Evaluation of Voids in the Mineral Aggregate for HMA Paving Mixtures

DOT National Transportation Integrated Search

1996-03-01

This study was undertaken (a) to reexamine the rationale behind the minimum VMA : values currently being used, and (b) to quanti~ the relationship between various asphalt film thicknesses and the aging characteristics of the HMA mix, so that an optim...

Evaluation of non-destructive technologies for construction quality control of HMA and PCC pavements in Louisiana.

DOT National Transportation Integrated Search

2013-11-01

Current roadway quality control and quality acceptance (QC/QA) procedures for the Louisiana Department of Transportation and : Development (LADOTD) include coring for thickness, density, and air voids in hot mix asphalt (HMA) pavements and thickness ...

Functional and Biochemical Characterization of Cucumber Genes Encoding Two Copper ATPases CsHMA5.1 and CsHMA5.2*

PubMed Central

Migocka, Magdalena; Posyniak, Ewelina; Maciaszczyk-Dziubinska, Ewa; Papierniak, Anna; Kosieradzaka, Anna

2015-01-01

Plant copper P1B-type ATPases appear to be crucial for maintaining copper homeostasis within plant cells, but until now they have been studied mostly in model plant systems. Here, we present the molecular and biochemical characterization of two cucumber copper ATPases, CsHMA5.1 and CsHMA5.2, indicating a different function for HMA5-like proteins in different plants. When expressed in yeast, CsHMA5.1 and CsHMA5.2 localize to the vacuolar membrane and are activated by monovalent copper or silver ions and cysteine, showing different affinities to Cu+ (Km ∼1 or 0.5 μm, respectively) and similar affinity to Ag+ (Km ∼2.5 μm). Both proteins restore the growth of yeast mutants sensitive to copper excess and silver through intracellular copper sequestration, indicating that they contribute to copper and silver detoxification. Immunoblotting with specific antibodies revealed the presence of CsHMA5.1 and CsHMA5.2 in the tonoplast of cucumber cells. Interestingly, the root-specific CsHMA5.1 was not affected by copper stress, whereas the widely expressed CsHMA5.2 was up-regulated or down-regulated in roots upon copper excess or deficiency, respectively. The copper-induced increase in tonoplast CsHMA5.2 is consistent with the increased activity of ATP-dependent copper transport into tonoplast vesicles isolated from roots of plants grown under copper excess. These data identify CsHMA5.1 and CsHMA5.2 as high affinity Cu+ transporters and suggest that CsHMA5.2 is responsible for the increased sequestration of copper in vacuoles of cucumber root cells under copper excess. PMID:25963145

Development of an Overlay Design Procedure for Composite Pavements

DOT National Transportation Integrated Search

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...

Overlay degradation induced by film stress

NASA Astrophysics Data System (ADS)

Huang, Chi-hao; Liu, Yu-Lin; Luo, Shing-Ann; Yang, Mars; Yang, Elvis; Hung, Yung-Tai; Luoh, Tuung; Yang, T. H.; Chen, K. C.

2017-03-01

The semiconductor industry has continually sought the approaches to produce memory devices with increased memory cells per memory die. One way to meet the increasing storage capacity demand and reduce bit cost of NAND flash memories is 3D stacked flash cell array. In constructing 3D NAND flash memories, increasing the number of stacked layers to build more memory cell number per unit area necessitates many high-aspect-ratio etching processes accordingly the incorporation of thick and unique etching hard-mask scheme has been indispensable. However, the ever increasingly thick requirement on etching hard-mask has made the hard-mask film stress control extremely important for maintaining good process qualities. The residual film stress alters the wafer shape consequently several process impacts have been readily observed across wafer, such as wafer chucking error on scanner, film peeling, materials coating and baking defects, critical dimension (CD) non-uniformity and overlay degradation. This work investigates the overlay and residual order performance indicator (ROPI) degradation coupling with increasingly thick advanced patterning film (APF) etching hard-mask. Various APF films deposited by plasma enhanced chemical vapor deposition (PECVD) method under different deposition temperatures, chemicals combinations, radio frequency powers and chamber pressures were carried out. And -342MPa to +80MPa film stress with different film thicknesses were generated for the overlay performance study. The results revealed the overlay degradation doesn't directly correlate with convex or concave wafer shapes but the magnitude of residual APF film stress, while increasing the APF thickness will worsen the overlay performance and ROPI strongly. High-stress APF film was also observed to enhance the scanner chucking difference and lead to more serious wafer to wafer overlay variation. To reduce the overlay degradation from ever increasingly thick APF etching hard-mask, optimizing the

Evaluation of the Cargill SafeLane surface overlay.

DOT National Transportation Integrated Search

2009-01-01

A recent development in polymer concrete overlays is the Cargill SafeLane surface overlay (SafeLane overlay). The 3/8-in-thick overlay is constructed with epoxy and broadcast aggregates, as are typical multiple-layer epoxy overlays that are used to p...

Statewide implementation of very thin overlays.

DOT National Transportation Integrated Search

2014-10-01

Very thin overlays are defined as overlays where the final lift thickness is 1 inch or less. These are designed : to be high performance overlays in that they have to pass both a rutting (Hamburg Wheel tracking Test) and : reflection cracking (Overla...

Evaluation of non-destructive technologies for construction quality control of HMA and PCC pavements in Louisiana : [tech summary].

DOT National Transportation Integrated Search

2013-11-01

Current roadway quality control and quality acceptance (QC/QA) procedures for the Louisiana Department of Transportation and Development : (LADOTD) include coring for thickness, density, and air voids in hot mix asphalt (HMA) pavements and thickness ...

Evaluation of HMA mixtures containing Sasobit.

DOT National Transportation Integrated Search

2009-07-01

This limited study provided a laboratory and field comparative evaluation of PG 76-22 HMA : hot mix asphalt (HMA) mixture and a mixture containing the additive Sasobit. The : fundamental material characterization testing (asphalt cement binde...

Evaluation of HMA mixtures containing Sasobit.

DOT National Transportation Integrated Search

2009-07-01

This limited study provided a laboratory and field comparative evaluation of PG 76-22 HMA hot mix asphalt (HMA) mixture and a mixture containing the additive Sasobit. The fundamental material characterization testing (asphalt cement binder rh...

Evaluation of non-destructive technologies for construction quality control of HMA and PCC pavements in Louisiana : [research project capsule].

DOT National Transportation Integrated Search

2009-07-01

Current roadway quality control and quality acceptance (QC/QA) procedures : for Louisiana include coring for thickness, density, and air void checks in hot : mix asphalt (HMA) pavements and thickness and compressive strength for : Portland cement con...

Evaluation of cold in-place recycling for rehabilitation of transverse cracking on US 412.

DOT National Transportation Integrated Search

2007-12-01

Successful rehabilitation of transverse cracked hot mix asphalt (HMA) pavements has been a challenge : for state DOTs. Conventional thin HMA overlays allow the rapid return of the existing transverse cracks : and thicker HMA overlays are cost prohibi...

Use of screenings to produce HMA mixtures

DOT National Transportation Integrated Search

2002-10-01

Thin-lift hot mix asphalt (HMA) layers are utilized in almost every maintenance and rehabilitation application. These mix types require smaller maximum particle sizes than most conventional HMA surface layers. Although the primary functions of thin-l...

Diffraction based overlay metrology for α-carbon applications

NASA Astrophysics Data System (ADS)

Saravanan, Chandra Saru; Tan, Asher; Dasari, Prasad; Goelzer, Gary; Smith, Nigel; Woo, Seouk-Hoon; Shin, Jang Ho; Kang, Hyun Jae; Kim, Ho Chul

2008-03-01

Applications that require overlay measurement between layers separated by absorbing interlayer films (such as α- carbon) pose significant challenges for sub-50nm processes. In this paper scatterometry methods are investigated as an alternative to meet these stringent overlay metrology requirements. In this article, a spectroscopic Diffraction Based Overlay (DBO) measurement technique is used where registration errors are extracted from specially designed diffraction targets. DBO measurements are performed on detailed set of wafers with varying α-carbon (ACL) thicknesses. The correlation in overlay values between wafers with varying ACL thicknesses will be discussed. The total measurement uncertainty (TMU) requirements for these layers are discussed and the DBO TMU results from sub-50nm samples are reviewed.

Asphaltic concrete overlays of rigid and flexible pavements : final report.

DOT National Transportation Integrated Search

1980-10-01

This study evaluated the effect of a given thickness of asphaltic concrete overlay in rehabilitating 53 test sections conforming to the experiment design. This factorial design specified various levels of traffic intensity and overlay thickness for b...

Assessment of asphalt interlayer designed on jointed concrete.

DOT National Transportation Integrated Search

2014-11-01

Reflective cracking in hot mix asphalt (HMA) overlays has been a common cause of poor pavement performance in Iowa for : many years. Reflective cracks commonly occur in HMA overlays when deteriorated portland cement concrete is paved over with : HMA....

Asphaltic concrete overlays of rigid and flexible pavements

NASA Astrophysics Data System (ADS)

Kinchen, R. W.; Temple, W. H.

1980-10-01

The development of a mechanistic approach to overlay thickness selection is described. The procedure utilizes a deflection analysis to determine pavement rehabilitation needs. Design guides for selecting the overlay thickness are presented. Tolerable deflection-traffic load relationships and the deflection attenuation properties of asphaltic concrete were developed, representing the subgrade support conditions and properties of materials used in Louisiana. All deflection measurements on asphaltic concrete were corrected for the effect of temperature. Deflection measurements taken before and after overlay were also adjusted to minimize the effects of seasonal subgrade moisture variation.

Ablative overlays for Space Shuttle leading edge ascent heat protection

NASA Technical Reports Server (NTRS)

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.

Mechanistic flexible pavement overlay design program : tech summary.

DOT National Transportation Integrated Search

2009-07-01

The Louisiana Department of Transportation and Development (LADOTD) currently follows the 1993 : AASHTO pavement design guides component analysis method in its fl exible pavement overlay thickness : design. Such an overlay design method, how...

Effective reduction of cadmium accumulation in rice grain by expressing OsHMA3 under the control of the OsHMA2 promoter.

PubMed

Shao, Ji Feng; Xia, Jixing; Yamaji, Naoki; Shen, Ren Fang; Ma, Jian Feng

2018-04-27

Reducing cadmium (Cd) accumulation in rice grain is an important issue for human health. The aim of this study was to manipulate both expression and tissue localization of OsHMA3, a tonoplast-localized Cd transporter, in the roots by expressing it under the control of the OsHMA2 promoter, which shows high expression in different organs including roots, nodes, and shoots. In two independent transgenic lines, the expression of OsHMA3 was significantly enhanced in all organs compared with non-transgenic rice. Furthermore, OsHMA3 protein was detected in the root pericycle cells and phloem region of both the diffuse vascular bundle and the enlarged vascular bundle of the nodes. At the vegetative stage, the Cd concentration in the shoots and xylem sap of the transgenic rice was significantly decreased, but that of the whole roots and root cell sap was increased. At the reproductive stage, the concentration of Cd, but not other essential metals, in the brown rice of transgenic lines was decreased to less than one-tenth that of the non-transgenic rice. These results indicate that expression of OsHMA3 under the control of the OsHMA2 promoter can effectively reduce Cd accumulation in rice grain through sequestering more Cd into the vacuoles of various tissues.

Effective reduction of cadmium accumulation in rice grain by expressing OsHMA3 under the control of the OsHMA2 promoter

PubMed Central

Shao, Ji Feng; Xia, Jixing; Yamaji, Naoki; Shen, Ren Fang; Ma, Jian Feng

2018-01-01

Abstract Reducing cadmium (Cd) accumulation in rice grain is an important issue for human health. The aim of this study was to manipulate both expression and tissue localization of OsHMA3, a tonoplast-localized Cd transporter, in the roots by expressing it under the control of the OsHMA2 promoter, which shows high expression in different organs including roots, nodes, and shoots. In two independent transgenic lines, the expression of OsHMA3 was significantly enhanced in all organs compared with non-transgenic rice. Furthermore, OsHMA3 protein was detected in the root pericycle cells and phloem region of both the diffuse vascular bundle and the enlarged vascular bundle of the nodes. At the vegetative stage, the Cd concentration in the shoots and xylem sap of the transgenic rice was significantly decreased, but that of the whole roots and root cell sap was increased. At the reproductive stage, the concentration of Cd, but not other essential metals, in the brown rice of transgenic lines was decreased to less than one-tenth that of the non-transgenic rice. These results indicate that expression of OsHMA3 under the control of the OsHMA2 promoter can effectively reduce Cd accumulation in rice grain through sequestering more Cd into the vacuoles of various tissues. PMID:29562302

Asphaltic concrete overlays of rigid and flexible pavements : interim report No. 1.

DOT National Transportation Integrated Search

1977-09-01

This study evaluated the effect of a given thickness of asphaltic concrete overlay in rehabilitating 53 test sections conforming to the experiment design. This factorial design specified various levels of traffic intensity and overlay thickness for b...

Development of improved pavement rehabilitation procedures based on FWD backcalculation.

DOT National Transportation Integrated Search

2015-01-01

Hot Mix Asphalt (HMA) overlays are among the most effective maintenance and rehabilitation : alternatives in improving the structural as well as functional performance of flexible pavements. HMA : overlay design procedures can be based on: (1) engine...

A basic guide to overlay design using nondestructive testing equipment data

NASA Astrophysics Data System (ADS)

Turner, Vernon R.

1990-08-01

The purpose of this paper is to provide a basic and concise guide to designing asphalt concrete (AC) overlays over existing AC pavements. The basis for these designs is deflection data obtained from nondestructive testing (NDT) equipment. This data is used in design procedures which produce required overlay thickness or an estimate of remaining pavement life. This guide enables one to design overlays or better monitor the designs being performed by others. This paper will discuss three types of NDT equipment, the Asphalt Institute Overlay Designs by Deflection Analysis and by the effective thickness method as well as a method of estimating remaining pavement life, correlations between NDT equipment and recent correlations in Washington State. Asphalt overlays provide one of the most cost effective methods of improving existing pavements. Asphalt overlays can be used to strengthen existing pavements, to reduce maintenance costs, to increase pavement life, to provide a smoother ride, and to improve skid resistance.

Durability assessment of coarse aggregates for HMA in Maine.

DOT National Transportation Integrated Search

2012-12-01

In this study, Micro-Deval and L.A. Abrasion were used to evaluate the durability of 72 individual : coarse aggregates used for HMA in Maine. Aggregates used in hot-mix asphalt (HMA) must be : durable and resistant to abrasion and degradation. Materi...

Identification of cross-linked amino acids in the protein pair HmaL23-HmaL29 from the 50S ribosomal subunit of the archaebacterium Haloarcula marismortui.

PubMed

Bergmann, U; Wittmann-Liebold, B

1993-03-23

50S ribosomal subunits from the extreme halophilic archaebacterium Haloarcula marismortui were treated with the homobifunctional protein-protein cross-linking reagents diepoxybutane (4 A) and dithiobis(succinimidyl propionate) (12 A). The dominant product with both cross-linking reagents was identified on the protein level as HmaL23-HmaL29, which is homologous to the protein pair L23-L29 from Escherichia coli [Walleczek, J., Martin, T., Redl, B., Stöffler-Meilicke, M., & Stöffler, G. (1989) Biochemistry 28, 4099-4105] and from Bacillus stearothermophilus [Brockmöller, J., & Kamp, R. M. (1986) Biol. Chem. Hoppe-Seyler 367, 925-935]. To reveal the exact cross-linking site in HmaL23-HmaL29, the cross-linked complex was purified on a preparative scale by conventional and high-performance liquid chromatography. After endoproteolytic fragmentation of the protein pair, the amino acids engaged in cross-link formation were unambiguously identified by N-terminal sequence analysis and mass spectrometry of the cross-linked peptides. The cross-link is formed between lysine-57 in the C-terminal region of HmaL29 and the alpha-amino group of the N-terminal serine in protein HmaL23, irrespective of the cross-linking reagent. This result demonstrates that the N-terminal region of protein HmaL23 and the C-terminal domain of HmaL29 are highly flexible so that the distance between the two polypeptide chains can vary by at least 8 A. Comparison of our cross-linking results with those obtained with B. stearothermophilus revealed that the fine structure within this ribosomal domain is at least partially conserved.

Characterization of Alaskan HMA mixtures with the simple performance tester.

DOT National Transportation Integrated Search

2014-05-01

Material characterization provides basic and essential information for pavement design and the evaluation of hot mix asphalt (HMA). : This study focused on the accurate characterization of an Alaskan HMA mixture using an asphalt mixture performance t...

Investigation of electromagnetic gauges for determining in-place HMA density.

DOT National Transportation Integrated Search

2007-05-01

Density is an important component of hot-mix asphalt (HMA) pavement quality and long-term performance. Insufficient density of an : in-place HMA pavement is the most frequently cited construction-related performance problem. : This study evaluated th...

Evolution of the SrTiO3 surface electronic state as a function of LaAlO3 overlayer thickness

NASA Astrophysics Data System (ADS)

Plumb, N. C.; Kobayashi, M.; Salluzzo, M.; Razzoli, E.; Matt, C. E.; Strocov, V. N.; Zhou, K. J.; Shi, M.; Mesot, J.; Schmitt, T.; Patthey, L.; Radović, M.

2017-08-01

The novel electronic properties emerging at interfaces between transition metal oxides, and in particular the discovery of conductivity in heterostructures composed of LaAlO3 (LAO) and SrTiO3 (STO) band insulators, have generated new challenges and opportunities in condensed matter physics. Although the interface conductivity is stabilized when LAO matches or exceeds a critical thickness of 4 unit cells (uc), other phenomena such as a universal metallic state found on the bare surface of STO single crystals and persistent photon-triggered conductivity in otherwise insulating STO-based interfaces raise important questions about the role of the LAO overlayer and the possible relations between vacuum/STO and LAO/STO interfaces. Here, using angle-resolved photoemission spectroscopy (ARPES) on in situ prepared samples complemented by resonant inelastic X-ray scattering (RIXS), we study how the metallic STO surface state evolves during the growth of a crystalline LAO overlayer. In all the studied samples, the character of the conduction bands, their carrier densities, the Ti3+ crystal field, and the response to photon irradiation bear strong similarities. Nevertheless, we report here that studied LAO/STO interfaces exhibit an instability toward an apparent 2 × 1 folding of the Fermi surface at and above a 4 uc thickness threshold, which distinguishes these heterostructures from bare STO and sub-critical-thickness LAO/STO.

Verification of the ODOT overlay design procedure : final report, June 1996.

DOT National Transportation Integrated Search

1996-06-01

The current ODOT overlay design procedure sometimes indicates additional pavement thickness is needed right after the overlay construction. Evaluation of the current procedure reveals that using spreadabiity to back calculate existing pavement modulu...

Overlay design method based on visual pavement distress.

DOT National Transportation Integrated Search

1978-01-01

A method for designing the thickness of overlays for bituminous concrete pavements in Virginia is described. In this method the thickness is calculated by rating the amount and severity of observed pavement distress and determining the total accumula...

Evaluation of hot mix asphalt (HMA) lift thickness.

DOT National Transportation Integrated Search

2009-10-01

The range of lift thicknesses allowed by the Mississippi Department of Transportation has worked well for many years. However, because of the current availability of gravels of sufficient size to crush, modification to the allowed lift thicknesses am...

Mechanistic flexible pavement overlay design program.

DOT National Transportation Integrated Search

2009-07-01

The current Louisiana Department of Transportation and Development (LADOTD) overlay thickness design method follows the Component : Analysis procedure provided in the 1993 AASHTO pavement design guide. Since neither field nor laboratory tests a...

AtHMA4 Drives Natural Variation in Leaf Zn Concentration of Arabidopsis thaliana

PubMed Central

Chen, Zi-Ru; Kuang, Lu; Gao, Yi-Qun; Wang, Ya-Ling; Salt, David E.; Chao, Dai-Yin

2018-01-01

Zinc (Zn) is an essential element for plant growth and development, and Zn derived from crop plants in the diet is also important for human health. Here, we report that genetic variation in Heavy Metal-ATPase 4 (HMA4) controls natural variation in leaf Zn content. Investigation of the natural variation in leaf Zn content in a world-wide collection of 349 Arabidopsis thaliana wild collected accessions identified two accessions, Van-0 and Fab-2, which accumulate significantly lower Zn when compared with Col-0. Both quantitative trait loci (QTL) analysis and bulked segregant analysis (BSA) identified HMA4 as a strong candidate accounting for this variation in leaf Zn concentration. Genetic complementation experiments confirmed this hypothesis. Sequence analysis revealed that a 1-bp deletion in the third exon of HMA4 from Fab-2 is responsible for the lose of function of HMA4 driving the low Zn observed in Fab-2. Unlike in Fab-2 polymorphisms in the promoter region were found to be responsible for the weak function of HMA4 in Van-0. This is supported by both an expression analysis of HMA4 in Van-0 and through a series of T-DNA insertion mutants which generate truncated HMA4 promoters in the Col-0 background. In addition, we also observed that Fab-2, Van-0 and the hma4-2 null mutant in the Col-0 background show enhanced resistance to a combination of high Zn and high Cd in the growth medium, raising the possibility that variation at HMA4 may play a role in environmental adaptation. PMID:29545819

AtHMA4 Drives Natural Variation in Leaf Zn Concentration of Arabidopsis thaliana.

PubMed

Chen, Zi-Ru; Kuang, Lu; Gao, Yi-Qun; Wang, Ya-Ling; Salt, David E; Chao, Dai-Yin

2018-01-01

Zinc (Zn) is an essential element for plant growth and development, and Zn derived from crop plants in the diet is also important for human health. Here, we report that genetic variation in Heavy Metal-ATPase 4 ( HMA4 ) controls natural variation in leaf Zn content. Investigation of the natural variation in leaf Zn content in a world-wide collection of 349 Arabidopsis thaliana wild collected accessions identified two accessions, Van-0 and Fab-2, which accumulate significantly lower Zn when compared with Col-0. Both quantitative trait loci (QTL) analysis and bulked segregant analysis (BSA) identified HMA4 as a strong candidate accounting for this variation in leaf Zn concentration. Genetic complementation experiments confirmed this hypothesis. Sequence analysis revealed that a 1-bp deletion in the third exon of HMA4 from Fab-2 is responsible for the lose of function of HMA4 driving the low Zn observed in Fab-2. Unlike in Fab-2 polymorphisms in the promoter region were found to be responsible for the weak function of HMA4 in Van-0. This is supported by both an expression analysis of HMA4 in Van-0 and through a series of T-DNA insertion mutants which generate truncated HMA4 promoters in the Col-0 background. In addition, we also observed that Fab-2, Van-0 and the hma4-2 null mutant in the Col-0 background show enhanced resistance to a combination of high Zn and high Cd in the growth medium, raising the possibility that variation at HMA4 may play a role in environmental adaptation.

Aggregate absorption in HMA mixtures.

DOT National Transportation Integrated Search

2013-12-01

Designing hot mix asphalt (HMA) that will perform for many years is a complex balancing act of selecting an : appropriate design asphalt binder content that is sufficiently high to provide durability but not so high as to lead : to rutting problems. ...

Determination of thickness of thin turbid painted over-layers using micro-scale spatially offset Raman spectroscopy

NASA Astrophysics Data System (ADS)

Conti, Claudia; Realini, Marco; Colombo, Chiara; Botteon, Alessandra; Bertasa, Moira; Striova, Jana; Barucci, Marco; Matousek, Pavel

2016-12-01

We present a method for estimating the thickness of thin turbid layers using defocusing micro-spatially offset Raman spectroscopy (micro-SORS). The approach, applicable to highly turbid systems, enables one to predict depths in excess of those accessible with conventional Raman microscopy. The technique can be used, for example, to establish the paint layer thickness on cultural heritage objects, such as panel canvases, mural paintings, painted statues and decorated objects. Other applications include analysis in polymer, biological and biomedical disciplines, catalytic and forensics sciences where highly turbid overlayers are often present and where invasive probing may not be possible or is undesirable. The method comprises two stages: (i) a calibration step for training the method on a well characterized sample set with a known thickness, and (ii) a prediction step where the prediction of layer thickness is carried out non-invasively on samples of unknown thickness of the same chemical and physical make up as the calibration set. An illustrative example of a practical deployment of this method is the analysis of larger areas of paintings. In this case, first, a calibration would be performed on a fragment of painting of a known thickness (e.g. derived from cross-sectional analysis) and subsequently the analysis of thickness across larger areas of painting could then be carried out non-invasively. The performance of the method is compared with that of the more established optical coherence tomography (OCT) technique on identical sample set. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

Design of overlays for flexible pavements based on AASHTO road test data.

DOT National Transportation Integrated Search

1978-01-01

The need for a suitable method of designing the thickness of overlays and predicting the performance of the overlaid pavement has recently been recognized. The AASHTO Road Tests included studies on 99 overlays, but they failed to produce conclusive r...

Investigation of HMA compactability using GPR technique

NASA Astrophysics Data System (ADS)

Plati, Christina; Georgiou, Panos; Loizos, Andreas

2014-05-01

In-situ field density is often regarded as one of the most important controls used to ensure that an asphalt pavement being placed is of high quality. The achieved density results from the effectiveness of the applied compaction mode on the Hot Mix Asphalt (HMA) layer. It is worthwhile mentioning that the proper compaction of HMA increases pavement fatigue life, decreases the amount of permanent deformation or rutting, reduces the amount of oxidation or aging, decreases moisture damage or stripping, increases strength and internal stability, and may decrease slightly the amount of low-temperature cracking that may occur in the mix. Conventionally, the HMA density in the field is assessed by direct destructive methods, including through the cutting of samples or drilling cores. These methods are characterized by a high accuracy, although they are intrusive and time consuming. In addition, they provide local information, i.e. information only for the exact test location. To overcome these limitations, the use of non-intrusive techniques is often recommended. The Ground Penetrating Radar (GPR) technique is an example of a non-intrusive technique that has been increasingly used for pavement investigations over the years. GPR technology is practical and application-oriented with the overall design concept, as well as the hardware, usually dependent on the target type and the material composing the target and its surroundings. As the sophistication of operating practices increases, the technology matures and GPR becomes an intelligent sensor system. The intelligent sensing deals with the expanded range of GPR applications in pavements such as determining layer thickness, detecting subsurface distresses, estimating moisture content, detecting voids and others. In addition, the practice of using GPR to predict in-situ field density of compacted asphalt mixture material is still under development and research; however the related research findings seem to be promising

The polarization of Sb overlayers on NiMnSb(100)

NASA Astrophysics Data System (ADS)

Komesu, Takashi; Borca, C. N.; Jeong, Hae-Kyung; Dowben, P. A.; Ristoiu, Delia; Nozières, J. P.; Stadler, Shane; Idzerda, Y. U.

2000-08-01

We have investigated the induced polarization of paramagnetic Sb overlayers on the Heusler alloy NiMnSb. From combined X-ray absorption spectroscopy (XAS) and spin-polarized inverse photoemission spectroscopy (SPIPES), we can assign some of the unoccupied states of the Heusler alloy NiMnSb. With increasing thickness of the Sb overlayer, there is a decline in the density of states near the Fermi energy, as expected for a semimetal overlayer on a metallic substrate. While the Sb is polarized by the ferromagnetic NiMnSb substrate, consistent with the expectations of mean field theory, the polarization at the center of the surface/overlayer Brillouin zone cannot be easily related to the induced magnetization.

Evaluation of various hot mix asphalt pavement thicknesses over rubblized concrete pavement.

DOT National Transportation Integrated Search

2011-07-01

In 1999, the Wisconsin DOT constructed two test sections as part of a rubblized PCC pavement project on I-39 to evaluate whether : increased HMA thickness could extend the pavement system's service life. Design thicknesses of the control and test sec...

Accelerated Fatigue Resistance of Thick CAD/CAM Composite Resin Overlays Bonded with Light- and Dual-polymerizing Luting Resins.

PubMed

Goldberg, Jack; Güth, Jan-Frederik; Magne, Pascal

To evaluate the accelerated fatigue resistance of thick CAD/CAM composite resin overlays luted with three different bonding methods. Forty-five sound human second mandibular molars were organized and distributed into three experimental groups. All teeth were restored with a 5-mm-thick CAD/CAM composite resin overlay. Group A: immediate dentin sealing (IDS) with Optibond FL and luted with light-polymerizing composite (Herculite XRV). Group B: IDS with Optibond FL and luted with dual-polymerizing composite (Nexus 3). Group C: direct luting with Optibond FL and dual-polymerizing composite (Nexus 3). Masticatory forces at a frequency of 5 Hz were simulated using closed-loop servo-hydraulics and forces starting with a load of 200 N for 5000 cycles, followed by steps of 400, 600, 800, 1000, 1200 and 1400 N for a maximum of 30,000 cycles. Each step was applied through a flat steel cylinder at a 45-degree angle under submerged conditions. The fatigue test generated one failure in group A, three failures in group B, and no failures in group C. The survival table analysis for the fatigue test did not demonstrate any significant difference between the groups (p = 0.154). The specimens that survived the fatigue test were set up for the load-to-failure test with a limit of 4600 N. The survival table analysis for the load-to-failure test demonstrates an average failure load of 3495.20 N with survival of four specimens in group A, an average failure load of 4103.60 N with survival of six specimens in group B, and an average failure load of 4075.33 N with survival of nine specimens in group C. Pairwise comparisons revealed no significant differences (p < 0.016 after Bonferroni correction). Within the limitations of this in vitro study, it can be concluded that although the dual-polymerizing luting material seems to provide better results under extreme conditions, light-polymerizing luting composites in combination with IDS are not contraindicated with thick restorations.

Overlay accuracy fundamentals

NASA Astrophysics Data System (ADS)

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 < 0.5nm, it becomes crucial to include also systematic error contributions which affect the accuracy of the metrology. Here we discuss fundamental aspects of overlay accuracy and a methodology to improve accuracy significantly. We identify overlay mark imperfections and their interaction with the metrology technology, as the main source of overlay inaccuracy. The most important type of mark imperfection is mark asymmetry. Overlay mark asymmetry leads to a geometrical ambiguity in the definition of overlay, which can be ~1nm or less. It is shown theoretically and in simulations that the metrology may enhance the effect of overlay mark asymmetry significantly and lead to metrology inaccuracy ~10nm, much larger than the geometrical ambiguity. The analysis is carried out for two different overlay metrology technologies: Imaging overlay and 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.

Evaluation of the MIT-Scan-T2 for non-destructive PCC pavement thickness determination.

DOT National Transportation Integrated Search

2008-07-01

The MIT-Scan-T2 device is marketed as a non-destructive way to determine pavement thickness on both : HMA and PCC pavements. PCC pavement thickness determination is an important incentivedisincentive : measurement for the Iowa DOT and contractors. Th...

Image-based overlay measurement using subsurface ultrasonic resonance force microscopy

NASA Astrophysics Data System (ADS)

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.

Best practice for using RAS in HMA.

DOT National Transportation Integrated Search

2012-04-01

The use of recycled asphalt shingles (RAS) in hot-mix asphalt (HMA) mixtures has the potential to : significantly reduce the cost of asphalt paving mixes while conserving energy and preserving the : environment. This report documents the best practic...

Residual stress determination in an overlay dissimilar welded pipe by neutron diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woo, Wan Chuck; Em, Vyacheslav; Hubbard, Camden R

2011-01-01

Residual stresses were determined through the thickness of a dissimilar weld overlay pipe using neutron diffraction. The specimen has a complex joining structure consisting of a ferritic steel (SA508), austenitic steel (F316L), Ni-based consumable (Alloy 182), and overlay of Ni-base superalloy (Alloy 52M). It simulates pressurized nozzle components, which have been a critical issue under the severe crack condition of nuclear power reactors. Two neutron diffractometers with different spatial resolutions have been utilized on the identical specimen for comparison. The macroscopic 'stress-free' lattice spacing (d{sub o}) was also obtained from both using a 2-mm width comb-like coupon. The results showmore » significant changes in residual stresses from tension (300-400 MPa) to compression (-600 MPa) through the thickness of the dissimilar weld overlay pipe specimen.« less

Asphaltic mixture compaction and density validation : research brief.

DOT National Transportation Integrated Search

2017-02-01

Research Objectives: : Evaluate HMA longitudinal joint type, method and compaction data to produce specification recommendations to ensure the highest density at longitudinal joints : Evaluate thin lift overlay HMA and provide recommendations...

Practices and guidelines for temporary transverse HMA tapers.

DOT National Transportation Integrated Search

2010-05-01

During hot mix asphalt (HMA) construction and rehabilitation, partially completed pavements are often opened to : traffic between construction periods. This results in transverse dropoffs at the transition between pavements of : different elevations....

New possibilities for tuning ultrathin cobalt film magnetic properties by a noble metal overlayer.

PubMed

Kisielewski, M; Maziewski, A; Tekielak, M; Wawro, A; Baczewski, L T

2002-08-19

Complementary multiscale magneto-optical studies based on the polar Kerr effect are carried out on an ultrathin cobalt wedge covered with a silver wedge and subsequently with the Au thick layer. A few monolayers of Ag are found to have a substantial effect on magnetic anisotropy, the coercivity field, and Kerr rotation. The silver overlayer thickness-driven magnetic reorientation from easy axis to easy plane generates a new type of 90 degrees magnetic wall for cobalt thicknesses between 1.3 and 1.8 nm. The tuning of the wall width in a wide range is possible. Tailoring of the overlayer structure can be used for ultrathin film magnetic patterning.

Field Evaluation of Temperature Differential in HMA Mixtures

DOT National Transportation Integrated Search

2012-05-15

Segregation is a common occurrence in hot mix asphalt (HMA) construction. The two types of : segregation encountered are gradation segregation and thermal segregation. This investigation report : involves mainly thermal segregation, which occurs when...

Electronic structure of uranium overlayers on magnesium and aluminium

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Overlay improvement methods with diffraction based overlay and integrated metrology

NASA Astrophysics Data System (ADS)

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.

Evaluation of Asphalt Pavement Analyzer for HMA Design

DOT National Transportation Integrated Search

1999-06-01

Rutting is a common problem in hot mix asphalt pavements, particularly in hot climates and at intersections. The Asphalt Pavement Analyzer (APA) is a laboratory accelerated loading equipment that can be used to evaluate rutting potential of HMA. This...

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

DOT National Transportation Integrated Search

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...

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

NASA Astrophysics Data System (ADS)

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.

Poplar maintains zinc homeostasis with heavy metal genes HMA4 and PCS1

PubMed Central

Adams, Joshua P.; Adeli, Ardeshir; Hsu, Chuan-Yu; Harkess, Richard L.; Page, Grier P.; dePamphilis, Claude W.; Schultz, Emily B.; Yuceer, Cetin

2011-01-01

Perennial woody species, such as poplar (Populus spp.) must acquire necessary heavy metals like zinc (Zn) while avoiding potential toxicity. Poplar contains genes with sequence homology to genes HMA4 and PCS1 from other species which are involved in heavy metal regulation. While basic genomic conservation exists, poplar does not have a hyperaccumulating phenotype. Poplar has a common indicator phenotype in which heavy metal accumulation is proportional to environmental concentrations but excesses are prevented. Phenotype is partly affected by regulation of HMA4 and PCS1 transcriptional abundance. Wild-type poplar down-regulates several transcripts in its Zn-interacting pathway at high Zn levels. Also, overexpressed PtHMA4 and PtPCS1 genes result in varying Zn phenotypes in poplar; specifically, there is a doubling of Zn accumulation in leaf tissues in an overexpressed PtPCS1 line. The genomic complement and regulation of poplar highlighted in this study supports a role of HMA4 and PCS1 in Zn regulation dictating its phenotype. These genes can be altered in poplar to change its interaction with Zn. However, other poplar genes in the surrounding pathway may maintain the phenotype by inhibiting drastic changes in heavy metal accumulation with a single gene transformation. PMID:21504875

Evaluation of Longitudinal Joints of HMA Pavements in Tennessee

DOT National Transportation Integrated Search

2010-05-01

Longitudinal joints between lanes of hot-mix asphalt (HMA) pavements are commonly susceptible to moisture damage and other failures. In 2006, the Tennessee Department of Transportation (TDOT) identified longitudinal joint failure as one of the major ...

The metal-binding domain of wheat heavy metal ATPase 2 (TaHMA2) is involved in zinc/cadmium tolerance and translocation in Arabidopsis.

PubMed

Qiao, Kun; Gong, Liang; Tian, Yanbao; Wang, Hong; Chai, Tuanyao

2018-06-23

Cysteine in the N-terminal metal-binding domain (N-MBD) of TaHMA2 participates in Zn 2+ /Cd 2+ binding and translocation in Arabidopsis. Wheat heavy metal ATPase 2 (TaHMA2) can transport Zn 2+ and Cd 2+ across membranes. A previous study showed that cysteine (Cys) and glutamate residues in the N-terminal metal-binding domain (N-MBD) were necessary for metal-binding and translocation of TaHMA2 in yeast. However, the function of TaHMA2 in plants was not fully revealed. In this study, we investigated the roles of the CCxxE and CPC motifs in the N-MBD and the N/C-terminal regions of TaHMA2 in Zn 2+ /Cd 2+ translocation in root and shoot of Arabidopsis. Compared with the wild type, overexpression of TaHMA2 and the TaHMA2 derivative (glutamic substituted for alanine from CCxxE) in Arabidopsis increased root length, fresh weight and enhanced Zn 2+ /Cd 2+ root-to-shoot translocation. The plants with a truncated N/C-terminal of TaHMA2 were impaired in Zn 2+ /Cd 2+ tolerance and translocation, while mutagenesis of Cys in the N-MBD reduced the tolerance and transport activity of TaHMA2, suggesting the involvement of Cys in Zn 2+ /Cd 2+ binding and translocation in Arabidopsis. This study therefore provides a theoretical possibility for the application of TaHMA2 in transgenic breeding to regulate metal element balance in crop plants.

Design and performance evaluation of very thin overlays in Texas.

DOT National Transportation Integrated Search

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...

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

NASA Astrophysics Data System (ADS)

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.

HvHMA2, a P1B-ATPase from Barley, Is Highly Conserved among Cereals and Functions in Zn and Cd Transport

PubMed Central

Mills, Rebecca F.; Peaston, Kerry A.; Runions, John; Williams, Lorraine E.

2012-01-01

Manipulation of crops to improve their nutritional value (biofortification) and optimisation of plants for removal of toxic metals from contaminated soils (phytoremediation) are major goals. Identification of membrane transporters with roles in zinc and cadmium transport would be useful for both aspects. The P1B-ATPases play important roles in heavy metal allocation and detoxification in Arabidopsis and it is now important to elucidate their roles in monocots. We identified nine P1B-ATPases in barley and this study focuses on the functional characterization of HvHMA2, providing evidence for its role in heavy metal transport. HvHMA2 was cloned using information from EST analysis and 5′ RACE. It possesses the conserved aspartate that is phosphorylated during the reaction cycle of P-type pumps and has motifs and key residues characteristic of P1B-ATPases, falling into the P1B-2 subclass. Homologous sequences occur in three major sub-families of the Poaceae (Gramineae). Heterologous expression in Saccharomyces cerevisiae demonstrates that HvHMA2 functions as a Zn and Cd pump. Mutagenesis studies show that proposed cation coordination sites of the P1B-2 pumps are crucial for the metal responses conferred by HvHMA2 in yeast. HvHMA2 expression suppresses the Zn-deficient phenotype of the Arabidopsis hma2hma4 mutant indicating that HvHMA2 functions as a Zn pump in planta and could play a role in root to shoot Zn transport. When expressed in Arabidopsis, HvHMA2 localises predominantly to the plasma membrane. PMID:22880063

Single-Layer Limit of Metallic Indium Overlayers on Si(111).

