned layers to the reference grid and 1 between the double patterned layers). The requirements of process compatibility, enhanced performance and large number of measurements make the choice of overlay metrology for DPT very challenging. In this work we use different flavors of the standard overlay metrology technique (IBO) as well as the new technique (SCOL) to address these three requirements. The compatibility of the corresponding overlay targets with double patterning processes (Litho-Etch-Litho-Etch (LELE); Litho-Freeze-Litho-Etch (LFLE), Spacer defined) is tested. The process impact on different target types is discussed (CD bias LELE, Contrast for LFLE). We compare the standard imaging overlay metrology with non-standard imaging techniques dedicated to double patterning processes (multilayer imaging targets allowing one overlay target instead of three, very small imaging targets). In addition to standard designs already discussed [1], we investigate SCOL target designs specific to double patterning processes. The feedback to the scanner is determined using the different techniques. The final overlay results obtained are compared accordingly. We conclude with the pros and cons of each technique and suggest the optimal metrology strategy for overlay control in double

  3. Assessment and prediction of drying shrinkage cracking in bonded mortar overlays

    Energy Technology Data Exchange (ETDEWEB)

    Beushausen, Hans, E-mail: hans.beushausen@uct.ac.za; Chilwesa, Masuzyo

    2013-11-15

    Restrained drying shrinkage cracking was investigated on composite beams consisting of substrate concrete and bonded mortar overlays, and compared to the performance of the same mortars when subjected to the ring test. Stress development and cracking in the composite specimens were analytically modeled and predicted based on the measurement of relevant time-dependent material properties such as drying shrinkage, elastic modulus, tensile relaxation and tensile strength. Overlay cracking in the composite beams could be very well predicted with the analytical model. The ring test provided a useful qualitative comparison of the cracking performance of the mortars. The duration of curing was found to only have a minor influence on crack development. This was ascribed to the fact that prolonged curing has a beneficial effect on tensile strength at the onset of stress development, but is in the same time not beneficial to the values of tensile relaxation and elastic modulus. -- Highlights: •Parameter study on material characteristics influencing overlay cracking. •Analytical model gives good quantitative indication of overlay cracking. •Ring test presents good qualitative indication of overlay cracking. •Curing duration has little effect on overlay cracking.

  4. Assessment and prediction of drying shrinkage cracking in bonded mortar overlays

    International Nuclear Information System (INIS)

    Beushausen, Hans; Chilwesa, Masuzyo

    2013-01-01

    Restrained drying shrinkage cracking was investigated on composite beams consisting of substrate concrete and bonded mortar overlays, and compared to the performance of the same mortars when subjected to the ring test. Stress development and cracking in the composite specimens were analytically modeled and predicted based on the measurement of relevant time-dependent material properties such as drying shrinkage, elastic modulus, tensile relaxation and tensile strength. Overlay cracking in the composite beams could be very well predicted with the analytical model. The ring test provided a useful qualitative comparison of the cracking performance of the mortars. The duration of curing was found to only have a minor influence on crack development. This was ascribed to the fact that prolonged curing has a beneficial effect on tensile strength at the onset of stress development, but is in the same time not beneficial to the values of tensile relaxation and elastic modulus. -- Highlights: •Parameter study on material characteristics influencing overlay cracking. •Analytical model gives good quantitative indication of overlay cracking. •Ring test presents good qualitative indication of overlay cracking. •Curing duration has little effect on overlay cracking

  5. VT Data - Overlay District 20070306, Marlboro

    Data.gov (United States)

    Vermont Center for Geographic Information — Cartographic version of overlay district (surface water buffer), Marlboro, Vermont. Base zoning districts are in a separate shapefile. Data were originally created...

  6. How Concrete Is Concrete?

    Science.gov (United States)

    Gravemeijer, Koeno

    2011-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, "manipulatives", in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own,…

  7. Development of an Overlay Design Procedure for Composite Pavements

    Science.gov (United States)

    2017-09-01

    The composite overlay design procedure currently used by ODOT sometimes produces very large overlay thicknesses that are deemed structurally unnecessary, especially for composite pavements already with thick asphalt overlays. This study was initiated...

  8. Overlay accuracy with respect to device scaling

    Science.gov (United States)

    Leray, Philippe; Laidler, David; Cheng, Shaunee

    2012-03-01

    Overlay metrology performance is usually reported as repeatability, matching between tools or optics aberrations distorting the measurement (Tool induced shift or TIS). Over the last few years, improvement of these metrics by the tool suppliers has been impressive. But, what about accuracy? Using different target types, we have already reported small differences in the mean value as well as fingerprint [1]. These differences make the correctables questionable. Which target is correct and therefore which translation, scaling etc. values should be fed back to the scanner? In this paper we investigate the sources of these differences, using several approaches. First, we measure the response of different targets to offsets programmed in a test vehicle. Second, we check the response of the same overlay targets to overlay errors programmed into the scanner. We compare overlay target designs; what is the contribution of the size of the features that make up the target? We use different overlay measurement techniques; is DBO (Diffraction Based Overlay) more accurate than IBO (Image Based Overlay)? We measure overlay on several stacks; what is the stack contribution to inaccuracy? In conclusion, we offer an explanation for the observed differences and propose a solution to reduce them.

  9. Disordering kinetics in surface overlayers

    International Nuclear Information System (INIS)

    Jesina, A.; Tringides, M.C.

    1993-01-01

    The disordering kinetics of the O/W(110)-p(2x1)+p(2x2) overlayer, prepared initially in a well-ordered state, are studied with low-energy electron diffraction profile analysis. The decay of the peak intensity, used as a measure of the growing disorder, cannot be fitted to a power law as in the case of ordering processes. The full width at half maximum of the time-dependent structure factor S(q,t) is constant with time, which suggests that the average size remains constant. Diffusion activation energy extracted for the temperature dependence of the disordering is 1.0±0.05 eV, which is different from the value of 0.6 eV measured in ordering processes. The difference can be explained by the adsorbate-adsorbate interactions, which contribute differently to the diffusion barrier, in the two experiments

  10. The effect of individually-induced processes on image-based overlay and diffraction-based overlay

    Science.gov (United States)

    Oh, SeungHwa; Lee, Jeongjin; Lee, Seungyoon; Hwang, Chan; Choi, Gilheyun; Kang, Ho-Kyu; Jung, EunSeung

    2014-04-01

    In this paper, set of wafers with separated processes was prepared and overlay measurement result was compared in two methods; IBO and DBO. Based on the experimental result, theoretical approach of relationship between overlay mark deformation and overlay variation is presented. Moreover, overlay reading simulation was used in verification and prediction of overlay variation due to deformation of overlay mark caused by induced processes. Through this study, understanding of individual process effects on overlay measurement error is given. Additionally, guideline of selecting proper overlay measurement scheme for specific layer is presented.

  11. Diffraction based overlay re-assessed

    Science.gov (United States)

    Leray, Philippe; Laidler, David; D'havé, Koen; Cheng, Shaunee

    2011-03-01

    In recent years, numerous authors have reported the advantages of Diffraction Based Overlay (DBO) over Image Based Overlay (IBO), mainly by comparison of metrology figures of merit such as TIS and TMU. Some have even gone as far as to say that DBO is the only viable overlay metrology technique for advanced technology nodes; 22nm and beyond. Typically the only reported drawback of DBO is the size of the required targets. This severely limits its effective use, when all critical layers of a product, including double patterned layers need to be measured, and in-die overlay measurements are required. In this paper we ask whether target size is the only limitation to the adoption of DBO for overlay characterization and control, or are there other metrics, which need to be considered. For example, overlay accuracy with respect to scanner baseline or on-product process overlay control? In this work, we critically re-assess the strengths and weaknesses of DBO for the applications of scanner baseline and on-product process layer overlay control. A comprehensive comparison is made to IBO. For on product process layer control we compare the performance on critical process layers; Gate, Contact and Metal. In particularly we focus on the response of the scanner to the corrections determined by each metrology technique for each process layer, as a measure of the accuracy. Our results show that to characterize an overlay metrology technique that is suitable for use in advanced technology nodes requires much more than just evaluating the conventional metrology metrics of TIS and TMU.

  12. Overlay Spectrum Sharing using Improper Gaussian Signaling

    KAUST Repository

    Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

    2016-01-01

    in overlay cognitive radio system, where the secondary transmitter broadcasts a mixture of two different signals. The first signal is selected from the PGS scheme to match the primary message transmission. On the other hand, the second signal is chosen

  13. VT Data - Overlay District 20170419, Colchester

    Data.gov (United States)

    Vermont Center for Geographic Information — The following Overlay Districts are included in the data:General Development Four Commercial DistrictGeneral Development Four Openspace DistrictShoreland...

  14. A comparison of advanced overlay technologies

    Science.gov (United States)

    Dasari, Prasad; Smith, Nigel; Goelzer, Gary; Liu, Zhuan; Li, Jie; Tan, Asher; Koh, Chin Hwee

    2010-03-01

    The extension of optical lithography to 22nm and beyond by Double Patterning Technology is often challenged by CDU and overlay control. With reduced overlay measurement error budgets in the sub-nm range, relying on traditional Total Measurement Uncertainty (TMU) estimates alone is no longer sufficient. In this paper we will report scatterometry overlay measurements data from a set of twelve test wafers, using four different target designs. The TMU of these measurements is under 0.4nm, within the process control requirements for the 22nm node. Comparing the measurement differences between DBO targets (using empirical and model based analysis) and with image-based overlay data indicates the presence of systematic and random measurement errors that exceeds the TMU estimate.

  15. TRANSPARENT CONCRETE

    OpenAIRE

    Sandeep Sharma*, Dr. O.P. Reddy

    2017-01-01

    Transparent concrete is the new type of concrete introduced in todays world which carries special property of light transmitting due to presence of light Optical fibres. Which is also known as translucent concrete or light transmitting concrete, it is achieved by replacing coarse aggregates with transparent alternate materials (Optical fibres). The binding material in transparent concrete may be able to transmit light by using clear resins the concrete mix. The concrete used in industry in pr...

  16. Diffraction based overlay and image based overlay on production flow for advanced technology node

    Science.gov (United States)

    Blancquaert, Yoann; Dezauzier, Christophe

    2013-04-01

    One of the main challenges for lithography step is the overlay control. For the advanced technology node like 28nm and 14nm, the overlay budget becomes very tight. Two overlay techniques compete in our advanced semiconductor manufacturing: the Diffraction based Overlay (DBO) with the YieldStar S200 (ASML) and the Image Based Overlay (IBO) with ARCHER (KLA). In this paper we will compare these two methods through 3 critical production layers: Poly Gate, Contact and first metal layer. We will show the overlay results of the 2 techniques, explore the accuracy and compare the total measurement uncertainty (TMU) for the standard overlay targets of both techniques. We will see also the response and impact for the Image Based Overlay and Diffraction Based Overlay techniques through a process change like an additional Hardmask TEOS layer on the front-end stack. The importance of the target design is approached; we will propose more adapted design for image based targets. Finally we will present embedded targets in the 14 FDSOI with first results.

  17. How Concrete is Concrete

    OpenAIRE

    Koeno Gravemeijer

    2010-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two diff...

  18. Scatterometry or imaging overlay: a comparative study

    Science.gov (United States)

    Hsu, Simon C. C.; Pai, Yuan Chi; Chen, Charlie; Yu, Chun Chi; Hsing, Henry; Wu, Hsing-Chien; Kuo, Kelly T. L.; Amir, Nuriel

    2015-03-01

    Most fabrication facilities today use imaging overlay measurement methods, as it has been the industry's reliable workhorse for decades. In the last few years, third-generation Scatterometry Overlay (SCOL™) or Diffraction Based Overlay (DBO-1) technology was developed, along another DBO technology (DBO-2). This development led to the question of where the DBO technology should be implemented for overlay measurements. Scatterometry has been adopted for high volume production in only few cases, always with imaging as a backup, but scatterometry overlay is considered by many as the technology of the future. In this paper we compare imaging overlay and DBO technologies by means of measurements and simulations. We outline issues and sensitivities for both technologies, providing guidelines for the best implementation of each. For several of the presented cases, data from two different DBO technologies are compared as well, the first with Pupil data access (DBO-1) and the other without pupil data access (DBO-2). Key indicators of overlay measurement quality include: layer coverage, accuracy, TMU, process robustness and robustness to process changes. Measurement data from real cases across the industry are compared and the conclusions are also backed by simulations. Accuracy is benchmarked with reference OVL, and self-consistency, showing good results for Imaging and DBO-1 technology. Process sensitivity and metrology robustness are mostly simulated with MTD (Metrology Target Designer) comparing the same process variations for both technologies. The experimental data presented in this study was done on ten advanced node layers and three production node layers, for all phases of the IC fabrication process (FEOL, MEOL and BEOL). The metrology tool used for most of the study is KLA-Tencor's Archer 500LCM system (scatterometry-based and imaging-based measurement technologies on the same tool) another type of tool is used for DBO-2 measurements. Finally, we conclude that

  19. How Concrete is Concrete

    Directory of Open Access Journals (Sweden)

    Koeno Gravemeijer

    2010-07-01

    Full Text Available If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two different ways of making things concrete. Next another role of manipulatives, will be discussed, namely that of means for scaffolding and communication. In this role, manipulatives may function as means of support in a process that aims at helping students to build on their own thinking while constructing more sophisticated mathematics

  20. Enhacement of intrafield overlay using a design based metrology system

    Science.gov (United States)

    Jo, Gyoyeon; Ji, Sunkeun; Kim, Shinyoung; Kang, Hyunwoo; Park, Minwoo; Kim, Sangwoo; Kim, Jungchan; Park, Chanha; Yang, Hyunjo; Maruyama, Kotaro; Park, Byungjun

    2016-03-01

    As the scales of the semiconductor devices continue to shrink, accurate measurement and control of the overlay have been emphasized for securing more overlay margin. Conventional overlay analysis methods are based on the optical measurement of the overlay mark. However, the overlay data obtained from these optical methods cannot represent the exact misregistration between two layers at the circuit level. The overlay mismatch may arise from the size or pitch difference between the overlay mark and the real pattern. Pattern distortion, caused by CMP or etching, could be a source of the overlay mismatch as well. Another issue is the overlay variation in the real circuit pattern which varies depending on its location. The optical overlay measurement methods, such as IBO and DBO that use overlay mark on the scribeline, are not capable of defining the exact overlay values of the real circuit. Therefore, the overlay values of the real circuit need to be extracted to integrate the semiconductor device properly. The circuit level overlay measurement using CDSEM is time-consuming in extracting enough data to indicate overall trend of the chip. However DBM tool is able to derive sufficient data to display overlay tendency of the real circuit region with high repeatability. An E-beam based DBM(Design Based Metrology) tool can be an alternative overlay measurement method. In this paper, we are going to certify that the overlay values extracted from optical measurement cannot represent the circuit level overlay values. We will also demonstrate the possibility to correct misregistration between two layers using the overlay data obtained from the DBM system.

  1. Robotic weld overlay coatings for erosion control

    Science.gov (United States)

    The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterfalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in CFB's.

  2. On Adding Structure to Unstructured Overlay Networks

    Science.gov (United States)

    Leitão, João; Carvalho, Nuno A.; Pereira, José; Oliveira, Rui; Rodrigues, Luís

    Unstructured peer-to-peer overlay networks are very resilient to churn and topology changes, while requiring little maintenance cost. Therefore, they are an infrastructure to build highly scalable large-scale services in dynamic networks. Typically, the overlay topology is defined by a peer sampling service that aims at maintaining, in each process, a random partial view of peers in the system. The resulting random unstructured topology is suboptimal when a specific performance metric is considered. On the other hand, structured approaches (for instance, a spanning tree) may optimize a given target performance metric but are highly fragile. In fact, the cost for maintaining structures with strong constraints may easily become prohibitive in highly dynamic networks. This chapter discusses different techniques that aim at combining the advantages of unstructured and structured networks. Namely we focus on two distinct approaches, one based on optimizing the overlay and another based on optimizing the gossip mechanism itself.

  3. Exploring overlay journals: the RIOJA project

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    Researchers in cosmology and astrophysics depend on the arXiv repository for the registration and dissemination of their work, as well as for current awareness, yet they continue to submit papers to journals for review. Could rapid quality certification be overlaid directly onto the arXiv repository? This presentation introduces the RIOJA (Repository Interface to Overlaid Journal Archives) project, on which a group of cosmology researchers from the UK is working with UCL Library Services and Cornell University. The project is creating a tool to support the overlay of journals onto repositories, and will demonstrate a cosmology journal overlaid on top of arXiv. RIOJA will also work with the cosmology community to explore the social and economic aspects of journal overlay in this discipline: what other value, besides the quality stamp, does journal publication typically add? What are the costs of the ideal overlay journal for this community, and how could those costs be recovered? Would researchers real...

  4. KML Super Overlay to WMS Translator

    Science.gov (United States)

    Plesea, Lucian

    2007-01-01

    This translator is a server-based application that automatically generates KML super overlay configuration files required by Google Earth for map data access via the Open Geospatial Consortium WMS (Web Map Service) standard. The translator uses a set of URL parameters that mirror the WMS parameters as much as possible, and it also can generate a super overlay subdivision of any given area that is only loaded when needed, enabling very large areas of coverage at very high resolutions. It can make almost any dataset available as a WMS service visible and usable in any KML application, without the need to reformat the data.

  5. Hybrid overlay metrology for high order correction by using CDSEM

    Science.gov (United States)

    Leray, Philippe; Halder, Sandip; Lorusso, Gian; Baudemprez, Bart; Inoue, Osamu; Okagawa, Yutaka

    2016-03-01

    Overlay control has become one of the most critical issues for semiconductor manufacturing. Advanced lithographic scanners use high-order corrections or correction per exposure to reduce the residual overlay. It is not enough in traditional feedback of overlay measurement by using ADI wafer because overlay error depends on other process (etching process and film stress, etc.). It needs high accuracy overlay measurement by using AEI wafer. WIS (Wafer Induced Shift) is the main issue for optical overlay, IBO (Image Based Overlay) and DBO (Diffraction Based Overlay). We design dedicated SEM overlay targets for dual damascene process of N10 by i-ArF multi-patterning. The pattern is same as device-pattern locally. Optical overlay tools select segmented pattern to reduce the WIS. However segmentation has limit, especially the via-pattern, for keeping the sensitivity and accuracy. We evaluate difference between the viapattern and relaxed pitch gratings which are similar to optical overlay target at AEI. CDSEM can estimate asymmetry property of target from image of pattern edge. CDSEM can estimate asymmetry property of target from image of pattern edge. We will compare full map of SEM overlay to full map of optical overlay for high order correction ( correctables and residual fingerprints).

  6. How Concrete is Concrete?

    Directory of Open Access Journals (Sweden)

    Koeno Gravemeijer

    2011-01-01

    Full Text Available If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two different ways of making things concrete. Next another role of manipulatives, will be discussed, namely that of means for scaffolding and communication. In this role, manipulatives may function as means of support in a process that aims at helping students to build on their own thinking while constructing more sophisticated mathematics.Key words:  Conceret Learning Materials, School Math, Common Sense, Scaffolding, Communication DOI: http://dx.doi.org/10.22342/jme.2.1.780.1-14

  7. Colors, colored overlays, and reading skills

    Directory of Open Access Journals (Sweden)

    Arcangelo eUccula

    2014-07-01

    Full Text Available In this article, we are concerned with the role of colors in reading written texts. It has been argued that colored overlays applied above written texts positively influence both reading fluency and reading speed. These effects would be particularly evident for those individuals affected by the so called Meares-Irlen syndrome, i.e. who experience eyestrain and/or visual distortions – e.g. color, shape or movement illusions – while reading. This condition would interest the 12-14% of the general population and up to the 46% of the dyslexic population. Thus, colored overlays have been largely employed as a remedy for some aspects of the difficulties in reading experienced by dyslexic individuals, as fluency and speed. Despite the wide use of colored overlays, how they exert their effects has not been made clear yet. Also, according to some researchers, the results supporting the efficacy of colored overlays as a tool for helping readers are at least controversial. Furthermore, the very nature of the Meares-Irlen syndrome has been questioned. Here we provide a concise, critical review of the literature.

  8. Two-course bonded concrete bridge deck construction : condition and performance after six years.

    Science.gov (United States)

    1981-01-01

    This report presents the findings from a six-year study of two-course bonded concrete bridge decks constructed in Virginia. Each of three special portland cement concretes was applied as an overlay, or wearing course, on two experimental spans. The o...

  9. Pervious Concrete

    OpenAIRE

    Torsvik, Øyvind André Hoff

    2012-01-01

    Pervious concrete is a material with a high degree of permeability but generally low strength. The material is primarily used for paving applications but has shown promise in many other areas of usage. This thesis investigates the properties of pervious concrete using normal Norwegian aggregates and practices. An overview of important factors when it comes to designing and producing pervious concrete is the result of this investigation. Several experiments have been performed in the concrete ...

  10. Structural Precast Concrete Handbook

    DEFF Research Database (Denmark)

    Kjærbye, Per Oluf H

    Structural concept for precast concrete systems. Design og precast reinforced concrete components. Design of precast concrete connections. Illustrations on design of precast concrete buildings. Precast concrete assembly.......Structural concept for precast concrete systems. Design og precast reinforced concrete components. Design of precast concrete connections. Illustrations on design of precast concrete buildings. Precast concrete assembly....

  11. Engineered cementitious composites for strengthening masonry infilled reinforced concrete frames

    DEFF Research Database (Denmark)

    Dehghani, Ayoub; Nateghi-Alahi, Fariborz; Fischer, Gregor

    2015-01-01

    The results of the second part of a comprehensive experimental program, aimed at investigating the behavior of masonry infilled reinforced concrete (RC) frames strengthened with fiber reinforced engineered cementitious composites (ECC) used as an overlay on the masonry wall, are presented...

  12. Overlay Spectrum Sharing using Improper Gaussian Signaling

    KAUST Repository

    Amin, Osama

    2016-11-30

    Improper Gaussian signaling (IGS) scheme has been recently shown to provide performance improvements in interference limited networks as opposed to the conventional proper Gaussian signaling (PGS) scheme. In this paper, we implement the IGS scheme in overlay cognitive radio system, where the secondary transmitter broadcasts a mixture of two different signals. The first signal is selected from the PGS scheme to match the primary message transmission. On the other hand, the second signal is chosen to be from the IGS scheme in order to reduce the interference effect on the primary receiver. We then optimally design the overlay cognitive radio to maximize the secondary link achievable rate while satisfying the primary network quality of service requirements. In particular, we consider full and partial channel knowledge scenarios and derive the feasibility conditions of operating the overlay cognitive radio systems. Moreover, we derive the superiority conditions of the IGS schemes over the PGS schemes supported with closed form expressions for the corresponding power distribution and the circularity coefficient and parameters. Simulation results are provided to support our theoretical derivations.

  13. Achieving optimum diffraction based overlay performance

    Science.gov (United States)

    Leray, Philippe; Laidler, David; Cheng, Shaunee; Coogans, Martyn; Fuchs, Andreas; Ponomarenko, Mariya; van der Schaar, Maurits; Vanoppen, Peter

    2010-03-01

    Diffraction Based Overlay (DBO) metrology has been shown to have significantly reduced Total Measurement Uncertainty (TMU) compared to Image Based Overlay (IBO), primarily due to having no measurable Tool Induced Shift (TIS). However, the advantages of having no measurable TIS can be outweighed by increased susceptibility to WIS (Wafer Induced Shift) caused by target damage, process non-uniformities and variations. The path to optimum DBO performance lies in having well characterized metrology targets, which are insensitive to process non-uniformities and variations, in combination with optimized recipes which take advantage of advanced DBO designs. In this work we examine the impact of different degrees of process non-uniformity and target damage on DBO measurement gratings and study their impact on overlay measurement accuracy and precision. Multiple wavelength and dual polarization scatterometry are used to characterize the DBO design performance over the range of process variation. In conclusion, we describe the robustness of DBO metrology to target damage and show how to exploit the measurement capability of a multiple wavelength, dual polarization scatterometry tool to ensure the required measurement accuracy for current and future technology nodes.

  14. Glazed Concrete

    DEFF Research Database (Denmark)

    Bache, Anja Margrethe

    2010-01-01

    Why glazed concrete? Concrete hardens and finds its strength at room temperature whereas clay products must first be fired before they achieve this strength. They are stronger and three times as durable as clay products, which is a weighty reason for choosing concrete.5 Another reason, which....... If this succeeds, it will be possible to manufacture thin, large-scale glazed concrete panels comparable in size to concrete sandwich construction and larger which, with or without back-casting, can work as load-bearing construction elements....

  15. Concrete Hinges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2014-01-01

    In the first part of the 20th century concrete hinges developed by Freyssinet and Mesnager were widely tested and implemented in concrete structures. The concrete hinges were used a great deal in closed-spandrel arch bridges. Since such a bridge type has not been competitive for the past 40 years......, the research in concrete hinges has not evolved significantly in that period. But introducing a new state-of-the-art concrete arch bridge solution (Pearl-Chain arches invented at the Technical University of Denmark) creates a necessity of a concrete hinge research based on modern standards. Back when research...... in concrete hinges was more common different designs were proposed for the geometry and reinforcement. Previous research focused on fatigue, multi-axial stresses around the hinge throat, and the relation between rotation- and moment. But many different test-setups were proposed by different researchers...

  16. Concrete structures

    CERN Document Server

    Setareh, Mehdi

    2017-01-01

    This revised, fully updated second edition covers the analysis, design, and construction of reinforced concrete structures from a real-world perspective. It examines different reinforced concrete elements such as slabs, beams, columns, foundations, basement and retaining walls and pre-stressed concrete incorporating the most up-to-date edition of the American Concrete Institute Code (ACI 318-14) requirements for the design of concrete structures. It includes a chapter on metric system in reinforced concrete design and construction. A new chapter on the design of formworks has been added which is of great value to students in the construction engineering programs along with practicing engineers and architects. This second edition also includes a new appendix with color images illustrating various concrete construction practices, and well-designed buildings. The ACI 318-14 constitutes the most extensive reorganization of the code in the past 40 years. References to the various sections of the ACI 318-14 are pro...

  17. New low-viscosity overlay medium for viral plaque assays

    Directory of Open Access Journals (Sweden)

    Garten Wolfgang

    2006-08-01

    Full Text Available Abstract Background Plaque assays in cell culture monolayers under solid or semisolid overlay media are commonly used for quantification of viruses and antiviral substances. To overcome the pitfalls of known overlays, we tested suspensions of microcrystalline cellulose Avicel RC/CL™ as overlay media in the plaque and plaque-inhibition assay of influenza viruses. Results Significantly larger plaques were formed under Avicel-containing media, as compared to agar and methylcellulose (MC overlay media. The plaque size increased with decreasing Avicel concentration, but even very diluted Avicel overlays (0.3% ensured formation of localized plaques. Due to their low viscosity, Avicel overlays were easier to use than methylcellulose overlays, especially in the 96-well culture plates. Furthermore, Avicel overlay could be applied without prior removal of the virus inoculum thus facilitating the assay and reducing chances of cross-contamination. Using neuraminidase inhibitor oseltamivir carboxylate, we demonstrated applicability of the Avicel-based plaque reduction assay for testing of antiviral substances. Conclusion Plaque assay under Avicel-containing overlay media is easier, faster and more sensitive than assays under agar- and methylcellulose overlays. The assay can be readily performed in a 96-well plate format and seems particularly suitable for high-throughput virus titrations, serological studies and experiments on viral drug sensitivity. It may also facilitate work with highly pathogenic agents performed under hampered conditions of bio-safety labs.

  18. High-throughput electrical characterization for robust overlay lithography control

    Science.gov (United States)

    Devender, Devender; Shen, Xumin; Duggan, Mark; Singh, Sunil; Rullan, Jonathan; Choo, Jae; Mehta, Sohan; Tang, Teck Jung; Reidy, Sean; Holt, Jonathan; Kim, Hyung Woo; Fox, Robert; Sohn, D. K.

    2017-03-01

    Realizing sensitive, high throughput and robust overlay measurement is a challenge in current 14nm and advanced upcoming nodes with transition to 300mm and upcoming 450mm semiconductor manufacturing, where slight deviation in overlay has significant impact on reliability and yield1). Exponentially increasing number of critical masks in multi-patterning lithoetch, litho-etch (LELE) and subsequent LELELE semiconductor processes require even tighter overlay specification2). Here, we discuss limitations of current image- and diffraction- based overlay measurement techniques to meet these stringent processing requirements due to sensitivity, throughput and low contrast3). We demonstrate a new electrical measurement based technique where resistance is measured for a macro with intentional misalignment between two layers. Overlay is quantified by a parabolic fitting model to resistance where minima and inflection points are extracted to characterize overlay control and process window, respectively. Analyses using transmission electron microscopy show good correlation between actual overlay performance and overlay obtained from fitting. Additionally, excellent correlation of overlay from electrical measurements to existing image- and diffraction- based techniques is found. We also discuss challenges of integrating electrical measurement based approach in semiconductor manufacturing from Back End of Line (BEOL) perspective. Our findings open up a new pathway for accessing simultaneous overlay as well as process window and margins from a robust, high throughput and electrical measurement approach.

  19. SEM based overlay measurement between resist and buried patterns

    Science.gov (United States)

    Inoue, Osamu; Okagawa, Yutaka; Hasumi, Kazuhisa; Shao, Chuanyu; Leray, Philippe; Lorusso, Gian; Baudemprez, Bart

    2016-03-01

    With the continuous shrink in pattern size and increased density, overlay control has become one of the most critical issues in semiconductor manufacturing. Recently, SEM based overlay of AEI (After Etch Inspection) wafer has been used for reference and optimization of optical overlay (both Image Based Overlay (IBO) and Diffraction Based Overlay (DBO)). Overlay measurement at AEI stage contributes monitor and forecast the yield after formation by etch and calibrate optical measurement tools. however those overlay value seems difficult directly for feedback to a scanner. Therefore, there is a clear need to have SEM based overlay measurements of ADI (After Develop Inspection) wafers in order to serve as reference for optical overlay and make necessary corrections before wafers go to etch. Furthermore, to make the corrections as accurate as possible, actual device like feature dimensions need to be measured post ADI. This device size measurement is very unique feature of CDSEM , which can be measured with smaller area. This is currently possible only with the CD-SEM. This device size measurement is very unique feature of CD-SEM , which can be measured with smaller area. In this study, we assess SEM based overlay measurement of ADI and AEI wafer by using a sample from an N10 process flow. First, we demonstrate SEM based overlay performance at AEI by using dual damascene process for Via 0 (V0) and metal 1 (M1) layer. We also discuss the overlay measurements between litho-etch-litho stages of a triple patterned M1 layer and double pattern V0. Second, to illustrate the complexities in image acquisition and measurement we will measure overlay between M1B resist and buried M1A-Hard mask trench. Finally, we will show how high accelerating voltage can detect buried pattern information by BSE (Back Scattering Electron). In this paper we discuss the merits of this method versus standard optical metrology based corrections.

  20. Life extension of boilers using weld overlay protection

    Energy Technology Data Exchange (ETDEWEB)

    Lai, G.; Hulsizer, P. [Welding Services Inc., Norcross, GA (United States); Brooks, R. [Welding Services Inc., Welding Services Europe, Spijkenisse (Netherlands)

    1998-12-31

    The presentation describes the status of modern weld overlay technology for refurbishment, upgrading and life extension of boilers. The approaches to life extension of boilers include field overlay application, shop-fabricated panels for replacement of the worn, corroded waterwall and shop-fabricated overlay tubing for replacement of individual tubes in superheaters, generating banks and other areas. The characteristics of weld overlay products are briefly described. Also discussed are successful applications of various corrosion-resistant overlays for life extension of boiler tubes in waste-to-energy boilers, coal-fired boilers and chemical recovery boilers. Types of corrosion and selection of weld overlay alloys in these systems are also discussed. (orig.) 14 refs.

  1. Life extension of boilers using weld overlay protection

    Energy Technology Data Exchange (ETDEWEB)

    Lai, G; Hulsizer, P [Welding Services Inc., Norcross, GA (United States); Brooks, R [Welding Services Inc., Welding Services Europe, Spijkenisse (Netherlands)

    1999-12-31

    The presentation describes the status of modern weld overlay technology for refurbishment, upgrading and life extension of boilers. The approaches to life extension of boilers include field overlay application, shop-fabricated panels for replacement of the worn, corroded waterwall and shop-fabricated overlay tubing for replacement of individual tubes in superheaters, generating banks and other areas. The characteristics of weld overlay products are briefly described. Also discussed are successful applications of various corrosion-resistant overlays for life extension of boiler tubes in waste-to-energy boilers, coal-fired boilers and chemical recovery boilers. Types of corrosion and selection of weld overlay alloys in these systems are also discussed. (orig.) 14 refs.

  2. Overlay welding of FeCrAl alloys

    OpenAIRE

    Rashid, Lezan

    2016-01-01

    In this master thesis different overlay welding methods suitable for boiler application has been investigated. The purpose of this project is to define advantages and disadvantages for each overlay welding methods and suggest some evaluation criteria on some commercial and experimental alloys aimed for overlay welding material. Many components in a boiler are made of low alloy steel and the atmosphere in the furnace region can be very complex; therefore many different types of corrosion can o...

  3. Concrete Fibrations

    OpenAIRE

    Pagnan, Ruggero

    2017-01-01

    As far as we know, no notion of concrete fibration is available. We provide one such notion in adherence to the foundational attitude that characterizes the adoption of the fibrational perspective in approaching fundamental subjects in category theory and discuss it in connection with the notion of concrete category and the notions of locally small and small fibrations. We also discuss the appropriateness of our notion of concrete fibration for fibrations of small maps, which is relevant to a...

  4. Colors, colored overlays, and reading skills

    OpenAIRE

    Uccula, Arcangelo; Enna, Mauro; Mulatti, Claudio

    2014-01-01

    In this article, we are concerned with the role of colors in reading written texts. It has been argued that colored overlays applied above written texts positively influence both reading fluency and reading speed. These effects would be particularly evident for those individuals affected by the so called Meares-Irlen syndrome, i.e., who experience eyestrain and/or visual distortions – e.g., color, shape, or movement illusions – while reading. This condition would interest the 12–14% of the ge...

  5. The hilum overlay sign in a child

    Directory of Open Access Journals (Sweden)

    M J Van Wyk

    2010-12-01

    Full Text Available A 9-month-old girl presented with a 1-month history of coughing. A chest X-ray (CXR was performed, and the antero-posterior view demonstrated the hilum overlay sign. Furthermore, there was absence of the azygo-oesophageal line and bilateral paraspinal lines. The lateral CXR revealed a posterior mediastinal mass. Subsequently, a computed tomogram of the chest confirmed a posterior mediastinal mass, with calcifications and intraspinal extension consistent with neuroblastoma. Histological analysis confirmed this mass as a neuroblastoma.

  6. Reaching for the true overlay in advanced nodes

    Science.gov (United States)

    Koay, Chiew-seng; Hamieh, Bassem; Felix, Nelson; Gaudiello, John

    2017-03-01

    Traditionally, the total measurement uncertainty (TMU) of overlay metrology focuses on dynamic precision, toolinduced-shift, and matching, while rarely examining inaccuracy. However, some researchers have recently shown that measurement inaccuracy can still be large despite optimized small TMU. Moreover, this inaccuracy can consume a significant portion of the overlay budget in the advanced nodes. In addition to qualifying the overlay error of inline wafers, overlay metrology is also used for improving on-product overlay as it provides corrective feedback to the lithography scanner. The accuracy of the correction terms as a result depends directly upon the measurement accuracy. As such, enhanced overlay accuracy will improve the overlay performance of reworked wafers, or subsequently exposed wafers. We have previously shown that a segmented Blossom target is more prone to asymmetry-induced inaccuracy than a nonsegmented target is [1]. Since target segmentation is inevitable for SADP and SAQP patterning processes, their resulting overlay performance leaves a lot to be desired. In our quest to reach for the true overlay, this paper reports our investigations on accuracy enhancement techniques for image-based targets, such as redundancy and self-calibration, and on the use of simulation-optimized scatterometry-based targets.

  7. VT Data - Cons/Rec Overlay District 20110301, Winhall

    Data.gov (United States)

    Vermont Center for Geographic Information — Conservation and Recreatioal Protection overaly districts for the Town of Winhall, Vermont. Other overlay districts (Transfer of Development Rights, and Scenic...

  8. Overlay leaves litho: impact of non-litho processes on overlay and compensation

    Science.gov (United States)

    Ruhm, Matthias; Schulz, Bernd; Cotte, Eric; Seltmann, Rolf; Hertzsch, Tino

    2014-10-01

    According to the ITRS roadmap [1], the overlay requirement for the 28nm node is 8nm. If we compare this number with the performance given by tool vendors for their most advanced immersion systems (which is emerging. Mask contributions and so-called non-linear wafer distortions are known effects that can impact overlay quite significantly. Furthermore, it is often forgotten that downstream (post-litho) processes can impact the overlay as well. Thus, it can be required to compensate for the effects of subsequent processes already at the lithography operation. Within our paper, we will briefly touch on the wafer distortion topic and discuss the limitations of lithography compensation techniques such as higher order corrections versus solving the root cause of the distortions. The primary focus will be on the impact of the etch processes on the pattern placement error. We will show how individual layers can get affected differently by showing typical wafer signatures. However, in contrast to the above-mentioned wafer distortion topic, lithographic compensation techniques can be highly effective to reduce the placement error significantly towards acceptable levels (see Figure 1). Finally we will discuss the overall overlay budget for a 28nm contact to gate case by taking the impact of the individual process contributors into account.

  9. NANOMODIFIED CONCRETE

    Directory of Open Access Journals (Sweden)

    B. M. Khroustalev

    2015-01-01

    Full Text Available One of the main directions in construction material science is the development of  next generation concrete that is ultra-dense, high-strength, ultra-porous, high heat efficient, extra corrosion-resistant. Selection of such direction is caused by extreme operational impacts on the concrete, namely: continuously increasing load on the concrete and various dynamics of such loads; the necessity in operation of concrete products in a wide temperature range and their exposure to various chemical and physical effects.The next generation concrete represents high-tech concrete mixtures with additives that takes on and retain the required properties when hardening and being used under any operational conditions. A differential characteristic of the next generation concrete is its complexity that presumes usage of various mineral dispersed components, two- and three fractional fine and coarse aggregates, complex chemical additives, combinations of polymer and iron reinforcement.Design strength and performance properties level of the next generation concrete is achieved by high-quality selection of the composition, proper selection of manufacturing techniques, concrete curing, bringing the quality of concrete items to the required level of technical condition during the operational phase. However, directed formation of its structure is necessary in order to obtain high-tech concrete.Along with the traditional methods for regulation of the next generation concrete structure, modification of concrete while using silica nanoparticles is also considered as a perspective one because the concrete patterning occurs due to introduction of a binder in a mineral matrix. Due to this it is possible to obtain nano-modified materials with completely new properties.The main problem with the creation of nano-modified concrete is a uniform distribution of nano-materials in the volume of the cement matrix which is particularly important in the cases of adding a modifier in

  10. Investigation of Iron Aluminide Weld Overlays

    Energy Technology Data Exchange (ETDEWEB)

    Banovic, S.W.; DuPont, J.B.; Levin, B.F.; Marder, A.R.

    1999-08-02

    Conventional fossil fired boilers have been retrofitted with low NO(sub)x burners in order for the power plants to comply with new clean air regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion typically has been enhanced resulting in premature tube failure. To protect the existing panels from accelerated attack, weld overlay coatings are typically being applied. By depositing an alloy that offers better corrosion resistance than the underlying tube material, the wastage rates can be reduced. While Ni-based and stainless steel compositions are presently providing protection, they are expensive and susceptible to failure via corrosion-fatigue due to microsegregation upon solidification. Another material system presently under consideration for use as a coating in the oxidation/sulfidation environments is iron-aluminum. These alloys are relatively inexpensive, exhibit little microsegregation, and show excellent corrosion resistance. However, their use is limited due to weldability issues and their lack of corrosion characterization in simulated low NO(sub)x gas compositions. Therefore a program was initiated in 1996 to evaluate the use of iron-aluminum weld overlay coatings for erosion/corrosion protection of boiler tubes in fossil fired boilers with low NO(sub)x burners. Investigated properties included weldability, corrosion behavior, erosion resistance, and erosion-corrosion performance.

  11. Real cell overlay measurement through design based metrology

    Science.gov (United States)

    Yoo, Gyun; Kim, Jungchan; Park, Chanha; Lee, Taehyeong; Ji, Sunkeun; Jo, Gyoyeon; Yang, Hyunjo; Yim, Donggyu; Yamamoto, Masahiro; Maruyama, Kotaro; Park, Byungjun

    2014-04-01

    Until recent device nodes, lithography has been struggling to improve its resolution limit. Even though next generation lithography technology is now facing various difficulties, several innovative resolution enhancement technologies, based on 193nm wavelength, were introduced and implemented to keep the trend of device scaling. Scanner makers keep developing state-of-the-art exposure system which guarantees higher productivity and meets a more aggressive overlay specification. "The scaling reduction of the overlay error has been a simple matter of the capability of exposure tools. However, it is clear that the scanner contributions may no longer be the majority component in total overlay performance. The ability to control correctable overlay components is paramount to achieve the desired performance.(2)" In a manufacturing fab, the overlay error, determined by a conventional overlay measurement: by using an overlay mark based on IBO and DBO, often does not represent the physical placement error in the cell area of a memory device. The mismatch may arise from the size or pitch difference between the overlay mark and the cell pattern. Pattern distortion, caused by etching or CMP, also can be a source of the mismatch. Therefore, the requirement of a direct overlay measurement in the cell pattern gradually increases in the manufacturing field, and also in the development level. In order to overcome the mismatch between conventional overlay measurement and the real placement error of layer to layer in the cell area of a memory device, we suggest an alternative overlay measurement method utilizing by design, based metrology tool. A basic concept of this method is shown in figure1. A CD-SEM measurement of the overlay error between layer 1 and 2 could be the ideal method but it takes too long time to extract a lot of data from wafer level. An E-beam based DBM tool provides high speed to cover the whole wafer with high repeatability. It is enabled by using the design as a

  12. Hybrid overlay metrology with CDSEM in a BEOL patterning scheme

    Science.gov (United States)

    Leray, Philippe; Jehoul, Christiane; Inoue, Osamu; Okagawa, Yutaka

    2015-03-01

    Overlay metrology accuracy is a major concern for our industry. Advanced logic process require more tighter overlay control for multipatterning schemes. TIS (Tool Induced Shift) and WIS (Wafer Induced Shift) are the main issues for IBO (Image Based Overlay) and DBO (Diffraction Based Overlay). Methods of compensation have been introduced, some are even very efficient to reduce these measured offsets. Another related question is about the overlay target designs. These targets are never fully representative of the design rules, strong efforts have been achieved, but the device cannot be completely duplicated. Ideally, we would like to measure in the device itself to verify the real overlay value. Top down CDSEM can measure critical dimensions of any structure, it is not dependent of specific target design. It can also measure the overlay errors but only in specific cases like LELE (Litho Etch Litho Etch) after final patterning. In this paper, we will revisit the capability of the CDSEM at final patterning by measuring overlay in dedicated targets as well as inside a logic and an SRAM design. In the dedicated overlay targets, we study the measurement differences between design rules gratings and relaxed pitch gratings. These relaxed pitch which are usually used in IBO or DBO targets. Beyond this "simple" LELE case, we will explore the capability of the CDSEM to measure overlay even if not at final patterning, at litho level. We will assess the hybridization of DBO and CDSEM for reference to optical tools after final patterning. We will show that these reference data can be used to validate the DBO overlay results (correctables and residual fingerprints).

  13. Strategic intelligence on emerging technologies: Scientometric overlay mapping

    NARCIS (Netherlands)

    Rotolo, D.; Rafols, I.; Hopkins, M.M.; Leydesdorff, L.

    This paper examines the use of scientometric overlay mapping as a tool of “strategic intelligence” to aid the governing of emerging technologies. We develop an integrative synthesis of different overlay mapping techniques and associated perspectives on technological emergence across geographical,

  14. Multi-level Reconfigurable Self-organization in Overlay Services

    NARCIS (Netherlands)

    Pournaras, E.

    2013-01-01

    Large-scale decentralized systems organized in overlay networks are complex to manage. Such systems integrate organizational complexity in the application-level resulting in low abstraction and modularity in their services. This thesis introduces a multi-level conceptual architecture for overlay

  15. Diffraction-based overlay metrology for double patterning technologies

    Science.gov (United States)

    Dasari, Prasad; Korlahalli, Rahul; Li, Jie; Smith, Nigel; Kritsun, Oleg; Volkman, Cathy

    2009-03-01

    The extension of optical lithography to 32nm and beyond is made possible by Double Patterning Techniques (DPT) at critical levels of the process flow. The ease of DPT implementation is hindered by increased significance of critical dimension uniformity and overlay errors. Diffraction-based overlay (DBO) has shown to be an effective metrology solution for accurate determination of the overlay errors associated with double patterning [1, 2] processes. In this paper we will report its use in litho-freeze-litho-etch (LFLE) and spacer double patterning technology (SDPT), which are pitch splitting solutions that reduce the significance of overlay errors. Since the control of overlay between various mask/level combinations is critical for fabrication, precise and accurate assessment of errors by advanced metrology techniques such as spectroscopic diffraction based overlay (DBO) and traditional image-based overlay (IBO) using advanced target designs will be reported. A comparison between DBO, IBO and CD-SEM measurements will be reported. . A discussion of TMU requirements for 32nm technology and TMU performance data of LFLE and SDPT targets by different overlay approaches will be presented.

  16. BASIC overlay for CAMAC data and command handling

    Energy Technology Data Exchange (ETDEWEB)

    Ciftcioglu, O [Istanbul Technical Univ. (Turkey). Inst. for Nuclear Energy

    1979-11-15

    A BASIC overlay has been developed for the BASIC language run in the PDP-11 series of computers. The overlay has particularly been wirtten for a dedicated Camac Crate Controller DC-011 from Ortec. By means of the overlay, any command comprising C, N, A, F information can easily be issued by the host system to communicate with the peripherals connected to the CAMAC system, through the CAMAC interface. The overlay is particularly useful for rather slow control systems and data handling between two different operating systems with incompatible formats for the data files having the CAMAC system as a mutual system component controllable by each of the operating systems individually. The overlay can easily be modified to be used for a Standard controller (type A-1) or any other type of dedicated controller.

  17. Accuracy optimization with wavelength tunability in overlay imaging technology

    Science.gov (United States)

    Lee, Honggoo; Kang, Yoonshik; Han, Sangjoon; Shim, Kyuchan; Hong, Minhyung; Kim, Seungyoung; Lee, Jieun; Lee, Dongyoung; Oh, Eungryong; Choi, Ahlin; Kim, Youngsik; Marciano, Tal; Klein, Dana; Hajaj, Eitan M.; Aharon, Sharon; Ben-Dov, Guy; Lilach, Saltoun; Serero, Dan; Golotsvan, Anna

    2018-03-01

    As semiconductor manufacturing technology progresses and the dimensions of integrated circuit elements shrink, overlay budget is accordingly being reduced. Overlay budget closely approaches the scale of measurement inaccuracies due to both optical imperfections of the measurement system and the interaction of light with geometrical asymmetries of the measured targets. Measurement inaccuracies can no longer be ignored due to their significant effect on the resulting device yield. In this paper we investigate a new approach for imaging based overlay (IBO) measurements by optimizing accuracy rather than contrast precision, including its effect over the total target performance, using wavelength tunable overlay imaging metrology. We present new accuracy metrics based on theoretical development and present their quality in identifying the measurement accuracy when compared to CD-SEM overlay measurements. The paper presents the theoretical considerations and simulation work, as well as measurement data, for which tunability combined with the new accuracy metrics is shown to improve accuracy performance.

  18. Ablative overlays for Space Shuttle leading edge ascent heat protection

    Science.gov (United States)

    Strauss, E. L.