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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.

Risk analysis of ODOT's HMA percent within limits (PWL) specification.

DOT National Transportation Integrated Search

2007-08-01

The Oklahoma Department of Transportation (ODOT) is considering switching its method of payment : for hot mix asphalt (HMA) construction from their current procedure to a Percent Within Limits (PWL) : specification. Quality characteristics are percen...

Fuzzy Decision-Making Fuser (FDMF) for Integrating Human-Machine Autonomous (HMA) Systems with Adaptive Evidence Sources.

PubMed

Liu, Yu-Ting; Pal, Nikhil R; Marathe, Amar R; Wang, Yu-Kai; Lin, Chin-Teng

2017-01-01

A brain-computer interface (BCI) creates a direct communication pathway between the human brain and an external device or system. In contrast to patient-oriented BCIs, which are intended to restore inoperative or malfunctioning aspects of the nervous system, a growing number of BCI studies focus on designing auxiliary systems that are intended for everyday use. The goal of building these BCIs is to provide capabilities that augment existing intact physical and mental capabilities. However, a key challenge to BCI research is human variability; factors such as fatigue, inattention, and stress vary both across different individuals and for the same individual over time. If these issues are addressed, autonomous systems may provide additional benefits that enhance system performance and prevent problems introduced by individual human variability. This study proposes a human-machine autonomous (HMA) system that simultaneously aggregates human and machine knowledge to recognize targets in a rapid serial visual presentation (RSVP) task. The HMA focuses on integrating an RSVP BCI with computer vision techniques in an image-labeling domain. A fuzzy decision-making fuser (FDMF) is then applied in the HMA system to provide a natural adaptive framework for evidence-based inference by incorporating an integrated summary of the available evidence (i.e., human and machine decisions) and associated uncertainty. Consequently, the HMA system dynamically aggregates decisions involving uncertainties from both human and autonomous agents. The collaborative decisions made by an HMA system can achieve and maintain superior performance more efficiently than either the human or autonomous agents can achieve independently. The experimental results shown in this study suggest that the proposed HMA system with the FDMF can effectively fuse decisions from human brain activities and the computer vision techniques to improve overall performance on the RSVP recognition task. This conclusion

Fuzzy Decision-Making Fuser (FDMF) for Integrating Human-Machine Autonomous (HMA) Systems with Adaptive Evidence Sources

PubMed Central

Liu, Yu-Ting; Pal, Nikhil R.; Marathe, Amar R.; Wang, Yu-Kai; Lin, Chin-Teng

2017-01-01

A brain-computer interface (BCI) creates a direct communication pathway between the human brain and an external device or system. In contrast to patient-oriented BCIs, which are intended to restore inoperative or malfunctioning aspects of the nervous system, a growing number of BCI studies focus on designing auxiliary systems that are intended for everyday use. The goal of building these BCIs is to provide capabilities that augment existing intact physical and mental capabilities. However, a key challenge to BCI research is human variability; factors such as fatigue, inattention, and stress vary both across different individuals and for the same individual over time. If these issues are addressed, autonomous systems may provide additional benefits that enhance system performance and prevent problems introduced by individual human variability. This study proposes a human-machine autonomous (HMA) system that simultaneously aggregates human and machine knowledge to recognize targets in a rapid serial visual presentation (RSVP) task. The HMA focuses on integrating an RSVP BCI with computer vision techniques in an image-labeling domain. A fuzzy decision-making fuser (FDMF) is then applied in the HMA system to provide a natural adaptive framework for evidence-based inference by incorporating an integrated summary of the available evidence (i.e., human and machine decisions) and associated uncertainty. Consequently, the HMA system dynamically aggregates decisions involving uncertainties from both human and autonomous agents. The collaborative decisions made by an HMA system can achieve and maintain superior performance more efficiently than either the human or autonomous agents can achieve independently. The experimental results shown in this study suggest that the proposed HMA system with the FDMF can effectively fuse decisions from human brain activities and the computer vision techniques to improve overall performance on the RSVP recognition task. This conclusion

Cost effective prevention of reflective cracking of composite pavement : research project capsule.

DOT National Transportation Integrated Search

2008-12-01

Reflection cracks are caused by discontinuities (cracks or joints) in underlying layers, which : propagate through a hot-mix asphalt (HMA) overlay due to continuous movement at the crack : prompted by thermal and traffic loading. If the new overlay i...

Amino acid sequences of the ribosomal proteins HL30 and HmaL5 from the archaebacterium Halobacterium marismortui.

PubMed

Hatakeyama, T; Hatakeyama, T

1990-07-06

The complete amino acid sequences of the ribosomal proteins HL30 and HmaL5 from the archaebacterium Halobacterium marismortui were determined. Protein HL30 was found to be acetylated at its N-terminal amino acid and shows homology to the eukaryotic ribosomal proteins YL34 from yeast and RL31 from rat. Protein HmaL5 was homologous to the protein L5 from Escherichia coli and Bacillus stearothermophilus as well as to YL16 from yeast. HmaL5 shows more similarities to its eukaryotic counterpart than to eubacterial ones.

A nanometric Rh overlayer on a metal foil surface as a highly efficient three-way catalyst.

PubMed

Misumi, Satoshi; Yoshida, Hiroshi; Hinokuma, Satoshi; Sato, Tetsuya; Machida, Masato

2016-07-08

Pulsed arc-plasma (AP) deposition of an Rh overlayer on an Fe-Cr-Al stainless steel foil produced a composite material that exhibited high activity for automotive three-way catalysis (TWC). The AP pulses deposited metallic Rh nanoparticles 1-3 nm in size, whose density on the surface increased with the number of pulses. This led to coalescence and grain growth on the foil surface and the eventual formation of a uniform two-dimensional Rh overlayer. Full coverage of the 51 μm-thick flat foil by a 3.2 nm-thick Rh overlayer was achieved after 1,000 pulses. A simulated TWC reaction using a miniature honeycomb fabricated using flat and corrugated foils with the Rh overlayers exhibited successful light-off at a practical gaseous hourly space velocity of 1.2 × 10(5) h(-1). The turnover frequency for the NO-CO reaction over the metallic honeycomb catalyst was ca. 80-fold greater than that achieved with a reference Rh/ZrO2-coated cordierite honeycomb prepared using a conventional wet impregnation and slurry coating procedure. Despite the nonporosity and low surface area of the foil-supported Rh overlayer compared with conventional powder catalysts (Rh/ZrO2), it is a promising alternative design for more efficient automotive catalysts that use less Rh loading.

Evaluation of HMA overlays in Illinois.

DOT National Transportation Integrated Search

2008-09-01

The Illinois Department of Transportation (IDOT) has evaluated the performance of the pavements in Illinois in a : variety of studies over the years. Since those studies were conducted, several changes in IDOT practices, policies, and : procedures ha...

Changes in fatty acid content and composition between wild type and CsHMA3 overexpressing Camelina sativa under heavy-metal stress.

PubMed

Park, Won; Feng, Yufeng; Kim, Hyojin; Suh, Mi Chung; Ahn, Sung-Ju

2015-09-01

Under heavy-metal stress, CsHMA3 overexpressing transgenic Camelina plants displayed not only a better quality, but also a higher quantity of unsaturated fatty acids in their seeds compared with wild type. Camelina sativa L. belongs to the Brassicaceae family and is frequently used as a natural vegetable oil source, as its seeds contain a high content of fatty acids. In this study, we observed that, when subjected to heavy metals (Cd, Co, Zn and Pb), the seeds of CsHMA3 (Heavy-Metal P1B-ATPase 3) transgenic lines retained their original golden yellow color and smooth outline, unlike wild-type seeds. Furthermore, we investigated the fatty acids content and composition of wild type and CsHMA3 transgenic lines after heavy metal treatments compared to the control. The results showed higher total fatty acid amounts in seeds of CsHMA3 transgenic lines compared with those in wild-type seeds under heavy-metal stresses. In addition, the compositions of unsaturated fatty acids-especially 18:1 (oleic acid), 18:2 (linoleic acid; only in case of Co treatment), 18:3 (linolenic acid) and 20:1 (eicosenoic acid)-in CsHMA3 overexpressing transgenic lines treated with heavy metals were higher than those of wild-type seeds under the same conditions. Furthermore, reactive oxygen species (ROS) contents in wild-type leaves and roots when treated with heavy metal were higher than in CsHMA3 overexpressing transgenic lines. These results indicate that overexpression of CsHMA3 affects fatty acid composition and content-factors that are responsible for the fuel properties of biodiesel-and can alleviate ROS accumulation caused by heavy-metal stresses in Camelina. Due to these factors, we propose that CsHMA3 transgenic Camelina can be used for phytoremediation of metal-contaminated soil as well as for oil production.

Validation of contractor HMA testing data in the materials acceptance process.

DOT National Transportation Integrated Search

2010-08-01

"This study conducted an analysis of the SCDOT HMA specification. A Research Steering Committee comprised of SCDOT, FHWA, and Industry representatives provided oversight of the process. The research process included a literature review, a brief surve...

Non-nuclear methods for HMA density measurements : final report, June 2008.

DOT National Transportation Integrated Search

2008-05-01

Non-nuclear methods for the measurement of hot-mix asphalt (HMA) density offer the ability to take numerous density readings in a very short period of time, without the need for intensive licensing, training, and maintenance efforts common to nuclear...

Overlay metrology for double patterning processes

NASA Astrophysics Data System (ADS)

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

Diffraction based overlay re-assessed

NASA Astrophysics Data System (ADS)

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.

Hot mix asphalt (HMA) characterization for the 2002 AASHTO design guide.

DOT National Transportation Integrated Search

2008-09-30

The two study objectives were to conduct dynamic modulus and APA rutting tests of selected Mississippi HMA mixtures. A total of twenty-five mixtures were tested including aggregate combinations of gravel and gravel/limestone; 9.5mm, 12.5mm and 19.0mm...

Evaluation of a conventional chip seal under an overlay to mitigate reflective cracking (informal).

DOT National Transportation Integrated Search

2015-03-01

The Billings District initiated an experimental project in placing a conventional : chip seal (as an interlayer) on an existing pavement prior to an overlay : (composed of a 0.25 PMS thickness). The intent of the chip seal (CS) was to : seal exist...

A T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in Arabidopsis thaliana has a defect in the water-water cycle of photosynthesis.

PubMed

Higuchi, Mieko; Ozaki, Hiroshi; Matsui, Minami; Sonoike, Kintake

2009-03-03

The water-water cycle is the electron flow through scavenging enzymes for the reactive species of oxygen in chloroplasts, and is proposed to play a role in alternative electron sink in photosynthesis. Here we showed that the water-water cycle is impaired in the T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in chloroplasts. Chlorophyll fluorescence under steady state was not affected in hma1, indicating that photosynthetic electron transport under normal condition was not impaired. Under electron acceptor limited conditions, however, hma1 showed distinguished phenotype in chlorophyll fluorescence characteristics. The most severe phenotype of hma1 could be observed in high (0.1%) CO(2) concentrations, indicating that hma1 has the defect other than photorespiration. The transient increase of chlorophyll fluorescence upon the cessation of the actinic light as well as the NPQ induction of chlorophyll fluorescence revealed that the two pathways of cyclic electron flow around PSI, NDH-pathway and FQR-pathway, are both intact in hma1. Based on the NPQ induction under 0% oxygen condition, we conclude that the water-water cycle is impaired in hma1, presumably due to the decreased level of Cu/Zn SOD in the mutant. Under high CO(2) condition, hma1 exhibited slightly higher NPQ induction than wild type plants, while this increase of NPQ in hma1 was suppressed when hma1 was crossed with crr2 having a defect in NDH-mediated PSI cyclic electron flow. We propose that the water-water cycle and NDH-mediated pathways might be regulated compensationally with each other especially when photorespiration is suppressed.

Advanced overlay analysis through design based metrology

NASA Astrophysics Data System (ADS)

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.

0-6744 : new HMA shear resistance and rutting test for Texas mixes.

DOT National Transportation Integrated Search

2014-08-01

Traditionally run at one test temperature (122F), the : Hamburg wheel tracking test (HWTT) (Figure 1) has a : proven history of successfully identifying and screening : hot-mix asphalt (HMA) mixes that are prone to rutting : and/or susceptible to m...

The performances of different overlay mark types at 65nm node on 300-mm wafers

NASA Astrophysics Data System (ADS)

Tseng, H. T.; Lin, Ling-Chieh; Huang, I. H.; Lin, Benjamin S.; Huang, Chin-Chou K.; Huang, Chien-Jen

2005-05-01

The integrated circuit (IC) manufacturing factories have measured overlay with conventional "box-in-box" (BiB) or "frame-in-frame" (FiF) structures for many years. Since UMC played as a roll of world class IC foundry service provider, tighter and tighter alignment accuracy specs need to be achieved from generation to generation to meet any kind of customers' requirement, especially according to International Technology Roadmap for Semiconductors (ITRS) 2003 METROLOGY section1. The process noises resulting from dishing, overlay mark damaging by chemical mechanism polishing (CMP), and the variation of film thickness during deposition are factors which can be very problematic in mark alignment. For example, the conventional "box-in-box" overlay marks could be damaged easily by CMP, because the less local pattern density and wide feature width of the box induce either dishing or asymmetric damages for the measurement targets, which will make the overlay measurement varied and difficult. After Advanced Imaging Metrology (AIM) overlay targets was introduced by KLA-Tencor, studies in the past shown AIM was more robust in overlay metrology than conventional FiF or BiB targets. In this study, the applications of AIM overlay marks under different process conditions will be discussed and compared with the conventional overlay targets. To evaluate the overlay mark performance against process variation on 65nm technology node in 300-mm wafer, three critical layers were chosen in this study. These three layers were Poly, Contact, and Cu-Metal. The overlay targets used for performance comparison were BiB and Non-Segmented AIM (NS AIM) marks. We compared the overlay mark performance on two main areas. The first one was total measurement uncertainty (TMU)3 related items that include Tool Induced Shift (TIS) variability, precision, and matching. The other area is the target robustness against process variations. Based on the present study AIM mark demonstrated an equal or better

Thickness measurement of a thin hetero-oxide film with an interfacial oxide layer by X-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Kim, Kyung Joong; Lee, Seung Mi; Jang, Jong Shik; Moret, Mona

2012-02-01

The general equation Tove = L cos θ ln(Rexp/R0 + 1) for the thickness measurement of thin oxide films by X-ray photoelectron spectroscopy (XPS) was applied to a HfO2/SiO2/Si(1 0 0) as a thin hetero-oxide film system with an interfacial oxide layer. The contribution of the thick interfacial SiO2 layer to the thickness of the HfO2 overlayer was counterbalanced by multiplying the ratio between the intensity of Si4+ from a thick SiO2 film and that of Si0 from a Si(1 0 0) substrate to the intensity of Si4+ from the HfO2/SiO2/Si(1 0 0) film. With this approximation, the thickness levels of the HfO2 overlayers showed a small standard deviation of 0.03 nm in a series of HfO2 (2 nm)/SiO2 (2-6 nm)/Si(1 0 0) films. Mutual calibration with XPS and transmission electron microscopy (TEM) was used to verify the thickness of HfO2 overlayers in a series of HfO2 (1-4 nm)/SiO2 (3 nm)/Si(1 0 0) films. From the linear relation between the thickness values derived from XPS and TEM, the effective attenuation length of the photoelectrons and the thickness of the HfO2 overlayer could be determined.

Effect of end-point compaction on superpave hot mix asphalt (HMA) mix designs.

DOT National Transportation Integrated Search

2004-01-09

In the Superpave hot mix asphalt (HMA) mix design system, gyratory specime ns are compacted to varying levels of initial (Ninitial), : design (Ndesign) and maximum (Nmaximum) gyrations. Initially, in the Superpave system, specimens were compacted to ...

The overlay tester (OT) : comparison with other crack test methods and recommendations for surrogate crack tests.

DOT National Transportation Integrated Search

2012-10-01

Presently, one of the principal performance concerns of hot-mix asphalt (HMA) pavements is premature : cracking, particularly of HMA surfacing mixes. Regrettably, however, while many USA transportation agencies have : implemented design-level tests t...

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

NASA Astrophysics Data System (ADS)

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 < 3nm), there seems to remain a large margin. Does that mean that today's leading edge Fab has an easy life? Unfortunately not, as other contributors affecting overlay are 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.

Overlay accuracy with respect to device scaling

NASA Astrophysics Data System (ADS)

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.

Structure determination of a multilayer with an island-like overlayer using hard x-ray photoelectron spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isomura, N., E-mail: isomura@mosk.tytlabs.co.jp; Kataoka, K.; Horibuchi, K.

We use hard X-ray photoelectron spectroscopy (HAXPES) to obtain the surface structure of a multilayer Au/SiO{sub 2}/Si substrate sample with an island-like overlayer. Photoelectron intensities are measured as a function of incident photon energy (PE) and take-off angle (TOA, measured from the sample surface). The Au layer coverage and Au and SiO{sub 2} layer thicknesses are obtained by the PE dependence, and are used for the following TOA analysis. The Au island lateral width in the cross section is obtained by the TOA dependence, including information about surface roughness, in consideration of the island shadowing at small TOAs. In bothmore » cases, curve-fitting analysis is conducted. The surface structure, which consists of layer thicknesses, overlayer coverage and island width, is determined nondestructively by a combination of PE and TOA dependent HAXPES measurements.« less

Improved performance of JPCP overlays.

DOT National Transportation Integrated Search

2013-07-01

The overall performance of Michigan concrete overlays has been good. However, some recent JPCP overlay projects have developed premature distress with signs of pumping. It is suspected that lack of drainage was the main cause for the distresses rangi...

Gas Selectivity Control in Co3O4 Sensor via Concurrent Tuning of Gas Reforming and Gas Filtering using Nanoscale Hetero-Overlayer of Catalytic Oxides.

PubMed

Jeong, Hyun-Mook; Jeong, Seong-Yong; Kim, Jae-Hyeok; Kim, Bo-Young; Kim, Jun-Sik; Abdel-Hady, Faissal; Wazzan, Abdulaziz A; Al-Turaif, Hamad Ali; Jang, Ho Won; Lee, Jong-Heun

2017-11-29

Co 3 O 4 sensors with a nanoscale TiO 2 or SnO 2 catalytic overlayer were prepared by screen-printing of Co 3 O 4 yolk-shell spheres and subsequent e-beam evaporation of TiO 2 and SnO 2 . The Co 3 O 4 sensors with 5 nm thick TiO 2 and SnO 2 overlayers showed high responses (resistance ratios) to 5 ppm xylene (14.5 and 28.8) and toluene (11.7 and 16.2) at 250 °C with negligible responses to interference gases such as ethanol, HCHO, CO, and benzene. In contrast, the pure Co 3 O 4 sensor did not show remarkable selectivity toward any specific gas. The response and selectivity to methylbenzenes and ethanol could be systematically controlled by selecting the catalytic overlayer material, varying the overlayer thickness, and tuning the sensing temperature. The significant enhancement of the selectivity for xylene and toluene was attributed to the reforming of less reactive methylbenzenes into more reactive and smaller species and oxidative filtering of other interference gases, including ubiquitous ethanol. The concurrent control of the gas reforming and oxidative filtering processes using a nanoscale overlayer of catalytic oxides provides a new, general, and powerful tool for designing highly selective and sensitive oxide semiconductor gas sensors.

Polymer concrete overlay on SH-51, bridge deck

NASA Astrophysics Data System (ADS)

Borg, T. M.

1982-06-01

A thin resinous overlay was placed on a sound bridge deck in Oklahoma to evaluate its performance over one year using various physical tests. The evaluation shows how well the overlay protects the reinforcing steel from corrosion due to deicing salts. The steps leading to the construction of the overlay are detailed as well as the actual placing of the overlay. The results of various physical tests are reported for both before and after the overlay.

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

NASA Astrophysics Data System (ADS)

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.

Enhacement of intrafield overlay using a design based metrology system

NASA Astrophysics Data System (ADS)

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.

Stripping in HMA Mixtures: State of the Art and Critical Review of Test Methods

DOT National Transportation Integrated Search

1988-09-01

This report presents review summaries of the state-of-the-art regarding stripping in hot mix asphalt (HMA) mixtures. The review stresses efforts concerned with methods development, evaluation and presents a critical review of select methods including...

Stripping in HMA mixtures : state-of-the-art and critical review of test methods

DOT National Transportation Integrated Search

1988-09-01

This report presents review summaries of the state-of-the-art : regarding stripping in hot mix asphalt (HMA) mixtures. The review stresses efforts concerned with methods development, evaluation and presents a critical review of select methods includi...

Advanced diffraction-based overlay for double patterning

NASA Astrophysics Data System (ADS)

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.

How big does a coloured overlay have to be?

PubMed

Waldie, Michelle; Wilkins, Arnold

2004-01-01

Coloured overlays and coloured lenses can both increase reading speed, but when they do their colour is not necessarily the same, suggesting that the beneficial effects of a coloured filter might depend upon the area of the visual field that it colours. We investigated the effects of overlays on reading speed and varied the size of the overlay and the colour of the surround. Children who had been assessed with coloured overlays were required to read a passage of randomly ordered common words. The words were printed in black ink as a block of text positioned centrally on an A4 page of white paper in landscape orientation. The speed of reading was compared under four conditions: (1) without an overlay; (2) with an overlay of the chosen colour covering the entire page; (3) with the overlay cut so that it just covered the text but left the margin white; (4) with the overlay of the chosen colour covering the text but with the margin coloured a complementary colour, using a second overlay. The children who were using an overlay read more quickly with the overlay; those who were no longer using the overlay did not. Although the block of text covered less than half the page, the colour and nature of the margin did not affect reading speed significantly. These findings suggest that in order to be effective at improving reading speed an overlay needs to cover the text, but not necessarily the remainder of the page, which means that smaller overlays may sometimes be sufficient.

Diffraction-based overlay metrology for double patterning technologies

NASA Astrophysics Data System (ADS)

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.

Investigation of early distress in Wisconsin rubblized pavements.

DOT National Transportation Integrated Search

2011-07-01

This study investigated premature distress formation in Wisconsin HMA overlays of rubblized concrete pavement. The premature : distress was tented transverse cracking, which formed during the winter season and significantly affected pavement ride. Th...

Specifications for use of WMA technology in delivering HMA and non-conventional mixtures : [brief].

DOT National Transportation Integrated Search

2015-03-01

Recent national research efforts have focused on the development and evaluation of warm mix : asphalt (WMA) technologies as a means to reduce the environmental impact and enhance : the performance of conventional hot mix asphalt (HMA). As a result, d...

Real cell overlay measurement through design based metrology

NASA Astrophysics Data System (ADS)

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

HMA shear resistance, permanent deformation, and rutting tests for Texas mixes : year-1 report.

DOT National Transportation Integrated Search

2014-04-01

Traditionally run at one test temperature (122F), the Hamburg Wheel Tracking Test (HWTT) has a proven : history of identifying hot-mix asphalt (HMA) mixes that are moisture susceptible and/or prone to rutting. However, : with the record summer temp...

A Study of Longitudinal Joint Construction Techniques in HMA Pavements (Interim Report - Colorado Project)

DOT National Transportation Integrated Search

1996-02-01

There is a need to identify suitable longitudinal joint construction techniques for multilane hot mix asphalt (HMA) pavements, which can minimize or eliminate cracking at the joint and/or ravelling adjacent to the joint. It is believed that the longi...

A comparison of advanced overlay technologies

NASA Astrophysics Data System (ADS)

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.

An Overlay Architecture for Throughput Optimal Multipath Routing

DTIC Science & Technology

2017-01-14

1 An Overlay Architecture for Throughput Optimal Multipath Routing Nathaniel M. Jones, Georgios S. Paschos, Brooke Shrader, and Eytan Modiano...decisions. In this work, we study an overlay architecture for dynamic routing such that only a subset of devices (overlay nodes) need to make dynamic routing...a legacy network. Network overlays are frequently used to deploy new communication architectures in legacy networks [13]. To accomplish this, messages

Hybrid overlay metrology for high order correction by using CDSEM

NASA Astrophysics Data System (ADS)

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).

Device overlay method for high volume manufacturing

NASA Astrophysics Data System (ADS)

Lee, Honggoo; Han, Sangjun; Kim, Youngsik; Kim, Myoungsoo; Heo, Hoyoung; Jeon, Sanghuck; Choi, DongSub; Nabeth, Jeremy; Brinster, Irina; Pierson, Bill; Robinson, John C.

2016-03-01

Advancing technology nodes with smaller process margins require improved photolithography overlay control. Overlay control at develop inspection (DI) based on optical metrology targets is well established in semiconductor manufacturing. Advances in target design and metrology technology have enabled significant improvements in overlay precision and accuracy. One approach to represent in-die on-device as-etched overlay is to measure at final inspection (FI) with a scanning electron microscope (SEM). Disadvantages to this approach include inability to rework, limited layer coverage due to lack of transparency, and higher cost of ownership (CoO). A hybrid approach is investigated in this report whereby infrequent DI/FI bias is characterized and the results are used to compensate the frequent DI overlay results. The bias characterization is done on an infrequent basis, either based on time or triggered from change points. On a per-device and per-layer basis, the optical target overlay at DI is compared with SEM on-device overlay at FI. The bias characterization results are validated and tracked for use in compensating the DI APC controller. Results of the DI/FI bias characterization and sources of variation are presented, as well as the impact on the DI correctables feeding the APC system. Implementation details in a high volume manufacturing (HVM) wafer fab will be reviewed. Finally future directions of the investigation will be discussed.

Implementation of Texas asphalt concrete overlay design system.

DOT National Transportation Integrated Search

2014-08-01

An asphalt overlay design system was developed for Texas Department of Transportation (TxDOT) under : Research Project 0-5123. The new overlay design system, named the Texas Asphalt Concrete Overlay : Design System (TxACOL), can help pavement enginee...

Diffraction-based overlay for spacer patterning and double patterning technology

NASA Astrophysics Data System (ADS)

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.

Development of an economical thin, quiet, long-lasting, high friction surface layer for economical use in Illinois, volume 2 : field construction, field testing, and engineering benefit analysis.

DOT National Transportation Integrated Search

2013-03-01

This project provides techniques to improve hot-mix asphalt (HMA) overlays specifically through the use of : special additives and innovative surfacing technologies with aggregates that are locally available in Illinois. The : ultimate goal is to imp...

Fabrication of magnetic bubble memory overlay

NASA Technical Reports Server (NTRS)

1973-01-01

Self-contained magnetic bubble memory overlay is fabricated by process that employs epitaxial deposition to form multi-layered complex of magnetically active components on single chip. Overlay fabrication comprises three metal deposition steps followed by subtractive etch.

Flexible overlays for rigid pavements : final report, February 2010.

DOT National Transportation Integrated Search

2010-02-01

Approximately 45% of the New Jersey Department of Transportations (NJDOT) roadways are : composite (hot mix asphalt overlying Portland cement concrete). Hot mix asphalt (HMA) is used as : the overlying material because of its inexpensive nature wh...

High-throughput electrical characterization for robust overlay lithography control

NASA Astrophysics Data System (ADS)

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.

Use of moisture induced stress testing to evaluate stripping potential of hot mix asphalt (HMA).

DOT National Transportation Integrated Search

2012-07-01

Stripping of hot mix asphalt (HMA) in the field is an ongoing issue for many Departments of Transportation : (DOTs). A leading cause of stripping is hydraulic scouring. The Moisture Induced Stress Tester (MIST) is a recently : developed technology th...

Validation of contractor HMA testing data in the materials acceptance process - phase II : final report.

DOT National Transportation Integrated Search

2016-08-01

This study conducted an analysis of the SCDOT HMA specification. A Research Steering Committee provided oversight : of the process. The research process included extensive statistical analyses of test data supplied by SCDOT. : A total of 2,789 AC tes...

MnDOT thin whitetopping selection procedures : final report.

DOT National Transportation Integrated Search

2017-06-01

This report provides an integrated selection procedure for evaluating whether an existing hot-mix asphalt (HMA) pavement is an appropriate candidate for a bonded concrete overlay of asphalt (BCOA). The selection procedure includes (1) a desk review, ...

HMA shear resistance, permanent deformation, and rutting tests for Texas mixes : final year-2 report.

DOT National Transportation Integrated Search

2014-11-01

Traditionally run at one test temperature (122F), the Hamburg wheel tracking test (HWTT) has a proven : history of identifying hot mix asphalt (HMA) mixes that are moisture susceptible and/or prone to rutting. However, : with the record summer temp...

Refinement of current WisDOT HMA mixture application guidelines related to NMAS and aggregate characteristics.

DOT National Transportation Integrated Search

2014-01-01

Current Wisconsin Department of Transportation (WisDOT) Specifications limit nominal maximum aggregate : size (NMAS) of hot-mix asphalt (HMA) to 12.5 mm in the surface layer and 19.0 mm in lower layers. This : potentially places unnecessary limits on...

SEM based overlay measurement between resist and buried patterns

NASA Astrophysics Data System (ADS)

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.

Polymer concrete overlay on Beulah Road Bridge : interim report no. 1--installation and initial condition of overlay.

DOT National Transportation Integrated Search

1982-01-01

The installation of a thin polymer concrete overlay on the Beulah Road bridge demonstrates that an overlay of low permeability and high skid resistance can be successfully installed by maintenance forces with a minimum of disruption to traffic, appro...

Passivation of surface states of α-Fe2O3(0001) surface by deposition of Ga2O3 overlayers: A density functional theory study.

PubMed

Ulman, Kanchan; Nguyen, Manh-Thuong; Seriani, Nicola; Gebauer, Ralph

2016-03-07

There is a big debate in the community regarding the role of surface states of hematite in the photoelectrochemical water splitting. Experimental studies on non-catalytic overlayers passivating the hematite surface states claim a favorable reduction in the overpotential for the water splitting reaction. As a first step towards understanding the effect of these overlayers, we have studied the system Ga2O3 overlayers on hematite (0001) surfaces using first principles computations in the PBE+U framework. Our computations suggest that stoichiometric terminations of Ga2O3 overlayers are energetically more favored than the bare surface, at ambient oxygen chemical potentials. Energetics suggest that the overlayers prefer to grow via a layer-plus-island (Stranski-Krastanov) growth mode with a critical layer thickness of 1-2 layers. Thus, a complete wetting of the hematite surface by an overlayer of gallium oxide is thermodynamically favored. We establish that the effect of deposition of the Ga2O3 overlayers on the bare hematite surface is to passivate the surface states for the stoichiometric termination. For the oxygen terminated surface which is the most stable termination under photoelectrochemical conditions, the effect of deposition of the Ga2O3 overlayer is to passivate the hole-trapping surface state.

Polymer concrete overlay on the Big Swan Creek Bridge : condition of overlay after two years in service.

DOT National Transportation Integrated Search

1986-01-01

The multiple-layer polymer concrete overlay on the Big Swan Creek Bridge was soundly bonded to the base concrete and providing excellent protection against the infiltration of chloride ions after 2 years in service. Evaluations of this and PC overlay...

Assessment of asphalt interlayer designed on jointed concrete : [tech transfer summary].

DOT National Transportation Integrated Search

2014-11-01

Based on the substantial reduction in reflective cracking and only marginal : cost increases from using the interlayer on this research project, it is : recommended that future hot mix asphalt (HMA) overlay projects in Iowa : consider using the crack...

Patterned wafer geometry grouping for improved overlay control

NASA Astrophysics Data System (ADS)

Lee, Honggoo; Han, Sangjun; Woo, Jaeson; Park, Junbeom; Song, Changrock; Anis, Fatima; Vukkadala, Pradeep; Jeon, Sanghuck; Choi, DongSub; Huang, Kevin; Heo, Hoyoung; Smith, Mark D.; Robinson, John C.

2017-03-01

Process-induced overlay errors from outside the litho cell have become a significant contributor to the overlay error budget including non-uniform wafer stress. Previous studies have shown the correlation between process-induced stress and overlay and the opportunity for improvement in process control, including the use of patterned wafer geometry (PWG) metrology to reduce stress-induced overlay signatures. Key challenges of volume semiconductor manufacturing are how to improve not only the magnitude of these signatures, but also the wafer to wafer variability. This work involves a novel technique of using PWG metrology to provide improved litho-control by wafer-level grouping based on incoming process induced overlay, relevant for both 3D NAND and DRAM. Examples shown in this study are from 19 nm DRAM manufacturing.

Final report : Polymer concrete overlay on Beulah Road Bridge : condition of overlay after one year in service.

DOT National Transportation Integrated Search

1983-01-01

An evaluation of the thin polymer concrete overlay placed on the Beulah Road bridge indicates that the overlay is securely bonded to the base concrete and is providing low permeability and high skid resistance after 1 year of service life. The lane c...

Scatterometry or imaging overlay: a comparative study

NASA Astrophysics Data System (ADS)

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

Evaluation of Tack Coat Bond Strength Tests

DOT National Transportation Integrated Search

2018-05-01

Poor bonding between asphalt pavement overlays and the substrate pavement layer can greatly influence the long term performance of hot mix asphalt (HMA) in the form of premature cracking and fatigue. The primary method to achieve bonding between laye...

Reflective crack mitigation guide for flexible pavements.

DOT National Transportation Integrated Search

2015-09-01

Reflective cracks form in pavements when hot-mix asphalt (HMA) overlays are placed over jointed and/or severely cracked rigid : and flexible pavements. In the first part of the research, survival analysis was conducted to identify the most appropriat...

Mitigation strategies for reflective cracking in pavements : [research project capsule].

DOT National Transportation Integrated Search

2013-12-01

Refl ection cracks are caused by discontinuities (cracks or joints) in underlying layers, : which propagate through hot-mix asphalt (HMA) overlay due to continuous movement : at the crack prompted by thermal expansion and traffi c loading. If the new...

Characterization of HMA mixtures containing high reclaimed asphalt pavement content with crumb rubber additives : [technical summary].

DOT National Transportation Integrated Search

2013-03-01

With the increase in hot mix asphalt (HMA) mixtures prices continuously climbing, highway agencies and owners are continually : searching for methods to decrease material costs and maximize their benefi ts with no compromise in performance. One su...

Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol overlayers and avidin-biotin technology

PubMed Central

Hynninen, Ville; Vuori, Leena; Hannula, Markku; Tapio, Kosti; Lahtonen, Kimmo; Isoniemi, Tommi; Lehtonen, Elina; Hirsimäki, Mika; Toppari, J. Jussi; Valden, Mika; Hytönen, Vesa P.

2016-01-01

A straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E. coli was reduced by more than 65%. Moreover, the potential of the overlayer to be further modified was demonstrated by successfully coupling biotinylated alkaline phosphatase (bAP) to a silane-PEG-biotin overlayer via avidin-biotin bridges. The activity of the immobilized enzyme was shown to be well preserved without compromising the achieved antifouling properties. Overall, the simple solution-based approach enables the tailoring of SS to enhance its activity for biomedical and biotechnological applications. PMID:27381834

Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol overlayers and avidin-biotin technology

NASA Astrophysics Data System (ADS)

Hynninen, Ville; Vuori, Leena; Hannula, Markku; Tapio, Kosti; Lahtonen, Kimmo; Isoniemi, Tommi; Lehtonen, Elina; Hirsimäki, Mika; Toppari, J. Jussi; Valden, Mika; Hytönen, Vesa P.

2016-07-01

A straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E. coli was reduced by more than 65%. Moreover, the potential of the overlayer to be further modified was demonstrated by successfully coupling biotinylated alkaline phosphatase (bAP) to a silane-PEG-biotin overlayer via avidin-biotin bridges. The activity of the immobilized enzyme was shown to be well preserved without compromising the achieved antifouling properties. Overall, the simple solution-based approach enables the tailoring of SS to enhance its activity for biomedical and biotechnological applications.

New generation mix-designs : laboratory-field testing and modifications to Texas HMA mix-design procedures.

DOT National Transportation Integrated Search

2012-10-01

Recent changes to the Texas hot mix asphalt (HMA) mix-design procedures such as adaption of the higher-stiffer PG asphalt-binder grades and the Hamburg test have ensured that the mixes that are routinely used on the Texas highways are not prone to ru...

Reflective Cracking of Flexible Pavements Phase I and II Final Recommendations

DOT National Transportation Integrated Search

2008-02-02

This report summarizes all the findings and recommendations from the Phase I and Phase II of the Nevada Department of Transportation (NDOT) study initiated in 2006 to mitigate reflective cracking in hot mix asphalt (HMA) overlays. Based on the analys...

Very-early-strength latex-modified concrete overlay.

DOT National Transportation Integrated Search

1998-12-01

This paper describes the installation and condition of the first two very-early-strength latex modified concrete (LMC-VE) overlays constructed for the Virginia Department of Transportation. The overlays were prepared with a special blended cement rat...

A map overlay error model based on boundary geometry

USGS Publications Warehouse

Gaeuman, D.; Symanzik, J.; Schmidt, J.C.

2005-01-01

An error model for quantifying the magnitudes and variability of errors generated in the areas of polygons during spatial overlay of vector geographic information system layers is presented. Numerical simulation of polygon boundary displacements was used to propagate coordinate errors to spatial overlays. The model departs from most previous error models in that it incorporates spatial dependence of coordinate errors at the scale of the boundary segment. It can be readily adapted to match the scale of error-boundary interactions responsible for error generation on a given overlay. The area of error generated by overlay depends on the sinuosity of polygon boundaries, as well as the magnitude of the coordinate errors on the input layers. Asymmetry in boundary shape has relatively little effect on error generation. Overlay errors are affected by real differences in boundary positions on the input layers, as well as errors in the boundary positions. Real differences between input layers tend to compensate for much of the error generated by coordinate errors. Thus, the area of change measured on an overlay layer produced by the XOR overlay operation will be more accurate if the area of real change depicted on the overlay is large. The model presented here considers these interactions, making it especially useful for estimating errors studies of landscape change over time. ?? 2005 The Ohio State University.

Very-Early-Strength Latex-Modified Concrete Overlays

DOT National Transportation Integrated Search

1998-12-01

This report describes the installation and condition of the first two very-early-strength latex-modified concrete (LMC-VE) overlays to be constructed for the Virginia Department of Transportation. The overlays were prepared with a special blended cem...

In-cell overlay metrology by using optical metrology tool

NASA Astrophysics Data System (ADS)

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.

Determination of the PG binder grade to use in a RAP mix

DOT National Transportation Integrated Search

2001-04-01

The use of Recycled Asphalt Pavement (RAP) in new Hot Mix Asphalt (HMA) has become routine in the part few years. This practice is spurred by the increased amounts of pavement being milled off prior to overlaying. Using RAP has economical and environ...

Technical memo, project 0-6132 : task 6, test sections in the districts.

DOT National Transportation Integrated Search

2011-05-01

This Tech Memo presents a summary of the field performance evaluation of the TTI sections in : Laredo District (Webb County) that was conducted at the end of winter on May 3rd 2011; eight : months after HMA overlay placement. Field performance tests ...

Technical memo, project 0-6132 : task 6 - test sections in the districts.

DOT National Transportation Integrated Search

2011-05-01

This Tech Memo presents a summary of the field performance evaluation of the TTI sections in : Laredo District (Webb County) that was conducted at the end of winter on May 3rd 2011; eight : months after HMA overlay placement. Field performance tests ...

Hybrid overlay metrology with CDSEM in a BEOL patterning scheme

NASA Astrophysics Data System (ADS)

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).

High early strength latex modified concrete overlay.

DOT National Transportation Integrated Search

1988-01-01

This report describes the condition of the first high early strength latex modified concrete (LMC-HE) overlay to be constructed for the Virginia Department of Transportation. The overlay was prepared with type III cement and with more cement and less...

Evaluating diffraction-based overlay

NASA Astrophysics Data System (ADS)

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.

Engineering high Zn in tomato shoots through expression of AtHMA4 involves tissue-specific modification of endogenous genes.

PubMed

Kendziorek, Maria; Klimecka, Maria; Barabasz, Anna; Borg, Sören; Rudzka, Justyna; Szczęsny, Paweł; Antosiewicz, Danuta Maria

2016-08-12

To increase the Zn level in shoots, AtHMA4 was ectopically expressed in tomato under the constitutive CaMV 35S promoter. However, the Zn concentration in the shoots of transgenic plants failed to increase at all tested Zn levels in the medium. Modification of Zn root/shoot distribution in tomato expressing 35S::AtHMA4 depended on the concentration of Zn in the medium, thus indicating involvement of unknown endogenous metal-homeostasis mechanisms. To determine these mechanisms, those metal-homeostasis genes that were expressed differently in transgenic and wild-type plants were identified by microarray and RT-qPCR analysis using laser-assisted microdissected RNA isolated from two root sectors: (epidermis + cortex and stele), and leaf sectors (upper epidermis + palisade parenchyma and lower epidermis + spongy parenchyma). Zn-supply-dependent modification of Zn root/shoot distribution in AtHMA4-tomato (increase at 5 μM Zn, no change at 0.5 μM Zn) involved tissue-specific, distinct from that in the wild type, expression of tomato endogenous genes. First, it is suggested that an ethylene-dependent pathway underlies the detected changes in Zn root/shoot partitioning, as it was induced in transgenic plants in a distinct way depending on Zn exposure. Upon exposure to 5 or 0.5 μM Zn, in the epidermis + cortex of the transgenics' roots the expression of the Strategy I Fe-uptake system (ethylene-dependent LeIRT1 and LeFER) was respectively lower or higher than in the wild type and was accompanied by respectively lower or higher expression of the identified ethylene genes (LeNR, LeACO4, LeACO5) and of LeChln. Second, the contribution of LeNRAMP2 expression in the stele is shown to be distinct for wild-type and transgenic plants at both Zn exposures. Ethylene was also suggested as an important factor in a pathway induced in the leaves of transgenic plants by high Zn in the apoplast, which results in the initiation of loading of the excess Zn into the

Polymer concrete overlay on the Big Swan Creek Bridge : interim report no. 1--installation and initial condition of overlay.

DOT National Transportation Integrated Search

1984-01-01

The installation of a thin polymer concrete overlay on the Big Swan Creek Bridge provides further evidence that an overlay of low permeability can be soundly bonded to a concrete bridge deck by maintenance forces with a minimum of disruption to traff...

Robotic weld overlay coatings for erosion control

NASA Astrophysics Data System (ADS)

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.

Evaluation of pavement bleeding problem on I-55 in Illinois

DOT National Transportation Integrated Search

1991-01-01

Shortly after construction fat spots began to appear throughout the project on a 3 inch hot mix asphalt (HMA) overlay of an existing PCC pavement. The fat spots appeared to occur at end of truck loads. After time the fat spots developed into potholes...

Technical memo, project 0-6132 : task 6 - test sections in the districts.

DOT National Transportation Integrated Search

2011-05-01

This Tech Memo presents a summary of the field performance evaluation of the TTI sections on US 59 in Panola County (Atlanta District) that was conducted at the end of winter on May 13th 2011; one year after HMA overlay placement. Field performance t...

Technical memo, project 0-6132 : task 6 - test sections in the districts.

DOT National Transportation Integrated Search

2011-01-01

This Tech Memo presents a summary of the field performance evaluation of the TTI sections on US 59 in Panola County (Atlanta District) that was conducted at the end of summer on October 12th 2010; five months after HMA overlay placement. Field perfor...

Preparation for implementation of the mechanistic-empirical pavement design guide in Michigan : part 1 - HMA mixture characterization.

DOT National Transportation Integrated Search

2013-03-01

This is the final report of the Part 1 (HMA Mixture Characterization) of the Preparation for Implementation of the Mechanistic-Empirical Pavement Design Guide in Michigan project. The main objectives of the Part 1 were (i) to conduct a literatu...

Augmenting reality in Direct View Optical (DVO) overlay applications

NASA Astrophysics Data System (ADS)

Hogan, Tim; Edwards, Tim

2014-06-01

The integration of overlay displays into rifle scopes can transform precision Direct View Optical (DVO) sights into intelligent interactive fire-control systems. Overlay displays can provide ballistic solutions within the sight for dramatically improved targeting, can fuse sensor video to extend targeting into nighttime or dirty battlefield conditions, and can overlay complex situational awareness information over the real-world scene. High brightness overlay solutions for dismounted soldier applications have previously been hindered by excessive power consumption, weight and bulk making them unsuitable for man-portable, battery powered applications. This paper describes the advancements and capabilities of a high brightness, ultra-low power text and graphics overlay display module developed specifically for integration into DVO weapon sight applications. Central to the overlay display module was the development of a new general purpose low power graphics controller and dual-path display driver electronics. The graphics controller interface is a simple 2-wire RS-232 serial interface compatible with existing weapon systems such as the IBEAM ballistic computer and the RULR and STORM laser rangefinders (LRF). The module features include multiple graphics layers, user configurable fonts and icons, and parameterized vector rendering, making it suitable for general purpose DVO overlay applications. The module is configured for graphics-only operation for daytime use and overlays graphics with video for nighttime applications. The miniature footprint and ultra-low power consumption of the module enables a new generation of intelligent DVO systems and has been implemented for resolutions from VGA to SXGA, in monochrome and color, and in graphics applications with and without sensor video.

The Sapphire (0001) Surface, Clean and with d-metal Overlayers: Density Functional - LDA Results

NASA Astrophysics Data System (ADS)

Verdozzi, C.; Jennison, D. R.; Schultz, P. A.; Sears, M. P.

1998-03-01

Previous theoretical work for the a-Al2O3(0001) surface mostly used very thin slabs, and limited theoretical information is available on the binding of metal overlayers. Also, no systematic information is available about the dependence of the metal-ceramic interaction on metal coverage. We present here results using the local density approximation for the structural and electronic properties of the a-Al2O3(0001) surface, with and without d-metal overlayers Pt, Ag, Cu, and with sufficiently thick slabs to find the bottom of the unusually large and deep surface relaxation in this material. Our thick slab site-optimized calculations are performed for 1, 2/3 and 1/3 monolayer (ML) coverage. The adhesion energy and the nature of the interfacial bond vary greatly with metal coverage and can be understood in terms of the relative roles of the surface Madelung potential and the strength of the lateral metal-metal bond. Our study should in principle succeed in bracketing the phenomenology of adhesion and wetting at least for the right-most part of the d-metal periodic table. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000. Corresponding author: claudio@sandia.gov.

New generation HMA mix designs : accelerated pavement testing of a type C mix with the ALF machine.

DOT National Transportation Integrated Search

2012-09-01

Recent changes to the Texas hot-mix asphalt (HMA) mix-design procedures, such as the adaption of the higher-stiffer performance-grade asphalt-binder grades and the Hamburg test, have ensured that the mixes that are routinely used on Texas highways ar...

Optical resonance analysis of reflected long period fiber gratings with metal film overlay

NASA Astrophysics Data System (ADS)

Zhang, Guiju; Cao, Bing; Wang, Chinua; Zhao, Minfu

2008-11-01

We present the experimental results of a novel single-ended reflecting surface plasma resonance (SPR) based long period fiber grating (LPFG) sensor. A long period fiber grating sensing device is properly designed and fabricated with a pulsed CO2 laser writing system. Different nm-thick thin metal films are deposited on the fiber cladding and the fiber end facet for the excitation of surface plasma waves (SPWs) and the reflection of the transmission spectrum of the LPFG with doubled interaction between metal-dielectric interfaces of the fiber to enhance the SPW of the all-fiber SPR-LPFG sensing system. Different thin metal films with different thicknesses are investigated. The effect of the excited SPW transmission along the fiber cladding-metal interface with silver and aluminum films is observed. It is found that different thicknesses of the metal overlay show different resonant behaviors in terms of resonance peak situation, bandwidth and energy loss. Within a certain range, thinner metal film shows narrower bandwidth and deeper peak loss.

Accuracy optimization with wavelength tunability in overlay imaging technology

NASA Astrophysics Data System (ADS)

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.

Evaluating diffraction based overlay metrology for double patterning technologies

NASA Astrophysics Data System (ADS)

Saravanan, Chandra Saru; Liu, Yongdong; Dasari, Prasad; Kritsun, Oleg; Volkman, Catherine; Acheta, Alden; La Fontaine, Bruno

2008-03-01

Demanding sub-45 nm node lithographic methodologies such as double patterning (DPT) pose significant challenges for overlay metrology. In this paper, we investigate scatterometry methods as an alternative approach to meet these stringent new metrology requirements. We used a spectroscopic diffraction-based overlay (DBO) measurement technique in which registration errors are extracted from specially designed diffraction targets for double patterning. The results of overlay measurements are compared to traditional bar-in-bar targets. A comparison between DBO measurements and CD-SEM measurements is done to show the correlation between the two approaches. We discuss the total measurement uncertainty (TMU) requirements for sub-45 nm nodes and compare TMU from the different overlay approaches.

Predicting the accuracy of ligand overlay methods with Random Forest models.

PubMed

Nandigam, Ravi K; Evans, David A; Erickson, Jon A; Kim, Sangtae; Sutherland, Jeffrey J

2008-12-01

The accuracy of binding mode prediction using standard molecular overlay methods (ROCS, FlexS, Phase, and FieldCompare) is studied. Previous work has shown that simple decision tree modeling can be used to improve accuracy by selection of the best overlay template. This concept is extended to the use of Random Forest (RF) modeling for template and algorithm selection. An extensive data set of 815 ligand-bound X-ray structures representing 5 gene families was used for generating ca. 70,000 overlays using four programs. RF models, trained using standard measures of ligand and protein similarity and Lipinski-related descriptors, are used for automatically selecting the reference ligand and overlay method maximizing the probability of reproducing the overlay deduced from X-ray structures (i.e., using rmsd < or = 2 A as the criteria for success). RF model scores are highly predictive of overlay accuracy, and their use in template and method selection produces correct overlays in 57% of cases for 349 overlay ligands not used for training RF models. The inclusion in the models of protein sequence similarity enables the use of templates bound to related protein structures, yielding useful results even for proteins having no available X-ray structures.

Overlay improvements using a real time machine learning algorithm

NASA Astrophysics Data System (ADS)

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.

Improving concrete overlay construction.

DOT National Transportation Integrated Search

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, ...

Type A polymer concrete overlay field trials : final report.

DOT National Transportation Integrated Search

1984-12-01

This report describes placement and subsequent performance of two methyl methacrylate polymer concrete overlays. Performance is evaluated as to: 1) the mixing and placement characteristics of the methyl methacrylate polymer concretes as overlay mater...

Wafer edge overlay control solution for N7 and beyond

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Bituminous concrete overlay studies.

DOT National Transportation Integrated Search

1971-01-01

Deflection tests conducted on eight sections of primary highway, both before and after asphaltic concrete resurfacings, were analyzed as a study of the utility of such tests in the design of overlays. The application of tentative traffic and allowabl...

Premixed polymer concrete overlays.

DOT National Transportation Integrated Search

1990-01-01

The results of a study undertaken to evaluate premixed polymer concrete overlays (PMPCO) over a 3-year period are presented. The PMPCO evaluated were constructed with polyester amide para resin and silica sand 1;. polyester styrene resin 1 and silica...

High-volume manufacturing device overlay process control

NASA Astrophysics Data System (ADS)

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.

Factors affecting maintenance overlay ride quality : 1996 rideability status.

DOT National Transportation Integrated Search

1997-01-01

In early 1996, the Virginia Transportation Research Council initiated a formal analysis of the factors affecting overlay ride quality. As part of that effort, a statewide, multi-year survey of the ride quality for both new overlays and pavement await...

Microsilica modified concrete for bridge deck overlays : construction report.

DOT National Transportation Integrated Search

1990-10-01

The study objective was to see if microsilica concrete (MC) is a viable alternative to the latex modified concrete (LMC) usually used on bridge deck overlays in Oregon. The study addresses MC overlays placed in 1989 on Portland cement concrete (PCC) ...

Understanding overlay signatures using machine learning on non-lithography context information

NASA Astrophysics Data System (ADS)

Overcast, Marshall; Mellegaard, Corey; Daniel, David; Habets, Boris; Erley, Georg; Guhlemann, Steffen; Thrun, Xaver; Buhl, Stefan; Tottewitz, Steven

2018-03-01

Overlay errors between two layers can be caused by non-lithography processes. While these errors can be compensated by the run-to-run system, such process and tool signatures are not always stable. In order to monitor the impact of non-lithography context on overlay at regular intervals, a systematic approach is needed. Using various machine learning techniques, significant context parameters that relate to deviating overlay signatures are automatically identified. Once the most influential context parameters are found, a run-to-run simulation is performed to see how much improvement can be obtained. The resulting analysis shows good potential for reducing the influence of hidden context parameters on overlay performance. Non-lithographic contexts are significant contributors, and their automatic detection and classification will enable the overlay roadmap, given the corresponding control capabilities.

Unique method for controlling device level overlay with high-NA optical overlay technique using YieldStar in a DRAM HVM environment

NASA Astrophysics Data System (ADS)

Park, Dong-Kiu; Kim, Hyun-Sok; Seo, Moo-Young; Ju, Jae-Wuk; Kim, Young-Sik; Shahrjerdy, Mir; van Leest, Arno; Soco, Aileen; Miceli, Giacomo; Massier, Jennifer; McNamara, Elliott; Hinnen, Paul; Böcker, Paul; Oh, Nang-Lyeom; Jung, Sang-Hoon; Chai, Yvon; Lee, Jun-Hyung

2018-03-01

This paper demonstrates the improvement using the YieldStar S-1250D small spot, high-NA, after-etch overlay in-device measurements in a DRAM HVM environment. It will be demonstrated that In-device metrology (IDM) captures after-etch device fingerprints more accurately compared to the industry-standard CDSEM. Also, IDM measurements (acquiring both CD and overlay) can be executed significantly faster increasing the wafer sampling density that is possible within a realistic metrology budget. The improvements to both speed and accuracy open the possibility of extended modeling and correction capabilities for control. The proof-book data of this paper shows a 36% improvement of device overlay after switching to control in a DRAM HVM environment using indevice metrology.

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

NASA Astrophysics Data System (ADS)

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.

Reducing the overlay metrology sensitivity to perturbations of the measurement stack

NASA Astrophysics Data System (ADS)

Zhou, Yue; Park, DeNeil; Gutjahr, Karsten; Gottipati, Abhishek; Vuong, Tam; Bae, Sung Yong; Stokes, Nicholas; Jiang, Aiqin; Hsu, Po Ya; O'Mahony, Mark; Donini, Andrea; Visser, Bart; de Ruiter, Chris; Grzela, Grzegorz; van der Laan, Hans; Jak, Martin; Izikson, Pavel; Morgan, Stephen

2017-03-01

Overlay metrology setup today faces a continuously changing landscape of process steps. During Diffraction Based Overlay (DBO) metrology setup, many different metrology target designs are evaluated in order to cover the full process window. The standard method for overlay metrology setup consists of single-wafer optimization in which the performance of all available metrology targets is evaluated. Without the availability of external reference data or multiwafer measurements it is hard to predict the metrology accuracy and robustness against process variations which naturally occur from wafer-to-wafer and lot-to-lot. In this paper, the capabilities of the Holistic Metrology Qualification (HMQ) setup flow are outlined, in particular with respect to overlay metrology accuracy and process robustness. The significance of robustness and its impact on overlay measurements is discussed using multiple examples. Measurement differences caused by slight stack variations across the target area, called grating imbalance, are shown to cause significant errors in the overlay calculation in case the recipe and target have not been selected properly. To this point, an overlay sensitivity check on perturbations of the measurement stack is presented for improvement of the overlay metrology setup flow. An extensive analysis on Key Performance Indicators (KPIs) from HMQ recipe optimization is performed on µDBO measurements of product wafers. The key parameters describing the sensitivity to perturbations of the measurement stack are based on an intra-target analysis. Using advanced image analysis, which is only possible for image plane detection of μDBO instead of pupil plane detection of DBO, the process robustness performance of a recipe can be determined. Intra-target analysis can be applied for a wide range of applications, independent of layers and devices.

Assessment and prediction of drying shrinkage cracking in bonded mortar overlays

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 wasmore » 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.« less

On Adding Structure to Unstructured Overlay Networks

NASA Astrophysics Data System (ADS)

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.

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

PubMed

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.

Achieving optimum diffraction based overlay performance

NASA Astrophysics Data System (ADS)

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.

Cracking and debonding of a thin fiber reinforced concrete overlay.

DOT National Transportation Integrated Search

2017-04-01

Previous field studies suggested that macro-fibers incorporated in thin overlay pavements will result in reduced crack opening widths, vertical deflections, and debonding rates compared to that of unreinforced overlays. A simple finite element (FE) m...

KML Super Overlay to WMS Translator

NASA Technical Reports Server (NTRS)

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.

Longer Lasting Bridge Deck Overlays

DOT National Transportation Integrated Search

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...

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

NASA Astrophysics Data System (ADS)

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.

Structural analyses of a rigid pavement overlaying a sub-surface void

NASA Astrophysics Data System (ADS)

Adam, Fatih Alperen

Pavement failures are very hazardous for public safety and serviceability. These failures in pavements are mainly caused by subsurface voids, cracks, and undulation at the slab-base interface. On the other hand, current structural analysis procedures for rigid pavement assume that the slab-base interface is perfectly planar and no imperfections exist in the sub-surface soil. This assumption would be violated if severe erosion were to occur due to inadequate drainage, thermal movements, and/or mechanical loading. Until now, the effect of erosion was only considered in the faulting performance model, but not with regards to transverse cracking at the mid-slab edge. In this research, the bottom up fatigue cracking potential, caused by the combined effects of wheel loading and a localized imperfection in the form of a void below the mid-slab edge, is studied. A robust stress and surface deflection analysis was also conducted to evaluate the influence of a sub-surface void on layer moduli back-calculation. Rehabilitative measures were considered, which included a study on overlay and fill remediation. A series regression of equations was proposed that provides a relationship between void size, layer moduli stiffness, and the overlay thickness required to reduce the stress to its original pre-void level. The effect of the void on 3D pavement crack propagation was also studied under a single axle load. The amplifications to the stress intensity was shown to be high but could be mitigated substantially if stiff material is used to fill the void and impede crack growth. The pavement system was modeled using the commercial finite element modeling program Abaqus RTM. More than 10,000 runs were executed to do the following analysis: stress analysis of subsurface voids, E-moduli back-calculation of base layer, pavement damage calculations of Beaumont, TX, overlay thickness estimations, and mode I crack analysis. The results indicate that the stress and stress intensity are, on

Study of correlation between overlay and displacement measured by Coherent Gradient Sensing (CGS) interferometry

NASA Astrophysics Data System (ADS)

Mileham, Jeffrey; Tanaka, Yasushi; Anberg, Doug; Owen, David M.; Lee, Byoung-Ho; Bouche, Eric

2016-03-01

Within the semiconductor lithographic process, alignment control is one of the most critical considerations. In order to realize high device performance, semiconductor technology is approaching the 10 nm design rule, which requires progressively smaller overlay budgets. Simultaneously, structures are expanding in the 3rd dimension, thereby increasing the potential for inter-layer distortion. For these reasons, device patterning is becoming increasingly difficult as the portion of the overlay budget attributed to process-induced variation increases. After lithography, overlay gives valuable feedback to the lithography tool; however overlay measurements typically have limited density, especially at the wafer edge, due to throughput considerations. Moreover, since overlay is measured after lithography, it can only react to, but not predict the process-induced overlay. This study is a joint investigation in a high-volume manufacturing environment of the portion of overlay associated with displacement induced by a single process across many chambers. Displacement measurements are measured by Coherent Gradient Sensing (CGS) interferometry, which generates high-density displacement maps (>3 million points on a 300 mm wafer) such that the stresses induced die-by-die and process-by-process can be tracked in detail. The results indicate the relationship between displacement and overlay shows the ability to forecast overlay values before the lithographic process. Details of the correlation including overlay/displacement range, and lot-to-lot displacement variability are considered.

Process effects resulting from an increased BARC thickness

NASA Astrophysics Data System (ADS)

Eakin, Ronald J.; Detweiler, Shangting F.; Stagaman, Gregory J.; Tesauro, Mark R.; Spak, Mark A.; Dammel, Ralph R.

1997-07-01

Process improvements attributed to the use of bottom anti- reflective coatings (B.A.R.C.s) are well documented. As our experience with these materials improves, so does our understanding of additional optimization. Recent supplier experiments suggest an increase in the thickness of AZR BARLiTM (bottom anti-reflective layer i-line) solution to reduce photoresist swing curve ratios. Also, changes in thin film stack on common substrates can adversely affect the degree of photoresist reflective notching. It is therefore of extreme importance to determine optimum thickness(es) of a B.A.R.C. material to ensure maximum process potential. We document several process effects in the conversion of a SRAM test device (0.38 - 0.45 micrometers) from a 650 angstrom to a 2000 angstrom BARLiTM film thickness using conventional i-line photolithography. Critical dimension (CD) uniformity and depth of focus (DOF) are evaluated. Defect density between the two processes are compared before and after etch employing optical metrology and electrical test structures. Sensitivity of overlay as a function of BARLiTM film thickness is investigated as well.

Evaluation of the construction and performance of multiple layer polymer concrete overlays : interim report no. 2, condition of the overlays after five years in service.

DOT National Transportation Integrated Search

1987-01-01

This interim report presents the results after 5 years of a study undertaken to evaluate multiple layer polymer concrete overlays over a 10-year period. The report indicates that an overlay of low permeability and high skid resistance can be successf...

Flexible pavement overlay design procedures. Volume 2: User manual

NASA Astrophysics Data System (ADS)

Majidzadeh, K.; Ilves, G. J.

1981-08-01

This user manual outlines a procedure for the design of asphaltic concrete overlays on existing asphaltic concrete pavement surfaces. It is intended as a guide to the user on the type and form of information required as input to the procedure and contains all elements necessary for the user to prepare designs for flexible pavement overlays.

Performance evaluation of bridges with structural bridge deck overlays (SBDO).

DOT National Transportation Integrated Search

2006-03-01

Structural Bridge Deck Overlay (SBDO) involves applying 6 to 10 inches (150 to 200 mm) of normal weight, class AA, reinforced concrete directly to a bridges original slab. The overlay is designed to increase the deck elevation to an extent that st...

Direct Mask Overlay Inspection

NASA Astrophysics Data System (ADS)

Hsia, Liang-Choo; Su, Lo-Soun

1983-11-01

In this paper, we present a mask inspection methodology and procedure that involves direct X-Y measurements. A group of dice is selected for overlay measurement; four measurement targets were laid out in the kerf of each die. The measured coordinates are then fit-ted to either a "historical" grid, which reflects the individual tool bias, or to an ideal grid squares fashion. Measurements are done using a Nikon X-Y laser interferometric measurement system, which provides a reference grid. The stability of the measurement system is essential. We then apply appropriate statistics to the residual after the fit to determine the overlay performance. Statistical methods play an important role in the product disposition. The acceptance criterion is, however, a compromise between the cost for mask making and the final device yield. In order to satisfy the demand on mask houses for quality of masks and high volume, mixing lithographic tools in mask making has become more popular, in particular, mixing optical and E-beam tools. In this paper, we also discuss the inspection procedure for mixing different lithographic tools.

Explaining the mechanisms through which regional atmospheric circulation variability drives summer temperatures and glacial melt in western High Mountain Asia (HMA)

NASA Astrophysics Data System (ADS)

Forsythe, Nathan; Fowler, Hayley; Blenkinsop, Stephen; Li, Xiaofeng; Pritchard, David

2017-04-01

Comprehension of mechanisms by which atmospheric circulation influences sub-regional temperature and water resources variability in high-elevation mountainous catchments is of great scientific urgency due to the dependency of large downstream populations on the river flows these basins provide. In this work we quantify a regional atmospheric pattern, the Karakoram Zonal Shear (KZS), with a very pronounced annual cycle which we standardise into a dimensionless (seasonal) circulation metric the Karakoram Zonal Index (KZI). Going beyond previous regional circulation metrics such as the "middle-upper tropospheric temperature index" (MUTTI) or the Webster and Yang Monsoonal Index (WYMI) which have focused solely on the South Asian Summer Monsoon (June to September) season, the KZS/KZI provides an indicator which captures the influence and interactions of the westerly jet throughout the entire annual cycle. Use of the KZS and KZI have led us to identify a further regional atmospheric system, the Karakoram Vortex, which propagates "warm high" (anticyclonic postitive temperature anomaly) and "cold low" (cyclonic negative temperature anomaly) patterns across a very broad swath of Central and South Asia in winter but over a much more constrained area of western HMA in summer. The KV exerts this temperature influence through a combination of adiabatic effects and large-scale advection. Quantify KV influence, the KZI shows strong and statistically significantly near surface (2m) air temperatures both across western HMA both as observed through local meteorological stations and as estimated by an ensemble of global meteorological reanalyses. We show that this strong influence on temperature translates to important consequences for meltwater generation from highly glaciated Indus river tributaries which is logical given that previous studies have established the role of air temperature in modulating glacially-derived river flows in western HMA. By improving the understanding of

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

NASA Astrophysics Data System (ADS)

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.

Three projects using 4.75 mm. superpave HMA on Route1A, Route 2A, & Route 27.

DOT National Transportation Integrated Search

2012-04-01

In July & August, 2010, MaineDOT applied 4.75 mm. (5/8 inch) Superpave designed hot mix asphalt : overlays in three locations. These overlay projects were on Route 1A, 2A, and 27, located in Forkstown, : New Portland, and Limestone, respectively. Pro...

Platinum and Palladium Overlayers Dramatically Enhance the Activity of Ruthenium Nanotubes for Alkaline Hydrogen Oxidation

DOE PAGES

St. John, Samuel; Atkinson, Robert W.; Unocic, Kinga A.; ...

2015-10-18

Templated vapor synthesis and thermal annealing were used to synthesize unsupported metallic Ru nanotubes with Pt or Pd overlayers. By controlling the elemental composition and thickness of these overlayers, we obtain nanostructures with very high alkaline hydrogen oxidation activity. For nanotubes with a nominal atomic composition of Ru 0.90Pt 0.10 display a surface-specific activity (2.4 mA/cm 2) that is 35 times greater than that of pure Ru nanotubes at a 50 mV overpotential and 2.5 times greater than that of pure Pt nanotubes (0.98 mA/cm 2). The surface-segregated structure also confers dramatically increased Pt utilization efficiency. We find a platinum-mass-specificmore » activity of 1240 A/gPt for the optimized nanotube versus 280 A/gPt for carbon-supported Pt nanoparticles and 109 A/gPt for monometallic Pt nanotubes. Here, we attribute the enhancement of both area- and platinum-mass-specific activity to the atomic-scale homeomorphism of the nanotube form factor with adlayer-modified polycrystals. Subsurface ligand and bifunctional effects previously observed on segregated, adlayer-modified polycrystals are translated to nanoscale catalysts.« less

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

DOT National Transportation Integrated Search

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 ...

Microsilica modified concrete for bridge deck overlays : second-year interim report.

DOT National Transportation Integrated Search

1994-10-01

This report summarizes the performance of microsilica concrete (MC) overlays on seven distressed portland cement concrete bridge decks at three sites in Oregon. This report emphasizes the overlays' condition after two, or in some cases, three years o...

Improved control of multi-layer overlay in advanced 8nm logic nodes

NASA Astrophysics Data System (ADS)

Kim, Tae-Sun; Park, Young-Sik; Kim, Yong-Chul; Kim, Byoung-Hoon; Lee, Ji-Hun; Kwak, Min-Keun; Choi, Sung-Won; Park, Joon-Soo; Yang, Hong-Cheon; Meixner, Philipp; Lee, Dong-jin; Kwon, Oh-Sung; Kim, Hyun-Su; Park, Jin-Tae; Lee, Sung-Min; Grouwstra, Cedric; van der Meijden, Vidar; El Kodadi, Mohamed; Kim, Chris; Guittet, Pierre-Yves; Nooitgedagt, Tjitte

2018-03-01

With the increase of litho-etch steps the industry requires metrology to deliver solutions to improve throughput of overlay measurements without impacting accuracy. ASML's YieldStar 350E is capable of utilizing targets, which can measure the overlay of multiple layers simultaneously. For the work discussed in this paper, an evaluation is performed on Logic product wafers using both single-layer and multi-layer (MLT) quad type targets (able to capture up to four litho-etch steps). Different target types were compared in terms of Move-and-Acquire (MA) time, residual and matching to SEM. Using the MLT targets, an MA time improvement of 56% was demonstrated on the singlelayer. The maximum delta between the overlay residual among the YieldStar targets after applying an high order model was shown to be 0.05 nm. In comparison to after-etch overlay, the correlation of the MLT target was determined with an R2 > 0.95 using a set-get wafer with induced 10 nm overlay range. On a normal production wafer, the correlation was R2 > 0.67, which is high on a wafer without induced overlay. The comparison of modeling parameters between SEM and MLT targets shows a good match (< 0.16nm) as well.

Effects of concrete moisture on polymer overlay bond over new concrete.

DOT National Transportation Integrated Search

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...

Microsilica modified concrete for bridge deck overlays : first-year interim report.

DOT National Transportation Integrated Search

1991-11-01

The study objective was to see if microsilica concrete (MC) is a viable alternative to the latex modified concrete (LMC) usually used on bridge deck overlays in Oregon. The study addresses MC overlays placed in 1989 on 7 portland cement concrete (PCC...

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Vertical electrical impedance evaluation of asphalt overlays on concrete bridge decks

NASA Astrophysics Data System (ADS)

Baxter, Jared S.; Guthrie, W. Spencer; Waters, Tenli; Barton, Jeffrey D.; Mazzeo, Brian A.

2018-04-01

Vertical electrical impedance scanning of concrete bridge decks is a non-destructive method for quantifying the degree of protection provided to steel reinforcement against the ingress of corrosive agents. Four concrete bridge decks with asphalt overlays in northern Utah were evaluated using scanning vertical electrical impedance measurements in this study. At the time of testing, the bridges ranged in age from 21 to 34 years, and asphalt overlays had been in place for 7 to 22 years, depending on the bridge. Electrical impedance measurements were collected using a previously constructed apparatus that consisted of six probes spanning a transverse distance of 12 ft. The impedance measurements were compared to surface cracking observations and cores obtained from the same four bridge decks. The results presented in this paper demonstrate the utility of scanning vertical electrical impedance measurements for detecting cracks in asphalt overlays and quantifying their severity. In addition, the results demonstrate the sensitivity of impedance measurements to the presence of an intact membrane beneath the asphalt overlay.

Study of μDBO overlay target size reduction for application broadening

NASA Astrophysics Data System (ADS)

Calado, Victor; Dépré, Jérôme; Massacrier, Clément; Tarabrin, Sergey; van Haren, Richard; Dettoni, Florent; Bouyssou, Régis; Dezauzier, Christophe

2018-03-01

With these proceedings we present μ-diffraction-based overlay (μDBO) targets that are well below the currently supported minimum size of 10×10 μm2 . We have been capable of measuring overlay targets as small as 4×4 μm2 with our latest generation YieldStar system. Furthermore we find an excellent precision (TMU < 0.33 nm for 6 × 6 μm2 ) without any compromise on throughput (MAM time < 60 ms). At last a study that compares four generations of YieldStar systems show clearly that the latest generation YieldStar systems is much better capable of reading small overlay targets such that the performance of a 16 × 16 μm2 on an early generation YieldStar 2nd-gen is comparable to that of a 8 × 8 μm2 on the latest YieldStar 5th-gen. This work enables a smaller metrology footprint, more placement flexibility and in-die overlay metrology solutions.

SEM-based overlay measurement between via patterns and buried M1 patterns using high-voltage SEM

NASA Astrophysics Data System (ADS)

Hasumi, Kazuhisa; Inoue, Osamu; Okagawa, Yutaka; Shao, Chuanyu; Leray, Philippe; Halder, Sandip; Lorusso, Gian; Jehoul, Christiane

2017-03-01

The miniaturization of semiconductors continues, importance of overlay measurement is increasing. We measured overlay with analysis SEM called Miracle Eye which can output ultrahigh acceleration voltage in 1998. Meanwhile, since 2006, we have been working on SEM based overlay measurement and developed overlay measurement function of the same layer using CD-SEM. Then, we evaluated overlay of the same layer pattern after etching. This time, in order to measure overlay after lithography, we evaluated the see-through overlay using high voltage SEM CV5000 released in October 2016. In collaboration between imec and Hitachi High-Technologies, we evaluated repeatability, TIS of SEM-OVL as well as correlation between SEM-OVL and Opt-OVL in the M1@ADI and V0@ADI process. Repeatability and TIS results are reasonable and SEM-OVL has good correlation with Opt-OVL. By overlay measurement using CV 5000, we got the following conclusions. (1)SEM_OVL results of both M1 and V0 at ADI show good correlation to OPT_OVL. (2)High voltage SEM can prove the measurement capability of a small pattern(Less than 1 2um) like device that can be placed in-die area. (3)"In-die SEM based overlay" shows possibility for high order control of scanner

Application of overlay modeling and control with Zernike polynomials in an HVM environment

NASA Astrophysics Data System (ADS)

Ju, JaeWuk; Kim, MinGyu; Lee, JuHan; Nabeth, Jeremy; Jeon, Sanghuck; Heo, Hoyoung; Robinson, John C.; Pierson, Bill

2016-03-01

Shrinking technology nodes and smaller process margins require improved photolithography overlay control. Generally, overlay measurement results are modeled with Cartesian polynomial functions for both intra-field and inter-field models and the model coefficients are sent to an advanced process control (APC) system operating in an XY Cartesian basis. Dampened overlay corrections, typically via exponentially or linearly weighted moving average in time, are then retrieved from the APC system to apply on the scanner in XY Cartesian form for subsequent lot exposure. The goal of the above method is to process lots with corrections that target the least possible overlay misregistration in steady state as well as in change point situations. In this study, we model overlay errors on product using Zernike polynomials with same fitting capability as the process of reference (POR) to represent the wafer-level terms, and use the standard Cartesian polynomials to represent the field-level terms. APC calculations for wafer-level correction are performed in Zernike basis while field-level calculations use standard XY Cartesian basis. Finally, weighted wafer-level correction terms are converted to XY Cartesian space in order to be applied on the scanner, along with field-level corrections, for future wafer exposures. Since Zernike polynomials have the property of being orthogonal in the unit disk we are able to reduce the amount of collinearity between terms and improve overlay stability. Our real time Zernike modeling and feedback evaluation was performed on a 20-lot dataset in a high volume manufacturing (HVM) environment. The measured on-product results were compared to POR and showed a 7% reduction in overlay variation including a 22% terms variation. This led to an on-product raw overlay Mean + 3Sigma X&Y improvement of 5% and resulted in 0.1% yield improvement.

Hot cracking susceptibility of Alloy 52M weld overlays onto CF8 stainless steel

NASA Astrophysics Data System (ADS)

Chu, H. A.; Young, M. C.; Chu, H. C.; Tsay, L. W.; Chen, C.

2013-02-01

In this study, weld overlays of Alloy 52M (a nickel-based filler metal) onto CF8 stainless steel (SS) were performed using the gas tungsten arc welding process. Hot cracking in the weld overlays was observed particularly near the interfacial region of the Alloy 52M/CF8 weld overlay. In general, the hot cracks were most likely to occur at the sites with high dilution rates, e.g., at the weld start/end locations of a single pass or in the first and second passes in multi-pass overlays. The region near the weld interface between Alloy 52M and the CF8 SS had a higher hot cracking tendency than the other regions. It was found that the dilution rate and the formation of eutectic-type constituents (i.e., γ/NbC) both played significant roles in the determination of the hot cracking susceptibility of these weld overlays. Nevertheless, hot cracks were entirely eliminated by proper deposition of a SS buffer layer prior to overlaying with Alloy 52M.

Bonded concrete overlay performance in Illinois

DOT National Transportation Integrated Search

2002-04-01

Two bonded concrete overlay rehabilitation projects were constructed in Illinois during the 1990's. The first project was constructed in 1994 and 1995 on Interstate 80, east of Moline. The second project was constructed in 1996 on Interstate 88 near ...

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed Central

Gu, Weidong; Zhang, Xinchang; Gong, Bin; Zhang, Wei; Wang, Lu

2015-01-01

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. PMID:26562152

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

PubMed

Gu, Weidong; Zhang, Xinchang; Gong, Bin; Zhang, Wei; Wang, Lu

2015-01-01

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.

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

PubMed

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.

Sol-Gel-Based Titania-Silica Thin Film Overlay for Long Period Fiber Grating-Based Biosensors.

PubMed

Chiavaioli, Francesco; Biswas, Palas; Trono, Cosimo; Jana, Sunirmal; Bandyopadhyay, Somnath; Basumallick, Nandini; Giannetti, Ambra; Tombelli, Sara; Bera, Susanta; Mallick, Aparajita; Baldini, Francesco

2015-12-15

An evanescent wave optical fiber biosensor based on titania-silica-coated long period grating (LPG) is presented. The chemical overlay, which increases the refractive index (RI) sensitivity of the sensor, consists of a sol-gel-based titania-silica thin film, deposited along the sensing portion of the fiber by means of the dip-coating technique. Changing both the sol viscosity and the withdrawal speed during the dip-coating made it possible to adjust the thickness of the film overlay, which is a crucial parameter for the sensor performance. After the functionalization of the fiber surface using a methacrylic acid/methacrylate copolymer, an antibody/antigen (IgG/anti-IgG) assay was carried out to assess the performance of sol-gel based titania-silica-coated LPGs as biosensors. The analyte concentration was determined from the wavelength shift at the end of the binding process and from the initial binding rate. This is the first time that a sol-gel based titania-silica-coated LPG is proposed as an effective and feasible label-free biosensor. The specificity of the sensor was validated by performing the same model assay after spiking anti-IgG into human serum. With this structured LPG, detection limits of the order of tens of micrograms per liter (10(-11) M) are attained.

Development of an improved overlay procedure for Oregon : volume III, field manual.

DOT National Transportation Integrated Search

1987-12-01

This report is the third in a three-volume series dealing with the development of an improved overlay design procedure for Oregon. This report presents technical guidelines for using the proposed overlay design procedure. Four areas are described, in...