    1975-01-01

    Ablative overlays were evaluated via a plasma-arc simulation of the ascent pulse on the leading edge of the Space Shuttle Orbiter. Overlay concepts included corkboard, polyisocyanurate foam, low-density Teflon, epoxy, and subliming salts. Their densities ranged from 4.9 to 81 lb per cu ft, and the thicknesses varied from 0.107 to 0.330 in. Swept-leading-edge models were fabricated from 30-lb per cu ft silicone-based ablators. The overlays were bonded to maintain the surface temperature of the base ablator below 500 F during ascent. Foams provided minimum-weight overlays, and subliming salts provided minimum-thickness overlays. Teflon left the most uniform surface after ascent heating.

  19. Concrete domains

    OpenAIRE

    Kahn, G.; Plotkin, G.D.

    1993-01-01

    This paper introduces the theory of a particular kind of computation domains called concrete domains. The purpose of this theory is to find a satisfactory framework for the notions of coroutine computation and sequentiality of evaluation.

  20. Photocatalyticpaving concrete

    OpenAIRE

    Lyapidevskaya Ol'ga Borisovna; Fraynt Mikhail Aleksandrovich

    2014-01-01

    Today bituminous concrete is a conventional paving material. Among its advantages one can name dustlessness and noiselessness, fine wear (up to 1 mm a year) and fine maintainability. As the main disadvantages of this material one can name high slipperiness under humidification, low durability and weather resistance. Besides that, during placement of the bituminous concrete a lot of different air pollutants are emitted, which are harmful for environment and human’s health (they are listed in t...

  1. Photocatalyticpaving concrete

    Directory of Open Access Journals (Sweden)

    Lyapidevskaya Ol'ga Borisovna

    2014-02-01

    Full Text Available Today bituminous concrete is a conventional paving material. Among its advantages one can name dustlessness and noiselessness, fine wear (up to 1 mm a year and fine maintainability. As the main disadvantages of this material one can name high slipperiness under humidification, low durability and weather resistance. Besides that, during placement of the bituminous concrete a lot of different air pollutants are emitted, which are harmful for environment and human’s health (they are listed in the paper according to the US Environmental Protection Agency materials. As an alternative, one can use cement-concrete pavement, which is in many ways more efficient than the bituminous concrete. It is proposed to enhance environmental performance of the cement-concrete pavement via usage of photocatalysis. The mechanism of different photocatalytic reactions is described in the paper, namely heterogeneous and homogeneous photocatalysis, photo-induces, photoactivated catalysis and catalytical photoreactions. It is pro-posed to use heterogeneous photocatalysis with titanium dioxide as a photocatalyst. The mechanism of photo oxidation of air contaminants, with the usage of titanium dioxide is2described. The paper sets problems, connected with the sensibilization of TiOto thevisible light (it is proposed to use titanium dioxide, doped with the atoms of certain elements to increase its sensibility to the visible light and with the development of a new photocatalytic paving concrete, which will meet the requirements, specified for paving in the climatic and traffic conditions of the Russian Federation.

  2. In-cell overlay metrology by using optical metrology tool

    Science.gov (United States)

    Lee, Honggoo; Han, Sangjun; Hong, Minhyung; Kim, Seungyoung; Lee, Jieun; Lee, DongYoung; Oh, Eungryong; Choi, Ahlin; Park, Hyowon; Liang, Waley; Choi, DongSub; Kim, Nakyoon; Lee, Jeongpyo; Pandev, Stilian; Jeon, Sanghuck; Robinson, John C.

    2018-03-01

    Overlay is one of the most critical process control steps of semiconductor manufacturing technology. A typical advanced scheme includes an overlay feedback loop based on after litho optical imaging overlay metrology on scribeline targets. The after litho control loop typically involves high frequency sampling: every lot or nearly every lot. An after etch overlay metrology step is often included, at a lower sampling frequency, in order to characterize and compensate for bias. The after etch metrology step often involves CD-SEM metrology, in this case in-cell and ondevice. This work explores an alternative approach using spectroscopic ellipsometry (SE) metrology and a machine learning analysis technique. Advanced 1x nm DRAM wafers were prepared, including both nominal (POR) wafers with mean overlay offsets, as well as DOE wafers with intentional across wafer overlay modulation. After litho metrology was measured using optical imaging metrology, as well as after etch metrology using both SE and CD-SEM for comparison. We investigate 2 types of machine learning techniques with SE data: model-less and model-based, showing excellent performance for after etch in-cell on-device overlay metrology.

  3. Self-Placing Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Certain concrete pours have areas where the congestion of reinforcing bars make placement of concrete almost impossible. Using conventional placing and vibration techniques, the resulting concrete can have considerable honeycombing due to the development of voids. Self-placing concrete is a possible solution to the problem. Also known as self-compactable concrete, self-consolidating concrete, flowable concrete, and non-vibration concrete. These concretes eliminate the need for vibration in a ...

  4. Advanced diffraction-based overlay for double patterning

    Science.gov (United States)

    Li, Jie; Liu, Yongdong; Dasari, Prasad; Hu, Jiangtao; Smith, Nigel; Kritsun, Oleg; Volkman, Catherine

    2010-03-01

    Diffraction based overlay (DBO) technologies have been developed to address the tighter overlay control challenges as the dimensions of integrated circuit continue to shrink. Several studies published recently have demonstrated that the performance of DBO technologies has the potential to meet the overlay metrology budget for 22nm technology node. However, several hurdles must be cleared before DBO can be used in production. One of the major hurdles is that most DBO technologies require specially designed targets that consist of multiple measurement pads, which consume too much space and increase measurement time. A more advanced spectroscopic ellipsometry (SE) technology-Mueller Matrix SE (MM-SE) is developed to address the challenge. We use a double patterning sample to demonstrate the potential of MM-SE as a DBO candidate. Sample matrix (the matrix that describes the effects of the sample on the incident optical beam) obtained from MM-SE contains up to 16 elements. We show that the Mueller elements from the off-diagonal 2x2 blocks respond to overlay linearly and are zero when overlay errors are absent. This superior property enables empirical DBO (eDBO) using two pads per direction. Furthermore, the rich information in Mueller matrix and its direct response to overlay make it feasible to extract overlay errors from only one pad per direction using modeling approach (mDBO). We here present the Mueller overlay results using both eDBO and mDBO and compare the results with image-based overlay (IBO) and CD-SEM results. We also report the tool induced shifts (TIS) and dynamic repeatability.

  5. Electronic structure of metal overlayers on rhodium

    International Nuclear Information System (INIS)

    Feibelman, P.J.; Hamann, D.R.

    1983-01-01

    We have evaluated work functions, surface core-level shifts, and surface band dispersions for clean, Ag-covered, and Pd-covered Rh(100) surfaces, and for clean and Ag-covered Rh(111). The calculations were performed self-consistently, using the surface-linearized augmented-plane-wave method. As expected from the Pauling electronegativities, Ag adsorption lowers the work function from the clean Rh value, by several tenths of an eV, while Pd has an almost negligible effect. The values calculated for the core-level shifts of various films are shown to correspond to expectations based on surface band narrowing and layerwise charge neutrality. Using the core-level shifts, we predict heat-of-adsorption differences (for Ag on Pd vs Ag on Rh, etc.) that are in quite good agreement with the empirical predictions of Miedema and Dorleijn. Finally, the chemical inactivity of the Ag-covered Rh surface is associated with the fact that, for that system, the outer-layer local density of states is essentially that of Ag, with a characteristically low value at the Fermi energy. On the other hand, the Pd-covered Rh surface should behave much like clean Rh with an extra electron per surface atom. The surface band dispersions for the Pd-covered and clean Rh surfaces are closely similar. This result contrasts sharply with the case of Pd-covered Nb, for which, because of the appreciable electronegativity difference, the Pd overlayer is effectively ''noble.''

  6. Weld overlay cladding with iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, G.M. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    The author has established a range of compositions for these alloys within which hot cracking resistance is very good, and within which cold cracking can be avoided in many instances by careful control of welding conditions, particularly preheat and postweld heat treatment. For example, crack-free butt welds have been produced for the first time in 12-mm thick wrought Fe{sub 3}Al plate. Cold cracking, however, still remains an issue in many cases. The author has developed a commercial source for composite weld filler metals spanning a wide range of achievable aluminum levels, and are pursuing the application of these filler metals in a variety of industrial environments. Welding techniques have been developed for both the gas tungsten arc and gas metal arc processes, and preliminary work has been done to utilize the wire arc process for coating of boiler tubes. Clad specimens have been prepared for environmental testing in-house, and a number of components have been modified and placed in service in operating kraft recovery boilers. In collaboration with a commercial producer of spiral weld overlay tubing, the author is attempting to utilize the new filler metals for this novel application.

  7. Improving Overlay in Nanolithography with a Deformable Mask Holder

    National Research Council Canada - National Science Library

    Harriott, L. R

    2004-01-01

    In very fine-line VLSI photolithography, alignment and overlay errors due to distortion in the projected image of a photomask relative to an existing pattern on a silicon wafer are becoming such serious problems...

  8. Opportunistic transmitter selection for selfless overlay cognitive radios

    KAUST Repository

    Shaqfeh, Mohammad; Zafar, Ammar; Alnuweiri, Hussein M.; Alouini, Mohamed-Slim

    2013-01-01

    We propose an opportunistic strategy to grant channel access to the primary and secondary transmitters in causal selfless overlay cognitive radios over block-fading channels. The secondary transmitter helps the primary transmitter by relaying

  9. Wafer edge overlay control solution for N7 and beyond

    Science.gov (United States)

    van Haren, Richard; Calado, Victor; van Dijk, Leon; Hermans, Jan; Kumar, Kaushik; Yamashita, Fumiko

    2018-03-01

    Historically, the on-product overlay performance close to the wafer edge is lagging with respect to the inner part of the wafer. The reason for this is that wafer processing is less controlled close to the wafer edge as opposed to the rest of the wafer. It is generally accepted that Chemical Vapor Deposition (CVD) of stressed layers that cause wafer warp, wafer table contamination, Chemical Mechanical Polishing (CMP), and Reactive Ion Etch (RIE) may deteriorate the overlay performance and/or registration close to the wafer edge. For the N7 technology node and beyond, it is anticipated that the tight on-product overlay specification is required across the full wafer which includes the edge region. In this work, we highlight one contributor that may negatively impact the on-product overlay performance, namely the etch step. The focus will be mainly on the wafer edge region but the remaining part of the wafer is considered as well. Three use-cases are examined: multiple Litho-Etch steps (LEn), contact hole layer etch, and the copper dual damascene etch. We characterize the etch contribution by considering the overlay measurement after resist development inspect (ADI) and after etch inspect (AEI). We show that the Yieldstar diffraction based overlay (μDBO) measurements can be utilized to characterize the etch contribution to the overlay budget. The effects of target asymmetry as well as overlay shifts are considered and compared with SEM measurements. Based on the results above, we propose a control solution aiming to reduce or even eliminate the delta between ADI and AEI. By doing so, target/mark to device offsets due to etch might be avoided.

  10. 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...

  11. Historic Concrete : From Concrete Repair to Concrete Conservation

    NARCIS (Netherlands)

    Heinemann, H.A.

    2013-01-01

    Concrete like materials were already applied during the Roman Empire. After the decline of the Roman Empire, a wide scale application of concrete only reappeared in the 19th century. Here lies also the origin of modern (reinforced) concrete. Since then, both concrete application and composition have

  12. Overlay improvements using a real time machine learning algorithm

    Science.gov (United States)

    Schmitt-Weaver, Emil; Kubis, Michael; Henke, Wolfgang; Slotboom, Daan; Hoogenboom, Tom; Mulkens, Jan; Coogans, Martyn; ten Berge, Peter; Verkleij, Dick; van de Mast, Frank

    2014-04-01

    While semiconductor manufacturing is moving towards the 14nm node using immersion lithography, the overlay requirements are tightened to below 5nm. Next to improvements in the immersion scanner platform, enhancements in the overlay optimization and process control are needed to enable these low overlay numbers. Whereas conventional overlay control methods address wafer and lot variation autonomously with wafer pre exposure alignment metrology and post exposure overlay metrology, we see a need to reduce these variations by correlating more of the TWINSCAN system's sensor data directly to the post exposure YieldStar metrology in time. In this paper we will present the results of a study on applying a real time control algorithm based on machine learning technology. Machine learning methods use context and TWINSCAN system sensor data paired with post exposure YieldStar metrology to recognize generic behavior and train the control system to anticipate on this generic behavior. Specific for this study, the data concerns immersion scanner context, sensor data and on-wafer measured overlay data. By making the link between the scanner data and the wafer data we are able to establish a real time relationship. The result is an inline controller that accounts for small changes in scanner hardware performance in time while picking up subtle lot to lot and wafer to wafer deviations introduced by wafer processing.

  13. Performance of ASML YieldStar μDBO overlay targets for advanced lithography nodes C028 and C014 overlay process control

    Science.gov (United States)

    Blancquaert, Yoann; Dezauzier, Christophe; Depre, Jerome; Miqyass, Mohamed; Beltman, Jan

    2013-04-01

    Continued tightening of overlay control budget in semiconductor lithography drives the need for improved metrology capabilities. Aggressive improvements are needed for overlay metrology speed, accuracy and precision. This paper is dealing with the on product metrology results of a scatterometry based platform showing excellent production results on resolution, precision, and tool matching for overlay. We will demonstrate point to point matching between tool generations as well as between target sizes and types. Nowadays, for the advanced process nodes a lot of information is needed (Higher order process correction, Reticle fingerprint, wafer edge effects) to quantify process overlay. For that purpose various overlay sampling schemes are evaluated: ultra- dense, dense and production type. We will show DBO results from multiple target type and shape for on product overlay control for current and future node down to at least 14 nm node. As overlay requirements drive metrology needs, we will evaluate if the new metrology platform meets the overlay requirements.

  14. Interplanetary Overlay Network Bundle Protocol Implementation

    Science.gov (United States)

    Burleigh, Scott C.

    2011-01-01

    The Interplanetary Overlay Network (ION) system's BP package, an implementation of the Delay-Tolerant Networking (DTN) Bundle Protocol (BP) and supporting services, has been specifically designed to be suitable for use on deep-space robotic vehicles. Although the ION BP implementation is unique in its use of zero-copy objects for high performance, and in its use of resource-sensitive rate control, it is fully interoperable with other implementations of the BP specification (Internet RFC 5050). The ION BP implementation is built using the same software infrastructure that underlies the implementation of the CCSDS (Consultative Committee for Space Data Systems) File Delivery Protocol (CFDP) built into the flight software of Deep Impact. It is designed to minimize resource consumption, while maximizing operational robustness. For example, no dynamic allocation of system memory is required. Like all the other ION packages, ION's BP implementation is designed to port readily between Linux and Solaris (for easy development and for ground system operations) and VxWorks (for flight systems operations). The exact same source code is exercised in both environments. Initially included in the ION BP implementations are the following: libraries of functions used in constructing bundle forwarders and convergence-layer (CL) input and output adapters; a simple prototype bundle forwarder and associated CL adapters designed to run over an IPbased local area network; administrative tools for managing a simple DTN infrastructure built from these components; a background daemon process that silently destroys bundles whose time-to-live intervals have expired; a library of functions exposed to applications, enabling them to issue and receive data encapsulated in DTN bundles; and some simple applications that can be used for system checkout and benchmarking.

  15. High Performance Concrete

    Directory of Open Access Journals (Sweden)

    Traian Oneţ

    2009-01-01

    Full Text Available The paper presents the last studies and researches accomplished in Cluj-Napoca related to high performance concrete, high strength concrete and self compacting concrete. The purpose of this paper is to raid upon the advantages and inconveniences when a particular concrete type is used. Two concrete recipes are presented, namely for the concrete used in rigid pavement for roads and another one for self-compacting concrete.

  16. Concrete spirituality

    OpenAIRE

    Kritzinger, Johannes N.J.

    2014-01-01

    This article reflects on a number of liturgical innovations in the worship of Melodi ya Tshwane, an inner-city congregation of the Uniting Reformed Church in Southern Africa (URCSA). The focus of the innovations was to implement the understanding of justice in Article 4 of the Confession of Belhar, a confessional standard of the URCSA. The basic contention of the article is that well designed liturgies that facilitate experiences of beauty can nurture a concrete spirituality to mobilise urba...

  17. Location-Aware Cross-Layer Design Using Overlay Watermarks

    Directory of Open Access Journals (Sweden)

    Paul Ho

    2007-04-01

    Full Text Available A new orthogonal frequency division multiplexing (OFDM system embedded with overlay watermarks for location-aware cross-layer design is proposed in this paper. One major advantage of the proposed system is the multiple functionalities the overlay watermark provides, which includes a cross-layer signaling interface, a transceiver identification for position-aware routing, as well as its basic role as a training sequence for channel estimation. Wireless terminals are typically battery powered and have limited wireless communication bandwidth. Therefore, efficient collaborative signal processing algorithms that consume less energy for computation and less bandwidth for communication are needed. Transceiver aware of its location can also improve the routing efficiency by selective flooding or selective forwarding data only in the desired direction, since in most cases the location of a wireless host is unknown. In the proposed OFDM system, location information of a mobile for efficient routing can be easily derived when a unique watermark is associated with each individual transceiver. In addition, cross-layer signaling and other interlayer interactive information can be exchanged with a new data pipe created by modulating the overlay watermarks. We also study the channel estimation and watermark removal techniques at the physical layer for the proposed overlay OFDM. Our channel estimator iteratively estimates the channel impulse response and the combined signal vector from the overlay OFDM signal. Cross-layer design that leads to low-power consumption and more efficient routing is investigated.

  18. Electronic structure of uranium overlayers on magnesium and aluminium

    Science.gov (United States)

    Gouder, T.

    1997-06-01

    We studied U overlayers on polycrystalline Mg and Al by X-ray and ultra-violet photoelectron spectroscopies (XPS and UPS, respectively), and compared the mode of growth and the evolution of the electronic structure as a function of coverage. The goal of this work was to detect localization, or at least correlation effects, in U overlayers and U substrate near surface alloys, which were expected to occur because of the reduced U 5f bandwidth in these systems. On Mg, U deposits as a pure overlayer without any interdiffusion, while on Al spontaneous interdiffusion takes place. The U 4f spectra of {U}/{Mg} show only weak correlation satellites. Nevertheless, the asymmetrical shape of the U 4f peak indicates 5f band narrowing. On Al, strong correlation satellites are observed in addition to plasmon loss features. It seems that U-substrate interactions promote correlation effects, while the reduced coordination in overlayers plays a less important role. UPS valence-band (VB) spectra of the two systems look remarkably similar. They do not show any correlation satellites. With decreasing overlayer thickness the 5f peak narrows, which is attributed to 5f band narrowing at the surface.

  19. Ground penetrating radar utilization in exploring inadequate concrete covers in a new bridge deck

    Directory of Open Access Journals (Sweden)

    Md. Istiaque Hasan

    2014-01-01

    Full Text Available The reinforced concrete cast in place four span deck of a concrete bridge near Roanoke, Texas, was recently completed. Due to possible construction errors, it was suspected that the concrete covers in the deck did not conform to drawings and specifications. A full scale non-destructive evaluation of the concrete covers was carried out using ground penetrating radar (GPR equipment. Cover values were determined from the radargram generated from the scan. The estimated covers were plotted on contour maps. Migration data can substitute the drilling based ground truth data without compromising the concrete cover estimations, except for areas with very high cover values. Areas with high water content may result in inaccurate concrete dielectric constants. Based on the results, significant retrofitting of the bridge deck, such as additional overlay, was recommended.

  20. High-volume manufacturing device overlay process control

    Science.gov (United States)

    Lee, Honggoo; Han, Sangjun; Woo, Jaeson; Lee, DongYoung; Song, ChangRock; Heo, Hoyoung; Brinster, Irina; Choi, DongSub; Robinson, John C.

    2017-03-01

    Overlay control based on DI metrology of optical targets has been the primary basis for run-to-run process control for many years. In previous work we described a scenario where optical overlay metrology is performed on metrology targets on a high frequency basis including every lot (or most lots) at DI. SEM based FI metrology is performed ondevice in-die as-etched on an infrequent basis. Hybrid control schemes of this type have been in use for many process nodes. What is new is the relative size of the NZO as compared to the overlay spec, and the need to find more comprehensive solutions to characterize and control the size and variability of NZO at the 1x nm node: sampling, modeling, temporal frequency and control aspects, as well as trade-offs between SEM throughput and accuracy.

  1. Rubblization and base overlay of FM 912 and FM 1155.

    Science.gov (United States)

    2010-01-01

    In many instances rubblization may be a good option to convert a deteriorated concrete pavement into a : flexible pavement structure. In this project, the Texas Department of Transportation conducted rubblization : on portions of a concrete pavement ...

  2. OVERLAY DENTURES: A REVIEW AND REPORT OF FOUR CASES

    Directory of Open Access Journals (Sweden)

    Deeksha SHARMA

    2013-12-01

    Full Text Available Patients with ectodermal dysplasia or having under‑ gone cleft surgery with anodontia or hypodontia, hypo‑ plastic conical teeth and patients with severely worn dentition are difficult to treat because of the poor remaining tooth structure. These patients often exhibit loss of vertical dimension of occlusion and aesthetic problems and usually need complex prosthetic treatments. Financial constraints or other priorities often restrict one from choosing the most desirable treatment. The overlay removable denture is a covering prosthesis partially supported by natural teeth, tooth roots, or dental implants, providing an efficient alter‑ native of treatment. Clinical reports describe the various applications of overlay dentures.

  3. Solidification paths in modified Inconel 625 weld overlay material

    DEFF Research Database (Denmark)

    Chandrasekaran, Karthik; Tiedje, Niels Skat; Hald, John

    2009-01-01

    Inconel 625 is commonly used for overlay welding to protect the base metal against high temperature corrosion. The efficiency of corrosion protection depends on effective mixing of the overlay weld with the base metal and the subsequent segregation of alloy elements during solidification....... Metallographic analysis of solidified samples of Inconel 625 with addition of selected elements is compared with thermodynamic modelling of segregation during solidification. The influence of changes in the melt chemistry on the formation of intermetallic phases during solidification is shown. In particular...

  4. Measured residual stresses in overlay pipe weldments removed from service

    International Nuclear Information System (INIS)

    Shack, W.J.

    1985-02-01

    Surface and throughwall residual stresses were measured on an elbow-to-pipe weldment that had been removed from the Hatch-2 reactor about a year after the application of a weld overlay. The results were compared with experimental measurements on three mock-up weldments and with finite-element calculations. The comparison shows that there are significant differences in the form and magnitude of the residual stress distributions. However, even after more than a year of service, the residual stresses over most of the inner surface of the actual plant weldment with an overlay were strongly compressive. 3 refs., 7 figs

  5. Combination of Bayesian Network and Overlay Model in User Modeling

    Directory of Open Access Journals (Sweden)

    Loc Nguyen

    2009-12-01

    Full Text Available The core of adaptive system is user model containing personal information such as knowledge, learning styles, goals… which is requisite for learning personalized process. There are many modeling approaches, for example: stereotype, overlay, plan recognition… but they don’t bring out the solid method for reasoning from user model. This paper introduces the statistical method that combines Bayesian network and overlay modeling so that it is able to infer user’s knowledge from evidences collected during user’s learning process.

  6. Diffraction-based overlay for spacer patterning and double patterning technology

    Science.gov (United States)

    Lee, Byoung Hoon; Park, JeongSu; Lee, Jongsu; Park, Sarohan; Lim, ChangMoon; Yim, Dong-Gyu; Park, Sungki; Ryu, Chan-Ho; Morgan, Stephen; van de Schaar, Maurits; Fuchs, Andreas; Bhattacharyya, Kaustuve

    2011-03-01

    Overlay performance will be increasingly important for Spacer Patterning Technology (SPT) and Double Patterning Technology (DPT) as various Resolution Enhancement Techniques are employed to extend the resolution limits of lithography. Continuous shrinkage of devices makes overlay accuracy one of the most critical issues while overlay performance is completely dependent on exposure tool. Image Based Overlay (IBO) has been used as the mainstream metrology for overlay by the main memory IC companies, but IBO is not suitable for some critical layers due to the poor Tool Induced Shift (TIS) values. Hence new overlay metrology is required to improve the overlay measurement accuracy. Diffraction Based Overlay (DBO) is regarded to be an alternative metrology to IBO for more accurate measurements and reduction of reading errors. Good overlay performances of DBO have been reported in many articles. However applying DBO for SPT and DPT layers poses extra challenges for target design. New vernier designs are considered for different DPT and SPT schemes to meet overlay target in DBO system. In this paper, we optimize the design of the DBO target and the performance of DBO to meet the overlay specification of sub-3x nm devices which are using SPT and DPT processes. We show that the appropriate vernier design yields excellent overlay performance in residual and TIS. The paper also demonstrated the effects of vernier structure on overlay accuracy from SEM analysis.

  7. Refractory concretes

    International Nuclear Information System (INIS)

    Holcombe, C.E. Jr.

    1979-01-01

    Novel concrete compositions comprise particles of aggregate material embedded in a cement matrix, said cement matrix produced by contacting an oxide selected from the group of Y 2 O 3 , La 2 O 3 , Nd 2 O 3 , Sm 2 O 3 , Eu 2 O 3 and Gd 2 O 3 with an aqueous solution of a salt selected from the group of NH 4 HO 3 , NH 4 Cl, YCl 3 and Mg(NO 3 ) 2 to form a fluid mixture; and allowing the fluid mixture to harden

  8. Concrete construction engineering handbook

    CERN Document Server

    Nawy, Edward G

    2008-01-01

    Provides coverage of concrete construction engineering and technology. This work features discussions focusing on: the advances in engineered concrete materials; reinforced concrete construction; specialized construction techniques; and, design recommendations for high performance.

  9. Experimental analysis of reinforced concrete columns strengthened with Self-Compacting concrete

    Directory of Open Access Journals (Sweden)

    M. Y. M. Omar

    Full Text Available This paper presents the results of reinforced concrete columns strengthened by addition of a self-compacting concrete overlay at the compressed and at the tensioned face of the member, with and without addition of longitudinal steel bars. Eight columns were submit- ted to loading with an initial eccentricity of 60 mm . These columns had 120 mm x 250 mm of rectangular cross section, 2000 mm in length and four longitudinal reinforcement steel bars with 10 mm in diameter. Reference columns P1 and P2 were tested to failure without any type of rehabilitation. Columns P3 to P8 were loaded to a predefined load (close to the initial yield point of tension reinforce- ment, then unloaded and strengthened for a subsequent test until failure. Results showed that the method of rehabilitation used was effective, increasing the loading capacity of the strengthened pieces by 2 to 5 times the ultimate load of the reference column.

  10. Recycled concrete aggregate in portland cement concrete.

    Science.gov (United States)

    2013-01-01

    Aggregates can be produced by crushing hydraulic cement concrete and are known as recycled concrete : aggregates (RCA). This report provides results from a New Jersey Department of Transportation study to identify : barriers to the use of RCA in new ...

  11. Design and performance evaluation of very thin overlays in Texas.

    Science.gov (United States)

    2009-06-01

    Very thin overlays 1-inch thick or less were placed as surface layers on five major highways in Texas. : These mixes were designed in the laboratory to have a balance of good rut resistance as measured by : TxDOTs Hamburg Wheel Tracking test and g...

  12. Residual stress measurement in 304 stainless steel weld overlay pipes

    International Nuclear Information System (INIS)

    Yen, H.J.; Lin, M.C.C.; Chen, L.J.

    1996-01-01

    Welding overlay repair (WOR) is commonly employed to rebuild piping systems suffering from intergranular stress corrosion cracking (IGSCC). To understand the effects of this repair, it is necessary to investigate the distribution of residual stresses in the welding pipe. The overlay welding technique must induce compressive residual stress at the inner surface of the welded pipe to prevent IGSCC. To understand the bulk residual stress distribution, the stress profile as a function of location within wall is examined. In this study the full destructive residual stress measurement technique -- a cutting and sectioning method -- is used to determine the residual stress distribution. The sample is type 304 stainless steel weld overlay pipe with an outside diameter of 267 mm. A pipe segment is cut from the circular pipe; then a thin layer is removed axially from the inner to the outer surfaces until further sectioning is impractical. The total residual stress is calculated by adding the stress relieved by cutting the section away to the stress relieved by axially sectioning. The axial and hoop residual stresses are compressive at the inner surface of the weld overlay pipe. Compressive stress exists not only at the surface but is also distributed over most of the pipe's cross section. On the one hand, the maximum compressive hoop residual stress appears at the pipe's inner surface. The thermal-mechanical induced crack closure from significant compressive residual stress is discussed. This crack closure can thus prevent IGSCC very effectively

  13. Visualization of disciplinary profiles: Enhanced science overlay maps

    NARCIS (Netherlands)

    Carley, S.; Porter, A.L.; Rafols, I.; Leydesdorff, L.

    Purpose The purpose of this study is to modernize previous work on science overlay maps by updating the underlying citation matrix, generating new clusters of scientific disciplines, enhancing visualizations, and providing more accessible means for analysts to generate their own maps.

  14. Plastic collapse moment for pipe repaired with weld overlay

    International Nuclear Information System (INIS)

    Li, Yinsheng; Hasegawa, Kunio; Shibuya, Akira; Deardorff, Arthur

    2009-01-01

    The Weld Overlay has been used in several countries as an effective method to repair the stress corrosion cracks in nuclear power plant piping. However, the method to evaluate the plastic collapse stress for the pipe repaired with Weld Overlay has not been proposed and the limit load criterion for single uniform material has been used to design its structure by now. In this paper, the equations to evaluate the plastic collapse moment for the pipe repaired with Weld Overlay have been derived considering two layer materials. Moreover, several numerical examples are given to show the validity of Weld Overlay. The equations given in this paper are simple to use like the limit load criterion showed in present standards such as JSME Rules on Fitness-for-Service for Nuclear Power Plants or ASME Boiler and Pressure Vessel Code Section XI, and they can not only be used to evaluate the fracture of the pipe, but also be applied to design the weld structure. (author)

  15. The Future Concrete: Self-Compacting Concrete

    Directory of Open Access Journals (Sweden)

    Liana Iureş

    2010-01-01

    Full Text Available The paper presents the characteristics of the self-compacting concretes, their advantages and disadvantages when they are used in buildings. Due to its properties and composition, the self-compacting concrete is described here as being one of the future friendly enviromental material for buildings. Tests concerning to obtaining a self-compacting concrete, together with the specific fresh concrete properties tests, are described.

  16. The Future Concrete: Self-Compacting Concrete

    OpenAIRE

    Iureş, Liana; Bob, Corneliu

    2010-01-01

    The paper presents the characteristics of the self-compacting concretes, their advantages and disadvantages when they are used in buildings. Due to its properties and composition, the self-compacting concrete is described here as being one of the future friendly enviromental material for buildings. Tests concerning to obtaining a self-compacting concrete, together with the specific fresh concrete properties tests, are described.

  17. 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

  18. Modern methods of overlay welding for corrosion protection of power generating equipment

    International Nuclear Information System (INIS)

    Ershov, A.V.; Shul'man, I.E.; Potapov, N.N.

    1989-01-01

    Methods for overlay welding of inner surfaces of power equipment for corrosion protection are analysed. Various methods of electroslag overlay welding by a band electrode (overlay welding by two-electrode bands by a wide band with magnetic control, by an electrode band with high melting velocity) are marked to be the most perspective for cladding of NPP vessel equipment

  19. Visualization of Disciplinary Profiles: Enhanced Science Overlay Maps

    Directory of Open Access Journals (Sweden)

    Stephen Carley

    2017-08-01

    Full Text Available Purpose: The purpose of this study is to modernize previous work on science overlay maps by updating the underlying citation matrix, generating new clusters of scientific disciplines, enhancing visualizations, and providing more accessible means for analysts to generate their own maps. Design/methodology/approach: We use the combined set of 2015 Journal Citation Reports for the Science Citation Index (n of journals = 8,778 and the Social Sciences Citation Index (n = 3,212 for a total of 11,365 journals. The set of Web of Science Categories in the Science Citation Index and the Social Sciences Citation Index increased from 224 in 2010 to 227 in 2015. Using dedicated software, a matrix of 227 × 227 cells is generated on the basis of whole-number citation counting. We normalize this matrix using the cosine function. We first develop the citing-side, cosine-normalized map using 2015 data and VOSviewer visualization with default parameter values. A routine for making overlays on the basis of the map (“wc15.exe” is available at http://www.leydesdorff.net/wc15/index.htm. Findings: Findings appear in the form of visuals throughout the manuscript. In Figures 1–9 we provide basemaps of science and science overlay maps for a number of companies, universities, and technologies. Research limitations: As Web of Science Categories change and/or are updated so is the need to update the routine we provide. Also, to apply the routine we provide users need access to the Web of Science. Practical implications: Visualization of science overlay maps is now more accurate and true to the 2015 Journal Citation Reports than was the case with the previous version of the routine advanced in our paper. Originality/value: The routine we advance allows users to visualize science overlay maps in VOSviewer using data from more recent Journal Citation Reports.

  20. Concrete Memories

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    2015-01-01

    This article traces the presence of Atlantikwall bunkers in amateur holiday snapshots and discusses the ambiguous role of the bunker site in visual cultural memory. Departing from my family’s private photo collection from twenty years of vacationing at the Danish West coast, the different mundane...... and poetic appropriations and inscriptions of the bunker site are depicted. Ranging between overlooked side presences and an overwhelming visibility, the concrete remains of fascist war architecture are involved in and motivate different sensuous experiences and mnemonic appropriations. The article meets...... the bunkers’ changing visuality and the cultural topography they both actively transform and are being transformed by through juxtaposing different acts and objects of memory over time and in different visual articulations....

  1. Self-Compacting Concrete

    OpenAIRE

    Okamura, Hajime; Ouchi, Masahiro

    2003-01-01

    Self-compacting concrete was first developed in 1988 to achieve durable concrete structures. Since then, various investigations have been carried out and this type of concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out from the viewpoint of making self-compacting concrete a standard concrete.

  2. Image-based overlay measurement using subsurface ultrasonic resonance force microscopy

    Science.gov (United States)

    Tamer, M. S.; van der Lans, M. J.; Sadeghian, H.

    2018-03-01

    Image Based Overlay (IBO) measurement is one of the most common techniques used in Integrated Circuit (IC) manufacturing to extract the overlay error values. The overlay error is measured using dedicated overlay targets which are optimized to increase the accuracy and the resolution, but these features are much larger than the IC feature size. IBO measurements are realized on the dedicated targets instead of product features, because the current overlay metrology solutions, mainly based on optics, cannot provide sufficient resolution on product features. However, considering the fact that the overlay error tolerance is approaching 2 nm, the overlay error measurement on product features becomes a need for the industry. For sub-nanometer resolution metrology, Scanning Probe Microscopy (SPM) is widely used, though at the cost of very low throughput. The semiconductor industry is interested in non-destructive imaging of buried structures under one or more layers for the application of overlay and wafer alignment, specifically through optically opaque media. Recently an SPM technique has been developed for imaging subsurface features which can be potentially considered as a solution for overlay metrology. In this paper we present the use of Subsurface Ultrasonic Resonance Force Microscopy (SSURFM) used for IBO measurement. We used SSURFM for imaging the most commonly used overlay targets on a silicon substrate and photoresist. As a proof of concept we have imaged surface and subsurface structures simultaneously. The surface and subsurface features of the overlay targets are fabricated with programmed overlay errors of +/-40 nm, +/-20 nm, and 0 nm. The top layer thickness changes between 30 nm and 80 nm. Using SSURFM the surface and subsurface features were successfully imaged and the overlay errors were extracted, via a rudimentary image processing algorithm. The measurement results are in agreement with the nominal values of the programmed overlay errors.

  3. Perceived effects of coloured overlays on reading material in persons with albinism

    Directory of Open Access Journals (Sweden)

    N. T. Makgaba

    2008-12-01

    Full Text Available Persons with albinism often complain of glare when reading. They may therefore benefit from coloured filter overlays just as they benefit from tinted lenses. The purpose of this study was to assess the effectof coloured overlays on print perception in persons with oculocutaneous albinism (OCA.   Fifty subjects were included in this study, their ages ranged from 12 to 31 years with a mean of 16.12 years (SD = ± 4.56 years.  Following refraction and subsequent compensation for refractive errors, subjective perception of print was examined with the subject looking at the Wilkins® reading rate test chart with and without colored filter overlay/s.  The subjects were asked to respond to questions previously used in a questionnaire by Wilkins (2001. The percentage frequencies of positive (beneficial responses were used to decide whether or not a particular overlay would enhance reading performance.  McNemar’s test was used to establish significant differences between responses to questions without and with overlays. All single overlays gave greater percentages of positive responses (92.0-97.2% than without overlay (85.2%.  The single overlay that provided the highest positive responses was blue (97.2% and the least was purple (92.0%. All double overlays, except grey/grey (82.0% gave greater positive responses than without overlay (85.2%. Aqua/blue gave the greatest positive responses (possible benefits (97.2%, followed by rose/rose (96.8%.  Comparing the responses without overlay with single and double overlays, the difference in responses to the five questions was only significant (p < 0.05 with regard to brightness of the surface. The results suggest that overlays provided a more glare-free reading surface than without an overlay. It was, therefore concluded that the best advantage of the coloured overlays was in glare reduction.  Although this study showed that there were more subjects who preferred single blue and aqua/blue double

  4. On-demand Overlay Networks for Large Scientific Data Transfers

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, Lavanya [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Guok, Chin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jackson, Keith [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kissel, Ezra [Univ. of Delaware, Newark, DE (United States); Swany, D. Martin [Univ. of Delaware, Newark, DE (United States); Agarwal, Deborah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2009-10-12

    Large scale scientific data transfers are central to scientific processes. Data from large experimental facilities have to be moved to local institutions for analysis or often data needs to be moved between local clusters and large supercomputing centers. In this paper, we propose and evaluate a network overlay architecture to enable highthroughput, on-demand, coordinated data transfers over wide-area networks. Our work leverages Phoebus and On-demand Secure Circuits and AdvanceReservation System (OSCARS) to provide high performance wide-area network connections. OSCARS enables dynamic provisioning of network paths with guaranteed bandwidth and Phoebus enables the coordination and effective utilization of the OSCARS network paths. Our evaluation shows that this approach leads to improved end-to-end data transfer throughput with minimal overheads. The achievedthroughput using our overlay was limited only by the ability of the end hosts to sink the data.

  5. An Overlay Architecture for Throughput Optimal Multipath Routing

    Science.gov (United States)

    2017-01-14

    maximum throughput. Finally, we propose a threshold-based policy (BP-T) and a heuristic policy (OBP), which dynamically control traffic bifurcations...network stability region is available . Second, given any subset of nodes that are controllable, we also wish to develop an optimal routing policy that...case when tunnels do not overlap. We also develop a heuristic overlay control policy for use on general topologies, and show through simulation that

  6. Complexity Leadership Theory: A United States Marine Corps Historical Overlay

    Science.gov (United States)

    2017-05-25

    DD-MM-YYYY) 23-04-2017 2. REPORT TYPE Master’s Thesis 3. DATES COVERED (From - To) JUN 2016 – MAY 2017 4. TITLE AND SUBTITLE Complexity...Monograph Title : Complexity Leadership Theory : A United States Marine Corps Historical Overlay Approved by...General Ridgway’s Success in Korea.” Master’s thesis , United States Army Command and General Staff College, 2010. Diana, Gabriel. “Vision, Education

  7. Advancements of diffraction-based overlay metrology for double patterning

    Science.gov (United States)

    Li, Jie; Kritsun, Oleg; Liu, Yongdong; Dasari, Prasad; Weher, Ulrich; Volkman, Catherine; Mazur, Martin; Hu, Jiangtao

    2011-03-01

    As the dimensions of integrated circuit continue to shrink, diffraction based overlay (DBO) technologies have been developed to address the tighter overlay control challenges. Previously data of high accuracy and high precision were reported for litho-etch-litho-etch double patterning (DP) process using normal incidence spectroscopic reflectometry on specially designed targets composed of 1D gratings in x and y directions. Two measurement methods, empirical algorithm (eDBO) using four pads per direction (2x4 target) and modeling based algorithm (mDBO) using two pads per direction (2x2 target) were performed. In this work, we apply DBO techniques to measure overlay errors for a different DP process, litho-freeze-litho-etch process. We explore the possibility of further reducing number of pads in a DBO target using mDBO. For standard targets composed of 1D gratings, we reported results for eDBO 2x4 targets, mDBO 2x2 targets, and mDBO 2x1 target. The results of all three types of targets are comparable in terms of accuracy, dynamic precision, and TIS. TMU (not including tool matching) is less than 0.1nm. In addition, we investigated the possibility of measuring overlay with one single pad that contains 2D gratings. We achieved good correlation to blossom measurements. TMU (not including tool matching) is ~ 0.2nm. To our best knowledge, this is the first time that DBO results are reported on a single pad. eDBO allows quick recipe setup but takes more space and measurement time. Although mDBO needs details of optical properties and modeling, it offers smaller total target size and much faster throughput, which is important in high volume manufacturing environment.

  8. Development of new engine bearings with overlay consisting of solid lubricants; Kotai junkatsu overlay tsuki engine yo suberi jikuuke zairyo no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kanayama, H; Kawakami, S; Gohara, C [Taiho Kogyo Co. Ltd., Aichi (Japan); Fuwa, Y; Michioka, H [Toyota Motor Corp., Aichi (Japan)

    1997-10-01

    Recently, modern engines have a tendency for higher output and longer periods. As a result , higher bearing performance is required. For this reason, we have developed the new conceptual overlay consisting of solid lubricants and thermosetting plastics. This paper describes the performance of engine bearings with the new overlay. 5 refs., 13 figs., 5 tabs.

  9. Residual stress reduction in the penetration nozzle weld joint by overlay welding

    International Nuclear Information System (INIS)

    Jiang, Wenchun; Luo, Yun; Wang, B.Y.; Tu, S.T.; Gong, J.M.

    2014-01-01

    Highlights: • Residual stress reduction in penetration weld nozzle by overlay welding was studied. • The overlay weld can decrease the residual stress in the weld root. • Long overlay welding is proposed in the actual welding. • Overlay weld to decrease residual stress is more suitable for thin nozzle. - Abstract: Stress corrosion cracking (SCC) in the penetration nozzle weld joint endangers the structural reliability of pressure vessels in nuclear and chemical industries. How to decrease the residual stress is very critical to ensure the structure integrity. In this paper, a new method, which uses overlay welding on the inner surface of nozzle, is proposed to decrease the residual stresses in the penetration joint. Finite element simulation is used to study the change of weld residual stresses before and after overlay welding. It reveals that this method can mainly decrease the residual stress in the weld root. Before overlay welding, large tensile residual stresses are generated in the weld root. After overlay weld, the tensile hoop stress in weld root has been decreased about 45%, and the radial stress has been decreased to compressive stress, which is helpful to decrease the susceptibility to SCC. With the increase of overlay welding length, the residual stress in weld root has been greatly decreased, and thus the long overlay welding is proposed in the actual welding. It also finds that this method is more suitable for thin nozzle rather than thick nozzle

  10. Fibre Concrete 2017

    Science.gov (United States)

    2017-09-01

    9th international conference on fibre reinforced concretes (FRC), textile reinforced concretes (TRC) and ultra-high performance concretes (UHPC) Preface The Fibre Concrete Conference series is held biennially to provide a platform to share knowledge on fibre reinforced concretes, textile concretes and ultra-high performance concretes regarding material properties and behaviour, technology procedures, topics of long-term behaviour, creep, durability; sustainable aspects of concrete including utilisation of waste materials in concrete production and recycling of concrete. The tradition of Fibre Concrete Conferences started in eighties of the last century. Nowadays the conference is organized by the Department of Concrete and Masonry Structures of the Czech Technical University in Prague, Faculty of Civil Engineering. The 9th International Conference Fibre Concrete 2017 had 109 participants from 27 countries all over the world. 55 papers were presented including keynote lectures of Professor Bažant, Professor Bartoš and Dr. Broukalová. The conference program covered wide range of topics from scientific research to practical applications. The presented contributions related to performance and behaviour of cement based composites, their long-term behaviour and durability, sustainable aspects, advanced analyses of structures from these composites and successful applications. This conference was organized also to honour Professor Zděnek P. Bažant on the occasion of his jubilee and to appreciate his merits and discoveries in the field of fibre reinforced composites, structural mechanics and engineering.

  11. Sustainable Concrete Technology

    Directory of Open Access Journals (Sweden)

    Sim J.

    2015-12-01

    Full Text Available The growing concern over global warming and significant ecological changes requires sustainable development in all fields of science and technology. Concrete not only consumes huge amount of energy and natural sources, but also emits large amount of CO2, mainly due to the production of cement. It is evident that such large amount of concrete production has put significant impact on the energy, resource, environment, and ecology of the society. Hence, how to develop the concrete technology in a sustainable way has become a significant issue. In this paper, some of Korean researches for sustainable development of concrete are presented. These are sustainable strengthening for deteriorated concrete structure, sustainable reinforcement of new concrete structure, sustainable concrete using recycled aggregate and supplementary cementing materials and finally application of each technique to precast concrete.

  12. Concrete pavement joint deterioration.

    Science.gov (United States)

    2015-12-01

    Concrete pavements are an important part of our national infrastructure. In recent years the relatively small number of reported joints deteriorating prematurely in concrete pavements around Indiana has increased. Changes over the past 45 years in IN...

  13. 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...

  14. Lunar concrete for construction

    Science.gov (United States)

    Cullingford, Hatice S.; Keller, M. Dean

    1988-01-01

    Feasibility of using concrete for lunar-base construction has been discussed recently without relevant data for the effects of vacuum on concrete. Experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the moon are provided in this paper along with specific conclusions from the existing data base.

  15. Reinforced sulphur concrete

    NARCIS (Netherlands)

    2014-01-01

    Reinforced sulphur concrete wherein one or more metal reinforcing members are in contact with sulphur concrete is disclosed. The reinforced sulphur concrete comprises an adhesion promoter that enhances the interaction between the sulphur and the one or more metal reinforcing members.

  16. Deterioration of Concrete Structures

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Chloride ingress is a common cause of deterioration of reinforced concrete bridges. Concrete may be exposed to chloride by seawater or de-icing salts. The chloride initiates corrosion of the reinforcement, which through expansion disrupts the concrete. In addition, the corrosion reduces the cross...

  17. concrete5 for developers

    CERN Document Server

    Uzayr, Sufyan bin

    2014-01-01

    Whether you have had some previous experience with concrete5 or are entirely new to it, this book will help you understand all that you need to know in order to get started with concrete5 development. A background in PHP is required; some knowledge of HTML/CSS is needed in order to fully grasp the concepts underlying concrete5 theme development.

  18. Cluster-assembled overlayers and high-temperature superconductors

    International Nuclear Information System (INIS)

    Ohno, T.R.; Yang, Y.; Kroll, G.H.; Krause, K.; Schmidt, L.D.; Weaver, J.H.; Kimachi, Y.; Hidaka, Y.; Pan, S.H.; de Lozanne, A.L.

    1991-01-01

    X-ray photoemission results for interfaces prepared by cluster assembly with nanometer-size clusters deposited on high-T c superconductors (HTS's) show a reduction in reactivity because atom interactions with the surface are replaced by cluster interactions. Results for conventional atom deposition show the formation of overlayer oxides that are related to oxygen depletion and disruption of the near-surface region of the HTS's. For cluster assembly of Cr and Cu, there is a very thin reacted region on single-crystal Bi 2 Sr 2 CaCu 2 O 8 . Reduced reactivity is observed for Cr cluster deposition on single-crystal YBa 2 Cu 3 O 7 -based interfaces. There is no evidence of chemical modification of the surface for Ge and Au cluster assembly on Bi 2 Sr 2 CaCu 2 O 8 (100). The overlayer grown by Au cluster assembly on Bi 2 Sr 2 CaCu 2 O 8 covers the surface at low temperature but roughening occurs upon warming to 300 K. Scanning-tunneling-microscopy results for the Au(cluster)/Bi 2 Sr 2 CaCu 2 O 8 system warmed to 300 K shows individual clusters that have coalesced into large clusters. These results offer insight into the role of surface energies and cluster interactions in determining the overlayer morphology. Transmission-electron-microscopy results for Cu cluster assembly on silica show isolated irregularly shaped clusters that do not interact at low coverage. Sintering and labyrinth formation is observed at intermediate coverage and, ultimately, a continuous film is achieved at high coverage. Silica surface wetting by Cu clusters demonstrates that dispersive force are important for these small clusters

  19. THE FUZZY OVERLAY STUDENT MODEL IN AN INTELLIGENT TUTORING SYSTEM

    Directory of Open Access Journals (Sweden)

    D. I. Popov

    2015-01-01

    Full Text Available The article is devoted to the development of the student model for use in an intelligent tutoring system (ITS designed for the evaluation of students’ competencies in different Higher Education Facilities. There are classification and examples of the various student models, the most suitable for the evaluation of competencies is selected and finalized. The dynamic overlay fuzzy student model builded on the domain model based on the concept of didactic units is described in this work. The formulas, chart and diagrams are provided.