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

NASA Astrophysics Data System (ADS)

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

Catalytic activity and stability of nanometic Rh overlayers prepared by pulsed arc-plasma deposition and r.f. magnetron-sputtering

NASA Astrophysics Data System (ADS)

Misumi, Satoshi; Matsumoto, Akinori; Yoshida, Hiroshi; Sato, Tetsuya; Machida, Masato

2018-01-01

50 μm-thick Fe-Cr-Al metal foils covered by 7 nm-thick Rh overlayers were prepared by pulsed arc-plasma (AP) and r.f. magnetron sputtering technique to compare their catalytic activities. As-prepared metal foil catalysts were wrapped into a honeycomb structure with a density of 900 cells per square inches and the stoichiometric NO-CO-C3H6-O2 reaction was performed at space velocity of 1.2 × 105 h-1. During temperature ramp at 10 °C min-1, honeycomb catalysts showed steep light-off of NO, CO, and C3H6 at above 200 °C and their conversions soon reached to almost 100%. Both catalysts exhibited high turnover frequencies close to or more than 50-fold greater compared with those for a reference Rh/ZrO2 powder-coated cordierite honeycomb prepared using a conventional slurry coating. When the temperature ramping was repeated, however, the catalytic activity was decreased to the different extent depending on the preparation procedure. Significant deactivation occurred only when prepared by sputtering, whereas the sample prepared by AP showed no signs of deactivation. The deactivation is associated with the formation of passivation layers consisting of Fe, Cr, and Al oxides, which covered the surface and decreased the surface concentration of Rh. The Rh overlayer formed by AP was found to be thermally stable because of the strong adhesion to the metal foil surface, compared to the sample prepared by sputtering.

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

DOT National Transportation Integrated Search

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 ...

Evaluation of hydraulic cement concrete overlays placed on three pavements in Virginia.

DOT National Transportation Integrated Search

2000-08-01

Three hydraulic cement concrete pavement overlays were placed in the summer of 1995 at three locations in Virginia. Two of the overlays were placed on continuously reinforced concrete pavement to prevent spalling caused by a shy cover over the reinfo...

Intra-field on-product overlay improvement by application of RegC and TWINSCAN corrections

NASA Astrophysics Data System (ADS)

Sharoni, Ofir; Dmitriev, Vladimir; Graitzer, Erez; Perets, Yuval; Gorhad, Kujan; van Haren, Richard; Cekli, Hakki E.; Mulkens, Jan

2015-03-01

The on product overlay specification and Advanced Process Control (APC) is getting extremely challenging particularly after the introduction of multi-patterning applications like Spacer Assisted Double Patterning (SADP) and multipatterning techniques like N-repetitive Litho-Etch steps (LEN, N >= 2). When the latter is considered, most of the intrafield overlay contributors drop out of the overlay budget. This is a direct consequence of the fact that the scanner settings (like dose, illumination settings, etc.) as well as the subsequent processing steps can be made very similar for two consecutive Litho-Etch layers. The major overlay contributor that may require additional attention is the Image Placement Error (IPE). When the inter-layer overlay is considered, controlling the intra-field overlay contribution gets more complicated. In addition to the IPE contribution, the TWINSCANTM lens fingerprint in combination with the exposure settings is going to play a role as well. Generally speaking, two subsequent functional layers have different exposure settings. This results in a (non-reticle) additional overlay contribution. In this paper, we have studied the wafer overlay correction capability by RegC® in addition to the TWINSCANTM intrafield corrections to improve the on product overlay performance. RegC® is a reticle intra-volume laser writing technique that causes a predictable deformation element (RegC® deformation element) inside the quartz (Qz) material of a reticle. This technique enables to post-process an existing reticle to correct for instance for IPE. Alternatively, a pre-determined intra-field fingerprint can be added to the reticle such that it results in a straight field after exposure. This second application might be very powerful to correct for instance for (cold) lens fingerprints that cannot be corrected by the scanner itself. Another possible application is the intra-field processing fingerprint. One should realize that a RegC® treatment of a

The use of fiber reinforcement in latex modified concrete overlay : final report.

DOT National Transportation Integrated Search

2016-12-01

The requirement to quickly reopen highways in North Carolina has motivated the increased use of rapid-setting concrete in overlays. The addition of polymer latex to the material has been used to increase the service life of the overlays. The latex mo...

Thin Bonded Concrete Overlay and Bonding Agents

DOT National Transportation Integrated Search

1996-06-01

This report presents the construction procedures and initial performance evaluation of a four-inch Bonded Concrete Overlay placed on Interstate 80 near Moline, Illinois. Preconstruction testing consisted of Falling Weight Deflectometer, permeability ...

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

NASA Astrophysics Data System (ADS)

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.

Repair, Evaluation, Maintenance, and Rehabilitation Research Program Overlays on Horizontal Concrete Surfaces: Case Histories

DTIC Science & Technology

1994-02-01

ash, silica-fume, polymer -modified, polymer , and fiber - reinforced concretes. For some nonstructural repairs, unbonded overlays have been employed in an...which silica fume was included; polymer -modified concrete overlay, one in which a polymer admixture had been included; and fiber - reinforced concrete...of pumps. However, a determination has not been made for the source of leakage. 56 Chapter 6 Polymer -Modified Concrete Overlays 7 Fiber - Reinforced

Research notes : polymer concrete bridge deck overlays : Deschutes River Bridge (Biggs), Maupin Bridge (Maupin) : final report.

DOT National Transportation Integrated Search

1995-07-01

This report documents the construction and performance of two thin polymer concrete (with polyester/styrene resins) bridge deck overlays. The overlays were constructed in Biggs and Maupin, Oregon in June 1993. Construction of the overlays was less th...

Overlay Tolerances For VLSI Using Wafer Steppers

NASA Astrophysics Data System (ADS)

Levinson, Harry J.; Rice, Rory

1988-01-01

In order for VLSI circuits to function properly, the masking layers used in the fabrication of those devices must overlay each other to within the manufacturing tolerance incorporated in the circuit design. The capabilities of the alignment tools used in the masking process determine the overlay tolerances to which circuits can be designed. It is therefore of considerable importance that these capabilities be well characterized. Underestimation of the overlay accuracy results in unnecessarily large devices, resulting in poor utilization of wafer area and possible degradation of device performance. Overestimation will result in significant yield loss because of the failure to conform to the tolerances of the design rules. The proper methodology for determining the overlay capabilities of wafer steppers, the most commonly used alignment tool for the production of VLSI circuits, is the subject of this paper. Because cost-effective manufacturing process technology has been the driving force of VLSI, the impact on productivity is a primary consideration in all discussions. Manufacturers of alignment tools advertise the capabilities of their equipment. It is notable that no manufacturer currently characterizes his aligners in a manner consistent with the requirements of producing very large integrated circuits, as will be discussed. This has resulted in the situation in which the evaluation and comparison of the capabilities of alignment tools require the attention of a lithography specialist. Unfortunately, lithographic capabilities must be known by many other people, particularly the circuit designers and the managers responsible for the financial consequences of the high prices of modern alignment tools. All too frequently, the designer or manager is confronted with contradictory data, one set coming from his lithography specialist, and the other coming from a sales representative of an equipment manufacturer. Since the latter generally attempts to make his

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

NASA Astrophysics Data System (ADS)

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.

Evaluation of the Hamburg Rut Tester and Moisture Induced Stress Test (MIST) for field control of hot mix asphalt (HMA) in Oklahoma : final report.

DOT National Transportation Integrated Search

2013-03-01

This report covers the evaluation of the Hamburg Loaded Wheel Rut Tester (OHD L-55) and the : Moisture Induced Stress Tester (MIST) for field control of Oklahoma HMA mixtures. OHD L-55 : was evaluated as a possible replacement for AASHTO T 283 and fo...

Use of Ground Penetrating Radar at the FAA's National Airport Pavement Test Facility

NASA Astrophysics Data System (ADS)

Injun, Song

2015-04-01

The Federal Aviation Administration (FAA) in the United States has used a ground-coupled Ground Penetrating Radar (GPR) at the National Airport Pavement Test Facility (NAPTF) since 2005. One of the primary objectives of the testing at the facility is to provide full-scale pavement response and failure information for use in airplane landing gear design and configuration studies. During the traffic testing at the facility, a GSSI GPR system was used to develop new procedures for monitoring Hot Mix Asphalt (HMA) pavement density changes that is directly related to pavement failure. After reviewing current setups for data acquisition software and procedures for identifying different pavement layers, dielectric constant and pavement thickness were selected as dominant parameters controlling HMA properties provided by GPR. A new methodology showing HMA density changes in terms of dielectric constant variations, called dielectric sweep test, was developed and applied in full-scale pavement test. The dielectric constant changes were successfully monitored with increasing airplane traffic numbers. The changes were compared to pavement performance data (permanent deformation). The measured dielectric constants based on the known HMA thicknesses were also compared with computed dielectric constants using an equation from ASTM D4748-98 Standard Test Method for Determining the Thickness of Bound Pavement Layers Using Short-Pulse Radar. Six inches diameter cylindrical cores were taken after construction and traffic testing for the HMA layer bulk specific gravity. The measured bulk specific gravity was also compared to monitor HMA density changes caused by aircraft traffic conditions. Additionally this presentation will review the applications of the FAA's ground-coupled GPR on embedded rebar identification in concrete pavement, sewer pipes in soil, and gage identifications in 3D plots.

Guidelines on design and construction of high performance thin HMA overlays.

DOT National Transportation Integrated Search

2016-08-01

Key Components of Mix Design and Material Properties: : High-quality aggregate - SAC A for high : volume roads : - PG 70 or 76 (Polymer Modified binders) : - RAP and RAS (shingles) not allowed : - Minimum binder content ( Over 6%) : - Pay for binder ...

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

NASA Astrophysics Data System (ADS)

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.

Cooperative Resource Pricing in Service Overlay Networks for Mobile Agents

NASA Astrophysics Data System (ADS)

Nakano, Tadashi; Okaie, Yutaka

The success of peer-to-peer overlay networks depends on cooperation among participating peers. In this paper, we investigate the degree of cooperation among individual peers required to induce globally favorable properties in an overlay network. Specifically, we consider a resource pricing problem in a market-oriented overlay network where participating peers sell own resources (e.g., CPU cycles) to earn energy which represents some money or rewards in the network. In the resource pricing model presented in this paper, each peer sets the price for own resource based on the degree of cooperation; non-cooperative peers attempt to maximize their own energy gains, while cooperative peers maximize the sum of own and neighbors' energy gains. Simulation results are presented to demonstrate that the network topology is an important factor influencing the minimum degree of cooperation required to increase the network-wide global energy gain.

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

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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.

Polymer concrete overlay test program : interim report.

DOT National Transportation Integrated Search

1974-11-01

This report describes work done on various combinations of monomers and polymer concrete mixes and identifies the mixes showing the greatest potential for use in bridge deck overlays . Presented are test results showing physical properties of various...

Overlay field application program, Pennsylvania US-119.

DOT National Transportation Integrated Search

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...

Reduction of wafer-edge overlay errors using advanced correction models, optimized for minimal metrology requirements

NASA Astrophysics Data System (ADS)

Kim, Min-Suk; Won, Hwa-Yeon; Jeong, Jong-Mun; Böcker, Paul; Vergaij-Huizer, Lydia; Kupers, Michiel; Jovanović, Milenko; Sochal, Inez; Ryan, Kevin; Sun, Kyu-Tae; Lim, Young-Wan; Byun, Jin-Moo; Kim, Gwang-Gon; Suh, Jung-Joon

2016-03-01

In order to optimize yield in DRAM semiconductor manufacturing for 2x nodes and beyond, the (processing induced) overlay fingerprint towards the edge of the wafer needs to be reduced. Traditionally, this is achieved by acquiring denser overlay metrology at the edge of the wafer, to feed field-by-field corrections. Although field-by-field corrections can be effective in reducing localized overlay errors, the requirement for dense metrology to determine the corrections can become a limiting factor due to a significant increase of metrology time and cost. In this study, a more cost-effective solution has been found in extending the regular correction model with an edge-specific component. This new overlay correction model can be driven by an optimized, sparser sampling especially at the wafer edge area, and also allows for a reduction of noise propagation. Lithography correction potential has been maximized, with significantly less metrology needs. Evaluations have been performed, demonstrating the benefit of edge models in terms of on-product overlay performance, as well as cell based overlay performance based on metrology-to-cell matching improvements. Performance can be increased compared to POR modeling and sampling, which can contribute to (overlay based) yield improvement. Based on advanced modeling including edge components, metrology requirements have been optimized, enabling integrated metrology which drives down overall metrology fab footprint and lithography cycle time.

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

The Assessment of Distortion in Neurosurgical Image Overlay Projection.

PubMed

Vakharia, Nilesh N; Paraskevopoulos, Dimitris; Lang, Jozsef; Vakharia, Vejay N

2016-02-01

Numerous studies have demonstrated the superiority of neuronavigation during neurosurgical procedures compared to non-neuronavigation-based procedures. Limitations to neuronavigation systems include the need for the surgeons to avert their gaze from the surgical field and the cost of the systems, especially for hospitals in developing countries. Overlay projection of imaging directly onto the patient allows localization of intracranial structures. A previous study using overlay projection demonstrated the accuracy of image coregistration for a lesion in the temporal region but did not assess image distortion when projecting onto other anatomical locations. Our aim is to quantify this distortion and establish which regions of the skull would be most suitable for overlay projection. Using the difference in size of a square grid when projected onto an anatomically accurate model skull and a flat surface, from the same distance, we were able to calculate the degree of image distortion when projecting onto the skull from the anterior, posterior, superior, and lateral aspects. Measuring the size of a square when projected onto a flat surface from different distances allowed us to model change in lesion size when projecting a deep structure onto the skull surface. Using 2 mm as the upper limit for distortion, our results show that images can be accurately projected onto the majority (81.4%) of the surface of the skull. Our results support the use of image overlay projection in regions with ≤2 mm distortion to assist with localization of intracranial lesions at a fraction of the cost of existing methods. © The Author(s) 2015.

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

DOT National Transportation Integrated Search

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...

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

DOT National Transportation Integrated Search

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...

A field investigation of concrete overlays containing latex, silica fume, or Pyrament cement.

DOT National Transportation Integrated Search

1996-01-01

This study evaluated latex-modified concretes (LMC) and concretes containing silica fume (SFC) or Pyrament-blended cement (PBCC) in bridge deck overlays in the field. The condition of the overlays was monitored for 4 years. LMC and SFC were placed in...

Optical DC overlay measurement in the 2nd level process of 65 nm alternating phase shift mask

NASA Astrophysics Data System (ADS)

Ma, Jian; Han, Ke; Lee, Kyung; Korobko, Yulia; Silva, Mary; Chavez, Joas; Irvine, Brian; Henrichs, Sven; Chakravorty, Kishore; Olshausen, Robert; Chandramouli, Mahesh; Mammen, Bobby; Padmanaban, Ramaswamy

2005-11-01

Alternating phase shift mask (APSM) techniques help bridge the significant gap between the lithography wavelength and the patterning of minimum features, specifically, the poly line of 35 nm gate length (1x) in Intel's 65 nm technology. One of key steps in making APSM mask is to pattern to within the design tolerances the 2nd level resist so that the zero-phase apertures will be protected by the resist and the pi-phase apertures will be wide open for quartz etch. The ability to align the 2nd level to the 1st level binary pattern, i.e. the 2nd level overlay capability is very important, so is the capability of measuring the overlay accurately. Poor overlay could cause so-called the encroachment after quartz etch, producing undesired quartz bumps in the pi-apertures or quartz pits in the zero-apertures. In this paper, a simple, low-cost optical setup for the 2nd level DC (develop check) overlay measurements in the high volume manufacturing (HVM) of APSM masks is presented. By removing systematic errors in overlay associated with TIS and MIS (tool-induced shift and Mask-process induced shift), it is shown that this setup is capable of supporting the measurement of DC overlay with a tolerance as small as +/- 25 nm. The outstanding issues, such as DC overlay error component analysis, DC - FC (final check) overlay correlation and the overlay linearity (periphery vs. indie), are discussed.

Polymer concrete overlay test program : users' manual.

DOT National Transportation Integrated Search

1977-12-01

The purpose of this manual is to provide the reader with sufficient information to successfully place a polyester styrene polymer concrete overlay on a bridge deck. Although the binder is a resin, no detailed knowledge of polymer chemistry is needed ...

Evaluation of thin overlays for bridge decks.

DOT National Transportation Integrated Search

2010-11-01

Eight thin polymer overlay systems were evaluated in the laboratory and on two bridge decks exposed to trucks and passenger vehicles including those with studded tires. The products were Mark 154, Flex-O-Lith, Safetrack HW, Kwik Bond PPC MLS, Tyregri...

Evaluation of thin overlays for bridge decks.

DOT National Transportation Integrated Search

2009-11-01

Eight thin polymer overlay systems were evaluated in the laboratory and on two bridge decks exposed to trucks and passenger vehicles including those with studded tires. The products were Mark 154, Flex-O-Lith, Safetrack HW, Kwik Bond PPC MLS, Tyregri...

Evaluation of Tizian overlays by means of a swept source optical coherence tomography system

NASA Astrophysics Data System (ADS)

Marcauteanu, Corina; Sinescu, Cosmin; Negrutiu, Meda Lavinia; Stoica, Eniko Tunde; Topala, Florin; Duma, Virgil Florin; Bradu, Adrian; Podoleanu, Adrian Gh.

2016-03-01

The teeth affected by pathologic attrition can be restored by a minimally invasive approach, using Tizian overlays. In this study we prove the advantages of a fast swept source (SS) OCT system in the evaluation of Tizian overlays placed in an environment characterized by high occlusal forces. 12 maxillary first premolars were extracted and prepared for overlays. The Tizian overlays were subjected to 3000 alternating cycles of thermo-cycling (from -10°C to +50°C) and to mechanical occlusal overloads (at 800 N). A fast SS OCT system was used to evaluate the Tizian overlays before and after the mechanical and thermal straining. The SS (Axsun Technologies, Billerica, MA) has a central wavelength of 1060 nm, sweeping range of 106 nm (quoted at 10 dB) and a 100 kHz line rate. The depth resolution of the system, measured experimentally in air was 10 μm. The imaging system used for this study offers high spatial resolutions in both directions, transversal and longitudinal of around 10 μm, a high sensitivity, and it is also able to acquire entire tridimensional (3D)/volume reconstructions as fast as 2.5 s. Once the full dataset was acquired, rendered high resolutions en-face projections could be produced. Using them, the overlay (i.e., cement) abutment tooth interfaces were remarked both on B-scans/two-dimensional (2D) sections and in the 3D reconstructions. Using the system several open interfaces were possible to detect. The fast SS OCT system thus proves useful in the evaluation of zirconia reinforced composite overlays, placed in an environment characterized by high occlusal forces.

Design and construction of a bonded fiber concrete overlay of CRCP : final report.

DOT National Transportation Integrated Search

1992-01-01

The purpose of this study was to evaluate a bonded steel fiber reinforced concrete overlay on an existing 8-inch CRC pavement on Interstate 10 south of Baton Rough, LA. The project objectives were to provide an overlay with a high probability for lon...

Preparation of rumble strips prior to overlayment.

DOT National Transportation Integrated Search

2010-07-01

The use of rumble strips in pavement to reduce run-off-road accidents is relatively new. In New Hampshire, these installations began in the mid to : late 1990s. The New Hampshire Department of Transportation performed its first overlay of rumble stri...

A Preliminary Study of Building a Transmission Overlay for Regional US Power Grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei, Yin; Li, Yalong; Liu, Yilu

2015-01-01

Many European countries have taken steps toward a Supergrid in order to transmit large amount of intermittent and remote renewable energy over long distance to load centers. In the US, as the expected increase in renewable generation and electricity demand, similar problem arises. A potential solution is to upgrade the transmission system at a higher voltage by constructing a new overlay grid. This paper will first address basic requirements for such an overlay grid. Potential transmission technologies will also be discussed. A multi-terminal VSC HVDC model is developed in DSATools to implement the overlay grid and a test case onmore » a regional NPCC system will be simulated. Another test system of entire US power grid, with three different interconnections tied together using back-to-back HVDC, is also introduced in this paper. Building an overlay system on top of this test case is ongoing, and will be discussed in future work.« less

Latex modified Portland cement overlays : an analysis of samples removed from a bridge deck.

DOT National Transportation Integrated Search

1975-01-01

This report describes an evaluation of the latex modified mortar overlay the Route 85 (NBL) bridge over the Roanoke River. While the performance of the overlay has been generally satisfactory, corings and chloride analyses indicate the possibility of...

Two-layer critical dimensions and overlay process window characterization and improvement in full-chip computational lithography

NASA Astrophysics Data System (ADS)

Sturtevant, John L.; Liubich, Vlad; Gupta, Rachit

2016-04-01

Edge placement error (EPE) was a term initially introduced to describe the difference between predicted pattern contour edge and the design target for a single design layer. Strictly speaking, this quantity is not directly measurable in the fab. What is of vital importance is the relative edge placement errors between different design layers, and in the era of multipatterning, the different constituent mask sublayers for a single design layer. The critical dimensions (CD) and overlay between two layers can be measured in the fab, and there has always been a strong emphasis on control of overlay between design layers. The progress in this realm has been remarkable, accelerated in part at least by the proliferation of multipatterning, which reduces the available overlay budget by introducing a coupling of overlay and CD errors for the target layer. Computational lithography makes possible the full-chip assessment of two-layer edge to edge distances and two-layer contact overlap area. We will investigate examples of via-metal model-based analysis of CD and overlay errors. We will investigate both single patterning and double patterning. For single patterning, we show the advantage of contour-to-contour simulation over contour to target simulation, and how the addition of aberrations in the optical models can provide a more realistic CD-overlay process window (PW) for edge placement errors. For double patterning, the interaction of 4-layer CD and overlay errors is very complex, but we illustrate that not only can full-chip verification identify potential two-layer hotspots, the optical proximity correction engine can act to mitigate such hotspots and enlarge the joint CD-overlay PW.

Latex-modified concrete overlay containing Type K cement.

DOT National Transportation Integrated Search

2005-01-01

Hydraulic cement concrete overlays are usually placed on bridges to reduce the infiltration of water and chloride ions and to improve skid resistance, ride quality, and surface appearance. Constructed in accordance with prescription specifications, s...

Advancements of diffraction-based overlay metrology for double patterning

NASA Astrophysics Data System (ADS)

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.

Research notes : geotextile fabrics under asphalt concrete overlays.

DOT National Transportation Integrated Search

1992-12-01

Last year, the City of Portland decided to place geotextile fabrics under asphalt concrete overlays for pavement reinforcement and crack retardation. The City expected the following benefits from using the fabrics: retardation of reflective cracks, r...

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

NASA Astrophysics Data System (ADS)

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.

The challenges of transitioning from linear to high-order overlay control in advanced lithography

NASA Astrophysics Data System (ADS)

Adel, M.; Izikson, P.; Tien, D.; Huang, C. K.; Robinson, J. C.; Eichelberger, B.

2008-03-01

In the lithography section of the ITRS 2006 update, at the top of the list of difficult challenges appears the text "overlay of multiple exposures including mask image placement". This is a reflection of the fact that today overlay is becoming a major yield risk factor in semiconductor manufacturing. Historically, lithographers have achieved sufficient alignment accuracy and hence layer to layer overlay control by relying on models which define overlay as a linear function of the field and wafer coordinates. These linear terms were easily translated to correctibles in the available exposure tool degrees of freedom on the wafer and reticle stages. However, as the 45 nm half pitch node reaches production, exposure tool vendors have begun to make available, and lithographers have begun to utilize so called high order wafer and field control, in which either look up table or high order polynomial models are modified on a product by product basis. In this paper, the major challenges of this transition will be described. It will include characterization of the sources of variation which need to be controlled by these new models and the overlay and alignment sampling optimization problem which needs to be addressed, while maintaining the ever tightening demands on productivity and cost of ownership.

Maxillary overlay removable partial dentures for the restoration of worn teeth.

PubMed

Fonseca, Júlio; Nicolau, Pedro; Daher, Tony

2011-04-01

Prolonged tooth maintenance by a more aged population considerably increases the probability of dentists having to treat patients with high levels of tooth wear. Pathological tooth wear, caused primarily by parafunction, seems to be a growing problem that affects a large number of adult patients. The clinical report presents a case of a partially edentulous patient with an elevated degree of wear in the upper jaw caused by attrition and erosion, rehabilitated with a maxillary overlay removable partial denture (ORPD) consisting of a chrome-cobalt (Cr-Co) framework with anterior acrylic resin veneers, posterior cast overlays, and acrylic resin denture bases. Removable partial prosthesis is a treatment alternative when teeth are found to be severely worn or when the patient needs a simple and economical option. Because economics is a conditional factor of the treatment, the clinician should present different treatment alternatives to the patient, in which the overlay prosthesis can be considered.

Effect of a Dielectric Overlay on a Linearly Tapered Slot Antenna Excited by a Coplanar Waveguide

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Lee, Richard Q.; Perl, Thomas D.; Silvestro, John

1993-01-01

The effect of a dielectric overlay on a linearly tapered slot antenna (LTSA) is studied. The LTSA under study has very wide bandwidth and excellent radiation patterns. A dielectric overlay improves the patterns and directivity of the antenna by increasing the electrical length and effective aperture of the antenna. A dielectric overlay can also be used to reduce the physical length of the antenna without compromising the pattern quality.

Tunable in-line fiber optic comb filter using a side-polished single-mode fiber coupler with LiNbO 3 overlay and intermediate coupling layer

NASA Astrophysics Data System (ADS)

Sohn, Kyung-Rak; Song, Jae-Won

2002-03-01

Using a side-polished single-mode fiber covered with a polished LiNbO 3 overlay and an intermediate coupling layer, tunable fiber-optic comb filters are demonstrated. The device behaviors based on the modal properties of the fiber and the planar LiNbO 3 waveguide are analyzed by two dimensional beam propagation methods (2-D BPM) and discussed the role of an intermediate coupling layer in terms of coupling efficiency. We also show that the thermo-optic effects of this layer can be utilized to tune the comb filter. When the polished x-cut LiNbO 3 with 200 μm thickness is used as a multimode overlay waveguide, the comb output spectra with free spectral range of 4 nm are measured in 1550 nm wavelength range. The tuning rate as a function of the refractive index of an intermediate coupling layer, Δλ/ Δnb, is about -0.129 nm/-0.001. The experimental results are in good agreement with the calculated results.

Crack sealing before overlaying an asphalt concrete surface.

DOT National Transportation Integrated Search

1997-01-01

In an attempt to reduce reflective cracking on overlay projects a study was conducted that : consisted of sealing all transverse cracks greater than inch with hot crack sealers before the : project was resurfaced. The experiment will evaluate the ...

Polymer concrete bridge deck overlays : Deschutes River Bridge (Biggs) and Maupin Bridge (Maupin) : final report.

DOT National Transportation Integrated Search

1995-07-01

This report documents the construction and performance of two thin polymer concrete (with polyester/styrene resins) bridge deck overlays. The overlays were constructed in Biggs and Maupin, Oregon in June 1993. : Several problems were encountered duri...

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

PubMed

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.

Overview of latex modified concrete overlays : final report.

DOT National Transportation Integrated Search

1984-01-01

Twelve bridges with latex modified concrete (LMC) overlays ranging in age from new to 13 years were studied and their general condition found to be good. The half-cell and chloride data were inconclusive because background data were not available for...

Crosslayer Survivability in Overlay-IP-WDM Networks

ERIC Educational Resources Information Center

Pacharintanakul, Peera

2010-01-01

As the Internet moves towards a three-layer architecture consisting of overlay networks on top of the IP network layer on top of WDM-based physical networks, incorporating the interaction between and among network layers is crucial for efficient and effective implementation of survivability. This dissertation has four major foci as follows:…

On the Impact of Snow Salinity on CryoSat-2 First-Year Sea Ice Thickness Retrievals

NASA Astrophysics Data System (ADS)

Nandan, V.; Yackel, J.; Geldsetzer, T.; Mahmud, M.

2017-12-01

European Space Agency's Ku-band altimeter CryoSat-2 (CS-2) has demonstrated its potential to provide extensive basin-scale spatial and temporal measurements of Arctic sea ice freeboard. It is assumed that CS-2 altimetric returns originate from the snow/sea ice interface (assumed to be the main scattering horizon). However, in newly formed thin ice ( 0.6 m) through to thick first-year sea ice (FYI) ( 2 m), upward wicking of brine into the snow cover from the underlying sea ice surface produces saline snow layers, especially in the bottom 6-8 cm of a snow cover. This in turn modifies the brine volume at/or near the snow/sea ice interface, altering the dielectric and scattering properties of the snow cover, leading to strong Ku-band microwave attenuation within the upper snow volume. Such significant reductions in Ku-band penetration may substantially affect CS-2 FYI freeboard retrievals. Therefore, the goal of this study is to evaluate a theoretical approach to estimate snow salinity induced uncertainty on CS-2 Arctic FYI freeboard measurements. Using the freeboard-to-thickness hydrostatic equilibrium equation, we quantify the error differences between the CS-2 FYI thickness, (assuming complete penetration of CS-2 radar signals to the snow/FYI interface), and the FYI thickness based on the modeled Ku-band main scattering horizon for different snow cover cases. We utilized naturally occurring saline and non-saline snow cover cases ranging between 6 cm to 32 cm from the Canadian Arctic, observed during late-winter from 1993 to 2017, on newly-formed ice ( 0.6 m), medium ( 1.5 m) and thick FYI ( 2 m). Our results suggest that irrespective of the thickness of the snow cover overlaying FYI, the thickness of brine-wetted snow layers and actual FYI freeboard strongly influence the amount with which CS-2 FYI freeboard estimates and thus thickness calculations are overestimated. This effect is accentuated for increasingly thicker saline snow covers overlaying newly-formed ice

Advanced overlay: sampling and modeling for optimized run-to-run control

NASA Astrophysics Data System (ADS)

Subramany, Lokesh; Chung, WoongJae; Samudrala, Pavan; Gao, Haiyong; Aung, Nyan; Gomez, Juan Manuel; Gutjahr, Karsten; Park, DongSuk; Snow, Patrick; Garcia-Medina, Miguel; Yap, Lipkong; Demirer, Onur Nihat; Pierson, Bill; Robinson, John C.

2016-03-01

In recent years overlay (OVL) control schemes have become more complicated in order to meet the ever shrinking margins of advanced technology nodes. As a result, this brings up new challenges to be addressed for effective run-to- run OVL control. This work addresses two of these challenges by new advanced analysis techniques: (1) sampling optimization for run-to-run control and (2) bias-variance tradeoff in modeling. The first challenge in a high order OVL control strategy is to optimize the number of measurements and the locations on the wafer, so that the "sample plan" of measurements provides high quality information about the OVL signature on the wafer with acceptable metrology throughput. We solve this tradeoff between accuracy and throughput by using a smart sampling scheme which utilizes various design-based and data-based metrics to increase model accuracy and reduce model uncertainty while avoiding wafer to wafer and within wafer measurement noise caused by metrology, scanner or process. This sort of sampling scheme, combined with an advanced field by field extrapolated modeling algorithm helps to maximize model stability and minimize on product overlay (OPO). Second, the use of higher order overlay models means more degrees of freedom, which enables increased capability to correct for complicated overlay signatures, but also increases sensitivity to process or metrology induced noise. This is also known as the bias-variance trade-off. A high order model that minimizes the bias between the modeled and raw overlay signature on a single wafer will also have a higher variation from wafer to wafer or lot to lot, that is unless an advanced modeling approach is used. In this paper, we characterize the bias-variance trade off to find the optimal scheme. The sampling and modeling solutions proposed in this study are validated by advanced process control (APC) simulations to estimate run-to-run performance, lot-to-lot and wafer-to- wafer model term monitoring to

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

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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.

Flexible pavement overlay design procedures. Volume 1: Evaluation and modification of the design methods

NASA Astrophysics Data System (ADS)

Majidzadeh, K.; Ilves, G. J.

1981-08-01

A ready reference to design procedures for asphaltic concrete overlay of flexible pavements based on elastic layer theory is provided. The design procedures and the analytical techniques presented were formulated to predict the structural fatigue response of asphaltic concrete overlays for various design conditions, including geometrical and material properties, loading conditions and environmental variables.

Utilizing Lab Tests to Predict Asphalt Concrete Overlay Performance

DOT National Transportation Integrated Search

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...

Measuring, Achieving, And Promoting Smoothness Of Virginia's Asphalt Overlays

DOT National Transportation Integrated Search

1999-04-01

This study was initiated with the goal of identifying the predominant factors affecting the achievable smoothness of asphalt overlays. In addition, the researcher chronicles the evolution of Virginia's innovative special provision for smoothness, whi...

Prosthodontic management of worn dentition in pediatric patient with complete overlay dentures: a case report

PubMed Central

Rastogi, Jyoti; Jain, Chandni; Singh, Harkanwal Preet

2012-01-01

Overlay complete dentures are simple, reversible and economical treatment modality for patients with congenital or acquired disorders that severely affect the tooth development. It satisfies both the esthetic and functional demands where the extraction of teeth is not generally indicated. In pediatric patients, the overlay dentures establish a relatively stable occlusion that improves patient's tolerance to the future treatment procedures for worn dentition. This clinical report highlights the imperative need of appropriate treatment strategy and application of maxillary and mandibular overlay dentures in a pediatric patient who suffered from congenitally mutilated and worn dentition. PMID:23236577

Flutter Analysis of the Shuttle Tile Overlay Repair Concept

NASA Technical Reports Server (NTRS)

Bey, Kim S.; Scott, Robert C.; Bartels, Robert E.; Waters, William A.; Chen, Roger

2007-01-01

The Space Shuttle tile overlay repair concept, developed at the NASA Johnson Space Center, is designed for on-orbit installation over an area of damaged tile to permit safe re-entry. The thin flexible plate is placed over the damaged area and secured to tile at discreet points around its perimeter. A series of flutter analyses were performed to determine if the onset of flutter met the required safety margins. Normal vibration modes of the panel, obtained from a simplified structural analysis of the installed concept, were combined with a series of aerodynamic analyses of increasing levels of fidelity in terms of modeling the flow physics to determine the onset of flutter. Results from these analyses indicate that it is unlikely that the overlay installed at body point 1800 will flutter during re-entry.

Development of guidelines and specifications for use of WMA technology in delivering HMA products inclusive of non-conventional mixtures such as SMA's, and mixtures with high RAP and RAS content.

DOT National Transportation Integrated Search

2014-08-01

This report documents the work completed in WHRP Project 0092-12-02, Development of Guidelines and Specifications : for Use of WMA Technology in Delivering HMA Products Inclusive of Non-Conventional Mixtures Such as SMAs, and : Mixtures with High ...

Performance specification for high performance concrete overlays on bridges.

DOT National Transportation Integrated Search

2004-01-01

Hydraulic cement concrete overlays are usually placed on bridges to reduce the infiltration of water and chloride ions and to improve skid resistance, ride quality, and surface appearance. Constructed in accordance with prescription specifications, s...

Measuring, achieving and promoting smoothness of Virginia's asphalt overlays.

DOT National Transportation Integrated Search

1999-01-01

This study was initiated with the goal of identifying the predominant factors affecting the achievable smoothness of asphalt overlays. In addition, it chronicles the evolution of Virginia's innovative special provision for smoothness, which was devel...

Performance Evaluation of Cognitive Interference Channels Using a Spectrum Overlay Strategy

NASA Technical Reports Server (NTRS)

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.

Ultrasound-ultrasound image overlay fusion improves real-time control of radiofrequency ablation margin in the treatment of hepatocellular carcinoma.

PubMed

Minami, Yasunori; Minami, Tomohiro; Hagiwara, Satoru; Ida, Hiroshi; Ueshima, Kazuomi; Nishida, Naoshi; Murakami, Takamichi; Kudo, Masatoshi

2018-05-01

To assess the clinical feasibility of US-US image overlay fusion with evaluation of the ablative margin in radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). Fifty-three patients with 68 HCCs measuring 0.9-4.0 cm who underwent RFA guided by US-US overlay image fusion were included in this retrospective study. By an overlay of pre-/postoperative US, the tumor image could be projected onto the ablative hyperechoic zone. Therefore, the ablative margin three-dimensionally could be shown during the RFA procedure. US-US image overlay was compared to dynamic CT a few days after RFA for assessment of early treatment response. Accuracy of graded response was calculated, and the performance of US-US image overlay fusion was compared with that of CT using a Kappa agreement test. Technically effective ablation was achieved in a single session, and 59 HCCs (86.8 %) succeeded in obtaining a 5-mm margin on CT. The response with US-US image overlay correctly predicted early CT evaluation with an accuracy of 92.6 % (63/68) (k = 0.67; 95 % CI: 0.39-0.95). US-US image overlay fusion can be proposed as a feasible guidance in RFA with a safety margin and predicts early response of treatment assessment with high accuracy. • US-US image overlay fusion visualizes the ablative margin during RFA procedure. • Visualizing the margin during the procedure can prompt immediate complementary treatment. • US image fusion correlates with the results of early evaluation CT.

Investigation of Tensile Creep of a Normal Strength Overlay Concrete.

PubMed

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.

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

PubMed

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 (p<0.0001.). The optimal cutoff of color overlay pattern was between 2 and 3. Emax with optimal cutoff at 45.1 kPa showed the highest Az value, sensitivity, specificity and accuracy among other quantitative SWE parameters (p<0.0001). Echogenic halo on grayscale US showed significant correlation with color overlay pattern and pathology (p<0.0001). In evaluation of palpable breast 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.

Capability for Fine Tuning of the Refractive Index Sensing Properties of Long-Period Gratings by Atomic Layer Deposited Al2O3 Overlays

PubMed Central

Śmietana, Mateusz; Myśliwiec, Marcin; Mikulic, Predrag; Witkowski, Bartłomiej S.; Bock, Wojtek J.

2013-01-01

This work presents an application of thin aluminum oxide (Al2O3) films obtained using atomic layer deposition (ALD) for fine tuning the spectral response and refractive-index (RI) sensitivity of long-period gratings (LPGs) induced in optical fibers. The technique allows for an efficient and well controlled deposition at monolayer level (resolution ∼ 0.12 nm) of excellent quality nano-films as required for optical sensors. The effect of Al2O3 deposition on the spectral properties of the LPGs is demonstrated experimentally and numerically. We correlated both the increase in Al2O3 thickness and changes in optical properties of the film with the shift of the LPG resonance wavelength and proved that similar films are deposited on fibers and oxidized silicon reference samples in the same process run. Since the thin overlay effectively changes the distribution of the cladding modes and thus also tunes the device's RI sensitivity, the tuning can be simply realized by varying number of cycles, which is proportional to thickness of the high-refractive-index (n > 1.6 in infrared spectral range) Al2O3 film. The advantage of this approach is the precision in determining the film properties resulting in RI sensitivity of the LPGs. To the best of our knowledge, this is the first time that an ultra-precise method for overlay deposition has been applied on LPGs for RI tuning purposes and the results have been compared with numerical simulations based on LP mode approximation.

Athermal Silicon-on-insulator ring resonators by overlaying a polymer cladding on narrowed waveguides.