  20. Bandwidth auction for SVC streaming in dynamic multi-overlay

    Science.gov (United States)

    Xiong, Yanting; Zou, Junni; Xiong, Hongkai

    2010-07-01

    In this paper, we study the optimal bandwidth allocation for scalable video coding (SVC) streaming in multiple overlays. We model the whole bandwidth request and distribution process as a set of decentralized auction games between the competing peers. For the upstream peer, a bandwidth allocation mechanism is introduced to maximize the aggregate revenue. For the downstream peer, a dynamic bidding strategy is proposed. It achieves maximum utility and efficient resource usage by collaborating with a content-aware layer dropping/adding strategy. Also, the convergence of the proposed auction games is theoretically proved. Experimental results show that the auction strategies can adapt to dynamic join of competing peers and video layers.

  1. Ductile film delamination from compliant substrates using hard overlayers.

    Science.gov (United States)

    Cordill, M J; Marx, V M; Kirchlechner, C

    2014-11-28

    Flexible electronic devices call for copper and gold metal films to adhere well to polymer substrates. Measuring the interfacial adhesion of these material systems is often challenging, requiring the formulation of different techniques and models. Presented here is a strategy to induce well defined areas of delamination to measure the adhesion of copper films on polyimide substrates. The technique utilizes a stressed overlayer and tensile straining to cause buckle formation. The described method allows one to examine the effects of thin adhesion layers used to improve the adhesion of flexible systems.

  2. Decoupling of Solid 4He Layers under the Superfluid Overlayer

    Science.gov (United States)

    Ishibashi, Kenji; Hiraide, Jo; Taniguchi, Junko; Suzuki, Masaru

    2018-03-01

    It has been reported that in a large oscillation amplitude, the mass decoupling of multilayer 4He films adsorbed on graphite results from the depinning of the second solid atomic layer. This decoupling suddenly vanishes below a certain low temperature TD due to the cancellation of mass decoupling by the superfluid counterflow of the the overylayer. We studied the relaxation of the depinned state at various temperatures, after reduction of oscillation amplitude below TD . It was found that above the superfluid transition temperature the mass decoupling revives with a relaxation time of several 100 s. It strongly supports that the depinned state of the second solid atomic layer remains underneath the superfluid overlayer.

  3. Opportunistic transmitter selection for selfless overlay cognitive radios

    KAUST Repository

    Shaqfeh, Mohammad

    2013-11-01

    We propose an opportunistic strategy to grant channel access to the primary and secondary transmitters in causal selfless overlay cognitive radios over block-fading channels. The secondary transmitter helps the primary transmitter by relaying the primary messages opportunistically, aided by a buffer to store the primary messages temporarily. The optimal channel-aware transmitter- selection strategy is the solution of the maximization of the average secondary rate under the average primary rate requirement and the buffer stability constraints. Numerical results demonstrate the gains of the proposed opportunistic selection strategy. © 2013 IEEE.

  4. Leveraging Gaussian process approximations for rapid image overlay production

    CSIR Research Space (South Africa)

    Burke, Michael

    2017-10-01

    Full Text Available value, xs = argmax x∗ [ K (x∗, x∗) − K (x∗, x)K (x, x)−1K (x, x∗) ] . (10) Figure 2 illustrates this sampling strategy more clearly. This selec- tion process can be slow, but could be bootstrapped using Latin hypercube sampling [16]. 3 RESULTS Empirical... point - a 240 sample Gaussian process approximation takes roughly the same amount of time to compute as the full blanked overlay. GP 50 GP 100 GP 150 GP 200 GP 250 GP 300 GP 350 GP 400 Full Itti-Koch 0 2 4 6 8 10 Method R at in g Boxplot of storyboard...

  5. Examination of overlay pipe weldments removed from the Hatch-2 reactor

    International Nuclear Information System (INIS)

    Park, J.Y.; Kupperman, D.S.; Shack, W.J.

    1985-02-01

    Laboratory ultrasonic examination (UT), dye penetrant examination (PT), metallography, and sensitization measurements were performed on Type 304 stainless steel overlay pipe weldments from the Hatch-2 BWR to determine the effectiveness of UT through overlays and the effects of the overlays on crack propagation in the weldments. Little correlation was observed between the results of earlier in-service ultrasonic inspection and the results of PT and destructive examination. Considerable difficulty was encountered in correctly detecting the presence of cracks by UT in the laboratory. Blunting of the crack tip by the weld overlay was observed, but there was no evidence of tearing or throughwall extension of the crack beyond the blunted region

  6. Modified pavement cement concrete

    Science.gov (United States)

    Botsman, L. N.; Ageeva, M. S.; Botsman, A. N.; Shapovalov, S. M.

    2018-03-01

    The paper suggests design principles of pavement cement concrete, which covers optimization of compositions and structures at the stage of mixture components selection due to the use of plasticizing agents and air-retaining substances that increase the viability of a concrete mixture. It also demonstrates advisability of using plasticizing agents together with air-retaining substances when developing pavement concrete compositions, which provides for the improvement of physical and mechanical properties of concrete and the reduction of cement binding agent consumption thus preserving strength indicators. The paper shows dependences of the main physical-mechanical parameters of concrete on cement consumption, a type and amount of additives.

  7. Material properties characterization - concrete

    International Nuclear Information System (INIS)

    England, G.L.; MacLeod, J.S.

    1978-01-01

    A review is presented of the six contributions in the SMiRT 4 conference to Session H5 on structural analysis of prestressed concrete reactor pressure vessels. These relate to short term stress-strain aspects of concrete loaded beyond the linear range in uniaxial and biaxial stress fields, to some time and temperature dependent properties of concrete at working stress levels, and to a programme of strain-gauge testing for the assessment of concrete properties. From the information discussed, it is clear that there are difficulties in determining material properties for concrete, and these are summarised. (UK)

  8. Autogenous Deformation of Concrete

    DEFF Research Database (Denmark)

    Autogenous deformation of concrete can be defined as the free deformation of sealed concrete at a constant temperature. A number of observed problems with early age cracking of high-performance concretes can be attributed to this phenomenon. During the last 10 years , this has led to an increased...... focus on autogenous deformation both within concrete practice and concrete research. Since 1996 the interest has been significant enough to hold international, yearly conferences entirely devoted to this subject. The papers in this publication were presented at two consecutive half-day sessions...... at the American Concrete Institute’s Fall Convention in Phoenix, Arizona, October 29, 2002. All papers have been reviewed according to ACI rules. This publication, as well as the sessions, was sponsored by ACI committee 236, Material Science of Concrete. The 12 presentations from 8 different countries indicate...

  9. Recycled Concrete as Aggregate for Structural Concrete Production

    OpenAIRE

    Mirjana Malešev; Vlastimir Radonjanin; Snežana Marinković

    2010-01-01

    A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC) as a control concrete and two types of concrete made with natural fine and recycle...

  10. Lightweight storage and overlay networks for fault tolerance.

    Energy Technology Data Exchange (ETDEWEB)

    Oldfield, Ron A.

    2010-01-01

    The next generation of capability-class, massively parallel processing (MPP) systems is expected to have hundreds of thousands to millions of processors, In such environments, it is critical to have fault-tolerance mechanisms, including checkpoint/restart, that scale with the size of applications and the percentage of the system on which the applications execute. For application-driven, periodic checkpoint operations, the state-of-the-art does not provide a scalable solution. For example, on today's massive-scale systems that execute applications which consume most of the memory of the employed compute nodes, checkpoint operations generate I/O that consumes nearly 80% of the total I/O usage. Motivated by this observation, this project aims to improve I/O performance for application-directed checkpoints through the use of lightweight storage architectures and overlay networks. Lightweight storage provide direct access to underlying storage devices. Overlay networks provide caching and processing capabilities in the compute-node fabric. The combination has potential to signifcantly reduce I/O overhead for large-scale applications. This report describes our combined efforts to model and understand overheads for application-directed checkpoints, as well as implementation and performance analysis of a checkpoint service that uses available compute nodes as a network cache for checkpoint operations.

  11. Simple overlay device for determining radial head and neck height

    International Nuclear Information System (INIS)

    Moon, Jun-Gyu; Southgate, Richard D.; Fitzsimmons, James S.; O'Driscoll, Shawn W.

    2010-01-01

    The purpose of this study was to test the hypothesis that a simple overlay device can be used on radiographs to measure radial head and neck height. Thirty anteroposterior elbow radiographs from 30 patients with a clinical diagnosis of lateral epicondylitis were examined to measure radial head and neck height. Three methods using different points along the bicipital tuberosity as a landmark were used. Method 1 used the proximal end of the bicipital tuberosity, method 2 used the most prominent point of the bicipital tuberosity, and method 3 used a simple overlay device (SOD) template that was aligned with anatomic reference points. All measurements were performed three times by three observers to determine interobserver and intraobserver reliability. Intraclass correlation coefficients revealed higher interobserver and intraobserver correlations for the SOD template method than for the other two methods. The 95% limits of agreement between observers were markedly better (-1.8 mm to +1.0 mm) for the SOD template method than for the proximal point method (-3.8 mm to +3.4 mm) or the prominent point method (-5.9 mm to +4.9 mm). We found that the SOD template method was reliable for assessing radial head and neck height. It had less variability than other methods, its 95% limit of agreement being less than 2 mm. This method could be helpful for assessing whether or not the insertion of a radial head prosthesis has resulted in over-lengthening of the radius. (orig.)

  12. Simple overlay device for determining radial head and neck height

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Jun-Gyu; Southgate, Richard D.; Fitzsimmons, James S.; O' Driscoll, Shawn W. [Mayo Clinic, Department of Orthopaedic Surgery, Rochester, MN (United States)

    2010-09-15

    The purpose of this study was to test the hypothesis that a simple overlay device can be used on radiographs to measure radial head and neck height. Thirty anteroposterior elbow radiographs from 30 patients with a clinical diagnosis of lateral epicondylitis were examined to measure radial head and neck height. Three methods using different points along the bicipital tuberosity as a landmark were used. Method 1 used the proximal end of the bicipital tuberosity, method 2 used the most prominent point of the bicipital tuberosity, and method 3 used a simple overlay device (SOD) template that was aligned with anatomic reference points. All measurements were performed three times by three observers to determine interobserver and intraobserver reliability. Intraclass correlation coefficients revealed higher interobserver and intraobserver correlations for the SOD template method than for the other two methods. The 95% limits of agreement between observers were markedly better (-1.8 mm to +1.0 mm) for the SOD template method than for the proximal point method (-3.8 mm to +3.4 mm) or the prominent point method (-5.9 mm to +4.9 mm). We found that the SOD template method was reliable for assessing radial head and neck height. It had less variability than other methods, its 95% limit of agreement being less than 2 mm. This method could be helpful for assessing whether or not the insertion of a radial head prosthesis has resulted in over-lengthening of the radius. (orig.)

  13. Virtual overlay metrology for fault detection supported with integrated metrology and machine learning

    Science.gov (United States)

    Lee, Hong-Goo; Schmitt-Weaver, Emil; Kim, Min-Suk; Han, Sang-Jun; Kim, Myoung-Soo; Kwon, Won-Taik; Park, Sung-Ki; Ryan, Kevin; Theeuwes, Thomas; Sun, Kyu-Tae; Lim, Young-Wan; Slotboom, Daan; Kubis, Michael; Staecker, Jens

    2015-03-01

    While semiconductor manufacturing moves toward the 7nm node for logic and 15nm node for memory, an increased emphasis has been placed on reducing the influence known contributors have toward the on product overlay budget. With a machine learning technique known as function approximation, we use a neural network to gain insight to how known contributors, such as those collected with scanner metrology, influence the on product overlay budget. The result is a sufficiently trained function that can approximate overlay for all wafers exposed with the lithography system. As a real world application, inline metrology can be used to measure overlay for a few wafers while using the trained function to approximate overlay vector maps for the entire lot of wafers. With the approximated overlay vector maps for all wafers coming off the track, a process engineer can redirect wafers or lots with overlay signatures outside the standard population to offline metrology for excursion validation. With this added flexibility, engineers will be given more opportunities to catch wafers that need to be reworked, resulting in improved yield. The quality of the derived corrections from measured overlay metrology feedback can be improved using the approximated overlay to trigger, which wafers should or shouldn't be, measured inline. As a development or integration engineer the approximated overlay can be used to gain insight into lots and wafers used for design of experiments (DOE) troubleshooting. In this paper we will present the results of a case study that follows the machine learning function approximation approach to data analysis, with production overlay measured on an inline metrology system at SK hynix.

  14. Concrete laying laboratory

    International Nuclear Information System (INIS)

    Bastlova, K.

    1986-01-01

    The task of the concrete laying laboratory established within a special department for quality control and assurance at the Dukovany nuclear power plant, is to check the composition of concrete mixes produced by the central concrete production plant on the site, and the shipment, laying and processing of concrete. The composition is given of special barite and serpentinite concretes designed for biological shields. The system of checks and of filing the results is briefly described. Esperience is summed up from the operation of the concrete laying laboratory, and conclusions are formulated which should be observed on similar large construction sites. They include the precise definition of the designer's requirements for the quality of concrete, the surface finish of concrete surfaces, the method of concreting specific structures around bushings, increased density reinforcements and various technological elements, and requirements for shipment to poorly accessible or remote places. As for the equipment of the laboratory, it should be completed with an instrument for the analysis of fresh concrete mixes, a large capacity drying kiln, etc. (Z.M.)

  15. Special protective concretes

    International Nuclear Information System (INIS)

    Bouniol, P.

    2001-01-01

    Concrete is the most convenient material when large-scale radiation protection is needed. Thus, special concretes for nuclear purposes are used in various facilities like reactors, reprocessing centers, storage sites, accelerators, hospitals with nuclear medicine equipment, food ionization centers etc.. The recent advances made in civil engineering for the improvement of concrete durability and compactness are for a large part transposable to protection concretes. This article presents the basic knowledge about protection concretes with the associated typological and technological aspects. A large part is devoted to the intrinsic properties of concretes and to their behaviour in irradiation and temperature conditions: 1 - definition and field of application of special protective concretes; 2 - evolution of concepts and technologies (durability of structures, techniques of formulation, new additives, market evolution); 3 - design of protective structures (preliminary study, radiation characteristics, thermal constraints, damping and dimensioning, mechanical criteria); 4 - formulation of special concretes (general principles, granulates, hydraulic binders, pulverulent additives, water/cement ratio, reference composition of some special concretes); 5 - properties of special concretes (damping and thermo-mechanical properties); 6 - induced-irradiation and temperature phenomena (activation, radiolysis, mineralogical transformations, drying, shrinking, creep, corrosion of reinforcement). (J.S.)

  16. Bandwidth and power allocation for two-way relaying in overlay cognitive radio systems

    KAUST Repository

    Alsharoa, Ahmad M.; Ghazzai, Hakim; Yaacoub, Elias E.; Alouini, Mohamed-Slim

    2014-01-01

    In this paper, the problem of both bandwidth and power allocation for two-way multiple relay systems in overlay cognitive radio (CR) setup is investigated. In the CR overlay mode, primary users (PUs) cooperate with cognitive users (CUs) for mutual

  17. Effectiveness of polymer bridge deck overlays in highway noise reduction : technical paper.

    Science.gov (United States)

    2016-04-01

    The Kansas Department of Transportation (KDOT) began placing multi-layer polymer bridge deck overlays in 1999 and at the present time have over 200 in service. A few years after placing the overlays, individuals indicated that they noticed how quiet ...

  18. Nanostructured silicate polymer concrete

    Directory of Open Access Journals (Sweden)

    Figovskiy Oleg L'vovich

    2014-03-01

    Full Text Available It has been known that acid-resistant concretes on the liquid glass basis have high porosity (up to 18~20 %, low strength and insufficient water resistance. Significant increasing of silicate matrix strength and density was carried out by incorporation of special liquid organic alkali-soluble silicate additives, which block superficial pores and reduce concrete shrinkage deformation. It was demonstrated that introduction of tetrafurfuryloxisilane additive sharply increases strength, durability and shock resistance of silicate polymer concrete in aggressive media. The experiments showed, that the strength and density of silicate polymer concrete increase in case of decreasing liquid glass content. The authors obtained optimal content of silicate polymer concrete, which possesses increased strength, durability, density and crack-resistance. Diffusive permeability of concrete and its chemical resistance has been investigated in various corroding media.

  19. Analysis of an Orthotropic Deck Stiffened with a Cement-Based Overlay

    DEFF Research Database (Denmark)

    Walter, Rasmus; Olesen, John Forbes; Stang, Henrik

    2007-01-01

    decks. A solution might be to enhance the stiffness of the traditional orthotropic bridge deck by using a cement-based overlay. In this paper, an orthotropic steel bridge deck stiffened with a cement-based overlay is analyzed. The analysis is based on nonlinear fracture mechanics, and utilizes......Over the past years, with increasing traffic volumes and higher wheel loads, fatigue damage in steel parts of typical orthotropic steel bridge decks has been experienced on heavily trafficked routes. A demand exists to find a durable system to increase the fatigue safety of orthotropic steel bridge...... the finite-element method. The stiffness of the steel deck reinforced with an overlay depends highly on the composite action. The composite action is closely related to cracking of the overlay and interfacial cracking between the overlay and underlying steel plate (debonding). As an example, a real size...

  20. Fundamentals of overlay measurement and inspection using scanning electron-microscope

    Science.gov (United States)

    Kato, T.; Okagawa, Y.; Inoue, O.; Arai, K.; Yamaguchi, S.

    2013-04-01

    Scanning electron-microscope (SEM) has been successfully applied to CD measurement as promising tools for qualifying and controlling quality of semiconductor devices in in-line manufacturing process since 1985. Furthermore SEM is proposed to be applied to in-die overlay monitor in the local area which is too small to be measured by optical overlay measurement tools any more, when the overlay control limit is going to be stringent and have un-ignorable dependence on device pattern layout, in-die location, and singular locations in wafer edge, etc. In this paper, we proposed new overlay measurement and inspection system to make an effective use of in-line SEM image, in consideration of trade-off between measurement uncertainty and measurement pattern density in each SEM conditions. In parallel, we make it clear that the best hybrid overlay metrology is in considering each tool's technology portfolio.

  1. Evaluation of recycled concrete as aggregate in new concrete pavements.

    Science.gov (United States)

    2014-04-01

    This study evaluated the use of recycled concrete as coarse aggregate in new concrete pavements. : Recycled concrete aggregate (RCA) produced from demolished pavements in three geographically dispersed locations in Washington state were used to perfo...

  2. Concrete portable handbook

    CERN Document Server

    Woodson, R Dodge

    2011-01-01

    Whether or not, you are on the job site or back in the office, this book will help you to avoid mistakes, code violations, and wasted time and money. The book's four part treatment begins with constituent materials followed by self contained parts on Concrete Properties, Processes, and Concrete Repair and Rehabilitation. Designed to be an ""all in one"" reference, the author includes a wealth information for the most popular types of testing. This includes: Analysis of Fresh Concrete; Testing Machines; Accelerated Testing Methods; Analysis of Hardened Concrete and Mortar; Core Sampl

  3. Computer vision and soft computing for automatic skull-face overlay in craniofacial superimposition.

    Science.gov (United States)

    Campomanes-Álvarez, B Rosario; Ibáñez, O; Navarro, F; Alemán, I; Botella, M; Damas, S; Cordón, O

    2014-12-01

    Craniofacial superimposition can provide evidence to support that some human skeletal remains belong or not to a missing person. It involves the process of overlaying a skull with a number of ante mortem images of an individual and the analysis of their morphological correspondence. Within the craniofacial superimposition process, the skull-face overlay stage just focuses on achieving the best possible overlay of the skull and a single ante mortem image of the suspect. Although craniofacial superimposition has been in use for over a century, skull-face overlay is still applied by means of a trial-and-error approach without an automatic method. Practitioners finish the process once they consider that a good enough overlay has been attained. Hence, skull-face overlay is a very challenging, subjective, error prone, and time consuming part of the whole process. Though the numerical assessment of the method quality has not been achieved yet, computer vision and soft computing arise as powerful tools to automate it, dramatically reducing the time taken by the expert and obtaining an unbiased overlay result. In this manuscript, we justify and analyze the use of these techniques to properly model the skull-face overlay problem. We also present the automatic technical procedure we have developed using these computational methods and show the four overlays obtained in two craniofacial superimposition cases. This automatic procedure can be thus considered as a tool to aid forensic anthropologists to develop the skull-face overlay, automating and avoiding subjectivity of the most tedious task within craniofacial superimposition. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Overlay improvement by exposure map based mask registration optimization

    Science.gov (United States)

    Shi, Irene; Guo, Eric; Chen, Ming; Lu, Max; Li, Gordon; Li, Rivan; Tian, Eric

    2015-03-01

    Along with the increased miniaturization of semiconductor electronic devices, the design rules of advanced semiconductor devices shrink dramatically. [1] One of the main challenges of lithography step is the layer-to-layer overlay control. Furthermore, DPT (Double Patterning Technology) has been adapted for the advanced technology node like 28nm and 14nm, corresponding overlay budget becomes even tighter. [2][3] After the in-die mask registration (pattern placement) measurement is introduced, with the model analysis of a KLA SOV (sources of variation) tool, it's observed that registration difference between masks is a significant error source of wafer layer-to-layer overlay at 28nm process. [4][5] Mask registration optimization would highly improve wafer overlay performance accordingly. It was reported that a laser based registration control (RegC) process could be applied after the pattern generation or after pellicle mounting and allowed fine tuning of the mask registration. [6] In this paper we propose a novel method of mask registration correction, which can be applied before mask writing based on mask exposure map, considering the factors of mask chip layout, writing sequence, and pattern density distribution. Our experiment data show if pattern density on the mask keeps at a low level, in-die mask registration residue error in 3sigma could be always under 5nm whatever blank type and related writer POSCOR (position correction) file was applied; it proves random error induced by material or equipment would occupy relatively fixed error budget as an error source of mask registration. On the real production, comparing the mask registration difference through critical production layers, it could be revealed that registration residue error of line space layers with higher pattern density is always much larger than the one of contact hole layers with lower pattern density. Additionally, the mask registration difference between layers with similar pattern density

  5. Overlay cognitive radio systems with adaptive two-way relaying

    KAUST Repository

    Hyadi, Amal

    2013-12-01

    In this paper, we propose a spectrum sharing mechanism with a two-phase two-way relaying protocol for an overlay cognitive network. The system comprises two primary users (PUs) and two secondary users (SUs). One of the SUs acts as a relay for the PUs and gains spectrum sharing as long as he respects outage probability constraints of the primary system. Moreover, we consider that the relaying node performs an optimal power allocation scheme that minimizes the outage performance of the secondary receiver. Closed form expressions for the outage probability are derived for the cases of Decode-and-Forward (DF), Amplify-and-Forward (AF), and adaptive relaying. Numerical simulations are presented to illustrate and compare the obtained results. © 2013 IEEE.

  6. Towards Rational Design Method for Strengthening of Concrete Structures by External Bonding

    Directory of Open Access Journals (Sweden)

    Furuuchi H.

    2012-01-01

    Full Text Available Many infrastructures need to be repaired or strengthened due to various reasons, such as unexpected deterioration and changes in performance requirement. This paper presents the following recent achievements by the authors’ group on design method for flexural strengthening of concrete structures by external bonding; (i fracture characteristics of interface between substrate concrete and cementitious overlay, (ii crack spacing of flexural strengthened beams, which affects debonding strength, (iii strengths of intermediate crack (IC debonding and end peeling, (iv strength of concrete cover separation, and (v effectiveness of strengthening by external bonding. A unified approach for flexural strengthening by steel plate, fiber reinforced polymer lami¬nate and cementitious overlay, for both intermediate crack (IC debonding, including end peeling, and concrete cover separation is pre¬sented with consideration of crack spacing in the streng¬thened members. Appropriate interfacial rough¬¬¬ness to achieve efficient interface bond property is clari¬fied and the concept of effectiveness of strengthen¬ing is proposed for better strengthening design.

  7. LIGHTWEIGHT CONCRETE BASED GRANSHLAK

    Directory of Open Access Journals (Sweden)

    NETESA M. I.

    2016-02-01

    Full Text Available Raising of problem. Concrete advisable to obtain a low strength with local secondary resources for recycling and reduce the environmental burden on the environment. But it is important to design such concrete compositions with a reduced flow of cement. It is known that the coefficient of efficiency of use of cement in the concrete of the heavy and B10 is less than about 0.5, which is almost two times smaller than in class B15 concrete and above. Even lower coefficient of efficiency in light concrete cement low strength. Therefore, it is important to find patterns determining the composition of lightweight concrete based on local-products industry with more efficient use of cement in them. Purpose.. Based on the analysis of earlier research results, including with the use of methods of mathematical planning of experiments to determine the concrete contents, which can provide the requirements for the underlying layers of the floor, the compressive strength of which should correspond to the class B5. It is important to provide the required strength at minimum flow of the cement, which is the most expensive and energy-intensive part of concrete. Conclusion. Analysis of the test results of control samples of concrete in 28-day-old, the following laws. The required tensile strength of concrete compressive strength of 7.0 MPa can be obtained in the test range when used in formulations as a filler as the Dnieper hydroelectric power station fly ash and tailings Krivoy Rog iron ore YuGOK. To ensure providing the required characteristic strength of the concrete in the underlying layers of the floor is advisable to use a nominal composition per cubic meter of concrete: cement 160 kg granshlaka Plant named after Petrovsky, 675 kg of fly ash Dnieper HPP 390 kg, 400 kg of sand, 230 liters of water. Thus, while ensuring rational grain composition components can obtain the desired strength lightweight concrete based granshlaka plant Petrovsky, using as fillers

  8. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    The durability of MOC concrete compositions against extreme environmental conditions viz. heating–cooling, freezing–thawing, wetting–drying and penetration and deposition of salts etc were investigated. The results reveal that MOC concrete has high compressive strength associated with high flexural strength and the ...

  9. Radiographic testing of concrete

    International Nuclear Information System (INIS)

    Porter, James F.

    1997-01-01

    The increase in construction activity in the Philippines, reinforced concrete building is still a favorite among designers, because it is much cheaper to build and it requires qualified welders, etc. and extensive nondestructive testing and inspection of metals, welds and castings. Of all the techniques radiography is widely used for concrete

  10. Concrete deck material properties.

    Science.gov (United States)

    2009-01-01

    The two-fold focus of this study was (a) to develop an understanding of the mechanisms responsible for causing : cracking in the concrete; and (b) to study the influence of the local materials on the performance of NYSDOTs HP : concrete mixture. R...

  11. Concrete-Design

    Directory of Open Access Journals (Sweden)

    Leczovics Péter

    2014-12-01

    Full Text Available Present paper introduces a new interpretation of concrete, demonstrating some extreme possibilities of this rigid material such as a design element. In the first part a brief overview of the previous achievements are shown. The second part of this paper focuses on the relationship between concrete and fashion.

  12. Danish High Performance Concretes

    DEFF Research Database (Denmark)

    Nielsen, M. P.; Christoffersen, J.; Frederiksen, J.

    1994-01-01

    In this paper the main results obtained in the research program High Performance Concretes in the 90's are presented. This program was financed by the Danish government and was carried out in cooperation between The Technical University of Denmark, several private companies, and Aalborg University...... concretes, workability, ductility, and confinement problems....

  13. Concrete, hardened: Self desiccation

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard; Persson, Bertil

    1999-01-01

    The test method covers the determination of internal relative humidity (RH) in hardened concrete and cement mortar using RH instruments. The determination of RH is done on crushed samples of concrete or cement motar. This test method is only for measuring equipment which gives off or takes up...

  14. concrete5 Beginner's Guide

    CERN Document Server

    Laubacher, Remo

    2011-01-01

    This book is part of Packt's Beginner's Guide series. You will be guided through the set up of a Concrete5 site with step-by-step practical examples. This book is ideal for developers who would like to build their first site with Concrete5. Some k

  15. Application of advanced diffraction based optical metrology overlay capabilities for high-volume manufacturing

    Science.gov (United States)

    Chen, Kai-Hsiung; Huang, Guo-Tsai; Hsieh, Hung-Chih; Ni, Wei-Feng; Chuang, S. M.; Chuang, T. K.; Ke, Chih-Ming; Huang, Jacky; Rao, Shiuan-An; Cumurcu Gysen, Aysegul; d'Alfonso, Maxime; Yueh, Jenny; Izikson, Pavel; Soco, Aileen; Wu, Jon; Nooitgedagt, Tjitte; Ottens, Jeroen; Kim, Yong Ho; Ebert, Martin

    2017-03-01

    On-product overlay requirements are becoming more challenging with every next technology node due to the continued decrease of the device dimensions and process tolerances. Therefore, current and future technology nodes require demanding metrology capabilities such as target designs that are robust towards process variations and high overlay measurement density (e.g. for higher order process corrections) to enable advanced process control solutions. The impact of advanced control solutions based on YieldStar overlay data is being presented in this paper. Multi patterning techniques are applied for critical layers and leading to additional overlay measurement demands. The use of 1D process steps results in the need of overlay measurements relative to more than one layer. Dealing with the increased number of overlay measurements while keeping the high measurement density and metrology accuracy at the same time presents a challenge for high volume manufacturing (HVM). These challenges are addressed by the capability to measure multi-layer targets with the recently introduced YieldStar metrology tool, YS350. On-product overlay results of such multi-layers and standard targets are presented including measurement stability performance.

  16. Radiation shielding concrete

    International Nuclear Information System (INIS)

    Kunishima, Shigeru.

    1990-01-01

    The radiation shielding concretes comprise water, cement, fine aggregates consisting of serpentines and blown mist slags, coarse aggregates consisting of serpentines and kneading materials. Since serpentines containing a relatively great amount of water of crystallization in rocks as coarse aggregates and fine aggregates, the hydrogen content in the radiation shielding concretes is increased and the neutron shielding effect is improved. In addition, since serpentines are added as the fine aggregates and blown mists slags of a great specific gravity are used, the specific gravity of the shielding concretes is increased to improve the γ-ray shielding effect. Further, by the use of the kneading material having a water reducing effect and fluidizing effect, and by the bearing effect of the spherical blown mist slags used as the fine aggregates, concrete fluidity can be increased. Accordingly, workability of the radiation shielding concretes can be improved. (T.M.)

  17. Concrete quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Holz, N. [Harza Engineering Company, Chicago, IL (United States)

    2000-08-01

    This short article reports on progress at the world's largest civil construction project, namely China's Three Gorges hydro project. Work goes on around the clock to put in place nearly 28 M m{sup 3} of concrete. At every stage of the work there is strong emphasis on quality assurance (QA) and concrete is no exception. The US company Harza Engineering has been providing QA since the mid-1980s and concrete QA has been based on international standards. Harza personnel work in the field with supervisors developing educational tools for supervising concrete construction and quality, as well as providing training courses in concrete technology. Some details on flood control, capacity, water quality and environmental aspects are given..

  18. Evaluation and Repair of Concrete Structures: Annotated Bibliography 1978 - 1988. Volume 2. (Repair, Evaluation, Maintenance and Rehabilitation Research Program)

    Science.gov (United States)

    1991-06-01

    steps at the Rugby Football Union Ground in Twickenham, England. The deteriorated steps were cut away from the existing steel support beams. Reinforcing...otherwise distorted b1 ._U.-.ious -pavements. Overlaying-can also improve skid resistance or ridei llity. flowever, -no one treatment is-a cure-all for all...MASS CONCRETE-A-l2, A-332,-B-403 Crack width B1 -6, B3-150, B-156, -MEMBRANES B3-311, B-346, C-261, B3-180 C-28-6, C-359-, C-396, C-420, C-464, Density

  19. Holistic metrology qualification extension and its application to characterize overlay targets with asymmetric effects

    Science.gov (United States)

    Dos Santos Ferreira, Olavio; Sadat Gousheh, Reza; Visser, Bart; Lie, Kenrick; Teuwen, Rachel; Izikson, Pavel; Grzela, Grzegorz; Mokaberi, Babak; Zhou, Steve; Smith, Justin; Husain, Danish; Mandoy, Ram S.; Olvera, Raul

    2018-03-01

    Ever increasing need for tighter on-product overlay (OPO), as well as enhanced accuracy in overlay metrology and methodology, is driving semiconductor industry's technologists to innovate new approaches to OPO measurements. In case of High Volume Manufacturing (HVM) fabs, it is often critical to strive for both accuracy and robustness. Robustness, in particular, can be challenging in metrology since overlay targets can be impacted by proximity of other structures next to the overlay target (asymmetric effects), as well as symmetric stack changes such as photoresist height variations. Both symmetric and asymmetric contributors have impact on robustness. Furthermore, tweaking or optimizing wafer processing parameters for maximum yield may have an adverse effect on physical target integrity. As a result, measuring and monitoring physical changes or process abnormalities/artefacts in terms of new Key Performance Indicators (KPIs) is crucial for the end goal of minimizing true in-die overlay of the integrated circuits (ICs). IC manufacturing fabs often relied on CD-SEM in the past to capture true in-die overlay. Due to destructive and intrusive nature of CD-SEMs on certain materials, it's desirable to characterize asymmetry effects for overlay targets via inline KPIs utilizing YieldStar (YS) metrology tools. These KPIs can also be integrated as part of (μDBO) target evaluation and selection for final recipe flow. In this publication, the Holistic Metrology Qualification (HMQ) flow was extended to account for process induced (asymmetric) effects such as Grating Imbalance (GI) and Bottom Grating Asymmetry (BGA). Local GI typically contributes to the intrafield OPO whereas BGA typically impacts the interfield OPO, predominantly at the wafer edge. Stack height variations highly impact overlay metrology accuracy, in particular in case of multi-layer LithoEtch Litho-Etch (LELE) overlay control scheme. Introducing a GI impact on overlay (in nm) KPI check quantifies the

  20. Concrete sample point: 304 Concretion Facility

    International Nuclear Information System (INIS)

    Rollison, M.D.

    1995-01-01

    This report contains information concerning the analysis of concretes for volatile organic compounds. Included are the raw data for these analysis and the quality control data, the standards data, and all of the accompanying chains-of-custody records and requests for special analysis

  1. Performance of Waterless Concrete

    Science.gov (United States)

    Toutanji, Houssam; Evans, Steve; Grugel, Richard N.

    2010-01-01

    The development of permanent lunar bases is constrained by performance of construction materials and availability of in-situ resources. Concrete seems a suitable construction material for the lunar environment, but water, one of its major components, is an extremely scarce resource on the Moon. This study explores an alternative to hydraulic concrete by replacing the binding mix of concrete (cement and water) with sulfur. Sulfur is a volatile element on the lunar surface that can be extracted from lunar soils by heating. Sulfur concrete mixes were prepared to investigate the effect of extreme environmental conditions on the properties of sulfur concrete. A hypervelocity impact test was conducted, having as its target a 5-cm cubic sample of sulfur concrete. This item consisted of JSC-1 lunar regolith simulant (65%) and sulfur (35%). The sample was placed in the MSFC Impact Test Facility s Micro Light Gas Gun target chamber, and was struck by a 1-mm diameter (1.4e-03 g) aluminum projectile at 5.85 km/s. In addition, HZTERN code, provided by NASA was used to study the effectiveness of sulfur concrete when subjected to space radiation.

  2. Electrokinetic decontamination of concrete

    International Nuclear Information System (INIS)

    Lomasney, H.L.; SenGupta, A.K.; Yachmenev, V.

    1996-01-01

    ELECTROSORB Electrokinetic Extraction Technology, developed by ISOTRON Corp., offers a cost-effective approach to treating contaminated concrete. Heavy metals/radionuclides trapped in concrete can be extracted using this process if they are chemically solubilized; solubilizers used are citric acid alone and a mixture of citric and nitric acids. A DC electric field is applied across the contaminated concrete to electrokinetically transport the solubilized contaminants from the concrete pores to a collector on the concrete surface. The collector is an extraction pad laid on the surface. The pad provides confinement for a planar electrode and solubilizer solution; it is operated under a vacuum to hold the pad against the concrete surface. Operation requires little attendance, reducing the workers' health hazards. The process incorporates a mechanism for recycling the solubilizer solution. A field demonstration of the process took place in Building 21 of DOE's Mound facility in Miamisburg, OH, over 12 days in June 1996. The thorium species present in this building's concrete floors included ThO 2 and thorium oxalate. The nitric acid was found to facilitate Th extraction

  3. Steel fiber reinforced concrete

    International Nuclear Information System (INIS)

    Baloch, S.U.

    2005-01-01

    Steel-Fiber Reinforced Concrete is constructed by adding short fibers of small cross-sectional size .to the fresh concrete. These fibers reinforce the concrete in all directions, as they are randomly oriented. The improved mechanical properties of concrete include ductility, impact-resistance, compressive, tensile and flexural strength and abrasion-resistance. These uniqlte properties of the fiber- reinforcement can be exploited to great advantage in concrete structural members containing both conventional bar-reinforcement and steel fibers. The improvements in mechanical properties of cementitious materials resulting from steel-fiber reinforcement depend on the type, geometry, volume fraction and material-properties of fibers, the matrix mix proportions and the fiber-matrix interfacial bond characteristics. Effects of steel fibers on the mechanical properties of concrete have been investigated in this paper through a comprehensive testing-programme, by varying the fiber volume fraction and the aspect-ratio (Lid) of fibers. Significant improvements are observed in compressive, tensile, flexural strength and impact-resistance of concrete, accompanied by marked improvement in ductility. optimum fiber-volume fraction and aspect-ratio of steel fibers is identified. Test results are analyzed in details and relevant conclusions drawn. The research is finally concluded with future research needs. (author)

  4. Effect of insulating concrete forms in concrete compresive strength

    Science.gov (United States)

    Martinez Jerez, Silvio R.

    The subject presented in this thesis is the effect of Insulating Concrete Forms (ICF's) on concrete compressive strength. This work seeks to identify if concrete cured in ICF's has an effect in compressive strength due to the thermal insulation provided by the forms. Modern construction is moving to energy efficient buildings and ICF's is becoming more popular in new developments. The thesis used a concrete mixture and a mortar mixture to investigate the effects of ICF's on concrete compressive strength. After the experimentations were performed, it was concluded that the ICF's do affect concrete strength. It was found that the forms increase concrete strength without the need for additional curing water. An increase of 50% in strength at 56 days was obtained. It was concluded that the longer concrete cures inside ICF's, the higher strength it reaches, and that ICF's effect on concrete strength is proportional to volume of concrete.

  5. Concrete and criticality

    International Nuclear Information System (INIS)

    Carter, R.D.

    1978-01-01

    Concrete is a widely used structural material which occurs frequently in systems requiring criticality analyses. Ordinarily, we give little thought to what its actual composition is (as compared to reference compositions), yet in criticality safety, differences in composition can cause large changes in k-effective and it may not be easy to predict in which direction the change will occur. Concrete composition is quite variable with differences in the aggregate used in the concrete in various parts of the country providing relative large differences in k-effective. The water content of concrete can also strongly affect the reactivity of a system in which it acts as a reflector or is interspersed between fissile units. Because concrete is so common and is often (but not always) a better reflector than water, one must know the concrete compositions or be prepared to use a ''worst case'' composition. It may be a problem, however, to determine just what is the worst case. At the Hanford Plant, the aggregate normally used is basalt, which gives a composition very low in carbon as opposed to those areas (e.g., Oak Ridge) where the use of limestone aggregate will result in concrete with a high carbon content. The data presented show some of the effects found in situations using ''Hanford'' concrete, but similar effects might be found with other compositions. In some cases, the use of concrete may be incidental to the effects shown. While the numbers shown are those for actual systems, the primary intent is to alert the reader that these effects can occur. In applying this information, the analyst should use material specific to the systems being analyzed

  6. Biodecontamination of concrete

    International Nuclear Information System (INIS)

    Hamilton, M.A.; Rogers, R.D.; Benson, J.

    1996-01-01

    A novel technology for biologically decontaminating concrete is being jointly developed by scientists at the Idaho National Engineering Laboratory (INEL) and British Nuclear Fuels plc (BNFL). The technology exploits a naturally occurring phenomenon referred to as microbially influenced degradation (MID) in which bacteria produce acids that dissolve the cement matrix of concrete. Most radionuclide contamination of concrete is fixed in the outer few mm of the concrete surface. By capturing and controlling this natural process, a biological method of removing the surface of concrete to depths up to several mm is being developed. Three types of bacteria are known to be important in MID of concrete: nitrifying bacteria that produce nitric acid, sulfur oxidizing bacteria that produce sulfuric acid, and certain heterotrophic bacteria that produce organic acids. An investigation of natural environments demonstrated with scanning electron microscopy the presence of bacteria on concrete surfaces of a variety of structures, such as bridges and dams, where corrosion is evident. Enumeration of sulfur oxidizing and nitrifying bacteria revealed their presence and activity on structures to varying degrees in different environments. Under ideal conditions, Thiobacillus thiooxidans, a sulfur oxidizing bacteria, attached to and colonized the surface of concrete specimens. Over 1mm depth of material from a 10 cm x 10 cm square surface was removed in 68 days in the Thiobacillus treated specimen compared to a sterile control. Laboratory and field demonstrations are currently being conducted using experimental chambers designed to be mounted directly to concrete surfaces where radionuclide contamination exists. Data is being obtained in order to determine actual rates of surface removal and limitations to the system. This information will be used to develop a full scale decontamination technology

  7. concrete5 cookbook

    CERN Document Server

    Strack, David

    2013-01-01

    The Cookbook-style recipes allow you to go both directly to your topic of interest or follow topics throughout a chapter to gain in-depth knowledge. This practical Cookbook will cater to the needs of both intermediate and advanced concrete5 developers.This book is geared towards intermediate to advanced PHP developers who would like to learn more about the concrete5 content management system. Developers already familiar with concrete5 will learn new time-saving tricks and will find the book to be a great reference tool.

  8. Concrete = aggregate, cement, water?

    International Nuclear Information System (INIS)

    Jelinek, J.

    1990-01-01

    Concrete for the Temelin nuclear power plant is produced to about 70 different formulae. For quality production, homogeneous properties of aggregates, accurate proportioning devices, technological discipline and systematic inspections and tests should be assured. The results are reported of measuring compression strength after 28 days for different concrete samples. The results of such tests allow reducing the proportion of cement, which brings about considerable savings. Reduction in cement quantities can also be achieved by adding ash to the concrete mixes. Ligoplast, a plasticizer addition is used for improving workability. (M.D). 8 figs

  9. Properties of high-workability concrete with recycled concrete aggregate

    OpenAIRE

    Safiuddin,; Alengaram,Ubagaram Johnson; Salam,Abdus; Jumaat,Mohd Zamin; Jaafar,Fahrol Fadhli; Saad,Hawa Binti

    2011-01-01

    This study presents the effects of recycled concrete aggregate (RCA) on the key fresh and hardened properties of concrete. RCA was used to produce high-workability concrete substituting 0-100% natural coarse aggregate (NCA) by weight. The slump and slump flow of fresh concretes were determined to ensure high workability. In addition, the compressive, flexural and splitting tensile strengths, modulus of elasticity, and permeable voids of hardened concretes were determined. The test results rev...

  10. COMPARATIVE STUDY OF GLASS FIBRE CONCRETE AND NORMAL CONCRETE

    OpenAIRE

    Mr.Yogesh S.Lanjewar*

    2018-01-01

    Concrete is basically the most important material concerning with the construction and infrastructural procedures, for which it should be of good strength and durability. Many researches are being conducted to make concrete more sustainable and of more strength and durability. Therefore keeping this in mind i have chosen to do the comparative study regarding the strength of normal concrete with the glass fibre added concrete using mix design procedure as per IS 10262-2009 for concrete. As w...

  11. Electrokenitic Corrosion Treatment of Concrete

    Science.gov (United States)

    Cardenas, Henry E (Inventor)

    2015-01-01

    A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

  12. Electrokinetic Strength Enhancement of Concrete

    Science.gov (United States)

    Cardenas, Henry E. (Inventor)

    2016-01-01

    A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

  13. Shrinkage Reducing Admixture for Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Concrete shrinkage cracking is a common problem in all types of concrete structures, especially for structures and environments where the cracks are prevalent and the repercussions are most severe. A liquid shrinkage reducing admixture for concrete, developed by GRACE Construction Products and ARCO Chemical Company, that reduces significantly the shrinkage during concrete drying and potentially reduces overall cracking over time.

  14. 64nm pitch metal1 double patterning metrology: CD and OVL control by SEMCD, image based overlay and diffraction based overlay

    Science.gov (United States)

    Ducoté, Julien; Dettoni, Florent; Bouyssou, Régis; Le-Gratiet, Bertrand; Carau, Damien; Dezauzier, Christophe

    2015-03-01

    Patterning process control of advanced nodes has required major changes over the last few years. Process control needs of critical patterning levels since 28nm technology node is extremely aggressive showing that metrology accuracy/sensitivity must be finely tuned. The introduction of pitch splitting (Litho-Etch-Litho-Etch) at 14FDSOInm node requires the development of specific metrologies to adopt advanced process control (for CD, overlay and focus corrections). The pitch splitting process leads to final line CD uniformities that are a combination of the CD uniformities of the two exposures, while the space CD uniformities are depending on both CD and OVL variability. In this paper, investigations of CD and OVL process control of 64nm minimum pitch at Metal1 level of 14FDSOI technology, within the double patterning process flow (Litho, hard mask etch, line etch) are presented. Various measurements with SEMCD tools (Hitachi), and overlay tools (KT for Image Based Overlay - IBO, and ASML for Diffraction Based Overlay - DBO) are compared. Metrology targets are embedded within a block instanced several times within the field to perform intra-field process variations characterizations. Specific SEMCD targets were designed for independent measurement of both line CD (A and B) and space CD (A to B and B to A) for each exposure within a single measurement during the DP flow. Based on those measurements correlation between overlay determined with SEMCD and with standard overlay tools can be evaluated. Such correlation at different steps through the DP flow is investigated regarding the metrology type. Process correction models are evaluated with respect to the measurement type and the intra-field sampling.

  15. RelEx: Visualization for Actively Changing Overlay Network Specifications.

    Science.gov (United States)

    Sedlmair, M; Frank, A; Munzner, T; Butz, A

    2012-12-01

    We present a network visualization design study focused on supporting automotive engineers who need to specify and optimize traffic patterns for in-car communication networks. The task and data abstractions that we derived support actively making changes to an overlay network, where logical communication specifications must be mapped to an underlying physical network. These abstractions are very different from the dominant use case in visual network analysis, namely identifying clusters and central nodes, that stems from the domain of social network analysis. Our visualization tool RelEx was created and iteratively refined through a full user-centered design process that included a full problem characterization phase before tool design began, paper prototyping, iterative refinement in close collaboration with expert users for formative evaluation, deployment in the field with real analysts using their own data, usability testing with non-expert users, and summative evaluation at the end of the deployment. In the summative post-deployment study, which entailed domain experts using the tool over several weeks in their daily practice, we documented many examples where the use of RelEx simplified or sped up their work compared to previous practices.

  16. Quality metric for accurate overlay control in <20nm nodes

    Science.gov (United States)

    Klein, Dana; Amit, Eran; Cohen, Guy; Amir, Nuriel; Har-Zvi, Michael; Huang, Chin-Chou Kevin; Karur-Shanmugam, Ramkumar; Pierson, Bill; Kato, Cindy; Kurita, Hiroyuki

    2013-04-01

    The semiconductor industry is moving toward 20nm nodes and below. As the Overlay (OVL) budget is getting tighter at these advanced nodes, the importance in the accuracy in each nanometer of OVL error is critical. When process owners select OVL targets and methods for their process, they must do it wisely; otherwise the reported OVL could be inaccurate, resulting in yield loss. The same problem can occur when the target sampling map is chosen incorrectly, consisting of asymmetric targets that will cause biased correctable terms and a corrupted wafer. Total measurement uncertainty (TMU) is the main parameter that process owners use when choosing an OVL target per layer. Going towards the 20nm nodes and below, TMU will not be enough for accurate OVL control. KLA-Tencor has introduced a quality score named `Qmerit' for its imaging based OVL (IBO) targets, which is obtained on the-fly for each OVL measurement point in X & Y. This Qmerit score will enable the process owners to select compatible targets which provide accurate OVL values for their process and thereby improve their yield. Together with K-T Analyzer's ability to detect the symmetric targets across the wafer and within the field, the Archer tools will continue to provide an independent, reliable measurement of OVL error into the next advanced nodes, enabling fabs to manufacture devices that meet their tight OVL error budgets.