PubMed

Teng, Jie; Dumon, Pieter; Bogaerts, Wim; Zhang, Hongbo; Jian, Xigao; Han, Xiuyou; Zhao, Mingshan; Morthier, Geert; Baets, Roel

2009-08-17

Athermal silicon ring resonators are experimentally demonstrated by overlaying a polymer cladding on narrowed silicon wires. The ideal width to achieve athermal condition for the TE mode of 220 nm-height SOI waveguides is found to be around 350 nm. After overlaying a polymer layer, the wavelength temperature dependence of the silicon ring resonator is reduced to less than 5 pm/degrees C, almost eleven times less than that of normal silicon waveguides. The optical loss of a 350-nm bent waveguide (with a radius of 15 microm) is extracted from the ring transmission spectrum. The scattering loss is reduced to an acceptable level of about 50 dB/cm after overlaying a polymer cladding. (c) 2009 Optical Society of America

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

NASA Astrophysics Data System (ADS)

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.

Styrene-butadiene latex modifiers for bridge deck overlay concrete.

DOT National Transportation Integrated Search

1978-04-01

Styrene-butadiene (S/B) latex modified concrete overlays are being used to protect : new bridge decks from rapid deicer-borne chloride intrusion and also in bridge : deck rehabilitation efforts. The purposes of this research were to evaluate several ...

Investigation of silica fume concrete bridge deck overlay failures.

DOT National Transportation Integrated Search

2016-02-23

Many of these microsilica-modified concrete or silica fume concrete (SFC) bridge deck overlays across the State of Wyoming are suffering from premature distress that includes random cracking, loss of bond and delaminations. To determine the most like...

Advances in process overlay on 300-mm wafers

NASA Astrophysics Data System (ADS)

Staecker, Jens; Arendt, Stefanie; Schumacher, Karl; Mos, Evert C.; van Haren, Richard J. F.; van der Schaar, Maurits; Edart, Remi; Demmerle, Wolfgang; Tolsma, Hoite

2002-07-01

Overlay budgets are getting tighter within 300 mm volume production and as a consequence the process effects on alignment and off-line metrology becomes more important. In a short loop experiment, with cleared reference marks in each image field, the isolated effect of processing was measured with a sub-nanometer accuracy. The examined processes are Shallow Trench Isolation (STI), Tungsten-Chemical Mechanical Processing (W-CMP) and resist spinning. The alignment measurements were done on an ASML TWINSCANT scanner and the off-line metrology measurements on a KLA Tencor. Mark type and mark position dependency of the process effects are analyzed. The mean plus 3 (sigma) of the maximum overlay after correcting batch average wafer parameters is used as an overlay performance indicator (OPI). 3 (sigma) residuals to the wafer-model are used as an indicator of the noise that is added by the process. The results are in agreement with existing knowledge of process effects on 200 mm wafers. The W-CMP process introduces an additional wafer rotation and scaling that is similar for alignment marks and metrology targets. The effects depend on the mark type; in general they get less severe for higher spatial frequencies. For a 7th order alignment mark, the OPI measured about 12 nm and the added noise about 12 nm. For the examined metrology targets the OPI is about 20 nm with an added noise of about 90 nm. Two different types of alignment marks were tested in the STI process, i.e., zero layer marks and marks that were exposed together with the STI product. The overlay contribution due to processing on both types of alignment marks is very low (smaller than 5 nm OPI) and independent on mark type. Some flyers are observed fot the zero layer marks. The flyers can be explained by the residues of oxide and nitride that is left behind in the spaces of the alignment marks. Resist spinning is examined on single layer resist and resist with an organic Bottom Anti-Reflective Coating (BARC

Performance of an unbonded concrete overlay on I-74

DOT National Transportation Integrated Search

2002-04-01

In Illinois, the typical rehabilitation for a concrete pavement is full-depth patching of the distressed concrete, and overlaying the pavement with 3.25 inches of bituminous concrete. In cases where there are poor joints or extensive durability crack...

Thickness and composition of ultrathin SiO2 layers on Si

NASA Astrophysics Data System (ADS)

van der Marel, C.; Verheijen, M. A.; Tamminga, Y.; Pijnenburg, R. H. W.; Tombros, N.; Cubaynes, F.

2004-07-01

Ultrathin SiO2 layers are of importance for the semiconductor industry. One of the techniques that can be used to determine the chemical composition and thickness of this type of layers is x-ray photoelectron spectroscopy (XPS). As shown by Seah and Spencer [Surf. Interface Anal. 33, 640 (2002)], it is not trivial to characterize this type of layer by means of XPS in a reliable way. We have investigated a series of ultrathin layers of SiO2 on Si (in the range from 0.3 to 3 nm) using XPS. The samples were also analyzed by means of transmission electron microscopy (TEM), Rutherford backscattering (RBS), and ellipsometry. The thickness of the SiO2 layers (d) was determined from the XPS results using three different approaches: the ``standard'' equation (Seah and Spencer) for d, an overlayer-substrate model calculation, and the QUASES-Tougaard [Surf. Interface Anal. 26, 249 (1998), QUASES-Tougaard: Software package for Quantitative Analysis of Surfaces by Electron Spectroscopy, version 4.4 (2000); http://www.quases.com] method. Good agreement was obtained between the results of XPS analyses using the ``standard'' equation, the overlayer-substrate model calculation, and RBS results. The QUASES-Tougaard results were approximately 62% above the other XPS results. The optical values for the thickness were always slightly higher than the thickness according to XPS or RBS. Using the model calculation, these (relatively small) deviations from the optical results could be explained as being a consequence of surface contaminations with hydrocarbons. For a thickness above 2.5 nm, the TEM results were in good agreement with the results obtained from the other techniques (apart from QUASES-Tougaard). Below 2.5 nm, significant deviations were found between RBS, XPS, and optical data on the one hand and TEM results on the other hand; the deviations became larger as the thickness of the SiO2 decreased. This effect may be related to interface states of oxygen, which have been

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

PubMed

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

Type A polymer concrete overlay field trials : interim report.

DOT National Transportation Integrated Search

1982-12-01

On July 31 and August 1, 1982, the Oregon State Highway Division successfully placed a methyl methacrylate polymer concrete overlay on a portion of one span of a major interchange ramp in Portland, Oregon. Two proprietary polymer concretes were used ...

Forensic Study of Early Failures with Unbonded Concrete Overlays

DOT National Transportation Integrated Search

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...

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Ridge preservation comparing socket allograft alone to socket allograft plus facial overlay xenograft: a clinical and histologic study in humans.

PubMed

Poulias, Evmenios; Greenwell, Henry; Hill, Margaret; Morton, Dean; Vidal, Ricardo; Shumway, Brian; Peterson, Thomas L

2013-11-01

Previous studies of ridge preservation showed a loss of ≈18% or 1.5 mm of crestal ridge width in spite of treatment. The primary aim of this randomized, controlled, masked clinical trial is to compare a socket graft to the same treatment plus a buccal overlay graft, both with a polylactide membrane, to determine if loss of ridge width can be prevented by use of an overlay graft. Twelve patients who served as positive controls received an intrasocket mineralized cancellous allograft (socket group), and 12 patients received the same socket graft procedure plus buccal overlay cancellous xenograft (overlay group). Horizontal ridge dimensions were measured with a digital caliper, and vertical ridge changes were measured from a stent. Before implant placement, at 4 months, a trephine core was obtained for histologic analysis. The mean horizontal ridge width at the crest for the socket group decreased from 8.7 ± 1.0 to 7.1 ± 1.5 mm for a mean loss of 1.6 ± 0.8 mm (P <0.05), whereas the same measurement for the overlay group decreased from 8.4 ± 1.4 to 8.1 ± 1.4 mm for a mean loss of 0.3 ± 0.9 mm (P >0.05). The overlay group was significantly different from the socket group (P <0.05). Histologic analysis revealed that the socket group had 35% ± 16% vital bone, and the overlay group had 40% ± 16% (P >0.05). The overlay treatment significantly prevented loss of ridge width and preserved or augmented the buccal contour. The socket and overlay groups healed with a high percentage of vital bone.

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

NASA Astrophysics Data System (ADS)

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.

Recovery of Sublethally Injured Bacteria Using Selective Agar Overlays.

ERIC Educational Resources Information Center

McKillip, John L.

2001-01-01

This experiment subjects bacteria in a food sample and an environmental sample to conditions of sublethal stress in order to assess the effectiveness of the agar overlay method to recover sublethally injured cells compared to direct plating onto the appropriate selective medium. (SAH)

Diffusion Barriers to Increase the Oxidative Life of Overlay Coatings

NASA Technical Reports Server (NTRS)

Nesbitt, James A.; Lei, Jih-Fen

1999-01-01

Currently, most blades and vanes in the hottest section of aero gas turbine engines require some type of coating for oxidation protection. Newly developed single crystal superalloys have the mechanical potential to operate at increasingly higher component temperatures. However, at these elevated temperatures, coating/substrate interdiffusion can shorten the protective life of the coating. Diffusion barriers between overlay coatings and substrates are being examined to extend the protective life of the coating. A previously- developed finite-difference diffusion model has been modified to predict the oxidative life enhancement due to use of a diffusion barrier. The original diffusion model, designated COSIM, simulates Al diffusion in the coating to the growing oxide scale as well as Al diffusion into the substrate. The COSIM model incorporates an oxide growth and spalling model to provide the rate of Al consumption during cyclic oxidation. Coating failure is predicted when the Al concentration at the coating surface drops to a defined critical level. The modified COSIM model predicts the oxidative life of an overlay coating when a diffusion barrier is present eliminating diffusion of Al from the coating into the substrate. Both the original and the modified diffusion models have been used to predict the effectiveness of a diffusion barrier in extending the protective life of a NiCrAl overlay coating undergoing cyclic oxidation at 1100 C.

Modeling the dynamical interaction between epidemics on overlay networks

NASA Astrophysics Data System (ADS)

Marceau, Vincent; Noël, Pierre-André; Hébert-Dufresne, Laurent; Allard, Antoine; Dubé, Louis J.

2011-08-01

Epidemics seldom occur as isolated phenomena. Typically, two or more viral agents spread within the same host population and may interact dynamically with each other. We present a general model where two viral agents interact via an immunity mechanism as they propagate simultaneously on two networks connecting the same set of nodes. By exploiting a correspondence between the propagation dynamics and a dynamical process performing progressive network generation, we develop an analytical approach that accurately captures the dynamical interaction between epidemics on overlay networks. The formalism allows for overlay networks with arbitrary joint degree distribution and overlap. To illustrate the versatility of our approach, we consider a hypothetical delayed intervention scenario in which an immunizing agent is disseminated in a host population to hinder the propagation of an undesirable agent (e.g., the spread of preventive information in the context of an emerging infectious disease).

Latex modified asphalt and experimental joint treatments on asphaltic concrete overlays : experimental project No. 3 : asphalt additives.

DOT National Transportation Integrated Search

1988-06-01

This report documents the construction and initial evaluation of several experimental features which were incorporated as part of an overlay of an existing PCC pavement in order to determine the feasibility of extending overlay service life. The expe...

Questioning the Benefits That Coloured Overlays Can Have for Reading in Students with and without Dyslexia

ERIC Educational Resources Information Center

Henderson, Lisa M.; Tsogka, Natassa; Snowling, Margaret J.

2013-01-01

Visual stress (the experience of visual distortions and discomfort during prolonged reading) is frequently identified and alleviated with coloured overlays or lenses. Previous studies have associated visual stress with dyslexia and as a consequence, coloured overlays are widely distributed to children and adults with reading difficulty. However,…

Evaluation of the construction and performance of polymer concrete overlays on five bridges : interim report no. 1.

DOT National Transportation Integrated Search

1983-01-01

The installation of thin polymer concrete overlays on five bridges on I-85 near Williamsburg, Virginia, has demonstrated that an overlay of low permeability and high skid resistance can be successfully installed by a contractor with a minimum of disr...

Passivation of hematite nanorod photoanodes with a phosphorus overlayer for enhanced photoelectrochemical water oxidation

NASA Astrophysics Data System (ADS)

Xiong, Dehua; Li, Wei; Wang, Xiaoguang; Liu, Lifeng

2016-09-01

Hematite (i.e., α-Fe2O3) nanorod photoanodes passivated with a phosphorus overlayer have been fabricated by decomposing sodium hypophosphite (NaH2PO2) at a low temperature over the hematite nanorod surface. Extensive scanning electron microscopy, transmission electron microscopy, x-ray diffractometry and UV-vis spectroscopy characterizations confirm that conformal deposition of an amorphous phosphorus overlayer does not change the crystal structure, morphology, and optical absorption properties of hematite photoanodes. X-ray photoelectron spectroscopy reveals that phosphorus in the deposited overlayer exists in an oxidized state. Comprehensive steady-state polarization, transient photocurrent response, and impedance spectroscopy measurements as well as Mott-Schottky analysis manifest that the phosphorus overlayer is able to effectively passivate surface states and suppress electron-hole recombination, substantially enhancing the photocurrent for water oxidation. Combining the phosphorization treatment with two-step thermal activation, a photocurrent density of 1.1 mA cm-2 is achieved at 1.23 V versus reversible hydrogen electrode under illumination of 100 mW cm-2, ca 55 times higher than that of the non-activated pristine hematite photoanode measured under the same conditions. The simple and fast phosphorization strategy we present here can be readily applied to passivate surfaces of other semiconductor photoelectrodes to improve their photoelectrochemical performance.

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

DOT National Transportation Integrated Search

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...

Evaluation of a thin-bonded Portland cement concrete pavement overlay.

DOT National Transportation Integrated Search

1996-01-01

This report discusses the performance of the Virginia Department of Transportation's first modern rehabilitation project involving a thin-bonded portland cement concrete overlay of an existing jointed concrete pavement. The performance of the rigid o...

Single-layer graphdiyne-covered Pt(111) surface: improved catalysis confined under two-dimensional overlayer

NASA Astrophysics Data System (ADS)

Chen, Xi; Lin, Zheng-Zhe

2018-05-01

In recent years, two-dimensional confined catalysis, i.e., the enhanced catalytic reactions in confined space between metal surface and two-dimensional overlayer, makes a hit and opens up a new way to enhance the performance of catalysts. In this work, graphdiyne overlayer was proposed as a more excellent material than graphene or hexagonal boron nitride for two-dimensional confined catalysis on Pt(111) surface. Density functional theory calculations revealed the superiority of graphdiyne overlayer originates from the steric hindrance effect which increases the catalytic ability and lowers the reaction barriers. Moreover, with the big triangle holes as natural gas tunnels, graphdiyne possesses higher efficiency for the transit of gaseous reactants and products than graphene or hexagonal boron nitride. The results in this work would benefit future development of two-dimensional confined catalysis. [Figure not available: see fulltext.

Evaluation of thin asphalt overlay practice preserving Nebraska's asphalt pavements.

DOT National Transportation Integrated Search

2015-06-01

This study examined the current thin asphalt overlay practices implemented in Nebraska. To that end, the mechanical : properties and performance characteristics of the two mixtures (i.e., SLX and SPH) were compared by carrying out : laboratory tests ...

Comparison of survival time and comfort between 2 clear overlay retainers with different thicknesses: A pilot randomized controlled trial.

PubMed

Zhu, Yafen; Lin, Jianchang; Long, Hu; Ye, Niansong; Huang, Renhuan; Yang, Xin; Jian, Fan; Lai, Wenli

2017-03-01

The objective of this 2-arm parallel trial was to compare the survival times, failure rates, and comfort of 2 clear overlay retainers with different thicknesses (0.75 and 1.00 mm). Eighty eligible participants who had undergone orthodontic treatment at West China Stomatology Hospital of Sichuan University were recruited and randomly assigned to either the 0.75-mm group or the 1.00-mm group. Eligibility criteria included patients with central incisors, canines, and first molars and no systemic or oral disease. The main outcomes were survival time and total failure rate; the secondary outcomes were rates of different types of failure (fracture, loss, nonfitting, and abrasion); tertiary outcomes included patients' comfort levels assessed with a visual analog scale and a health survey. Randomization was accomplished by tossing a coin, with the allocations concealed in sequentially numbered, opaque, sealed envelopes, and blinding implemented among practitioners, patients, and analysts. Patients were evaluated at 1, 3, 6, and 12 months of follow-up. A total of 80 patients were initially recruited and randomized (42 in the 0.75-mm group, 38 in the 1.00-mm group); 72 patients completed the study and were analyzed (37 in the 0.75-mm group, 35 in the 1.00-mm group); there were 8 dropouts. Baseline characteristics were similar between the groups. At the end of the 1-year follow-up, survival time did not differ significantly between the groups (46.5 days; 95% confidence interval [CI], -10.3 -103.2; P = 0.111). The hazard ratio was 0.77 (95% CI, 0.48-1.24; P = 0.281). With regard to total failure rate, no statistical difference (P = 0.118) existed between the 0.75-mm group (43.2%) and the 1.00-mm group (25.7%) (risk difference, 17.5%; 95% CI, -4.0%-39.1%). Among the different failure types, we found that fracture rates were significantly higher in the 0.75-mm group than in the 1.00-mm group (P = 0.028), whereas other failure types were similar between the groups

Study of behaviors of aluminum overlayers deposited on uranium via AES, EELS, and XPS

NASA Astrophysics Data System (ADS)

Liu, Kezhao; Luo, Lizhu; Zhou, Wei; Yang, Jiangrong; Xiao, Hong; Hong, Zhanglian; Yang, Hui

2013-04-01

Aluminum overlayers on uranium were prepared by sputtering at room temperature in an ultra-high vacuum chamber. The growth mode of aluminum overlayers and behaviors of the Al/U interface reaction were studied in situ by auger electron spectroscopy, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy. The results suggested that the interdiffusion took place at the Al/U interface during the initial stage of deposition. The U4f spectra of the Al/U interface showed strong correlation satellites at binding energies of 380.4 and 392.7 eV and plasma loss features at 404.2 eV, respectively. The interactions between aluminum and uranium yielded the intermetallic compound of UAlx, inducing the shift to a low binding energy for Al2p peaks. The results indicated that aluminum overlayers were formed on the uranium by sputtering in an island growth mode.

Use of Hydrogen Chemisorption and Ethylene Hydrogenation as Predictors for Aqueous Phase Reforming of Lactose over Ni@Pt and Co@Pt Bimetallic Overlayer Catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lai, Qinghua; Skoglund, Michael D.; Zhang, Chen

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, furthermore » 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.« less

Evaluation of Geosynthetics in Asphalt Overlays of Jointed Concrete Pavements

DOT National Transportation Integrated Search

2000-06-01

This report presents the findings and recommendations based on the Evaluation of Geosynthetics in Asphalt Overlays of Jointed Concrete Pavements. This project evaluated Linq Tac-711N and Strata Grid-200's ability to ease distress and reflective crack...

Growth and structural evolution of Sn on Ag(001): Epitaxial monolayer to thick alloy film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, Suvankar; Menon, Krishnakumar S. R., E-mail: krishna.menon@saha.ac.in

The growth and structure of Sn on Ag(001), from submonolayer to thick film coverages at room temperature, are studied using low energy electron diffraction, x-ray photoemission spectroscopy and angle-resolved photoemission spectroscopy (ARPES) techniques. The authors observe different growth modes for submonolayer Sn coverages and for higher Sn coverages. Systematic surface structural evolution, consistent with the substitution of surface Ag atoms by Sn atoms, is observed for submonolayer Sn coverages while an ordered Ag-Sn bulk alloy film is formed for higher Sn coverages with an Ag overlayer. For monolayer coverage of Sn, a pseudomorphic growth of a Sn layer without alloyingmore » is determined. ARPES results also confirm the presence of an ordered Ag overlayer on the bulk Ag-Sn alloy film, suggesting the formation of an Ag/Ag{sub 3}Sn/Ag(001) sandwich structure at the surface for higher Sn coverages. The present results illustrate the complex interplay of atomic mobilities, surface free-energies, and alloy formation energies in determining the growth and structural properties of the system.« less

Evaluation of the installation and initial condition of hydraulic cement concrete overlays placed on three pavements in Virginia.

DOT National Transportation Integrated Search

1999-04-01

Hydraulic cement concrete pavement overlays were placed in the summer of 1995 at the following locations in Virginia: : 1-295 near Richmond : 1-85 near Petersburg : Rt. 29 near Charlottesville. : Overlays were placed on 1-295 SBL (near mi...

Polymer concrete overlay test program : Lebanon Ditch Bridge : final report.

DOT National Transportation Integrated Search

1983-01-01

This report presents information on the installation of a thin polymer concrete overlay and the evaluation of its durability after a 15-month in-service period. The project was performed by the Oregon State Highway Division under the sponsorship of t...

Continued implementation of high performance thin overlays in Texas districts.

DOT National Transportation Integrated Search

2017-06-22

As part of Research Project 0-5598, outputs include guidelines and specifications on how a district can design and construct long-life overlays using the concept of balanced mix design; and training materials describing the best ways to select, desig...

Reducing overlay sampling for APC-based correction per exposure by replacing measured data with computational prediction

NASA Astrophysics Data System (ADS)

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.

Accounting for nanometer-thick adventitious carbon contamination in X-ray absorption spectra of carbon-based materials.

PubMed

Mangolini, Filippo; McClimon, J Brandon; Rose, Franck; Carpick, Robert W

2014-12-16

Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is a powerful technique for characterizing the composition and bonding state of nanoscale materials and the top few nanometers of bulk and thin film specimens. When coupled with imaging methods like photoemission electron microscopy, it enables chemical imaging of materials with nanometer-scale lateral spatial resolution. However, analysis of NEXAFS spectra is often performed under the assumption of structural and compositional homogeneity within the nanometer-scale depth probed by this technique. This assumption can introduce large errors when analyzing the vast majority of solid surfaces due to the presence of complex surface and near-surface structures such as oxides and contamination layers. An analytical methodology is presented for removing the contribution of these nanoscale overlayers from NEXAFS spectra of two-layered systems to provide a corrected photoabsorption spectrum of the substrate. This method relies on the subtraction of the NEXAFS spectrum of the overlayer adsorbed on a reference surface from the spectrum of the two-layer system under investigation, where the thickness of the overlayer is independently determined by X-ray photoelectron spectroscopy (XPS). This approach is applied to NEXAFS data acquired for one of the most challenging cases: air-exposed hard carbon-based materials with adventitious carbon contamination from ambient exposure. The contribution of the adventitious carbon was removed from the as-acquired spectra of ultrananocrystalline diamond (UNCD) and hydrogenated amorphous carbon (a-C:H) to determine the intrinsic photoabsorption NEXAFS spectra of these materials. The method alters the calculated fraction of sp(2)-hybridized carbon from 5 to 20% and reveals that the adventitious contamination can be described as a layer containing carbon and oxygen ([O]/[C] = 0.11 ± 0.02) with a thickness of 0.6 ± 0.2 nm and a fraction of sp(2)-bonded carbon of 0.19 ± 0.03. This

Efficient hybrid metrology for focus, CD, and overlay

NASA Astrophysics Data System (ADS)

Tel, W. T.; Segers, B.; Anunciado, R.; Zhang, Y.; Wong, P.; Hasan, T.; Prentice, C.

2017-03-01

In the advent of multiple patterning techniques in semiconductor industry, metrology has progressively become a burden. With multiple patterning techniques such as Litho-Etch-Litho-Etch and Sidewall Assisted Double Patterning, the number of processing step have increased significantly and therefore, so as the amount of metrology steps needed for both control and yield monitoring. The amount of metrology needed is increasing in each and every node as more layers needed multiple patterning steps, and more patterning steps per layer. In addition to this, there is that need for guided defect inspection, which in itself requires substantially denser focus, overlay, and CD metrology as before. Metrology efficiency will therefore be cruicial to the next semiconductor nodes. ASML's emulated wafer concept offers a highly efficient method for hybrid metrology for focus, CD, and overlay. In this concept metrology is combined with scanner's sensor data in order to predict the on-product performance. The principle underlying the method is to isolate and estimate individual root-causes which are then combined to compute the on-product performance. The goal is to use all the information available to avoid ever increasing amounts of metrology.

Disbond detection with piezoelectric wafer active sensors in RC structures strengthened with FRP composite overlays

NASA Astrophysics Data System (ADS)

Giurgiutiu, Victor; Harries, Kent; Petrou, Michael; Bost, Joel; Quattlebaum, Josh B.

2003-12-01

The capability of embedded piezoelectric wafer active sensors (PWAS) to perform in-situ nondestructive evaluation (NDE) for structural health monitoring (SHM) of reinforced concrete (RC) structures strengthened with fiber reinforced polymer (FRP) composite overlays is explored. First, the disbond detection method were developed on coupon specimens consisting of concrete blocks covered with an FRP composite layer. It was found that the presence of a disbond crack drastically changes the electromechanical (E/M) impedance spectrum measured at the PWAS terminals. The spectral changes depend on the distance between the PWAS and the crack tip. Second, large scale experiments were conducted on a RC beam strengthened with carbon fiber reinforced polymer (CFRP) composite overlay. The beam was subject to an accelerated fatigue load regime in a three-point bending configuration up to a total of 807,415 cycles. During these fatigue tests, the CFRP overlay experienced disbonding beginning at about 500,000 cycles. The PWAS were able to detect the disbonding before it could be reliably seen by visual inspection. Good correlation between the PWAS readings and the position and extent of disbond damage was observed. These preliminary results demonstrate the potential of PWAS technology for SHM of RC structures strengthened with FRP composite overlays.

An MR-based Model for Cardio-Respiratory Motion Compensation of Overlays in X-Ray Fluoroscopy

PubMed Central

Fischer, Peter; Faranesh, Anthony; Pohl, Thomas; Maier, Andreas; Rogers, Toby; Ratnayaka, Kanishka; Lederman, Robert; Hornegger, Joachim

2017-01-01

In X-ray fluoroscopy, static overlays are used to visualize soft tissue. We propose a system for cardiac and respiratory motion compensation of these overlays. It consists of a 3-D motion model created from real-time MR imaging. Multiple sagittal slices are acquired and retrospectively stacked to consistent 3-D volumes. Slice stacking considers cardiac information derived from the ECG and respiratory information extracted from the images. Additionally, temporal smoothness of the stacking is enhanced. Motion is estimated from the MR volumes using deformable 3-D/3-D registration. The motion model itself is a linear direct correspondence model using the same surrogate signals as slice stacking. In X-ray fluoroscopy, only the surrogate signals need to be extracted to apply the motion model and animate the overlay in real time. For evaluation, points are manually annotated in oblique MR slices and in contrast-enhanced X-ray images. The 2-D Euclidean distance of these points is reduced from 3.85 mm to 2.75 mm in MR and from 3.0 mm to 1.8 mm in X-ray compared to the static baseline. Furthermore, the motion-compensated overlays are shown qualitatively as images and videos. PMID:28692969

12. DETAIL INDICATING TRANSITION FROM ORIGINAL SURFACE TO GUNITE OVERLAY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. DETAIL INDICATING TRANSITION FROM ORIGINAL SURFACE TO GUNITE OVERLAY ON UPSTREAM EMBANKMENT OF DAM (FROM REPAIRS COMPLETED IN 1977) - Upper Doughty Dam, 200 feet west of Garden State Parkway, 1.7 miles west of Absecon, Egg Harbor City, Atlantic County, NJ

Promoting Learning of Instructional Design via Overlay Design Tools

ERIC Educational Resources Information Center

Carle, Andrew Jacob

2012-01-01

I begin by introducing Virtual Design Apprenticeship (VDA), a learning model--built on a solid foundation of education principles and theories--that promotes learning of design skills via overlay design tools. In VDA, when an individual needs to learn a new design skill or paradigm she is provided accessible, concrete examples that have been…

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

NASA Astrophysics Data System (ADS)

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

A comparative study between xerographic, computer-assisted overlay generation and animated-superimposition methods in bite mark analyses.

PubMed

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.

An assessment of SBS modified asphalt concrete pavements performance features performing numerical analysis

NASA Astrophysics Data System (ADS)

Karakas, Ahmet Sertac; Bozkurt, Tarik Serhat; Sayin, Baris; Ortes, Faruk

2017-07-01

In passenger and freight traffic on the roads, which has the largest share of the hot mix asphalt (HMA) prepared asphalt concrete pavement is one of the most preferred type of flexible superstructure. During the service life of the road, they must provide the performance which is expected to show. HMA must be high performance mix design, comfortable, safe and resistance to degradation. In addition, it becomes a critical need to use various additives materials for roads to be able to serve long-term against environmental conditions such as traffic and climate due to the fact that the way of raw materials is limited. Styrene Butadiene Styrene (SBS) polymers are widely used among additives. In this study, the numerical analysis of SBS modified HMA designed asphalt concrete coatings prepared with different thicknesses with SBS modified HMA is performed. After that, stress and deformation values of the three pavement models are compared and evaluated.

Assessment of the Potential for Color Overlays to Enhance the Reading Skills of Enlisted Navy Recruits

DTIC Science & Technology

2006-07-30

as an intervention . Readers with MIS symptoms read significantly faster with their chosen overlay than without it. These findings justify further...recent years, the techniques for routine diagnosis and effective intervention methods for MIS have been improved and developed. Although Irlen is...The British Royal Navy, for example, screens for MIS on a case-by-case basis and provides overlays and filters as intervention . Furthermore

High order field-to-field corrections for imaging and overlay to achieve sub 20-nm lithography requirements

NASA Astrophysics Data System (ADS)

Mulkens, Jan; Kubis, Michael; Hinnen, Paul; de Graaf, Roelof; van der Laan, Hans; Padiy, Alexander; Menchtchikov, Boris

2013-04-01

Immersion lithography is being extended to the 20-nm and 14-nm node and the lithography performance requirements need to be tightened further to enable this shrink. In this paper we present an integral method to enable high-order fieldto- field corrections for both imaging and overlay, and we show that this method improves the performance with 20% - 50%. The lithography architecture we build for these higher order corrections connects the dynamic scanner actuators with the angle resolved scatterometer via a separate application server. Improvements of CD uniformity are based on enabling the use of freeform intra-field dose actuator and field-to-field control of focus. The feedback control loop uses CD and focus targets placed on the production mask. For the overlay metrology we use small in-die diffraction based overlay targets. Improvements of overlay are based on using the high order intra-field correction actuators on a field-tofield basis. We use this to reduce the machine matching error, extending the heating control and extending the correction capability for process induced errors.

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

NASA Astrophysics Data System (ADS)

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.

Kenny-Caffey Syndrome: oral findings and 4-year follow-up of overlay denture therapy.

PubMed

Demir, Tahsin; Kecik, Defne; Cehreli, Zafer C

2007-01-01

Kenny-Caffey Syndrome (KCS) is an extremely rare osteosclerotic bone dysplasia associated with hypocalcemia and ocular abnormalities. Although the condition is well reported in the medical literature, dental manifestations have not been discussed in great detail. The purpose of this report is to present specific oral features and prosthetic management in a KCS patient. Overlay dentures were utilized in the management of low vertical dimension of occlusion, congenital absence of several permanent teeth, and problems associated with function and esthetics. Results of the 4-year follow-up overlay denture therapy are presented.

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

NASA Astrophysics Data System (ADS)

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.

Texas flexible pavements and overlays : data analysis plans and reporting format.

DOT National Transportation Integrated Search

2012-01-01

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 valida...

Surface crystallographic structures of cellulose nanofiber films and overlayers of pentacene

NASA Astrophysics Data System (ADS)

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.

Investigation of the weldability of iron-aluminum-chromium overlay coatings for corrosion protection in oxidizing/sulfidizing environments

NASA Astrophysics Data System (ADS)

Regina, Jonathan R.

The current study investigated the effect of chromium additions on the hydrogen cracking susceptibility of Fe-Al weld overlay claddings containing chromium additions. It was found that the weldability of FeAlCr claddings was a function of both the aluminum and chromium concentrations of the weld coatings. Weld overlay compositions that were not susceptible to hydrogen cracking were identified and the underlying mechanism behind the hydrogen cracking phenomenon was investigated further. It was concluded that the cracking behavior of the FeAlCr welds depended strongly on the microstructure of the weld fusion zone. Although it was found that the cracking susceptibility was influenced by the presence of Fe-Al intermetallic phases (namely Fe3 Al and FeAl), the cracking behavior of FeAlCr weld overlay claddings also depended on the size and distribution of carbide and oxide particles present within the weld structure. These particles acted as hydrogen trapping sites, which are areas where free hydrogen segregates and can no longer contribute to the hydrogen embrittlement of the metal. It was determined that in practical applications of these FeAlCr weld overlay coatings, carbon should be present within these welds to reduce the amount of hydrogen available for hydrogen cracking. Based on the weldability results of the FeAlCr weld claddings, coating compositions that were able to be deposited crack-free were used for long-term corrosion testing in a simulated low NOx environment. These alloys were compared to a Ni-based superalloy (622), which is commonly utilized as boiler tube coatings in power plant furnaces for corrosion protection. It was found that the FeAlCr alloys demonstrated superior corrosion resistance when compared to the Ni-based superalloy. Due to the excellent long-term corrosion behavior of FeAlCr weld overlays that were immune to hydrogen cracking, it was concluded that select FeAlCr weld overlay compositions would make excellent corrosion resistant

Semantic Overlays in Educational Content Networks--The hylOs Approach

ERIC Educational Resources Information Center

Engelhardt, Michael; Hildebrand, Arne; Lange, Dagmar; Schmidt, Thomas C.

2006-01-01

Purpose: The paper aims to introduce an educational content management system, Hypermedia Learning Objects System (hylOs), which is fully compliant to the IEEE LOM eLearning object metadata standard. Enabled through an advanced authoring toolset, hylOs allows the definition of instructional overlays of a given eLearning object mesh.…

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

NASA Astrophysics Data System (ADS)

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.

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

DOT National Transportation Integrated Search

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...

Latex and microsilica modified concrete bridge deck overlays in Oregon : interim report.

DOT National Transportation Integrated Search

1994-08-01

This interim report presented information collected from 24 bridge deck overlays constructed in Oregon between 1989 and 1993. Decks were placed on a variety of existing structures using hydroblasting, milling and diamond grinding surface preparation....

Plastocyanin Controls the Stabilization of the Thylakoid Cu-transporting P-type ATPase PAA2/HMA8 in Response to Low Copper in Arabidopsis*

PubMed Central

Tapken, Wiebke; Ravet, Karl; Pilon, Marinus

2012-01-01

PAA2/HMA8 (P-type ATPase of Arabidopsis/Heavy-metal-associated 8) is a thylakoid located copper (Cu)-transporter in Arabidopsis thaliana. In tandem with PAA1/HMA6, which is located in the inner chloroplast envelope, it supplies Cu to plastocyanin (PC), an essential cuproenzyme of the photosynthetic machinery. We investigated whether the chloroplast Cu transporters are affected by Cu addition to the growth media. Immunoblots showed that PAA2 protein abundance decreased significantly and specifically when Cu in the media was increased, while PAA1 remained unaffected. The function of SPL7, the transcriptional regulator of Cu homeostasis, was not required for this regulation of PAA2 protein abundance and Cu addition did not affect PAA2 transcript levels, as determined by qRT-PCR. We used the translational inhibitor cycloheximide to analyze turnover and observed that the stability of the PAA2 protein was decreased in plants grown with elevated Cu. Interestingly, PAA2 protein abundance was significantly increased in paa1 mutants, in which the Cu content in the chloroplast is half of that of the wild-type, due to impaired Cu import into the organelle. In contrast in a pc2 insertion mutant, which has strongly reduced plastocyanin expression, the PAA2 protein levels were low regardless of Cu addition to the growth media. Together, these data indicate that plastid Cu levels control PAA2 stability and that plastocyanin, which is the target of PAA2 mediated Cu delivery in thylakoids, is a major determinant of this regulatory mechanism. PMID:22493454

The effect of coloured overlays and lenses on reading: a systematic review of the literature.

PubMed

Griffiths, Philip G; Taylor, Robert H; Henderson, Lisa M; Barrett, Brendan T

2016-09-01

There are many anecdotal claims and research reports that coloured lenses and overlays improve reading performance. Here we present the results of a systematic review of this literature and examine the quality of the evidence. We systematically reviewed the literature concerning the effect of coloured lenses or overlays on reading performance by searching the PsychInfo, Medline and Embase databases. This revealed 51 published items (containing 54 data sets). Given that different systems are in use for issuing coloured overlays or lenses, we reviewed the evidence under four separate system headings (Intuitive, Irlen, Harris/Chromagen and Other), classifying each published item using the Cochrane Risk of Bias tool. Although the different colour systems have been subjected to different amounts of scientific scrutiny, the results do not differ according to the system type, or whether the sample under investigation was classified as having visual stress (or a similarly defined condition), reading difficulty, or both. The majority of studies are subject to 'high' or 'uncertain' risk of bias in one or more key aspects of study design or outcome, with studies at lower risk from bias providing less support for the benefit of coloured lenses/overlays on reading ability. While many studies report improvements with coloured lenses, the effect size is generally small and/or similar to the improvement found with a placebo condition. We discuss the strengths and shortcomings of the published literature and, whilst acknowledging the difficulties associated with conducting trials of this type, offer some suggestions about how future trials might be conducted. Consistent with previous reviews and advice from several professional bodies, we conclude that the use of coloured lenses or overlays to ameliorate reading difficulties cannot be endorsed and that any benefits reported by individuals in clinical settings are likely to be the result of placebo, practice or Hawthorne effects. �

Orthogonal Rings, Fiducial Markers, and Overlay Accuracy When Image Fusion is Used for EVAR Guidance.

PubMed

Koutouzi, G; Sandström, C; Roos, H; Henrikson, O; Leonhardt, H; Falkenberg, M

2016-11-01

Evaluation of orthogonal rings, fiducial markers, and overlay accuracy when image fusion is used for endovascular aortic repair (EVAR). This was a prospective single centre study. In 19 patients undergoing standard EVAR, 3D image fusion was used for intra-operative guidance. Renal arteries and targeted stent graft positions were marked with rings orthogonal to the respective centre lines from pre-operative computed tomography (CT). Radiopaque reference objects attached to the back of the patient were used as fiducial markers to detect patient movement intra-operatively. Automatic 3D-3D registration of the pre-operative CT with an intra-operative cone beam computed tomography (CBCT) as well as 3D-3D registration after manual alignment of nearby vertebrae were evaluated. Registration was defined as being sufficient for EVAR guidance if the deviation of the origin of the lower renal artery was less than 3 mm. For final overlay registration, the renal arteries were manually aligned using aortic calcification and vessel outlines. The accuracy of the overlay before stent graft deployment was evaluated using digital subtraction angiography (DSA) as direct comparison. Fiducial markers helped in detecting misalignment caused by patient movement during the procedure. Use of automatic intensity based registration alone was insufficient for EVAR guidance. Manual registration based on vertebrae L1-L2 was sufficient in 7/19 patients (37%). Using the final adjusted registration as overlay, the median alignment error of the lower renal artery marking at pre-deployment DSA was 2 mm (0-5) sideways and 2 mm (0-9) longitudinally, mostly in a caudal direction. 3D image fusion can facilitate intra-operative guidance during EVAR. Orthogonal rings and fiducial markers are useful for visualization and overlay correction. However, the accuracy of the overlaid 3D image is not always ideal and further technical development is needed. Copyright © 2016 European Society for Vascular Surgery

Active membrane masks for improved overlay performance in proximity lithography

NASA Astrophysics Data System (ADS)

Huston, Dryver R.; Plumpton, James; Esser, Brian; Sullivan, Gerald A.