  17. ATLAS Simulation using Real Data: Embedding and Overlay

    Science.gov (United States)

    Haas, Andrew; ATLAS Collaboration

    2017-10-01

    For some physics processes studied with the ATLAS detector, a more accurate simulation in some respects can be achieved by including real data into simulated events, with substantial potential improvements in the CPU, disk space, and memory usage of the standard simulation configuration, at the cost of significant database and networking challenges. Real proton-proton background events can be overlaid (at the detector digitization output stage) on a simulated hard-scatter process, to account for pileup background (from nearby bunch crossings), cavern background, and detector noise. A similar method is used to account for the large underlying event from heavy ion collisions, rather than directly simulating the full collision. Embedding replaces the muons found in Z→μμ decays in data with simulated taus at the same 4-momenta, thus preserving the underlying event and pileup from the original data event. In all these cases, care must be taken to exactly match detector conditions (beamspot, magnetic fields, alignments, dead sensors, etc.) between the real data event and the simulation. We will discuss the status of these overlay and embedding techniques within ATLAS software and computing.

  18. Augmented Endoscopic Images Overlaying Shape Changes in Bone Cutting Procedures.

    Science.gov (United States)

    Nakao, Megumi; Endo, Shota; Nakao, Shinichi; Yoshida, Munehito; Matsuda, Tetsuya

    2016-01-01

    In microendoscopic discectomy for spinal disorders, bone cutting procedures are performed in tight spaces while observing a small portion of the target structures. Although optical tracking systems are able to measure the tip of the surgical tool during surgery, the poor shape information available during surgery makes accurate cutting difficult, even if preoperative computed tomography and magnetic resonance images are used for reference. Shape estimation and visualization of the target structures are essential for accurate cutting. However, time-varying shape changes during cutting procedures are still challenging issues for intraoperative navigation. This paper introduces a concept of endoscopic image augmentation that overlays shape changes to support bone cutting procedures. This framework handles the history of the location of the measured drill tip as a volume label and visualizes the remains to be cut overlaid on the endoscopic image in real time. A cutting experiment was performed with volunteers, and the feasibility of this concept was examined using a clinical navigation system. The efficacy of the cutting aid was evaluated with respect to the shape similarity, total moved distance of a cutting tool, and required cutting time. The results of the experiments showed that cutting performance was significantly improved by the proposed framework.

  19. Driving imaging and overlay performance to the limits with advanced lithography optimization

    Science.gov (United States)

    Mulkens, Jan; Finders, Jo; van der Laan, Hans; Hinnen, Paul; Kubis, Michael; Beems, Marcel

    2012-03-01

    Immersion lithography is being extended to 22-nm and even below. Next to generic scanner system improvements, application specific solutions are needed to follow the requirements for CD control and overlay. Starting from the performance budgets, this paper discusses how to improve (in volume manufacturing environment) CDU towards 1-nm and overlay towards 3-nm. The improvements are based on deploying the actuator capabilities of the immersion scanner. The latest generation immersion scanners have extended the correction capabilities for overlay and imaging, offering freeform adjustments of lens, illuminator and wafer grid. In order to determine the needed adjustments the recipe generation per user application is based on a combination wafer metrology data and computational lithography methods. For overlay, focus and CD metrology we use an angle resolved optical scatterometer.

  20. Texas flexible pavements and overlays : calibration plans for M-E models and related software.

    Science.gov (United States)

    2013-06-01

    This five-year project was initiated to collect materials and pavement performance data on a minimum of 100 highway test sections around the State of Texas, incorporating flexible pavements and overlays. Besides being used to calibrate and validate m...

  1. Digitizing geographic data with GRIDOT; a generalized program for drawing overlay grids in various map projections

    International Nuclear Information System (INIS)

    Edwards, R.G.; Durfee, R.C.

    1976-09-01

    The GRIDOT computer program draws overlay grids on a Calcomp plotter for use in digitizing information from maps, rectified aerial photographs, and other sources of spatially distributed data related to regional environmental problems. The options of the program facilitate use of the overlays with standard maps and map projections of the continental United States. The overlay grid may be defined as a latitude-longitude grid (geodetic grid), a Universal Transverse Mercator Grid, or one of the standard state-plane coordinate system grids. The map for which the overlay is intended may be in an Albers Equal Area projection, a Lambert Conformal projection, a Polyconic projection, a Transverse Mercator projection, a Universal Transverse Mercator projection, or any of the standard state-plane projections

  2. A historical examination of concrete

    International Nuclear Information System (INIS)

    Mallinson, L.G.; Li Davies, I.

    1987-01-01

    The requirement that concrete in radioactive waste repositories be stable physically and chemically for very long times has initiated studies of ancient and old concretes. This report is a contribution to this effort. After a description of the history of cement and concrete, the published literature relating to the analysis of old and ancient concrete is reviewed. A series of samples spanning the history of concrete has been obtained; a variety of physical and chemical techniques have been employed to characterize these samples. Reasons for survival of ancient concretes, and for durability of early, reinforced concretes are identified. Recommendations for further studies are given. 132 refs

  3. Integrated scatterometry for tight overlay and CD control to enable 20-nm node wafer manufacturing.

    Science.gov (United States)

    Benschop, Jos; Engelen, Andre; Cramer, Hugo; Kubis, Michael; Hinnen, Paul; van der Laan, Hans; Bhattacharyya, Kaustuve; Mulkens, Jan

    2013-04-01

    The overlay, CDU and focus requirements for the 20nm node can only be met using a holistic lithography approach whereby full use is made of high-order, field-by-field, scanner correction capabilities. An essential element in this approach is a fast, precise and accurate in-line metrology sensor, capable to measure on product. The capabilities of the metrology sensor as well as the impact on overlay, CD and focus will be shared in this paper.

  4. Analysis of mechanical tensile properties of irradiated and annealed RPV weld overlay cladding

    Energy Technology Data Exchange (ETDEWEB)

    Novak, J [Czech Nuclear Society, Prague (Czech Republic)

    1994-12-31

    Mechanical tensile properties of irradiated and annealed outer layer of reactor pressure vessel weld overlay cladding, composed of Cr19Ni10Nb alloy, have been experimentally determined by conventional tensile testing and indentation testing. The constitutive properties of weld overlay cladding are then modelled with two homogenization models of the constitutive properties of elastic-plastic matrix-inclusion composites; numerical and experimental results are then compared. 10 refs., 4 figs., 4 tabs.

  5. On cooperative and efficient overlay network evolution based on a group selection pattern.

    Science.gov (United States)

    Nakao, Akihiro; Wang, Yufeng

    2010-04-01

    In overlay networks, the interplay between network structure and dynamics remains largely unexplored. In this paper, we study dynamic coevolution between individual rational strategies (cooperative or defect) and the overlay network structure, that is, the interaction between peer's local rational behaviors and the emergence of the whole network structure. We propose an evolutionary game theory (EGT)-based overlay topology evolution scheme to drive a given overlay into the small-world structure (high global network efficiency and average clustering coefficient). Our contributions are the following threefold: From the viewpoint of peers' local interactions, we explicitly consider the peer's rational behavior and introduce a link-formation game to characterize the social dilemma of forming links in an overlay network. Furthermore, in the evolutionary link-formation phase, we adopt a simple economic process: Each peer keeps one link to a cooperative neighbor in its neighborhood, which can slightly speed up the convergence of cooperation and increase network efficiency; from the viewpoint of the whole network structure, our simulation results show that the EGT-based scheme can drive an arbitrary overlay network into a fully cooperative and efficient small-world structure. Moreover, we compare our scheme with a search-based economic model of network formation and illustrate that our scheme can achieve the experimental and analytical results in the latter model. In addition, we also graphically illustrate the final overlay network structure; finally, based on the group selection model and evolutionary set theory, we theoretically obtain the approximate threshold of cost and draw the conclusion that the small value of the average degree and the large number of the total peers in an overlay network facilitate the evolution of cooperation.

  6. Analysis of mechanical tensile properties of irradiated and annealed RPV weld overlay cladding

    International Nuclear Information System (INIS)

    Novak, J.

    1993-01-01

    Mechanical tensile properties of irradiated and annealed outer layer of reactor pressure vessel weld overlay cladding, composed of Cr19Ni10Nb alloy, have been experimentally determined by conventional tensile testing and indentation testing. The constitutive properties of weld overlay cladding are then modelled with two homogenization models of the constitutive properties of elastic-plastic matrix-inclusion composites; numerical and experimental results are then compared. 10 refs., 4 figs., 4 tabs

  7. Effect of SiO2 Overlayer on WO3 Sensitivity to Ammonia

    Directory of Open Access Journals (Sweden)

    Vibha Srivastava

    2010-06-01

    Full Text Available Ammonia gas sensing properties of tungsten trioxide thick film sensor was investigated. The doping of noble catalysts such as Pt, Pd, Au enhanced the gas sensitivity. Platinum doping was found to result in highest sensitivity. Remarkable sensitivity enhancement was realized by coating WO3 thick film sensors with SiO2 overlayer. Sol gel process derived silica overlayer increased ammonia gas sensitivity for doped as well as undoped sensor.

  8. Anchorage in concrete construction

    CERN Document Server

    Eligehausen, Rolf; Silva, John F

    2013-01-01

    A comprehensive treatment of current fastening technology using inserts (anchor channels, headed stud), anchors (metal expansion anchor, undercut anchor, bonded anchor, concrete screw and plastic anchor) as well as power actuated fasteners in concrete. It describes in detail the fastening elements as well as their effects and load-bearing capacities in cracked and non-cracked concrete. It further focuses on corrosion behaviour, fire resistance and characteristics with earthquakes and shocks. It finishes off with the design of fastenings according to the European Technical Approval Guideline (ETAG 001), the Final Draft of the CEN Technical Specification 'Design of fastenings for use in concrete' and the American Standards ACI 318-05, Appendix D and ACI 349-01, Appendix B.

  9. Concrete Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This is a 20,000-sq ft laboratory that supports research on all aspects of concrete and materials technology. The staff of this facility offer wide-ranging expertise...

  10. Prestressed concrete design

    CERN Document Server

    Hurst, MK

    1998-01-01

    This edition provides up-to-date guidance on the detailed design of prestressed concrete structures. All major topics are dealt with, including prestressed flat slabs, an important and growing application in the design of buildings.

  11. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    TECS

    exposure to water and salt attack by replacing 10% magnesium chloride solution by magnesium sulphate solution ... Having tremendous load bearing capacity, it can withstand .... retention coefficients for similar concrete compositions.

  12. Concrete decontamination scoping tests

    International Nuclear Information System (INIS)

    Archibald, K.E.

    1995-01-01

    This report details the research efforts and scoping tests performed at the Idaho Chemical Process Plant using scabbling, chemical, and electro-osmotic decontamination techniques on radiologically contaminated concrete

  13. Modeling reinforced concrete durability.

    Science.gov (United States)

    2014-06-01

    This project developed a next-generation modeling approach for projecting the extent of : reinforced concrete corrosion-related damage, customized for new and existing Florida Department of : Transportation bridges and suitable for adapting to broade...

  14. Recycling of concrete

    International Nuclear Information System (INIS)

    Halaszovich, S.

    1988-01-01

    The paper reviews potentials and problems of disposal or recycling of concrete removed from nuclear installations. Due to the difficulties in determining radioactivity limits that are compatible with utilization of recycled material in practice, a method is proposed that takes into account inhalation of dusts, as occurring during the reprocessing or recycling of the concrete, for instance in road building. This method is based on the maximum permissible radioactivity uptake by inhalation of a nuclide mixture of unknown composition. (RB) [de

  15. Sulfur polymer cement concrete

    International Nuclear Information System (INIS)

    Weber, H.H.; McBee, W.C.

    1990-01-01

    Sulfur-based composite materials formulated using sulfur polymer cement (SPC) and mineral aggregates are described and compared with conventional portland cement based materials. Materials characteristics presented include mechanical strength, chemical resistance, impact resistance, moisture permeation, and linear shrinkage during placement and curing. Examples of preparation and placement of sulfur polymer cement concrete (SC) are described using commercial scale equipment. SC applications presented are focused into hostile chemical environments where severe portland cement concrete (PCC) failure has occurred

  16. ADVANCEMENTS IN CONCRETE TECHNOLOGY

    OpenAIRE

    Shri Purvansh B. Shah; Shri Prakash D. Gohil; Shri Hiren J. Chavda; Shri Tejas D. Khediya

    2015-01-01

    Developing and maintaining world’s infrastructure to meet the future needs of industrialized and developing countries is necessary to economically grow and improve the quality of life. The quality and performance of concrete plays a key role for most of infrastructure including commercial, industrial, residential and military structures, dams, power plants. Concrete is the single largest manufactured material in the world and accounts for more than 6 billion metric tons of materials annual...

  17. VMCast: A VM-Assisted Stability Enhancing Solution for Tree-Based Overlay Multicast.

    Directory of Open Access Journals (Sweden)

    Weidong Gu

    Full Text Available Tree-based overlay multicast is an effective group communication method for media streaming applications. However, a group member's departure causes all of its descendants to be disconnected from the multicast tree for some time, which results in poor performance. The above problem is difficult to be addressed because overlay multicast tree is intrinsically instable. In this paper, we proposed a novel stability enhancing solution, VMCast, for tree-based overlay multicast. This solution uses two types of on-demand cloud virtual machines (VMs, i.e., multicast VMs (MVMs and compensation VMs (CVMs. MVMs are used to disseminate the multicast data, whereas CVMs are used to offer streaming compensation. The used VMs in the same cloud datacenter constitute a VM cluster. Each VM cluster is responsible for a service domain (VMSD, and each group member belongs to a specific VMSD. The data source delivers the multicast data to MVMs through a reliable path, and MVMs further disseminate the data to group members along domain overlay multicast trees. The above approach structurally improves the stability of the overlay multicast tree. We further utilized CVM-based streaming compensation to enhance the stability of the data distribution in the VMSDs. VMCast can be used as an extension to existing tree-based overlay multicast solutions, to provide better services for media streaming applications. We applied VMCast to two application instances (i.e., HMTP and HCcast. The results show that it can obviously enhance the stability of the data distribution.

  18. Approaches of multilayer overlay process control for 28nm FD-SOI derivative applications

    Science.gov (United States)

    Duclaux, Benjamin; De Caunes, Jean; Perrier, Robin; Gatefait, Maxime; Le Gratiet, Bertrand; Chapon, Jean-Damien; Monget, Cédric

    2018-03-01

    Derivative technology like embedded Non-Volatile Memories (eNVM) is raising new types of challenges on the "more than Moore" path. By its construction: overlay is critical across multiple layers, by its running mode: usage of high voltage are stressing leakages and breakdown, and finally with its targeted market: Automotive, Industry automation, secure transactions… which are all requesting high device reliability (typically below 1ppm level). As a consequence, overlay specifications are tights, not only between one layer and its reference, but also among the critical layers sharing the same reference. This work describes a broad picture of the key points for multilayer overlay process control in the case of a 28nm FD-SOI technology and its derivative flows. First, the alignment trees of the different flow options have been optimized using a realistic process assumptions calculation for indirect overlay. Then, in the case of a complex alignment tree involving heterogeneous scanner toolset, criticality of tool matching between reference layer and critical layers of the flow has been highlighted. Improving the APC control loops of these multilayer dependencies has been studied with simulations of feed-forward as well as implementing new rework algorithm based on multi-measures. Finally, the management of these measurement steps raises some issues for inline support and using calculations or "virtual overlay" could help to gain some tool capability. A first step towards multilayer overlay process control has been taken.

  19. Performance of "Waterless Concrete"

    Science.gov (United States)

    Toutanji, H. A.; Grugel, R. N.

    2009-01-01

    Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in a lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and, by oxidation of the soil, iron and sulfur can be produced. Sulfur concrete specimens were cycled between liquid nitrogen (approx.]91 C) and room temperature (^21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (^21 C) and ^-101 C. Test results showed that due to temperature cycling, the compressive strength of cycled specimens was 20% of those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibres. The lunar regolith simulant was melted in a 25 cc Pt- Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to i hour. Glass fibres and small rods were pulled from the melt. The glass fibres were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Beams strengthened with glass fibres showed to exhibit an increase in the flexural strength by as much as 45%.

  20. Fracture Mechanics of Concrete

    DEFF Research Database (Denmark)

    Ulfkjær, Jens Peder

    Chapter 1 Chapter l contains the introduction to this thesis. The scope of the thesis is partly to investigate different numerical and analytical models based on fracture mechanical ideas, which are able to predict size effects, and partly to perform an experimental investigation on high-strength......Chapter 1 Chapter l contains the introduction to this thesis. The scope of the thesis is partly to investigate different numerical and analytical models based on fracture mechanical ideas, which are able to predict size effects, and partly to perform an experimental investigation on high......-strength concrete. Chapter 2 A description of the factors which influence the strength and cracking of concrete and high strength concrete is made. Then basic linear fracture mechanics is outlined followed by a description and evaluation of the models used to describe concrete fracture in tension. The chapter ends...... and the goveming equations are explicit and simple. These properties of the model make it a very powerful tool, which is applicable for the designing engineer. The method is also extended to reinforced concrete, where the results look very promising. The large experimental investigation on high-strength concrete...

  1. Fibre-concrete container

    International Nuclear Information System (INIS)

    2000-01-01

    In this leaflet the fibre-concrete container for radioactive wastes is described. The fibre container is made of fibre-concrete that contains cement, aggregate, sand, filter, flame-silica, super-plastificator, water and scattered metal fibres. The fibre-concrete container has a dice shape with outer dimension 1.7 x 1.7 x 1.7 m. It is mounted of a container body, a container cover and two caps. Total weight of container is 4,240 kg, maximum weight of loaded container do not must exceed 15,000 kg. The physical and mechanical properties of the fibre-concrete container are described in detail. The fibre-concrete container manufactured for storing of low and intermediate radioactive wastes. A fibre-concrete container utilization to store of radioactive wastes solves these problems: increase of stability of stored packages of radioactive waste; watertightness within 300 years at least; static stability of bearing space; better utilization of bearing spaces; insulation of radioactive waste in a case of seismic and geological event; increase of fire resistance; and transport of radioactive waste

  2. Concrete radiation shielding

    International Nuclear Information System (INIS)

    Kaplan, M.F.

    1989-01-01

    The increased use of nuclear energy has given rise to a growth in the amount of artificially produced radiation and radioactive materials. The design and construction of shielding to protect people, equipment and structures from the effects of radiation has never been more important. Experience has shown that concrete is an effective, versatile and economical material for the construction of radiation shielding. This book provides information on the principles governing the interaction of radiation with matter and on relevant nuclear physics to give the engineer an understanding of the design and construction of concrete shielding. It covers the physical, mechanical and nuclear properties of concrete; the effects of elevated temperatures and possible damage to concrete due to radiation; basic procedures for the design of concrete radiation shields and finally the special problems associated with their construction and cost. Although written primarily for engineers concerned with the design and construction of concrete shielding, the book also reviews the widely scattered data and information available on this subject and should therefore be of interest to students and those wishing to research further in this field. (author)

  3. Separation of contaminated concrete

    International Nuclear Information System (INIS)

    Bakiewicz, J.L.; Reymer, A.P.S.

    1990-01-01

    Separating the contaminated parts from the non-contaminated parts from decommissioned nuclear facilities may strongly reduce the amount of contaminated concrete. The reduction in volume of the radioactive contaminated concrete is dependent on how much cementstone is in the concrete. This research program shows that the radioactive contamination is mostly in the cementstone. However the choice that the cementstone parts, (or better said the radioactive parts) are smaller than 1 mm may not always be true. Normally the cementstone takes about 30% of the total concrete volume. A separation procedure composed by a combination of milling and thermal shock has been assessed. Both the cold and hot thermal shock in combination with milling are not able to separate the cementstone from the larger aggregates completely. However, the cementstone from the concrete with a low nominal grain size seems to be almost completely removed by the combination cold thermal shock/milling, while the cementstone from the concrete with a high nominal grain size seems to be almost completely removed by the combination hot thermal shock/milling. After both methods a layer of cementstone was still visible on the aggregates. Washing followed by a nitric acid treatment removed each 2 wt% of cementstone

  4. Offshore concrete structures

    International Nuclear Information System (INIS)

    Lamas Pardo, M.; Carral Couce, L. M.

    2011-01-01

    In the offshore industry there are two possible materials for the construction of the hull of a structure; the steel and concrete, with the first one widely used until now, as in the rest of the shiphuidling industry of merchant ships, warships, etc. Materials such as aluminum, GRP or timber areused in small units with lengths lower than 100 m, and in less adverse conditions than in the offshore industry. Nevertheless, some ships/barges have been built of concrete in the past, but have been rather isolated cases which have not changed the practice in the industry. In the First and Second World War were built by the scarcity of materials, while the series of barges by Alfred A. Yee was a rare exception. Other units were also made in concrete, but almost anecdotal. Still, the behaviour of these concrete structures, especially in terms of maintenance, has been excellent. Therefore, the fact that the concrete has not had an adequate reception so far in shipbuilding, does not mean that in will not be the material best suited for the offshore industry in the future. The extra displacement and associated fuel costs in concrete ships have been found prohibitive in the past. But the loss of mobility of a concrete hull in relation to a steel hull can be perfectly offset by the advantages offered by the concrete, as the shipping and offshore industry have very different priorities. One of the main differences in these priorities is in terms of maintenance and resistance to fatigue, precisely where the concrete performs better. ships can easily be dry docked for maintenance and repair, while in the offshore platforms these works have to be done in situ so maintenance and fatigue are crucial to them. Besides these, the concrete has other advantages according to findings of several studies. And although they are interested in the conclusions that the makes as they came from people in the concrete industry, the fact that in recent years concrete offshore unit shave been built

  5. Recycled Concrete as Aggregate for Structural Concrete Production

    Directory of Open Access Journals (Sweden)

    Mirjana Malešev

    2010-04-01

    Full Text Available A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC as a control concrete and two types of concrete made with natural fine and recycled coarse aggregate (50% and 100% replacement of coarse recycled aggregate. Ninety-nine specimens were made for the testing of the basic properties of hardened concrete. Load testing of reinforced concrete beams made of the investigated concrete types is also presented in the paper. Regardless of the replacement ratio, recycled aggregate concrete (RAC had a satisfactory performance, which did not differ significantly from the performance of control concrete in this experimental research. However, for this to be fulfilled, it is necessary to use quality recycled concrete coarse aggregate and to follow the specific rules for design and production of this new concrete type.

  6. A hybrid solution using computational prediction and measured data to accurately determine process corrections with reduced overlay sampling

    Science.gov (United States)

    Noyes, Ben F.; Mokaberi, Babak; Mandoy, Ram; Pate, Alex; Huijgen, Ralph; McBurney, Mike; Chen, Owen

    2017-03-01

    Reducing overlay error via an accurate APC feedback system is one of the main challenges in high volume production of the current and future nodes in the semiconductor industry. The overlay feedback system directly affects the number of dies meeting overlay specification and the number of layers requiring dedicated exposure tools through the fabrication flow. Increasing the former number and reducing the latter number is beneficial for the overall efficiency and yield of the fabrication process. An overlay feedback system requires accurate determination of the overlay error, or fingerprint, on exposed wafers in order to determine corrections to be automatically and dynamically applied to the exposure of future wafers. Since current and future nodes require correction per exposure (CPE), the resolution of the overlay fingerprint must be high enough to accommodate CPE in the overlay feedback system, or overlay control module (OCM). Determining a high resolution fingerprint from measured data requires extremely dense overlay sampling that takes a significant amount of measurement time. For static corrections this is acceptable, but in an automated dynamic correction system this method creates extreme bottlenecks for the throughput of said system as new lots have to wait until the previous lot is measured. One solution is using a less dense overlay sampling scheme and employing computationally up-sampled data to a dense fingerprint. That method uses a global fingerprint model over the entire wafer; measured localized overlay errors are therefore not always represented in its up-sampled output. This paper will discuss a hybrid system shown in Fig. 1 that combines a computationally up-sampled fingerprint with the measured data to more accurately capture the actual fingerprint, including local overlay errors. Such a hybrid system is shown to result in reduced modelled residuals while determining the fingerprint, and better on-product overlay performance.

  7. Improving overlay control through proper use of multilevel query APC

    Science.gov (United States)

    Conway, Timothy H.; Carlson, Alan; Crow, David A.

    2003-06-01

    Many state-of-the-art fabs are operating with increasingly diversified product mixes. For example, at Cypress Semiconductor, it is not unusual to be concurrently running multiple technologies and many devices within each technology. This diverse product mix significantly increases the difficulty of manually controlling overlay process corrections. As a result, automated run-to-run feedforward-feedback control has become a necessary and vital component of manufacturing. However, traditional run-to-run controllers rely on highly correlated historical events to forecast process corrections. For example, the historical process events typically are constrained to match the current event for exposure tool, device, process level and reticle ID. This narrowly defined process stream can result in insufficient data when applied to lowvolume or new-release devices. The run-to-run controller implemented at Cypress utilizes a multi-level query (Level-N) correlation algorithm, where each subsequent level widens the search criteria for available historical data. The paper discusses how best to widen the search criteria and how to determine and apply a known bias to account for tool-to-tool and device-to-device differences. Specific applications include offloading lots from one tool to another when the first tool is down for preventive maintenance, utilizing related devices to determine a default feedback vector for new-release devices, and applying bias values to account for known reticle-to-reticle differences. In this study, we will show how historical data can be leveraged from related devices or tools to overcome the limitations of narrow process streams. In particular, this paper discusses how effectively handling narrow process streams allows Cypress to offload lots from a baseline tool to an alternate tool.

  8. Usage of Crushed Concrete Fines in Decorative Concrete

    Science.gov (United States)

    Pilipenko, Anton; Bazhenova, Sofia

    2017-10-01

    The article is devoted to the questions of usage of crushed concrete fines from concrete scrap for the production of high-quality decorative composite materials based on mixed binder. The main problem in the application of crushed concrete in the manufacture of decorative concrete products is extremely low decorative properties of crushed concrete fines itself, as well as concrete products based on them. However, crushed concrete fines could have a positive impact on the structure of the concrete matrix and could improve the environmental and economic characteristics of the concrete products. Dust fraction of crushed concrete fines contains non-hydrated cement grains, which can be opened in screening process due to the low strength of the contact zone between the hydrated and non-hydrated cement. In addition, the screening process could increase activity of the crushed concrete fines, so it can be used as a fine aggregate and filler for concrete mixes. Previous studies have shown that the effect of the usage of the crushed concrete fines is small and does not allow to obtain concrete products with high strength. However, it is possible to improve the efficiency of the crushed concrete fines as a filler due to the complex of measures prior to mixing. Such measures may include a preliminary mechanochemical activation of the binder (cement binder, iron oxide pigment, silica fume and crushed concrete fines), as well as the usage of polycarboxylate superplasticizers. The development of specific surface area of activated crushed concrete fines ensures strong adhesion between grains of binder and filler during the formation of cement stone matrix. The particle size distribution of the crushed concrete fines could achieve the densest structure of cement stone matrix and improve its resistance to environmental effects. The authors examined the mechanisms of structure of concrete products with crushed concrete fines as a filler. The results of studies of the properties of

  9. Ultrasonic imaging in concrete

    International Nuclear Information System (INIS)

    Ribay, G.; Paris, O.; Rambach, J.M.

    2009-01-01

    The third and final protection barrier confining nuclear reactors is usually a concrete containment structure. Monitoring the structural integrity of these barriers is critical in ensuring the safety of nuclear power plants. The Institute for Radiological Protection and Nuclear Safety (IRSN) in France in collaboration with the French Atomic commission (CEA/LIST) has developed an ultrasonic phased-array technique capable of inspecting thick concrete walls. The non-destructive method is dedicated to detect cracks and bulk defects. Given the thickness of the structure (1.2 m) undergoing inspection and the heterogeneity of the concrete, the optimal frequency lies in the 50-300 kHz range. At these frequencies, the ultrasonic beam profiles are widespread (non-directive) with poor signal-to-noise ratio. Previous studies have shown the potential of using phased-array techniques (i.e., beam focusing and beam steering) in order to improve detection resolution and sizing accuracy. In this paper we present experimental studies performed with array up to 16 transducers working at 200 kHz. Experiments are carried out on representative concrete blocks containing artificial defects. One is a reinforced mock-up representative of the first reinforcing mesh of wall containment. Experimental results show that in spite of the reinforcement, artificial defects deep as half a meter can be detected. Reconstructed images resulting from phased array acquisitions on an artificial crack embedded in a concrete block are also presented and discussed. The presented method allows detecting oriented defects in concrete with improved signal to noise ratio and sensibility. A simulation model of the interaction of ultrasound with a heterogeneous medium like concrete is briefly commented. (authors)

  10. Using the overlay assay to qualitatively measure bacterial production of and sensitivity to pneumococcal bacteriocins.

    Science.gov (United States)

    Maricic, Natalie; Dawid, Suzanne

    2014-09-30

    Streptococcus pneumoniae colonizes the highly diverse polymicrobial community of the nasopharynx where it must compete with resident organisms. We have shown that bacterially produced antimicrobial peptides (bacteriocins) dictate the outcome of these competitive interactions. All fully-sequenced pneumococcal strains harbor a bacteriocin-like peptide (blp) locus. The blp locus encodes for a range of diverse bacteriocins and all of the highly conserved components needed for their regulation, processing, and secretion. The diversity of the bacteriocins found in the bacteriocin immunity region (BIR) of the locus is a major contributor of pneumococcal competition. Along with the bacteriocins, immunity genes are found in the BIR and are needed to protect the producer cell from the effects of its own bacteriocin. The overlay assay is a quick method for examining a large number of strains for competitive interactions mediated by bacteriocins. The overlay assay also allows for the characterization of bacteriocin-specific immunity, and detection of secreted quorum sensing peptides. The assay is performed by pre-inoculating an agar plate with a strain to be tested for bacteriocin production followed by application of a soft agar overlay containing a strain to be tested for bacteriocin sensitivity. A zone of clearance surrounding the stab indicates that the overlay strain is sensitive to the bacteriocins produced by the pre-inoculated strain. If no zone of clearance is observed, either the overlay strain is immune to the bacteriocins being produced or the pre-inoculated strain does not produce bacteriocins. To determine if the blp locus is functional in a given strain, the overlay assay can be adapted to evaluate for peptide pheromone secretion by the pre-inoculated strain. In this case, a series of four lacZ-reporter strains with different pheromone specificity are used in the overlay.

  11. Simultaneous overlay and CD measurement for double patterning: scatterometry and RCWA approach

    Science.gov (United States)

    Li, Jie; Liu, Zhuan; Rabello, Silvio; Dasari, Prasad; Kritsun, Oleg; Volkman, Catherine; Park, Jungchul; Singh, Lovejeet

    2009-03-01

    As optical lithography advances to 32 nm technology node and beyond, double patterning technology (DPT) has emerged as an attractive solution to circumvent the fundamental optical limitations. DPT poses unique demands on critical dimension (CD) uniformity and overlay control, making the tolerance decrease much faster than the rate at which critical dimension shrinks. This, in turn, makes metrology even more challenging. In the past, multi-pad diffractionbased overlay (DBO) using empirical approach has been shown to be an effective approach to measure overlay error associated with double patterning [1]. In this method, registration errors for double patterning were extracted from specially designed diffraction targets (three or four pads for each direction); CD variation is assumed negligible within each group of adjacent pads and not addressed in the measurement. In another paper, encouraging results were reported with a first attempt at simultaneously extracting overlay and CD parameters using scatterometry [2]. In this work, we apply scatterometry with a rigorous coupled wave analysis (RCWA) approach to characterize two double-patterning processes: litho-etch-litho-etch (LELE) and litho-freeze-litho-etch (LFLE). The advantage of performing rigorous modeling is to reduce the number of pads within each measurement target, thus reducing space requirement and improving throughput, and simultaneously extract CD and overlay information. This method measures overlay errors and CDs by fitting the optical signals with spectra calculated from a model of the targets. Good correlation is obtained between the results from this method and that of several reference techniques, including empirical multi-pad DBO, CD-SEM, and IBO. We also perform total measurement uncertainty (TMU) analysis to evaluate the overall performance. We demonstrate that scatterometry provides a promising solution to meet the challenging overlay metrology requirement in DPT.

  12. Faster diffraction-based overlay measurements with smaller targets using 3D gratings

    Science.gov (United States)

    Li, Jie; Kritsun, Oleg; Liu, Yongdong; Dasari, Prasad; Volkman, Catherine; Hu, Jiangtao

    2012-03-01

    Diffraction-based overlay (DBO) technologies have been developed to address the overlay metrology challenges for 22nm technology node and beyond. Most DBO technologies require specially designed targets that consist of multiple measurement pads, which consume too much space and increase measurement time. The traditional empirical approach (eDBO) using normal incidence spectroscopic reflectometry (NISR) relies on linear response of the reflectance with respect to overlay displacement within a small range. It offers convenience of quick recipe setup since there is no need to establish a model. However it requires three or four pads per direction (x or y) which adds burden to throughput and target size. Recent advances in modeling capability and computation power enabled mDBO, which allows overlay measurement with reduced number of pads, thus reducing measurement time and DBO target space. In this paper we evaluate the performance of single pad mDBO measurements using two 3D targets that have different grating shapes: squares in boxes and L-shapes in boxes. Good overlay sensitivities are observed for both targets. The correlation to programmed shifts and image-based overlay (IBO) is excellent. Despite the difference in shapes, the mDBO results are comparable for square and L-shape targets. The impact of process variations on overlay measurements is studied using a focus and exposure matrix (FEM) wafer. Although the FEM wafer has larger process variations, the correlation of mDBO results with IBO measurements is as good as the normal process wafer. We demonstrate the feasibility of single pad DBO measurements with faster throughput and smaller target size, which is particularly important in high volume manufacturing environment.

  13. Let’s Get Concrete!

    DEFF Research Database (Denmark)

    Jones, Candace; Boxenbaum, Eva

    whereas in the United States market and professional logics interacted: manufacturers cooperated to create standards for concrete and appealed to architects as consumers. Our findings also illuminate that concrete was legitimated initially by imitation of stone, but this strategy soon de......-legitimated not only concrete but also stone. Concrete was perceived as merely imitative and thus inauthentic. For concrete to become a legitimate and widely adopted material, architects had to theorize concrete as unique material with distinctive aesthetic possibilities, which led to new kinds of buildings and new...... architectural styles. Our study illuminates the key role that materials and aesthetics played within architects’ professional logic and shaped processes of institutional change....

  14. Effect of Fe content on the friction and abrasion properties of copper base overlay on steel substrate by TIG welding

    Institute of Scientific and Technical Information of China (English)

    Lü Shixiong; Song Jianling; Liu Lei; Yang Shiqin

    2009-01-01

    Copper base alloy was overlaid onto 35CrMnSiA steel plate by tungsten inert gas (TIG) welding method. The heat transfer process was simulated, the microstructures of the copper base overlay were analyzed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), and the friction and abrasion properties of the overlay were measured. The results show that the Fe content increases in the overlay with increasing the welding current. And with the increase of Fe content in the overlay, the friction coefficient increases and the wear mechanism changes from oxidation wear to abrasive wear and plough wear, which is related to the size and quantity of Fe grains in the overlay. While with the increase of Fe content in the overlay, the protection of oxidation layer against the oxidation wear on the melted metal decreases.

  15. Studies of historic concrete

    International Nuclear Information System (INIS)

    Jull, S.P.; Lees, T.P.

    1990-01-01

    Underground concrete repositories for nuclear waste will have to maintain their integrity for hundreds of years. This study examines ancient concretes and assesses the suitability of equivalent modern materials for underground storage. Thirty four ancient samples have been obtained from Great Britain, Austria and Italy. One 19th century sample was also collected. The samples were examined using a variety of analytical techniques (including scanning electron microscopy, optical microscopy, chemical analysis and pH determination). The samples were also subjected to a range of physical tests. Most of the samples examined were very weak and porous although they had retained full structural integrity. With the exception of the 19th century sample, none of the concretes had maintained pH alkaline enough to immobilize radionuclides. Hydrated calcium silicates have been detected in some samples which are similar to those observed in modern Portland cement concretes. These stable cementitious species have endured for almost two thousand years. All the ancient concretes and mortars examined contained natural pozzolanic material or crushed burnt clay. This may have had some effect on the reduction in alkalinity although the main reason was full carbonation of calcium hydroxide

  16. Concrete and prestressing process, container made with this concrete

    International Nuclear Information System (INIS)

    Gerard, M.

    1992-01-01

    Shape memory alloy fibers or heat shrinking fibers are encapsulated in a standard concrete. Prestressed concrete is obtained by heat treatment. Application is made to the fabrication of radioactive waste containers

  17. Concrete with onyx waste aggregate as aesthetically valued structural concrete

    Science.gov (United States)

    Setyowati E., W.; Soehardjono, A.; Wisnumurti

    2017-09-01

    The utillization of Tulungagung onyx stone waste as an aggregate of concrete mixture will improve the economic value of the concrete due to the brighter color and high aesthetic level of the products. We conducted the research of 75 samples as a test objects to measure the compression stress, splits tensile stress, flexural tensile stress, elasticity modulus, porosity modulus and also studied 15 test objects to identify the concrete micro structures using XRD test, EDAX test and SEM test. The test objects were made from mix designed concrete, having ratio cement : fine aggregate : coarse aggregate ratio = 1 : 1.5 : 2.1, and W/C ratio = 0.4. The 28 days examination results showed that the micro structure of Tulungagung onyx waste concrete is similar with normal concrete. Moreover, the mechanical test results proved that Tulungagung onyx waste concretes also have a qualified level of strength to be used as a structural concrete with higher aesthetic level.

  18. Durability of lightweight concrete : Phase I : concrete temperature study.

    Science.gov (United States)

    1968-08-01

    This report describes a study conducted to determine the temperature gradient throughout the depth of a six inch concrete bridge deck. The bridge deck selected for study was constructed using lightweight concrete for the center spans and sand and gra...

  19. Effect of constraint condition and internal medium on residual stress under overlay welding for dissimilar metal welding

    International Nuclear Information System (INIS)

    Song, Tae Kwang; Kim, Yun Jae; Lee, Kyoung Soo; Park, Chi Yong; Kim, Jong Sung; Kim, Jin Weon

    2007-01-01

    In nuclear power plants, residual stress of dissimilar metal weld propagates cracks in the weld metal which is susceptible to stress corrosion cracking. Overlay welding is a process widely used to mitigate residual stress replacing inside tensile stress by compression stress. However, according to the result of this study the effect of overlay welding on residual stress depends on both internal medium and constraint condition. The purpose of this study is to maximize the positive effect of overlay welding by finite element analyses

  20. Water Entrainment in Concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben

    This report gives a survey of different techniques for incorporation of designed, water-filled cavities in concrete: Water entrainment. Also an estimate of the optimum size of the water inclusions is given. Water entrainment can be used to avoid self-desiccation and self-desiccation shrinkage...... during hydration [1,26]. What is needed is some sort of container which retains the shape of the water when mixed into the concrete. The container may function based on several different physical or chemical principles. Cells and gels are examples of containers found in nature. A cell membrane provides...... a boundary to water, whereas a polymer network incorporates water in its intersticious space with its affinity due to interaction energy and polymer entropy. Such containers allow water to be stored as an entity. In relation to concrete the water encapsulation may be accomplished either before or after start...

  1. Drying of Concrete

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Geiker, Mette Rica; Nygaard, Peter Vagn

    2002-01-01

    Estimated and measured relative humidity (RH) change during drying are compared for two concretes, 1: w/c=0.46 and 2: w/(c+0.5fa+2sf)=0.50. The estimations were undertaken by means of the Swedish program TorkaS 1.0. Measurements were performed by RH-sensors type Humi-Guard. Drying of 150 mm thick...... samples from sides at 60% RH and 22 °C took place from 4 to 56 days after casting. At the end of the drying period the measured RH was about 4% lower than the estimated RH at 1/5th depth from the exposed surface for both concretes. In the middle of the samples, the measured RH of concretes 1 and 2 were 2...

  2. Colonization of overlaying water by bacteria from dry river sediments.

    Science.gov (United States)

    Fazi, Stefano; Amalfitano, Stefano; Piccini, Claudia; Zoppini, Annamaria; Puddu, Alberto; Pernthaler, Jakob

    2008-10-01

    We studied the diversity, community composition and activity of the primary microbial colonizers of the water above freshly re-wetted sediments from a temporary river. Dried sediments, collected from Mulargia River (Sardinia, Italy), were covered with sterile freshwater in triplicate microcosms, and changes of the planktonic microbial assemblage were monitored over a 48 h period. During the first 9 h bacterial abundance was low (1.5 x 10(4) cells ml(-1)); it increased to 3.4 x 10(6) cells ml(-1) after 28 h and did not change thereafter. Approximately 20% of bacteria exhibited DNA de novo synthesis already after 9 h of incubation. Changes of the ratios of (3)H-leucine to (3)H-thymidine incorporation rates indicated a shift of growth patterns during the experiment. Extracellular enzyme activity showed a maximum at 48 h with aminopeptidase activity (430.8 +/- 22.6 nmol MCA l(-1) h(-1)) significantly higher than alkaline phosphatase (98.6 +/- 4.3 nmol MUF l(-1) h(-1)). The primary microbial colonizers of the overlaying water - as determined by 16S rRNA gene sequence analysis - were related to at least six different phylogenetic lineages of Bacilli and to Alphaproteobacteria (Brevundimonas spp. and Caulobacter spp.). Large bacterial cells affiliated to one clade of Bacillus sp. were rare in the dried sediments, but constituted the majority of the planktonic microbial assemblage and of cells with detectable DNA-synthesis until 28 h after re-wetting. Their community contribution decreased in parallel with a rise of flagellated and ciliated protists. Estimates based on cell production rates suggested that the rapidly enriched Bacillus sp. suffered disproportionally high loss rates from selective predation, thus favouring the establishment of a more heterogenic assemblage of microbes (consisting of Proteobacteria, Actinobacteria and Cytophaga-Flavobacteria). Our results suggest that the primary microbial colonizers of the water above dried sediments are passively released

  3. Use of fiber reinforced concrete for concrete pavement slab replacement.

    Science.gov (United States)

    2014-03-01

    Unlike ordinary concrete pavement, replacement concrete slabs need to be open to traffic within 24 hours (sooner in : some cases). Thus, high early-strength concrete is used; however, it frequently cracks prematurely as a result of high : heat of hyd...

  4. Overlay control methodology comparison: field-by-field and high-order methods

    Science.gov (United States)

    Huang, Chun-Yen; Chiu, Chui-Fu; Wu, Wen-Bin; Shih, Chiang-Lin; Huang, Chin-Chou Kevin; Huang, Healthy; Choi, DongSub; Pierson, Bill; Robinson, John C.

    2012-03-01

    Overlay control in advanced integrated circuit (IC) manufacturing is becoming one of the leading lithographic challenges in the 3x and 2x nm process nodes. Production overlay control can no longer meet the stringent emerging requirements based on linear composite wafer and field models with sampling of 10 to 20 fields and 4 to 5 sites per field, which was the industry standard for many years. Methods that have emerged include overlay metrology in many or all fields, including the high order field model method called high order control (HOC), and field by field control (FxFc) methods also called correction per exposure. The HOC and FxFc methods were initially introduced as relatively infrequent scanner qualification activities meant to supplement linear production schemes. More recently, however, it is clear that production control is also requiring intense sampling, similar high order and FxFc methods. The added control benefits of high order and FxFc overlay methods need to be balanced with the increased metrology requirements, however, without putting material at risk. Of critical importance is the proper control of edge fields, which requires intensive sampling in order to minimize signatures. In this study we compare various methods of overlay control including the performance levels that can be achieved.

  5. A Persistent Structured Hierarchical Overlay Network to Counter Intentional Churn Attack

    Directory of Open Access Journals (Sweden)

    Ramanpreet Kaur

    2016-01-01

    Full Text Available The increased use of structured overlay network for a variety of applications has attracted a lot of attention from both research community and attackers. However, the structural constraints, open nature (anybody can join and anybody may leave, and unreliability of its participant nodes significantly affect the performance of these applications and make it vulnerable to a variety of attacks such as eclipse, Sybil, and churn. One attack to compromise the service availability in overlay network is intentional churn (join/leave attack, where a large number of malicious users will join and leave the overlay network so frequently that the entire structure collapses and becomes unavailable. The focus of this paper is to provide a new robust, efficient, and scalable hierarchical overlay architecture that will counter these attacks by providing a structure that can accommodate the fleeting behaviour of nodes without causing much structural inconsistencies. The performance evaluation showed that the proposed architecture has more failure resilience and self-organization as compared to chord based architecture. Experimental results have demonstrated that the effect of failures on an overlay is proportional to the size of failure.

  6. A Measurement Study of the Structured Overlay Network in P2P File-Sharing Systems

    Directory of Open Access Journals (Sweden)

    Mo Zhou

    2007-01-01

    Full Text Available The architecture of P2P file-sharing applications has been developing to meet the needs of large scale demands. The structured overlay network, also known as DHT, has been used in these applications to improve the scalability, and robustness of the system, and to make it free from single-point failure. We believe that the measurement study of the overlay network used in the real file-sharing P2P systems can provide guidance for the designing of such systems, and improve the performance of the system. In this paper, we perform the measurement in two different aspects. First, a modified client is designed to provide view to the overlay network from a single-user vision. Second, the instances of crawler programs deployed in many nodes managed to crawl the user information of the overlay network as much as possible. We also find a vulnerability in the overlay network, combined with the character of the DNS service, a more serious DDoS attack can be launched.

  7. Effects of Spectral Overlays on Reading Performance of Brazilian Elementary School Children.

    Science.gov (United States)

    Garcia, Ana Carla Oliveira; Momensohn-Santos, Teresa Maria; Vilhena, Douglas de Araújo

    2018-03-20

    To investigate the effects of spectral overlays on reading performance of Brazilian elementary school children. Sixty-eight children (aged 9-12 years) enrolled in the 5th and 6th grade were included in the study. The Rate of Reading Test (RRT - Brazilian Portuguese version) was used to evaluate reading speed and the Irlen Reading Perceptual Scale was used to allocate the sample according to reading difficulty/discomfort symptoms and to define the optimal spectral overlays. A total of 13% of the children presented an improvement of at least 15% in reading speed with the use of spectral overlays. Pupils with severe reading difficulties tended to have more improvement in RRT with spectral overlays. Children with severe reading discomfort obtained the highest gains in RRT, with an average of 9.6% improvement with intervention, compared to a decrease of -8.2% in the control group. Participants with severe discomfort had an odds ratio of 3.36 to improve reading speed with intervention compared to the control group. The use of spectral overlays can improve reading performance, particularly in those children with severe visual discomfort. © 2018 S. Karger AG, Basel.

  8. Implementation and benefits of advanced process control for lithography CD and overlay

    Science.gov (United States)

    Zavyalova, Lena; Fu, Chong-Cheng; Seligman, Gary S.; Tapp, Perry A.; Pol, Victor

    2003-05-01

    Due to the rapidly reduced imaging process windows and increasingly stingent device overlay requirements, sub-130 nm lithography processes are more severely impacted than ever by systamic fault. Limits on critical dimensions (CD) and overlay capability further challenge the operational effectiveness of a mix-and-match environment using multiple lithography tools, as such mode additionally consumes the available error budgets. Therefore, a focus on advanced process control (APC) methodologies is key to gaining control in the lithographic modules for critical device levels, which in turn translates to accelerated yield learning, achieving time-to-market lead, and ultimately a higher return on investment. This paper describes the implementation and unique challenges of a closed-loop CD and overlay control solution in high voume manufacturing of leading edge devices. A particular emphasis has been placed on developing a flexible APC application capable of managing a wide range of control aspects such as process and tool drifts, single and multiple lot excursions, referential overlay control, 'special lot' handling, advanced model hierarchy, and automatic model seeding. Specific integration cases, including the multiple-reticle complementary phase shift lithography process, are discussed. A continuous improvement in the overlay and CD Cpk performance as well as the rework rate has been observed through the implementation of this system, and the results are studied.

  9. Characterisation of hydrocarbonaceous overlayers important in metal-catalysed selective hydrogenation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Lennon, David; Warringham, Robbie [School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Guidi, Tatiana [ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Parker, Stewart F., E-mail: stewart.parker@stfc.ac.uk [ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)

    2013-12-12

    Highlights: • Inelastic neutron scattering spectroscopy of a commercial dehydrogenation catalyst. • The overlayer present on the catalyst is predominantly aliphatic. • A population of strongly hydrogen bonded hydroxyls is also present. - Abstract: The hydrogenation of alkynes to alkenes over supported metal catalysts is an important industrial process and it has been shown that hydrocarbonaceous overlayers are important in controlling selectivity profiles of metal-catalysed hydrogenation reactions. As a model system, we have selected propyne hydrogenation over a commercial Pd(5%)/Al{sub 2}O{sub 3} catalyst. Inelastic neutron scattering studies show that the C–H stretching mode ranges from 2850 to 3063 cm{sup −1}, indicating the mostly aliphatic nature of the overlayer and this is supported by the quantification of the carbon and hydrogen on the surface. There is also a population of strongly hydrogen-bonded hydroxyls, their presence would indicate that the overlayer probably contains some oxygen functionality. There is little evidence for any olefinic or aromatic species. This is distinctly different from the hydrogen-poor overlayers that are deposited on Ni/Al{sub 2}O{sub 3} catalysts during methane reforming.

  10. Reduction of image-based ADI-to-AEI overlay inconsistency with improved algorithm

    Science.gov (United States)

    Chen, Yen-Liang; Lin, Shu-Hong; Chen, Kai-Hsiung; Ke, Chih-Ming; Gau, Tsai-Sheng

    2013-04-01

    In image-based overlay (IBO) measurement, the measurement quality of various measurement spectra can be judged by quality indicators and also the ADI-to-AEI similarity to determine the optimum light spectrum. However we found some IBO measured results showing erroneous indication of wafer expansion from the difference between the ADI and the AEI maps, even after their measurement spectra were optimized. To reduce this inconsistency, an improved image calculation algorithm is proposed in this paper. Different gray levels composed of inner- and outer-box contours are extracted to calculate their ADI overlay errors. The symmetry of intensity distribution at the thresholds dictated by a range of gray levels is used to determine the particular gray level that can minimize the ADI-to-AEI overlay inconsistency. After this improvement, the ADI is more similar to AEI with less expansion difference. The same wafer was also checked by the diffraction-based overlay (DBO) tool to verify that there is no physical wafer expansion. When there is actual wafer expansion induced by large internal stress, both the IBO and the DBO measurements indicate similar expansion results. The scanning white-light interference microscope was used to check the variation of wafer warpage during the ADI and AEI stages. It predicts a similar trend with the overlay difference map, confirming the internal stress.

  11. Diffraction-based overlay measurement on dedicated mark using rigorous modeling method

    Science.gov (United States)

    Lu, Hailiang; Wang, Fan; Zhang, Qingyun; Chen, Yonghui; Zhou, Chang

    2012-03-01

    Diffraction Based Overlay (DBO) is widely evaluated by numerous authors, results show DBO can provide better performance than Imaging Based Overlay (IBO). However, DBO has its own problems. As well known, Modeling based DBO (mDBO) faces challenges of low measurement sensitivity and crosstalk between various structure parameters, which may result in poor accuracy and precision. Meanwhile, main obstacle encountered by empirical DBO (eDBO) is that a few pads must be employed to gain sufficient information on overlay-induced diffraction signature variations, which consumes more wafer space and costs more measuring time. Also, eDBO may suffer from mark profile asymmetry caused by processes. In this paper, we propose an alternative DBO technology that employs a dedicated overlay mark and takes a rigorous modeling approach. This technology needs only two or three pads for each direction, which is economic and time saving. While overlay measurement error induced by mark profile asymmetry being reduced, this technology is expected to be as accurate and precise as scatterometry technologies.

  12. Concentrated loads on concrete

    DEFF Research Database (Denmark)

    Lorenzen, Karen Grøndahl; Nielsen, Mogens Peter

    1997-01-01

    This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas are devel......This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas...

  13. Sprayed concrete linings

    Energy Technology Data Exchange (ETDEWEB)

    Hindle, D.

    1999-12-01

    Sprayed concrete, or shotcrete, was invented in the 1920s for preserving dinosaur skeletons and was used underground initially in coalmines for the preservation and fine proofing of timber supports. Its use as a support lining in rock tunnelling was developed in the 1950s and 60s. The article surveys equipment available from major manufacturers and suppliers of concrete spraying equipment (Aliva, Cifa, GIA, Industri, Ingersoll Rand, etc.), specialist cement and additive manufacturers (Castle, Cement, Moria Carbotech). manufacturers of lattice girders and fibre reinforcement, and manufacturers of instrumentation for tunnel linings. 5 tabs., 9 photos.

  14. Electrokinetic decontamination of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Lomasney, H. [ISOTRON Corp., New Orleans, LA (United States)

    1995-10-01

    The U.S. Department of Energy has assigned a priority to the advancement of technology for decontaminating concrete surfaces which have become contaminated with radionuclides, heavy metals, and toxic organics. This agency is responsible for decontamination and decommissioning of thousands of buildings. Electrokinetic extraction is one of the several innovative technologies which emerged in response to this initiative. This technique utilizes an electropotential gradient and the subsequent electrical transport mechanism to cause the controlled movement of ionics species, whereby the contaminants exit the recesses deep within the concrete. This report discusses the technology and use at the Oak Ridge k-25 plant.

  15. Structural Materials: 95. Concrete

    International Nuclear Information System (INIS)

    Naus, Dan J.

    2012-01-01

    Nuclear power plant concrete structures and their materials of construction are described, and their operating experience noted. Aging and environmental factors that can affect the durability of the concrete structures are identified. Basic components of a program to manage aging of these structures are identified and described. Application of structural reliability theory to devise uniform risk-based criteria by which existing facilities can be evaluated to achieve a desired performance level when subjected to uncertain demands and to quantify the effects of degradation is outlined. Finally, several areas are identified where additional research is desired.

  16. Improved concretes for corrosion resistance

    Science.gov (United States)

    1997-07-01

    The deterioration of various reinforced concrete bridge components containing conventional black steel reinforcement is the most important problem facing U.S. highway agencies. A major cause of this concrete deterioration (cracking, delamination, and...

  17. Modeling reinforced concrete durability : [summary].

    Science.gov (United States)

    2014-06-01

    Many Florida bridges are built of steel-reinforced concrete. Floridas humid and marine : environments subject steel in these structures : to corrosion once water and salt penetrate the : concrete and contact the steel. Corroded steel : takes up mo...

  18. Advance Organizers: Concret Versus Abstract.

    Science.gov (United States)

    Corkill, Alice J.; And Others

    1988-01-01

    Two experiments examined the relative effects of concrete and abstract advance organizers on students' memory for subsequent prose. Results of the experiments are discussed in terms of the memorability, familiarity, and visualizability of concrete and abstract verbal materials. (JD)

  19. Applications of Foamed Lightweight Concrete

    Directory of Open Access Journals (Sweden)

    Mohd Sari Kamarul Aini

    2017-01-01

    Full Text Available Application of foamed concrete is increasing at present due to high demand on foamed concrete structures with good mechanical and physical properties. This paper discusses on the use of basic raw materials, their characteristics, production process, and their application in foamed lightweight concrete with densities between 300 kg/m3 and 1800 kg/m3. It also discusses the factors that influence the strengths and weaknesses of foamed concrete based on studies that were conducted previously.

  20. TEXTILE TECHNOLOGIES IN CONCRETE ENVIRONMENTS."

    OpenAIRE

    Morrow, Ruth; Belford, Patricia

    2007-01-01

    Girli Concrete is a cross disciplinary funded research project based in the University of Ulster involving a textile designer/ researcher, an architect/ academic and a concrete manufacturing firm.Girli Concrete brings together concrete and textile technologies, testing ideas ofconcrete as textile and textile as structure. It challenges the perception of textiles as only the ‘dressing’ to structure and instead integrates textile technologies into the products of building products. Girli Concre...

  1. Constitutive model for reinforced concrete

    NARCIS (Netherlands)

    Feenstra, P.H.; Borst, de R.

    1995-01-01

    A numerical model is proposed for reinforced-concrete behavior that combines the commonly accepted ideas from modeling plain concrete, reinforcement, and interaction behavior in a consistent manner. The behavior of plain concrete is govern by fracture-energy-level-based formulation both in tension

  2. Porous Concrete and Its Application

    Directory of Open Access Journals (Sweden)

    V. V. Opekunov

    2005-01-01

    Full Text Available Some aspects of resource saving problem in the process of mass construction and operation of heated construction installations are considered in the paper. A special attention is paid to necessary application of porous concrete products in the process of the housing construction. The preference is given to the products made of autoclave cellular concrete and cement hydrophobisized cement perlite concrete.

  3. Concrete produced with recycled aggregates

    Directory of Open Access Journals (Sweden)

    J. J. L. Tenório

    Full Text Available This paper presents the analysis of the mechanical and durable properties of recycled aggregate concrete (RAC for using in concrete. The porosity of recycled coarse aggregates is known to influence the fresh and hardened concrete properties and these properties are related to the specific mass of the recycled coarse aggregates, which directly influences the mechanical properties of the concrete. The recycled aggregates were obtained from construction and demolition wastes (CDW, which were divided into recycled sand (fine and coarse aggregates. Besides this, a recycled coarse aggregate of a specific mass with a greater density was obtained by mixing the recycled aggregates of the CDW with the recycled aggregates of concrete wastes (CW. The concrete was produced in laboratory by combining three water-cement ratios, the ratios were used in agreement with NBR 6118 for structural concretes, with each recycled coarse aggregates and recycled sand or river sand, and the reference concrete was produced with natural aggregates. It was observed that recycled aggregates can be used in concrete with properties for structural concrete. In general, the use of recycled coarse aggregate in combination with recycled sand did not provide good results; but when the less porous was used, or the recycled coarse aggregate of a specific mass with a greater density, the properties of the concrete showed better results. Some RAC reached bigger strengths than the reference concrete.

  4. Structural Concrete, Science into Practice

    NARCIS (Netherlands)

    Bruggeling, A.S.G.

    1987-01-01

    There is a need for a more rational and unified approach to all types of concrete structure, reinforced of prestressed. The first chapter explains in a historical review why the approach of reinforced concrete and that of prestressed concrete have hitherto been very different. In outlining the

  5. Characterizing the Global Impact of P2P Overlays on the AS-Level Underlay

    Science.gov (United States)

    Rasti, Amir Hassan; Rejaie, Reza; Willinger, Walter

    This paper examines the problem of characterizing and assessing the global impact of the load imposed by a Peer-to-Peer (P2P) overlay on the AS-level underlay. In particular, we capture Gnutella snapshots for four consecutive years, obtain the corresponding AS-level topology snapshots of the Internet and infer the AS-paths associated with each overlay connection. Assuming a simple model of overlay traffic, we analyze the observed load imposed by these Gnutella snapshots on the AS-level underlay using metrics that characterize the load seen on individual AS-paths and by the transit ASes, illustrate the churn among the top transit ASes during this 4-year period, and describe the propagation of traffic within the AS-level hierarchy.

  6. Dynamics of a metal overlayer on metallic substrates: High temperature effects

    International Nuclear Information System (INIS)

    Rahman, T.S.; Black, J.E.; Tian, Zeng Ju

    1992-01-01

    We have explored the structure and the dynamics of a bimetallic system consisting of a hexagonal (almost) overlayer of Ag on a square lattice (Ni(100) and Cu(100)), as a function of the surface temperature. In each case the structure is ''nearly'' incommensurate giving rise to a low frequency Goldstone mode. Also, the overlayer atoms slosh back and forth over the substrate in a corrugated fashion. The calculated dispersion of the Ag/metal vertical mode, at room temperature, is in excellent agreement with experimental data. At higher temperatures floater atoms appear on top of the overlayer displaying a variety of cluster formations and also exchanges with the substrate atoms leading to surface disordering, interdiffusion and melting

  7. Evaluation of a novel ultra small target technology supporting on-product overlay measurements

    Science.gov (United States)

    Smilde, Henk-Jan H.; den Boef, Arie; Kubis, Michael; Jak, Martin; van Schijndel, Mark; Fuchs, Andreas; van der Schaar, Maurits; Meyer, Steffen; Morgan, Stephen; Wu, Jon; Tsai, Vincent; Wang, Cathy; Bhattacharyya, Kaustuve; Chen, Kai-Hsiung; Huang, Guo-Tsai; Ke, Chih-Ming; Huang, Jacky

    2012-03-01

    Reducing the size of metrology targets is essential for in-die overlay metrology in advanced semiconductor manufacturing. In this paper, μ-diffraction-based overlay (μDBO) measurements with a YieldStar metrology tool are presented for target-sizes down to 10 × 10 μm2. The μDBO technology enables selection of only the diffraction efficiency information from the grating by efficiently separating it from product structure reflections. Therefore, μDBO targets -even when located adjacent to product environment- give excellent correlation with 40 × 160 μm2 reference targets. Although significantly smaller than standard scribe-line targets, they can achieve total-measurement-uncertainty values of below 0.5 nm on a wide range of product layers. This shows that the new μDBO technique allows for accurate metrology on ultra small in-die targets, while retaining the excellent TMU performance of diffraction-based overlay metrology.

  8. On the influence of latency estimation on dynamic group communication using overlays

    Science.gov (United States)

    Vik, Knut-Helge; Griwodz, Carsten; Halvorsen, Pål

    2009-01-01

    Distributed interactive applications tend to have stringent latency requirements and some may have high bandwidth demands. Many of them have also very dynamic user groups for which all-to-all communication is needed. In online multiplayer games, for example, such groups are determined through region-of-interest management in the application. We have investigated a variety of group management approaches for overlay networks in earlier work and shown that several useful tree heuristics exist. However, these heuristics require full knowledge of all overlay link latencies. Since this is not scalable, we investigate the effects that latency estimation techqniues have ton the quality of overlay tree constructions. We do this by evaluating one example of our group management approaches in Planetlab and examing how latency estimation techqniues influence their quality. Specifically, we investigate how two well-known latency estimation techniques, Vivaldi and Netvigator, affect the quality of tree building.

  9. Welding overlay analysis of dissimilar metal weld cracking of feedwater nozzle

    International Nuclear Information System (INIS)

    Tsai, Y.L.; Wang, Li. H.; Fan, T.W.; Ranganath, Sam; Wang, C.K.; Chou, C.P.

    2010-01-01

    Inspection of the weld between the feedwater nozzle and the safe end at one Taiwan BWR showed axial indications in the Alloy 182 weld. The indication was sufficiently deep that continued operation could not be justified considering the crack growth for one cycle. A weld overlay was decided to implement for restoring the structural margin. This study reviews the cracking cases of feedwater nozzle welds in other nuclear plants, and reports the lesson learned in the engineering project of this weld overlay repair. The overlay design, the FCG calculation and the stress analysis by FEM are presented to confirm that the Code Case structural margins are met. The evaluations of the effect of weld shrinkage on the attached feedwater piping are also included. A number of challenges encountered in the engineering and analysis period are proposed for future study.

  10. A study of swing-curve physics in diffraction-based overlay

    Science.gov (United States)

    Bhattacharyya, Kaustuve; den Boef, Arie; Storms, Greet; van Heijst, Joost; Noot, Marc; An, Kevin; Park, Noh-Kyoung; Jeon, Se-Ra; Oh, Nang-Lyeom; McNamara, Elliott; van de Mast, Frank; Oh, SeungHwa; Lee, Seung Yoon; Hwang, Chan; Lee, Kuntack

    2016-03-01

    With the increase of process complexity in advanced nodes, the requirements of process robustness in overlay metrology continues to tighten. Especially with the introduction of newer materials in the film-stack along with typical stack variations (thickness, optical properties, profile asymmetry etc.), the signal formation physics in diffraction-based overlay (DBO) becomes an important aspect to apply in overlay metrology target and recipe selection. In order to address the signal formation physics, an effort is made towards studying the swing-curve phenomena through wavelength and polarizations on production stacks using simulations as well as experimental technique using DBO. The results provide a wealth of information on target and recipe selection for robustness. Details from simulation and measurements will be reported in this technical publication.

  11. Forterra Concrete Products, Inc.

    Science.gov (United States)

    The EPA is providing notice of a proposed Administrative Penalty Assessment against Forterra Concrete Products, Inc., a business located at 511 E. John Carpenter Freeway, Irving, TX, 75062, for alleged violations at its facility located at 23600 W. 40th St

  12. Teaching concrete structures

    DEFF Research Database (Denmark)

    Goltermann, Per

    2014-01-01

    The teaching of concrete structures has been revised and a number of new approaches have been developed, implemented and evaluated. Inductive teaching, E-learning and “patches” have been found to be improvements and may be an inspiration and help for others development of the teaching and learning...

  13. Anisotropic Concrete Compressive Strength

    DEFF Research Database (Denmark)

    Gustenhoff Hansen, Søren; Jørgensen, Henrik Brøner; Hoang, Linh Cao

    2017-01-01

    When the load carrying capacity of existing concrete structures is (re-)assessed it is often based on compressive strength of cores drilled out from the structure. Existing studies show that the core compressive strength is anisotropic; i.e. it depends on whether the cores are drilled parallel...

  14. Continuous Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1996-01-01

    This report deals with stress and stiffness estimates of continuous reinforced concrete beams with different stiffnesses for negative and positive moments e.g. corresponding to different reinforcement areas in top and bottom. Such conditions are often met in practice.The moment distribution...

  15. Hydrophobic treatment of concrete

    NARCIS (Netherlands)

    Vries, J. de; Polder, R.B.

    1996-01-01

    As part of the maintenance policy of the Dutch Ministry of Transport, Civil Engineering Division, hydrophobic treatment of concrete was considered as an additional protective measure against penetration of aggressive substances, for instance deicing salts in bridge decks. A set of tests was designed

  16. Concrete longevity overview

    International Nuclear Information System (INIS)

    Chang, W.; Morreale, B.

    1991-01-01

    A number of compact host states and unaffiliated states are currently selecting appropriate disposal technology and construction materials for their planned low-level radioactive waste (LLW) disposal facilities. Concrete is one of the candidate materials under consideration for the construction of LLW disposal facilities because of its strength, durability, abundant availability, and relatively low cost. The LLW disposal facilities must maintain intruder barrier integrity for up to 500 years, without active maintenance after the first 100 years. The ability of concrete to survive for such a long time as a construction material is a critical issue. This report provides a basic understanding of the composition and workings of concrete as a structural material in LLW disposal facilities and a description of degradation factors and state-of-the-art mitigative measures available to preserve the durability and longevity of concrete. Neither the paper nor the report is intended to be a design guidance document, and neither addresses using cement as a waste solidification agent. 5 refs., 1 tab

  17. Fracture Mechanics of Concrete

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    the international workshop on concrete fracture, organised by A Carpinteri, at Torino ... The next question is how to bring the size effect into codes of practice on the ... analysis of the recent collapse of the World Trade Center in New York by Z P ...

  18. Contaminated soil concrete blocks

    NARCIS (Netherlands)

    de Korte, A.C.J.; Brouwers, Jos; Limbachiya, Mukesh C.; Kew, Hsein Y.

    2009-01-01

    According to Dutch law the contaminated soil needs to be remediated or immobilised. The main focus in this article is the design of concrete blocks, containing contaminated soil, that are suitable for large production, financial feasible and meets all technical and environmental requirements. In

  19. Electrical pulses protect concrete

    NARCIS (Netherlands)

    Koleva, D.; Fraaij, A.; Van Kasteren, J.

    2006-01-01

    Even concrete is not as hard as it looks. Sea water, salt on icy roads, and indirectly even carbon dioxide from the air can corrode the steel of the reinforcing bars and so threaten the strength and integrity of a bridge pier, jetty, or viaduct. Dessi Koleva, a chemical engineer from Bulgaria, spent

  20. CONCRETE REACTOR CONTAINMENT

    Energy Technology Data Exchange (ETDEWEB)

    Lumb, Ralph F.; Hall, William F.; Fruchtbaum, Jacob

    1963-06-15

    The results of various leak-rate tests demonstrate the practicality of concrete as primary containment for the maximum credible accident for a research reactor employing plate-type fuel and having a power in excess of one megawatt. Leak-test time was shortened substantially by measuring the relaxation time for overpressure decay, which is a function of leak rate. (auth)

  1. Electroosmotic decontamination of concrete

    International Nuclear Information System (INIS)

    Bostick, W.D.; Bush, S.A.; Marsh, G.C.; Henson, H.M.; Box, W.D.; Morgan, I.L.

    1993-03-01

    A method is described for the electroosmotic decontamination of concrete surfaces, in which an electrical field is used to induce migration of ionic contaminants from porous concrete into an electrolyte solution that may be disposed of as a low-level liquid radioactive waste (LLRW); alternately, the contaminants from the solution can be sorbed onto anion exchange media in order to prevent contaminant buildup in the solution and to minimize the amount of LLRW generated. We have confirmed the removal of uranium (and infer the removal of 99 Tc) from previously contaminated concrete surfaces. In a typical experimental configuration, a stainless steel mesh is placed in an electrolyte solution contained within a diked cell to serve as the negative electrode (cathode) and contaminant collection medium, respectively, and an existing metal penetration (e.g., piping, conduit, or rebar reinforcement within the concrete surface) serves as the positive electrode (anode) to complete the cell. Typically we have achieved 70 to >90% reductions in surface activity by applying 2 )

  2. Concrete. Connecting Creative Technologists

    NARCIS (Netherlands)

    Bakker, T.P.; Huijboom, N.M.; Koops, R.; Kotterink, B.; Nieuwenhuis, O.A.; Seiffert, L.; Siem, R.; Zee, F.A. van der

    2015-01-01

    Kruisbestuiving tussen de creatieve en high-tech sector biedt enorme kansen, bijvoorbeeld op het gebied van Smart Industry. Desondanks blijven deze kansen in de praktijk vaak onderbenut. In het project 'CONCRETE' heeft TNO op basis van een aantal case studies onderzocht welke succesfactoren tot een

  3. Intermittent-contact scanning capacitance microscopy imaging and modeling for overlay metrology

    International Nuclear Information System (INIS)

    Mayo, S.; Kopanski, J. J.; Guthrie, W. F.

    1998-01-01

    Overlay measurements of the relative alignment between sequential layers are one of the most critical issues for integrated circuit (IC) lithography. We have implemented on an AFM platform a new intermittent-contact scanning capacitance microscopy (IC-SCM) mode that is sensitive to the tip proximity to an IC interconnect, thus making it possible to image conductive structures buried under planarized dielectric layers. Such measurements can be used to measure IC metal-to-resist lithography overlay. The AFM conductive cantilever probe oscillating in a vertical plane was driven at frequency ω, below resonance. By measuring the tip-to-sample capacitance, the SCM signal is obtained as the difference in capacitance, ΔC(ω), at the amplitude extremes. Imaging of metallization structures was obtained with a bars-in-bars aluminum structure embedded in a planarized dielectric layer 1 μm thick. We have also modeled, with a two-dimensional (2D) electrostatic field simulator, IC-SCM overlay data of a metallization structure buried under a planarized dielectric having a patterned photoresist layer deposited on it. This structure, which simulates the metal-to-resist overlay between sequential IC levels, allows characterization of the technique sensitivity. The capacitance profile across identical size electrically isolated or grounded metal lines embedded in a dielectric was shown to be different. The floating line shows capacitance enhancement at the line edges, with a minimum at the line center. The grounded line shows a single capacitance maximum located at the line center, with no edge enhancement. For identical line dimensions, the capacitance is significantly larger for grounded lines making them easier to image. A nonlinear regression algorithm was developed to extract line center and overlay parameters with approximately 3 nm resolution at the 95% confidence level, showing the potential of this technique for sub-micrometer critical dimension metrology. Symmetric test

  4. Performance Evaluation of Cognitive Interference Channels Using a Spectrum Overlay Strategy

    Science.gov (United States)

    Knoblock, Eric J.

    2018-01-01

    The use of cognitive radios (CR) and cooperative communications techniques may assist in interference mitigation via sensing of the environment and dynamically altering communications parameters through the use of various mechanisms - one of which is the overlay technique. This report provides a performance analysis of an interference channel with a cognitive transceiver operating in an overlay configuration to evaluate the gains from using cognition. As shown in this report, a cognitive transceiver can simultaneously share spectrum while enhancing performance of non-cognitive nodes via knowledge of the communications channel as well as knowledge of neighboring users' modulation and coding schemes.

  5. Self-compacting concrete (SCC)

    DEFF Research Database (Denmark)

    Geiker, Mette Rica

    2008-01-01

    In many aspects Self-Compacting Concrete (SCC, “Self-Consolidating Concrete” in North America) can be considered the concrete of the future. SCC is a family of tailored concretes with special engineered properties in the fresh state. SCC flows into the formwork and around even complicated...... reinforcement arrangements under its own weight. Thus, SCC is not vibrated like conventional concrete. This drastically improves the working environment during construction, the productivity, and potentially improves the homogeneity and quality of the concrete. In addition SCC provides larger architectural...

  6. Early Property Development in Concrete

    DEFF Research Database (Denmark)

    Normann, Gitte; Munch-Petersen, Christian

    The Freiesleben Maturity function is widely used for planning of execution. We tested if for concrete with and without fly ash. The test showed surprisingly that the maturity function in general is not valid. We found that curing at high temperature gave a significant decrease in strength. Fly ash...... appears to reduce this decrease somewhat. We also examined the resistance against chloride penetration for the different concrete types. The resistance was reduced at high temperatures for concrete without fly ash. For concrete with fly ash, it was the opposite; concrete with fly ash obtained higher...

  7. 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.

  8. An historical examination of concrete

    International Nuclear Information System (INIS)

    Mallinson, L.G.

    1986-03-01

    The requirement that concrete in nuclear waste repositories be stable physically and chemically for hundreds, if not thousands, of years has initiated studies of ancient and old concretes. The history of cement and concrete is described. The oldest know concrete, from Yugoslavia, is ca. 7,500 years old. Concrete was used in many ancient civilisations, including those of Egypt, Greece and Rome. Ancient concretes were usually based upon lime, but sometimes gypsum was used. Pure lime concretes hardened by atomospheric carbonation but the Ancients, in particular the Romans, also employed hydraulic limes and discovered pozzolanas to make superior concretes which, upon hardening, contained complex cementitious hydrates including calcium-silicate-hydrate (CSH), the principal binding element in Portland cement concrete. Portland cement was not invented until 1824 or later and consists principally of calcium silicates formed by clinkerisation of a mixture of limestone and clay in carefully measured proportions. The cement sets hydraulically to form, principally, calcium hydroxide and CSH, the latter being an amorphous or semi-amorphous substance of variable composition. The published literature relating to the analysis of old and ancient cements and concretes is reviewed. A suite of samples spanning the history of concrete has been obtained. A variety of physical and chemical techniques have been employed to characterise these samples. (author)

  9. Life Cycle Assessment of Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Sjunnesson, Jeannette

    2005-09-15

    This is an environmental study on concrete that follows the standard protocol of life cycle assessment (LCA). The study is done for two types of concrete, ordinary and frost-resistant concrete, and has an extra focus on the superplasticizers used as admixtures. The utilization phase is not included in this study since the type of construction for which the concrete is used is not defined and the concrete is assumed to be inert during this phase. The results show that it is the production of the raw material and the transports involved in the life cycle of concrete that are the main contributors to the total environmental load. The one single step in the raw material production that has the highest impact is the production of cement. Within the transportation operations the transportation of concrete is the largest contributor, followed by the transportation of the cement. The environmental impact of frost-resistant concrete is between 24-41 % higher than that of ordinary concrete due to its higher content of cement. Superplasticizers contribute with approximately 0.4-10.4 % of the total environmental impact of concrete, the least to the global warming potential (GWP) and the most to the photochemical ozone creation potential (POCP). Also the toxicity of the superplasticizers is investigated and the conclusion is that the low amount of leakage of superplasticizers from concrete leads to a low risk for the environment and for humans.

  10. Description of the signal and background event mixing as implemented in the Marlin processor OverlayTiming

    CERN Document Server

    Schade, P

    2011-01-01

    This note documents OverlayTiming, a processor in the Marlin software frame- work. OverlayTiming can model the timing structure of a linear collider bunch train and offers the possibility to merge simulated physics events with beam-beam background events. In addition, a realistic structure of the detector readout can be imitated by defining readout time windows for each subdetector.

  11. C-arm Cone Beam Computed Tomographic Needle Path Overlay for Fluoroscopic-Guided Placement of Translumbar Central Venous Catheters

    International Nuclear Information System (INIS)

    Tam, Alda; Mohamed, Ashraf; Pfister, Marcus; Rohm, Esther; Wallace, Michael J.

    2009-01-01

    C-arm cone beam computed tomography is an advanced 3D imaging technology that is currently available on state-of-the-art flat-panel-based angiography systems. The overlay of cross-sectional imaging information can now be integrated with real-time fluoroscopy. This overlay technology was used to guide the placement of three percutaneous translumbar inferior vena cava catheters.

  12. Quality inspection of concrete

    International Nuclear Information System (INIS)

    Mellmann, G.

    1983-01-01

    The testing instruction named in the pertinent standards for concrete vary considerably. They can best be judged through comparing their operating characteristic curves. Here it is noticed for the proof of the solidity of the building, that with the compressive resistances derived from the impact test, method-related severe variations influence the evaluation of the results. In the scope of tests carried out by the Federal Institute for Material Testing, through non destructive, ultrasonic echo return measurements and impact tests as well as through combined evaluation with the aid of a multiple linear regression analysis, it could be proven that a greater confidence level can be achieved and thus a more appropriate judgement of the quality of the concrete of a building is possible. (orig.) [de

  13. Drilling waste makes concrete

    International Nuclear Information System (INIS)

    Rosfjord, A.

    1993-01-01

    The article deals with a method of drilling waste reclamation by utilizing the converted oil-containing cuttings from the North Sea in the concrete production in Norway. The oil content is to be removed in an incineration process by heating the cuttings to about 800 o C. The output capacity from the exhaust gas water cooling system is 7500 kW/hour, and is to be used in different industrial heating processes. The remaining content of pollutants in the cleaned exhaust gas outlet corresponds to the required limits with the exception of SO 2 and HCl. In addition, an exhaust gas washing plant is to be installed in the near future designed for the further reduction of pollutants by 90%. The converted raw materials are used as a supplement for lessening the demand of sand and cement in the production of concrete-made pipes. 1 fig

  14. Reinforced concrete tomography

    International Nuclear Information System (INIS)

    Mariscotti, M.A.J.; Morixe, M.; Tarela, P.A.; Thieberger, P.

    1997-01-01

    In this paper we describe the technique of reinforced concrete tomography, its historical background, recent technological developments and main applications. Gamma radiation sensitive plates are imprinted with radiation going through the concrete sample under study, and then processed to reveal the presence of reinforcement and defects in the material density. The three dimensional reconstruction, or tomography, of the reinforcement out of a single gammagraphy is an original development alternative to conventional methods. Re-bar diameters and positions may be determined with an accuracy of ± 1 mm 0.5-1 cm, respectively. The non-destructive character of this technique makes it particularly attractive in cases of inhabited buildings and diagnoses of balconies. (author) [es

  15. Hypervelocity impact of concrete

    International Nuclear Information System (INIS)

    Watson, A.J.; Anderson, W.F.; Archer, B.

    1982-01-01

    Blocks of concrete and various other materials were impacted by high speed copper jets at the centre of one face, the resulting transient phenomena were measured using ultra high speed photography and various electrical signal transducers. Measurements were made of the jet velocity, penetration rate, crack velocity and initiation time, and strain pulse propagation. Post test measurements were made using electron microscopy, ultra sonics and stereoscopic photography. (orig.) [de

  16. Design of ultra-lightweight concrete: towards monolithic concrete structures

    Directory of Open Access Journals (Sweden)

    Yu Qing Liang

    2014-04-01

    Full Text Available This study addresses the development of ultra-lightweight concrete. A moderate strength and an excellent thermal conductivity of the lightweight concrete are set as the design targets. The designed lightweight aggregates concrete is targeted to be used in monolithic concrete façade structure, performing as both load bearing element and thermal insulator. The developed lightweight concrete shows excellent thermal properties, with a low thermal conductivity of about 0.12 W/(m·K; and moderate mechanical properties, with 28-day compressive strengths of about 10-12 N/mm . This combination of values exceeds, to the researchers’ knowledge, the performance of all other lightweight building materials. Furthermore, the developed lightweight concrete possesses excellent durability properties.

  17. Interactive overlays: a new method for generating global journal maps from Web-of-Science data

    NARCIS (Netherlands)

    Leydesdorff, L.; Rafols, I.

    2012-01-01

    Recent advances in methods and techniques enable us to develop interactive overlays to a global map of science based on aggregated citation relations among the 9162 journals contained in the Science Citation Index and Social Science Citation Index 2009. We first discuss the pros and cons of the

  18. Improved Intelligent Underlay-Overlay Combined with Frequency Hopping in GSM

    DEFF Research Database (Denmark)

    Wigard, Jeroen; Nielsen, Thomas Toftegaard; Mogensen, Preben Elgaard

    1997-01-01

    IUO (intelligent underlay-overlay) in a combination with random frequency hopping in GSM is analysed. Several improvements to the original IUO concept analysed in Nielsen et al. (1997) are introduced. With the improved IUO concept it is possible to load a network configuration consisting of 4...

  19. Shadow Segmentation and Augmentation Using á-overlay Models that Account for Penumbra

    DEFF Research Database (Denmark)

    Nielsen, Michael; Madsen, Claus B.

    2006-01-01

    that an augmented virtual object can cast an exact shadow. The penumbras (half-shadows) must be taken into account so that we can model the soft shadows.We hope to achieve this by modelling the shadow regions (umbra and penumbra alike) with a transparent overlay. This paper reviews the state-of-the-art shadow...

  20. Effect of SiO2 passivation overlayers on hillock formation in Al thin films

    International Nuclear Information System (INIS)

    Kim, Deok-kee

    2012-01-01

    Hillock formation in Al thin films with varying thicknesses of SiO 2 as a passivation layer was investigated during thermal cycling. Based on the stress measurements and the number of hillocks, 250 nm thick SiO 2 was thick enough to suppress the hillock formation and the suppression of hillock at 250 nm passivation and the lack of suppression at thinner passivation is related to the presence/absence of protection against the diffusive flow of atoms from the surrounding area to the surface due to the biaxial compressive stresses present in the film through the weak spots in the passivation layer. The stress state of Al films measured during annealing (the driving force for hillock formation) did not vary much with SiO 2 thickness. A small number of hillocks formed during the plasma enhanced chemical vapor deposition of SiO 2 overlayers at 300 °C. - Highlights: ► We examined the effect of SiO 2 overlayers on hillock formation in Al thin films. ► Thin overlayers were not effective in suppressing diffusive flow to the surface. ► A thick overlayer suppressed the diffusive flow from the interior to the surface. ► The stress state of Al films did not vary much with SiO 2 passivation thickness. ► High mechanical strength provided a large driving force for the large grain growth.

  1. Posterior open occlusion management by registration of overlay removable partial denture: A clinical report

    Science.gov (United States)

    Nosouhian, Saeid; Davoudi, Amin; Derhami, Mohammad

    2015-01-01

    This clinical report describes prosthetic rehabilitation of posterior open bite relationship in a patient with several missing teeth and skeletal Class III malocclusion. Primary diagnostic esthetic evaluations were performed by mounting casts in centric relation and estimating lost vertical dimension of occlusion. Exclusive treatments were designated by applying overlay removable partial denture with external attachment systems for higher retentions. PMID:26929544

  2. First principles analysis of hydrogen chemisorption on Pd-Re alloyed overlayers and alloyed surfaces

    DEFF Research Database (Denmark)

    Pallassana, Venkataraman; Neurock, Matthew; Hansen, Lars Bruno

    2000-01-01

    Gradient corrected periodic density functional theory (DFT-GGA) slab calculations were used to examine the chemisorption of atomic hydrogen on various Pd-Re alloyed overlayers and uniformly alloyed surfaces. Adsorption was examined at 33% surface coverage, where atomic hydrogen preferred the thre...

  3. Formate stability and carbonate hydrogenation on strained Cu overlayers on Pt(111)

    DEFF Research Database (Denmark)

    Schumacher, Nana Maria Pii; Andersson, Klas Jerker; Nerlov, Jesper

    2008-01-01

    Formate (HCOO) synthesis, decomposition and the hydrogenation of carbonate (CO3) on Cu overlayers deposited on a Pt(111) single crystal are investigated to examine the reactivity of a Cu surface under tensile strain with defects present. Formate is synthesized from a 0.5 bar mixture of 70% CO2...

  4. Multi-wavelength approach towards on-product overlay accuracy and robustness

    Science.gov (United States)

    Bhattacharyya, Kaustuve; Noot, Marc; Chang, Hammer; Liao, Sax; Chang, Ken; Gosali, Benny; Su, Eason; Wang, Cathy; den Boef, Arie; Fouquet, Christophe; Huang, Guo-Tsai; Chen, Kai-Hsiung; Cheng, Kevin; Lin, John

    2018-03-01

    Success of diffraction-based overlay (DBO) technique1,4,5 in the industry is not just for its good precision and low toolinduced shift, but also for the measurement accuracy2 and robustness that DBO can provide. Significant efforts are put in to capitalize on the potential that DBO has to address measurement accuracy and robustness. Introduction of many measurement wavelength choices (continuous wavelength) in DBO is one of the key new capabilities in this area. Along with the continuous choice of wavelengths, the algorithms (fueled by swing-curve physics) on how to use these wavelengths are of high importance for a robust recipe setup that can avoid the impact from process stack variations (symmetric as well as asymmetric). All these are discussed. Moreover, another aspect of boosting measurement accuracy and robustness is discussed that deploys the capability to combine overlay measurement data from multiple wavelength measurements. The goal is to provide a method to make overlay measurements immune from process stack variations and also to report health KPIs for every measurement. By combining measurements from multiple wavelengths, a final overlay measurement is generated. The results show a significant benefit in accuracy and robustness against process stack variation. These results are supported by both measurement data as well as simulation from many product stacks.

  5. Interactive overlay maps for US Patent (USPTO) data based on International Patent Classifications (IPC)

    NARCIS (Netherlands)

    Leydesdorff, L.; Kushnir, D.; Rafols, I.

    2014-01-01

    We report on the development of an interface to the US Patent and Trademark Office (USPTO) that allows for the mapping of patent portfolios as overlays to basemaps constructed from citation relations among all patents contained in this database during the period 1976-2011. Both the interface and the

  6. The Effects of Letter Spacing and Coloured Overlays on Reading Speed and Accuracy in Adult Dyslexia

    Science.gov (United States)

    Sjoblom, Amanda M.; Eaton, Elizabeth; Stagg, Steven D.

    2016-01-01

    Background: Zorzi et al. (2012, Proc. Natl. Acad. Sci. U.S.A., 109, 11455) found evidence that extra-large letter spacing aids children with dyslexia, but the evidence for the coloured overlays is contradictory (e.g., Henderson et al., 2013, "J. Res. Special Educ. Needs," 13, 57; Wilkins, 2002, "Ophthalmic Physiol. Opt.," 22,…

  7. FEM Analysis and Measurement of Residual Stress by Neutron Diffraction on the Dissimilar Overlay Weld Pipe

    International Nuclear Information System (INIS)

    Kim, Kang Soo; Lee, Ho Jin; Woo, Wan Chuck; Seong, Baek Seok; Byeon, Jin Gwi; Park, Kwang Soo; Jung, In Chul

    2010-01-01

    Much research has been done to estimate the residual stress on a dissimilar metal weld. There are many methods to estimate the weld residual stress and FEM (Finite Element Method) is generally used due to the advantage of the parametric study. And the X-ray method and a Hole Drilling technique for an experimental method are also usually used. The aim of this paper is to develop the appropriate FEM model to estimate the residual stresses of the dissimilar overlay weld pipe. For this, firstly, the specimen of the dissimilar overlay weld pipe was manufactured. The SA 508 Gr3 nozzle, the SA 182 safe end and SA376 pipe were welded by the Alloy 182. And the overlay weld by the Alloy 52M was performed. The residual stress of this specimen was measured by using the Neutron Diffraction device in the HANARO (High-flux Advanced Neutron Application ReactOr) research reactor, KAERI (Korea Atomic Energy Research Institute). Secondly, FEM Model on the dissimilar overlay weld pipe was made and analyzed by the ABAQUS Code (ABAQUS, 2004). Thermal analysis and stress analysis were performed, and the residual stress was calculated. Thirdly, the results of the FEM analysis were compared with those of the experimental methods

  8. Fluorogenic membrane overlays to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and seawater

    Science.gov (United States)

    Three assays were developed to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and other foods and in seawater and other environmental samples. Assays involve membrane overlays of overnight colonies on non-selective agar plates to detect ß-glucuronidase and lysyl am...

  9. A study and simulation of the impact of high-order aberrations to overlay error distribution

    Science.gov (United States)

    Sun, G.; Wang, F.; Zhou, C.

    2011-03-01

    With reduction of design rules, a number of corresponding new technologies, such as i-HOPC, HOWA and DBO have been proposed and applied to eliminate overlay error. When these technologies are in use, any high-order error distribution needs to be clearly distinguished in order to remove the underlying causes. Lens aberrations are normally thought to mainly impact the Matching Machine Overlay (MMO). However, when using Image-Based overlay (IBO) measurement tools, aberrations become the dominant influence on single machine overlay (SMO) and even on stage repeatability performance. In this paper, several measurements of the error distributions of the lens of SMEE SSB600/10 prototype exposure tool are presented. Models that characterize the primary influence from lens magnification, high order distortion, coma aberration and telecentricity are shown. The contribution to stage repeatability (as measured with IBO tools) from the above errors was predicted with simulator and compared to experiments. Finally, the drift of every lens distortion that impact to SMO over several days was monitored and matched with the result of measurements.

  10. Diagnostic performance and color overlay pattern in shear wave elastography (SWE) for palpable breast mass.

    Science.gov (United States)

    Park, Jiyoon; Woo, Ok Hee; Shin, Hye Seon; Cho, Kyu Ran; Seo, Bo Kyoung; Kang, Eun Young

    2015-10-01

    The purpose of this study is to evaluate the diagnostic performance of SWE in palpable breast mass and to compare with color overlay pattern in SWE with conventional US and quantitative SWE for assessing palpable breast mass. SWE and conventional breast US were performed in 133 women with 156 palpable breast lesions (81 benign, 75 malignant) between August 2013 to June 2014. Either pathology or periodic imaging surveillance more than 2 years was a reference standard. Existence of previous image was blinded to performing radiologists. US BI-RADS final assessment, qualitative and quantitative SWE measurements were evaluated. Diagnostic performances of grayscale US, SWE and US combined to SWE were calculated and compared. Correlation between pattern classification and quantitative SWE was evaluated. Both color overlay pattern and quantitative SWE improved the specificity of conventional US, from 81.48% to 96.30% (p=0.0005), without improvement in sensitivity. Color overlay pattern was significantly related to all quantitative SWE parameters and malignancy rate (pbreast mass, conventional US combine to SWE improves specificity and reduces the number of biopsies that ultimately yield a benign result. Color overlay pattern classification is more quick and easy and may represent quantitative SWE measurements with similar diagnostic performances. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  11. Science overlay maps: a new tool for research policy and library management

    NARCIS (Netherlands)

    Rafols, I.; Porter, A.L.; Leydesdorff, L.

    2010-01-01

    We present a novel approach to visually locate bodies of research within the sciences, both at each moment of time and dynamically. This article describes how this approach fits with other efforts to locally and globally map scientific outputs. We then show how these science overlay maps help

  12. GROUT-CONCRETE INTERFACE BOND PERFORMANCE: EFFECT OF INTERFACE MOISTURE ON THE TENSILE BOND STRENGTH AND GROUT MICROSTRUCTURE.

    Science.gov (United States)

    De la Varga, I; Muñoz, J F; Bentz, D P; Spragg, R P; Stutzman, P E; Graybeal, B A

    2018-05-01

    Bond between two cementitious materials is crucial in applications such as repairs, overlays, and connections of prefabricated bridge elements (PBEs), to name just a few. It is the latter that has special interest to the authors of this paper. After performing a dimensional stability study on grout-like materials commonly used as connections between PBEs, it was observed that the so-called 'non-shrink' cementitious grouts showed a considerable amount of early-age shrinkage. This might have negative effects on the integrity of the structure, due not only to the grout material's early degradation, but also to a possible loss of bond between the grout and the prefabricated concrete element. Many factors affect the bond strength between two cementitious materials (e.g., grout-concrete), the presence of moisture at the existing concrete substrate surface being one of them. In this regard, pre-moistening the concrete substrate surface prior to the application of the grout material is sometimes recommended for bond enhancement. This topic has been the focus of numerous research studies in the past; however, there is still controversy among practitioners on the real benefits that this practice might provide. This paper evaluates the tensile bond performance of two non-shrink cementitious grouts applied to the exposed aggregate surface of a concrete substrate, and how the supply of moisture at the grout-concrete interface affects the bond strength. "Pull-off" bond results show increased tensile bond strength when the concrete surface is pre-moistened. Reasons to explain the observed increased bond strength are given after a careful microstructural analysis of the grout-concrete interface. Interfaces where sufficient moisture is provided to the concrete substrate such that moisture movement from the grout is prevented show reduced porosity and increased hydration on the grout side of the interface, which is thought to directly contribute to the increased tensile bond

  13. Yield impact for wafer shape misregistration-based binning for overlay APC diagnostic enhancement

    Science.gov (United States)

    Jayez, David; Jock, Kevin; Zhou, Yue; Govindarajulu, Venugopal; Zhang, Zhen; Anis, Fatima; Tijiwa-Birk, Felipe; Agarwal, Shivam

    2018-03-01

    The importance of traditionally acceptable sources of variation has started to become more critical as semiconductor technologies continue to push into smaller technology nodes. New metrology techniques are needed to pursue the process uniformity requirements needed for controllable lithography. Process control for lithography has the advantage of being able to adjust for cross-wafer variability, but this requires that all processes are close in matching between process tools/chambers for each process. When this is not the case, the cumulative line variability creates identifiable groups of wafers1 . This cumulative shape based effect is described as impacting overlay measurements and alignment by creating misregistration of the overlay marks. It is necessary to understand what requirements might go into developing a high volume manufacturing approach which leverages this grouping methodology, the key inputs and outputs, and what can be extracted from such an approach. It will be shown that this line variability can be quantified into a loss of electrical yield primarily at the edge of the wafer and proposes a methodology for root cause identification and improvement. This paper will cover the concept of wafer shape based grouping as a diagnostic tool for overlay control and containment, the challenges in implementing this in a manufacturing setting, and the limitations of this approach. This will be accomplished by showing that there are identifiable wafer shape based signatures. These shape based wafer signatures will be shown to be correlated to overlay misregistration, primarily at the edge. It will also be shown that by adjusting for this wafer shape signal, improvements can be made to both overlay as well as electrical yield. These improvements show an increase in edge yield, and a reduction in yield variability.