2004-07-01

Membrane masks are thin (2 micron x 35 mm x 35 mm) structures that carry the master exposure patterns in proximity (X-ray) lithography. With the continuous drive to the printing of ever-finer features in microelectronics, the reduction of mask-wafer overlay positioning errors by passive rigid body positioning and passive stress control in the mask becomes impractical due to nano and sub-micron scale elastic deformations in the membrane mask. This paper describes the design, mechanics and performance of a system for actively stretching a membrane mask in-plane to control overlay distortion. The method uses thermoelectric heating/cooling elements placed on the mask perimeter. The thermoelectric elements cause controlled thermoelastic deformations in the supporting wafer, which in turn corrects distortions in the membrane mask. Silicon carbide masks are the focus of this study, but the method is believed to be applicable to other mask materials, such as diamond. Experimental and numerical results will be presented, as well as a discussion of the design issues and related design decisions.

Dynamics analysis of epidemic and information spreading in overlay networks.

PubMed

Liu, Guirong; Liu, Zhimei; Jin, Zhen

2018-05-07

We establish an SIS-UAU model to present the dynamics of epidemic and information spreading in overlay networks. The overlay network is represented by two layers: one where the dynamics of the epidemic evolves and another where the information spreads. We theoretically derive the explicit formulas for the basic reproduction number of awareness R 0 a by analyzing the self-consistent equation and the basic reproduction number of disease R 0 d by using the next generation matrix. The formula of R 0 d shows that the effect of awareness can reduce the basic reproduction number of disease. In particular, when awareness does not affect epidemic spreading, R 0 d is shown to match the existing theoretical results. Furthermore, we demonstrate that the disease-free equilibrium is globally asymptotically stable if R 0 d <1; and the endemic equilibrium is globally asymptotically stable if R 0 d >1. Finally, numerical simulations show that information plays a vital role in preventing and controlling disease and effectively reduces the final disease scale. Copyright © 2018 Elsevier Ltd. All rights reserved.

Overlay improvement by exposure map based mask registration optimization

NASA Astrophysics Data System (ADS)

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

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

NASA Astrophysics Data System (ADS)

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.

Electronic structure of dense Pb overlayers on Si(111) investigated using angle-resolved photoemission

NASA Astrophysics Data System (ADS)

Choi, W. H.; Koh, H.; Rotenberg, E.; Yeom, H. W.

2007-02-01

Dense Pb overlayers on Si(111) are important as the wetting layer for anomalous Pb island growth as well as for their own complex “devil’s-staircase” phases. The electronic structures of dense Pb overlayers on Si(111) were investigated in detail by angle-resolved photoemission. Among the series of ordered phases found recently above one monolayer, the low-coverage 7×3 and the high-coverage 14×3 phases are studied; they are well ordered and form reproducibly in large areas. The band dispersions and Fermi surfaces of the two-dimensional (2D) electronic states of these overlayers are mapped out. A number of metallic surface-state bands are identified for both phases with complex Fermi contours. The basic features of the observed Fermi contours can be explained by overlapping 2D free-electron-like Fermi circles. This analysis reveals that the 2D electrons near the Fermi level of the 7×3 and 14×3 phases are mainly governed by strong 1×1 and 3×3 potentials, respectively. The origins of the 2D electronic states and their apparent Fermi surface shapes are discussed based on recent structure models.

Latex and microsilica modified concrete bridge deck overlays in Oregon : final report.

DOT National Transportation Integrated Search

1997-05-01

The final report presents information collected by ODOT personnel from bridge deck overlays constructed in Oregon between 1989 and 1995. Decks were placed on a variety of existing bridge types prepared using hydrodemolition, milling, and diamond grin...

Image overlay solution based on threshold detection for a compact near infrared fluorescence goggle system

NASA Astrophysics Data System (ADS)

Gao, Shengkui; Mondal, Suman B.; Zhu, Nan; Liang, RongGuang; Achilefu, Samuel; Gruev, Viktor

2015-01-01

Near infrared (NIR) fluorescence imaging has shown great potential for various clinical procedures, including intraoperative image guidance. However, existing NIR fluorescence imaging systems either have a large footprint or are handheld, which limits their usage in intraoperative applications. We present a compact NIR fluorescence imaging system (NFIS) with an image overlay solution based on threshold detection, which can be easily integrated with a goggle display system for intraoperative guidance. The proposed NFIS achieves compactness, light weight, hands-free operation, high-precision superimposition, and a real-time frame rate. In addition, the miniature and ultra-lightweight light-emitting diode tracking pod is easy to incorporate with NIR fluorescence imaging. Based on experimental evaluation, the proposed NFIS solution has a lower detection limit of 25 nM of indocyanine green at 27 fps and realizes a highly precise image overlay of NIR and visible images of mice in vivo. The overlay error is limited within a 2-mm scale at a 65-cm working distance, which is highly reliable for clinical study and surgical use.

Photoemission intensity oscillations from quantum-well states in the Ag/V(100) overlayer system

NASA Astrophysics Data System (ADS)

Milun, M.; Pervan, P.; Gumhalter, B.; Woodruff, D. P.

1999-02-01

Extensive measurements have been made of the photoemission intensities recorded along the surface normal from quantum-well (QW) states of pseudomorphic Ag layers on V(100) in thicknesses from 1-7 ML as a function of photon energy in the range 15-45 eV. In all cases the QW states lead to intense peaks in the photoemission spectra which show strong oscillations in intensity with photon energy, the energy period of the oscillations becoming shorter as the films become thicker. These effects are explained in terms of interference of surface and interfaces photoemission from the sharp changes in potential at the well boundaries, and a semiquantitative description is achieved via calculations based on a simple asymmetric square-well description in the Adawi formulation of surface photoemission. An alternative picture in which intensity peaks are predicted to correspond to the conditions for direct transitions from bulk states of the overlayer material at the same initial-state energy is shown to be in direct contradiction with some of our observations. The reason for this failure, and the relationship of alternative views of the physical processes, are discussed.

CFDP for Interplanetary Overlay Network

NASA Technical Reports Server (NTRS)

Burleigh, Scott C.

2011-01-01

The CCSDS (Consultative Committee for Space Data Systems) File Delivery Protocol for Interplanetary Overlay Network (CFDP-ION) is an implementation of CFDP that uses IO' s DTN (delay tolerant networking) implementation as its UT (unit-data transfer) layer. Because the DTN protocols effect automatic, reliable transmission via multiple relays, CFDP-ION need only satisfy the requirements for Class 1 ("unacknowledged") CFDP. This keeps the implementation small, but without loss of capability. This innovation minimizes processing resources by using zero-copy objects for file data transmission. It runs without modification in VxWorks, Linux, Solaris, and OS/X. As such, this innovation can be used without modification in both flight and ground systems. Integration with DTN enables the CFDP implementation itself to be very simple; therefore, very small. Use of ION infrastructure minimizes consumption of storage and processing resources while maximizing safety.

A complete methodology towards accuracy and lot-to-lot robustness in on-product overlay metrology using flexible wavelength selection

NASA Astrophysics Data System (ADS)

Bhattacharyya, Kaustuve; den Boef, Arie; Noot, Marc; Adam, Omer; Grzela, Grzegorz; Fuchs, Andreas; Jak, Martin; Liao, Sax; Chang, Ken; Couraudon, Vincent; Su, Eason; Tzeng, Wilson; Wang, Cathy; Fouquet, Christophe; Huang, Guo-Tsai; Chen, Kai-Hsiung; Wang, Y. C.; Cheng, Kevin; Ke, Chih-Ming; Terng, L. G.

2017-03-01

The optical coupling between gratings in diffraction-based overlay triggers a swing-curve1,6 like response of the target's signal contrast and overlay sensitivity through measurement wavelengths and polarizations. This means there are distinct measurement recipes (wavelength and polarization combinations) for a given target where signal contrast and overlay sensitivity are located at the optimal parts of the swing-curve that can provide accurate and robust measurements. Some of these optimal recipes can be the ideal choices of settings for production. The user has to stay away from the non-optimal recipe choices (that are located on the undesirable parts of the swing-curve) to avoid possibilities to make overlay measurement error that can be sometimes (depending on the amount of asymmetry and stack) in the order of several "nm". To accurately identify these optimum operating areas of the swing-curve during an experimental setup, one needs to have full-flexibility in wavelength and polarization choices. In this technical publication, a diffraction-based overlay (DBO) measurement tool with many choices of wavelengths and polarizations is utilized on advanced production stacks to study swing-curves. Results show that depending on the stack and the presence of asymmetry, the swing behavior can significantly vary and a solid procedure is needed to identify a recipe during setup that is robust against variations in stack and grating asymmetry. An approach is discussed on how to use this knowledge of swing-curve to identify recipe that is not only accurate at setup, but also robust over the wafer, and wafer-to-wafer. KPIs are reported in run-time to ensure the quality / accuracy of the reading (basically acting as an error bar to overlay measurement).

Evaluation of iron aluminide weld overlays for erosion - corrosion resistant boiler tube coatings in low NO{sub x} boilers

DOE Office of Scientific and Technical Information (OSTI.GOV)

DuPont, J.N.; Banovic, S.W.; Marder, A.R.

1996-08-01

Low NOx burners are being installed in many fossil fired power plants in order to comply with new Clean Air Regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion is often enhanced and premature tube failures can occur. Failures due to oxidation and solid particle erosion are also a concern. A program was initiated in early 1996 to evaluate the use of iron aluminide weld overlays for erosion/corrosion protection of boiler tubes in Low NOx boilers. Composite iron/aluminum wires will be used with the Gas Metal Arc Welding (GMAW) process to prepare overlays on boiler tubesmore » steels with aluminum contents from 8 to 16wt%. The weldability of the composite wires will be evaluated as a function of chemical composition and welding parameters. The effect of overlay composition on corrosion (oxidation and sulfidation) and solid particle erosion will also be evaluated. The laboratory studies will be complemented by field exposures of both iron aluminide weld overlays and co-extruded tubing under actual boiler conditions.« less

Full-scale bonded concrete overlay on IH-30 in Ft. Worth, Texas

DOT National Transportation Integrated Search

2000-10-01

This report presents the research and recommendations regarding the rehabilitation of an urban section of IH-30 in west Fort Worth, Texas. Bonded concrete overlays have proven to be a viable solution for rehabilitation of heavily traveled pavement se...

Evaluation of thin epoxy system overlays for concrete bridge decks : final report.

DOT National Transportation Integrated Search

1991-12-01

Four overlay systems were applied to concrete bridge decks in north Louisiana in May 1995 to evaluate their performance as friction surface and also as concrete sealers. Dural Flexolith, Poly-Carb Flexogrid, and Con/Chem Con/Crete were placed on thre...

Assessment of Potential Location of High Arsenic Contamination Using Fuzzy Overlay and Spatial Anisotropy Approach in Iron Mine Surrounding Area

PubMed Central

Wirojanagud, Wanpen; Srisatit, Thares

2014-01-01

Fuzzy overlay approach on three raster maps including land slope, soil type, and distance to stream can be used to identify the most potential locations of high arsenic contamination in soils. Verification of high arsenic contamination was made by collection samples and analysis of arsenic content and interpolation surface by spatial anisotropic method. A total of 51 soil samples were collected at the potential contaminated location clarified by fuzzy overlay approach. At each location, soil samples were taken at the depth of 0.00-1.00 m from the surface ground level. Interpolation surface of the analysed arsenic content using spatial anisotropic would verify the potential arsenic contamination location obtained from fuzzy overlay outputs. Both outputs of the spatial surface anisotropic and the fuzzy overlay mapping were significantly spatially conformed. Three contaminated areas with arsenic concentrations of 7.19 ± 2.86, 6.60 ± 3.04, and 4.90 ± 2.67 mg/kg exceeded the arsenic content of 3.9 mg/kg, the maximum concentration level (MCL) for agricultural soils as designated by Office of National Environment Board of Thailand. It is concluded that fuzzy overlay mapping could be employed for identification of potential contamination area with the verification by surface anisotropic approach including intensive sampling and analysis of the substances of interest. PMID:25110751

Evaluation of the Installation and Initial Condition of Rosphalt Overlays on Bridge Decks.

DOT National Transportation Integrated Search

2013-06-01

"Protection systems are placed on bridge decks to retard the intrusion of chlorides and moisture that can eventually cause : corrosion deterioration. The Virginia Department of Transportation typically uses hydraulic cement concrete (HCC) overlays of...

Evaluation of Some Finishing Properties of Oil Palm Particleboard for Furniture Application

NASA Astrophysics Data System (ADS)

Ratnasingam, J.; Nyugen, V.; Ioras, F.

The finishing properties of particleboard made from the Empty-Fruit Bunch (EFB) of oil palm (Elaeis guineensis Jacq.) were evaluated for its suitability for furniture applications, using different coating and overlay materials. The results found that the thick plastic-formica overlay provided the best surface finish, in terms of surface smoothness, adhesion strength and impact resistance. Although the polyurethane lacquer provided an acceptable finish, its quality and performance is not comparable to that of the thick plastic overlay. Despite the fact that the use of such overlay material may render the material not aesthetically appealing and limit it to concealed applications or where the thick overlay material is tolerated, its cost competitiveness and environmental friendliness may be able to position the oil palm particleboard as a substitute for the conventional wood-based particleboard in the furniture manufacturing industry.

Evaluation of bonded concrete overlays over asphalt under accelerated loading : research project capsule.

DOT National Transportation Integrated Search

2014-05-01

The overall objective of this research study is to evaluate the structural performance and loadcarrying : capacity of bonded concrete overlay pavement structures through accelerated pavement : testing and document the experience of mix design and con...

Complete Overlay Denture for Pedodontic Patient with Severe Dentinogenesis Imperfecta

PubMed Central

Joseph, Elizabeth; Rupesh, Suresh; Mathew, Josey

2017-01-01

Dentinogenesis imperfecta (DI) is a hereditary condition that may affect both primary and permanent dentition and is characterized by abnormal dentin formation. The teeth may be discolored with chipping of enamel and, in untreated cases, the entire dentition may wear off to the gingiva. This may lead to the formation of abscesses, tooth mobility, and early loss of teeth. In the Indian population, DI is found to have an incidence of 0.09%. Treatment of DI should aim to remove infection, if any, from the oral cavity; restore form, function, and esthetics; and protect posterior teeth from wear for maintaining the occlusal vertical dimension. Treatment strategies should be selected based on the presenting complaint of the patient, patient’s age, and severity of the problem. This case report presents the management of severe DI with tooth worn off until gingival level in a very young patient using complete overlay denture, which has not been reported earlier. How to cite this article: Syriac G, Joseph E, Rupesh S, Mathew J. Complete Overlay Denture for Pedodontic Patient with Severe Dentinogenesis Imperfecta. Int J Clin Pediatr Dent 2017;10(4):394-398. PMID:29403236

Complete Overlay Denture for Pedodontic Patient with Severe Dentinogenesis Imperfecta.

PubMed

Syriac, Gibi; Joseph, Elizabeth; Rupesh, Suresh; Mathew, Josey

2017-01-01

Dentinogenesis imperfecta (DI) is a hereditary condition that may affect both primary and permanent dentition and is characterized by abnormal dentin formation. The teeth may be discolored with chipping of enamel and, in untreated cases, the entire dentition may wear off to the gingiva. This may lead to the formation of abscesses, tooth mobility, and early loss of teeth. In the Indian population, DI is found to have an incidence of 0.09%. Treatment of DI should aim to remove infection, if any, from the oral cavity; restore form, function, and esthetics; and protect posterior teeth from wear for maintaining the occlusal vertical dimension. Treatment strategies should be selected based on the presenting complaint of the patient, patient's age, and severity of the problem. This case report presents the management of severe DI with tooth worn off until gingival level in a very young patient using complete overlay denture, which has not been reported earlier. How to cite this article: Syriac G, Joseph E, Rupesh S, Mathew J. Complete Overlay Denture for Pedodontic Patient with Severe Dentinogenesis Imperfecta. Int J Clin Pediatr Dent 2017;10(4):394-398.

Efficacy of coloured overlays and lenses for treating reading difficulty: an overview of systematic reviews.

PubMed

Suttle, Catherine M; Lawrenson, John G; Conway, Miriam L

2018-04-06

Coloured overlays or lenses are widely available for use by children and adults with difficulties or discomfort while reading. In recent years, systematic reviews have been conducted in an attempt to establish the strength of the evidence base for this intervention. The aim of this overview is to systematically review these reviews. The methodology was published prospectively as a protocol (Prospero CRD42017059172). Online databases Medline, Cinahl, Embase and the Cochrane Library were searched for systematic reviews on the efficacy of coloured overlays or lenses for the alleviation of reading difficulty or discomfort. Included studies were appraised using the AMSTAR 2 checklist. Characteristics of included studies such as aspects of methods, results and conclusions were recorded. Both processes were conducted independently by two reviewers and any discrepancies were resolved by discussion. Thirty-one studies were found via databases and other sources. After excluding duplicates and those not fitting the inclusion criteria, four reviews were included in the analysis. While all reviews were systematic, their methodology, results and conclusions differed. Three of the four concluded that there is insufficient good quality evidence to support the use of coloured overlays or lenses for reading difficulty, while one concluded that, despite research limitations, the evidence does support their use. On balance, systematic reviews to date indicate that there is not yet a reliable evidence base on which to recommend coloured overlays or lenses for the alleviation of reading difficulty or discomfort. High quality, low bias research is needed to investigate their effectiveness in different forms of reading difficulty and discomfort for adults and children. © 2018 Optometry Australia.

Overlay accuracy on a flexible web with a roll printing process based on a roll-to-roll system.

PubMed

Chang, Jaehyuk; Lee, Sunggun; Lee, Ki Beom; Lee, Seungjun; Cho, Young Tae; Seo, Jungwoo; Lee, Sukwon; Jo, Gugrae; Lee, Ki-yong; Kong, Hyang-Shik; Kwon, Sin

2015-05-01

For high-quality flexible devices from printing processes based on Roll-to-Roll (R2R) systems, overlay alignment during the patterning of each functional layer poses a major challenge. The reason is because flexible substrates have a relatively low stiffness compared with rigid substrates, and they are easily deformed during web handling in the R2R system. To achieve a high overlay accuracy for a flexible substrate, it is important not only to develop web handling modules (such as web guiding, tension control, winding, and unwinding) and a precise printing tool but also to control the synchronization of each unit in the total system. A R2R web handling system and reverse offset printing process were developed in this work, and an overlay between the 1st and 2nd layers of ±5μm on a 500 mm-wide film was achieved at a σ level of 2.4 and 2.8 (x and y directions, respectively) in a continuous R2R printing process. This paper presents the components and mechanisms used in reverse offset printing based on a R2R system and the printing results including positioning accuracy and overlay alignment accuracy.

Evaluation of concrete slab fracturing techniques in mitigating reflective cracking through asphalt overlays.

DOT National Transportation Integrated Search

2002-09-01

This report presents the results of an evaluation of concrete slab fracturing techniques as a means of arresting or retarding reflective cracking through asphalt overlays placed on severely distressed portland cement concrete pavement. The study invo...

Between-subject variability in asymmetry analysis of macular thickness.

PubMed

Alluwimi, Muhammed S; Swanson, William H; Malinovsky, Victor E

2014-05-01

To investigate the use of asymmetry analysis to reduce between-subject variability of macular thickness measurements using spectral domain optical coherence tomography. Sixty-three volunteers (33 young subjects [aged 21 to 35 years] and 30 older subjects [aged 45 to 85 years]) free of eye disease were recruited. Macular images were gathered with the Spectralis optical coherence tomography. An overlay 24- by 24-degree grid was divided into five zones per hemifield, and asymmetry analysis was computed as the difference between superior and inferior zone thicknesses. We hypothesized that the lowest variation and the highest density of ganglion cells will be found approximately 3 to 6 degrees from the foveola, corresponding to zones 1 and 2. For each zone and age group, between-subject SDs were compared for retinal thickness versus asymmetry analysis using an F test. To account for repeated comparisons, p < 0.0125 was required for statistical significance. Axial length and corneal curvature were measured with an IOLMaster. For OD, asymmetry analysis reduced between-subject variability in zones 1 and 2 in both groups (F > 3.2, p < 0.001). Standard deviation for zone 1 dropped from 12.0 to 3.0 μm in the young group and from 11.7 to 2.6 μm in the older group. Standard deviation for zone 2 dropped from 13.6 to 5.3 μm in the young group and from 11.1 to 5.8 μm in the older group. Combining all subjects, neither retinal thickness nor asymmetry analysis showed a strong correlation with axial length or corneal curvature (R² < 0.01). Analysis for OS yielded the same pattern of results, as did asymmetry analyses between eyes (F > 3.8, p < 0.0001). Asymmetry analysis reduced between-subject variability in zones 1 and 2. Combining the five zones together produced a higher between-subject variation of the retinal thickness asymmetry analysis; thus, we encourage clinicians to be cautious when interpreting the asymmetry analysis printouts.

Construction of a thin-bonded Portland cement concrete overlay using accelerated paving techniques.

DOT National Transportation Integrated Search

1992-01-01

The report describes the Virginia Department of Transportations' first modern experience with the construction of thin-bonded Portland cement concrete overlays of existing concrete pavements and with the fast track mode of rigid paving. The study was...

Issues pertaining to the permeability characteristics of coarsegraded Superpave mixes

DOT National Transportation Integrated Search

2002-07-01

In order to evaluate the relationships between in-place air voids, lift thickness, and permeability, 23 on-going HMA construction projects were visited and field permeability tests conducted. Field permeability tests were conducted at 15 randomly det...

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

NASA Astrophysics Data System (ADS)

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.

Interlayer Stress Absorbing Composite (ISAC) for Mitigating Reflection Cracking in Asphalt Concrete Overlays

DOT National Transportation Integrated Search

1996-06-01

To approach the reflection cracking problem in AC overlays systematically the properties of the materials intended to be used in an ISAC system were first identified. Various thermal/structural models and laboratory equipment were used for this purpo...

The Effects of a Dynamic Spectrum Access Overlay in LTE-Advanced Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Juan D. Deaton; Ryan E. Irwin; Luiz A. DaSilva

As early as 2014, mobile network operators’ spectral capacity will be overwhelmed by the demand brought on by new devices and applications. To augment capacity and meet this demand, operators may choose to deploy a Dynamic Spectrum Access (DSA) overlay. The signaling and functionality required by such an overlay have not yet been fully considered in the architecture of the planned Long Term Evolution Advanced (LTE+) networks. This paper presents a Spectrum Accountability framework to be integrated into LTE+ architectures, defining specific element functionality, protocol interfaces, and signaling flow diagrams required to enforce the rights and responsibilities of primary andmore » secondary users. We also quantify, through integer programs, the benefits of using DSA channels to augment capacity under a scenario in which LTE+ network can opportunistically use TV and GSM spectrum. The framework proposed here may serve as a guide in the development of future LTE+ network standards that account for DSA.« less

Fracture patterns of glass-ionomer cement overlays versus stainless steel bands during endodontic treatment: an ex-vivo study.

PubMed

Pakdeethai, S; Abuzar, M; Parashos, P

2013-12-01

To compare fracture patterns of posterior teeth temporized with: mesio-occlusal-distal (MOD) glass-ionomer cement (GIC) interim restorations, stainless steel (SS) bands, GIC dome overlays and GIC dome overlays with occlusal temporary restorations. The root canals of 92 extracted human premolars and molars were prepared with rotary NiTi instruments and dressed with calcium hydroxide paste prior to cavity preparation for standardized MOD restorations. Teeth were divided into four groups (n = 23) and temporarily restored with: GIC interim restorations (GIC group), stainless steel bands (SS group), GIC dome overlays (GIC-O group) or GIC dome overlays with intermediate restorative material (IRM) in the access cavities (GIC-IRM group). Teeth were subjected to compressive axial load until fracture; fracture forces and fracture modes were recorded. Statistical analysis included Kaplan-Meier plots, Cox proportional hazards model, one-way analysis of variance, chi-square and Fisher's exact tests. There was a significantly higher risk of failure in the GIC group compared with the SS (P < 0.001), GIC-O (P < 0.001) and GIC-IRM (P = 0.001) groups. The mean fracture force for SS was significantly higher than GIC-O (P = 0.03) and GIC-IRM (P < 0.001). GIC fracture force was significantly lower than all other groups (P < 0.001). Significantly fewer unfavourable fractures were observed in SS compared with GIC (P = 0.001), GIC-O (P = 0.007) and GIC-IRM (P < 0.001). Glass-ionomer cement dome overlays with reduced cuspal height and occlusal inclines may be recommended for broken-down posterior teeth, without any risk of poor aesthetics, gingival irritation or further proximal tooth structure loss. Stainless steel bands may only need to be used in extensively broken-down teeth or in the presence of parafunctional habits. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Evaluation of the AISI 904L Alloy Weld Overlays Obtained by GMAW and Electro-Slag Welding Processes

NASA Astrophysics Data System (ADS)

Jorge, Jorge C. F.; Meira, O. G.; Madalena, F. C. A.; de Souza, L. F. G.; Araujo, L. S.; Mendes, M. C.

2017-05-01

The use of superaustenitic stainless steels (SASS) as an overlay replacement for nickel-based alloys can be an interesting alternative for the oil and gas industries, due to its lower cost, when compared to superalloys. Usually, the deposition is made with several welding passes by using conventional arc welding processes, such as gas tungsten arc welding (GTAW) or gas metal arc welding (GMAW) processes. In this respect, electro-slag welding (ESW), which promotes high heat inputs and low dilution of the welds, can also be attractive for this application, as it provides a higher productivity, once only one layer is needed for the deposition of the minimum thickness required. The present work evaluates the behavior of an AISI 904L SASS weld overlay deposited on a carbon steel ASTM A516 Grade 70 by ESW and GMAW processes. Both as-welded and heat-treated conditions were evaluated and compared. A multipass welding by GMAW process with three layers and 48 passes was performed on 12.5 × 200 × 250 mm steel plates with average welding energy of 1.0 kJ/mm. For ESW process, only one layer was deposited on 50 × 400 × 400 mm steel plates with average welding energy of 11.7 kJ/mm. After welding, a post-weld heat treatment (PWHT) at 620 °C for 10 h was performed in half of the steel plate, in order to allow the comparison between this condition and the as-welded one. For both processes, the austenitic microstructure of the weld deposits was characterized by optical microscopy and scanning electron microscopy with electron backscatter diffraction. A low proportion of secondary phases were observed in all conditions, and the PWHT did not promote significant changes on the hardness profile. Martensite for GMAW process and bainite for ESW process were the microstructural constituents observed at the coarse grain heat-affected zone, due to the different cooling rates. For ESW process, no evidences of partially diluted zones were found. As a consequence of the microstructural

Colored Overlays Enhance Visual Perceptual Performance in Children with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Ludlow, A. K.; Wilkins, A. J.; Heaton, P.

2008-01-01

Children with autism spectrum disorders (ASD), together with controls matched for age and ability participated in three experiments that assessed the therapeutic benefit of colored overlays. The findings from the first experiment showed that a significantly greater proportion of children with ASD, than controls, increased reading speed when using…

The Corrosion and Corrosion Fatigue Behavior of Nickel Based Alloy Weld Overlay and Coextruded Claddings

NASA Astrophysics Data System (ADS)

Stockdale, Andrew

The use of low NOx boilers in coal fired power plants has resulted in sulfidizing corrosive conditions within the boilers and a reduction in the service lifetime of the waterwall tubes. As a solution to this problem, Ni-based weld overlays are used to provide the necessary corrosion resistance however; they are susceptible to corrosion fatigue. There are several metallurgical factors which give rise to corrosion fatigue that are associated with the localized melting and solidification of the weld overlay process. Coextruded coatings offer the potential for improved corrosion fatigue resistance since coextrusion is a solid state coating process. The corrosion and corrosion fatigue behavior of alloy 622 weld overlays and coextruded claddings was investigated using a Gleeble thermo-mechanical simulator retrofitted with a retort. The experiments were conducted at a constant temperature of 600°C using a simulated combustion gas of N2-10%CO-5%CO2-0.12%H 2S. An alternating stress profile was used with a minimum tensile stress of 0 MPa and a maximum tensile stress of 300 MPa (ten minute fatigue cycles). The results have demonstrated that the Gleeble can be used to successfully simulate the known corrosion fatigue cracking mechanism of Ni-based weld overlays in service. Multilayer corrosion scales developed on each of the claddings that consisted of inner and outer corrosion layers. The scales formed by the outward diffusion of cations and the inward diffusion of sulfur and oxygen anions. The corrosion fatigue behavior was influenced by the surface finish and the crack interactions. The initiation of a large number of corrosion fatigue cracks was not necessarily detrimental to the corrosion fatigue resistance. Finally, the as-received coextruded cladding exhibited the best corrosion fatigue resistance.

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

PubMed

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.

Condition of concrete overlays on Route 60 over Lynnhaven Inlet after 10 years.

DOT National Transportation Integrated Search

2009-01-01

In 1996, 16 high performance concrete overlays were placed on two 28-span bridges on Route 60 over the Lynnhaven Inlet in Virginia Beach, Virginia. Thirteen concrete mixtures included a variety of combinations of silica fume (SF), fly ash, slag, late...

New overlay measurement technique with an i-line stepper using embedded standard field image alignment marks for wafer bonding applications

NASA Astrophysics Data System (ADS)

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

2017-06-01

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 require addition backside processing of the wafer; thus an accurate alignment between the front and backside of the wafer is mandatory. 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]. Therefore, the available overlay measurement techniques are not suitable if overlay and alignment marks are realized at the bonding interface of a wafer stack which consists of both a silicon device and a silicon carrier wafer. The former used EVG 40NT automated overlay measurement system, which use two opposite positioned microscopes inspecting simultaneous the wafer back and front side, is not capable measuring embedded overlay

Computational overlay metrology with adaptive data analytics

NASA Astrophysics Data System (ADS)

Schmitt-Weaver, Emil; Subramony, Venky; Ullah, Zakir; Matsunobu, Masazumi; Somasundaram, Ravin; Thomas, Joel; Zhang, Linmiao; Thul, Klaus; Bhattacharyya, Kaustuve; Goossens, Ronald; Lambregts, Cees; Tel, Wim; de Ruiter, Chris

2017-03-01

With photolithography as the fundamental patterning step in the modern nanofabrication process, every wafer within a semiconductor fab will pass through a lithographic apparatus multiple times. With more than 20,000 sensors producing more than 700GB of data per day across multiple subsystems, the combination of a light source and lithographic apparatus provide a massive amount of information for data analytics. This paper outlines how data analysis tools and techniques that extend insight into data that traditionally had been considered unmanageably large, known as adaptive analytics, can be used to show how data collected before the wafer is exposed can be used to detect small process dependent wafer-towafer changes in overlay.

The Molecular Volcano Revisited: Determination of Crack Propagation and Distribution During the Crystallization of Nanoscale Amorphous Solid Water Films.

DOE Office of Scientific and Technical Information (OSTI.GOV)

May, Robert A.; Smith, R. Scott; Kay, Bruce D.

2012-02-02

Temperature programmed desorption (TPD) is utilized to determine the length distribution of cracks formed through amorphous solid water (ASW) during crystallization. This distribution is determined by monitoring how the thickness of an ASW overlayer alters desorption of an underlayer of O2. As deposited the ASW overlayer prevents desorption of O2. During crystallization, cracks form through the ASW overlayer and open a path to vacuum which allows O2 to escape in a rapid episodic release known as the 'molecular volcano'. Sufficiently thick ASW overlayers further trap O2 resulting in a second O2 desorption peak commensurate with desorption of the last ofmore » the ASW overlayer. The evolution of this trapping peak with overlayer thickness is the basis for determining the distribution of crystallization induced cracks through the ASW. Reflection adsorption infrared spectroscopy (RAIRS) and TPD of multicomponent parfait structures of ASW, O2 and Kr indicate that a preponderance of these cracks propagate down from the outer surface of the ASW.« less

Assessment of in-situ compaction degree of HMA pavement surface layers using GPR and novel dielectric properties-based algorithms

NASA Astrophysics Data System (ADS)

Georgiou, Panos; Loizos, Fokion

2015-04-01

Field compaction of asphalt pavements is ultimately conducted to achieve layer(s) with suitable mechanical stability. However, the achieved degree of compaction has a significant influence on the performance of asphalt pavements. Providing all desirable mixture design characteristics without adequate compaction could lead to premature permanent deformation, excessive aging, and moisture damage; these distresses reduce the useful life of asphalt pavements. Hence, proper construction of an asphalt pavement is necessary to develop a long lasting roadway that will help minimize future maintenance. This goal is achieved by verifying and confirming that design specifications, in this case density specifications are met through the use of Quality Assurance (QA) practices. With respect to in-situ compaction degree of hot mix asphalt (HMA) pavement surface layers, nearly all agencies specify either cored samples or nuclear/ non nuclear density gauges to provide density measurement of the constructed pavement. Typically, a small number of spot tests (with either cores or nuclear gauges) are run and a judgment about the density level of the entire roadway is made based on the results of this spot testing. Unfortunately, density measurement from a small number of spots may not be representative of the density of the pavement mat. Hence, full coverage evaluation of compaction quality of the pavement mat is needed. The Ground Penetrating Radar (GPR), as a Non Destructive Testing (NDT) technique, is an example of a non-intrusive technique that favors over the methods mentioned above for assessing compaction quality of asphalt pavements, since it allows measurement of all mat areas. Further, research studies in recent years have shown promising results with respect to its capability, coupled with the use of novel algorithms based on the dielectric properties of HMA, to predict the in-situ field density. In view of the above, field experimental surveys were conducted to assess the

A Reference Implementation of the OGC CSW EO Standard for the ESA HMA-T project

NASA Astrophysics Data System (ADS)

Bigagli, Lorenzo; Boldrini, Enrico; Papeschi, Fabrizio; Vitale, Fabrizio

2010-05-01

This work was developed in the context of the ESA Heterogeneous Missions Accessibility (HMA) project, whose main objective is to involve the stakeholders, namely National space agencies, satellite or mission owners and operators, in an harmonization and standardization process of their ground segment services and related interfaces. Among HMA objectives was the specification, conformance testing, and experimentation of two Extension Packages (EPs) of the ebRIM Application Profile (AP) of the OGC Catalog Service for the Web (CSW) specification: the Earth Observation Products (EO) EP (OGC 06-131) and the Cataloguing of ISO Metadata (CIM) EP (OGC 07-038). Our contributions have included the development and deployment of Reference Implementations (RIs) for both the above specifications, and their integration with the ESA Service Support Environment (SSE). The RIs are based on the GI-cat framework, an implementation of a distributed catalog service, able to query disparate Earth and Space Science data sources (e.g. OGC Web Services, Unidata THREDDS) and to expose several standard interfaces for data discovery (e.g. OGC CSW ISO AP). Following our initial planning, the GI-cat framework has been extended in order to expose the CSW.ebRIM-CIM and CSW.ebRIM-EO interfaces, and to distribute queries to CSW.ebRIM-CIM and CSW.ebRIM-EO data sources. We expected that a mapping strategy would suffice for accommodating CIM, but this proved to be unpractical during implementation. Hence, a model extension strategy was eventually implemented for both the CIM and EO EPs, and the GI-cat federal model was enhanced in order to support the underlying ebRIM AP. This work has provided us with new insights into the different data models for geospatial data, and the technologies for their implementation. The extension is used by suitable CIM and EO profilers (front-end mediator components) and accessors (back-end mediator components), that relate ISO 19115 concepts to EO and CIM ones. Moreover

Thermo-Mechanical Analysis of a Single-Pass Weld Overlay and Girth Welding in Lined Pipe

NASA Astrophysics Data System (ADS)

Obeid, Obeid; Alfano, Giulio; Bahai, Hamid

2017-08-01

The paper presents a nonlinear heat-transfer and mechanical finite-element (FE) analyses of a two-pass welding process of two segments of lined pipe made of a SUS304 stainless steel liner and a C-Mn steel pipe. The two passes consist of the single-pass overlay welding (inner lap weld) of the liner with the C-Mn steel pipe for each segment and the single-pass girth welding (outer butt weld) of the two segments. A distributed power density of the moving welding torch and a nonlinear heat-transfer coefficient accounting for both radiation and convection have been used in the analysis and implemented in user subroutines for the FE code ABAQUS. The modeling procedure has been validated against previously published experimental results for stainless steel and carbon steel welding separately. The model has been then used to determine the isotherms induced by the weld overlay and the girth welding and to clarify their influence on the transient temperature field and residual stress in the lined pipe. Furthermore, the influence of the cooling time between weld overlay and girth welding and of the welding speed have been examined thermally and mechanically as they are key factors that can affect the quality of lined pipe welding.

Restoration of the Occlusal Vertical Dimension with an Overlay Removable Partial Denture: A Clinical Report.

PubMed

Zanardi, Piero Rocha; Santos, Mayara Silva; Stegun, Roberto Chaib; Sesma, Newton; Costa, Bruno; Laganá, Dalva Cruz

2016-10-01

The process of tooth loss throughout life associated with severe occlusal wear may pose a challenge in the rehabilitation of partially edentulous arches. In these cases, many therapeutic procedures are necessary because each tooth must be restored to obtain the correct anatomical contour and recover the occlusal vertical dimension (OVD). A removable partial denture (RPD) with occlusal/incisal coverage, also known as an overlay RPD, is an alternative treatment option with fewer interventions, and, consequently, lower cost. This clinical report reviews the principles involved in the clinical indication for an overlay RPD, as well as the necessary planning and execution, to discuss the feasibility and clinical effectiveness of this treatment, identifying the indications, advantages, and disadvantages of this procedure through the presentation of a clinical case. The overlay RPD can be an alternative treatment for special situations involving partially edentulous arches in patients who need reestablishment of the OVD and/or realignment of the occlusal plane, and it can be used as a temporary or definitive treatment. The main advantages of this type of treatment are its simplicity, reversibility, and relatively low cost; however, further studies are needed to ensure the efficacy of this treatment option. © 2015 by the American College of Prosthodontists.

Technical advisory guide (TAG) for bonded wearing course pilot projects.

DOT National Transportation Integrated Search

2003-10-01

A bonded wearing course (BWC) is a gap graded, ultra thin hot-mix asphalt (HMA) mixture applied : over a thick polymer modified asphalt emulsion membrane. The emulsion membrane seals the : existing surface and produces high binder content at the inte...

New relationship between fundamental site frequency and thickness of soft sediments from seismic ambient noise

NASA Astrophysics Data System (ADS)

Abd el-aal, Abd el-aziz Khairy

2018-05-01

In this contribution, new relationship between the fundamental site frequency and the thickness of soft sediments is obtained for many sites in Egypt. The Horizontal-to-Vertical Spectral Ratio ("H/V") technique (known as Nakamura technique) can be used as a robust tool to determine the thickness of soft sediments layers overlaying bedrock from observations and measurements of seismic ambient noise data. In Egypt, numerous seismic ambient noise measurements have been conducted in several areas to determine the dynamic properties of soft soil for engineering purposes. At each site in each studied area, the fundamental site frequency was accurately estimated from the main peak in the spectral ratio between the horizontal and vertical component. Consequently, an extensive database of microtremor measurements, well logging data, and shallow seismic refraction data have been configured and assembled for the studied areas. New formula between fundamental site frequency (f 0 ) and thickness of soft sediments (h) is established. The new formula has been validated and compared with other formulas of earlier scientists, and the results indicate that the calculated depth and geometry of the bedrock surface using new formula are in a good agreement with well logs data and previously published seismic refraction surveys in the investigated sites.