  14. Precise X-ray and video overlay for augmented reality fluoroscopy.

    Science.gov (United States)

    Chen, Xin; Wang, Lejing; Fallavollita, Pascal; Navab, Nassir

    2013-01-01

    The camera-augmented mobile C-arm (CamC) augments any mobile C-arm by a video camera and mirror construction and provides a co-registration of X-ray with video images. The accurate overlay between these images is crucial to high-quality surgical outcomes. In this work, we propose a practical solution that improves the overlay accuracy for any C-arm orientation by: (i) improving the existing CamC calibration, (ii) removing distortion effects, and (iii) accounting for the mechanical sagging of the C-arm gantry due to gravity. A planar phantom is constructed and placed at different distances to the image intensifier in order to obtain the optimal homography that co-registers X-ray and video with a minimum error. To alleviate distortion, both X-ray calibration based on equidistant grid model and Zhang's camera calibration method are implemented for distortion correction. Lastly, the virtual detector plane (VDP) method is adapted and integrated to reduce errors due to the mechanical sagging of the C-arm gantry. The overlay errors are 0.38±0.06 mm when not correcting for distortion, 0.27±0.06 mm when applying Zhang's camera calibration, and 0.27±0.05 mm when applying X-ray calibration. Lastly, when taking into account all angular and orbital rotations of the C-arm, as well as correcting for distortion, the overlay errors are 0.53±0.24 mm using VDP and 1.67±1.25 mm excluding VDP. The augmented reality fluoroscope achieves an accurate video and X-ray overlay when applying the optimal homography calculated from distortion correction using X-ray calibration together with the VDP.

  15. Influence of curing time, overlay material and thickness on three light-curing composites used for luting indirect composite restorations.

    Science.gov (United States)

    D'Arcangelo, Camillo; De Angelis, Francesco; Vadini, Mirco; Carluccio, Fabio; Vitalone, Laura Merla; D'Amario, Maurizio

    2012-08-01

    To assess the microhardness of three resin composites employed in the adhesive luting of indirect composite restorations and examine the influence of the overlay material and thickness as well as the curing time on polymerization rate. Three commercially available resin composites were selected: Enamel Plus HRI (Micerium) (ENA), Saremco ELS (Saremco Dental) (SAR), Esthet-X HD (Dentsply/DeTrey) (EST-X). Post-polymerized cylinders of 6 different thicknesses were produced and used as overlays: 2 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, and 6 mm. Two-mm-thick disks were produced and employed as underlays. A standardized amount of composite paste was placed between the underlay and the overlay surfaces which were maintained at a fixed distance of 0.5 mm. Light curing of the luting composite layer was performed through the overlays for 40, 80, or 120 s. For each specimen, the composite to be cured, the cured overlay, and the underlay were made out of the same batch of resin composite. All specimens were assigned to three experimental groups on the basis of the resin composite used, and to subgroups on the basis of the overlay thickness and the curing time, resulting in 54 experimental subgroups (n = 5). Forty-five additional specimens, 15 for each material under investigation, were produced and subjected to 40, 80, or 120 s of light curing using a microscope glass as an overlay; they were assigned to 9 control subgroups (n = 5). Three Vicker's hardness (VH) indentations were performed on each specimen. Means and standard deviations were calculated. Data were statistically analyzed using 3-way ANOVA. Within the same material, VH values lower than 55% of control were not considered acceptable. The used material, the overlay thickness, and the curing time significantly influenced VH values. In the ENA group, acceptable hardness values were achieved with 3.5-mm or thinner overlays after 120 or 80 s curing time (VH 41.75 and 39.32, respectively), and with 2-mm overlays after 40 s (VH 54

  16. Operational features of decorative concrete

    Science.gov (United States)

    Bazhenova, Olga; Kotelnikov, Maxim

    2018-03-01

    This article deals with the questions of creation and use of decorative and finishing concrete and mortar. It has been revealed that the most effective artificial rock-imitating stone materials are those made of decorative concrete with the opened internal structure of material. At the same time it is important that the particles of decorative aggregate should be distributed evenly in the concrete volume. It can be reached only at a continuous grain-size analysis of the aggregate from the given rock. The article tackles the necessity of natural stone materials imitation for the cement stone color to correspond to the color of the rock. The possibility of creation of the decorative concrete imitating rocks in the high-speed turbulent mixer is considered. Dependences of durability and frost resistance of the studied concrete on the pore size and character and also parameters characterizing crack resistance of concrete are received.

  17. Concrete workability and fibre content

    OpenAIRE

    Vikan, Hedda

    2007-01-01

    Research report Parameters influencing the workability of fibre concrete and maximum fibre content are given in this state of the art report along with the range of fibre types available on today’s market. The study reveales that new placing techniques and production methods are crucial in order to increase fibre content and concrete strength. Achieving the same mechanical properties as traditionally reinforced concrete will probably also demand changes of the matrix. Finally, reco...

  18. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In this paper an optimal inspection strategy for concrete bridges based on periodic routine and detailed inspections is presented. The failure mode considered is corrosion of the reinforcement due to chlorides. A simple modelling of the corrosion and of the inspection strategy is presented....... The optimal inspection strategy is determined from an optimization problem, where the design variables are time intervals between detailed inspections and the concrete cover. The strategy is illustrated on a simple structure, namely a reinforced concrete beam....

  19. Another Concrete In the Wall

    OpenAIRE

    Meric, Asli Duru

    2015-01-01

    concrete has a memory. It stores the construction sequences. It shows what it is made of and how it is made. The texture of the formwork, the color difference of the pours, and the shadows of the metal ties combine to layer the beauty of concrete. The aim of this study is to explore the instruments of a concrete surface in order to enhance this multi-sensory experience. This study began with the design of a concrete wall and evolved into the design of a single-family home. MARCH

  20. Build-up Factor Calculation for Ordinary Concrete, Baryte Concrete and Blast-furnace Slugges Concrete as γ Radiation Shielding

    International Nuclear Information System (INIS)

    Isman MT; Elisabeth Supriatni; Tochrul Binowo

    2002-01-01

    Calculation of build up factor ordinary concrete, baryte concrete and blast-furnace sludge concrete have been carried out. The calculations have been carried out by dose rate measurement of Cs 137 source before and after passing through shielding. The investigated variables were concrete type, thickness of concrete and relative possession of concrete. Concrete type variables are ordinary concrete, baryte concrete and blast sludge furnace concrete. The thickness variables were 6, 12, 18, 24, 30 and 36 cm. The relative position variables were dose to the source and close to detector. The result showed that concrete type and position did not have significant effect to build-up factor value, while the concrete thickness (r) and the attenuation coefficient (μ) were influenced to the build-up factor. The higher μr value the higher build-up factor value. (author)

  1. Two Dimensional Array Based Overlay Network for Balancing Load of Peer-to-Peer Live Video Streaming

    Science.gov (United States)

    Faruq Ibn Ibrahimy, Abdullah; Rafiqul, Islam Md; Anwar, Farhat; Ibn Ibrahimy, Muhammad

    2013-12-01

    The live video data is streaming usually in a tree-based overlay network or in a mesh-based overlay network. In case of departure of a peer with additional upload bandwidth, the overlay network becomes very vulnerable to churn. In this paper, a two dimensional array-based overlay network is proposed for streaming the live video stream data. As there is always a peer or a live video streaming server to upload the live video stream data, so the overlay network is very stable and very robust to churn. Peers are placed according to their upload and download bandwidth, which enhances the balance of load and performance. The overlay network utilizes the additional upload bandwidth of peers to minimize chunk delivery delay and to maximize balance of load. The procedure, which is used for distributing the additional upload bandwidth of the peers, distributes the additional upload bandwidth to the heterogeneous strength peers in a fair treat distribution approach and to the homogeneous strength peers in a uniform distribution approach. The proposed overlay network has been simulated by Qualnet from Scalable Network Technologies and results are presented in this paper.

  2. Two Dimensional Array Based Overlay Network for Balancing Load of Peer-to-Peer Live Video Streaming

    International Nuclear Information System (INIS)

    Ibrahimy, Abdullah Faruq Ibn; Rafiqul, Islam Md; Anwar, Farhat; Ibrahimy, Muhammad Ibn

    2013-01-01

    The live video data is streaming usually in a tree-based overlay network or in a mesh-based overlay network. In case of departure of a peer with additional upload bandwidth, the overlay network becomes very vulnerable to churn. In this paper, a two dimensional array-based overlay network is proposed for streaming the live video stream data. As there is always a peer or a live video streaming server to upload the live video stream data, so the overlay network is very stable and very robust to churn. Peers are placed according to their upload and download bandwidth, which enhances the balance of load and performance. The overlay network utilizes the additional upload bandwidth of peers to minimize chunk delivery delay and to maximize balance of load. The procedure, which is used for distributing the additional upload bandwidth of the peers, distributes the additional upload bandwidth to the heterogeneous strength peers in a fair treat distribution approach and to the homogeneous strength peers in a uniform distribution approach. The proposed overlay network has been simulated by Qualnet from Scalable Network Technologies and results are presented in this paper

  3. Effect of preemptive weld overlay sequence on residual stress distribution for dissimilar metal weld of Kori nuclear power plant pressurizer

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Hong Yeol; Song, Tae Kwang; Chun, Yun Bae; Oh, Chang Young; Kim, Yun Jae [Korea Univ., Seoul (Korea, Republic of); Lee, Kyoung Soo; Park, Chi Yong [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

    2008-07-01

    Weld overlay is one of the residual stress mitigation method which arrest crack. An overlay weld sued in this manner is termed a Preemptive Weld OverLay(PWOL). PWOL was good for distribution of residual stress of Dissimilar Metal Weld(DMW) by previous research. Because range of overlay welding is wide relatively, residual stress distribution on PWR is affected by welding sequence. In order to examine the effect of welding sequence, PWOL was applied to a specific DMW of KORI nuclear power plant by finite element analysis method. As a result, the welding direction that from nozzle to pipe is better good for residual stress distribution on PWR.

  4. Effect of preemptive weld overlay sequence on residual stress distribution for dissimilar metal weld of Kori nuclear power plant pressurizer

    International Nuclear Information System (INIS)

    Bae, Hong Yeol; Song, Tae Kwang; Chun, Yun Bae; Oh, Chang Young; Kim, Yun Jae; Lee, Kyoung Soo; Park, Chi Yong

    2008-01-01

    Weld overlay is one of the residual stress mitigation method which arrest crack. An overlay weld sued in this manner is termed a Preemptive Weld OverLay(PWOL). PWOL was good for distribution of residual stress of Dissimilar Metal Weld(DMW) by previous research. Because range of overlay welding is wide relatively, residual stress distribution on PWR is affected by welding sequence. In order to examine the effect of welding sequence, PWOL was applied to a specific DMW of KORI nuclear power plant by finite element analysis method. As a result, the welding direction that from nozzle to pipe is better good for residual stress distribution on PWR

  5. Characterisation and management of concrete grinding residuals.

    Science.gov (United States)

    Kluge, Matt; Gupta, Nautasha; Watts, Ben; Chadik, Paul A; Ferraro, Christopher; Townsend, Timothy G

    2018-02-01

    Concrete grinding residue is the waste product resulting from the grinding, cutting, and resurfacing of concrete pavement. Potential beneficial applications for concrete grinding residue include use as a soil amendment and as a construction material, including as an additive to Portland cement concrete. Concrete grinding residue exhibits a high pH, and though not hazardous, it is sufficiently elevated that precautions need to be taken around aquatic ecosystems. Best management practices and state regulations focus on reducing the impact on such aquatic environment. Heavy metals are present in concrete grinding residue, but concentrations are of the same magnitude as typically recycled concrete residuals. The chemical composition of concrete grinding residue makes it a useful product for some soil amendment purposes at appropriate land application rates. The presence of unreacted concrete in concrete grinding residue was examined for potential use as partial replacement of cement in new concrete. Testing of Florida concrete grinding residue revealed no dramatic reactivity or improvement in mortar strength.

  6. The influence of recycled concrete aggregates in pervious concrete

    Directory of Open Access Journals (Sweden)

    L. M. TAVARES

    Full Text Available The expansion of urban areas under constant changes in the hydrological cycle directly affects the drainage of rainwater. The problems of urban drainage become major engineering problems to be solved in order to avoid negative consequences for local populations. Another urban problem is the excessive production of construction and demolition waste (CDW, in which , even with a increasingly policy of waste management , have been an end up being thrown in inappropriate disposal sites. Alternatively aiming to a minimization of the problems presented, we propose the study of permeable concrete using recycled concrete aggregate. In this study, there were evaluated the performance of concrete by means of permeability, consistency, strength, and interface conditions of the materials . Satisfactory relationships of resistance/permeability of concrete with recycled aggregate in relation to the concrete with natural aggregates was obtained, showing their best potential.

  7. C-arm cone beam computed tomography needle path overlay for fluoroscopic guided vertebroplasty.

    Science.gov (United States)

    Tam, Alda L; Mohamed, Ashraf; Pfister, Marcus; Chinndurai, Ponraj; Rohm, Esther; Hall, Andrew F; Wallace, Michael J

    2010-05-01

    Retrospective review. To report our early clinical experience using C-arm cone beam computed tomography (C-arm CBCT) with fluoroscopic overlay for needle guidance during vertebroplasty. C-arm CBCT is advanced three-dimensional (3-D) imaging technology that is currently available on state-of-the-art flat panel based angiography systems. The imaging information provided by C-arm CBCT allows for the acquisition and reconstruction of "CT-like" images in flat panel based angiography/interventional suites. As part of the evolution of this technology, enhancements allowing the overlay of cross-sectional imaging information can now be integrated with real time fluoroscopy. We report our early clinical experience with C-arm CBCT with fluoroscopic overlay for needle guidance during vertebroplasty. This is a retrospective review of 10 consecutive oncology patients who underwent vertebroplasty of 13 vertebral levels using C-arm CBCT with fluoroscopic overlay for needle guidance from November 2007 to December 2008. Procedural data including vertebral level, approach (transpedicular vs. extrapedicular), access (bilateral vs. unilateral) and complications were recorded. Technical success with the overlay technology was assessed based on accuracy which consisted of 4 measured parameters: distance from target to needle tip, distance from planned path to needle tip, distance from midline to needle tip, and distance from the anterior 1/3 of the vertebral body to needle tip. Success within each parameter required that the distance between the needle tip and parameter being evaluated be no more than 5 mm on multiplanar CBCT or fluoroscopy. Imaging data for 12 vertebral levels was available for review. All vertebral levels were treated using unilateral access and 9 levels were treated with an extrapedicular approach. Technical success rates were 92% for both distance from planned path and distance from midline to final needle tip, 100% when distance from needle tip to the anterior 1

  8. Nuclear radiation and the properties of concrete

    International Nuclear Information System (INIS)

    Kaplan, M.F.

    1983-08-01

    Concrete is used for structures in which the concrete is exposed to nuclear radiation. Exposure to nuclear radiation may affect the properties of concrete. The report mentions the types of nuclear radiation while radiation damage in concrete is discussed. Attention is also given to the effects of neutron and gamma radiation on compressive and tensile strength of concrete. Finally radiation shielding, the attenuation of nuclear radiation and the value of concrete as a shielding material is discussed

  9. The concrete canister program

    International Nuclear Information System (INIS)

    Ohta, M.M.

    1978-02-01

    In the spring of 1974, WNRE began development and demonstration of a dry storage concept, called the concrete canister, as a possible alternative to storage of irradiated CANDU fuel in water pools. The canister is a thick-walled concrete monolith containing baskets of fuel in the dry state. The decay heat from the fuel is dissipated to the environment by natural heat transfer. Four canisters were designed and constructed. Two canisters containing electric heaters have been subjected to heat loads of 2.5 times the design, ramp heat-load cycling, and simulated weathering tests. The other two canisters were loaded with irradiated fuel, one containing fuel bundles of uniform decay heat and the other containing bundles of non-uniform decay heat in a non-symmetrical radial and axial array. The collected data were used to verify the analytical tools for prediction of effectiveness of heat transfer and radiation shielding and to verify the design of the basket and canisters. The demonstration canisters have shown that this concept is a viable alternative to water pools for the storage of irradiated CANDU fuel. (author)

  10. The Concrete and Pavement Challenge

    Science.gov (United States)

    Roman, Harry T.

    2012-01-01

    The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as…

  11. Revised Rules for Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Jensen, F. M.; Middleton, C.

    This paper is based on research performed for the Highway Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: Concrete Bridges" It contains details of a methodology which can be used to generate Whole Life (WL) reliability profiles....... These WL reliability profiles may be used to establish revised rules for Concrete Bridges....

  12. Proportioning of light weight concrete

    DEFF Research Database (Denmark)

    Palmus, Lars

    1996-01-01

    Development of a method to determine the proportions of the raw materials in light weight concrete made with leight expanded clay aggregate. The method is based on composite theory......Development of a method to determine the proportions of the raw materials in light weight concrete made with leight expanded clay aggregate. The method is based on composite theory...

  13. Fatigue of Concrete Armour Units

    DEFF Research Database (Denmark)

    Sørensen, N. B.; Burcharth, H. F.; Liu, Z.

    1995-01-01

    In the present article fatigue as a possible reason for failure of Dolosse armour units made of plain concrete is discussed.......In the present article fatigue as a possible reason for failure of Dolosse armour units made of plain concrete is discussed....

  14. Concrete for γ radiation shielding

    International Nuclear Information System (INIS)

    Azevedo e Souza, A.C. de; Rogers, John Douglas

    1980-01-01

    The attenuation characteristics of γ radiation in concrete slabs, considering their mechanical resistence and densities were determined. One heavy concrete which was used, was prepared using as additives iron ore and Fe 2 O 3 pellets in various grain sizes. Fortran programs were used for analysing data and determining the absorption coefficients and attenuation factors. (Author) [pt

  15. Radiographic testing in concrete structures

    International Nuclear Information System (INIS)

    Oliveira, D. de

    1987-01-01

    The radiographic testing done in concrete structures is used to analyse the homogeneity, position and corrosion of armatures and to detect discontinuity in the concrete such as: gaps, cracks and segregations. This work develops a Image quality Indicator (IQI) with an adequated sensibility to detect discontinuites based on BS4408 norm. (E.G.) [pt

  16. Wood and concrete polymer composites

    International Nuclear Information System (INIS)

    Singer, K.

    1974-01-01

    There are several ways to prepare and use wood and concrete polymer composites. The most important improvements in the case of concrete polymer composites are obtained for compressive and tensile strengths. The progress in this field in United States and other countries is discussed in this rview. (M.S.)

  17. Concrete for. gamma. radiation shielding

    Energy Technology Data Exchange (ETDEWEB)

    de Azevedo e Souza, A.C. (Rio de Janeiro Univ. (Brazil). Inst. de Quimica); Rogers, J D [Rio de Janeiro Univ. (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia

    1980-06-01

    The attenuation characteristics of ..gamma.. radiation in concrete slabs, considering their mechanical resistence and densities were determined. One heavy concrete which was used, was prepared using as additives iron ore and Fe/sub 2/ O/sub 3/ pellets in various grain sizes. Fortran programs were used for analysing data and determining the absorption coefficients and attenuation factors.

  18. Concrete shielding exterior to iron

    International Nuclear Information System (INIS)

    Yurista, P.; Cossairt, D.

    1983-08-01

    A rule of thumb at Fermilab has been to use 3 feet of concrete exterior to iron shielding. A recent design of a shield with a severe dimensional constraint has prompted a re-evaluation of this rule of thumb and has led to the following calculations of the concrete thickness required to nullify this problem. 4 references, 4 figures

  19. Urban heritage, building maintenance : Concrete

    NARCIS (Netherlands)

    Verhoef, L.G.W.

    1999-01-01

    Concrete as a conglomerate of sand, stone and a binder, is a very old material indeed. In the Roman period earth from Puozzoli, together with lime and water could bind the sand and the stones to form a conglomerate that has an affmity to our modem concrete. Later, in the more northem areas of

  20. Concrete Operations and Attentional Capacity.

    Science.gov (United States)

    Chapman, Michael; Lindenberger, Ulman

    1989-01-01

    To test predictions regarding the attentional capacity requirements of Piaget's stage of concrete operations, a battery of concrete operational tasks and two measures of attentional capacity were administered to 120 first-, second-, and third-graders. Findings concern class inclusion, transitivity of length and weight, and multiplication of…

  1. Shear reinforced beams in autoclaved aerated concrete

    DEFF Research Database (Denmark)

    Cornelius, Thomas

    2010-01-01

    Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different combinat....... Codes for designing prefabricated reinforced components of aircrete structures have adopted these recently developed approaches.......Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different...

  2. Novel techniques for concrete curing

    DEFF Research Database (Denmark)

    Kovler, Konstantin; Jensen, Ole Mejlhede

    2005-01-01

    It is known that some high-strength/high-performance concretes (HSC/HPC) are prone to cracking at an early age unless special precautions are taken. The paper deals with the methods of curing as one of the main strategies to ensure good performance of concrete. Curing by both external (conventional......) and internal methods is reviewed and analyzed, among other methods of mitigating shrinkage and cracking of concrete. The focus is on the mitigation of autogenous shrinkage of low water to binder ratio (w/b) concrete by means of internal curing. The concepts of internal curing are based on using lightweight...... aggregate, superabsorbent polymers or water-soluble chemicals, which reduce water evaporation (so called "internal sealing"). These concepts have been intensively researched in the 90s, but still are not widespread among contractors and concrete suppliers. The differences between conventional methods...

  3. Basic principles of concrete structures

    CERN Document Server

    Gu, Xianglin; Zhou, Yong

    2016-01-01

    Based on the latest version of designing codes both for buildings and bridges (GB50010-2010 and JTG D62-2004), this book starts from steel and concrete materials, whose properties are very important to the mechanical behavior of concrete structural members. Step by step, analysis of reinforced and prestressed concrete members under basic loading types (tension, compression, flexure, shearing and torsion) and environmental actions are introduced. The characteristic of the book that distinguishes it from other textbooks on concrete structures is that more emphasis has been laid on the basic theories of reinforced concrete and the application of the basic theories in design of new structures and analysis of existing structures. Examples and problems in each chapter are carefully designed to cover every important knowledge point. As a basic course for undergraduates majoring in civil engineering, this course is different from either the previously learnt mechanics courses or the design courses to be learnt. Compa...

  4. Sodium concrete reaction - Structural considerations

    International Nuclear Information System (INIS)

    Ferskakis, G.N.

    1984-01-01

    An overview of the sodium concrete reaction phenomenon, with emphasis on structural considerations, is presented. Available test results for limestone, basalt, and magnetite concrete with various test article configurations are reviewed. Generally, tests indicate reaction is self limiting before all sodium is used. Uncertainties, however, concerning the mechanism for penetration of sodium into concrete have resulted in different theories about a reaction model. Structural behavior may be significant in the progression of the reaction due to thermal-structuralchemical interactions involving tensile cracking, compressive crushing, or general deterioration of concrete and the exposure of fresh concrete surfaces to react with sodium. Structural behavior of test articles and potential factors that could enhance the progression of the reaction are discussed

  5. Concrete poetry in three languages

    Directory of Open Access Journals (Sweden)

    Aleksandra Kremer

    2013-01-01

    Full Text Available This paper analyzes different paths of the development of both the movement and the notion of concrete poetry in three linguistic regions. The German-language konkrete Dichtung turns out to usually denote the original, historical shape of the movement, which was partly created in German- speaking countries and which has been treated as a literary phenomenon. The Englishlanguage term concrete poetry is a much broader category which also encompasses visual poetry and avant-garde texts that are distant from the sources of concretism in its early form. The Polish understanding of ‘poezja konkretna’ [concrete poetry] was influenced by both German- and English- language books and by the movement’s regional version, which appeared in Poland as late as in the 1970s. The selected linguistic areas allowed the author to show three basic ways of thinking about concretism, i.e. about its initial, international, and regional versions.

  6. Impact of organic overlayers on a-Si:H/c-Si surface potential

    KAUST Repository

    Seif, Johannes P.

    2017-04-11

    Bilayers of intrinsic and doped hydrogenated amorphous silicon, deposited on crystalline silicon (c-Si) surfaces, simultaneously provide contact passivation and carrier collection in silicon heterojunction solar cells. Recently, we have shown that the presence of overlaying transparent conductive oxides can significantly affect the c-Si surface potential induced by these amorphous silicon stacks. Specifically, deposition on the hole-collecting bilayers can result in an undesired weakening of contact passivation, thereby lowering the achievable fill factor in a finished device. We test here a variety of organic semiconductors of different doping levels, overlaying hydrogenated amorphous silicon layers and silicon-based hole collectors, to mitigate this effect. We find that these materials enhance the c-Si surface potential, leading to increased implied fill factors. This opens opportunities for improved device performance.

  7. Nickel-base alloy overlay weld with improved ultrasonic flaw detection by magnetic stirring welding

    International Nuclear Information System (INIS)

    Takashi, Hirano; Kenji, Hirano; Masayuki, Watando; Takahiro, Arakawa; Minoru, Maeda

    2001-01-01

    Ultrasonic flaw detection is more difficult in Nickel-base alloy welds containing dendrites owing to the decrease ultrasonic transmissibility they cause. The present paper discusses application of magnetic stirring welding as a means for reducing dendrite growth with consequent improvement in ultrasonic transmissibility. Single pass and multi-pass welding tests were conducted to determine optimal welding conditions. By PT and macro observation subsequent to welding was carried out, optimal operation conditions were clarified. Overlay welding tests and UT clearly indicated ultrasonic beam transmissibility in overlay welds to be improved and detection capacity to be greater through application of magnetic stirring welding. Optimal operation conditions were determined based on examination of temper bead effects in the heat affected zone of low alloy steel by application of magnetic stirring welding to the butt welded joints between low alloy and stainless steel. Hardness in this zone of low alloy steel after the fourth layer was less than 350 HV. (author)

  8. A Hybrid P2P Overlay Network for Non-strictly Hierarchically Categorized Content

    Science.gov (United States)

    Wan, Yi; Asaka, Takuya; Takahashi, Tatsuro

    In P2P content distribution systems, there are many cases in which the content can be classified into hierarchically organized categories. In this paper, we propose a hybrid overlay network design suitable for such content called Pastry/NSHCC (Pastry for Non-Strictly Hierarchically Categorized Content). The semantic information of classification hierarchies of the content can be utilized regardless of whether they are in a strict tree structure or not. By doing so, the search scope can be restrained to any granularity, and the number of query messages also decreases while maintaining keyword searching availability. Through simulation, we showed that the proposed method provides better performance and lower overhead than unstructured overlays exploiting the same semantic information.

  9. EPES information depth for an overlayer/substrate system with a diffuse interface

    International Nuclear Information System (INIS)

    Zommer, L.

    2009-01-01

    The information depth (ID) of elastic peak electron spectroscopy (EPES) was considered for an overlayer/substrate system with a diffuse interface. The interface was assumed to have an exponential concentration profile. The paradox previously found by Zommer and Jablonski for the Rh/Al and Al/Rh systems with sharp interfaces also occurs for these systems with diffuse interfaces. We compared IDs for diffuse and sharp interfaces. Deviations between the IDs depend on the interface width, overlayer thickness, and selected system for a given primary energy (here 2000 eV). The deviations for the Rh/Al and Al/Rh systems differ profoundly. These results are of importance when interpreting EPES measurements of layered system

  10. A Secure and Stable Multicast Overlay Network with Load Balancing for Scalable IPTV Services

    Directory of Open Access Journals (Sweden)

    Tsao-Ta Wei

    2012-01-01

    Full Text Available The emerging multimedia Internet application IPTV over P2P network preserves significant advantages in scalability. IPTV media content delivered in P2P networks over public Internet still preserves the issues of privacy and intellectual property rights. In this paper, we use SIP protocol to construct a secure application-layer multicast overlay network for IPTV, called SIPTVMON. SIPTVMON can secure all the IPTV media delivery paths against eavesdroppers via elliptic-curve Diffie-Hellman (ECDH key exchange on SIP signaling and AES encryption. Its load-balancing overlay tree is also optimized from peer heterogeneity and churn of peer joining and leaving to minimize both service degradation and latency. The performance results from large-scale simulations and experiments on different optimization criteria demonstrate SIPTVMON's cost effectiveness in quality of privacy protection, stability from user churn, and good perceptual quality of objective PSNR values for scalable IPTV services over Internet.

  11. Variables affecting viral plaque formation in microculture plaque assays using homologous antibody in a liquid overlay.

    Science.gov (United States)

    Randhawa, A S; Stanton, G J; Green, J A; Baron, S

    1977-05-01

    A liquid antibody microculture plaque assay and the variables that govern its effectiveness are described. The assay is based on the principle that low concentrations of homologous antibody can inhibit secondary plaque formation without inhibiting formation of primary plaques. Thus, clear plaques that followed a linear dose response were produced. The assay was found to be more rapid, less cumbersome, and less expensive than assays using agar overlays and larger tissue culture plates. It was reproducible, quantitative, and had about the same sensitivity as the agar overlay technique in measuring infectious coxsackievirus type B-3. It was more sensitive in assaying adenovirus type 3 and Western equine encephalomyelitis, vesicular stomatitis, Semliki forest, Sendai, Sindbis, and Newcastle disease viruses than were liquid, carboxymethylcellulose, and methylcellulose microculture plaque assays. The variables influencing sensitivity and accuracy, as determined by using coxsackievirus type B-3, were: (i) the inoculum volume of virus; (ii) the incubation period of virus; and (iii) the incubation temperature.

  12. Combined Conjunctival Autograft and Overlay Amniotic Membrane Transplantation; a Novel Surgical Treatment for Pterygium

    Directory of Open Access Journals (Sweden)

    Siamak Zarei Ghanavati

    2014-01-01

    Full Text Available The authors report the long-term results of combined conjunctival autograft and overlay amniotic membrane transplantation (AMT for treatment of pterygium as a new surgical technique. Nineteen patients including 12 male and 7 female subjects with pterygium (primary, 14 cases; recurrent, 5 cases underwent combined conjunctival autograft and overlay AMT and were followed from 10 to 26 months. Mean age was 44.21±12.49 (range, 29.0-73.0 years. In one patient with grade T3 primary pterygium, the lesion recurred (5.2%, recurrence rate. No intra-and postoperative complication developed. This procedure seems a safe and effective surgical technique for pterygium treatment. Protection of the ocular surface during the early postoperative period reduces the friction-induced inflammation and might be helpful to prevent the recurrence.

  13. Impact of organic overlayers on a-Si:H/c-Si surface potential

    KAUST Repository

    Seif, Johannes P.; Niesen, Bjoern; Tomasi, Andrea; Ballif, Christophe; De Wolf, Stefaan

    2017-01-01

    Bilayers of intrinsic and doped hydrogenated amorphous silicon, deposited on crystalline silicon (c-Si) surfaces, simultaneously provide contact passivation and carrier collection in silicon heterojunction solar cells. Recently, we have shown that the presence of overlaying transparent conductive oxides can significantly affect the c-Si surface potential induced by these amorphous silicon stacks. Specifically, deposition on the hole-collecting bilayers can result in an undesired weakening of contact passivation, thereby lowering the achievable fill factor in a finished device. We test here a variety of organic semiconductors of different doping levels, overlaying hydrogenated amorphous silicon layers and silicon-based hole collectors, to mitigate this effect. We find that these materials enhance the c-Si surface potential, leading to increased implied fill factors. This opens opportunities for improved device performance.

  14. Impact of Improper Gaussian Signaling on the Achievable Rate of Overlay Cognitive Radio

    KAUST Repository

    Amin, Osama

    2017-05-12

    Improper Gaussian signaling (IGS) has been recently shown to provide performance improvements in underlay cognitive radio systems as opposed to the conventional proper Gaussian signaling (PGS) scheme. For the first time, this paper implements IGS scheme in overlay cognitive radio system, where the secondary transmitter broadcasts a mixture of two different signals. The first signal is selected from the PGS scheme to support the primary message transmission. On the other hand, the second signal is chosen to be from the IGS scheme in order to reduce the interference effect on the primary receiver. We then optimally design the overlay cognitive radio that employs IGS to maximize the secondary link achievable rate while satisfying the minimum rate requirement of the primary network. In particular, we derive closed form expressions for the circularity coefficient used in the IGS scheme and the power distribution parameters. Simulation results are provided to support our theoretical derivations.

  15. Impact of Improper Gaussian Signaling on the Achievable Rate of Overlay Cognitive Radio

    KAUST Repository

    Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

    2017-01-01

    Improper Gaussian signaling (IGS) has been recently shown to provide performance improvements in underlay cognitive radio systems as opposed to the conventional proper Gaussian signaling (PGS) scheme. For the first time, this paper implements IGS scheme in overlay cognitive radio system, where the secondary transmitter broadcasts a mixture of two different signals. The first signal is selected from the PGS scheme to support the primary message transmission. On the other hand, the second signal is chosen to be from the IGS scheme in order to reduce the interference effect on the primary receiver. We then optimally design the overlay cognitive radio that employs IGS to maximize the secondary link achievable rate while satisfying the minimum rate requirement of the primary network. In particular, we derive closed form expressions for the circularity coefficient used in the IGS scheme and the power distribution parameters. Simulation results are provided to support our theoretical derivations.

  16. Surface crystallographic structures of cellulose nanofiber films and overlayers of pentacene

    Science.gov (United States)

    Nakayama, Yasuo; Mori, Toshiaki; Tsuruta, Ryohei; Yamanaka, Soichiro; Yoshida, Koki; Imai, Kento; Koganezawa, Tomoyuki; Hosokai, Takuya

    2018-03-01

    Cellulose nanofibers or nanocellulose is a promising recently developed biomass and biodegradable material used for various applications. In order to utilize this material as a substrate in organic electronic devices, thorough understanding of the crystallographic structures of the surfaces of the nanocellulose composites and of their interfaces with organic semiconductor molecules is essential. In this work, surface crystallographic structures of nanocellulose films (NCFs) and overlayers of pentacene were investigated by two-dimensional grazing-incidence X-ray diffraction. The NCFs are found to crystallize on solid surfaces with the crystal lattice preserving the same structure of the known bulk phase, whereas distortion of interchain packing toward the surface normal direction is suggested. The pentacene overlayers on the NCFs are found to form the thin-film phase with an in-plane mean crystallite size of over 10 nm.

  17. NDT with the structural weld overlay program. Recent field experience and lessons learned

    International Nuclear Information System (INIS)

    Rishel, R.; Lenz, H.; Turley, G.; Newton, B.

    2007-01-01

    Structural weld overlay (SWOL) has become a predominant mitigation technique within the Alloy 600 program. For the pressurizer nozzles, MRP-139 requires volumetric examination by year end 2007. Many nozzles are un-inspectable due to geometry and material limitations that preclude interrogation of the required examination volume. SWOL therefore is the mitigation technique which overcomes these limitations. SWOL of the pressurizer nozzles has been a challenge for all the vendors. Alloy 52 has proven to be difficult to weld under field conditions. The NDT technique chosen to demonstrate the integrity of the overlay needs to be adapted to the specific repair process and nozzle geometry. The purpose of this paper will be to present Westinghouse's integrated approach for SWOL with the focus on the NDT aspects. Topics will include main repair process steps, NDT qualification, recent field experience and lessons learned. (author)

  18. Nuclear Power Plant Concrete Structures

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Prabir [International Atomic Energy Agency (IAEA); Labbe, Pierre [Electricity of France (EDF); Naus, Dan [Oak Ridge National Laboratory (ORNL)

    2013-01-01

    A nuclear power plant (NPP) involves complex engineering structures that are significant items of the structures, systems and components (SSC) important to the safe and reliable operation of the NPP. Concrete is the commonly used civil engineering construction material in the nuclear industry because of a number of advantageous properties. The NPP concrete structures underwent a great degree of evolution, since the commissioning of first NPP in early 1960. The increasing concern with time related to safety of the public and environment, and degradation of concrete structures due to ageing related phenomena are the driving forces for such evolution. The concrete technology underwent rapid development with the advent of chemical admixtures of plasticizer/super plasticizer category as well as viscosity modifiers and mineral admixtures like fly ash and silica fume. Application of high performance concrete (HPC) developed with chemical and mineral admixtures has been witnessed in the construction of NPP structures. Along with the beneficial effect, the use of admixtures in concrete has posed a number of challenges as well in design and construction. This along with the prospect of continuing operation beyond design life, especially after 60 years, the impact of extreme natural events ( as in the case of Fukushima NPP accident) and human induced events (e.g. commercial aircraft crash like the event of September 11th 2001) has led to further development in the area of NPP concrete structures. The present paper aims at providing an account of evolution of NPP concrete structures in last two decades by summarizing the development in the areas of concrete technology, design methodology and construction techniques, maintenance and ageing management of concrete structures.

  19. POROUS STRUCTURE OF ROAD CONCRETE

    Directory of Open Access Journals (Sweden)

    M. K. Pshembaev

    2016-01-01

    Full Text Available Having a great number of concrete structure classifications it is recommended to specify the following three principal types: microstructure – cement stone structure; mesostructure – structure of cement-sand mortar in concrete; macrostucture – two-component system that consists of mortar and coarse aggregate. Every mentioned-above structure has its own specific features which are related to the conditions of their formation. Thus, microstructure of cement stone can be characterized by such structural components as crystal intergrowth, tobermorite gel, incompletely hydrated cement grains and porous space. The most important technological factors that influence on formation of cement stone microstructure are chemical and mineralogical cement composition, its grinding fineness, water-cement ratio and curing condition. Specific cement stone microstructure is formed due to interrelation of these factors. Cement stone is a capillary-porous body that consists of various solid phases represented predominantly by sub-microcrystals of colloidal dispersion. The sub-microcrystals are able adsorptively, osmotically and structurally to withhold (to bind some amount of moisture. Protection of road concrete as a capillary-porous body is considered as one of the topical issues. The problem is solved with the help of primary and secondary protection methods. Methods of primary protection are used at the stage of designing, preparation and placing of concrete. Methods of secondary protection are applied at the operational stage of road concrete pavement. The paper considers structures of concrete solid phase and characteristics of its porous space. Causes of pore initiation, their shapes, dimensions and arrangement in the concrete are presented in the paper. The highest hazard for road concrete lies in penetration of aggressive liquid in it and moisture transfer in the cured concrete. Water permeability of concrete characterizes its filtration factor which

  20. In-die photomask registration and overlay metrology with PROVE using 2D correlation methods

    Science.gov (United States)

    Seidel, D.; Arnz, M.; Beyer, D.

    2011-11-01

    According to the ITRS roadmap, semiconductor industry drives the 193nm lithography to its limits, using techniques like double exposure, double patterning, mask-source optimization and inverse lithography. For photomask metrology this translates to full in-die measurement capability for registration and critical dimension together with challenging specifications for repeatability and accuracy. Especially, overlay becomes more and more critical and must be ensured on every die. For this, Carl Zeiss SMS has developed the next generation photomask registration and overlay metrology tool PROVE® which serves the 32nm node and below and which is already well established in the market. PROVE® features highly stable hardware components for the stage and environmental control. To ensure in-die measurement capability, sophisticated image analysis methods based on 2D correlations have been developed. In this paper we demonstrate the in-die capability of PROVE® and present corresponding measurement results for shortterm and long-term measurements as well as the attainable accuracy for feature sizes down to 85nm using different illumination modes and mask types. Standard measurement methods based on threshold criteria are compared with the new 2D correlation methods to demonstrate the performance gain of the latter. In addition, mask-to-mask overlay results of typical box-in-frame structures down to 200nm feature size are presented. It is shown, that from overlay measurements a reproducibility budget can be derived that takes into account stage, image analysis and global effects like mask loading and environmental control. The parts of the budget are quantified from measurement results to identify critical error contributions and to focus on the corresponding improvement strategies.

  1. Microeconomics-based resource allocation in overlay networks by using non-strategic behavior modeling

    Science.gov (United States)

    Analoui, Morteza; Rezvani, Mohammad Hossein

    2011-01-01

    Behavior modeling has recently been investigated for designing self-organizing mechanisms in the context of communication networks in order to exploit the natural selfishness of the users with the goal of maximizing the overall utility. In strategic behavior modeling, the users of the network are assumed to be game players who seek to maximize their utility with taking into account the decisions that the other players might make. The essential difference between the aforementioned researches and this work is that it incorporates the non-strategic decisions in order to design the mechanism for the overlay network. In this solution concept, the decisions that a peer might make does not affect the actions of the other peers at all. The theory of consumer-firm developed in microeconomics is a model of the non-strategic behavior that we have adopted in our research. Based on it, we have presented distributed algorithms for peers' "joining" and "leaving" operations. We have modeled the overlay network as a competitive economy in which the content provided by an origin server can be viewed as commodity and the origin server and the peers who multicast the content to their downside are considered as the firms. On the other hand, due to the dual role of the peers in the overlay network, they can be considered as the consumers as well. On joining to the overlay economy, each peer is provided with an income and tries to get hold of the service regardless to the behavior of the other peers. We have designed the scalable algorithms in such a way that the existence of equilibrium price (known as Walrasian equilibrium price) is guaranteed.

  2. Material development for waste to energy plants. Overlay welding and refractory linings. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Noergaard Hansson, A.

    2011-02-15

    Waste is an extremely corrosive fuel. In order to recover a higher percentage of the energy in waste, waste incineration plants have developed from purely heat producing units to heat and power producing units. The change in concept results in higher material temperatures and thereby faster material degradation. As a result material failures have been observed in many waste incineration plants. The purpose of this project was to develop materials with higher resistance to the corrosive elements, in order to reduce the cost of maintenance, increase the availability, and increase the efficiency. The focus is on overlay welding and refractory linings. Inconel 625, alloy 50, alloy 686, and Super 625 offer equivalent corrosion protection at panel walls. 100% overlay performs better than 50% overlay. The corrosion morphology changes with increasing temperature from pitting and general corrosion to pitting and selective corrosion (dendritic core or grain boundaries). The previously observed detrimental effect of Fe on the corrosion resistance was not confirmed. It probably depends on factors such as microstructure of the alloy and local metal temperature. Ni-overlay also reduces the corrosion rates on superheater tubes. However, the superheater environment is less aggressive than the water wall environment. Failure of refractory linings is linked to excess porosity, detrimental reactions between raw materials and other mix constituents, volume growth reactions between base material and salt depositions, and thermal stress induced crack formation. Free water and not decomposition of hydrates causes spalling and cracking during the initial heating of refractory linings. Finite Element analysis confirms the stress levels between steel and refractory with the higher stress level at the top of the panel wall tube. A number of LCC mixes were formulated, adjusted and tested. Mixes with low open porosities ({approx} 10%) and state of the art resistance to KCl were achieved. (LN)

  3. Ab initio study of Co and Ni under uniaxial and biaxial loading and in epitaxial overlayers

    Czech Academy of Sciences Publication Activity Database

    Zelený, Martin; Legut, Dominik; Šob, Mojmír

    2008-01-01

    Roč. 78, č. 22 (2008), 224105/1-224105/11 ISSN 1098-0121 R&D Projects: GA ČR GD106/05/H008; GA AV ČR IAA1041302; GA MŠk OC 147 Institutional research plan: CEZ:AV0Z20410507 Keywords : ab initio calculations * epitaxial overlayers * uniaxial and biaxial loading Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.322, year: 2008

  4. Clinical Applications of a CT Window Blending Algorithm: RADIO (Relative Attenuation-Dependent Image Overlay).

    Science.gov (United States)

    Mandell, Jacob C; Khurana, Bharti; Folio, Les R; Hyun, Hyewon; Smith, Stacy E; Dunne, Ruth M; Andriole, Katherine P

    2017-06-01

    A methodology is described using Adobe Photoshop and Adobe Extendscript to process DICOM images with a Relative Attenuation-Dependent Image Overlay (RADIO) algorithm to visualize the full dynamic range of CT in one view, without requiring a change in window and level settings. The potential clinical uses for such an algorithm are described in a pictorial overview, including applications in emergency radiology, oncologic imaging, and nuclear medicine and molecular imaging.

  5. Texas flexible pavements and overlays : year 1 report, test sections, data collection, analyses, and data storage system.

    Science.gov (United States)

    2012-06-01

    This five-year project was initiated to collect materials and pavement performance data on a minimum of 100 highway test sections around the State of Texas, incorporating both flexible pavements and overlays. Besides being used to calibrate and valid...

  6. Properties of concretes produced with waste concrete aggregate

    International Nuclear Information System (INIS)

    Topcu, Ilker Bekir; Sengel, Selim

    2004-01-01

    An environmentally friendly approach to the disposal of waste materials, a difficult issue to cope with in today's world, would only be possible through a useful recycling process. For this reason, we suggest that clearing the debris from destroyed buildings in such a way as to obtain waste concrete aggregates (WCA) to be reused in concrete production could well be a partial solution to environmental pollution. For this study, the physical and mechanical properties along with their freeze-thaw durability of concrete produced with WCAs were investigated and test results presented. While experimenting with fresh and hardened concrete, mixtures containing recycled concrete aggregates in amounts of 30%, 50%, 70%, and 100% were prepared. Afterward, these mixtures underwent freeze-thaw cycles. As a result, we found out that C16-quality concrete could be produced using less then 30% C14-quality WCA. Moreover, it was observed that the unit weight, workability, and durability of the concretes produced through WCA decreased in inverse proportion to their endurance for freeze-thaw cycle

  7. Numerical evaluation of weld overlay applied to a pressurized water reactor nozzle mock-up

    Energy Technology Data Exchange (ETDEWEB)

    Rabello, Emerson G.; Silva, Luiz L.; Gomes, Paulo T.V., E-mail: egr@cdtn.b, E-mail: silvall@cdtn.b, E-mail: gomespt@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Integridade Estrutural

    2011-07-01

    The primary water stress corrosion cracking (PWSCC) is a major mechanism of failure in the primary circuit of PWR type nuclear power plants. The PWSCC is associated with the presence of corrosive environment, the susceptibility to corrosion cracking of the materials involved and the tensile stresses presence. Residual stresses generated during dissimilar materials welding can contribute to PWSCC. An alternative to the PWSCC mitigation is the application of external weld layers in the regions of greatest susceptibility to corrosion cracking. This process, called Weld Overlay (WOL), has been widely used in regions of dissimilar weld (low alloy steel and stainless steel with nickel alloy addition) of nozzles and pipes on the primary circuit in order to promote internal compressive stresses on the wall of these components. This paper presents the steps required to the numerical stress evaluation (by finite element method) during the dissimilar materials welding as well as application of Weld Overlay process in a nozzle mock-up. Thus, one can evaluate the effectiveness of the application of weld overlay process to internal compressive stress generation on the wall nozzle. (author)

  8. Numerical evaluation of weld overlay applied to a pressurized water reactor nozzle mock-up

    International Nuclear Information System (INIS)

    Rabello, Emerson G.; Silva, Luiz L.; Gomes, Paulo T.V.

    2011-01-01

    The primary water stress corrosion cracking (PWSCC) is a major mechanism of failure in the primary circuit of PWR type nuclear power plants. The PWSCC is associated with the presence of corrosive environment, the susceptibility to corrosion cracking of the materials involved and the tensile stresses presence. Residual stresses generated during dissimilar materials welding can contribute to PWSCC. An alternative to the PWSCC mitigation is the application of external weld layers in the regions of greatest susceptibility to corrosion cracking. This process, called Weld Overlay (WOL), has been widely used in regions of dissimilar weld (low alloy steel and stainless steel with nickel alloy addition) of nozzles and pipes on the primary circuit in order to promote internal compressive stresses on the wall of these components. This paper presents the steps required to the numerical stress evaluation (by finite element method) during the dissimilar materials welding as well as application of Weld Overlay process in a nozzle mock-up. Thus, one can evaluate the effectiveness of the application of weld overlay process to internal compressive stress generation on the wall nozzle. (author)

  9. Hydrogen absorption kinetics of niobium with an ion-plated nickel overlayer

    International Nuclear Information System (INIS)

    Nakamura, K.

    1981-01-01

    The hydrogen absorption rate for nickel-ion-plated niobium was measured as a function of hydrogen pressure and temperature. The observed absorption curves of c(mean)/csub(e) against time (c(mean) and csub(e) are the mean and equilibrium hydrogen concentrations respectively) exhibited a marked hydrogen pressure dependence below 628 K but this was less marked above 723 K. The results were analysed on the basis of the proposed model that the rate-determining step is the hydrogen permeation through the nickel overlayer and that the permeation is driven by the hydrogen activity difference between the two interfaces, namely the H 2 -Ni and Ni-Nb interfaces. The marked pressure dependence can be attributed to the fact that the hydrogen activity coefficient in nickel is constant and that in niobium it varies markedly with concentration, i.e. with hydrogen pressure and temperature. It was also found that the change in the nickel overlayer structure caused by the dilatation of bulk niobium during hydrogen absorption enhances the hydrogen absorption rates. The temperature dependence of the hydrogen absorption rate is also discussed in comparison with that for tantalum with a vacuum-deposited nickel overlayer. (Auth.)