On-product overlay enhancement using advanced litho-cluster control based on integrated metrology, ultra-small DBO targets and novel corrections

NASA Astrophysics Data System (ADS)

Bhattacharyya, Kaustuve; Ke, Chih-Ming; Huang, Guo-Tsai; Chen, Kai-Hsiung; Smilde, Henk-Jan H.; Fuchs, Andreas; Jak, Martin; van Schijndel, Mark; Bozkurt, Murat; van der Schaar, Maurits; Meyer, Steffen; Un, Miranda; Morgan, Stephen; Wu, Jon; Tsai, Vincent; Liang, Frida; den Boef, Arie; ten Berge, Peter; Kubis, Michael; Wang, Cathy; Fouquet, Christophe; Terng, L. G.; Hwang, David; Cheng, Kevin; Gau, TS; Ku, Y. C.

2013-04-01

Aggressive on-product overlay requirements in advanced nodes are setting a superior challenge for the semiconductor industry. This forces the industry to look beyond the traditional way-of-working and invest in several new technologies. Integrated metrology2, in-chip overlay control, advanced sampling and process correction-mechanism (using the highest order of correction possible with scanner interface today), are a few of such technologies considered in this publication.

Ductile film delamination from compliant substrates using hard overlayers

PubMed Central

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

2014-01-01

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. PMID:25641995

Ductile film delamination from compliant substrates using hard overlayers.

PubMed

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.

Efforts to reduce reflective cracking of bituminous concrete overlays of Portland cement concrete pavements.

DOT National Transportation Integrated Search

1975-01-01

Studies of efforts in Virginia to reduce the incidence of reflection cracking when portland cement concrete pavements or bases are overlayed with asphaltic concrete are reported. The methods of reflection crack reduction discussed are: (1) The use of...

Investigation into shrinkage of high-performance concrete used for Iowa bridge decks and overlays.

DOT National Transportation Integrated Search

2013-09-01

High-performance concrete (HPC) overlays have been used increasingly as an effective and economical method for bridge decks in Iowa and other states. However, due to its high cementitious material content, HPC often displays high shrinkage cracking p...

The Effects of a Dynamic Spectrum Access Overlay in LTE-Advanced Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Juan D. Deaton; Ryan E. lrwin; Luiz A. DaSilva

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 andmore » 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.« less

Challenges of image placement and overlay at the 90-nm and 65-nm nodes

NASA Astrophysics Data System (ADS)

Trybula, Walter J.

2003-05-01

The technology acceleration of the ITRS Roadmap has many implications on both the semiconductor supplier community and the manufacturers. INTERNATIONAL SE-MATECH has been leading and supporting efforts to investigate the impact of the tech-nology introduction. This paper examines the issue of manufacturing tolerances available for image placement on adjacent critical levels (overlay) at the 90nm and 65nm technol-ogy nodes. The allowable values from the 2001 release of the ITRS Roadmap are 32nm for the 90nm node, and 23nm for the 65nm node. Even the 130nm node has overlay requirements of only 46nm. Employing tolerances that can be predicted, the impact of existing production/processing tolerance accumulation can provide an indication of the challenges facing the manufacturer in the production of 90nm and 65nm Node devices.

Cast titanium overlay denture for a geriatric patient with a reduced vertical dimension.

PubMed

Guttal, Satyabodh; Patil, Narendra P

2005-12-01

An older patient reporting to the dental surgery for his/her dental treatment is becoming a common occurrence. Improved oral hygiene has meant that teeth are retained for a longer time, along with the potential problems of attrition, decreased vertical dimension, temporomandibular joint discomfort/strain, and poor aesthetics. The case in question is that of a 65-year-old male patient who had severe attrition in the lower arch, temporomandibular joint pain and reduced vertical dimension. The maxillary arch had previously been restored with a fixed partial prosthesis. For restoration of the lower teeth, a removable cast titanium overlay denture was fabricated incorporating an increased vertical dimension. Porcelain facings were placed to restore the aesthetics of the anterior teeth. The titanium was cast in a semi-automatic electric arc, pressure type casting machine. A titanium overlay denture with porcelain facing on the anterior teeth may provide a means of restoring a patient's concerns regarding aesthetics and function.

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

DOT National Transportation Integrated Search

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...

Evaluation of thin epoxy system overlays for concrete bridge decks : interim report No. 1.

DOT National Transportation Integrated Search

1986-05-01

Four epoxy overlay systems were applied to concrete bridge decks in north Louisiana to evaluate their performance as skid resistant surfaces primarily and also as concrete sealers. Dural Flexolith, Poly-Carb Flexogrid, and Con/Chem Cono/Crete were pl...

Design of ultra high performance concrete as an overlay in pavements and bridge decks.

DOT National Transportation Integrated Search

2014-08-01

The main objective of this research was to develop ultra-high performance concrete (UHPC) as a reliable, economic, low carbon foot : print and durable concrete overlay material that can offer shorter traffic closures due to faster construction. The U...

Construction and performance of ultra thin asphalt friction course

DOT National Transportation Integrated Search

1997-09-01

The Novachip process, also known as ultrathin friction course, was developed in France in 1986. The process utilizes a single piece of equipment to place a thin, gap-graded hot mix asphalt (HMA) onto a relatively thick layer of polymer modified aspha...

Development of an improved overlay design procedure for Oregon : volume II, evaluation of procedure.

DOT National Transportation Integrated Search

1987-12-01

This report is the second in a three-volume series dealing with the development of an improved overlay design procedure for Oregon. This report presents the results of the second-year findings. Data from five projects were collected and analyzed usin...

Environmental influence on the bond between a polymer concrete overlay and an aluminum substrate.

DOT National Transportation Integrated Search

2000-04-01

Chloride-ion-induced corrosion of reinforcing steel in concrete bridge decks has become a major problem in the United States. : Latex-modified concrete, low-slump dense concrete, and hot-mix asphalt membrane overlays are some of the most used : rehab...

Evaluation of the SafeLane overlay system for crash reduction on bridge deck surfaces.

DOT National Transportation Integrated Search

2010-03-01

The winter performance of the SafeLane commercial overlay system has been evaluated at four installations on : bridge decks in the state of Minnesota. The study was conducted over a period of a total of three years. Analyses : included mechanical ...

First-principles study of nitric oxide oxidation on Pt(111) versus Pt overlayer on 3d transition metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arevalo, Ryan Lacdao; Escaño, Mary Clare Sison; Kasai, Hideaki, E-mail: kasai@dyn.ap.eng.osaka-u.ac.jp

2015-03-15

Catalytic oxidation of NO to NO{sub 2} is a significant research interest for improving the quality of air through exhaust gas purification systems. In this paper, the authors studied this reaction on pure Pt and Pt overlayer on 3d transition metals using kinetic Monte Carlo simulations coupled with density functional theory based first principles calculations. The authors found that on the Pt(111) surface, NO oxidation proceeds via the Eley–Rideal mechanism, with O{sub 2} dissociative adsorption as the rate-determining step. The oxidation path via the Langmuir–Hinshelwood mechanism is very slow and does not significantly contribute to the overall reaction. However, inmore » the Pt overlayer systems, the oxidation of NO on the surface is more thermodynamically and kinetically favorable compared to pure Pt. These findings are attributed to the weaker binding of O and NO on the Pt overlayer systems and the binding configuration of NO{sub 2} that promotes easier N-O bond formation. These results present insights for designing affordable and efficient catalysts for NO oxidation.« less

Automatic Generation of Overlays and Offset Values Based on Visiting Vehicle Telemetry and RWS Visuals

NASA Technical Reports Server (NTRS)

Dunne, Matthew J.

2011-01-01

The development of computer software as a tool to generate visual displays has led to an overall expansion of automated computer generated images in the aerospace industry. These visual overlays are generated by combining raw data with pre-existing data on the object or objects being analyzed on the screen. The National Aeronautics and Space Administration (NASA) uses this computer software to generate on-screen overlays when a Visiting Vehicle (VV) is berthing with the International Space Station (ISS). In order for Mission Control Center personnel to be a contributing factor in the VV berthing process, computer software similar to that on the ISS must be readily available on the ground to be used for analysis. In addition, this software must perform engineering calculations and save data for further analysis.

Asphalt Overlay Design Methods for Rigid Pavements Considering Rutting, Reflection Cracking, and Fatigue Cracking

DOT National Transportation Integrated Search

1998-10-01

The overall objectives of this study were (1) to provide basic performance evaluation of asphalt overlays on rigid pavements and (2) to provide a design tool for supporting a long-range rehabilitation plan for the US 59 : corridor in the Lufkin Distr...

Comparing the capitalisation benefits of light-rail transit and overlay zoning for single-family houses and condos by neighbourhood type in metropolitan Phoenix, Arizona.

PubMed

Atkinson-Palombo, Carol

2010-01-01

Light rail transit (LRT) is increasingly accompanied by overlay zoning which specifies the density and type of future development to encourage landscapes conducive to transit use. Neighbourhood type (based on land use mix) is used to partition data and investigate how pre-existing land use, treatment with a park-and-ride (PAR) versus walk-and-ride (WAR) station and overlay zoning interrelate. Hedonic models estimate capitalisation effects of LRT-related accessibility and overlay zoning on single-family houses and condos in different neighbourhoods for the system in metropolitan Phoenix, Arizona. Impacts differ by housing and neighbourhood type. Amenity-dominated mixed-use neighbourhoods-predominantly WAR communities-experience premiums of 6 per cent for single-family houses and over 20 per cent for condos, the latter boosted an additional 37 per cent by overlay zoning. Residential neighbourhoods-predominantly PAR communities-experience no capitalisation benefits for single-family houses and a discount for condos. The results suggest that land use mix is an important variable to select comparable neighbourhoods.

Effect of metrology time delay on overlay APC

NASA Astrophysics Data System (ADS)

Carlson, Alan; DiBiase, Debra

2002-07-01

The run-to-run control strategy of lithography APC is primarily composed of a feedback loop as shown in the diagram below. It is known that the insertion of a time delay in a feedback loop can cause degradation in control performance and could even cause a stable system to become unstable, if the time delay becomes sufficiently large. Many proponents of integrated metrology methods have cited the damage caused by metrology time delays as the primary justification for moving from a stand-alone to integrated metrology. While there is little dispute over the qualitative form of this argument, there has been very light published about the quantitative effects under real fab conditions - precisely how much control is lost due to these time delays. Another issue regarding time delays is that the length of these delays is not typically fixed - they vary from lot to lot and in some cases this variance can be large - from one hour on the short side to over 32 hours on the long side. Concern has been expressed that the variability in metrology time delays can cause undesirable dynamics in feedback loops that make it difficult to optimize feedback filters and gains and at worst could drive a system unstable. By using data from numerous fabs, spanning many sizes and styles of operation, we have conducted a quantitative study of the time delay effect on overlay run- to-run control. Our analysis resulted in the following conclusions: (1) There is a significant and material relationship between metrology time delay and overlay control under a variety of real world production conditions. (2) The run-to-run controller can be configured to minimize sensitivity to time delay variations. (3) The value of moving to integrated metrology can be quantified.

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

DOT National Transportation Integrated Search

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 ...

Arbitration Intervention Worker (AIW) Services: Case Management Overlay in a Juvenile Diversion Program

ERIC Educational Resources Information Center

Poythress, Norman G.; Dembo, Richard; DuDell, Gary; Wareham, Jennifer

2006-01-01

In this issue we describe a clinical trials study of the impact of adding specific case manager overlay services to "treatment as usual" services for youths in a Juvenile Arbitration Program. In this first article we describe the experimental intervention, the Arbitration Intervention Worker (AIW) service, which was provided to a randomly selected…

Feed-forward alignment correction for advanced overlay process control using a standalone alignment station "Litho Booster"

NASA Astrophysics Data System (ADS)

Yahiro, Takehisa; Sawamura, Junpei; Dosho, Tomonori; Shiba, Yuji; Ando, Satoshi; Ishikawa, Jun; Morita, Masahiro; Shibazaki, Yuichi

2018-03-01

One of the main components of an On-Product Overlay (OPO) error budget is the process induced wafer error. This necessitates wafer-to-wafer correction in order to optimize overlay accuracy. This paper introduces the Litho Booster (LB), standalone alignment station as a solution to improving OPO. LB can execute high speed alignment measurements without throughput (THP) loss. LB can be installed in any lithography process control loop as a metrology tool, and is then able to provide feed-forward (FF) corrections to the scanners. In this paper, the detailed LB design is described and basic LB performance and OPO improvement is demonstrated. Litho Booster's extendibility and applicability as a solution for next generation manufacturing accuracy and productivity challenges are also outlined

Use of infrared thermography to detect thermal segregation in asphalt overlay and reflective cracking potential.

DOT National Transportation Integrated Search

2015-03-01

The objectives of this study were to assess whether temperature differentials measured using Infrared : Thermography (IRT) occur in an overlay built on top of discontinuities such as joints and cracks and to : study the horizontal and vertical therma...

Asphalt concrete overlays on CRCP : decision criteria, tack coat evaluation, and asphalt concrete mixture evaluation.

DOT National Transportation Integrated Search

2005-02-01

This report presents the research undertaken within two areas of study of thin asphalt concrete (AC) overlays to rehabilitate : continuously reinforced concrete pavements (CRCP). The first one is the development of a decision tree for the project : s...

Overlay coating degradation by simultaneous oxidation and coating/substrate interdiffusion. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Nesbitt, J. A.

1983-01-01

Degradation of NiCrAlZr overlay coatings on various NiCrAl substrates was examined after cyclic oxidation. Concentration/distance profiles were measured in the coating and substrate after various oxidation exposures at 1150 C. For each stubstrate, the Al content in the coating decreased rapidly. The concentration/distance profiles, and particularly that for Al, reflected the oxide spalling resistance of each coated substrate. A numerical model was developed to simulate diffusion associated with overlay-coating degradation by oxidation and coating/substrate interdiffusion. Input to the numerical model consisted of the Cr and Al content of the coating and substrate, ternary diffusivities, and various oxide spalling parameters. The model predicts the Cr and Al concentrations in the coating and substrate after any number of oxidation/thermal cycles. The numerical model also predicts coating failure based on the ability of the coating to supply sufficient Al to the oxide scale. The validity of the model was confirmed by comparison of the predicted and measured concentration/distance profiles. The model was subsequently used to identify the most critical system parameters affecting coating life.

Evaluation of high performance concrete overlays placed on Route 60 over Lynnhaven Inlet in Virginia.

DOT National Transportation Integrated Search

2000-08-01

Sixteen high performance concrete overlays were placed on two 28-span bridges on Route 60 over Lynnhaven Inlet in Virginia Beach, Virginia, in the spring of 1996. The construction was funded with 20 percent Virginia Department of Transportation maint...

Historical data learning based dynamic LSP routing for overlay IP/MPLS over WDM networks

NASA Astrophysics Data System (ADS)

Yu, Xiaojun; Xiao, Gaoxi; Cheng, Tee Hiang

2013-08-01

Overlay IP/MPLS over WDM network is a promising network architecture starting to gain wide deployments recently. A desirable feature of such a network is to achieve efficient routing with limited information exchanges between the IP/MPLS and the WDM layers. This paper studies dynamic label switched path (LSP) routing in the overlay IP/MPLS over WDM networks. To enhance network performance while maintaining its simplicity, we propose to learn from the historical data of lightpath setup costs maintained by the IP-layer integrated service provider (ISP) when making routing decisions. Using a novel historical data learning scheme for logical link cost estimation, we develop a new dynamic LSP routing method named Existing Link First (ELF) algorithm. Simulation results show that the proposed algorithm significantly outperforms the existing ones under different traffic loads, with either limited or unlimited numbers of optical ports. Effects of the number of candidate routes, add/drop ratio and the amount of historical data are also evaluated.

Smooth Upgrade of Existing Passive Optical Networks With Spectral-Shaping Line-Coding Service Overlay

NASA Astrophysics Data System (ADS)

Hsueh, Yu-Li; Rogge, Matthew S.; Shaw, Wei-Tao; Kim, Jaedon; Yamamoto, Shu; Kazovsky, Leonid G.

2005-09-01

A simple and cost-effective upgrade of existing passive optical networks (PONs) is proposed, which realizes service overlay by novel spectral-shaping line codes. A hierarchical coding procedure allows processing simplicity and achieves desired long-term spectral properties. Different code rates are supported, and the spectral shape can be properly tailored to adapt to different systems. The computation can be simplified by quantization of trigonometric functions. DC balance is achieved by passing the dc residual between processing windows. The proposed line codes tend to introduce bit transitions to avoid long consecutive identical bits and facilitate receiver clock recovery. Experiments demonstrate and compare several different optimized line codes. For a specific tolerable interference level, the optimal line code can easily be determined, which maximizes the data throughput. The service overlay using the line-coding technique leaves existing services and field-deployed fibers untouched but fully functional, providing a very flexible and economic way to upgrade existing PONs.

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).

DOT National Transportation Integrated Search

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...

Facile fabrication of ultrathin Pt overlayers onto nanoporous metal membranes via repeated Cu UPD and in situ redox replacement reaction.

PubMed

Liu, Pengpeng; Ge, Xingbo; Wang, Rongyue; Ma, Houyi; Ding, Yi

2009-01-06

Ultrathin Pt films from one to several atomic layers are successfully decorated onto nanoporous gold (NPG) membranes by utilizing under potential deposition (UPD) of Cu onto Au or Pt surfaces, followed by in situ redox replacement reaction (RRR) of UPD Cu by Pt. The thickness of Pt layers can be controlled precisely by repeating the Cu-UPD-RRR cycles. TEM observations coupled with electrochemical testing suggest that the morphology of Pt overlayers changes from an ultrathin epitaxial film in the case of one or two atomic layers to well-dispersed nanoislands in the case of four and more atomic layers. Electron diffraction (ED) patterns confirm that the as-prepared NPG-Pt membranes maintain a single-crystalline structure, even though the thickness of Pt films reaches six atomic layers, indicating the decorated Pt films hold the same crystallographic relationship to the NPG substrate during the entire fabrication process. Due to the regular modulation of Pt utilization, the electrocatalytic activity of NPG-Pt exhibits interesting surface structure dependence in methanol, ethanol, and CO electrooxidation reactions. These novel bimetallic nanocatalysts show excellent electrocatalytic activity and much enhanced poison tolerance as compared to the commercial Pt/C catalysts. The success in the fabrication of NPG-Pt-type materials provides a new path to prepare electrocatalysts with ultralow Pt loading and high Pt utilization, which is of great significance in energy-related applications, such as direct alcohol fuel cells (DAFCs).

Optical characterization of randomly microrough surfaces covered with very thin overlayers using effective medium approximation and Rayleigh-Rice theory

NASA Astrophysics Data System (ADS)

Ohlídal, Ivan; Vohánka, Jiří; Čermák, Martin; Franta, Daniel

2017-10-01

The modification of the effective medium approximation for randomly microrough surfaces covered by very thin overlayers based on inhomogeneous fictitious layers is formulated. The numerical analysis of this modification is performed using simulated ellipsometric data calculated using the Rayleigh-Rice theory. The system used to perform this numerical analysis consists of a randomly microrough silicon single crystal surface covered with a SiO2 overlayer. A comparison to the effective medium approximation based on homogeneous fictitious layers is carried out within this numerical analysis. For ellipsometry of the system mentioned above the possibilities and limitations of both the effective medium approximation approaches are discussed. The results obtained by means of the numerical analysis are confirmed by the ellipsometric characterization of two randomly microrough silicon single crystal substrates covered with native oxide overlayers. It is shown that the effective medium approximation approaches for this system exhibit strong deficiencies compared to the Rayleigh-Rice theory. The practical consequences implied by these results are presented. The results concerning the random microroughness are verified by means of measurements performed using atomic force microscopy.

Implant-retained mandibular bar-supported overlay dentures: a finite element stress analysis of four different bar heights.

PubMed

Rismanchian, Mansoor; Dakhilalian, Mansour; Bajoghli, Farshad; Ghasemi, Ehsan; Sadr-Eshkevari, Pooyan

2012-04-01

Proper stress distribution on dental implants is necessary in bar-retained implant overlay dentures. We aimed to comparatively assess this stress distribution according to different bar heights using finite element models. A three-dimensional (3D) computer model of mandible with 2 implants (ITI, 4.1 mm diameter and 12 mm length) in canine areas and an overlying implant-supported bar-retained overlay denture were simulated with 0-, 1-, 2-, and 3-mm bar heights using ABAQUS software. A vertical force was applied to the left first molar and gradually increased from 0 to 50 N. The resultant stress distribution was evaluated. Bars of 1 and 2 mm in height transferred the least stress to the implants (3.882 and 3.896 MPa, respectively). The 0-mm height of the bar connection transferred the highest stress value (4.277 MPa). The amount of stress transferred by 3-mm heights of the bar connection was greater than that of 1- and 2-mm bar connections and smaller than that of 0-mm bar connection (4.165 kgN). This 3D finite element analysis study suggested that the use of Dolder bar attachment with 1- and 2-mm heights could be associated with appropriate stress distribution for implant-retained overlay dentures.

Control of reflection cracking in a fabric-reinforced overlay on jointed portland cement concrete pavement.

DOT National Transportation Integrated Search

1982-01-01

A study of the installation and three-year performance evaluation of a fabric-reinforced bituminous concrete overlay of a jointed concrete pavement is reported. The fabric, a polypropylene in an asphaltic mastic, was shown to act as a significant det...

Evaluation of latex-modified and silica fume concrete overlays placed on six bridges in Virginia.

DOT National Transportation Integrated Search

2000-08-01

Latex-modified and silica fume concrete overlays were placed on six bridges on I-95 south of Emporia, Virginia, in the fall of 1994. The construction was funded with 20% Virginia Department of Transportation maintenance funds and 80% special ISTEA Se...

Bayesian networks in overlay recipe optimization

NASA Astrophysics Data System (ADS)

Binns, Lewis A.; Reynolds, Greg; Rigden, Timothy C.; Watkins, Stephen; Soroka, Andrew

2005-05-01

Currently, overlay measurements are characterized by "recipe", which defines both physical parameters such as focus, illumination et cetera, and also the software parameters such as algorithm to be used and regions of interest. Setting up these recipes requires both engineering time and wafer availability on an overlay tool, so reducing these requirements will result in higher tool productivity. One of the significant challenges to automating this process is that the parameters are highly and complexly correlated. At the same time, a high level of traceability and transparency is required in the recipe creation process, so a technique that maintains its decisions in terms of well defined physical parameters is desirable. Running time should be short, given the system (automatic recipe creation) is being implemented to reduce overheads. Finally, a failure of the system to determine acceptable parameters should be obvious, so a certainty metric is also desirable. The complex, nonlinear interactions make solution by an expert system difficult at best, especially in the verification of the resulting decision network. The transparency requirements tend to preclude classical neural networks and similar techniques. Genetic algorithms and other "global minimization" techniques require too much computational power (given system footprint and cost requirements). A Bayesian network, however, provides a solution to these requirements. Such a network, with appropriate priors, can be used during recipe creation / optimization not just to select a good set of parameters, but also to guide the direction of search, by evaluating the network state while only incomplete information is available. As a Bayesian network maintains an estimate of the probability distribution of nodal values, a maximum-entropy approach can be utilized to obtain a working recipe in a minimum or near-minimum number of steps. In this paper we discuss the potential use of a Bayesian network in such a capacity

Enabling optical metrology on small 5×5μm2 in-cell targets to support flexible sampling and higher order overlay and CD control for advanced logic devices nodes

NASA Astrophysics Data System (ADS)

Salerno, Antonio; de la Fuente, Isabel; Hsu, Zack; Tai, Alan; Chang, Hammer; McNamara, Elliott; Cramer, Hugo; Li, Daoping

2018-03-01

In next generation Logic devices, overlay control requirements shrink to sub 2.5nm level on-product overlay. Historically on-product overlay has been defined by the overlay capability of after-develop in-scribe targets. However, due to design and dimension, the after development metrology targets are not completely representative for the final overlay of the device. In addition, they are confined to the scribe-lane area, which limits the sampling possibilities. To address these two issues, metrology on structures matching the device structure and which can be sampled with high density across the device is required. Conventional after-etch CDSEM techniques on logic devices present difficulties in discerning the layers of interest, potential destructive charging effects and finally, they are limited by the long measurement times[1] [2] [3] . All together, limit the sampling densities and making CDSEM less attractive for control applications. Optical metrology can overcome most of these limitations. Such measurement, however, does require repetitive structures. This requirement is not fulfilled by logic devices, as the features vary in pitch and CD over the exposure field. The solution is to use small targets, with a maximum pad size of 5x5um2 , which can easily be placed in the logic cell area. These targets share the process and architecture of the device features of interest, but with a modified design that replicates as close as possible the device layout, allowing for in-device metrology for both CD and Overlay. This solution enables measuring closer to the actual product feature location and, not being limited to scribe-lanes, it opens the possibility of higher-density sampling schemes across the field. In summary, these targets become the facilitator of in-device metrology (IDM), that is, enabling the measurements both in-device Overlay and the CD parameters of interest and can deliver accurate, high-throughput, dense and after-etch measurements for Logic

Spectral evolution with incremental nanocoating of long period fiber gratings

NASA Astrophysics Data System (ADS)

Del Villar, Ignacio; Corres, Jesus M.; Achaerandio, Miguel; Arregui, Francisco J.; Matias, Ignacio R.

2006-12-01

The incremental deposition of a thin overlay on the cladding of a long-period fiber grating (LPFG) induces important resonance wavelength shifts in the transmission spectrum. The phenomenon is proved theoretically with a vectorial method based on hybrid modes and coupled mode theory, and experimentally with electrostatic self-assembly monolayer process. The phenomenon is repeated periodically for specific overlay thickness values with the particularity that the shape of the resonance wavelength shift depends on the thickness of the overlay. The main applications are the design of wide optical filters and multiparameter sensing devices.

Bandwidth auction for SVC streaming in dynamic multi-overlay

NASA Astrophysics Data System (ADS)

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.

Assessing the Crossdisciplinarity of Technology-Enhanced Learning with Science Overlay Maps and Diversity Measures

ERIC Educational Resources Information Center

Kalz, Marco; Specht, Marcus

2014-01-01

This paper deals with the assessment of the crossdisciplinarity of technology-enhanced learning (TEL). Based on a general discussion of the concept interdisciplinarity and a summary of the discussion in the field, two empirical methods from scientometrics are introduced and applied. Science overlay maps and the Rao-Stirling diversity index are…

Notation system and overlay diagrams for the analysis of paced electrocardiograms.

PubMed

Bernstein, A D; Parsonnet, V

1983-01-01

With the advent of adaptive dual-chamber pacing, the interaction between the pacemaker and the heart is becoming increasingly complex and the interpretation of paced electrocardiograms more difficult. We have developed a set of notation conventions for use in teaching and rhythm-strip analysis. Easily-drawn symbols delineate successful, unsuccessful, and inhibited pacing and sensing events as well as refractory and blanking periods. Another application is to generate movable transparent overlays after programming a pacemaker, to be used in interpreting subsequent rhythm strips.

Enhanced Performance of Field-Effect Transistors Based on Black Phosphorus Channels Reduced by Galvanic Corrosion of Al Overlayers.

PubMed

Lee, Sangik; Yoon, Chansoo; Lee, Ji Hye; Kim, Yeon Soo; Lee, Mi Jung; Kim, Wondong; Baik, Jaeyoon; Jia, Quanxi; Park, Bae Ho

2018-06-06

Two-dimensional (2D)-layered semiconducting materials with considerable band gaps are emerging as a new class of materials applicable to next-generation devices. Particularly, black phosphorus (BP) is considered to be very promising for next-generation 2D electrical and optical devices because of its high carrier mobility of 200-1000 cm 2 V -1 s -1 and large on/off ratio of 10 4 to 10 5 in field-effect transistors (FETs). However, its environmental instability in air requires fabrication processes in a glovebox filled with nitrogen or argon gas followed by encapsulation, passivation, and chemical functionalization of BP. Here, we report a new method for reduction of BP-channel devices fabricated without the use of a glovebox by galvanic corrosion of an Al overlayer. The reduction of BP induced by an anodic oxidation of Al overlayer is demonstrated through surface characterization of BP using atomic force microscopy, Raman spectroscopy, and X-ray photoemission spectroscopy along with electrical measurement of a BP-channel FET. After the deposition of an Al overlayer, the FET device shows a significantly enhanced performance, including restoration of ambipolar transport, high carrier mobility of 220 cm 2 V -1 s -1 , low subthreshold swing of 0.73 V/decade, and low interface trap density of 7.8 × 10 11 cm -2 eV -1 . These improvements are attributed to both the reduction of the BP channel and the formation of an Al 2 O 3 interfacial layer resulting in a high- k screening effect. Moreover, ambipolar behavior of our BP-channel FET device combined with charge-trap behavior can be utilized for implementing reconfigurable memory and neuromorphic computing applications. Our study offers a simple device fabrication process for BP-channel FETs with high performance using galvanic oxidation of Al overlayers.

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

NASA Astrophysics Data System (ADS)

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.

A field investigation of a concrete overlay containing silica fume on Route 50 over Opequon Creek.

DOT National Transportation Integrated Search

1993-01-01

This study evaluated concretes containing silica fume for use in overlays as a suitable alternative to the widely used latex-modified concrete (LMC). A two-lane, four-span bridge deck was overlaid with concrete containing silica fume at 7 percent or ...

Overlay removable denture for treatment of worn teeth.

PubMed

Beyth, Nurit; Tamari, Israel; Buller Sharon, Anat

2014-01-01

Rehabilitation of partially edentulous patients with excessively worn dentitions can be challenging. Factors including medical history as well as the cost of the treatment and patient wishes for simpler approaches must be considered. This manuscript describes the use of an overlay partial denture to treat patients with excessive wear of the maxillary teeth. We describe a technique to restore severely worn teeth using heat-cured acrylic as part of a partial or full denture. Minimal preparations of the teeth are required, and the restoration provides protection from further wear, and stabilizes the occlusion. This solution was functionally and esthetically suitable to the patients. The technique can be used in medically complex patients where extractions are contraindicated, such as post radiation therapy or bisphosphonate treatment. © 2014 Special Care Dentistry Association and Wiley Periodicals, Inc.

Image overlay navigation by markerless surface registration in gastrointestinal, hepatobiliary and pancreatic surgery.

PubMed

Sugimoto, Maki; Yasuda, Hideki; Koda, Keiji; Suzuki, Masato; Yamazaki, Masato; Tezuka, Tohru; Kosugi, Chihiro; Higuchi, Ryota; Watayo, Yoshihisa; Yagawa, Yohsuke; Uemura, Shuichiro; Tsuchiya, Hironori; Azuma, Takeshi

2010-09-01

We applied a new concept of "image overlay surgery" consisting of the integration of virtual reality (VR) and augmented reality (AR) technology, in which dynamic 3D images were superimposed on the patient's actual body surface and evaluated as a reference for surgical navigation in gastrointestinal, hepatobiliary and pancreatic surgery. We carried out seven surgeries, including three cholecystectomies, two gastrectomies and two colectomies. A Macintosh and a DICOM workstation OsiriX were used in the operating room for image analysis. Raw data of the preoperative patient information obtained via MDCT were reconstructed to volume rendering and projected onto the patient's body surface during the surgeries. For accurate registration, OsiriX was first set to reproduce the patient body surface, and the positional coordinates of the umbilicus, left and right nipples, and the inguinal region were fixed as physiological markers on the body surface to reduce the positional error. The registration process was non-invasive and markerlesss, and was completed within 5 min. Image overlay navigation was helpful for 3D anatomical understanding of the surgical target in the gastrointestinal, hepatobiliary and pancreatic anatomies. The surgeon was able to minimize movement of the gaze and could utilize the image assistance without interfering with the forceps operation, reducing the gap from the VR. Unexpected organ injury could be avoided in all procedures. In biliary surgery, the projected virtual cholangiogram on the abdominal wall could advance safely with identification of the bile duct. For early gastric and colorectal cancer, the small tumors and blood vessels, which usually could not be found on the gastric serosa by laparoscopic view, were simultaneously detected on the body surface by carbon dioxide-enhanced MDCT. This provided accurate reconstructions of the tumor and involved lymph node, directly linked with optimization of the surgical procedures. Our non

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

PubMed

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.

Development of an improved overlay design procedure for Oregon : vol. I, interim report, background and framework.

DOT National Transportation Integrated Search

1986-12-01

This report is the first in a three-volume series dealing with the development of an improved overlay design procedure for Oregon. This report presents the results of the first-year findings and includes: (1) a detailed review of the literature; (2) ...

An Appraisal of the Irlen Technique of Correcting Reading Disorders Using Tinted Overlays and Tinted Lenses.

ERIC Educational Resources Information Center

Solan, Harold A.

1990-01-01

The article reviews three studies (EC 600 064-066) evaluating the effectiveness of using Irlen tinted lenses or overlays with reading-disabled persons. It is concluded that carefully designed and controlled studies do not currently lend support to the Irlen hypothesis. (DB)

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

USDA-ARS?s Scientific Manuscript database

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...

Overlays or ceramic fragments for tooth restoration: an analysis of fracture resistance.

PubMed

Tavarez, Rudys Rodolfo de Jesus; Firoozmand, Leily Macedo; Silva, Mônica Barros; Malheiros, Adriana Santos; Bandéca, Matheus Coelho

2014-01-01

The aim of this study was to evaluate the mode of fracture and resistance of partial ceramic restorations of posterior teeth. Thirty healthy upper premolars were selected and divided into three groups (n = 10): Group 1- control, healthy unrestored teeth, group 2-teeth restored with ceramic fragments; and group 3-teeth restored with ceramic overlays. The restorations were manufactured with feldspathic ceramic and cemented with RelyX ARC resin cement. After being stored in distilled water for 7 days, the teeth were subjected to axial compression mechanical testing with a universal testing machine. Force was applied to the long axis of the tooth at a speed of 0.5 mm/min until fracture. The data were analyzed with one-way ANOVA and Tukey's test (5%). The mode of fracture was scored according to the degree of involvement of the tooth structure and the type of restoration. A significant difference (p < 0.05) was showed between groups 2 (1155 N) and 3 (846.6 N), but there was no significant difference between group 1 and the other groups (1046 N), More extensive fractures were prevalent in the healthy teeth group (Group 1), which had no occlusal coverage; less severe fractures were found in groups 2 and 3. We conclude that teeth restored with ceramic fragments may offer greater resistance to fractures compared to teeth that have overlay restorations.

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

PubMed Central

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

Fix it first : utilizing the seismic property analyzer and MMLS to develop guidelines for the use of polymer modified thin lift HMA vs. surface treatments.

DOT National Transportation Integrated Search

2012-09-01

The main objective of this study was to develop thin lift overlay mixtures with polymer modified asphalt for use in New England. As part of this : research a comprehensive literature review and internet survey was conducted. Moreover, laboratory test...

The migration law of overlay rock and coal in deeply inclined coal seam with fully mechanized top coal caving.

PubMed

Liu, Jian; Chen, Shan-Le; Wang, Hua-Jun; Li, Yu-Cheng; Geng, Xiaowei

2015-07-01

In a mine area, some environment geotechnics problems always occure, induced by mined-out region such as the subsidence and cracks at ground level, deformation and destruction of buildings, landslides destruction of water resources and the ecological environment. In order to research the migration of surrounding rock and coal in steeply inclined super high seams which used fully mechanized top coal caving, a working face of a certain mine was made as an example, analyzed the migration law of the overlay rock and coal under different caving ratio of fully mechanized top coal caving with numerical simulation analysis. The results suggest that the laws of overlay rock deformation caused by deeply inclined coal seam were different from horizontal coal seam. On the inclined direction, with an increase of dip angle and caving ratio, the vertical displacement of overlay rock and coal became greater, the asymmetric phenomenon of vertical displacement became obvious. On the trend direction, active region and transition region in goaf became smaller along with the increase of mining and caving ratio. On the contrary, the stable region area became greater. Therefore, there was an essential difference between the mechanism of surface movement deformation with deeply inclined coal seam and that with horizontal coal seam.

Modeling degradation and failure of Ni-Cr-Al overlay coatings

NASA Technical Reports Server (NTRS)

Nesbitt, J. A.; Heckel, R. W.

1984-01-01

Degradation of a Ni-16Cr-25Al-0.06Zr overlay coating on a Ni-22Cr substrate was examined after oxidation accompanied by thermal cycling. Concentration/distance profiles were measured in the coating and substrate after various one-hour cycles at 1150 C. A numerical model was developed to simulate coating degradation by simultaneous oxidation and coating/substrate interdiffusion. The validity of the model was confirmed by comparison of predicted and measured concentration/distance profiles. The ability of the model to identify critical system parameters was demonstrated for the case of the initial Al and Cr content of the coating and substrate.

Thickness shear mode (TSM) resonators used for biosensing

NASA Astrophysics Data System (ADS)

Bailey, Claude A.; Fiebor, Ben; Yen, Wei; Vodyanoy, Vitaly; Cernosek, Richard W.; Chin, Bryan A.

2002-02-01

The Auburn University Detection and Food Safety Center has demonstrated real-time biosensor for the detection of Salmonella typimhurium, consisting of a thickness shear-mode (TSM) quartz resonator with antibodies immobilized in a Langmuir-Blodgett surface film. Scanning Electron Microscopy (SEM) images of bound Salmonella bacteria to both polished and unpolished TSM resonators were taken to correlate the mass of the bound organism to the Sauerbrey equation. Theoretical frequency shifts for unpolished TSM resonators predicted by the Sauerbrey equation are much smaller than experimentally measured frequency shift. The Salmonella detector operates in a liquid environment. The viscous properties of this liquid overlayer could influence the TSM resonator's response. Various liquid media were studied as a function of temperature (0 to 50 degree(s)C). The chicken exudate samples with varying fat content show coagulation occurring at temperatures above 35 degree(s)C. Kinematic viscosity test were performed with buffer solutions containing varying quantities of Salmonella bacteria. Since the TSM resonators only entrain a boundary layer of fluid near the surface, they do not respond to these background viscous property changes. Bilk viscosity increases when bacteria concentrations are high. This paper describes investigations of TSM resonator surface acoustic interactions - mass, fluid viscosity, and viscoelasticity - that affect the sensor.

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

DOT National Transportation Integrated Search

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...

Texas flexible pavements and overlays : interim report for phases 2 and 3 - data collection and model calibration.

DOT National Transportation Integrated Search

2017-05-01

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 v...

Overlay of multiframe SEM images including nonlinear field distortions

NASA Astrophysics Data System (ADS)

Babin, S.; Borisov, S.; Ivonin, I.; Nakazawa, S.; Yamazaki, Y.

2018-03-01

To reduce charging and shrinkage, CD-SEMs utilize low electron energies and multiframe imaging. This results in every next frame being altered due to stage and beam instability, as well as due to charging. Regular averaging of the frames blurs the edges; this directly effects the extracted values of critical dimensions. A technique was developed to overlay multiframe images without the loss of quality. This method takes into account drift, rotation, and magnification corrections, as well as nonlinear distortions due to wafer charging. A significant improvement in the signal to noise ratio and overall image quality without degradation of the feature's edge quality was achieved. The developed software is capable of working with regular and large size images up to 32K pixels in each direction.