  10. Visual supports for shared reading with young children: the effect of static overlay design.

    Science.gov (United States)

    Wood Jackson, Carla; Wahlquist, Jordan; Marquis, Cassandra

    2011-06-01

    This study examined the effects of two types of static overlay design (visual scene display and grid display) on 39 children's use of a speech-generating device during shared storybook reading with an adult. This pilot project included two groups: preschool children with typical communication skills (n = 26) and with complex communication needs (n = 13). All participants engaged in shared reading with two books using each visual layout on a speech-generating device (SGD). The children averaged a greater number of activations when presented with a grid display during introductory exploration and free play. There was a large effect of the static overlay design on the number of silent hits, evidencing more silent hits with visual scene displays. On average, the children demonstrated relatively few spontaneous activations of the speech-generating device while the adult was reading, regardless of overlay design. When responding to questions, children with communication needs appeared to perform better when using visual scene displays, but the effect of display condition on the accuracy of responses to wh-questions was not statistically significant. In response to an open ended question, children with communication disorders demonstrated more frequent activations of the SGD using a grid display than a visual scene. Suggestions for future research as well as potential implications for designing AAC systems for shared reading with young children are discussed.

  11. Iron aluminide weld overlay coatings for boiler tube protection in coal-fired low NOx boilers

    Energy Technology Data Exchange (ETDEWEB)

    Banovic, S.W.; DuPont, J.N.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center

    1997-12-01

    Iron aluminide weld overlay coatings are currently being considered for enhanced sulfidation resistance in coal-fired low NO{sub x} boilers. The use of these materials is currently limited due to hydrogen cracking susceptibility, which generally increases with an increase in aluminum concentration of the deposit. The overall objective of this program is to attain an optimum aluminum content with good weldability and improved sulfidation resistance with respect to conventional materials presently in use. Research has been initiated using Gas Tungsten Arc Welding (GTAW) in order to achieve this end. Under different sets of GTAW parameters (wire feed speed, current), both single and multiple pass overlays were produced. Characterization of all weldments was conducted using light optical microscopy, scanning electron microscopy, and electron probe microanalysis. Resultant deposits exhibited a wide range of aluminum contents (5--43 wt%). It was found that the GTAW overlays with aluminum contents above {approximately}10 wt% resulted in cracked coatings. Preliminary corrosion experiments of 5 to 10 wt% Al cast alloys in relatively simple H{sub 2}/H{sub 2}S gas mixtures exhibited corrosion rates lower than 304 stainless steel.

  12. He atom-surface scattering: Surface dynamics of insulators, overlayers and crystal growth

    International Nuclear Information System (INIS)

    Safron, S.A.; Skofronick, J.G.

    1994-01-01

    This progress report describes work carried out in the study of surface structure and dynamics of ionic insulators, the microscopic interactions controlling epitaxial growth and the formation of overlayers, and energy exchange in multiphonon surface scattering. The approach used is to employ high resolution helium atom scattering to study the geometry and structural features of the surfaces. Experiments have been carried out on the surface dynamics of RbCl and preliminary studies done on CoO and NiO. Epitaxial growth and overlayer dynamics experiments on the systems NaCl/NaCl(001), KBr/NaCl(001), NaCl/KBr(001) and KBr/RbCl(001) have been performed. They have collaborated with two theoretical groups to explore models of overlayer dynamics with which to compare and to interpret their experimental results. They have carried out extensive experiments on the multiphonon scattering of helium atoms from NaCl and, particularly, LiF. Work has begun on self-assembling organic films on gold and silver surfaces (alkyl thiols/Au(111) and Ag(111))

  13. Magnetism of CrO overlayers on Fe(001)bcc surface: first principles calculations

    Science.gov (United States)

    Félix-Medina, Raúl Enrique; Leyva-Lucero, Manuel Andrés; Meza-Aguilar, Salvador; Demangeat, Claude

    2018-04-01

    Riva et al. [Surf. Sci. 621, 55 (2014)] as well as Calloni et al. [J. Phys.: Condens. Matter 26, 445001 (2014)] have studied the oxydation of Cr films deposited on Fe(001)bcc through low-energy electron diffraction, Auger electron spectroscopy and scanning tunneling microscopy. In the present work we perform a density functional approach within Quantum Expresso code in order to study structural and magnetic properties of CrO overlayers on Fe(001)bcc. The calculations are performed using DFT+U. The investigated systems include O/Cr/Fe(001)bcc, Cr/O/Fe(001)bcc, Cr0.25O0.75/Fe(001)bcc, as well as the O coverage Ox/Cr/Fe(001)bcc (x = 0.25; 0.50). We have found that the ordered CrO overlayer presents an antiferromagnetic coupling between Cr and Fe atoms. The O atoms are located closer to the Fe atoms of the surface than the Cr atoms. The ground state of the systems O/Cr/Fe(001)bcc and Cr/O/Fe(001)bcc corresponds to the O/Cr/Fe(001)bcc system with a magnetic coupling c(2 × 2). The effect of the O monolayer on Cr/Fe(001)bcc changes the ground state from p(1 × 1) ↓ to c(2 × 2) and produces an enhancement of the magnetic moments. The Ox overlayer on Cr/Fe(001)bcc produces an enhancement of the Cr magnetic moments.

  14. SIMULATION MODELS OF RESISTANCE TO CONCRETE MOVEMENT IN THE CONCRETE CONVEYING PIPE OF THE AUTOCONCRETE PUMP

    OpenAIRE

    Anofriev, P. G.

    2015-01-01

    Purpose. In modern construction the placing of concrete is often performed using distribution equipment of concrete pumps. Increase of productivity and quality of this construction work requires improvement of both concrete pumps and their tooling. The concrete pumps tooling consists of standardized concrete conveying pipes and connector bends radius of up to 2 m. A promising direction of tooling improvement is the reduce of resistance to movement of the concrete in the concrete conveying pip...

  15. Three-dimensional magnetic resonance imaging overlay to assist with percutaneous transhepatic access at the time of cardiac catheterization

    Directory of Open Access Journals (Sweden)

    Wendy Whiteside

    2015-01-01

    Full Text Available Multimodality image overlay is increasingly used for complex interventional procedures in the cardiac catheterization lab. We report a case in which three-dimensional magnetic resonance imaging (3D MRI overlay onto live fluoroscopic imaging was utilized to safely obtain transhepatic access in a 12-year-old patient with prune belly syndrome, complex and distorted abdominal anatomy, and a vascular mass within the liver.

  16. Three-dimensional magnetic resonance imaging overlay to assist with percutaneous transhepatic access at the time of cardiac catheterization

    International Nuclear Information System (INIS)

    Whiteside, Wendy; Christensen, Jason; Zampi, Jeffrey D

    2005-01-01

    Multimodality image overlay is increasingly used for complex interventional procedures in the cardiac catheterization lab. We report a case in which three-dimensional magnetic resonance imaging (3D MRI) overlay onto live fluoroscopic imaging was utilized to safely obtain transhepatic access in a 12-year-old patient with prune belly syndrome, complex and distorted abdominal anatomy, and a vascular mass within the liver

  17. Image-based overlay and alignment metrology through optically opaque media with sub-surface probe microscopy

    Science.gov (United States)

    van Es, Maarten H.; Mohtashami, Abbas; Piras, Daniele; Sadeghian, Hamed

    2018-03-01

    Nondestructive subsurface nanoimaging through optically opaque media is considered to be extremely challenging and is essential for several semiconductor metrology applications including overlay and alignment and buried void and defect characterization. The current key challenge in overlay and alignment is the measurement of targets that are covered by optically opaque layers. Moreover, with the device dimensions moving to the smaller nodes and the issue of the so-called loading effect causing offsets between between targets and product features, it is increasingly desirable to perform alignment and overlay on product features or so-called on-cell overlay, which requires higher lateral resolution than optical methods can provide. Our recently developed technique known as SubSurface Ultrasonic Resonance Force Microscopy (SSURFM) has shown the capability for high-resolution imaging of structures below a surface based on (visco-)elasticity of the constituent materials and as such is a promising technique to perform overlay and alignment with high resolution in upcoming production nodes. In this paper, we describe the developed SSURFM technique and the experimental results on imaging buried features through various layers and the ability to detect objects with resolution below 10 nm. In summary, the experimental results show that the SSURFM is a potential solution for on-cell overlay and alignment as well as detecting buried defects or voids and generally metrology through optically opaque layers.

  18. Visually assessed colour overlay features in shear-wave elastography for breast masses: quantification and diagnostic performance.

    Science.gov (United States)

    Gweon, Hye Mi; Youk, Ji Hyun; Son, Eun Ju; Kim, Jeong-Ah

    2013-03-01

    To determine whether colour overlay features can be quantified by the standard deviation (SD) of the elasticity measured in shear-wave elastography (SWE) and to evaluate the diagnostic performance for breast masses. One hundred thirty-three breast lesions in 119 consecutive women who underwent SWE before US-guided core needle biopsy or surgical excision were analysed. SWE colour overlay features were assessed using two different colour overlay pattern classifications. Quantitative SD of the elasticity value was measured with the region of interest including the whole breast lesion. For the four-colour overlay pattern, the area under the ROC curve (Az) was 0.947; with a cutoff point between pattern 2 and 3, sensitivity and specificity were 94.4 % and 81.4 %. According to the homogeneity of the elasticity, the Az was 0.887; with a cutoff point between reasonably homogeneous and heterogeneous, sensitivity and specificity were 86.1 % and 82.5 %. For the SD of the elasticity, the Az was 0.944; with a cutoff point of 12.1, sensitivity and specificity were 88.9 % and 89.7 %. The colour overlay features showed significant correlations with the quantitative SD of the elasticity (P < 0.001). The colour overlay features and the SD of the elasticity in SWE showed excellent diagnostic performance and showed good correlations between them.

  19. 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)

  20. Monitoring device for reinforced concrete

    International Nuclear Information System (INIS)

    Matsuzaki, Tetsuo; Saito, Koichi; Furukawa, Hideyasu.

    1994-01-01

    A reactor container made of reinforced concretes is monitored for the temperature at each of portions upon placing concretes under construction of a plant, upon pressure-proof test and during plant operation. That is, optical fibers are uniformly laid spirally throughout the inside of the concretes. Pulses are injected from one end of the optical fibers, and the temperature at a reflection point can be measured by measuring specific rays (Raman scattering rays) among lights reflected after a predetermined period of time. According to the present invention, measurement for an optional position within a range where one fiber cable is laid can be conducted. Accordingly, it is possible to conduct temperature control upon concrete placing and apply temperature compensation for the measurement for stresses of the concretes and the reinforcing steels upon container pressure-proof. Further, during plant operation, if the temperature of the concretes rises due to thermal conduction of the temperature in the container, integrity of the concretes can be ensured by a countermeasures such as air conditioning. (I.S.)

  1. Long-life concrete : how long will my concrete last?

    Science.gov (United States)

    2013-10-01

    There is an ongoing discussion about moving toward performance-based specifications for concrete pavements. This document seeks to : move the discussion forward by outlining the needs and the challenges, and proposing some immediate actions. However,...

  2. Urban Experiments and Concrete Utopias

    DEFF Research Database (Denmark)

    Andersson, Lasse

    2009-01-01

    The paper explores how concrete urban experiments can challenge the pecuniary version of the experience city and stimulate a locally rooted and democratic version of an experience based city using heterotopias and concrete utopias as the link between top down planning and bottom up experiments...... administrations with public participation in order to shape a cultural agenda. The second part of the paper looks at two cases: NDSM in Amsterdam and Platform4 in Aalborg suggesting that it is concrete urban experiments like these that can create a link between visions and local reality in the Experience city...

  3. PCM Concrete. [Phase Change Materials

    Energy Technology Data Exchange (ETDEWEB)

    Juul Andersen, T. [Danish Technological Institute, Taastrup (Denmark); Poulsen, H.-H. [BASF A/S, Roedekro (Denmark); Passov, F. [Spaencom A/S, Hedehusene (Denmark); Heiselberg, P. [Aalborg Univ..Aalborg (Denmark)

    2013-04-01

    PCM-Concrete was a research and development project launched in 2009 and finished in 2012. The project, which was funded by The Danish National Advanced Technology Foundation, had a total budget of 1.7 million Euros and included 4 partners: Danish Technological Institute (project manager), Aalborg University, BASF A/S and Spaencom A/S. The overall vision of the project was to reduce energy consumption for heating and cooling in buildings by developing high-performance concrete structures microencapsulated Phase Change Materials (PCM). The PCM used in the project was Micronal produced by BASF A/S. Micronal is small capsules with an acrylic shell and inside a wax with a melting point at approx. 23 deg. C equal to a comfortable indoor temperature. During the melting process thermal energy is transferred to chemical reaction (melting/solidification) depending on PCM being heated up or cooled down. Adding Micronal to concrete would theoretically increase the thermal mass of the concrete and improve the diurnal heat capacity which is the amount of energy that can be stored and released during 24 hours. Nevertheless, it is a relatively new technology that has not received much attention, yet. In the PCM-Concrete project 5 main investigations were carried out: 1) Development of concrete mix design with PCM. 2) Investigation of thermal properties of the PCM concrete: thermal conductivity, specific heat capacity, density. 3) Up-scaling the research to industrial production of PCM-concrete structures. 4) Testing energy efficiency in full scale. 5) Confronting aesthetic and acoustic barriers to full exploitation of the potential of PCM-concrete structures. The results from the test program showed: 1) That the diurnal heat storage capacity is higher for all 4 hollow core decks with tiles attached compared to the reference hollow core deck. 2) The hollow core decks with concrete tiles without PCM performs slightly better than the tiles with PCM. 3) That is was impossible to

  4. Corrosion resistance and microstructure of alloy 625 weld overlay on ASTM A516 grade 70

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Mohammad J. [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Petroleum Engineering Dept.; Ketabchi, Mostafa [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Mining and Metallurgical Engineering Dept.

    2016-02-01

    Nickel-based alloys are a crucial class of materials because of their excellent corrosion resistance. In the present study, single layer and two layers alloy 625 weld overlays were deposited by GTAW process on A516 grade 70 carbon steel. The dilution in terms of Fe, Ni, Mo and Nb content was calculated in 30 points of weld overlay. Microstructure observations showed that alloy 625 had austenitic structure with two types of Laves and NbC secondary phases. The uniform and pitting corrosion resistance of alloy 625 weld overlay as casted and as forged were evaluated in accordance with ASTM G48-2011 standard at different temperatures to determine the weight loss and critical pitting temperature. For achieving a better comparison, samples from alloy 625 as casted and as forged were tested under the same conditions. The results point out that single layer alloy 625 weld overlay is not suitable for chloride containing environments, two layers alloy 625 weld overlay and alloy 625 as casted have acceptable corrosion resistance and almost the same critical pitting temperature. Alloy 625 as forged has the best corrosion resistance and the highest critical pitting temperature among all test specimens. Also, the corrosion behavior was evaluated in accordance with ASTM G28 standard. The corrosion rate of single layer weld overlay was unacceptable. The average corrosion rate of two layers weld overlay and in casted condition were 35.82 and 33.01 mpy, respectively. [German] Nickellegierungen sind aufgrund ihres exzellenten Korrosionswiderstandes eine bedeutende Werkstoffklasse. In der diesem Beitrag zugrunde liegenden Studie wurden mittels WIG-Schweissens ein- und zweilagige Schweissplattierungen auf den Kohlenstoffstahl A516 (Grade 70) aufgebracht. Die Vermischung in Form des Fe-, Ni-, Mo- und Nb-Gehaltes wurde an 30 Punkten der Schweissplattierungen berechnet. Die mikrostrukturellen Untersuchungen ergaben, dass die Legierung 625 eine austenitische Struktur mit zwei Arten von

  5. Review of concrete properties for prestressed concrete pressure vesssels

    International Nuclear Information System (INIS)

    Nanstad, R.K.

    1976-10-01

    The desire for increasing power output along with safety requirements has resulted in consideration of the prestressed concrete pressure vessel (PCPV) for most current nuclear reactor systems, as well as for the very-high-temperature reactor for process heat and as primary pressure vessels for coal conversion systems. Results are presented of a literature review to ascertain current knowledge regarding plain concrete properties under conditions imposed by a mass concrete structure such as PCRV. The effects of high temperature on such properties as strength, elasticity, and creep are discussed, as well as changes in thermal properties, multiaxial behavior, and the mechanisms thought to be responsible for the observed behavior. In addition, the effects of radiation and moisture migration are discussed. It is concluded that testing results found in the technical literature show much disagreement as to the effects of temperature on concrete properties. The variations in concrete mixtures, curing and testing procedures, age at loading, and moisture conditions during exposure and testing are some of the reasons for such disagreement. Test results must be limited, in most cases, to the materials and conditions of a given test rather than applied to such a general class of materials such as concrete. It is also concluded that sustained exposure of normal concretes to current PCRV operating conditions will not result in any significant loss of properties. However, lack of knowledge regarding effects of temperatures exceeding 100 0 C (212 0 F), moisture migration, and multiaxial behavior precludes a statement advocating operation beyond current design limits. The report includes recommendations for future research on concrete for PCPVs

  6. Betonreparationers holdbarhed (Durability of Concrete Repairs)

    DEFF Research Database (Denmark)

    Brimnes, Eydbjørn; Dali, Bogi í; Larsen, Erik Stoklund

    1999-01-01

    Concrete repairs on 11 pillars on bridges built in the sixties and repaired 8 to 9 years ago have been examined. Especially the chloride penetration in the repair concrete have been measured. Chloride penetration in the repair concrete is much lower than in the original concrete....

  7. Biaxial Stress Tests of Plain Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.K.; Cho, M.S.; Song, Y.C. [Korea Electric Power Research Institute, Taejon (Korea)

    2001-07-01

    Containment concrete specimens(4000, 5000psi) were tested under biaxial stress and presented basic physical properties and biaxial failure envelops for the concrete specimens. Failure behaviors of concrete under biaxial stress were assessed with stress-strain responses and failure modes. Here provided real test data to develop nonlinear finite element concrete models. (author). 15 refs., 46 figs., 4 tabs.

  8. 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...

  9. Rotational Capacity of Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Ulfkjær, J. P.; Henriksen, M. S.; Brincker, Rune

    1995-01-01

    programme where 120 reinforced concrete beams, 54 plain concrete beams and 324 concrete cylinders are tested. For the reinforced concrete beams four different parar meters are varied. The slenderness is 6, 12 and 18, the beam depth is 100 mm, 200 mm and 400 mm giving nine different geometries, five...

  10. A multifunctional design approach for sustainable concrete : with application to concrete mass products

    NARCIS (Netherlands)

    Hüsken, G.

    2010-01-01

    This thesis provides a multifunctional design approach for sustainable concrete, particularly earth-moist concrete (EMC), with application to concrete mass products. EMC is a concrete with low water content and stiff consistency that is used for the production of concrete mass products, such as

  11. Towards Better Understanding of Concrete Containing Recycled Concrete Aggregate

    Directory of Open Access Journals (Sweden)

    Hisham Qasrawi

    2013-01-01

    Full Text Available The effect of using recycled concrete aggregates (RCA on the basic properties of normal concrete is studied. First, recycled aggregate properties have been determined and compared to those of normal aggregates. Except for absorption, there was not a significant difference between the two. Later, recycled aggregates were introduced in concrete mixes. In these mixes, natural coarse aggregate was partly or totally replaced by recycled aggregates. Results show that the use of recycled aggregates has an adverse effect on the workability and air content of fresh concrete. Depending on the water/cement ratio and on the percent of the normal aggregate replaced by RCA, the concrete strength is reduced by 5% to 25%, while the tensile strength is reduced by 4% to 14%. All results are compared with previous research. As new in this research, the paper introduces a simple formula for the prediction of the modulus of elasticity of RCA concrete. Furthermore, the paper shows the variation of the air content of RAC.

  12. Concrete density estimation by rebound hammer method

    International Nuclear Information System (INIS)

    Ismail, Mohamad Pauzi bin; Masenwat, Noor Azreen bin; Sani, Suhairy bin; Mohd, Shukri; Jefri, Muhamad Hafizie Bin; Abdullah, Mahadzir Bin; Isa, Nasharuddin bin; Mahmud, Mohamad Haniza bin

    2016-01-01

    Concrete is the most common and cheap material for radiation shielding. Compressive strength is the main parameter checked for determining concrete quality. However, for shielding purposes density is the parameter that needs to be considered. X- and -gamma radiations are effectively absorbed by a material with high atomic number and high density such as concrete. The high strength normally implies to higher density in concrete but this is not always true. This paper explains and discusses the correlation between rebound hammer testing and density for concrete containing hematite aggregates. A comparison is also made with normal concrete i.e. concrete containing crushed granite

  13. Nondestructive testing of concrete structures

    International Nuclear Information System (INIS)

    Rufino, Randy R.; Relunia, Estrella

    1999-01-01

    Nondestructive testing of concrete is highly inhomogeneous which makes it cumbersome to setup experimental procedures and analyze experimental data. However, recent research and development activities have discovered the different methods of NDT, like the electromagnetic method, ultrasonic pulse velocity test, pulse echo/impact echo test, infrared thermography, radar or short pulse radar techniques, neutron and gamma radiometry, radiography, carbonation test and half-cell potential method available for NDT of concrete structures. NDT of concrete is emerging as a useful tool for quality control and assurance. This papers also describes the more common NDT methods discussed during the two-week course on 'Nondestructive Testing of Concrete Structures', held at the Malaysian Institute for Nuclear Technology Research (MINT) in Malaysia, which was jointly organized by MINT and the International Atomic Energy Agency (IAEA)

  14. Tests on standard concrete samples

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

    Compression and tensile tests on standard concrete samples. The use of centrifugal force in tensile testing has been developed by the SB Division and the instruments were built in the Central workshops.

  15. Sustainable concretes for transportation infrastructure.

    Science.gov (United States)

    2010-07-01

    performance in concrete for structural and transportation applications. Based on the challenges associated with coal ash (including SDA) and the economic costs linked to cement production, this research seeks to develop an environmentally friendly an...

  16. Monitoring water loss form fresh concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede

    2006-01-01

    Desiccation of concrete before or during setting may lead to detrimental plastic shrinkage cracking in the concrete surface zone. Cracking due to plastic shrinkage is a major technological problem for any concrete, however, modern high-performance concretes are especially susceptible to this...... determination of the evaporation loss from hardening concrete and thus better possibility for preventing curing problems, including detrimental crack damage due to plastic shrinkage....

  17. Modelling reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, Mette Rica; Stang, Henrik

    2012-01-01

    A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold......, a numerical example is pre-sented, that illustrates the formation of corrosion cells as well as propagation of corrosion in a reinforced concrete structure....

  18. Electrically conductive polymer concrete coatings

    Science.gov (United States)

    Fontana, Jack J.; Elling, David; Reams, Walter

    1990-01-01

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  19. Annotated Bibliography: Polymers in Concrete.

    Science.gov (United States)

    1982-10-01

    Berka , L., "Determination of the Creeping and Relaxation Functions . from the Results of the Creeping and Relaxation Tests," RILE. Symposium on Synthetic...However, for both foamed glass and . Mearlcrete concretes the agreement between prediction and experiment is not too bad . The reason for the serious...chemical resistance of various concretes is in the following order: (good) PIAC > AC > WCC ( bad ). The aggressive chemical agents that attack markedly

  20. Concrete with supplementary cementitious materials

    OpenAIRE

    Jensen, Ole M; Kovler, Konstantin; De Belie, Nele

    2016-01-01

    This volume contains the proceedings of the MSSCE 2016 conference segment on “Concrete with Supplementary Cementitious Materials” (SCM). The conference segment is organized by the RILEM technical committee TC 238-SCM: Hydration and microstructure of concrete with supplementary cementitious materials. TC 238-SCM started activities in 2011 and has about 50 members from all over the world. The main objective of the committee is to support the increasing utilisation of hydraulic...

  1. Porous Structure of Road Concrete

    OpenAIRE

    Пшембаев, М. К.; Гиринский, В. В.; Ковалев, Я. Н.; Яглов, В. Н.; Будниченко, С. С.

    2016-01-01

    Having a great number of concrete structure classifications it is recommended to specify the following three principal types: microstructure – cement stone structure; mesostructure – structure of cement-sand mortar in concrete; macrostucture – two-component system that consists of mortar and coarse aggregate. Every mentioned-above structure has its own specific features which are related to the conditions of their formation. Thus, microstructure of cement stone can be characterized by such st...

  2. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; Ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Concrete waste reduction of 50%

    International Nuclear Information System (INIS)

    Vos, R.M. de; Van der Wagt, K.M.; Van der Kruk, E.; Meeussen, H.W.

    2016-01-01

    During decommissioning quite a volume of concrete waste is produced. The degree of activation of the waste can range from clearly activated material to slightly activated or contaminated concrete. The degree of activation influences the applicable waste management processes that can be applied. The subsequent waste management processes can be identified for concrete waste are; disposal, segregation, re-use, conditional release and release. With each of these steps, the footprint of radioactive decommissioning waste is reduced. Future developments for concrete waste reduction can be achieved by applying smart materials in new build facilities (i.e. fast decaying materials). NRG (Nuclear Research and consultancy Group) has investigated distinctive waste management processes to reduce the foot-print of concrete waste streams resulting from decommissioning. We have investigated which processes can be applied in the Netherlands, both under current legislation and with small changes in legislation. We have also investigated the separation process in more detail. Pilot tests with a newly patented process have been started in 2015. We expect that our separation methods will reduce the footprint reduction of concrete waste by approximately 50% due to release or re-use in the nuclear sector or in the conventional industry. (authors)

  4. Effects of layering technique on the shade of resin overlays and the microhardness of dual cure resin cement

    Directory of Open Access Journals (Sweden)

    Hoon-Sang Chang

    2014-06-01

    Full Text Available The purpose of this study was to assess the color of layered resin overlays and to test the early microhardness of dual cure resin cement (DCRC light cured through the layered resin overlays. Resin overlays of 1.5 mm thickness were fabricated with the A3 shade of Z350 (Group 1L, the A3B and A3E shades of Supreme XT (Group 2L, and the A3, E3, and T1 shades of Sinfony (Group 3L using one, two, and three layers, respectively (n = 7. Each layer of the resin overlays was set in equal thickness. The color of the resin overlays was measured with a colorimeter and compared with an A3 shade resin denture tooth. DCRC was light cured through the resin overlays, and the early microhardness of the DCRC was measured. The ΔE value between the denture tooth and the resin overlays and the Vickers hardness number (VHN of the DCRC were analyzed with one-way ANOVA and Tukey’s HSD test. The color differences were 8.9 ± 0.5, 5.3 ± 1.0, and 7.3 ± 0.5 and the VHNs were 19.4 ± 1.1, 21.1 ± 0.9, and 29.3 ± 0.6 for Groups 1L, 2L, and 3L, respectively. Therefore, to match the designated tooth color of resin inlays and to increase the early microhardness of DCRC, layered resin inlays are more appropriate than single-dentin-layer resin inlays. However, the translucent layer should be used cautiously because the color difference of resin inlays with a translucent layer was affected more than those without a translucent layer.

  5. Optimum concrete compression strength using bio-enzyme

    OpenAIRE

    Bagio Tony Hartono; Basoeki Makno; Tistogondo Julistyana; Pradana Sofyan Ali

    2017-01-01

    To make concrete with high compressive strength and has a certain concrete specifications other than the main concrete materials are also needed concrete mix quality control and other added material is also in line with the current technology of concrete mix that produces concrete with specific characteristics. Addition of bio enzyme on five concrete mixture that will be compared with normal concrete in order to know the optimum level bio-enzyme in concrete to increase the strength of the con...

  6. I-line stepper based overlay evaluation method for wafer bonding applications

    Science.gov (United States)

    Kulse, P.; Sasai, K.; Schulz, K.; Wietstruck, M.

    2018-03-01

    In the last decades the semiconductor technology has been driven by Moore's law leading to high performance CMOS technologies with feature sizes of less than 10 nm [1]. It has been pointed out that not only scaling but also the integration of novel components and technology modules into CMOS/BiCMOS technologies is becoming more attractive to realize smart and miniaturized systems [2]. Driven by new applications in the area of communication, health and automation, new components and technology modules such as BiCMOS embedded RF-MEMS, high-Q passives, Sibased microfluidics and InP-SiGe BiCMOS heterointegration have been demonstrated [3-6]. In contrast to standard VLSI processes fabricated on front side of the silicon wafer, these new technology modules additionally require to process the backside of the wafer; thus require an accurate alignment between the front and backside of the wafer. In previous work an advanced back to front side alignment technique and implementation into IHP's 0.25/0.13 µm high performance SiGe:C BiCMOS backside process module has been presented [7]. The developed technique enables a high resolution and accurate lithography on the backside of BiCMOS wafer for additional backside processing. In addition to the aforementioned back side process technologies, new applications like Through-Silicon Vias (TSV) for interposers and advanced substrate technologies for 3D heterogeneous integration demand not only single wafer fabrication but also processing of wafer stacks provided by temporary and permanent wafer bonding [8-9]. In this work, the non-contact infrared alignment system of the Nikon® i-line Stepper NSR-SF150 for both alignment and the overlay determination of bonded wafer stacks with embedded alignment marks are used to achieve an accurate alignment between the different wafer sides. The embedded field image alignment (FIA) marks of the interface and the device wafer top layer are measured in a single measurement job. By taking the

  7. Influence of bitumen type on cracking resistance of asphalt mixtures used in pavement overlays

    Science.gov (United States)

    Jaskula, P.; Szydlowski, C.; Stienss, M.

    2018-05-01

    Cracking is one of the predominant distresses occurring in flexible pavements, especially in old pavements that were rehabilitated with an asphalt overlay. In such cases asphalt mixtures should be designed to ensure high resistance to reflective cracking because new asphalt layers are exposed to existing cracks of the old pavement. The nature of these cracks can be various (transverse, longitudinal as well as crazy cracking). One factor that minimizes this type of distress is the proper mix design process, which should involve selection of specific bitumen binder and mineral mix gradation. However, still there is no universally adopted laboratory test method that would allow to clearly assess resistance of asphalt mixtures to reflective cracking. This paper describes the usage of one of the devices developed to test asphalt mixtures in terms of such distress – Texas Overlay Tester. For this test, samples prepared in laboratory conditions (i.e. compacted with the use of Superpave Gyratory Compactor) as well as obtained in the field (by core drilling) can be used. The results are obtained not only quickly and easily, but also with sufficient repeatability. The described method characterizes both crack initiation and crack propagation properties of asphalt mixtures. In this work one type of mineral mixture was tested with 4 different types of bitumen (one neat bitumen, two ordinary polymer-modified and one polymer-modified with high polymer content). For selected cases extra additives (rubber and loose fibres) were also tested. In total, six asphalt mixtures were tested. A ranking of the used binders was created on the basis of the results in order to conclude which bitumen would ensure the best performance characteristics in terms of reflective cracking. The results have clearly shown that deliberate choice of the binder used in the asphalt mixture for the overlay will significantly improve its reflective cracking resistance or even fatigue resistance.

  8. Passivating surface states on water splitting hematite photoanodes with alumina overlayers

    KAUST Repository

    Le Formal, Florian; Té treault, Nicolas; Cornuz, Maurin; Moehl, Thomas; Grä tzel, Michael; Sivula, Kevin

    2011-01-01

    Hematite is a promising material for inexpensive solar energy conversion via water splitting but has been limited by the large overpotential (0.5-0.6 V) that must be applied to afford high water oxidation photocurrent. This has conventionally been addressed by coating it with a catalyst to increase the kinetics of the oxygen evolution reaction. However, surface recombination at trapping states is also thought to be an important factor for the overpotential, and herein we investigate a strategy to passivate trapping states using conformal overlayers applied by atomic layer deposition. While TiO2 overlayers show no beneficial effect, we find that an ultra-thin coating of Al2O3 reduces the overpotential required with state-of-the-art nano-structured photo-anodes by as much as 100 mV and increases the photocurrent by a factor of 3.5 (from 0.24 mA cm-2 to 0.85 mA cm-2) at +1.0 V vs. the reversible hydrogen electrode (RHE) under standard illumination conditions. The subsequent addition of Co2+ ions as a catalyst further decreases the overpotential and leads to a record photocurrent density at 0.9 V vs. RHE (0.42 mA cm-2). A detailed investigation into the effect of the Al2O3 overlayer by electrochemical impedance and photoluminescence spectroscopy reveals a significant change in the surface capacitance and radiative recombination, respectively, which distinguishes the observed overpotential reduction from a catalytic effect and confirms the passivation of surface states. Importantly, this work clearly demonstrates that two distinct loss processes are occurring on the surface of high-performance hematite and suggests a viable route to individually address them. © The Royal Society of Chemistry 2011.

  9. Passivating surface states on water splitting hematite photoanodes with alumina overlayers

    KAUST Repository

    Le Formal, Florian

    2011-01-24

    Hematite is a promising material for inexpensive solar energy conversion via water splitting but has been limited by the large overpotential (0.5-0.6 V) that must be applied to afford high water oxidation photocurrent. This has conventionally been addressed by coating it with a catalyst to increase the kinetics of the oxygen evolution reaction. However, surface recombination at trapping states is also thought to be an important factor for the overpotential, and herein we investigate a strategy to passivate trapping states using conformal overlayers applied by atomic layer deposition. While TiO2 overlayers show no beneficial effect, we find that an ultra-thin coating of Al2O3 reduces the overpotential required with state-of-the-art nano-structured photo-anodes by as much as 100 mV and increases the photocurrent by a factor of 3.5 (from 0.24 mA cm-2 to 0.85 mA cm-2) at +1.0 V vs. the reversible hydrogen electrode (RHE) under standard illumination conditions. The subsequent addition of Co2+ ions as a catalyst further decreases the overpotential and leads to a record photocurrent density at 0.9 V vs. RHE (0.42 mA cm-2). A detailed investigation into the effect of the Al2O3 overlayer by electrochemical impedance and photoluminescence spectroscopy reveals a significant change in the surface capacitance and radiative recombination, respectively, which distinguishes the observed overpotential reduction from a catalytic effect and confirms the passivation of surface states. Importantly, this work clearly demonstrates that two distinct loss processes are occurring on the surface of high-performance hematite and suggests a viable route to individually address them. © The Royal Society of Chemistry 2011.

  10. MeshTree: A Delay optimised Overlay Multicast Tree Building Protocol

    OpenAIRE

    Tan, Su-Wei; Waters, A. Gill; Crawford, John

    2005-01-01

    We study decentralised low delay degree-constrained overlay multicast tree construction for single source real-time applications. This optimisation problem is NP-hard even if computed centrally. We identify two problems in traditional distributed solutions, namely the greedy problem and delay-cost trade-off. By offering solutions to these problems, we propose a new self-organising distributed tree building protocol called MeshTree. The main idea is to embed the delivery tree in a degree-bound...

  11. A theoretical study of symmetry-breaking organic overlayers on single- and bi-layer graphene

    Science.gov (United States)

    Morales-Cifuentes, Josue; Einstein, T. L.

    2013-03-01

    An ``overlayer'' of molecules that breaks the AB symmetry of graphene can produce (modify) a band gap in single- (bi-) layer graphene.[2] Since the triangular shaped trimesic acid (TMA) molecule forms two familiar symmetry breaking configurations, we are motivated to model TMA physisorption on graphene surfaces in conjunction with experiments by Groce et al. at UMD. Using VASP, with ab initio van der Waals density functionals (vdW-DF), we simulate adsorption of TMA onto a graphene surface in several symmetry-breaking arrangements in order to predict/understand the effect of TMA adsorption on experimental observables. Supported by NSF-MRSEC Grant DMR 05-20471.

  12. Critical temperatures of random iron–cobalt overlayers on the fcc-Cu(001) substrate

    Czech Academy of Sciences Publication Activity Database

    Mašín, Martin; Bergqvist, L.; Kudrnovský, Josef; Kotrla, Miroslav; Drchal, Václav

    2013-01-01

    Roč. 26, č. 4 (2013), s. 809-812 ISSN 1557-1939. [International Conference on Superconductivity and Magnetism (ICSM) /3./. Istanbul, 29.04.2012-04.05.2012] R&D Projects: GA ČR GA202/09/0775 Institutional support: RVO:68378271 Keywords : Curie temperature * random overlayer * Heisenberg Hamiltonian * first principles * Monte Carlo simulations Subject RIV: BE - Theoretical Physics Impact factor: 0.930, year: 2013 http://link.springer.com/article/10.1007/s10948-012-2084-1

  13. Electronic and structural characterizations of unreconstructed {0001} surfaces and the growth of graphene overlayers

    International Nuclear Information System (INIS)

    Emtsev, Konstantin

    2009-01-01

    The present work is focused on the characterization of the clean unreconstructed SiC{0001} surfaces and the growth of graphene overlayers thereon. Electronic properties of SiC surfaces and their interfaces with graphene and few layer graphene films were investigated by means of angle resolved photoelectron spectroscopy, X-ray photoelectron spectroscopy and low energy electron diffraction. Structural characterizations of the epitaxial graphene films grown on SiC were carried out by atomic force microscopy and low energy electron microscopy. Supplementary data was obtained by scanning tunneling microscopy. (orig.)

  14. VUV light induced valence degeneration in Sm over-layer on HOPG

    International Nuclear Information System (INIS)

    Kutluk, G; Nakatake, M; Arita, M; Namatame, H; Taniguchi, M; Ishitobi, Y; Sumida, H

    2013-01-01

    Systematic investigation of the influence of vacuum ultraviolet (VUV) irradiation on the valence degeneration in a Sm over-layer on a HOPG substrate was performed using in-situ photoemission spectroscopy (XPS, UPS, and ARPES) for the Sm coverage regime of 0.05-3.6 Å. This investigation confirmed that VUV irradiation-induced degeneration of divalent Sm exerts a more profound effect than Sm contamination during photoemission spectroscopy even under UHV. We found that the charge transfer occurs mainly from divalent Sm to the HOPG surface.

  15. Overlayer structure of subphthalocyanine derivative deposited on Au (111) surface by a spray-jet technique

    International Nuclear Information System (INIS)

    Suzuki, Hitoshi; Yamada, Toshiki; Miki, Hideki; Mashiko, Shinro

    2006-01-01

    A new spray-jet technique was used to deposit subphthalocyanine derivative (chloro[tri-tert-butyl subphthalocyaninato]boron (TBSubPc)) on Au (111) surface in an ultra-high vacuum (UHV) chamber. The deposited molecular overlayer was observed with UHV scanning tunneling microscopy (STM) at 77 K. The STM images showed that TBSubPc molecules formed a stripe pattern with regular spacing, indicating that they preferentially adsorbed along the herringbone structure of the Au (111) surface. This behavior was very similar to that of TBSubPc molecules deposited by thermal evaporation

  16. Use of Hydrogen Chemisorption and Ethylene Hydrogenation as Predictors for Aqueous Phase Reforming of Lactose over Ni@Pt and Co@Pt Bimetallic Overlayer Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Qinghua; Skoglund, Michael D.; Zhang, Chen; Morris, Allen R.; Holles, Joseph H.

    2016-10-20

    Overlayer Pt on Ni (Ni@Pt) or Co (Co@Pt) were synthesized and tested for H2 generation from APR of lactose. H2 chemisorption descriptor showed that Ni@Pt and Co@Pt overlayer catalysts had reduced H2 adsorption strength compared to a Pt only catalyst, which agree with computational predictions. The overlayer catalysts also demonstrated lower activity for ethylene hydrogenation than the Pt only catalyst, which likely resulted from decreased H2 binding strength decreasing the surface coverage of H2. XAS results showed that overlayer catalysts exhibited higher white line intensity than the Pt catalyst, which indicates a negative d-band shift for the Pt overlayer, further providing evidence for overlayer formation. Lactose APR studies showed that lactose can be used as feedstock to produce H2 and CO under desirable reaction conditions. The Pt active sites of Ni@Pt and Co@Pt overlayer catalysts showed significantly enhanced H2 production selectivity and activity when compared with that of a Pt only catalyst. The single deposition overlayer with the largest d-band shift showed the highest H2 activity. The results suggest that overlayer formation using directed deposition technique could modify the behavior of the surface metal and ultimately modify the APR activity.

  17. Prediction of concrete strength in massive structures

    International Nuclear Information System (INIS)

    Sakamoto, T.; Makino, H.; Nakane, S.; Kawaguchi, T.; Ohike, T.

    1989-01-01

    Reinforced concrete structures of a nuclear power plant are mostly of mass concrete with cross-sectional dimensions larger than 1.0 m. The temperature of concrete inside after placement rises due to heat of hydration of cement. It is well known that concrete strengths of mass concrete structure subjected to such temperature hysteresis are generally not equal to strengths of cylinders subjected to standard curing. In order to construct a mass concrete structure of high reliability in which the specified concrete strength is satisfied by the specified age, it is necessary to have a thorough understanding of the strength gain property of concrete in the structure and its relationships with the water-cement ratio of the mix, strength of standard-cured cylinders and the internal temperature hysteresis. This report describes the result of studies on methods of controlling concrete strength in actual construction projects

  18. Modeling and simulation of adaptive Neuro-fuzzy based intelligent system for predictive stabilization in structured overlay networks

    Directory of Open Access Journals (Sweden)

    Ramanpreet Kaur

    2017-02-01

    Full Text Available Intelligent prediction of neighboring node (k well defined neighbors as specified by the dht protocol dynamism is helpful to improve the resilience and can reduce the overhead associated with topology maintenance of structured overlay networks. The dynamic behavior of overlay nodes depends on many factors such as underlying user’s online behavior, geographical position, time of the day, day of the week etc. as reported in many applications. We can exploit these characteristics for efficient maintenance of structured overlay networks by implementing an intelligent predictive framework for setting stabilization parameters appropriately. Considering the fact that human driven behavior usually goes beyond intermittent availability patterns, we use a hybrid Neuro-fuzzy based predictor to enhance the accuracy of the predictions. In this paper, we discuss our predictive stabilization approach, implement Neuro-fuzzy based prediction in MATLAB simulation and apply this predictive stabilization model in a chord based overlay network using OverSim as a simulation tool. The MATLAB simulation results present that the behavior of neighboring nodes is predictable to a large extent as indicated by the very small RMSE. The OverSim based simulation results also observe significant improvements in the performance of chord based overlay network in terms of lookup success ratio, lookup hop count and maintenance overhead as compared to periodic stabilization approach.

  19. Friction and wear of stainless steel, titanium and aluminium with various surface treatments, ion implantation and overlay hard coatings

    International Nuclear Information System (INIS)

    Bunshah, R.F.

    1979-01-01

    This paper deals with the evaluation of the wear properties of 304 stainless steel, commercial grade titanium and commercial grade aluminium without and with different surface treatments, i.e., ion implantation of boron and nitrogen, and overlay coating of superhard materials, titanium carbide and nitride by the Biased Activated Reactive Evaporation (BARE) process. Wear properties were evaluated in adhesive, erosive and abrasive modes of wear. In the case of adhesive wear, ion implantation resulted in an improved wear behaviour in lubricated conditions but had no beneficial effect in dry wear conditions. Overlay coatings on the other hand resulted in improved wear behaviour for both the dry and lubricating conditions. In the case of erosive wear with SiC particles at high velocities, overlay coatings showed higher erosion rates (typical of brittle materials in normal impingement) whereas ion implanted materials behaved similarly as untreated materials; i.e., a lower wear rate than the specimens with overlay coatings. In the case of abrasive wear, it was again observed that the wear rates of overlay coatings is far lower than the wear rates of untreated or ion implanted materials. (author)

  20. Reducing overlay sampling for APC-based correction per exposure by replacing measured data with computational prediction

    Science.gov (United States)

    Noyes, Ben F.; Mokaberi, Babak; Oh, Jong Hun; Kim, Hyun Sik; Sung, Jun Ha; Kea, Marc

    2016-03-01

    One of the keys to successful mass production of sub-20nm nodes in the semiconductor industry is the development of an overlay correction strategy that can meet specifications, reduce the number of layers that require dedicated chuck overlay, and minimize measurement time. Three important aspects of this strategy are: correction per exposure (CPE), integrated metrology (IM), and the prioritization of automated correction over manual subrecipes. The first and third aspects are accomplished through an APC system that uses measurements from production lots to generate CPE corrections that are dynamically applied to future lots. The drawback of this method is that production overlay sampling must be extremely high in order to provide the system with enough data to generate CPE. That drawback makes IM particularly difficult because of the throughput impact that can be created on expensive bottleneck photolithography process tools. The goal is to realize the cycle time and feedback benefits of IM coupled with the enhanced overlay correction capability of automated CPE without impacting process tool throughput. This paper will discuss the development of a system that sends measured data with reduced sampling via an optimized layout to the exposure tool's computational modelling platform to predict and create "upsampled" overlay data in a customizable output layout that is compatible with the fab user CPE APC system. The result is dynamic CPE without the burden of extensive measurement time, which leads to increased utilization of IM.

  1. Use of rubber crumbs in cement concrete

    Science.gov (United States)

    Longvinenko, A. A.

    2018-03-01

    Rubber crumb obtained from worn out tires has been increasingly used over the last 15-20 years, especially in manufacture of asphalt and cement concrete mixtures. This review pays principal attention to application of the rubber crumb to cement concrete mixtures. Use of the rubber crumb in cement concrete is not as successful as in asphalt concrete mixtures, due to incompatibility problems linked to chemical composition and a significant difference in rigidity between the rubber crumb and concrete mixture aggregates. Different methods are proposed and studied to mitigate the adverse influence and increase the beneficial effects of the rubber crumb when added to cement concrete.

  2. A study on sodium-concrete reaction

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Jae Heum; Min, Byong Hun [Suwon University, Suwon (Korea, Republic of)

    1997-07-01

    A small sodium-concrete reaction facility was designed, manufactured and installed. this facility has been operated under inert gas(N{sub 2}) with different experimental variables such as sodium injection temperature, injection amount of sodium, aging period of concrete, sodium reservoir temperature. As a result, it was found that sodium injection temperature and injected amount of sodium has little effect on sodium-concrete reaction. However, sodium reservoir temperature and aging period of concrete has relatively high impact on sodium-concrete reaction. Sodium-concrete reaction model has also been developed and compared with experimental results. (Author) 51 refs., 16 tabs., 64 figs.

  3. Large Scale Glazed Concrete Panels

    DEFF Research Database (Denmark)

    Bache, Anja Margrethe

    2010-01-01

    Today, there is a lot of focus on concrete surface’s aesthitic potential, both globally and locally. World famous architects such as Herzog De Meuron, Zaha Hadid, Richard Meyer and David Chippenfield challenge the exposure of concrete in their architecture. At home, this trend can be seen...... in the crinkly façade of DR-Byen (the domicile of the Danish Broadcasting Company) by architect Jean Nouvel and Zaha Hadid’s Ordrupgård’s black curved smooth concrete surfaces. Furthermore, one can point to initiatives such as “Synlig beton” (visible concrete) that can be seen on the website www.......synligbeton.dk and spæncom’s aesthetic relief effects by the designer Line Kramhøft (www.spaencom.com). It is my hope that the research-development project “Lasting large scale glazed concrete formwork,” I am working on at DTU, department of Architectural Engineering will be able to complement these. It is a project where I...

  4. 304 Concretion facility closure plan

    International Nuclear Information System (INIS)

    1990-04-01

    The Hanford Site, located northwest of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials. The 300 Area of the Hanford Site contains reactor fuel manufacturing facilities and several research and development laboratories. Recyclable scrap uranium Zircaloy-2 and copper silicon alloy, uranium-titanium alloy, beryllium/Zircaloy-2 alloy, and Zircaloy-2 chips and fines were secured in concrete billets in the 304 Concretion Facility, located in the 300 Area. The beryllium/Zircaloy-2 alloy and Zircaloy-2 chips and fines are designated as low-level radioactive mixed waste (LLRMW) with the characteristic of ignitability. The concretion process reduced the ignitability of the fines and chips for safe storage and shipment. This process has been discontinued and the 304 Concretion Facility is now undergoing closure as defined in the Resource Conservation and Recovery Act of 1976 (RCRA). This closure plan presents a description of the facility, the history of materials and wastes managed, and the procedures that will be followed to close the 304 Concretion Facility (304 Facility). Clean closure of the 304 Facility is the proposed method for closure of the facility. Justification for this proposal is presented. 15 refs., 22 figs., 4 tabs

  5. The Tectonic Potentials of Concrete

    DEFF Research Database (Denmark)

    Egholm Pedersen, Ole

    2013-01-01

    Contemporary techniques for concrete casting in an architectural context are challenged by demands of increased individualization in our built environment, reductions in the use of resources and waste generation. In recent years, new production technologies and strategies that break with the indu......Contemporary techniques for concrete casting in an architectural context are challenged by demands of increased individualization in our built environment, reductions in the use of resources and waste generation. In recent years, new production technologies and strategies that break...... with the industrial paradigm of standardization, have been put forward. This development is carried forward by computers and digital fabrication, but has yet to find its way into the production of building components. With regards to concrete casting, however, existing research do offer advancement towards...... an increased customisation of casting moulds. The hypothesis of this research is that the techniques used in this research do not fully address the tectonic potentials of concrete which gives rise to the primary research question: Is it possible to enhance existing or develop new concrete casting techniques...