Improving management performance of P2PSIP for mobile sensing in wireless overlays.

PubMed

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.

Improving Management Performance of P2PSIP for Mobile Sensing in Wireless Overlays

PubMed Central

Sendín-Raña, Pablo; González-Castaño, Francisco Javier; Gómez-Cuba, Felipe; Asorey-Cacheda, Rafael; Pousada-Carballo, José María

2013-01-01

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 PMID:24217358

Hot Corrosion of Inconel 625 Overlay Weld Cladding in Smelting Off-Gas Environment

NASA Astrophysics Data System (ADS)

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.

Ultra-thin whitetopping for general aviation airports in New Mexico.

DOT National Transportation Integrated Search

2002-06-01

Whitetopping is a pavement rehabilitation construction practice where portland cement concrete (PCC) is placed over an existing asphalt concrete pavement as an overlay. Ultra-thin whitetopping (UTW) is generally a thin overlay with a thickness betwee...

Interacting epidemics on overlay networks

NASA Astrophysics Data System (ADS)

Funk, Sebastian; Jansen, Vincent A. A.

2010-03-01

The interaction between multiple pathogens spreading on networks connecting a given set of nodes presents an ongoing theoretical challenge. Here, we aim to understand such interactions by studying bond percolation of two different processes on overlay networks of arbitrary joint degree distribution. We find that an outbreak of a first pathogen providing immunity to another one spreading subsequently on a second network connecting the same set of nodes does so most effectively if the degrees on the two networks are positively correlated. In that case, the protection is stronger the more heterogeneous the degree distributions of the two networks are. If, on the other hand, the degrees are uncorrelated or negatively correlated, increasing heterogeneity reduces the potential of the first process to prevent the second one from reaching epidemic proportions. We generalize these results to cases where the edges of the two networks overlap to arbitrary amount, or where the immunity granted is only partial. If both processes grant immunity to each other, we find a wide range of possible situations of coexistence or mutual exclusion, depending on the joint degree distribution of the underlying networks and the amount of immunity granted mutually. These results generalize the concept of a coexistence threshold and illustrate the impact of large-scale network structure on the interaction between multiple spreading agents.

An evaluation of two bridge deck overlay systems on the Rte. 85 bridges over the Roanoke River.

DOT National Transportation Integrated Search

1971-01-01

Because of exposed reinforcing steel in some areas of the decks, the interstate route 85 bridges over the Roanoke River were treated with overlays in August 1969. In order to evaluate two different materials on a comparative basis, the Department of ...

Proteins detection by polymer optical fibers sensitised with overlayers of block and random copolymers

NASA Astrophysics Data System (ADS)

El Sachat, Alexandros; Meristoudi, Anastasia; Markos, Christos; Pispas, Stergios; Riziotis, Christos

2014-03-01

A low cost and low complexity optical detection method of proteins is presented by employing a detection scheme based on electrostatic interactions, and implemented by sensitization of a polymer optical fibers' (POF) surface by thin overlayers of properly designed sensitive copolymer materials with predesigned charges. This method enables the fast detection of proteins having opposite charge to the overlayer, and also the effective discrimination of differently charged proteins like lysozyme (LYS) and bovine serum albumin (BSA). As sensitive materials the block and the random copolymers of the same monomers were employed, namely the block copolymer poly(styrene-b-2vinylpyridine) (PS-b- P2VP) and the corresponding random copolymer poly(styrene-r-2vinylpyridine) (PS-r-P2VP), of similar composition and molecular weights. Results show systematically different response between the block and the random copolymers, although of the same order of magnitude, drawing thus important conclusions on their applications' techno-economic aspects given that they have significantly different associated manufacturing method and costs. The use of the POF platform, in combination with those adaptable copolymer sensing materials could lead to efficient low cost bio-detection schemes.

Oral rehabilitation of a patient with amelogenesis imperfecta using removable overlay denture: a clinical report.

PubMed

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.

Complete Imageless solution for overlay front-end manufacturing

NASA Astrophysics Data System (ADS)

Herisson, David; LeCacheux, Virginie; Touchet, Mathieu; Vachellerie, Vincent; Lecarpentier, Laurent; Felten, Franck; Polli, Marco

2005-09-01

Imageless option of KLA-Tencor RDM system (Recipe Data Management) is a new method of recipe creation, using only the mask design to define alignment target and measurement parameters. This technique is potentially the easiest tool to improve recipe management of a large amount of products in logic fab. Overlay recipes are created without wafer, by using a synthetic image (copy of gds mask file) for alignment pattern and target design like shape (frame in frame) and size for the measurement. A complete gauge study on critical CMOS 90nm Gate level has been conducted to evaluate reliability and robustness of the imageless recipe. We show that Imageless limits drastically the number of templates used for recipe creation, and improves or maintains measurement capability compare to manual recipe creation (operator dependant). Imageless appears to be a suitable solution for high volume manufacturing, as shown by the results obtained on production lots.

Reaction of Rb and oxygen overlayers with single-crystalline Bi2Sr2CaCu2O8+δ superconductors

NASA Astrophysics Data System (ADS)

Lindberg, P. A. P.; Shen, Z.-X.; Wells, B. O.; Dessau, D. S.; Mitzi, D. B.; Lindau, I.; Spicer, W. E.; Kapitulnik, A.

1989-02-01

Single crystals of Bi2Sr2CaCu2O8+δ superconductors, in situ cleaved and modified by Rb and oxygen overlayers, have been studied using ultraviolet and x-ray photoemission spectroscopy. The core-level results show that Rb strongly reacts with the Bi and O states, while the Cu and Sr states are left unchanged. This observation strongly indicates that the Bi-O plane forms the surface layer. Subsequent exposure to oxygen results in new oxygen states at the surface as monitored by the O 1s core-level data. For both Rb and oxygen overlayers the valence-band spectra are severely altered. In particular, new valence-band states, presumably of oxygen character, are formed.

In-Line Ultrasonic Monitoring for Sediments Stuck on Inner Wall of a Polyvinyl Chloride Pipe

PubMed Central

2014-01-01

This research verified the applicability and effectiveness of the ultrasonic monitoring of sediments stuck on the inner wall of polyvinyl chloride (PVC) pipes. For identifying the transmittance of acoustic energy and the speed of sound in the PVC material, the pulse-echo ultrasonic testing was conducted for PVC sheets of different thicknesses. To simulate the solidified sediment, the hot melt adhesive (HMA) was covered on the inner wall of the PVC pipe in different heights. From the experiment, the speeds of sound in the PVC and the HMA materials were obtained as about 2258 and 2000 m/s, respectively. The thickness of the materials was calculated through the signal processing such as taking the absolute value and low pass filtering, the echo detection, and the measurement of the time of flight. The errors between actual and measured thicknesses of PVC sheets were below 5%. In the case of the substance stuck on the inner wall, the errors were below 2.5%. Since the pulse-echo ultrasonic inspection is available on the outer surface and its measurement accuracy was over 95%, it can be an efficient and effective in-service structural health monitoring for the sediment on the wall of PVC pipes. PMID:25243223

Decoupling of Solid 4He Layers under the Superfluid Overlayer

NASA Astrophysics Data System (ADS)

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.

Estimate of the Impact of Absorbing Aerosol Over Cloud on the MODIS Retrievals of Cloud Optical Thickness and Effective Radius Using Two Independent Retrievals of Liquid Water Path

NASA Technical Reports Server (NTRS)

Wilcox, Eric M.; Harshvardhan; Platnick, Steven

2009-01-01

Two independent satellite retrievals of cloud liquid water path (LWP) from the NASA Aqua satellite are used to diagnose the impact of absorbing biomass burning aerosol overlaying boundary-layer marine water clouds on the Moderate Resolution Imaging Spectrometer (MODIS) retrievals of cloud optical thickness (tau) and cloud droplet effective radius (r(sub e)). In the MODIS retrieval over oceans, cloud reflectance in the 0.86-micrometer and 2.13-micrometer bands is used to simultaneously retrieve tau and r(sub e). A low bias in the MODIS tau retrieval may result from reductions in the 0.86-micrometer reflectance, which is only very weakly absorbed by clouds, owing to absorption by aerosols in cases where biomass burning aerosols occur above water clouds. MODIS LWP, derived from the product of the retrieved tau and r(sub e), is compared with LWP ocean retrievals from the Advanced Microwave Scanning Radiometer-EOS (AMSR-E), determined from cloud microwave emission that is transparent to aerosols. For the coastal Atlantic southern African region investigated in this study, a systematic difference between AMSR-E and MODIS LWP retrievals is found for stratocumulus clouds over three biomass burning months in 2005 and 2006 that is consistent with above-cloud absorbing aerosols. Biomass burning aerosol is detected using the ultraviolet aerosol index from the Ozone Monitoring Instrument (OMI) on the Aura satellite. The LWP difference (AMSR-E minus MODIS) increases both with increasing tau and increasing OMI aerosol index. During the biomass burning season the mean LWP difference is 14 g per square meters, which is within the 15-20 g per square meter range of estimated uncertainties in instantaneous LWP retrievals. For samples with only low amounts of overlaying smoke (OMI AI less than or equal to 1) the difference is 9.4, suggesting that the impact of smoke aerosols on the mean MODIS LWP is 5.6 g per square meter. Only for scenes with OMI aerosol index greater than 2 does the

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

PubMed

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.

Characterization of the Interface of an Alloy 625 Overlay on Steels Using Nanoindentation

NASA Astrophysics Data System (ADS)

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.

Ru sub 3 (CO) sub 12 and Mo (CO) sub 6 overlayers adsorbed on Ru(001) and Au/Ru and their interaction with electrons and photons: An infrared reflection--absorption study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malik, I.J.; Hrbek, J.

1991-05-01

We studied adsorbed Ru{sub 3}(CO){sub 12} and Mo (CO){sub 6} overlayers on Ru(001) and Au/Ru surfaces by infrared reflection--absorption spectroscopy (IRAS) and thermal desorption spectroscopy (TDS). We characterized the C--O stretching mode of both metal carbonyls (4 cm{sup {minus}1} FWHM) and a deformation mode of Mo (CO){sub 6} at 608 cm{sup {minus}1} with an unusually narrow FWHM of 1 cm{sup {minus}1}. Both IRAS and TDS data suggest adsorption and desorption of metal carbonyls as molecular species with a preferential orientation in the overlayers. We discuss annealing experiments of Ru{sub 3}(CO){sub 12}/Ru(001), the interaction of Ru{sub 3}(CO){sub 12} overlayers with electronsmore » of up to 100-eV energy, and the interaction of Mo (CO){sub 6} overlayers with 300-nm photons.« less

The Interplanetary Overlay Networking Protocol Accelerator

NASA Technical Reports Server (NTRS)

Pang, Jackson; Torgerson, Jordan L.; Clare, Loren P.

2008-01-01

A document describes the Interplanetary Overlay Networking Protocol Accelerator (IONAC) an electronic apparatus, now under development, for relaying data at high rates in spacecraft and interplanetary radio-communication systems utilizing a delay-tolerant networking protocol. The protocol includes provisions for transmission and reception of data in bundles (essentially, messages), transfer of custody of a bundle to a recipient relay station at each step of a relay, and return receipts. Because of limitations on energy resources available for such relays, data rates attainable in a conventional software implementation of the protocol are lower than those needed, at any given reasonable energy-consumption rate. Therefore, a main goal in developing the IONAC is to reduce the energy consumption by an order of magnitude and the data-throughput capability by two orders of magnitude. The IONAC prototype is a field-programmable gate array that serves as a reconfigurable hybrid (hardware/ firmware) system for implementation of the protocol. The prototype can decode 108,000 bundles per second and encode 100,000 bundles per second. It includes a bundle-cache static randomaccess memory that enables maintenance of a throughput of 2.7Gb/s, and an Ethernet convergence layer that supports a duplex throughput of 1Gb/s.

Survival Rate of Resin and Ceramic Inlays, Onlays, and Overlays: A Systematic Review and Meta-analysis.

PubMed

Morimoto, S; Rebello de Sampaio, F B W; Braga, M M; Sesma, N; Özcan, M

2016-08-01

This systematic review and meta-analysis aimed to evaluate the survival rate of ceramic and resin inlays, onlays, and overlays and to identify the complication types associated with the main clinical outcomes. Two reviewers searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials for articles published between 1983 through April 2015, conforming to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for systematic reviews. Clinical studies meeting the following criteria were included: 1) studies related to resin and ceramic inlays, onlays, and overlays; 2) prospective, retrospective, or randomized controlled trials conducted in humans; 3) studies with a dropout rate of less than 30%; and 4) studies with a follow-up longer than 5 y. Of 1,389 articles, 14 met the inclusion criteria. The meta-regression indicated that the type of ceramic material (feldspathic porcelain vs. glass-ceramic), study design (retrospective vs. prospective), follow-up time (5 vs. 10 y), and study setting (university vs. private clinic) did not affect the survival rate. Estimated survival rates for glass-ceramics and feldspathic porcelain were between 92% and 95% at 5 y (n = 5,811 restorations) and were 91% at 10 y (n = 2,154 restorations). Failures were related to fractures/chipping (4%), followed by endodontic complications (3%), secondary caries (1%), debonding (1%), and severe marginal staining (0%). Odds ratios (95% confidence intervals) were 0.19 (0.04 to 0.96) and 0.54 (0.17 to 1.69) for pulp vitality and type of tooth involved (premolars vs. molars), respectively. Ceramic inlays, onlays, and overlays showed high survival rates at 5 y and 10 y, and fractures were the most frequent cause of failure. © International & American Associations for Dental Research 2016.

Cytotoxicity of dental alloys, metals, and ceramics assessed by millipore filter, agar overlay, and MTT tests.

PubMed

Sjögren, G; Sletten, G; Dahl, J E

2000-08-01

Biocompatibility of dental materials is dependent on the release of elements from the materials. In addition, the composition, pretreatment, and handling of the materials influence the element release. This study evaluated the cytotoxicity of dental alloys, metals, and ceramics, with specific emphasis on the effects of altering the composition and the pretreatment. By using cells from a mouse fibroblast cell line and the agar overlay test, Millipore filter test, and MTT test, cytotoxicity of various metals, metal alloys, and ceramics for dental restoration were studied. Effects of altering the composition of a high noble gold alloy and of pretreatment of a ceramic-bonding alloy were also studied. In addition, the release of elements into the cell culture medium by the materials studied was measured using an inductively coupled plasma optical emission spectrophotometer. The results of the MTT test were analyzed statistically using ANOVA and Scheffé test at a significance level of P <.05. Specimens manufactured from materials intended for dental restorations and handled in accordance with the manufacturers' instructions were ranked from "noncytotoxic" to "mildly cytotoxic" according to the agar overlay and Millipore filter tests. For the MTT test, no significant differences were observed between these materials and controls, with the exception of JS C-gold and unalloyed titanium. The modified materials were ranked from "mildly cytotoxic" to "moderately cytotoxic" in the agar overlay and Millipore filter tests and from "noncytotoxic" to "moderately cytotoxic" in the MTT test. Thus, cytotoxicity was related to the alloy composition and treatment. The release of Cu and Zn seemed to be important for the cytotoxic effect. Alterations in the composition and the pretreatment can greatly influence the cytotoxicity, and the results stress the importance of carefully following the manufacturers' instructions when handling dental materials.

Reestablishment of occlusion through overlay removable partial dentures: a case report.

PubMed

Bataglion, César; Hotta, Takami Hirono; Matsumoto, Wilson; Ruellas, Carlos Ventura de Oliveira

2012-01-01

Loss of posterior teeth may cause an imbalance in the stomatognathic system. Overlay removable partial dentures (ORPD) are a reversible and relatively inexpensive treatment for patients with severely worn teeth. This paper presents a treatment with ORPD in a 55-year-old male patient who had severe attrition in the maxillary and mandibular teeth, temporomandibular joint pain and reduced vertical dimension of occlusion (VDO). The treatment consisted in the reestablishment of the VDO using Lucia's jig, fabricating removable partial denture with reconstruction of the worn teeth without preparation. This therapy can be used as an alternative treatment to provide esthetic, function and stable occlusion in patients with severely worn teeth.

Flutter Sensitivity to Boundary Layer Thickness, Structural Damping, and Static Pressure Differential for a Shuttle Tile Overlay Repair Concept

NASA Technical Reports Server (NTRS)

Scott, Robert C.; Bartels, Robert E.

2009-01-01

This paper examines the aeroelastic stability of an on-orbit installable Space Shuttle patch panel. CFD flutter solutions were obtained for thick and thin boundary layers at a free stream Mach number of 2.0 and several Mach numbers near sonic speed. The effect of structural damping on these flutter solutions was also examined, and the effect of structural nonlinearities associated with in-plane forces in the panel was considered on the worst case linear flutter solution. The results of the study indicated that adequate flutter margins exist for the panel at the Mach numbers examined. The addition of structural damping improved flutter margins as did the inclusion of nonlinear effects associated with a static pressure difference across the panel.

Protein Biochemistry and Expression Regulation of Cadmium/Zinc Pumping ATPases in the Hyperaccumulator Plants Arabidopsis halleri and Noccaea caerulescens

PubMed Central

Mishra, Seema; Mishra, Archana; Küpper, Hendrik

2017-01-01

P1B-ATPases are decisive for metal accumulation phenotypes, but mechanisms of their regulation are only partially understood. Here, we studied the Cd/Zn transporting ATPases NcHMA3 and NcHMA4 from Noccaea caerulescens as well as AhHMA3 and AhHMA4 from Arabidopsis halleri. Protein biochemistry was analyzed on HMA4 purified from roots of N. caerulescens in active state. Metal titration of NcHMA4 protein with an electrochromic dye as charge indicator suggested that HMA4 reaches maximal ATPase activity when all internal high-affinity Cd2+ binding sites are occupied. Although HMA4 was reported to be mainly responsible for xylem loading of heavy metals for root to shoot transport, the current study revealed high expression of NcHMA4 in shoots as well. Further, there were additional 20 and 40 kD fragments at replete Zn2+ and toxic Cd2+, but not at deficient Zn2+ concentrations. Altogether, the protein level expression analysis suggested a more multifunctional role of NcHMA4 than previously assumed. Organ-level transcription analysis through quantitative PCR of mRNA in N. caerulescens and A. halleri confirmed the strong shoot expression of both NcHMA4 and AhHMA4. Further, in shoots NcHMA4 was more abundant in 10 μM Zn2+ and AhHMA4 in Zn2+ deficiency. In roots, NcHMA4 was up-regulated in response to deficient Zn2+ when compared to replete Zn2+ and toxic Cd2+ treatment. In both species, HMA3 was much more expressed in shoots than in roots, and HMA3 transcript levels remained rather constant regardless of Zn2+ supply, but were up-regulated by 10 μM Cd2+. Analysis of cellular expression by quantitative mRNA in situ hybridisation showed that in A. halleri, both HMA3 and HMA4 mRNA levels were highest in the mesophyll, while in N. caerulescens they were highest in the bundle sheath of the vein. This is likely related to the different final storage sites for hyperaccumulated metals in both species: epidermis in N. caerulescens, mesophyll in A. halleri. PMID:28588597

Protein Biochemistry and Expression Regulation of Cadmium/Zinc Pumping ATPases in the Hyperaccumulator Plants Arabidopsis halleri and Noccaea caerulescens.

PubMed

Mishra, Seema; Mishra, Archana; Küpper, Hendrik

2017-01-01

P 1B -ATPases are decisive for metal accumulation phenotypes, but mechanisms of their regulation are only partially understood. Here, we studied the Cd/Zn transporting ATPases NcHMA3 and NcHMA4 from Noccaea caerulescens as well as AhHMA3 and AhHMA4 from Arabidopsis halleri . Protein biochemistry was analyzed on HMA4 purified from roots of N. caerulescens in active state. Metal titration of NcHMA4 protein with an electrochromic dye as charge indicator suggested that HMA4 reaches maximal ATPase activity when all internal high-affinity Cd 2+ binding sites are occupied. Although HMA4 was reported to be mainly responsible for xylem loading of heavy metals for root to shoot transport, the current study revealed high expression of NcHMA4 in shoots as well. Further, there were additional 20 and 40 kD fragments at replete Zn 2+ and toxic Cd 2+ , but not at deficient Zn 2+ concentrations. Altogether, the protein level expression analysis suggested a more multifunctional role of NcHMA4 than previously assumed. Organ-level transcription analysis through quantitative PCR of mRNA in N. caerulescens and A. halleri confirmed the strong shoot expression of both NcHMA4 and AhHMA4 . Further, in shoots NcHMA4 was more abundant in 10 μM Zn 2+ and AhHMA4 in Zn 2+ deficiency. In roots, NcHMA4 was up-regulated in response to deficient Zn 2+ when compared to replete Zn 2+ and toxic Cd 2+ treatment. In both species, HMA3 was much more expressed in shoots than in roots, and HMA3 transcript levels remained rather constant regardless of Zn 2+ supply, but were up-regulated by 10 μM Cd 2+ . Analysis of cellular expression by quantitative mRNA in situ hybridisation showed that in A. halleri , both HMA3 and HMA4 mRNA levels were highest in the mesophyll, while in N. caerulescens they were highest in the bundle sheath of the vein. This is likely related to the different final storage sites for hyperaccumulated metals in both species: epidermis in N. caerulescens , mesophyll in A. halleri .

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

ERIC Educational Resources Information Center

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,…

Latex modified asphalt and experimental joint treatments on asphalt concrete overlays experimental project No. 3 : asphalt additives : final report.

DOT National Transportation Integrated Search

1991-06-01

This report documents the construction, initial evaluation and final evaluation of several experimental features which were incorporated as part of an overlay of an existing PCC pavement in order to determine the feasibility of extending the asphalti...

Cleaning of copper traces on circuit boards with excimer laser radiation

NASA Astrophysics Data System (ADS)

Wesner, D. A.; Mertin, M.; Lupp, F.; Kreutz, E. W.

1996-04-01

Cleaning of Cu traces on circuit boards is studied using pulsed excimer laser radiation (pulse width ˜ 20 ns, wavelength 248 nm), with the goal of improving the properties of the Cu surface for soldering and bonding. Traces with well-defined oxide overlayers are cleaned by irradiation in air using ≤ 10 3 laser pulses at fluences per pulse of ≤ 2 J cm -2. After treatment the surface morphology is analyzed using optical microscopy, optical profilometry, and scanning electron microscopy, while the chemical state of the surface is investigated with X-ray photoelectron (XPS) spectroscopy. Ellipsometry is used to determine the oxide overlayer thickness. Prior to cleaning samples exhibit a contamination overlayer about 15-25 nm in thickness containing Cu 2O and C. Cleaning reduces the overlayer thickness to ≤ 10 nm by material removal. The process tends to be self-limiting, since the optical reflectivity of the oxidized Cu surface for laser radiation is smaller than that of the cleaned surface. Additionally, the interaction with the laser radiation results in surface segregation of a minor alloy component out of the bulk (e.g. Zn), which may help to passivate the surface for further chemical reactions.

Magnetism of a Co monolayer on Pt(111) capped by overlayers of 5 d elements: A spin-model study

NASA Astrophysics Data System (ADS)

Simon, E.; Rózsa, L.; Palotás, K.; Szunyogh, L.

2018-04-01

Using first-principles calculations, we study the magnetic properties of a Co monolayer on a Pt(111) surface with a capping monolayer of selected 5 d elements (Re, Os, Ir, Pt, and Au). First we determine the tensorial exchange interactions and magnetic anisotropies characterizing the Co monolayer for all considered systems. We find a close relationship between the magnetic moment of the Co atoms and the nearest-neighbor isotropic exchange interaction, which is attributed to the electronic hybridization between the Co and the capping layers, in the spirit of the Stoner picture of ferromagnetism. The Dzyaloshinskii-Moriya interaction is decreased for all overlayers compared to the uncapped Co/Pt(111) system, while even the sign of the Dzyaloshinskii-Moriya interaction changes in the case of the Ir overlayer. We conclude that the variation of the Dzyaloshinskii-Moriya interaction is well correlated with the change of the magnetic anisotropy energy and of the orbital moment anisotropy. The unique influence of the Ir overlayer on the Dzyaloshinskii-Moriya interaction is traced by scaling the strength of the spin-orbit coupling of the Ir atoms in Ir/Co/Pt(111) and by changing the Ir concentration in the Au1 -xIrx /Co/Pt(111) system. Our spin dynamics simulations indicate that the magnetic ground state of Re/Co/Pt(111) thin film is a spin spiral with a tilted normal vector, while the other systems are ferromagnetic.

Latex modified fibrous concrete : experimental feature : final report.

DOT National Transportation Integrated Search

1985-03-01

In November 1980, a contractor requested permission to use a 1.5 inch thick Latex Modified Fibrous Concrete (LMFC) overlay in lieu of a 2.5 inch low slump concrete (Iowa System) or a 2.5 inch unreinforced latex modified concrete. The overlays were to...

Latex modified fibrous concrete Sundial-Sandy River Section : interim report.

DOT National Transportation Integrated Search

1985-03-01

In November 1980, a contractor requested permission to use a 1.5 inch thick Latex Modified Fibrous Concrete (LMFC) overlay in lieu of a 2.5 inch low slump concrete (Iowa System) or a 2.5 inch unreinforced latex modified concrete. The overlays were to...

Overlay performance assessment of MAPPER's FLX-1200 (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lattard, Ludovic; Servin, Isabelle; Pradelles, Jonathan; Blancquaert, Yoann; Rademaker, Guido; Pain, Laurent; de Boer, Guido; Brandt, Pieter; Dansberg, Michel; Jager, Remco J. A.; Peijster, Jerry J. M.; Slot, Erwin; Steenbrink, Stijn W. H. K.; Vergeer, Niels; Wieland, Marco

2017-04-01

Mapper Lithography has introduced its first product, the FLX-1200, which is installed at CEA-Leti in Grenoble (France). This is a mask less lithography system, based on massively parallel electron-beam writing with high-speed optical data transport for switching the electron beams. This FLX platform is initially targeted for 1 wph performance for 28 nm technology nodes, but can also be used for less demanding imaging. The electron source currently integrated is capable of scaling to 10 wph at the same resolution performance, which will be implemented by gradually upgrading the illumination optics. The system has an optical alignment system enabling mix-and-match with optical 193 nm immersion systems using standard NVSM marks. The tool at CEA-Leti is in-line with a Sokudo Duo clean track. Mapper Lithography and CEA-Leti are working in collaboration to develop turnkey solution for specific applications. At previous conferences we have presented imaging results including 28nm node resolution, cross wafer CDu of 2.5nm 3 and a throughput of half a wafer per hour, overhead times included. At this conference we will present results regarding the overlay performance of the FLX-1200. In figure 2 an initial result towards measuring the overlay performance of the FLX-1200 is shown. We have exposed a wafer twice without unloading the wafer in between exposures. In the first exposure half of a dense dot array is exposed. In the second exposure the remainder of the dense dot array is exposed. After development the wafer has been inspected using a CD-SEM at 480 locations distributed over an area of 100mm x 100mm. For each SEM image the shift of the pattern written in the first exposure relative to the pattern written in the second exposure is measured. Cross wafer this shift is 7 nm u+3s in X and 5 nm u+3s in Y. The next step is to evaluate the impact of unloading and loading of the wafer in between exposures. At the conference the latest results will be presented.

Successful treatment of direct carotid-cavernous fistula in a patient with Ehlers-Danlos syndrome type IV without arterial puncture: the transvenous triple-overlay embolization (TAILOREd) technique.

PubMed

Huynh, Thien J; Morton, Ryan P; Levitt, Michael R; Ghodke, Basavaraj V; Wink, Onno; Hallam, Danial K

2017-08-18

We report successful transvenous treatment of direct carotid-cavernous fistula in a patient with Ehlers-Danlos syndrome type IV using a novel triple-overlay embolization (TAILOREd) technique without the need for arterial puncture, which is known to be highly risky in this patient group. The TAILOREd technique allowed for successful treatment using preoperative MR angiography as a three-dimensional overlay roadmap combined with cone beam CT and live fluoroscopy, precluding the need for an arterial puncture. 2017 BMJ Publishing Group Ltd.

CFD-Predicted Tile Heating Bump Factors Due to Tile Overlay Repairs

NASA Technical Reports Server (NTRS)

Lessard, Victor R.

2006-01-01

A Computational Fluid Dynamics investigation of the Orbiter's Tile Overlay Repair (TOR) is performed to assess the aeroheating Damage Assessment Team's (DAT) existing heating correlation method for protuberance interference heating on the surrounding thermal protection system. Aerothermodynamic heating analyses are performed for TORs at the design reference damage locations body points 1800 and 1075 for a Mach 17.9 and a=39deg STS-107 flight trajectory point with laminar flow. Six different cases are considered. The computed peak heating bump factor on the surrounding tiles are below the DAT's heating bump factor values for smooth tile cases. However, for the uneven tiles cases the peak interference heating is shown to be considerably higher than the existing correlation prediction.

Creating Interactive Graphical Overlays in the Advanced Weather Interactive Processing System (AWIPS) Using Shapefiles and DGM Files

NASA Technical Reports Server (NTRS)

Barrett, Joe H., III; Lafosse, Richard; Hood, Doris; Hoeth, Brian

2007-01-01

Graphical overlays can be created in real-time in the Advanced Weather Interactive Processing System (AWIPS) using shapefiles or DARE Graphics Metafile (DGM) files. This presentation describes how to create graphical overlays on-the-fly for AWIPS, by using two examples of AWIPS applications that were created by the Applied Meteorology Unit (AMU). The first example is the Anvil Threat Corridor Forecast Tool, which produces a shapefile that depicts a graphical threat corridor of the forecast movement of thunderstorm anvil clouds, based on the observed or forecast upper-level winds. This tool is used by the Spaceflight Meteorology Group (SMG) and 45th Weather Squadron (45 WS) to analyze the threat of natural or space vehicle-triggered lightning over a location. The second example is a launch and landing trajectory tool that produces a DGM file that plots the ground track of space vehicles during launch or landing. The trajectory tool can be used by SMG and the 45 WS forecasters to analyze weather radar imagery along a launch or landing trajectory. Advantages of both file types will be listed.

Simple Magnetic Device Indicates Thickness Of Alloy 903

NASA Technical Reports Server (NTRS)

Long, Pin Jeng; Rodriguez, Sergio; Bright, Mark L.

1995-01-01

Handheld device called "ferrite indicator" orginally designed for use in determining ferrite content of specimen of steel. Placed in contact with specimen and functions by indicating whether magnet attracted more strongly to specimen or to calibrated reference sample. Relative strength of attraction shows whether alloy overlay thinner than allowable.

Study of spread spectrum multiple access systems for satellite communications with overlay on current services

NASA Technical Reports Server (NTRS)

Ha, Tri T.; Pratt, Timothy

1989-01-01

The feasibility of using spread spectrum techniques to provide a low-cost multiple access system for a very large number of low data terminals was investigated. Two applications of spread spectrum technology to very small aperture terminal (VSAT) satellite communication networks are presented. Two spread spectrum multiple access systems which use a form of noncoherent M-ary FSK (MFSK) as the primary modulation are described and the throughput analyzed. The analysis considers such factors as satellite power constraints and adjacent satellite interference. Also considered is the effect of on-board processing on the multiple access efficiency and the feasibility of overlaying low data rate spread spectrum signals on existing satellite traffic as a form of frequency reuse is investigated. The use of chirp is examined for spread spectrum communications. In a chirp communication system, each data bit is converted into one or more up or down sweeps of frequency, which spread the RF energy across a broad range of frequencies. Several different forms of chirp communication systems are considered, and a multiple-chirp coded system is proposed for overlay service. The mutual interference problem is examined in detail and a performance analysis undertaken for the case of a chirp data channel overlaid on a video channel.

Large-Scale Overlays and Trends: Visually Mining, Panning and Zooming the Observable Universe.

PubMed

Luciani, Timothy Basil; Cherinka, Brian; Oliphant, Daniel; Myers, Sean; Wood-Vasey, W Michael; Labrinidis, Alexandros; Marai, G Elisabeta

2014-07-01

We introduce a web-based computing infrastructure to assist the visual integration, mining and interactive navigation of large-scale astronomy observations. Following an analysis of the application domain, we design a client-server architecture to fetch distributed image data and to partition local data into a spatial index structure that allows prefix-matching of spatial objects. In conjunction with hardware-accelerated pixel-based overlays and an online cross-registration pipeline, this approach allows the fetching, displaying, panning and zooming of gigabit panoramas of the sky in real time. To further facilitate the integration and mining of spatial and non-spatial data, we introduce interactive trend images-compact visual representations for identifying outlier objects and for studying trends within large collections of spatial objects of a given class. In a demonstration, images from three sky surveys (SDSS, FIRST and simulated LSST results) are cross-registered and integrated as overlays, allowing cross-spectrum analysis of astronomy observations. Trend images are interactively generated from catalog data and used to visually mine astronomy observations of similar type. The front-end of the infrastructure uses the web technologies WebGL and HTML5 to enable cross-platform, web-based functionality. Our approach attains interactive rendering framerates; its power and flexibility enables it to serve the needs of the astronomy community. Evaluation on three case studies, as well as feedback from domain experts emphasize the benefits of this visual approach to the observational astronomy field; and its potential benefits to large scale geospatial visualization in general.

Alkali-resistant low-temperature atomic-layer-deposited oxides for optical fiber sensor overlays

NASA Astrophysics Data System (ADS)

Kosiel, K.; Dominik, M.; Ściślewska, I.; Kalisz, M.; Guziewicz, M.; Gołaszewska, K.; Niedziółka-Jonsson, J.; Bock, W. J.; Śmietana, M.

2018-04-01

This paper presents an investigation of properties of selected metallic oxides deposited at a low temperature (100 °C) by atomic layer deposition (ALD) technique, relating to their applicability as thin overlays for optical fiber sensors resistant in alkaline environments. Hafnium oxide (Hf x O y with y/x approx. 2.70), tantalum oxide (Ta x O y with y/x approx. 2.75) and zirconium oxide (Zr x O y with y/x approx. 2.07), which deposition was based, respectively, on tetrakis(ethylmethyl)hafnium, tantalum pentachloride and tetrakis(ethylmethyl)zirconium with deionized water, were tested as thin layers on planar Si (100) and glass substrates. Growth per cycle (GPC) in the ALD processes was 0.133-0.150 nm/cycle. Run-to-run GPC reproducibility of the ALD processes was best for Hf x O y (0.145 ± 0.001 nm/cycle) and the poorest for Ta x O y (0.133 ± 0.003 nm/cycle). Refractive indices n of the layers were 2.00-2.10 (at the wavelength λ = 632 nm), with negligible k value (at λ for 240-930 nm). The oxides examined by x-ray diffractometry proved to be amorphous, with only small addition of crystalline phases for the Zr x O y . The surfaces of the oxides had grainy but smooth topographies with root-mean square roughness ˜0.5 nm (at 10 × 10 μm2 area) according to atomic force microscopy. Ellipsometric measurements, by contrast, suggest rougher surfaces for the Zr x O y layers. The surfaces were also slightly rougher on the glass-based samples than on the Si-based ones. Nanohardness and Young modules were 4.90-8.64 GPa and 83.7-104.4 GPa, respectively. The tests of scratch resistance revealed better tribological properties for the Hf x O y and the Ta x O y than for the Zr x O y . The surfaces were hydrophilic, with wetting angles of 52.5°-62.9°. The planar oxides on Si, being resistive even to concentrated alkali (pH 14), proved to be significantly more alkali-resistive than Al2O3. The Ta x O y overlay was deposited on long-period grating sensor induced in optical

Vision-based overlay of a virtual object into real scene for designing room interior

NASA Astrophysics Data System (ADS)

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).

Evaluation of the installation and initial condition of high performance concrete overlays placed on Route 60 over Lynnhaven Inlet in Virginia.

DOT National Transportation Integrated Search

1999-04-01

Sixteen high performance concrete overlays were placed on two 28-span bridges on Rte. 60 over Lynnhaven Inlet, Virginia Beach, : Virginia, in the spring of 1996. The construction was funded with 20 percent Virginia Department of Transportation mainte...

An Efficient, Scalable and Robust P2P Overlay for Autonomic Communication

NASA Astrophysics Data System (ADS)

Li, Deng; Liu, Hui; Vasilakos, Athanasios

The term Autonomic Communication (AC) refers to self-managing systems which are capable of supporting self-configuration, self-healing and self-optimization. However, information reflection and collection, lack of centralized control, non-cooperation and so on are just some of the challenges within AC systems. Since many self-* properties (e.g. selfconfiguration, self-optimization, self-healing, and self-protecting) are achieved by a group of autonomous entities that coordinate in a peer-to-peer (P2P) fashion, it has opened the door to migrating research techniques from P2P systems. P2P's meaning can be better understood with a set of key characteristics similar to AC: Decentralized organization, Self-organizing nature (i.e. adaptability), Resource sharing and aggregation, and Fault-tolerance. However, not all P2P systems are compatible with AC. Unstructured systems are designed more specifically than structured systems for the heterogeneous Internet environment, where the nodes' persistence and availability are not guaranteed. Motivated by the challenges in AC and based on comprehensive analysis of popular P2P applications, three correlative standards for evaluating the compatibility of a P2P system with AC are presented in this chapter. According to these standards, a novel Efficient, Scalable and Robust (ESR) P2P overlay is proposed. Differing from current structured and unstructured, or meshed and tree-like P2P overlay, the ESR is a whole new three dimensional structure to improve the efficiency of routing, while information exchanges take in immediate neighbors with local information to make the system scalable and fault-tolerant. Furthermore, rather than a complex game theory or incentive mechanism, asimple but effective punish mechanism has been presented based on a new ID structure which can guarantee the continuity of each node's record in order to discourage negative behavior on an autonomous environment as AC.

The Effect of pH on Slurry Erosion-Corrosion of Tungsten Carbide Overlays Alloyed with Ru

NASA Astrophysics Data System (ADS)

Nelwalani, Ndivhuwo B.; van der Merwe, Josias W.

2018-02-01

The aim of the study was to determine the effect of Ru additions to WC-Fe overlays when exposed to low pH slurry erosion conditions. These overlays were applied through Plasma Transferred Arc, and the original bulk Ru powder concentrations varied from 0.5 to 5 wt.%. A slurry jet impingement erosion-corrosion test rig was used to evaluate wear, and electrochemical measurements were performed to characterize the corrosion properties. The slurry mixtures contained silica sand and synthetic mine water. The pH was varied between 3 and 6.5 for the slurry erosion tests and lowered further for the corrosion characterization. Samples were examined optically and with a scanning electron microscope using energy-dispersive x-ray spectroscopy. X-ray diffraction analysis was used to determine the phases present. For the slurry erosion-corrosion results at the pH of 6.5, addition of Ru did not show a decrease in erosion-corrosion rates. However, when the pH was decreased to 3, by the addition of HCl, Ru improved the resistance. From the electrochemistry, it was also clear that Ru additions improved the corrosion resistance, but more than 1 wt.% Ru was required. At very low pH levels, the presence of Ru was not able to prevent corrosion.