  6. Nanogranular origin of concrete creep.

    Science.gov (United States)

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-06-30

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium-silicate-hydrates (C-S-H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C-S-H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C-S-H forms: low density, high density, ultra-high density. We demonstrate that the creep rate ( approximately 1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years.

  7. Optimización multiobjetivo para enrutamiento multicast en overlay networks utilizando algoritmos evolutivos Multiobjective Optimization for Multicast Routing in Overlay Networks using Evolutionary Algorithms

    Directory of Open Access Journals (Sweden)

    Juan Carlos Montoya M.

    2008-06-01

    Full Text Available Multicast juega un papel muy importante para soportar una nueva generación de aplicaciones. En la actualidad y por diferentes razones, técnicas y no técnicas, multicast IP no ha sido totalmente adoptado en Internet. Durante los últimos a˜nos, un área de investigación activa es la de implementar este tipo de tráfico desde la perspectiva del nivel de aplicación, donde la funcionalidad de multicast no es responsabilidad de los enrutadores sino de los hosts, a lo que se le conoce como Multicast Overlay Network (MON. En este artículo se plantea el enrutamiento en MON como un problema de Optimización Multiobjetivo (MOP donde se optimizan dos funciones: 1 el retardo total extremo a extremo del árbol multicast, y 2 la máxima utilización de los enlaces. La optimización simultánea de estas dos funciones es un problema NP completo y para resolverlo se propone utilizar Algoritmos Evolutivos Multiobjetivos (MOEA, específicamente NSGAIMulticast plays an important role in supporting a new generation of applications. At present and for different reasons, technical and non–technical, multicast IP hasn’t yet been totally adopted for Internet. During recent years, an active area of research is that of implementing this kind of traffic in the application layer where the multicast functionality isn´t a responsibility of the routers but that of the hosts, which we know as Multicast Overlay Networks (MON. In this article, routing in an MON is put forward as a multiobjective optimization problem (MOP where two functions are optimized: 1 the total end to end delay of the multicast tree and 2 the maximum link utilization. The simultaneous optimization of these two functions is an NP–Complete problem and to solve this we suggest using Multiobjective Evolutionary Algorithms (MOEA, specifically NSGA–II.

  8. Effect of preemptive weld overlay on residual stress mitigation for dissimilar metal weld of nuclear power plant pressurizer

    International Nuclear Information System (INIS)

    Song, Tae Kwang; Bae, Hong Yeol; Chun, Yun Bae; Oh, Chang Young; Kim, Yun Jae; Lee, Kyoung Soo; Park, Chi Yong

    2008-01-01

    Weld overlay is one of the residual stress mitigation methods which arrest crack initiation and crack growth. Therefore weld overlay can be applied to the region where cracking is likely to be. An overlay weld used in this manner is termed a Preemptive Weld OverLay(PWOL). In Pressurized Water Reactor(PWR) dissimilar metal weld is susceptible region for Primary Water Stress Corrosion Cracking(PWSCC). In order to examine the effect of PWOL on residual stress mitigation, PWOL was applied to a specific dissimilar metal weld of Kori nuclear power plant by finite element analysis method. As a result, strong compressive residual stress was made in PWSCC susceptible region and PWOL was proved effective preemptive repair method for weldment

  9. Effect of preemptive weld overlay on residual stress mitigation for dissimilar metal weld of nuclear power plant pressurizer

    Energy Technology Data Exchange (ETDEWEB)

    Song, Tae Kwang; Bae, Hong Yeol; Chun, Yun Bae; Oh, Chang Young; Kim, Yun Jae [Korea University, Seoul (Korea, Republic of); Lee, Kyoung Soo; Park, Chi Yong [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

    2008-10-15

    Weld overlay is one of the residual stress mitigation methods which arrest crack initiation and crack growth. Therefore weld overlay can be applied to the region where cracking is likely to be. An overlay weld used in this manner is termed a Preemptive Weld OverLay(PWOL). In Pressurized Water Reactor(PWR) dissimilar metal weld is susceptible region for Primary Water Stress Corrosion Cracking(PWSCC). In order to examine the effect of PWOL on residual stress mitigation, PWOL was applied to a specific dissimilar metal weld of Kori nuclear power plant by finite element analysis method. As a result, strong compressive residual stress was made in PWSCC susceptible region and PWOL was proved effective preemptive repair method for weldment.

  10. Evaluating the mechanical performance of Very Thin Asphalt Overlay (VTAO as a sustainable rehabilitation strategy in urban pavements

    Directory of Open Access Journals (Sweden)

    M. Sol-Sánchez

    2017-07-01

    Full Text Available Very Thin Asphalt Overlay (VTAO has been introduced as an alternative to traditional thick overlays, seal coats, and micro-surfacings. Nonetheless, there are some challenges that still remain regarding the application of VTAOs (such as mixture type, cohesiveness, wear resistance, cracking and durability, particularly in heavy traffic urban areas. Therefore, this paper presents an extensive comparative evaluation of the mechanical performance, durability and safety issues (cohesiveness, adhesiveness, ageing, cracking, plastic deformation, permeability, macrotexture, skid and wear resistance, and fuel resistance of a VTAO (20 mm thick and a high performance BBTM 11B (35 mm thick, commonly used as an open-graded mixture for pavement overlays. The results demonstrated that VTAO is an appropriate material for urban pavements as it provides good durability and resistance to the propagation of defects. Nonetheless, further studies are required to improve its behavior under distresses related to plastic deformations and safety properties.

  11. Evaluating the mechanical performance of Very Thin Asphalt Overlay (VTAO) as a sustainable rehabilitation strategy in urban pavements

    International Nuclear Information System (INIS)

    Sol-Sánchez, M.; García-Travé, G.; Ayar, P.; Moreno-Navarro, F.; Rubio-Gámez, M.C.

    2017-01-01

    Very Thin Asphalt Overlay (VTAO) has been introduced as an alternative to traditional thick overlays, seal coats, and micro-surfacings. Nonetheless, there are some challenges that still remain regarding the application of VTAOs (such as mixture type, cohesiveness, wear resistance, cracking and durability), particularly in heavy traffic urban areas. Therefore, this paper presents an extensive comparative evaluation of the mechanical performance, durability and safety issues (cohesiveness, adhesiveness, ageing, cracking, plastic deformation, permeability, macrotexture, skid and wear resistance, and fuel resistance) of a VTAO (20 mm thick) and a high performance BBTM 11B (35 mm thick), commonly used as an open-graded mixture for pavement overlays. The results demonstrated that VTAO is an appropriate material for urban pavements as it provides good durability and resistance to the propagation of defects. Nonetheless, further studies are required to improve its behavior under distresses related to plastic deformations and safety properties. [es

  12. Characterization of the Interface of an Alloy 625 Overlay on Steels Using Nanoindentation

    Science.gov (United States)

    Dai, Tao; Lippold, John

    2018-06-01

    Industry standards require postweld heat treatment (PWHT) to reduce the heat-affected zone hardness of steels such as F22 (2.25Cr-1Mo) and AISI 8630 overlaid (clad) with Alloy 625 weld metal. PWHT results in carbon diffusion and accumulation at the interface between the steel and overlay. The accumulation of carbon in a planar solidification growth zone adjacent to the fusion boundary results in high hardness and the potential for hydrogen-assisted cracking. The planar growth zone (PGZ) is so narrow that normal Vickers hardness testing cannot fully reveal the hardness distribution in this zone. This study focused on the application of nanoindentation to characterize the hardness in the narrow microstructural regions adjacent to the fusion boundary. The development of nanohardness maps revealed that the PGZ is not necessarily the region that exhibits peak hardness after PWHT. The highest hardness values were associated with clusters of M7C3 carbides in specific subregions in the PGZ and also in the partially-mixed zone adjacent to the fusion boundary or in steel "swirl" structures. It was also confirmed in this study that nanohardness has a linear correlation with Vickers hardness values. The results presented here provide new insight into the role of carbon diffusion during PWHT and its effect on interface embrittlement associated with Alloy 625 overlays on steel.

  13. Vision-based overlay of a virtual object into real scene for designing room interior

    Science.gov (United States)

    Harasaki, Shunsuke; Saito, Hideo

    2001-10-01

    In this paper, we introduce a geometric registration method for augmented reality (AR) and an application system, interior simulator, in which a virtual (CG) object can be overlaid into a real world space. Interior simulator is developed as an example of an AR application of the proposed method. Using interior simulator, users can visually simulate the location of virtual furniture and articles in the living room so that they can easily design the living room interior without placing real furniture and articles, by viewing from many different locations and orientations in real-time. In our system, two base images of a real world space are captured from two different views for defining a projective coordinate of object 3D space. Then each projective view of a virtual object in the base images are registered interactively. After such coordinate determination, an image sequence of a real world space is captured by hand-held camera with tracking non-metric measured feature points for overlaying a virtual object. Virtual objects can be overlaid onto the image sequence by taking each relationship between the images. With the proposed system, 3D position tracking device, such as magnetic trackers, are not required for the overlay of virtual objects. Experimental results demonstrate that 3D virtual furniture can be overlaid into an image sequence of the scene of a living room nearly at video rate (20 frames per second).

  14. Potential of zero free charge of Pd overlayers on Pt(1 1 1)

    International Nuclear Information System (INIS)

    El-Aziz, A.M.; Hoyer, R.; Kibler, L.A.; Kolb, D.M.

    2006-01-01

    Differential capacitance measurements of Pd overlayers on a Pt(1 1 1) electrode in dilute aqueous NaF solutions have been performed as a function of film thickness in order to determine the potential of zero free charge (pzfc). The pzfc of the first, pseudomorphic Pd monolayer on Pt(1 1 1) is -0.21 V versus SCE. By increasing the amount of deposited Pd, a clear shift of the pzfc to more positive values is observed. After deposition of an equivalent of 10 monolayers, the value approaches that of a massive Pd(1 1 1) electrode (-0.12 V versus SCE). The pzfc's for the various Pd coverages are correlated with surface structure information, derived from STM images (R. Hoyer, L.A. Kibler, D.M. Kolb, Electrochim. Acta 49 (2003) 63). Variations in the pzfc are discussed in the context of an electronic modification by the underlying substrate and are compared with corresponding data for Pd overlayers on Au(1 1 1)

  15. Improving Management Performance of P2PSIP for Mobile Sensing in Wireless Overlays

    Directory of Open Access Journals (Sweden)

    José María Pousada-Carballo

    2013-11-01

    Full Text Available Future wireless communications are heading towards an all-Internet Protocol (all-IP design, and will rely on the Session Initiation Protocol (SIP to manage services, such as voice over IP (VoIP. The centralized architecture of traditional SIP has numerous disadvantages for mobile ad hoc services that may be possibly overcome by advanced peer-to-peer (P2P technologies initially developed for the Internet. In the context of mobile sensing, P2PSIP protocols facilitate decentralized and fast communications with sensor-enabled terminals. Nevertheless, in order to make P2PSIP protocols feasible in mobile sensing networks, it is necessary to minimize overhead transmissions for signaling purposes, which reduces the battery lifetime. In this paper, we present a solution to improve the management of wireless overlay networks by defining an adaptive algorithm for the calculation of refresh time. The main advantage of the proposed algorithm is that it takes into account new parameters, such as the delay between nodes, and provides satisfactory performance and reliability levels at a much lower management overhead than previous approaches. The proposed solution can be applied to many structured P2P overlays or P2PSIP protocols. We evaluate it with Kademlia-based distributed hash tables (DHT and dSIP.

  16. Improving management performance of P2PSIP for mobile sensing in wireless overlays.

    Science.gov (United States)

    Sendín-Raña, Pablo; González-Castaño, Francisco Javier; Gómez-Cuba, Felipe; Asorey-Cacheda, Rafael; Pousada-Carballo, José María

    2013-11-08

    Future wireless communications are heading towards an all-Internet Protocol (all-IP) design, and will rely on the Session Initiation Protocol (SIP) to manage services, such as voice over IP (VoIP). The centralized architecture of traditional SIP has numerous disadvantages for mobile ad hoc services that may be possibly overcome by advanced peer-to-peer (P2P) technologies initially developed for the Internet. In the context of mobile sensing, P2PSIP protocols facilitate decentralized and fast communications with sensor-enabled terminals. Nevertheless, in order to make P2PSIP protocols feasible in mobile sensing networks, it is necessary to minimize overhead transmissions for signaling purposes, which reduces the battery lifetime. In this paper, we present a solution to improve the management of wireless overlay networks by defining an adaptive algorithm for the calculation of refresh time. The main advantage of the proposed algorithm is that it takes into account new parameters, such as the delay between nodes, and provides satisfactory performance and reliability levels at a much lower management overhead than previous approaches. The proposed solution can be applied to many structured P2P overlays or P2PSIP protocols. We evaluate it with Kademlia-based distributed hash tables (DHT) and dSIP.

  17. Elastic helium scattering studies of ordered overlayers of Ar, Kr, and Xe physisorbed on Ag(111)

    International Nuclear Information System (INIS)

    Gibson, K.D.; Cerjan, C.; Light, J.C.; Sibener, S.J.

    1988-01-01

    We describe experiments that measured the angle resolved intensity of He (E/sub i/ = 18 and 66 meV) elastically scattering from the surfaces of rare gas overlayers physisorbed on Ag(111). These studies were done on a layer-by-layer basis for 1, 2, 3, and ∼25 ordered overlayers of Ar, Kr, and Xe. Two types of experiments are described. The first is diffraction, where the scattered He intensity was measured as a function of the detector angle, with the incident polar and azimuthal angles held constant. In the second type of experiment, selective adsorption, we measured the specular intensity as a function of incident angle. The purpose of these experiments was to examine the He--surface potential, to assess the relative contributions that various He--rare gas pair potentials, nonadditive multibody terms, and He--substrate interactions make to the systems studied. The experiments are compared with the results of accurate close-coupling calculations, in order to quantitatively perform these assessments. The comparisons between the selective adsorption data and scattering calculations demonstrate the extreme sensitivity that such measurements have to the He--surface potential. In particular, observable changes in the calculated selective adsorption spectra appear when different He--rare gas potentials are tested, or when various nonadditive terms are included in the potential. The results suggest that further refinements in the He-heavy--rare gas pair potentials may be in order

  18. The Effects of a Dynamic Spectrum Access Overlay in LTE-Advanced Networks

    Energy Technology Data Exchange (ETDEWEB)

    Juan D. Deaton; Ryan E. lrwin; Luiz A. DaSilva

    2011-05-01

    As early as 2014, wireless network operators spectral capacity will be overwhelmed by a data tsunami brought on by new devices and applications. To augment spectral capacity, operators could deploy a Dynamic Spectrum Access (DSA) overlay. In the light of the many planned Long Term Evolution (LTE) network deployments, the affects of a DSA overlay have not been fully considered into the existing LTE standards. Coalescing many different aspects of DSA, this paper develops the Spectrum Accountability (SA) framework. The SA framework defines specific network element functionality, protocol interfaces, and signaling flow diagrams for LTE to support service requests and enforce rights of responsibilities of primary and secondary users, respectively. We also include a network simulation to quantify the benefits of using DSA channels to augment capacity. Based on our simulation we show that, network operators can benefit up to %40 increase in operating capacity when sharing DSA bands to augment spectral capacity. With our framework, this paper could serve as an guide in developing future LTE network standards that include DSA.

  19. Single-Layer Limit of Metallic Indium Overlayers on Si(111).

    Science.gov (United States)

    Park, Jae Whan; Kang, Myung Ho

    2016-09-09

    Density-functional calculations are used to identify one-atom-thick metallic In phases grown on the Si(111) surface, which have long been sought in quest of the ultimate two-dimensional (2D) limit of metallic properties. We predict two metastable single-layer In phases, one sqrt[7]×sqrt[3] phase with a coverage of 1.4 monolayer (ML; here 1 ML refers to one In atom per top Si atom) and the other sqrt[7]×sqrt[7] phase with 1.43 ML, which indeed agree with experimental evidences. Both phases reveal quasi-1D arrangements of protruded In atoms, leading to 2D-metallic but anisotropic band structures and Fermi surfaces. This directional feature contrasts with the free-electron-like In-overlayer properties that are known to persist up to the double-layer thickness, implying that the ultimate 2D limit of In overlayers may have been achieved in previous studies of double-layer In phases.

  20. Spatial Analysis for Potential Water Catchment Areas using GIS: Weighted Overlay Technique

    Science.gov (United States)

    Awanda, Disyacitta; Anugrah Nurul, H.; Musfiroh, Zahrotul; Dinda Dwi, N. P.

    2017-12-01

    The development of applied GIS is growing rapidly and has been widely applied in various fields. Preparation of a model to obtain information is one of the benefits of GIS. Obtaining information for water resources such as water catchment areas is one part of GIS modelling. Water catchment model can be utilized to see the distribution of potential and ability of a region in water absorbing. The use of overlay techniques with the weighting obtained from the literature from previous research is used to build the model. Model builder parameters are obtained through remote sensing interpretation techniques such as land use, landforms, and soil texture. Secondary data such as rock type maps are also used as water catchment model parameters. The location of this research is in the upstream part of the Opak river basin. The purpose of this research is to get information about potential distribution of water catchment area with overlay technique. The results of this study indicate the potential of water catchment areas with excellent category, good, medium, poor and very poor. These results may indicate that the Upper river basin is either good or in bad condition, so it can be used for better water resources management policy determination.

  1. How a gold substrate can increase the reactivity of a Pt overlayer

    DEFF Research Database (Denmark)

    Pedersen, Morten Ø.; Helveg, Stig; Ruban, Andrei

    1999-01-01

    The growth and chemical reactivity of Pt on Au(111) have been studied using scanning tunneling microscopy (STM) and temperature programmed desorption (TPD). Deposition of Pt at coverages from 0.02 ML up to 2.5 ML on Au(111) at room temperature initially leads to the formation of a surface alloy......, in which 3% of the Au atoms are replaced by Pt. Subsequent Pt evaporation leads to island growth with a mixed Pt-Au island composition. The reactivity of the Pt/Au system is studied using CO as a probe molecule. We show that a stronger bonding of CO to the first layer of Pt on Au(111) exists compared...... with the binding of CO on clean Pt. The Au substrate therefore very surprisingly increases the Pt overlayer reactivity. The results can be understood in a simple model, in which the change in the CO binding energy is directly proportional to the shift of the d-band center of the metal overlayer. According...

  2. Determination of welding parameters for execution of weld overlayer on PWR nuclear reactor nozzles

    International Nuclear Information System (INIS)

    Ribeiro, Gabriela M.; Lima, Luciana I.; Quinan, Marco A.; Schvartzman, Monica M.

    2009-01-01

    In the PWR reactors, nickel based dissimilar welds have been presented susceptibilities the stress corrosion (S C). For the mitigation the problem a deposition of weld layers on the external surface of the nozzle is an alternative, viewing to provoke the compression of the region subjected to S C. This paper presents a preliminary study on the determination of welding parameters to obtain these welding overlayers. Welding depositions were performed on a test piece welded with nickel 182 alloy, simulating the conditions of a nozzle used in a PWR nuclear power plant. The welding process was the GTAW (Gas Tungsten Arc Welding), and a nickel 52 alloy as addition material. The overlayers were performed on the base metals, carbon steel an stainless steel, changing the welding parameters and verifying the the time of each weld filet. After that, the samples were micro structurally characterized. The macro structures and the microstructures obtained through optical microscopy and Vickers microhardness are presented. The preliminary results make evident the good weld quality. However, a small weld parameters influence used in the base material microstructure (carbon steel and stainless steel). The obtained results in this study will be used as reference in the construction of a mock up which will simulate all the conditions of a pressurizer nozzle of PWR reactor

  3. Bandwidth and power allocation for two-way relaying in overlay cognitive radio systems

    KAUST Repository

    Alsharoa, Ahmad M.

    2014-12-01

    In this paper, the problem of both bandwidth and power allocation for two-way multiple relay systems in overlay cognitive radio (CR) setup is investigated. In the CR overlay mode, primary users (PUs) cooperate with cognitive users (CUs) for mutual benefits. In our framework, we propose that the CUs are allowed to allocate a part of the PUs spectrum to perform their cognitive transmission. In return, acting as an amplify-and-forward two-way relays, they are used to support PUs to achieve their target data rates over the remaining bandwidth. More specifically, CUs acts as relays for the PUs and gain some spectrum as long as they respect a specific power budget and primary quality-of-service constraints. In this context, we first derive closed-form expressions for optimal transmit power allocated to PUs and CUs in order to maximize the cognitive objective. Then, we employ a strong optimization tool based on particle swarm optimization algorithm to find the optimal relay amplification gains and optimal cognitive released bandwidths as well. Our numerical results illustrate the performance of our proposed algorithm for different utility metrics and analyze the impact of some system parameters on the achieved performance.

  4. Oral rehabilitation of a patient with amelogenesis imperfecta using removable overlay denture: a clinical report.

    Science.gov (United States)

    Ghodsi, S; Rasaeipour, S; Vojdani, M

    2012-03-01

    The aim of this study was oral rehabilitation of 17-year old patient with amelogenesis imperfecta using removable overlay denture in order to satisfy her esthetic and functional expectations and enhance her self-image. Amelogenesis imperfecta (AI) is a group of genetic disorders that primarily affect the quality and quantity of amelogenesis in both primary and permanent dentitions. The main clinical characteristics are severe attrition, tooth sensitivity and unesthetic appearance. This clinical report illustrates the oral rehabilitation of a 17-year-old girl with hypoplastic-hypomature type of AI with cobalt-chromium (Co-Cr) overlay removable partial denture (ORPD) that is one of the most economical and biocompatible replacements for noble metal and nickel-chromium (Ni-Cr) alloy. The presented case report suggests that Co-Cr ORPD can be a good temporary or even permanent treatment option for AI patients with limited budget, low esthetic concerns or medical limitations. There are major advantages in cast metal ORPDs; they are simpler, less traumatic and less expensive than fixed prosthetic options. This case report supports their use in patients with amelogenesis imperfecta.

  5. An efficient mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks

    Science.gov (United States)

    Yu, Xiaojun; Xiao, Gaoxi; Cheng, Tee Hiang

    2014-08-01

    This paper proposes an efficient overlay multicast provisioning (OMP) mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks. To facilitate request provisioning, OMP jointly utilizes a data learning (DL) scheme on the IP/MPLS layer for logical link cost estimation, and a lightpath fragmentation (LPF) based method on the WDM layer for improving resource sharing in grooming process. Extensive simulations are carried out to evaluate the performance of OMP mechanism under different traffic loads, with either limited or unlimited port resources. Simulation results demonstrate that OMP significantly outperforms the existing methods. To evaluate the respective influences of the DL scheme and the LPF method on OMP performance, provisioning mechanisms only utilizing either the IP/MPLS layer DL scheme or the WDM layer LPF method are also devised. Comparison results show that both DL and LPF methods help improve OMP blocking performance, and contribution from the DL scheme is more significant when the fixed routing and first-fit wavelength assignment (RWA) strategy is adopted on the WDM layer. Effects of a few other factors, including definition of connection cost to be reported by the WDM layer to the IP/MPLS layer and WDM-layer routing method, on OMP performance are also evaluated.

  6. Sputtering of thin benzene and polystyrene overlayers by keV Ga and C60 bombardment

    International Nuclear Information System (INIS)

    Czerwinski, B.; Delcorte, A.; Garrison, B.J.; Samson, R.; Winograd, N.; Postawa, Z.

    2006-01-01

    The mechanisms of ion-stimulated desorption of thin organic overlayers deposited on metal substrates by mono- and polyatomic projectiles are examined using molecular dynamics (MD) computer simulations. A monolayer of polystyrene tetramers (PS4) physisorbed on Ag{1 1 1} is irradiated by 15 keV Ga and C 60 projectiles at normal incidence. The results are compared with the data obtained for a benzene overlayer to investigate the differences in sputtering mechanisms of weakly and strongly bound organic molecules. The results indicate that the sputtering yield decreases with the increase of the binding energy and the average kinetic energy of parent molecules is shifted toward higher kinetic energy. Although the total sputtering yield of organic material is larger for 15 keV C 60 , the impact of this projectile leads to a significant fragmentation of ejected species. As a result, the yield of the intact molecules is comparable for C 60 and Ga projectiles. Our data indicate that chemical analysis of the very thin organic films performed by detection of sputtered neutrals will not benefit from the use of C 60 projectiles

  7. Hot Corrosion of Inconel 625 Overlay Weld Cladding in Smelting Off-Gas Environment

    Science.gov (United States)

    Mohammadi Zahrani, E.; Alfantazi, A. M.

    2013-10-01

    Degradation mechanisms and hot corrosion behavior of weld overlay alloy 625 were studied. Phase structure, morphology, thermal behavior, and chemical composition of deposited salt mixture on the weld overlay were characterized utilizing XRD, SEM/EDX, DTA, and ICP/OES, respectively. Dilution level of Fe in the weldment, dendritic structure, and degradation mechanisms of the weld were investigated. A molten phase formed on the weld layer at the operating temperature range of the boiler, which led to the hot corrosion attack in the water wall and the ultimate failure. Open circuit potential and weight-loss measurements and potentiodynamic polarization were carried out to study the hot corrosion behavior of the weld in the simulated molten salt medium at 873 K, 973 K, and 1073 K (600 °C, 700 °C, and 800 °C). Internal oxidation and sulfidation plus pitting corrosion were identified as the main hot corrosion mechanisms in the weld and boiler tubes. The presence of a significant amount of Fe made the dendritic structure of the weld susceptible to preferential corrosion. Preferentially corroded (Mo, Nb)-depleted dendrite cores acted as potential sites for crack initiation from the surface layer. The penetration of the molten phase into the cracks accelerated the cracks' propagation mainly through the dendrite cores and further crack branching/widening.

  8. HYDRAULIC CONCRETE COMPOSITION AND PROPERTIES CONTROL SYSTEM

    Directory of Open Access Journals (Sweden)

    O. M. Pshinko

    2015-08-01

    Full Text Available Purpose. Scientific work aims at the development and testing of information system to meet the challenges of concrete composition design and control (for railway structures and buildings based on the physico-analytical method algorithm for hydraulic concrete composition calculation. Methodology. The proposed algorithm of hydraulic concrete composition calculation is based on the physicochemical mechanics and in particular on the rheology of elastic–viscous–plastic bodies. The system of canonical equations consists of the equations for concrete strength, absolute volume, concrete mix consistency as well as the equation for optimal concrete saturation with aggregates while minimizing cement content. The joint solution of these four equations related to composition allows determining for the materials the concrete composition of required strength, concrete workability with minimum cement content. The procedure for calculation of hydraulic concrete composition according to the physico-analytical method consists of two parts: 1 physical, which is laboratory testing of concrete mix components in different concrete compositions; 2 analytical, which represents the calculation algorithm for concrete compositions equivalent in concrete strength and workability that comply with the specific conditions of concrete placing. Findings. To solve the problem of designing the concrete composition with the desired properties for railway structures and buildings it was proposed to use the information technology in the form of a developed computer program whose algorithm includes the physico-analytical method for hydraulic concrete composition determination. Originality. The developed concrete composition design method takes into account the basic properties of raw materials, concrete mix and concrete, which are pre-determined. The distinctive feature of physico-analytical method is obtaining of a set of equivalent compositions with a certain concrete mix

  9. Bending characteristics of resin concretes

    Directory of Open Access Journals (Sweden)

    Ribeiro Maria Cristina Santos

    2003-01-01

    Full Text Available In this research work the influence of composition and curing conditions in bending strength of polyester and epoxy concrete is analyzed. Various mixtures of resin and aggregates were considered in view of an optimal combination. The Taguchi methodology was applied in order to reduce the number of tests, and in order to evaluate the influence of various parameters in concrete properties. This methodology is very useful for the planning of experiments. Test results, analyzed by this methodology, shown that the most significant factors affecting bending strength properties of resin concretes are the type of resin, resin content and charge content. An optimal formulation leading to a maximum bending strength was achieved in terms of material parameters.

  10. The bacterial corrosion of concretes

    International Nuclear Information System (INIS)

    Tache, G.

    1998-01-01

    Concrete is a material very sensitive to aging effects and to permanent aggressions. It is an evolutive material in which internal hydration reactions and exchange reactions with the external medium are produced. Moreover, its characteristics tightly depends on factors which are bound to its formulation, to the appropriate choice of materials in which it is constituted, to their qualities and to the conditions of its use. Its aging depends then in a large extent of these different factors and of the adequation between its final characteristics and the solicitations in which it is submitted: physical, mechanical, thermal.. or environmental. This chapter deals particularly with the influence of the bacterial phenomena on concrete. Some recalls are at first given on the principles which govern the concrete durability. Then are approached the phenomena mechanisms. (O.M.)

  11. The Tectonic Potentials of Concrete

    DEFF Research Database (Denmark)

    Egholm Pedersen, Ole

    2013-01-01

    . However, a single concrete casting material, given the use of the right technique that is able to address all these problems, has not been identified, neither in state-of-the-art nor in the case studies. It follows that due to today’s demands for resource optimization and competitiveness it is unlikely......Contemporary techniques for concrete casting in an architectural context are challenged by demands of increased individualization in our built environment, reductions in the use of resources and waste generation. In recent years, new production technologies and strategies that break...... with the industrial paradigm of standardization, have been put forward. This development is carried forward by computers and digital fabrication, but has yet to find its way into the production of building components. With regards to concrete casting, however, existing research do offer advancement towards...

  12. Design of buried concrete encasements

    International Nuclear Information System (INIS)

    Drake, R.M.

    1989-01-01

    The operation of many Department of Energy (DOE) sites requires the transfer of radioactive liquid products from one location to another. DOE Order 6430.1A requires that the transfer pipelines be designed and constructed so that any leakage can be detected and contained before it reaches the environment. One design option often considered to meet this requirement is to place the pipeline in a stainless steel-lined, buried concrete encasement. This provides the engineer with the design challenge to integrate standard structural design principles with unique DOE requirements. The complete design of a buried concrete encasement must consider seismic effects, leak detection, leak confinement, radiation shielding, thermal effects, pipe supports, and constructability. This paper contains a brief discussion of each of these design considerations, based on experience gained during the design of concrete encasements for the Process Facilities Modifications (PFM) project at Hanford

  13. A comparative study between xerographic, computer-assisted overlay generation and animated-superimposition methods in bite mark analyses.

    Science.gov (United States)

    Tai, Meng Wei; Chong, Zhen Feng; Asif, Muhammad Khan; Rahmat, Rabiah A; Nambiar, Phrabhakaran

    2016-09-01

    This study was to compare the suitability and precision of xerographic and computer-assisted methods for bite mark investigations. Eleven subjects were asked to bite on their forearm and the bite marks were photographically recorded. Alginate impressions of the subjects' dentition were taken and their casts were made using dental stone. The overlays generated by xerographic method were obtained by photocopying the subjects' casts and the incisal edge outlines were then transferred on a transparent sheet. The bite mark images were imported into Adobe Photoshop® software and printed to life-size. The bite mark analyses using xerographically generated overlays were done by comparing an overlay to the corresponding printed bite mark images manually. In computer-assisted method, the subjects' casts were scanned into Adobe Photoshop®. The bite mark analyses using computer-assisted overlay generation were done by matching an overlay and the corresponding bite mark images digitally using Adobe Photoshop®. Another comparison method was superimposing the cast images with corresponding bite mark images employing the Adobe Photoshop® CS6 and GIF-Animator©. A score with a range of 0-3 was given during analysis to each precision-determining criterion and the score was increased with better matching. The Kruskal Wallis H test showed significant difference between the three sets of data (H=18.761, p<0.05). In conclusion, bite mark analysis using the computer-assisted animated-superimposition method was the most accurate, followed by the computer-assisted overlay generation and lastly the xerographic method. The superior precision contributed by digital method is discernible despite the human skin being a poor recording medium of bite marks. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Effect of Penetron Admix on the Properties of Concrete

    African Journals Online (AJOL)

    2012r

    2014-07-02

    Jul 2, 2014 ... reducing the emission of greenhouse gases and in increasing the life cycle of concrete structures ..... Reuse of Concrete Block Debris in Concrete. Dissertation (BEng). ... Use of Recycled Concrete Aggregate in. Structural ...

  15. Reliability Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Middleton, C. R.

    This paper is partly based on research performed for the Highways Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: concrete bridges". It contains the details of a methodology which can be used to generate Whole Life (WL) reliability...... profiles. These WL reliability profiles may be used to establish revised rules for concrete bridges. This paper is to some extend based on Thoft-Christensen et. al. [1996], Thoft-Christensen [1996] et. al. and Thoft-Christensen [1996]....

  16. A Failure Criterion for Concrete

    DEFF Research Database (Denmark)

    Ottosen, N. S.

    1977-01-01

    A four-parameter failure criterion containing all the three stress invariants explicitly is proposed for short-time loading of concrete. It corresponds to a smooth convex failure surface with curved meridians, which open in the negative direction of the hydrostatic axis, and the trace in the devi......A four-parameter failure criterion containing all the three stress invariants explicitly is proposed for short-time loading of concrete. It corresponds to a smooth convex failure surface with curved meridians, which open in the negative direction of the hydrostatic axis, and the trace...

  17. Concrete structures under projectile impact

    CERN Document Server

    Fang, Qin

    2017-01-01

    In this book, the authors present their theoretical, experimental and numerical investigations into concrete structures subjected to projectile and aircraft impacts in recent years. Innovative approaches to analyze the rigid, mass abrasive and eroding projectile penetration and perforation are proposed. Damage and failure analyses of nuclear power plant containments impacted by large commercial aircrafts are numerically and experimentally analyzed. Ultra-high performance concrete materials and structures against the projectile impact are developed and their capacities of resisting projectile impact are evaluated. This book is written for the researchers, engineers and graduate students in the fields of protective structures and terminal ballistics.

  18. Quality assurance of polymer concrete

    International Nuclear Information System (INIS)

    Schulz, H.

    1984-01-01

    With polymer concrete, a whole range of organisational and functional measures have to be met in order to assure the required quality with an economic expenditure. Quality assurance begins in the design and does not end in the production, rather includes all fields of the enterprise. The following deals with a particular range of the total complex, the inspection methods for assuring the quality of machine components of polymer concrete, particularly machine tool bases, this being through the control of the raw material, the production and the finished product. (orig.) [de

  19. The steel–concrete interface

    DEFF Research Database (Denmark)

    Angst, Ueli M.; Geiker, Mette Rica; Michel, Alexander

    2017-01-01

    Although the steel–concrete interface (SCI) is widely recognized to influence the durability of reinforced concrete, a systematic overview and detailed documentation of the various aspects of the SCI are lacking. In this paper, we compiled a comprehensive list of possible local characteristics....... It was found that the SCI exhibits significant spatial inhomogeneity along and around as well as perpendicular to the reinforcing steel. The SCI can differ strongly between different engineering structures and also between different members within a structure; particular differences are expected between...

  20. Construction of concrete hot cells

    International Nuclear Information System (INIS)

    1981-12-01

    The standard is to be applied to rooms (hot cells) which are enclosed by a concrete shield and in which radioactive material is handled by remote control. The rooms may be in facilities for experimental purposes (e.g. development of fuel elements and materials or of chemical processes) or in facilities for production purposes (e.g. reprocessing of nuclear fuel or treatment of radioactive wastes). The standard is to give a design hasis for concrete hot cells and their installations which is to be applied by designers, constructors, future users and competent authorities as well as independent experts. (orig.) [de

  1. Construction of concrete hot cells

    International Nuclear Information System (INIS)

    1980-09-01

    The standard is to be applied to rooms (hot cells) which are enclosed by a concrete shield and in which radioactive material is handled by remote control. The rooms may be in facilities for experimental purposes (e.g. development of fuel elements and materials or of chemical processes) or in facilities for production purposes (e.g. reprocessing of nuclear fuel or treatment of radioactive wastes). The standard is to give a design basis for concrete hot cells and their installations which is to be applied by designers, constructors, future users and competent authorities as well as independent experts. (orig.) [de

  2. Surface Chloride Levels in Colorado Structural Concrete

    Science.gov (United States)

    2018-01-01

    This project focused on the chloride-induced corrosion of reinforcing steel in structural concrete. The primary goal of this project is to analyze the surface chloride concentration level of the concrete bridge decks throughout Colorado. The study in...

  3. Modeling damage in concrete pavements and bridges.

    Science.gov (United States)

    2010-09-01

    This project focused on micromechanical modeling of damage in concrete under general, multi-axial loading. A : continuum-level, three-dimensional constitutive model based on micromechanics was developed. The model : accounts for damage in concrete by...

  4. Advances in the material science of concrete

    National Research Council Canada - National Science Library

    Ideker, Jason H; Radlinska, Aleksandra

    2010-01-01

    ... Committee 236, Material Science of Concrete. The session focused on material science aspects of concrete with an emphasis placed on advances in understanding the fundamental scientific topics of cement-based materials, as well as the crucial...

  5. Long-life slab replacement concrete.

    Science.gov (United States)

    2015-03-01

    This research was initiated following reports of high incidence of cracking on FDOT concrete pavement replacement : slab projects. Field slabs were instrumented for data acquisition from high-early-strength concrete pavement : replacement slabs place...

  6. Recycled materials in Portland cement concrete

    Science.gov (United States)

    2000-06-01

    This report pertains to a comprehensive study involving the use of recycled materials in Portland cement concrete. Three different materials were studied including crushed glass (CG), street sweepings (SS), and recycled concrete (RC). Blast furnace s...

  7. Concrete performance using low-degradation aggregates.

    Science.gov (United States)

    2012-06-01

    The durability of Portland cement concrete (PCC) has long been identified as a concern by transportation communities around the United States. In this study, the long-term performance of two batches of concrete incorporating either low-degradation (L...

  8. Influence of processing factors over concrete strength.

    Science.gov (United States)

    Kara, K. A.; Dolzhenko, A. V.; Zharikov, I. S.

    2018-03-01

    Construction of facilities of cast in-situ reinforced concrete poses additional requirements to quality of material, peculiarities of the construction process may sometimes lead to appearance of lamination planes and inhomogeneity of concrete, which reduce strength of the material and structure as a whole. Technology compliance while working with cast in-situ concrete has a significant impact onto the concrete strength. Such process factors as concrete curing, vibration and compaction of the concrete mixture, temperature treatment, etc., when they are countered or inadequately followed lead to a significant reduction in concrete strength. Here, the authors experimentally quantitatively determine the loss of strength in in-situ cast concrete structures due to inadequate following of process requirements, in comparison with full compliance.

  9. Softening behaviour of concrete : numerical research

    NARCIS (Netherlands)

    Bongers, J.P.W.; Rutten, H.S.; Fijneman, H.J.

    1994-01-01

    Experimental research shows, apart from the influence of multiaxial loading conditions, that softening of concrete loaded in compression is accompanied by localization of deformations. Therefore, numerical modelling of concrete material behaviour has to take this effect into account. This implies

  10. Mixed materials for concrete. Concrete yo konwazai ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Kono, K [Tokushima Univ., Tokushima (Japan). Faculty of Engineering

    1994-07-05

    The materials except cement, water and aggregate added into the cement paste, mortar or concrete before the execution of smashing are called mixed materials. The mixed materials are indispensable to the concrete for improving the quality of the fresh concrete as well as the hardened concrete; providing the characteristics suitable for the operation; and increasing the economy. In this paper, the main mixed materials including fly ash, which is the by-product in coal thermoelectric power station; silica fume; micropowder of slag in blast furnace; expansive materials and so on are described summarily. Especially, silica fume is the by-product, which are the super micro-powders with the average size around 0.1 micrometer, collected by the dust-collector from the waste gas generated during the manufacture in the electric furnace of ferrosilicon, which is an alloy iron, or silicon metal used as the deacidificating and desulfurizing agents in the steel production. But the most part thereof is depended on the import since the domestic output is low. 38 refs., 19 figs., 6 tabs.

  11. Evaluation of concrete inlay for continuously reinforced concrete pavement rehabilitation.

    Science.gov (United States)

    2010-06-01

    In 1996, WisDOT constructed a concrete inlay test section on I43 in Manitowoc County. The existing pavement was CRCP constructed in 1978 and was badly deteriorated with punchouts. In the area of the 2777foot test section, the existing paveme...

  12. Study of technological features of tubular compressed concrete members in concreting

    Directory of Open Access Journals (Sweden)

    Voskobiinyk Olena

    2017-01-01

    Full Text Available The technological features of core concreting were analyzed as the main factor in ensuring of strength and reliability of compressed concrete-filled steel tubular (CFST members. We have conducted the analysis of existing concreting methods of CFST members. In this respect, the most dangerous types of possible technological defects of concrete core of CFST members are inhomogeneity along the height, voids, caverns, and concrete “weak spots”. The authors considered the influence of such technological factors of concreting: placeability, time, concrete mixture compaction method, concreting height on the concrete core strength of CFST members. Based on the experimental studies conducted we suggested the regression correlations for determining the concrete strength of CFST members of different length depending on the movability of concrete mixture and a time for its compaction. The authors performed the correlation analysis of technological factors of concreting on the strength of the concrete core. We carried out the comparison of data on the concrete core strength of CFST members, that were determined by non-destructive methods (sclerometer test results, ultrasonic method and direct compression strength tests. We experimentally proved that using movable mixtures with the slump of about 4 – 9 cm the overall variation coefficient of concrete core strength of CFST members along the height reaches nearly 13%. Based on the experimental studies conducted we suggested the guidelines on optimal regimes of concrete compaction during manufacturing CFST members at a construction site environment.

  13. CONCRETE MIX DESIGN FOR STRUCTURES SUBJECTED TO EXPOSURE CLASS XC1 DEPENDING ON CONCRETE COVER

    Directory of Open Access Journals (Sweden)

    O. Yu. Cherniakevich

    2016-01-01

    Full Text Available The reinforced steel corrosion which is the most important problem of reinforced concrete structures durability is generally stipulated for carbonization of concrete surrounding it. Concrete cover calculation at the design stage is predicated one because of the differences in manufacturing conditions and use of constructions. The applying of the probabilistic approaches to the carbonation process modeling allows to get predicated grade of the depth of carbonization of concrete and, thus, to settle minimum concrete cover thickness for a given projected service life of a construction. The procedures for concrete mix design for different strength classes of concrete are described in the article. Current recommendations on assignment of concrete strength class as well as concrete cover are presented. The European Standard EN 206:2013 defines the content requirements for the concrete structures operated in the exposure class XC1, including the minimum values of water-cement ratio, minimum cement content, and minimum strength class of concrete. Since the standard does not include any basis or explanations of the requirements, we made an effort to develop a scientific justification for the mentioned requirements. We developed the probabilistic models for the process of carbonation of concrete based on the concrete mix which was designed using the software VTK-Korroziya. The reinforced concrete structures with concrete cover 20–35 mm operated in the most unfavorable conditions within the exposure class XC1 were analyzed. The corresponding probabilistic calculations of the depth of carbonated concrete are described in the article. 

  14. Summary of Self-compacting Concrete Workability

    OpenAIRE

    GUO Gui-xiang; Duan Hong-jun

    2015-01-01

    On the basis of a large number of domestic and foreign literature, situation and development of self-compacting concrete is introduced. Summary of the compacting theory of self-compacting concrete. And some of the factors affecting the workability of self-compacting concrete were discussed and summarized to a certain extent. Aims to further promote the application and research of self-compacting concrete

  15. Laterally Loaded Partially Prestressed Concrete Piles

    Science.gov (United States)

    1989-09-01

    of an extensive test program onl laterali y ioadeu. partially pr- estressed concrete fender piles. The study Included service load range as well ats...12,000-psi design strength). Configura- tion G utilized 14 r:- estress strand, in an unsymmetric pattern. To provide a uniform concrete prestress of 540...sudden loss in load carrying capacity directly related to the loss of concrete area. The compression concrete fractured longitudinally and along the

  16. Critical Study of Corrosion Damaged Concrete Structures

    OpenAIRE

    Sallehuddin Shah Ayop; John Cairns

    2013-01-01

    Corrosion of steel reinforcement in concrete is one of the major problems with respect to the durability of reinforced concrete structures. The degradation of the structure strength due to reinforcement corrosion decreases its design life. This paper presents the literature study on the influence of the corrosion on concrete structure starting from the mechanism of the corrosion until the deterioration stage and the structural effects of corrosion on concrete structures.

  17. VISCOELASTIC STRUCTURAL MODEL OF ASPHALT CONCRETE

    Directory of Open Access Journals (Sweden)

    V. Bogomolov

    2016-06-01

    Full Text Available The viscoelastic rheological model of asphalt concrete based on the generalized Kelvin model is offered. The mathematical model of asphalt concrete viscoelastic behavior that can be used for calculation of asphalt concrete upper layers of non-rigid pavements for strength and rutting has been developed. It has been proved that the structural model of Burgers does not fully meet all the requirements of the asphalt-concrete.

  18. Probabilistic design of fibre concrete structures

    Science.gov (United States)

    Pukl, R.; Novák, D.; Sajdlová, T.; Lehký, D.; Červenka, J.; Červenka, V.

    2017-09-01

    Advanced computer simulation is recently well-established methodology for evaluation of resistance of concrete engineering structures. The nonlinear finite element analysis enables to realistically predict structural damage, peak load, failure, post-peak response, development of cracks in concrete, yielding of reinforcement, concrete crushing or shear failure. The nonlinear material models can cover various types of concrete and reinforced concrete: ordinary concrete, plain or reinforced, without or with prestressing, fibre concrete, (ultra) high performance concrete, lightweight concrete, etc. Advanced material models taking into account fibre concrete properties such as shape of tensile softening branch, high toughness and ductility are described in the paper. Since the variability of the fibre concrete material properties is rather high, the probabilistic analysis seems to be the most appropriate format for structural design and evaluation of structural performance, reliability and safety. The presented combination of the nonlinear analysis with advanced probabilistic methods allows evaluation of structural safety characterized by failure probability or by reliability index respectively. Authors offer a methodology and computer tools for realistic safety assessment of concrete structures; the utilized approach is based on randomization of the nonlinear finite element analysis of the structural model. Uncertainty of the material properties or their randomness obtained from material tests are accounted in the random distribution. Furthermore, degradation of the reinforced concrete materials such as carbonation of concrete, corrosion of reinforcement, etc. can be accounted in order to analyze life-cycle structural performance and to enable prediction of the structural reliability and safety in time development. The results can serve as a rational basis for design of fibre concrete engineering structures based on advanced nonlinear computer analysis. The presented

  19. Performance of geopolymer concrete in fire

    OpenAIRE

    Zhao, Ren

    2017-01-01

    Portland cement concrete is a world-wide used construction material. However, when Portland cement concrete is exposed to fire, its mechanical properties are deteriorated. The deterioration of concrete is generally caused by the decomposition of the Portland cement hydrate or the thermal incompatibility between cement paste and aggregate. Spalling, which is a violent or non-violent breaking off of layers or pieces of concrete from the surface of a structural element, may also occur when the c...

  20. A device for displaying defects in concrete

    International Nuclear Information System (INIS)

    Zouboff, Vadim; Darnault, Claude; Leloup, J.-C.

    1973-01-01

    The device comprises a common gamma source, located on one side of the concrete block to be examined on the opposite side, a detecting unit comprising a collimator and a photo-multiplier detector connected to a display unit and moving along rails parallel to the concrete block face. That device is used for displaying concrete defects in particular injection deficiencies in the pre-stress sheaths of concrete used for the building of bridges or tunnels [fr